ip: functional interface to ip fragmentation

This provides a functional interface to IP fragmentation.
Allowing external features to fragment. Supports
arbitrary encap size, for e.g. MPLS or inner fragmentation
of tunnels.

This also removed dual loop in MAP that was fundamentally broken.

Type: fix
Signed-off-by: Ole Troan <ot@cisco.com>
Change-Id: Ia89ecec8ee3cbe2416edbe87630fdb714898c2a8
Signed-off-by: Ole Troan <ot@cisco.com>

5 files changed, 148 insertions, 214 deletions

diff --git a/src/plugins/map/ip4_map.c b/src/plugins/map/ip4_map.c
index ad94907e499..f2a00907a57 100644
--- a/src/plugins/map/ip4_map.c
+++ b/src/plugins/map/ip4_map.c
@@ -26,8 +26,6 @@ enum ip4_map_next_e
 #ifdef MAP_SKIP_IP6_LOOKUP
   IP4_MAP_NEXT_IP6_REWRITE,
 #endif
-  IP4_MAP_NEXT_IP4_FRAGMENT,
-  IP4_MAP_NEXT_IP6_FRAGMENT,
   IP4_MAP_NEXT_ICMP_ERROR,
   IP4_MAP_NEXT_DROP,
   IP4_MAP_N_NEXT,
@@ -117,17 +115,26 @@ ip4_map_decrement_ttl (ip4_header_t * ip, u8 * error)
 }
 
 static u32
-ip4_map_fragment (vlib_buffer_t * b, u16 mtu, bool df, u8 * error)
+ip4_map_fragment (vlib_main_t * vm, u32 bi, u16 mtu, bool df, u32 ** buffers,
+		  u8 * error)
 {
   map_main_t *mm = &map_main;
+  vlib_buffer_t *b = vlib_get_buffer (vm, bi);
 
   if (mm->frag_inner)
     {
-      // TODO: Fix inner fragmentation after removed inner support from ip-frag.
-      ip_frag_set_vnet_buffer (b, /*sizeof (ip6_header_t), */ mtu,
-			       IP4_FRAG_NEXT_IP6_LOOKUP,
-			       IP_FRAG_FLAG_IP6_HEADER);
-      return (IP4_MAP_NEXT_IP4_FRAGMENT);
+      /* IPv4 fragmented packets inside of IPv6 */
+      ip4_frag_do_fragment (vm, bi, mtu, sizeof (ip6_header_t), buffers);
+
+      /* Fixup */
+      u32 *i;
+      vec_foreach (i, *buffers)
+      {
+	vlib_buffer_t *p = vlib_get_buffer (vm, *i);
+	ip6_header_t *ip6 = vlib_buffer_get_current (p);
+	ip6->payload_length =
+	  clib_host_to_net_u16 (p->current_length - sizeof (ip6_header_t));
+      }
     }
   else
     {
@@ -140,10 +147,11 @@ ip4_map_fragment (vlib_buffer_t * b, u16 mtu, bool df, u8 * error)
 	  *error = MAP_ERROR_DF_SET;
 	  return (IP4_MAP_NEXT_ICMP_ERROR);
 	}
-      ip_frag_set_vnet_buffer (b, mtu, IP6_FRAG_NEXT_IP6_LOOKUP,
-			       IP_FRAG_FLAG_IP6_HEADER);
-      return (IP4_MAP_NEXT_IP6_FRAGMENT);
+
+      /* Create IPv6 fragments here */
+      ip6_frag_do_fragment (vm, bi, mtu, 0, buffers);
     }
+  return (IP4_MAP_NEXT_IP6_LOOKUP);
 }
 
 /*
@@ -165,189 +173,6 @@ ip4_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
   while (n_left_from > 0)
     {
       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
-
-      /* Dual loop */
-      while (n_left_from >= 4 && n_left_to_next >= 2)
-	{
-	  u32 pi0, pi1;
-	  vlib_buffer_t *p0, *p1;
-	  map_domain_t *d0, *d1;
-	  u8 error0 = MAP_ERROR_NONE, error1 = MAP_ERROR_NONE;
-	  ip4_header_t *ip40, *ip41;
-	  u16 port0 = 0, port1 = 0;
-	  ip6_header_t *ip6h0, *ip6h1;
-	  u32 map_domain_index0 = ~0, map_domain_index1 = ~0;
-	  u32 next0 = IP4_MAP_NEXT_IP6_LOOKUP, next1 =
-	    IP4_MAP_NEXT_IP6_LOOKUP;
-
-	  /* Prefetch next iteration. */
-	  {
-	    vlib_buffer_t *p2, *p3;
-
-	    p2 = vlib_get_buffer (vm, from[2]);
-	    p3 = vlib_get_buffer (vm, from[3]);
-
-	    vlib_prefetch_buffer_header (p2, STORE);
-	    vlib_prefetch_buffer_header (p3, STORE);
-	    /* IPv4 + 8 = 28. possibly plus -40 */
-	    CLIB_PREFETCH (p2->data - 40, 68, STORE);
-	    CLIB_PREFETCH (p3->data - 40, 68, STORE);
-	  }
-
-	  pi0 = to_next[0] = from[0];
-	  pi1 = to_next[1] = from[1];
-	  from += 2;
-	  n_left_from -= 2;
-	  to_next += 2;
-	  n_left_to_next -= 2;
-
-	  p0 = vlib_get_buffer (vm, pi0);
-	  p1 = vlib_get_buffer (vm, pi1);
-	  ip40 = vlib_buffer_get_current (p0);
-	  ip41 = vlib_buffer_get_current (p1);
-	  d0 =
-	    ip4_map_get_domain (&ip40->dst_address, &map_domain_index0,
-				&error0);
-	  d1 =
-	    ip4_map_get_domain (&ip41->dst_address, &map_domain_index1,
-				&error1);
-
-	  /*
-	   * Shared IPv4 address
-	   */
-	  port0 = ip4_map_port_and_security_check (d0, p0, &error0);
-	  port1 = ip4_map_port_and_security_check (d1, p1, &error1);
-
-	  /* Decrement IPv4 TTL */
-	  ip4_map_decrement_ttl (ip40, &error0);
-	  ip4_map_decrement_ttl (ip41, &error1);
-	  bool df0 =
-	    ip40->flags_and_fragment_offset &
-	    clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);
-	  bool df1 =
-	    ip41->flags_and_fragment_offset &
-	    clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);
-
-	  /* MAP calc */
-	  u32 da40 = clib_net_to_host_u32 (ip40->dst_address.as_u32);
-	  u32 da41 = clib_net_to_host_u32 (ip41->dst_address.as_u32);
-	  u16 dp40 = clib_net_to_host_u16 (port0);
-	  u16 dp41 = clib_net_to_host_u16 (port1);
-	  u64 dal60 = map_get_pfx (d0, da40, dp40);
-	  u64 dal61 = map_get_pfx (d1, da41, dp41);
-	  u64 dar60 = map_get_sfx (d0, da40, dp40);
-	  u64 dar61 = map_get_sfx (d1, da41, dp41);
-	  if (dal60 == 0 && dar60 == 0 && error0 == MAP_ERROR_NONE)
-	    error0 = MAP_ERROR_NO_BINDING;
-	  if (dal61 == 0 && dar61 == 0 && error1 == MAP_ERROR_NONE)
-	    error1 = MAP_ERROR_NO_BINDING;
-
-	  /* construct ipv6 header */
-	  vlib_buffer_advance (p0, -sizeof (ip6_header_t));
-	  vlib_buffer_advance (p1, -sizeof (ip6_header_t));
-	  ip6h0 = vlib_buffer_get_current (p0);
-	  ip6h1 = vlib_buffer_get_current (p1);
-	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
-	  vnet_buffer (p1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
-
-	  ip6h0->ip_version_traffic_class_and_flow_label =
-	    ip4_map_vtcfl (ip40, p0);
-	  ip6h1->ip_version_traffic_class_and_flow_label =
-	    ip4_map_vtcfl (ip41, p1);
-	  ip6h0->payload_length = ip40->length;
-	  ip6h1->payload_length = ip41->length;
-	  ip6h0->protocol = IP_PROTOCOL_IP_IN_IP;
-	  ip6h1->protocol = IP_PROTOCOL_IP_IN_IP;
-	  ip6h0->hop_limit = 0x40;
-	  ip6h1->hop_limit = 0x40;
-	  ip6h0->src_address = d0->ip6_src;
-	  ip6h1->src_address = d1->ip6_src;
-	  ip6h0->dst_address.as_u64[0] = clib_host_to_net_u64 (dal60);
-	  ip6h0->dst_address.as_u64[1] = clib_host_to_net_u64 (dar60);
-	  ip6h1->dst_address.as_u64[0] = clib_host_to_net_u64 (dal61);
-	  ip6h1->dst_address.as_u64[1] = clib_host_to_net_u64 (dar61);
-
-	  /*
-	   * Determine next node. Can be one of:
-	   * ip6-lookup, ip6-rewrite, ip4-fragment, error-drop
-	   */
-	  if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
-	    {
-	      if (PREDICT_FALSE
-		  (d0->mtu
-		   && (clib_net_to_host_u16 (ip6h0->payload_length) +
-		       sizeof (*ip6h0) > d0->mtu)))
-		{
-		  next0 = ip4_map_fragment (p0, d0->mtu, df0, &error0);
-		}
-	      else
-		{
-		  next0 =
-		    ip4_map_ip6_lookup_bypass (p0,
-					       ip40) ?
-		    IP4_MAP_NEXT_IP6_REWRITE : next0;
-		  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
-						   thread_index,
-						   map_domain_index0, 1,
-						   clib_net_to_host_u16
-						   (ip6h0->payload_length) +
-						   40);
-		}
-	    }
-	  else
-	    {
-	      next0 = IP4_MAP_NEXT_DROP;
-	    }
-
-	  /*
-	   * Determine next node. Can be one of:
-	   * ip6-lookup, ip6-rewrite, ip4-fragment, error-drop
-	   */
-	  if (PREDICT_TRUE (error1 == MAP_ERROR_NONE))
-	    {
-	      if (PREDICT_FALSE
-		  (d1->mtu
-		   && (clib_net_to_host_u16 (ip6h1->payload_length) +
-		       sizeof (*ip6h1) > d1->mtu)))
-		{
-		  next1 = ip4_map_fragment (p1, d1->mtu, df1, &error1);
-		}
-	      else
-		{
-		  next1 =
-		    ip4_map_ip6_lookup_bypass (p1,
-					       ip41) ?
-		    IP4_MAP_NEXT_IP6_REWRITE : next1;
-		  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
-						   thread_index,
-						   map_domain_index1, 1,
-						   clib_net_to_host_u16
-						   (ip6h1->payload_length) +
-						   40);
-		}
-	    }
-	  else
-	    {
-	      next1 = IP4_MAP_NEXT_DROP;
-	    }
-
-	  if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
-	    {
-	      map_add_trace (vm, node, p0, map_domain_index0, port0);
-	    }
-	  if (PREDICT_FALSE (p1->flags & VLIB_BUFFER_IS_TRACED))
-	    {
-	      map_add_trace (vm, node, p1, map_domain_index1, port0);
-	    }
-
-	  p0->error = error_node->errors[error0];
-	  p1->error = error_node->errors[error1];
-
-	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next,
-					   n_left_to_next, pi0, pi1, next0,
-					   next1);
-	}
-
       while (n_left_from > 0 && n_left_to_next > 0)
 	{
 	  u32 pi0;
@@ -359,12 +184,13 @@ ip4_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 	  ip6_header_t *ip6h0;
 	  u32 next0 = IP4_MAP_NEXT_IP6_LOOKUP;
 	  u32 map_domain_index0 = ~0;
+	  u32 *buffer0 = 0;
+	  bool free_original_buffer0 = false;
+	  u32 *frag_from0, frag_left0;
 
 	  pi0 = to_next[0] = from[0];
 	  from += 1;
 	  n_left_from -= 1;
-	  to_next += 1;
-	  n_left_to_next -= 1;
 
 	  p0 = vlib_get_buffer (vm, pi0);
 	  ip40 = vlib_buffer_get_current (p0);
@@ -413,7 +239,7 @@ ip4_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 
 	  /*
 	   * Determine next node. Can be one of:
-	   * ip6-lookup, ip6-rewrite, ip4-fragment, error-drop
+	   * ip6-lookup, ip6-rewrite, error-drop
 	   */
 	  if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
 	    {
@@ -422,7 +248,14 @@ ip4_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 		   && (clib_net_to_host_u16 (ip6h0->payload_length) +
 		       sizeof (*ip6h0) > d0->mtu)))
 		{
-		  next0 = ip4_map_fragment (p0, d0->mtu, df0, &error0);
+		  next0 =
+		    ip4_map_fragment (vm, pi0, d0->mtu, df0, &buffer0,
+				      &error0);
+
+		  if (error0 == MAP_ERROR_NONE)
+		    {
+		      free_original_buffer0 = true;
+		    }
 		}
 	      else
 		{
@@ -450,8 +283,41 @@ ip4_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 
 	  p0->error = error_node->errors[error0];
 	exit:
-	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
-					   n_left_to_next, pi0, next0);
+	  /* Send fragments that were added in the frame */
+	  if (free_original_buffer0)
+	    {
+	      vlib_buffer_free_one (vm, pi0);	/* Free original packet */
+	    }
+	  else
+	    {
+	      vec_add1 (buffer0, pi0);
+	    }
+
+	  frag_from0 = buffer0;
+	  frag_left0 = vec_len (buffer0);
+
+	  while (frag_left0 > 0)
+	    {
+	      while (frag_left0 > 0 && n_left_to_next > 0)
+		{
+		  u32 i0;
+		  i0 = to_next[0] = frag_from0[0];
+		  frag_from0 += 1;
+		  frag_left0 -= 1;
+		  to_next += 1;
+		  n_left_to_next -= 1;
+
+		  vlib_get_buffer (vm, i0)->error =
+		    error_node->errors[error0];
+		  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+						   to_next, n_left_to_next,
+						   i0, next0);
+		}
+	      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+	      vlib_get_next_frame (vm, node, next_index, to_next,
+				   n_left_to_next);
+	    }
+	  vec_reset_length (buffer0);
 	}
       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
     }
@@ -491,8 +357,6 @@ VLIB_REGISTER_NODE(ip4_map_node) = {
 #ifdef MAP_SKIP_IP6_LOOKUP
     [IP4_MAP_NEXT_IP6_REWRITE] = "ip6-load-balance",
 #endif
-    [IP4_MAP_NEXT_IP4_FRAGMENT] = "ip4-frag",
-    [IP4_MAP_NEXT_IP6_FRAGMENT] = "ip6-frag",
     [IP4_MAP_NEXT_ICMP_ERROR] = "ip4-icmp-error",
     [IP4_MAP_NEXT_DROP] = "error-drop",
   },
diff --git a/src/plugins/map/ip4_map_t.c b/src/plugins/map/ip4_map_t.c
index 621fb0615dc..c254efc78b9 100644
--- a/src/plugins/map/ip4_map_t.c
+++ b/src/plugins/map/ip4_map_t.c
@@ -168,7 +168,7 @@ ip4_map_t_icmp (vlib_main_t * vm,
 	  if (vnet_buffer (p0)->map_t.mtu < p0->current_length)
 	    {
 	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
+	      vnet_buffer (p0)->ip_frag.next_index = IP_FRAG_NEXT_IP6_LOOKUP;
 	      next0 = IP4_MAPT_ICMP_NEXT_IP6_FRAG;
 	    }
 	err0:
@@ -287,7 +287,7 @@ ip4_map_t_fragmented (vlib_main_t * vm,
 		{
 		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
 		  vnet_buffer (p0)->ip_frag.next_index =
-		    IP6_FRAG_NEXT_IP6_LOOKUP;
+		    IP_FRAG_NEXT_IP6_LOOKUP;
 		  next0 = IP4_MAPT_FRAGMENTED_NEXT_IP6_FRAG;
 		}
 	    }
@@ -453,7 +453,7 @@ ip4_map_t_tcp_udp (vlib_main_t * vm,
 		  //Send to fragmentation node if necessary
 		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
 		  vnet_buffer (p0)->ip_frag.next_index =
-		    IP6_FRAG_NEXT_IP6_LOOKUP;
+		    IP_FRAG_NEXT_IP6_LOOKUP;
 		  next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
 		}
 	    }
diff --git a/src/plugins/map/ip6_map.c b/src/plugins/map/ip6_map.c
index 96f81efc1cb..47958f92a38 100644
--- a/src/plugins/map/ip6_map.c
+++ b/src/plugins/map/ip6_map.c
@@ -314,7 +314,7 @@ ip6_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 		    {
 		      vnet_buffer (p0)->ip_frag.flags = 0;
 		      vnet_buffer (p0)->ip_frag.next_index =
-			IP4_FRAG_NEXT_IP4_LOOKUP;
+			IP_FRAG_NEXT_IP4_LOOKUP;
 		      vnet_buffer (p0)->ip_frag.mtu = d0->mtu;
 		      next0 = IP6_MAP_NEXT_IP4_FRAGMENT;
 		    }
@@ -346,7 +346,7 @@ ip6_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 		    {
 		      vnet_buffer (p1)->ip_frag.flags = 0;
 		      vnet_buffer (p1)->ip_frag.next_index =
-			IP4_FRAG_NEXT_IP4_LOOKUP;
+			IP_FRAG_NEXT_IP4_LOOKUP;
 		      vnet_buffer (p1)->ip_frag.mtu = d1->mtu;
 		      next1 = IP6_MAP_NEXT_IP4_FRAGMENT;
 		    }
@@ -497,7 +497,7 @@ ip6_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 		    {
 		      vnet_buffer (p0)->ip_frag.flags = 0;
 		      vnet_buffer (p0)->ip_frag.next_index =
-			IP4_FRAG_NEXT_IP4_LOOKUP;
+			IP_FRAG_NEXT_IP4_LOOKUP;
 		      vnet_buffer (p0)->ip_frag.mtu = d0->mtu;
 		      next0 = IP6_MAP_NEXT_IP4_FRAGMENT;
 		    }
@@ -622,7 +622,7 @@ ip6_map_post_ip4_reass (vlib_main_t * vm,
 	       && error0 == MAP_ERROR_NONE))
 	    {
 	      vnet_buffer (p0)->ip_frag.flags = 0;
-	      vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
+	      vnet_buffer (p0)->ip_frag.next_index = IP_FRAG_NEXT_IP4_LOOKUP;
 	      vnet_buffer (p0)->ip_frag.mtu = d0->mtu;
 	      next0 = IP6_MAP_POST_IP4_REASS_NEXT_IP4_FRAGMENT;
 	    }
diff --git a/src/plugins/map/ip6_map_t.c b/src/plugins/map/ip6_map_t.c
index 6e9c0d7640c..ef7b91349e5 100644
--- a/src/plugins/map/ip6_map_t.c
+++ b/src/plugins/map/ip6_map_t.c
@@ -169,7 +169,7 @@ ip6_map_t_icmp (vlib_main_t * vm,
 	    {
 	      // Send to fragmentation node if necessary
 	      vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
-	      vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
+	      vnet_buffer (p0)->ip_frag.next_index = IP_FRAG_NEXT_IP4_LOOKUP;
 	      next0 = IP6_MAPT_ICMP_NEXT_IP4_FRAG;
 	    }
 	err0:
@@ -288,7 +288,7 @@ ip6_map_t_fragmented (vlib_main_t * vm,
 		  // Send to fragmentation node if necessary
 		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
 		  vnet_buffer (p0)->ip_frag.next_index =
-		    IP4_FRAG_NEXT_IP4_LOOKUP;
+		    IP_FRAG_NEXT_IP4_LOOKUP;
 		  next0 = IP6_MAPT_FRAGMENTED_NEXT_IP4_FRAG;
 		}
 	    }
@@ -441,7 +441,7 @@ ip6_map_t_tcp_udp (vlib_main_t * vm,
 		  // Send to fragmentation node if necessary
 		  vnet_buffer (p0)->ip_frag.mtu = vnet_buffer (p0)->map_t.mtu;
 		  vnet_buffer (p0)->ip_frag.next_index =
-		    IP4_FRAG_NEXT_IP4_LOOKUP;
+		    IP_FRAG_NEXT_IP4_LOOKUP;
 		  next0 = IP6_MAPT_TCP_UDP_NEXT_IP4_FRAG;
 		}
 	    }
diff --git a/src/plugins/map/test/test_map.py b/src/plugins/map/test/test_map.py
index a7e5f165576..c1fe05e1150 100644
--- a/src/plugins/map/test/test_map.py
+++ b/src/plugins/map/test/test_map.py
@@ -140,7 +140,7 @@ class TestMAP(VppTestCase):
               IP(src=self.pg0.remote_ip4, dst=self.pg0.remote_ip4) /
               UDP(sport=20000, dport=10000) /
               Raw(b'\xa5' * 100))
-        rx = self.send_and_expect(self.pg0, v4*1, self.pg0)
+        rx = self.send_and_expect(self.pg0, v4 * 4, self.pg0)
         v4_reply = v4[1]
         v4_reply.ttl -= 1
         for p in rx:
@@ -154,7 +154,7 @@ class TestMAP(VppTestCase):
               UDP(sport=20000, dport=10000) /
               Raw(b'\xa5' * 100))
 
-        self.send_and_assert_encapped_one(v4, "3000::1", map_translated_addr)
+        self.send_and_assert_encapped(v4 * 4, "3000::1", map_translated_addr)
 
         #
         # Verify reordered fragments are able to pass as well
@@ -294,6 +294,76 @@ class TestMAP(VppTestCase):
         pre_res_route.remove_vpp_config()
         self.vapi.ppcli("map params pre-resolve del ip6-nh 4001::1")
 
+    def test_map_e_inner_frag(self):
+        """ MAP-E Inner fragmentation """
+
+        #
+        # Add a route to the MAP-BR
+        #
+        map_br_pfx = "2001::"
+        map_br_pfx_len = 32
+        map_route = VppIpRoute(self,
+                               map_br_pfx,
+                               map_br_pfx_len,
+                               [VppRoutePath(self.pg1.remote_ip6,
+                                             self.pg1.sw_if_index)])
+        map_route.add_vpp_config()
+
+        #
+        # Add a domain that maps from pg0 to pg1
+        #
+        map_dst = '2001::/32'
+        map_src = '3000::1/128'
+        client_pfx = '192.168.0.0/16'
+        map_translated_addr = '2001:0:101:7000:0:c0a8:101:7'
+        tag = 'MAP-E tag.'
+        self.vapi.map_add_domain(ip4_prefix=client_pfx,
+                                 ip6_prefix=map_dst,
+                                 ip6_src=map_src,
+                                 ea_bits_len=20,
+                                 psid_offset=4,
+                                 psid_length=4,
+                                 mtu=1000,
+                                 tag=tag)
+
+        # Enable MAP on interface.
+        self.vapi.map_if_enable_disable(is_enable=1,
+                                        sw_if_index=self.pg0.sw_if_index,
+                                        is_translation=0)
+
+        # Enable inner fragmentation
+        self.vapi.map_param_set_fragmentation(inner=1)
+
+        v4 = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+              IP(src=self.pg0.remote_ip4, dst='192.168.1.1') /
+              UDP(sport=20000, dport=10000) /
+              Raw(b'\xa5' * 1300))
+
+        self.pg_send(self.pg0, v4*1)
+        rx = self.pg1.get_capture(2)
+
+        frags = fragment_rfc791(v4[1], 1000)
+        frags[0].id = 0
+        frags[1].id = 0
+        frags[0].ttl -= 1
+        frags[1].ttl -= 1
+        frags[0].chksum = 0
+        frags[1].chksum = 0
+
+        v6_reply1 = (IPv6(src='3000::1', dst=map_translated_addr, hlim=63) /
+                     frags[0])
+        v6_reply2 = (IPv6(src='3000::1', dst=map_translated_addr, hlim=63) /
+                     frags[1])
+        rx[0][1].fl = 0
+        rx[1][1].fl = 0
+        rx[0][1][IP].id = 0
+        rx[1][1][IP].id = 0
+        rx[0][1][IP].chksum = 0
+        rx[1][1][IP].chksum = 0
+
+        self.validate(rx[0][1], v6_reply1)
+        self.validate(rx[1][1], v6_reply2)
+
     def validate(self, rx, expected):
         self.assertEqual(rx, expected.__class__(scapy.compat.raw(expected)))