VPP-598: tcp stack initial commit

Change-Id: I49e5ce0aae6e4ff634024387ceaf7dbc432a0351
Signed-off-by: Dave Barach <dave@barachs.net>
Signed-off-by: Florin Coras <fcoras@cisco.com>

13 files changed, 4940 insertions, 0 deletions

diff --git a/src/vnet/session/application.c b/src/vnet/session/application.c
new file mode 100644
index 00000000000..a561e7d17f0
--- /dev/null
+++ b/src/vnet/session/application.c
@@ -0,0 +1,343 @@
+/*
+ * Copyright (c) 2017 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 <vnet/session/application.h>
+#include <vnet/session/session.h>
+
+/*
+ * Pool from which we allocate all applications
+ */
+static application_t *app_pool;
+
+/*
+ * Hash table of apps by api client index
+ */
+static uword *app_by_api_client_index;
+
+int
+application_api_queue_is_full (application_t * app)
+{
+  unix_shared_memory_queue_t *q;
+
+  /* builtin servers are always OK */
+  if (app->api_client_index == ~0)
+    return 0;
+
+  q = vl_api_client_index_to_input_queue (app->api_client_index);
+  if (!q)
+    return 1;
+
+  if (q->cursize == q->maxsize)
+    return 1;
+  return 0;
+}
+
+static void
+application_table_add (application_t * app)
+{
+  hash_set (app_by_api_client_index, app->api_client_index, app->index);
+}
+
+static void
+application_table_del (application_t * app)
+{
+  hash_unset (app_by_api_client_index, app->api_client_index);
+}
+
+application_t *
+application_lookup (u32 api_client_index)
+{
+  uword *p;
+  p = hash_get (app_by_api_client_index, api_client_index);
+  if (p)
+    return application_get (p[0]);
+
+  return 0;
+}
+
+void
+application_del (application_t * app)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  api_main_t *am = &api_main;
+  void *oldheap;
+  session_manager_t *sm;
+
+  if (app->mode == APP_SERVER)
+    {
+      sm = session_manager_get (app->session_manager_index);
+      session_manager_del (smm, sm);
+    }
+
+  /* Free the event fifo in the /vpe-api shared-memory segment */
+  oldheap = svm_push_data_heap (am->vlib_rp);
+  if (app->event_queue)
+    unix_shared_memory_queue_free (app->event_queue);
+  svm_pop_heap (oldheap);
+
+  application_table_del (app);
+
+  pool_put (app_pool, app);
+}
+
+application_t *
+application_new (application_type_t type, session_type_t sst,
+		 u32 api_client_index, u32 flags, session_cb_vft_t * cb_fns)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  api_main_t *am = &api_main;
+  application_t *app;
+  void *oldheap;
+  session_manager_t *sm;
+
+  pool_get (app_pool, app);
+  memset (app, 0, sizeof (*app));
+
+  /* Allocate event fifo in the /vpe-api shared-memory segment */
+  oldheap = svm_push_data_heap (am->vlib_rp);
+
+  /* Allocate server event queue */
+  app->event_queue =
+    unix_shared_memory_queue_init (128 /* nels $$$$ config */ ,
+				   sizeof (session_fifo_event_t),
+				   0 /* consumer pid */ ,
+				   0
+				   /* (do not) signal when queue non-empty */
+    );
+
+  svm_pop_heap (oldheap);
+
+  /* If a server, allocate session manager */
+  if (type == APP_SERVER)
+    {
+      pool_get (smm->session_managers, sm);
+      memset (sm, 0, sizeof (*sm));
+
+      app->session_manager_index = sm - smm->session_managers;
+    }
+  else if (type == APP_CLIENT)
+    {
+      /* Allocate connect session manager if needed */
+      if (smm->connect_manager_index[sst] == INVALID_INDEX)
+	connects_session_manager_init (smm, sst);
+      app->session_manager_index = smm->connect_manager_index[sst];
+    }
+
+  app->mode = type;
+  app->index = application_get_index (app);
+  app->session_type = sst;
+  app->api_client_index = api_client_index;
+  app->flags = flags;
+  app->cb_fns = *cb_fns;
+
+  /* Add app to lookup by api_client_index table */
+  application_table_add (app);
+
+  return app;
+}
+
+application_t *
+application_get (u32 index)
+{
+  return pool_elt_at_index (app_pool, index);
+}
+
+u32
+application_get_index (application_t * app)
+{
+  return app - app_pool;
+}
+
+int
+application_server_init (application_t * server, u32 segment_size,
+			 u32 add_segment_size, u32 rx_fifo_size,
+			 u32 tx_fifo_size, u8 ** segment_name)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  session_manager_t *sm;
+  int rv;
+
+  sm = session_manager_get (server->session_manager_index);
+
+  /* Add first segment */
+  if ((rv = session_manager_add_first_segment (smm, sm, segment_size,
+					       segment_name)))
+    {
+      return rv;
+    }
+
+  /* Setup session manager */
+  sm->add_segment_size = add_segment_size;
+  sm->rx_fifo_size = rx_fifo_size;
+  sm->tx_fifo_size = tx_fifo_size;
+  sm->add_segment = sm->add_segment_size != 0;
+  return 0;
+}
+
+u8 *
+format_application_server (u8 * s, va_list * args)
+{
+  application_t *srv = va_arg (*args, application_t *);
+  int verbose = va_arg (*args, int);
+  vl_api_registration_t *regp;
+  stream_session_t *listener;
+  u8 *server_name, *str, *seg_name;
+  u32 segment_size;
+
+  if (srv == 0)
+    {
+      if (verbose)
+	s = format (s, "%-40s%-20s%-15s%-15s%-10s", "Connection", "Server",
+		    "Segment", "API Client", "Cookie");
+      else
+	s = format (s, "%-40s%-20s", "Connection", "Server");
+
+      return s;
+    }
+
+  regp = vl_api_client_index_to_registration (srv->api_client_index);
+  if (!regp)
+    server_name = format (0, "%s%c", regp->name, 0);
+  else
+    server_name = regp->name;
+
+  listener = stream_session_listener_get (srv->session_type,
+					  srv->session_index);
+  str = format (0, "%U", format_stream_session, listener, verbose);
+
+  session_manager_get_segment_info (listener->server_segment_index, &seg_name,
+				    &segment_size);
+  if (verbose)
+    {
+      s = format (s, "%-40s%-20s%-20s%-10d%-10d", str, server_name,
+		  seg_name, srv->api_client_index, srv->accept_cookie);
+    }
+  else
+    s = format (s, "%-40s%-20s", str, server_name);
+  return s;
+}
+
+u8 *
+format_application_client (u8 * s, va_list * args)
+{
+  application_t *client = va_arg (*args, application_t *);
+  int verbose = va_arg (*args, int);
+  stream_session_t *session;
+  u8 *str, *seg_name;
+  u32 segment_size;
+
+  if (client == 0)
+    {
+      if (verbose)
+	s =
+	  format (s, "%-40s%-20s%-10s", "Connection", "Segment",
+		  "API Client");
+      else
+	s = format (s, "%-40s", "Connection");
+
+      return s;
+    }
+
+  session = stream_session_get (client->session_index, client->thread_index);
+  str = format (0, "%U", format_stream_session, session, verbose);
+
+  session_manager_get_segment_info (session->server_segment_index, &seg_name,
+				    &segment_size);
+  if (verbose)
+    {
+      s = format (s, "%-40s%-20s%-10d%", str, seg_name,
+		  client->api_client_index);
+    }
+  else
+    s = format (s, "%-40s", str);
+  return s;
+}
+
+static clib_error_t *
+show_app_command_fn (vlib_main_t * vm, unformat_input_t * input,
+		     vlib_cli_command_t * cmd)
+{
+  application_t *app;
+  int do_server = 0;
+  int do_client = 0;
+  int verbose = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "server"))
+	do_server = 1;
+      else if (unformat (input, "client"))
+	do_client = 1;
+      else if (unformat (input, "verbose"))
+	verbose = 1;
+      else
+	break;
+    }
+
+  if (do_server)
+    {
+      if (pool_elts (app_pool))
+	{
+	  vlib_cli_output (vm, "%U", format_application_server,
+			   0 /* header */ ,
+			   verbose);
+          /* *INDENT-OFF* */
+          pool_foreach (app, app_pool,
+          ({
+            if (app->mode == APP_SERVER)
+              vlib_cli_output (vm, "%U", format_application_server, app,
+                               verbose);
+          }));
+          /* *INDENT-ON* */
+	}
+      else
+	vlib_cli_output (vm, "No active server bindings");
+    }
+
+  if (do_client)
+    {
+      if (pool_elts (app_pool))
+	{
+	  vlib_cli_output (vm, "%U", format_application_client,
+			   0 /* header */ ,
+			   verbose);
+          /* *INDENT-OFF* */
+          pool_foreach (app, app_pool,
+          ({
+            if (app->mode == APP_CLIENT)
+              vlib_cli_output (vm, "%U", format_application_client, app,
+                               verbose);
+          }));
+          /* *INDENT-ON* */
+	}
+      else
+	vlib_cli_output (vm, "No active server bindings");
+    }
+
+  return 0;
+}
+
+VLIB_CLI_COMMAND (show_app_command, static) =
+{
+.path = "show app",.short_help =
+    "show app [server|client] [verbose]",.function = show_app_command_fn,};
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/application.h b/src/vnet/session/application.h
new file mode 100644
index 00000000000..027d6967fd7
--- /dev/null
+++ b/src/vnet/session/application.h
@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2017 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 SRC_VNET_SESSION_APPLICATION_H_
+#define SRC_VNET_SESSION_APPLICATION_H_
+
+#include <vnet/vnet.h>
+#include <vnet/session/session.h>
+
+typedef enum
+{
+  APP_SERVER,
+  APP_CLIENT
+} application_type_t;
+
+typedef struct _stream_session_cb_vft
+{
+  /** Notify server of new segment */
+  int (*add_segment_callback) (u32 api_client_index, const u8 * seg_name,
+			       u32 seg_size);
+
+  /** Notify server of newly accepted session */
+  int (*session_accept_callback) (stream_session_t * new_session);
+
+  /* Connection request callback */
+  int (*session_connected_callback) (u32 api_client_index,
+				     stream_session_t * s, u8 code);
+
+  /** Notify app that session is closing */
+  void (*session_disconnect_callback) (stream_session_t * s);
+
+  /** Notify app that session was reset */
+  void (*session_reset_callback) (stream_session_t * s);
+
+  /* Direct RX callback, for built-in servers */
+  int (*builtin_server_rx_callback) (stream_session_t * session);
+
+  /* Redirect connection to local server */
+  int (*redirect_connect_callback) (u32 api_client_index, void *mp);
+} session_cb_vft_t;
+
+typedef struct _application
+{
+  /** Index in server pool */
+  u32 index;
+
+  /** Flags */
+  u32 flags;
+
+  /** Binary API connection index, ~0 if internal */
+  u32 api_client_index;
+
+  /* */
+  u32 api_context;
+
+  /** Application listens for events on this svm queue */
+  unix_shared_memory_queue_t *event_queue;
+
+  /** Stream session type */
+  u8 session_type;
+
+  /* Stream server mode: accept or connect */
+  u8 mode;
+
+  u32 session_manager_index;
+
+  /*
+   * Bind/Listen specific
+   */
+
+  /** Accept cookie, for multiple session flavors ($$$ maybe) */
+  u32 accept_cookie;
+
+  /** Index of the listen session or connect session */
+  u32 session_index;
+
+  /** Session thread index for client connect sessions */
+  u32 thread_index;
+
+  /*
+   * Callbacks: shoulder-taps for the server/client
+   */
+  session_cb_vft_t cb_fns;
+} application_t;
+
+application_t *application_new (application_type_t type, session_type_t sst,
+				u32 api_client_index, u32 flags,
+				session_cb_vft_t * cb_fns);
+void application_del (application_t * app);
+application_t *application_get (u32 index);
+application_t *application_lookup (u32 api_client_index);
+u32 application_get_index (application_t * app);
+
+int
+application_server_init (application_t * server, u32 segment_size,
+			 u32 add_segment_size, u32 rx_fifo_size,
+			 u32 tx_fifo_size, u8 ** segment_name);
+int application_api_queue_is_full (application_t * app);
+
+#endif /* SRC_VNET_SESSION_APPLICATION_H_ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/application_interface.c b/src/vnet/session/application_interface.c
new file mode 100644
index 00000000000..0ea77fd8c4e
--- /dev/null
+++ b/src/vnet/session/application_interface.c
@@ -0,0 +1,459 @@
+/*
+ * Copyright (c) 2016 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 <vnet/session/application_interface.h>
+
+#include <vnet/session/session.h>
+#include <vlibmemory/api.h>
+#include <vnet/dpo/load_balance.h>
+#include <vnet/fib/ip4_fib.h>
+
+/** @file
+    VPP's application/session API bind/unbind/connect/disconnect calls
+*/
+
+static u8
+ip_is_zero (ip46_address_t * ip46_address, u8 is_ip4)
+{
+  if (is_ip4)
+    return (ip46_address->ip4.as_u32 == 0);
+  else
+    return (ip46_address->as_u64[0] == 0 && ip46_address->as_u64[1] == 0);
+}
+
+static u8
+ip_is_local (ip46_address_t * ip46_address, u8 is_ip4)
+{
+  fib_node_index_t fei;
+  fib_entry_flag_t flags;
+  fib_prefix_t prefix;
+
+  /* Check if requester is local */
+  if (is_ip4)
+    {
+      prefix.fp_len = 32;
+      prefix.fp_proto = FIB_PROTOCOL_IP4;
+    }
+  else
+    {
+      prefix.fp_len = 128;
+      prefix.fp_proto = FIB_PROTOCOL_IP6;
+    }
+
+  clib_memcpy (&prefix.fp_addr, ip46_address, sizeof (ip46_address));
+  fei = fib_table_lookup (0, &prefix);
+  flags = fib_entry_get_flags (fei);
+
+  return (flags & FIB_ENTRY_FLAG_LOCAL);
+}
+
+int
+api_parse_session_handle (u64 handle, u32 * session_index, u32 * thread_index)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  stream_session_t *pool;
+
+  *thread_index = handle & 0xFFFFFFFF;
+  *session_index = handle >> 32;
+
+  if (*thread_index >= vec_len (smm->sessions))
+    return VNET_API_ERROR_INVALID_VALUE;
+
+  pool = smm->sessions[*thread_index];
+
+  if (pool_is_free_index (pool, *session_index))
+    return VNET_API_ERROR_INVALID_VALUE_2;
+
+  return 0;
+}
+
+int
+vnet_bind_i (u32 api_client_index, ip46_address_t * ip46, u16 port_host_order,
+	     session_type_t sst, u64 * options, session_cb_vft_t * cb_fns,
+	     application_t ** app, u32 * len_seg_name, char *seg_name)
+{
+  u8 *segment_name = 0;
+  application_t *server = 0;
+  stream_session_t *listener;
+  u8 is_ip4;
+
+  listener =
+    stream_session_lookup_listener (ip46,
+				    clib_host_to_net_u16 (port_host_order),
+				    sst);
+
+  if (listener)
+    return VNET_API_ERROR_ADDRESS_IN_USE;
+
+  if (application_lookup (api_client_index))
+    {
+      clib_warning ("Only one bind supported for now");
+      return VNET_API_ERROR_ADDRESS_IN_USE;
+    }
+
+  is_ip4 = SESSION_TYPE_IP4_UDP == sst || SESSION_TYPE_IP4_TCP == sst;
+  if (!ip_is_zero (ip46, is_ip4) && !ip_is_local (ip46, is_ip4))
+    return VNET_API_ERROR_INVALID_VALUE;
+
+  /* Allocate and initialize stream server */
+  server = application_new (APP_SERVER, sst, api_client_index,
+			    options[SESSION_OPTIONS_FLAGS], cb_fns);
+
+  application_server_init (server, options[SESSION_OPTIONS_SEGMENT_SIZE],
+			   options[SESSION_OPTIONS_ADD_SEGMENT_SIZE],
+			   options[SESSION_OPTIONS_RX_FIFO_SIZE],
+			   options[SESSION_OPTIONS_TX_FIFO_SIZE],
+			   &segment_name);
+
+  /* Setup listen path down to transport */
+  stream_session_start_listen (server->index, ip46, port_host_order);
+
+  /*
+   * Return values
+   */
+
+  ASSERT (vec_len (segment_name) <= 128);
+  *len_seg_name = vec_len (segment_name);
+  memcpy (seg_name, segment_name, *len_seg_name);
+  *app = server;
+
+  return 0;
+}
+
+int
+vnet_unbind_i (u32 api_client_index)
+{
+  application_t *server;
+
+  /*
+   * Find the stream_server_t corresponding to the api client
+   */
+  server = application_lookup (api_client_index);
+  if (!server)
+    return VNET_API_ERROR_INVALID_VALUE_2;
+
+  /* Clear the listener */
+  stream_session_stop_listen (server->index);
+  application_del (server);
+
+  return 0;
+}
+
+int
+vnet_connect_i (u32 api_client_index, u32 api_context, session_type_t sst,
+		ip46_address_t * ip46, u16 port, u64 * options, void *mp,
+		session_cb_vft_t * cb_fns)
+{
+  stream_session_t *listener;
+  application_t *server, *app;
+
+  /*
+   * Figure out if connecting to a local server
+   */
+  listener = stream_session_lookup_listener (ip46,
+					     clib_host_to_net_u16 (port),
+					     sst);
+  if (listener)
+    {
+      server = application_get (listener->app_index);
+
+      /*
+       * Server is willing to have a direct fifo connection created
+       * instead of going through the state machine, etc.
+       */
+      if (server->flags & SESSION_OPTIONS_FLAGS_USE_FIFO)
+	return server->cb_fns.
+	  redirect_connect_callback (server->api_client_index, mp);
+    }
+
+  /* Create client app */
+  app = application_new (APP_CLIENT, sst, api_client_index,
+			 options[SESSION_OPTIONS_FLAGS], cb_fns);
+
+  app->api_context = api_context;
+
+  /*
+   * Not connecting to a local server. Create regular session
+   */
+  stream_session_open (sst, ip46, port, app->index);
+
+  return 0;
+}
+
+/**
+ * unformat a vnet URI
+ *
+ * fifo://name
+ * tcp://ip46-addr:port
+ * udp://ip46-addr:port
+ *
+ * u8 ip46_address[16];
+ * u16  port_in_host_byte_order;
+ * stream_session_type_t sst;
+ * u8 *fifo_name;
+ *
+ * if (unformat (input, "%U", unformat_vnet_uri, &ip46_address,
+ *              &sst, &port, &fifo_name))
+ *  etc...
+ *
+ */
+uword
+unformat_vnet_uri (unformat_input_t * input, va_list * args)
+{
+  ip46_address_t *address = va_arg (*args, ip46_address_t *);
+  session_type_t *sst = va_arg (*args, session_type_t *);
+  u16 *port = va_arg (*args, u16 *);
+
+  if (unformat (input, "tcp://%U/%d", unformat_ip4_address, &address->ip4,
+		port))
+    {
+      *sst = SESSION_TYPE_IP4_TCP;
+      return 1;
+    }
+  if (unformat (input, "udp://%U/%d", unformat_ip4_address, &address->ip4,
+		port))
+    {
+      *sst = SESSION_TYPE_IP4_UDP;
+      return 1;
+    }
+  if (unformat (input, "udp://%U/%d", unformat_ip6_address, &address->ip6,
+		port))
+    {
+      *sst = SESSION_TYPE_IP6_UDP;
+      return 1;
+    }
+  if (unformat (input, "tcp://%U/%d", unformat_ip6_address, &address->ip6,
+		port))
+    {
+      *sst = SESSION_TYPE_IP6_TCP;
+      return 1;
+    }
+
+  return 0;
+}
+
+int
+parse_uri (char *uri, session_type_t * sst, ip46_address_t * addr,
+	   u16 * port_number_host_byte_order)
+{
+  unformat_input_t _input, *input = &_input;
+
+  /* Make sure */
+  uri = (char *) format (0, "%s%c", uri, 0);
+
+  /* Parse uri */
+  unformat_init_string (input, uri, strlen (uri));
+  if (!unformat (input, "%U", unformat_vnet_uri, addr, sst,
+		 port_number_host_byte_order))
+    {
+      unformat_free (input);
+      return VNET_API_ERROR_INVALID_VALUE;
+    }
+  unformat_free (input);
+
+  return 0;
+}
+
+int
+vnet_bind_uri (vnet_bind_args_t * a)
+{
+  application_t *server = 0;
+  u16 port_host_order;
+  session_type_t sst = SESSION_N_TYPES;
+  ip46_address_t ip46;
+  int rv;
+
+  memset (&ip46, 0, sizeof (ip46));
+  rv = parse_uri (a->uri, &sst, &ip46, &port_host_order);
+  if (rv)
+    return rv;
+
+  if ((rv = vnet_bind_i (a->api_client_index, &ip46, port_host_order, sst,
+			 a->options, a->session_cb_vft, &server,
+			 &a->segment_name_length, a->segment_name)))
+    return rv;
+
+  a->server_event_queue_address = (u64) server->event_queue;
+  return 0;
+}
+
+session_type_t
+session_type_from_proto_and_ip (session_api_proto_t proto, u8 is_ip4)
+{
+  if (proto == SESSION_PROTO_TCP)
+    {
+      if (is_ip4)
+	return SESSION_TYPE_IP4_TCP;
+      else
+	return SESSION_TYPE_IP6_TCP;
+    }
+  else
+    {
+      if (is_ip4)
+	return SESSION_TYPE_IP4_UDP;
+      else
+	return SESSION_TYPE_IP6_UDP;
+    }
+
+  return SESSION_N_TYPES;
+}
+
+int
+vnet_unbind_uri (char *uri, u32 api_client_index)
+{
+  u16 port_number_host_byte_order;
+  session_type_t sst = SESSION_N_TYPES;
+  ip46_address_t ip46_address;
+  stream_session_t *listener;
+  int rv;
+
+  rv = parse_uri (uri, &sst, &ip46_address, &port_number_host_byte_order);
+  if (rv)
+    return rv;
+
+  listener =
+    stream_session_lookup_listener (&ip46_address,
+				    clib_host_to_net_u16
+				    (port_number_host_byte_order), sst);
+
+  if (!listener)
+    return VNET_API_ERROR_ADDRESS_NOT_IN_USE;
+
+  /* External client? */
+  if (api_client_index != ~0)
+    {
+      ASSERT (vl_api_client_index_to_registration (api_client_index));
+    }
+
+  return vnet_unbind_i (api_client_index);
+}
+
+int
+vnet_connect_uri (vnet_connect_args_t * a)
+{
+  ip46_address_t ip46_address;
+  u16 port;
+  session_type_t sst;
+  application_t *app;
+  int rv;
+
+  app = application_lookup (a->api_client_index);
+  if (app)
+    {
+      clib_warning ("Already have a connect from this app");
+      return VNET_API_ERROR_INVALID_VALUE_2;
+    }
+
+  /* Parse uri */
+  rv = parse_uri (a->uri, &sst, &ip46_address, &port);
+  if (rv)
+    return rv;
+
+  return vnet_connect_i (a->api_client_index, a->api_context, sst,
+			 &ip46_address, port, a->options, a->mp,
+			 a->session_cb_vft);
+}
+
+int
+vnet_disconnect_session (u32 client_index, u32 session_index,
+			 u32 thread_index)
+{
+  stream_session_t *session;
+
+  session = stream_session_get (session_index, thread_index);
+  stream_session_disconnect (session);
+
+  return 0;
+}
+
+
+int
+vnet_bind (vnet_bind_args_t * a)
+{
+  application_t *server = 0;
+  session_type_t sst = SESSION_N_TYPES;
+  int rv;
+
+  sst = session_type_from_proto_and_ip (a->proto, a->tep.is_ip4);
+  if ((rv = vnet_bind_i (a->api_client_index, &a->tep.ip, a->tep.port, sst,
+			 a->options, a->session_cb_vft, &server,
+			 &a->segment_name_length, a->segment_name)))
+    return rv;
+
+  a->server_event_queue_address = (u64) server->event_queue;
+  a->handle = (u64) a->tep.vrf << 32 | (u64) server->session_index;
+  return 0;
+}
+
+int
+vnet_unbind (vnet_unbind_args_t * a)
+{
+  application_t *server;
+
+  if (a->api_client_index != ~0)
+    {
+      ASSERT (vl_api_client_index_to_registration (a->api_client_index));
+    }
+
+  /* Make sure this is the right one */
+  server = application_lookup (a->api_client_index);
+  ASSERT (server->session_index == (0xFFFFFFFF & a->handle));
+
+  /* TODO use handle to disambiguate namespaces/vrfs */
+  return vnet_unbind_i (a->api_client_index);
+}
+
+int
+vnet_connect (vnet_connect_args_t * a)
+{
+  session_type_t sst;
+  application_t *app;
+
+  app = application_lookup (a->api_client_index);
+  if (app)
+    {
+      clib_warning ("Already have a connect from this app");
+      return VNET_API_ERROR_INVALID_VALUE_2;
+    }
+
+  sst = session_type_from_proto_and_ip (a->proto, a->tep.is_ip4);
+  return vnet_connect_i (a->api_client_index, a->api_context, sst, &a->tep.ip,
+			 a->tep.port, a->options, a->mp, a->session_cb_vft);
+}
+
+int
+vnet_disconnect (vnet_disconnect_args_t * a)
+{
+  stream_session_t *session;
+  u32 session_index, thread_index;
+
+  if (api_parse_session_handle (a->handle, &session_index, &thread_index))
+    {
+      clib_warning ("Invalid handle");
+      return -1;
+    }
+
+  session = stream_session_get (session_index, thread_index);
+  stream_session_disconnect (session);
+
+  return 0;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
new file mode 100644
index 00000000000..8d87c067841
--- /dev/null
+++ b/src/vnet/session/application_interface.h
@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2016 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_uri_h__
+#define __included_uri_h__
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <svm/svm_fifo_segment.h>
+#include <vnet/session/session.h>
+#include <vnet/session/application.h>
+#include <vnet/session/transport.h>
+
+typedef enum _session_api_proto
+{
+  SESSION_PROTO_TCP,
+  SESSION_PROTO_UDP
+} session_api_proto_t;
+
+typedef struct _vnet_bind_args_t
+{
+  union
+  {
+    char *uri;
+    struct
+    {
+      transport_endpoint_t tep;
+      session_api_proto_t proto;
+    };
+  };
+
+  u32 api_client_index;
+  u64 *options;
+  session_cb_vft_t *session_cb_vft;
+
+  /*
+   * Results
+   */
+  char *segment_name;
+  u32 segment_name_length;
+  u64 server_event_queue_address;
+  u64 handle;
+} vnet_bind_args_t;
+
+typedef struct _vnet_unbind_args_t
+{
+  union
+  {
+    char *uri;
+    u64 handle;
+  };
+  u32 api_client_index;
+} vnet_unbind_args_t;
+
+typedef struct _vnet_connect_args
+{
+  union
+  {
+    char *uri;
+    struct
+    {
+      transport_endpoint_t tep;
+      session_api_proto_t proto;
+    };
+  };
+  u32 api_client_index;
+  u32 api_context;
+  u64 *options;
+  session_cb_vft_t *session_cb_vft;
+
+  /* Used for redirects */
+  void *mp;
+} vnet_connect_args_t;
+
+typedef struct _vnet_disconnect_args_t
+{
+  u64 handle;
+  u32 api_client_index;
+} vnet_disconnect_args_t;
+
+/* Bind / connect options */
+typedef enum
+{
+  SESSION_OPTIONS_FLAGS,
+  SESSION_OPTIONS_SEGMENT_SIZE,
+  SESSION_OPTIONS_ADD_SEGMENT_SIZE,
+  SESSION_OPTIONS_RX_FIFO_SIZE,
+  SESSION_OPTIONS_TX_FIFO_SIZE,
+  SESSION_OPTIONS_ACCEPT_COOKIE,
+  SESSION_OPTIONS_N_OPTIONS
+} session_options_index_t;
+
+/** Server can handle delegated connect requests from local clients */
+#define SESSION_OPTIONS_FLAGS_USE_FIFO	(1<<0)
+
+/** Server wants vpp to add segments when out of memory for fifos */
+#define SESSION_OPTIONS_FLAGS_ADD_SEGMENT   (1<<1)
+
+#define VNET_CONNECT_REDIRECTED	123
+
+int vnet_bind_uri (vnet_bind_args_t *);
+int vnet_unbind_uri (char *uri, u32 api_client_index);
+int vnet_connect_uri (vnet_connect_args_t * a);
+int
+vnet_disconnect_session (u32 client_index, u32 session_index,
+			 u32 thread_index);
+
+int vnet_bind (vnet_bind_args_t * a);
+int vnet_connect (vnet_connect_args_t * a);
+int vnet_unbind (vnet_unbind_args_t * a);
+int vnet_disconnect (vnet_disconnect_args_t * a);
+
+int
+api_parse_session_handle (u64 handle, u32 * session_index,
+			  u32 * thread_index);
+
+#endif /* __included_uri_h__ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/hashes.c b/src/vnet/session/hashes.c
new file mode 100644
index 00000000000..1808dd73f90
--- /dev/null
+++ b/src/vnet/session/hashes.c
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2016 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.
+ */
+
+/** Generate typed init functions for multiple hash table styles... */
+
+#include <vppinfra/bihash_16_8.h>
+#include <vppinfra/bihash_template.h>
+
+#include <vppinfra/bihash_template.c>
+
+#undef __included_bihash_template_h__
+
+#include <vppinfra/bihash_48_8.h>
+#include <vppinfra/bihash_template.h>
+
+#include <vppinfra/bihash_template.c>
diff --git a/src/vnet/session/node.c b/src/vnet/session/node.c
new file mode 100644
index 00000000000..e467f4e99e2
--- /dev/null
+++ b/src/vnet/session/node.c
@@ -0,0 +1,435 @@
+/*
+ * Copyright (c) 2017 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 <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vnet/ip/ip.h>
+
+#include <vnet/tcp/tcp.h>
+
+#include <vppinfra/hash.h>
+#include <vppinfra/error.h>
+#include <vppinfra/elog.h>
+#include <vlibmemory/unix_shared_memory_queue.h>
+
+#include <vnet/udp/udp_packet.h>
+#include <vnet/lisp-cp/packets.h>
+#include <math.h>
+
+vlib_node_registration_t session_queue_node;
+
+typedef struct
+{
+  u32 session_index;
+  u32 server_thread_index;
+} session_queue_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_session_queue_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 *);
+  session_queue_trace_t *t = va_arg (*args, session_queue_trace_t *);
+
+  s = format (s, "SESSION_QUEUE: session index %d, server thread index %d",
+	      t->session_index, t->server_thread_index);
+  return s;
+}
+
+vlib_node_registration_t session_queue_node;
+
+#define foreach_session_queue_error                 \
+_(TX, "Packets transmitted")                    \
+_(TIMER, "Timer events")
+
+typedef enum
+{
+#define _(sym,str) SESSION_QUEUE_ERROR_##sym,
+  foreach_session_queue_error
+#undef _
+    SESSION_QUEUE_N_ERROR,
+} session_queue_error_t;
+
+static char *session_queue_error_strings[] = {
+#define _(sym,string) string,
+  foreach_session_queue_error
+#undef _
+};
+
+static u32 session_type_to_next[] = {
+  SESSION_QUEUE_NEXT_TCP_IP4_OUTPUT,
+  SESSION_QUEUE_NEXT_IP4_LOOKUP,
+  SESSION_QUEUE_NEXT_TCP_IP6_OUTPUT,
+  SESSION_QUEUE_NEXT_IP6_LOOKUP,
+};
+
+always_inline int
+session_fifo_rx_i (vlib_main_t * vm, vlib_node_runtime_t * node,
+		   session_manager_main_t * smm, session_fifo_event_t * e0,
+		   stream_session_t * s0, u32 thread_index, int *n_tx_packets,
+		   u8 peek_data)
+{
+  u32 n_trace = vlib_get_trace_count (vm, node);
+  u32 left_to_snd0, max_len_to_snd0, len_to_deq0, n_bufs, snd_space0;
+  u32 n_frame_bytes, n_frames_per_evt;
+  transport_connection_t *tc0;
+  transport_proto_vft_t *transport_vft;
+  u32 next_index, next0, *to_next, n_left_to_next, bi0;
+  vlib_buffer_t *b0;
+  u32 rx_offset;
+  u16 snd_mss0;
+  u8 *data0;
+  int i;
+
+  next_index = next0 = session_type_to_next[s0->session_type];
+
+  transport_vft = session_get_transport_vft (s0->session_type);
+  tc0 = transport_vft->get_connection (s0->connection_index, thread_index);
+
+  /* Make sure we have space to send and there's something to dequeue */
+  snd_space0 = transport_vft->send_space (tc0);
+  snd_mss0 = transport_vft->send_mss (tc0);
+
+  if (snd_space0 == 0 || svm_fifo_max_dequeue (s0->server_tx_fifo) == 0
+      || snd_mss0 == 0)
+    return 0;
+
+  ASSERT (e0->enqueue_length > 0);
+
+  /* Ensure we're not writing more than transport window allows */
+  max_len_to_snd0 = clib_min (e0->enqueue_length, snd_space0);
+
+  if (peek_data)
+    {
+      /* Offset in rx fifo from where to peek data  */
+      rx_offset = transport_vft->rx_fifo_offset (tc0);
+    }
+
+  /* TODO check if transport is willing to send len_to_snd0
+   * bytes (Nagle) */
+
+  n_frame_bytes = snd_mss0 * VLIB_FRAME_SIZE;
+  n_frames_per_evt = ceil ((double) max_len_to_snd0 / n_frame_bytes);
+
+  n_bufs = vec_len (smm->tx_buffers[thread_index]);
+  left_to_snd0 = max_len_to_snd0;
+  for (i = 0; i < n_frames_per_evt; i++)
+    {
+      /* Make sure we have at least one full frame of buffers ready */
+      if (PREDICT_FALSE (n_bufs < VLIB_FRAME_SIZE))
+	{
+	  vec_validate (smm->tx_buffers[thread_index],
+			n_bufs + VLIB_FRAME_SIZE - 1);
+	  n_bufs +=
+	    vlib_buffer_alloc (vm, &smm->tx_buffers[thread_index][n_bufs],
+			       VLIB_FRAME_SIZE);
+
+	  /* buffer shortage
+	   * XXX 0.9 because when debugging we might not get a full frame */
+	  if (PREDICT_FALSE (n_bufs < 0.9 * VLIB_FRAME_SIZE))
+	    {
+	      /* Keep track of how much we've dequeued and exit */
+	      e0->enqueue_length -= max_len_to_snd0 - left_to_snd0;
+	      return -1;
+	    }
+
+	  _vec_len (smm->tx_buffers[thread_index]) = n_bufs;
+	}
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+      while (left_to_snd0 && n_left_to_next)
+	{
+	  /* Get free buffer */
+	  n_bufs--;
+	  bi0 = smm->tx_buffers[thread_index][n_bufs];
+	  _vec_len (smm->tx_buffers[thread_index]) = n_bufs;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b0->error = 0;
+	  b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID
+	    | VNET_BUFFER_LOCALLY_ORIGINATED;
+	  b0->current_data = 0;
+
+	  /* RX on the local interface. tx in default fib */
+	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
+	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+
+	  /* usual speculation, or the enqueue_x1 macro will barf */
+	  to_next[0] = bi0;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);
+	  if (PREDICT_FALSE (n_trace > 0))
+	    {
+	      session_queue_trace_t *t0;
+	      vlib_trace_buffer (vm, node, next_index, b0,
+				 1 /* follow_chain */ );
+	      vlib_set_trace_count (vm, node, --n_trace);
+	      t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
+	      t0->session_index = s0->session_index;
+	      t0->server_thread_index = s0->thread_index;
+	    }
+
+	  if (1)
+	    {
+	      ELOG_TYPE_DECLARE (e) =
+	      {
+	      .format = "evt-dequeue: id %d length %d",.format_args =
+		  "i4i4",};
+	      struct
+	      {
+		u32 data[2];
+	      } *ed;
+	      ed = ELOG_DATA (&vm->elog_main, e);
+	      ed->data[0] = e0->event_id;
+	      ed->data[1] = e0->enqueue_length;
+	    }
+
+	  len_to_deq0 = (left_to_snd0 < snd_mss0) ? left_to_snd0 : snd_mss0;
+
+	  /* Make room for headers */
+	  data0 = vlib_buffer_make_headroom (b0, MAX_HDRS_LEN);
+
+	  /* Dequeue the data
+	   * TODO 1) peek instead of dequeue
+	   *      2) buffer chains */
+	  if (peek_data)
+	    {
+	      int n_bytes_read;
+	      n_bytes_read = svm_fifo_peek (s0->server_tx_fifo, s0->pid,
+					    rx_offset, len_to_deq0, data0);
+	      if (n_bytes_read < 0)
+		goto dequeue_fail;
+
+	      /* Keep track of progress locally, transport is also supposed to
+	       * increment it independently when pushing header */
+	      rx_offset += n_bytes_read;
+	    }
+	  else
+	    {
+	      if (svm_fifo_dequeue_nowait (s0->server_tx_fifo, s0->pid,
+					   len_to_deq0, data0) < 0)
+		goto dequeue_fail;
+	    }
+
+	  b0->current_length = len_to_deq0;
+
+	  /* Ask transport to push header */
+	  transport_vft->push_header (tc0, b0);
+
+	  left_to_snd0 -= len_to_deq0;
+	  *n_tx_packets = *n_tx_packets + 1;
+
+	  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);
+    }
+
+  /* If we couldn't dequeue all bytes store progress */
+  if (max_len_to_snd0 < e0->enqueue_length)
+    {
+      e0->enqueue_length -= max_len_to_snd0;
+      vec_add1 (smm->evts_partially_read[thread_index], *e0);
+    }
+  return 0;
+
+dequeue_fail:
+  /* Can't read from fifo. Store event rx progress, save as partially read,
+   * return buff to free list and return  */
+  e0->enqueue_length -= max_len_to_snd0 - left_to_snd0;
+  vec_add1 (smm->evts_partially_read[thread_index], *e0);
+
+  to_next -= 1;
+  n_left_to_next += 1;
+  _vec_len (smm->tx_buffers[thread_index]) += 1;
+
+  clib_warning ("dequeue fail");
+  return 0;
+}
+
+int
+session_fifo_rx_peek (vlib_main_t * vm, vlib_node_runtime_t * node,
+		      session_manager_main_t * smm, session_fifo_event_t * e0,
+		      stream_session_t * s0, u32 thread_index, int *n_tx_pkts)
+{
+  return session_fifo_rx_i (vm, node, smm, e0, s0, thread_index, n_tx_pkts,
+			    1);
+}
+
+int
+session_fifo_rx_dequeue (vlib_main_t * vm, vlib_node_runtime_t * node,
+			 session_manager_main_t * smm,
+			 session_fifo_event_t * e0, stream_session_t * s0,
+			 u32 thread_index, int *n_tx_pkts)
+{
+  return session_fifo_rx_i (vm, node, smm, e0, s0, thread_index, n_tx_pkts,
+			    0);
+}
+
+static uword
+session_queue_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+		       vlib_frame_t * frame)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  session_fifo_event_t *my_fifo_events, *e;
+  u32 n_to_dequeue;
+  unix_shared_memory_queue_t *q;
+  int n_tx_packets = 0;
+  u32 my_thread_index = vm->cpu_index;
+  int i, rv;
+
+  /*
+   *  Update TCP time
+   */
+  tcp_update_time (vlib_time_now (vm), my_thread_index);
+
+  /*
+   * Get vpp queue events
+   */
+  q = smm->vpp_event_queues[my_thread_index];
+  if (PREDICT_FALSE (q == 0))
+    return 0;
+
+  /* min number of events we can dequeue without blocking */
+  n_to_dequeue = q->cursize;
+  if (n_to_dequeue == 0)
+    return 0;
+
+  my_fifo_events = smm->fifo_events[my_thread_index];
+
+  /* If we didn't manage to process previous events try going
+   * over them again without dequeuing new ones.
+   * XXX: Block senders to sessions that can't keep up */
+  if (vec_len (my_fifo_events) >= 100)
+    goto skip_dequeue;
+
+  /* See you in the next life, don't be late */
+  if (pthread_mutex_trylock (&q->mutex))
+    return 0;
+
+  for (i = 0; i < n_to_dequeue; i++)
+    {
+      vec_add2 (my_fifo_events, e, 1);
+      unix_shared_memory_queue_sub_raw (q, (u8 *) e);
+    }
+
+  /* The other side of the connection is not polling */
+  if (q->cursize < (q->maxsize / 8))
+    (void) pthread_cond_broadcast (&q->condvar);
+  pthread_mutex_unlock (&q->mutex);
+
+  smm->fifo_events[my_thread_index] = my_fifo_events;
+
+skip_dequeue:
+
+  for (i = 0; i < n_to_dequeue; i++)
+    {
+      svm_fifo_t *f0;		/* $$$ prefetch 1 ahead maybe */
+      stream_session_t *s0;
+      u32 server_session_index0, server_thread_index0;
+      session_fifo_event_t *e0;
+
+      e0 = &my_fifo_events[i];
+      f0 = e0->fifo;
+      server_session_index0 = f0->server_session_index;
+      server_thread_index0 = f0->server_thread_index;
+
+      /* $$$ add multiple event queues, per vpp worker thread */
+      ASSERT (server_thread_index0 == my_thread_index);
+
+      s0 = pool_elt_at_index (smm->sessions[my_thread_index],
+			      server_session_index0);
+
+      ASSERT (s0->thread_index == my_thread_index);
+
+      switch (e0->event_type)
+	{
+	case FIFO_EVENT_SERVER_TX:
+	  /* Spray packets in per session type frames, since they go to
+	   * different nodes */
+	  rv = (smm->session_rx_fns[s0->session_type]) (vm, node, smm, e0, s0,
+							my_thread_index,
+							&n_tx_packets);
+	  if (rv < 0)
+	    goto done;
+
+	  break;
+
+	default:
+	  clib_warning ("unhandled event type %d", e0->event_type);
+	}
+    }
+
+done:
+
+  /* Couldn't process all events. Probably out of buffers */
+  if (PREDICT_FALSE (i < n_to_dequeue))
+    {
+      session_fifo_event_t *partially_read =
+	smm->evts_partially_read[my_thread_index];
+      vec_add (partially_read, &my_fifo_events[i], n_to_dequeue - i);
+      vec_free (my_fifo_events);
+      smm->fifo_events[my_thread_index] = partially_read;
+      smm->evts_partially_read[my_thread_index] = 0;
+    }
+  else
+    {
+      vec_free (smm->fifo_events[my_thread_index]);
+      smm->fifo_events[my_thread_index] =
+	smm->evts_partially_read[my_thread_index];
+      smm->evts_partially_read[my_thread_index] = 0;
+    }
+
+  vlib_node_increment_counter (vm, session_queue_node.index,
+			       SESSION_QUEUE_ERROR_TX, n_tx_packets);
+
+  return n_tx_packets;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (session_queue_node) =
+{
+  .function = session_queue_node_fn,
+  .name = "session-queue",
+  .format_trace = format_session_queue_trace,
+  .type = VLIB_NODE_TYPE_INPUT,
+  .n_errors = ARRAY_LEN (session_queue_error_strings),
+  .error_strings = session_queue_error_strings,
+  .n_next_nodes = SESSION_QUEUE_N_NEXT,
+  /* .state = VLIB_NODE_STATE_DISABLED, enable on-demand? */
+  /* edit / add dispositions here */
+  .next_nodes =
+  {
+      [SESSION_QUEUE_NEXT_DROP] = "error-drop",
+      [SESSION_QUEUE_NEXT_IP4_LOOKUP] = "ip4-lookup",
+      [SESSION_QUEUE_NEXT_IP6_LOOKUP] = "ip6-lookup",
+      [SESSION_QUEUE_NEXT_TCP_IP4_OUTPUT] = "tcp4-output",
+      [SESSION_QUEUE_NEXT_TCP_IP6_OUTPUT] = "tcp6-output",
+  },
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/session.api b/src/vnet/session/session.api
new file mode 100644
index 00000000000..a7b28c1dba0
--- /dev/null
+++ b/src/vnet/session/session.api
@@ -0,0 +1,429 @@
+/*
+ * Copyright (c) 2015-2016 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.
+ */
+ 
+ /** \brief Bind to a given URI
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param accept_cookie - sender accept cookie, to identify this bind flavor
+    @param uri - a URI, e.g. "tcp://0.0.0.0/0/80" [ipv4]
+                 "tcp://::/0/80" [ipv6] etc.
+    @param options - socket options, fifo sizes, etc.
+*/
+define bind_uri {
+  u32 client_index;
+  u32 context;
+  u32 accept_cookie;
+  u32 initial_segment_size;
+  u8 uri[128];
+  u64 options[16];
+};
+
+/** \brief Unbind a given URI
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param uri - a URI, e.g. "tcp://0.0.0.0/0/80" [ipv4]
+                 "tcp://::/0/80" [ipv6], etc.
+    @param options - socket options, fifo sizes, etc.
+*/
+define unbind_uri {
+  u32 client_index;
+  u32 context;
+  u8 uri[128];
+};
+
+/** \brief Connect to a given URI
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param accept_cookie - sender accept cookie, to identify this bind flavor
+    @param uri - a URI, e.g. "tcp4://0.0.0.0/0/80"
+                 "tcp6://::/0/80" [ipv6], etc.
+    @param options - socket options, fifo sizes, etc.
+*/
+define connect_uri {
+  u32 client_index;
+  u32 context;
+  u8 uri[128];
+  u64 client_queue_address;
+  u64 options[16];
+};
+
+/** \brief Bind reply
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+    @param event_queue_address - vpp event queue address or 0 if this 
+                                 connection shouldn't send events
+    @param segment_name_length - length of segment name 
+    @param segment_name - name of segment client needs to attach to
+*/
+define bind_uri_reply {
+    u32 context;
+    i32 retval;
+    u64 server_event_queue_address;
+    u8 segment_name_length;
+    u32 segment_size;
+    u8 segment_name[128];
+};
+
+/** \brief unbind reply
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+*/
+define unbind_uri_reply {
+    u32 context;
+    i32 retval;
+};
+
+/** \brief vpp->client, connect reply
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+    @param server_rx_fifo - rx (vpp -> vpp-client) fifo address 
+    @param server_tx_fifo - tx (vpp-client -> vpp) fifo address 
+    @param session_index - session index;
+    @param session_thread_index - session thread index
+    @param session_type - session thread type
+    @param vpp_event_queue_address - vpp's event queue address
+    @param client_event_queue_address - client's event queue address
+    @param segment_name_length - non-zero if the client needs to attach to 
+                                 the fifo segment
+    @param segment_name - set if the client needs to attach to the segment
+*/
+define connect_uri_reply {
+  u32 context;
+  i32 retval;
+  u64 server_rx_fifo;
+  u64 server_tx_fifo;
+  u32 session_index;
+  u32 session_thread_index;
+  u8 session_type;
+  u64 client_event_queue_address;
+  u64 vpp_event_queue_address;
+  u32 segment_size;
+  u8 segment_name_length;
+  u8 segment_name[128];
+};
+
+/** \brief vpp->client, please map an additional shared memory segment
+    @param context - sender context, to match reply w/ request
+    @param segment_name - 
+*/
+define map_another_segment {
+    u32 client_index;
+    u32 context;
+    u32 segment_size;
+    u8 segment_name[128];
+};
+
+/** \brief client->vpp
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+*/
+define map_another_segment_reply {
+    u32 context;
+    i32 retval;
+};
+
+/** \brief vpp->client, accept this session
+    @param context - sender context, to match reply w/ request
+    @param accept_cookie - tells client which bind flavor just occurred
+    @param rx_fifo_address - rx (vpp -> vpp-client) fifo address 
+    @param tx_fifo_address - tx (vpp-client -> vpp) fifo address 
+    @param session_index - index of new session
+    @param session_thread_index - thread index of new session
+    @param vpp_event_queue_address - vpp's event queue address
+    @param session_type - type of session
+    
+*/
+define accept_session {
+  u32 client_index;
+  u32 context;
+  u32 accept_cookie;
+  u64 server_rx_fifo;
+  u64 server_tx_fifo;
+  u32 session_index;
+  u32 session_thread_index;
+  u64 vpp_event_queue_address;
+  u8 session_type;
+};
+
+/** \brief client->vpp, reply to an accept message
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+    @param session_index - session index from accept_session / connect_reply
+    @param session_thread_index - thread index from accept_session /
+                                  connect_reply
+*/
+define accept_session_reply {
+  u32 context;
+  i32 retval;
+  u8 session_type;
+  u8 session_thread_index;
+  u32 session_index;
+};
+
+/** \brief bidirectional disconnect API
+    @param client_index - opaque cookie to identify the sender
+                          client to vpp direction only
+    @param context - sender context, to match reply w/ request
+    @param session_index - cookie #1 from accept_session / connect_reply
+    @param session_thread_index - cookie #2
+*/
+define disconnect_session {
+  u32 client_index;
+  u32 context;
+  u32 session_index;
+  u32 session_thread_index;
+};
+
+/** \brief bidirectional disconnect reply API
+    @param client_index - opaque cookie to identify the sender
+                          client to vpp direction only
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+    @param session_index - session index from accept_session / connect_reply
+    @param session_thread_index - thread index from accept_session /
+                                  connect_reply
+*/
+define disconnect_session_reply {
+  u32 client_index;
+  u32 context;
+  i32 retval;
+  u32 session_index;
+  u32 session_thread_index;
+};
+
+/** \brief vpp->client reset session API
+    @param client_index - opaque cookie to identify the sender
+                          client to vpp direction only
+    @param context - sender context, to match reply w/ request
+    @param session_index - session index from accept_session / connect_reply
+    @param session_thread_index - thread index from accept_session /
+                                  connect_reply
+*/
+define reset_session {
+  u32 client_index;
+  u32 context;
+  u32 session_index;
+  u32 session_thread_index;
+};
+
+/** \brief client->vpp reset session reply
+    @param client_index - opaque cookie to identify the sender
+                          client to vpp direction only
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+    @param session_index - session index from accept_session / connect_reply
+    @param session_thread_index - thread index from accept_session /
+                                  connect_reply
+*/
+define reset_session_reply {
+  u32 client_index;
+  u32 context;
+  i32 retval;
+  u32 session_index;
+  u32 session_thread_index;
+};
+
+/** \brief Bind to an ip:port pair for a given transport protocol
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param vrf - bind namespace
+    @param is_ip4 - flag that is 1 if ip address family is IPv4
+    @param ip - ip address
+    @param port - port 
+    @param proto - protocol 0 - TCP 1 - UDP
+    @param options - socket options, fifo sizes, etc.
+*/
+define bind_sock {
+  u32 client_index;
+  u32 context;
+  u32 vrf;
+  u8 is_ip4;
+  u8 ip[16];
+  u16 port;
+  u8 proto;
+  u64 options[16];
+};
+
+/** \brief Unbind 
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param handle - bind handle obtained from bind reply
+*/
+define unbind_sock {
+  u32 client_index;
+  u32 context;
+  u64 handle;
+};
+
+/** \brief Connect to a remote peer
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param vrf - connection namespace
+    @param is_ip4 - flag that is 1 if ip address family is IPv4
+    @param ip - ip address
+    @param port - port 
+    @param proto - protocol 0 - TCP 1 - UDP
+    @param client_queue_address - client's API queue address. Non-zero when 
+                                  used to perform redirects
+    @param options - socket options, fifo sizes, etc.
+*/
+define connect_sock {
+  u32 client_index;
+  u32 context;
+  u32 vrf;
+  u8 is_ip4;
+  u8 ip[16];
+  u16 port;
+  u8 proto;
+  u64 client_queue_address;
+  u64 options[16];
+};
+
+/** \brief Bind reply
+    @param context - sender context, to match reply w/ request
+    @param handle - bind handle
+    @param retval - return code for the request
+    @param event_queue_address - vpp event queue address or 0 if this 
+                                 connection shouldn't send events
+    @param segment_name_length - length of segment name 
+    @param segment_name - name of segment client needs to attach to
+*/
+define bind_sock_reply {
+  u32 context;
+  u64 handle;
+  i32 retval;
+  u64 server_event_queue_address;
+  u32 segment_size;
+  u8 segment_name_length;
+  u8 segment_name[128];
+};
+
+/** \brief unbind reply
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+*/
+define unbind_sock_reply {
+  u32 context;
+  i32 retval;
+};
+
+/** \brief vpp/server->client, connect reply
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+    @param handle - connection handle
+    @param server_rx_fifo - rx (vpp -> vpp-client) fifo address 
+    @param server_tx_fifo - tx (vpp-client -> vpp) fifo address 
+    @param vpp_event_queue_address - vpp's event queue address
+    @param client_event_queue_address - client's event queue address
+    @param segment_name_length - non-zero if the client needs to attach to 
+                                 the fifo segment
+    @param segment_name - set if the client needs to attach to the segment
+*/
+define connect_sock_reply {
+  u32 context;
+  i32 retval;
+  u64 handle;
+  u64 server_rx_fifo;
+  u64 server_tx_fifo;
+  u64 client_event_queue_address;
+  u64 vpp_event_queue_address;
+  u32 segment_size;
+  u8 segment_name_length;
+  u8 segment_name[128];
+};
+
+/** \brief bidirectional disconnect API
+    @param client_index - opaque cookie to identify the sender
+                          client to vpp direction only
+    @param context - sender context, to match reply w/ request
+    @param handle - session handle obtained through accept/connect
+*/
+define disconnect_sock {
+  u32 client_index;
+  u32 context;
+  u64 handle;
+};
+
+/** \brief bidirectional disconnect reply API
+    @param client_index - opaque cookie to identify the sender
+                          client to vpp direction only
+    @param client_context - sender context, to match reply w/ request
+    @param handle - session handle obtained through accept/connect
+*/
+define disconnect_sock_reply {
+  u32 client_index;
+  u32 context;
+  i32 retval;
+  u64 handle;
+};
+
+/** \brief vpp->client, accept this session
+    @param context - sender context, to match reply w/ request
+    @param accept_cookie - tells client which bind flavor just occurred
+    @param handle - session handle obtained through accept/connect
+    @param rx_fifo_address - rx (vpp -> vpp-client) fifo address 
+    @param tx_fifo_address - tx (vpp-client -> vpp) fifo address 
+    @param vpp_event_queue_address - vpp's event queue address
+*/
+define accept_sock {
+  u32 client_index;
+  u32 context;
+  u32 accept_cookie;
+  u64 handle;
+  u64 server_rx_fifo;
+  u64 server_tx_fifo;
+  u64 vpp_event_queue_address;
+};
+
+/** \brief client->vpp, reply to an accept message
+    @param context - sender context, to match reply w/ request
+    @param retval - return code for the request
+    @param handle - session handle obtained through accept/connect
+*/
+define accept_sock_reply {
+  u32 context;
+  i32 retval;
+  u64 handle;
+};
+
+/** \brief vpp->client reset session API
+    @param client_index - opaque cookie to identify the sender
+                          client to vpp direction only
+    @param context - sender context, to match reply w/ request
+    @param handle - session handle obtained through accept/connect
+*/
+define reset_sock {
+  u32 client_index;
+  u32 context;
+  u64 handle;
+};
+
+/** \brief client->vpp reset session reply
+    @param client_index - opaque cookie to identify the sender
+                          client to vpp direction only
+    @param context - sender context, to match reply w/ request
+    @param handle - session handle obtained through accept/connect
+*/
+define reset_sock_reply {
+  u32 client_index;
+  u32 context;
+  i32 retval;
+  u64 handle;
+};
+/*
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
\ No newline at end of file
diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
new file mode 100644
index 00000000000..539da613367
--- /dev/null
+++ b/src/vnet/session/session.c
@@ -0,0 +1,1286 @@
+/*
+ * Copyright (c) 2017 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.
+ */
+/**
+ * @file
+ * @brief Session and session manager
+ */
+
+#include <vnet/session/session.h>
+#include <vlibmemory/api.h>
+#include <vnet/dpo/load_balance.h>
+#include <vnet/fib/ip4_fib.h>
+#include <vnet/session/application.h>
+
+/**
+ * Per-type vector of transport protocol virtual function tables
+ */
+static transport_proto_vft_t *tp_vfts;
+
+session_manager_main_t session_manager_main;
+
+/*
+ * Session lookup key; (src-ip, dst-ip, src-port, dst-port, session-type)
+ * Value: (owner thread index << 32 | session_index);
+ */
+static void
+stream_session_table_add_for_tc (u8 sst, transport_connection_t * tc,
+				 u64 value)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  session_kv4_t kv4;
+  session_kv6_t kv6;
+
+  switch (sst)
+    {
+    case SESSION_TYPE_IP4_UDP:
+    case SESSION_TYPE_IP4_TCP:
+      make_v4_ss_kv_from_tc (&kv4, tc);
+      kv4.value = value;
+      clib_bihash_add_del_16_8 (&smm->v4_session_hash, &kv4, 1 /* is_add */ );
+      break;
+    case SESSION_TYPE_IP6_UDP:
+    case SESSION_TYPE_IP6_TCP:
+      make_v6_ss_kv_from_tc (&kv6, tc);
+      kv6.value = value;
+      clib_bihash_add_del_48_8 (&smm->v6_session_hash, &kv6, 1 /* is_add */ );
+      break;
+    default:
+      clib_warning ("Session type not supported");
+      ASSERT (0);
+    }
+}
+
+void
+stream_session_table_add (session_manager_main_t * smm, stream_session_t * s,
+			  u64 value)
+{
+  transport_connection_t *tc;
+
+  tc = tp_vfts[s->session_type].get_connection (s->connection_index,
+						s->thread_index);
+  stream_session_table_add_for_tc (s->session_type, tc, value);
+}
+
+static void
+stream_session_half_open_table_add (u8 sst, transport_connection_t * tc,
+				    u64 value)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  session_kv4_t kv4;
+  session_kv6_t kv6;
+
+  switch (sst)
+    {
+    case SESSION_TYPE_IP4_UDP:
+    case SESSION_TYPE_IP4_TCP:
+      make_v4_ss_kv_from_tc (&kv4, tc);
+      kv4.value = value;
+      clib_bihash_add_del_16_8 (&smm->v4_half_open_hash, &kv4,
+				1 /* is_add */ );
+      break;
+    case SESSION_TYPE_IP6_UDP:
+    case SESSION_TYPE_IP6_TCP:
+      make_v6_ss_kv_from_tc (&kv6, tc);
+      kv6.value = value;
+      clib_bihash_add_del_48_8 (&smm->v6_half_open_hash, &kv6,
+				1 /* is_add */ );
+      break;
+    default:
+      clib_warning ("Session type not supported");
+      ASSERT (0);
+    }
+}
+
+static int
+stream_session_table_del_for_tc (session_manager_main_t * smm, u8 sst,
+				 transport_connection_t * tc)
+{
+  session_kv4_t kv4;
+  session_kv6_t kv6;
+
+  switch (sst)
+    {
+    case SESSION_TYPE_IP4_UDP:
+    case SESSION_TYPE_IP4_TCP:
+      make_v4_ss_kv_from_tc (&kv4, tc);
+      return clib_bihash_add_del_16_8 (&smm->v4_session_hash, &kv4,
+				       0 /* is_add */ );
+      break;
+    case SESSION_TYPE_IP6_UDP:
+    case SESSION_TYPE_IP6_TCP:
+      make_v6_ss_kv_from_tc (&kv6, tc);
+      return clib_bihash_add_del_48_8 (&smm->v6_session_hash, &kv6,
+				       0 /* is_add */ );
+      break;
+    default:
+      clib_warning ("Session type not supported");
+      ASSERT (0);
+    }
+
+  return 0;
+}
+
+static int
+stream_session_table_del (session_manager_main_t * smm, stream_session_t * s)
+{
+  transport_connection_t *ts;
+
+  ts = tp_vfts[s->session_type].get_connection (s->connection_index,
+						s->thread_index);
+  return stream_session_table_del_for_tc (smm, s->session_type, ts);
+}
+
+static void
+stream_session_half_open_table_del (session_manager_main_t * smm, u8 sst,
+				    transport_connection_t * tc)
+{
+  session_kv4_t kv4;
+  session_kv6_t kv6;
+
+  switch (sst)
+    {
+    case SESSION_TYPE_IP4_UDP:
+    case SESSION_TYPE_IP4_TCP:
+      make_v4_ss_kv_from_tc (&kv4, tc);
+      clib_bihash_add_del_16_8 (&smm->v4_half_open_hash, &kv4,
+				0 /* is_add */ );
+      break;
+    case SESSION_TYPE_IP6_UDP:
+    case SESSION_TYPE_IP6_TCP:
+      make_v6_ss_kv_from_tc (&kv6, tc);
+      clib_bihash_add_del_48_8 (&smm->v6_half_open_hash, &kv6,
+				0 /* is_add */ );
+      break;
+    default:
+      clib_warning ("Session type not supported");
+      ASSERT (0);
+    }
+}
+
+stream_session_t *
+stream_session_lookup_listener4 (ip4_address_t * lcl, u16 lcl_port, u8 proto)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  session_kv4_t kv4;
+  int rv;
+
+  make_v4_listener_kv (&kv4, lcl, lcl_port, proto);
+  rv = clib_bihash_search_inline_16_8 (&smm->v4_session_hash, &kv4);
+  if (rv == 0)
+    return pool_elt_at_index (smm->listen_sessions[proto], (u32) kv4.value);
+
+  /* Zero out the lcl ip */
+  kv4.key[0] = 0;
+  rv = clib_bihash_search_inline_16_8 (&smm->v4_session_hash, &kv4);
+  if (rv == 0)
+    return pool_elt_at_index (smm->listen_sessions[proto], kv4.value);
+
+  return 0;
+}
+
+/** Looks up a session based on the 5-tuple passed as argument.
+ *
+ * First it tries to find an established session, if this fails, it tries
+ * finding a listener session if this fails, it tries a lookup with a
+ * wildcarded local source (listener bound to all interfaces)
+ */
+stream_session_t *
+stream_session_lookup4 (ip4_address_t * lcl, ip4_address_t * rmt,
+			u16 lcl_port, u16 rmt_port, u8 proto,
+			u32 my_thread_index)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  session_kv4_t kv4;
+  int rv;
+
+  /* Lookup session amongst established ones */
+  make_v4_ss_kv (&kv4, lcl, rmt, lcl_port, rmt_port, proto);
+  rv = clib_bihash_search_inline_16_8 (&smm->v4_session_hash, &kv4);
+  if (rv == 0)
+    return stream_session_get_tsi (kv4.value, my_thread_index);
+
+  /* If nothing is found, check if any listener is available */
+  return stream_session_lookup_listener4 (lcl, lcl_port, proto);
+}
+
+stream_session_t *
+stream_session_lookup_listener6 (ip6_address_t * lcl, u16 lcl_port, u8 proto)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  session_kv6_t kv6;
+  int rv;
+
+  make_v6_listener_kv (&kv6, lcl, lcl_port, proto);
+  rv = clib_bihash_search_inline_48_8 (&smm->v6_session_hash, &kv6);
+  if (rv == 0)
+    return pool_elt_at_index (smm->listen_sessions[proto], kv6.value);
+
+  /* Zero out the lcl ip */
+  kv6.key[0] = kv6.key[1] = 0;
+  rv = clib_bihash_search_inline_48_8 (&smm->v6_session_hash, &kv6);
+  if (rv == 0)
+    return pool_elt_at_index (smm->listen_sessions[proto], kv6.value);
+
+  return 0;
+}
+
+/* Looks up a session based on the 5-tuple passed as argument.
+ * First it tries to find an established session, if this fails, it tries
+ * finding a listener session if this fails, it tries a lookup with a
+ * wildcarded local source (listener bound to all interfaces) */
+stream_session_t *
+stream_session_lookup6 (ip6_address_t * lcl, ip6_address_t * rmt,
+			u16 lcl_port, u16 rmt_port, u8 proto,
+			u32 my_thread_index)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  session_kv6_t kv6;
+  int rv;
+
+  make_v6_ss_kv (&kv6, lcl, rmt, lcl_port, rmt_port, proto);
+  rv = clib_bihash_search_inline_48_8 (&smm->v6_session_hash, &kv6);
+  if (rv == 0)
+    return stream_session_get_tsi (kv6.value, my_thread_index);
+
+  /* If nothing is found, check if any listener is available */
+  return stream_session_lookup_listener6 (lcl, lcl_port, proto);
+}
+
+stream_session_t *
+stream_session_lookup_listener (ip46_address_t * lcl, u16 lcl_port, u8 proto)
+{
+  switch (proto)
+    {
+    case SESSION_TYPE_IP4_UDP:
+    case SESSION_TYPE_IP4_TCP:
+      return stream_session_lookup_listener4 (&lcl->ip4, lcl_port, proto);
+      break;
+    case SESSION_TYPE_IP6_UDP:
+    case SESSION_TYPE_IP6_TCP:
+      return stream_session_lookup_listener6 (&lcl->ip6, lcl_port, proto);
+      break;
+    }
+  return 0;
+}
+
+static u64
+stream_session_half_open_lookup (session_manager_main_t * smm,
+				 ip46_address_t * lcl, ip46_address_t * rmt,
+				 u16 lcl_port, u16 rmt_port, u8 proto)
+{
+  session_kv4_t kv4;
+  session_kv6_t kv6;
+  int rv;
+
+  switch (proto)
+    {
+    case SESSION_TYPE_IP4_UDP:
+    case SESSION_TYPE_IP4_TCP:
+      make_v4_ss_kv (&kv4, &lcl->ip4, &rmt->ip4, lcl_port, rmt_port, proto);
+      rv = clib_bihash_search_inline_16_8 (&smm->v4_half_open_hash, &kv4);
+
+      if (rv == 0)
+	return kv4.value;
+
+      return (u64) ~ 0;
+      break;
+    case SESSION_TYPE_IP6_UDP:
+    case SESSION_TYPE_IP6_TCP:
+      make_v6_ss_kv (&kv6, &lcl->ip6, &rmt->ip6, lcl_port, rmt_port, proto);
+      rv = clib_bihash_search_inline_48_8 (&smm->v6_half_open_hash, &kv6);
+
+      if (rv == 0)
+	return kv6.value;
+
+      return (u64) ~ 0;
+      break;
+    }
+  return 0;
+}
+
+transport_connection_t *
+stream_session_lookup_transport4 (session_manager_main_t * smm,
+				  ip4_address_t * lcl, ip4_address_t * rmt,
+				  u16 lcl_port, u16 rmt_port, u8 proto,
+				  u32 my_thread_index)
+{
+  session_kv4_t kv4;
+  stream_session_t *s;
+  int rv;
+
+  /* Lookup session amongst established ones */
+  make_v4_ss_kv (&kv4, lcl, rmt, lcl_port, rmt_port, proto);
+  rv = clib_bihash_search_inline_16_8 (&smm->v4_session_hash, &kv4);
+  if (rv == 0)
+    {
+      s = stream_session_get_tsi (kv4.value, my_thread_index);
+
+      return tp_vfts[s->session_type].get_connection (s->connection_index,
+						      my_thread_index);
+    }
+
+  /* If nothing is found, check if any listener is available */
+  s = stream_session_lookup_listener4 (lcl, lcl_port, proto);
+  if (s)
+    return tp_vfts[s->session_type].get_listener (s->connection_index);
+
+  /* Finally, try half-open connections */
+  rv = clib_bihash_search_inline_16_8 (&smm->v4_half_open_hash, &kv4);
+  if (rv == 0)
+    return tp_vfts[proto].get_half_open (kv4.value & 0xFFFFFFFF);
+
+  return 0;
+}
+
+transport_connection_t *
+stream_session_lookup_transport6 (session_manager_main_t * smm,
+				  ip6_address_t * lcl, ip6_address_t * rmt,
+				  u16 lcl_port, u16 rmt_port, u8 proto,
+				  u32 my_thread_index)
+{
+  stream_session_t *s;
+  session_kv6_t kv6;
+  int rv;
+
+  make_v6_ss_kv (&kv6, lcl, rmt, lcl_port, rmt_port, proto);
+  rv = clib_bihash_search_inline_48_8 (&smm->v6_session_hash, &kv6);
+  if (rv == 0)
+    {
+      s = stream_session_get_tsi (kv6.value, my_thread_index);
+
+      return tp_vfts[s->session_type].get_connection (s->connection_index,
+						      my_thread_index);
+    }
+
+  /* If nothing is found, check if any listener is available */
+  s = stream_session_lookup_listener6 (lcl, lcl_port, proto);
+  if (s)
+    return tp_vfts[s->session_type].get_listener (s->connection_index);
+
+  /* Finally, try half-open connections */
+  rv = clib_bihash_search_inline_48_8 (&smm->v6_half_open_hash, &kv6);
+  if (rv == 0)
+    return tp_vfts[s->session_type].get_half_open (kv6.value & 0xFFFFFFFF);
+
+  return 0;
+}
+
+/**
+ * Allocate vpp event queue (once) per worker thread
+ */
+void
+vpp_session_event_queue_allocate (session_manager_main_t * smm,
+				  u32 thread_index)
+{
+  api_main_t *am = &api_main;
+  void *oldheap;
+
+  if (smm->vpp_event_queues[thread_index] == 0)
+    {
+      /* Allocate event fifo in the /vpe-api shared-memory segment */
+      oldheap = svm_push_data_heap (am->vlib_rp);
+
+      smm->vpp_event_queues[thread_index] =
+	unix_shared_memory_queue_init (2048 /* nels $$$$ config */ ,
+				       sizeof (session_fifo_event_t),
+				       0 /* consumer pid */ ,
+				       0
+				       /* (do not) send signal when queue non-empty */
+	);
+
+      svm_pop_heap (oldheap);
+    }
+}
+
+void
+session_manager_get_segment_info (u32 index, u8 ** name, u32 * size)
+{
+  svm_fifo_segment_private_t *s;
+  s = svm_fifo_get_segment (index);
+  *name = s->h->segment_name;
+  *size = s->ssvm.ssvm_size;
+}
+
+always_inline int
+session_manager_add_segment_i (session_manager_main_t * smm,
+			       session_manager_t * sm,
+			       u32 segment_size, u8 * segment_name)
+{
+  svm_fifo_segment_create_args_t _ca, *ca = &_ca;
+  int rv;
+
+  memset (ca, 0, sizeof (*ca));
+
+  ca->segment_name = (char *) segment_name;
+  ca->segment_size = segment_size;
+
+  rv = svm_fifo_segment_create (ca);
+  if (rv)
+    {
+      clib_warning ("svm_fifo_segment_create ('%s', %d) failed",
+		    ca->segment_name, ca->segment_size);
+      vec_free (segment_name);
+      return -1;
+    }
+
+  vec_add1 (sm->segment_indices, ca->new_segment_index);
+
+  return 0;
+}
+
+static int
+session_manager_add_segment (session_manager_main_t * smm,
+			     session_manager_t * sm)
+{
+  u8 *segment_name;
+  svm_fifo_segment_create_args_t _ca, *ca = &_ca;
+  u32 add_segment_size;
+  u32 default_segment_size = 128 << 10;
+
+  memset (ca, 0, sizeof (*ca));
+  segment_name = format (0, "%d-%d%c", getpid (),
+			 smm->unique_segment_name_counter++, 0);
+  add_segment_size =
+    sm->add_segment_size ? sm->add_segment_size : default_segment_size;
+
+  return session_manager_add_segment_i (smm, sm, add_segment_size,
+					segment_name);
+}
+
+int
+session_manager_add_first_segment (session_manager_main_t * smm,
+				   session_manager_t * sm, u32 segment_size,
+				   u8 ** segment_name)
+{
+  svm_fifo_segment_create_args_t _ca, *ca = &_ca;
+  memset (ca, 0, sizeof (*ca));
+  *segment_name = format (0, "%d-%d%c", getpid (),
+			  smm->unique_segment_name_counter++, 0);
+  return session_manager_add_segment_i (smm, sm, segment_size, *segment_name);
+}
+
+void
+session_manager_del (session_manager_main_t * smm, session_manager_t * sm)
+{
+  u32 *deleted_sessions = 0;
+  u32 *deleted_thread_indices = 0;
+  int i, j;
+
+  /* Across all fifo segments used by the server */
+  for (j = 0; j < vec_len (sm->segment_indices); j++)
+    {
+      svm_fifo_segment_private_t *fifo_segment;
+      svm_fifo_t **fifos;
+      /* Vector of fifos allocated in the segment */
+      fifo_segment = svm_fifo_get_segment (sm->segment_indices[j]);
+      fifos = (svm_fifo_t **) fifo_segment->h->fifos;
+
+      /*
+       * Remove any residual sessions from the session lookup table
+       * Don't bother deleting the individual fifos, we're going to
+       * throw away the fifo segment in a minute.
+       */
+      for (i = 0; i < vec_len (fifos); i++)
+	{
+	  svm_fifo_t *fifo;
+	  u32 session_index, thread_index;
+	  stream_session_t *session;
+
+	  fifo = fifos[i];
+	  session_index = fifo->server_session_index;
+	  thread_index = fifo->server_thread_index;
+
+	  session = pool_elt_at_index (smm->sessions[thread_index],
+				       session_index);
+
+	  /* Add to the deleted_sessions vector (once!) */
+	  if (!session->is_deleted)
+	    {
+	      session->is_deleted = 1;
+	      vec_add1 (deleted_sessions,
+			session - smm->sessions[thread_index]);
+	      vec_add1 (deleted_thread_indices, thread_index);
+	    }
+	}
+
+      for (i = 0; i < vec_len (deleted_sessions); i++)
+	{
+	  stream_session_t *session;
+
+	  session =
+	    pool_elt_at_index (smm->sessions[deleted_thread_indices[i]],
+			       deleted_sessions[i]);
+
+	  /* Instead of directly removing the session call disconnect */
+	  stream_session_disconnect (session);
+
+	  /*
+	     stream_session_table_del (smm, session);
+	     pool_put(smm->sessions[deleted_thread_indices[i]], session);
+	   */
+	}
+
+      vec_reset_length (deleted_sessions);
+      vec_reset_length (deleted_thread_indices);
+
+      /* Instead of removing the segment, test when removing the session if
+       * the segment can be removed
+       */
+      /* svm_fifo_segment_delete (fifo_segment); */
+    }
+
+  vec_free (deleted_sessions);
+  vec_free (deleted_thread_indices);
+}
+
+int
+session_manager_allocate_session_fifos (session_manager_main_t * smm,
+					session_manager_t * sm,
+					svm_fifo_t ** server_rx_fifo,
+					svm_fifo_t ** server_tx_fifo,
+					u32 * fifo_segment_index,
+					u8 * added_a_segment)
+{
+  svm_fifo_segment_private_t *fifo_segment;
+  u32 fifo_size, default_fifo_size = 8192 /* TODO config */ ;
+  int i;
+
+  *added_a_segment = 0;
+
+  /* Allocate svm fifos */
+  ASSERT (vec_len (sm->segment_indices));
+
+again:
+  for (i = 0; i < vec_len (sm->segment_indices); i++)
+    {
+      *fifo_segment_index = sm->segment_indices[i];
+      fifo_segment = svm_fifo_get_segment (*fifo_segment_index);
+
+      fifo_size = sm->rx_fifo_size;
+      fifo_size = (fifo_size == 0) ? default_fifo_size : fifo_size;
+      *server_rx_fifo = svm_fifo_segment_alloc_fifo (fifo_segment, fifo_size);
+
+      fifo_size = sm->tx_fifo_size;
+      fifo_size = (fifo_size == 0) ? default_fifo_size : fifo_size;
+      *server_tx_fifo = svm_fifo_segment_alloc_fifo (fifo_segment, fifo_size);
+
+      if (*server_rx_fifo == 0)
+	{
+	  /* This would be very odd, but handle it... */
+	  if (*server_tx_fifo != 0)
+	    {
+	      svm_fifo_segment_free_fifo (fifo_segment, *server_tx_fifo);
+	      *server_tx_fifo = 0;
+	    }
+	  continue;
+	}
+      if (*server_tx_fifo == 0)
+	{
+	  if (*server_rx_fifo != 0)
+	    {
+	      svm_fifo_segment_free_fifo (fifo_segment, *server_rx_fifo);
+	      *server_rx_fifo = 0;
+	    }
+	  continue;
+	}
+      break;
+    }
+
+  /* See if we're supposed to create another segment */
+  if (*server_rx_fifo == 0)
+    {
+      if (sm->add_segment)
+	{
+	  if (*added_a_segment)
+	    {
+	      clib_warning ("added a segment, still cant allocate a fifo");
+	      return SESSION_ERROR_NEW_SEG_NO_SPACE;
+	    }
+
+	  if (session_manager_add_segment (smm, sm))
+	    return VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
+
+	  *added_a_segment = 1;
+	  goto again;
+	}
+      else
+	return SESSION_ERROR_NO_SPACE;
+    }
+  return 0;
+}
+
+int
+stream_session_create_i (session_manager_main_t * smm, application_t * app,
+			 transport_connection_t * tc,
+			 stream_session_t ** ret_s)
+{
+  int rv;
+  svm_fifo_t *server_rx_fifo = 0, *server_tx_fifo = 0;
+  u32 fifo_segment_index;
+  u32 pool_index, seg_size;
+  stream_session_t *s;
+  u64 value;
+  u32 thread_index = tc->thread_index;
+  session_manager_t *sm;
+  u8 segment_added;
+  u8 *seg_name;
+
+  sm = session_manager_get (app->session_manager_index);
+
+  /* Check the API queue */
+  if (app->mode == APP_SERVER && application_api_queue_is_full (app))
+    return SESSION_ERROR_API_QUEUE_FULL;
+
+  if ((rv = session_manager_allocate_session_fifos (smm, sm, &server_rx_fifo,
+						    &server_tx_fifo,
+						    &fifo_segment_index,
+						    &segment_added)))
+    return rv;
+
+  if (segment_added && app->mode == APP_SERVER)
+    {
+      /* Send an API message to the external server, to map new segment */
+      ASSERT (app->cb_fns.add_segment_callback);
+
+      session_manager_get_segment_info (fifo_segment_index, &seg_name,
+					&seg_size);
+      if (app->cb_fns.add_segment_callback (app->api_client_index, seg_name,
+					    seg_size))
+	return VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
+    }
+
+  /* Create the session */
+  pool_get (smm->sessions[thread_index], s);
+  memset (s, 0, sizeof (*s));
+
+  /* Initialize backpointers */
+  pool_index = s - smm->sessions[thread_index];
+  server_rx_fifo->server_session_index = pool_index;
+  server_rx_fifo->server_thread_index = thread_index;
+
+  server_tx_fifo->server_session_index = pool_index;
+  server_tx_fifo->server_thread_index = thread_index;
+
+  s->server_rx_fifo = server_rx_fifo;
+  s->server_tx_fifo = server_tx_fifo;
+
+  /* Initialize state machine, such as it is... */
+  s->session_type = app->session_type;
+  s->session_state = SESSION_STATE_CONNECTING;
+  s->app_index = application_get_index (app);
+  s->server_segment_index = fifo_segment_index;
+  s->thread_index = thread_index;
+  s->session_index = pool_index;
+
+  /* Attach transport to session */
+  s->connection_index = tc->c_index;
+
+  /* Attach session to transport */
+  tc->s_index = s->session_index;
+
+  /* Add to the main lookup table */
+  value = (((u64) thread_index) << 32) | (u64) s->session_index;
+  stream_session_table_add_for_tc (app->session_type, tc, value);
+
+  *ret_s = s;
+
+  return 0;
+}
+
+/*
+ * Enqueue data for delivery to session peer. Does not notify peer of enqueue
+ * event but on request can queue notification events for later delivery by
+ * calling stream_server_flush_enqueue_events().
+ *
+ * @param tc Transport connection which is to be enqueued data
+ * @param data Data to be enqueued
+ * @param len Length of data to be enqueued
+ * @param queue_event Flag to indicate if peer is to be notified or if event
+ *                    is to be queued. The former is useful when more data is
+ *                    enqueued and only one event is to be generated.
+ * @return Number of bytes enqueued or a negative value if enqueueing failed.
+ */
+int
+stream_session_enqueue_data (transport_connection_t * tc, u8 * data, u16 len,
+			     u8 queue_event)
+{
+  stream_session_t *s;
+  int enqueued;
+
+  s = stream_session_get (tc->s_index, tc->thread_index);
+
+  /* Make sure there's enough space left. We might've filled the pipes */
+  if (PREDICT_FALSE (len > svm_fifo_max_enqueue (s->server_rx_fifo)))
+    return -1;
+
+  enqueued = svm_fifo_enqueue_nowait (s->server_rx_fifo, s->pid, len, data);
+
+  if (queue_event)
+    {
+      /* Queue RX event on this fifo. Eventually these will need to be flushed
+       * by calling stream_server_flush_enqueue_events () */
+      session_manager_main_t *smm = vnet_get_session_manager_main ();
+      u32 thread_index = s->thread_index;
+      u32 my_enqueue_epoch = smm->current_enqueue_epoch[thread_index];
+
+      if (s->enqueue_epoch != my_enqueue_epoch)
+	{
+	  s->enqueue_epoch = my_enqueue_epoch;
+	  vec_add1 (smm->session_indices_to_enqueue_by_thread[thread_index],
+		    s - smm->sessions[thread_index]);
+	}
+    }
+
+  return enqueued;
+}
+
+/** Check if we have space in rx fifo to push more bytes */
+u8
+stream_session_no_space (transport_connection_t * tc, u32 thread_index,
+			 u16 data_len)
+{
+  stream_session_t *s = stream_session_get (tc->c_index, thread_index);
+
+  if (PREDICT_FALSE (s->session_state != SESSION_STATE_READY))
+    return 1;
+
+  if (data_len > svm_fifo_max_enqueue (s->server_rx_fifo))
+    return 1;
+
+  return 0;
+}
+
+u32
+stream_session_peek_bytes (transport_connection_t * tc, u8 * buffer,
+			   u32 offset, u32 max_bytes)
+{
+  stream_session_t *s = stream_session_get (tc->s_index, tc->thread_index);
+  return svm_fifo_peek (s->server_tx_fifo, s->pid, offset, max_bytes, buffer);
+}
+
+u32
+stream_session_dequeue_drop (transport_connection_t * tc, u32 max_bytes)
+{
+  stream_session_t *s = stream_session_get (tc->s_index, tc->thread_index);
+  return svm_fifo_dequeue_drop (s->server_tx_fifo, s->pid, max_bytes);
+}
+
+/**
+ * Notify session peer that new data has been enqueued.
+ *
+ * @param s Stream session for which the event is to be generated.
+ * @param block Flag to indicate if call should block if event queue is full.
+ *
+ * @return 0 on succes or negative number if failed to send notification.
+ */
+static int
+stream_session_enqueue_notify (stream_session_t * s, u8 block)
+{
+  application_t *app;
+  session_fifo_event_t evt;
+  unix_shared_memory_queue_t *q;
+  static u32 serial_number;
+
+  if (PREDICT_FALSE (s->session_state == SESSION_STATE_CLOSED))
+    return 0;
+
+  /* Get session's server */
+  app = application_get (s->app_index);
+
+  /* Fabricate event */
+  evt.fifo = s->server_rx_fifo;
+  evt.event_type = FIFO_EVENT_SERVER_RX;
+  evt.event_id = serial_number++;
+  evt.enqueue_length = svm_fifo_max_dequeue (s->server_rx_fifo);
+
+  /* Add event to server's event queue */
+  q = app->event_queue;
+
+  /* Based on request block (or not) for lack of space */
+  if (block || PREDICT_TRUE (q->cursize < q->maxsize))
+    unix_shared_memory_queue_add (app->event_queue, (u8 *) & evt,
+				  0 /* do wait for mutex */ );
+  else
+    return -1;
+
+  if (1)
+    {
+      ELOG_TYPE_DECLARE (e) =
+      {
+      .format = "evt-enqueue: id %d length %d",.format_args = "i4i4",};
+      struct
+      {
+	u32 data[2];
+      } *ed;
+      ed = ELOG_DATA (&vlib_global_main.elog_main, e);
+      ed->data[0] = evt.event_id;
+      ed->data[1] = evt.enqueue_length;
+    }
+
+  return 0;
+}
+
+/**
+ * Flushes queue of sessions that are to be notified of new data
+ * enqueued events.
+ *
+ * @param thread_index Thread index for which the flush is to be performed.
+ * @return 0 on success or a positive number indicating the number of
+ *         failures due to API queue being full.
+ */
+int
+session_manager_flush_enqueue_events (u32 thread_index)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  u32 *session_indices_to_enqueue;
+  int i, errors = 0;
+
+  session_indices_to_enqueue =
+    smm->session_indices_to_enqueue_by_thread[thread_index];
+
+  for (i = 0; i < vec_len (session_indices_to_enqueue); i++)
+    {
+      stream_session_t *s0;
+
+      /* Get session */
+      s0 = stream_session_get (session_indices_to_enqueue[i], thread_index);
+      if (stream_session_enqueue_notify (s0, 0 /* don't block */ ))
+	{
+	  errors++;
+	}
+    }
+
+  vec_reset_length (session_indices_to_enqueue);
+
+  smm->session_indices_to_enqueue_by_thread[thread_index] =
+    session_indices_to_enqueue;
+
+  /* Increment enqueue epoch for next round */
+  smm->current_enqueue_epoch[thread_index]++;
+
+  return errors;
+}
+
+/*
+ * Start listening on server's ip/port pair for requested transport.
+ *
+ * Creates a 'dummy' stream session with state LISTENING to be used in session
+ * lookups, prior to establishing connection. Requests transport to build
+ * it's own specific listening connection.
+ */
+int
+stream_session_start_listen (u32 server_index, ip46_address_t * ip, u16 port)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  stream_session_t *s;
+  transport_connection_t *tc;
+  application_t *srv;
+  u32 tci;
+
+  srv = application_get (server_index);
+
+  pool_get (smm->listen_sessions[srv->session_type], s);
+  memset (s, 0, sizeof (*s));
+
+  s->session_type = srv->session_type;
+  s->session_state = SESSION_STATE_LISTENING;
+  s->session_index = s - smm->listen_sessions[srv->session_type];
+  s->app_index = srv->index;
+
+  /* Transport bind/listen  */
+  tci = tp_vfts[srv->session_type].bind (smm->vlib_main, s->session_index, ip,
+					 port);
+
+  /* Attach transport to session */
+  s->connection_index = tci;
+  tc = tp_vfts[srv->session_type].get_listener (tci);
+
+  srv->session_index = s->session_index;
+
+  /* Add to the main lookup table */
+  stream_session_table_add_for_tc (s->session_type, tc, s->session_index);
+
+  return 0;
+}
+
+void
+stream_session_stop_listen (u32 server_index)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  stream_session_t *listener;
+  transport_connection_t *tc;
+  application_t *srv;
+
+  srv = application_get (server_index);
+  listener = pool_elt_at_index (smm->listen_sessions[srv->session_type],
+				srv->session_index);
+
+  tc = tp_vfts[srv->session_type].get_listener (listener->connection_index);
+  stream_session_table_del_for_tc (smm, listener->session_type, tc);
+
+  tp_vfts[srv->session_type].unbind (smm->vlib_main,
+				     listener->connection_index);
+  pool_put (smm->listen_sessions[srv->session_type], listener);
+}
+
+int
+connect_server_add_segment_cb (application_t * ss, char *segment_name,
+			       u32 segment_size)
+{
+  /* Does exactly nothing, but die */
+  ASSERT (0);
+  return 0;
+}
+
+void
+connects_session_manager_init (session_manager_main_t * smm, u8 session_type)
+{
+  session_manager_t *sm;
+  u32 connect_fifo_size = 8 << 10;	/* Config? */
+  u32 default_segment_size = 1 << 20;
+
+  pool_get (smm->session_managers, sm);
+  memset (sm, 0, sizeof (*sm));
+
+  sm->add_segment_size = default_segment_size;
+  sm->rx_fifo_size = connect_fifo_size;
+  sm->tx_fifo_size = connect_fifo_size;
+  sm->add_segment = 1;
+
+  session_manager_add_segment (smm, sm);
+  smm->connect_manager_index[session_type] = sm - smm->session_managers;
+}
+
+void
+stream_session_connect_notify (transport_connection_t * tc, u8 sst,
+			       u8 is_fail)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  application_t *app;
+  stream_session_t *new_s = 0;
+  u64 value;
+
+  value = stream_session_half_open_lookup (smm, &tc->lcl_ip, &tc->rmt_ip,
+					   tc->lcl_port, tc->rmt_port,
+					   tc->proto);
+  if (value == HALF_OPEN_LOOKUP_INVALID_VALUE)
+    {
+      clib_warning ("This can't be good!");
+      return;
+    }
+
+  app = application_get (value >> 32);
+
+  if (!is_fail)
+    {
+      /* Create new session (server segments are allocated if needed) */
+      if (stream_session_create_i (smm, app, tc, &new_s))
+	return;
+
+      app->session_index = stream_session_get_index (new_s);
+      app->thread_index = new_s->thread_index;
+
+      /* Allocate vpp event queue for this thread if needed */
+      vpp_session_event_queue_allocate (smm, tc->thread_index);
+    }
+
+  /* Notify client */
+  app->cb_fns.session_connected_callback (app->api_client_index, new_s,
+					  is_fail);
+
+  /* Cleanup session lookup */
+  stream_session_half_open_table_del (smm, sst, tc);
+}
+
+void
+stream_session_accept_notify (transport_connection_t * tc)
+{
+  application_t *server;
+  stream_session_t *s;
+
+  s = stream_session_get (tc->s_index, tc->thread_index);
+  server = application_get (s->app_index);
+  server->cb_fns.session_accept_callback (s);
+}
+
+/**
+ * Notification from transport that connection is being closed.
+ *
+ * A disconnect is sent to application but state is not removed. Once
+ * disconnect is acknowledged by application, session disconnect is called.
+ * Ultimately this leads to close being called on transport (passive close).
+ */
+void
+stream_session_disconnect_notify (transport_connection_t * tc)
+{
+  application_t *server;
+  stream_session_t *s;
+
+  s = stream_session_get (tc->s_index, tc->thread_index);
+  server = application_get (s->app_index);
+  server->cb_fns.session_disconnect_callback (s);
+}
+
+/**
+ * Cleans up session and associated app if needed.
+ */
+void
+stream_session_delete (stream_session_t * s)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  svm_fifo_segment_private_t *fifo_segment;
+  application_t *app;
+  int rv;
+
+  /* delete from the main lookup table */
+  rv = stream_session_table_del (smm, s);
+
+  if (rv)
+    clib_warning ("hash delete error, rv %d", rv);
+
+  /* Cleanup fifo segments */
+  fifo_segment = svm_fifo_get_segment (s->server_segment_index);
+  svm_fifo_segment_free_fifo (fifo_segment, s->server_rx_fifo);
+  svm_fifo_segment_free_fifo (fifo_segment, s->server_tx_fifo);
+
+  /* Cleanup app if client */
+  app = application_get (s->app_index);
+  if (app->mode == APP_CLIENT)
+    {
+      application_del (app);
+    }
+  else if (app->mode == APP_SERVER)
+    {
+      session_manager_t *sm;
+      svm_fifo_segment_private_t *fifo_segment;
+      svm_fifo_t **fifos;
+      u32 fifo_index;
+
+      sm = session_manager_get (app->session_manager_index);
+
+      /* Delete fifo */
+      fifo_segment = svm_fifo_get_segment (s->server_segment_index);
+      fifos = (svm_fifo_t **) fifo_segment->h->fifos;
+
+      fifo_index = svm_fifo_segment_index (fifo_segment);
+
+      /* Remove segment only if it holds no fifos and not the first */
+      if (sm->segment_indices[0] != fifo_index && vec_len (fifos) == 0)
+	svm_fifo_segment_delete (fifo_segment);
+    }
+
+  pool_put (smm->sessions[s->thread_index], s);
+}
+
+/**
+ * Notification from transport that connection is being deleted
+ *
+ * This should be called only on previously fully established sessions. For
+ * instance failed connects should call stream_session_connect_notify and
+ * indicate that the connect has failed.
+ */
+void
+stream_session_delete_notify (transport_connection_t * tc)
+{
+  stream_session_t *s;
+
+  s = stream_session_get_if_valid (tc->s_index, tc->thread_index);
+  if (!s)
+    {
+      clib_warning ("Surprised!");
+      return;
+    }
+  stream_session_delete (s);
+}
+
+/**
+ * Notify application that connection has been reset.
+ */
+void
+stream_session_reset_notify (transport_connection_t * tc)
+{
+  stream_session_t *s;
+  application_t *app;
+  s = stream_session_get (tc->s_index, tc->thread_index);
+
+  app = application_get (s->app_index);
+  app->cb_fns.session_reset_callback (s);
+}
+
+/**
+ * Accept a stream session. Optionally ping the server by callback.
+ */
+int
+stream_session_accept (transport_connection_t * tc, u32 listener_index,
+		       u8 sst, u8 notify)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  application_t *server;
+  stream_session_t *s, *listener;
+
+  int rv;
+
+  /* Find the server */
+  listener = pool_elt_at_index (smm->listen_sessions[sst], listener_index);
+  server = application_get (listener->app_index);
+
+  if ((rv = stream_session_create_i (smm, server, tc, &s)))
+    return rv;
+
+  /* Allocate vpp event queue for this thread if needed */
+  vpp_session_event_queue_allocate (smm, tc->thread_index);
+
+  /* Shoulder-tap the server */
+  if (notify)
+    {
+      server->cb_fns.session_accept_callback (s);
+    }
+
+  return 0;
+}
+
+void
+stream_session_open (u8 sst, ip46_address_t * addr, u16 port_host_byte_order,
+		     u32 app_index)
+{
+  transport_connection_t *tc;
+  u32 tci;
+  u64 value;
+
+  /* Ask transport to open connection */
+  tci = tp_vfts[sst].open (addr, port_host_byte_order);
+
+  /* Get transport connection */
+  tc = tp_vfts[sst].get_half_open (tci);
+
+  /* Store api_client_index and transport connection index */
+  value = (((u64) app_index) << 32) | (u64) tc->c_index;
+
+  /* Add to the half-open lookup table */
+  stream_session_half_open_table_add (sst, tc, value);
+}
+
+/**
+ * Disconnect session and propagate to transport. This should eventually
+ * result in a delete notification that allows us to cleanup session state.
+ * Called for both active/passive disconnects.
+ */
+void
+stream_session_disconnect (stream_session_t * s)
+{
+  tp_vfts[s->session_type].close (s->connection_index, s->thread_index);
+  s->session_state = SESSION_STATE_CLOSED;
+}
+
+/**
+ * Cleanup transport and session state.
+ */
+void
+stream_session_cleanup (stream_session_t * s)
+{
+  tp_vfts[s->session_type].cleanup (s->connection_index, s->thread_index);
+  stream_session_delete (s);
+}
+
+void
+session_register_transport (u8 type, const transport_proto_vft_t * vft)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+
+  vec_validate (tp_vfts, type);
+  tp_vfts[type] = *vft;
+
+  /* If an offset function is provided, then peek instead of dequeue */
+  smm->session_rx_fns[type] =
+    (vft->rx_fifo_offset) ? session_fifo_rx_peek : session_fifo_rx_dequeue;
+}
+
+transport_proto_vft_t *
+session_get_transport_vft (u8 type)
+{
+  if (type >= vec_len (tp_vfts))
+    return 0;
+  return &tp_vfts[type];
+}
+
+static clib_error_t *
+session_manager_main_init (vlib_main_t * vm)
+{
+  u32 num_threads;
+  vlib_thread_main_t *vtm = vlib_get_thread_main ();
+  session_manager_main_t *smm = &session_manager_main;
+  int i;
+
+  smm->vlib_main = vm;
+  smm->vnet_main = vnet_get_main ();
+
+  num_threads = 1 /* main thread */  + vtm->n_threads;
+
+  if (num_threads < 1)
+    return clib_error_return (0, "n_thread_stacks not set");
+
+  /* $$$ config parameters */
+  svm_fifo_segment_init (0x200000000ULL /* first segment base VA */ ,
+			 20 /* timeout in seconds */ );
+
+  /* configure per-thread ** vectors */
+  vec_validate (smm->sessions, num_threads - 1);
+  vec_validate (smm->session_indices_to_enqueue_by_thread, num_threads - 1);
+  vec_validate (smm->tx_buffers, num_threads - 1);
+  vec_validate (smm->fifo_events, num_threads - 1);
+  vec_validate (smm->evts_partially_read, num_threads - 1);
+  vec_validate (smm->current_enqueue_epoch, num_threads - 1);
+  vec_validate (smm->vpp_event_queues, num_threads - 1);
+
+  /* $$$$ preallocate hack config parameter */
+  for (i = 0; i < 200000; i++)
+    {
+      stream_session_t *ss;
+      pool_get (smm->sessions[0], ss);
+      memset (ss, 0, sizeof (*ss));
+    }
+
+  for (i = 0; i < 200000; i++)
+    pool_put_index (smm->sessions[0], i);
+
+  clib_bihash_init_16_8 (&smm->v4_session_hash, "v4 session table",
+			 200000 /* $$$$ config parameter nbuckets */ ,
+			 (64 << 20) /*$$$ config parameter table size */ );
+  clib_bihash_init_48_8 (&smm->v6_session_hash, "v6 session table",
+			 200000 /* $$$$ config parameter nbuckets */ ,
+			 (64 << 20) /*$$$ config parameter table size */ );
+
+  clib_bihash_init_16_8 (&smm->v4_half_open_hash, "v4 half-open table",
+			 200000 /* $$$$ config parameter nbuckets */ ,
+			 (64 << 20) /*$$$ config parameter table size */ );
+  clib_bihash_init_48_8 (&smm->v6_half_open_hash, "v6 half-open table",
+			 200000 /* $$$$ config parameter nbuckets */ ,
+			 (64 << 20) /*$$$ config parameter table size */ );
+
+  for (i = 0; i < SESSION_N_TYPES; i++)
+    smm->connect_manager_index[i] = INVALID_INDEX;
+
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (session_manager_main_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
new file mode 100644
index 00000000000..cf14cca9f30
--- /dev/null
+++ b/src/vnet/session/session.h
@@ -0,0 +1,380 @@
+/*
+ * Copyright (c) 2017 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_session_h__
+#define __included_session_h__
+
+#include <vnet/session/transport.h>
+#include <vlibmemory/unix_shared_memory_queue.h>
+#include <vlibmemory/api.h>
+#include <vppinfra/sparse_vec.h>
+#include <svm/svm_fifo_segment.h>
+
+#define HALF_OPEN_LOOKUP_INVALID_VALUE ((u64)~0)
+#define INVALID_INDEX ((u32)~0)
+
+/* TODO decide how much since we have pre-data as well */
+#define MAX_HDRS_LEN    100	/* Max number of bytes for headers */
+
+typedef enum
+{
+  FIFO_EVENT_SERVER_RX,
+  FIFO_EVENT_SERVER_TX,
+  FIFO_EVENT_TIMEOUT,
+  FIFO_EVENT_SERVER_EXIT,
+} fifo_event_type_t;
+
+#define foreach_session_input_error                                         \
+_(NO_SESSION, "No session drops")                                       \
+_(NO_LISTENER, "No listener for dst port drops")                        \
+_(ENQUEUED, "Packets pushed into rx fifo")                              \
+_(NOT_READY, "Session not ready packets")                               \
+_(FIFO_FULL, "Packets dropped for lack of rx fifo space")               \
+_(EVENT_FIFO_FULL, "Events not sent for lack of event fifo space")      \
+_(API_QUEUE_FULL, "Sessions not created for lack of API queue space")   \
+_(NEW_SEG_NO_SPACE, "Created segment, couldn't allocate a fifo pair")   \
+_(NO_SPACE, "Couldn't allocate a fifo pair")
+
+typedef enum
+{
+#define _(sym,str) SESSION_ERROR_##sym,
+  foreach_session_input_error
+#undef _
+    SESSION_N_ERROR,
+} session_error_t;
+
+/* Event queue input node static next indices */
+typedef enum
+{
+  SESSION_QUEUE_NEXT_DROP,
+  SESSION_QUEUE_NEXT_TCP_IP4_OUTPUT,
+  SESSION_QUEUE_NEXT_IP4_LOOKUP,
+  SESSION_QUEUE_NEXT_TCP_IP6_OUTPUT,
+  SESSION_QUEUE_NEXT_IP6_LOOKUP,
+  SESSION_QUEUE_N_NEXT,
+} session_queue_next_t;
+
+#define foreach_session_type                    \
+  _(IP4_TCP, ip4_tcp)                           \
+  _(IP4_UDP, ip4_udp)                           \
+  _(IP6_TCP, ip6_tcp)                           \
+  _(IP6_UDP, ip6_udp)
+
+typedef enum
+{
+#define _(A, a) SESSION_TYPE_##A,
+  foreach_session_type
+#undef _
+    SESSION_N_TYPES,
+} session_type_t;
+
+/*
+ * Application session state
+ */
+typedef enum
+{
+  SESSION_STATE_LISTENING,
+  SESSION_STATE_CONNECTING,
+  SESSION_STATE_READY,
+  SESSION_STATE_CLOSED,
+  SESSION_STATE_N_STATES,
+} stream_session_state_t;
+
+typedef CLIB_PACKED (struct
+		     {
+		     svm_fifo_t * fifo;
+		     u8 event_type;
+		     /* $$$$ for event logging */
+		     u16 event_id;
+		     u32 enqueue_length;
+		     }) session_fifo_event_t;
+
+typedef struct _stream_session_t
+{
+  /** Type */
+  u8 session_type;
+
+  /** State */
+  u8 session_state;
+
+  /** Session index in per_thread pool */
+  u32 session_index;
+
+  /** Transport specific */
+  u32 connection_index;
+
+  u8 thread_index;
+
+  /** Application specific */
+  u32 pid;
+
+  /** fifo pointers. Once allocated, these do not move */
+  svm_fifo_t *server_rx_fifo;
+  svm_fifo_t *server_tx_fifo;
+
+  /** To avoid n**2 "one event per frame" check */
+  u8 enqueue_epoch;
+
+  /** used during unbind processing */
+  u8 is_deleted;
+
+  /** stream server pool index */
+  u32 app_index;
+
+  /** svm segment index */
+  u32 server_segment_index;
+} stream_session_t;
+
+typedef struct _session_manager
+{
+  /** segments mapped by this server */
+  u32 *segment_indices;
+
+  /** Session fifo sizes. They are provided for binds and take default
+   * values for connects */
+  u32 rx_fifo_size;
+  u32 tx_fifo_size;
+
+  /** Configured additional segment size */
+  u32 add_segment_size;
+
+  /** Flag that indicates if additional segments should be created */
+  u8 add_segment;
+} session_manager_t;
+
+/* Forward definition */
+typedef struct _session_manager_main session_manager_main_t;
+
+typedef int
+  (session_fifo_rx_fn) (vlib_main_t * vm, vlib_node_runtime_t * node,
+			session_manager_main_t * smm,
+			session_fifo_event_t * e0, stream_session_t * s0,
+			u32 thread_index, int *n_tx_pkts);
+
+extern session_fifo_rx_fn session_fifo_rx_peek;
+extern session_fifo_rx_fn session_fifo_rx_dequeue;
+
+struct _session_manager_main
+{
+  /** Lookup tables for established sessions and listeners */
+  clib_bihash_16_8_t v4_session_hash;
+  clib_bihash_48_8_t v6_session_hash;
+
+  /** Lookup tables for half-open sessions */
+  clib_bihash_16_8_t v4_half_open_hash;
+  clib_bihash_48_8_t v6_half_open_hash;
+
+  /** Per worker thread session pools */
+  stream_session_t **sessions;
+
+  /** Pool of listen sessions. Same type as stream sessions to ease lookups */
+  stream_session_t *listen_sessions[SESSION_N_TYPES];
+
+  /** Sparse vector to map dst port to stream server  */
+  u16 *stream_server_by_dst_port[SESSION_N_TYPES];
+
+  /** per-worker enqueue epoch counters */
+  u8 *current_enqueue_epoch;
+
+  /** Per-worker thread vector of sessions to enqueue */
+  u32 **session_indices_to_enqueue_by_thread;
+
+  /** per-worker tx buffer free lists */
+  u32 **tx_buffers;
+
+  /** Per worker-thread vector of partially read events */
+  session_fifo_event_t **evts_partially_read;
+
+  /** per-worker active event vectors */
+  session_fifo_event_t **fifo_events;
+
+  /** vpp fifo event queue */
+  unix_shared_memory_queue_t **vpp_event_queues;
+
+  /** Unique segment name counter */
+  u32 unique_segment_name_counter;
+
+  /* Connection manager used by incoming connects */
+  u32 connect_manager_index[SESSION_N_TYPES];
+
+  session_manager_t *session_managers;
+
+  /** Per transport rx function that can either dequeue or peek */
+  session_fifo_rx_fn *session_rx_fns[SESSION_N_TYPES];
+
+  /* Convenience */
+  vlib_main_t *vlib_main;
+  vnet_main_t *vnet_main;
+};
+
+extern session_manager_main_t session_manager_main;
+
+/*
+ * Session manager function
+ */
+always_inline session_manager_main_t *
+vnet_get_session_manager_main ()
+{
+  return &session_manager_main;
+}
+
+always_inline session_manager_t *
+session_manager_get (u32 index)
+{
+  return pool_elt_at_index (session_manager_main.session_managers, index);
+}
+
+always_inline unix_shared_memory_queue_t *
+session_manager_get_vpp_event_queue (u32 thread_index)
+{
+  return session_manager_main.vpp_event_queues[thread_index];
+}
+
+always_inline session_manager_t *
+connects_session_manager_get (session_manager_main_t * smm,
+			      session_type_t session_type)
+{
+  return pool_elt_at_index (smm->session_managers,
+			    smm->connect_manager_index[session_type]);
+}
+
+void session_manager_get_segment_info (u32 index, u8 ** name, u32 * size);
+int session_manager_flush_enqueue_events (u32 thread_index);
+int
+session_manager_add_first_segment (session_manager_main_t * smm,
+				   session_manager_t * sm, u32 segment_size,
+				   u8 ** segment_name);
+void
+session_manager_del (session_manager_main_t * smm, session_manager_t * sm);
+void
+connects_session_manager_init (session_manager_main_t * smm, u8 session_type);
+
+/*
+ * Stream session functions
+ */
+
+stream_session_t *stream_session_lookup_listener4 (ip4_address_t * lcl,
+						   u16 lcl_port, u8 proto);
+stream_session_t *stream_session_lookup4 (ip4_address_t * lcl,
+					  ip4_address_t * rmt, u16 lcl_port,
+					  u16 rmt_port, u8 proto,
+					  u32 thread_index);
+stream_session_t *stream_session_lookup_listener6 (ip6_address_t * lcl,
+						   u16 lcl_port, u8 proto);
+stream_session_t *stream_session_lookup6 (ip6_address_t * lcl,
+					  ip6_address_t * rmt, u16 lcl_port,
+					  u16 rmt_port, u8, u32 thread_index);
+transport_connection_t
+  * stream_session_lookup_transport4 (session_manager_main_t * smm,
+				      ip4_address_t * lcl,
+				      ip4_address_t * rmt, u16 lcl_port,
+				      u16 rmt_port, u8 proto,
+				      u32 thread_index);
+transport_connection_t
+  * stream_session_lookup_transport6 (session_manager_main_t * smm,
+				      ip6_address_t * lcl,
+				      ip6_address_t * rmt, u16 lcl_port,
+				      u16 rmt_port, u8 proto,
+				      u32 thread_index);
+stream_session_t *stream_session_lookup_listener (ip46_address_t * lcl,
+						  u16 lcl_port, u8 proto);
+
+always_inline stream_session_t *
+stream_session_get_tsi (u64 ti_and_si, u32 thread_index)
+{
+  ASSERT ((u32) (ti_and_si >> 32) == thread_index);
+  return pool_elt_at_index (session_manager_main.sessions[thread_index],
+			    ti_and_si & 0xFFFFFFFFULL);
+}
+
+always_inline stream_session_t *
+stream_session_get (u64 si, u32 thread_index)
+{
+  return pool_elt_at_index (session_manager_main.sessions[thread_index], si);
+}
+
+always_inline stream_session_t *
+stream_session_get_if_valid (u64 si, u32 thread_index)
+{
+  if (thread_index >= vec_len (session_manager_main.sessions))
+    return 0;
+
+  if (pool_is_free_index (session_manager_main.sessions[thread_index], si))
+    return 0;
+
+  return pool_elt_at_index (session_manager_main.sessions[thread_index], si);
+}
+
+always_inline stream_session_t *
+stream_session_listener_get (u8 sst, u64 si)
+{
+  return pool_elt_at_index (session_manager_main.listen_sessions[sst], si);
+}
+
+always_inline u32
+stream_session_get_index (stream_session_t * s)
+{
+  if (s->session_state == SESSION_STATE_LISTENING)
+    return s - session_manager_main.listen_sessions[s->session_type];
+
+  return s - session_manager_main.sessions[s->thread_index];
+}
+
+always_inline u32
+stream_session_max_enqueue (transport_connection_t * tc)
+{
+  stream_session_t *s = stream_session_get (tc->s_index, tc->thread_index);
+  return svm_fifo_max_enqueue (s->server_rx_fifo);
+}
+
+int
+stream_session_enqueue_data (transport_connection_t * tc, u8 * data, u16 len,
+			     u8 queue_event);
+u32
+stream_session_peek_bytes (transport_connection_t * tc, u8 * buffer,
+			   u32 offset, u32 max_bytes);
+u32 stream_session_dequeue_drop (transport_connection_t * tc, u32 max_bytes);
+
+void
+stream_session_connect_notify (transport_connection_t * tc, u8 sst,
+			       u8 is_fail);
+void stream_session_accept_notify (transport_connection_t * tc);
+void stream_session_disconnect_notify (transport_connection_t * tc);
+void stream_session_delete_notify (transport_connection_t * tc);
+void stream_session_reset_notify (transport_connection_t * tc);
+int
+stream_session_accept (transport_connection_t * tc, u32 listener_index,
+		       u8 sst, u8 notify);
+void stream_session_open (u8 sst, ip46_address_t * addr,
+			  u16 port_host_byte_order, u32 api_client_index);
+void stream_session_disconnect (stream_session_t * s);
+void stream_session_cleanup (stream_session_t * s);
+int
+stream_session_start_listen (u32 server_index, ip46_address_t * ip, u16 port);
+void stream_session_stop_listen (u32 server_index);
+
+u8 *format_stream_session (u8 * s, va_list * args);
+
+void session_register_transport (u8 type, const transport_proto_vft_t * vft);
+transport_proto_vft_t *session_get_transport_vft (u8 type);
+
+#endif /* __included_session_h__ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
new file mode 100644
index 00000000000..9d068684636
--- /dev/null
+++ b/src/vnet/session/session_api.c
@@ -0,0 +1,821 @@
+/*
+ * Copyright (c) 2015-2016 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 <vnet/vnet.h>
+#include <vlibmemory/api.h>
+#include <vnet/session/application.h>
+
+#include <vnet/vnet_msg_enum.h>
+#include "application_interface.h"
+
+#define vl_typedefs		/* define message structures */
+#include <vnet/vnet_all_api_h.h>
+#undef vl_typedefs
+
+#define vl_endianfun		/* define message structures */
+#include <vnet/vnet_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 <vnet/vnet_all_api_h.h>
+#undef vl_printfun
+
+#include <vlibapi/api_helper_macros.h>
+
+#define foreach_session_api_msg                                         \
+_(MAP_ANOTHER_SEGMENT_REPLY, map_another_segment_reply)                 \
+_(BIND_URI, bind_uri)                                                   \
+_(UNBIND_URI, unbind_uri)                                               \
+_(CONNECT_URI, connect_uri)                                             \
+_(DISCONNECT_SESSION, disconnect_session)                               \
+_(DISCONNECT_SESSION_REPLY, disconnect_session_reply)                   \
+_(ACCEPT_SESSION_REPLY, accept_session_reply)                           \
+_(RESET_SESSION_REPLY, reset_session_reply)                   		\
+_(BIND_SOCK, bind_sock) 		                                \
+_(UNBIND_SOCK, unbind_sock)                                             \
+_(CONNECT_SOCK, connect_sock)                                          	\
+_(DISCONNECT_SOCK, disconnect_sock)                               	\
+_(DISCONNECT_SOCK_REPLY, disconnect_sock_reply)                        	\
+_(ACCEPT_SOCK_REPLY, accept_sock_reply)                           	\
+_(RESET_SOCK_REPLY, reset_sock_reply)                   		\
+
+static int
+send_add_segment_callback (u32 api_client_index, const u8 * segment_name,
+			   u32 segment_size)
+{
+  vl_api_map_another_segment_t *mp;
+  unix_shared_memory_queue_t *q;
+
+  q = vl_api_client_index_to_input_queue (api_client_index);
+
+  if (!q)
+    return -1;
+
+  mp = vl_msg_api_alloc (sizeof (*mp));
+  memset (mp, 0, sizeof (*mp));
+  mp->_vl_msg_id = clib_host_to_net_u16 (VL_API_MAP_ANOTHER_SEGMENT);
+  mp->segment_size = segment_size;
+  strncpy ((char *) mp->segment_name, (char *) segment_name,
+	   sizeof (mp->segment_name) - 1);
+
+  vl_msg_api_send_shmem (q, (u8 *) & mp);
+
+  return 0;
+}
+
+static int
+send_session_accept_uri_callback (stream_session_t * s)
+{
+  vl_api_accept_session_t *mp;
+  unix_shared_memory_queue_t *q, *vpp_queue;
+  application_t *server = application_get (s->app_index);
+
+  q = vl_api_client_index_to_input_queue (server->api_client_index);
+  vpp_queue = session_manager_get_vpp_event_queue (s->thread_index);
+
+  if (!q)
+    return -1;
+
+  mp = vl_msg_api_alloc (sizeof (*mp));
+  mp->_vl_msg_id = clib_host_to_net_u16 (VL_API_ACCEPT_SESSION);
+
+  /* Note: session_type is the first octet in all types of sessions */
+
+  mp->accept_cookie = server->accept_cookie;
+  mp->server_rx_fifo = (u64) s->server_rx_fifo;
+  mp->server_tx_fifo = (u64) s->server_tx_fifo;
+  mp->session_thread_index = s->thread_index;
+  mp->session_index = s->session_index;
+  mp->session_type = s->session_type;
+  mp->vpp_event_queue_address = (u64) vpp_queue;
+  vl_msg_api_send_shmem (q, (u8 *) & mp);
+
+  return 0;
+}
+
+static void
+send_session_disconnect_uri_callback (stream_session_t * s)
+{
+  vl_api_disconnect_session_t *mp;
+  unix_shared_memory_queue_t *q;
+  application_t *app = application_get (s->app_index);
+
+  q = vl_api_client_index_to_input_queue (app->api_client_index);
+
+  if (!q)
+    return;
+
+  mp = vl_msg_api_alloc (sizeof (*mp));
+  memset (mp, 0, sizeof (*mp));
+  mp->_vl_msg_id = clib_host_to_net_u16 (VL_API_DISCONNECT_SESSION);
+
+  mp->session_thread_index = s->thread_index;
+  mp->session_index = s->session_index;
+  vl_msg_api_send_shmem (q, (u8 *) & mp);
+}
+
+static int
+send_session_connected_uri_callback (u32 api_client_index,
+				     stream_session_t * s, u8 is_fail)
+{
+  vl_api_connect_uri_reply_t *mp;
+  unix_shared_memory_queue_t *q;
+  application_t *app = application_lookup (api_client_index);
+  u8 *seg_name;
+  unix_shared_memory_queue_t *vpp_queue;
+
+  q = vl_api_client_index_to_input_queue (app->api_client_index);
+
+  if (!q)
+    return -1;
+
+  mp = vl_msg_api_alloc (sizeof (*mp));
+  mp->_vl_msg_id = clib_host_to_net_u16 (VL_API_CONNECT_URI_REPLY);
+  mp->context = app->api_context;
+  mp->retval = is_fail;
+  if (!is_fail)
+    {
+      vpp_queue = session_manager_get_vpp_event_queue (s->thread_index);
+      mp->server_rx_fifo = (u64) s->server_rx_fifo;
+      mp->server_tx_fifo = (u64) s->server_tx_fifo;
+      mp->session_thread_index = s->thread_index;
+      mp->session_index = s->session_index;
+      mp->session_type = s->session_type;
+      mp->vpp_event_queue_address = (u64) vpp_queue;
+      mp->client_event_queue_address = (u64) app->event_queue;
+
+      session_manager_get_segment_info (s->server_segment_index, &seg_name,
+					&mp->segment_size);
+      mp->segment_name_length = vec_len (seg_name);
+      if (mp->segment_name_length)
+	clib_memcpy (mp->segment_name, seg_name, mp->segment_name_length);
+    }
+
+  vl_msg_api_send_shmem (q, (u8 *) & mp);
+
+  /* Remove client if connect failed */
+  if (is_fail)
+    application_del (app);
+
+  return 0;
+}
+
+/**
+ * Redirect a connect_uri message to the indicated server.
+ * Only sent if the server has bound the related port with
+ * URI_OPTIONS_FLAGS_USE_FIFO
+ */
+static int
+redirect_connect_uri_callback (u32 server_api_client_index, void *mp_arg)
+{
+  vl_api_connect_uri_t *mp = mp_arg;
+  unix_shared_memory_queue_t *server_q, *client_q;
+  vlib_main_t *vm = vlib_get_main ();
+  f64 timeout = vlib_time_now (vm) + 0.5;
+  int rv = 0;
+
+  server_q = vl_api_client_index_to_input_queue (server_api_client_index);
+
+  if (!server_q)
+    {
+      rv = VNET_API_ERROR_INVALID_VALUE;
+      goto out;
+    }
+
+  client_q = vl_api_client_index_to_input_queue (mp->client_index);
+  if (!client_q)
+    {
+      rv = VNET_API_ERROR_INVALID_VALUE_2;
+      goto out;
+    }
+
+  /* Tell the server the client's API queue address, so it can reply */
+  mp->client_queue_address = (u64) client_q;
+
+  /*
+   * Bounce message handlers MUST NOT block the data-plane.
+   * Spin waiting for the queue lock, but
+   */
+
+  while (vlib_time_now (vm) < timeout)
+    {
+      rv =
+	unix_shared_memory_queue_add (server_q, (u8 *) & mp, 1 /*nowait */ );
+      switch (rv)
+	{
+	  /* correctly enqueued */
+	case 0:
+	  return VNET_CONNECT_REDIRECTED;
+
+	  /* continue spinning, wait for pthread_mutex_trylock to work */
+	case -1:
+	  continue;
+
+	  /* queue stuffed, drop the msg */
+	case -2:
+	  rv = VNET_API_ERROR_QUEUE_FULL;
+	  goto out;
+	}
+    }
+out:
+  /* Dispose of the message */
+  vl_msg_api_free (mp);
+  return rv;
+}
+
+static u64
+make_session_handle (stream_session_t * s)
+{
+  return (u64) s->session_index << 32 | (u64) s->thread_index;
+}
+
+static int
+send_session_accept_callback (stream_session_t * s)
+{
+  vl_api_accept_sock_t *mp;
+  unix_shared_memory_queue_t *q, *vpp_queue;
+  application_t *server = application_get (s->app_index);
+
+  q = vl_api_client_index_to_input_queue (server->api_client_index);
+  vpp_queue = session_manager_get_vpp_event_queue (s->thread_index);
+
+  if (!q)
+    return -1;
+
+  mp = vl_msg_api_alloc (sizeof (*mp));
+  mp->_vl_msg_id = clib_host_to_net_u16 (VL_API_ACCEPT_SOCK);
+
+  /* Note: session_type is the first octet in all types of sessions */
+
+  mp->accept_cookie = server->accept_cookie;
+  mp->server_rx_fifo = (u64) s->server_rx_fifo;
+  mp->server_tx_fifo = (u64) s->server_tx_fifo;
+  mp->handle = make_session_handle (s);
+  mp->vpp_event_queue_address = (u64) vpp_queue;
+  vl_msg_api_send_shmem (q, (u8 *) & mp);
+
+  return 0;
+}
+
+static int
+send_session_connected_callback (u32 api_client_index, stream_session_t * s,
+				 u8 is_fail)
+{
+  vl_api_connect_sock_reply_t *mp;
+  unix_shared_memory_queue_t *q;
+  application_t *app = application_lookup (api_client_index);
+  u8 *seg_name;
+  unix_shared_memory_queue_t *vpp_queue;
+
+  q = vl_api_client_index_to_input_queue (app->api_client_index);
+
+  if (!q)
+    return -1;
+
+  mp = vl_msg_api_alloc (sizeof (*mp));
+  mp->_vl_msg_id = clib_host_to_net_u16 (VL_API_CONNECT_SOCK_REPLY);
+  mp->context = app->api_context;
+  mp->retval = is_fail;
+  if (!is_fail)
+    {
+      vpp_queue = session_manager_get_vpp_event_queue (s->thread_index);
+      mp->server_rx_fifo = (u64) s->server_rx_fifo;
+      mp->server_tx_fifo = (u64) s->server_tx_fifo;
+      mp->handle = make_session_handle (s);
+      mp->vpp_event_queue_address = (u64) vpp_queue;
+      mp->client_event_queue_address = (u64) app->event_queue;
+
+      session_manager_get_segment_info (s->server_segment_index, &seg_name,
+					&mp->segment_size);
+      mp->segment_name_length = vec_len (seg_name);
+      if (mp->segment_name_length)
+	clib_memcpy (mp->segment_name, seg_name, mp->segment_name_length);
+    }
+
+  vl_msg_api_send_shmem (q, (u8 *) & mp);
+
+  /* Remove client if connect failed */
+  if (is_fail)
+    application_del (app);
+
+  return 0;
+}
+
+static void
+send_session_disconnect_callback (stream_session_t * s)
+{
+  vl_api_disconnect_sock_t *mp;
+  unix_shared_memory_queue_t *q;
+  application_t *app = application_get (s->app_index);
+
+  q = vl_api_client_index_to_input_queue (app->api_client_index);
+
+  if (!q)
+    return;
+
+  mp = vl_msg_api_alloc (sizeof (*mp));
+  memset (mp, 0, sizeof (*mp));
+  mp->_vl_msg_id = clib_host_to_net_u16 (VL_API_DISCONNECT_SOCK);
+
+  mp->handle = make_session_handle (s);
+  vl_msg_api_send_shmem (q, (u8 *) & mp);
+}
+
+/**
+ * Redirect a connect_uri message to the indicated server.
+ * Only sent if the server has bound the related port with
+ * URI_OPTIONS_FLAGS_USE_FIFO
+ */
+static int
+redirect_connect_callback (u32 server_api_client_index, void *mp_arg)
+{
+  vl_api_connect_sock_t *mp = mp_arg;
+  unix_shared_memory_queue_t *server_q, *client_q;
+  vlib_main_t *vm = vlib_get_main ();
+  f64 timeout = vlib_time_now (vm) + 0.5;
+  int rv = 0;
+
+  server_q = vl_api_client_index_to_input_queue (server_api_client_index);
+
+  if (!server_q)
+    {
+      rv = VNET_API_ERROR_INVALID_VALUE;
+      goto out;
+    }
+
+  client_q = vl_api_client_index_to_input_queue (mp->client_index);
+  if (!client_q)
+    {
+      rv = VNET_API_ERROR_INVALID_VALUE_2;
+      goto out;
+    }
+
+  /* Tell the server the client's API queue address, so it can reply */
+  mp->client_queue_address = (u64) client_q;
+
+  /*
+   * Bounce message handlers MUST NOT block the data-plane.
+   * Spin waiting for the queue lock, but
+   */
+
+  while (vlib_time_now (vm) < timeout)
+    {
+      rv =
+	unix_shared_memory_queue_add (server_q, (u8 *) & mp, 1 /*nowait */ );
+      switch (rv)
+	{
+	  /* correctly enqueued */
+	case 0:
+	  return VNET_CONNECT_REDIRECTED;
+
+	  /* continue spinning, wait for pthread_mutex_trylock to work */
+	case -1:
+	  continue;
+
+	  /* queue stuffed, drop the msg */
+	case -2:
+	  rv = VNET_API_ERROR_QUEUE_FULL;
+	  goto out;
+	}
+    }
+out:
+  /* Dispose of the message */
+  vl_msg_api_free (mp);
+  return rv;
+}
+
+static session_cb_vft_t uri_session_cb_vft = {
+  .session_accept_callback = send_session_accept_uri_callback,
+  .session_disconnect_callback = send_session_disconnect_uri_callback,
+  .session_connected_callback = send_session_connected_uri_callback,
+  .add_segment_callback = send_add_segment_callback,
+  .redirect_connect_callback = redirect_connect_uri_callback
+};
+
+static session_cb_vft_t session_cb_vft = {
+  .session_accept_callback = send_session_accept_callback,
+  .session_disconnect_callback = send_session_disconnect_callback,
+  .session_connected_callback = send_session_connected_callback,
+  .add_segment_callback = send_add_segment_callback,
+  .redirect_connect_callback = redirect_connect_callback
+};
+
+static int
+api_session_not_valid (u32 session_index, u32 thread_index)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  stream_session_t *pool;
+
+  if (thread_index >= vec_len (smm->sessions))
+    return VNET_API_ERROR_INVALID_VALUE;
+
+  pool = smm->sessions[thread_index];
+
+  if (pool_is_free_index (pool, session_index))
+    return VNET_API_ERROR_INVALID_VALUE_2;
+
+  return 0;
+}
+
+static void
+vl_api_bind_uri_t_handler (vl_api_bind_uri_t * mp)
+{
+  vl_api_bind_uri_reply_t *rmp;
+  vnet_bind_args_t _a, *a = &_a;
+  char segment_name[128];
+  u32 segment_name_length;
+  int rv;
+
+  _Static_assert (sizeof (u64) * SESSION_OPTIONS_N_OPTIONS <=
+		  sizeof (mp->options),
+		  "Out of options, fix api message definition");
+
+  segment_name_length = ARRAY_LEN (segment_name);
+
+  memset (a, 0, sizeof (*a));
+
+  a->uri = (char *) mp->uri;
+  a->api_client_index = mp->client_index;
+  a->options = mp->options;
+  a->segment_name = segment_name;
+  a->segment_name_length = segment_name_length;
+  a->session_cb_vft = &uri_session_cb_vft;
+
+  a->options[SESSION_OPTIONS_SEGMENT_SIZE] = mp->initial_segment_size;
+  a->options[SESSION_OPTIONS_ACCEPT_COOKIE] = mp->accept_cookie;
+  rv = vnet_bind_uri (a);
+
+  /* *INDENT-OFF* */
+  REPLY_MACRO2 (VL_API_BIND_URI_REPLY, ({
+    rmp->retval = rv;
+    if (!rv)
+      {
+	rmp->segment_name_length = 0;
+	/* $$$$ policy? */
+	rmp->segment_size = mp->initial_segment_size;
+	if (segment_name_length)
+	  {
+	    memcpy (rmp->segment_name, segment_name, segment_name_length);
+	    rmp->segment_name_length = segment_name_length;
+	  }
+	rmp->server_event_queue_address = a->server_event_queue_address;
+      }
+  }));
+  /* *INDENT-ON* */
+
+}
+
+static void
+vl_api_unbind_uri_t_handler (vl_api_unbind_uri_t * mp)
+{
+  vl_api_unbind_uri_reply_t *rmp;
+  int rv;
+
+  rv = vnet_unbind_uri ((char *) mp->uri, mp->client_index);
+
+  REPLY_MACRO (VL_API_UNBIND_URI_REPLY);
+}
+
+static void
+vl_api_connect_uri_t_handler (vl_api_connect_uri_t * mp)
+{
+  vnet_connect_args_t _a, *a = &_a;
+
+  a->uri = (char *) mp->uri;
+  a->api_client_index = mp->client_index;
+  a->api_context = mp->context;
+  a->options = mp->options;
+  a->session_cb_vft = &uri_session_cb_vft;
+  a->mp = mp;
+  vnet_connect_uri (a);
+}
+
+static void
+vl_api_disconnect_session_t_handler (vl_api_disconnect_session_t * mp)
+{
+  vl_api_disconnect_session_reply_t *rmp;
+  int rv;
+
+  rv = api_session_not_valid (mp->session_index, mp->session_thread_index);
+  if (!rv)
+    rv = vnet_disconnect_session (mp->client_index, mp->session_index,
+				  mp->session_thread_index);
+
+  REPLY_MACRO (VL_API_DISCONNECT_SESSION_REPLY);
+}
+
+static void
+vl_api_disconnect_session_reply_t_handler (vl_api_disconnect_session_reply_t *
+					   mp)
+{
+  if (api_session_not_valid (mp->session_index, mp->session_thread_index))
+    {
+      clib_warning ("Invalid session!");
+      return;
+    }
+
+  /* Client objected to disconnecting the session, log and continue */
+  if (mp->retval)
+    {
+      clib_warning ("client retval %d", mp->retval);
+      return;
+    }
+
+  /* Disconnect has been confirmed. Confirm close to transport */
+  vnet_disconnect_session (mp->client_index, mp->session_index,
+			   mp->session_thread_index);
+}
+
+static void
+vl_api_reset_session_reply_t_handler (vl_api_reset_session_reply_t * mp)
+{
+  stream_session_t *s;
+
+  if (api_session_not_valid (mp->session_index, mp->session_thread_index))
+    {
+      clib_warning ("Invalid session!");
+      return;
+    }
+
+  /* Client objected to resetting the session, log and continue */
+  if (mp->retval)
+    {
+      clib_warning ("client retval %d", mp->retval);
+      return;
+    }
+
+  s = stream_session_get (mp->session_index, mp->session_thread_index);
+
+  /* This comes as a response to a reset, transport only waiting for
+   * confirmation to remove connection state, no need to disconnect */
+  stream_session_cleanup (s);
+}
+
+static void
+vl_api_accept_session_reply_t_handler (vl_api_accept_session_reply_t * mp)
+{
+  stream_session_t *s;
+  int rv;
+
+  if (api_session_not_valid (mp->session_index, mp->session_thread_index))
+    return;
+
+  s = stream_session_get (mp->session_index, mp->session_thread_index);
+  rv = mp->retval;
+
+  if (rv)
+    {
+      /* Server isn't interested, kill the session */
+      stream_session_disconnect (s);
+      return;
+    }
+
+  s->session_state = SESSION_STATE_READY;
+}
+
+static void
+vl_api_map_another_segment_reply_t_handler (vl_api_map_another_segment_reply_t
+					    * mp)
+{
+  clib_warning ("not implemented");
+}
+
+static void
+vl_api_bind_sock_t_handler (vl_api_bind_sock_t * mp)
+{
+  vl_api_bind_sock_reply_t *rmp;
+  vnet_bind_args_t _a, *a = &_a;
+  char segment_name[128];
+  u32 segment_name_length;
+  int rv;
+
+  STATIC_ASSERT (sizeof (u64) * SESSION_OPTIONS_N_OPTIONS <=
+		 sizeof (mp->options),
+		 "Out of options, fix api message definition");
+
+  segment_name_length = ARRAY_LEN (segment_name);
+
+  memset (a, 0, sizeof (*a));
+
+  clib_memcpy (&a->tep.ip, mp->ip,
+	       (mp->is_ip4 ? sizeof (ip4_address_t) :
+		sizeof (ip6_address_t)));
+  a->tep.is_ip4 = mp->is_ip4;
+  a->tep.port = mp->port;
+  a->tep.vrf = mp->vrf;
+
+  a->api_client_index = mp->client_index;
+  a->options = mp->options;
+  a->segment_name = segment_name;
+  a->segment_name_length = segment_name_length;
+  a->session_cb_vft = &session_cb_vft;
+
+  rv = vnet_bind_uri (a);
+
+  /* *INDENT-OFF* */
+  REPLY_MACRO2 (VL_API_BIND_SOCK_REPLY, ({
+    rmp->retval = rv;
+    if (!rv)
+      {
+	rmp->segment_name_length = 0;
+	rmp->segment_size = mp->options[SESSION_OPTIONS_SEGMENT_SIZE];
+	if (segment_name_length)
+	  {
+	    memcpy(rmp->segment_name, segment_name, segment_name_length);
+	    rmp->segment_name_length = segment_name_length;
+	  }
+	rmp->server_event_queue_address = a->server_event_queue_address;
+      }
+  }));
+  /* *INDENT-ON* */
+}
+
+static void
+vl_api_unbind_sock_t_handler (vl_api_unbind_sock_t * mp)
+{
+  vl_api_unbind_sock_reply_t *rmp;
+  vnet_unbind_args_t _a, *a = &_a;
+  int rv;
+
+  a->api_client_index = mp->client_index;
+  a->handle = mp->handle;
+
+  rv = vnet_unbind (a);
+
+  REPLY_MACRO (VL_API_UNBIND_SOCK_REPLY);
+}
+
+static void
+vl_api_connect_sock_t_handler (vl_api_connect_sock_t * mp)
+{
+  vnet_connect_args_t _a, *a = &_a;
+
+  clib_memcpy (&a->tep.ip, mp->ip,
+	       (mp->is_ip4 ? sizeof (ip4_address_t) :
+		sizeof (ip6_address_t)));
+  a->tep.is_ip4 = mp->is_ip4;
+  a->tep.port = mp->port;
+  a->tep.vrf = mp->vrf;
+  a->options = mp->options;
+  a->session_cb_vft = &session_cb_vft;
+  a->api_context = mp->context;
+  a->mp = mp;
+
+  vnet_connect (a);
+}
+
+static void
+vl_api_disconnect_sock_t_handler (vl_api_disconnect_sock_t * mp)
+{
+  vnet_disconnect_args_t _a, *a = &_a;
+  vl_api_disconnect_sock_reply_t *rmp;
+  int rv;
+
+  a->api_client_index = mp->client_index;
+  a->handle = mp->handle;
+  rv = vnet_disconnect (a);
+
+  REPLY_MACRO (VL_API_DISCONNECT_SOCK_REPLY);
+}
+
+static void
+vl_api_disconnect_sock_reply_t_handler (vl_api_disconnect_sock_reply_t * mp)
+{
+  vnet_disconnect_args_t _a, *a = &_a;
+
+  /* Client objected to disconnecting the session, log and continue */
+  if (mp->retval)
+    {
+      clib_warning ("client retval %d", mp->retval);
+      return;
+    }
+
+  a->api_client_index = mp->client_index;
+  a->handle = mp->handle;
+
+  vnet_disconnect (a);
+}
+
+static void
+vl_api_reset_sock_reply_t_handler (vl_api_reset_sock_reply_t * mp)
+{
+  stream_session_t *s;
+  u32 session_index, thread_index;
+
+  /* Client objected to resetting the session, log and continue */
+  if (mp->retval)
+    {
+      clib_warning ("client retval %d", mp->retval);
+      return;
+    }
+
+  if (api_parse_session_handle (mp->handle, &session_index, &thread_index))
+    {
+      clib_warning ("Invalid handle");
+      return;
+    }
+
+  s = stream_session_get (session_index, thread_index);
+
+  /* This comes as a response to a reset, transport only waiting for
+   * confirmation to remove connection state, no need to disconnect */
+  stream_session_cleanup (s);
+}
+
+static void
+vl_api_accept_sock_reply_t_handler (vl_api_accept_sock_reply_t * mp)
+{
+  stream_session_t *s;
+  u32 session_index, thread_index;
+
+  if (api_parse_session_handle (mp->handle, &session_index, &thread_index))
+    {
+      clib_warning ("Invalid handle");
+      return;
+    }
+  s = stream_session_get (session_index, thread_index);
+
+  if (mp->retval)
+    {
+      /* Server isn't interested, kill the session */
+      stream_session_disconnect (s);
+      return;
+    }
+
+  s->session_state = SESSION_STATE_READY;
+}
+
+#define vl_msg_name_crc_list
+#include <vnet/vnet_all_api_h.h>
+#undef vl_msg_name_crc_list
+
+static void
+setup_message_id_table (api_main_t * am)
+{
+#define _(id,n,crc) vl_msg_api_add_msg_name_crc (am, #n "_" #crc, id);
+  foreach_vl_msg_name_crc_session;
+#undef _
+}
+
+/*
+ * session_api_hookup
+ * Add uri's API message handlers to the table.
+ * vlib has alread mapped shared memory and
+ * added the client registration handlers.
+ * See .../open-repo/vlib/memclnt_vlib.c:memclnt_process()
+ */
+static clib_error_t *
+session_api_hookup (vlib_main_t * vm)
+{
+  api_main_t *am = &api_main;
+
+#define _(N,n)                                                  \
+    vl_msg_api_set_handlers(VL_API_##N, #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_session_api_msg;
+#undef _
+
+  /*
+   * Messages which bounce off the data-plane to
+   * an API client. Simply tells the message handling infra not
+   * to free the message.
+   *
+   * Bounced message handlers MUST NOT block the data plane
+   */
+  am->message_bounce[VL_API_CONNECT_URI] = 1;
+  am->message_bounce[VL_API_CONNECT_SOCK] = 1;
+
+  /*
+   * Set up the (msg_name, crc, message-id) table
+   */
+  setup_message_id_table (am);
+
+  return 0;
+}
+
+VLIB_API_INIT_FUNCTION (session_api_hookup);
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/session_cli.c b/src/vnet/session/session_cli.c
new file mode 100644
index 00000000000..b2943a1ccc5
--- /dev/null
+++ b/src/vnet/session/session_cli.c
@@ -0,0 +1,189 @@
+/*
+ * Copyright (c) 2017 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 <vnet/session/application.h>
+#include <vnet/session/session.h>
+
+/**
+ * Format stream session as per the following format
+ *
+ * verbose:
+ *   "Connection", "Rx fifo", "Tx fifo", "Session Index"
+ * non-verbose:
+ *   "Connection"
+ */
+u8 *
+format_stream_session (u8 * s, va_list * args)
+{
+  stream_session_t *ss = va_arg (*args, stream_session_t *);
+  int verbose = va_arg (*args, int);
+  transport_proto_vft_t *tp_vft;
+  u8 *str = 0;
+
+  tp_vft = session_get_transport_vft (ss->session_type);
+
+  if (verbose)
+    str = format (0, "%-20llp%-20llp%-15lld", ss->server_rx_fifo,
+		  ss->server_tx_fifo, stream_session_get_index (ss));
+
+  if (ss->session_state == SESSION_STATE_READY)
+    {
+      s = format (s, "%-40U%v", tp_vft->format_connection,
+		  ss->connection_index, ss->thread_index, str);
+    }
+  else if (ss->session_state == SESSION_STATE_LISTENING)
+    {
+      s = format (s, "%-40U%v", tp_vft->format_listener, ss->connection_index,
+		  str);
+    }
+  else if (ss->session_state == SESSION_STATE_READY)
+    {
+      s =
+	format (s, "%-40U%v", tp_vft->format_half_open, ss->connection_index,
+		str);
+    }
+  else if (ss->session_state == SESSION_STATE_CLOSED)
+    {
+      s = format (s, "[CL] %-40U%v", tp_vft->format_connection,
+		  ss->connection_index, ss->thread_index, str);
+    }
+  else
+    {
+      clib_warning ("Session in unknown state!");
+    }
+
+  vec_free (str);
+
+  return s;
+}
+
+static clib_error_t *
+show_session_command_fn (vlib_main_t * vm, unformat_input_t * input,
+			 vlib_cli_command_t * cmd)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  int verbose = 0, i;
+  stream_session_t *pool;
+  stream_session_t *s;
+  u8 *str = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "verbose"))
+	verbose = 1;
+      else
+	break;
+    }
+
+  for (i = 0; i < vec_len (smm->sessions); i++)
+    {
+      u32 once_per_pool;
+      pool = smm->sessions[i];
+
+      once_per_pool = 1;
+
+      if (pool_elts (pool))
+	{
+
+	  vlib_cli_output (vm, "Thread %d: %d active sessions",
+			   i, pool_elts (pool));
+	  if (verbose)
+	    {
+	      if (once_per_pool)
+		{
+		  str = format (str, "%-40s%-20s%-20s%-15s",
+				"Connection", "Rx fifo", "Tx fifo",
+				"Session Index");
+		  vlib_cli_output (vm, "%v", str);
+		  vec_reset_length (str);
+		  once_per_pool = 0;
+		}
+
+              /* *INDENT-OFF* */
+              pool_foreach (s, pool,
+              ({
+                vlib_cli_output (vm, "%U", format_stream_session, s, verbose);
+              }));
+              /* *INDENT-ON* */
+	    }
+	}
+      else
+	vlib_cli_output (vm, "Thread %d: no active sessions", i);
+    }
+  vec_free (str);
+
+  return 0;
+}
+
+VLIB_CLI_COMMAND (show_uri_command, static) =
+{
+.path = "show session",.short_help = "show session [verbose]",.function =
+    show_session_command_fn,};
+
+
+static clib_error_t *
+clear_session_command_fn (vlib_main_t * vm, unformat_input_t * input,
+			  vlib_cli_command_t * cmd)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  u32 thread_index = 0;
+  u32 session_index = ~0;
+  stream_session_t *pool, *session;
+  application_t *server;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "thread %d", &thread_index))
+	;
+      else if (unformat (input, "session %d", &session_index))
+	;
+      else
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, input);
+    }
+
+  if (session_index == ~0)
+    return clib_error_return (0, "session <nn> required, but not set.");
+
+  if (thread_index > vec_len (smm->sessions))
+    return clib_error_return (0, "thread %d out of range [0-%d]",
+			      thread_index, vec_len (smm->sessions));
+
+  pool = smm->sessions[thread_index];
+
+  if (pool_is_free_index (pool, session_index))
+    return clib_error_return (0, "session %d not active", session_index);
+
+  session = pool_elt_at_index (pool, session_index);
+  server = application_get (session->app_index);
+
+  /* Disconnect both app and transport */
+  server->cb_fns.session_disconnect_callback (session);
+
+  return 0;
+}
+
+VLIB_CLI_COMMAND (clear_uri_session_command, static) =
+{
+.path = "clear session",.short_help =
+    "clear session thread <thread> session <index>",.function =
+    clear_session_command_fn,};
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/transport.c b/src/vnet/session/transport.c
new file mode 100644
index 00000000000..abd94ba4f1d
--- /dev/null
+++ b/src/vnet/session/transport.c
@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2017 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 <vnet/session/transport.h>
+
+u32
+transport_endpoint_lookup (transport_endpoint_table_t *ht, ip46_address_t *ip,
+                           u16 port)
+{
+  clib_bihash_kv_24_8_t kv;
+  int rv;
+
+  kv.key[0] = ip->as_u64[0];
+  kv.key[1] = ip->as_u64[1];
+  kv.key[2] = port;
+
+  rv = clib_bihash_search_inline_24_8 (ht, &kv);
+  if (rv == 0)
+    return kv.value;
+
+  return TRANSPORT_ENDPOINT_INVALID_INDEX;
+}
+
+void
+transport_endpoint_table_add (transport_endpoint_table_t *ht,
+                              transport_endpoint_t *te, u32 value)
+{
+  clib_bihash_kv_24_8_t kv;
+
+  kv.key[0] = te->ip.as_u64[0];
+  kv.key[1] = te->ip.as_u64[1];
+  kv.key[2] = te->port;
+  kv.value = value;
+
+  clib_bihash_add_del_24_8 (ht, &kv, 1);
+}
+
+void
+transport_endpoint_table_del (transport_endpoint_table_t *ht,
+                              transport_endpoint_t *te)
+{
+  clib_bihash_kv_24_8_t kv;
+
+  kv.key[0] = te->ip.as_u64[0];
+  kv.key[1] = te->ip.as_u64[1];
+  kv.key[2] = te->port;
+
+  clib_bihash_add_del_24_8 (ht, &kv, 0);
+}
+
+
+
diff --git a/src/vnet/session/transport.h b/src/vnet/session/transport.h
new file mode 100644
index 00000000000..2d4415ba6a3
--- /dev/null
+++ b/src/vnet/session/transport.h
@@ -0,0 +1,250 @@
+/*
+ * Copyright (c) 2016 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 VNET_VNET_URI_TRANSPORT_H_
+#define VNET_VNET_URI_TRANSPORT_H_
+
+#include <vnet/vnet.h>
+#include <vnet/ip/ip.h>
+#include <vppinfra/bihash_16_8.h>
+#include <vppinfra/bihash_48_8.h>
+
+/*
+ * Protocol independent transport properties associated to a session
+ */
+typedef struct _transport_connection
+{
+  ip46_address_t rmt_ip;	/**< Remote IP */
+  ip46_address_t lcl_ip;	/**< Local IP */
+  u16 lcl_port;			/**< Local port */
+  u16 rmt_port;			/**< Remote port */
+  u8 proto;			/**< Transport protocol id */
+
+  u32 s_index;			/**< Parent session index */
+  u32 c_index;			/**< Connection index in transport pool */
+  u8 is_ip4;			/**< Flag if IP4 connection */
+  u32 thread_index;		/**< Worker-thread index */
+
+  /** Macros for 'derived classes' where base is named "connection" */
+#define c_lcl_ip connection.lcl_ip
+#define c_rmt_ip connection.rmt_ip
+#define c_lcl_ip4 connection.lcl_ip.ip4
+#define c_rmt_ip4 connection.rmt_ip.ip4
+#define c_lcl_ip6 connection.lcl_ip.ip6
+#define c_rmt_ip6 connection.rmt_ip.ip6
+#define c_lcl_port connection.lcl_port
+#define c_rmt_port connection.rmt_port
+#define c_proto connection.proto
+#define c_state connection.state
+#define c_s_index connection.s_index
+#define c_c_index connection.c_index
+#define c_is_ip4 connection.is_ip4
+#define c_thread_index connection.thread_index
+} transport_connection_t;
+
+/*
+ * Transport protocol virtual function table
+ */
+typedef struct _transport_proto_vft
+{
+  /*
+   * Setup
+   */
+  u32 (*bind) (vlib_main_t *, u32, ip46_address_t *, u16);
+  u32 (*unbind) (vlib_main_t *, u32);
+  int (*open) (ip46_address_t * addr, u16 port_host_byte_order);
+  void (*close) (u32 conn_index, u32 thread_index);
+  void (*cleanup) (u32 conn_index, u32 thread_index);
+
+  /*
+   * Transmission
+   */
+    u32 (*push_header) (transport_connection_t * tconn, vlib_buffer_t * b);
+    u16 (*send_mss) (transport_connection_t * tc);
+    u32 (*send_space) (transport_connection_t * tc);
+    u32 (*rx_fifo_offset) (transport_connection_t * tc);
+
+  /*
+   * Connection retrieval
+   */
+  transport_connection_t *(*get_connection) (u32 conn_idx, u32 thread_idx);
+  transport_connection_t *(*get_listener) (u32 conn_index);
+  transport_connection_t *(*get_half_open) (u32 conn_index);
+
+  /*
+   * Format
+   */
+  u8 *(*format_connection) (u8 * s, va_list * args);
+  u8 *(*format_listener) (u8 * s, va_list * args);
+  u8 *(*format_half_open) (u8 * s, va_list * args);
+
+} transport_proto_vft_t;
+
+/* 16 octets */
+typedef CLIB_PACKED (struct
+		     {
+		     union
+		     {
+		     struct
+		     {
+		     ip4_address_t src; ip4_address_t dst;
+		     u16 src_port;
+		     u16 dst_port;
+		     /* align by making this 4 octets even though its a 1-bit field
+		      * NOTE: avoid key overlap with other transports that use 5 tuples for
+		      * session identification.
+		      */
+		     u32 proto;
+		     };
+		     u64 as_u64[2];
+		     };
+		     }) v4_connection_key_t;
+
+typedef CLIB_PACKED (struct
+		     {
+		     union
+		     {
+		     struct
+		     {
+		     /* 48 octets */
+		     ip6_address_t src; ip6_address_t dst;
+		     u16 src_port;
+		     u16 dst_port; u32 proto; u8 unused_for_now[8];
+		     }; u64 as_u64[6];
+		     };
+		     }) v6_connection_key_t;
+
+typedef clib_bihash_kv_16_8_t session_kv4_t;
+typedef clib_bihash_kv_48_8_t session_kv6_t;
+
+always_inline void
+make_v4_ss_kv (session_kv4_t * kv, ip4_address_t * lcl, ip4_address_t * rmt,
+	       u16 lcl_port, u16 rmt_port, u8 proto)
+{
+  v4_connection_key_t key;
+  memset (&key, 0, sizeof (v4_connection_key_t));
+
+  key.src.as_u32 = lcl->as_u32;
+  key.dst.as_u32 = rmt->as_u32;
+  key.src_port = lcl_port;
+  key.dst_port = rmt_port;
+  key.proto = proto;
+
+  kv->key[0] = key.as_u64[0];
+  kv->key[1] = key.as_u64[1];
+  kv->value = ~0ULL;
+}
+
+always_inline void
+make_v4_listener_kv (session_kv4_t * kv, ip4_address_t * lcl, u16 lcl_port,
+		     u8 proto)
+{
+  v4_connection_key_t key;
+  memset (&key, 0, sizeof (v4_connection_key_t));
+
+  key.src.as_u32 = lcl->as_u32;
+  key.dst.as_u32 = 0;
+  key.src_port = lcl_port;
+  key.dst_port = 0;
+  key.proto = proto;
+
+  kv->key[0] = key.as_u64[0];
+  kv->key[1] = key.as_u64[1];
+  kv->value = ~0ULL;
+}
+
+always_inline void
+make_v4_ss_kv_from_tc (session_kv4_t * kv, transport_connection_t * t)
+{
+  return make_v4_ss_kv (kv, &t->lcl_ip.ip4, &t->rmt_ip.ip4, t->lcl_port,
+			t->rmt_port, t->proto);
+}
+
+always_inline void
+make_v6_ss_kv (session_kv6_t * kv, ip6_address_t * lcl, ip6_address_t * rmt,
+	       u16 lcl_port, u16 rmt_port, u8 proto)
+{
+  v6_connection_key_t key;
+  memset (&key, 0, sizeof (v6_connection_key_t));
+
+  key.src.as_u64[0] = lcl->as_u64[0];
+  key.src.as_u64[1] = lcl->as_u64[1];
+  key.dst.as_u64[0] = rmt->as_u64[0];
+  key.dst.as_u64[1] = rmt->as_u64[1];
+  key.src_port = lcl_port;
+  key.dst_port = rmt_port;
+  key.proto = proto;
+
+  kv->key[0] = key.as_u64[0];
+  kv->key[1] = key.as_u64[1];
+  kv->value = ~0ULL;
+}
+
+always_inline void
+make_v6_listener_kv (session_kv6_t * kv, ip6_address_t * lcl, u16 lcl_port,
+		     u8 proto)
+{
+  v6_connection_key_t key;
+  memset (&key, 0, sizeof (v6_connection_key_t));
+
+  key.src.as_u64[0] = lcl->as_u64[0];
+  key.src.as_u64[1] = lcl->as_u64[1];
+  key.dst.as_u64[0] = 0;
+  key.dst.as_u64[1] = 0;
+  key.src_port = lcl_port;
+  key.dst_port = 0;
+  key.proto = proto;
+
+  kv->key[0] = key.as_u64[0];
+  kv->key[1] = key.as_u64[1];
+  kv->value = ~0ULL;
+}
+
+always_inline void
+make_v6_ss_kv_from_tc (session_kv6_t * kv, transport_connection_t * t)
+{
+  make_v6_ss_kv (kv, &t->lcl_ip.ip6, &t->rmt_ip.ip6, t->lcl_port,
+		 t->rmt_port, t->proto);
+}
+
+typedef struct _transport_endpoint
+{
+  ip46_address_t ip;
+  u16 port;
+  u8 is_ip4;
+  u32 vrf;
+} transport_endpoint_t;
+
+typedef clib_bihash_24_8_t transport_endpoint_table_t;
+
+#define TRANSPORT_ENDPOINT_INVALID_INDEX ((u32)~0)
+
+u32
+transport_endpoint_lookup (transport_endpoint_table_t * ht,
+			   ip46_address_t * ip, u16 port);
+void transport_endpoint_table_add (transport_endpoint_table_t * ht,
+				   transport_endpoint_t * te, u32 value);
+void transport_endpoint_table_del (transport_endpoint_table_t * ht,
+				   transport_endpoint_t * te);
+
+#endif /* VNET_VNET_URI_TRANSPORT_H_ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */