NAT64: Move IPv6-IPv4 virtual reassembly code from MAP-T to common library (VPP-708)

Change-Id: I9ad636f80bf109ffac9ca1b6d80d5f2c31f2076a
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 164 insertions, 642 deletions

diff --git a/src/vnet/map/ip6_map_t.c b/src/vnet/map/ip6_map_t.c
index 99151678a5a..b173bb2ad01 100644
--- a/src/vnet/map/ip6_map_t.c
+++ b/src/vnet/map/ip6_map_t.c
@@ -15,6 +15,8 @@
 #include "map.h"
 
 #include "../ip/ip_frag.h"
+#include <vnet/ip/ip6_to_ip4.h>
+#include <vnet/ip/ip4_to_ip6.h>
 
 #define IP6_MAP_T_DUAL_LOOP
 
@@ -94,347 +96,55 @@ ip6_map_fragment_get (ip6_header_t * ip6, ip6_frag_hdr_t * frag,
   return ret;
 }
 
-static_always_inline u8
-ip6_translate_tos (const ip6_header_t * ip6)
+typedef struct
 {
-#ifdef IP6_MAP_T_OVERRIDE_TOS
-  return IP6_MAP_T_OVERRIDE_TOS;
-#else
-  return (clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label)
-	  & 0x0ff00000) >> 20;
-#endif
-}
-
-//TODO: Find right place in memory for that
-/* *INDENT-OFF* */
-static u8 icmp6_to_icmp_updater_pointer_table[] =
-  { 0, 1, ~0, ~0,
-    2, 2, 9, 8,
-    12, 12, 12, 12,
-    12, 12, 12, 12,
-    12, 12, 12, 12,
-    12, 12, 12, 12,
-    24, 24, 24, 24,
-    24, 24, 24, 24,
-    24, 24, 24, 24,
-    24, 24, 24, 24
-  };
-/* *INDENT-ON* */
-
-static_always_inline int
-ip6_icmp_to_icmp6_in_place (icmp46_header_t * icmp, u32 icmp_len,
-			    i32 * sender_port, ip6_header_t ** inner_ip6)
-{
-  *inner_ip6 = NULL;
-  switch (icmp->type)
-    {
-    case ICMP6_echo_request:
-      *sender_port = ((u16 *) icmp)[2];
-      icmp->type = ICMP4_echo_request;
-      break;
-    case ICMP6_echo_reply:
-      *sender_port = ((u16 *) icmp)[2];
-      icmp->type = ICMP4_echo_reply;
-      break;
-    case ICMP6_destination_unreachable:
-      *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8);
-      *sender_port = ip6_get_port (*inner_ip6, MAP_RECEIVER, icmp_len);
-
-      switch (icmp->code)
-	{
-	case ICMP6_destination_unreachable_no_route_to_destination:	//0
-	case ICMP6_destination_unreachable_beyond_scope_of_source_address:	//2
-	case ICMP6_destination_unreachable_address_unreachable:	//3
-	  icmp->type = ICMP4_destination_unreachable;
-	  icmp->code =
-	    ICMP4_destination_unreachable_destination_unreachable_host;
-	  break;
-	case ICMP6_destination_unreachable_destination_administratively_prohibited:	//1
-	  icmp->type =
-	    ICMP4_destination_unreachable;
-	  icmp->code =
-	    ICMP4_destination_unreachable_communication_administratively_prohibited;
-	  break;
-	case ICMP6_destination_unreachable_port_unreachable:
-	  icmp->type = ICMP4_destination_unreachable;
-	  icmp->code = ICMP4_destination_unreachable_port_unreachable;
-	  break;
-	default:
-	  return -1;
-	}
-      break;
-    case ICMP6_packet_too_big:
-      *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8);
-      *sender_port = ip6_get_port (*inner_ip6, MAP_RECEIVER, icmp_len);
-
-      icmp->type = ICMP4_destination_unreachable;
-      icmp->code = 4;
-      {
-	u32 advertised_mtu = clib_net_to_host_u32 (*((u32 *) (icmp + 1)));
-	advertised_mtu -= 20;
-	//FIXME: = minimum(advertised MTU-20, MTU_of_IPv4_nexthop, (MTU_of_IPv6_nexthop)-20)
-	((u16 *) (icmp))[3] = clib_host_to_net_u16 (advertised_mtu);
-      }
-      break;
-
-    case ICMP6_time_exceeded:
-      *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8);
-      *sender_port = ip6_get_port (*inner_ip6, MAP_RECEIVER, icmp_len);
-
-      icmp->type = ICMP4_time_exceeded;
-      break;
-
-    case ICMP6_parameter_problem:
-      *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8);
-      *sender_port = ip6_get_port (*inner_ip6, MAP_RECEIVER, icmp_len);
-
-      switch (icmp->code)
-	{
-	case ICMP6_parameter_problem_erroneous_header_field:
-	  icmp->type = ICMP4_parameter_problem;
-	  icmp->code = ICMP4_parameter_problem_pointer_indicates_error;
-	  u32 pointer = clib_net_to_host_u32 (*((u32 *) (icmp + 1)));
-	  if (pointer >= 40)
-	    return -1;
-
-	  ((u8 *) (icmp + 1))[0] =
-	    icmp6_to_icmp_updater_pointer_table[pointer];
-	  break;
-	case ICMP6_parameter_problem_unrecognized_next_header:
-	  icmp->type = ICMP4_destination_unreachable;
-	  icmp->code = ICMP4_destination_unreachable_port_unreachable;
-	  break;
-	case ICMP6_parameter_problem_unrecognized_option:
-	default:
-	  return -1;
-	}
-      break;
-    default:
-      return -1;
-      break;
-    }
-  return 0;
-}
+  map_domain_t *d;
+  u16 sender_port;
+} icmp6_to_icmp_ctx_t;
 
-static_always_inline void
-_ip6_map_t_icmp (map_domain_t * d, vlib_buffer_t * p, u8 * error)
+static int
+ip6_to_ip4_set_icmp_cb (ip6_header_t * ip6, ip4_header_t * ip4, void *arg)
 {
-  ip6_header_t *ip6, *inner_ip6;
-  ip4_header_t *ip4, *inner_ip4;
-  u32 ip6_pay_len;
-  icmp46_header_t *icmp;
-  i32 sender_port;
-  ip_csum_t csum;
-  u32 ip4_sadr, inner_ip4_dadr;
-
-  ip6 = vlib_buffer_get_current (p);
-  ip6_pay_len = clib_net_to_host_u16 (ip6->payload_length);
-  icmp = (icmp46_header_t *) (ip6 + 1);
-  ASSERT (ip6_pay_len + sizeof (*ip6) <= p->current_length);
-
-  if (ip6->protocol != IP_PROTOCOL_ICMP6)
-    {
-      //No extensions headers allowed here
-      //TODO: SR header
-      *error = MAP_ERROR_MALFORMED;
-      return;
-    }
-
-  //There are no fragmented ICMP messages, so no extension header for now
-
-  if (ip6_icmp_to_icmp6_in_place
-      (icmp, ip6_pay_len, &sender_port, &inner_ip6))
-    {
-      //TODO: In case of 1:1 mapping it is not necessary to have the sender port
-      *error = MAP_ERROR_ICMP;
-      return;
-    }
-
-  if (sender_port < 0)
-    {
-      // In case of 1:1 mapping, we don't care about the port
-      if (d->ea_bits_len == 0 && d->rules)
-	{
-	  sender_port = 0;
-	}
-      else
-	{
-	  *error = MAP_ERROR_ICMP;
-	  return;
-	}
-    }
+  icmp6_to_icmp_ctx_t *ctx = arg;
+  u32 ip4_sadr;
 
   //Security check
   //Note that this prevents an intermediate IPv6 router from answering the request
   ip4_sadr = map_get_ip4 (&ip6->src_address);
-  if (ip6->src_address.as_u64[0] != map_get_pfx_net (d, ip4_sadr, sender_port)
-      || ip6->src_address.as_u64[1] != map_get_sfx_net (d, ip4_sadr,
-							sender_port))
-    {
-      *error = MAP_ERROR_SEC_CHECK;
-      return;
-    }
-
-  if (inner_ip6)
-    {
-      u16 *inner_L4_checksum, inner_l4_offset, inner_frag_offset,
-	inner_frag_id;
-      u8 *inner_l4, inner_protocol;
-
-      //We have two headers to translate
-      //   FROM
-      //   [   IPv6   ]<- ext ->[IC][   IPv6   ]<- ext ->[L4 header ...
-      // Handled cases:
-      //                     [   IPv6   ][IC][   IPv6   ][L4 header ...
-      //                 [   IPv6   ][IC][   IPv6   ][Fr][L4 header ...
-      //    TO
-      //                               [ IPv4][IC][ IPv4][L4 header ...
-
-      //TODO: This was already done deep in ip6_icmp_to_icmp6_in_place
-      //We shouldn't have to do it again
-      if (ip6_parse (inner_ip6, ip6_pay_len - 8,
-		     &inner_protocol, &inner_l4_offset, &inner_frag_offset))
-	{
-	  *error = MAP_ERROR_MALFORMED;
-	  return;
-	}
-
-      inner_l4 = u8_ptr_add (inner_ip6, inner_l4_offset);
-      inner_ip4 =
-	(ip4_header_t *) u8_ptr_add (inner_l4, -sizeof (*inner_ip4));
-      if (inner_frag_offset)
-	{
-	  ip6_frag_hdr_t *inner_frag =
-	    (ip6_frag_hdr_t *) u8_ptr_add (inner_ip6, inner_frag_offset);
-	  inner_frag_id = frag_id_6to4 (inner_frag->identification);
-	}
-      else
-	{
-	  inner_frag_id = 0;
-	}
-
-      //Do the translation of the inner packet
-      if (inner_protocol == IP_PROTOCOL_TCP)
-	{
-	  inner_L4_checksum = (u16 *) u8_ptr_add (inner_l4, 16);
-	}
-      else if (inner_protocol == IP_PROTOCOL_UDP)
-	{
-	  inner_L4_checksum = (u16 *) u8_ptr_add (inner_l4, 6);
-	}
-      else if (inner_protocol == IP_PROTOCOL_ICMP6)
-	{
-	  icmp46_header_t *inner_icmp = (icmp46_header_t *) inner_l4;
-	  csum = inner_icmp->checksum;
-	  csum = ip_csum_sub_even (csum, *((u16 *) inner_icmp));
-	  //It cannot be of a different type as ip6_icmp_to_icmp6_in_place succeeded
-	  inner_icmp->type = (inner_icmp->type == ICMP6_echo_request) ?
-	    ICMP4_echo_request : ICMP4_echo_reply;
-	  csum = ip_csum_add_even (csum, *((u16 *) inner_icmp));
-	  inner_icmp->checksum = ip_csum_fold (csum);
-	  inner_protocol = IP_PROTOCOL_ICMP;	//Will be copied to ip6 later
-	  inner_L4_checksum = &inner_icmp->checksum;
-	}
-      else
-	{
-	  *error = MAP_ERROR_BAD_PROTOCOL;
-	  return;
-	}
-
-      csum = *inner_L4_checksum;
-      csum = ip_csum_sub_even (csum, 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]);
-
-      //Sanity check of the outer destination address
-      if (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])
-	{
-	  *error = MAP_ERROR_SEC_CHECK;
-	  return;
-	}
-
-      //Security check of inner packet
-      inner_ip4_dadr = map_get_ip4 (&inner_ip6->dst_address);
-      if (inner_ip6->dst_address.as_u64[0] !=
-	  map_get_pfx_net (d, inner_ip4_dadr, sender_port)
-	  || inner_ip6->dst_address.as_u64[1] != map_get_sfx_net (d,
-								  inner_ip4_dadr,
-								  sender_port))
-	{
-	  *error = MAP_ERROR_SEC_CHECK;
-	  return;
-	}
+  if (ip6->src_address.as_u64[0] !=
+      map_get_pfx_net (ctx->d, ip4_sadr, ctx->sender_port)
+      || ip6->src_address.as_u64[1] != map_get_sfx_net (ctx->d, ip4_sadr,
+							ctx->sender_port))
+    return -1;
+
+  ip4->dst_address.as_u32 =
+    ip6_map_t_embedded_address (ctx->d, &ip6->dst_address);
+  ip4->src_address.as_u32 = ip4_sadr;
 
-      inner_ip4->dst_address.as_u32 = inner_ip4_dadr;
-      inner_ip4->src_address.as_u32 =
-	ip6_map_t_embedded_address (d, &inner_ip6->src_address);
-      inner_ip4->ip_version_and_header_length =
-	IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS;
-      inner_ip4->tos = ip6_translate_tos (inner_ip6);
-      inner_ip4->length =
-	u16_net_add (inner_ip6->payload_length,
-		     sizeof (*ip4) + sizeof (*ip6) - inner_l4_offset);
-      inner_ip4->fragment_id = inner_frag_id;
-      inner_ip4->flags_and_fragment_offset =
-	clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);
-      inner_ip4->ttl = inner_ip6->hop_limit;
-      inner_ip4->protocol = inner_protocol;
-      inner_ip4->checksum = ip4_header_checksum (inner_ip4);
-
-      if (inner_ip4->protocol == IP_PROTOCOL_ICMP)
-	{
-	  //Remove remainings of the pseudo-header in the csum
-	  csum =
-	    ip_csum_sub_even (csum, clib_host_to_net_u16 (IP_PROTOCOL_ICMP6));
-	  csum =
-	    ip_csum_sub_even (csum, inner_ip4->length - sizeof (*inner_ip4));
-	}
-      else
-	{
-	  //Update to new pseudo-header
-	  csum = ip_csum_add_even (csum, inner_ip4->src_address.as_u32);
-	  csum = ip_csum_add_even (csum, inner_ip4->dst_address.as_u32);
-	}
-      *inner_L4_checksum = ip_csum_fold (csum);
+  return 0;
+}
 
-      //Move up icmp header
-      ip4 = (ip4_header_t *) u8_ptr_add (inner_l4, -2 * sizeof (*ip4) - 8);
-      clib_memcpy (u8_ptr_add (inner_l4, -sizeof (*ip4) - 8), icmp, 8);
-      icmp = (icmp46_header_t *) u8_ptr_add (inner_l4, -sizeof (*ip4) - 8);
-    }
-  else
-    {
-      //Only one header to translate
-      ip4 = (ip4_header_t *) u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4));
-    }
-  vlib_buffer_advance (p, (u32) (((u8 *) ip4) - ((u8 *) ip6)));
+static int
+ip6_to_ip4_set_inner_icmp_cb (ip6_header_t * ip6, ip4_header_t * ip4,
+			      void *arg)
+{
+  icmp6_to_icmp_ctx_t *ctx = arg;
+  u32 inner_ip4_dadr;
+
+  //Security check of inner packet
+  inner_ip4_dadr = map_get_ip4 (&ip6->dst_address);
+  if (ip6->dst_address.as_u64[0] !=
+      map_get_pfx_net (ctx->d, inner_ip4_dadr, ctx->sender_port)
+      || ip6->dst_address.as_u64[1] != map_get_sfx_net (ctx->d,
+							inner_ip4_dadr,
+							ctx->sender_port))
+    return -1;
+
+  ip4->dst_address.as_u32 = inner_ip4_dadr;
+  ip4->src_address.as_u32 =
+    ip6_map_t_embedded_address (ctx->d, &ip6->src_address);
 
-  ip4->dst_address.as_u32 = ip6_map_t_embedded_address (d, &ip6->dst_address);
-  ip4->src_address.as_u32 = ip4_sadr;
-  ip4->ip_version_and_header_length =
-    IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS;
-  ip4->tos = ip6_translate_tos (ip6);
-  ip4->fragment_id = 0;
-  ip4->flags_and_fragment_offset = 0;
-  ip4->ttl = ip6->hop_limit;
-  ip4->protocol = IP_PROTOCOL_ICMP;
-  //TODO fix the length depending on offset length
-  ip4->length = u16_net_add (ip6->payload_length,
-			     (inner_ip6 ==
-			      NULL) ? sizeof (*ip4) : (2 * sizeof (*ip4) -
-						       sizeof (*ip6)));
-  ip4->checksum = ip4_header_checksum (ip4);
-
-  //TODO: We could do an easy diff-checksum for echo requests/replies
-  //Recompute ICMP checksum
-  icmp->checksum = 0;
-  csum =
-    ip_incremental_checksum (0, icmp,
-			     clib_net_to_host_u16 (ip4->length) -
-			     sizeof (*ip4));
-  icmp->checksum = ~ip_csum_fold (csum);
+  return 0;
 }
 
 static uword
@@ -462,6 +172,8 @@ ip6_map_t_icmp (vlib_main_t * vm,
 	  ip6_mapt_icmp_next_t next0;
 	  map_domain_t *d0;
 	  u16 len0;
+	  icmp6_to_icmp_ctx_t ctx0;
+	  ip6_header_t *ip60;
 
 	  pi0 = to_next[0] = from[0];
 	  from += 1;
@@ -472,14 +184,30 @@ ip6_map_t_icmp (vlib_main_t * vm,
 	  next0 = IP6_MAPT_ICMP_NEXT_IP4_LOOKUP;
 
 	  p0 = vlib_get_buffer (vm, pi0);
-	  len0 =
-	    clib_net_to_host_u16 (((ip6_header_t *)
-				   vlib_buffer_get_current
-				   (p0))->payload_length);
+	  ip60 = vlib_buffer_get_current (p0);
+	  len0 = clib_net_to_host_u16 (ip60->payload_length);
 	  d0 =
 	    pool_elt_at_index (map_main.domains,
 			       vnet_buffer (p0)->map_t.map_domain_index);
-	  _ip6_map_t_icmp (d0, p0, &error0);
+	  ctx0.sender_port = ip6_get_port (ip60, 0, len0);
+	  ctx0.d = d0;
+	  if (ctx0.sender_port == 0)
+	    {
+	      // In case of 1:1 mapping, we don't care about the port
+	      if (!(d0->ea_bits_len == 0 && d0->rules))
+		{
+		  error0 = MAP_ERROR_ICMP;
+		  goto err0;
+		}
+	    }
+
+	  if (icmp6_to_icmp
+	      (p0, ip6_to_ip4_set_icmp_cb, d0, ip6_to_ip4_set_inner_icmp_cb,
+	       d0))
+	    {
+	      error0 = MAP_ERROR_ICMP;
+	      goto err0;
+	    }
 
 	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
 	    {
@@ -489,7 +217,7 @@ ip6_map_t_icmp (vlib_main_t * vm,
 	      vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
 	      next0 = IP6_MAPT_ICMP_NEXT_IP4_FRAG;
 	    }
-
+	err0:
 	  if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
 	    {
 	      vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_RX,
@@ -513,6 +241,17 @@ ip6_map_t_icmp (vlib_main_t * vm,
   return frame->n_vectors;
 }
 
+static int
+ip6_to_ip4_set_cb (ip6_header_t * ip6, ip4_header_t * ip4, void *ctx)
+{
+  vlib_buffer_t *p = ctx;
+
+  ip4->dst_address.as_u32 = vnet_buffer (p)->map_t.v6.daddr;
+  ip4->src_address.as_u32 = vnet_buffer (p)->map_t.v6.saddr;
+
+  return 0;
+}
+
 static uword
 ip6_map_t_fragmented (vlib_main_t * vm,
 		      vlib_node_runtime_t * node, vlib_frame_t * frame)
@@ -521,6 +260,8 @@ ip6_map_t_fragmented (vlib_main_t * vm,
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
   next_index = node->cached_next_index;
+  vlib_node_runtime_t *error_node =
+    vlib_node_get_runtime (vm, ip6_map_t_fragmented_node.index);
 
   while (n_left_from > 0)
     {
@@ -531,11 +272,6 @@ ip6_map_t_fragmented (vlib_main_t * vm,
 	{
 	  u32 pi0, pi1;
 	  vlib_buffer_t *p0, *p1;
-	  ip6_header_t *ip60, *ip61;
-	  ip6_frag_hdr_t *frag0, *frag1;
-	  ip4_header_t *ip40, *ip41;
-	  u16 frag_id0, frag_offset0, frag_id1, frag_offset1;
-	  u8 frag_more0, frag_more1;
 	  u32 next0, next1;
 
 	  pi0 = to_next[0] = from[0];
@@ -549,94 +285,41 @@ ip6_map_t_fragmented (vlib_main_t * vm,
 	  next1 = IP6_MAPT_TCP_UDP_NEXT_IP4_LOOKUP;
 	  p0 = vlib_get_buffer (vm, pi0);
 	  p1 = vlib_get_buffer (vm, pi1);
-	  ip60 = vlib_buffer_get_current (p0);
-	  ip61 = vlib_buffer_get_current (p1);
-	  frag0 =
-	    (ip6_frag_hdr_t *) u8_ptr_add (ip60,
-					   vnet_buffer (p0)->map_t.
-					   v6.frag_offset);
-	  frag1 =
-	    (ip6_frag_hdr_t *) u8_ptr_add (ip61,
-					   vnet_buffer (p1)->map_t.
-					   v6.frag_offset);
-	  ip40 =
-	    (ip4_header_t *) u8_ptr_add (ip60,
-					 vnet_buffer (p0)->map_t.
-					 v6.l4_offset - sizeof (*ip40));
-	  ip41 =
-	    (ip4_header_t *) u8_ptr_add (ip61,
-					 vnet_buffer (p1)->map_t.
-					 v6.l4_offset - sizeof (*ip40));
-	  vlib_buffer_advance (p0,
-			       vnet_buffer (p0)->map_t.v6.l4_offset -
-			       sizeof (*ip40));
-	  vlib_buffer_advance (p1,
-			       vnet_buffer (p1)->map_t.v6.l4_offset -
-			       sizeof (*ip40));
-
-	  frag_id0 = frag_id_6to4 (frag0->identification);
-	  frag_id1 = frag_id_6to4 (frag1->identification);
-	  frag_more0 = ip6_frag_hdr_more (frag0);
-	  frag_more1 = ip6_frag_hdr_more (frag1);
-	  frag_offset0 = ip6_frag_hdr_offset (frag0);
-	  frag_offset1 = ip6_frag_hdr_offset (frag1);
-
-	  ip40->dst_address.as_u32 = vnet_buffer (p0)->map_t.v6.daddr;
-	  ip41->dst_address.as_u32 = vnet_buffer (p1)->map_t.v6.daddr;
-	  ip40->src_address.as_u32 = vnet_buffer (p0)->map_t.v6.saddr;
-	  ip41->src_address.as_u32 = vnet_buffer (p1)->map_t.v6.saddr;
-	  ip40->ip_version_and_header_length =
-	    IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS;
-	  ip41->ip_version_and_header_length =
-	    IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS;
-	  ip40->tos = ip6_translate_tos (ip60);
-	  ip41->tos = ip6_translate_tos (ip61);
-	  ip40->length = u16_net_add (ip60->payload_length,
-				      sizeof (*ip40) -
-				      vnet_buffer (p0)->map_t.v6.l4_offset +
-				      sizeof (*ip60));
-	  ip41->length =
-	    u16_net_add (ip61->payload_length,
-			 sizeof (*ip40) -
-			 vnet_buffer (p1)->map_t.v6.l4_offset +
-			 sizeof (*ip60));
-	  ip40->fragment_id = frag_id0;
-	  ip41->fragment_id = frag_id1;
-	  ip40->flags_and_fragment_offset =
-	    clib_host_to_net_u16 (frag_offset0 |
-				  (frag_more0 ? IP4_HEADER_FLAG_MORE_FRAGMENTS
-				   : 0));
-	  ip41->flags_and_fragment_offset =
-	    clib_host_to_net_u16 (frag_offset1 |
-				  (frag_more1 ? IP4_HEADER_FLAG_MORE_FRAGMENTS
-				   : 0));
-	  ip40->ttl = ip60->hop_limit;
-	  ip41->ttl = ip61->hop_limit;
-	  ip40->protocol =
-	    (vnet_buffer (p0)->map_t.v6.l4_protocol ==
-	     IP_PROTOCOL_ICMP6) ? IP_PROTOCOL_ICMP : vnet_buffer (p0)->
-	    map_t.v6.l4_protocol;
-	  ip41->protocol =
-	    (vnet_buffer (p1)->map_t.v6.l4_protocol ==
-	     IP_PROTOCOL_ICMP6) ? IP_PROTOCOL_ICMP : vnet_buffer (p1)->
-	    map_t.v6.l4_protocol;
-	  ip40->checksum = ip4_header_checksum (ip40);
-	  ip41->checksum = ip4_header_checksum (ip41);
 
-	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+	  if (ip6_to_ip4_fragmented (p0, ip6_to_ip4_set_cb, p0))
 	    {
-	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.header_offset = 0;
-	      vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
-	      next0 = IP6_MAPT_FRAGMENTED_NEXT_IP4_FRAG;
+	      p0->error = error_node->errors[MAP_ERROR_FRAGMENT_DROPPED];
+	      next0 = IP6_MAPT_FRAGMENTED_NEXT_DROP;
+	    }
+	  else
+	    {
+	      if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
+		  vnet_buffer (p0)->ip_frag.header_offset = 0;
+		  vnet_buffer (p0)->ip_frag.next_index =
+		    IP4_FRAG_NEXT_IP4_LOOKUP;
+		  next0 = IP6_MAPT_FRAGMENTED_NEXT_IP4_FRAG;
+		}
 	    }
 
-	  if (vnet_buffer (p1)->map_t.mtu < p1->current_length)
+	  if (ip6_to_ip4_fragmented (p1, ip6_to_ip4_set_cb, p1))
 	    {
-	      vnet_buffer (p1)->ip_frag.mtu = vnet_buffer (p1)->map_t.mtu;
-	      vnet_buffer (p1)->ip_frag.header_offset = 0;
-	      vnet_buffer (p1)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
-	      next1 = IP6_MAPT_FRAGMENTED_NEXT_IP4_FRAG;
+	      p1->error = error_node->errors[MAP_ERROR_FRAGMENT_DROPPED];
+	      next1 = IP6_MAPT_FRAGMENTED_NEXT_DROP;
+	    }
+	  else
+	    {
+	      if (vnet_buffer (p1)->map_t.mtu < p1->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p1)->ip_frag.mtu = vnet_buffer (p1)->map_t.mtu;
+		  vnet_buffer (p1)->ip_frag.header_offset = 0;
+		  vnet_buffer (p1)->ip_frag.next_index =
+		    IP4_FRAG_NEXT_IP4_LOOKUP;
+		  next1 = IP6_MAPT_FRAGMENTED_NEXT_IP4_FRAG;
+		}
 	    }
 
 	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
@@ -649,12 +332,6 @@ ip6_map_t_fragmented (vlib_main_t * vm,
 	{
 	  u32 pi0;
 	  vlib_buffer_t *p0;
-	  ip6_header_t *ip60;
-	  ip6_frag_hdr_t *frag0;
-	  ip4_header_t *ip40;
-	  u16 frag_id0;
-	  u8 frag_more0;
-	  u16 frag_offset0;
 	  u32 next0;
 
 	  pi0 = to_next[0] = from[0];
@@ -665,51 +342,23 @@ ip6_map_t_fragmented (vlib_main_t * vm,
 
 	  next0 = IP6_MAPT_TCP_UDP_NEXT_IP4_LOOKUP;
 	  p0 = vlib_get_buffer (vm, pi0);
-	  ip60 = vlib_buffer_get_current (p0);
-	  frag0 =
-	    (ip6_frag_hdr_t *) u8_ptr_add (ip60,
-					   vnet_buffer (p0)->map_t.
-					   v6.frag_offset);
-	  ip40 =
-	    (ip4_header_t *) u8_ptr_add (ip60,
-					 vnet_buffer (p0)->map_t.
-					 v6.l4_offset - sizeof (*ip40));
-	  vlib_buffer_advance (p0,
-			       vnet_buffer (p0)->map_t.v6.l4_offset -
-			       sizeof (*ip40));
-
-	  frag_id0 = frag_id_6to4 (frag0->identification);
-	  frag_more0 = ip6_frag_hdr_more (frag0);
-	  frag_offset0 = ip6_frag_hdr_offset (frag0);
-
-	  ip40->dst_address.as_u32 = vnet_buffer (p0)->map_t.v6.daddr;
-	  ip40->src_address.as_u32 = vnet_buffer (p0)->map_t.v6.saddr;
-	  ip40->ip_version_and_header_length =
-	    IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS;
-	  ip40->tos = ip6_translate_tos (ip60);
-	  ip40->length = u16_net_add (ip60->payload_length,
-				      sizeof (*ip40) -
-				      vnet_buffer (p0)->map_t.v6.l4_offset +
-				      sizeof (*ip60));
-	  ip40->fragment_id = frag_id0;
-	  ip40->flags_and_fragment_offset =
-	    clib_host_to_net_u16 (frag_offset0 |
-				  (frag_more0 ? IP4_HEADER_FLAG_MORE_FRAGMENTS
-				   : 0));
-	  ip40->ttl = ip60->hop_limit;
-	  ip40->protocol =
-	    (vnet_buffer (p0)->map_t.v6.l4_protocol ==
-	     IP_PROTOCOL_ICMP6) ? IP_PROTOCOL_ICMP : vnet_buffer (p0)->
-	    map_t.v6.l4_protocol;
-	  ip40->checksum = ip4_header_checksum (ip40);
 
-	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+	  if (ip6_to_ip4_fragmented (p0, ip6_to_ip4_set_cb, p0))
 	    {
-	      //Send to fragmentation node if necessary
-	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.header_offset = 0;
-	      vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
-	      next0 = IP6_MAPT_FRAGMENTED_NEXT_IP4_FRAG;
+	      p0->error = error_node->errors[MAP_ERROR_FRAGMENT_DROPPED];
+	      next0 = IP6_MAPT_FRAGMENTED_NEXT_DROP;
+	    }
+	  else
+	    {
+	      if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
+		  vnet_buffer (p0)->ip_frag.header_offset = 0;
+		  vnet_buffer (p0)->ip_frag.next_index =
+		    IP4_FRAG_NEXT_IP4_LOOKUP;
+		  next0 = IP6_MAPT_FRAGMENTED_NEXT_IP4_FRAG;
+		}
 	    }
 
 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
@@ -726,6 +375,9 @@ ip6_map_t_tcp_udp (vlib_main_t * vm,
 		   vlib_node_runtime_t * node, vlib_frame_t * frame)
 {
   u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
+  vlib_node_runtime_t *error_node =
+    vlib_node_get_runtime (vm, ip6_map_t_tcp_udp_node.index);
+
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
   next_index = node->cached_next_index;
@@ -738,11 +390,6 @@ ip6_map_t_tcp_udp (vlib_main_t * vm,
 	{
 	  u32 pi0, pi1;
 	  vlib_buffer_t *p0, *p1;
-	  ip6_header_t *ip60, *ip61;
-	  ip_csum_t csum0, csum1;
-	  ip4_header_t *ip40, *ip41;
-	  u16 fragment_id0, flags0, *checksum0,
-	    fragment_id1, flags1, *checksum1;
 	  ip6_mapt_tcp_udp_next_t next0, next1;
 
 	  pi0 = to_next[0] = from[0];
@@ -756,118 +403,41 @@ ip6_map_t_tcp_udp (vlib_main_t * vm,
 
 	  p0 = vlib_get_buffer (vm, pi0);
 	  p1 = vlib_get_buffer (vm, pi1);
-	  ip60 = vlib_buffer_get_current (p0);
-	  ip61 = vlib_buffer_get_current (p1);
-	  ip40 =
-	    (ip4_header_t *) u8_ptr_add (ip60,
-					 vnet_buffer (p0)->map_t.
-					 v6.l4_offset - sizeof (*ip40));
-	  ip41 =
-	    (ip4_header_t *) u8_ptr_add (ip61,
-					 vnet_buffer (p1)->map_t.
-					 v6.l4_offset - sizeof (*ip40));
-	  vlib_buffer_advance (p0,
-			       vnet_buffer (p0)->map_t.v6.l4_offset -
-			       sizeof (*ip40));
-	  vlib_buffer_advance (p1,
-			       vnet_buffer (p1)->map_t.v6.l4_offset -
-			       sizeof (*ip40));
-	  checksum0 =
-	    (u16 *) u8_ptr_add (ip60,
-				vnet_buffer (p0)->map_t.checksum_offset);
-	  checksum1 =
-	    (u16 *) u8_ptr_add (ip61,
-				vnet_buffer (p1)->map_t.checksum_offset);
-
-	  csum0 = ip_csum_sub_even (*checksum0, ip60->src_address.as_u64[0]);
-	  csum1 = ip_csum_sub_even (*checksum1, ip61->src_address.as_u64[0]);
-	  csum0 = ip_csum_sub_even (csum0, ip60->src_address.as_u64[1]);
-	  csum1 = ip_csum_sub_even (csum1, ip61->src_address.as_u64[1]);
-	  csum0 = ip_csum_sub_even (csum0, ip60->dst_address.as_u64[0]);
-	  csum1 = ip_csum_sub_even (csum0, ip61->dst_address.as_u64[0]);
-	  csum0 = ip_csum_sub_even (csum0, ip60->dst_address.as_u64[1]);
-	  csum1 = ip_csum_sub_even (csum1, ip61->dst_address.as_u64[1]);
-	  csum0 = ip_csum_add_even (csum0, vnet_buffer (p0)->map_t.v6.daddr);
-	  csum1 = ip_csum_add_even (csum1, vnet_buffer (p1)->map_t.v6.daddr);
-	  csum0 = ip_csum_add_even (csum0, vnet_buffer (p0)->map_t.v6.saddr);
-	  csum1 = ip_csum_add_even (csum1, vnet_buffer (p1)->map_t.v6.saddr);
-	  *checksum0 = ip_csum_fold (csum0);
-	  *checksum1 = ip_csum_fold (csum1);
-
-	  if (PREDICT_FALSE (vnet_buffer (p0)->map_t.v6.frag_offset))
-	    {
-	      ip6_frag_hdr_t *hdr = (ip6_frag_hdr_t *) u8_ptr_add (ip60,
-								   vnet_buffer
-								   (p0)->
-								   map_t.
-								   v6.frag_offset);
-	      fragment_id0 = frag_id_6to4 (hdr->identification);
-	      flags0 = clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);
-	    }
-	  else
-	    {
-	      fragment_id0 = 0;
-	      flags0 = 0;
-	    }
 
-	  if (PREDICT_FALSE (vnet_buffer (p1)->map_t.v6.frag_offset))
+	  if (ip6_to_ip4_tcp_udp (p0, ip6_to_ip4_set_cb, p0, 1))
 	    {
-	      ip6_frag_hdr_t *hdr = (ip6_frag_hdr_t *) u8_ptr_add (ip61,
-								   vnet_buffer
-								   (p1)->
-								   map_t.
-								   v6.frag_offset);
-	      fragment_id1 = frag_id_6to4 (hdr->identification);
-	      flags1 = clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);
+	      p0->error = error_node->errors[MAP_ERROR_UNKNOWN];
+	      next0 = IP6_MAPT_TCP_UDP_NEXT_DROP;
 	    }
 	  else
 	    {
-	      fragment_id1 = 0;
-	      flags1 = 0;
+	      if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
+		  vnet_buffer (p0)->ip_frag.header_offset = 0;
+		  vnet_buffer (p0)->ip_frag.next_index =
+		    IP4_FRAG_NEXT_IP4_LOOKUP;
+		  next0 = IP6_MAPT_TCP_UDP_NEXT_IP4_FRAG;
+		}
 	    }
 
-	  ip40->dst_address.as_u32 = vnet_buffer (p0)->map_t.v6.daddr;
-	  ip41->dst_address.as_u32 = vnet_buffer (p1)->map_t.v6.daddr;
-	  ip40->src_address.as_u32 = vnet_buffer (p0)->map_t.v6.saddr;
-	  ip41->src_address.as_u32 = vnet_buffer (p1)->map_t.v6.saddr;
-	  ip40->ip_version_and_header_length =
-	    IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS;
-	  ip41->ip_version_and_header_length =
-	    IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS;
-	  ip40->tos = ip6_translate_tos (ip60);
-	  ip41->tos = ip6_translate_tos (ip61);
-	  ip40->length = u16_net_add (ip60->payload_length,
-				      sizeof (*ip40) + sizeof (*ip60) -
-				      vnet_buffer (p0)->map_t.v6.l4_offset);
-	  ip41->length =
-	    u16_net_add (ip61->payload_length,
-			 sizeof (*ip40) + sizeof (*ip60) -
-			 vnet_buffer (p1)->map_t.v6.l4_offset);
-	  ip40->fragment_id = fragment_id0;
-	  ip41->fragment_id = fragment_id1;
-	  ip40->flags_and_fragment_offset = flags0;
-	  ip41->flags_and_fragment_offset = flags1;
-	  ip40->ttl = ip60->hop_limit;
-	  ip41->ttl = ip61->hop_limit;
-	  ip40->protocol = vnet_buffer (p0)->map_t.v6.l4_protocol;
-	  ip41->protocol = vnet_buffer (p1)->map_t.v6.l4_protocol;
-	  ip40->checksum = ip4_header_checksum (ip40);
-	  ip41->checksum = ip4_header_checksum (ip41);
-
-	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+	  if (ip6_to_ip4_tcp_udp (p1, ip6_to_ip4_set_cb, p1, 1))
 	    {
-	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.header_offset = 0;
-	      vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
-	      next0 = IP6_MAPT_TCP_UDP_NEXT_IP4_FRAG;
+	      p1->error = error_node->errors[MAP_ERROR_UNKNOWN];
+	      next1 = IP6_MAPT_TCP_UDP_NEXT_DROP;
 	    }
-
-	  if (vnet_buffer (p1)->map_t.mtu < p1->current_length)
+	  else
 	    {
-	      vnet_buffer (p1)->ip_frag.mtu = vnet_buffer (p1)->map_t.mtu;
-	      vnet_buffer (p1)->ip_frag.header_offset = 0;
-	      vnet_buffer (p1)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
-	      next1 = IP6_MAPT_TCP_UDP_NEXT_IP4_FRAG;
+	      if (vnet_buffer (p1)->map_t.mtu < p1->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p1)->ip_frag.mtu = vnet_buffer (p1)->map_t.mtu;
+		  vnet_buffer (p1)->ip_frag.header_offset = 0;
+		  vnet_buffer (p1)->ip_frag.next_index =
+		    IP4_FRAG_NEXT_IP4_LOOKUP;
+		  next1 = IP6_MAPT_TCP_UDP_NEXT_IP4_FRAG;
+		}
 	    }
 
 	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next,
@@ -880,12 +450,6 @@ ip6_map_t_tcp_udp (vlib_main_t * vm,
 	{
 	  u32 pi0;
 	  vlib_buffer_t *p0;
-	  ip6_header_t *ip60;
-	  u16 *checksum0;
-	  ip_csum_t csum0;
-	  ip4_header_t *ip40;
-	  u16 fragment_id0;
-	  u16 flags0;
 	  ip6_mapt_tcp_udp_next_t next0;
 
 	  pi0 = to_next[0] = from[0];
@@ -896,65 +460,23 @@ ip6_map_t_tcp_udp (vlib_main_t * vm,
 	  next0 = IP6_MAPT_TCP_UDP_NEXT_IP4_LOOKUP;
 
 	  p0 = vlib_get_buffer (vm, pi0);
-	  ip60 = vlib_buffer_get_current (p0);
-	  ip40 =
-	    (ip4_header_t *) u8_ptr_add (ip60,
-					 vnet_buffer (p0)->map_t.
-					 v6.l4_offset - sizeof (*ip40));
-	  vlib_buffer_advance (p0,
-			       vnet_buffer (p0)->map_t.v6.l4_offset -
-			       sizeof (*ip40));
-	  checksum0 =
-	    (u16 *) u8_ptr_add (ip60,
-				vnet_buffer (p0)->map_t.checksum_offset);
-
-	  //TODO: This can probably be optimized
-	  csum0 = ip_csum_sub_even (*checksum0, ip60->src_address.as_u64[0]);
-	  csum0 = ip_csum_sub_even (csum0, ip60->src_address.as_u64[1]);
-	  csum0 = ip_csum_sub_even (csum0, ip60->dst_address.as_u64[0]);
-	  csum0 = ip_csum_sub_even (csum0, ip60->dst_address.as_u64[1]);
-	  csum0 = ip_csum_add_even (csum0, vnet_buffer (p0)->map_t.v6.daddr);
-	  csum0 = ip_csum_add_even (csum0, vnet_buffer (p0)->map_t.v6.saddr);
-	  *checksum0 = ip_csum_fold (csum0);
-
-	  if (PREDICT_FALSE (vnet_buffer (p0)->map_t.v6.frag_offset))
+
+	  if (ip6_to_ip4_tcp_udp (p0, ip6_to_ip4_set_cb, p0, 1))
 	    {
-	      //Only the first fragment
-	      ip6_frag_hdr_t *hdr = (ip6_frag_hdr_t *) u8_ptr_add (ip60,
-								   vnet_buffer
-								   (p0)->
-								   map_t.
-								   v6.frag_offset);
-	      fragment_id0 = frag_id_6to4 (hdr->identification);
-	      flags0 = clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);
+	      p0->error = error_node->errors[MAP_ERROR_UNKNOWN];
+	      next0 = IP6_MAPT_TCP_UDP_NEXT_DROP;
 	    }
 	  else
 	    {
-	      fragment_id0 = 0;
-	      flags0 = 0;
-	    }
-
-	  ip40->dst_address.as_u32 = vnet_buffer (p0)->map_t.v6.daddr;
-	  ip40->src_address.as_u32 = vnet_buffer (p0)->map_t.v6.saddr;
-	  ip40->ip_version_and_header_length =
-	    IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS;
-	  ip40->tos = ip6_translate_tos (ip60);
-	  ip40->length = u16_net_add (ip60->payload_length,
-				      sizeof (*ip40) + sizeof (*ip60) -
-				      vnet_buffer (p0)->map_t.v6.l4_offset);
-	  ip40->fragment_id = fragment_id0;
-	  ip40->flags_and_fragment_offset = flags0;
-	  ip40->ttl = ip60->hop_limit;
-	  ip40->protocol = vnet_buffer (p0)->map_t.v6.l4_protocol;
-	  ip40->checksum = ip4_header_checksum (ip40);
-
-	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
-	    {
-	      //Send to fragmentation node if necessary
-	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.header_offset = 0;
-	      vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
-	      next0 = IP6_MAPT_TCP_UDP_NEXT_IP4_FRAG;
+	      if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
+		  vnet_buffer (p0)->ip_frag.header_offset = 0;
+		  vnet_buffer (p0)->ip_frag.next_index =
+		    IP4_FRAG_NEXT_IP4_LOOKUP;
+		  next0 = IP6_MAPT_TCP_UDP_NEXT_IP4_FRAG;
+		}
 	    }
 
 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,