nat: use SVR

Remove NAT's implementation of shallow virtual reassembly with
corresponding CLIs, APIs & tests. Replace with standalone shallow
virtual reassembly provided by ipX-sv-reass* nodes.

Type: refactor
Change-Id: I7e6c7487a5a500d591f6871474a359e0993e59b6
Signed-off-by: Klement Sekera <ksekera@cisco.com>

1 files changed, 157 insertions, 412 deletions

diff --git a/src/plugins/nat/nat64_out2in.c b/src/plugins/nat/nat64_out2in.c
index e0dd407e0cf..6c0075102a1 100644
--- a/src/plugins/nat/nat64_out2in.c
+++ b/src/plugins/nat/nat64_out2in.c
@@ -18,7 +18,6 @@
  */
 
 #include <nat/nat64.h>
-#include <nat/nat_reass.h>
 #include <nat/nat_inlines.h>
 #include <vnet/ip/ip4_to_ip6.h>
 #include <vnet/fib/ip4_fib.h>
@@ -44,38 +43,12 @@ format_nat64_out2in_trace (u8 * s, va_list * args)
   return s;
 }
 
-typedef struct
-{
-  u32 sw_if_index;
-  u32 next_index;
-  u8 cached;
-} nat64_out2in_reass_trace_t;
-
-static u8 *
-format_nat64_out2in_reass_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_out2in_reass_trace_t *t =
-    va_arg (*args, nat64_out2in_reass_trace_t *);
-
-  s =
-    format (s, "NAT64-out2in-reass: sw_if_index %d, next index %d, status %s",
-	    t->sw_if_index, t->next_index,
-	    t->cached ? "cached" : "translated");
-
-  return s;
-}
-
-
 #define foreach_nat64_out2in_error                       \
 _(UNSUPPORTED_PROTOCOL, "unsupported protocol")          \
 _(OUT2IN_PACKETS, "good out2in packets processed")       \
 _(NO_TRANSLATION, "no translation")                      \
 _(UNKNOWN, "unknown")                                    \
 _(DROP_FRAGMENT, "drop fragment")                        \
-_(MAX_REASS, "maximum reassemblies exceeded")            \
-_(MAX_FRAG, "maximum fragments per reassembly exceeded") \
 _(TCP_PACKETS, "TCP packets")                            \
 _(UDP_PACKETS, "UDP packets")                            \
 _(ICMP_PACKETS, "ICMP packets")                          \
@@ -104,7 +77,6 @@ typedef enum
   NAT64_OUT2IN_NEXT_IP6_LOOKUP,
   NAT64_OUT2IN_NEXT_IP4_LOOKUP,
   NAT64_OUT2IN_NEXT_DROP,
-  NAT64_OUT2IN_NEXT_REASS,
   NAT64_OUT2IN_N_NEXT,
 } nat64_out2in_next_t;
 
@@ -116,25 +88,90 @@ typedef struct nat64_out2in_set_ctx_t_
 } nat64_out2in_set_ctx_t;
 
 static int
-nat64_out2in_tcp_udp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
-			     void *arg)
+nat64_out2in_tcp_udp (vlib_main_t * vm, vlib_buffer_t * b,
+		      nat64_out2in_set_ctx_t * ctx)
 {
+  ip4_header_t *ip4;
+  ip6_header_t *ip6;
+  ip_csum_t csum;
+  u16 *checksum = NULL;
+  ip6_frag_hdr_t *frag;
+  u32 frag_id;
+  ip4_address_t old_src, old_dst;
+
   nat64_main_t *nm = &nat64_main;
-  nat64_out2in_set_ctx_t *ctx = arg;
   nat64_db_bib_entry_t *bibe;
   nat64_db_st_entry_t *ste;
-  ip46_address_t saddr, daddr;
+  ip46_address_t saddr;
+  ip46_address_t daddr;
   ip6_address_t ip6_saddr;
-  udp_header_t *udp = ip4_next_header (ip4);
-  tcp_header_t *tcp = ip4_next_header (ip4);
-  u8 proto = ip4->protocol;
-  u16 dport = udp->dst_port;
-  u16 sport = udp->src_port;
+  u8 proto = vnet_buffer (b)->ip.reass.ip_proto;
+  u16 dport = vnet_buffer (b)->ip.reass.l4_dst_port;
+  u16 sport = vnet_buffer (b)->ip.reass.l4_src_port;
   u32 sw_if_index, fib_index;
-  u16 *checksum;
-  ip_csum_t csum;
   nat64_db_t *db = &nm->db[ctx->thread_index];
 
+  ip4 = vlib_buffer_get_current (b);
+
+  udp_header_t *udp = ip4_next_header (ip4);
+  tcp_header_t *tcp = ip4_next_header (ip4);
+  if (!vnet_buffer (b)->ip.reass.is_non_first_fragment)
+    {
+      if (ip4->protocol == IP_PROTOCOL_UDP)
+	{
+	  checksum = &udp->checksum;
+	  //UDP checksum is optional over IPv4 but mandatory for IPv6
+	  //We do not check udp->length sanity but use our safe computed value instead
+	  if (PREDICT_FALSE (!*checksum))
+	    {
+	      u16 udp_len =
+		clib_host_to_net_u16 (ip4->length) - sizeof (*ip4);
+	      csum = ip_incremental_checksum (0, udp, udp_len);
+	      csum =
+		ip_csum_with_carry (csum, clib_host_to_net_u16 (udp_len));
+	      csum =
+		ip_csum_with_carry (csum,
+				    clib_host_to_net_u16 (IP_PROTOCOL_UDP));
+	      csum =
+		ip_csum_with_carry (csum, *((u64 *) (&ip4->src_address)));
+	      *checksum = ~ip_csum_fold (csum);
+	    }
+	}
+      else
+	{
+	  checksum = &tcp->checksum;
+	}
+    }
+
+  old_src.as_u32 = ip4->src_address.as_u32;
+  old_dst.as_u32 = ip4->dst_address.as_u32;
+
+  // Deal with fragmented packets
+  u16 frag_offset = ip4_get_fragment_offset (ip4);
+  if (PREDICT_FALSE (ip4_get_fragment_more (ip4) || frag_offset))
+    {
+      ip6 =
+	(ip6_header_t *) u8_ptr_add (ip4,
+				     sizeof (*ip4) - sizeof (*ip6) -
+				     sizeof (*frag));
+      frag =
+	(ip6_frag_hdr_t *) u8_ptr_add (ip4, sizeof (*ip4) - sizeof (*frag));
+      frag_id = frag_id_4to6 (ip4->fragment_id);
+      vlib_buffer_advance (b, sizeof (*ip4) - sizeof (*ip6) - sizeof (*frag));
+    }
+  else
+    {
+      ip6 = (ip6_header_t *) (((u8 *) ip4) + sizeof (*ip4) - sizeof (*ip6));
+      vlib_buffer_advance (b, sizeof (*ip4) - sizeof (*ip6));
+      frag = NULL;
+    }
+
+  ip6->ip_version_traffic_class_and_flow_label =
+    clib_host_to_net_u32 ((6 << 28) + (ip4->tos << 20));
+  ip6->payload_length = u16_net_add (ip4->length, -sizeof (*ip4));
+  ip6->hop_limit = ip4->ttl;
+  ip6->protocol = ip4->protocol;
+
   sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
   fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 
@@ -159,7 +196,7 @@ nat64_out2in_tcp_udp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
       if (!bibe)
 	return -1;
 
-      nat64_compose_ip6 (&ip6_saddr, &ip4->src_address, bibe->fib_index);
+      nat64_compose_ip6 (&ip6_saddr, &old_src, bibe->fib_index);
       ste =
 	nat64_db_st_entry_create (ctx->thread_index, db, bibe, &ip6_saddr,
 				  &saddr.ip4, sport);
@@ -176,29 +213,48 @@ nat64_out2in_tcp_udp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
 
   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;
 
-  if (proto == IP_PROTOCOL_UDP)
-    checksum = &udp->checksum;
-  else
+  vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
+
+  nat64_session_reset_timeout (ste, ctx->vm);
+
+  if (PREDICT_FALSE (frag != NULL))
     {
-      checksum = &tcp->checksum;
-      nat64_tcp_session_set_state (ste, tcp, 0);
+      frag->next_hdr = ip6->protocol;
+      frag->identification = frag_id;
+      frag->rsv = 0;
+      frag->fragment_offset_and_more =
+	ip6_frag_hdr_offset_and_more (frag_offset, 1);
+      ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
+      ip6->payload_length = u16_net_add (ip6->payload_length, sizeof (*frag));
     }
 
-  csum = ip_csum_sub_even (*checksum, dport);
-  csum = ip_csum_add_even (csum, udp->dst_port);
-  *checksum = ip_csum_fold (csum);
+  if (!vnet_buffer (b)->ip.reass.is_non_first_fragment)
+    {
+      udp->dst_port = bibe->in_port;
 
-  vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
+      if (proto == IP_PROTOCOL_TCP)
+	{
+	  nat64_tcp_session_set_state (ste, tcp, 0);
+	}
 
-  nat64_session_reset_timeout (ste, ctx->vm);
+      csum = ip_csum_sub_even (*checksum, dport);
+      csum = ip_csum_add_even (csum, udp->dst_port);
+      csum = ip_csum_sub_even (csum, old_src.as_u32);
+      csum = ip_csum_sub_even (csum, old_dst.as_u32);
+      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]);
+      *checksum = ip_csum_fold (csum);
+    }
 
   return 0;
 }
 
 static int
-nat64_out2in_icmp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6, void *arg)
+nat64_out2in_icmp_set_cb (vlib_buffer_t * b, ip4_header_t * ip4,
+			  ip6_header_t * ip6, void *arg)
 {
   nat64_main_t *nm = &nat64_main;
   nat64_out2in_set_ctx_t *ctx = arg;
@@ -278,8 +334,8 @@ nat64_out2in_icmp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6, void *arg)
 }
 
 static int
-nat64_out2in_inner_icmp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
-				void *arg)
+nat64_out2in_inner_icmp_set_cb (vlib_buffer_t * b, ip4_header_t * ip4,
+				ip6_header_t * ip6, void *arg)
 {
   nat64_main_t *nm = &nat64_main;
   nat64_out2in_set_ctx_t *ctx = arg;
@@ -370,11 +426,15 @@ nat64_out2in_inner_icmp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
 }
 
 static int
-nat64_out2in_unk_proto_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
-			       void *arg)
+nat64_out2in_unk_proto (vlib_main_t * vm, vlib_buffer_t * p,
+			nat64_out2in_set_ctx_t * ctx)
 {
+  ip4_header_t *ip4 = vlib_buffer_get_current (p);
+  ip6_header_t *ip6;
+  ip6_frag_hdr_t *frag;
+  u32 frag_id;
+
   nat64_main_t *nm = &nat64_main;
-  nat64_out2in_set_ctx_t *ctx = arg;
   nat64_db_bib_entry_t *bibe;
   nat64_db_st_entry_t *ste;
   ip46_address_t saddr, daddr;
@@ -383,6 +443,43 @@ nat64_out2in_unk_proto_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
   u8 proto = ip4->protocol;
   nat64_db_t *db = &nm->db[ctx->thread_index];
 
+  // Deal with fragmented packets
+  u16 frag_offset = ip4_get_fragment_offset (ip4);
+  if (PREDICT_FALSE (ip4_get_fragment_more (ip4) || frag_offset))
+    {
+      ip6 =
+	(ip6_header_t *) u8_ptr_add (ip4,
+				     sizeof (*ip4) - sizeof (*ip6) -
+				     sizeof (*frag));
+      frag =
+	(ip6_frag_hdr_t *) u8_ptr_add (ip4, sizeof (*ip4) - sizeof (*frag));
+      frag_id = frag_id_4to6 (ip4->fragment_id);
+      vlib_buffer_advance (p, sizeof (*ip4) - sizeof (*ip6) - sizeof (*frag));
+    }
+  else
+    {
+      ip6 = (ip6_header_t *) (((u8 *) ip4) + sizeof (*ip4) - sizeof (*ip6));
+      vlib_buffer_advance (p, sizeof (*ip4) - sizeof (*ip6));
+      frag = NULL;
+    }
+
+  ip6->ip_version_traffic_class_and_flow_label =
+    clib_host_to_net_u32 ((6 << 28) + (ip4->tos << 20));
+  ip6->payload_length = u16_net_add (ip4->length, -sizeof (*ip4));
+  ip6->hop_limit = ip4->ttl;
+  ip6->protocol = ip4->protocol;
+
+  if (PREDICT_FALSE (frag != NULL))
+    {
+      frag->next_hdr = ip6->protocol;
+      frag->identification = frag_id;
+      frag->rsv = 0;
+      frag->fragment_offset_and_more =
+	ip6_frag_hdr_offset_and_more (frag_offset, 1);
+      ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
+      ip6->payload_length = u16_net_add (ip6->payload_length, sizeof (*frag));
+    }
+
   sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
   fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 
@@ -482,7 +579,7 @@ VLIB_NODE_FN (nat64_out2in_node) (vlib_main_t * vm,
 
 	  if (PREDICT_FALSE (proto0 == ~0))
 	    {
-	      if (ip4_to_ip6 (b0, nat64_out2in_unk_proto_set_cb, &ctx0))
+	      if (nat64_out2in_unk_proto (vm, b0, &ctx0))
 		{
 		  next0 = NAT64_OUT2IN_NEXT_DROP;
 		  b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
@@ -491,13 +588,6 @@ VLIB_NODE_FN (nat64_out2in_node) (vlib_main_t * vm,
 	      goto trace0;
 	    }
 
-	  if (PREDICT_FALSE (ip4_is_fragment (ip40)))
-	    {
-	      next0 = NAT64_OUT2IN_NEXT_REASS;
-	      fragments++;
-	      goto trace0;
-	    }
-
 	  if (proto0 == SNAT_PROTOCOL_ICMP)
 	    {
 	      icmp_packets++;
@@ -517,7 +607,7 @@ VLIB_NODE_FN (nat64_out2in_node) (vlib_main_t * vm,
 	      else
 		udp_packets++;
 
-	      if (ip4_to_ip6_tcp_udp (b0, nat64_out2in_tcp_udp_set_cb, &ctx0))
+	      if (nat64_out2in_tcp_udp (vm, b0, &ctx0))
 		{
 		  udp0 = ip4_next_header (ip40);
 		  /*
@@ -587,7 +677,6 @@ VLIB_REGISTER_NODE (nat64_out2in_node) = {
     [NAT64_OUT2IN_NEXT_DROP] = "error-drop",
     [NAT64_OUT2IN_NEXT_IP6_LOOKUP] = "ip6-lookup",
     [NAT64_OUT2IN_NEXT_IP4_LOOKUP] = "ip4-lookup",
-    [NAT64_OUT2IN_NEXT_REASS] = "nat64-out2in-reass",
   },
 };
 /* *INDENT-ON* */
@@ -602,350 +691,6 @@ typedef struct nat64_out2in_frag_set_ctx_t_
   u8 first_frag;
 } nat64_out2in_frag_set_ctx_t;
 
-static int
-nat64_out2in_frag_set_cb (ip4_header_t * ip4, ip6_header_t * ip6, void *arg)
-{
-  nat64_main_t *nm = &nat64_main;
-  nat64_out2in_frag_set_ctx_t *ctx = arg;
-  nat64_db_st_entry_t *ste;
-  nat64_db_bib_entry_t *bibe;
-  udp_header_t *udp = ip4_next_header (ip4);
-  ip_csum_t csum;
-  u16 *checksum;
-  nat64_db_t *db = &nm->db[ctx->thread_index];
-
-  ste = nat64_db_st_entry_by_index (db, ctx->proto, ctx->sess_index);
-  if (!ste)
-    return -1;
-
-  bibe = nat64_db_bib_entry_by_index (db, ctx->proto, ste->bibe_index);
-  if (!bibe)
-    return -1;
-
-  if (ctx->first_frag)
-    {
-      udp->dst_port = bibe->in_port;
-
-      if (ip4->protocol == IP_PROTOCOL_UDP)
-	{
-	  checksum = &udp->checksum;
-
-	  if (!checksum)
-	    {
-	      u16 udp_len =
-		clib_host_to_net_u16 (ip4->length) - sizeof (*ip4);
-	      csum = ip_incremental_checksum (0, udp, udp_len);
-	      csum =
-		ip_csum_with_carry (csum, clib_host_to_net_u16 (udp_len));
-	      csum =
-		ip_csum_with_carry (csum,
-				    clib_host_to_net_u16 (IP_PROTOCOL_UDP));
-	      csum = ip_csum_with_carry (csum, ste->in_r_addr.as_u64[0]);
-	      csum = ip_csum_with_carry (csum, ste->in_r_addr.as_u64[1]);
-	      csum = ip_csum_with_carry (csum, bibe->in_addr.as_u64[0]);
-	      csum = ip_csum_with_carry (csum, bibe->in_addr.as_u64[1]);
-	      *checksum = ~ip_csum_fold (csum);
-	    }
-	  else
-	    {
-	      csum = ip_csum_sub_even (*checksum, bibe->out_addr.as_u32);
-	      csum = ip_csum_sub_even (csum, ste->out_r_addr.as_u32);
-	      csum = ip_csum_sub_even (csum, bibe->out_port);
-	      csum = ip_csum_add_even (csum, ste->in_r_addr.as_u64[0]);
-	      csum = ip_csum_add_even (csum, ste->in_r_addr.as_u64[1]);
-	      csum = ip_csum_add_even (csum, bibe->in_addr.as_u64[0]);
-	      csum = ip_csum_add_even (csum, bibe->in_addr.as_u64[1]);
-	      csum = ip_csum_add_even (csum, bibe->in_port);
-	      *checksum = ip_csum_fold (csum);
-	    }
-	}
-      else
-	{
-	  tcp_header_t *tcp = ip4_next_header (ip4);
-	  nat64_tcp_session_set_state (ste, tcp, 0);
-	  checksum = &tcp->checksum;
-	  csum = ip_csum_sub_even (*checksum, bibe->out_addr.as_u32);
-	  csum = ip_csum_sub_even (csum, ste->out_r_addr.as_u32);
-	  csum = ip_csum_sub_even (csum, bibe->out_port);
-	  csum = ip_csum_add_even (csum, ste->in_r_addr.as_u64[0]);
-	  csum = ip_csum_add_even (csum, ste->in_r_addr.as_u64[1]);
-	  csum = ip_csum_add_even (csum, bibe->in_addr.as_u64[0]);
-	  csum = ip_csum_add_even (csum, bibe->in_addr.as_u64[1]);
-	  csum = ip_csum_add_even (csum, bibe->in_port);
-	  *checksum = ip_csum_fold (csum);
-	}
-
-    }
-
-  ip6->src_address.as_u64[0] = ste->in_r_addr.as_u64[0];
-  ip6->src_address.as_u64[1] = ste->in_r_addr.as_u64[1];
-
-  ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
-  ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
-
-  vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
-
-  nat64_session_reset_timeout (ste, ctx->vm);
-
-  return 0;
-}
-
-VLIB_NODE_FN (nat64_out2in_reass_node) (vlib_main_t * vm,
-					vlib_node_runtime_t * node,
-					vlib_frame_t * frame)
-{
-  u32 n_left_from, *from, *to_next;
-  nat64_out2in_next_t next_index;
-  u32 pkts_processed = 0, cached_fragments = 0;
-  u32 *fragments_to_drop = 0;
-  u32 *fragments_to_loopback = 0;
-  nat64_main_t *nm = &nat64_main;
-  u32 thread_index = vm->thread_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 *ip40;
-	  u8 cached0 = 0;
-	  u32 sw_if_index0, fib_index0;
-	  udp_header_t *udp0;
-	  nat_reass_ip4_t *reass0;
-	  ip46_address_t saddr0, daddr0;
-	  nat64_db_st_entry_t *ste0;
-	  nat64_db_bib_entry_t *bibe0;
-	  ip6_address_t ip6_saddr0;
-	  nat64_out2in_frag_set_ctx_t ctx0;
-	  nat64_db_t *db = &nm->db[thread_index];
-
-	  /* 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 = NAT64_OUT2IN_NEXT_IP6_LOOKUP;
-
-	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
-	  fib_index0 =
-	    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
-						 sw_if_index0);
-
-	  ctx0.thread_index = thread_index;
-
-	  if (PREDICT_FALSE (nat_reass_is_drop_frag (1)))
-	    {
-	      next0 = NAT64_OUT2IN_NEXT_DROP;
-	      b0->error = node->errors[NAT64_OUT2IN_ERROR_DROP_FRAGMENT];
-	      goto trace0;
-	    }
-
-	  ip40 = vlib_buffer_get_current (b0);
-
-	  if (PREDICT_FALSE (!(ip40->protocol == IP_PROTOCOL_TCP
-			       || ip40->protocol == IP_PROTOCOL_UDP)))
-	    {
-	      next0 = NAT64_OUT2IN_NEXT_DROP;
-	      b0->error = node->errors[NAT64_OUT2IN_ERROR_DROP_FRAGMENT];
-	      goto trace0;
-	    }
-
-	  udp0 = ip4_next_header (ip40);
-
-	  reass0 = nat_ip4_reass_find_or_create (ip40->src_address,
-						 ip40->dst_address,
-						 ip40->fragment_id,
-						 ip40->protocol,
-						 1, &fragments_to_drop);
-
-	  if (PREDICT_FALSE (!reass0))
-	    {
-	      next0 = NAT64_OUT2IN_NEXT_DROP;
-	      b0->error = node->errors[NAT64_OUT2IN_ERROR_MAX_REASS];
-	      goto trace0;
-	    }
-
-	  if (PREDICT_FALSE (ip4_is_first_fragment (ip40)))
-	    {
-	      ctx0.first_frag = 1;
-
-	      clib_memset (&saddr0, 0, sizeof (saddr0));
-	      saddr0.ip4.as_u32 = ip40->src_address.as_u32;
-	      clib_memset (&daddr0, 0, sizeof (daddr0));
-	      daddr0.ip4.as_u32 = ip40->dst_address.as_u32;
-
-	      ste0 =
-		nat64_db_st_entry_find (db, &daddr0, &saddr0,
-					udp0->dst_port, udp0->src_port,
-					ip40->protocol, fib_index0, 0);
-	      if (!ste0)
-		{
-		  bibe0 =
-		    nat64_db_bib_entry_find (db, &daddr0, udp0->dst_port,
-					     ip40->protocol, fib_index0, 0);
-		  if (!bibe0)
-		    {
-		      next0 = NAT64_OUT2IN_NEXT_DROP;
-		      b0->error =
-			node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
-		      goto trace0;
-		    }
-
-		  nat64_compose_ip6 (&ip6_saddr0, &ip40->src_address,
-				     bibe0->fib_index);
-		  ste0 =
-		    nat64_db_st_entry_create (thread_index,
-					      db, bibe0, &ip6_saddr0,
-					      &saddr0.ip4, udp0->src_port);
-
-		  if (!ste0)
-		    {
-		      next0 = NAT64_OUT2IN_NEXT_DROP;
-		      b0->error =
-			node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
-		      goto trace0;
-		    }
-
-		  vlib_set_simple_counter (&nm->total_sessions, thread_index,
-					   0, db->st.st_entries_num);
-		}
-	      reass0->sess_index = nat64_db_st_entry_get_index (db, ste0);
-	      reass0->thread_index = thread_index;
-
-	      nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
-	    }
-	  else
-	    {
-	      ctx0.first_frag = 0;
-
-	      if (PREDICT_FALSE (reass0->sess_index == (u32) ~ 0))
-		{
-		  if (nat_ip4_reass_add_fragment
-		      (thread_index, reass0, bi0, &fragments_to_drop))
-		    {
-		      b0->error = node->errors[NAT64_OUT2IN_ERROR_MAX_FRAG];
-		      next0 = NAT64_OUT2IN_NEXT_DROP;
-		      goto trace0;
-		    }
-		  cached0 = 1;
-		  goto trace0;
-		}
-	    }
-
-	  ctx0.sess_index = reass0->sess_index;
-	  ctx0.proto = ip40->protocol;
-	  ctx0.vm = vm;
-	  ctx0.b = b0;
-
-	  if (ip4_to_ip6_fragmented (b0, nat64_out2in_frag_set_cb, &ctx0))
-	    {
-	      next0 = NAT64_OUT2IN_NEXT_DROP;
-	      b0->error = node->errors[NAT64_OUT2IN_ERROR_UNKNOWN];
-	      goto trace0;
-	    }
-
-	trace0:
-	  if (PREDICT_FALSE
-	      ((node->flags & VLIB_NODE_FLAG_TRACE)
-	       && (b0->flags & VLIB_BUFFER_IS_TRACED)))
-	    {
-	      nat64_out2in_reass_trace_t *t =
-		vlib_add_trace (vm, node, b0, sizeof (*t));
-	      t->cached = cached0;
-	      t->sw_if_index = sw_if_index0;
-	      t->next_index = next0;
-	    }
-
-	  if (cached0)
-	    {
-	      n_left_to_next++;
-	      to_next--;
-	      cached_fragments++;
-	    }
-	  else
-	    {
-	      pkts_processed += next0 != NAT64_OUT2IN_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);
-	    }
-
-	  if (n_left_from == 0 && vec_len (fragments_to_loopback))
-	    {
-	      from = vlib_frame_vector_args (frame);
-	      u32 len = vec_len (fragments_to_loopback);
-	      if (len <= VLIB_FRAME_SIZE)
-		{
-		  clib_memcpy_fast (from, fragments_to_loopback,
-				    sizeof (u32) * len);
-		  n_left_from = len;
-		  vec_reset_length (fragments_to_loopback);
-		}
-	      else
-		{
-		  clib_memcpy_fast (from, fragments_to_loopback +
-				    (len - VLIB_FRAME_SIZE),
-				    sizeof (u32) * VLIB_FRAME_SIZE);
-		  n_left_from = VLIB_FRAME_SIZE;
-		  _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
-		}
-	    }
-	}
-
-      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
-    }
-
-  vlib_node_increment_counter (vm, nm->out2in_reass_node_index,
-			       NAT64_OUT2IN_ERROR_PROCESSED_FRAGMENTS,
-			       pkts_processed);
-  vlib_node_increment_counter (vm, nm->out2in_reass_node_index,
-			       NAT64_OUT2IN_ERROR_CACHED_FRAGMENTS,
-			       cached_fragments);
-
-  nat_send_all_to_node (vm, fragments_to_drop, node,
-			&node->errors[NAT64_OUT2IN_ERROR_DROP_FRAGMENT],
-			NAT64_OUT2IN_NEXT_DROP);
-
-  vec_free (fragments_to_drop);
-  vec_free (fragments_to_loopback);
-  return frame->n_vectors;
-}
-
-/* *INDENT-OFF* */
-VLIB_REGISTER_NODE (nat64_out2in_reass_node) = {
-  .name = "nat64-out2in-reass",
-  .vector_size = sizeof (u32),
-  .format_trace = format_nat64_out2in_reass_trace,
-  .type = VLIB_NODE_TYPE_INTERNAL,
-  .n_errors = ARRAY_LEN (nat64_out2in_error_strings),
-  .error_strings = nat64_out2in_error_strings,
-  .n_next_nodes = NAT64_OUT2IN_N_NEXT,
-  /* edit / add dispositions here */
-  .next_nodes = {
-    [NAT64_OUT2IN_NEXT_DROP] = "error-drop",
-    [NAT64_OUT2IN_NEXT_IP6_LOOKUP] = "ip6-lookup",
-    [NAT64_OUT2IN_NEXT_IP4_LOOKUP] = "ip4-lookup",
-    [NAT64_OUT2IN_NEXT_REASS] = "nat64-out2in-reass",
-  },
-};
-/* *INDENT-ON* */
-
 #define foreach_nat64_out2in_handoff_error                       \
 _(CONGESTION_DROP, "congestion drop")                            \
 _(SAME_WORKER, "same worker")                                    \
@@ -1010,7 +755,7 @@ VLIB_NODE_FN (nat64_out2in_handoff_node) (vlib_main_t * vm,
       ip4_header_t *ip0;
 
       ip0 = vlib_buffer_get_current (b[0]);
-      ti[0] = nat64_get_worker_out2in (ip0);
+      ti[0] = nat64_get_worker_out2in (b[0], ip0);
 
       if (ti[0] != thread_index)
 	do_handoff++;