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, 133 insertions, 687 deletions

diff --git a/src/vnet/map/ip4_map_t.c b/src/vnet/map/ip4_map_t.c
index 5f2bcbf9..b89840cc 100644
--- a/src/vnet/map/ip4_map_t.c
+++ b/src/vnet/map/ip4_map_t.c
@@ -15,6 +15,7 @@
 #include "map.h"
 
 #include "../ip/ip_frag.h"
+#include <vnet/ip/ip4_to_ip6.h>
 
 #define IP4_MAP_T_DUAL_LOOP 1
 
@@ -63,18 +64,6 @@ typedef CLIB_PACKED (struct {
 }) ip4_mapt_pseudo_header_t;
 /* *INDENT-ON* */
 
-#define frag_id_4to6(id) (id)
-
-//TODO: Find the right place in memory for this.
-/* *INDENT-OFF* */
-static u8 icmp_to_icmp6_updater_pointer_table[] =
-  { 0, 1, 4, 4, ~0,
-    ~0, ~0, ~0, 7, 6,
-    ~0, ~0, 8, 8, 8,
-    8, 24, 24, 24, 24
-  };
-/* *INDENT-ON* */
-
 
 static_always_inline int
 ip4_map_fragment_cache (ip4_header_t * ip4, u16 port)
@@ -110,360 +99,41 @@ ip4_map_fragment_get_port (ip4_header_t * ip4)
   return ret;
 }
 
-
-/* Statelessly translates an ICMP packet into ICMPv6.
- *
- * Warning: The checksum will need to be recomputed.
- *
- */
-static_always_inline int
-ip4_icmp_to_icmp6_in_place (icmp46_header_t * icmp, u32 icmp_len,
-			    i32 * receiver_port, ip4_header_t ** inner_ip4)
+typedef struct
 {
-  *inner_ip4 = NULL;
-  switch (icmp->type)
-    {
-    case ICMP4_echo_reply:
-      *receiver_port = ((u16 *) icmp)[2];
-      icmp->type = ICMP6_echo_reply;
-      break;
-    case ICMP4_echo_request:
-      *receiver_port = ((u16 *) icmp)[2];
-      icmp->type = ICMP6_echo_request;
-      break;
-    case ICMP4_destination_unreachable:
-      *inner_ip4 = (ip4_header_t *) (((u8 *) icmp) + 8);
-      *receiver_port = ip4_get_port (*inner_ip4, MAP_SENDER, icmp_len - 8);
-
-      switch (icmp->code)
-	{
-	case ICMP4_destination_unreachable_destination_unreachable_net:	//0
-	case ICMP4_destination_unreachable_destination_unreachable_host:	//1
-	  icmp->type = ICMP6_destination_unreachable;
-	  icmp->code = ICMP6_destination_unreachable_no_route_to_destination;
-	  break;
-	case ICMP4_destination_unreachable_protocol_unreachable:	//2
-	  icmp->type = ICMP6_parameter_problem;
-	  icmp->code = ICMP6_parameter_problem_unrecognized_next_header;
-	  break;
-	case ICMP4_destination_unreachable_port_unreachable:	//3
-	  icmp->type = ICMP6_destination_unreachable;
-	  icmp->code = ICMP6_destination_unreachable_port_unreachable;
-	  break;
-	case ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set:	//4
-	  icmp->type =
-	    ICMP6_packet_too_big;
-	  icmp->code = 0;
-	  {
-	    u32 advertised_mtu = clib_net_to_host_u32 (*((u32 *) (icmp + 1)));
-	    if (advertised_mtu)
-	      advertised_mtu += 20;
-	    else
-	      advertised_mtu = 1000;	//FIXME ! (RFC 1191 - plateau value)
-
-	    //FIXME: = minimum(advertised MTU+20, MTU_of_IPv6_nexthop, (MTU_of_IPv4_nexthop)+20)
-	    *((u32 *) (icmp + 1)) = clib_host_to_net_u32 (advertised_mtu);
-	  }
-	  break;
-
-	case ICMP4_destination_unreachable_source_route_failed:	//5
-	case ICMP4_destination_unreachable_destination_network_unknown:	//6
-	case ICMP4_destination_unreachable_destination_host_unknown:	//7
-	case ICMP4_destination_unreachable_source_host_isolated:	//8
-	case ICMP4_destination_unreachable_network_unreachable_for_type_of_service:	//11
-	case ICMP4_destination_unreachable_host_unreachable_for_type_of_service:	//12
-	  icmp->type =
-	    ICMP6_destination_unreachable;
-	  icmp->code = ICMP6_destination_unreachable_no_route_to_destination;
-	  break;
-	case ICMP4_destination_unreachable_network_administratively_prohibited:	//9
-	case ICMP4_destination_unreachable_host_administratively_prohibited:	//10
-	case ICMP4_destination_unreachable_communication_administratively_prohibited:	//13
-	case ICMP4_destination_unreachable_precedence_cutoff_in_effect:	//15
-	  icmp->type = ICMP6_destination_unreachable;
-	  icmp->code =
-	    ICMP6_destination_unreachable_destination_administratively_prohibited;
-	  break;
-	case ICMP4_destination_unreachable_host_precedence_violation:	//14
-	default:
-	  return -1;
-	}
-      break;
-
-    case ICMP4_time_exceeded:	//11
-      *inner_ip4 = (ip4_header_t *) (((u8 *) icmp) + 8);
-      *receiver_port = ip4_get_port (*inner_ip4, MAP_SENDER, icmp_len - 8);
-      icmp->type = ICMP6_time_exceeded;
-      //icmp->code = icmp->code //unchanged
-      break;
+  map_domain_t *d;
+  u16 recv_port;
+} icmp_to_icmp6_ctx_t;
 
-    case ICMP4_parameter_problem:
-      *inner_ip4 = (ip4_header_t *) (((u8 *) icmp) + 8);
-      *receiver_port = ip4_get_port (*inner_ip4, MAP_SENDER, icmp_len - 8);
+static int
+ip4_to_ip6_set_icmp_cb (ip4_header_t * ip4, ip6_header_t * ip6, void *arg)
+{
+  icmp_to_icmp6_ctx_t *ctx = arg;
 
-      switch (icmp->code)
-	{
-	case ICMP4_parameter_problem_pointer_indicates_error:
-	case ICMP4_parameter_problem_bad_length:
-	  icmp->type = ICMP6_parameter_problem;
-	  icmp->code = ICMP6_parameter_problem_erroneous_header_field;
-	  {
-	    u8 ptr =
-	      icmp_to_icmp6_updater_pointer_table[*((u8 *) (icmp + 1))];
-	    if (ptr == 0xff)
-	      return -1;
-
-	    *((u32 *) (icmp + 1)) = clib_host_to_net_u32 (ptr);
-	  }
-	  break;
-	default:
-	  //All other codes cause dropping the packet
-	  return -1;
-	}
-      break;
+  ip4_map_t_embedded_address (ctx->d, &ip6->src_address, &ip4->src_address);
+  ip6->dst_address.as_u64[0] =
+    map_get_pfx_net (ctx->d, ip4->dst_address.as_u32, ctx->recv_port);
+  ip6->dst_address.as_u64[1] =
+    map_get_sfx_net (ctx->d, ip4->dst_address.as_u32, ctx->recv_port);
 
-    default:
-      //All other types cause dropping the packet
-      return -1;
-      break;
-    }
   return 0;
 }
 
-static_always_inline void
-_ip4_map_t_icmp (map_domain_t * d, vlib_buffer_t * p, u8 * error)
+static int
+ip4_to_ip6_set_inner_icmp_cb (ip4_header_t * ip4, ip6_header_t * ip6,
+			      void *arg)
 {
-  ip4_header_t *ip4, *inner_ip4;
-  ip6_header_t *ip6, *inner_ip6;
-  u32 ip_len;
-  icmp46_header_t *icmp;
-  i32 recv_port;
-  ip_csum_t csum;
-  u16 *inner_L4_checksum = 0;
-  ip6_frag_hdr_t *inner_frag;
-  u32 inner_frag_id;
-  u32 inner_frag_offset;
-  u8 inner_frag_more;
-
-  ip4 = vlib_buffer_get_current (p);
-  ip_len = clib_net_to_host_u16 (ip4->length);
-  ASSERT (ip_len <= p->current_length);
-
-  icmp = (icmp46_header_t *) (ip4 + 1);
-  if (ip4_icmp_to_icmp6_in_place (icmp, ip_len - sizeof (*ip4),
-				  &recv_port, &inner_ip4))
-    {
-      *error = MAP_ERROR_ICMP;
-      return;
-    }
-
-  if (recv_port < 0)
-    {
-      // In case of 1:1 mapping, we don't care about the port
-      if (d->ea_bits_len == 0 && d->rules)
-	{
-	  recv_port = 0;
-	}
-      else
-	{
-	  *error = MAP_ERROR_ICMP;
-	  return;
-	}
-    }
-
-  if (inner_ip4)
-    {
-      //We have 2 headers to translate.
-      //We need to make some room in the middle of the packet
-
-      if (PREDICT_FALSE (ip4_is_fragment (inner_ip4)))
-	{
-	  //Here it starts getting really tricky
-	  //We will add a fragmentation header in the inner packet
-
-	  if (!ip4_is_first_fragment (inner_ip4))
-	    {
-	      //For now we do not handle unless it is the first fragment
-	      //Ideally we should handle the case as we are in slow path already
-	      *error = MAP_ERROR_FRAGMENTED;
-	      return;
-	    }
-
-	  vlib_buffer_advance (p,
-			       -2 * (sizeof (*ip6) - sizeof (*ip4)) -
-			       sizeof (*inner_frag));
-	  ip6 = vlib_buffer_get_current (p);
-	  clib_memcpy (u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4)), ip4,
-		       20 + 8);
-	  ip4 =
-	    (ip4_header_t *) u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4));
-	  icmp = (icmp46_header_t *) (ip4 + 1);
-
-	  inner_ip6 =
-	    (ip6_header_t *) u8_ptr_add (inner_ip4,
-					 sizeof (*ip4) - sizeof (*ip6) -
-					 sizeof (*inner_frag));
-	  inner_frag =
-	    (ip6_frag_hdr_t *) u8_ptr_add (inner_ip6, sizeof (*inner_ip6));
-	  ip6->payload_length =
-	    u16_net_add (ip4->length,
-			 sizeof (*ip6) - 2 * sizeof (*ip4) +
-			 sizeof (*inner_frag));
-	  inner_frag_id = frag_id_4to6 (inner_ip4->fragment_id);
-	  inner_frag_offset = ip4_get_fragment_offset (inner_ip4);
-	  inner_frag_more =
-	    ! !(inner_ip4->flags_and_fragment_offset &
-		clib_net_to_host_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS));
-	}
-      else
-	{
-	  vlib_buffer_advance (p, -2 * (sizeof (*ip6) - sizeof (*ip4)));
-	  ip6 = vlib_buffer_get_current (p);
-	  clib_memcpy (u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4)), ip4,
-		       20 + 8);
-	  ip4 =
-	    (ip4_header_t *) u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4));
-	  icmp = (icmp46_header_t *) u8_ptr_add (ip4, sizeof (*ip4));
-	  inner_ip6 =
-	    (ip6_header_t *) u8_ptr_add (inner_ip4,
-					 sizeof (*ip4) - sizeof (*ip6));
-	  ip6->payload_length =
-	    u16_net_add (ip4->length, sizeof (*ip6) - 2 * sizeof (*ip4));
-	  inner_frag = NULL;
-	}
-
-      if (PREDICT_TRUE (inner_ip4->protocol == IP_PROTOCOL_TCP))
-	{
-	  inner_L4_checksum = &((tcp_header_t *) (inner_ip4 + 1))->checksum;
-	  *inner_L4_checksum =
-	    ip_csum_fold (ip_csum_sub_even
-			  (*inner_L4_checksum,
-			   *((u64 *) (&inner_ip4->src_address))));
-	}
-      else if (PREDICT_TRUE (inner_ip4->protocol == IP_PROTOCOL_UDP))
-	{
-	  inner_L4_checksum = &((udp_header_t *) (inner_ip4 + 1))->checksum;
-	  if (!*inner_L4_checksum)
-	    {
-	      //The inner packet was first translated, and therefore came from IPv6.
-	      //As the packet was an IPv6 packet, the UDP checksum can't be NULL
-	      *error = MAP_ERROR_ICMP;
-	      return;
-	    }
-	  *inner_L4_checksum =
-	    ip_csum_fold (ip_csum_sub_even
-			  (*inner_L4_checksum,
-			   *((u64 *) (&inner_ip4->src_address))));
-	}
-      else if (inner_ip4->protocol == IP_PROTOCOL_ICMP)
-	{
-	  //We have an ICMP inside an ICMP
-	  //It needs to be translated, but not for error ICMP messages
-	  icmp46_header_t *inner_icmp = (icmp46_header_t *) (inner_ip4 + 1);
-	  csum = inner_icmp->checksum;
-	  //Only types ICMP4_echo_request and ICMP4_echo_reply are handled by ip4_icmp_to_icmp6_in_place
-	  csum = ip_csum_sub_even (csum, *((u16 *) inner_icmp));
-	  inner_icmp->type = (inner_icmp->type == ICMP4_echo_request) ?
-	    ICMP6_echo_request : ICMP6_echo_reply;
-	  csum = ip_csum_add_even (csum, *((u16 *) inner_icmp));
-	  csum =
-	    ip_csum_add_even (csum, clib_host_to_net_u16 (IP_PROTOCOL_ICMP6));
-	  csum =
-	    ip_csum_add_even (csum, inner_ip4->length - sizeof (*inner_ip4));
-	  inner_icmp->checksum = ip_csum_fold (csum);
-	  inner_L4_checksum = &inner_icmp->checksum;
-	  inner_ip4->protocol = IP_PROTOCOL_ICMP6;
-	}
-      else
-	{
-	  /* To shut up Coverity */
-	  os_panic ();
-	}
-
-      //FIXME: Security check with the port found in the inner packet
-
-      csum = *inner_L4_checksum;	//Initial checksum of the inner L4 header
-      //FIXME: Shouldn't we remove ip addresses from there ?
-
-      inner_ip6->ip_version_traffic_class_and_flow_label =
-	clib_host_to_net_u32 ((6 << 28) + (inner_ip4->tos << 20));
-      inner_ip6->payload_length =
-	u16_net_add (inner_ip4->length, -sizeof (*inner_ip4));
-      inner_ip6->hop_limit = inner_ip4->ttl;
-      inner_ip6->protocol = inner_ip4->protocol;
+  icmp_to_icmp6_ctx_t *ctx = arg;
 
-      //Note that the source address is within the domain
-      //while the destination address is the one outside the domain
-      ip4_map_t_embedded_address (d, &inner_ip6->dst_address,
-				  &inner_ip4->dst_address);
-      inner_ip6->src_address.as_u64[0] =
-	map_get_pfx_net (d, inner_ip4->src_address.as_u32, recv_port);
-      inner_ip6->src_address.as_u64[1] =
-	map_get_sfx_net (d, inner_ip4->src_address.as_u32, recv_port);
+  //Note that the source address is within the domain
+  //while the destination address is the one outside the domain
+  ip4_map_t_embedded_address (ctx->d, &ip6->dst_address, &ip4->dst_address);
+  ip6->src_address.as_u64[0] =
+    map_get_pfx_net (ctx->d, ip4->src_address.as_u32, ctx->recv_port);
+  ip6->src_address.as_u64[1] =
+    map_get_sfx_net (ctx->d, ip4->src_address.as_u32, ctx->recv_port);
 
-      if (PREDICT_FALSE (inner_frag != NULL))
-	{
-	  inner_frag->next_hdr = inner_ip6->protocol;
-	  inner_frag->identification = inner_frag_id;
-	  inner_frag->rsv = 0;
-	  inner_frag->fragment_offset_and_more =
-	    ip6_frag_hdr_offset_and_more (inner_frag_offset, inner_frag_more);
-	  inner_ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
-	  inner_ip6->payload_length =
-	    clib_host_to_net_u16 (clib_net_to_host_u16
-				  (inner_ip6->payload_length) +
-				  sizeof (*inner_frag));
-	}
-
-      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]);
-      *inner_L4_checksum = ip_csum_fold (csum);
-
-    }
-  else
-    {
-      vlib_buffer_advance (p, sizeof (*ip4) - sizeof (*ip6));
-      ip6 = vlib_buffer_get_current (p);
-      ip6->payload_length =
-	clib_host_to_net_u16 (clib_net_to_host_u16 (ip4->length) -
-			      sizeof (*ip4));
-    }
-
-  //Translate outer IPv6
-  ip6->ip_version_traffic_class_and_flow_label =
-    clib_host_to_net_u32 ((6 << 28) + (ip4->tos << 20));
-
-  ip6->hop_limit = ip4->ttl;
-  ip6->protocol = IP_PROTOCOL_ICMP6;
-
-  ip4_map_t_embedded_address (d, &ip6->src_address, &ip4->src_address);
-  ip6->dst_address.as_u64[0] =
-    map_get_pfx_net (d, ip4->dst_address.as_u32, recv_port);
-  ip6->dst_address.as_u64[1] =
-    map_get_sfx_net (d, ip4->dst_address.as_u32, recv_port);
-
-  //Truncate when the packet exceeds the minimal IPv6 MTU
-  if (p->current_length > 1280)
-    {
-      ip6->payload_length = clib_host_to_net_u16 (1280 - sizeof (*ip6));
-      p->current_length = 1280;	//Looks too simple to be correct...
-    }
-
-  //TODO: We could do an easy diff-checksum for echo requests/replies
-  //Recompute ICMP checksum
-  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 uword
@@ -491,6 +161,8 @@ ip4_map_t_icmp (vlib_main_t * vm,
 	  u8 error0;
 	  map_domain_t *d0;
 	  u16 len0;
+	  icmp_to_icmp6_ctx_t ctx0;
+	  ip4_header_t *ip40;
 
 	  next0 = IP4_MAPT_ICMP_NEXT_IP6_LOOKUP;
 	  pi0 = to_next[0] = from[0];
@@ -508,7 +180,27 @@ ip4_map_t_icmp (vlib_main_t * vm,
 	  d0 =
 	    pool_elt_at_index (map_main.domains,
 			       vnet_buffer (p0)->map_t.map_domain_index);
-	  _ip4_map_t_icmp (d0, p0, &error0);
+
+	  ip40 = vlib_buffer_get_current (p0);
+	  ctx0.recv_port = ip4_get_port (ip40, 1);
+	  ctx0.d = d0;
+	  if (ctx0.recv_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 (icmp_to_icmp6
+	      (p0, ip4_to_ip6_set_icmp_cb, &ctx0,
+	       ip4_to_ip6_set_inner_icmp_cb, &ctx0))
+	    {
+	      error0 = MAP_ERROR_ICMP;
+	      goto err0;
+	    }
 
 	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
 	    {
@@ -517,12 +209,14 @@ ip4_map_t_icmp (vlib_main_t * vm,
 	      vnet_buffer (p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
 	      next0 = IP4_MAPT_ICMP_NEXT_IP6_FRAG;
 	    }
+	err0:
 	  if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
 	    {
 	      vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
 					       thread_index,
-					       vnet_buffer (p0)->map_t.
-					       map_domain_index, 1, len0);
+					       vnet_buffer (p0)->
+					       map_t.map_domain_index, 1,
+					       len0);
 	    }
 	  else
 	    {
@@ -538,6 +232,19 @@ ip4_map_t_icmp (vlib_main_t * vm,
   return frame->n_vectors;
 }
 
+static int
+ip4_to_ip6_set_cb (ip4_header_t * ip4, ip6_header_t * ip6, void *ctx)
+{
+  ip4_mapt_pseudo_header_t *pheader = ctx;
+
+  ip6->dst_address.as_u64[0] = pheader->daddr.as_u64[0];
+  ip6->dst_address.as_u64[1] = pheader->daddr.as_u64[1];
+  ip6->src_address.as_u64[0] = pheader->saddr.as_u64[0];
+  ip6->src_address.as_u64[1] = pheader->saddr.as_u64[1];
+
+  return 0;
+}
+
 static uword
 ip4_map_t_fragmented (vlib_main_t * vm,
 		      vlib_node_runtime_t * node, vlib_frame_t * frame)
@@ -546,6 +253,8 @@ ip4_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, ip4_map_t_fragmented_node.index);
 
   while (n_left_from > 0)
     {
@@ -555,9 +264,6 @@ ip4_map_t_fragmented (vlib_main_t * vm,
 	{
 	  u32 pi0;
 	  vlib_buffer_t *p0;
-	  ip4_header_t *ip40;
-	  ip6_header_t *ip60;
-	  ip6_frag_hdr_t *frag0;
 	  ip4_mapt_pseudo_header_t *pheader0;
 	  ip4_mapt_fragmented_next_t next0;
 
@@ -574,50 +280,21 @@ ip4_map_t_fragmented (vlib_main_t * vm,
 	  pheader0 = vlib_buffer_get_current (p0);
 	  vlib_buffer_advance (p0, sizeof (*pheader0));
 
-	  //Accessing ip4 header
-	  ip40 = vlib_buffer_get_current (p0);
-	  frag0 =
-	    (ip6_frag_hdr_t *) u8_ptr_add (ip40,
-					   sizeof (*ip40) - sizeof (*frag0));
-	  ip60 =
-	    (ip6_header_t *) u8_ptr_add (ip40,
-					 sizeof (*ip40) - sizeof (*frag0) -
-					 sizeof (*ip60));
-	  vlib_buffer_advance (p0,
-			       sizeof (*ip40) - sizeof (*ip60) -
-			       sizeof (*frag0));
-
-	  //We know that the protocol was one of ICMP, TCP or UDP
-	  //because the first fragment was found and cached
-	  frag0->next_hdr =
-	    (ip40->protocol ==
-	     IP_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP6 : ip40->protocol;
-	  frag0->identification = frag_id_4to6 (ip40->fragment_id);
-	  frag0->rsv = 0;
-	  frag0->fragment_offset_and_more =
-	    ip6_frag_hdr_offset_and_more (ip4_get_fragment_offset (ip40),
-					  clib_net_to_host_u16
-					  (ip40->flags_and_fragment_offset) &
-					  IP4_HEADER_FLAG_MORE_FRAGMENTS);
-
-	  ip60->ip_version_traffic_class_and_flow_label =
-	    clib_host_to_net_u32 ((6 << 28) + (ip40->tos << 20));
-	  ip60->payload_length =
-	    clib_host_to_net_u16 (clib_net_to_host_u16 (ip40->length) -
-				  sizeof (*ip40) + sizeof (*frag0));
-	  ip60->hop_limit = ip40->ttl;
-	  ip60->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
-	  ip60->dst_address.as_u64[0] = pheader0->daddr.as_u64[0];
-	  ip60->dst_address.as_u64[1] = pheader0->daddr.as_u64[1];
-	  ip60->src_address.as_u64[0] = pheader0->saddr.as_u64[0];
-	  ip60->src_address.as_u64[1] = pheader0->saddr.as_u64[1];
-
-	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+	  if (ip4_to_ip6_fragmented (p0, ip4_to_ip6_set_cb, pheader0))
 	    {
-	      vnet_buffer (p0)->ip_frag.header_offset = 0;
-	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
-	      next0 = IP4_MAPT_FRAGMENTED_NEXT_IP6_FRAG;
+	      p0->error = error_node->errors[MAP_ERROR_FRAGMENT_DROPPED];
+	      next0 = IP4_MAPT_FRAGMENTED_NEXT_DROP;
+	    }
+	  else
+	    {
+	      if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+		{
+		  vnet_buffer (p0)->ip_frag.header_offset = 0;
+		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
+		  vnet_buffer (p0)->ip_frag.next_index =
+		    IP6_FRAG_NEXT_IP6_LOOKUP;
+		  next0 = IP4_MAPT_FRAGMENTED_NEXT_IP6_FRAG;
+		}
 	    }
 
 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
@@ -637,6 +314,9 @@ ip4_map_t_tcp_udp (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, ip4_map_t_tcp_udp_node.index);
+
 
   while (n_left_from > 0)
     {
@@ -647,12 +327,6 @@ ip4_map_t_tcp_udp (vlib_main_t * vm,
 	{
 	  u32 pi0, pi1;
 	  vlib_buffer_t *p0, *p1;
-	  ip4_header_t *ip40, *ip41;
-	  ip6_header_t *ip60, *ip61;
-	  ip_csum_t csum0, csum1;
-	  u16 *checksum0, *checksum1;
-	  ip6_frag_hdr_t *frag0, *frag1;
-	  u32 frag_id0, frag_id1;
 	  ip4_mapt_pseudo_header_t *pheader0, *pheader1;
 	  ip4_mapt_tcp_udp_next_t next0, next1;
 
@@ -674,183 +348,40 @@ ip4_map_t_tcp_udp (vlib_main_t * vm,
 	  vlib_buffer_advance (p0, sizeof (*pheader0));
 	  vlib_buffer_advance (p1, sizeof (*pheader1));
 
-	  //Accessing ip4 header
-	  ip40 = vlib_buffer_get_current (p0);
-	  ip41 = vlib_buffer_get_current (p1);
-	  checksum0 =
-	    (u16 *) u8_ptr_add (ip40,
-				vnet_buffer (p0)->map_t.checksum_offset);
-	  checksum1 =
-	    (u16 *) u8_ptr_add (ip41,
-				vnet_buffer (p1)->map_t.checksum_offset);
-
-	  //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
-	      (!*checksum0 && ip40->protocol == IP_PROTOCOL_UDP))
+	  if (ip4_to_ip6_tcp_udp (p0, ip4_to_ip6_set_cb, pheader0))
 	    {
-	      u16 udp_len =
-		clib_host_to_net_u16 (ip40->length) - sizeof (*ip40);
-	      udp_header_t *udp =
-		(udp_header_t *) u8_ptr_add (ip40, sizeof (*ip40));
-	      ip_csum_t csum;
-	      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 *) (&ip40->src_address)));
-	      *checksum0 = ~ip_csum_fold (csum);
-	    }
-	  if (PREDICT_FALSE
-	      (!*checksum1 && ip41->protocol == IP_PROTOCOL_UDP))
-	    {
-	      u16 udp_len =
-		clib_host_to_net_u16 (ip41->length) - sizeof (*ip40);
-	      udp_header_t *udp =
-		(udp_header_t *) u8_ptr_add (ip41, sizeof (*ip40));
-	      ip_csum_t csum;
-	      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 *) (&ip41->src_address)));
-	      *checksum1 = ~ip_csum_fold (csum);
-	    }
-
-	  csum0 = ip_csum_sub_even (*checksum0, ip40->src_address.as_u32);
-	  csum1 = ip_csum_sub_even (*checksum1, ip41->src_address.as_u32);
-	  csum0 = ip_csum_sub_even (csum0, ip40->dst_address.as_u32);
-	  csum1 = ip_csum_sub_even (csum1, ip41->dst_address.as_u32);
-
-	  // Deal with fragmented packets
-	  if (PREDICT_FALSE (ip40->flags_and_fragment_offset &
-			     clib_host_to_net_u16
-			     (IP4_HEADER_FLAG_MORE_FRAGMENTS)))
-	    {
-	      ip60 =
-		(ip6_header_t *) u8_ptr_add (ip40,
-					     sizeof (*ip40) - sizeof (*ip60) -
-					     sizeof (*frag0));
-	      frag0 =
-		(ip6_frag_hdr_t *) u8_ptr_add (ip40,
-					       sizeof (*ip40) -
-					       sizeof (*frag0));
-	      frag_id0 = frag_id_4to6 (ip40->fragment_id);
-	      vlib_buffer_advance (p0,
-				   sizeof (*ip40) - sizeof (*ip60) -
-				   sizeof (*frag0));
+	      p0->error = error_node->errors[MAP_ERROR_UNKNOWN];
+	      next0 = IP4_MAPT_TCP_UDP_NEXT_DROP;
 	    }
 	  else
 	    {
-	      ip60 =
-		(ip6_header_t *) (((u8 *) ip40) + sizeof (*ip40) -
-				  sizeof (*ip60));
-	      vlib_buffer_advance (p0, sizeof (*ip40) - sizeof (*ip60));
-	      frag0 = NULL;
+	      if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p0)->ip_frag.header_offset = 0;
+		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
+		  vnet_buffer (p0)->ip_frag.next_index =
+		    IP6_FRAG_NEXT_IP6_LOOKUP;
+		  next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
+		}
 	    }
 
-	  if (PREDICT_FALSE (ip41->flags_and_fragment_offset &
-			     clib_host_to_net_u16
-			     (IP4_HEADER_FLAG_MORE_FRAGMENTS)))
+	  if (ip4_to_ip6_tcp_udp (p1, ip4_to_ip6_set_cb, pheader1))
 	    {
-	      ip61 =
-		(ip6_header_t *) u8_ptr_add (ip41,
-					     sizeof (*ip40) - sizeof (*ip60) -
-					     sizeof (*frag0));
-	      frag1 =
-		(ip6_frag_hdr_t *) u8_ptr_add (ip41,
-					       sizeof (*ip40) -
-					       sizeof (*frag0));
-	      frag_id1 = frag_id_4to6 (ip41->fragment_id);
-	      vlib_buffer_advance (p1,
-				   sizeof (*ip40) - sizeof (*ip60) -
-				   sizeof (*frag0));
+	      p1->error = error_node->errors[MAP_ERROR_UNKNOWN];
+	      next1 = IP4_MAPT_TCP_UDP_NEXT_DROP;
 	    }
 	  else
 	    {
-	      ip61 =
-		(ip6_header_t *) (((u8 *) ip41) + sizeof (*ip40) -
-				  sizeof (*ip60));
-	      vlib_buffer_advance (p1, sizeof (*ip40) - sizeof (*ip60));
-	      frag1 = NULL;
-	    }
-
-	  ip60->ip_version_traffic_class_and_flow_label =
-	    clib_host_to_net_u32 ((6 << 28) + (ip40->tos << 20));
-	  ip61->ip_version_traffic_class_and_flow_label =
-	    clib_host_to_net_u32 ((6 << 28) + (ip41->tos << 20));
-	  ip60->payload_length = u16_net_add (ip40->length, -sizeof (*ip40));
-	  ip61->payload_length = u16_net_add (ip41->length, -sizeof (*ip40));
-	  ip60->hop_limit = ip40->ttl;
-	  ip61->hop_limit = ip41->ttl;
-	  ip60->protocol = ip40->protocol;
-	  ip61->protocol = ip41->protocol;
-
-	  if (PREDICT_FALSE (frag0 != NULL))
-	    {
-	      frag0->next_hdr = ip60->protocol;
-	      frag0->identification = frag_id0;
-	      frag0->rsv = 0;
-	      frag0->fragment_offset_and_more =
-		ip6_frag_hdr_offset_and_more (0, 1);
-	      ip60->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
-	      ip60->payload_length =
-		u16_net_add (ip60->payload_length, sizeof (*frag0));
-	    }
-
-	  if (PREDICT_FALSE (frag1 != NULL))
-	    {
-	      frag1->next_hdr = ip61->protocol;
-	      frag1->identification = frag_id1;
-	      frag1->rsv = 0;
-	      frag1->fragment_offset_and_more =
-		ip6_frag_hdr_offset_and_more (0, 1);
-	      ip61->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
-	      ip61->payload_length =
-		u16_net_add (ip61->payload_length, sizeof (*frag0));
-	    }
-
-	  //Finally copying the address
-	  ip60->dst_address.as_u64[0] = pheader0->daddr.as_u64[0];
-	  ip61->dst_address.as_u64[0] = pheader1->daddr.as_u64[0];
-	  ip60->dst_address.as_u64[1] = pheader0->daddr.as_u64[1];
-	  ip61->dst_address.as_u64[1] = pheader1->daddr.as_u64[1];
-	  ip60->src_address.as_u64[0] = pheader0->saddr.as_u64[0];
-	  ip61->src_address.as_u64[0] = pheader1->saddr.as_u64[0];
-	  ip60->src_address.as_u64[1] = pheader0->saddr.as_u64[1];
-	  ip61->src_address.as_u64[1] = pheader1->saddr.as_u64[1];
-
-	  csum0 = ip_csum_add_even (csum0, ip60->src_address.as_u64[0]);
-	  csum1 = ip_csum_add_even (csum1, ip61->src_address.as_u64[0]);
-	  csum0 = ip_csum_add_even (csum0, ip60->src_address.as_u64[1]);
-	  csum1 = ip_csum_add_even (csum1, ip61->src_address.as_u64[1]);
-	  csum0 = ip_csum_add_even (csum0, ip60->dst_address.as_u64[0]);
-	  csum1 = ip_csum_add_even (csum1, ip61->dst_address.as_u64[0]);
-	  csum0 = ip_csum_add_even (csum0, ip60->dst_address.as_u64[1]);
-	  csum1 = ip_csum_add_even (csum1, ip61->dst_address.as_u64[1]);
-	  *checksum0 = ip_csum_fold (csum0);
-	  *checksum1 = ip_csum_fold (csum1);
-
-	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
-	    {
-	      vnet_buffer (p0)->ip_frag.header_offset = 0;
-	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
-	      next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
-	    }
-
-	  if (vnet_buffer (p1)->map_t.mtu < p1->current_length)
-	    {
-	      vnet_buffer (p1)->ip_frag.header_offset = 0;
-	      vnet_buffer (p1)->ip_frag.mtu = vnet_buffer (p1)->map_t.mtu;
-	      vnet_buffer (p1)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
-	      next1 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
+	      if (vnet_buffer (p1)->map_t.mtu < p1->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p1)->ip_frag.header_offset = 0;
+		  vnet_buffer (p1)->ip_frag.mtu = vnet_buffer (p1)->map_t.mtu;
+		  vnet_buffer (p1)->ip_frag.next_index =
+		    IP6_FRAG_NEXT_IP6_LOOKUP;
+		  next1 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
+		}
 	    }
 
 	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
@@ -863,12 +394,6 @@ ip4_map_t_tcp_udp (vlib_main_t * vm,
 	{
 	  u32 pi0;
 	  vlib_buffer_t *p0;
-	  ip4_header_t *ip40;
-	  ip6_header_t *ip60;
-	  ip_csum_t csum0;
-	  u16 *checksum0;
-	  ip6_frag_hdr_t *frag0;
-	  u32 frag_id0;
 	  ip4_mapt_pseudo_header_t *pheader0;
 	  ip4_mapt_tcp_udp_next_t next0;
 
@@ -885,102 +410,23 @@ ip4_map_t_tcp_udp (vlib_main_t * vm,
 	  pheader0 = vlib_buffer_get_current (p0);
 	  vlib_buffer_advance (p0, sizeof (*pheader0));
 
-	  //Accessing ip4 header
-	  ip40 = vlib_buffer_get_current (p0);
-	  checksum0 =
-	    (u16 *) u8_ptr_add (ip40,
-				vnet_buffer (p0)->map_t.checksum_offset);
-
-	  //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
-	      (!*checksum0 && ip40->protocol == IP_PROTOCOL_UDP))
-	    {
-	      u16 udp_len =
-		clib_host_to_net_u16 (ip40->length) - sizeof (*ip40);
-	      udp_header_t *udp =
-		(udp_header_t *) u8_ptr_add (ip40, sizeof (*ip40));
-	      ip_csum_t csum;
-	      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 *) (&ip40->src_address)));
-	      *checksum0 = ~ip_csum_fold (csum);
-	    }
-
-	  csum0 = ip_csum_sub_even (*checksum0, ip40->src_address.as_u32);
-	  csum0 = ip_csum_sub_even (csum0, ip40->dst_address.as_u32);
-
-	  // Deal with fragmented packets
-	  if (PREDICT_FALSE (ip40->flags_and_fragment_offset &
-			     clib_host_to_net_u16
-			     (IP4_HEADER_FLAG_MORE_FRAGMENTS)))
+	  if (ip4_to_ip6_tcp_udp (p0, ip4_to_ip6_set_cb, pheader0))
 	    {
-	      ip60 =
-		(ip6_header_t *) u8_ptr_add (ip40,
-					     sizeof (*ip40) - sizeof (*ip60) -
-					     sizeof (*frag0));
-	      frag0 =
-		(ip6_frag_hdr_t *) u8_ptr_add (ip40,
-					       sizeof (*ip40) -
-					       sizeof (*frag0));
-	      frag_id0 = frag_id_4to6 (ip40->fragment_id);
-	      vlib_buffer_advance (p0,
-				   sizeof (*ip40) - sizeof (*ip60) -
-				   sizeof (*frag0));
+	      p0->error = error_node->errors[MAP_ERROR_UNKNOWN];
+	      next0 = IP4_MAPT_TCP_UDP_NEXT_DROP;
 	    }
 	  else
 	    {
-	      ip60 =
-		(ip6_header_t *) (((u8 *) ip40) + sizeof (*ip40) -
-				  sizeof (*ip60));
-	      vlib_buffer_advance (p0, sizeof (*ip40) - sizeof (*ip60));
-	      frag0 = NULL;
+	      if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
+		{
+		  //Send to fragmentation node if necessary
+		  vnet_buffer (p0)->ip_frag.header_offset = 0;
+		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
+		  vnet_buffer (p0)->ip_frag.next_index =
+		    IP6_FRAG_NEXT_IP6_LOOKUP;
+		  next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
+		}
 	    }
-
-	  ip60->ip_version_traffic_class_and_flow_label =
-	    clib_host_to_net_u32 ((6 << 28) + (ip40->tos << 20));
-	  ip60->payload_length = u16_net_add (ip40->length, -sizeof (*ip40));
-	  ip60->hop_limit = ip40->ttl;
-	  ip60->protocol = ip40->protocol;
-
-	  if (PREDICT_FALSE (frag0 != NULL))
-	    {
-	      frag0->next_hdr = ip60->protocol;
-	      frag0->identification = frag_id0;
-	      frag0->rsv = 0;
-	      frag0->fragment_offset_and_more =
-		ip6_frag_hdr_offset_and_more (0, 1);
-	      ip60->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
-	      ip60->payload_length =
-		u16_net_add (ip60->payload_length, sizeof (*frag0));
-	    }
-
-	  //Finally copying the address
-	  ip60->dst_address.as_u64[0] = pheader0->daddr.as_u64[0];
-	  ip60->dst_address.as_u64[1] = pheader0->daddr.as_u64[1];
-	  ip60->src_address.as_u64[0] = pheader0->saddr.as_u64[0];
-	  ip60->src_address.as_u64[1] = pheader0->saddr.as_u64[1];
-
-	  csum0 = ip_csum_add_even (csum0, ip60->src_address.as_u64[0]);
-	  csum0 = ip_csum_add_even (csum0, ip60->src_address.as_u64[1]);
-	  csum0 = ip_csum_add_even (csum0, ip60->dst_address.as_u64[0]);
-	  csum0 = ip_csum_add_even (csum0, ip60->dst_address.as_u64[1]);
-	  *checksum0 = ip_csum_fold (csum0);
-
-	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
-	    {
-	      //Send to fragmentation node if necessary
-	      vnet_buffer (p0)->ip_frag.header_offset = 0;
-	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
-	      next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
-	    }
-
 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 					   to_next, n_left_to_next, pi0,
 					   next0);
@@ -1159,10 +605,10 @@ ip4_map_t (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 	    {
 	      vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
 					       thread_index,
-					       vnet_buffer (p0)->map_t.
-					       map_domain_index, 1,
-					       clib_net_to_host_u16 (ip40->
-								     length));
+					       vnet_buffer (p0)->
+					       map_t.map_domain_index, 1,
+					       clib_net_to_host_u16
+					       (ip40->length));
 	    }
 
 	  if (PREDICT_TRUE
@@ -1170,10 +616,10 @@ ip4_map_t (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 	    {
 	      vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
 					       thread_index,
-					       vnet_buffer (p1)->map_t.
-					       map_domain_index, 1,
-					       clib_net_to_host_u16 (ip41->
-								     length));
+					       vnet_buffer (p1)->
+					       map_t.map_domain_index, 1,
+					       clib_net_to_host_u16
+					       (ip41->length));
 	    }
 
 	  next0 = (error0 != MAP_ERROR_NONE) ? IP4_MAPT_NEXT_DROP : next0;
@@ -1253,10 +699,10 @@ ip4_map_t (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 	    {
 	      vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
 					       thread_index,
-					       vnet_buffer (p0)->map_t.
-					       map_domain_index, 1,
-					       clib_net_to_host_u16 (ip40->
-								     length));
+					       vnet_buffer (p0)->
+					       map_t.map_domain_index, 1,
+					       clib_net_to_host_u16
+					       (ip40->length));
 	    }
 
 	  next0 = (error0 != MAP_ERROR_NONE) ? IP4_MAPT_NEXT_DROP : next0;