NAT: Rename snat plugin to nat (VPP-955)

Change-Id: I30a7e3da7a4efc6038a91e27b48045d4b07e2764
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 1118 insertions, 0 deletions

diff --git a/src/plugins/nat/nat64_in2out.c b/src/plugins/nat/nat64_in2out.c
new file mode 100644
index 00000000..f78baff4
--- /dev/null
+++ b/src/plugins/nat/nat64_in2out.c
@@ -0,0 +1,1118 @@
+/*
+ * 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 NAT64 IPv6 to IPv4 translation (inside to outside network)
+ */
+
+#include <nat/nat64.h>
+#include <vnet/ip/ip6_to_ip4.h>
+#include <vnet/fib/fib_table.h>
+
+typedef struct
+{
+  u32 sw_if_index;
+  u32 next_index;
+  u8 is_slow_path;
+} nat64_in2out_trace_t;
+
+static u8 *
+format_nat64_in2out_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 *);
+  nat64_in2out_trace_t *t = va_arg (*args, nat64_in2out_trace_t *);
+  char *tag;
+
+  tag = t->is_slow_path ? "NAT64-in2out-slowpath" : "NAT64-in2out";
+
+  s =
+    format (s, "%s: sw_if_index %d, next index %d", tag, t->sw_if_index,
+	    t->next_index);
+
+  return s;
+}
+
+vlib_node_registration_t nat64_in2out_node;
+vlib_node_registration_t nat64_in2out_slowpath_node;
+
+#define foreach_nat64_in2out_error                 \
+_(UNSUPPORTED_PROTOCOL, "unsupported protocol")    \
+_(IN2OUT_PACKETS, "good in2out packets processed") \
+_(NO_TRANSLATION, "no translation")                \
+_(UNKNOWN, "unknown")
+
+typedef enum
+{
+#define _(sym,str) NAT64_IN2OUT_ERROR_##sym,
+  foreach_nat64_in2out_error
+#undef _
+    NAT64_IN2OUT_N_ERROR,
+} nat64_in2out_error_t;
+
+static char *nat64_in2out_error_strings[] = {
+#define _(sym,string) string,
+  foreach_nat64_in2out_error
+#undef _
+};
+
+typedef enum
+{
+  NAT64_IN2OUT_NEXT_IP4_LOOKUP,
+  NAT64_IN2OUT_NEXT_IP6_LOOKUP,
+  NAT64_IN2OUT_NEXT_DROP,
+  NAT64_IN2OUT_NEXT_SLOWPATH,
+  NAT64_IN2OUT_N_NEXT,
+} nat64_in2out_next_t;
+
+typedef struct nat64_in2out_set_ctx_t_
+{
+  vlib_buffer_t *b;
+  vlib_main_t *vm;
+} nat64_in2out_set_ctx_t;
+
+/**
+ * @brief Check whether is a hairpinning.
+ *
+ * If the destination IP address of the packet is an IPv4 address assigned to
+ * the NAT64 itself, then the packet is a hairpin packet.
+ *
+ * param dst_addr Destination address of the packet.
+ *
+ * @returns 1 if hairpinning, otherwise 0.
+ */
+static_always_inline int
+is_hairpinning (ip6_address_t * dst_addr)
+{
+  nat64_main_t *nm = &nat64_main;
+  int i;
+
+  for (i = 0; i < vec_len (nm->addr_pool); i++)
+    {
+      if (nm->addr_pool[i].addr.as_u32 == dst_addr->as_u32[3])
+	return 1;
+    }
+
+  return 0;
+}
+
+static int
+nat64_in2out_tcp_udp_set_cb (ip6_header_t * ip6, ip4_header_t * ip4,
+			     void *arg)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_in2out_set_ctx_t *ctx = arg;
+  nat64_db_bib_entry_t *bibe;
+  nat64_db_st_entry_t *ste;
+  ip46_address_t saddr, daddr;
+  u32 sw_if_index, fib_index;
+  udp_header_t *udp = ip6_next_header (ip6);
+  u8 proto = ip6->protocol;
+  u16 sport = udp->src_port;
+  u16 dport = udp->dst_port;
+
+  sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = ip6->dst_address.as_u64[1];
+
+  ste =
+    nat64_db_st_entry_find (&nm->db, &saddr, &daddr, sport, dport, proto,
+			    fib_index, 1);
+
+  if (ste)
+    {
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+    }
+  else
+    {
+      bibe =
+	nat64_db_bib_entry_find (&nm->db, &saddr, sport, proto, fib_index, 1);
+
+      if (!bibe)
+	{
+	  u16 out_port;
+	  ip4_address_t out_addr;
+	  if (nat64_alloc_out_addr_and_port
+	      (fib_index, ip_proto_to_snat_proto (proto), &out_addr,
+	       &out_port))
+	    return -1;
+
+	  bibe =
+	    nat64_db_bib_entry_create (&nm->db, &ip6->src_address, &out_addr,
+				       sport, clib_host_to_net_u16 (out_port),
+				       fib_index, proto, 0);
+	  if (!bibe)
+	    return -1;
+	}
+
+      nat64_extract_ip4 (&ip6->dst_address, &daddr.ip4, fib_index);
+      ste =
+	nat64_db_st_entry_create (&nm->db, bibe, &ip6->dst_address,
+				  &daddr.ip4, dport);
+      if (!ste)
+	return -1;
+    }
+
+  nat64_session_reset_timeout (ste, ctx->vm);
+
+  ip4->src_address.as_u32 = bibe->out_addr.as_u32;
+  udp->src_port = bibe->out_port;
+
+  ip4->dst_address.as_u32 = ste->out_r_addr.as_u32;
+
+  if (proto == IP_PROTOCOL_TCP)
+    {
+      u16 *checksum;
+      ip_csum_t csum;
+      tcp_header_t *tcp = ip6_next_header (ip6);
+
+      checksum = &tcp->checksum;
+      csum = ip_csum_sub_even (*checksum, sport);
+      csum = ip_csum_add_even (csum, udp->src_port);
+      *checksum = ip_csum_fold (csum);
+    }
+
+  return 0;
+}
+
+static int
+nat64_in2out_icmp_set_cb (ip6_header_t * ip6, ip4_header_t * ip4, void *arg)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_in2out_set_ctx_t *ctx = arg;
+  nat64_db_bib_entry_t *bibe;
+  nat64_db_st_entry_t *ste;
+  ip46_address_t saddr, daddr;
+  u32 sw_if_index, fib_index;
+  icmp46_header_t *icmp = ip6_next_header (ip6);
+
+  sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = ip6->dst_address.as_u64[1];
+
+  if (icmp->type == ICMP4_echo_request || icmp->type == ICMP4_echo_reply)
+    {
+      u16 in_id = ((u16 *) (icmp))[2];
+      ste =
+	nat64_db_st_entry_find (&nm->db, &saddr, &daddr, in_id, 0,
+				IP_PROTOCOL_ICMP, fib_index, 1);
+
+      if (ste)
+	{
+	  bibe =
+	    nat64_db_bib_entry_by_index (&nm->db, IP_PROTOCOL_ICMP,
+					 ste->bibe_index);
+	  if (!bibe)
+	    return -1;
+	}
+      else
+	{
+	  bibe =
+	    nat64_db_bib_entry_find (&nm->db, &saddr, in_id,
+				     IP_PROTOCOL_ICMP, fib_index, 1);
+
+	  if (!bibe)
+	    {
+	      u16 out_id;
+	      ip4_address_t out_addr;
+	      if (nat64_alloc_out_addr_and_port
+		  (fib_index, SNAT_PROTOCOL_ICMP, &out_addr, &out_id))
+		return -1;
+
+	      bibe =
+		nat64_db_bib_entry_create (&nm->db, &ip6->src_address,
+					   &out_addr, in_id,
+					   clib_host_to_net_u16 (out_id),
+					   fib_index, IP_PROTOCOL_ICMP, 0);
+	      if (!bibe)
+		return -1;
+	    }
+
+	  nat64_extract_ip4 (&ip6->dst_address, &daddr.ip4, fib_index);
+	  ste =
+	    nat64_db_st_entry_create (&nm->db, bibe, &ip6->dst_address,
+				      &daddr.ip4, 0);
+	  if (!ste)
+	    return -1;
+	}
+
+      nat64_session_reset_timeout (ste, ctx->vm);
+
+      ip4->src_address.as_u32 = bibe->out_addr.as_u32;
+      ((u16 *) (icmp))[2] = bibe->out_port;
+
+      ip4->dst_address.as_u32 = ste->out_r_addr.as_u32;
+    }
+  else
+    {
+      if (!vec_len (nm->addr_pool))
+	return -1;
+
+      ip4->src_address.as_u32 = nm->addr_pool[0].addr.as_u32;
+      nat64_extract_ip4 (&ip6->dst_address, &ip4->dst_address, fib_index);
+    }
+
+  return 0;
+}
+
+static int
+nat64_in2out_inner_icmp_set_cb (ip6_header_t * ip6, ip4_header_t * ip4,
+				void *arg)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_in2out_set_ctx_t *ctx = arg;
+  nat64_db_st_entry_t *ste;
+  nat64_db_bib_entry_t *bibe;
+  ip46_address_t saddr, daddr;
+  u32 sw_if_index, fib_index;
+  u8 proto = ip6->protocol;
+
+  sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = ip6->dst_address.as_u64[1];
+
+  if (proto == IP_PROTOCOL_ICMP6)
+    {
+      icmp46_header_t *icmp = ip6_next_header (ip6);
+      u16 in_id = ((u16 *) (icmp))[2];
+      proto = IP_PROTOCOL_ICMP;
+
+      if (!
+	  (icmp->type == ICMP4_echo_request
+	   || icmp->type == ICMP4_echo_reply))
+	return -1;
+
+      ste =
+	nat64_db_st_entry_find (&nm->db, &daddr, &saddr, in_id, 0, proto,
+				fib_index, 1);
+      if (!ste)
+	return -1;
+
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+
+      ip4->dst_address.as_u32 = bibe->out_addr.as_u32;
+      ((u16 *) (icmp))[2] = bibe->out_port;
+      ip4->src_address.as_u32 = ste->out_r_addr.as_u32;
+    }
+  else
+    {
+      udp_header_t *udp = ip6_next_header (ip6);
+      tcp_header_t *tcp = ip6_next_header (ip6);
+      u16 *checksum;
+      ip_csum_t csum;
+
+      u16 sport = udp->src_port;
+      u16 dport = udp->dst_port;
+
+      ste =
+	nat64_db_st_entry_find (&nm->db, &daddr, &saddr, dport, sport, proto,
+				fib_index, 1);
+      if (!ste)
+	return -1;
+
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+
+      ip4->dst_address.as_u32 = bibe->out_addr.as_u32;
+      udp->dst_port = bibe->out_port;
+      ip4->src_address.as_u32 = ste->out_r_addr.as_u32;
+
+      if (proto == IP_PROTOCOL_TCP)
+	checksum = &tcp->checksum;
+      else
+	checksum = &udp->checksum;
+      csum = ip_csum_sub_even (*checksum, dport);
+      csum = ip_csum_add_even (csum, udp->dst_port);
+      *checksum = ip_csum_fold (csum);
+    }
+
+  return 0;
+}
+
+typedef struct unk_proto_st_walk_ctx_t_
+{
+  ip6_address_t src_addr;
+  ip6_address_t dst_addr;
+  ip4_address_t out_addr;
+  u32 fib_index;
+  u8 proto;
+} unk_proto_st_walk_ctx_t;
+
+static int
+unk_proto_st_walk (nat64_db_st_entry_t * ste, void *arg)
+{
+  nat64_main_t *nm = &nat64_main;
+  unk_proto_st_walk_ctx_t *ctx = arg;
+  nat64_db_bib_entry_t *bibe;
+  ip46_address_t saddr, daddr;
+
+  if (ip46_address_is_equal (&ste->in_r_addr, &ctx->dst_addr))
+    {
+      bibe =
+	nat64_db_bib_entry_by_index (&nm->db, ste->proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+
+      if (ip46_address_is_equal (&bibe->in_addr, &ctx->src_addr)
+	  && bibe->fib_index == ctx->fib_index)
+	{
+	  memset (&saddr, 0, sizeof (saddr));
+	  saddr.ip4.as_u32 = bibe->out_addr.as_u32;
+	  memset (&daddr, 0, sizeof (daddr));
+	  nat64_extract_ip4 (&ctx->dst_addr, &daddr.ip4, ctx->fib_index);
+
+	  if (nat64_db_st_entry_find
+	      (&nm->db, &daddr, &saddr, 0, 0, ctx->proto, ctx->fib_index, 0))
+	    return -1;
+
+	  ctx->out_addr.as_u32 = bibe->out_addr.as_u32;
+	  return 1;
+	}
+    }
+
+  return 0;
+}
+
+static int
+nat64_in2out_unk_proto_set_cb (ip6_header_t * ip6, ip4_header_t * ip4,
+			       void *arg)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_in2out_set_ctx_t *ctx = arg;
+  nat64_db_bib_entry_t *bibe;
+  nat64_db_st_entry_t *ste;
+  ip46_address_t saddr, daddr, addr;
+  u32 sw_if_index, fib_index;
+  u8 proto = ip6->protocol;
+  int i;
+
+  sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = ip6->dst_address.as_u64[1];
+
+  ste =
+    nat64_db_st_entry_find (&nm->db, &saddr, &daddr, 0, 0, proto, fib_index,
+			    1);
+
+  if (ste)
+    {
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+    }
+  else
+    {
+      bibe =
+	nat64_db_bib_entry_find (&nm->db, &saddr, 0, proto, fib_index, 1);
+
+      if (!bibe)
+	{
+	  /* Choose same out address as for TCP/UDP session to same dst */
+	  unk_proto_st_walk_ctx_t ctx = {
+	    .src_addr.as_u64[0] = ip6->src_address.as_u64[0],
+	    .src_addr.as_u64[1] = ip6->src_address.as_u64[1],
+	    .dst_addr.as_u64[0] = ip6->dst_address.as_u64[0],
+	    .dst_addr.as_u64[1] = ip6->dst_address.as_u64[1],
+	    .out_addr.as_u32 = 0,
+	    .fib_index = fib_index,
+	    .proto = proto,
+	  };
+
+	  nat64_db_st_walk (&nm->db, IP_PROTOCOL_TCP, unk_proto_st_walk,
+			    &ctx);
+
+	  if (!ctx.out_addr.as_u32)
+	    nat64_db_st_walk (&nm->db, IP_PROTOCOL_UDP, unk_proto_st_walk,
+			      &ctx);
+
+	  /* Verify if out address is not already in use for protocol */
+	  memset (&addr, 0, sizeof (addr));
+	  addr.ip4.as_u32 = ctx.out_addr.as_u32;
+	  if (nat64_db_bib_entry_find (&nm->db, &addr, 0, proto, 0, 0))
+	    ctx.out_addr.as_u32 = 0;
+
+	  if (!ctx.out_addr.as_u32)
+	    {
+	      for (i = 0; i < vec_len (nm->addr_pool); i++)
+		{
+		  addr.ip4.as_u32 = nm->addr_pool[i].addr.as_u32;
+		  if (!nat64_db_bib_entry_find
+		      (&nm->db, &addr, 0, proto, 0, 0))
+		    break;
+		}
+	    }
+
+	  if (!ctx.out_addr.as_u32)
+	    return -1;
+
+	  bibe =
+	    nat64_db_bib_entry_create (&nm->db, &ip6->src_address,
+				       &ctx.out_addr, 0, 0, fib_index, proto,
+				       0);
+	  if (!bibe)
+	    return -1;
+	}
+
+      nat64_extract_ip4 (&ip6->dst_address, &daddr.ip4, fib_index);
+      ste =
+	nat64_db_st_entry_create (&nm->db, bibe, &ip6->dst_address,
+				  &daddr.ip4, 0);
+      if (!ste)
+	return -1;
+    }
+
+  nat64_session_reset_timeout (ste, ctx->vm);
+
+  ip4->src_address.as_u32 = bibe->out_addr.as_u32;
+  ip4->dst_address.as_u32 = ste->out_r_addr.as_u32;
+
+  return 0;
+}
+
+
+
+static int
+nat64_in2out_tcp_udp_hairpinning (vlib_main_t * vm, vlib_buffer_t * b,
+				  ip6_header_t * ip6)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_db_bib_entry_t *bibe;
+  nat64_db_st_entry_t *ste;
+  ip46_address_t saddr, daddr;
+  u32 sw_if_index, fib_index;
+  udp_header_t *udp = ip6_next_header (ip6);
+  tcp_header_t *tcp = ip6_next_header (ip6);
+  u8 proto = ip6->protocol;
+  u16 sport = udp->src_port;
+  u16 dport = udp->dst_port;
+  u16 *checksum;
+  ip_csum_t csum;
+
+  sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = ip6->dst_address.as_u64[1];
+
+  if (proto == IP_PROTOCOL_UDP)
+    checksum = &udp->checksum;
+  else
+    checksum = &tcp->checksum;
+
+  csum = ip_csum_sub_even (*checksum, ip6->src_address.as_u64[0]);
+  csum = ip_csum_sub_even (csum, ip6->src_address.as_u64[1]);
+  csum = ip_csum_sub_even (csum, ip6->dst_address.as_u64[0]);
+  csum = ip_csum_sub_even (csum, ip6->dst_address.as_u64[1]);
+  csum = ip_csum_sub_even (csum, sport);
+  csum = ip_csum_sub_even (csum, dport);
+
+  ste =
+    nat64_db_st_entry_find (&nm->db, &saddr, &daddr, sport, dport, proto,
+			    fib_index, 1);
+
+  if (ste)
+    {
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+    }
+  else
+    {
+      bibe =
+	nat64_db_bib_entry_find (&nm->db, &saddr, sport, proto, fib_index, 1);
+
+      if (!bibe)
+	{
+	  u16 out_port;
+	  ip4_address_t out_addr;
+	  if (nat64_alloc_out_addr_and_port
+	      (fib_index, ip_proto_to_snat_proto (proto), &out_addr,
+	       &out_port))
+	    return -1;
+
+	  bibe =
+	    nat64_db_bib_entry_create (&nm->db, &ip6->src_address, &out_addr,
+				       sport, clib_host_to_net_u16 (out_port),
+				       fib_index, proto, 0);
+	  if (!bibe)
+	    return -1;
+	}
+
+      nat64_extract_ip4 (&ip6->dst_address, &daddr.ip4, fib_index);
+      ste =
+	nat64_db_st_entry_create (&nm->db, bibe, &ip6->dst_address,
+				  &daddr.ip4, dport);
+      if (!ste)
+	return -1;
+    }
+
+  nat64_session_reset_timeout (ste, vm);
+
+  sport = udp->src_port = bibe->out_port;
+  nat64_compose_ip6 (&ip6->src_address, &bibe->out_addr, fib_index);
+
+  memset (&saddr, 0, sizeof (saddr));
+  memset (&daddr, 0, sizeof (daddr));
+  saddr.ip4.as_u32 = bibe->out_addr.as_u32;
+  daddr.ip4.as_u32 = ste->out_r_addr.as_u32;
+
+  ste =
+    nat64_db_st_entry_find (&nm->db, &daddr, &saddr, dport, sport, proto, 0,
+			    0);
+
+  if (ste)
+    {
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+    }
+  else
+    {
+      bibe = nat64_db_bib_entry_find (&nm->db, &daddr, dport, proto, 0, 0);
+
+      if (!bibe)
+	return -1;
+
+      ste =
+	nat64_db_st_entry_create (&nm->db, bibe, &ip6->src_address,
+				  &saddr.ip4, sport);
+    }
+
+  ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
+  ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
+  udp->dst_port = bibe->in_port;
+
+  csum = ip_csum_add_even (csum, ip6->src_address.as_u64[0]);
+  csum = ip_csum_add_even (csum, ip6->src_address.as_u64[1]);
+  csum = ip_csum_add_even (csum, ip6->dst_address.as_u64[0]);
+  csum = ip_csum_add_even (csum, ip6->dst_address.as_u64[1]);
+  csum = ip_csum_add_even (csum, udp->src_port);
+  csum = ip_csum_add_even (csum, udp->dst_port);
+  *checksum = ip_csum_fold (csum);
+
+  return 0;
+}
+
+static int
+nat64_in2out_icmp_hairpinning (vlib_main_t * vm, vlib_buffer_t * b,
+			       ip6_header_t * ip6)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_db_bib_entry_t *bibe;
+  nat64_db_st_entry_t *ste;
+  icmp46_header_t *icmp = ip6_next_header (ip6);
+  ip6_header_t *inner_ip6;
+  ip46_address_t saddr, daddr;
+  u32 sw_if_index, fib_index;
+  u8 proto;
+  udp_header_t *udp;
+  tcp_header_t *tcp;
+  u16 *checksum, sport, dport;
+  ip_csum_t csum;
+
+  if (icmp->type == ICMP6_echo_request || icmp->type == ICMP6_echo_reply)
+    return -1;
+
+  inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8);
+
+  proto = inner_ip6->protocol;
+
+  if (proto == IP_PROTOCOL_ICMP6)
+    return -1;
+
+  sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = inner_ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = inner_ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = inner_ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = inner_ip6->dst_address.as_u64[1];
+
+  udp = ip6_next_header (inner_ip6);
+  tcp = ip6_next_header (inner_ip6);
+
+  sport = udp->src_port;
+  dport = udp->dst_port;
+
+  if (proto == IP_PROTOCOL_UDP)
+    checksum = &udp->checksum;
+  else
+    checksum = &tcp->checksum;
+
+  csum = ip_csum_sub_even (*checksum, inner_ip6->src_address.as_u64[0]);
+  csum = ip_csum_sub_even (csum, inner_ip6->src_address.as_u64[1]);
+  csum = ip_csum_sub_even (csum, inner_ip6->dst_address.as_u64[0]);
+  csum = ip_csum_sub_even (csum, inner_ip6->dst_address.as_u64[1]);
+  csum = ip_csum_sub_even (csum, sport);
+  csum = ip_csum_sub_even (csum, dport);
+
+  ste =
+    nat64_db_st_entry_find (&nm->db, &daddr, &saddr, dport, sport, proto,
+			    fib_index, 1);
+  if (!ste)
+    return -1;
+
+  bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+  if (!bibe)
+    return -1;
+
+  dport = udp->dst_port = bibe->out_port;
+  nat64_compose_ip6 (&inner_ip6->dst_address, &bibe->out_addr, fib_index);
+
+  memset (&saddr, 0, sizeof (saddr));
+  memset (&daddr, 0, sizeof (daddr));
+  saddr.ip4.as_u32 = ste->out_r_addr.as_u32;
+  daddr.ip4.as_u32 = bibe->out_addr.as_u32;
+
+  ste =
+    nat64_db_st_entry_find (&nm->db, &saddr, &daddr, sport, dport, proto, 0,
+			    0);
+  if (!ste)
+    return -1;
+
+  bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+  if (!bibe)
+    return -1;
+
+  inner_ip6->src_address.as_u64[0] = bibe->in_addr.as_u64[0];
+  inner_ip6->src_address.as_u64[1] = bibe->in_addr.as_u64[1];
+  udp->src_port = bibe->in_port;
+
+  csum = ip_csum_add_even (csum, inner_ip6->src_address.as_u64[0]);
+  csum = ip_csum_add_even (csum, inner_ip6->src_address.as_u64[1]);
+  csum = ip_csum_add_even (csum, inner_ip6->dst_address.as_u64[0]);
+  csum = ip_csum_add_even (csum, inner_ip6->dst_address.as_u64[1]);
+  csum = ip_csum_add_even (csum, udp->src_port);
+  csum = ip_csum_add_even (csum, udp->dst_port);
+  *checksum = ip_csum_fold (csum);
+
+  if (!vec_len (nm->addr_pool))
+    return -1;
+
+  nat64_compose_ip6 (&ip6->src_address, &nm->addr_pool[0].addr, fib_index);
+  ip6->dst_address.as_u64[0] = inner_ip6->src_address.as_u64[0];
+  ip6->dst_address.as_u64[1] = inner_ip6->src_address.as_u64[1];
+
+  icmp->checksum = 0;
+  csum = ip_csum_with_carry (0, ip6->payload_length);
+  csum = ip_csum_with_carry (csum, clib_host_to_net_u16 (ip6->protocol));
+  csum = ip_csum_with_carry (csum, ip6->src_address.as_u64[0]);
+  csum = ip_csum_with_carry (csum, ip6->src_address.as_u64[1]);
+  csum = ip_csum_with_carry (csum, ip6->dst_address.as_u64[0]);
+  csum = ip_csum_with_carry (csum, ip6->dst_address.as_u64[1]);
+  csum =
+    ip_incremental_checksum (csum, icmp,
+			     clib_net_to_host_u16 (ip6->payload_length));
+  icmp->checksum = ~ip_csum_fold (csum);
+
+  return 0;
+}
+
+static int
+nat64_in2out_unk_proto_hairpinning (vlib_main_t * vm, vlib_buffer_t * b,
+				    ip6_header_t * ip6)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_db_bib_entry_t *bibe;
+  nat64_db_st_entry_t *ste;
+  ip46_address_t saddr, daddr, addr;
+  u32 sw_if_index, fib_index;
+  u8 proto = ip6->protocol;
+  int i;
+
+  sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = ip6->dst_address.as_u64[1];
+
+  ste =
+    nat64_db_st_entry_find (&nm->db, &saddr, &daddr, 0, 0, proto, fib_index,
+			    1);
+
+  if (ste)
+    {
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+    }
+  else
+    {
+      bibe =
+	nat64_db_bib_entry_find (&nm->db, &saddr, 0, proto, fib_index, 1);
+
+      if (!bibe)
+	{
+	  /* Choose same out address as for TCP/UDP session to same dst */
+	  unk_proto_st_walk_ctx_t ctx = {
+	    .src_addr.as_u64[0] = ip6->src_address.as_u64[0],
+	    .src_addr.as_u64[1] = ip6->src_address.as_u64[1],
+	    .dst_addr.as_u64[0] = ip6->dst_address.as_u64[0],
+	    .dst_addr.as_u64[1] = ip6->dst_address.as_u64[1],
+	    .out_addr.as_u32 = 0,
+	    .fib_index = fib_index,
+	    .proto = proto,
+	  };
+
+	  nat64_db_st_walk (&nm->db, IP_PROTOCOL_TCP, unk_proto_st_walk,
+			    &ctx);
+
+	  if (!ctx.out_addr.as_u32)
+	    nat64_db_st_walk (&nm->db, IP_PROTOCOL_UDP, unk_proto_st_walk,
+			      &ctx);
+
+	  /* Verify if out address is not already in use for protocol */
+	  memset (&addr, 0, sizeof (addr));
+	  addr.ip4.as_u32 = ctx.out_addr.as_u32;
+	  if (nat64_db_bib_entry_find (&nm->db, &addr, 0, proto, 0, 0))
+	    ctx.out_addr.as_u32 = 0;
+
+	  if (!ctx.out_addr.as_u32)
+	    {
+	      for (i = 0; i < vec_len (nm->addr_pool); i++)
+		{
+		  addr.ip4.as_u32 = nm->addr_pool[i].addr.as_u32;
+		  if (!nat64_db_bib_entry_find
+		      (&nm->db, &addr, 0, proto, 0, 0))
+		    break;
+		}
+	    }
+
+	  if (!ctx.out_addr.as_u32)
+	    return -1;
+
+	  bibe =
+	    nat64_db_bib_entry_create (&nm->db, &ip6->src_address,
+				       &ctx.out_addr, 0, 0, fib_index, proto,
+				       0);
+	  if (!bibe)
+	    return -1;
+	}
+
+      nat64_extract_ip4 (&ip6->dst_address, &daddr.ip4, fib_index);
+      ste =
+	nat64_db_st_entry_create (&nm->db, bibe, &ip6->dst_address,
+				  &daddr.ip4, 0);
+      if (!ste)
+	return -1;
+    }
+
+  nat64_session_reset_timeout (ste, vm);
+
+  nat64_compose_ip6 (&ip6->src_address, &bibe->out_addr, fib_index);
+
+  memset (&saddr, 0, sizeof (saddr));
+  memset (&daddr, 0, sizeof (daddr));
+  saddr.ip4.as_u32 = bibe->out_addr.as_u32;
+  daddr.ip4.as_u32 = ste->out_r_addr.as_u32;
+
+  ste = nat64_db_st_entry_find (&nm->db, &daddr, &saddr, 0, 0, proto, 0, 0);
+
+  if (ste)
+    {
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+    }
+  else
+    {
+      bibe = nat64_db_bib_entry_find (&nm->db, &daddr, 0, proto, 0, 0);
+
+      if (!bibe)
+	return -1;
+
+      ste =
+	nat64_db_st_entry_create (&nm->db, bibe, &ip6->src_address,
+				  &saddr.ip4, 0);
+    }
+
+  ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
+  ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
+
+  return 0;
+}
+
+static inline uword
+nat64_in2out_node_fn_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
+			     vlib_frame_t * frame, u8 is_slow_path)
+{
+  u32 n_left_from, *from, *to_next;
+  nat64_in2out_next_t next_index;
+  u32 pkts_processed = 0;
+  u32 stats_node_index;
+
+  stats_node_index =
+    is_slow_path ? nat64_in2out_slowpath_node.index : nat64_in2out_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;
+	  ip6_header_t *ip60;
+	  u16 l4_offset0, frag_offset0;
+	  u8 l4_protocol0;
+	  u32 proto0;
+	  nat64_in2out_set_ctx_t ctx0;
+
+	  /* 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);
+	  ip60 = vlib_buffer_get_current (b0);
+
+	  ctx0.b = b0;
+	  ctx0.vm = vm;
+
+	  next0 = NAT64_IN2OUT_NEXT_IP4_LOOKUP;
+
+	  if (PREDICT_FALSE
+	      (ip6_parse
+	       (ip60, b0->current_length, &l4_protocol0, &l4_offset0,
+		&frag_offset0)))
+	    {
+	      next0 = NAT64_IN2OUT_NEXT_DROP;
+	      b0->error = node->errors[NAT64_IN2OUT_ERROR_UNKNOWN];
+	      goto trace0;
+	    }
+
+	  proto0 = ip_proto_to_snat_proto (l4_protocol0);
+	  if (frag_offset0 != 0)
+	    {
+	      next0 = NAT64_IN2OUT_NEXT_DROP;
+	      b0->error =
+		node->errors[NAT64_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
+	      goto trace0;
+	    }
+
+	  if (is_slow_path)
+	    {
+	      if (PREDICT_TRUE (proto0 == ~0))
+		{
+		  if (is_hairpinning (&ip60->dst_address))
+		    {
+		      next0 = NAT64_IN2OUT_NEXT_IP6_LOOKUP;
+		      if (nat64_in2out_unk_proto_hairpinning (vm, b0, ip60))
+			{
+			  next0 = NAT64_IN2OUT_NEXT_DROP;
+			  b0->error =
+			    node->errors[NAT64_IN2OUT_ERROR_NO_TRANSLATION];
+			}
+		      goto trace0;
+		    }
+
+		  if (ip6_to_ip4 (b0, nat64_in2out_unk_proto_set_cb, &ctx0))
+		    {
+		      next0 = NAT64_IN2OUT_NEXT_DROP;
+		      b0->error =
+			node->errors[NAT64_IN2OUT_ERROR_NO_TRANSLATION];
+		      goto trace0;
+		    }
+		}
+	      goto trace0;
+	    }
+	  else
+	    {
+	      if (PREDICT_FALSE (proto0 == ~0))
+		{
+		  next0 = NAT64_IN2OUT_NEXT_SLOWPATH;
+		  goto trace0;
+		}
+	    }
+
+	  if (proto0 == SNAT_PROTOCOL_ICMP)
+	    {
+	      if (is_hairpinning (&ip60->dst_address))
+		{
+		  next0 = NAT64_IN2OUT_NEXT_IP6_LOOKUP;
+		  if (nat64_in2out_icmp_hairpinning (vm, b0, ip60))
+		    {
+		      next0 = NAT64_IN2OUT_NEXT_DROP;
+		      b0->error =
+			node->errors[NAT64_IN2OUT_ERROR_NO_TRANSLATION];
+		    }
+		  goto trace0;
+		}
+
+	      if (icmp6_to_icmp
+		  (b0, nat64_in2out_icmp_set_cb, &ctx0,
+		   nat64_in2out_inner_icmp_set_cb, &ctx0))
+		{
+		  next0 = NAT64_IN2OUT_NEXT_DROP;
+		  b0->error = node->errors[NAT64_IN2OUT_ERROR_NO_TRANSLATION];
+		  goto trace0;
+		}
+	    }
+	  else if (proto0 == SNAT_PROTOCOL_TCP || proto0 == SNAT_PROTOCOL_UDP)
+	    {
+	      if (is_hairpinning (&ip60->dst_address))
+		{
+		  next0 = NAT64_IN2OUT_NEXT_IP6_LOOKUP;
+		  if (nat64_in2out_tcp_udp_hairpinning (vm, b0, ip60))
+		    {
+		      next0 = NAT64_IN2OUT_NEXT_DROP;
+		      b0->error =
+			node->errors[NAT64_IN2OUT_ERROR_NO_TRANSLATION];
+		    }
+		  goto trace0;
+		}
+
+	      if (ip6_to_ip4_tcp_udp
+		  (b0, nat64_in2out_tcp_udp_set_cb, &ctx0, 0))
+		{
+		  next0 = NAT64_IN2OUT_NEXT_DROP;
+		  b0->error = node->errors[NAT64_IN2OUT_ERROR_NO_TRANSLATION];
+		  goto trace0;
+		}
+	    }
+
+	trace0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat64_in2out_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+	      t->next_index = next0;
+	      t->is_slow_path = is_slow_path;
+	    }
+
+	  pkts_processed += next0 != NAT64_IN2OUT_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,
+			       NAT64_IN2OUT_ERROR_IN2OUT_PACKETS,
+			       pkts_processed);
+  return frame->n_vectors;
+}
+
+static uword
+nat64_in2out_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+		      vlib_frame_t * frame)
+{
+  return nat64_in2out_node_fn_inline (vm, node, frame, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat64_in2out_node) = {
+  .function = nat64_in2out_node_fn,
+  .name = "nat64-in2out",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat64_in2out_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat64_in2out_error_strings),
+  .error_strings = nat64_in2out_error_strings,
+  .n_next_nodes = NAT64_IN2OUT_N_NEXT,
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [NAT64_IN2OUT_NEXT_DROP] = "error-drop",
+    [NAT64_IN2OUT_NEXT_IP4_LOOKUP] = "ip4-lookup",
+    [NAT64_IN2OUT_NEXT_IP6_LOOKUP] = "ip6-lookup",
+    [NAT64_IN2OUT_NEXT_SLOWPATH] = "nat64-in2out-slowpath",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat64_in2out_node, nat64_in2out_node_fn);
+
+static uword
+nat64_in2out_slowpath_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+			       vlib_frame_t * frame)
+{
+  return nat64_in2out_node_fn_inline (vm, node, frame, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat64_in2out_slowpath_node) = {
+  .function = nat64_in2out_slowpath_node_fn,
+  .name = "nat64-in2out-slowpath",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat64_in2out_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat64_in2out_error_strings),
+  .error_strings = nat64_in2out_error_strings,
+  .n_next_nodes = NAT64_IN2OUT_N_NEXT,
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [NAT64_IN2OUT_NEXT_DROP] = "error-drop",
+    [NAT64_IN2OUT_NEXT_IP4_LOOKUP] = "ip4-lookup",
+    [NAT64_IN2OUT_NEXT_IP6_LOOKUP] = "ip6-lookup",
+    [NAT64_IN2OUT_NEXT_SLOWPATH] = "nat64-in2out-slowpath",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat64_in2out_slowpath_node,
+			      nat64_in2out_slowpath_node_fn);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */