Add GTP-U plugin. VPP-694

Basic GTP-U feature

Change-Id: I31226f890a92c5303ac06e112ed7820cae52d9bd
Signed-off-by: Hongjun Ni <hongjun.ni@intel.com>

1 files changed, 1305 insertions, 0 deletions

diff --git a/src/plugins/gtpu/gtpu_decap.c b/src/plugins/gtpu/gtpu_decap.c
new file mode 100644
index 00000000000..b0be32ec12a
--- /dev/null
+++ b/src/plugins/gtpu/gtpu_decap.c
@@ -0,0 +1,1305 @@
+/*
+ * decap.c: gtpu tunnel decap packet processing
+ *
+ * Copyright (c) 2013 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/pg/pg.h>
+#include <gtpu/gtpu.h>
+
+vlib_node_registration_t gtpu4_input_node;
+vlib_node_registration_t gtpu6_input_node;
+
+typedef struct {
+  u32 next_index;
+  u32 tunnel_index;
+  u32 error;
+  u32 teid;
+} gtpu_rx_trace_t;
+
+static u8 * format_gtpu_rx_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 *);
+  gtpu_rx_trace_t * t = va_arg (*args, gtpu_rx_trace_t *);
+
+  if (t->tunnel_index != ~0)
+    {
+      s = format (s, "GTPU decap from gtpu_tunnel%d teid %d next %d error %d",
+                  t->tunnel_index, t->teid, t->next_index, t->error);
+    }
+  else
+    {
+      s = format (s, "GTPU decap error - tunnel for teid %d does not exist",
+		  t->teid);
+    }
+  return s;
+}
+
+always_inline u32
+validate_gtpu_fib (vlib_buffer_t *b, gtpu_tunnel_t *t, u32 is_ip4)
+{
+  u32 fib_index, sw_if_index;
+
+  sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
+
+  if (is_ip4)
+    fib_index = (vnet_buffer (b)->sw_if_index[VLIB_TX] == (u32) ~ 0) ?
+	vec_elt (ip4_main.fib_index_by_sw_if_index, sw_if_index) :
+	vnet_buffer (b)->sw_if_index[VLIB_TX];
+  else
+    fib_index = (vnet_buffer (b)->sw_if_index[VLIB_TX] == (u32) ~ 0) ?
+	vec_elt (ip6_main.fib_index_by_sw_if_index, sw_if_index) :
+	vnet_buffer (b)->sw_if_index[VLIB_TX];
+
+  return (fib_index == t->encap_fib_index);
+}
+
+always_inline uword
+gtpu_input (vlib_main_t * vm,
+             vlib_node_runtime_t * node,
+             vlib_frame_t * from_frame,
+             u32 is_ip4)
+{
+  u32 n_left_from, next_index, * from, * to_next;
+  gtpu_main_t * gtm = &gtpu_main;
+  vnet_main_t * vnm = gtm->vnet_main;
+  vnet_interface_main_t * im = &vnm->interface_main;
+  u32 last_tunnel_index = ~0;
+  gtpu4_tunnel_key_t last_key4;
+  gtpu6_tunnel_key_t last_key6;
+  u32 pkts_decapsulated = 0;
+  u32 thread_index = vlib_get_thread_index();
+  u32 stats_sw_if_index, stats_n_packets, stats_n_bytes;
+
+  if (is_ip4)
+    last_key4.as_u64 = ~0;
+  else
+    memset (&last_key6, 0xff, sizeof (last_key6));
+
+  from = vlib_frame_vector_args (from_frame);
+  n_left_from = from_frame->n_vectors;
+
+  next_index = node->cached_next_index;
+  stats_sw_if_index = node->runtime_data[0];
+  stats_n_packets = stats_n_bytes = 0;
+
+  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 >= 4 && n_left_to_next >= 2)
+	{
+          u32 bi0, bi1;
+	  vlib_buffer_t * b0, * b1;
+	  u32 next0, next1;
+          ip4_header_t * ip4_0, * ip4_1;
+          ip6_header_t * ip6_0, * ip6_1;
+          gtpu_header_t * gtpu0, * gtpu1;
+          u32 gtpu_hdr_len0 = 0, gtpu_hdr_len1 =0 ;
+	  uword * p0, * p1;
+          u32 tunnel_index0, tunnel_index1;
+          gtpu_tunnel_t * t0, * t1, * mt0 = NULL, * mt1 = NULL;
+          gtpu4_tunnel_key_t key4_0, key4_1;
+          gtpu6_tunnel_key_t key6_0, key6_1;
+          u32 error0, error1;
+	  u32 sw_if_index0, sw_if_index1, len0, len1;
+
+	  /* 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, LOAD);
+	    vlib_prefetch_buffer_header (p3, LOAD);
+
+	    CLIB_PREFETCH (p2->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
+	    CLIB_PREFETCH (p3->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
+	  }
+
+	  bi0 = from[0];
+	  bi1 = from[1];
+	  to_next[0] = bi0;
+	  to_next[1] = bi1;
+	  from += 2;
+	  to_next += 2;
+	  n_left_to_next -= 2;
+	  n_left_from -= 2;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b1 = vlib_get_buffer (vm, bi1);
+
+          /* udp leaves current_data pointing at the gtpu header */
+          gtpu0 = vlib_buffer_get_current (b0);
+          gtpu1 = vlib_buffer_get_current (b1);
+          if (is_ip4) {
+	    vlib_buffer_advance
+	      (b0, -(word)(sizeof(udp_header_t)+sizeof(ip4_header_t)));
+	    vlib_buffer_advance
+	      (b1, -(word)(sizeof(udp_header_t)+sizeof(ip4_header_t)));
+            ip4_0 = vlib_buffer_get_current (b0);
+            ip4_1 = vlib_buffer_get_current (b1);
+	  } else {
+            vlib_buffer_advance
+              (b0, -(word)(sizeof(udp_header_t)+sizeof(ip6_header_t)));
+            vlib_buffer_advance
+              (b1, -(word)(sizeof(udp_header_t)+sizeof(ip6_header_t)));
+            ip6_0 = vlib_buffer_get_current (b0);
+            ip6_1 = vlib_buffer_get_current (b1);
+	  }
+
+          /* pop (ip, udp, gtpu) */
+          if (is_ip4) {
+            vlib_buffer_advance
+              (b0, sizeof(*ip4_0)+sizeof(udp_header_t));
+	    vlib_buffer_advance
+              (b1, sizeof(*ip4_1)+sizeof(udp_header_t));
+          } else {
+	    vlib_buffer_advance
+              (b0, sizeof(*ip6_0)+sizeof(udp_header_t));
+            vlib_buffer_advance
+              (b1, sizeof(*ip6_1)+sizeof(udp_header_t));
+          }
+
+          tunnel_index0 = ~0;
+          error0 = 0;
+
+          tunnel_index1 = ~0;
+          error1 = 0;
+
+	  if (PREDICT_FALSE ((gtpu0->ver_flags & GTPU_VER_MASK) != GTPU_V1_VER))
+	    {
+	      error0 = GTPU_ERROR_BAD_VER;
+	      next0 = GTPU_INPUT_NEXT_DROP;
+	      goto trace0;
+	    }
+
+	  /* Manipulate packet 0 */
+          if (is_ip4) {
+            key4_0.src = ip4_0->src_address.as_u32;
+            key4_0.teid = gtpu0->teid;
+
+ 	    /* Make sure GTPU tunnel exist according to packet SIP and teid
+ 	     * SIP identify a GTPU path, and teid identify a tunnel in a given GTPU path */
+           if (PREDICT_FALSE (key4_0.as_u64 != last_key4.as_u64))
+              {
+                p0 = hash_get (gtm->gtpu4_tunnel_by_key, key4_0.as_u64);
+                if (PREDICT_FALSE (p0 == NULL))
+                  {
+                    error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+                    next0 = GTPU_INPUT_NEXT_DROP;
+                    goto trace0;
+                  }
+                last_key4.as_u64 = key4_0.as_u64;
+                tunnel_index0 = last_tunnel_index = p0[0];
+              }
+            else
+              tunnel_index0 = last_tunnel_index;
+	    t0 = pool_elt_at_index (gtm->tunnels, tunnel_index0);
+
+	    /* Validate GTPU tunnel encap-fib index agaist packet */
+	    if (PREDICT_FALSE (validate_gtpu_fib (b0, t0, is_ip4) == 0))
+	      {
+		error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+		next0 = GTPU_INPUT_NEXT_DROP;
+		goto trace0;
+	      }
+
+	    /* Validate GTPU tunnel SIP against packet DIP */
+	    if (PREDICT_TRUE (ip4_0->dst_address.as_u32 == t0->src.ip4.as_u32))
+	      goto next0; /* valid packet */
+	    if (PREDICT_FALSE (ip4_address_is_multicast (&ip4_0->dst_address)))
+	      {
+		key4_0.src = ip4_0->dst_address.as_u32;
+		key4_0.teid = gtpu0->teid;
+		/* Make sure mcast GTPU tunnel exist by packet DIP and teid */
+		p0 = hash_get (gtm->gtpu4_tunnel_by_key, key4_0.as_u64);
+		if (PREDICT_TRUE (p0 != NULL))
+		  {
+		    mt0 = pool_elt_at_index (gtm->tunnels, p0[0]);
+		    goto next0; /* valid packet */
+		  }
+	      }
+	    error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+	    next0 = GTPU_INPUT_NEXT_DROP;
+	    goto trace0;
+
+         } else /* !is_ip4 */ {
+            key6_0.src.as_u64[0] = ip6_0->src_address.as_u64[0];
+            key6_0.src.as_u64[1] = ip6_0->src_address.as_u64[1];
+            key6_0.teid = gtpu0->teid;
+
+ 	    /* Make sure GTPU tunnel exist according to packet SIP and teid
+ 	     * SIP identify a GTPU path, and teid identify a tunnel in a given GTPU path */
+            if (PREDICT_FALSE (memcmp(&key6_0, &last_key6, sizeof(last_key6)) != 0))
+              {
+                p0 = hash_get_mem (gtm->gtpu6_tunnel_by_key, &key6_0);
+                if (PREDICT_FALSE (p0 == NULL))
+                  {
+                    error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+                    next0 = GTPU_INPUT_NEXT_DROP;
+                    goto trace0;
+                  }
+                clib_memcpy (&last_key6, &key6_0, sizeof(key6_0));
+                tunnel_index0 = last_tunnel_index = p0[0];
+              }
+            else
+              tunnel_index0 = last_tunnel_index;
+	    t0 = pool_elt_at_index (gtm->tunnels, tunnel_index0);
+
+	    /* Validate GTPU tunnel encap-fib index agaist packet */
+	    if (PREDICT_FALSE (validate_gtpu_fib (b0, t0, is_ip4) == 0))
+	      {
+		error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+		next0 = GTPU_INPUT_NEXT_DROP;
+		goto trace0;
+	      }
+
+	    /* Validate GTPU tunnel SIP against packet DIP */
+	    if (PREDICT_TRUE (ip6_address_is_equal (&ip6_0->dst_address,
+						    &t0->src.ip6)))
+		goto next0; /* valid packet */
+	    if (PREDICT_FALSE (ip6_address_is_multicast (&ip6_0->dst_address)))
+	      {
+		key6_0.src.as_u64[0] = ip6_0->dst_address.as_u64[0];
+		key6_0.src.as_u64[1] = ip6_0->dst_address.as_u64[1];
+		key6_0.teid = gtpu0->teid;
+		p0 = hash_get_mem (gtm->gtpu6_tunnel_by_key, &key6_0);
+		if (PREDICT_TRUE (p0 != NULL))
+		  {
+		    mt0 = pool_elt_at_index (gtm->tunnels, p0[0]);
+		    goto next0; /* valid packet */
+		  }
+	      }
+	    error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+	    next0 = GTPU_INPUT_NEXT_DROP;
+	    goto trace0;
+          }
+
+	next0:
+	  /* Manipulate gtpu header */
+	  if (PREDICT_FALSE((gtpu0->ver_flags & GTPU_E_S_PN_BIT) != 0))
+	    {
+	      gtpu_hdr_len0 = sizeof(gtpu_header_t);
+
+	      /* Manipulate Sequence Number and N-PDU Number */
+	      /* TBD */
+
+	      /* Manipulate Next Extension Header */
+	      /* TBD */
+	    }
+	  else
+	    {
+	      gtpu_hdr_len0 = sizeof(gtpu_header_t) - 4;
+	    }
+
+	  /* Pop gtpu header */
+	  vlib_buffer_advance (b0, gtpu_hdr_len0);
+
+          next0 = t0->decap_next_index;
+          sw_if_index0 = t0->sw_if_index;
+          len0 = vlib_buffer_length_in_chain (vm, b0);
+
+          /* Required to make the l2 tag push / pop code work on l2 subifs */
+          if (PREDICT_TRUE(next0 == GTPU_INPUT_NEXT_L2_INPUT))
+            vnet_update_l2_len (b0);
+
+          /* Set packet input sw_if_index to unicast GTPU tunnel for learning */
+          vnet_buffer(b0)->sw_if_index[VLIB_RX] = sw_if_index0;
+	  sw_if_index0 = (mt0) ? mt0->sw_if_index : sw_if_index0;
+
+          pkts_decapsulated ++;
+          stats_n_packets += 1;
+          stats_n_bytes += len0;
+
+	  /* Batch stats increment on the same gtpu tunnel so counter
+	     is not incremented per packet */
+	  if (PREDICT_FALSE (sw_if_index0 != stats_sw_if_index))
+	    {
+	      stats_n_packets -= 1;
+	      stats_n_bytes -= len0;
+	      if (stats_n_packets)
+		vlib_increment_combined_counter
+		  (im->combined_sw_if_counters + VNET_INTERFACE_COUNTER_RX,
+		   thread_index, stats_sw_if_index,
+		   stats_n_packets, stats_n_bytes);
+	      stats_n_packets = 1;
+	      stats_n_bytes = len0;
+	      stats_sw_if_index = sw_if_index0;
+	    }
+
+        trace0:
+          b0->error = error0 ? node->errors[error0] : 0;
+
+          if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
+            {
+              gtpu_rx_trace_t *tr
+                = vlib_add_trace (vm, node, b0, sizeof (*tr));
+              tr->next_index = next0;
+              tr->error = error0;
+              tr->tunnel_index = tunnel_index0;
+              tr->teid = clib_net_to_host_u32(gtpu0->teid);
+            }
+
+          if (PREDICT_FALSE ((gtpu1->ver_flags & GTPU_VER_MASK) != GTPU_V1_VER))
+	    {
+	      error1 = GTPU_ERROR_BAD_VER;
+	      next1 = GTPU_INPUT_NEXT_DROP;
+	      goto trace1;
+	    }
+
+          /* Manipulate packet 1 */
+          if (is_ip4) {
+            key4_1.src = ip4_1->src_address.as_u32;
+            key4_1.teid = gtpu1->teid;
+
+ 	    /* Make sure GTPU tunnel exist according to packet SIP and teid
+ 	     * SIP identify a GTPU path, and teid identify a tunnel in a given GTPU path */
+	    if (PREDICT_FALSE (key4_1.as_u64 != last_key4.as_u64))
+              {
+                p1 = hash_get (gtm->gtpu4_tunnel_by_key, key4_1.as_u64);
+                if (PREDICT_FALSE (p1 == NULL))
+                  {
+                    error1 = GTPU_ERROR_NO_SUCH_TUNNEL;
+                    next1 = GTPU_INPUT_NEXT_DROP;
+                    goto trace1;
+                  }
+                last_key4.as_u64 = key4_1.as_u64;
+                tunnel_index1 = last_tunnel_index = p1[0];
+              }
+            else
+              tunnel_index1 = last_tunnel_index;
+ 	    t1 = pool_elt_at_index (gtm->tunnels, tunnel_index1);
+
+	    /* Validate GTPU tunnel encap-fib index agaist packet */
+	    if (PREDICT_FALSE (validate_gtpu_fib (b1, t1, is_ip4) == 0))
+	      {
+		error1 = GTPU_ERROR_NO_SUCH_TUNNEL;
+		next1 = GTPU_INPUT_NEXT_DROP;
+		goto trace1;
+	      }
+
+	    /* Validate GTPU tunnel SIP against packet DIP */
+	    if (PREDICT_TRUE (ip4_1->dst_address.as_u32 == t1->src.ip4.as_u32))
+	      goto next1; /* valid packet */
+	    if (PREDICT_FALSE (ip4_address_is_multicast (&ip4_1->dst_address)))
+	      {
+		key4_1.src = ip4_1->dst_address.as_u32;
+		key4_1.teid = gtpu1->teid;
+		/* Make sure mcast GTPU tunnel exist by packet DIP and teid */
+		p1 = hash_get (gtm->gtpu4_tunnel_by_key, key4_1.as_u64);
+		if (PREDICT_TRUE (p1 != NULL))
+		  {
+		    mt1 = pool_elt_at_index (gtm->tunnels, p1[0]);
+		    goto next1; /* valid packet */
+		  }
+	      }
+	    error1 = GTPU_ERROR_NO_SUCH_TUNNEL;
+	    next1 = GTPU_INPUT_NEXT_DROP;
+	    goto trace1;
+
+         } else /* !is_ip4 */ {
+            key6_1.src.as_u64[0] = ip6_1->src_address.as_u64[0];
+            key6_1.src.as_u64[1] = ip6_1->src_address.as_u64[1];
+            key6_1.teid = gtpu1->teid;
+
+ 	    /* Make sure GTPU tunnel exist according to packet SIP and teid
+ 	     * SIP identify a GTPU path, and teid identify a tunnel in a given GTPU path */
+            if (PREDICT_FALSE (memcmp(&key6_1, &last_key6, sizeof(last_key6)) != 0))
+              {
+                p1 = hash_get_mem (gtm->gtpu6_tunnel_by_key, &key6_1);
+
+                if (PREDICT_FALSE (p1 == NULL))
+                  {
+                    error1 = GTPU_ERROR_NO_SUCH_TUNNEL;
+                    next1 = GTPU_INPUT_NEXT_DROP;
+                    goto trace1;
+                  }
+
+                clib_memcpy (&last_key6, &key6_1, sizeof(key6_1));
+                tunnel_index1 = last_tunnel_index = p1[0];
+              }
+            else
+              tunnel_index1 = last_tunnel_index;
+ 	    t1 = pool_elt_at_index (gtm->tunnels, tunnel_index1);
+
+	    /* Validate GTPU tunnel encap-fib index agaist packet */
+	    if (PREDICT_FALSE (validate_gtpu_fib (b1, t1, is_ip4) == 0))
+	      {
+		error1 = GTPU_ERROR_NO_SUCH_TUNNEL;
+		next1 = GTPU_INPUT_NEXT_DROP;
+		goto trace1;
+	      }
+
+	    /* Validate GTPU tunnel SIP against packet DIP */
+	    if (PREDICT_TRUE (ip6_address_is_equal (&ip6_1->dst_address,
+						    &t1->src.ip6)))
+		goto next1; /* valid packet */
+	    if (PREDICT_FALSE (ip6_address_is_multicast (&ip6_1->dst_address)))
+	      {
+		key6_1.src.as_u64[0] = ip6_1->dst_address.as_u64[0];
+		key6_1.src.as_u64[1] = ip6_1->dst_address.as_u64[1];
+		key6_1.teid = gtpu1->teid;
+		p1 = hash_get_mem (gtm->gtpu6_tunnel_by_key, &key6_1);
+		if (PREDICT_TRUE (p1 != NULL))
+		  {
+		    mt1 = pool_elt_at_index (gtm->tunnels, p1[0]);
+		    goto next1; /* valid packet */
+		  }
+	      }
+	    error1 = GTPU_ERROR_NO_SUCH_TUNNEL;
+	    next1 = GTPU_INPUT_NEXT_DROP;
+	    goto trace1;
+	  }
+
+	next1:
+	  /* Manipulate gtpu header */
+	  if (PREDICT_FALSE((gtpu1->ver_flags & GTPU_E_S_PN_BIT) != 0))
+	    {
+	      gtpu_hdr_len1 = sizeof(gtpu_header_t);
+
+	      /* Manipulate Sequence Number and N-PDU Number */
+	      /* TBD */
+
+	      /* Manipulate Next Extension Header */
+	      /* TBD */
+	    }
+	  else
+	    {
+	      gtpu_hdr_len1 = sizeof(gtpu_header_t) - 4;
+	    }
+
+	  /* Pop gtpu header */
+	  vlib_buffer_advance (b1, gtpu_hdr_len1);
+
+          next1 = t1->decap_next_index;
+          sw_if_index1 = t1->sw_if_index;
+          len1 = vlib_buffer_length_in_chain (vm, b1);
+
+          /* Required to make the l2 tag push / pop code work on l2 subifs */
+          if (PREDICT_TRUE(next1 == GTPU_INPUT_NEXT_L2_INPUT))
+            vnet_update_l2_len (b1);
+
+          /* Set packet input sw_if_index to unicast GTPU tunnel for learning */
+          vnet_buffer(b1)->sw_if_index[VLIB_RX] = sw_if_index1;
+	  sw_if_index1 = (mt1) ? mt1->sw_if_index : sw_if_index1;
+
+          pkts_decapsulated ++;
+          stats_n_packets += 1;
+          stats_n_bytes += len1;
+
+	  /* Batch stats increment on the same gtpu tunnel so counter
+	     is not incremented per packet */
+	  if (PREDICT_FALSE (sw_if_index1 != stats_sw_if_index))
+	    {
+	      stats_n_packets -= 1;
+	      stats_n_bytes -= len1;
+	      if (stats_n_packets)
+		vlib_increment_combined_counter
+		  (im->combined_sw_if_counters + VNET_INTERFACE_COUNTER_RX,
+		   thread_index, stats_sw_if_index,
+		   stats_n_packets, stats_n_bytes);
+	      stats_n_packets = 1;
+	      stats_n_bytes = len1;
+	      stats_sw_if_index = sw_if_index1;
+	    }
+
+        trace1:
+          b1->error = error1 ? node->errors[error1] : 0;
+
+          if (PREDICT_FALSE(b1->flags & VLIB_BUFFER_IS_TRACED))
+            {
+              gtpu_rx_trace_t *tr
+                = vlib_add_trace (vm, node, b1, sizeof (*tr));
+              tr->next_index = next1;
+              tr->error = error1;
+              tr->tunnel_index = tunnel_index1;
+              tr->teid = clib_net_to_host_u32(gtpu1->teid);
+            }
+
+	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, bi1, next0, next1);
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t * b0;
+	  u32 next0;
+          ip4_header_t * ip4_0;
+          ip6_header_t * ip6_0;
+          gtpu_header_t * gtpu0;
+          u32 gtpu_hdr_len0 = 0;
+	  uword * p0;
+          u32 tunnel_index0;
+          gtpu_tunnel_t * t0, * mt0 = NULL;
+          gtpu4_tunnel_key_t key4_0;
+          gtpu6_tunnel_key_t key6_0;
+          u32 error0;
+	  u32 sw_if_index0, len0;
+
+	  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);
+
+          /* udp leaves current_data pointing at the gtpu header */
+          gtpu0 = vlib_buffer_get_current (b0);
+          if (is_ip4) {
+	    vlib_buffer_advance
+	      (b0, -(word)(sizeof(udp_header_t)+sizeof(ip4_header_t)));
+            ip4_0 = vlib_buffer_get_current (b0);
+          } else {
+            vlib_buffer_advance
+              (b0, -(word)(sizeof(udp_header_t)+sizeof(ip6_header_t)));
+            ip6_0 = vlib_buffer_get_current (b0);
+          }
+
+          /* pop (ip, udp) */
+          if (is_ip4) {
+            vlib_buffer_advance
+              (b0, sizeof(*ip4_0)+sizeof(udp_header_t));
+          } else {
+	    vlib_buffer_advance
+              (b0, sizeof(*ip6_0)+sizeof(udp_header_t));
+          }
+
+          tunnel_index0 = ~0;
+          error0 = 0;
+          if (PREDICT_FALSE ((gtpu0->ver_flags & GTPU_VER_MASK) != GTPU_V1_VER))
+	    {
+	      error0 = GTPU_ERROR_BAD_VER;
+	      next0 = GTPU_INPUT_NEXT_DROP;
+	      goto trace00;
+	    }
+
+          if (is_ip4) {
+            key4_0.src = ip4_0->src_address.as_u32;
+            key4_0.teid = gtpu0->teid;
+
+ 	    /* Make sure GTPU tunnel exist according to packet SIP and teid
+ 	     * SIP identify a GTPU path, and teid identify a tunnel in a given GTPU path */
+            if (PREDICT_FALSE (key4_0.as_u64 != last_key4.as_u64))
+              {
+                p0 = hash_get (gtm->gtpu4_tunnel_by_key, key4_0.as_u64);
+                if (PREDICT_FALSE (p0 == NULL))
+                  {
+                    error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+                    next0 = GTPU_INPUT_NEXT_DROP;
+                    goto trace00;
+                  }
+                last_key4.as_u64 = key4_0.as_u64;
+                tunnel_index0 = last_tunnel_index = p0[0];
+              }
+            else
+              tunnel_index0 = last_tunnel_index;
+	    t0 = pool_elt_at_index (gtm->tunnels, tunnel_index0);
+
+	    /* Validate GTPU tunnel encap-fib index agaist packet */
+	    if (PREDICT_FALSE (validate_gtpu_fib (b0, t0, is_ip4) == 0))
+	      {
+		error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+		next0 = GTPU_INPUT_NEXT_DROP;
+		goto trace00;
+	      }
+
+	    /* Validate GTPU tunnel SIP against packet DIP */
+	    if (PREDICT_TRUE (ip4_0->dst_address.as_u32 == t0->src.ip4.as_u32))
+	      goto next00; /* valid packet */
+	    if (PREDICT_FALSE (ip4_address_is_multicast (&ip4_0->dst_address)))
+	      {
+		key4_0.src = ip4_0->dst_address.as_u32;
+		key4_0.teid = gtpu0->teid;
+		/* Make sure mcast GTPU tunnel exist by packet DIP and teid */
+		p0 = hash_get (gtm->gtpu4_tunnel_by_key, key4_0.as_u64);
+		if (PREDICT_TRUE (p0 != NULL))
+		  {
+		    mt0 = pool_elt_at_index (gtm->tunnels, p0[0]);
+		    goto next00; /* valid packet */
+		  }
+	      }
+	    error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+	    next0 = GTPU_INPUT_NEXT_DROP;
+	    goto trace00;
+
+          } else /* !is_ip4 */ {
+            key6_0.src.as_u64[0] = ip6_0->src_address.as_u64[0];
+            key6_0.src.as_u64[1] = ip6_0->src_address.as_u64[1];
+            key6_0.teid = gtpu0->teid;
+
+ 	    /* Make sure GTPU tunnel exist according to packet SIP and teid
+ 	     * SIP identify a GTPU path, and teid identify a tunnel in a given GTPU path */
+            if (PREDICT_FALSE (memcmp(&key6_0, &last_key6, sizeof(last_key6)) != 0))
+              {
+                p0 = hash_get_mem (gtm->gtpu6_tunnel_by_key, &key6_0);
+                if (PREDICT_FALSE (p0 == NULL))
+                  {
+                    error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+                    next0 = GTPU_INPUT_NEXT_DROP;
+                    goto trace00;
+                  }
+                clib_memcpy (&last_key6, &key6_0, sizeof(key6_0));
+                tunnel_index0 = last_tunnel_index = p0[0];
+              }
+            else
+              tunnel_index0 = last_tunnel_index;
+	    t0 = pool_elt_at_index (gtm->tunnels, tunnel_index0);
+
+	    /* Validate GTPU tunnel encap-fib index agaist packet */
+	    if (PREDICT_FALSE (validate_gtpu_fib (b0, t0, is_ip4) == 0))
+	      {
+		error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+		next0 = GTPU_INPUT_NEXT_DROP;
+		goto trace00;
+	      }
+
+	    /* Validate GTPU tunnel SIP against packet DIP */
+	    if (PREDICT_TRUE (ip6_address_is_equal (&ip6_0->dst_address,
+						    &t0->src.ip6)))
+		goto next00; /* valid packet */
+	    if (PREDICT_FALSE (ip6_address_is_multicast (&ip6_0->dst_address)))
+	      {
+		key6_0.src.as_u64[0] = ip6_0->dst_address.as_u64[0];
+		key6_0.src.as_u64[1] = ip6_0->dst_address.as_u64[1];
+		key6_0.teid = gtpu0->teid;
+		p0 = hash_get_mem (gtm->gtpu6_tunnel_by_key, &key6_0);
+		if (PREDICT_TRUE (p0 != NULL))
+		  {
+		    mt0 = pool_elt_at_index (gtm->tunnels, p0[0]);
+		    goto next00; /* valid packet */
+		  }
+	      }
+	    error0 = GTPU_ERROR_NO_SUCH_TUNNEL;
+	    next0 = GTPU_INPUT_NEXT_DROP;
+	    goto trace00;
+          }
+
+	next00:
+	  /* Manipulate gtpu header */
+	  if (PREDICT_FALSE((gtpu0->ver_flags & GTPU_E_S_PN_BIT) != 0))
+	    {
+	      gtpu_hdr_len0 = sizeof(gtpu_header_t);
+
+	      /* Manipulate Sequence Number and N-PDU Number */
+	      /* TBD */
+
+	      /* Manipulate Next Extension Header */
+	      /* TBD */
+	    }
+	  else
+	    {
+	      gtpu_hdr_len0 = sizeof(gtpu_header_t) - 4;
+	    }
+
+	  /* Pop gtpu header */
+	  vlib_buffer_advance (b0, gtpu_hdr_len0);
+
+	  next0 = t0->decap_next_index;
+	  sw_if_index0 = t0->sw_if_index;
+	  len0 = vlib_buffer_length_in_chain (vm, b0);
+
+          /* Required to make the l2 tag push / pop code work on l2 subifs */
+          if (PREDICT_TRUE(next0 == GTPU_INPUT_NEXT_L2_INPUT))
+            vnet_update_l2_len (b0);
+
+          /* Set packet input sw_if_index to unicast GTPU tunnel for learning */
+          vnet_buffer(b0)->sw_if_index[VLIB_RX] = sw_if_index0;
+	  sw_if_index0 = (mt0) ? mt0->sw_if_index : sw_if_index0;
+
+          pkts_decapsulated ++;
+          stats_n_packets += 1;
+          stats_n_bytes += len0;
+
+	  /* Batch stats increment on the same gtpu tunnel so counter
+	     is not incremented per packet */
+	  if (PREDICT_FALSE (sw_if_index0 != stats_sw_if_index))
+	    {
+	      stats_n_packets -= 1;
+	      stats_n_bytes -= len0;
+	      if (stats_n_packets)
+		vlib_increment_combined_counter
+		  (im->combined_sw_if_counters + VNET_INTERFACE_COUNTER_RX,
+		   thread_index, stats_sw_if_index,
+		   stats_n_packets, stats_n_bytes);
+	      stats_n_packets = 1;
+	      stats_n_bytes = len0;
+	      stats_sw_if_index = sw_if_index0;
+	    }
+
+        trace00:
+          b0->error = error0 ? node->errors[error0] : 0;
+
+          if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
+            {
+              gtpu_rx_trace_t *tr
+                = vlib_add_trace (vm, node, b0, sizeof (*tr));
+              tr->next_index = next0;
+              tr->error = error0;
+              tr->tunnel_index = tunnel_index0;
+              tr->teid = clib_net_to_host_u32(gtpu0->teid);
+            }
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+  /* Do we still need this now that tunnel tx stats is kept? */
+  vlib_node_increment_counter (vm, is_ip4?
+			       gtpu4_input_node.index:gtpu6_input_node.index,
+                               GTPU_ERROR_DECAPSULATED,
+                               pkts_decapsulated);
+
+  /* Increment any remaining batch stats */
+  if (stats_n_packets)
+    {
+      vlib_increment_combined_counter
+	(im->combined_sw_if_counters + VNET_INTERFACE_COUNTER_RX,
+	 thread_index, stats_sw_if_index, stats_n_packets, stats_n_bytes);
+      node->runtime_data[0] = stats_sw_if_index;
+    }
+
+  return from_frame->n_vectors;
+}
+
+static uword
+gtpu4_input (vlib_main_t * vm,
+             vlib_node_runtime_t * node,
+             vlib_frame_t * from_frame)
+{
+	return gtpu_input(vm, node, from_frame, /* is_ip4 */ 1);
+}
+
+static uword
+gtpu6_input (vlib_main_t * vm,
+             vlib_node_runtime_t * node,
+             vlib_frame_t * from_frame)
+{
+	return gtpu_input(vm, node, from_frame, /* is_ip4 */ 0);
+}
+
+static char * gtpu_error_strings[] = {
+#define gtpu_error(n,s) s,
+#include <gtpu/gtpu_error.def>
+#undef gtpu_error
+#undef _
+};
+
+VLIB_REGISTER_NODE (gtpu4_input_node) = {
+  .function = gtpu4_input,
+  .name = "gtpu4-input",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+
+  .n_errors = GTPU_N_ERROR,
+  .error_strings = gtpu_error_strings,
+
+  .n_next_nodes = GTPU_INPUT_N_NEXT,
+  .next_nodes = {
+#define _(s,n) [GTPU_INPUT_NEXT_##s] = n,
+    foreach_gtpu_input_next
+#undef _
+  },
+
+//temp  .format_buffer = format_gtpu_header,
+  .format_trace = format_gtpu_rx_trace,
+  // $$$$ .unformat_buffer = unformat_gtpu_header,
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (gtpu4_input_node, gtpu4_input)
+
+VLIB_REGISTER_NODE (gtpu6_input_node) = {
+  .function = gtpu6_input,
+  .name = "gtpu6-input",
+  /* Takes a vector of packets. */
+  .vector_size = sizeof (u32),
+
+  .n_errors = GTPU_N_ERROR,
+  .error_strings = gtpu_error_strings,
+
+  .n_next_nodes = GTPU_INPUT_N_NEXT,
+  .next_nodes = {
+#define _(s,n) [GTPU_INPUT_NEXT_##s] = n,
+    foreach_gtpu_input_next
+#undef _
+  },
+
+//temp  .format_buffer = format_gtpu_header,
+  .format_trace = format_gtpu_rx_trace,
+  // $$$$ .unformat_buffer = unformat_gtpu_header,
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (gtpu6_input_node, gtpu6_input)
+
+
+typedef enum {
+  IP_GTPU_BYPASS_NEXT_DROP,
+  IP_GTPU_BYPASS_NEXT_GTPU,
+  IP_GTPU_BYPASS_N_NEXT,
+} ip_vxan_bypass_next_t;
+
+always_inline uword
+ip_gtpu_bypass_inline (vlib_main_t * vm,
+			vlib_node_runtime_t * node,
+			vlib_frame_t * frame,
+			u32 is_ip4)
+{
+  gtpu_main_t * gtm = &gtpu_main;
+  u32 * from, * to_next, n_left_from, n_left_to_next, next_index;
+  vlib_node_runtime_t * error_node = vlib_node_get_runtime (vm, ip4_input_node.index);
+  ip4_address_t addr4; /* last IPv4 address matching a local VTEP address */
+  ip6_address_t addr6; /* last IPv6 address matching a local VTEP address */
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  if (node->flags & VLIB_NODE_FLAG_TRACE)
+    ip4_forward_next_trace (vm, node, frame, VLIB_TX);
+
+  if (is_ip4) addr4.data_u32 = ~0;
+  else ip6_address_set_zero (&addr6);
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from >= 4 && n_left_to_next >= 2)
+      	{
+      	  vlib_buffer_t * b0, * b1;
+      	  ip4_header_t * ip40, * ip41;
+      	  ip6_header_t * ip60, * ip61;
+      	  udp_header_t * udp0, * udp1;
+      	  u32 bi0, ip_len0, udp_len0, flags0, next0;
+      	  u32 bi1, ip_len1, udp_len1, flags1, next1;
+      	  i32 len_diff0, len_diff1;
+      	  u8 error0, good_udp0, proto0;
+      	  u8 error1, good_udp1, proto1;
+
+	  /* 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, LOAD);
+	    vlib_prefetch_buffer_header (p3, LOAD);
+
+	    CLIB_PREFETCH (p2->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
+	    CLIB_PREFETCH (p3->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
+	  }
+
+      	  bi0 = to_next[0] = from[0];
+      	  bi1 = to_next[1] = from[1];
+      	  from += 2;
+      	  n_left_from -= 2;
+      	  to_next += 2;
+      	  n_left_to_next -= 2;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b1 = vlib_get_buffer (vm, bi1);
+	  if (is_ip4)
+	    {
+	      ip40 = vlib_buffer_get_current (b0);
+	      ip41 = vlib_buffer_get_current (b1);
+	    }
+	  else
+	    {
+	      ip60 = vlib_buffer_get_current (b0);
+	      ip61 = vlib_buffer_get_current (b1);
+	    }
+
+	  /* Setup packet for next IP feature */
+	  vnet_feature_next(vnet_buffer(b0)->sw_if_index[VLIB_RX], &next0, b0);
+	  vnet_feature_next(vnet_buffer(b1)->sw_if_index[VLIB_RX], &next1, b1);
+
+	  if (is_ip4)
+	    {
+	      /* Treat IP frag packets as "experimental" protocol for now
+		 until support of IP frag reassembly is implemented */
+	      proto0 = ip4_is_fragment(ip40) ? 0xfe : ip40->protocol;
+	      proto1 = ip4_is_fragment(ip41) ? 0xfe : ip41->protocol;
+	    }
+	  else
+	    {
+	      proto0 = ip60->protocol;
+	      proto1 = ip61->protocol;
+	    }
+
+	  /* Process packet 0 */
+	  if (proto0 != IP_PROTOCOL_UDP)
+	    goto exit0; /* not UDP packet */
+
+	  if (is_ip4)
+	    udp0 = ip4_next_header (ip40);
+	  else
+	    udp0 = ip6_next_header (ip60);
+
+	  if (udp0->dst_port != clib_host_to_net_u16 (UDP_DST_PORT_GTPU))
+	    goto exit0; /* not GTPU packet */
+
+	  /* Validate DIP against VTEPs*/
+	  if (is_ip4)
+	    {
+	      if (addr4.as_u32 != ip40->dst_address.as_u32)
+	        {
+		  if (!hash_get (gtm->vtep4, ip40->dst_address.as_u32))
+		      goto exit0; /* no local VTEP for GTPU packet */
+		  addr4 = ip40->dst_address;
+	        }
+	    }
+	  else
+	    {
+	      if (!ip6_address_is_equal (&addr6, &ip60->dst_address))
+	        {
+		  if (!hash_get_mem (gtm->vtep6, &ip60->dst_address))
+		      goto exit0; /* no local VTEP for GTPU packet */
+		  addr6 = ip60->dst_address;
+	        }
+	    }
+
+	  flags0 = b0->flags;
+	  good_udp0 = (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+
+	  /* Don't verify UDP checksum for packets with explicit zero checksum. */
+	  good_udp0 |= udp0->checksum == 0;
+
+	  /* Verify UDP length */
+	  if (is_ip4)
+	    ip_len0 = clib_net_to_host_u16 (ip40->length);
+	  else
+	    ip_len0 = clib_net_to_host_u16 (ip60->payload_length);
+	  udp_len0 = clib_net_to_host_u16 (udp0->length);
+	  len_diff0 = ip_len0 - udp_len0;
+
+	  /* Verify UDP checksum */
+	  if (PREDICT_FALSE (!good_udp0))
+	    {
+	      if ((flags0 & IP_BUFFER_L4_CHECKSUM_COMPUTED) == 0)
+	        {
+		  if (is_ip4)
+		    flags0 = ip4_tcp_udp_validate_checksum (vm, b0);
+		  else
+		    flags0 = ip6_tcp_udp_icmp_validate_checksum (vm, b0);
+		  good_udp0 =
+		    (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+	        }
+	    }
+
+	  if (is_ip4)
+	    {
+	      error0 = good_udp0 ? 0 : IP4_ERROR_UDP_CHECKSUM;
+	      error0 = (len_diff0 >= 0) ? error0 : IP4_ERROR_UDP_LENGTH;
+	    }
+	  else
+	    {
+	      error0 = good_udp0 ? 0 : IP6_ERROR_UDP_CHECKSUM;
+	      error0 = (len_diff0 >= 0) ? error0 : IP6_ERROR_UDP_LENGTH;
+	    }
+
+	  next0 = error0 ?
+	    IP_GTPU_BYPASS_NEXT_DROP : IP_GTPU_BYPASS_NEXT_GTPU;
+	  b0->error = error0 ? error_node->errors[error0] : 0;
+
+	  /* gtpu-input node expect current at GTPU header */
+	  if (is_ip4)
+	    vlib_buffer_advance (b0, sizeof(ip4_header_t)+sizeof(udp_header_t));
+	  else
+	    vlib_buffer_advance (b0, sizeof(ip6_header_t)+sizeof(udp_header_t));
+
+	exit0:
+	  /* Process packet 1 */
+	  if (proto1 != IP_PROTOCOL_UDP)
+	    goto exit1; /* not UDP packet */
+
+	  if (is_ip4)
+	    udp1 = ip4_next_header (ip41);
+	  else
+	    udp1 = ip6_next_header (ip61);
+
+	  if (udp1->dst_port != clib_host_to_net_u16 (UDP_DST_PORT_GTPU))
+	    goto exit1; /* not GTPU packet */
+
+	  /* Validate DIP against VTEPs*/
+	  if (is_ip4)
+	    {
+	      if (addr4.as_u32 != ip41->dst_address.as_u32)
+	        {
+		  if (!hash_get (gtm->vtep4, ip41->dst_address.as_u32))
+		      goto exit1; /* no local VTEP for GTPU packet */
+		  addr4 = ip41->dst_address;
+		}
+	    }
+	  else
+	    {
+	      if (!ip6_address_is_equal (&addr6, &ip61->dst_address))
+	        {
+		  if (!hash_get_mem (gtm->vtep6, &ip61->dst_address))
+		      goto exit1; /* no local VTEP for GTPU packet */
+		  addr6 = ip61->dst_address;
+		}
+	    }
+
+	  flags1 = b1->flags;
+	  good_udp1 = (flags1 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+
+	  /* Don't verify UDP checksum for packets with explicit zero checksum. */
+	  good_udp1 |= udp1->checksum == 0;
+
+	  /* Verify UDP length */
+	  if (is_ip4)
+	    ip_len1 = clib_net_to_host_u16 (ip41->length);
+	  else
+	    ip_len1 = clib_net_to_host_u16 (ip61->payload_length);
+	  udp_len1 = clib_net_to_host_u16 (udp1->length);
+	  len_diff1 = ip_len1 - udp_len1;
+
+	  /* Verify UDP checksum */
+	  if (PREDICT_FALSE (!good_udp1))
+	    {
+	      if ((flags1 & IP_BUFFER_L4_CHECKSUM_COMPUTED) == 0)
+	        {
+		  if (is_ip4)
+		    flags1 = ip4_tcp_udp_validate_checksum (vm, b1);
+		  else
+		    flags1 = ip6_tcp_udp_icmp_validate_checksum (vm, b1);
+		  good_udp1 =
+		    (flags1 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+	        }
+	    }
+
+	  if (is_ip4)
+	    {
+	      error1 = good_udp1 ? 0 : IP4_ERROR_UDP_CHECKSUM;
+	      error1 = (len_diff1 >= 0) ? error1 : IP4_ERROR_UDP_LENGTH;
+	    }
+	  else
+	    {
+	      error1 = good_udp1 ? 0 : IP6_ERROR_UDP_CHECKSUM;
+	      error1 = (len_diff1 >= 0) ? error1 : IP6_ERROR_UDP_LENGTH;
+	    }
+
+	  next1 = error1 ?
+	    IP_GTPU_BYPASS_NEXT_DROP : IP_GTPU_BYPASS_NEXT_GTPU;
+	  b1->error = error1 ? error_node->errors[error1] : 0;
+
+	  /* gtpu-input node expect current at GTPU header */
+	  if (is_ip4)
+	    vlib_buffer_advance (b1, sizeof(ip4_header_t)+sizeof(udp_header_t));
+	  else
+	    vlib_buffer_advance (b1, sizeof(ip6_header_t)+sizeof(udp_header_t));
+
+	exit1:
+	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, bi1, next0, next1);
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  vlib_buffer_t * b0;
+	  ip4_header_t * ip40;
+	  ip6_header_t * ip60;
+	  udp_header_t * udp0;
+      	  u32 bi0, ip_len0, udp_len0, flags0, next0;
+	  i32 len_diff0;
+	  u8 error0, good_udp0, proto0;
+
+	  bi0 = to_next[0] = from[0];
+	  from += 1;
+	  n_left_from -= 1;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  if (is_ip4)
+	    ip40 = vlib_buffer_get_current (b0);
+	  else
+	    ip60 = vlib_buffer_get_current (b0);
+
+	  /* Setup packet for next IP feature */
+	  vnet_feature_next(vnet_buffer(b0)->sw_if_index[VLIB_RX], &next0, b0);
+
+	  if (is_ip4)
+	    /* Treat IP4 frag packets as "experimental" protocol for now
+	       until support of IP frag reassembly is implemented */
+	    proto0 = ip4_is_fragment(ip40) ? 0xfe : ip40->protocol;
+	  else
+	    proto0 = ip60->protocol;
+
+	  if (proto0 != IP_PROTOCOL_UDP)
+	    goto exit; /* not UDP packet */
+
+	  if (is_ip4)
+	    udp0 = ip4_next_header (ip40);
+	  else
+	    udp0 = ip6_next_header (ip60);
+
+	  if (udp0->dst_port != clib_host_to_net_u16 (UDP_DST_PORT_GTPU))
+	    goto exit; /* not GTPU packet */
+
+	  /* Validate DIP against VTEPs*/
+	  if (is_ip4)
+	    {
+	      if (addr4.as_u32 != ip40->dst_address.as_u32)
+	        {
+		  if (!hash_get (gtm->vtep4, ip40->dst_address.as_u32))
+		      goto exit; /* no local VTEP for GTPU packet */
+		  addr4 = ip40->dst_address;
+		}
+	    }
+	  else
+	    {
+	      if (!ip6_address_is_equal (&addr6, &ip60->dst_address))
+	        {
+		  if (!hash_get_mem (gtm->vtep6, &ip60->dst_address))
+		      goto exit; /* no local VTEP for GTPU packet */
+		  addr6 = ip60->dst_address;
+		}
+	    }
+
+	  flags0 = b0->flags;
+	  good_udp0 = (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+
+	  /* Don't verify UDP checksum for packets with explicit zero checksum. */
+	  good_udp0 |= udp0->checksum == 0;
+
+	  /* Verify UDP length */
+	  if (is_ip4)
+	    ip_len0 = clib_net_to_host_u16 (ip40->length);
+	  else
+	    ip_len0 = clib_net_to_host_u16 (ip60->payload_length);
+	  udp_len0 = clib_net_to_host_u16 (udp0->length);
+	  len_diff0 = ip_len0 - udp_len0;
+
+	  /* Verify UDP checksum */
+	  if (PREDICT_FALSE (!good_udp0))
+	    {
+	      if ((flags0 & IP_BUFFER_L4_CHECKSUM_COMPUTED) == 0)
+	        {
+		  if (is_ip4)
+		    flags0 = ip4_tcp_udp_validate_checksum (vm, b0);
+		  else
+		    flags0 = ip6_tcp_udp_icmp_validate_checksum (vm, b0);
+		  good_udp0 =
+		    (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
+	        }
+	    }
+
+	  if (is_ip4)
+	    {
+	      error0 = good_udp0 ? 0 : IP4_ERROR_UDP_CHECKSUM;
+	      error0 = (len_diff0 >= 0) ? error0 : IP4_ERROR_UDP_LENGTH;
+	    }
+	  else
+	    {
+	      error0 = good_udp0 ? 0 : IP6_ERROR_UDP_CHECKSUM;
+	      error0 = (len_diff0 >= 0) ? error0 : IP6_ERROR_UDP_LENGTH;
+	    }
+
+	  next0 = error0 ?
+	    IP_GTPU_BYPASS_NEXT_DROP : IP_GTPU_BYPASS_NEXT_GTPU;
+	  b0->error = error0 ? error_node->errors[error0] : 0;
+
+	  /* gtpu-input node expect current at GTPU header */
+	  if (is_ip4)
+	    vlib_buffer_advance (b0, sizeof(ip4_header_t)+sizeof(udp_header_t));
+	  else
+	    vlib_buffer_advance (b0, sizeof(ip6_header_t)+sizeof(udp_header_t));
+
+	exit:
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  return frame->n_vectors;
+}
+
+static uword
+ip4_gtpu_bypass (vlib_main_t * vm,
+		  vlib_node_runtime_t * node,
+		  vlib_frame_t * frame)
+{
+  return ip_gtpu_bypass_inline (vm, node, frame, /* is_ip4 */ 1);
+}
+
+VLIB_REGISTER_NODE (ip4_gtpu_bypass_node) = {
+  .function = ip4_gtpu_bypass,
+  .name = "ip4-gtpu-bypass",
+  .vector_size = sizeof (u32),
+
+  .n_next_nodes = IP_GTPU_BYPASS_N_NEXT,
+  .next_nodes = {
+    [IP_GTPU_BYPASS_NEXT_DROP] = "error-drop",
+    [IP_GTPU_BYPASS_NEXT_GTPU] = "gtpu4-input",
+  },
+
+  .format_buffer = format_ip4_header,
+  .format_trace = format_ip4_forward_next_trace,
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip4_gtpu_bypass_node,ip4_gtpu_bypass)
+
+/* Dummy init function to get us linked in. */
+clib_error_t * ip4_gtpu_bypass_init (vlib_main_t * vm)
+{ return 0; }
+
+VLIB_INIT_FUNCTION (ip4_gtpu_bypass_init);
+
+static uword
+ip6_gtpu_bypass (vlib_main_t * vm,
+		  vlib_node_runtime_t * node,
+		  vlib_frame_t * frame)
+{
+  return ip_gtpu_bypass_inline (vm, node, frame, /* is_ip4 */ 0);
+}
+
+VLIB_REGISTER_NODE (ip6_gtpu_bypass_node) = {
+  .function = ip6_gtpu_bypass,
+  .name = "ip6-gtpu-bypass",
+  .vector_size = sizeof (u32),
+
+  .n_next_nodes = IP_GTPU_BYPASS_N_NEXT,
+  .next_nodes = {
+    [IP_GTPU_BYPASS_NEXT_DROP] = "error-drop",
+    [IP_GTPU_BYPASS_NEXT_GTPU] = "gtpu6-input",
+  },
+
+  .format_buffer = format_ip6_header,
+  .format_trace = format_ip6_forward_next_trace,
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip6_gtpu_bypass_node,ip6_gtpu_bypass)
+
+/* Dummy init function to get us linked in. */
+clib_error_t * ip6_gtpu_bypass_init (vlib_main_t * vm)
+{ return 0; }
+
+VLIB_INIT_FUNCTION (ip6_gtpu_bypass_init);