sctp: move to plugins, disabled by default

Removed sctp buffer metadata from vnet/buffer.h, added it to the
plugin. Add registration APIs for plugin-based vlib_buffer_opaque /
opaque2 decoders, used by "pcap dispatch trace ..." for display in the
wireshark dissector.

Type:refactor

Not actively maintained.

Change-Id: Ie4cb6ba66f68b3b3a7d7d2c63c917fdccf994371
Signed-off-by: Florin Coras <fcoras@cisco.com>
Signed-off-by: Dave Barach <dave@barachs.net>

16 files changed, 8625 insertions, 0 deletions

diff --git a/src/plugins/sctp/CMakeLists.txt b/src/plugins/sctp/CMakeLists.txt
new file mode 100644
index 00000000000..0c28fe70524
--- /dev/null
+++ b/src/plugins/sctp/CMakeLists.txt
@@ -0,0 +1,38 @@
+# Copyright (c) 2019 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+add_vpp_plugin(sctp
+  SOURCES
+  sctp.c
+  sctp_api.c
+  sctp_pg.c
+  sctp_input.c
+  sctp_output.c
+  sctp_output_node.c
+  sctp_format.c
+
+  API_FILES
+  sctp.api
+  
+  MULTIARCH_SOURCES
+  sctp_output_node.c
+  sctp_input.c
+  
+  INSTALL_HEADERS
+  sctp_all_api_h.h
+  sctp_msg_enum.h
+  sctp_error.def
+  sctp_packet.h
+  sctp_timer.h
+  sctp.h
+)
diff --git a/src/plugins/sctp/sctp.api b/src/plugins/sctp/sctp.api
new file mode 100644
index 00000000000..fb228617216
--- /dev/null
+++ b/src/plugins/sctp/sctp.api
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2018 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+option version = "1.0.0";
+ 
+/** \brief Configure SCTP source addresses, for active-open SCTP sessions
+
+    SCTP src/dst ports are 16 bits
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param is_ipv6 - 1 for ipv6, 0 for ipv4
+    @param vrf_id - fib table / vrf id for local adjacencies
+    @param src_address - src address that SCTP will use for this sub-conn
+    @param dst_address - dst address that SCTP will use for this sub-conn
+*/
+autoreply define sctp_add_src_dst_connection {
+    u32 client_index;
+    u32 context;
+    u8 is_ipv6;
+    u32 vrf_id;
+    u8 src_address[16];
+    u8 dst_address[16];
+ };
+ 
+autoreply define sctp_del_src_dst_connection {
+    u32 client_index;
+    u32 context;
+    u8 is_ipv6;
+    u32 vrf_id;
+    u8 src_address[16];
+    u8 dst_address[16];
+ };
+ 
+autoreply define sctp_config {
+    u32 client_index;
+    u32 context;
+    u8 never_delay_sack;
+    u8 never_bundle;
+ };
\ No newline at end of file
diff --git a/src/plugins/sctp/sctp.c b/src/plugins/sctp/sctp.c
new file mode 100644
index 00000000000..14958e55d60
--- /dev/null
+++ b/src/plugins/sctp/sctp.c
@@ -0,0 +1,1128 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vnet/plugin/plugin.h>
+#include <vpp/app/version.h>
+
+#include <sctp/sctp.h>
+#include <sctp/sctp_debug.h>
+
+sctp_main_t sctp_main;
+
+static u32
+sctp_connection_bind (u32 session_index, transport_endpoint_t * tep)
+{
+  sctp_main_t *tm = &sctp_main;
+  sctp_connection_t *listener;
+  void *iface_ip;
+  u32 mtu = 1460;
+
+  pool_get (tm->listener_pool, listener);
+  clib_memset (listener, 0, sizeof (*listener));
+
+  listener->sub_conn[SCTP_PRIMARY_PATH_IDX].subconn_idx =
+    SCTP_PRIMARY_PATH_IDX;
+  listener->sub_conn[SCTP_PRIMARY_PATH_IDX].c_c_index =
+    listener - tm->listener_pool;
+  listener->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.lcl_port = tep->port;
+
+  /* If we are provided a sw_if_index, bind using one of its IPs */
+  if (ip_is_zero (&tep->ip, 1) && tep->sw_if_index != ENDPOINT_INVALID_INDEX)
+    {
+      if ((iface_ip = ip_interface_get_first_ip (tep->sw_if_index,
+						 tep->is_ip4)))
+	ip_set (&tep->ip, iface_ip, tep->is_ip4);
+    }
+  ip_copy (&listener->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.lcl_ip,
+	   &tep->ip, tep->is_ip4);
+
+  if (tep->sw_if_index != ENDPOINT_INVALID_INDEX)
+    mtu = tep->is_ip4 ? vnet_sw_interface_get_mtu (vnet_get_main (),
+						   tep->sw_if_index,
+						   VNET_MTU_IP4) :
+      vnet_sw_interface_get_mtu (vnet_get_main (), tep->sw_if_index,
+				 VNET_MTU_IP6);
+
+  listener->sub_conn[SCTP_PRIMARY_PATH_IDX].PMTU = mtu;
+  listener->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.is_ip4 = tep->is_ip4;
+  listener->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.proto =
+    TRANSPORT_PROTO_SCTP;
+  listener->sub_conn[SCTP_PRIMARY_PATH_IDX].c_s_index = session_index;
+  listener->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.fib_index =
+    tep->fib_index;
+  listener->state = SCTP_STATE_CLOSED;
+
+  sctp_connection_timers_init (listener);
+
+  return listener->sub_conn[SCTP_PRIMARY_PATH_IDX].c_c_index;
+}
+
+u32
+sctp_session_bind (u32 session_index, transport_endpoint_t * tep)
+{
+  return sctp_connection_bind (session_index, tep);
+}
+
+static void
+sctp_connection_unbind (u32 listener_index)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  sctp_connection_t *sctp_conn;
+
+  sctp_conn = pool_elt_at_index (tm->listener_pool, listener_index);
+
+  /* Poison the entry */
+  if (CLIB_DEBUG > 0)
+    clib_memset (sctp_conn, 0xFA, sizeof (*sctp_conn));
+
+  pool_put_index (tm->listener_pool, listener_index);
+}
+
+u32
+sctp_session_unbind (u32 listener_index)
+{
+  sctp_connection_unbind (listener_index);
+  return 0;
+}
+
+void
+sctp_punt_unknown (vlib_main_t * vm, u8 is_ip4, u8 is_add)
+{
+  sctp_main_t *tm = &sctp_main;
+  if (is_ip4)
+    tm->punt_unknown4 = is_add;
+  else
+    tm->punt_unknown6 = is_add;
+}
+
+static int
+sctp_alloc_custom_local_endpoint (sctp_main_t * tm, ip46_address_t * lcl_addr,
+				  u16 * lcl_port, u8 is_ip4)
+{
+  int index, port;
+  if (is_ip4)
+    {
+      index = tm->last_v4_address_rotor++;
+      if (tm->last_v4_address_rotor >= vec_len (tm->ip4_src_addresses))
+	tm->last_v4_address_rotor = 0;
+      lcl_addr->ip4.as_u32 = tm->ip4_src_addresses[index].as_u32;
+    }
+  else
+    {
+      index = tm->last_v6_address_rotor++;
+      if (tm->last_v6_address_rotor >= vec_len (tm->ip6_src_addresses))
+	tm->last_v6_address_rotor = 0;
+      clib_memcpy (&lcl_addr->ip6, &tm->ip6_src_addresses[index],
+		   sizeof (ip6_address_t));
+    }
+  port = transport_alloc_local_port (TRANSPORT_PROTO_SCTP, lcl_addr);
+  if (port < 1)
+    {
+      clib_warning ("Failed to allocate src port");
+      return -1;
+    }
+  *lcl_port = port;
+  return 0;
+}
+
+/**
+ * Initialize all connection timers as invalid
+ */
+void
+sctp_connection_timers_init (sctp_connection_t * sctp_conn)
+{
+  int i, j;
+
+  /* Set all to invalid */
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      sctp_conn->sub_conn[i].RTO = SCTP_RTO_INIT;
+
+      for (j = 0; j < SCTP_N_TIMERS; j++)
+	{
+	  sctp_conn->sub_conn[i].timers[j] = SCTP_TIMER_HANDLE_INVALID;
+	}
+    }
+}
+
+/**
+ * Stop all connection timers
+ */
+void
+sctp_connection_timers_reset (sctp_connection_t * sctp_conn)
+{
+  int i, j;
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      for (j = 0; j < SCTP_N_TIMERS; j++)
+	sctp_timer_reset (sctp_conn, i, j);
+    }
+}
+
+const char *sctp_fsm_states[] = {
+#define _(sym, str) str,
+  foreach_sctp_fsm_state
+#undef _
+};
+
+u8 *
+format_sctp_state (u8 * s, va_list * args)
+{
+  u32 state = va_arg (*args, u32);
+
+  if (state < SCTP_N_STATES)
+    s = format (s, "%s", sctp_fsm_states[state]);
+  else
+    s = format (s, "UNKNOWN (%d (0x%x))", state, state);
+  return s;
+}
+
+u8 *
+format_sctp_connection_id (u8 * s, va_list * args)
+{
+  sctp_connection_t *sctp_conn = va_arg (*args, sctp_connection_t *);
+  if (!sctp_conn)
+    return s;
+
+  u8 i;
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      if (i > 0 && sctp_conn->sub_conn[i].state == SCTP_SUBCONN_STATE_DOWN)
+	continue;
+      if (sctp_conn->sub_conn[i].connection.is_ip4)
+	{
+	  s = format (s, "[#%d][%s] %U:%d->%U:%d",
+		      sctp_conn->sub_conn[i].connection.thread_index,
+		      "S",
+		      format_ip4_address,
+		      &sctp_conn->sub_conn[i].connection.lcl_ip.ip4,
+		      clib_net_to_host_u16 (sctp_conn->sub_conn[i].
+					    connection.lcl_port),
+		      format_ip4_address,
+		      &sctp_conn->sub_conn[i].connection.rmt_ip.ip4,
+		      clib_net_to_host_u16 (sctp_conn->sub_conn[i].
+					    connection.rmt_port));
+	}
+      else
+	{
+	  s = format (s, "[#%d][%s] %U:%d->%U:%d",
+		      sctp_conn->sub_conn[i].connection.thread_index,
+		      "S",
+		      format_ip6_address,
+		      &sctp_conn->sub_conn[i].connection.lcl_ip.ip6,
+		      clib_net_to_host_u16 (sctp_conn->sub_conn[i].
+					    connection.lcl_port),
+		      format_ip6_address,
+		      &sctp_conn->sub_conn[i].connection.rmt_ip.ip6,
+		      clib_net_to_host_u16 (sctp_conn->sub_conn[i].
+					    connection.rmt_port));
+	}
+    }
+  return s;
+}
+
+u8 *
+format_sctp_connection (u8 * s, va_list * args)
+{
+  sctp_connection_t *sctp_conn = va_arg (*args, sctp_connection_t *);
+  u32 verbose = va_arg (*args, u32);
+
+  if (!sctp_conn)
+    return s;
+  s = format (s, "%-50U", format_sctp_connection_id, sctp_conn);
+  if (verbose)
+    {
+      s = format (s, "%-15U", format_sctp_state, sctp_conn->state);
+      if (verbose > 1)
+	s = format (s, "\n");
+    }
+
+  return s;
+}
+
+/**
+ * Initialize connection send variables.
+ */
+void
+sctp_init_snd_vars (sctp_connection_t * sctp_conn)
+{
+  u32 time_now;
+  /*
+   * We use the time to randomize iss and for setting up the initial
+   * timestamp. Make sure it's updated otherwise syn and ack in the
+   * handshake may make it look as if time has flown in the opposite
+   * direction for us.
+   */
+
+  sctp_set_time_now (vlib_get_thread_index ());
+  time_now = sctp_time_now ();
+
+  sctp_conn->local_initial_tsn = random_u32 (&time_now);
+  sctp_conn->last_unacked_tsn = sctp_conn->local_initial_tsn;
+  sctp_conn->next_tsn = sctp_conn->local_initial_tsn + 1;
+
+  sctp_conn->remote_initial_tsn = 0x0;
+  sctp_conn->last_rcvd_tsn = sctp_conn->remote_initial_tsn;
+}
+
+always_inline sctp_connection_t *
+sctp_sub_connection_add (u8 thread_index)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  sctp_connection_t *sctp_conn = tm->connections[thread_index];
+
+  u8 subconn_idx = sctp_next_avail_subconn (sctp_conn);
+
+  ASSERT (subconn_idx < MAX_SCTP_CONNECTIONS);
+
+  sctp_conn->sub_conn[subconn_idx].connection.c_index =
+    sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.c_index;
+  sctp_conn->sub_conn[subconn_idx].connection.thread_index = thread_index;
+  sctp_conn->sub_conn[subconn_idx].subconn_idx = subconn_idx;
+
+  return sctp_conn;
+}
+
+u8
+sctp_sub_connection_add_ip4 (vlib_main_t * vm,
+			     ip4_address_t * lcl_addr,
+			     ip4_address_t * rmt_addr)
+{
+  sctp_connection_t *sctp_conn = sctp_sub_connection_add (vm->thread_index);
+
+  u8 subconn_idx = sctp_next_avail_subconn (sctp_conn);
+
+  if (subconn_idx == MAX_SCTP_CONNECTIONS)
+    return SCTP_ERROR_MAX_CONNECTIONS;
+
+  clib_memcpy (&sctp_conn->sub_conn[subconn_idx].connection.lcl_ip,
+	       &lcl_addr, sizeof (lcl_addr));
+
+  clib_memcpy (&sctp_conn->sub_conn[subconn_idx].connection.rmt_ip,
+	       &rmt_addr, sizeof (rmt_addr));
+
+  sctp_conn->forming_association_changed = 1;
+
+  return SCTP_ERROR_NONE;
+}
+
+u8
+sctp_sub_connection_del_ip4 (ip4_address_t * lcl_addr,
+			     ip4_address_t * rmt_addr)
+{
+  sctp_main_t *sctp_main = vnet_get_sctp_main ();
+
+  u32 thread_idx = vlib_get_thread_index ();
+  u8 i;
+
+  ASSERT (thread_idx == 0);
+
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      sctp_connection_t *sctp_conn = sctp_main->connections[thread_idx];
+      sctp_sub_connection_t *sub_conn =
+	&sctp_main->connections[thread_idx]->sub_conn[i];
+      ip46_address_t *lcl_ip =
+	&sctp_main->connections[thread_idx]->sub_conn[i].connection.lcl_ip;
+      ip46_address_t *rmt_ip =
+	&sctp_main->connections[thread_idx]->sub_conn[i].connection.rmt_ip;
+
+      if (!sub_conn->connection.is_ip4)
+	continue;
+      if (lcl_ip->ip4.as_u32 == lcl_addr->as_u32 &&
+	  rmt_ip->ip4.as_u32 == rmt_addr->as_u32)
+	{
+	  sub_conn->state = SCTP_SUBCONN_STATE_DOWN;
+	  sctp_conn->forming_association_changed = 1;
+	  break;
+	}
+    }
+  return SCTP_ERROR_NONE;
+}
+
+u8
+sctp_sub_connection_add_ip6 (vlib_main_t * vm,
+			     ip6_address_t * lcl_addr,
+			     ip6_address_t * rmt_addr)
+{
+  sctp_connection_t *sctp_conn = sctp_sub_connection_add (vm->thread_index);
+
+  u8 subconn_idx = sctp_next_avail_subconn (sctp_conn);
+
+  if (subconn_idx == MAX_SCTP_CONNECTIONS)
+    return SCTP_ERROR_MAX_CONNECTIONS;
+
+  clib_memcpy (&sctp_conn->sub_conn[subconn_idx].connection.lcl_ip,
+	       &lcl_addr, sizeof (lcl_addr));
+
+  clib_memcpy (&sctp_conn->sub_conn[subconn_idx].connection.rmt_ip,
+	       &rmt_addr, sizeof (rmt_addr));
+
+  sctp_conn->forming_association_changed = 1;
+
+  return SCTP_ERROR_NONE;
+}
+
+u8
+sctp_sub_connection_del_ip6 (ip6_address_t * lcl_addr,
+			     ip6_address_t * rmt_addr)
+{
+  sctp_main_t *sctp_main = vnet_get_sctp_main ();
+
+  u32 thread_idx = vlib_get_thread_index ();
+  u8 i;
+
+  ASSERT (thread_idx == 0);
+
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      sctp_connection_t *sctp_conn = sctp_main->connections[thread_idx];
+      sctp_sub_connection_t *sub_conn =
+	&sctp_main->connections[thread_idx]->sub_conn[i];
+      ip46_address_t *lcl_ip =
+	&sctp_main->connections[thread_idx]->sub_conn[i].connection.lcl_ip;
+      ip46_address_t *rmt_ip =
+	&sctp_main->connections[thread_idx]->sub_conn[i].connection.rmt_ip;
+
+      if (!sub_conn->connection.is_ip4)
+	continue;
+      if ((lcl_ip->ip6.as_u64[0] == lcl_addr->as_u64[0]
+	   && lcl_ip->ip6.as_u64[1] == lcl_addr->as_u64[1])
+	  && (rmt_ip->ip6.as_u64[0] == rmt_addr->as_u64[0]
+	      && rmt_ip->ip6.as_u64[1] == rmt_addr->as_u64[1]))
+	{
+	  sub_conn->state = SCTP_SUBCONN_STATE_DOWN;
+	  sctp_conn->forming_association_changed = 1;
+	  break;
+	}
+    }
+  return SCTP_ERROR_NONE;
+}
+
+u8
+sctp_configure (sctp_user_configuration_t config)
+{
+  sctp_main_t *sctp_main = vnet_get_sctp_main ();
+
+  u32 thread_idx = vlib_get_thread_index ();
+
+  sctp_main->connections[thread_idx]->conn_config.never_delay_sack =
+    config.never_delay_sack;
+  sctp_main->connections[thread_idx]->conn_config.never_bundle =
+    config.never_bundle;
+
+  return 0;
+}
+
+sctp_connection_t *
+sctp_connection_new (u8 thread_index)
+{
+  sctp_main_t *sctp_main = vnet_get_sctp_main ();
+  sctp_connection_t *sctp_conn;
+
+  pool_get (sctp_main->connections[thread_index], sctp_conn);
+  clib_memset (sctp_conn, 0, sizeof (*sctp_conn));
+  sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].subconn_idx =
+    SCTP_PRIMARY_PATH_IDX;
+  sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_c_index =
+    sctp_conn - sctp_main->connections[thread_index];
+  sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_thread_index = thread_index;
+  sctp_conn->local_tag = 0;
+
+  return sctp_conn;
+}
+
+sctp_connection_t *
+sctp_half_open_connection_new (u8 thread_index)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  sctp_connection_t *sctp_conn = 0;
+  ASSERT (vlib_get_thread_index () == 0);
+  pool_get (tm->half_open_connections, sctp_conn);
+  clib_memset (sctp_conn, 0, sizeof (*sctp_conn));
+  sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_c_index =
+    sctp_conn - tm->half_open_connections;
+  sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].subconn_idx =
+    SCTP_PRIMARY_PATH_IDX;
+  return sctp_conn;
+}
+
+static inline int
+sctp_connection_open (transport_endpoint_cfg_t * rmt)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  sctp_connection_t *sctp_conn;
+  ip46_address_t lcl_addr;
+  u16 lcl_port;
+  uword thread_id;
+  u32 mtu = 1460;
+  int rv;
+
+  u8 idx = SCTP_PRIMARY_PATH_IDX;
+
+  /*
+   * Allocate local endpoint
+   */
+  if ((rmt->is_ip4 && vec_len (tm->ip4_src_addresses))
+      || (!rmt->is_ip4 && vec_len (tm->ip6_src_addresses)))
+    rv = sctp_alloc_custom_local_endpoint (tm, &lcl_addr, &lcl_port,
+					   rmt->is_ip4);
+  else
+    rv = transport_alloc_local_endpoint (TRANSPORT_PROTO_SCTP,
+					 rmt, &lcl_addr, &lcl_port);
+
+  if (rv)
+    return -1;
+
+  /*
+   * Create connection and send INIT CHUNK
+   */
+  thread_id = vlib_get_thread_index ();
+  ASSERT (thread_id == 0);
+
+  clib_spinlock_lock_if_init (&tm->half_open_lock);
+  sctp_conn = sctp_half_open_connection_new (thread_id);
+  if (rmt->peer.sw_if_index != ENDPOINT_INVALID_INDEX)
+    mtu = rmt->is_ip4 ? vnet_sw_interface_get_mtu (vnet_get_main (),
+						   rmt->peer.sw_if_index,
+						   VNET_MTU_IP4) :
+      vnet_sw_interface_get_mtu (vnet_get_main (), rmt->peer.sw_if_index,
+				 VNET_MTU_IP6);
+  sctp_conn->sub_conn[idx].PMTU = mtu;
+
+  transport_connection_t *trans_conn = &sctp_conn->sub_conn[idx].connection;
+  ip_copy (&trans_conn->rmt_ip, &rmt->ip, rmt->is_ip4);
+  ip_copy (&trans_conn->lcl_ip, &lcl_addr, rmt->is_ip4);
+  sctp_conn->sub_conn[idx].subconn_idx = idx;
+  trans_conn->rmt_port = rmt->port;
+  trans_conn->lcl_port = clib_host_to_net_u16 (lcl_port);
+  trans_conn->is_ip4 = rmt->is_ip4;
+  trans_conn->proto = TRANSPORT_PROTO_SCTP;
+  trans_conn->fib_index = rmt->fib_index;
+
+  sctp_connection_timers_init (sctp_conn);
+  /* The other connection vars will be initialized after INIT_ACK chunk received */
+  sctp_init_snd_vars (sctp_conn);
+
+  sctp_send_init (sctp_conn);
+
+  clib_spinlock_unlock_if_init (&tm->half_open_lock);
+
+  return sctp_conn->sub_conn[idx].connection.c_index;
+}
+
+/**
+ * Cleans up connection state.
+ *
+ * No notifications.
+ */
+void
+sctp_connection_cleanup (sctp_connection_t * sctp_conn)
+{
+  sctp_main_t *tm = &sctp_main;
+  u8 i;
+
+  /* Cleanup local endpoint if this was an active connect */
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    transport_endpoint_cleanup (TRANSPORT_PROTO_SCTP,
+				&sctp_conn->sub_conn[i].connection.lcl_ip,
+				sctp_conn->sub_conn[i].connection.lcl_port);
+
+  int thread_index =
+    sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.thread_index;
+
+  /* Make sure all timers are cleared */
+  sctp_connection_timers_reset (sctp_conn);
+
+  /* Poison the entry */
+  if (CLIB_DEBUG > 0)
+    clib_memset (sctp_conn, 0xFA, sizeof (*sctp_conn));
+  pool_put (tm->connections[thread_index], sctp_conn);
+}
+
+int
+sctp_session_open (transport_endpoint_cfg_t * tep)
+{
+  return sctp_connection_open (tep);
+}
+
+u16
+sctp_check_outstanding_data_chunks (sctp_connection_t * sctp_conn)
+{
+  u8 i;
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      if (sctp_conn->sub_conn[i].state == SCTP_SUBCONN_STATE_DOWN)
+	continue;
+
+      if (sctp_conn->sub_conn[i].is_retransmitting == 1 ||
+	  sctp_conn->sub_conn[i].enqueue_state != SCTP_ERROR_ENQUEUED)
+	{
+	  SCTP_DBG_OUTPUT
+	    ("Connection %u has still DATA to be enqueued inboud / outboud",
+	     sctp_conn->sub_conn[i].connection.c_index);
+	  return 1;
+	}
+
+    }
+  return 0;			/* Indicates no more data to be read/sent */
+}
+
+void
+sctp_connection_close (sctp_connection_t * sctp_conn)
+{
+  SCTP_DBG ("Closing connection %u...",
+	    sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.c_index);
+
+  sctp_conn->state = SCTP_STATE_SHUTDOWN_PENDING;
+
+  sctp_send_shutdown (sctp_conn);
+}
+
+void
+sctp_session_close (u32 conn_index, u32 thread_index)
+{
+  ASSERT (thread_index == 0);
+
+  sctp_connection_t *sctp_conn =
+    sctp_connection_get (conn_index, thread_index);
+  if (sctp_conn != NULL)
+    sctp_connection_close (sctp_conn);
+}
+
+void
+sctp_session_cleanup (u32 conn_index, u32 thread_index)
+{
+  sctp_connection_t *sctp_conn =
+    sctp_connection_get (conn_index, thread_index);
+
+  if (sctp_conn != NULL)
+    {
+      sctp_connection_timers_reset (sctp_conn);
+      /* Wait for the session tx events to clear */
+      sctp_conn->state = SCTP_STATE_CLOSED;
+    }
+}
+
+/**
+ * Compute maximum segment size for session layer.
+ */
+u16
+sctp_session_send_mss (transport_connection_t * trans_conn)
+{
+  sctp_connection_t *sctp_conn =
+    sctp_get_connection_from_transport (trans_conn);
+
+  if (sctp_conn == NULL)
+    {
+      SCTP_DBG ("sctp_conn == NULL");
+      return 0;
+    }
+
+  update_cwnd (sctp_conn);
+  update_smallest_pmtu_idx (sctp_conn);
+
+  u8 idx = sctp_data_subconn_select (sctp_conn);
+  return sctp_conn->sub_conn[idx].cwnd;
+}
+
+u16
+sctp_snd_space (sctp_connection_t * sctp_conn)
+{
+  /* RFC 4096 Section 6.1; point (A) */
+  if (sctp_conn->peer_rwnd == 0)
+    return 0;
+
+  u8 idx = sctp_data_subconn_select (sctp_conn);
+
+  u32 available_wnd =
+    clib_min (sctp_conn->peer_rwnd, sctp_conn->sub_conn[idx].cwnd);
+  int flight_size = (int) (sctp_conn->next_tsn - sctp_conn->last_unacked_tsn);
+
+  if (available_wnd <= flight_size)
+    return 0;
+
+  /* Finally, let's subtract the DATA chunk headers overhead */
+  return available_wnd -
+    flight_size -
+    sizeof (sctp_payload_data_chunk_t) - sizeof (sctp_full_hdr_t);
+}
+
+/**
+ * Compute TX window session is allowed to fill.
+ */
+u32
+sctp_session_send_space (transport_connection_t * trans_conn)
+{
+  sctp_connection_t *sctp_conn =
+    sctp_get_connection_from_transport (trans_conn);
+
+  return sctp_snd_space (sctp_conn);
+}
+
+transport_connection_t *
+sctp_session_get_transport (u32 conn_index, u32 thread_index)
+{
+  sctp_connection_t *sctp_conn =
+    sctp_connection_get (conn_index, thread_index);
+
+  if (PREDICT_TRUE (sctp_conn != NULL))
+    return &sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection;
+
+  return NULL;
+}
+
+transport_connection_t *
+sctp_session_get_listener (u32 listener_index)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  sctp_connection_t *sctp_conn;
+  sctp_conn = pool_elt_at_index (tm->listener_pool, listener_index);
+  return &sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection;
+}
+
+u8 *
+format_sctp_session (u8 * s, va_list * args)
+{
+  u32 tci = va_arg (*args, u32);
+  u32 thread_index = va_arg (*args, u32);
+  u32 verbose = va_arg (*args, u32);
+  sctp_connection_t *tc;
+
+  tc = sctp_connection_get (tci, thread_index);
+  if (tc)
+    s = format (s, "%U", format_sctp_connection, tc, verbose);
+  else
+    s = format (s, "empty\n");
+  return s;
+}
+
+u8 *
+format_sctp_listener_session (u8 * s, va_list * args)
+{
+  u32 tci = va_arg (*args, u32);
+  sctp_connection_t *tc = sctp_listener_get (tci);
+  return format (s, "%U", format_sctp_connection_id, tc);
+}
+
+void
+sctp_expired_timers_cb (u32 conn_index, u32 timer_id)
+{
+  sctp_connection_t *sctp_conn;
+
+  SCTP_DBG ("%s expired", sctp_timer_to_string (timer_id));
+
+  sctp_conn = sctp_connection_get (conn_index, vlib_get_thread_index ());
+  /* note: the connection may have already disappeared */
+  if (PREDICT_FALSE (sctp_conn == 0))
+    return;
+
+  if (sctp_conn->sub_conn[conn_index].unacknowledged_hb >
+      SCTP_PATH_MAX_RETRANS)
+    {
+      // The remote-peer is considered to be unreachable hence shutting down
+      u8 i, total_subs_down = 1;
+      for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+	{
+	  if (sctp_conn->sub_conn[i].state == SCTP_SUBCONN_STATE_DOWN)
+	    continue;
+
+	  u32 now = sctp_time_now ();
+	  if (now > (sctp_conn->sub_conn[i].last_seen + SCTP_HB_INTERVAL))
+	    {
+	      total_subs_down += 1;
+	      sctp_conn->sub_conn[i].state = SCTP_SUBCONN_STATE_DOWN;
+	    }
+	}
+
+      if (total_subs_down == MAX_SCTP_CONNECTIONS)
+	{
+	  /* Start cleanup. App wasn't notified yet so use delete notify as
+	   * opposed to delete to cleanup session layer state. */
+	  session_transport_delete_notify (&sctp_conn->sub_conn
+					   [SCTP_PRIMARY_PATH_IDX].connection);
+
+	  sctp_connection_timers_reset (sctp_conn);
+
+	  sctp_connection_cleanup (sctp_conn);
+	}
+      return;
+    }
+
+  switch (timer_id)
+    {
+    case SCTP_TIMER_T1_INIT:
+      sctp_send_init (sctp_conn);
+      break;
+    case SCTP_TIMER_T1_COOKIE:
+      sctp_send_cookie_echo (sctp_conn);
+      break;
+    case SCTP_TIMER_T2_SHUTDOWN:
+      sctp_send_shutdown (sctp_conn);
+      break;
+    case SCTP_TIMER_T3_RXTX:
+      sctp_timer_reset (sctp_conn, conn_index, timer_id);
+      sctp_conn->flags |= SCTP_CONN_RECOVERY;
+      sctp_data_retransmit (sctp_conn);
+      break;
+    case SCTP_TIMER_T4_HEARTBEAT:
+      sctp_timer_reset (sctp_conn, conn_index, timer_id);
+      goto heartbeat;
+    }
+  return;
+
+heartbeat:
+  sctp_send_heartbeat (sctp_conn);
+}
+
+static void
+sctp_expired_timers_dispatch (u32 * expired_timers)
+{
+  int i;
+  u32 connection_index, timer_id;
+
+  for (i = 0; i < vec_len (expired_timers); i++)
+    {
+      /* Get session index and timer id */
+      connection_index = expired_timers[i] & 0x0FFFFFFF;
+      timer_id = expired_timers[i] >> 28;
+
+      SCTP_DBG ("Expired timer ID: %u", timer_id);
+
+      /* Handle expiration */
+      sctp_expired_timers_cb (connection_index, timer_id);
+    }
+}
+
+void
+sctp_initialize_timer_wheels (sctp_main_t * tm)
+{
+  tw_timer_wheel_16t_2w_512sl_t *tw;
+  /* *INDENT-OFF* */
+  foreach_vlib_main (({
+    tw = &tm->timer_wheels[ii];
+    tw_timer_wheel_init_16t_2w_512sl (tw, sctp_expired_timers_dispatch,
+				      100e-3 /* timer period 100ms */ , ~0);
+    tw->last_run_time = vlib_time_now (this_vlib_main);
+  }));
+  /* *INDENT-ON* */
+}
+
+clib_error_t *
+sctp_main_enable (vlib_main_t * vm)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  vlib_thread_main_t *vtm = vlib_get_thread_main ();
+  clib_error_t *error = 0;
+  u32 num_threads;
+  int thread;
+  sctp_connection_t *sctp_conn __attribute__ ((unused));
+  u32 preallocated_connections_per_thread;
+
+  if ((error = vlib_call_init_function (vm, ip_main_init)))
+    return error;
+  if ((error = vlib_call_init_function (vm, ip4_lookup_init)))
+    return error;
+  if ((error = vlib_call_init_function (vm, ip6_lookup_init)))
+    return error;
+
+  /*
+   * Registrations
+   */
+
+  ip4_register_protocol (IP_PROTOCOL_SCTP, sctp4_input_node.index);
+  ip6_register_protocol (IP_PROTOCOL_SCTP, sctp6_input_node.index);
+
+  /*
+   * Initialize data structures
+   */
+
+  num_threads = 1 /* main thread */  + vtm->n_threads;
+  vec_validate (tm->connections, num_threads - 1);
+
+  /*
+   * Preallocate connections. Assume that thread 0 won't
+   * use preallocated threads when running multi-core
+   */
+  if (num_threads == 1)
+    {
+      thread = 0;
+      preallocated_connections_per_thread = tm->preallocated_connections;
+    }
+  else
+    {
+      thread = 1;
+      preallocated_connections_per_thread =
+	tm->preallocated_connections / (num_threads - 1);
+    }
+  for (; thread < num_threads; thread++)
+    {
+      if (preallocated_connections_per_thread)
+	pool_init_fixed (tm->connections[thread],
+			 preallocated_connections_per_thread);
+    }
+
+  /* Initialize per worker thread tx buffers (used for control messages) */
+  vec_validate (tm->tx_buffers, num_threads - 1);
+
+  /* Initialize timer wheels */
+  vec_validate (tm->timer_wheels, num_threads - 1);
+  sctp_initialize_timer_wheels (tm);
+
+  /* Initialize clocks per tick for SCTP timestamp. Used to compute
+   * monotonically increasing timestamps. */
+  tm->tstamp_ticks_per_clock = vm->clib_time.seconds_per_clock
+    / SCTP_TSTAMP_RESOLUTION;
+
+  if (num_threads > 1)
+    {
+      clib_spinlock_init (&tm->half_open_lock);
+    }
+
+  vec_validate (tm->tx_frames[0], num_threads - 1);
+  vec_validate (tm->tx_frames[1], num_threads - 1);
+  vec_validate (tm->ip_lookup_tx_frames[0], num_threads - 1);
+  vec_validate (tm->ip_lookup_tx_frames[1], num_threads - 1);
+
+  tm->bytes_per_buffer = vlib_buffer_get_default_data_size (vm);
+
+  vec_validate (tm->time_now, num_threads - 1);
+  return error;
+}
+
+clib_error_t *
+sctp_transport_enable_disable (vlib_main_t * vm, u8 is_en)
+{
+  if (is_en)
+    {
+      if (sctp_main.is_enabled)
+	return 0;
+
+      return sctp_main_enable (vm);
+    }
+  else
+    {
+      sctp_main.is_enabled = 0;
+    }
+
+  return 0;
+}
+
+transport_connection_t *
+sctp_half_open_session_get_transport (u32 conn_index)
+{
+  sctp_connection_t *sctp_conn = sctp_half_open_connection_get (conn_index);
+  return &sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection;
+}
+
+u8 *
+format_sctp_half_open (u8 * s, va_list * args)
+{
+  u32 tci = va_arg (*args, u32);
+  sctp_connection_t *sctp_conn = sctp_half_open_connection_get (tci);
+  return format (s, "%U", format_sctp_connection_id, sctp_conn);
+}
+
+void
+sctp_update_time (f64 now, u8 thread_index)
+{
+  sctp_set_time_now (thread_index);
+  tw_timer_expire_timers_16t_2w_512sl (&sctp_main.timer_wheels[thread_index],
+				       now);
+  sctp_flush_frames_to_output (thread_index);
+}
+
+/* *INDENT-OFF* */
+static const transport_proto_vft_t sctp_proto = {
+  .enable = sctp_transport_enable_disable,
+  .start_listen = sctp_session_bind,
+  .stop_listen = sctp_session_unbind,
+  .connect = sctp_session_open,
+  .close = sctp_session_close,
+  .cleanup = sctp_session_cleanup,
+  .push_header = sctp_push_header,
+  .send_mss = sctp_session_send_mss,
+  .send_space = sctp_session_send_space,
+  .update_time = sctp_update_time,
+  .get_connection = sctp_session_get_transport,
+  .get_listener = sctp_session_get_listener,
+  .get_half_open = sctp_half_open_session_get_transport,
+  .format_connection = format_sctp_session,
+  .format_listener = format_sctp_listener_session,
+  .format_half_open = format_sctp_half_open,
+  .transport_options = {
+    .tx_type = TRANSPORT_TX_DEQUEUE,
+    .service_type = TRANSPORT_SERVICE_VC,
+  },
+};
+/* *INDENT-ON* */
+
+clib_error_t *
+sctp_enable_disable (vlib_main_t * vm, u8 is_en)
+{
+  sctp_main_t *sm = vnet_get_sctp_main ();
+  ip_main_t *im = &ip_main;
+  ip_protocol_info_t *pi;
+  vlib_node_t *node;
+
+  if (!sm->is_init && is_en)
+    {
+      node = vlib_get_node_by_name (vm, (u8 *) "sctp4-established");
+      sm->sctp4_established_phase_node_index = node->index;
+
+      node = vlib_get_node_by_name (vm, (u8 *) "sctp6-established");
+      sm->sctp6_established_phase_node_index = node->index;
+
+      sm->is_init = 1;
+
+      /* Register with IP for header parsing */
+      pi = ip_get_protocol_info (im, IP_PROTOCOL_SCTP);
+      if (pi == 0)
+	return clib_error_return (0, "SCTP protocol info AWOL");
+      pi->format_header = format_sctp_header;
+      pi->unformat_pg_edit = unformat_pg_sctp_header;
+
+      /* Register as transport with session layer */
+      transport_register_protocol (TRANSPORT_PROTO_SCTP, &sctp_proto,
+				   FIB_PROTOCOL_IP4, sctp4_output_node.index);
+      transport_register_protocol (TRANSPORT_PROTO_SCTP, &sctp_proto,
+				   FIB_PROTOCOL_IP6, sctp6_output_node.index);
+    }
+
+  sctp_transport_enable_disable (vm, is_en);
+  return 0;
+}
+
+static u8 *
+sctp_format_buffer_opaque_helper (const vlib_buffer_t * b, u8 * s)
+{
+  sctp_buffer_opaque_t *o = sctp_buffer_opaque (b);
+
+  s = format (s,
+	      "sctp.connection_index: %d, sctp.sid: %d, sctp.ssn: %d, "
+	      "sctp.tsn: %d, sctp.hdr_offset: %d",
+	      o->sctp.connection_index,
+	      (u32) (o->sctp.sid),
+	      (u32) (o->sctp.ssn),
+	      (u32) (o->sctp.tsn), (u32) (o->sctp.hdr_offset));
+  vec_add1 (s, '\n');
+
+  s = format
+    (s, "sctp.data_offset: %d, sctp.data_len: %d, sctp.subconn_idx: %d, "
+     "sctp.flags: 0x%x",
+     (u32) (o->sctp.data_offset),
+     (u32) (o->sctp.data_len),
+     (u32) (o->sctp.subconn_idx), (u32) (o->sctp.flags));
+  vec_add1 (s, '\n');
+  return s;
+}
+
+clib_error_t *
+sctp_init (vlib_main_t * vm)
+{
+  sctp_main_t *sm = vnet_get_sctp_main ();
+
+  /* Session layer, and by implication SCTP, are disabled by default */
+  sm->is_enabled = 0;
+  sm->is_init = 0;
+
+  /* initialize binary API */
+  sctp_plugin_api_hookup (vm);
+
+  vnet_register_format_buffer_opaque_helper
+    (sctp_format_buffer_opaque_helper);
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (sctp_init);
+
+static clib_error_t *
+show_sctp_punt_fn (vlib_main_t * vm, unformat_input_t * input,
+		   vlib_cli_command_t * cmd_arg)
+{
+  sctp_main_t *tm = &sctp_main;
+  if (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    return clib_error_return (0, "unknown input `%U'", format_unformat_error,
+			      input);
+  vlib_cli_output (vm, "IPv4 UDP punt: %s",
+		   tm->punt_unknown4 ? "enabled" : "disabled");
+  vlib_cli_output (vm, "IPv6 UDP punt: %s",
+		   tm->punt_unknown6 ? "enabled" : "disabled");
+  return 0;
+}
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (show_tcp_punt_command, static) =
+{
+  .path = "show sctp punt",
+  .short_help = "show sctp punt",
+  .function = show_sctp_punt_fn,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+sctp_fn (vlib_main_t * vm, unformat_input_t * input,
+	 vlib_cli_command_t * cmd_arg)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+  clib_error_t *error;
+  u8 is_en;
+
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return clib_error_return (0, "expected enable | disable");
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "enable"))
+	is_en = 1;
+      else if (unformat (line_input, "disable"))
+	is_en = 0;
+      else
+	{
+	  error = clib_error_return (0, "unknown input `%U'",
+				     format_unformat_error, line_input);
+	  unformat_free (line_input);
+	  return error;
+	}
+    }
+
+  unformat_free (line_input);
+
+  return sctp_enable_disable (vm, is_en);
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (show_sctp_command, static) =
+{
+  .path = "sctp",
+  .short_help = "sctp [enable | disable]",
+  .function = sctp_fn,
+};
+
+/* *INDENT-OFF* */
+VLIB_PLUGIN_REGISTER () =
+{
+  .version = VPP_BUILD_VER,
+  .description = "Stream Control Transmission Protocol (SCTP)",
+  .default_disabled = 1,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp.h b/src/plugins/sctp/sctp.h
new file mode 100644
index 00000000000..a99b01c1c0a
--- /dev/null
+++ b/src/plugins/sctp/sctp.h
@@ -0,0 +1,1019 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_vnet_sctp_h
+#define included_vnet_sctp_h
+
+#include <vnet/vnet.h>
+#include <vnet/ip/ip.h>
+#include <sctp/sctp_timer.h>
+#include <sctp/sctp_packet.h>
+#include <vnet/session/transport.h>
+#include <vnet/session/session.h>
+
+/* SCTP buffer opaque definition */
+typedef struct
+{
+  struct
+  {
+    u32 connection_index;
+    u16 sid; /**< Stream ID */
+    u16 ssn; /**< Stream Sequence Number */
+    u32 tsn; /**< Transmission Sequence Number */
+    u16 hdr_offset;		/**< offset relative to ip hdr */
+    u16 data_offset;		/**< offset relative to ip hdr */
+    u16 data_len;		/**< data len */
+    u8 subconn_idx; /**< index of the sub_connection being used */
+    u8 flags;
+  } sctp;
+} sctp_buffer_opaque_t;
+
+STATIC_ASSERT (sizeof (sctp_buffer_opaque_t) <=
+	       STRUCT_SIZE_OF (vnet_buffer_opaque_t, unused),
+	       "sctp_buffer_opaque_t too large for vnet_buffer_opaque_t");
+
+#define sctp_buffer_opaque(b)                           \
+  ((sctp_buffer_opaque_t *)((u8 *)((b)->opaque) +       \
+STRUCT_OFFSET_OF (vnet_buffer_opaque_t, unused)))
+
+
+/* SCTP timers */
+#define foreach_sctp_timer              	\
+  _(T1_INIT, "T1_INIT")                         \
+  _(T1_COOKIE, "T1_COOKIE")                     \
+  _(T2_SHUTDOWN, "T2_SHUTDOWN")         	\
+  _(T3_RXTX, "T3_RXTX")                         \
+  _(T4_HEARTBEAT, "T4_HB")                      \
+  _(T5_SHUTDOWN_GUARD, "T5_SHUTDOWN_GUARD")
+
+typedef enum _sctp_timers
+{
+#define _(sym, str) SCTP_TIMER_##sym,
+  foreach_sctp_timer
+#undef _
+  SCTP_N_TIMERS
+} sctp_timers_e;
+
+#define SCTP_TIMER_HANDLE_INVALID ((u32) ~0)
+
+always_inline char *
+sctp_timer_to_string (u8 timer_id)
+{
+  switch (timer_id)
+    {
+    case SCTP_TIMER_T1_INIT:
+      return "SCTP_TIMER_T1_INIT";
+    case SCTP_TIMER_T1_COOKIE:
+      return "SCTP_TIMER_T1_COOKIE";
+    case SCTP_TIMER_T2_SHUTDOWN:
+      return "SCTP_TIMER_T2_SHUTDOWN";
+    case SCTP_TIMER_T3_RXTX:
+      return "SCTP_TIMER_T3_RXTX";
+    case SCTP_TIMER_T4_HEARTBEAT:
+      return "SCTP_TIMER_T4_HEARTBEAT";
+    case SCTP_TIMER_T5_SHUTDOWN_GUARD:
+      return "SCTP_TIMER_T5_SHUTDOWN_GUARD";
+    }
+  return NULL;
+}
+
+typedef enum _sctp_error
+{
+#define sctp_error(n,s) SCTP_ERROR_##n,
+#include <sctp/sctp_error.def>
+#undef sctp_error
+  SCTP_N_ERROR,
+} sctp_error_t;
+
+#define NO_FLAG 0
+
+#define IS_T_BIT_SET(var) ((var) & (1))
+#define IS_E_BIT_SET(var) ((var) & (1))
+#define IS_B_BIT_SET(var) ((var) & (1<<1))
+#define IS_U_BIT_SET(var) ((var) & (1<<2))
+
+#define MAX_SCTP_CONNECTIONS 8
+#define SCTP_PRIMARY_PATH_IDX 0
+
+#if (VLIB_BUFFER_TRACE_TRAJECTORY)
+#define sctp_trajectory_add_start(b, start)			\
+{								\
+    (*vlib_buffer_trace_trajectory_cb) (b, start);		\
+}
+#else
+#define sctp_trajectory_add_start(b, start)
+#endif
+
+enum _sctp_subconn_state
+{
+  SCTP_SUBCONN_STATE_DOWN = 0,
+  SCTP_SUBCONN_STATE_UP,
+  SCTP_SUBCONN_STATE_ALLOW_HB,
+  SCTP_SUBCONN_AWAITING_SACK,
+  SCTP_SUBCONN_SACK_RECEIVED
+};
+
+#define SCTP_INITIAL_SSHTRESH 65535
+typedef struct _sctp_sub_connection
+{
+  transport_connection_t connection;	      /**< Common transport data. First! */
+
+  u8 subconn_idx; /**< This indicates the position of this sub-connection in the super-set container of connections pool */
+  u32 error_count; /**< The current error count for this destination. */
+  u32 error_threshold; /**< Current error threshold for this destination,
+				i.e. what value marks the destination down if error count reaches this value. */
+  u32 cwnd; /**< Congestion control window (cwnd, in bytes), which is adjusted by
+      the sender based on observed network conditions. */
+  u32 ssthresh;	/**< Slow-start threshold (in bytes), which is used by the
+      sender to distinguish slow-start and congestion avoidance phases. */
+
+  u64 rtt_ts;	/**< USED to hold the timestamp of when the packet has been sent */
+
+  u32 RTO; /**< The current retransmission timeout value. */
+  u64 SRTT; /**< The current smoothed round-trip time. */
+  f64 RTTVAR; /**< The current RTT variation. */
+
+  u32 partially_acked_bytes; /**< The tracking method for increase of cwnd when in
+  	  	  	  	  congestion avoidance mode (see Section 7.2.2).*/
+
+  u8 state; /**< The current state of this destination, i.e., DOWN, UP, ALLOW-HB, NO-HEARTBEAT, etc. */
+
+  u16 PMTU; /**< The current known path MTU. */
+
+  u32 timers[SCTP_N_TIMERS]; /**< A timer used by each destination. */
+
+  u8 RTO_pending; /**< A flag used to track if one of the DATA chunks sent to
+  	  	  	  	  this address is currently being used to compute an RTT.
+  	  	  	  	  If this flag is 0, the next DATA chunk sent to this destination
+  	  	  	  	  should be used to compute an RTT and this flag should be set.
+  	  	  	  	  Every time the RTT calculation completes (i.e., the DATA chunk is SACK'd),
+  	  	  	  	  clear this flag. */
+
+  u64 last_seen; /**< The time to which this destination was last sent a packet to.
+  	  	  	  	  This can be used to determine if a HEARTBEAT is needed. */
+
+  u64 last_data_ts; /**< Used to hold the timestamp value of last time we sent a DATA chunk */
+
+  u8 unacknowledged_hb;	/**< Used to track how many unacknowledged heartbeats we had;
+  	  	  	  	  If more than SCTP_PATH_MAX_RETRANS then connection is considered unreachable. */
+
+  u8 is_retransmitting;	/**< A flag (0 = no, 1 = yes) indicating whether the connection is retransmitting a previous packet */
+
+  u8 enqueue_state; /**< if set to 1 indicates that DATA is still being handled hence cannot shutdown this connection yet */
+
+} sctp_sub_connection_t;
+
+typedef struct
+{
+  u32 a_rwnd; /**< Maximum segment size advertised */
+
+} sctp_options_t;
+
+/* Useful macros to deal with the out_of_order_map (array of bit) */
+#define SET_BIT(A,k)     ( A[(k/32)] |= (1 << (k%32)) )
+#define CLEAR_BIT(A,k)   ( A[(k/32)] &= ~(1 << (k%32)) )
+#define TEST_BIT(A,k)    ( A[(k/32)] & (1 << (k%32)) )
+
+always_inline void
+_bytes_swap (void *pv, size_t n)
+{
+  char *p = pv;
+  size_t lo, hi;
+  for (lo = 0, hi = n - 1; hi > lo; lo++, hi--)
+    {
+      char tmp = p[lo];
+      p[lo] = p[hi];
+      p[hi] = tmp;
+    }
+}
+
+#define ENDIANESS_SWAP(x) _bytes_swap(&x, sizeof(x));
+
+#define MAX_INFLIGHT_PACKETS	128
+#define MAX_ENQUEABLE_SACKS 2
+
+/* This parameter indicates to the receiver how much increment in
+ * milliseconds the sender wishes the receiver to add to its default
+ * cookie life-span.
+ */
+#define SUGGESTED_COOKIE_LIFE_SPAN_INCREMENT 1000
+
+typedef struct _sctp_user_configuration
+{
+  u8 never_delay_sack;
+  u8 never_bundle;
+
+} sctp_user_configuration_t;
+
+typedef struct _sctp_connection
+{
+  /** Required for pool_get_aligned */
+  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
+
+  sctp_sub_connection_t sub_conn[MAX_SCTP_CONNECTIONS];	/**< Common transport data. First! */
+  sctp_user_configuration_t conn_config; /**< Allows tuning of some SCTP behaviors */
+
+  u8 state;			/**< SCTP state as per sctp_state_t */
+  u16 flags;		/**< Chunk flag (see sctp_chunks_common_hdr_t) */
+
+  u32 local_tag;	/**< INIT_TAG generated locally */
+  u32 remote_tag;	/**< INIT_TAG generated by the remote peer */
+
+  u32 local_initial_tsn; /**< Initial TSN generated locally */
+  u32 remote_initial_tsn; /**< Initial TSN generated by the remote-peer */
+
+  u32 peer_cookie_life_span_increment;
+
+  u32 overall_err_count; /**< The overall association error count. */
+  u32 overall_err_treshold; /**< The threshold for this association that if the Overall Error Count
+  	  	  	  	  reaches will cause this association to be torn down. */
+
+  u8 init_retransmit_err; /**< Error counter for the INIT transmission phase */
+
+  u32 peer_rwnd; /**< Current calculated value of the peer's rwnd. */
+
+  u32 next_tsn;	/**< The next TSN number to be assigned to a new DATA chunk.
+                 This is sent in the INIT or INIT ACK chunk to the peer
+                 and incremented each time a DATA chunk is assigned a
+                 TSN (normally just prior to transmit or during
+                 fragmentation). */
+
+  u32 last_unacked_tsn;	/** < Last TSN number still unacked */
+  u32 next_tsn_expected; /**< The next TSN number expected to be received. */
+
+  u32 last_rcvd_tsn; /**< This is the last TSN received in sequence. This value
+     	 	 	 is set initially by taking the peer's initial TSN,
+                 received in the INIT or INIT ACK chunk, and
+                 subtracting one from it. */
+
+  u32 out_of_order_map[MAX_INFLIGHT_PACKETS]; /**< An array of bits or bytes indicating which out-of-order
+				TSNs have been received (relative to the Last Rcvd TSN).
+				If no gaps exist, i.e., no out-of-order packets have been received,
+				this array will be set to all zero. */
+
+  u8 ack_state;	/**< This flag indicates if the next received packet is set to be responded to with a SACK.
+  	  	  	  	This is initialized to 0. When a packet is received it is incremented.
+  	  	  	  	If this value reaches 2 or more, a SACK is sent and the value is reset to 0.
+  	  	  	  	Note: This is used only when no DATA chunks are received out-of-order.
+  	  	  	  	When DATA chunks are out-of-order, SACKs are not delayed (see Section 6). */
+
+  u8 smallest_PMTU_idx;	/** The index of the sub-connection with the smallest PMTU discovered across all peer's transport addresses. */
+
+  u8 overall_sending_status; /**< 0 indicates first fragment of a user message
+  	  	  	  	  	  	  	  	  1 indicates normal stream
+  	  	  	  	  	  	  	  	  2 indicates last fragment of a user message */
+
+  u8 forming_association_changed; /**< This is a flag indicating whether the original association has been modified during
+  	  	  	  	  the life-span of the association itself. For instance, a new sub-connection might have been added. */
+
+  sctp_state_cookie_param_t cookie_param; /**< Temporary location to save cookie information; it can be used to
+  	  	  	  	  when timeout expires and sending again a COOKIE is require. */
+
+} sctp_connection_t;
+
+typedef void (sctp_timer_expiration_handler) (u32 conn_index, u32 timer_id);
+
+sctp_connection_t *sctp_connection_new (u8 thread_index);
+
+u8
+sctp_sub_connection_add_ip4 (vlib_main_t * vm,
+			     ip4_address_t * lcl_addr,
+			     ip4_address_t * rmt_addr);
+
+u8
+sctp_sub_connection_add_ip6 (vlib_main_t * vm,
+			     ip6_address_t * lcl_addr,
+			     ip6_address_t * rmt_addr);
+
+u8
+sctp_sub_connection_del_ip4 (ip4_address_t * lcl_addr,
+			     ip4_address_t * rmt_addr);
+
+u8
+sctp_sub_connection_del_ip6 (ip6_address_t * lcl_addr,
+			     ip6_address_t * rmt_addr);
+
+u8 sctp_configure (sctp_user_configuration_t config);
+
+void sctp_connection_close (sctp_connection_t * sctp_conn);
+void sctp_connection_cleanup (sctp_connection_t * sctp_conn);
+void sctp_connection_del (sctp_connection_t * sctp_conn);
+
+u32 sctp_push_header (transport_connection_t * tconn, vlib_buffer_t * b);
+void sctp_send_init (sctp_connection_t * sctp_conn);
+void sctp_send_cookie_echo (sctp_connection_t * sctp_conn);
+void sctp_send_shutdown (sctp_connection_t * sctp_conn);
+void sctp_send_shutdown_ack (sctp_connection_t * sctp_conn, u8 idx,
+			     vlib_buffer_t * b);
+void sctp_send_shutdown_complete (sctp_connection_t * sctp_conn, u8 idx,
+				  vlib_buffer_t * b0);
+void sctp_send_heartbeat (sctp_connection_t * sctp_conn);
+void sctp_data_retransmit (sctp_connection_t * sctp_conn);
+void sctp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index,
+				 u8 is_ip4);
+void sctp_flush_frames_to_output (u8 thread_index);
+void sctp_punt_unknown (vlib_main_t * vm, u8 is_ip4, u8 is_add);
+
+format_function_t format_sctp_state;
+
+u8 *format_sctp_connection_id (u8 * s, va_list * args);
+u8 *format_sctp_connection (u8 * s, va_list * args);
+u8 *format_sctp_scoreboard (u8 * s, va_list * args);
+u8 *format_sctp_header (u8 * s, va_list * args);
+u8 *format_sctp_tx_trace (u8 * s, va_list * args);
+unformat_function_t unformat_pg_sctp_header;
+
+clib_error_t *sctp_init (vlib_main_t * vm);
+void sctp_connection_timers_init (sctp_connection_t * sctp_conn);
+void sctp_connection_timers_reset (sctp_connection_t * sctp_conn);
+void sctp_init_snd_vars (sctp_connection_t * sctp_conn);
+void sctp_init_mss (sctp_connection_t * sctp_conn);
+
+void sctp_prepare_initack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+				 vlib_buffer_t * b, ip4_address_t * ip4_addr,
+				 u8 add_ip4, ip6_address_t * ip6_addr,
+				 u8 add_ip6);
+void sctp_prepare_initack_chunk_for_collision (sctp_connection_t * sctp_conn,
+					       u8 idx, vlib_buffer_t * b,
+					       ip4_address_t * ip4_addr,
+					       ip6_address_t * ip6_addr);
+void sctp_prepare_abort_for_collision (sctp_connection_t * sctp_conn, u8 idx,
+				       vlib_buffer_t * b,
+				       ip4_address_t * ip4_addr,
+				       ip6_address_t * ip6_addr);
+void sctp_prepare_operation_error (sctp_connection_t * sctp_conn, u8 idx,
+				   vlib_buffer_t * b, u8 err_cause);
+void sctp_prepare_cookie_echo_chunk (sctp_connection_t * sctp_conn, u8 idx,
+				     vlib_buffer_t * b, u8 reuse_buffer);
+void sctp_prepare_cookie_ack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+				    vlib_buffer_t * b);
+void sctp_prepare_sack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+			      vlib_buffer_t * b);
+void sctp_prepare_heartbeat_ack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+				       vlib_buffer_t * b);
+
+u16 sctp_check_outstanding_data_chunks (sctp_connection_t * sctp_conn);
+
+void sctp_api_reference (void);
+
+#define IP_PROTOCOL_SCTP	132
+
+/** SSCTP FSM state definitions as per RFC4960. */
+#define foreach_sctp_fsm_state                \
+  _(CLOSED, "CLOSED")                         \
+  _(COOKIE_WAIT, "COOKIE_WAIT")               \
+  _(COOKIE_ECHOED, "COOKIE_ECHOED")           \
+  _(ESTABLISHED, "ESTABLISHED")               \
+  _(SHUTDOWN_PENDING, "SHUTDOWN_PENDING")     \
+  _(SHUTDOWN_SENT, "SHUTDOWN_SENT")           \
+  _(SHUTDOWN_RECEIVED, "SHUTDOWN_RECEIVED")   \
+  _(SHUTDOWN_ACK_SENT, "SHUTDOWN_ACK_SENT")
+
+typedef enum _sctp_state
+{
+#define _(sym, str) SCTP_STATE_##sym,
+  foreach_sctp_fsm_state
+#undef _
+  SCTP_N_STATES
+} sctp_state_t;
+
+always_inline char *
+sctp_state_to_string (u8 state)
+{
+  switch (state)
+    {
+    case SCTP_STATE_CLOSED:
+      return "SCTP_STATE_CLOSED";
+    case SCTP_STATE_COOKIE_WAIT:
+      return "SCTP_STATE_COOKIE_WAIT";
+    case SCTP_STATE_COOKIE_ECHOED:
+      return "SCTP_STATE_COOKIE_ECHOED";
+    case SCTP_STATE_ESTABLISHED:
+      return "SCTP_STATE_ESTABLISHED";
+    case SCTP_STATE_SHUTDOWN_PENDING:
+      return "SCTP_STATE_SHUTDOWN_PENDING";
+    case SCTP_STATE_SHUTDOWN_SENT:
+      return "SCTP_STATE_SHUTDOWN_SENT";
+    case SCTP_STATE_SHUTDOWN_RECEIVED:
+      return "SCTP_STATE_SHUTDOWN_RECEIVED";
+    case SCTP_STATE_SHUTDOWN_ACK_SENT:
+      return "SCTP_STATE_SHUTDOWN_ACK_SENT";
+    }
+  return NULL;
+}
+
+always_inline char *
+sctp_chunk_to_string (u8 type)
+{
+  switch (type)
+    {
+    case DATA:
+      return "DATA";
+    case INIT:
+      return "INIT";
+    case INIT_ACK:
+      return "INIT_ACK";
+    case SACK:
+      return "SACK";
+    case HEARTBEAT:
+      return "HEARTBEAT";
+    case HEARTBEAT_ACK:
+      return "HEARTBEAT_ACK";
+    case ABORT:
+      return "ABORT";
+    case SHUTDOWN:
+      return "SHUTDOWN";
+    case SHUTDOWN_ACK:
+      return "SHUTDOWN_ACK";
+    case OPERATION_ERROR:
+      return "OPERATION_ERROR";
+    case COOKIE_ECHO:
+      return "COOKIE_ECHO";
+    case COOKIE_ACK:
+      return "COOKIE_ACK";
+    case ECNE:
+      return "ECNE";
+    case CWR:
+      return "CWR";
+    case SHUTDOWN_COMPLETE:
+      return "SHUTDOWN_COMPLETE";
+    }
+  return NULL;
+}
+
+always_inline char *
+sctp_optparam_type_to_string (u8 type)
+{
+  switch (type)
+    {
+    case SCTP_IPV4_ADDRESS_TYPE:
+      return "SCTP_IPV4_ADDRESS_TYPE";
+    case SCTP_IPV6_ADDRESS_TYPE:
+      return "SCTP_IPV6_ADDRESS_TYPE";
+    case SCTP_STATE_COOKIE_TYPE:
+      return "SCTP_STATE_COOKIE_TYPE";
+    case SCTP_UNRECOGNIZED_TYPE:
+      return "SCTP_UNRECOGNIZED_TYPE";
+    case SCTP_COOKIE_PRESERVATIVE_TYPE:
+      return "SCTP_COOKIE_PRESERVATIVE_TYPE";
+    case SCTP_HOSTNAME_ADDRESS_TYPE:
+      return "SCTP_HOSTNAME_ADDRESS_TYPE";
+    case SCTP_SUPPORTED_ADDRESS_TYPES:
+      return "SCTP_SUPPORTED_ADDRESS_TYPES";
+    }
+  return NULL;
+}
+
+#define SCTP_TICK 0.001			/**< SCTP tick period (s) */
+#define SHZ (u32) (1/SCTP_TICK)		/**< SCTP tick frequency */
+#define SCTP_TSTAMP_RESOLUTION SCTP_TICK	/**< Time stamp resolution */
+
+/* As per RFC4960, page 83 */
+#define SCTP_RTO_INIT 3 * SHZ	/* 3 seconds */
+#define SCTP_RTO_MIN 1 * SHZ	/* 1 second */
+#define SCTP_RTO_MAX 60 * SHZ	/* 60 seconds */
+#define SCTP_RTO_BURST 4
+#define SCTP_RTO_ALPHA 1/8
+#define SCTP_RTO_BETA 1/4
+#define SCTP_VALID_COOKIE_LIFE 60 * SHZ	/* 60 seconds */
+#define SCTP_ASSOCIATION_MAX_RETRANS 10	// the overall connection
+#define SCTP_PATH_MAX_RETRANS 5	// number of attempts per destination address
+#define SCTP_MAX_INIT_RETRANS 8	// number of attempts
+#define SCTP_HB_INTERVAL 30 * SHZ
+#define SCTP_HB_MAX_BURST 1
+#define SCTP_DATA_IDLE_INTERVAL 15 * SHZ	/* 15 seconds; the time-interval after which the connetion is considered IDLE */
+#define SCTP_TO_TIMER_TICK       SCTP_TICK*10	/* Period for converting from SCTP_TICK */
+
+#define SCTP_CONN_RECOVERY 1 << 1
+#define SCTP_FAST_RECOVERY 1 << 2
+
+typedef struct _sctp_lookup_dispatch
+{
+  u8 next, error;
+} sctp_lookup_dispatch_t;
+
+typedef struct _sctp_main
+{
+  /* Per-worker thread SCTP connection pools */
+  sctp_connection_t **connections;
+
+  /* Pool of listeners. */
+  sctp_connection_t *listener_pool;
+
+	  /** Dispatch table by state and flags */
+  sctp_lookup_dispatch_t dispatch_table[SCTP_N_STATES][64];
+
+  u8 log2_tstamp_clocks_per_tick;
+  f64 tstamp_ticks_per_clock;
+  u64 *time_now;
+
+	  /** per-worker tx buffer free lists */
+  u32 **tx_buffers;
+	  /** per-worker tx frames to SCTP 4/6 output nodes */
+  vlib_frame_t **tx_frames[2];
+	  /** per-worker tx frames to ip 4/6 lookup nodes */
+  vlib_frame_t **ip_lookup_tx_frames[2];
+
+  /* Per worker-thread timer wheel for connections timers */
+  tw_timer_wheel_16t_2w_512sl_t *timer_wheels;
+
+  /* Pool of half-open connections on which we've sent a SYN */
+  sctp_connection_t *half_open_connections;
+  clib_spinlock_t half_open_lock;
+
+  /* TODO: Congestion control algorithms registered */
+  /* sctp_cc_algorithm_t *cc_algos; */
+
+  /* Flag that indicates if stack is on or off */
+  u8 is_enabled;
+  u8 is_init;
+
+	  /** Number of preallocated connections */
+  u32 preallocated_connections;
+
+	  /** Transport table (preallocation) size parameters */
+  u32 local_endpoints_table_memory;
+  u32 local_endpoints_table_buckets;
+
+	  /** Vectors of src addresses. Optional unless one needs > 63K active-opens */
+  ip4_address_t *ip4_src_addresses;
+  u32 last_v4_address_rotor;
+  u32 last_v6_address_rotor;
+  ip6_address_t *ip6_src_addresses;
+
+	  /** vlib buffer size */
+  u32 bytes_per_buffer;
+
+  u8 punt_unknown4;
+  u8 punt_unknown6;
+
+  u32 sctp4_established_phase_node_index;
+  u32 sctp6_established_phase_node_index;
+
+  u16 msg_id_base;
+} sctp_main_t;
+
+extern sctp_main_t sctp_main;
+extern vlib_node_registration_t sctp4_input_node;
+extern vlib_node_registration_t sctp6_input_node;
+extern vlib_node_registration_t sctp4_output_node;
+extern vlib_node_registration_t sctp6_output_node;
+
+always_inline sctp_main_t *
+vnet_get_sctp_main ()
+{
+  return &sctp_main;
+}
+
+always_inline sctp_header_t *
+sctp_buffer_hdr (vlib_buffer_t * b)
+{
+  ASSERT ((signed) b->current_data >= (signed) -VLIB_BUFFER_PRE_DATA_SIZE);
+  return (sctp_header_t *) (b->data + b->current_data
+			    + sctp_buffer_opaque (b)->sctp.hdr_offset);
+}
+
+clib_error_t *vnet_sctp_enable_disable (vlib_main_t * vm, u8 is_en);
+clib_error_t *sctp_plugin_api_hookup (vlib_main_t * vm);
+
+always_inline sctp_connection_t *
+sctp_half_open_connection_get (u32 conn_index)
+{
+  sctp_connection_t *tc = 0;
+  clib_spinlock_lock_if_init (&sctp_main.half_open_lock);
+  if (!pool_is_free_index (sctp_main.half_open_connections, conn_index))
+    tc = pool_elt_at_index (sctp_main.half_open_connections, conn_index);
+  tc->sub_conn[SCTP_PRIMARY_PATH_IDX].subconn_idx = SCTP_PRIMARY_PATH_IDX;
+  clib_spinlock_unlock_if_init (&sctp_main.half_open_lock);
+  return tc;
+}
+
+/**
+ * Cleanup half-open connection
+ *
+ */
+always_inline void
+sctp_half_open_connection_del (sctp_connection_t * tc)
+{
+  sctp_main_t *sctp_main = vnet_get_sctp_main ();
+  clib_spinlock_lock_if_init (&sctp_main->half_open_lock);
+  pool_put_index (sctp_main->half_open_connections,
+		  tc->sub_conn[SCTP_PRIMARY_PATH_IDX].c_c_index);
+  if (CLIB_DEBUG)
+    clib_memset (tc, 0xFA, sizeof (*tc));
+  clib_spinlock_unlock_if_init (&sctp_main->half_open_lock);
+}
+
+always_inline u64
+sctp_set_time_now (u32 thread_index)
+{
+  sctp_main.time_now[thread_index] = clib_cpu_time_now ()
+    * sctp_main.tstamp_ticks_per_clock;
+  return sctp_main.time_now[thread_index];
+}
+
+always_inline void
+sctp_timer_set (sctp_connection_t * tc, u8 conn_idx, u8 timer_id,
+		u32 interval)
+{
+  ASSERT (tc->sub_conn[conn_idx].connection.thread_index ==
+	  vlib_get_thread_index ());
+  ASSERT (tc->sub_conn[conn_idx].timers[timer_id] ==
+	  SCTP_TIMER_HANDLE_INVALID);
+
+  sctp_sub_connection_t *sub = &tc->sub_conn[conn_idx];
+  sub->timers[timer_id] =
+    tw_timer_start_16t_2w_512sl (&sctp_main.timer_wheels[sub->c_thread_index],
+				 sub->c_c_index, timer_id, interval);
+}
+
+always_inline void
+sctp_timer_reset (sctp_connection_t * tc, u8 conn_idx, u8 timer_id)
+{
+  ASSERT (tc->sub_conn[conn_idx].c_thread_index == vlib_get_thread_index ());
+  if (tc->sub_conn[conn_idx].timers[timer_id] == SCTP_TIMER_HANDLE_INVALID)
+    return;
+
+  sctp_sub_connection_t *sub = &tc->sub_conn[conn_idx];
+
+  tw_timer_stop_16t_2w_512sl (&sctp_main.timer_wheels[sub->c_thread_index],
+			      sub->timers[timer_id]);
+  sub->timers[timer_id] = SCTP_TIMER_HANDLE_INVALID;
+}
+
+/**
+ * Try to cleanup half-open connection
+ *
+ * If called from a thread that doesn't own tc, the call won't have any
+ * effect.
+ *
+ * @param tc - connection to be cleaned up
+ * @return non-zero if cleanup failed.
+ */
+always_inline int
+sctp_half_open_connection_cleanup (sctp_connection_t * tc)
+{
+  /* Make sure this is the owning thread */
+  if (tc->sub_conn[SCTP_PRIMARY_PATH_IDX].c_thread_index !=
+      vlib_get_thread_index ())
+    return 1;
+  sctp_timer_reset (tc, SCTP_PRIMARY_PATH_IDX, SCTP_TIMER_T1_INIT);
+  sctp_half_open_connection_del (tc);
+  return 0;
+}
+
+always_inline u32
+sctp_header_bytes ()
+{
+  return sizeof (sctp_header_t);
+}
+
+always_inline sctp_connection_t *
+sctp_get_connection_from_transport (transport_connection_t * tconn)
+{
+  ASSERT (tconn != NULL);
+
+  sctp_sub_connection_t *sub = (sctp_sub_connection_t *) tconn;
+#if SCTP_ADV_DEBUG
+  if (sub == NULL)
+    SCTP_ADV_DBG ("sub == NULL");
+  if (sub->parent == NULL)
+    SCTP_ADV_DBG ("sub->parent == NULL");
+#endif
+  if (sub->subconn_idx > 0)
+    return (sctp_connection_t *) sub -
+      (sizeof (sctp_sub_connection_t) * (sub->subconn_idx - 1));
+
+  return (sctp_connection_t *) sub;
+}
+
+always_inline u64
+sctp_time_now (void)
+{
+  return sctp_main.time_now[vlib_get_thread_index ()];
+}
+
+#define ABS(x) ((x) > 0) ? (x) : -(x);
+
+always_inline void
+sctp_calculate_rto (sctp_connection_t * sctp_conn, u8 conn_idx)
+{
+  /* See RFC4960, 6.3.1.  RTO Calculation */
+  u64 RTO = 0;
+  f64 RTTVAR = 0;
+  u64 now = sctp_time_now ();
+  u64 prev_ts = sctp_conn->sub_conn[conn_idx].rtt_ts;
+  u64 R = prev_ts - now;
+
+  if (sctp_conn->sub_conn[conn_idx].RTO == 0)	// C1: Let's initialize our RTO
+    {
+      sctp_conn->sub_conn[conn_idx].RTO = SCTP_RTO_MIN;
+      return;
+    }
+
+  if (sctp_conn->sub_conn[conn_idx].RTO == SCTP_RTO_MIN && sctp_conn->sub_conn[conn_idx].SRTT == 0)	// C2: First RTT calculation
+    {
+      sctp_conn->sub_conn[conn_idx].SRTT = R;
+      RTTVAR = R / 2;
+
+      if (RTTVAR == 0)
+	RTTVAR = 100e-3;	/* 100 ms */
+
+      sctp_conn->sub_conn[conn_idx].RTTVAR = RTTVAR;
+    }
+  else				// C3: RTT already exists; let's recalculate
+    {
+      RTTVAR = (1 - SCTP_RTO_BETA) * sctp_conn->sub_conn[conn_idx].RTTVAR +
+	SCTP_RTO_BETA * ABS (sctp_conn->sub_conn[conn_idx].SRTT - R);
+
+      if (RTTVAR == 0)
+	RTTVAR = 100e-3;	/* 100 ms */
+
+      sctp_conn->sub_conn[conn_idx].RTTVAR = RTTVAR;
+
+      sctp_conn->sub_conn[conn_idx].SRTT =
+	(1 - SCTP_RTO_ALPHA) * sctp_conn->sub_conn[conn_idx].SRTT +
+	SCTP_RTO_ALPHA * R;
+    }
+
+  RTO =
+    sctp_conn->sub_conn[conn_idx].SRTT +
+    4 * sctp_conn->sub_conn[conn_idx].RTTVAR;
+  if (RTO < SCTP_RTO_MIN)	// C6
+    RTO = SCTP_RTO_MIN;
+
+  if (RTO > SCTP_RTO_MAX)	// C7
+    RTO = SCTP_RTO_MAX;
+
+  sctp_conn->sub_conn[conn_idx].RTO = RTO;
+}
+
+always_inline void
+sctp_timer_update (sctp_connection_t * tc, u8 conn_idx, u8 timer_id,
+		   u32 interval)
+{
+  ASSERT (tc->sub_conn[conn_idx].connection.thread_index ==
+	  vlib_get_thread_index ());
+  sctp_sub_connection_t *sub = &tc->sub_conn[conn_idx];
+
+  if (tc->sub_conn[conn_idx].timers[timer_id] != SCTP_TIMER_HANDLE_INVALID)
+    tw_timer_stop_16t_2w_512sl (&sctp_main.timer_wheels[sub->c_thread_index],
+				sub->timers[timer_id]);
+
+  tc->sub_conn[conn_idx].timers[timer_id] =
+    tw_timer_start_16t_2w_512sl (&sctp_main.timer_wheels[sub->c_thread_index],
+				 sub->c_c_index, timer_id, interval);
+}
+
+always_inline sctp_connection_t *
+sctp_listener_get (u32 tli)
+{
+  return pool_elt_at_index (sctp_main.listener_pool, tli);
+}
+
+#endif
+
+always_inline sctp_connection_t *
+sctp_connection_get (u32 conn_index, u32 thread_index)
+{
+  if (PREDICT_FALSE
+      (pool_is_free_index (sctp_main.connections[thread_index], conn_index)))
+    return 0;
+  return pool_elt_at_index (sctp_main.connections[thread_index], conn_index);
+}
+
+#define SELECT_MAX_RETRIES 8
+
+always_inline u8
+sctp_data_subconn_select (sctp_connection_t * sctp_conn)
+{
+  u32 sub = SCTP_PRIMARY_PATH_IDX;
+  u8 i, cwnd = sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].cwnd;
+  for (i = 1; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      if (sctp_conn->sub_conn[i].state == SCTP_SUBCONN_STATE_DOWN)
+	continue;
+
+      if (sctp_conn->sub_conn[i].cwnd > cwnd)
+	{
+	  sub = i;
+	  cwnd = sctp_conn->sub_conn[i].cwnd;
+	}
+    }
+  return sub;
+}
+
+always_inline u8
+sctp_sub_conn_id_via_ip6h (sctp_connection_t * sctp_conn, ip6_header_t * ip6h)
+{
+  u8 i;
+
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      if (sctp_conn->sub_conn[i].connection.lcl_ip.ip6.as_u64[0] ==
+	  ip6h->dst_address.as_u64[0] &&
+	  sctp_conn->sub_conn[i].connection.lcl_ip.ip6.as_u64[1] ==
+	  ip6h->dst_address.as_u64[1] &&
+	  sctp_conn->sub_conn[i].connection.rmt_ip.ip6.as_u64[0] ==
+	  ip6h->src_address.as_u64[0] &&
+	  sctp_conn->sub_conn[i].connection.rmt_ip.ip6.as_u64[1] ==
+	  ip6h->src_address.as_u64[1])
+	return i;
+    }
+  clib_warning ("Did not find a sub-connection; defaulting to %u",
+		SCTP_PRIMARY_PATH_IDX);
+  return SCTP_PRIMARY_PATH_IDX;
+}
+
+always_inline u8
+sctp_sub_conn_id_via_ip4h (sctp_connection_t * sctp_conn, ip4_header_t * ip4h)
+{
+  u8 i;
+
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      if (sctp_conn->sub_conn[i].connection.lcl_ip.ip4.as_u32 ==
+	  ip4h->dst_address.as_u32
+	  && sctp_conn->sub_conn[i].connection.rmt_ip.ip4.as_u32 ==
+	  ip4h->src_address.as_u32)
+	return i;
+    }
+  clib_warning ("Did not find a sub-connection; defaulting to %u",
+		SCTP_PRIMARY_PATH_IDX);
+  return SCTP_PRIMARY_PATH_IDX;
+}
+
+/**
+ * Push SCTP header to buffer
+ *
+ * @param vm - vlib_main
+ * @param b - buffer to write the header to
+ * @param sp_net - source port net order
+ * @param dp_net - destination port net order
+ * @param sctp_hdr_opts_len - header and options length in bytes
+ *
+ * @return - pointer to start of SCTP header
+ */
+always_inline void *
+vlib_buffer_push_sctp_net_order (vlib_buffer_t * b, u16 sp, u16 dp,
+				 u8 sctp_hdr_opts_len)
+{
+  sctp_full_hdr_t *full_hdr;
+
+  full_hdr = vlib_buffer_push_uninit (b, sctp_hdr_opts_len);
+
+  full_hdr->hdr.src_port = sp;
+  full_hdr->hdr.dst_port = dp;
+  full_hdr->hdr.checksum = 0;
+  return full_hdr;
+}
+
+/**
+ * Push SCTP header to buffer
+ *
+ * @param b - buffer to write the header to
+ * @param sp_net - source port net order
+ * @param dp_net - destination port net order
+ * @param sctp_hdr_opts_len - header and options length in bytes
+ *
+ * @return - pointer to start of SCTP header
+ */
+always_inline void *
+vlib_buffer_push_sctp (vlib_buffer_t * b, u16 sp_net, u16 dp_net,
+		       u8 sctp_hdr_opts_len)
+{
+  return vlib_buffer_push_sctp_net_order (b, sp_net, dp_net,
+					  sctp_hdr_opts_len);
+}
+
+always_inline u8
+sctp_next_avail_subconn (sctp_connection_t * sctp_conn)
+{
+  u8 i;
+
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      if (sctp_conn->sub_conn[i].state == SCTP_SUBCONN_STATE_DOWN)
+	return i;
+    }
+  return MAX_SCTP_CONNECTIONS;
+}
+
+always_inline void
+update_smallest_pmtu_idx (sctp_connection_t * sctp_conn)
+{
+  u8 i;
+  u8 smallest_pmtu_index = SCTP_PRIMARY_PATH_IDX;
+
+  for (i = 1; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      if (sctp_conn->sub_conn[i].state != SCTP_SUBCONN_STATE_DOWN)
+	{
+	  if (sctp_conn->sub_conn[i].PMTU <
+	      sctp_conn->sub_conn[smallest_pmtu_index].PMTU)
+	    smallest_pmtu_index = i;
+	}
+    }
+
+  sctp_conn->smallest_PMTU_idx = smallest_pmtu_index;
+}
+
+/* As per RFC4960; section 7.2.1: Slow-Start */
+always_inline void
+sctp_init_cwnd (sctp_connection_t * sctp_conn)
+{
+  u8 i;
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      /* Section 7.2.1; point (1) */
+      sctp_conn->sub_conn[i].cwnd =
+	clib_min (4 * sctp_conn->sub_conn[i].PMTU,
+		  clib_max (2 * sctp_conn->sub_conn[i].PMTU, 4380));
+
+      /* Section 7.2.1; point (3) */
+      sctp_conn->sub_conn[i].ssthresh = SCTP_INITIAL_SSHTRESH;
+
+      /* Section 7.2.2; point (1) */
+      sctp_conn->sub_conn[i].partially_acked_bytes = 0;
+    }
+}
+
+always_inline u8
+sctp_in_cong_recovery (sctp_connection_t * sctp_conn, u8 idx)
+{
+  return 0;
+}
+
+always_inline u8
+cwnd_fully_utilized (sctp_connection_t * sctp_conn, u8 idx)
+{
+  if (sctp_conn->sub_conn[idx].cwnd == 0)
+    return 1;
+  return 0;
+}
+
+/* As per RFC4960; section 7.2.1: Slow-Start */
+always_inline void
+update_cwnd (sctp_connection_t * sctp_conn)
+{
+  u8 i;
+  u32 inflight = sctp_conn->next_tsn - sctp_conn->last_unacked_tsn;
+
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      /* Section 7.2.1; point (2) */
+      if (sctp_conn->sub_conn[i].is_retransmitting)
+	{
+	  sctp_conn->sub_conn[i].cwnd = 1 * sctp_conn->sub_conn[i].PMTU;
+	  continue;
+	}
+
+      /* Section 7.2.2; point (4) */
+      if (sctp_conn->sub_conn[i].last_data_ts >
+	  sctp_time_now () + SCTP_DATA_IDLE_INTERVAL)
+	{
+	  sctp_conn->sub_conn[i].cwnd =
+	    clib_max (sctp_conn->sub_conn[i].cwnd / 2,
+		      4 * sctp_conn->sub_conn[i].PMTU);
+	  continue;
+	}
+
+      /* Section 7.2.1; point (5) */
+      if (sctp_conn->sub_conn[i].cwnd <= sctp_conn->sub_conn[i].ssthresh)
+	{
+	  if (!cwnd_fully_utilized (sctp_conn, i))
+	    continue;
+
+	  if (sctp_in_cong_recovery (sctp_conn, i))
+	    continue;
+
+	  sctp_conn->sub_conn[i].cwnd =
+	    clib_min (sctp_conn->sub_conn[i].PMTU, 1);
+	}
+
+      /* Section 6.1; point (D) */
+      if ((inflight + SCTP_RTO_BURST * sctp_conn->sub_conn[i].PMTU) <
+	  sctp_conn->sub_conn[i].cwnd)
+	sctp_conn->sub_conn[i].cwnd =
+	  inflight + SCTP_RTO_BURST * sctp_conn->sub_conn[i].PMTU;
+    }
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp_all_api_h.h b/src/plugins/sctp/sctp_all_api_h.h
new file mode 100644
index 00000000000..16bba76239e
--- /dev/null
+++ b/src/plugins/sctp/sctp_all_api_h.h
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/* Include the generated file, see BUILT_SOURCES in Makefile.am */
+#include <sctp/sctp.api.h>
diff --git a/src/plugins/sctp/sctp_api.c b/src/plugins/sctp/sctp_api.c
new file mode 100644
index 00000000000..7702d340aae
--- /dev/null
+++ b/src/plugins/sctp/sctp_api.c
@@ -0,0 +1,158 @@
+/*
+ *------------------------------------------------------------------
+ * sctp_api.c - sctp-layer API
+ *
+ * Copyright (c) 2018 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <vlib/vlib.h>
+#include <vlibapi/api.h>
+#include <vlibmemory/api.h>
+
+#include <sctp/sctp.h>
+
+#include <sctp/sctp_msg_enum.h>
+
+#define vl_typedefs		/* define message structures */
+#include <sctp/sctp_all_api_h.h>
+#undef vl_typedefs
+
+#define vl_endianfun		/* define message structures */
+#include <sctp/sctp_all_api_h.h>
+#undef vl_endianfun
+
+/* instantiate all the print functions we know about */
+#define vl_print(handle, ...) vlib_cli_output (handle, __VA_ARGS__)
+#define vl_printfun
+#include <sctp/sctp_all_api_h.h>
+#undef vl_printfun
+
+#define vl_api_version(n,v) static u32 api_version=(v);
+#include <sctp/sctp_all_api_h.h>
+#undef vl_api_version
+
+#define REPLY_MSG_ID_BASE sctp_main.msg_id_base
+#include <vlibapi/api_helper_macros.h>
+
+#define foreach_sctp_plugin_api_msg					\
+_(SCTP_ADD_SRC_DST_CONNECTION, sctp_add_src_dst_connection)		\
+_(SCTP_DEL_SRC_DST_CONNECTION, sctp_del_src_dst_connection)		\
+_(SCTP_CONFIG, sctp_config)
+
+static void
+  vl_api_sctp_add_src_dst_connection_t_handler
+  (vl_api_sctp_add_src_dst_connection_t * mp)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  vl_api_sctp_add_src_dst_connection_reply_t *rmp;
+  int rv;
+
+  if (mp->is_ipv6)
+    rv = sctp_sub_connection_add_ip6
+      (vm,
+       (ip6_address_t *) mp->src_address, (ip6_address_t *) mp->dst_address);
+  else
+    rv = sctp_sub_connection_add_ip4
+      (vm,
+       (ip4_address_t *) mp->src_address, (ip4_address_t *) mp->dst_address);
+
+  REPLY_MACRO (VL_API_SCTP_ADD_SRC_DST_CONNECTION_REPLY);
+}
+
+static void
+  vl_api_sctp_del_src_dst_connection_t_handler
+  (vl_api_sctp_del_src_dst_connection_t * mp)
+{
+  vl_api_sctp_del_src_dst_connection_reply_t *rmp;
+  int rv;
+
+  if (mp->is_ipv6)
+    rv = sctp_sub_connection_del_ip6
+      ((ip6_address_t *) mp->src_address, (ip6_address_t *) mp->dst_address);
+  else
+    rv = sctp_sub_connection_del_ip4
+      ((ip4_address_t *) mp->src_address, (ip4_address_t *) mp->dst_address);
+
+  REPLY_MACRO (VL_API_SCTP_ADD_SRC_DST_CONNECTION_REPLY);
+}
+
+static void
+vl_api_sctp_config_t_handler (vl_api_sctp_config_t * mp)
+{
+  sctp_user_configuration_t config;
+  vl_api_sctp_config_reply_t *rmp;
+  int rv;
+
+  config.never_delay_sack = mp->never_delay_sack;
+  config.never_bundle = mp->never_bundle;
+  rv = sctp_configure (config);
+
+  REPLY_MACRO (VL_API_SCTP_CONFIG_REPLY);
+}
+
+#define vl_msg_name_crc_list
+#include <sctp/sctp_all_api_h.h>
+#undef vl_msg_name_crc_list
+
+static void
+setup_message_id_table (sctp_main_t * sm, api_main_t * am)
+{
+#define _(id,n,crc) \
+  vl_msg_api_add_msg_name_crc (am, #n "_" #crc, id + sm->msg_id_base);
+  foreach_vl_msg_name_crc_sctp;
+#undef _
+}
+
+clib_error_t *
+sctp_plugin_api_hookup (vlib_main_t * vm)
+{
+  sctp_main_t *sm = &sctp_main;
+  api_main_t *am = &api_main;
+  u8 *name;
+
+  /* Construct the API name */
+  name = format (0, "sctp_%08x%c", api_version, 0);
+
+  /* Ask for a correctly-sized block of API message decode slots */
+  sctp_main.msg_id_base = vl_msg_api_get_msg_ids
+    ((char *) name, VL_MSG_FIRST_AVAILABLE);
+
+#define _(N,n)                                                  \
+    vl_msg_api_set_handlers((VL_API_##N + sm->msg_id_base),     \
+                           #n,                                  \
+                           vl_api_##n##_t_handler,              \
+                           vl_noop_handler,                     \
+                           vl_api_##n##_t_endian,               \
+                           vl_api_##n##_t_print,                \
+                           sizeof(vl_api_##n##_t), 1);
+  foreach_sctp_plugin_api_msg;
+#undef _
+
+  /*
+   * Set up the (msg_name, crc, message-id) table
+   */
+  setup_message_id_table (sm, am);
+  vec_free (name);
+
+  return 0;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp_debug.h b/src/plugins/sctp/sctp_debug.h
new file mode 100644
index 00000000000..b0059d5fe67
--- /dev/null
+++ b/src/plugins/sctp/sctp_debug.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_sctp_debug_h__
+#define included_sctp_debug_h__
+
+#include <vlib/vlib.h>
+
+typedef enum _sctp_dbg
+{
+#define _(sym, str) SCTP_DBG_##sym,
+  foreach_sctp_dbg_evt
+#undef _
+} sctp_dbg_e;
+
+#define SCTP_DEBUG_STATE_MACHINE (0)
+#if SCTP_DEBUG_STATE_MACHINE
+#define SCTP_DBG_STATE_MACHINE(_fmt, _args...) clib_warning (_fmt, ##_args)
+#else
+#define SCTP_DBG_STATE_MACHINE(_fmt, _args...)
+#endif
+
+#define SCTP_DEBUG (0)
+#if SCTP_DEBUG
+#define SCTP_DBG(_fmt, _args...) clib_warning (_fmt, ##_args)
+#else
+#define SCTP_DBG(_fmt, _args...)
+#endif
+
+#define SCTP_ADV_DEBUG (0)
+#if SCTP_ADV_DEBUG
+#define SCTP_ADV_DBG(_fmt, _args...) clib_warning (_fmt, ##_args)
+#else
+#define SCTP_ADV_DBG(_fmt, _args...)
+#endif
+
+#define SCTP_DEBUG_OUTPUT (0)
+#if SCTP_DEBUG_OUTPUT
+#define SCTP_DBG_OUTPUT(_fmt, _args...) clib_warning (_fmt, ##_args)
+#else
+#define SCTP_DBG_OUTPUT(_fmt, _args...)
+#endif
+
+#define SCTP_ADV_DEBUG_OUTPUT (0)
+#if SCTP_ADV_DEBUG_OUTPUT
+#define SCTP_ADV_DBG_OUTPUT(_fmt, _args...) clib_warning (_fmt, ##_args)
+#else
+#define SCTP_ADV_DBG_OUTPUT(_fmt, _args...)
+#endif
+
+#define SCTP_CONN_TRACKING_DEBUG (0)
+#if SCTP_CONN_TRACKING_DEBUG
+#define SCTP_CONN_TRACKING_DBG(_fmt, _args...) clib_warning (_fmt, ##_args)
+#else
+#define SCTP_CONN_TRACKING_DBG(_fmt, _args...)
+#endif
+
+#endif /* included_sctp_debug_h__ */
diff --git a/src/plugins/sctp/sctp_error.def b/src/plugins/sctp/sctp_error.def
new file mode 100644
index 00000000000..b95b71a9417
--- /dev/null
+++ b/src/plugins/sctp/sctp_error.def
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+sctp_error (NONE, "no error")
+sctp_error (WRONG_WORKER, "Wrong worker thread")
+sctp_error (FILTERED, "Packets filtered")
+sctp_error (PKTS_SENT, "Packets sent")
+sctp_error (INVALID_CONNECTION, "Invalid connection")
+sctp_error (INVALID_TAG, "Invalid verification tag")
+sctp_error (INVALID_TAG_FOR_INIT, "Invalid verification tag for INIT chunk")
+sctp_error (CONNECTION_CLOSED, "Connection closed")
+sctp_error (ENQUEUED, "Packets pushed into rx fifo")
+sctp_error (CREATE_EXISTS, "Connection already exists")
+sctp_error (INITS_RCVD, "INITs received")
+sctp_error (CREATE_SESSION_FAIL, "Sessions couldn't be allocated")
+sctp_error (NO_LISTENER, "no listener for dst port")
+sctp_error (LENGTH, "inconsistent ip/sctp lengths")
+sctp_error (DISPATCH, "Dispatch error")
+sctp_error (ACK_DUP, "Duplicate ACK")
+sctp_error (DATA_CHUNK_VIOLATION, "DATA chunk received in invalid state")
+sctp_error (INIT_CHUNK_VIOLATION, "INIT chunk received in the wrong state")
+sctp_error (INIT_ACK_CHUNK_VIOLATION, "INIT_ACK chunk received in the wrong state")
+sctp_error (SACK_CHUNK_VIOLATION, "SACK chunk received in invalid state")
+sctp_error (HEARTBEAT_CHUNK_VIOLATION, "HEARTBEAT chunk received in invalid state")
+sctp_error (HEARTBEAT_ACK_CHUNK_VIOLATION, "HEARTBEAT_ACK chunk received in invalid state")
+sctp_error (ABORT_CHUNK_VIOLATION, "ABORT_CHUNK chunk received in invalid state")
+sctp_error (SHUTDOWN_CHUNK_VIOLATION, "SHUTDOWN chunk received in invalid state")
+sctp_error (SHUTDOWN_ACK_CHUNK_VIOLATION, "SHUTDOWN_ACK chunk received in invalid state")
+sctp_error (OPERATION_ERROR_VIOLATION, "OPERATION_ERROR chunk received in invalid state")
+sctp_error (COOKIE_ECHO_VIOLATION, "COOKIE_ECHO chunk received in invalid state")
+sctp_error (COOKIE_ACK_VIOLATION, "COOKIE_ACK chunk received in invalid state")
+sctp_error (ECNE_VIOLATION, "ECNE chunk received in invalid state")
+sctp_error (CWR_VIOLATION, "CWR chunk received in invalid state")
+sctp_error (SHUTDOWN_COMPLETE_VIOLATION, "SHUTDOWN_COMPLETE chunk received in invalid state")
+sctp_error (FIFO_FULL, "Packets dropped for lack of rx fifo space") 
+sctp_error (PARTIALLY_ENQUEUED, "Packets partially pushed into rx fifo") 
+sctp_error (EVENT_FIFO_FULL, "Events not sent for lack of event fifo space") 
+sctp_error (UNKNOWN_CHUNK, "Unrecognized / unknown chunk or chunk-state mismatch")
+sctp_error (BUNDLING_VIOLATION, "Bundling not allowed")
+sctp_error (PUNT, "Packets punted")
+sctp_error (MAX_CONNECTIONS, "Reached max supported subconnection")
diff --git a/src/plugins/sctp/sctp_format.c b/src/plugins/sctp/sctp_format.c
new file mode 100644
index 00000000000..99430c70c2c
--- /dev/null
+++ b/src/plugins/sctp/sctp_format.c
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sctp/sctp.h>
+
+/* Format SCTP header. */
+u8 *
+format_sctp_header (u8 * s, va_list * args)
+{
+  return NULL;
+}
+
+u8 *
+format_sctp_tx_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+
+  return NULL;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp_input.c b/src/plugins/sctp/sctp_input.c
new file mode 100644
index 00000000000..7f52a2f9c32
--- /dev/null
+++ b/src/plugins/sctp/sctp_input.c
@@ -0,0 +1,2532 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <vppinfra/sparse_vec.h>
+#include <sctp/sctp.h>
+#include <sctp/sctp_packet.h>
+#include <sctp/sctp_debug.h>
+#include <vnet/session/session.h>
+#include <math.h>
+
+static char *sctp_error_strings[] = {
+#define sctp_error(n,s) s,
+#include <sctp/sctp_error.def>
+#undef sctp_error
+};
+
+/* All SCTP nodes have the same outgoing arcs */
+#define foreach_sctp_state_next                  \
+  _ (DROP4, "ip4-drop")                         \
+  _ (DROP6, "ip6-drop")                         \
+  _ (SCTP4_OUTPUT, "sctp4-output")                \
+  _ (SCTP6_OUTPUT, "sctp6-output")
+
+typedef enum _sctp_established_phase_next
+{
+#define _(s,n) SCTP_ESTABLISHED_PHASE_NEXT_##s,
+  foreach_sctp_state_next
+#undef _
+    SCTP_ESTABLISHED_PHASE_N_NEXT,
+} sctp_established_phase_next_t;
+
+typedef enum _sctp_rcv_phase_next
+{
+#define _(s,n) SCTP_RCV_PHASE_NEXT_##s,
+  foreach_sctp_state_next
+#undef _
+    SCTP_RCV_PHASE_N_NEXT,
+} sctp_rcv_phase_next_t;
+
+typedef enum _sctp_listen_phase_next
+{
+#define _(s,n) SCTP_LISTEN_PHASE_NEXT_##s,
+  foreach_sctp_state_next
+#undef _
+    SCTP_LISTEN_PHASE_N_NEXT,
+} sctp_listen_phase_next_t;
+
+typedef enum _sctp_shutdown_phase_next
+{
+#define _(s,n) SCTP_SHUTDOWN_PHASE_NEXT_##s,
+  foreach_sctp_state_next
+#undef _
+    SCTP_SHUTDOWN_PHASE_N_NEXT,
+} sctp_shutdown_phase_next_t;
+
+/* Generic, state independent indices */
+typedef enum _sctp_state_next
+{
+#define _(s,n) SCTP_NEXT_##s,
+  foreach_sctp_state_next
+#undef _
+    SCTP_STATE_N_NEXT,
+} sctp_state_next_t;
+
+typedef enum _sctp_input_next
+{
+  SCTP_INPUT_NEXT_DROP,
+  SCTP_INPUT_NEXT_LISTEN_PHASE,
+  SCTP_INPUT_NEXT_RCV_PHASE,
+  SCTP_INPUT_NEXT_ESTABLISHED_PHASE,
+  SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+  SCTP_INPUT_NEXT_PUNT_PHASE,
+  SCTP_INPUT_N_NEXT
+} sctp_input_next_t;
+
+#ifndef CLIB_MARCH_VARIANT
+char *
+phase_to_string (u8 phase)
+{
+  switch (phase)
+    {
+    case SCTP_INPUT_NEXT_DROP:
+      return "SCTP_INPUT_NEXT_DROP";
+    case SCTP_INPUT_NEXT_LISTEN_PHASE:
+      return "SCTP_INPUT_NEXT_LISTEN_PHASE";
+    case SCTP_INPUT_NEXT_RCV_PHASE:
+      return "SCTP_INPUT_NEXT_RCV_PHASE";
+    case SCTP_INPUT_NEXT_ESTABLISHED_PHASE:
+      return "SCTP_INPUT_NEXT_ESTABLISHED_PHASE";
+    case SCTP_INPUT_NEXT_SHUTDOWN_PHASE:
+      return "SCTP_INPUT_NEXT_SHUTDOWN_PHASE";
+    case SCTP_INPUT_NEXT_PUNT_PHASE:
+      return "SCTP_INPUT_NEXT_PUNT_PHASE";
+    }
+  return NULL;
+}
+#endif /* CLIB_MARCH_VARIANT */
+
+#define foreach_sctp4_input_next                 \
+  _ (DROP, "error-drop")                         \
+  _ (RCV_PHASE, "sctp4-rcv")                    \
+  _ (LISTEN_PHASE, "sctp4-listen")     	 \
+  _ (ESTABLISHED_PHASE, "sctp4-established")     	 \
+  _ (SHUTDOWN_PHASE, "sctp4-shutdown")	\
+  _ (PUNT_PHASE, "ip4-punt")
+
+
+#define foreach_sctp6_input_next                 \
+  _ (DROP, "error-drop")                         \
+  _ (RCV_PHASE, "sctp6-rcv")                    \
+  _ (LISTEN_PHASE, "sctp6-listen")     	 \
+  _ (ESTABLISHED_PHASE, "sctp6-established")     	 \
+  _ (SHUTDOWN_PHASE, "sctp6-shutdown")		\
+  _ (PUNT_PHASE, "ip6-punt")
+
+static u8
+sctp_lookup_is_valid (transport_connection_t * trans_conn,
+		      sctp_header_t * sctp_hdr)
+{
+  sctp_connection_t *sctp_conn =
+    sctp_get_connection_from_transport (trans_conn);
+
+  if (!sctp_conn)
+    return 1;
+
+  u8 is_valid = (trans_conn->lcl_port == sctp_hdr->dst_port
+		 && (sctp_conn->state == SCTP_STATE_CLOSED
+		     || trans_conn->rmt_port == sctp_hdr->src_port));
+
+  return is_valid;
+}
+
+/**
+ * Lookup transport connection
+ */
+static sctp_connection_t *
+sctp_lookup_connection (u32 fib_index, vlib_buffer_t * b, u8 thread_index,
+			u8 is_ip4)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  sctp_header_t *sctp_hdr;
+  transport_connection_t *trans_conn;
+  sctp_connection_t *sctp_conn;
+  u8 is_filtered, i;
+  if (is_ip4)
+    {
+      ip4_header_t *ip4_hdr;
+      ip4_hdr = vlib_buffer_get_current (b);
+      sctp_hdr = ip4_next_header (ip4_hdr);
+      trans_conn = session_lookup_connection_wt4 (fib_index,
+						  &ip4_hdr->dst_address,
+						  &ip4_hdr->src_address,
+						  sctp_hdr->dst_port,
+						  sctp_hdr->src_port,
+						  TRANSPORT_PROTO_SCTP,
+						  thread_index, &is_filtered);
+      if (trans_conn == 0)	/* Not primary connection */
+	{
+	  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+	    {
+	      if ((tm->connections[thread_index]->sub_conn[i].
+		   connection.lcl_ip.ip4.as_u32 ==
+		   ip4_hdr->dst_address.as_u32)
+		  && (tm->connections[thread_index]->sub_conn[i].
+		      connection.rmt_ip.ip4.as_u32 ==
+		      ip4_hdr->src_address.as_u32))
+		{
+		  trans_conn =
+		    &tm->connections[thread_index]->sub_conn[i].connection;
+		  break;
+		}
+	    }
+	}
+      ASSERT (trans_conn != 0);
+      ASSERT (sctp_lookup_is_valid (trans_conn, sctp_hdr));
+    }
+  else
+    {
+      ip6_header_t *ip6_hdr;
+      ip6_hdr = vlib_buffer_get_current (b);
+      sctp_hdr = ip6_next_header (ip6_hdr);
+      trans_conn = session_lookup_connection_wt6 (fib_index,
+						  &ip6_hdr->dst_address,
+						  &ip6_hdr->src_address,
+						  sctp_hdr->dst_port,
+						  sctp_hdr->src_port,
+						  TRANSPORT_PROTO_SCTP,
+						  thread_index, &is_filtered);
+      if (trans_conn == 0)	/* Not primary connection */
+	{
+	  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+	    {
+	      if ((tm->connections[thread_index]->sub_conn[i].
+		   connection.lcl_ip.ip6.as_u64[0] ==
+		   ip6_hdr->dst_address.as_u64[0]
+		   && tm->connections[thread_index]->sub_conn[i].
+		   connection.lcl_ip.ip6.as_u64[1] ==
+		   ip6_hdr->dst_address.as_u64[1])
+		  && (tm->connections[thread_index]->sub_conn[i].
+		      connection.rmt_ip.ip6.as_u64[0] ==
+		      ip6_hdr->src_address.as_u64[0]
+		      && tm->connections[thread_index]->
+		      sub_conn[i].connection.rmt_ip.ip6.as_u64[1] ==
+		      ip6_hdr->src_address.as_u64[1]))
+		{
+		  trans_conn =
+		    &tm->connections[thread_index]->sub_conn[i].connection;
+		  break;
+		}
+	    }
+	}
+      ASSERT (trans_conn != 0);
+      ASSERT (sctp_lookup_is_valid (trans_conn, sctp_hdr));
+    }
+  sctp_conn = sctp_get_connection_from_transport (trans_conn);
+  return sctp_conn;
+}
+
+typedef struct
+{
+  sctp_header_t sctp_header;
+  sctp_connection_t sctp_connection;
+} sctp_rx_trace_t;
+
+#define sctp_next_output(is_ip4) (is_ip4 ? SCTP_NEXT_SCTP4_OUTPUT          \
+                                        : SCTP_NEXT_SCTP6_OUTPUT)
+
+#define sctp_next_drop(is_ip4) (is_ip4 ? SCTP_NEXT_DROP4                  \
+                                      : SCTP_NEXT_DROP6)
+
+static void
+sctp_set_rx_trace_data (sctp_rx_trace_t * rx_trace,
+			sctp_connection_t * sctp_conn,
+			sctp_header_t * sctp_hdr, vlib_buffer_t * b0,
+			u8 is_ip4)
+{
+  if (sctp_conn)
+    {
+      clib_memcpy_fast (&rx_trace->sctp_connection, sctp_conn,
+			sizeof (rx_trace->sctp_connection));
+    }
+  else
+    {
+      sctp_hdr = sctp_buffer_hdr (b0);
+    }
+  clib_memcpy_fast (&rx_trace->sctp_header, sctp_hdr,
+		    sizeof (rx_trace->sctp_header));
+}
+
+always_inline u16
+sctp_calculate_implied_length (ip4_header_t * ip4_hdr, ip6_header_t * ip6_hdr,
+			       int is_ip4)
+{
+  u16 sctp_implied_packet_length = 0;
+
+  if (is_ip4)
+    sctp_implied_packet_length =
+      clib_net_to_host_u16 (ip4_hdr->length) - ip4_header_bytes (ip4_hdr);
+  else
+    sctp_implied_packet_length =
+      clib_net_to_host_u16 (ip6_hdr->payload_length) - sizeof (ip6_hdr);
+
+  return sctp_implied_packet_length;
+}
+
+always_inline u8
+sctp_is_bundling (u16 sctp_implied_length,
+		  sctp_chunks_common_hdr_t * sctp_common_hdr)
+{
+  if (sctp_implied_length !=
+      sizeof (sctp_header_t) + vnet_sctp_get_chunk_length (sctp_common_hdr))
+    return 1;
+  return 0;
+}
+
+always_inline u16
+sctp_handle_operation_err (sctp_header_t * sctp_hdr,
+			   sctp_connection_t * sctp_conn, u8 idx,
+			   vlib_buffer_t * b, u16 * next0)
+{
+  sctp_operation_error_t *op_err = (sctp_operation_error_t *) sctp_hdr;
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
+    {
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  if (clib_net_to_host_u16 (op_err->err_causes[0].param_hdr.type) ==
+      STALE_COOKIE_ERROR)
+    {
+      if (sctp_conn->state != SCTP_STATE_COOKIE_ECHOED)
+	*next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      else
+	{
+	  sctp_connection_cleanup (sctp_conn);
+
+	  session_transport_closing_notify (&sctp_conn->
+					    sub_conn[idx].connection);
+	}
+    }
+
+  return SCTP_ERROR_NONE;
+}
+
+always_inline u16
+sctp_handle_init (sctp_header_t * sctp_hdr,
+		  sctp_chunks_common_hdr_t * sctp_chunk_hdr,
+		  sctp_connection_t * sctp_conn, vlib_buffer_t * b0,
+		  u16 sctp_implied_length)
+{
+  sctp_init_chunk_t *init_chunk = (sctp_init_chunk_t *) (sctp_hdr);
+  ip4_address_t ip4_addr;
+  ip6_address_t ip6_addr;
+  u8 add_ip4 = 0;
+  u8 add_ip6 = 0;
+  char hostname[FQDN_MAX_LENGTH];
+
+  /* Check the current state of the connection
+   *
+   * The logic required by the RFC4960 Section 5.2.2 is already taken care of
+   * in the code below and by the "sctp_prepare_initack_chunk" function.
+   * However, for debugging purposes it is nice to have a message printed out
+   * for these corner-case scenarios.
+   */
+  if (sctp_conn->state != SCTP_STATE_CLOSED)
+    {				/* UNEXPECTED scenario */
+      switch (sctp_conn->state)
+	{
+	case SCTP_STATE_COOKIE_WAIT:
+	  SCTP_ADV_DBG ("Received INIT chunk while in COOKIE_WAIT state");
+	  sctp_prepare_initack_chunk_for_collision (sctp_conn,
+						    SCTP_PRIMARY_PATH_IDX,
+						    b0, &ip4_addr, &ip6_addr);
+	  return SCTP_ERROR_NONE;
+	case SCTP_STATE_COOKIE_ECHOED:
+	case SCTP_STATE_SHUTDOWN_ACK_SENT:
+	  SCTP_ADV_DBG ("Received INIT chunk while in COOKIE_ECHOED state");
+	  if (sctp_conn->forming_association_changed == 0)
+	    sctp_prepare_initack_chunk_for_collision (sctp_conn,
+						      SCTP_PRIMARY_PATH_IDX,
+						      b0, &ip4_addr,
+						      &ip6_addr);
+	  else
+	    sctp_prepare_abort_for_collision (sctp_conn,
+					      SCTP_PRIMARY_PATH_IDX, b0,
+					      &ip4_addr, &ip6_addr);
+	  return SCTP_ERROR_NONE;
+	}
+    }
+
+  if (sctp_hdr->verification_tag != 0x0)
+    return SCTP_ERROR_INVALID_TAG_FOR_INIT;
+
+  /*
+   * It is not possible to bundle any other CHUNK with the INIT chunk
+   */
+  if (sctp_is_bundling (sctp_implied_length, &init_chunk->chunk_hdr))
+    return SCTP_ERROR_BUNDLING_VIOLATION;
+
+  /* Save the INITIATE_TAG of the remote peer for this connection:
+   * it MUST be used for the VERIFICATION_TAG parameter in the SCTP HEADER */
+  sctp_conn->remote_tag = init_chunk->initiate_tag;
+  sctp_conn->remote_initial_tsn =
+    clib_net_to_host_u32 (init_chunk->initial_tsn);
+  sctp_conn->last_rcvd_tsn = sctp_conn->remote_initial_tsn;
+  sctp_conn->next_tsn_expected = sctp_conn->remote_initial_tsn + 1;
+  SCTP_CONN_TRACKING_DBG ("sctp_conn->remote_initial_tsn = %u",
+			  sctp_conn->remote_initial_tsn);
+
+  sctp_conn->peer_rwnd = clib_net_to_host_u32 (init_chunk->a_rwnd);
+  /*
+   * If the length specified in the INIT message is bigger than the size in bytes of our structure it means that
+   * optional parameters have been sent with the INIT chunk and we need to parse them.
+   */
+  u16 length = vnet_sctp_get_chunk_length (sctp_chunk_hdr);
+  if (length > sizeof (sctp_init_chunk_t))
+    {
+      /* There are optional parameters in the INIT chunk */
+      u16 pointer_offset = sizeof (sctp_init_chunk_t);
+      while (pointer_offset < length)
+	{
+	  sctp_opt_params_hdr_t *opt_params_hdr =
+	    (sctp_opt_params_hdr_t *) init_chunk + pointer_offset;
+
+	  switch (clib_net_to_host_u16 (opt_params_hdr->type))
+	    {
+	    case SCTP_IPV4_ADDRESS_TYPE:
+	      {
+		sctp_ipv4_addr_param_t *ipv4 =
+		  (sctp_ipv4_addr_param_t *) opt_params_hdr;
+		clib_memcpy_fast (&ip4_addr, &ipv4->address,
+				  sizeof (ip4_address_t));
+
+		if (sctp_sub_connection_add_ip4 (vlib_get_main (),
+						 &sctp_conn->sub_conn
+						 [SCTP_PRIMARY_PATH_IDX].connection.
+						 lcl_ip.ip4,
+						 &ipv4->address) ==
+		    SCTP_ERROR_NONE)
+		  add_ip4 = 1;
+
+		break;
+	      }
+	    case SCTP_IPV6_ADDRESS_TYPE:
+	      {
+		sctp_ipv6_addr_param_t *ipv6 =
+		  (sctp_ipv6_addr_param_t *) opt_params_hdr;
+		clib_memcpy_fast (&ip6_addr, &ipv6->address,
+				  sizeof (ip6_address_t));
+
+		if (sctp_sub_connection_add_ip6 (vlib_get_main (),
+						 &sctp_conn->sub_conn
+						 [SCTP_PRIMARY_PATH_IDX].connection.
+						 lcl_ip.ip6,
+						 &ipv6->address) ==
+		    SCTP_ERROR_NONE)
+		  add_ip6 = 1;
+
+		break;
+	      }
+	    case SCTP_COOKIE_PRESERVATIVE_TYPE:
+	      {
+		sctp_cookie_preservative_param_t *cookie_pres =
+		  (sctp_cookie_preservative_param_t *) opt_params_hdr;
+		sctp_conn->peer_cookie_life_span_increment =
+		  cookie_pres->life_span_inc;
+		break;
+	      }
+	    case SCTP_HOSTNAME_ADDRESS_TYPE:
+	      {
+		sctp_hostname_param_t *hostname_addr =
+		  (sctp_hostname_param_t *) opt_params_hdr;
+		clib_memcpy_fast (hostname, hostname_addr->hostname,
+				  FQDN_MAX_LENGTH);
+		break;
+	      }
+	    case SCTP_SUPPORTED_ADDRESS_TYPES:
+	      {
+		/* TODO */
+		break;
+	      }
+	    }
+	  pointer_offset += clib_net_to_host_u16 (opt_params_hdr->length);
+	}
+    }
+
+  /* Reuse buffer to make init-ack and send */
+  sctp_prepare_initack_chunk (sctp_conn, SCTP_PRIMARY_PATH_IDX, b0, &ip4_addr,
+			      add_ip4, &ip6_addr, add_ip6);
+  return SCTP_ERROR_NONE;
+}
+
+always_inline u16
+sctp_is_valid_init_ack (sctp_header_t * sctp_hdr,
+			sctp_chunks_common_hdr_t * sctp_chunk_hdr,
+			sctp_connection_t * sctp_conn, vlib_buffer_t * b0,
+			u16 sctp_implied_length)
+{
+  sctp_init_ack_chunk_t *init_ack_chunk =
+    (sctp_init_ack_chunk_t *) (sctp_hdr);
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != init_ack_chunk->sctp_hdr.verification_tag)
+    {
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  /*
+   * It is not possible to bundle any other CHUNK with the INIT_ACK chunk
+   */
+  if (sctp_is_bundling (sctp_implied_length, &init_ack_chunk->chunk_hdr))
+    return SCTP_ERROR_BUNDLING_VIOLATION;
+
+  return SCTP_ERROR_NONE;
+}
+
+always_inline u16
+sctp_handle_init_ack (sctp_header_t * sctp_hdr,
+		      sctp_chunks_common_hdr_t * sctp_chunk_hdr,
+		      sctp_connection_t * sctp_conn, u8 idx,
+		      vlib_buffer_t * b0, u16 sctp_implied_length)
+{
+  sctp_init_ack_chunk_t *init_ack_chunk =
+    (sctp_init_ack_chunk_t *) (sctp_hdr);
+
+  char hostname[FQDN_MAX_LENGTH];
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != init_ack_chunk->sctp_hdr.verification_tag)
+    {
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  /*
+   * It is not possible to bundle any other CHUNK with the INIT chunk
+   */
+  if (sctp_is_bundling (sctp_implied_length, &init_ack_chunk->chunk_hdr))
+    return SCTP_ERROR_BUNDLING_VIOLATION;
+
+  /* Stop the T1_INIT timer */
+  sctp_timer_reset (sctp_conn, idx, SCTP_TIMER_T1_INIT);
+
+  sctp_calculate_rto (sctp_conn, idx);
+
+  /* remote_tag to be placed in the VERIFICATION_TAG field of the COOKIE_ECHO chunk */
+  sctp_conn->remote_tag = init_ack_chunk->initiate_tag;
+  sctp_conn->remote_initial_tsn =
+    clib_net_to_host_u32 (init_ack_chunk->initial_tsn);
+  sctp_conn->last_rcvd_tsn = sctp_conn->remote_initial_tsn;
+  sctp_conn->next_tsn_expected = sctp_conn->remote_initial_tsn + 1;
+  SCTP_CONN_TRACKING_DBG ("sctp_conn->remote_initial_tsn = %u",
+			  sctp_conn->remote_initial_tsn);
+  sctp_conn->peer_rwnd = clib_net_to_host_u32 (init_ack_chunk->a_rwnd);
+
+  u16 length = vnet_sctp_get_chunk_length (sctp_chunk_hdr);
+
+  if (length > sizeof (sctp_init_ack_chunk_t))
+    /*
+     * There are optional parameters in the INIT ACK chunk
+     */
+    {
+      u16 pointer_offset = sizeof (sctp_init_ack_chunk_t);
+
+      while (pointer_offset < length)
+	{
+	  sctp_opt_params_hdr_t *opt_params_hdr =
+	    (sctp_opt_params_hdr_t *) ((char *) init_ack_chunk +
+				       pointer_offset);
+
+	  switch (clib_net_to_host_u16 (opt_params_hdr->type))
+	    {
+	    case SCTP_IPV4_ADDRESS_TYPE:
+	      {
+		sctp_ipv4_addr_param_t *ipv4 =
+		  (sctp_ipv4_addr_param_t *) opt_params_hdr;
+
+		sctp_sub_connection_add_ip4 (vlib_get_main (),
+					     &sctp_conn->sub_conn
+					     [SCTP_PRIMARY_PATH_IDX].connection.
+					     lcl_ip.ip4, &ipv4->address);
+
+		break;
+	      }
+	    case SCTP_IPV6_ADDRESS_TYPE:
+	      {
+		sctp_ipv6_addr_param_t *ipv6 =
+		  (sctp_ipv6_addr_param_t *) opt_params_hdr;
+
+		sctp_sub_connection_add_ip6 (vlib_get_main (),
+					     &sctp_conn->sub_conn
+					     [SCTP_PRIMARY_PATH_IDX].connection.
+					     lcl_ip.ip6, &ipv6->address);
+
+		break;
+	      }
+	    case SCTP_STATE_COOKIE_TYPE:
+	      {
+		sctp_state_cookie_param_t *state_cookie_param =
+		  (sctp_state_cookie_param_t *) opt_params_hdr;
+
+		clib_memcpy_fast (&(sctp_conn->cookie_param),
+				  state_cookie_param,
+				  sizeof (sctp_state_cookie_param_t));
+
+		break;
+	      }
+	    case SCTP_HOSTNAME_ADDRESS_TYPE:
+	      {
+		sctp_hostname_param_t *hostname_addr =
+		  (sctp_hostname_param_t *) opt_params_hdr;
+		clib_memcpy_fast (hostname, hostname_addr->hostname,
+				  FQDN_MAX_LENGTH);
+		break;
+	      }
+	    case SCTP_UNRECOGNIZED_TYPE:
+	      {
+		break;
+	      }
+	    }
+	  u16 increment = clib_net_to_host_u16 (opt_params_hdr->length);
+	  /* This indicates something really bad happened */
+	  if (increment == 0)
+	    {
+	      return SCTP_ERROR_INVALID_TAG;
+	    }
+	  pointer_offset += increment;
+	}
+    }
+
+  sctp_prepare_cookie_echo_chunk (sctp_conn, idx, b0, 1);
+
+  /* Start the T1_COOKIE timer */
+  sctp_timer_set (sctp_conn, idx,
+		  SCTP_TIMER_T1_COOKIE, sctp_conn->sub_conn[idx].RTO);
+
+  return SCTP_ERROR_NONE;
+}
+
+/** Enqueue data out-of-order for delivery to application */
+always_inline int
+sctp_session_enqueue_data_ooo (sctp_connection_t * sctp_conn,
+			       vlib_buffer_t * b, u16 data_len, u8 conn_idx)
+{
+  int written, error = SCTP_ERROR_ENQUEUED;
+
+  written =
+    session_enqueue_stream_connection (&sctp_conn->
+				       sub_conn[conn_idx].connection, b, 0,
+				       1 /* queue event */ ,
+				       0);
+
+  /* Update next_tsn_expected */
+  if (PREDICT_TRUE (written == data_len))
+    {
+      sctp_conn->next_tsn_expected += written;
+
+      SCTP_ADV_DBG ("CONN = %u, WRITTEN [%u] == DATA_LEN [%d]",
+		    sctp_conn->sub_conn[conn_idx].connection.c_index,
+		    written, data_len);
+    }
+  /* If more data written than expected, account for out-of-order bytes. */
+  else if (written > data_len)
+    {
+      sctp_conn->next_tsn_expected += written;
+
+      SCTP_ADV_DBG ("CONN = %u, WRITTEN [%u] > DATA_LEN [%d]",
+		    sctp_conn->sub_conn[conn_idx].connection.c_index,
+		    written, data_len);
+    }
+  else if (written > 0)
+    {
+      /* We've written something but FIFO is probably full now */
+      sctp_conn->next_tsn_expected += written;
+
+      error = SCTP_ERROR_PARTIALLY_ENQUEUED;
+
+      SCTP_ADV_DBG
+	("CONN = %u, WRITTEN [%u] > 0 (SCTP_ERROR_PARTIALLY_ENQUEUED)",
+	 sctp_conn->sub_conn[conn_idx].connection.c_index, written);
+    }
+  else
+    {
+      SCTP_ADV_DBG ("CONN = %u, WRITTEN == 0 (SCTP_ERROR_FIFO_FULL)",
+		    sctp_conn->sub_conn[conn_idx].connection.c_index);
+
+      return SCTP_ERROR_FIFO_FULL;
+    }
+
+  /* TODO: Update out_of_order_map & SACK list */
+
+  return error;
+}
+
+/** Enqueue data for delivery to application */
+always_inline int
+sctp_session_enqueue_data (sctp_connection_t * sctp_conn, vlib_buffer_t * b,
+			   u16 data_len, u8 conn_idx)
+{
+  int written, error = SCTP_ERROR_ENQUEUED;
+
+  written =
+    session_enqueue_stream_connection (&sctp_conn->
+				       sub_conn[conn_idx].connection, b, 0,
+				       1 /* queue event */ ,
+				       1);
+
+  /* Update next_tsn_expected */
+  if (PREDICT_TRUE (written == data_len))
+    {
+      sctp_conn->next_tsn_expected += written;
+
+      SCTP_ADV_DBG ("CONN = %u, WRITTEN [%u] == DATA_LEN [%d]",
+		    sctp_conn->sub_conn[conn_idx].connection.c_index,
+		    written, data_len);
+    }
+  /* If more data written than expected, account for out-of-order bytes. */
+  else if (written > data_len)
+    {
+      sctp_conn->next_tsn_expected += written;
+
+      SCTP_ADV_DBG ("CONN = %u, WRITTEN [%u] > DATA_LEN [%d]",
+		    sctp_conn->sub_conn[conn_idx].connection.c_index,
+		    written, data_len);
+    }
+  else if (written > 0)
+    {
+      /* We've written something but FIFO is probably full now */
+      sctp_conn->next_tsn_expected += written;
+
+      error = SCTP_ERROR_PARTIALLY_ENQUEUED;
+
+      SCTP_ADV_DBG
+	("CONN = %u, WRITTEN [%u] > 0 (SCTP_ERROR_PARTIALLY_ENQUEUED)",
+	 sctp_conn->sub_conn[conn_idx].connection.c_index, written);
+    }
+  else
+    {
+      SCTP_ADV_DBG ("CONN = %u, WRITTEN == 0 (SCTP_ERROR_FIFO_FULL)",
+		    sctp_conn->sub_conn[conn_idx].connection.c_index);
+
+      return SCTP_ERROR_FIFO_FULL;
+    }
+
+  return error;
+}
+
+always_inline u8
+sctp_is_sack_delayable (sctp_connection_t * sctp_conn, u8 idx, u8 is_gapping)
+{
+  if (sctp_conn->conn_config.never_delay_sack)
+    {
+      SCTP_CONN_TRACKING_DBG ("sctp_conn->conn_config.never_delay_sack = ON");
+      return 0;
+    }
+
+  /* Section 4.4 of the RFC4960 */
+  if (sctp_conn->state == SCTP_STATE_SHUTDOWN_SENT)
+    {
+      SCTP_CONN_TRACKING_DBG ("sctp_conn->state = %s; SACK not delayable",
+			      sctp_state_to_string (sctp_conn->state));
+      return 0;
+    }
+
+  if (is_gapping)
+    {
+      SCTP_CONN_TRACKING_DBG
+	("gapping != 0: CONN_INDEX = %u, sctp_conn->ack_state = %u",
+	 sctp_conn->sub_conn[idx].connection.c_index, sctp_conn->ack_state);
+      return 0;
+    }
+
+  sctp_conn->ack_state += 1;
+  if (sctp_conn->ack_state >= MAX_ENQUEABLE_SACKS)
+    {
+      SCTP_CONN_TRACKING_DBG
+	("sctp_conn->ack_state >= MAX_ENQUEABLE_SACKS: CONN_INDEX = %u, sctp_conn->ack_state = %u",
+	 sctp_conn->sub_conn[idx].connection.c_index, sctp_conn->ack_state);
+      return 0;
+    }
+
+  return 1;
+}
+
+always_inline void
+sctp_is_connection_gapping (sctp_connection_t * sctp_conn, u32 tsn,
+			    u8 * gapping)
+{
+  if (sctp_conn->next_tsn_expected != tsn)	// It means data transmission is GAPPING
+    {
+      SCTP_CONN_TRACKING_DBG
+	("GAPPING: CONN_INDEX = %u, sctp_conn->next_tsn_expected = %u, tsn = %u, diff = %u",
+	 sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.c_index,
+	 sctp_conn->next_tsn_expected, tsn,
+	 sctp_conn->next_tsn_expected - tsn);
+
+      *gapping = 1;
+    }
+}
+
+always_inline u16
+sctp_handle_data (sctp_payload_data_chunk_t * sctp_data_chunk,
+		  sctp_connection_t * sctp_conn, u8 idx, vlib_buffer_t * b,
+		  u16 * next0)
+{
+  u32 error = 0, n_data_bytes;
+  u8 is_gapping = 0;
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sctp_data_chunk->sctp_hdr.verification_tag)
+    {
+      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      sctp_conn->sub_conn[idx].enqueue_state = SCTP_ERROR_INVALID_TAG;
+      return sctp_conn->sub_conn[idx].enqueue_state;
+    }
+
+  sctp_buffer_opaque (b)->sctp.sid = sctp_data_chunk->stream_id;
+  sctp_buffer_opaque (b)->sctp.ssn = sctp_data_chunk->stream_seq;
+
+  u32 tsn = clib_net_to_host_u32 (sctp_data_chunk->tsn);
+
+  vlib_buffer_advance (b, sctp_buffer_opaque (b)->sctp.data_offset);
+  u32 chunk_len = vnet_sctp_get_chunk_length (&sctp_data_chunk->chunk_hdr) -
+    (sizeof (sctp_payload_data_chunk_t) - sizeof (sctp_header_t));
+
+  ASSERT (sctp_buffer_opaque (b)->sctp.data_len);
+  ASSERT (chunk_len);
+
+  /* Padding was added: see RFC 4096 section 3.3.1 */
+  if (sctp_buffer_opaque (b)->sctp.data_len > chunk_len)
+    {
+      /* Let's change the data_len to the right amount calculated here now.
+       * We cannot do that in the generic sctp46_input_dispatcher node since
+       * that is common to all CHUNKS handling.
+       */
+      sctp_buffer_opaque (b)->sctp.data_len = chunk_len;
+      /* We need to change b->current_length so that downstream calls to
+       * session_enqueue_stream_connection (called by sctp_session_enqueue_data)
+       * push the correct amount of data to be enqueued.
+       */
+      b->current_length = chunk_len;
+    }
+  n_data_bytes = sctp_buffer_opaque (b)->sctp.data_len;
+
+  sctp_is_connection_gapping (sctp_conn, tsn, &is_gapping);
+
+  sctp_conn->last_rcvd_tsn = tsn;
+
+  SCTP_ADV_DBG ("POINTER_WITH_DATA = %p", b->data);
+
+  u8 bbit = vnet_sctp_get_bbit (&sctp_data_chunk->chunk_hdr);
+  u8 ebit = vnet_sctp_get_ebit (&sctp_data_chunk->chunk_hdr);
+
+  if (bbit == 1 && ebit == 1)	/* Unfragmented message */
+    {
+      /* In order data, enqueue. Fifo figures out by itself if any out-of-order
+       * segments can be enqueued after fifo tail offset changes. */
+      if (PREDICT_FALSE (is_gapping == 1))
+	error =
+	  sctp_session_enqueue_data_ooo (sctp_conn, b, n_data_bytes, idx);
+      else
+	error = sctp_session_enqueue_data (sctp_conn, b, n_data_bytes, idx);
+    }
+  else if (bbit == 1 && ebit == 0)	/* First piece of a fragmented user message */
+    {
+      error = sctp_session_enqueue_data (sctp_conn, b, n_data_bytes, idx);
+    }
+  else if (bbit == 0 && ebit == 1)	/* Last piece of a fragmented user message */
+    {
+      if (PREDICT_FALSE (is_gapping == 1))
+	error =
+	  sctp_session_enqueue_data_ooo (sctp_conn, b, n_data_bytes, idx);
+      else
+	error = sctp_session_enqueue_data (sctp_conn, b, n_data_bytes, idx);
+    }
+  else				/* Middle piece of a fragmented user message */
+    {
+      if (PREDICT_FALSE (is_gapping == 1))
+	error =
+	  sctp_session_enqueue_data_ooo (sctp_conn, b, n_data_bytes, idx);
+      else
+	error = sctp_session_enqueue_data (sctp_conn, b, n_data_bytes, idx);
+    }
+  sctp_conn->last_rcvd_tsn = tsn;
+
+  SCTP_ADV_DBG ("POINTER_WITH_DATA = %p", b->data);
+
+  if (!sctp_is_sack_delayable (sctp_conn, idx, is_gapping))
+    {
+      *next0 = sctp_next_output (sctp_conn->sub_conn[idx].c_is_ip4);
+      sctp_prepare_sack_chunk (sctp_conn, idx, b);
+    }
+  else
+    *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+
+  sctp_conn->sub_conn[idx].enqueue_state = error;
+
+  return error;
+}
+
+always_inline u16
+sctp_handle_cookie_echo (sctp_header_t * sctp_hdr,
+			 sctp_chunks_common_hdr_t * sctp_chunk_hdr,
+			 sctp_connection_t * sctp_conn, u8 idx,
+			 vlib_buffer_t * b0, u16 * next0)
+{
+  u64 now = sctp_time_now ();
+
+  sctp_cookie_echo_chunk_t *cookie_echo =
+    (sctp_cookie_echo_chunk_t *) sctp_hdr;
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
+    {
+      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  sctp_calculate_rto (sctp_conn, idx);
+
+  u64 creation_time =
+    clib_net_to_host_u64 (cookie_echo->cookie.creation_time);
+  u64 cookie_lifespan =
+    clib_net_to_host_u32 (cookie_echo->cookie.cookie_lifespan);
+
+  if (now > creation_time + cookie_lifespan)
+    {
+      SCTP_DBG ("now (%u) > creation_time (%u) + cookie_lifespan (%u)",
+		now, creation_time, cookie_lifespan);
+      return SCTP_ERROR_COOKIE_ECHO_VIOLATION;
+    }
+
+  sctp_prepare_cookie_ack_chunk (sctp_conn, idx, b0);
+
+  /* Change state */
+  sctp_conn->state = SCTP_STATE_ESTABLISHED;
+  sctp_conn->sub_conn[idx].state = SCTP_SUBCONN_STATE_UP;
+  *next0 = sctp_next_output (sctp_conn->sub_conn[idx].c_is_ip4);
+
+  sctp_timer_set (sctp_conn, idx, SCTP_TIMER_T4_HEARTBEAT,
+		  sctp_conn->sub_conn[idx].RTO);
+
+  session_stream_accept_notify (&sctp_conn->sub_conn[idx].connection);
+
+  return SCTP_ERROR_NONE;
+
+}
+
+always_inline u16
+sctp_handle_cookie_ack (sctp_header_t * sctp_hdr,
+			sctp_chunks_common_hdr_t * sctp_chunk_hdr,
+			sctp_connection_t * sctp_conn, u8 idx,
+			vlib_buffer_t * b0, u16 * next0)
+{
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
+    {
+      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  sctp_calculate_rto (sctp_conn, idx);
+
+  sctp_timer_reset (sctp_conn, idx, SCTP_TIMER_T1_COOKIE);
+  /* Change state */
+  sctp_conn->state = SCTP_STATE_ESTABLISHED;
+  sctp_conn->sub_conn[idx].state = SCTP_SUBCONN_STATE_UP;
+
+  *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+
+  sctp_timer_set (sctp_conn, idx, SCTP_TIMER_T4_HEARTBEAT,
+		  sctp_conn->sub_conn[idx].RTO);
+
+  session_stream_accept_notify (&sctp_conn->sub_conn[idx].connection);
+
+  return SCTP_ERROR_NONE;
+
+}
+
+always_inline uword
+sctp46_rcv_phase_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
+			 vlib_frame_t * from_frame, int is_ip4)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+
+  u32 n_left_from, next_index, *from, *to_next;
+  u32 my_thread_index = vm->thread_index;
+
+  from = vlib_frame_vector_args (from_frame);
+  n_left_from = from_frame->n_vectors;
+
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  sctp_header_t *sctp_hdr = 0;
+	  sctp_chunks_common_hdr_t *sctp_chunk_hdr = 0;
+	  ip4_header_t *ip4_hdr = 0;
+	  ip6_header_t *ip6_hdr = 0;
+	  sctp_connection_t *sctp_conn, *new_sctp_conn;
+	  u16 sctp_implied_length = 0;
+	  u16 error0 = SCTP_ERROR_NONE, next0 = sctp_next_drop (is_ip4);
+	  u8 idx;
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+
+	  /* If we are in SCTP_COOKIE_WAIT_STATE then the connection
+	   * will come from the half-open connections pool.
+	   */
+	  sctp_conn =
+	    sctp_half_open_connection_get (sctp_buffer_opaque (b0)->
+					   sctp.connection_index);
+
+	  if (PREDICT_FALSE (sctp_conn == 0))
+	    {
+	      SCTP_ADV_DBG
+		("sctp_conn == NULL; return SCTP_ERROR_INVALID_CONNECTION");
+	      error0 = SCTP_ERROR_INVALID_CONNECTION;
+	      goto drop;
+	    }
+	  if (is_ip4)
+	    {
+	      ip4_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip4_next_header (ip4_hdr);
+	      idx = sctp_sub_conn_id_via_ip4h (sctp_conn, ip4_hdr);
+	    }
+	  else
+	    {
+	      ip6_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip6_next_header (ip6_hdr);
+	      idx = sctp_sub_conn_id_via_ip6h (sctp_conn, ip6_hdr);
+	    }
+
+	  sctp_conn->sub_conn[idx].subconn_idx = idx;
+	  sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
+
+	  sctp_chunk_hdr =
+	    (sctp_chunks_common_hdr_t *) (&full_hdr->common_hdr);
+
+	  sctp_implied_length =
+	    sctp_calculate_implied_length (ip4_hdr, ip6_hdr, is_ip4);
+
+	  u8 chunk_type = vnet_sctp_get_chunk_type (&full_hdr->common_hdr);
+
+	  switch (chunk_type)
+	    {
+	    case INIT_ACK:
+	      error0 =
+		sctp_is_valid_init_ack (sctp_hdr, sctp_chunk_hdr, sctp_conn,
+					b0, sctp_implied_length);
+
+	      if (error0 == SCTP_ERROR_NONE)
+		{
+		  pool_get (tm->connections[my_thread_index], new_sctp_conn);
+		  clib_memcpy_fast (new_sctp_conn, sctp_conn,
+				    sizeof (*new_sctp_conn));
+		  new_sctp_conn->sub_conn[idx].c_c_index =
+		    new_sctp_conn - tm->connections[my_thread_index];
+		  new_sctp_conn->sub_conn[idx].c_thread_index =
+		    my_thread_index;
+		  new_sctp_conn->sub_conn[idx].PMTU =
+		    sctp_conn->sub_conn[idx].PMTU;
+		  new_sctp_conn->sub_conn[idx].subconn_idx = idx;
+
+		  if (sctp_half_open_connection_cleanup (sctp_conn))
+		    {
+		      SCTP_DBG
+			("Cannot cleanup half-open connection; not the owning thread");
+		    }
+
+		  sctp_connection_timers_init (new_sctp_conn);
+
+		  sctp_init_cwnd (new_sctp_conn);
+
+		  error0 =
+		    sctp_handle_init_ack (sctp_hdr, sctp_chunk_hdr,
+					  new_sctp_conn, idx, b0,
+					  sctp_implied_length);
+
+		  if (session_stream_connect_notify
+		      (&new_sctp_conn->sub_conn[idx].connection, 0))
+		    {
+		      SCTP_DBG
+			("conn_index = %u: session_stream_connect_notify error; cleaning up connection",
+			 new_sctp_conn->sub_conn[idx].connection.c_index);
+		      sctp_connection_cleanup (new_sctp_conn);
+		      goto drop;
+		    }
+		  next0 = sctp_next_output (is_ip4);
+		}
+	      break;
+
+	    case OPERATION_ERROR:
+	      error0 =
+		sctp_handle_operation_err (sctp_hdr, sctp_conn, idx, b0,
+					   &next0);
+	      break;
+
+	      /* All UNEXPECTED scenarios (wrong chunk received per state-machine)
+	       * are handled by the input-dispatcher function using the table-lookup
+	       * hence we should never get to the "default" case below.
+	       */
+	    default:
+	      error0 = SCTP_ERROR_UNKNOWN_CHUNK;
+	      next0 = sctp_next_drop (is_ip4);
+	      goto drop;
+	    }
+
+	  if (error0 != SCTP_ERROR_NONE)
+	    {
+	      clib_warning ("error while parsing chunk");
+	      sctp_connection_cleanup (sctp_conn);
+	      next0 = sctp_next_drop (is_ip4);
+	      goto drop;
+	    }
+
+	drop:
+	  b0->error = node->errors[error0];
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      sctp_rx_trace_t *t0 =
+		vlib_add_trace (vm, node, b0, sizeof (*t0));
+	      sctp_set_rx_trace_data (t0, sctp_conn, sctp_hdr, b0, is_ip4);
+	    }
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+  return from_frame->n_vectors;
+}
+
+VLIB_NODE_FN (sctp4_rcv_phase_node) (vlib_main_t * vm,
+				     vlib_node_runtime_t * node,
+				     vlib_frame_t * from_frame)
+{
+  return sctp46_rcv_phase_inline (vm, node, from_frame, 1 /* is_ip4 */ );
+}
+
+VLIB_NODE_FN (sctp6_init_phase_node) (vlib_main_t * vm,
+				      vlib_node_runtime_t * node,
+				      vlib_frame_t * from_frame)
+{
+  return sctp46_rcv_phase_inline (vm, node, from_frame, 0 /* is_ip4 */ );
+}
+
+static u8 *
+format_sctp_rx_trace_short (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  sctp_rx_trace_t *t = va_arg (*args, sctp_rx_trace_t *);
+
+  s = format (s, "%d -> %d (%U)",
+	      clib_net_to_host_u16 (t->sctp_header.src_port),
+	      clib_net_to_host_u16 (t->sctp_header.dst_port),
+	      format_sctp_state, t->sctp_connection.state);
+
+  return s;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp4_rcv_phase_node) =
+{
+  .name = "sctp4-rcv",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_RCV_PHASE_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_RCV_PHASE_NEXT_##s] = n,
+    foreach_sctp_state_next
+#undef _
+  },
+  .format_trace = format_sctp_rx_trace_short,
+};
+/* *INDENT-ON* */
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp6_init_phase_node) =
+{
+  .name = "sctp6-rcv",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_RCV_PHASE_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_RCV_PHASE_NEXT_##s] = n,
+    foreach_sctp_state_next
+#undef _
+  },
+  .format_trace = format_sctp_rx_trace_short,
+};
+/* *INDENT-ON* */
+
+always_inline u16
+sctp_handle_shutdown (sctp_header_t * sctp_hdr,
+		      sctp_chunks_common_hdr_t * sctp_chunk_hdr,
+		      sctp_connection_t * sctp_conn, u8 idx,
+		      vlib_buffer_t * b0, u16 sctp_implied_length,
+		      u16 * next0)
+{
+  sctp_shutdown_association_chunk_t *shutdown_chunk =
+    (sctp_shutdown_association_chunk_t *) (sctp_hdr);
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
+    {
+      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  /*
+   * It is not possible to bundle any other CHUNK with the SHUTDOWN chunk
+   */
+  if (sctp_is_bundling (sctp_implied_length, &shutdown_chunk->chunk_hdr))
+    return SCTP_ERROR_BUNDLING_VIOLATION;
+
+  switch (sctp_conn->state)
+    {
+    case SCTP_STATE_ESTABLISHED:
+      if (sctp_check_outstanding_data_chunks (sctp_conn) == 0)
+	sctp_conn->state = SCTP_STATE_SHUTDOWN_RECEIVED;
+      sctp_send_shutdown_ack (sctp_conn, idx, b0);
+      break;
+
+    case SCTP_STATE_SHUTDOWN_SENT:
+      sctp_send_shutdown_ack (sctp_conn, idx, b0);
+      break;
+    }
+
+  *next0 = sctp_next_output (sctp_conn->sub_conn[idx].c_is_ip4);
+
+  return SCTP_ERROR_NONE;
+}
+
+always_inline u16
+sctp_handle_shutdown_ack (sctp_header_t * sctp_hdr,
+			  sctp_chunks_common_hdr_t * sctp_chunk_hdr,
+			  sctp_connection_t * sctp_conn, u8 idx,
+			  vlib_buffer_t * b0, u16 sctp_implied_length,
+			  u16 * next0)
+{
+  sctp_shutdown_ack_chunk_t *shutdown_ack_chunk =
+    (sctp_shutdown_ack_chunk_t *) (sctp_hdr);
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
+    {
+      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  /*
+   * It is not possible to bundle any other CHUNK with the SHUTDOWN chunk
+   */
+  if (sctp_is_bundling (sctp_implied_length, &shutdown_ack_chunk->chunk_hdr))
+    return SCTP_ERROR_BUNDLING_VIOLATION;
+
+  /* Whether we are in SCTP_STATE_SHUTDOWN_SENT or SCTP_STATE_SHUTDOWN_ACK_SENT
+   * the reception of a SHUTDOWN_ACK chunk leads to the same actions:
+   * - STOP T2_SHUTDOWN timer
+   * - SEND SHUTDOWN_COMPLETE chunk
+   */
+  sctp_timer_reset (sctp_conn, SCTP_PRIMARY_PATH_IDX, SCTP_TIMER_T2_SHUTDOWN);
+
+  sctp_send_shutdown_complete (sctp_conn, idx, b0);
+
+  *next0 = sctp_next_output (sctp_conn->sub_conn[idx].c_is_ip4);
+
+  return SCTP_ERROR_NONE;
+}
+
+always_inline u16
+sctp_handle_shutdown_complete (sctp_header_t * sctp_hdr,
+			       sctp_chunks_common_hdr_t * sctp_chunk_hdr,
+			       sctp_connection_t * sctp_conn, u8 idx,
+			       vlib_buffer_t * b0, u16 sctp_implied_length,
+			       u16 * next0)
+{
+  sctp_shutdown_complete_chunk_t *shutdown_complete =
+    (sctp_shutdown_complete_chunk_t *) (sctp_hdr);
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
+    {
+      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  /*
+   * It is not possible to bundle any other CHUNK with the SHUTDOWN chunk
+   */
+  if (sctp_is_bundling (sctp_implied_length, &shutdown_complete->chunk_hdr))
+    return SCTP_ERROR_BUNDLING_VIOLATION;
+
+  sctp_timer_reset (sctp_conn, idx, SCTP_TIMER_T2_SHUTDOWN);
+
+  session_transport_closing_notify (&sctp_conn->sub_conn[idx].connection);
+
+  sctp_conn->state = SCTP_STATE_CLOSED;
+
+  *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+
+  return SCTP_ERROR_NONE;
+}
+
+always_inline uword
+sctp46_shutdown_phase_inline (vlib_main_t * vm,
+			      vlib_node_runtime_t * node,
+			      vlib_frame_t * from_frame, int is_ip4)
+{
+  u32 n_left_from, next_index, *from, *to_next;
+  u32 my_thread_index = vm->thread_index;
+
+  from = vlib_frame_vector_args (from_frame);
+  n_left_from = from_frame->n_vectors;
+
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  sctp_rx_trace_t *sctp_trace;
+	  sctp_header_t *sctp_hdr = 0;
+	  sctp_chunks_common_hdr_t *sctp_chunk_hdr = 0;
+	  ip4_header_t *ip4_hdr = 0;
+	  ip6_header_t *ip6_hdr = 0;
+	  sctp_connection_t *sctp_conn;
+	  u16 sctp_implied_length = 0;
+	  u16 error0 = SCTP_ERROR_NONE, next0 = SCTP_RCV_PHASE_N_NEXT;
+	  u8 idx = 0;
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  sctp_conn =
+	    sctp_connection_get (sctp_buffer_opaque (b0)->
+				 sctp.connection_index, my_thread_index);
+
+	  if (PREDICT_FALSE (sctp_conn == 0))
+	    {
+	      SCTP_DBG
+		("sctp_conn == NULL; return SCTP_ERROR_INVALID_CONNECTION");
+	      error0 = SCTP_ERROR_INVALID_CONNECTION;
+	      goto drop;
+	    }
+
+	  if (is_ip4)
+	    {
+	      ip4_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip4_next_header (ip4_hdr);
+	      idx = sctp_sub_conn_id_via_ip4h (sctp_conn, ip4_hdr);
+	    }
+	  else
+	    {
+	      ip6_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip6_next_header (ip6_hdr);
+	      idx = sctp_sub_conn_id_via_ip6h (sctp_conn, ip6_hdr);
+	    }
+
+	  sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
+	  sctp_chunk_hdr = &full_hdr->common_hdr;
+
+	  sctp_implied_length =
+	    sctp_calculate_implied_length (ip4_hdr, ip6_hdr, is_ip4);
+
+	  u8 chunk_type = vnet_sctp_get_chunk_type (sctp_chunk_hdr);
+	  switch (chunk_type)
+	    {
+	    case SHUTDOWN:
+	      error0 =
+		sctp_handle_shutdown (sctp_hdr, sctp_chunk_hdr, sctp_conn,
+				      idx, b0, sctp_implied_length, &next0);
+	      break;
+
+	    case SHUTDOWN_ACK:
+	      error0 =
+		sctp_handle_shutdown_ack (sctp_hdr, sctp_chunk_hdr, sctp_conn,
+					  idx, b0, sctp_implied_length,
+					  &next0);
+	      break;
+
+	    case SHUTDOWN_COMPLETE:
+	      error0 =
+		sctp_handle_shutdown_complete (sctp_hdr, sctp_chunk_hdr,
+					       sctp_conn, idx, b0,
+					       sctp_implied_length, &next0);
+
+	      sctp_connection_cleanup (sctp_conn);
+	      break;
+
+	      /*
+	       * DATA chunks can still be transmitted/received in the SHUTDOWN-PENDING
+	       * and SHUTDOWN-SENT states (as per RFC4960 Section 6)
+	       */
+	    case DATA:
+	      error0 =
+		sctp_handle_data ((sctp_payload_data_chunk_t *) sctp_hdr,
+				  sctp_conn, idx, b0, &next0);
+	      break;
+
+	    case OPERATION_ERROR:
+	      error0 =
+		sctp_handle_operation_err (sctp_hdr, sctp_conn, idx, b0,
+					   &next0);
+	      break;
+
+	    case COOKIE_ECHO:	/* Cookie Received While Shutting Down */
+	      sctp_prepare_operation_error (sctp_conn, idx, b0,
+					    COOKIE_RECEIVED_WHILE_SHUTTING_DOWN);
+	      error0 = SCTP_ERROR_NONE;
+	      next0 = sctp_next_output (is_ip4);
+	      break;
+	      /* All UNEXPECTED scenarios (wrong chunk received per state-machine)
+	       * are handled by the input-dispatcher function using the table-lookup
+	       * hence we should never get to the "default" case below.
+	       */
+	    default:
+	      error0 = SCTP_ERROR_UNKNOWN_CHUNK;
+	      next0 = sctp_next_drop (is_ip4);
+	      goto drop;
+	    }
+
+	  if (error0 != SCTP_ERROR_NONE)
+	    {
+	      clib_warning ("error while parsing chunk");
+	      sctp_connection_cleanup (sctp_conn);
+	      next0 = sctp_next_drop (is_ip4);
+	      goto drop;
+	    }
+
+	drop:
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      sctp_trace =
+		vlib_add_trace (vm, node, b0, sizeof (*sctp_trace));
+
+	      if (sctp_hdr != NULL)
+		clib_memcpy_fast (&sctp_trace->sctp_header, sctp_hdr,
+				  sizeof (sctp_trace->sctp_header));
+
+	      if (sctp_conn != NULL)
+		clib_memcpy_fast (&sctp_trace->sctp_connection, sctp_conn,
+				  sizeof (sctp_trace->sctp_connection));
+	    }
+
+	  b0->error = node->errors[error0];
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  return from_frame->n_vectors;
+
+}
+
+VLIB_NODE_FN (sctp4_shutdown_phase_node) (vlib_main_t * vm,
+					  vlib_node_runtime_t * node,
+					  vlib_frame_t * from_frame)
+{
+  return sctp46_shutdown_phase_inline (vm, node, from_frame, 1 /* is_ip4 */ );
+}
+
+VLIB_NODE_FN (sctp6_shutdown_phase_node) (vlib_main_t * vm,
+					  vlib_node_runtime_t * node,
+					  vlib_frame_t * from_frame)
+{
+  return sctp46_shutdown_phase_inline (vm, node, from_frame, 1 /* is_ip4 */ );
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp4_shutdown_phase_node) =
+{
+  .name = "sctp4-shutdown",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_SHUTDOWN_PHASE_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_SHUTDOWN_PHASE_NEXT_##s] = n,
+    foreach_sctp_state_next
+#undef _
+  },
+  .format_trace = format_sctp_rx_trace_short,
+};
+/* *INDENT-ON* */
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp6_shutdown_phase_node) =
+{
+  .name = "sctp6-shutdown",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_SHUTDOWN_PHASE_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_SHUTDOWN_PHASE_NEXT_##s] = n,
+    foreach_sctp_state_next
+#undef _
+  },
+  .format_trace = format_sctp_rx_trace_short,
+};
+/* *INDENT-ON* */
+
+always_inline u16
+sctp_handle_sack (sctp_selective_ack_chunk_t * sack_chunk,
+		  sctp_connection_t * sctp_conn, u8 idx, vlib_buffer_t * b0,
+		  u16 * next0)
+{
+
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sack_chunk->sctp_hdr.verification_tag)
+    {
+      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  sctp_conn->sub_conn[idx].state = SCTP_SUBCONN_SACK_RECEIVED;
+
+  sctp_conn->sub_conn[idx].last_seen = sctp_time_now ();
+
+  /* Section 7.2.2; point (2) */
+  if (sctp_conn->sub_conn[idx].cwnd > sctp_conn->sub_conn[idx].ssthresh)
+    sctp_conn->sub_conn[idx].partially_acked_bytes =
+      sctp_conn->next_tsn - sack_chunk->cumulative_tsn_ack;
+
+  /* Section 7.2.2; point (5) */
+  if (sctp_conn->next_tsn - sack_chunk->cumulative_tsn_ack == 0)
+    sctp_conn->sub_conn[idx].partially_acked_bytes = 0;
+
+  sctp_conn->last_unacked_tsn = sack_chunk->cumulative_tsn_ack;
+
+  sctp_calculate_rto (sctp_conn, idx);
+
+  sctp_timer_update (sctp_conn, idx, SCTP_TIMER_T3_RXTX,
+		     sctp_conn->sub_conn[idx].RTO);
+
+  sctp_conn->sub_conn[idx].RTO_pending = 0;
+
+  *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+
+  return SCTP_ERROR_NONE;
+}
+
+always_inline u16
+sctp_handle_heartbeat (sctp_hb_req_chunk_t * sctp_hb_chunk,
+		       sctp_connection_t * sctp_conn, u8 idx,
+		       vlib_buffer_t * b0, u16 * next0)
+{
+  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
+  if (sctp_conn->local_tag != sctp_hb_chunk->sctp_hdr.verification_tag)
+    {
+      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+      return SCTP_ERROR_INVALID_TAG;
+    }
+
+  sctp_prepare_heartbeat_ack_chunk (sctp_conn, idx, b0);
+
+  *next0 = sctp_next_output (sctp_conn->sub_conn[idx].connection.is_ip4);
+
+  return SCTP_ERROR_NONE;
+}
+
+always_inline u16
+sctp_handle_heartbeat_ack (sctp_hb_ack_chunk_t * sctp_hb_ack_chunk,
+			   sctp_connection_t * sctp_conn, u8 idx,
+			   vlib_buffer_t * b0, u16 * next0)
+{
+  sctp_conn->sub_conn[idx].last_seen = sctp_time_now ();
+
+  sctp_conn->sub_conn[idx].unacknowledged_hb -= 1;
+
+  sctp_timer_update (sctp_conn, idx, SCTP_TIMER_T4_HEARTBEAT,
+		     sctp_conn->sub_conn[idx].RTO);
+
+  *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
+
+  return SCTP_ERROR_NONE;
+}
+
+always_inline void
+sctp_node_inc_counter (vlib_main_t * vm, u32 sctp4_node, u32 sctp6_node,
+		       u8 is_ip4, u8 evt, u8 val)
+{
+  if (PREDICT_TRUE (!val))
+    return;
+
+  if (is_ip4)
+    vlib_node_increment_counter (vm, sctp4_node, evt, val);
+  else
+    vlib_node_increment_counter (vm, sctp6_node, evt, val);
+}
+
+always_inline uword
+sctp46_listen_process_inline (vlib_main_t * vm,
+			      vlib_node_runtime_t * node,
+			      vlib_frame_t * from_frame, int is_ip4)
+{
+  u32 n_left_from, next_index, *from, *to_next;
+  u32 my_thread_index = vm->thread_index;
+
+  from = vlib_frame_vector_args (from_frame);
+  n_left_from = from_frame->n_vectors;
+
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  sctp_header_t *sctp_hdr = 0;
+	  ip4_header_t *ip4_hdr;
+	  ip6_header_t *ip6_hdr;
+	  sctp_connection_t *child_conn;
+	  sctp_connection_t *sctp_listener;
+	  u16 next0 = sctp_next_drop (is_ip4), error0 = SCTP_ERROR_ENQUEUED;
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  sctp_listener =
+	    sctp_listener_get (sctp_buffer_opaque (b0)->
+			       sctp.connection_index);
+
+	  if (is_ip4)
+	    {
+	      ip4_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip4_next_header (ip4_hdr);
+	    }
+	  else
+	    {
+	      ip6_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip6_next_header (ip6_hdr);
+	    }
+
+	  child_conn =
+	    sctp_lookup_connection (sctp_listener->sub_conn
+				    [SCTP_PRIMARY_PATH_IDX].c_fib_index, b0,
+				    my_thread_index, is_ip4);
+
+	  if (PREDICT_FALSE (child_conn->state != SCTP_STATE_CLOSED))
+	    {
+	      SCTP_DBG
+		("conn_index = %u: child_conn->state != SCTP_STATE_CLOSED.... STATE=%s",
+		 child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].
+		 connection.c_index,
+		 sctp_state_to_string (child_conn->state));
+	      error0 = SCTP_ERROR_CREATE_EXISTS;
+	      goto drop;
+	    }
+
+	  /* Create child session and send SYN-ACK */
+	  child_conn = sctp_connection_new (my_thread_index);
+	  child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].subconn_idx =
+	    SCTP_PRIMARY_PATH_IDX;
+	  child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_lcl_port =
+	    sctp_hdr->dst_port;
+	  child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_rmt_port =
+	    sctp_hdr->src_port;
+	  child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_is_ip4 = is_ip4;
+	  child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.proto =
+	    sctp_listener->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.proto;
+	  child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].PMTU =
+	    sctp_listener->sub_conn[SCTP_PRIMARY_PATH_IDX].PMTU;
+	  child_conn->state = SCTP_STATE_CLOSED;
+	  child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.fib_index =
+	    sctp_listener->sub_conn[SCTP_PRIMARY_PATH_IDX].
+	    connection.fib_index;
+
+	  if (is_ip4)
+	    {
+	      child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_lcl_ip4.as_u32 =
+		ip4_hdr->dst_address.as_u32;
+	      child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_rmt_ip4.as_u32 =
+		ip4_hdr->src_address.as_u32;
+	    }
+	  else
+	    {
+	      clib_memcpy_fast (&child_conn->
+				sub_conn[SCTP_PRIMARY_PATH_IDX].c_lcl_ip6,
+				&ip6_hdr->dst_address,
+				sizeof (ip6_address_t));
+	      clib_memcpy_fast (&child_conn->
+				sub_conn[SCTP_PRIMARY_PATH_IDX].c_rmt_ip6,
+				&ip6_hdr->src_address,
+				sizeof (ip6_address_t));
+	    }
+
+	  sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
+	  sctp_chunks_common_hdr_t *sctp_chunk_hdr = &full_hdr->common_hdr;
+
+	  u8 chunk_type = vnet_sctp_get_chunk_type (sctp_chunk_hdr);
+	  if (chunk_type != INIT && chunk_type != DATA
+	      && chunk_type != OPERATION_ERROR)
+	    {
+	      SCTP_DBG
+		("conn_index = %u: chunk_type != INIT... chunk_type=%s",
+		 child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].
+		 connection.c_index, sctp_chunk_to_string (chunk_type));
+
+	      error0 = SCTP_ERROR_UNKNOWN_CHUNK;
+	      next0 = sctp_next_drop (is_ip4);
+	      goto drop;
+	    }
+
+	  u16 sctp_implied_length =
+	    sctp_calculate_implied_length (ip4_hdr, ip6_hdr, is_ip4);
+
+	  switch (chunk_type)
+	    {
+	    case INIT:
+	      sctp_connection_timers_init (child_conn);
+
+	      sctp_init_snd_vars (child_conn);
+
+	      sctp_init_cwnd (child_conn);
+
+	      error0 =
+		sctp_handle_init (sctp_hdr, sctp_chunk_hdr, child_conn, b0,
+				  sctp_implied_length);
+
+	      if (error0 == SCTP_ERROR_NONE)
+		{
+		  if (session_stream_accept
+		      (&child_conn->
+		       sub_conn[SCTP_PRIMARY_PATH_IDX].connection,
+		       sctp_listener->
+		       sub_conn[SCTP_PRIMARY_PATH_IDX].c_s_index,
+		       sctp_listener->
+		       sub_conn[SCTP_PRIMARY_PATH_IDX].c_thread_index, 0))
+		    {
+		      clib_warning ("session accept fail");
+		      sctp_connection_cleanup (child_conn);
+		      error0 = SCTP_ERROR_CREATE_SESSION_FAIL;
+		      goto drop;
+		    }
+		  next0 = sctp_next_output (is_ip4);
+		}
+	      break;
+
+	      /* Reception of a DATA chunk whilst in the CLOSED state is called
+	       * "Out of the Blue" packet and handling of the chunk needs special treatment
+	       * as per RFC4960 section 8.4
+	       */
+	    case DATA:
+	      break;
+
+	    case OPERATION_ERROR:
+	      error0 =
+		sctp_handle_operation_err (sctp_hdr, child_conn,
+					   SCTP_PRIMARY_PATH_IDX, b0, &next0);
+	      break;
+	    }
+
+	drop:
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      sctp_rx_trace_t *t0 =
+		vlib_add_trace (vm, node, b0, sizeof (*t0));
+	      clib_memcpy_fast (&t0->sctp_header, sctp_hdr,
+				sizeof (t0->sctp_header));
+	      clib_memcpy_fast (&t0->sctp_connection, sctp_listener,
+				sizeof (t0->sctp_connection));
+	    }
+
+	  b0->error = node->errors[error0];
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi0, next0);
+	}
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+
+    }
+  return from_frame->n_vectors;
+}
+
+VLIB_NODE_FN (sctp4_listen_phase_node) (vlib_main_t * vm,
+					vlib_node_runtime_t * node,
+					vlib_frame_t * from_frame)
+{
+  return sctp46_listen_process_inline (vm, node, from_frame, 1 /* is_ip4 */ );
+}
+
+VLIB_NODE_FN (sctp6_listen_phase_node) (vlib_main_t * vm,
+					vlib_node_runtime_t * node,
+					vlib_frame_t * from_frame)
+{
+  return sctp46_listen_process_inline (vm, node, from_frame, 0 /* is_ip4 */ );
+}
+
+always_inline uword
+sctp46_established_phase_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
+				 vlib_frame_t * from_frame, int is_ip4)
+{
+  sctp_main_t *sm = vnet_get_sctp_main ();
+  u32 n_left_from, next_index, *from, *to_next;
+  u32 my_thread_index = vm->thread_index, errors = 0;
+
+  from = vlib_frame_vector_args (from_frame);
+  n_left_from = from_frame->n_vectors;
+
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  sctp_header_t *sctp_hdr = 0;
+	  sctp_chunks_common_hdr_t *sctp_chunk_hdr = 0;
+	  ip4_header_t *ip4_hdr = 0;
+	  ip6_header_t *ip6_hdr = 0;
+	  sctp_connection_t *sctp_conn;
+	  u16 error0 = SCTP_ERROR_ENQUEUED, next0 =
+	    SCTP_ESTABLISHED_PHASE_N_NEXT;
+	  u8 idx;
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  sctp_conn =
+	    sctp_connection_get (sctp_buffer_opaque (b0)->
+				 sctp.connection_index, my_thread_index);
+
+	  if (PREDICT_FALSE (sctp_conn == 0))
+	    {
+	      SCTP_DBG
+		("sctp_conn == NULL; return SCTP_ERROR_INVALID_CONNECTION");
+	      error0 = SCTP_ERROR_INVALID_CONNECTION;
+	      goto done;
+	    }
+	  if (is_ip4)
+	    {
+	      ip4_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip4_next_header (ip4_hdr);
+	      idx = sctp_sub_conn_id_via_ip4h (sctp_conn, ip4_hdr);
+	    }
+	  else
+	    {
+	      ip6_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip6_next_header (ip6_hdr);
+	      idx = sctp_sub_conn_id_via_ip6h (sctp_conn, ip6_hdr);
+	    }
+
+	  sctp_conn->sub_conn[idx].subconn_idx = idx;
+
+	  sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
+	  sctp_chunk_hdr =
+	    (sctp_chunks_common_hdr_t *) (&full_hdr->common_hdr);
+
+	  u8 chunk_type = vnet_sctp_get_chunk_type (&full_hdr->common_hdr);
+
+	  switch (chunk_type)
+	    {
+	    case COOKIE_ECHO:
+	      error0 =
+		sctp_handle_cookie_echo (sctp_hdr, sctp_chunk_hdr, sctp_conn,
+					 idx, b0, &next0);
+	      break;
+
+	    case COOKIE_ACK:
+	      error0 =
+		sctp_handle_cookie_ack (sctp_hdr, sctp_chunk_hdr, sctp_conn,
+					idx, b0, &next0);
+	      break;
+
+	    case SACK:
+	      error0 =
+		sctp_handle_sack ((sctp_selective_ack_chunk_t *) sctp_hdr,
+				  sctp_conn, idx, b0, &next0);
+	      break;
+
+	    case HEARTBEAT:
+	      error0 =
+		sctp_handle_heartbeat ((sctp_hb_req_chunk_t *) sctp_hdr,
+				       sctp_conn, idx, b0, &next0);
+	      break;
+
+	    case HEARTBEAT_ACK:
+	      error0 =
+		sctp_handle_heartbeat_ack ((sctp_hb_ack_chunk_t *) sctp_hdr,
+					   sctp_conn, idx, b0, &next0);
+	      break;
+
+	    case DATA:
+	      error0 =
+		sctp_handle_data ((sctp_payload_data_chunk_t *) sctp_hdr,
+				  sctp_conn, idx, b0, &next0);
+	      break;
+
+	    case OPERATION_ERROR:
+	      error0 =
+		sctp_handle_operation_err (sctp_hdr, sctp_conn, idx, b0,
+					   &next0);
+	      break;
+
+	      /* All UNEXPECTED scenarios (wrong chunk received per state-machine)
+	       * are handled by the input-dispatcher function using the table-lookup
+	       * hence we should never get to the "default" case below.
+	       */
+	    default:
+	      error0 = SCTP_ERROR_UNKNOWN_CHUNK;
+	      next0 = sctp_next_drop (is_ip4);
+	      goto done;
+	    }
+
+	done:
+	  b0->error = node->errors[error0];
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      sctp_rx_trace_t *t0 =
+		vlib_add_trace (vm, node, b0, sizeof (*t0));
+	      sctp_set_rx_trace_data (t0, sctp_conn, sctp_hdr, b0, is_ip4);
+	    }
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  errors = session_main_flush_enqueue_events (TRANSPORT_PROTO_SCTP,
+					      my_thread_index);
+
+  sctp_node_inc_counter (vm, is_ip4, sm->sctp4_established_phase_node_index,
+			 sm->sctp6_established_phase_node_index,
+			 SCTP_ERROR_EVENT_FIFO_FULL, errors);
+  sctp_flush_frame_to_output (vm, my_thread_index, is_ip4);
+
+  return from_frame->n_vectors;
+}
+
+VLIB_NODE_FN (sctp4_established_phase_node) (vlib_main_t * vm,
+					     vlib_node_runtime_t * node,
+					     vlib_frame_t * from_frame)
+{
+  return sctp46_established_phase_inline (vm, node, from_frame,
+					  1 /* is_ip4 */ );
+}
+
+VLIB_NODE_FN (sctp6_established_phase_node) (vlib_main_t * vm,
+					     vlib_node_runtime_t * node,
+					     vlib_frame_t * from_frame)
+{
+  return sctp46_established_phase_inline (vm, node, from_frame,
+					  0 /* is_ip4 */ );
+}
+
+static u8 *
+format_sctp_rx_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  sctp_rx_trace_t *t = va_arg (*args, sctp_rx_trace_t *);
+  u32 indent = format_get_indent (s);
+
+  s = format (s, "%U\n%U%U",
+	      format_sctp_header, &t->sctp_header, 128,
+	      format_white_space, indent,
+	      format_sctp_connection, &t->sctp_connection, 1);
+
+  return s;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp4_listen_phase_node) =
+{
+  .name = "sctp4-listen",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_LISTEN_PHASE_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_LISTEN_PHASE_NEXT_##s] = n,
+    foreach_sctp_state_next
+#undef _
+  },
+  .format_trace = format_sctp_rx_trace_short,
+};
+/* *INDENT-ON* */
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp6_listen_phase_node) =
+{
+  .name = "sctp6-listen",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_LISTEN_PHASE_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_LISTEN_PHASE_NEXT_##s] = n,
+    foreach_sctp_state_next
+#undef _
+  },
+  .format_trace = format_sctp_rx_trace_short,
+};
+/* *INDENT-ON* */
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp4_established_phase_node) =
+{
+  .name = "sctp4-established",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_ESTABLISHED_PHASE_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_ESTABLISHED_PHASE_NEXT_##s] = n,
+    foreach_sctp_state_next
+#undef _
+  },
+  .format_trace = format_sctp_rx_trace_short,
+};
+/* *INDENT-ON* */
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp6_established_phase_node) =
+{
+  .name = "sctp6-established",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_LISTEN_PHASE_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_LISTEN_PHASE_NEXT_##s] = n,
+    foreach_sctp_state_next
+#undef _
+  },
+  .format_trace = format_sctp_rx_trace_short,
+};
+/* *INDENT-ON* */
+
+/*
+ * This is the function executed first for the SCTP graph.
+ * It takes care of doing the initial message parsing and
+ * dispatch to the specialized function.
+ */
+always_inline uword
+sctp46_input_dispatcher (vlib_main_t * vm, vlib_node_runtime_t * node,
+			 vlib_frame_t * from_frame, int is_ip4)
+{
+  u32 n_left_from, next_index, *from, *to_next;
+  u32 my_thread_index = vm->thread_index;
+  u8 result;
+  sctp_main_t *tm = vnet_get_sctp_main ();
+
+  from = vlib_frame_vector_args (from_frame);
+  n_left_from = from_frame->n_vectors;
+  next_index = node->cached_next_index;
+  sctp_set_time_now (my_thread_index);
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  int n_advance_bytes0, n_data_bytes0;
+	  u32 bi0, fib_index0;
+	  vlib_buffer_t *b0;
+	  sctp_header_t *sctp_hdr = 0;
+	  sctp_chunks_common_hdr_t *sctp_chunk_hdr = 0;
+	  sctp_connection_t *sctp_conn;
+	  transport_connection_t *trans_conn;
+	  ip4_header_t *ip4_hdr;
+	  ip6_header_t *ip6_hdr;
+	  u32 error0 = SCTP_ERROR_NO_LISTENER, next0 = SCTP_INPUT_NEXT_DROP;
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  sctp_buffer_opaque (b0)->sctp.flags = 0;
+	  fib_index0 = vnet_buffer (b0)->ip.fib_index;
+
+	  /* Checksum computed by ipx_local no need to compute again */
+
+	  if (is_ip4)
+	    {
+	      ip4_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip4_next_header (ip4_hdr);
+
+	      sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
+	      sctp_chunk_hdr = &full_hdr->common_hdr;
+
+	      n_advance_bytes0 =
+		(ip4_header_bytes (ip4_hdr) +
+		 sizeof (sctp_payload_data_chunk_t));
+	      n_data_bytes0 =
+		clib_net_to_host_u16 (ip4_hdr->length) - n_advance_bytes0;
+
+	      trans_conn = session_lookup_connection_wt4 (fib_index0,
+							  &ip4_hdr->dst_address,
+							  &ip4_hdr->src_address,
+							  sctp_hdr->dst_port,
+							  sctp_hdr->src_port,
+							  TRANSPORT_PROTO_SCTP,
+							  my_thread_index,
+							  &result);
+	    }
+	  else
+	    {
+	      ip6_hdr = vlib_buffer_get_current (b0);
+	      sctp_hdr = ip6_next_header (ip6_hdr);
+
+	      sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
+	      sctp_chunk_hdr = &full_hdr->common_hdr;
+
+	      n_advance_bytes0 = sctp_header_bytes ();
+	      n_data_bytes0 =
+		clib_net_to_host_u16 (ip6_hdr->payload_length) -
+		n_advance_bytes0;
+	      n_advance_bytes0 += sizeof (ip6_hdr[0]);
+
+	      trans_conn = session_lookup_connection_wt6 (fib_index0,
+							  &ip6_hdr->dst_address,
+							  &ip6_hdr->src_address,
+							  sctp_hdr->dst_port,
+							  sctp_hdr->src_port,
+							  TRANSPORT_PROTO_SCTP,
+							  my_thread_index,
+							  &result);
+	    }
+
+	  /* Length check */
+	  if (PREDICT_FALSE (n_advance_bytes0 < 0))
+	    {
+	      error0 = SCTP_ERROR_LENGTH;
+	      goto done;
+	    }
+
+	  sctp_conn = sctp_get_connection_from_transport (trans_conn);
+	  vnet_sctp_common_hdr_params_net_to_host (sctp_chunk_hdr);
+
+	  u8 chunk_type = vnet_sctp_get_chunk_type (sctp_chunk_hdr);
+	  if (chunk_type >= UNKNOWN)
+	    {
+	      clib_warning
+		("Received an unrecognized chunk; sending back OPERATION_ERROR chunk");
+
+	      sctp_prepare_operation_error (sctp_conn, SCTP_PRIMARY_PATH_IDX,
+					    b0, UNRECOGNIZED_CHUNK_TYPE);
+
+	      error0 = SCTP_ERROR_UNKNOWN_CHUNK;
+	      next0 = sctp_next_output (is_ip4);
+	      goto done;
+	    }
+
+	  sctp_buffer_opaque (b0)->sctp.hdr_offset =
+	    (u8 *) sctp_hdr - (u8 *) vlib_buffer_get_current (b0);
+
+	  /* Session exists */
+	  if (PREDICT_TRUE (0 != sctp_conn))
+	    {
+	      /* Save connection index */
+	      sctp_buffer_opaque (b0)->sctp.connection_index
+		= trans_conn->c_index;
+	      sctp_buffer_opaque (b0)->sctp.data_offset = n_advance_bytes0;
+	      sctp_buffer_opaque (b0)->sctp.data_len = n_data_bytes0;
+
+	      next0 = tm->dispatch_table[sctp_conn->state][chunk_type].next;
+	      error0 = tm->dispatch_table[sctp_conn->state][chunk_type].error;
+
+	      SCTP_DBG_STATE_MACHINE
+		("S_INDEX = %u, C_INDEX = %u, TRANS_CONN = %p, SCTP_CONN = %p, CURRENT_CONNECTION_STATE = %s,"
+		 "CHUNK_TYPE_RECEIVED = %s " "NEXT_PHASE = %s",
+		 sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].
+		 connection.s_index,
+		 sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].
+		 connection.c_index, trans_conn, sctp_conn,
+		 sctp_state_to_string (sctp_conn->state),
+		 sctp_chunk_to_string (chunk_type), phase_to_string (next0));
+
+	      if (chunk_type == DATA)
+		SCTP_ADV_DBG ("n_advance_bytes0 = %u, n_data_bytes0 = %u",
+			      n_advance_bytes0, n_data_bytes0);
+
+	    }
+	  else
+	    {
+	      if (result)
+		{
+		  next0 = SCTP_INPUT_NEXT_DROP;
+		  error0 = SCTP_ERROR_NONE + result;
+		}
+	      else if ((is_ip4 && tm->punt_unknown4) ||
+		       (!is_ip4 && tm->punt_unknown6))
+		{
+		  next0 = SCTP_INPUT_NEXT_PUNT_PHASE;
+		  error0 = SCTP_ERROR_PUNT;
+		}
+	      else
+		{
+		  next0 = SCTP_INPUT_NEXT_DROP;
+		  error0 = SCTP_ERROR_NO_LISTENER;
+		}
+	      SCTP_DBG_STATE_MACHINE ("sctp_conn == NULL, NEXT_PHASE = %s",
+				      phase_to_string (next0));
+	      sctp_conn = 0;
+	    }
+
+	done:
+	  b0->error = error0 ? node->errors[error0] : 0;
+
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      sctp_rx_trace_t *t0 =
+		vlib_add_trace (vm, node, b0, sizeof (*t0));
+	      sctp_set_rx_trace_data (t0, sctp_conn, sctp_hdr, b0, is_ip4);
+	    }
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+  return from_frame->n_vectors;
+}
+
+VLIB_NODE_FN (sctp4_input_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
+				 vlib_frame_t * from_frame)
+{
+  return sctp46_input_dispatcher (vm, node, from_frame, 1 /* is_ip4 */ );
+}
+
+VLIB_NODE_FN (sctp6_input_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
+				 vlib_frame_t * from_frame)
+{
+  return sctp46_input_dispatcher (vm, node, from_frame, 0 /* is_ip4 */ );
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp4_input_node) =
+{
+  .name = "sctp4-input",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_INPUT_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_INPUT_NEXT_##s] = n,
+    foreach_sctp4_input_next
+#undef _
+  },
+  .format_buffer = format_sctp_header,
+  .format_trace = format_sctp_rx_trace,
+};
+/* *INDENT-ON* */
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp6_input_node) =
+{
+  .name = "sctp6-input",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_INPUT_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [SCTP_INPUT_NEXT_##s] = n,
+    foreach_sctp6_input_next
+#undef _
+  },
+  .format_buffer = format_sctp_header,
+  .format_trace = format_sctp_rx_trace,
+};
+/* *INDENT-ON* */
+
+#ifndef CLIB_MARCH_VARIANT
+static void
+sctp_dispatch_table_init (sctp_main_t * tm)
+{
+  int i, j;
+  for (i = 0; i < ARRAY_LEN (tm->dispatch_table); i++)
+    for (j = 0; j < ARRAY_LEN (tm->dispatch_table[i]); j++)
+      {
+	tm->dispatch_table[i][j].next = SCTP_INPUT_NEXT_DROP;
+	tm->dispatch_table[i][j].error = SCTP_ERROR_DISPATCH;
+      }
+
+#define _(t,f,n,e)                                           	\
+do {                                                       	\
+    tm->dispatch_table[SCTP_STATE_##t][f].next = (n);         	\
+    tm->dispatch_table[SCTP_STATE_##t][f].error = (e);        	\
+} while (0)
+
+  /*
+   * SCTP STATE-MACHINE states:
+   *
+   * _(CLOSED, "CLOSED")                         \
+   * _(COOKIE_WAIT, "COOKIE_WAIT")               \
+   * _(COOKIE_ECHOED, "COOKIE_ECHOED")           \
+   * _(ESTABLISHED, "ESTABLISHED")               \
+   * _(SHUTDOWN_PENDING, "SHUTDOWN_PENDING")     \
+   * _(SHUTDOWN_SENT, "SHUTDOWN_SENT")           \
+   * _(SHUTDOWN_RECEIVED, "SHUTDOWN_RECEIVED")   \
+   * _(SHUTDOWN_ACK_SENT, "SHUTDOWN_ACK_SENT")
+   */
+  //_(CLOSED, DATA, SCTP_INPUT_NEXT_LISTEN_PHASE, SCTP_ERROR_NONE);     /* UNEXPECTED DATA chunk which requires special handling */
+  _(CLOSED, INIT, SCTP_INPUT_NEXT_LISTEN_PHASE, SCTP_ERROR_NONE);
+  _(CLOSED, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED INIT_ACK chunk */
+  _(CLOSED, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);	/* UNEXPECTED SACK chunk */
+  _(CLOSED, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT chunk */
+  _(CLOSED, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT_ACK chunk */
+  _(CLOSED, ABORT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);
+  _(CLOSED, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN chunk */
+  _(CLOSED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN_ACK chunk */
+  _(CLOSED, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);	/* UNEXPECTED OPERATION_ERROR chunk */
+  _(CLOSED, COOKIE_ECHO, SCTP_INPUT_NEXT_ESTABLISHED_PHASE, SCTP_ERROR_NONE);
+  _(CLOSED, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
+  _(CLOSED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
+  _(CLOSED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
+  _(CLOSED, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);	/* UNEXPECTED SHUTDOWN_COMPLETE chunk */
+  _(CLOSED, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE, SCTP_ERROR_NONE);
+
+  _(COOKIE_WAIT, DATA, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_NONE);	/* UNEXPECTED DATA chunk which requires special handling */
+  _(COOKIE_WAIT, INIT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);	/* UNEXPECTED INIT chunk which requires special handling */
+  _(COOKIE_WAIT, INIT_ACK, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);
+  _(COOKIE_WAIT, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);	/* UNEXPECTED SACK chunk */
+  _(COOKIE_WAIT, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT chunk */
+  _(COOKIE_WAIT, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT_ACK chunk */
+  _(COOKIE_WAIT, ABORT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);
+  _(COOKIE_WAIT, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN chunk */
+  _(COOKIE_WAIT, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN_ACK chunk */
+  _(COOKIE_WAIT, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);	/* UNEXPECTED OPERATION_ERROR chunk */
+  _(COOKIE_WAIT, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);	/* UNEXPECTED COOKIE_ECHO chunk */
+  _(COOKIE_WAIT, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
+  _(COOKIE_WAIT, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
+  _(COOKIE_WAIT, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
+  _(COOKIE_WAIT, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);	/* UNEXPECTED SHUTDOWN_COMPLETE chunk */
+  _(COOKIE_WAIT, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+
+  _(COOKIE_ECHOED, DATA, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_NONE);
+  _(COOKIE_ECHOED, INIT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);	/* UNEXPECTED INIT chunk which requires special handling */
+  _(COOKIE_ECHOED, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED INIT_ACK chunk */
+  _(COOKIE_ECHOED, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);	/* UNEXPECTED SACK chunk */
+  _(COOKIE_ECHOED, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT chunk */
+  _(COOKIE_ECHOED, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT_ACK chunk */
+  _(COOKIE_ECHOED, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);	/* UNEXPECTED ABORT chunk */
+  _(COOKIE_ECHOED, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN chunk */
+  _(COOKIE_ECHOED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN_ACK chunk */
+  _(COOKIE_ECHOED, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);	/* UNEXPECTED OPERATION_ERROR chunk */
+  _(COOKIE_ECHOED, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);	/* UNEXPECTED COOKIE_ECHO chunk */
+  _(COOKIE_ECHOED, COOKIE_ACK, SCTP_INPUT_NEXT_ESTABLISHED_PHASE,
+    SCTP_ERROR_NONE);
+  _(COOKIE_ECHOED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
+  _(COOKIE_ECHOED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
+  _(COOKIE_ECHOED, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);	/* UNEXPECTED SHUTDOWN_COMPLETE chunk */
+  _(COOKIE_ECHOED, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+
+  _(ESTABLISHED, DATA, SCTP_INPUT_NEXT_ESTABLISHED_PHASE, SCTP_ERROR_NONE);
+  _(ESTABLISHED, INIT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_INIT_CHUNK_VIOLATION);	/* UNEXPECTED INIT chunk */
+  _(ESTABLISHED, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED INIT_ACK chunk */
+  _(ESTABLISHED, SACK, SCTP_INPUT_NEXT_ESTABLISHED_PHASE, SCTP_ERROR_NONE);
+  _(ESTABLISHED, HEARTBEAT, SCTP_INPUT_NEXT_ESTABLISHED_PHASE,
+    SCTP_ERROR_NONE);
+  _(ESTABLISHED, HEARTBEAT_ACK, SCTP_INPUT_NEXT_ESTABLISHED_PHASE,
+    SCTP_ERROR_NONE);
+  _(ESTABLISHED, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);	/* UNEXPECTED ABORT chunk */
+  _(ESTABLISHED, SHUTDOWN, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
+  _(ESTABLISHED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN_ACK chunk */
+  _(ESTABLISHED, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);	/* UNEXPECTED OPERATION_ERROR chunk */
+  _(ESTABLISHED, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);	/* UNEXPECTED COOKIE_ECHO chunk */
+  _(ESTABLISHED, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
+  _(ESTABLISHED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
+  _(ESTABLISHED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
+  _(ESTABLISHED, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);	/* UNEXPECTED SHUTDOWN_COMPLETE chunk */
+  _(ESTABLISHED, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+
+  _(SHUTDOWN_PENDING, DATA, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
+  _(SHUTDOWN_PENDING, INIT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_INIT_CHUNK_VIOLATION);	/* UNEXPECTED INIT chunk */
+  _(SHUTDOWN_PENDING, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED INIT_ACK chunk */
+  _(SHUTDOWN_PENDING, SACK, SCTP_INPUT_NEXT_LISTEN_PHASE, SCTP_ERROR_NONE);
+  _(SHUTDOWN_PENDING, HEARTBEAT, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_PENDING, HEARTBEAT_ACK, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_PENDING, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);	/* UNEXPECTED ABORT chunk */
+  _(SHUTDOWN_PENDING, SHUTDOWN, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_PENDING, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN_ACK chunk */
+  _(SHUTDOWN_PENDING, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);	/* UNEXPECTED OPERATION_ERROR chunk */
+  _(SHUTDOWN_PENDING, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_PENDING, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
+  _(SHUTDOWN_PENDING, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
+  _(SHUTDOWN_PENDING, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
+  _(SHUTDOWN_PENDING, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);	/* UNEXPECTED SHUTDOWN_COMPLETE chunk */
+  _(SHUTDOWN_PENDING, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+
+  _(SHUTDOWN_SENT, DATA, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
+  _(SHUTDOWN_SENT, INIT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_INIT_CHUNK_VIOLATION);	/* UNEXPECTED INIT chunk */
+  _(SHUTDOWN_SENT, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED INIT_ACK chunk */
+  _(SHUTDOWN_SENT, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);	/* UNEXPECTED SACK chunk */
+  _(SHUTDOWN_SENT, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT chunk */
+  _(SHUTDOWN_SENT, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT_ACK chunk */
+  _(SHUTDOWN_SENT, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);	/* UNEXPECTED ABORT chunk */
+  _(SHUTDOWN_SENT, SHUTDOWN, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
+  _(SHUTDOWN_SENT, SHUTDOWN_ACK, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_SENT, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_SENT, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
+  _(SHUTDOWN_SENT, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
+  _(SHUTDOWN_SENT, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
+  _(SHUTDOWN_SENT, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);	/* UNEXPECTED SHUTDOWN_COMPLETE chunk */
+  _(SHUTDOWN_SENT, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+
+  _(SHUTDOWN_RECEIVED, DATA, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_DATA_CHUNK_VIOLATION);	/* UNEXPECTED DATA chunk */
+  _(SHUTDOWN_RECEIVED, INIT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_INIT_CHUNK_VIOLATION);	/* UNEXPECTED INIT chunk */
+  _(SHUTDOWN_RECEIVED, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED INIT_ACK chunk */
+  _(SHUTDOWN_RECEIVED, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);	/* UNEXPECTED INIT chunk */
+  _(SHUTDOWN_RECEIVED, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT chunk */
+  _(SHUTDOWN_RECEIVED, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT_ACK chunk */
+  _(SHUTDOWN_RECEIVED, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);	/* UNEXPECTED ABORT chunk */
+  _(SHUTDOWN_RECEIVED, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN chunk */
+  _(SHUTDOWN_RECEIVED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_RECEIVED, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_RECEIVED, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
+  _(SHUTDOWN_RECEIVED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
+  _(SHUTDOWN_RECEIVED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
+  _(SHUTDOWN_RECEIVED, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);	/* UNEXPECTED SHUTDOWN_COMPLETE chunk */
+  _(SHUTDOWN_RECEIVED, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+
+  _(SHUTDOWN_ACK_SENT, DATA, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_DATA_CHUNK_VIOLATION);	/* UNEXPECTED DATA chunk */
+  _(SHUTDOWN_ACK_SENT, INIT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);	/* UNEXPECTED INIT chunk */
+  _(SHUTDOWN_ACK_SENT, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED INIT_ACK chunk */
+  _(SHUTDOWN_ACK_SENT, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);	/* UNEXPECTED INIT chunk */
+  _(SHUTDOWN_ACK_SENT, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT chunk */
+  _(SHUTDOWN_ACK_SENT, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);	/* UNEXPECTED HEARTBEAT_ACK chunk */
+  _(SHUTDOWN_ACK_SENT, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);	/* UNEXPECTED ABORT chunk */
+  _(SHUTDOWN_ACK_SENT, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN chunk */
+  _(SHUTDOWN_ACK_SENT, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);	/* UNEXPECTED SHUTDOWN_ACK chunk */
+  _(SHUTDOWN_ACK_SENT, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_ACK_SENT, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);	/* UNEXPECTED COOKIE_ACK chunk */
+  _(SHUTDOWN_ACK_SENT, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);	/* UNEXPECTED ECNE chunk */
+  _(SHUTDOWN_ACK_SENT, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);	/* UNEXPECTED CWR chunk */
+  _(SHUTDOWN_ACK_SENT, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
+    SCTP_ERROR_NONE);
+  _(SHUTDOWN_ACK_SENT, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
+    SCTP_ERROR_NONE);
+
+  /* TODO: Handle COOKIE ECHO when a TCB Exists */
+
+#undef _
+}
+
+clib_error_t *
+sctp_input_init (vlib_main_t * vm)
+{
+  clib_error_t *error = 0;
+  sctp_main_t *tm = vnet_get_sctp_main ();
+
+  if ((error = vlib_call_init_function (vm, sctp_init)))
+    return error;
+
+  /* Initialize dispatch table. */
+  sctp_dispatch_table_init (tm);
+
+  return error;
+}
+
+VLIB_INIT_FUNCTION (sctp_input_init);
+#endif /* CLIB_MARCH_VARIANT */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp_msg_enum.h b/src/plugins/sctp/sctp_msg_enum.h
new file mode 100644
index 00000000000..cbf84c659f6
--- /dev/null
+++ b/src/plugins/sctp/sctp_msg_enum.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_sctp_msg_enum_h
+#define included_sctp_msg_enum_h
+
+#include <vppinfra/byte_order.h>
+
+#define vl_msg_id(n,h) n,
+typedef enum {
+#include <sctp/sctp_all_api_h.h>
+    /* We'll want to know how many messages IDs we need... */
+    VL_MSG_FIRST_AVAILABLE,
+} vl_msg_id_t;
+#undef vl_msg_id
+
+#endif /* included_http_static_msg_enum_h */
diff --git a/src/plugins/sctp/sctp_output.c b/src/plugins/sctp/sctp_output.c
new file mode 100644
index 00000000000..955010a34b3
--- /dev/null
+++ b/src/plugins/sctp/sctp_output.c
@@ -0,0 +1,1568 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <sctp/sctp.h>
+#include <sctp/sctp_debug.h>
+#include <vppinfra/random.h>
+#include <openssl/hmac.h>
+
+/**
+ * Flush tx frame populated by retransmits and timer pops
+ */
+void
+sctp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
+{
+  if (sctp_main.tx_frames[!is_ip4][thread_index])
+    {
+      u32 next_index;
+      next_index = is_ip4 ? sctp4_output_node.index : sctp6_output_node.index;
+      vlib_put_frame_to_node (vm, next_index,
+			      sctp_main.tx_frames[!is_ip4][thread_index]);
+      sctp_main.tx_frames[!is_ip4][thread_index] = 0;
+    }
+}
+
+/**
+ * Flush ip lookup tx frames populated by timer pops
+ */
+always_inline void
+sctp_flush_frame_to_ip_lookup (vlib_main_t * vm, u8 thread_index, u8 is_ip4)
+{
+  if (sctp_main.ip_lookup_tx_frames[!is_ip4][thread_index])
+    {
+      u32 next_index;
+      next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
+      vlib_put_frame_to_node (vm, next_index,
+			      sctp_main.ip_lookup_tx_frames[!is_ip4]
+			      [thread_index]);
+      sctp_main.ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
+    }
+}
+
+/**
+ * Flush v4 and v6 sctp and ip-lookup tx frames for thread index
+ */
+void
+sctp_flush_frames_to_output (u8 thread_index)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  sctp_flush_frame_to_output (vm, thread_index, 1);
+  sctp_flush_frame_to_output (vm, thread_index, 0);
+  sctp_flush_frame_to_ip_lookup (vm, thread_index, 1);
+  sctp_flush_frame_to_ip_lookup (vm, thread_index, 0);
+}
+
+u32
+ip4_sctp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
+			   ip4_header_t * ip0)
+{
+  ip_csum_t checksum;
+  u32 ip_header_length, payload_length_host_byte_order;
+  u32 n_this_buffer, n_bytes_left, n_ip_bytes_this_buffer;
+  void *data_this_buffer;
+
+  /* Initialize checksum with ip header. */
+  ip_header_length = ip4_header_bytes (ip0);
+  payload_length_host_byte_order =
+    clib_net_to_host_u16 (ip0->length) - ip_header_length;
+  checksum =
+    clib_host_to_net_u32 (payload_length_host_byte_order +
+			  (ip0->protocol << 16));
+
+  if (BITS (uword) == 32)
+    {
+      checksum =
+	ip_csum_with_carry (checksum,
+			    clib_mem_unaligned (&ip0->src_address, u32));
+      checksum =
+	ip_csum_with_carry (checksum,
+			    clib_mem_unaligned (&ip0->dst_address, u32));
+    }
+  else
+    checksum =
+      ip_csum_with_carry (checksum,
+			  clib_mem_unaligned (&ip0->src_address, u64));
+
+  n_bytes_left = n_this_buffer = payload_length_host_byte_order;
+  data_this_buffer = (void *) ip0 + ip_header_length;
+  n_ip_bytes_this_buffer =
+    p0->current_length - (((u8 *) ip0 - p0->data) - p0->current_data);
+  if (n_this_buffer + ip_header_length > n_ip_bytes_this_buffer)
+    {
+      n_this_buffer = n_ip_bytes_this_buffer > ip_header_length ?
+	n_ip_bytes_this_buffer - ip_header_length : 0;
+    }
+  while (1)
+    {
+      checksum =
+	ip_incremental_checksum (checksum, data_this_buffer, n_this_buffer);
+      n_bytes_left -= n_this_buffer;
+      if (n_bytes_left == 0)
+	break;
+
+      ASSERT (p0->flags & VLIB_BUFFER_NEXT_PRESENT);
+      p0 = vlib_get_buffer (vm, p0->next_buffer);
+      data_this_buffer = vlib_buffer_get_current (p0);
+      n_this_buffer = p0->current_length;
+    }
+
+  return checksum;
+}
+
+u32
+ip6_sctp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
+			   ip6_header_t * ip0, int *bogus_lengthp)
+{
+  ip_csum_t checksum;
+  u16 payload_length_host_byte_order;
+  u32 i, n_this_buffer, n_bytes_left;
+  u32 headers_size = sizeof (ip0[0]);
+  void *data_this_buffer;
+
+  ASSERT (bogus_lengthp);
+  *bogus_lengthp = 0;
+
+  /* Initialize checksum with ip header. */
+  checksum = ip0->payload_length + clib_host_to_net_u16 (ip0->protocol);
+  payload_length_host_byte_order = clib_net_to_host_u16 (ip0->payload_length);
+  data_this_buffer = (void *) (ip0 + 1);
+
+  for (i = 0; i < ARRAY_LEN (ip0->src_address.as_uword); i++)
+    {
+      checksum = ip_csum_with_carry (checksum,
+				     clib_mem_unaligned (&ip0->
+							 src_address.as_uword
+							 [i], uword));
+      checksum =
+	ip_csum_with_carry (checksum,
+			    clib_mem_unaligned (&ip0->dst_address.as_uword[i],
+						uword));
+    }
+
+  /* some icmp packets may come with a "router alert" hop-by-hop extension header (e.g., mldv2 packets)
+   * or UDP-Ping packets */
+  if (PREDICT_FALSE (ip0->protocol == IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS))
+    {
+      u32 skip_bytes;
+      ip6_hop_by_hop_ext_t *ext_hdr =
+	(ip6_hop_by_hop_ext_t *) data_this_buffer;
+
+      /* validate really icmp6 next */
+      ASSERT ((ext_hdr->next_hdr == IP_PROTOCOL_SCTP));
+
+      skip_bytes = 8 * (1 + ext_hdr->n_data_u64s);
+      data_this_buffer = (void *) ((u8 *) data_this_buffer + skip_bytes);
+
+      payload_length_host_byte_order -= skip_bytes;
+      headers_size += skip_bytes;
+    }
+
+  n_bytes_left = n_this_buffer = payload_length_host_byte_order;
+  if (p0 && n_this_buffer + headers_size > p0->current_length)
+    n_this_buffer =
+      p0->current_length >
+      headers_size ? p0->current_length - headers_size : 0;
+  while (1)
+    {
+      checksum =
+	ip_incremental_checksum (checksum, data_this_buffer, n_this_buffer);
+      n_bytes_left -= n_this_buffer;
+      if (n_bytes_left == 0)
+	break;
+
+      if (!(p0->flags & VLIB_BUFFER_NEXT_PRESENT))
+	{
+	  *bogus_lengthp = 1;
+	  return 0xfefe;
+	}
+      p0 = vlib_get_buffer (vm, p0->next_buffer);
+      data_this_buffer = vlib_buffer_get_current (p0);
+      n_this_buffer = p0->current_length;
+    }
+
+  return checksum;
+}
+
+void
+sctp_push_ip_hdr (sctp_main_t * tm, sctp_sub_connection_t * sctp_sub_conn,
+		  vlib_buffer_t * b)
+{
+  sctp_header_t *th = vlib_buffer_get_current (b);
+  vlib_main_t *vm = vlib_get_main ();
+  if (sctp_sub_conn->c_is_ip4)
+    {
+      ip4_header_t *ih;
+      ih = vlib_buffer_push_ip4 (vm, b, &sctp_sub_conn->c_lcl_ip4,
+				 &sctp_sub_conn->c_rmt_ip4, IP_PROTOCOL_SCTP,
+				 1);
+      th->checksum = ip4_sctp_compute_checksum (vm, b, ih);
+    }
+  else
+    {
+      ip6_header_t *ih;
+      int bogus = ~0;
+
+      ih = vlib_buffer_push_ip6 (vm, b, &sctp_sub_conn->c_lcl_ip6,
+				 &sctp_sub_conn->c_rmt_ip6, IP_PROTOCOL_SCTP);
+      th->checksum = ip6_sctp_compute_checksum (vm, b, ih, &bogus);
+      ASSERT (!bogus);
+    }
+}
+
+always_inline void *
+sctp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b)
+{
+  if (b->flags & VLIB_BUFFER_NEXT_PRESENT)
+    vlib_buffer_free_one (vm, b->next_buffer);
+  /* Zero all flags but free list index and trace flag */
+  b->flags &= VLIB_BUFFER_NEXT_PRESENT - 1;
+  b->current_data = 0;
+  b->current_length = 0;
+  b->total_length_not_including_first_buffer = 0;
+  sctp_buffer_opaque (b)->sctp.flags = 0;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = MAX_SCTP_CONNECTIONS;
+
+  /* Leave enough space for headers */
+  return vlib_buffer_make_headroom (b, TRANSPORT_MAX_HDRS_LEN);
+}
+
+always_inline void *
+sctp_init_buffer (vlib_main_t * vm, vlib_buffer_t * b)
+{
+  ASSERT ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
+  b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
+  b->total_length_not_including_first_buffer = 0;
+  sctp_buffer_opaque (b)->sctp.flags = 0;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = MAX_SCTP_CONNECTIONS;
+  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b);
+  /* Leave enough space for headers */
+  return vlib_buffer_make_headroom (b, TRANSPORT_MAX_HDRS_LEN);
+}
+
+always_inline int
+sctp_alloc_tx_buffers (sctp_main_t * tm, u8 thread_index, u32 n_free_buffers)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  u32 current_length = vec_len (tm->tx_buffers[thread_index]);
+  u32 n_allocated;
+
+  vec_validate (tm->tx_buffers[thread_index],
+		current_length + n_free_buffers - 1);
+  n_allocated =
+    vlib_buffer_alloc (vm, &tm->tx_buffers[thread_index][current_length],
+		       n_free_buffers);
+  _vec_len (tm->tx_buffers[thread_index]) = current_length + n_allocated;
+  /* buffer shortage, report failure */
+  if (vec_len (tm->tx_buffers[thread_index]) == 0)
+    {
+      clib_warning ("out of buffers");
+      return -1;
+    }
+  return 0;
+}
+
+always_inline int
+sctp_get_free_buffer_index (sctp_main_t * tm, u32 * bidx)
+{
+  u32 *my_tx_buffers;
+  u32 thread_index = vlib_get_thread_index ();
+  if (PREDICT_FALSE (vec_len (tm->tx_buffers[thread_index]) == 0))
+    {
+      if (sctp_alloc_tx_buffers (tm, thread_index, VLIB_FRAME_SIZE))
+	return -1;
+    }
+  my_tx_buffers = tm->tx_buffers[thread_index];
+  *bidx = my_tx_buffers[vec_len (my_tx_buffers) - 1];
+  _vec_len (my_tx_buffers) -= 1;
+  return 0;
+}
+
+always_inline void
+sctp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
+			  u8 is_ip4, u8 flush)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  u32 thread_index = vlib_get_thread_index ();
+  u32 *to_next, next_index;
+  vlib_frame_t *f;
+
+  b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
+  b->error = 0;
+
+  /* Decide where to send the packet */
+  next_index = is_ip4 ? sctp4_output_node.index : sctp6_output_node.index;
+  sctp_trajectory_add_start (b, 2);
+
+  /* Get frame to v4/6 output node */
+  f = tm->tx_frames[!is_ip4][thread_index];
+  if (!f)
+    {
+      f = vlib_get_frame_to_node (vm, next_index);
+      ASSERT (f);
+      tm->tx_frames[!is_ip4][thread_index] = f;
+    }
+  to_next = vlib_frame_vector_args (f);
+  to_next[f->n_vectors] = bi;
+  f->n_vectors += 1;
+  if (flush || f->n_vectors == VLIB_FRAME_SIZE)
+    {
+      vlib_put_frame_to_node (vm, next_index, f);
+      tm->tx_frames[!is_ip4][thread_index] = 0;
+    }
+}
+
+always_inline void
+sctp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
+			    u8 is_ip4)
+{
+  sctp_enqueue_to_output_i (vm, b, bi, is_ip4, 1);
+}
+
+always_inline void
+sctp_enqueue_to_ip_lookup_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
+			     u8 is_ip4, u32 fib_index, u8 flush)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  u32 thread_index = vlib_get_thread_index ();
+  u32 *to_next, next_index;
+  vlib_frame_t *f;
+
+  b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
+  b->error = 0;
+
+  vnet_buffer (b)->sw_if_index[VLIB_TX] = fib_index;
+  vnet_buffer (b)->sw_if_index[VLIB_RX] = 0;
+
+  /* Send to IP lookup */
+  next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;
+  if (VLIB_BUFFER_TRACE_TRAJECTORY > 0)
+    {
+      b->pre_data[0] = 2;
+      b->pre_data[1] = next_index;
+    }
+
+  f = tm->ip_lookup_tx_frames[!is_ip4][thread_index];
+  if (!f)
+    {
+      f = vlib_get_frame_to_node (vm, next_index);
+      ASSERT (f);
+      tm->ip_lookup_tx_frames[!is_ip4][thread_index] = f;
+    }
+
+  to_next = vlib_frame_vector_args (f);
+  to_next[f->n_vectors] = bi;
+  f->n_vectors += 1;
+  if (flush || f->n_vectors == VLIB_FRAME_SIZE)
+    {
+      vlib_put_frame_to_node (vm, next_index, f);
+      tm->ip_lookup_tx_frames[!is_ip4][thread_index] = 0;
+    }
+}
+
+always_inline void
+sctp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
+			   u8 is_ip4, u32 fib_index)
+{
+  sctp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, fib_index, 0);
+  if (vm->thread_index == 0 && vlib_num_workers ())
+    session_flush_frames_main_thread (vm);
+}
+
+/**
+ * Convert buffer to INIT
+ */
+void
+sctp_prepare_init_chunk (sctp_connection_t * sctp_conn, u8 idx,
+			 vlib_buffer_t * b)
+{
+  u32 random_seed = random_default_seed ();
+  u16 alloc_bytes = sizeof (sctp_init_chunk_t);
+  sctp_sub_connection_t *sub_conn = &sctp_conn->sub_conn[idx];
+
+  sctp_ipv4_addr_param_t *ip4_param = 0;
+  sctp_ipv6_addr_param_t *ip6_param = 0;
+
+  if (sub_conn->c_is_ip4)
+    alloc_bytes += sizeof (sctp_ipv4_addr_param_t);
+  else
+    alloc_bytes += sizeof (sctp_ipv6_addr_param_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_init_chunk_t *init_chunk = vlib_buffer_push_uninit (b, alloc_bytes);
+
+  u16 pointer_offset = sizeof (init_chunk);
+  if (sub_conn->c_is_ip4)
+    {
+      ip4_param = (sctp_ipv4_addr_param_t *) init_chunk + pointer_offset;
+      ip4_param->address.as_u32 = sub_conn->c_lcl_ip.ip4.as_u32;
+
+      pointer_offset += sizeof (sctp_ipv4_addr_param_t);
+    }
+  else
+    {
+      ip6_param = (sctp_ipv6_addr_param_t *) init_chunk + pointer_offset;
+      ip6_param->address.as_u64[0] = sub_conn->c_lcl_ip.ip6.as_u64[0];
+      ip6_param->address.as_u64[1] = sub_conn->c_lcl_ip.ip6.as_u64[1];
+
+      pointer_offset += sizeof (sctp_ipv6_addr_param_t);
+    }
+
+  init_chunk->sctp_hdr.src_port = sub_conn->c_lcl_port;	/* No need of host_to_net conversion, already in net-byte order */
+  init_chunk->sctp_hdr.dst_port = sub_conn->c_rmt_port;	/* No need of host_to_net conversion, already in net-byte order */
+  init_chunk->sctp_hdr.checksum = 0;
+  /* The sender of an INIT must set the VERIFICATION_TAG to 0 as per RFC 4960 Section 8.5.1 */
+  init_chunk->sctp_hdr.verification_tag = 0x0;
+
+  vnet_sctp_set_chunk_type (&init_chunk->chunk_hdr, INIT);
+  vnet_sctp_set_chunk_length (&init_chunk->chunk_hdr, chunk_len);
+  vnet_sctp_common_hdr_params_host_to_net (&init_chunk->chunk_hdr);
+
+  sctp_init_cwnd (sctp_conn);
+
+  init_chunk->a_rwnd = clib_host_to_net_u32 (sctp_conn->sub_conn[idx].cwnd);
+  init_chunk->initiate_tag = clib_host_to_net_u32 (random_u32 (&random_seed));
+  init_chunk->inboud_streams_count =
+    clib_host_to_net_u16 (INBOUND_STREAMS_COUNT);
+  init_chunk->outbound_streams_count =
+    clib_host_to_net_u16 (OUTBOUND_STREAMS_COUNT);
+
+  init_chunk->initial_tsn =
+    clib_host_to_net_u32 (sctp_conn->local_initial_tsn);
+  SCTP_CONN_TRACKING_DBG ("sctp_conn->local_initial_tsn = %u",
+			  sctp_conn->local_initial_tsn);
+
+  sctp_conn->local_tag = init_chunk->initiate_tag;
+
+  sctp_buffer_opaque (b)->sctp.connection_index = sub_conn->c_c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+
+  SCTP_DBG_STATE_MACHINE ("CONN_INDEX = %u, CURR_CONN_STATE = %u (%s), "
+			  "CHUNK_TYPE = %s, "
+			  "SRC_PORT = %u, DST_PORT = %u",
+			  sub_conn->connection.c_index,
+			  sctp_conn->state,
+			  sctp_state_to_string (sctp_conn->state),
+			  sctp_chunk_to_string (INIT),
+			  init_chunk->sctp_hdr.src_port,
+			  init_chunk->sctp_hdr.dst_port);
+}
+
+void
+sctp_compute_mac (sctp_connection_t * sctp_conn,
+		  sctp_state_cookie_param_t * state_cookie)
+{
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+  HMAC_CTX *ctx;
+#else
+  HMAC_CTX ctx;
+#endif
+  unsigned int len = 0;
+  const EVP_MD *md = EVP_sha1 ();
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+  ctx = HMAC_CTX_new ();
+  HMAC_Init_ex (ctx, &state_cookie->creation_time,
+		sizeof (state_cookie->creation_time), md, NULL);
+  HMAC_Update (ctx, (const unsigned char *) &sctp_conn, sizeof (sctp_conn));
+  HMAC_Final (ctx, state_cookie->mac, &len);
+#else
+  HMAC_CTX_init (&ctx);
+  HMAC_Init_ex (&ctx, &state_cookie->creation_time,
+		sizeof (state_cookie->creation_time), md, NULL);
+  HMAC_Update (&ctx, (const unsigned char *) &sctp_conn, sizeof (sctp_conn));
+  HMAC_Final (&ctx, state_cookie->mac, &len);
+  HMAC_CTX_cleanup (&ctx);
+#endif
+
+  ENDIANESS_SWAP (state_cookie->mac);
+}
+
+void
+sctp_prepare_cookie_ack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+			       vlib_buffer_t * b)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  sctp_reuse_buffer (vm, b);
+
+  u16 alloc_bytes = sizeof (sctp_cookie_ack_chunk_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_cookie_ack_chunk_t *cookie_ack_chunk =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+
+  cookie_ack_chunk->sctp_hdr.checksum = 0;
+  cookie_ack_chunk->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  cookie_ack_chunk->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  cookie_ack_chunk->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+  vnet_sctp_set_chunk_type (&cookie_ack_chunk->chunk_hdr, COOKIE_ACK);
+  vnet_sctp_set_chunk_length (&cookie_ack_chunk->chunk_hdr, chunk_len);
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+void
+sctp_prepare_cookie_echo_chunk (sctp_connection_t * sctp_conn, u8 idx,
+				vlib_buffer_t * b, u8 reuse_buffer)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  if (reuse_buffer)
+    sctp_reuse_buffer (vm, b);
+
+  /* The minimum size of the message is given by the sctp_init_ack_chunk_t */
+  u16 alloc_bytes = sizeof (sctp_cookie_echo_chunk_t);
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+  sctp_cookie_echo_chunk_t *cookie_echo_chunk =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+  cookie_echo_chunk->sctp_hdr.checksum = 0;
+  cookie_echo_chunk->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  cookie_echo_chunk->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  cookie_echo_chunk->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+  vnet_sctp_set_chunk_type (&cookie_echo_chunk->chunk_hdr, COOKIE_ECHO);
+  vnet_sctp_set_chunk_length (&cookie_echo_chunk->chunk_hdr, chunk_len);
+  clib_memcpy_fast (&(cookie_echo_chunk->cookie), &sctp_conn->cookie_param,
+		    sizeof (sctp_state_cookie_param_t));
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+
+/*
+ *  Send COOKIE_ECHO
+ */
+void
+sctp_send_cookie_echo (sctp_connection_t * sctp_conn)
+{
+  vlib_buffer_t *b;
+  u32 bi;
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  vlib_main_t *vm = vlib_get_main ();
+
+  if (PREDICT_FALSE (sctp_conn->init_retransmit_err > SCTP_MAX_INIT_RETRANS))
+    {
+      clib_warning ("Reached MAX_INIT_RETRANS times. Aborting connection.");
+
+      session_stream_connect_notify (&sctp_conn->sub_conn
+				     [SCTP_PRIMARY_PATH_IDX].connection, 1);
+
+      sctp_connection_timers_reset (sctp_conn);
+
+      sctp_connection_cleanup (sctp_conn);
+    }
+
+  if (PREDICT_FALSE (sctp_get_free_buffer_index (tm, &bi)))
+    return;
+
+  b = vlib_get_buffer (vm, bi);
+  u8 idx = SCTP_PRIMARY_PATH_IDX;
+
+  sctp_init_buffer (vm, b);
+  sctp_prepare_cookie_echo_chunk (sctp_conn, idx, b, 0);
+  sctp_enqueue_to_output_now (vm, b, bi, sctp_conn->sub_conn[idx].c_is_ip4);
+
+  /* Start the T1_INIT timer */
+  sctp_timer_set (sctp_conn, idx, SCTP_TIMER_T1_INIT,
+		  sctp_conn->sub_conn[idx].RTO);
+
+  /* Change state to COOKIE_WAIT */
+  sctp_conn->state = SCTP_STATE_COOKIE_WAIT;
+
+  /* Measure RTT with this */
+  sctp_conn->sub_conn[idx].rtt_ts = sctp_time_now ();
+}
+
+
+/**
+ * Convert buffer to ERROR
+ */
+void
+sctp_prepare_operation_error (sctp_connection_t * sctp_conn, u8 idx,
+			      vlib_buffer_t * b, u8 err_cause)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  sctp_reuse_buffer (vm, b);
+
+  /* The minimum size of the message is given by the sctp_operation_error_t */
+  u16 alloc_bytes =
+    sizeof (sctp_operation_error_t) + sizeof (sctp_err_cause_param_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_operation_error_t *err_chunk =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+
+  /* src_port & dst_port are already in network byte-order */
+  err_chunk->sctp_hdr.checksum = 0;
+  err_chunk->sctp_hdr.src_port = sctp_conn->sub_conn[idx].connection.lcl_port;
+  err_chunk->sctp_hdr.dst_port = sctp_conn->sub_conn[idx].connection.rmt_port;
+  /* As per RFC4960 Section 5.2.2: copy the INITIATE_TAG into the VERIFICATION_TAG of the ABORT chunk */
+  err_chunk->sctp_hdr.verification_tag = sctp_conn->local_tag;
+
+  err_chunk->err_causes[0].param_hdr.length =
+    clib_host_to_net_u16 (sizeof (err_chunk->err_causes[0].param_hdr.type) +
+			  sizeof (err_chunk->err_causes[0].param_hdr.length));
+  err_chunk->err_causes[0].param_hdr.type = clib_host_to_net_u16 (err_cause);
+
+  vnet_sctp_set_chunk_type (&err_chunk->chunk_hdr, OPERATION_ERROR);
+  vnet_sctp_set_chunk_length (&err_chunk->chunk_hdr, chunk_len);
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+/**
+ * Convert buffer to ABORT
+ */
+void
+sctp_prepare_abort_for_collision (sctp_connection_t * sctp_conn, u8 idx,
+				  vlib_buffer_t * b, ip4_address_t * ip4_addr,
+				  ip6_address_t * ip6_addr)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  sctp_reuse_buffer (vm, b);
+
+  /* The minimum size of the message is given by the sctp_abort_chunk_t */
+  u16 alloc_bytes = sizeof (sctp_abort_chunk_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_abort_chunk_t *abort_chunk = vlib_buffer_push_uninit (b, alloc_bytes);
+
+  /* src_port & dst_port are already in network byte-order */
+  abort_chunk->sctp_hdr.checksum = 0;
+  abort_chunk->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  abort_chunk->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  /* As per RFC4960 Section 5.2.2: copy the INITIATE_TAG into the VERIFICATION_TAG of the ABORT chunk */
+  abort_chunk->sctp_hdr.verification_tag = sctp_conn->local_tag;
+
+  vnet_sctp_set_chunk_type (&abort_chunk->chunk_hdr, ABORT);
+  vnet_sctp_set_chunk_length (&abort_chunk->chunk_hdr, chunk_len);
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+/**
+ * Convert buffer to INIT-ACK
+ */
+void
+sctp_prepare_initack_chunk_for_collision (sctp_connection_t * sctp_conn,
+					  u8 idx, vlib_buffer_t * b,
+					  ip4_address_t * ip4_addr,
+					  ip6_address_t * ip6_addr)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  sctp_ipv4_addr_param_t *ip4_param = 0;
+  sctp_ipv6_addr_param_t *ip6_param = 0;
+
+  sctp_reuse_buffer (vm, b);
+
+  /* The minimum size of the message is given by the sctp_init_ack_chunk_t */
+  u16 alloc_bytes =
+    sizeof (sctp_init_ack_chunk_t) + sizeof (sctp_state_cookie_param_t);
+
+  if (PREDICT_TRUE (ip4_addr != NULL))
+    {
+      /* Create room for variable-length fields in the INIT_ACK chunk */
+      alloc_bytes += SCTP_IPV4_ADDRESS_TYPE_LENGTH;
+    }
+  if (PREDICT_TRUE (ip6_addr != NULL))
+    {
+      /* Create room for variable-length fields in the INIT_ACK chunk */
+      alloc_bytes += SCTP_IPV6_ADDRESS_TYPE_LENGTH;
+    }
+
+  if (sctp_conn->sub_conn[idx].connection.is_ip4)
+    alloc_bytes += sizeof (sctp_ipv4_addr_param_t);
+  else
+    alloc_bytes += sizeof (sctp_ipv6_addr_param_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_init_ack_chunk_t *init_ack_chunk =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+
+  u16 pointer_offset = sizeof (sctp_init_ack_chunk_t);
+
+  /* Create State Cookie parameter */
+  sctp_state_cookie_param_t *state_cookie_param =
+    (sctp_state_cookie_param_t *) ((char *) init_ack_chunk + pointer_offset);
+
+  state_cookie_param->param_hdr.type =
+    clib_host_to_net_u16 (SCTP_STATE_COOKIE_TYPE);
+  state_cookie_param->param_hdr.length =
+    clib_host_to_net_u16 (sizeof (sctp_state_cookie_param_t));
+  state_cookie_param->creation_time = clib_host_to_net_u64 (sctp_time_now ());
+  state_cookie_param->cookie_lifespan =
+    clib_host_to_net_u32 (SCTP_VALID_COOKIE_LIFE);
+
+  sctp_compute_mac (sctp_conn, state_cookie_param);
+
+  pointer_offset += sizeof (sctp_state_cookie_param_t);
+
+  if (PREDICT_TRUE (ip4_addr != NULL))
+    {
+      sctp_ipv4_addr_param_t *ipv4_addr =
+	(sctp_ipv4_addr_param_t *) init_ack_chunk + pointer_offset;
+
+      ipv4_addr->param_hdr.type =
+	clib_host_to_net_u16 (SCTP_IPV4_ADDRESS_TYPE);
+      ipv4_addr->param_hdr.length =
+	clib_host_to_net_u16 (SCTP_IPV4_ADDRESS_TYPE_LENGTH);
+      ipv4_addr->address.as_u32 = ip4_addr->as_u32;
+
+      pointer_offset += SCTP_IPV4_ADDRESS_TYPE_LENGTH;
+    }
+  if (PREDICT_TRUE (ip6_addr != NULL))
+    {
+      sctp_ipv6_addr_param_t *ipv6_addr =
+	(sctp_ipv6_addr_param_t *) init_ack_chunk + pointer_offset;
+
+      ipv6_addr->param_hdr.type =
+	clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE);
+      ipv6_addr->param_hdr.length =
+	clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE_LENGTH);
+      ipv6_addr->address.as_u64[0] = ip6_addr->as_u64[0];
+      ipv6_addr->address.as_u64[1] = ip6_addr->as_u64[1];
+
+      pointer_offset += SCTP_IPV6_ADDRESS_TYPE_LENGTH;
+    }
+
+  if (sctp_conn->sub_conn[idx].connection.is_ip4)
+    {
+      ip4_param = (sctp_ipv4_addr_param_t *) init_ack_chunk + pointer_offset;
+      ip4_param->address.as_u32 =
+	sctp_conn->sub_conn[idx].connection.lcl_ip.ip4.as_u32;
+
+      pointer_offset += sizeof (sctp_ipv4_addr_param_t);
+    }
+  else
+    {
+      ip6_param = (sctp_ipv6_addr_param_t *) init_ack_chunk + pointer_offset;
+      ip6_param->address.as_u64[0] =
+	sctp_conn->sub_conn[idx].connection.lcl_ip.ip6.as_u64[0];
+      ip6_param->address.as_u64[1] =
+	sctp_conn->sub_conn[idx].connection.lcl_ip.ip6.as_u64[1];
+
+      pointer_offset += sizeof (sctp_ipv6_addr_param_t);
+    }
+
+  /* src_port & dst_port are already in network byte-order */
+  init_ack_chunk->sctp_hdr.checksum = 0;
+  init_ack_chunk->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  init_ack_chunk->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  /* the sctp_conn->verification_tag is already in network byte-order (being a copy of the init_tag coming with the INIT chunk) */
+  init_ack_chunk->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+  init_ack_chunk->initial_tsn =
+    clib_host_to_net_u32 (sctp_conn->local_initial_tsn);
+  SCTP_CONN_TRACKING_DBG ("init_ack_chunk->initial_tsn = %u",
+			  init_ack_chunk->initial_tsn);
+
+  vnet_sctp_set_chunk_type (&init_ack_chunk->chunk_hdr, INIT_ACK);
+  vnet_sctp_set_chunk_length (&init_ack_chunk->chunk_hdr, chunk_len);
+
+  init_ack_chunk->initiate_tag = sctp_conn->local_tag;
+
+  init_ack_chunk->a_rwnd =
+    clib_host_to_net_u32 (sctp_conn->sub_conn[idx].cwnd);
+  init_ack_chunk->inboud_streams_count =
+    clib_host_to_net_u16 (INBOUND_STREAMS_COUNT);
+  init_ack_chunk->outbound_streams_count =
+    clib_host_to_net_u16 (OUTBOUND_STREAMS_COUNT);
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+/**
+ * Convert buffer to INIT-ACK
+ */
+void
+sctp_prepare_initack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+			    vlib_buffer_t * b, ip4_address_t * ip4_addr,
+			    u8 add_ip4, ip6_address_t * ip6_addr, u8 add_ip6)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  sctp_ipv4_addr_param_t *ip4_param = 0;
+  sctp_ipv6_addr_param_t *ip6_param = 0;
+  u32 random_seed = random_default_seed ();
+
+  sctp_reuse_buffer (vm, b);
+
+  /* The minimum size of the message is given by the sctp_init_ack_chunk_t */
+  u16 alloc_bytes =
+    sizeof (sctp_init_ack_chunk_t) + sizeof (sctp_state_cookie_param_t);
+
+  if (PREDICT_FALSE (add_ip4 == 1))
+    {
+      /* Create room for variable-length fields in the INIT_ACK chunk */
+      alloc_bytes += SCTP_IPV4_ADDRESS_TYPE_LENGTH;
+    }
+  if (PREDICT_FALSE (add_ip6 == 1))
+    {
+      /* Create room for variable-length fields in the INIT_ACK chunk */
+      alloc_bytes += SCTP_IPV6_ADDRESS_TYPE_LENGTH;
+    }
+
+  if (sctp_conn->sub_conn[idx].connection.is_ip4)
+    alloc_bytes += sizeof (sctp_ipv4_addr_param_t);
+  else
+    alloc_bytes += sizeof (sctp_ipv6_addr_param_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_init_ack_chunk_t *init_ack_chunk =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+
+  u16 pointer_offset = sizeof (sctp_init_ack_chunk_t);
+
+  /* Create State Cookie parameter */
+  sctp_state_cookie_param_t *state_cookie_param =
+    (sctp_state_cookie_param_t *) ((char *) init_ack_chunk + pointer_offset);
+
+  state_cookie_param->param_hdr.type =
+    clib_host_to_net_u16 (SCTP_STATE_COOKIE_TYPE);
+  state_cookie_param->param_hdr.length =
+    clib_host_to_net_u16 (sizeof (sctp_state_cookie_param_t));
+  state_cookie_param->creation_time = clib_host_to_net_u64 (sctp_time_now ());
+  state_cookie_param->cookie_lifespan =
+    clib_host_to_net_u32 (SCTP_VALID_COOKIE_LIFE);
+
+  sctp_compute_mac (sctp_conn, state_cookie_param);
+
+  pointer_offset += sizeof (sctp_state_cookie_param_t);
+
+  if (PREDICT_TRUE (ip4_addr != NULL))
+    {
+      sctp_ipv4_addr_param_t *ipv4_addr =
+	(sctp_ipv4_addr_param_t *) init_ack_chunk + pointer_offset;
+
+      ipv4_addr->param_hdr.type =
+	clib_host_to_net_u16 (SCTP_IPV4_ADDRESS_TYPE);
+      ipv4_addr->param_hdr.length =
+	clib_host_to_net_u16 (SCTP_IPV4_ADDRESS_TYPE_LENGTH);
+      ipv4_addr->address.as_u32 = ip4_addr->as_u32;
+
+      pointer_offset += SCTP_IPV4_ADDRESS_TYPE_LENGTH;
+    }
+  if (PREDICT_TRUE (ip6_addr != NULL))
+    {
+      sctp_ipv6_addr_param_t *ipv6_addr =
+	(sctp_ipv6_addr_param_t *) init_ack_chunk + pointer_offset;
+
+      ipv6_addr->param_hdr.type =
+	clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE);
+      ipv6_addr->param_hdr.length =
+	clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE_LENGTH);
+      ipv6_addr->address.as_u64[0] = ip6_addr->as_u64[0];
+      ipv6_addr->address.as_u64[1] = ip6_addr->as_u64[1];
+
+      pointer_offset += SCTP_IPV6_ADDRESS_TYPE_LENGTH;
+    }
+
+  if (sctp_conn->sub_conn[idx].connection.is_ip4)
+    {
+      ip4_param = (sctp_ipv4_addr_param_t *) init_ack_chunk + pointer_offset;
+      ip4_param->address.as_u32 =
+	sctp_conn->sub_conn[idx].connection.lcl_ip.ip4.as_u32;
+
+      pointer_offset += sizeof (sctp_ipv4_addr_param_t);
+    }
+  else
+    {
+      ip6_param = (sctp_ipv6_addr_param_t *) init_ack_chunk + pointer_offset;
+      ip6_param->address.as_u64[0] =
+	sctp_conn->sub_conn[idx].connection.lcl_ip.ip6.as_u64[0];
+      ip6_param->address.as_u64[1] =
+	sctp_conn->sub_conn[idx].connection.lcl_ip.ip6.as_u64[1];
+
+      pointer_offset += sizeof (sctp_ipv6_addr_param_t);
+    }
+
+  /* src_port & dst_port are already in network byte-order */
+  init_ack_chunk->sctp_hdr.checksum = 0;
+  init_ack_chunk->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  init_ack_chunk->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  /* the sctp_conn->verification_tag is already in network byte-order (being a copy of the init_tag coming with the INIT chunk) */
+  init_ack_chunk->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+  init_ack_chunk->initial_tsn =
+    clib_host_to_net_u32 (sctp_conn->local_initial_tsn);
+  SCTP_CONN_TRACKING_DBG ("init_ack_chunk->initial_tsn = %u",
+			  init_ack_chunk->initial_tsn);
+
+  vnet_sctp_set_chunk_type (&init_ack_chunk->chunk_hdr, INIT_ACK);
+  vnet_sctp_set_chunk_length (&init_ack_chunk->chunk_hdr, chunk_len);
+
+  init_ack_chunk->initiate_tag =
+    clib_host_to_net_u32 (random_u32 (&random_seed));
+
+  init_ack_chunk->a_rwnd =
+    clib_host_to_net_u32 (sctp_conn->sub_conn[idx].cwnd);
+  init_ack_chunk->inboud_streams_count =
+    clib_host_to_net_u16 (INBOUND_STREAMS_COUNT);
+  init_ack_chunk->outbound_streams_count =
+    clib_host_to_net_u16 (OUTBOUND_STREAMS_COUNT);
+
+  sctp_conn->local_tag = init_ack_chunk->initiate_tag;
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+/**
+ * Convert buffer to SHUTDOWN
+ */
+void
+sctp_prepare_shutdown_chunk (sctp_connection_t * sctp_conn, u8 idx,
+			     vlib_buffer_t * b)
+{
+  u16 alloc_bytes = sizeof (sctp_shutdown_association_chunk_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_shutdown_association_chunk_t *shutdown_chunk =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+
+  shutdown_chunk->sctp_hdr.checksum = 0;
+  /* No need of host_to_net conversion, already in net-byte order */
+  shutdown_chunk->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  shutdown_chunk->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  shutdown_chunk->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+  vnet_sctp_set_chunk_type (&shutdown_chunk->chunk_hdr, SHUTDOWN);
+  vnet_sctp_set_chunk_length (&shutdown_chunk->chunk_hdr, chunk_len);
+
+  shutdown_chunk->cumulative_tsn_ack = sctp_conn->last_rcvd_tsn;
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+/*
+ * Send SHUTDOWN
+ */
+void
+sctp_send_shutdown (sctp_connection_t * sctp_conn)
+{
+  vlib_buffer_t *b;
+  u32 bi;
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  vlib_main_t *vm = vlib_get_main ();
+
+  if (sctp_check_outstanding_data_chunks (sctp_conn) > 0)
+    return;
+
+  if (PREDICT_FALSE (sctp_get_free_buffer_index (tm, &bi)))
+    return;
+
+  u8 idx = SCTP_PRIMARY_PATH_IDX;
+
+  b = vlib_get_buffer (vm, bi);
+  sctp_init_buffer (vm, b);
+  sctp_prepare_shutdown_chunk (sctp_conn, idx, b);
+
+  sctp_enqueue_to_output_now (vm, b, bi,
+			      sctp_conn->sub_conn[idx].connection.is_ip4);
+}
+
+/**
+ * Convert buffer to SHUTDOWN_ACK
+ */
+void
+sctp_prepare_shutdown_ack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+				 vlib_buffer_t * b)
+{
+  u16 alloc_bytes = sizeof (sctp_shutdown_association_chunk_t);
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  sctp_shutdown_ack_chunk_t *shutdown_ack_chunk =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+
+  shutdown_ack_chunk->sctp_hdr.checksum = 0;
+  /* No need of host_to_net conversion, already in net-byte order */
+  shutdown_ack_chunk->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  shutdown_ack_chunk->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  shutdown_ack_chunk->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+
+  vnet_sctp_set_chunk_type (&shutdown_ack_chunk->chunk_hdr, SHUTDOWN_ACK);
+  vnet_sctp_set_chunk_length (&shutdown_ack_chunk->chunk_hdr, chunk_len);
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+/*
+ * Send SHUTDOWN_ACK
+ */
+void
+sctp_send_shutdown_ack (sctp_connection_t * sctp_conn, u8 idx,
+			vlib_buffer_t * b)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  if (sctp_check_outstanding_data_chunks (sctp_conn) > 0)
+    return;
+
+  sctp_reuse_buffer (vm, b);
+
+  sctp_prepare_shutdown_ack_chunk (sctp_conn, idx, b);
+}
+
+/**
+ * Convert buffer to SACK
+ */
+void
+sctp_prepare_sack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+			 vlib_buffer_t * b)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  sctp_reuse_buffer (vm, b);
+
+  u16 alloc_bytes = sizeof (sctp_selective_ack_chunk_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_selective_ack_chunk_t *sack = vlib_buffer_push_uninit (b, alloc_bytes);
+
+  sack->sctp_hdr.checksum = 0;
+  sack->sctp_hdr.src_port = sctp_conn->sub_conn[idx].connection.lcl_port;
+  sack->sctp_hdr.dst_port = sctp_conn->sub_conn[idx].connection.rmt_port;
+  sack->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+  vnet_sctp_set_chunk_type (&sack->chunk_hdr, SACK);
+  vnet_sctp_set_chunk_length (&sack->chunk_hdr, chunk_len);
+
+  sack->cumulative_tsn_ack = sctp_conn->next_tsn_expected;
+
+  sctp_conn->ack_state = 0;
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+/**
+ * Convert buffer to HEARTBEAT_ACK
+ */
+void
+sctp_prepare_heartbeat_ack_chunk (sctp_connection_t * sctp_conn, u8 idx,
+				  vlib_buffer_t * b)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  u16 alloc_bytes = sizeof (sctp_hb_ack_chunk_t);
+
+  sctp_reuse_buffer (vm, b);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_hb_ack_chunk_t *hb_ack = vlib_buffer_push_uninit (b, alloc_bytes);
+
+  hb_ack->sctp_hdr.checksum = 0;
+  /* No need of host_to_net conversion, already in net-byte order */
+  hb_ack->sctp_hdr.src_port = sctp_conn->sub_conn[idx].connection.lcl_port;
+  hb_ack->sctp_hdr.dst_port = sctp_conn->sub_conn[idx].connection.rmt_port;
+  hb_ack->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+  hb_ack->hb_info.param_hdr.type = clib_host_to_net_u16 (1);
+  hb_ack->hb_info.param_hdr.length =
+    clib_host_to_net_u16 (sizeof (hb_ack->hb_info.hb_info));
+
+  vnet_sctp_set_chunk_type (&hb_ack->chunk_hdr, HEARTBEAT_ACK);
+  vnet_sctp_set_chunk_length (&hb_ack->chunk_hdr, chunk_len);
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+/**
+ * Convert buffer to HEARTBEAT
+ */
+void
+sctp_prepare_heartbeat_chunk (sctp_connection_t * sctp_conn, u8 idx,
+			      vlib_buffer_t * b)
+{
+  u16 alloc_bytes = sizeof (sctp_hb_req_chunk_t);
+
+  /* As per RFC 4960 the chunk_length value does NOT contemplate
+   * the size of the first header (see sctp_header_t) and any padding
+   */
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  sctp_hb_req_chunk_t *hb_req = vlib_buffer_push_uninit (b, alloc_bytes);
+
+  hb_req->sctp_hdr.checksum = 0;
+  /* No need of host_to_net conversion, already in net-byte order */
+  hb_req->sctp_hdr.src_port = sctp_conn->sub_conn[idx].connection.lcl_port;
+  hb_req->sctp_hdr.dst_port = sctp_conn->sub_conn[idx].connection.rmt_port;
+  hb_req->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+  hb_req->hb_info.param_hdr.type = clib_host_to_net_u16 (1);
+  hb_req->hb_info.param_hdr.length =
+    clib_host_to_net_u16 (sizeof (hb_req->hb_info.hb_info));
+
+  vnet_sctp_set_chunk_type (&hb_req->chunk_hdr, HEARTBEAT);
+  vnet_sctp_set_chunk_length (&hb_req->chunk_hdr, chunk_len);
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+void
+sctp_send_heartbeat (sctp_connection_t * sctp_conn)
+{
+  vlib_buffer_t *b;
+  u32 bi;
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  vlib_main_t *vm = vlib_get_main ();
+
+  u8 i;
+  u64 now = sctp_time_now ();
+
+  for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
+    {
+      if (sctp_conn->sub_conn[i].state == SCTP_SUBCONN_STATE_DOWN)
+	continue;
+
+      if (now > (sctp_conn->sub_conn[i].last_seen + SCTP_HB_INTERVAL))
+	{
+	  if (PREDICT_FALSE (sctp_get_free_buffer_index (tm, &bi)))
+	    return;
+
+	  b = vlib_get_buffer (vm, bi);
+	  sctp_init_buffer (vm, b);
+	  sctp_prepare_heartbeat_chunk (sctp_conn, i, b);
+
+	  sctp_enqueue_to_output_now (vm, b, bi,
+				      sctp_conn->sub_conn[i].
+				      connection.is_ip4);
+
+	  sctp_conn->sub_conn[i].unacknowledged_hb += 1;
+	}
+    }
+}
+
+/**
+ * Convert buffer to SHUTDOWN_COMPLETE
+ */
+void
+sctp_prepare_shutdown_complete_chunk (sctp_connection_t * sctp_conn, u8 idx,
+				      vlib_buffer_t * b)
+{
+  u16 alloc_bytes = sizeof (sctp_shutdown_association_chunk_t);
+  alloc_bytes += vnet_sctp_calculate_padding (alloc_bytes);
+
+  u16 chunk_len = alloc_bytes - sizeof (sctp_header_t);
+
+  sctp_shutdown_complete_chunk_t *shutdown_complete =
+    vlib_buffer_push_uninit (b, alloc_bytes);
+
+  shutdown_complete->sctp_hdr.checksum = 0;
+  /* No need of host_to_net conversion, already in net-byte order */
+  shutdown_complete->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  shutdown_complete->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  shutdown_complete->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+
+  vnet_sctp_set_chunk_type (&shutdown_complete->chunk_hdr, SHUTDOWN_COMPLETE);
+  vnet_sctp_set_chunk_length (&shutdown_complete->chunk_hdr, chunk_len);
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+void
+sctp_send_shutdown_complete (sctp_connection_t * sctp_conn, u8 idx,
+			     vlib_buffer_t * b0)
+{
+  vlib_main_t *vm = vlib_get_main ();
+
+  if (sctp_check_outstanding_data_chunks (sctp_conn) > 0)
+    return;
+
+  sctp_reuse_buffer (vm, b0);
+
+  sctp_prepare_shutdown_complete_chunk (sctp_conn, idx, b0);
+}
+
+/*
+ *  Send INIT
+ */
+void
+sctp_send_init (sctp_connection_t * sctp_conn)
+{
+  vlib_buffer_t *b;
+  u32 bi;
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  vlib_main_t *vm = vlib_get_main ();
+
+  if (PREDICT_FALSE (sctp_conn->init_retransmit_err > SCTP_MAX_INIT_RETRANS))
+    {
+      clib_warning ("Reached MAX_INIT_RETRANS times. Aborting connection.");
+
+      session_stream_connect_notify (&sctp_conn->sub_conn
+				     [SCTP_PRIMARY_PATH_IDX].connection, 1);
+
+      sctp_connection_timers_reset (sctp_conn);
+
+      sctp_connection_cleanup (sctp_conn);
+
+      return;
+    }
+
+  if (PREDICT_FALSE (sctp_get_free_buffer_index (tm, &bi)))
+    return;
+
+  b = vlib_get_buffer (vm, bi);
+  u8 idx = SCTP_PRIMARY_PATH_IDX;
+
+  sctp_init_buffer (vm, b);
+  sctp_prepare_init_chunk (sctp_conn, idx, b);
+
+  sctp_push_ip_hdr (tm, &sctp_conn->sub_conn[idx], b);
+  sctp_enqueue_to_ip_lookup (vm, b, bi, sctp_conn->sub_conn[idx].c_is_ip4,
+			     sctp_conn->sub_conn[idx].c_fib_index);
+
+  /* Start the T1_INIT timer */
+  sctp_timer_set (sctp_conn, idx, SCTP_TIMER_T1_INIT,
+		  sctp_conn->sub_conn[idx].RTO);
+
+  /* Change state to COOKIE_WAIT */
+  sctp_conn->state = SCTP_STATE_COOKIE_WAIT;
+
+  /* Measure RTT with this */
+  sctp_conn->sub_conn[idx].rtt_ts = sctp_time_now ();
+}
+
+/**
+ * Push SCTP header and update connection variables
+ */
+static void
+sctp_push_hdr_i (sctp_connection_t * sctp_conn, vlib_buffer_t * b,
+		 sctp_state_t next_state)
+{
+  u16 data_len = b->current_length;
+
+  if (b->flags & VLIB_BUFFER_TOTAL_LENGTH_VALID)
+    data_len += b->total_length_not_including_first_buffer;
+
+  ASSERT (!b->total_length_not_including_first_buffer
+	  || (b->flags & VLIB_BUFFER_NEXT_PRESENT)
+	  || !(b->flags & VLIB_BUFFER_TOTAL_LENGTH_VALID));
+
+  SCTP_ADV_DBG_OUTPUT ("b->current_length = %u, "
+		       "b->current_data = %p "
+		       "data_len = %u",
+		       b->current_length, b->current_data, data_len);
+
+  u16 data_padding = vnet_sctp_calculate_padding (b->current_length);
+  if (data_padding > 0)
+    {
+      u8 *p_tail = vlib_buffer_put_uninit (b, data_padding);
+      clib_memset_u8 (p_tail, 0, data_padding);
+    }
+
+  u16 bytes_to_add = sizeof (sctp_payload_data_chunk_t);
+  u16 chunk_length = data_len + bytes_to_add - sizeof (sctp_header_t);
+
+  sctp_payload_data_chunk_t *data_chunk =
+    vlib_buffer_push_uninit (b, bytes_to_add);
+
+  u8 idx = sctp_data_subconn_select (sctp_conn);
+  SCTP_DBG_OUTPUT
+    ("SCTP_CONN = %p, IDX = %u, S_INDEX = %u, C_INDEX = %u, sctp_conn->[...].LCL_PORT = %u, sctp_conn->[...].RMT_PORT = %u",
+     sctp_conn, idx, sctp_conn->sub_conn[idx].connection.s_index,
+     sctp_conn->sub_conn[idx].connection.c_index,
+     sctp_conn->sub_conn[idx].connection.lcl_port,
+     sctp_conn->sub_conn[idx].connection.rmt_port);
+  data_chunk->sctp_hdr.checksum = 0;
+  data_chunk->sctp_hdr.src_port =
+    sctp_conn->sub_conn[idx].connection.lcl_port;
+  data_chunk->sctp_hdr.dst_port =
+    sctp_conn->sub_conn[idx].connection.rmt_port;
+  data_chunk->sctp_hdr.verification_tag = sctp_conn->remote_tag;
+
+  data_chunk->tsn = clib_host_to_net_u32 (sctp_conn->next_tsn);
+  data_chunk->stream_id = clib_host_to_net_u16 (0);
+  data_chunk->stream_seq = clib_host_to_net_u16 (0);
+
+  vnet_sctp_set_chunk_type (&data_chunk->chunk_hdr, DATA);
+  vnet_sctp_set_chunk_length (&data_chunk->chunk_hdr, chunk_length);
+
+  vnet_sctp_set_bbit (&data_chunk->chunk_hdr);
+  vnet_sctp_set_ebit (&data_chunk->chunk_hdr);
+
+  SCTP_ADV_DBG_OUTPUT ("POINTER_WITH_DATA = %p, DATA_OFFSET = %u",
+		       b->data, b->current_data);
+
+  if (sctp_conn->sub_conn[idx].state != SCTP_SUBCONN_AWAITING_SACK)
+    {
+      sctp_conn->sub_conn[idx].state = SCTP_SUBCONN_AWAITING_SACK;
+      sctp_conn->last_unacked_tsn = sctp_conn->next_tsn;
+    }
+
+  sctp_conn->next_tsn += data_len;
+
+  u32 inflight = sctp_conn->next_tsn - sctp_conn->last_unacked_tsn;
+  /* Section 7.2.2; point (3) */
+  if (sctp_conn->sub_conn[idx].partially_acked_bytes >=
+      sctp_conn->sub_conn[idx].cwnd
+      && inflight >= sctp_conn->sub_conn[idx].cwnd)
+    {
+      sctp_conn->sub_conn[idx].cwnd += sctp_conn->sub_conn[idx].PMTU;
+      sctp_conn->sub_conn[idx].partially_acked_bytes -=
+	sctp_conn->sub_conn[idx].cwnd;
+    }
+
+  sctp_conn->sub_conn[idx].last_data_ts = sctp_time_now ();
+
+  sctp_buffer_opaque (b)->sctp.connection_index =
+    sctp_conn->sub_conn[idx].connection.c_index;
+
+  sctp_buffer_opaque (b)->sctp.subconn_idx = idx;
+}
+
+u32
+sctp_push_header (transport_connection_t * trans_conn, vlib_buffer_t * b)
+{
+  sctp_connection_t *sctp_conn =
+    sctp_get_connection_from_transport (trans_conn);
+
+  SCTP_DBG_OUTPUT ("TRANS_CONN = %p, SCTP_CONN = %p, "
+		   "S_INDEX = %u, C_INDEX = %u,"
+		   "trans_conn->LCL_PORT = %u, trans_conn->RMT_PORT = %u",
+		   trans_conn,
+		   sctp_conn,
+		   trans_conn->s_index,
+		   trans_conn->c_index,
+		   trans_conn->lcl_port, trans_conn->rmt_port);
+
+  sctp_push_hdr_i (sctp_conn, b, SCTP_STATE_ESTABLISHED);
+
+  sctp_trajectory_add_start (b, 3);
+
+  return 0;
+}
+
+u32
+sctp_prepare_data_retransmit (sctp_connection_t * sctp_conn,
+			      u8 idx,
+			      u32 offset,
+			      u32 max_deq_bytes, vlib_buffer_t ** b)
+{
+  sctp_main_t *tm = vnet_get_sctp_main ();
+  vlib_main_t *vm = vlib_get_main ();
+  int n_bytes = 0;
+  u32 bi, available_bytes, seg_size;
+  u8 *data;
+
+  ASSERT (sctp_conn->state >= SCTP_STATE_ESTABLISHED);
+  ASSERT (max_deq_bytes != 0);
+
+  /*
+   * Make sure we can retransmit something
+   */
+  available_bytes =
+    transport_max_tx_dequeue (&sctp_conn->sub_conn[idx].connection);
+  ASSERT (available_bytes >= offset);
+  available_bytes -= offset;
+  if (!available_bytes)
+    return 0;
+  max_deq_bytes = clib_min (sctp_conn->sub_conn[idx].cwnd, max_deq_bytes);
+  max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
+
+  seg_size = max_deq_bytes;
+
+  /*
+   * Allocate and fill in buffer(s)
+   */
+
+  if (PREDICT_FALSE (sctp_get_free_buffer_index (tm, &bi)))
+    return 0;
+  *b = vlib_get_buffer (vm, bi);
+  data = sctp_init_buffer (vm, *b);
+
+  /* Easy case, buffer size greater than mss */
+  if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer))
+    {
+      n_bytes =
+	session_tx_fifo_peek_bytes (&sctp_conn->sub_conn[idx].connection,
+				    data, offset, max_deq_bytes);
+      ASSERT (n_bytes == max_deq_bytes);
+      b[0]->current_length = n_bytes;
+      sctp_push_hdr_i (sctp_conn, *b, sctp_conn->state);
+    }
+
+  return n_bytes;
+}
+
+void
+sctp_data_retransmit (sctp_connection_t * sctp_conn)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  vlib_buffer_t *b = 0;
+  u32 bi, n_bytes = 0;
+
+  u8 idx = sctp_data_subconn_select (sctp_conn);
+
+  SCTP_DBG_OUTPUT
+    ("SCTP_CONN = %p, IDX = %u, S_INDEX = %u, C_INDEX = %u, sctp_conn->[...].LCL_PORT = %u, sctp_conn->[...].RMT_PORT = %u",
+     sctp_conn, idx, sctp_conn->sub_conn[idx].connection.s_index,
+     sctp_conn->sub_conn[idx].connection.c_index,
+     sctp_conn->sub_conn[idx].connection.lcl_port,
+     sctp_conn->sub_conn[idx].connection.rmt_port);
+
+  if (sctp_conn->state >= SCTP_STATE_ESTABLISHED)
+    {
+      return;
+    }
+
+  n_bytes =
+    sctp_prepare_data_retransmit (sctp_conn, idx, 0,
+				  sctp_conn->sub_conn[idx].cwnd, &b);
+  if (n_bytes > 0)
+    SCTP_DBG_OUTPUT ("We have data (%u bytes) to retransmit", n_bytes);
+
+  bi = vlib_get_buffer_index (vm, b);
+
+  sctp_enqueue_to_output_now (vm, b, bi,
+			      sctp_conn->sub_conn[idx].connection.is_ip4);
+
+  return;
+}
+
+#if SCTP_DEBUG_STATE_MACHINE
+always_inline u8
+sctp_validate_output_state_machine (sctp_connection_t * sctp_conn,
+				    u8 chunk_type)
+{
+  u8 result = 0;
+  switch (sctp_conn->state)
+    {
+    case SCTP_STATE_CLOSED:
+      if (chunk_type != INIT && chunk_type != INIT_ACK)
+	result = 1;
+      break;
+    case SCTP_STATE_ESTABLISHED:
+      if (chunk_type != DATA && chunk_type != HEARTBEAT &&
+	  chunk_type != HEARTBEAT_ACK && chunk_type != SACK &&
+	  chunk_type != COOKIE_ACK && chunk_type != SHUTDOWN)
+	result = 1;
+      break;
+    case SCTP_STATE_COOKIE_WAIT:
+      if (chunk_type != COOKIE_ECHO)
+	result = 1;
+      break;
+    case SCTP_STATE_SHUTDOWN_SENT:
+      if (chunk_type != SHUTDOWN_COMPLETE)
+	result = 1;
+      break;
+    case SCTP_STATE_SHUTDOWN_RECEIVED:
+      if (chunk_type != SHUTDOWN_ACK)
+	result = 1;
+      break;
+    }
+  return result;
+}
+#endif
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp_output_node.c b/src/plugins/sctp/sctp_output_node.c
new file mode 100644
index 00000000000..7bf2e896acc
--- /dev/null
+++ b/src/plugins/sctp/sctp_output_node.c
@@ -0,0 +1,397 @@
+/*
+ * Copyright (c) 2018 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <sctp/sctp.h>
+#include <sctp/sctp_debug.h>
+#include <vppinfra/random.h>
+#include <openssl/hmac.h>
+
+u32
+ip6_sctp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
+			   ip6_header_t * ip0, int *bogus_lengthp);
+
+u32
+ip4_sctp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0,
+			   ip4_header_t * ip0);
+
+#define foreach_sctp4_output_next              	\
+  _ (DROP, "error-drop")                        \
+  _ (IP_LOOKUP, "ip4-lookup")
+
+#define foreach_sctp6_output_next              	\
+  _ (DROP, "error-drop")                        \
+  _ (IP_LOOKUP, "ip6-lookup")
+
+static char *sctp_error_strings[] = {
+#define sctp_error(n,s) s,
+#include <sctp/sctp_error.def>
+#undef sctp_error
+};
+
+typedef enum _sctp_output_next
+{
+  SCTP_OUTPUT_NEXT_DROP,
+  SCTP_OUTPUT_NEXT_IP_LOOKUP,
+  SCTP_OUTPUT_N_NEXT
+} sctp_output_next_t;
+
+typedef struct
+{
+  sctp_header_t sctp_header;
+  sctp_connection_t sctp_connection;
+} sctp_tx_trace_t;
+
+always_inline u8
+sctp_is_retransmitting (sctp_connection_t * sctp_conn, u8 idx)
+{
+  return sctp_conn->sub_conn[idx].is_retransmitting;
+}
+
+always_inline uword
+sctp46_output_inline (vlib_main_t * vm,
+		      vlib_node_runtime_t * node,
+		      vlib_frame_t * from_frame, int is_ip4)
+{
+  u32 n_left_from, next_index, *from, *to_next;
+  u32 my_thread_index = vm->thread_index;
+
+  from = vlib_frame_vector_args (from_frame);
+  n_left_from = from_frame->n_vectors;
+  next_index = node->cached_next_index;
+  sctp_set_time_now (my_thread_index);
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  sctp_header_t *sctp_hdr = 0;
+	  sctp_connection_t *sctp_conn;
+	  sctp_tx_trace_t *t0;
+	  sctp_header_t *th0 = 0;
+	  u32 error0 = SCTP_ERROR_PKTS_SENT, next0 =
+	    SCTP_OUTPUT_NEXT_IP_LOOKUP;
+
+#if SCTP_DEBUG_STATE_MACHINE
+	  u16 packet_length = 0;
+#endif
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+
+	  sctp_conn =
+	    sctp_connection_get (sctp_buffer_opaque (b0)->
+				 sctp.connection_index, my_thread_index);
+
+	  if (PREDICT_FALSE (sctp_conn == 0))
+	    {
+	      error0 = SCTP_ERROR_INVALID_CONNECTION;
+	      next0 = SCTP_OUTPUT_NEXT_DROP;
+	      goto done;
+	    }
+
+	  u8 idx = sctp_buffer_opaque (b0)->sctp.subconn_idx;
+
+	  th0 = vlib_buffer_get_current (b0);
+
+	  if (is_ip4)
+	    {
+	      ip4_header_t *iph4 = vlib_buffer_push_ip4 (vm,
+							 b0,
+							 &sctp_conn->sub_conn
+							 [idx].connection.
+							 lcl_ip.ip4,
+							 &sctp_conn->
+							 sub_conn
+							 [idx].connection.
+							 rmt_ip.ip4,
+							 IP_PROTOCOL_SCTP, 1);
+
+	      u32 checksum = ip4_sctp_compute_checksum (vm, b0, iph4);
+
+	      sctp_hdr = ip4_next_header (iph4);
+	      sctp_hdr->checksum = checksum;
+
+	      vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
+
+#if SCTP_DEBUG_STATE_MACHINE
+	      packet_length = clib_net_to_host_u16 (iph4->length);
+#endif
+	    }
+	  else
+	    {
+	      ip6_header_t *iph6 = vlib_buffer_push_ip6 (vm,
+							 b0,
+							 &sctp_conn->sub_conn
+							 [idx].
+							 connection.lcl_ip.
+							 ip6,
+							 &sctp_conn->sub_conn
+							 [idx].
+							 connection.rmt_ip.
+							 ip6,
+							 IP_PROTOCOL_SCTP);
+
+	      int bogus = ~0;
+	      u32 checksum = ip6_sctp_compute_checksum (vm, b0, iph6, &bogus);
+	      ASSERT (!bogus);
+
+	      sctp_hdr = ip6_next_header (iph6);
+	      sctp_hdr->checksum = checksum;
+
+	      vnet_buffer (b0)->l3_hdr_offset = (u8 *) iph6 - b0->data;
+	      vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;
+
+#if SCTP_DEBUG_STATE_MACHINE
+	      packet_length = clib_net_to_host_u16 (iph6->payload_length);
+#endif
+	    }
+
+	  sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
+	  u8 chunk_type = vnet_sctp_get_chunk_type (&full_hdr->common_hdr);
+	  if (chunk_type >= UNKNOWN)
+	    {
+	      clib_warning
+		("Trying to send an unrecognized chunk... something is really bad.");
+	      error0 = SCTP_ERROR_UNKNOWN_CHUNK;
+	      next0 = SCTP_OUTPUT_NEXT_DROP;
+	      goto done;
+	    }
+
+#if SCTP_DEBUG_STATE_MACHINE
+	  u8 is_valid =
+	    (sctp_conn->sub_conn[idx].connection.lcl_port ==
+	     sctp_hdr->src_port
+	     || sctp_conn->sub_conn[idx].connection.lcl_port ==
+	     sctp_hdr->dst_port)
+	    && (sctp_conn->sub_conn[idx].connection.rmt_port ==
+		sctp_hdr->dst_port
+		|| sctp_conn->sub_conn[idx].connection.rmt_port ==
+		sctp_hdr->src_port);
+
+	  if (!is_valid)
+	    {
+	      SCTP_DBG_STATE_MACHINE ("BUFFER IS INCORRECT: conn_index = %u, "
+				      "packet_length = %u, "
+				      "chunk_type = %u [%s], "
+				      "connection.lcl_port = %u, sctp_hdr->src_port = %u, "
+				      "connection.rmt_port = %u, sctp_hdr->dst_port = %u",
+				      sctp_conn->sub_conn[idx].
+				      connection.c_index, packet_length,
+				      chunk_type,
+				      sctp_chunk_to_string (chunk_type),
+				      sctp_conn->sub_conn[idx].
+				      connection.lcl_port, sctp_hdr->src_port,
+				      sctp_conn->sub_conn[idx].
+				      connection.rmt_port,
+				      sctp_hdr->dst_port);
+
+	      error0 = SCTP_ERROR_UNKNOWN_CHUNK;
+	      next0 = SCTP_OUTPUT_NEXT_DROP;
+	      goto done;
+	    }
+#endif
+	  SCTP_DBG_STATE_MACHINE
+	    ("SESSION_INDEX = %u, CONN_INDEX = %u, CURR_CONN_STATE = %u (%s), "
+	     "CHUNK_TYPE = %s, " "SRC_PORT = %u, DST_PORT = %u",
+	     sctp_conn->sub_conn[idx].connection.s_index,
+	     sctp_conn->sub_conn[idx].connection.c_index,
+	     sctp_conn->state, sctp_state_to_string (sctp_conn->state),
+	     sctp_chunk_to_string (chunk_type), full_hdr->hdr.src_port,
+	     full_hdr->hdr.dst_port);
+
+	  /* Let's make sure the state-machine does not send anything crazy */
+#if SCTP_DEBUG_STATE_MACHINE
+	  if (sctp_validate_output_state_machine (sctp_conn, chunk_type) != 0)
+	    {
+	      SCTP_DBG_STATE_MACHINE
+		("Sending the wrong chunk (%s) based on state-machine status (%s)",
+		 sctp_chunk_to_string (chunk_type),
+		 sctp_state_to_string (sctp_conn->state));
+
+	      error0 = SCTP_ERROR_UNKNOWN_CHUNK;
+	      next0 = SCTP_OUTPUT_NEXT_DROP;
+	      goto done;
+
+	    }
+#endif
+
+	  /* Karn's algorithm: RTT measurements MUST NOT be made using
+	   * packets that were retransmitted
+	   */
+	  if (!sctp_is_retransmitting (sctp_conn, idx))
+	    {
+	      /* Measure RTT with this */
+	      if (chunk_type == DATA
+		  && sctp_conn->sub_conn[idx].RTO_pending == 0)
+		{
+		  sctp_conn->sub_conn[idx].RTO_pending = 1;
+		  sctp_conn->sub_conn[idx].rtt_ts = sctp_time_now ();
+		}
+	      else
+		sctp_conn->sub_conn[idx].rtt_ts = sctp_time_now ();
+	    }
+
+	  /* Let's take care of TIMERS */
+	  switch (chunk_type)
+	    {
+	    case COOKIE_ECHO:
+	      {
+		sctp_conn->state = SCTP_STATE_COOKIE_ECHOED;
+		break;
+	      }
+	    case DATA:
+	      {
+		SCTP_ADV_DBG_OUTPUT ("PACKET_LENGTH = %u", packet_length);
+
+		sctp_timer_update (sctp_conn, idx, SCTP_TIMER_T3_RXTX,
+				   sctp_conn->sub_conn[idx].RTO);
+		break;
+	      }
+	    case SHUTDOWN:
+	      {
+		/* Start the SCTP_TIMER_T2_SHUTDOWN timer */
+		sctp_timer_set (sctp_conn, idx, SCTP_TIMER_T2_SHUTDOWN,
+				sctp_conn->sub_conn[idx].RTO);
+		sctp_conn->state = SCTP_STATE_SHUTDOWN_SENT;
+		break;
+	      }
+	    case SHUTDOWN_ACK:
+	      {
+		/* Start the SCTP_TIMER_T2_SHUTDOWN timer */
+		sctp_timer_set (sctp_conn, idx, SCTP_TIMER_T2_SHUTDOWN,
+				sctp_conn->sub_conn[idx].RTO);
+		sctp_conn->state = SCTP_STATE_SHUTDOWN_ACK_SENT;
+		break;
+	      }
+	    case SHUTDOWN_COMPLETE:
+	      {
+		sctp_conn->state = SCTP_STATE_CLOSED;
+		break;
+	      }
+	    }
+
+	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
+	  vnet_buffer (b0)->sw_if_index[VLIB_TX] =
+	    sctp_conn->sub_conn[idx].c_fib_index;
+
+	  b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
+
+	  SCTP_DBG_STATE_MACHINE
+	    ("SESSION_INDEX = %u, CONNECTION_INDEX = %u, " "NEW_STATE = %s, "
+	     "CHUNK_SENT = %s", sctp_conn->sub_conn[idx].connection.s_index,
+	     sctp_conn->sub_conn[idx].connection.c_index,
+	     sctp_state_to_string (sctp_conn->state),
+	     sctp_chunk_to_string (chunk_type));
+
+	  vnet_sctp_common_hdr_params_host_to_net (&full_hdr->common_hdr);
+
+	done:
+	  b0->error = node->errors[error0];
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
+	      if (th0)
+		{
+		  clib_memcpy_fast (&t0->sctp_header, th0,
+				    sizeof (t0->sctp_header));
+		}
+	      else
+		{
+		  clib_memset (&t0->sctp_header, 0, sizeof (t0->sctp_header));
+		}
+	      clib_memcpy_fast (&t0->sctp_connection, sctp_conn,
+				sizeof (t0->sctp_connection));
+	    }
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  return from_frame->n_vectors;
+}
+
+VLIB_NODE_FN (sctp4_output_node) (vlib_main_t * vm,
+				  vlib_node_runtime_t * node,
+				  vlib_frame_t * from_frame)
+{
+  return sctp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ );
+}
+
+VLIB_NODE_FN (sctp6_output_node) (vlib_main_t * vm,
+				  vlib_node_runtime_t * node,
+				  vlib_frame_t * from_frame)
+{
+  return sctp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ );
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp4_output_node) =
+{
+    .name = "sctp4-output",
+    /* Takes a vector of packets. */
+    .vector_size = sizeof (u32),
+    .n_errors = SCTP_N_ERROR,
+    .error_strings = sctp_error_strings,
+    .n_next_nodes = SCTP_OUTPUT_N_NEXT,
+    .next_nodes = {
+#define _(s,n) [SCTP_OUTPUT_NEXT_##s] = n,
+    foreach_sctp4_output_next
+#undef _
+    },
+    .format_buffer = format_sctp_header,
+    .format_trace = format_sctp_tx_trace,
+};
+/* *INDENT-ON* */
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (sctp6_output_node) =
+{
+  .name = "sctp6-output",
+    /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+  .n_errors = SCTP_N_ERROR,
+  .error_strings = sctp_error_strings,
+  .n_next_nodes = SCTP_OUTPUT_N_NEXT,
+  .next_nodes = {
+#define _(s,n) [SCTP_OUTPUT_NEXT_##s] = n,
+    foreach_sctp6_output_next
+#undef _
+  },
+  .format_buffer = format_sctp_header,
+  .format_trace = format_sctp_tx_trace,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp_packet.h b/src/plugins/sctp/sctp_packet.h
new file mode 100644
index 00000000000..04995aa7ee3
--- /dev/null
+++ b/src/plugins/sctp/sctp_packet.h
@@ -0,0 +1,1470 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_vnet_sctp_packet_h
+#define included_vnet_sctp_packet_h
+
+#include <stdbool.h>
+
+#include <vnet/ip/ip4_packet.h>
+#include <vnet/ip/ip6_packet.h>
+
+/*
+ * As per RFC 4960
+ * https://tools.ietf.org/html/rfc4960
+ */
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |     Source Port Number        |     Destination Port Number   |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                      Verification Tag                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                           Checksum                            |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  /*
+   * This is the SCTP sender's port number. It can be used by the
+   * receiver in combination with the source IP address, the SCTP
+   * destination port, and possibly the destination IP address to
+   * identify the association to which this packet belongs.
+   * The port number 0 MUST NOT be used.
+   */
+  u16 src_port;
+
+  /*
+   * This is the SCTP port number to which this packet is destined.
+   * The receiving host will use this port number to de-multiplex the
+   * SCTP packet to the correct receiving endpoint/application.
+   * The port number 0 MUST NOT be used.
+   */
+  u16 dst_port;
+
+  /*
+   * The receiver of this packet uses the Verification Tag to validate
+   * the sender of this SCTP packet.  On transmit, the value of this
+   * Verification Tag MUST be set to the value of the Initiate Tag
+   * received from the peer endpoint during the association
+   * initialization, with the following exceptions:
+   * - A packet containing an INIT chunk MUST have a zero Verification
+   *   Tag.
+   * - A packet containing a SHUTDOWN COMPLETE chunk with the T bit
+   *   set MUST have the Verification Tag copied from the packet with
+   *   the SHUTDOWN ACK chunk.
+   * - A packet containing an ABORT chunk may have the verification tag
+   *   copied from the packet that caused the ABORT to be sent.
+   * An INIT chunk MUST be the only chunk in the SCTP packet carrying it.
+   */
+  u32 verification_tag;
+
+  /*
+   * This field contains the checksum of this SCTP packet.
+   * SCTP uses the CRC32c algorithm.
+   */
+  u32 checksum;
+
+} sctp_header_t;
+
+always_inline void
+vnet_set_sctp_src_port (sctp_header_t * h, u16 src_port)
+{
+  h->src_port = clib_host_to_net_u16 (src_port);
+}
+
+always_inline u16
+vnet_get_sctp_src_port (sctp_header_t * h)
+{
+  return (clib_net_to_host_u16 (h->src_port));
+}
+
+always_inline void
+vnet_set_sctp_dst_port (sctp_header_t * h, u16 dst_port)
+{
+  h->dst_port = clib_host_to_net_u16 (dst_port);
+}
+
+always_inline u16
+vnet_get_sctp_dst_port (sctp_header_t * h)
+{
+  return (clib_net_to_host_u16 (h->dst_port));
+}
+
+always_inline void
+vnet_set_sctp_verification_tag (sctp_header_t * h, u32 verification_tag)
+{
+  h->verification_tag = clib_host_to_net_u32 (verification_tag);
+}
+
+always_inline u32
+vnet_get_sctp_verification_tag (sctp_header_t * h)
+{
+  return (clib_net_to_host_u32 (h->verification_tag));
+}
+
+always_inline void
+vnet_set_sctp_checksum (sctp_header_t * h, u32 checksum)
+{
+  h->checksum = clib_host_to_net_u32 (checksum);
+}
+
+always_inline u32
+vnet_get_sctp_checksum (sctp_header_t * h)
+{
+  return (clib_net_to_host_u32 (h->checksum));
+}
+
+/*
+ * Multiple chunks can be bundled into one SCTP packet up to the MTU
+ * size, except for the INIT, INIT ACK, and SHUTDOWN COMPLETE chunks.
+ * These chunks MUST NOT be bundled with any other chunk in a packet.
+ *
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                        Common Header                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                          Chunk #1                             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                           ...                                 |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                          Chunk #n                             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+
+typedef enum
+{
+  DATA = 0,
+  INIT,
+  INIT_ACK,
+  SACK,
+  HEARTBEAT,
+  HEARTBEAT_ACK,
+  ABORT,
+  SHUTDOWN,
+  SHUTDOWN_ACK,
+  OPERATION_ERROR,
+  COOKIE_ECHO,
+  COOKIE_ACK,
+  ECNE,
+  CWR,
+  SHUTDOWN_COMPLETE,
+  UNKNOWN
+} sctp_chunk_type;
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Chunk Type  | Chunk  Flags  |        Chunk Length           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  /*
+   * This field identifies the type of information contained in the
+   * Chunk Value field. It takes a value from 0 to 254.
+   * The value of 255 is reserved for future use as an extension field.
+   *
+   * The values of Chunk Types are defined as follows:
+   * ID Value    Chunk Type
+   * -----       ----------
+   *  0          - Payload Data (DATA)
+   *  1          - Initiation (INIT)
+   *  2          - Initiation Acknowledgement (INIT ACK)
+   *  3          - Selective Acknowledgement (SACK)
+   *  4          - Heartbeat Request (HEARTBEAT)
+   *  5          - Heartbeat Acknowledgement (HEARTBEAT ACK)
+   *  6          - Abort (ABORT)
+   *  7          - Shutdown (SHUTDOWN)
+   *  8          - Shutdown Acknowledgement (SHUTDOWN ACK)
+   *  9          - Operation Error (ERROR)
+   *  10         - State Cookie (COOKIE ECHO)
+   *  11         - Cookie Acknowledgement (COOKIE ACK)
+   *  12         - Reserved for Explicit Congestion Notification Echo (ECNE)
+   *  13         - Reserved for Congestion Window Reduced (CWR)
+   *  14         - Shutdown Complete (SHUTDOWN COMPLETE)
+   *  15 to 62   - available
+   *  63         - reserved for IETF-defined Chunk Extensions
+   *  64 to 126  - available
+   *  127        - reserved for IETF-defined Chunk Extensions
+   *  128 to 190 - available
+   *  191        - reserved for IETF-defined Chunk Extensions
+   *  192 to 254 - available
+   *  255        - reserved for IETF-defined Chunk Extensions
+   *
+   *  Chunk Types are encoded such that the highest-order 2 bits specify
+   *  the action that must be taken if the processing endpoint does not
+   *  recognize the Chunk Type.
+   *  00 -  Stop processing this SCTP packet and discard it, do not
+   *  process any further chunks within it.
+   *  01 -  Stop processing this SCTP packet and discard it, do not
+   *  process any further chunks within it, and report the
+   *  unrecognized chunk in an 'Unrecognized Chunk Type'.
+   *  10 -  Skip this chunk and continue processing.
+   *  11 -  Skip this chunk and continue processing, but report in an
+   *  ERROR chunk using the 'Unrecognized Chunk Type' cause of error.
+   *
+   *  Note: The ECNE and CWR chunk types are reserved for future use of
+   *  Explicit Congestion Notification (ECN);
+   */
+  //u8 type;
+
+  /*
+   * The usage of these bits depends on the Chunk type as given by the
+   * Chunk Type field.  Unless otherwise specified, they are set to 0 on
+   * transmit and are ignored on receipt.
+   */
+  //u8 flags;
+
+  /*
+   * This value represents the size of the chunk in bytes, including
+   * the Chunk Type, Chunk Flags, Chunk Length, and Chunk Value fields.
+   * Therefore, if the Chunk Value field is zero-length, the Length
+   * field will be set to 4.
+   * The Chunk Length field does not count any chunk padding.
+   * Chunks (including Type, Length, and Value fields) are padded out
+   * by the sender with all zero bytes to be a multiple of 4 bytes
+   * long. This padding MUST NOT be more than 3 bytes in total. The
+   * Chunk Length value does not include terminating padding of the
+   * chunk. However, it does include padding of any variable-length
+   * parameter except the last parameter in the chunk. The receiver
+   * MUST ignore the padding.
+   *
+   * Note: A robust implementation should accept the chunk whether or
+   * not the final padding has been included in the Chunk Length.
+   */
+  //u16 length;
+
+  u32 params;
+
+} sctp_chunks_common_hdr_t;
+
+typedef struct
+{
+  sctp_header_t hdr;
+  sctp_chunks_common_hdr_t common_hdr;
+
+} sctp_full_hdr_t;
+
+#define CHUNK_TYPE_MASK 0xFF000000
+#define CHUNK_TYPE_SHIFT 24
+
+#define CHUNK_FLAGS_MASK 0x00FF0000
+#define CHUNK_FLAGS_SHIFT 16
+
+#define CHUNK_UBIT_MASK 0x00040000
+#define CHUNK_UBIT_SHIFT 18
+
+#define CHUNK_BBIT_MASK 0x00020000
+#define CHUNK_BBIT_SHIFT 17
+
+#define CHUNK_EBIT_MASK 0x00010000
+#define CHUNK_EBIT_SHIFT 16
+
+#define CHUNK_LENGTH_MASK 0x0000FFFF
+#define CHUNK_LENGTH_SHIFT 0
+
+always_inline void
+vnet_sctp_common_hdr_params_host_to_net (sctp_chunks_common_hdr_t * h)
+{
+  h->params = clib_host_to_net_u32 (h->params);
+}
+
+always_inline void
+vnet_sctp_common_hdr_params_net_to_host (sctp_chunks_common_hdr_t * h)
+{
+  h->params = clib_net_to_host_u32 (h->params);
+}
+
+always_inline void
+vnet_sctp_set_ubit (sctp_chunks_common_hdr_t * h)
+{
+  h->params &= ~(CHUNK_UBIT_MASK);
+  h->params |= (1 << CHUNK_UBIT_SHIFT) & CHUNK_UBIT_MASK;
+}
+
+always_inline u8
+vnet_sctp_get_ubit (sctp_chunks_common_hdr_t * h)
+{
+  return ((h->params & CHUNK_UBIT_MASK) >> CHUNK_UBIT_SHIFT);
+}
+
+always_inline void
+vnet_sctp_set_bbit (sctp_chunks_common_hdr_t * h)
+{
+  h->params &= ~(CHUNK_BBIT_MASK);
+  h->params |= (1 << CHUNK_BBIT_SHIFT) & CHUNK_BBIT_MASK;
+}
+
+always_inline u8
+vnet_sctp_get_bbit (sctp_chunks_common_hdr_t * h)
+{
+  return ((h->params & CHUNK_BBIT_MASK) >> CHUNK_BBIT_SHIFT);
+}
+
+always_inline void
+vnet_sctp_set_ebit (sctp_chunks_common_hdr_t * h)
+{
+  h->params &= ~(CHUNK_EBIT_MASK);
+  h->params |= (1 << CHUNK_EBIT_SHIFT) & CHUNK_EBIT_MASK;
+}
+
+always_inline u8
+vnet_sctp_get_ebit (sctp_chunks_common_hdr_t * h)
+{
+  return ((h->params & CHUNK_EBIT_MASK) >> CHUNK_EBIT_SHIFT);
+}
+
+always_inline void
+vnet_sctp_set_chunk_type (sctp_chunks_common_hdr_t * h, sctp_chunk_type t)
+{
+  h->params &= ~(CHUNK_TYPE_MASK);
+  h->params |= (t << CHUNK_TYPE_SHIFT) & CHUNK_TYPE_MASK;
+}
+
+always_inline u8
+vnet_sctp_get_chunk_type (sctp_chunks_common_hdr_t * h)
+{
+  return ((h->params & CHUNK_TYPE_MASK) >> CHUNK_TYPE_SHIFT);
+}
+
+always_inline void
+vnet_sctp_set_chunk_length (sctp_chunks_common_hdr_t * h, u16 length)
+{
+  h->params &= ~(CHUNK_LENGTH_MASK);
+  h->params |= (length << CHUNK_LENGTH_SHIFT) & CHUNK_LENGTH_MASK;
+}
+
+always_inline u16
+vnet_sctp_get_chunk_length (sctp_chunks_common_hdr_t * h)
+{
+  return ((h->params & CHUNK_LENGTH_MASK) >> CHUNK_LENGTH_SHIFT);
+}
+
+/*
+ * Payload chunk
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 0    | Reserved|U|B|E|    Length                     |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                              TSN                              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |      Stream Identifier S      |   Stream Sequence Number n    |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                  Payload Protocol Identifier                  |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /                 User Data (seq n of Stream S)                 /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  /*
+   * Type (8 bits): 0
+   * Flags (8 bits):
+   * -- Reserved (5 bits): all 0s
+   * -- U bit
+   * -- B bit
+   * -- E bit
+   * Length (16 bits): This field indicates the length of the DATA chunk in
+   * bytes from the beginning of the type field to the end of the User Data
+   * field excluding any padding.
+   * A DATA chunk with one byte of user data will have Length set to 17
+   * (indicating 17 bytes). A DATA chunk with a User Data field of length L
+   * will have the Length field set to (16 + L) (indicating 16+L bytes) where
+   * L MUST be greater than 0.
+   */
+
+  /*
+   * Fragment Description Table:
+   *
+   *    B E                  Description
+   * ============================================================
+   * |  1 0 | First piece of a fragmented user message          |
+   * +----------------------------------------------------------+
+   * |  0 0 | Middle piece of a fragmented user message         |
+   * +----------------------------------------------------------+
+   * |  0 1 | Last piece of a fragmented user message           |
+   * +----------------------------------------------------------+
+   * |  1 1 | Unfragmented message                              |
+   * ============================================================
+   */
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+  /*
+   * This value represents the TSN for this DATA chunk.
+   * The valid range of TSN is from 0 to 4294967295 (2**32 - 1).
+   * TSN wraps back to 0 after reaching 4294967295.
+   */
+  u32 tsn;
+
+  /*
+   * Identifies the stream to which the following user data belongs.
+   */
+  u16 stream_id;
+
+  /*
+   * This value represents the Stream Sequence Number of the following user data
+   * within the stream S. Valid range is 0 to 65535.
+   * When a user message is fragmented by SCTP for transport, the same Stream
+   * Sequence Number MUST be carried in each of the fragments of the message.
+   */
+  u16 stream_seq;
+
+  /*
+   * This value represents an application (or upper layer) specified protocol
+   * identifier. This value is passed to SCTP by its upper layer and sent to its
+   * peer. This identifier is not used by SCTP but can be used by certain network
+   * entities, as well as by the peer application, to identify the type of
+   * information being carried in this DATA chunk. This field must be sent even
+   * in fragmented DATA chunks (to make sure it is available for agents in the
+   * middle of the network).  Note that this field is NOT touched by an SCTP
+   * implementation; therefore, its byte order is NOT necessarily big endian.
+   * The upper layer is responsible for any byte order conversions to this field.
+   * The value 0 indicates that no application identifier is specified by the
+   * upper layer for this payload data.
+   */
+  u32 payload_id;
+
+  /*
+   * This is the payload user data. The implementation MUST pad the end of the
+   * data to a 4-byte boundary with all-zero bytes. Any padding MUST NOT be
+   * included in the Length field. A sender MUST never add more than 3 bytes of
+   * padding.
+   */
+  u32 data[];
+
+} sctp_payload_data_chunk_t;
+
+always_inline void
+vnet_sctp_set_tsn (sctp_payload_data_chunk_t * p, u32 tsn)
+{
+  p->tsn = clib_host_to_net_u32 (tsn);
+}
+
+always_inline u32
+vnet_sctp_get_tsn (sctp_payload_data_chunk_t * p)
+{
+  return (clib_net_to_host_u32 (p->tsn));
+}
+
+always_inline void
+vnet_sctp_set_stream_id (sctp_payload_data_chunk_t * p, u16 stream_id)
+{
+  p->stream_id = clib_host_to_net_u16 (stream_id);
+}
+
+always_inline u16
+vnet_sctp_get_stream_id (sctp_payload_data_chunk_t * p)
+{
+  return (clib_net_to_host_u16 (p->stream_id));
+}
+
+always_inline void
+vnet_sctp_set_stream_seq (sctp_payload_data_chunk_t * p, u16 stream_seq)
+{
+  p->stream_seq = clib_host_to_net_u16 (stream_seq);
+}
+
+always_inline u16
+vnet_sctp_get_stream_seq (sctp_payload_data_chunk_t * p)
+{
+  return (clib_net_to_host_u16 (p->stream_seq));
+}
+
+always_inline void
+vnet_sctp_set_payload_id (sctp_payload_data_chunk_t * p, u32 payload_id)
+{
+  p->payload_id = clib_host_to_net_u32 (payload_id);
+}
+
+always_inline u32
+vnet_sctp_get_payload_id (sctp_payload_data_chunk_t * p)
+{
+  return (clib_net_to_host_u32 (p->payload_id));
+}
+
+always_inline u16
+vnet_sctp_calculate_padding (u16 base_length)
+{
+  if (base_length % 4 == 0)
+    return 0;
+
+  return (4 - base_length % 4);
+}
+
+#define INBOUND_STREAMS_COUNT 1
+#define OUTBOUND_STREAMS_COUNT 1
+
+/*
+ * INIT chunk
+ *
+ * This chunk is used to initiate an SCTP association between two
+ * endpoints.
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 1    |  Chunk Flags  |      Chunk Length             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                         Initiate Tag                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |           Advertised Receiver Window Credit (a_rwnd)          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |  Number of Outbound Streams   |  Number of Inbound Streams    |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                          Initial TSN                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /              Optional/Variable-Length Parameters              /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * The INIT chunk contains the following parameters. Unless otherwise
+ * noted, each parameter MUST only be included once in the INIT chunk.
+ *
+ * Fixed Parameters                     Status
+ * ----------------------------------------------
+ *  Initiate Tag                        Mandatory
+ *  Advertised Receiver Window Credit   Mandatory
+ *  Number of Outbound Streams          Mandatory
+ *  Number of Inbound Streams           Mandatory
+ *  Initial TSN                         Mandatory
+ *
+ * Variable Parameters                  Status     Type Value
+ * -------------------------------------------------------------
+ *  IPv4 Address (Note 1)               Optional    5
+ *  IPv6 Address (Note 1)               Optional    6
+ *  Cookie Preservative			Optional    9
+ *  Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
+ *  Host Name Address (Note 3)          Optional    11
+ *  Supported Address Types (Note 4)    Optional    12
+ *
+ * Note 1: The INIT chunks can contain multiple addresses that can be
+ * IPv4 and/or IPv6 in any combination.
+ *
+ * Note 2: The ECN Capable field is reserved for future use of Explicit
+ * Congestion Notification.
+ *
+ * Note 3: An INIT chunk MUST NOT contain more than one Host Name Address
+ * parameter. Moreover, the sender of the INIT MUST NOT combine any other
+ * address types with the Host Name Address in the INIT. The receiver of
+ * INIT MUST ignore any other address types if the Host Name Address parameter
+ * is present in the received INIT chunk.
+ *
+ * Note 4: This parameter, when present, specifies all the address types the
+ * sending endpoint can support.  The absence of this parameter indicates that
+ * the sending endpoint can support any address type.
+ *
+ * IMPLEMENTATION NOTE: If an INIT chunk is received with known parameters that
+ * are not optional parameters of the INIT chunk, then the receiver SHOULD
+ * process the INIT chunk and send back an INIT ACK. The receiver of the INIT
+ * chunk MAY bundle an ERROR chunk with the COOKIE ACK chunk later.
+ * However, restrictive implementations MAY send back an ABORT chunk in response
+ * to the INIT chunk. The Chunk Flags field in INIT is reserved, and all bits
+ * in it should be set to 0 by the sender and ignored by the receiver.
+ * The sequence of parameters within an INIT can be processed in any order.
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+  /*
+   * The receiver of the INIT (the responding end) records the value of
+   * the Initiate Tag parameter.
+   * This value MUST be placed into the Verification Tag field of every
+   * SCTP packet that the receiver of the INIT transmits within this association.
+   * The Initiate Tag is allowed to have any value except 0.
+   *
+   * If the value of the Initiate Tag in a received INIT chunk is found
+   * to be 0, the receiver MUST treat it as an error and close the
+   * association by transmitting an ABORT.
+   *
+   * The value of the INIT TAG is recommended to be random for security
+   * reasons. A good method is described in https://tools.ietf.org/html/rfc4086
+   */
+  u32 initiate_tag;
+
+  /*
+   * This value represents the dedicated buffer space, in number of bytes,
+   * the sender of the INIT has reserved in association with this window.
+   * During the life of the association, this buffer space SHOULD NOT be
+   * lessened (i.e., dedicated buffers taken away from this association);
+   * however, an endpoint MAY change the value of a_rwnd it sends in SACK
+   * chunks.
+   */
+  u32 a_rwnd;
+
+  /*
+   * Defines the number of outbound streams the sender of this INIT chunk
+   * wishes to create in this association.
+   * The value of 0 MUST NOT be used.
+   *
+   * Note: A receiver of an INIT with the OS value set to 0 SHOULD abort
+   * the association.
+   */
+  u16 outbound_streams_count;
+
+  /*
+   * Defines the maximum number of streams the sender of this INIT
+   * chunk allows the peer end to create in this association.
+   * The value 0 MUST NOT be used.
+   *
+   * Note: There is no negotiation of the actual number of streams but
+   * instead the two endpoints will use the min(requested, offered).
+   *
+   * Note: A receiver of an INIT with the MIS value of 0 SHOULD abort
+   * the association.
+   */
+  u16 inboud_streams_count;
+
+  /*
+   * Defines the initial TSN that the sender will use.
+   * The valid range is from 0 to 4294967295.
+   * This field MAY be set to the value of the Initiate Tag field.
+   */
+  u32 initial_tsn;
+
+  /* The following field allows to have multiple optional fields which are:
+   * - sctp_ipv4_address
+   * - sctp_ipv6_address
+   * - sctp_cookie_preservative
+   * - sctp_hostname_address
+   * - sctp_supported_address_types
+   */
+  u32 optional_fields[];
+
+} sctp_init_chunk_t;
+
+/*
+ * INIT ACK chunk
+ *
+ * The INIT ACK chunk is used to acknowledge the initiation of an SCTP
+ * association. The parameter part of INIT ACK is formatted similarly to the
+ * INIT chunk.
+ *
+ * It uses two extra variable parameters:
+ * - the State Cookie and
+ * - the Unrecognized Parameter:
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 2    |  Chunk Flags  |      Chunk Length             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                         Initiate Tag                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |              Advertised Receiver Window Credit                |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |  Number of Outbound Streams   |  Number of Inbound Streams    |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                          Initial TSN                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /              Optional/Variable-Length Parameters              /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef sctp_init_chunk_t sctp_init_ack_chunk_t;
+
+typedef struct
+{
+  u16 type;
+  u16 length;
+
+} sctp_opt_params_hdr_t;
+
+#define SHA1_OUTPUT_LENGTH 20
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Parameter Type       |       Parameter Length        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /                       Parameter Value                         /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  unsigned char mac[SHA1_OUTPUT_LENGTH];	/* RFC 2104 */
+  u64 creation_time;
+  u32 cookie_lifespan;
+
+} sctp_state_cookie_param_t;
+
+/*
+ *  This chunk is used only during the initialization of an association.
+ *  It is sent by the initiator of an association to its peer to complete
+ *  the initialization process.  This chunk MUST precede any DATA chunk
+ *  sent within the association, but MAY be bundled with one or more DATA
+ *  chunks in the same packet.
+ *
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |   Type = 10   |Chunk  Flags   |         Length                |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  /                     Cookie                                    /
+ *  \                                                               \
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+  sctp_state_cookie_param_t cookie;
+
+} sctp_cookie_echo_chunk_t;
+
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 11   |Chunk  Flags   |     Length = 4                |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+} sctp_cookie_ack_chunk_t;
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 14   |Chunk  Flags   |     Length = 4                |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+} sctp_shutdown_complete_chunk_t;
+
+/* OPTIONAL or VARIABLE-LENGTH parameters for INIT */
+#define SCTP_IPV4_ADDRESS_TYPE	5
+#define SCTP_IPV4_ADDRESS_TYPE_LENGTH 8
+#define SCTP_IPV6_ADDRESS_TYPE	6
+#define SCTP_IPV6_ADDRESS_TYPE_LENGTH 20
+#define SCTP_STATE_COOKIE_TYPE		7
+#define SCTP_UNRECOGNIZED_TYPE	8
+#define SCTP_COOKIE_PRESERVATIVE_TYPE	9
+#define SCTP_COOKIE_PRESERVATIVE_TYPE_LENGTH	8
+#define SCTP_HOSTNAME_ADDRESS_TYPE 	11
+#define SCTP_SUPPORTED_ADDRESS_TYPES	12
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |        Type = 5               |      Length = 8               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                        IPv4 Address                           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  /*
+   * Contains an IPv4 address of the sending endpoint.
+   * It is binary encoded.
+   */
+  ip4_address_t address;
+
+} sctp_ipv4_addr_param_t;
+
+always_inline void
+vnet_sctp_set_ipv4_address (sctp_ipv4_addr_param_t * a, ip4_address_t address)
+{
+  a->param_hdr.type = clib_host_to_net_u16 (SCTP_IPV4_ADDRESS_TYPE);
+  a->param_hdr.length = clib_host_to_net_u16 (8);
+  a->address.as_u32 = clib_host_to_net_u32 (address.as_u32);
+}
+
+always_inline u32
+vnet_sctp_get_ipv4_address (sctp_ipv4_addr_param_t * a)
+{
+  return (clib_net_to_host_u32 (a->address.as_u32));
+}
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |            Type = 6           |          Length = 20          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                                                               |
+ * |                         IPv6 Address                          |
+ * |                                                               |
+ * |                                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  /*
+   * Contains an IPv6 address of the sending endpoint.
+   * It is binary encoded.
+   */
+  ip6_address_t address;
+
+} sctp_ipv6_addr_param_t;
+
+always_inline void
+vnet_sctp_set_ipv6_address (sctp_ipv6_addr_param_t * a, ip6_address_t address)
+{
+  a->param_hdr.type = clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE);
+  a->param_hdr.length = clib_host_to_net_u16 (20);
+  a->address.as_u64[0] = clib_host_to_net_u64 (address.as_u64[0]);
+  a->address.as_u64[1] = clib_host_to_net_u64 (address.as_u64[1]);
+}
+
+always_inline ip6_address_t
+vnet_sctp_get_ipv6_address (sctp_ipv6_addr_param_t * a)
+{
+  ip6_address_t ip6_address;
+
+  ip6_address.as_u64[0] = clib_net_to_host_u64 (a->address.as_u64[0]);
+  ip6_address.as_u64[1] = clib_net_to_host_u64 (a->address.as_u64[1]);
+
+  return ip6_address;
+}
+
+/*
+ * The sender of the INIT shall use this parameter to suggest to the
+ * receiver of the INIT for a longer life-span of the State Cookie.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Type = 9             |          Length = 8           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |         Suggested Cookie Life-Span Increment (msec.)          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  /*
+   * This parameter indicates to the receiver how much increment in
+   * milliseconds the sender wishes the receiver to add to its default
+   * cookie life-span.
+   *
+   * This optional parameter should be added to the INIT chunk by the
+   * sender when it reattempts establishing an association with a peer
+   * to which its previous attempt of establishing the association
+   * failed due to a stale cookie operation error. The receiver MAY
+   * choose to ignore the suggested cookie life-span increase for its
+   * own security reasons.
+   */
+  u32 life_span_inc;
+
+} sctp_cookie_preservative_param_t;
+
+always_inline void
+vnet_sctp_set_cookie_preservative (sctp_cookie_preservative_param_t * c,
+				   u32 life_span_inc)
+{
+  c->param_hdr.type = clib_host_to_net_u16 (SCTP_COOKIE_PRESERVATIVE_TYPE);
+  c->param_hdr.length = clib_host_to_net_u16 (8);
+  c->life_span_inc = clib_host_to_net_u32 (life_span_inc);
+}
+
+always_inline u32
+vnet_sctp_get_cookie_preservative (sctp_cookie_preservative_param_t * c)
+{
+  return (clib_net_to_host_u32 (c->life_span_inc));
+}
+
+#define FQDN_MAX_LENGTH 256
+
+/*
+ * The sender of INIT uses this parameter to pass its Host Name (in
+ * place of its IP addresses) to its peer.
+ * The peer is responsible for resolving the name.
+ * Using this parameter might make it more likely for the association to work
+ * across a NAT box.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Type = 11            |          Length               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                          Host Name                            /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+
+  /*
+   * This field contains a host name in "host name syntax" per RFC 1123
+   * Section 2.1
+   *
+   * Note: At least one null terminator is included in the Host Name
+   * string and must be included in the length.
+   */
+  char hostname[FQDN_MAX_LENGTH];
+
+} sctp_hostname_param_t;
+
+always_inline void
+vnet_sctp_set_hostname_address (sctp_hostname_param_t * h, char *hostname)
+{
+  h->param_hdr.length = FQDN_MAX_LENGTH;
+  h->param_hdr.type = clib_host_to_net_u16 (SCTP_HOSTNAME_ADDRESS_TYPE);
+  clib_memset (h->hostname, '0', FQDN_MAX_LENGTH);
+  memcpy (h->hostname, hostname, FQDN_MAX_LENGTH);
+}
+
+#define MAX_SUPPORTED_ADDRESS_TYPES	3
+
+/*
+ * The sender of INIT uses this parameter to list all the address types
+ * it can support.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Type = 12            |          Length               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |        Address Type #1        |        Address Type #2        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                            ......                             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  u16 address_type[MAX_SUPPORTED_ADDRESS_TYPES];
+
+} sctp_supported_addr_types_param_t;
+
+always_inline void
+vnet_sctp_set_supported_address_types (sctp_supported_addr_types_param_t * s)
+{
+  s->param_hdr.type = clib_host_to_net_u16 (SCTP_SUPPORTED_ADDRESS_TYPES);
+  s->param_hdr.length = 4 /* base = type + length */  +
+    MAX_SUPPORTED_ADDRESS_TYPES * 4;	/* each address type is 4 bytes */
+
+  s->address_type[0] = clib_host_to_net_u16 (SCTP_IPV4_ADDRESS_TYPE);
+  s->address_type[1] = clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE);
+  s->address_type[2] = clib_host_to_net_u16 (SCTP_HOSTNAME_ADDRESS_TYPE);
+}
+
+/*
+ * Error cause codes to be used for the sctp_error_cause.cause_code field
+ */
+#define INVALID_STREAM_IDENTIFIER	1
+#define MISSING_MANDATORY_PARAMETER	2
+#define STALE_COOKIE_ERROR		3
+#define OUT_OF_RESOURCE			4
+#define UNRESOLVABLE_ADDRESS		5
+#define UNRECOGNIZED_CHUNK_TYPE		6
+#define INVALID_MANDATORY_PARAMETER	7
+#define UNRECOGNIZED_PARAMETER		8
+#define NO_USER_DATA			9
+#define COOKIE_RECEIVED_WHILE_SHUTTING_DOWN	10
+#define RESTART_OF_ASSOCIATION_WITH_NEW_ADDR	11
+#define USER_INITIATED_ABORT		12
+#define PROTOCOL_VIOLATION		13
+
+always_inline void
+vnet_sctp_set_state_cookie (sctp_state_cookie_param_t * s)
+{
+  s->param_hdr.type = clib_host_to_net_u16 (SCTP_STATE_COOKIE_TYPE);
+
+  /* TODO: length & value to be populated */
+}
+
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  u32 value[];
+
+} sctp_unrecognized_param_t;
+
+always_inline void
+vnet_sctp_set_unrecognized_param (sctp_unrecognized_param_t * u)
+{
+  u->param_hdr.type = clib_host_to_net_u16 (UNRECOGNIZED_PARAMETER);
+
+  /* TODO: length & value to be populated */
+}
+
+/*
+ * Selective ACK (SACK) chunk
+ *
+ * This chunk is sent to the peer endpoint to acknowledge received DATA
+ * chunks and to inform the peer endpoint of gaps in the received
+ * subsequences of DATA chunks as represented by their TSNs.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 3    |Chunk  Flags   |      Chunk Length             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                      Cumulative TSN Ack                       |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Advertised Receiver Window Credit (a_rwnd)           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Number of Gap Ack Blocks = N  |  Number of Duplicate TSNs = X |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |  Gap Ack Block #1 Start       |   Gap Ack Block #1 End        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                                                               /
+ * \                              ...                              \
+ * /                                                               /
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Gap Ack Block #N Start      |  Gap Ack Block #N End         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                       Duplicate TSN 1                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                                                               /
+ * \                              ...                              \
+ * /                                                               /
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                       Duplicate TSN X                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  /*
+   * This parameter contains the TSN of the last DATA chunk received in
+   * sequence before a gap.  In the case where no DATA chunk has been
+   * received, this value is set to the peer's Initial TSN minus one.
+   */
+  u32 cumulative_tsn_ack;
+
+  /*
+   * This field indicates the updated receive buffer space in bytes of
+   * the sender of this SACK.
+   */
+  u32 a_rwnd;
+
+  /*
+   * Indicates the number of Gap Ack Blocks included in this SACK.
+   */
+  u16 gap_ack_blocks_count;
+
+  /*
+   * This field contains the number of duplicate TSNs the endpoint has
+   * received.  Each duplicate TSN is listed following the Gap Ack Block
+   * list.
+   */
+  u16 duplicate_tsn_count;
+
+  /*
+   * Indicates the Start offset TSN for this Gap Ack Block. To calculate
+   * the actual TSN number the Cumulative TSN Ack is added to this offset
+   * number. This calculated TSN identifies the first TSN in this Gap Ack
+   * Block that has been received.
+   */
+  u16 *gap_ack_block_start;
+
+  /*
+   * Indicates the End offset TSN for this Gap Ack Block. To calculate
+   * the actual TSN number, the Cumulative TSN Ack is added to this offset
+   * number. This calculated TSN identifies the TSN of the last DATA chunk
+   * received in this Gap Ack Block.
+   */
+  u16 *gap_ack_block_end;
+
+  /*
+   * Indicates the number of times a TSN was received in duplicate since
+   * the last SACK was sent. Every time a receiver gets a duplicate TSN
+   * (before sending the SACK), it adds it to the list of duplicates.
+   * The duplicate count is reinitialized to zero after sending each SACK.
+   */
+  u32 duplicate_tsn;
+
+} sctp_selective_ack_chunk_t;
+
+always_inline void
+vnet_sctp_set_cumulative_tsn_ack (sctp_selective_ack_chunk_t * s,
+				  u32 cumulative_tsn_ack)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SACK);
+  s->cumulative_tsn_ack = clib_host_to_net_u32 (cumulative_tsn_ack);
+}
+
+always_inline u32
+vnet_sctp_get_cumulative_tsn_ack (sctp_selective_ack_chunk_t * s)
+{
+  return clib_net_to_host_u32 (s->cumulative_tsn_ack);
+}
+
+always_inline void
+vnet_sctp_set_arwnd (sctp_selective_ack_chunk_t * s, u32 a_rwnd)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SACK);
+  s->a_rwnd = clib_host_to_net_u32 (a_rwnd);
+}
+
+always_inline u32
+vnet_sctp_get_arwnd (sctp_selective_ack_chunk_t * s)
+{
+  return clib_net_to_host_u32 (s->a_rwnd);
+}
+
+always_inline void
+vnet_sctp_set_gap_ack_blocks_count (sctp_selective_ack_chunk_t * s,
+				    u16 gap_ack_blocks_count)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SACK);
+  s->gap_ack_blocks_count = clib_host_to_net_u16 (gap_ack_blocks_count);
+
+  if (s->gap_ack_block_start == NULL)
+    s->gap_ack_block_start =
+      clib_mem_alloc (sizeof (u16) * gap_ack_blocks_count);
+  if (s->gap_ack_block_end == NULL)
+    s->gap_ack_block_end =
+      clib_mem_alloc (sizeof (u16) * gap_ack_blocks_count);
+}
+
+always_inline u16
+vnet_sctp_get_gap_ack_blocks_count (sctp_selective_ack_chunk_t * s)
+{
+  return clib_net_to_host_u32 (s->gap_ack_blocks_count);
+}
+
+always_inline void
+vnet_sctp_set_duplicate_tsn_count (sctp_selective_ack_chunk_t * s,
+				   u16 duplicate_tsn_count)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SACK);
+  s->duplicate_tsn_count = clib_host_to_net_u16 (duplicate_tsn_count);
+}
+
+always_inline u16
+vnet_sctp_get_duplicate_tsn_count (sctp_selective_ack_chunk_t * s)
+{
+  return clib_net_to_host_u16 (s->duplicate_tsn_count);
+}
+
+/*
+ * Heartbeat Info
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |    Heartbeat Info Type=1      |         HB Info Length        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                  Sender-Specific Heartbeat Info               /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  /*
+   * The Sender-Specific Heartbeat Info field should normally include
+   * information about the sender's current time when this HEARTBEAT
+   * chunk is sent and the destination transport address to which this
+   * HEARTBEAT is sent.
+   * This information is simply reflected back by the receiver in the
+   * HEARTBEAT ACK message.
+   *
+   * Note also that the HEARTBEAT message is both for reachability
+   * checking and for path verification.
+   * When a HEARTBEAT chunk is being used for path verification purposes,
+   * it MUST hold a 64-bit random nonce.
+   */
+  u64 hb_info;
+
+} sctp_hb_info_param_t;
+
+always_inline void
+vnet_sctp_set_heartbeat_info (sctp_hb_info_param_t * h, u64 hb_info,
+			      u16 hb_info_length)
+{
+  h->hb_info = clib_host_to_net_u16 (1);
+  h->param_hdr.length = clib_host_to_net_u16 (hb_info_length);
+  h->hb_info = clib_host_to_net_u64 (hb_info);
+}
+
+/*
+ * Heartbeat Request
+ *
+ * An endpoint should send this chunk to its peer endpoint to probe the
+ * reachability of a particular destination transport address defined in
+ * the present association.
+ * The parameter field contains the Heartbeat Information, which is a
+ * variable-length opaque data structure understood only by the sender.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 4    | Chunk  Flags  |      Heartbeat Length         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /            Heartbeat Information TLV (Variable-Length)        /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  sctp_hb_info_param_t hb_info;
+
+} sctp_hb_req_chunk_t;
+
+always_inline void
+vnet_sctp_set_hb_request_info (sctp_hb_req_chunk_t * h,
+			       sctp_hb_info_param_t * hb_info)
+{
+  vnet_sctp_set_chunk_type (&h->chunk_hdr, HEARTBEAT);
+  memcpy (&h->hb_info, hb_info, sizeof (h->hb_info));
+}
+
+/*
+ * Heartbeat Acknowledgement
+ *
+ * An endpoint should send this chunk to its peer endpoint as a response
+ * to a HEARTBEAT chunk.
+ * A HEARTBEAT ACK is always sent to the source IP address of the IP datagram
+ * containing the HEARTBEAT chunk to which this ack is responding.
+ */
+/*
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 5    | Chunk  Flags  |    Heartbeat Ack Length       |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /            Heartbeat Information TLV (Variable-Length)        /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef sctp_hb_req_chunk_t sctp_hb_ack_chunk_t;
+
+always_inline void
+vnet_sctp_set_hb_ack_info (sctp_hb_ack_chunk_t * h,
+			   sctp_hb_info_param_t * hb_info)
+{
+  vnet_sctp_set_chunk_type (&h->chunk_hdr, HEARTBEAT_ACK);
+  memcpy (&h->hb_info, hb_info, sizeof (h->hb_info));
+}
+
+/*
+ * Error cause
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |           Cause Code          |       Cause Length            |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                    Cause-Specific Information                 /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+*/
+typedef struct
+{
+
+  sctp_opt_params_hdr_t param_hdr;
+  u64 cause_info;
+
+} sctp_err_cause_param_t;
+
+
+/*
+ * An end-point sends this chunk to its peer end-point to notify it of
+ * certain error conditions.  It contains one or more error causes.
+ * An Operation Error is not considered fatal in and of itself, but may be
+ * used with an ABORT chunk to report a fatal condition.  It has the
+ * following parameters:
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 9    | Chunk  Flags  |           Length              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /                    one or more Error Causes                   /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  sctp_err_cause_param_t err_causes[];
+
+} sctp_operation_error_t;
+
+/*
+ * Abort Association (ABORT)
+ *
+ * The ABORT chunk is sent to the peer of an association to close the
+ * association.  The ABORT chunk may contain Cause Parameters to inform
+ * the receiver about the reason of the abort.  DATA chunks MUST NOT be
+ * bundled with ABORT.  Control chunks (except for INIT, INIT ACK, and
+ * SHUTDOWN COMPLETE) MAY be bundled with an ABORT, but they MUST be
+ * placed before the ABORT in the SCTP packet or they will be ignored by
+ * the receiver.
+ *
+ * If an endpoint receives an ABORT with a format error or no TCB is
+ * found, it MUST silently discard it.  Moreover, under any
+ * circumstances, an endpoint that receives an ABORT MUST NOT respond to
+ * that ABORT by sending an ABORT of its own.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 6    |Reserved     |T|           Length              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /                   zero or more Error Causes                   /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  sctp_err_cause_param_t err_causes[];
+
+} sctp_abort_chunk_t;
+
+always_inline void
+vnet_sctp_set_tbit (sctp_abort_chunk_t * a)
+{
+  vnet_sctp_set_chunk_type (&a->chunk_hdr, ABORT);
+  // a->chunk_hdr.flags = clib_host_to_net_u16 (1);
+}
+
+always_inline void
+vnet_sctp_unset_tbit (sctp_abort_chunk_t * a)
+{
+  vnet_sctp_set_chunk_type (&a->chunk_hdr, ABORT);
+  // a->chunk_hdr.flags = clib_host_to_net_u16 (0);
+}
+
+/*
+ * Shutdown Association (SHUTDOWN)
+ *
+ * An endpoint in an association MUST use this chunk to initiate a
+ * graceful close of the association with its peer.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 7    | Chunk  Flags  |      Length = 8               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                      Cumulative TSN Ack                       |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  /*
+   * This parameter contains the TSN of the last chunk received in
+   * sequence before any gaps.
+   *
+   * Note: Since the SHUTDOWN message does not contain Gap Ack Blocks,
+   * it cannot be used to acknowledge TSNs received out of order. In a
+   * SACK, lack of Gap Ack Blocks that were previously included
+   * indicates that the data receiver reneged on the associated DATA
+   * chunks. Since SHUTDOWN does not contain Gap Ack Blocks, the
+   * receiver of the SHUTDOWN shouldn't interpret the lack of a Gap Ack
+   * Block as a renege.
+   */
+  u32 cumulative_tsn_ack;
+
+} sctp_shutdown_association_chunk_t;
+
+always_inline void
+vnet_sctp_set_tsn_last_received_chunk (sctp_shutdown_association_chunk_t * s,
+				       u32 tsn_last_chunk)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SHUTDOWN);
+  s->cumulative_tsn_ack = clib_host_to_net_u32 (tsn_last_chunk);
+}
+
+/*
+ * Shutdown Acknowledgement (SHUTDOWN ACK)
+ *
+ * This chunk MUST be used to acknowledge the receipt of the SHUTDOWN
+ * chunk at the completion of the shutdown process.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 8    |Chunk  Flags   |      Length = 4               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+} sctp_shutdown_ack_chunk_t;
+
+always_inline void
+vnet_sctp_fill_shutdown_ack (sctp_shutdown_ack_chunk_t * s)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SHUTDOWN_ACK);
+  vnet_sctp_set_chunk_length (&s->chunk_hdr, 4);
+}
+
+#endif /* included_vnet_sctp_packet_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp_pg.c b/src/plugins/sctp/sctp_pg.c
new file mode 100644
index 00000000000..d253330143c
--- /dev/null
+++ b/src/plugins/sctp/sctp_pg.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <vnet/ip/ip.h>
+#include <vnet/pg/pg.h>
+
+uword
+unformat_pg_sctp_header (unformat_input_t * input, va_list * args)
+{
+  return 1;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/sctp/sctp_timer.h b/src/plugins/sctp/sctp_timer.h
new file mode 100644
index 00000000000..259dea92e09
--- /dev/null
+++ b/src/plugins/sctp/sctp_timer.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_sctp_timer_h__
+#define included_sctp_timer_h__
+
+#include <vppinfra/tw_timer_16t_2w_512sl.h>
+#include <vppinfra/tw_timer_16t_1w_2048sl.h>
+
+#endif /* included_sctp_timer_h__ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */