NAT: Refactoring / Housekeeping (VPP-1415)

Change-Id: Ia3ce24cc94f9b2fb331ad62a4181ddcd41bc78ca
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 934 insertions, 0 deletions

diff --git a/src/plugins/nat/nat44_hairpinning.c b/src/plugins/nat/nat44_hairpinning.c
new file mode 100644
index 00000000000..9d49dc2300e
--- /dev/null
+++ b/src/plugins/nat/nat44_hairpinning.c
@@ -0,0 +1,934 @@
+/*
+ * Copyright (c) 2018 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 NAT44 hairpinning
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/fib/ip4_fib.h>
+#include <nat/nat.h>
+#include <nat/nat_inlines.h>
+#include <nat/nat_reass.h>
+
+typedef enum
+{
+  SNAT_HAIRPIN_SRC_NEXT_DROP,
+  SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT,
+  SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT_WH,
+  SNAT_HAIRPIN_SRC_NEXT_INTERFACE_OUTPUT,
+  SNAT_HAIRPIN_SRC_N_NEXT,
+} snat_hairpin_src_next_t;
+
+typedef enum
+{
+  NAT_HAIRPIN_NEXT_LOOKUP,
+  NAT_HAIRPIN_NEXT_DROP,
+  NAT_HAIRPIN_N_NEXT,
+} nat_hairpin_next_t;
+
+#define foreach_nat44_hairpin_error                       \
+_(PROCESSED, "NAT44 hairpinning packets processed")
+
+typedef enum
+{
+#define _(sym,str) NAT44_HAIRPIN_ERROR_##sym,
+  foreach_nat44_hairpin_error
+#undef _
+    NAT44_HAIRPIN_N_ERROR,
+} nat44_hairpin_error_t;
+
+static char *nat44_hairpin_error_strings[] = {
+#define _(sym,string) string,
+  foreach_nat44_hairpin_error
+#undef _
+};
+
+vlib_node_registration_t snat_hairpin_dst_node;
+vlib_node_registration_t snat_hairpin_src_node;
+vlib_node_registration_t nat44_hairpinning_node;
+vlib_node_registration_t nat44_ed_hairpin_dst_node;
+vlib_node_registration_t nat44_ed_hairpin_src_node;
+vlib_node_registration_t nat44_ed_hairpinning_node;
+
+extern vnet_feature_arc_registration_t vnet_feat_arc_ip4_local;
+
+static_always_inline int
+is_hairpinning (snat_main_t * sm, ip4_address_t * dst_addr)
+{
+  snat_address_t *ap;
+  clib_bihash_kv_8_8_t kv, value;
+  snat_session_key_t m_key;
+
+  /* *INDENT-OFF* */
+  vec_foreach (ap, sm->addresses)
+    {
+      if (ap->addr.as_u32 == dst_addr->as_u32)
+        return 1;
+    }
+  /* *INDENT-ON* */
+
+  m_key.addr.as_u32 = dst_addr->as_u32;
+  m_key.fib_index = 0;
+  m_key.port = 0;
+  m_key.protocol = 0;
+  kv.key = m_key.as_u64;
+  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+    return 1;
+
+  return 0;
+}
+
+int
+snat_hairpinning (snat_main_t * sm,
+		  vlib_buffer_t * b0,
+		  ip4_header_t * ip0,
+		  udp_header_t * udp0,
+		  tcp_header_t * tcp0, u32 proto0, int is_ed)
+{
+  snat_session_key_t key0, sm0;
+  snat_session_t *s0;
+  clib_bihash_kv_8_8_t kv0, value0;
+  ip_csum_t sum0;
+  u32 new_dst_addr0 = 0, old_dst_addr0, ti = 0, si;
+  u16 new_dst_port0, old_dst_port0;
+  int rv;
+
+  key0.addr = ip0->dst_address;
+  key0.port = udp0->dst_port;
+  key0.protocol = proto0;
+  key0.fib_index = sm->outside_fib_index;
+  kv0.key = key0.as_u64;
+
+  /* Check if destination is static mappings */
+  if (!snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0))
+    {
+      new_dst_addr0 = sm0.addr.as_u32;
+      new_dst_port0 = sm0.port;
+      vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
+    }
+  /* or active session */
+  else
+    {
+      if (sm->num_workers > 1)
+	ti =
+	  (clib_net_to_host_u16 (udp0->dst_port) -
+	   1024) / sm->port_per_thread;
+      else
+	ti = sm->num_workers;
+
+      if (is_ed)
+	{
+	  clib_bihash_kv_16_8_t ed_kv, ed_value;
+	  make_ed_kv (&ed_kv, &ip0->dst_address, &ip0->src_address,
+		      ip0->protocol, sm->outside_fib_index, udp0->dst_port,
+		      udp0->src_port);
+	  rv = clib_bihash_search_16_8 (&sm->per_thread_data[ti].out2in_ed,
+					&ed_kv, &ed_value);
+	  si = ed_value.value;
+	}
+      else
+	{
+	  rv = clib_bihash_search_8_8 (&sm->per_thread_data[ti].out2in, &kv0,
+				       &value0);
+	  si = value0.value;
+	}
+      if (rv)
+	return 0;
+
+      s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
+      new_dst_addr0 = s0->in2out.addr.as_u32;
+      new_dst_port0 = s0->in2out.port;
+      vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+    }
+
+  /* Destination is behind the same NAT, use internal address and port */
+  if (new_dst_addr0)
+    {
+      old_dst_addr0 = ip0->dst_address.as_u32;
+      ip0->dst_address.as_u32 = new_dst_addr0;
+      sum0 = ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
+			     ip4_header_t, dst_address);
+      ip0->checksum = ip_csum_fold (sum0);
+
+      old_dst_port0 = tcp0->dst;
+      if (PREDICT_TRUE (new_dst_port0 != old_dst_port0))
+	{
+	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+	    {
+	      tcp0->dst = new_dst_port0;
+	      sum0 = tcp0->checksum;
+	      sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
+				     ip4_header_t, dst_address);
+	      sum0 = ip_csum_update (sum0, old_dst_port0, new_dst_port0,
+				     ip4_header_t /* cheat */ , length);
+	      tcp0->checksum = ip_csum_fold (sum0);
+	    }
+	  else
+	    {
+	      udp0->dst_port = new_dst_port0;
+	      udp0->checksum = 0;
+	    }
+	}
+      else
+	{
+	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+	    {
+	      sum0 = tcp0->checksum;
+	      sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
+				     ip4_header_t, dst_address);
+	      tcp0->checksum = ip_csum_fold (sum0);
+	    }
+	}
+      return 1;
+    }
+  return 0;
+}
+
+u32
+snat_icmp_hairpinning (snat_main_t * sm,
+		       vlib_buffer_t * b0,
+		       ip4_header_t * ip0, icmp46_header_t * icmp0, int is_ed)
+{
+  snat_session_key_t key0;
+  clib_bihash_kv_8_8_t kv0, value0;
+  u32 old_dst_addr0, new_dst_addr0;
+  u32 old_addr0, new_addr0;
+  u16 old_port0, new_port0;
+  u16 old_checksum0, new_checksum0;
+  u32 si, ti = 0;
+  ip_csum_t sum0;
+  snat_session_t *s0;
+  snat_static_mapping_t *m0;
+
+  if (icmp_is_error_message (icmp0))
+    {
+      ip4_header_t *inner_ip0 = 0;
+      tcp_udp_header_t *l4_header = 0;
+
+      inner_ip0 = (ip4_header_t *) ((icmp_echo_header_t *) (icmp0 + 1) + 1);
+      l4_header = ip4_next_header (inner_ip0);
+      u32 protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
+
+      if (protocol != SNAT_PROTOCOL_TCP && protocol != SNAT_PROTOCOL_UDP)
+	return 1;
+
+      if (is_ed)
+	{
+	  clib_bihash_kv_16_8_t ed_kv, ed_value;
+	  make_ed_kv (&ed_kv, &ip0->dst_address, &ip0->src_address,
+		      inner_ip0->protocol, sm->outside_fib_index,
+		      l4_header->src_port, l4_header->dst_port);
+	  if (clib_bihash_search_16_8 (&sm->per_thread_data[ti].out2in_ed,
+				       &ed_kv, &ed_value))
+	    return 1;
+	  si = ed_value.value;
+	}
+      else
+	{
+	  key0.addr = ip0->dst_address;
+	  key0.port = l4_header->src_port;
+	  key0.protocol = protocol;
+	  key0.fib_index = sm->outside_fib_index;
+	  kv0.key = key0.as_u64;
+	  if (clib_bihash_search_8_8 (&sm->per_thread_data[ti].out2in, &kv0,
+				      &value0))
+	    return 1;
+	  si = value0.value;
+	}
+      s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
+      new_dst_addr0 = s0->in2out.addr.as_u32;
+      vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+
+      /* update inner source IP address */
+      old_addr0 = inner_ip0->src_address.as_u32;
+      inner_ip0->src_address.as_u32 = new_dst_addr0;
+      new_addr0 = inner_ip0->src_address.as_u32;
+      sum0 = icmp0->checksum;
+      sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+			     src_address);
+      icmp0->checksum = ip_csum_fold (sum0);
+
+      /* update inner IP header checksum */
+      old_checksum0 = inner_ip0->checksum;
+      sum0 = inner_ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+			     src_address);
+      inner_ip0->checksum = ip_csum_fold (sum0);
+      new_checksum0 = inner_ip0->checksum;
+      sum0 = icmp0->checksum;
+      sum0 = ip_csum_update (sum0, old_checksum0, new_checksum0, ip4_header_t,
+			     checksum);
+      icmp0->checksum = ip_csum_fold (sum0);
+
+      /* update inner source port */
+      old_port0 = l4_header->src_port;
+      l4_header->src_port = s0->in2out.port;
+      new_port0 = l4_header->src_port;
+      sum0 = icmp0->checksum;
+      sum0 = ip_csum_update (sum0, old_port0, new_port0, tcp_udp_header_t,
+			     src_port);
+      icmp0->checksum = ip_csum_fold (sum0);
+    }
+  else
+    {
+      if (!is_ed)
+	{
+	  icmp_echo_header_t *echo0 = (icmp_echo_header_t *) (icmp0 + 1);
+	  u16 icmp_id0 = echo0->identifier;
+	  key0.addr = ip0->dst_address;
+	  key0.port = icmp_id0;
+	  key0.protocol = SNAT_PROTOCOL_ICMP;
+	  key0.fib_index = sm->outside_fib_index;
+	  kv0.key = key0.as_u64;
+	  if (sm->num_workers > 1)
+	    ti =
+	      (clib_net_to_host_u16 (icmp_id0) - 1024) / sm->port_per_thread;
+	  else
+	    ti = sm->num_workers;
+	  int rv =
+	    clib_bihash_search_8_8 (&sm->per_thread_data[ti].out2in, &kv0,
+				    &value0);
+	  if (!rv)
+	    {
+	      si = value0.value;
+	      s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
+	      new_dst_addr0 = s0->in2out.addr.as_u32;
+	      vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+	      echo0->identifier = s0->in2out.port;
+	      sum0 = icmp0->checksum;
+	      sum0 = ip_csum_update (sum0, icmp_id0, s0->in2out.port,
+				     icmp_echo_header_t, identifier);
+	      icmp0->checksum = ip_csum_fold (sum0);
+	      goto change_addr;
+	    }
+	  ti = 0;
+	}
+
+      key0.addr = ip0->dst_address;
+      key0.port = 0;
+      key0.protocol = 0;
+      key0.fib_index = sm->outside_fib_index;
+      kv0.key = key0.as_u64;
+
+      if (clib_bihash_search_8_8
+	  (&sm->static_mapping_by_external, &kv0, &value0))
+	return 1;
+
+      m0 = pool_elt_at_index (sm->static_mappings, value0.value);
+
+      new_dst_addr0 = m0->local_addr.as_u32;
+      if (vnet_buffer (b0)->sw_if_index[VLIB_TX] == ~0)
+	vnet_buffer (b0)->sw_if_index[VLIB_TX] = m0->fib_index;
+    }
+change_addr:
+  /* Destination is behind the same NAT, use internal address and port */
+  if (new_dst_addr0)
+    {
+      old_dst_addr0 = ip0->dst_address.as_u32;
+      ip0->dst_address.as_u32 = new_dst_addr0;
+      sum0 = ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
+			     ip4_header_t, dst_address);
+      ip0->checksum = ip_csum_fold (sum0);
+    }
+  return 0;
+}
+
+void
+nat_hairpinning_sm_unknown_proto (snat_main_t * sm,
+				  vlib_buffer_t * b, ip4_header_t * ip)
+{
+  clib_bihash_kv_8_8_t kv, value;
+  snat_static_mapping_t *m;
+  u32 old_addr, new_addr;
+  ip_csum_t sum;
+
+  make_sm_kv (&kv, &ip->dst_address, 0, 0, 0);
+  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+    return;
+
+  m = pool_elt_at_index (sm->static_mappings, value.value);
+
+  old_addr = ip->dst_address.as_u32;
+  new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
+  sum = ip->checksum;
+  sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
+  ip->checksum = ip_csum_fold (sum);
+
+  if (vnet_buffer (b)->sw_if_index[VLIB_TX] == ~0)
+    vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
+}
+
+void
+nat44_ed_hairpinning_unknown_proto (snat_main_t * sm,
+				    vlib_buffer_t * b, ip4_header_t * ip)
+{
+  u32 old_addr, new_addr = 0, ti = 0;
+  clib_bihash_kv_8_8_t kv, value;
+  clib_bihash_kv_16_8_t s_kv, s_value;
+  snat_static_mapping_t *m;
+  ip_csum_t sum;
+  snat_session_t *s;
+  snat_main_per_thread_data_t *tsm;
+
+  if (sm->num_workers > 1)
+    ti = sm->worker_out2in_cb (ip, sm->outside_fib_index);
+  else
+    ti = sm->num_workers;
+  tsm = &sm->per_thread_data[ti];
+
+  old_addr = ip->dst_address.as_u32;
+  make_ed_kv (&s_kv, &ip->dst_address, &ip->src_address, ip->protocol,
+	      sm->outside_fib_index, 0, 0);
+  if (clib_bihash_search_16_8 (&tsm->out2in_ed, &s_kv, &s_value))
+    {
+      make_sm_kv (&kv, &ip->dst_address, 0, 0, 0);
+      if (clib_bihash_search_8_8
+	  (&sm->static_mapping_by_external, &kv, &value))
+	return;
+
+      m = pool_elt_at_index (sm->static_mappings, value.value);
+      if (vnet_buffer (b)->sw_if_index[VLIB_TX] == ~0)
+	vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
+      new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
+    }
+  else
+    {
+      s = pool_elt_at_index (sm->per_thread_data[ti].sessions, s_value.value);
+      if (vnet_buffer (b)->sw_if_index[VLIB_TX] == ~0)
+	vnet_buffer (b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
+      new_addr = ip->dst_address.as_u32 = s->in2out.addr.as_u32;
+    }
+  sum = ip->checksum;
+  sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
+  ip->checksum = ip_csum_fold (sum);
+}
+
+void
+nat44_reass_hairpinning (snat_main_t * sm,
+			 vlib_buffer_t * b0,
+			 ip4_header_t * ip0,
+			 u16 sport, u16 dport, u32 proto0, int is_ed)
+{
+  snat_session_key_t key0, sm0;
+  snat_session_t *s0;
+  clib_bihash_kv_8_8_t kv0, value0;
+  ip_csum_t sum0;
+  u32 new_dst_addr0 = 0, old_dst_addr0, ti = 0, si;
+  u16 new_dst_port0, old_dst_port0;
+  udp_header_t *udp0;
+  tcp_header_t *tcp0;
+  int rv;
+
+  key0.addr = ip0->dst_address;
+  key0.port = dport;
+  key0.protocol = proto0;
+  key0.fib_index = sm->outside_fib_index;
+  kv0.key = key0.as_u64;
+
+  udp0 = ip4_next_header (ip0);
+
+  /* Check if destination is static mappings */
+  if (!snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0))
+    {
+      new_dst_addr0 = sm0.addr.as_u32;
+      new_dst_port0 = sm0.port;
+      vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
+    }
+  /* or active sessions */
+  else
+    {
+      if (sm->num_workers > 1)
+	ti =
+	  (clib_net_to_host_u16 (udp0->dst_port) -
+	   1024) / sm->port_per_thread;
+      else
+	ti = sm->num_workers;
+
+      if (is_ed)
+	{
+	  clib_bihash_kv_16_8_t ed_kv, ed_value;
+	  make_ed_kv (&ed_kv, &ip0->dst_address, &ip0->src_address,
+		      ip0->protocol, sm->outside_fib_index, udp0->dst_port,
+		      udp0->src_port);
+	  rv = clib_bihash_search_16_8 (&sm->per_thread_data[ti].out2in_ed,
+					&ed_kv, &ed_value);
+	  si = ed_value.value;
+	}
+      else
+	{
+	  rv = clib_bihash_search_8_8 (&sm->per_thread_data[ti].out2in, &kv0,
+				       &value0);
+	  si = value0.value;
+	}
+      if (!rv)
+	{
+	  s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
+	  new_dst_addr0 = s0->in2out.addr.as_u32;
+	  new_dst_port0 = s0->in2out.port;
+	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+	}
+    }
+
+  /* Destination is behind the same NAT, use internal address and port */
+  if (new_dst_addr0)
+    {
+      old_dst_addr0 = ip0->dst_address.as_u32;
+      ip0->dst_address.as_u32 = new_dst_addr0;
+      sum0 = ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
+			     ip4_header_t, dst_address);
+      ip0->checksum = ip_csum_fold (sum0);
+
+      old_dst_port0 = dport;
+      if (PREDICT_TRUE (new_dst_port0 != old_dst_port0 &&
+			ip4_is_first_fragment (ip0)))
+	{
+	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+	    {
+	      tcp0 = ip4_next_header (ip0);
+	      tcp0->dst = new_dst_port0;
+	      sum0 = tcp0->checksum;
+	      sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
+				     ip4_header_t, dst_address);
+	      sum0 = ip_csum_update (sum0, old_dst_port0, new_dst_port0,
+				     ip4_header_t /* cheat */ , length);
+	      tcp0->checksum = ip_csum_fold (sum0);
+	    }
+	  else
+	    {
+	      udp0->dst_port = new_dst_port0;
+	      udp0->checksum = 0;
+	    }
+	}
+      else
+	{
+	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+	    {
+	      tcp0 = ip4_next_header (ip0);
+	      sum0 = tcp0->checksum;
+	      sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
+				     ip4_header_t, dst_address);
+	      tcp0->checksum = ip_csum_fold (sum0);
+	    }
+	}
+    }
+}
+
+static inline uword
+nat44_hairpinning_fn_inline (vlib_main_t * vm,
+			     vlib_node_runtime_t * node,
+			     vlib_frame_t * frame, int is_ed)
+{
+  u32 n_left_from, *from, *to_next, stats_node_index;
+  nat_hairpin_next_t next_index;
+  u32 pkts_processed = 0;
+  snat_main_t *sm = &snat_main;
+  vnet_feature_main_t *fm = &feature_main;
+  u8 arc_index = vnet_feat_arc_ip4_local.feature_arc_index;
+  vnet_feature_config_main_t *cm = &fm->feature_config_mains[arc_index];
+
+  stats_node_index = is_ed ? nat44_ed_hairpinning_node.index :
+    nat44_hairpinning_node.index;
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0;
+	  ip4_header_t *ip0;
+	  u32 proto0;
+	  udp_header_t *udp0;
+	  tcp_header_t *tcp0;
+
+	  /* speculatively enqueue b0 to the current next frame */
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  ip0 = vlib_buffer_get_current (b0);
+	  udp0 = ip4_next_header (ip0);
+	  tcp0 = (tcp_header_t *) udp0;
+
+	  proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+	  vnet_get_config_data (&cm->config_main, &b0->current_config_index,
+				&next0, 0);
+
+	  if (snat_hairpinning (sm, b0, ip0, udp0, tcp0, proto0, is_ed))
+	    next0 = NAT_HAIRPIN_NEXT_LOOKUP;
+
+	  pkts_processed += next0 != NAT_HAIRPIN_NEXT_DROP;
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  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);
+    }
+
+  vlib_node_increment_counter (vm, stats_node_index,
+			       NAT44_HAIRPIN_ERROR_PROCESSED, pkts_processed);
+  return frame->n_vectors;
+}
+
+static uword
+nat44_hairpinning_fn (vlib_main_t * vm,
+		      vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return nat44_hairpinning_fn_inline (vm, node, frame, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_hairpinning_node) = {
+  .function = nat44_hairpinning_fn,
+  .name = "nat44-hairpinning",
+  .vector_size = sizeof (u32),
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .error_strings = nat44_hairpin_error_strings,
+  .n_next_nodes = NAT_HAIRPIN_N_NEXT,
+  .next_nodes = {
+    [NAT_HAIRPIN_NEXT_DROP] = "error-drop",
+    [NAT_HAIRPIN_NEXT_LOOKUP] = "ip4-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_hairpinning_node, nat44_hairpinning_fn);
+
+static uword
+nat44_ed_hairpinning_fn (vlib_main_t * vm,
+			 vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return nat44_hairpinning_fn_inline (vm, node, frame, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_hairpinning_node) = {
+  .function = nat44_ed_hairpinning_fn,
+  .name = "nat44-ed-hairpinning",
+  .vector_size = sizeof (u32),
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .error_strings = nat44_hairpin_error_strings,
+  .n_next_nodes = NAT_HAIRPIN_N_NEXT,
+  .next_nodes = {
+    [NAT_HAIRPIN_NEXT_DROP] = "error-drop",
+    [NAT_HAIRPIN_NEXT_LOOKUP] = "ip4-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_hairpinning_node,
+			      nat44_ed_hairpinning_fn);
+
+static inline uword
+snat_hairpin_dst_fn_inline (vlib_main_t * vm,
+			    vlib_node_runtime_t * node,
+			    vlib_frame_t * frame, int is_ed)
+{
+  u32 n_left_from, *from, *to_next, stats_node_index;
+  nat_hairpin_next_t next_index;
+  u32 pkts_processed = 0;
+  snat_main_t *sm = &snat_main;
+
+  stats_node_index = is_ed ? nat44_ed_hairpin_dst_node.index :
+    snat_hairpin_dst_node.index;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0;
+	  ip4_header_t *ip0;
+	  u32 proto0;
+
+	  /* speculatively enqueue b0 to the current next frame */
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  next0 = NAT_HAIRPIN_NEXT_LOOKUP;
+	  ip0 = vlib_buffer_get_current (b0);
+
+	  proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+	  vnet_buffer (b0)->snat.flags = 0;
+	  if (PREDICT_FALSE (is_hairpinning (sm, &ip0->dst_address)))
+	    {
+	      if (proto0 == SNAT_PROTOCOL_TCP || proto0 == SNAT_PROTOCOL_UDP)
+		{
+		  udp_header_t *udp0 = ip4_next_header (ip0);
+		  tcp_header_t *tcp0 = (tcp_header_t *) udp0;
+
+		  snat_hairpinning (sm, b0, ip0, udp0, tcp0, proto0, is_ed);
+		}
+	      else if (proto0 == SNAT_PROTOCOL_ICMP)
+		{
+		  icmp46_header_t *icmp0 = ip4_next_header (ip0);
+
+		  snat_icmp_hairpinning (sm, b0, ip0, icmp0, is_ed);
+		}
+	      else
+		{
+		  if (is_ed)
+		    nat44_ed_hairpinning_unknown_proto (sm, b0, ip0);
+		  else
+		    nat_hairpinning_sm_unknown_proto (sm, b0, ip0);
+		}
+
+	      vnet_buffer (b0)->snat.flags = SNAT_FLAG_HAIRPINNING;
+	    }
+
+	  pkts_processed += next0 != NAT_HAIRPIN_NEXT_DROP;
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  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);
+    }
+
+  vlib_node_increment_counter (vm, stats_node_index,
+			       NAT44_HAIRPIN_ERROR_PROCESSED, pkts_processed);
+  return frame->n_vectors;
+}
+
+static uword
+snat_hairpin_dst_fn (vlib_main_t * vm,
+		     vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return snat_hairpin_dst_fn_inline (vm, node, frame, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (snat_hairpin_dst_node) = {
+  .function = snat_hairpin_dst_fn,
+  .name = "nat44-hairpin-dst",
+  .vector_size = sizeof (u32),
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .error_strings = nat44_hairpin_error_strings,
+  .n_next_nodes = NAT_HAIRPIN_N_NEXT,
+  .next_nodes = {
+    [NAT_HAIRPIN_NEXT_DROP] = "error-drop",
+    [NAT_HAIRPIN_NEXT_LOOKUP] = "ip4-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (snat_hairpin_dst_node, snat_hairpin_dst_fn);
+
+static uword
+nat44_ed_hairpin_dst_fn (vlib_main_t * vm,
+			 vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return snat_hairpin_dst_fn_inline (vm, node, frame, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_hairpin_dst_node) = {
+  .function = nat44_ed_hairpin_dst_fn,
+  .name = "nat44-ed-hairpin-dst",
+  .vector_size = sizeof (u32),
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .error_strings = nat44_hairpin_error_strings,
+  .n_next_nodes = NAT_HAIRPIN_N_NEXT,
+  .next_nodes = {
+    [NAT_HAIRPIN_NEXT_DROP] = "error-drop",
+    [NAT_HAIRPIN_NEXT_LOOKUP] = "ip4-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_hairpin_dst_node,
+			      nat44_ed_hairpin_dst_fn);
+
+static inline uword
+snat_hairpin_src_fn_inline (vlib_main_t * vm,
+			    vlib_node_runtime_t * node,
+			    vlib_frame_t * frame, int is_ed)
+{
+  u32 n_left_from, *from, *to_next, stats_node_index;
+  snat_hairpin_src_next_t next_index;
+  u32 pkts_processed = 0;
+  snat_main_t *sm = &snat_main;
+
+  stats_node_index = is_ed ? nat44_ed_hairpin_src_node.index :
+    snat_hairpin_src_node.index;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0;
+	  snat_interface_t *i;
+	  u32 sw_if_index0;
+
+	  /* speculatively enqueue b0 to the current next frame */
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+	  next0 = SNAT_HAIRPIN_SRC_NEXT_INTERFACE_OUTPUT;
+
+          /* *INDENT-OFF* */
+          pool_foreach (i, sm->output_feature_interfaces,
+          ({
+            /* Only packets from NAT inside interface */
+            if ((nat_interface_is_inside(i)) && (sw_if_index0 == i->sw_if_index))
+              {
+                if (PREDICT_FALSE ((vnet_buffer (b0)->snat.flags) &
+                                    SNAT_FLAG_HAIRPINNING))
+                  {
+                    if (PREDICT_TRUE (sm->num_workers > 1))
+                      next0 = SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT_WH;
+                    else
+                      next0 = SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT;
+                  }
+                break;
+              }
+          }));
+          /* *INDENT-ON* */
+
+	  pkts_processed += next0 != SNAT_HAIRPIN_SRC_NEXT_DROP;
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  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);
+    }
+
+  vlib_node_increment_counter (vm, stats_node_index,
+			       NAT44_HAIRPIN_ERROR_PROCESSED, pkts_processed);
+  return frame->n_vectors;
+}
+
+static uword
+snat_hairpin_src_fn (vlib_main_t * vm,
+		     vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return snat_hairpin_src_fn_inline (vm, node, frame, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (snat_hairpin_src_node) = {
+  .function = snat_hairpin_src_fn,
+  .name = "nat44-hairpin-src",
+  .vector_size = sizeof (u32),
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .error_strings = nat44_hairpin_error_strings,
+  .n_next_nodes = SNAT_HAIRPIN_SRC_N_NEXT,
+  .next_nodes = {
+     [SNAT_HAIRPIN_SRC_NEXT_DROP] = "error-drop",
+     [SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT] = "nat44-in2out-output",
+     [SNAT_HAIRPIN_SRC_NEXT_INTERFACE_OUTPUT] = "interface-output",
+     [SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT_WH] = "nat44-in2out-output-worker-handoff",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (snat_hairpin_src_node, snat_hairpin_src_fn);
+
+static uword
+nat44_ed_hairpin_src_fn (vlib_main_t * vm,
+			 vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return snat_hairpin_src_fn_inline (vm, node, frame, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_hairpin_src_node) = {
+  .function = nat44_ed_hairpin_src_fn,
+  .name = "nat44-ed-hairpin-src",
+  .vector_size = sizeof (u32),
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .error_strings = nat44_hairpin_error_strings,
+  .n_next_nodes = SNAT_HAIRPIN_SRC_N_NEXT,
+  .next_nodes = {
+     [SNAT_HAIRPIN_SRC_NEXT_DROP] = "error-drop",
+     [SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT] = "nat44-ed-in2out-output",
+     [SNAT_HAIRPIN_SRC_NEXT_INTERFACE_OUTPUT] = "interface-output",
+     [SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT_WH] = "nat44-in2out-output-worker-handoff",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_hairpin_src_node,
+			      nat44_ed_hairpin_src_fn);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */