UDP Encapsulation.

A UDP-encap object that particiapates in the FIB graph and contributes
DPO to teh output chain. It thereofre resembles a tunnel but without the
interface. FIB paths (and henace routes) can then be created to egress
through the UDP-encap. Said routes can have MPLS labels, hence this also
allows MPLSoUPD.
Encap is uni-directional. For decap, one still registers with the UDP port
dispatcher.

Change-Id: I23bd345523b20789a1de1b02022ea1148ca50797
Signed-off-by: Neale Ranns <nranns@cisco.com>

14 files changed, 1422 insertions, 6 deletions

diff --git a/src/vnet/fib/fib_api.h b/src/vnet/fib/fib_api.h
index e5b94e14124..655d305372b 100644
--- a/src/vnet/fib/fib_api.h
+++ b/src/vnet/fib/fib_api.h
@@ -42,10 +42,12 @@ add_del_route_t_handler (u8 is_multipath,
                          u8 is_rpf_id,
                          u8 is_l2_bridged,
                          u8 is_source_lookup,
+                         u8 is_udp_encap,
 			 u32 fib_index,
 			 const fib_prefix_t * prefix,
 			 dpo_proto_t next_hop_proto,
 			 const ip46_address_t * next_hop,
+                         u32 next_hop_id,
 			 u32 next_hop_sw_if_index,
 			 u8 next_hop_fib_index,
 			 u16 next_hop_weight,
diff --git a/src/vnet/fib/fib_node.h b/src/vnet/fib/fib_node.h
index 762e0cf01af..6d26bdd3671 100644
--- a/src/vnet/fib/fib_node.h
+++ b/src/vnet/fib/fib_node.h
@@ -44,6 +44,7 @@ typedef enum fib_node_type_t_ {
     FIB_NODE_TYPE_MAP_E,
     FIB_NODE_TYPE_VXLAN_GPE_TUNNEL,
     FIB_NODE_TYPE_GENEVE_TUNNEL,
+    FIB_NODE_TYPE_UDP_ENCAP,
     /**
      * Marker. New types before this one. leave the test last.
      */
@@ -68,6 +69,7 @@ typedef enum fib_node_type_t_ {
     [FIB_NODE_TYPE_VXLAN_TUNNEL] = "vxlan-tunnel", \
     [FIB_NODE_TYPE_MAP_E] = "map-e", \
     [FIB_NODE_TYPE_VXLAN_GPE_TUNNEL] = "vxlan-gpe-tunnel", \
+    [FIB_NODE_TYPE_UDP_ENCAP] = "udp-encap", \
 }
 
 /**
diff --git a/src/vnet/fib/fib_path.c b/src/vnet/fib/fib_path.c
index 926b2f3dfc6..4fccca80672 100644
--- a/src/vnet/fib/fib_path.c
+++ b/src/vnet/fib/fib_path.c
@@ -36,6 +36,7 @@
 #include <vnet/fib/fib_internal.h>
 #include <vnet/fib/fib_urpf_list.h>
 #include <vnet/fib/mpls_fib.h>
+#include <vnet/udp/udp_encap.h>
 
 /**
  * Enurmeration of path types
@@ -74,6 +75,10 @@ typedef enum fib_path_type_t_ {
      */
     FIB_PATH_TYPE_INTF_RX,
     /**
+     * interface receive.
+     */
+    FIB_PATH_TYPE_UDP_ENCAP,
+    /**
      * receive. it's for-us.
      */
     FIB_PATH_TYPE_RECEIVE,
@@ -96,6 +101,7 @@ typedef enum fib_path_type_t_ {
     [FIB_PATH_TYPE_EXCLUSIVE]         = "exclusive",	        \
     [FIB_PATH_TYPE_DEAG]              = "deag",	                \
     [FIB_PATH_TYPE_INTF_RX]           = "intf-rx",	        \
+    [FIB_PATH_TYPE_UDP_ENCAP]         = "udp-encap",	        \
     [FIB_PATH_TYPE_RECEIVE]           = "receive",	        \
 }
 
@@ -285,6 +291,12 @@ typedef struct fib_path_t_ {
 	     */
 	    u32 fp_interface;
 	} intf_rx;
+	struct {
+	    /**
+	     * The UDP Encap object this path resolves through
+	     */
+	    u32 fp_udp_encap_id;
+	} udp_encap;
     };
     STRUCT_MARK(path_hash_end);
 
@@ -479,6 +491,9 @@ format_fib_path (u8 * s, va_list * args)
 		    path->fp_dpo.dpoi_index);
 
 	break;
+    case FIB_PATH_TYPE_UDP_ENCAP:
+        s = format (s, " UDP-encap ID:%d", path->udp_encap.fp_udp_encap_id);
+        break;
     case FIB_PATH_TYPE_RECEIVE:
     case FIB_PATH_TYPE_INTF_RX:
     case FIB_PATH_TYPE_SPECIAL:
@@ -784,6 +799,9 @@ fib_path_unresolve (fib_path_t *path)
             adj_unlock(path->fp_dpo.dpoi_index);
         }
         break;
+    case FIB_PATH_TYPE_UDP_ENCAP:
+	udp_encap_unlock_w_index(path->fp_dpo.dpoi_index);
+        break;
     case FIB_PATH_TYPE_EXCLUSIVE:
 	dpo_reset(&path->exclusive.fp_ex_dpo);
         break;
@@ -989,6 +1007,33 @@ FIXME comment
 	    path->fp_oper_flags |= FIB_PATH_OPER_FLAG_DROP;
 	}
 	break;
+    case FIB_PATH_TYPE_UDP_ENCAP:
+    {
+        dpo_id_t via_dpo = DPO_INVALID;
+
+        /*
+         * hope for the best - clear if restrictions apply.
+         */
+        path->fp_oper_flags |= FIB_PATH_OPER_FLAG_RESOLVED;
+
+        udp_encap_contribute_forwarding(path->udp_encap.fp_udp_encap_id,
+                                        path->fp_nh_proto,
+                                        &via_dpo);
+        /*
+         * If this path is contributing a drop, then it's not resolved
+         */
+        if (dpo_is_drop(&via_dpo) || load_balance_is_drop(&via_dpo))
+        {
+            path->fp_oper_flags &= ~FIB_PATH_OPER_FLAG_RESOLVED;
+        }
+
+        /*
+         * update the path's contributed DPO
+         */
+        dpo_copy(&path->fp_dpo, &via_dpo);
+        dpo_reset(&via_dpo);
+        break;
+    }
     case FIB_PATH_TYPE_INTF_RX:
         ASSERT(0);
     case FIB_PATH_TYPE_DEAG:
@@ -1103,6 +1148,11 @@ fib_path_create (fib_node_index_t pl_index,
         path->receive.fp_interface = rpath->frp_sw_if_index;
         path->receive.fp_addr = rpath->frp_addr;
     }
+    else if (rpath->frp_flags & FIB_ROUTE_PATH_UDP_ENCAP)
+    {
+        path->fp_type = FIB_PATH_TYPE_UDP_ENCAP;
+        path->udp_encap.fp_udp_encap_id = rpath->frp_udp_encap_id;
+    }
     else if (path->fp_cfg_flags & FIB_PATH_CFG_FLAG_INTF_RX)
     {
         path->fp_type = FIB_PATH_TYPE_INTF_RX;
@@ -1346,6 +1396,9 @@ fib_path_cmp_i (const fib_path_t *path1,
 	case FIB_PATH_TYPE_INTF_RX:
 	    res = (path1->intf_rx.fp_interface - path2->intf_rx.fp_interface);
 	    break;
+	case FIB_PATH_TYPE_UDP_ENCAP:
+	    res = (path1->udp_encap.fp_udp_encap_id - path2->udp_encap.fp_udp_encap_id);
+	    break;
 	case FIB_PATH_TYPE_SPECIAL:
 	case FIB_PATH_TYPE_RECEIVE:
 	case FIB_PATH_TYPE_EXCLUSIVE:
@@ -1460,6 +1513,9 @@ fib_path_cmp_w_route_path (fib_node_index_t path_index,
 	case FIB_PATH_TYPE_INTF_RX:
 	    res = (path->intf_rx.fp_interface - rpath->frp_sw_if_index);
             break;
+	case FIB_PATH_TYPE_UDP_ENCAP:
+	    res = (path->udp_encap.fp_udp_encap_id - rpath->frp_udp_encap_id);
+            break;
 	case FIB_PATH_TYPE_DEAG:
 	    res = (path->deag.fp_tbl_id - rpath->frp_fib_index);
 	    if (0 == res)
@@ -1565,6 +1621,7 @@ fib_path_recursive_loop_detect (fib_node_index_t path_index,
     case FIB_PATH_TYPE_DEAG:
     case FIB_PATH_TYPE_RECEIVE:
     case FIB_PATH_TYPE_INTF_RX:
+    case FIB_PATH_TYPE_UDP_ENCAP:
     case FIB_PATH_TYPE_EXCLUSIVE:
 	/*
 	 * these path types cannot be part of a loop, since they are the leaves
@@ -1724,6 +1781,12 @@ fib_path_resolve (fib_node_index_t path_index)
                                 &path->receive.fp_addr,
                                 &path->fp_dpo);
 	break;
+    case FIB_PATH_TYPE_UDP_ENCAP:
+        udp_encap_lock(path->udp_encap.fp_udp_encap_id);
+        udp_encap_contribute_forwarding(path->udp_encap.fp_udp_encap_id,
+                                        path->fp_nh_proto,
+                                        &path->fp_dpo);
+        break;
     case FIB_PATH_TYPE_INTF_RX: {
 	/*
 	 * Resolve via a receive DPO.
@@ -1766,6 +1829,7 @@ fib_path_get_resolving_interface (fib_node_index_t path_index)
         }
         break;
     case FIB_PATH_TYPE_INTF_RX:
+    case FIB_PATH_TYPE_UDP_ENCAP:
     case FIB_PATH_TYPE_SPECIAL:
     case FIB_PATH_TYPE_DEAG:
     case FIB_PATH_TYPE_EXCLUSIVE:
@@ -1872,6 +1936,7 @@ fib_path_contribute_urpf (fib_node_index_t path_index,
     case FIB_PATH_TYPE_DEAG:
     case FIB_PATH_TYPE_RECEIVE:
     case FIB_PATH_TYPE_INTF_RX:
+    case FIB_PATH_TYPE_UDP_ENCAP:
 	/*
 	 * these path types don't link to an adj
 	 */
@@ -1905,12 +1970,13 @@ fib_path_stack_mpls_disp (fib_node_index_t path_index,
                                      &tmp));
         dpo_reset(&tmp);
         break;
-    }                
+    }
     case FIB_PATH_TYPE_RECEIVE:
     case FIB_PATH_TYPE_ATTACHED:
     case FIB_PATH_TYPE_ATTACHED_NEXT_HOP:
     case FIB_PATH_TYPE_RECURSIVE:
     case FIB_PATH_TYPE_INTF_RX:
+    case FIB_PATH_TYPE_UDP_ENCAP:
     case FIB_PATH_TYPE_EXCLUSIVE:
     case FIB_PATH_TYPE_SPECIAL:
         break;
@@ -2072,6 +2138,11 @@ fib_path_contribute_forwarding (fib_node_index_t path_index,
                                          path->attached.fp_interface,
                                          dpo);
             break;
+        case FIB_PATH_TYPE_UDP_ENCAP:
+            udp_encap_contribute_forwarding(path->udp_encap.fp_udp_encap_id,
+                                            path->fp_nh_proto,
+                                            dpo);
+            break;
         case FIB_PATH_TYPE_RECEIVE:
         case FIB_PATH_TYPE_SPECIAL:
             dpo_copy(dpo, &path->fp_dpo);
diff --git a/src/vnet/fib/fib_types.h b/src/vnet/fib/fib_types.h
index 7eadbb9bb70..ec7f1b374dd 100644
--- a/src/vnet/fib/fib_types.h
+++ b/src/vnet/fib/fib_types.h
@@ -307,6 +307,10 @@ typedef enum fib_route_path_flags_t_
      * A deag path using the packet's source not destination address.
      */
     FIB_ROUTE_PATH_SOURCE_LOOKUP = (1 << 8),
+    /**
+     * A path via a UDP encap object.
+     */
+    FIB_ROUTE_PATH_UDP_ENCAP = (1 << 9),
 } fib_route_path_flags_t;
 
 /**
@@ -375,6 +379,10 @@ typedef struct fib_route_path_t_ {
          * The RPF-ID
          */
         fib_rpf_id_t frp_rpf_id;
+        /**
+         * UDP encap ID
+         */
+        u32 frp_udp_encap_id;
     };
     /**
      * The FIB index to lookup the nexthop
diff --git a/src/vnet/ip/ip.api b/src/vnet/ip/ip.api
index df3ae9646c4..85e4b8e04c3 100644
--- a/src/vnet/ip/ip.api
+++ b/src/vnet/ip/ip.api
@@ -368,13 +368,18 @@ autoreply define sw_interface_ip6_set_link_local_address
     @param is_unreach - Drop the packet and rate limit send ICMP unreachable
     @param is_prohibit - Drop the packet and rate limit send ICMP prohibited
     @param is_ipv6 - 0 if an ip4 route, else ip6
-    @param is_local - 
+    @param is_local - The route will result in packets sent to VPP IP stack
+    @param is_udp_encap - The path describes a UDP-o-IP encapsulation.
     @param is_classify - 
     @param is_multipath - Set to 1 if this is a multipath route, else 0
     @param is_source_lookup - The the path is a deaggregate path (i.e. a lookup
     	   		      in another table) is the lookup on the packet's
 			      source address or destination.
-    @param next_hop_weight - 
+    @param next_hop_weight - Weight for Unequal cost multi-path
+    @param next_hop_preference - Path that are up that have the best preference are
+                                 are used for forwarding. lower value is better.
+    @param next_hop_id - Used when the path resolves via an object that has a unique
+                         identifier.
     @param dst_address_length - 
     @param dst_address[16] - 
     @param next_hop_address[16] - 
@@ -390,6 +395,7 @@ autoreply define ip_add_del_route
   u32 table_id;
   u32 classify_table_index;
   u32 next_hop_table_id;
+  u32 next_hop_id;
   u8 create_vrf_if_needed;
   u8 is_add;
   u8 is_drop;
@@ -403,8 +409,10 @@ autoreply define ip_add_del_route
   u8 is_resolve_attached;
   u8 is_l2_bridged;
   u8 is_source_lookup;
+  u8 is_udp_encap;
   u8 next_hop_weight;
   u8 next_hop_preference;
+  u8 next_hop_proto;
   u8 dst_address_length;
   u8 dst_address[16];
   u8 next_hop_address[16];
diff --git a/src/vnet/ip/ip_api.c b/src/vnet/ip/ip_api.c
index fad518f18a5..20e19205756 100644
--- a/src/vnet/ip/ip_api.c
+++ b/src/vnet/ip/ip_api.c
@@ -832,10 +832,12 @@ add_del_route_t_handler (u8 is_multipath,
 			 u8 is_rpf_id,
 			 u8 is_l2_bridged,
 			 u8 is_source_lookup,
+			 u8 is_udp_encap,
 			 u32 fib_index,
 			 const fib_prefix_t * prefix,
 			 dpo_proto_t next_hop_proto,
 			 const ip46_address_t * next_hop,
+			 u32 next_hop_id,
 			 u32 next_hop_sw_if_index,
 			 u8 next_hop_fib_index,
 			 u16 next_hop_weight,
@@ -883,6 +885,11 @@ add_del_route_t_handler (u8 is_multipath,
     path_flags |= FIB_ROUTE_PATH_SOURCE_LOOKUP;
   if (is_multicast)
     entry_flags |= FIB_ENTRY_FLAG_MULTICAST;
+  if (is_udp_encap)
+    {
+      path_flags |= FIB_ROUTE_PATH_UDP_ENCAP;
+      path.frp_udp_encap_id = next_hop_id;
+    }
 
   path.frp_flags = path_flags;
 
@@ -1112,8 +1119,10 @@ ip4_add_del_route_t_handler (vl_api_ip_add_del_route_t * mp)
 				   mp->is_resolve_attached, 0, 0,
 				   mp->is_l2_bridged,
 				   mp->is_source_lookup,
+				   mp->is_udp_encap,
 				   fib_index, &pfx, DPO_PROTO_IP4,
 				   &nh,
+				   ntohl (mp->next_hop_id),
 				   ntohl (mp->next_hop_sw_if_index),
 				   next_hop_fib_index,
 				   mp->next_hop_weight,
@@ -1173,8 +1182,10 @@ ip6_add_del_route_t_handler (vl_api_ip_add_del_route_t * mp)
 				   mp->is_resolve_attached, 0, 0,
 				   mp->is_l2_bridged,
 				   mp->is_source_lookup,
+				   mp->is_udp_encap,
 				   fib_index, &pfx, DPO_PROTO_IP6,
-				   &nh, ntohl (mp->next_hop_sw_if_index),
+				   &nh, ntohl (mp->next_hop_id),
+				   ntohl (mp->next_hop_sw_if_index),
 				   next_hop_fib_index,
 				   mp->next_hop_weight,
 				   mp->next_hop_preference,
diff --git a/src/vnet/ip/lookup.c b/src/vnet/ip/lookup.c
index 3d5dc36c9a0..a376e51d789 100644
--- a/src/vnet/ip/lookup.c
+++ b/src/vnet/ip/lookup.c
@@ -368,11 +368,11 @@ vnet_ip_route_cmd (vlib_main_t * vm,
   unformat_input_t _line_input, *line_input = &_line_input;
   fib_route_path_t *rpaths = NULL, rpath;
   dpo_id_t dpo = DPO_INVALID, *dpos = NULL;
+  u32 table_id, is_del, udp_encap_id;
   fib_prefix_t *prefixs = NULL, pfx;
   mpls_label_t out_label, via_label;
   clib_error_t *error = NULL;
   u32 weight, preference;
-  u32 table_id, is_del;
   vnet_main_t *vnm;
   u32 fib_index;
   f64 count;
@@ -527,6 +527,13 @@ vnet_ip_route_cmd (vlib_main_t * vm,
 	  rpath.frp_proto = DPO_PROTO_IP6;
 	  vec_add1 (rpaths, rpath);
 	}
+      else if (unformat (line_input, "via udp-encap %d", &udp_encap_id))
+	{
+	  rpath.frp_udp_encap_id = udp_encap_id;
+	  rpath.frp_flags |= FIB_ROUTE_PATH_UDP_ENCAP;
+	  rpath.frp_proto = fib_proto_to_dpo (pfx.fp_proto);
+	  vec_add1 (rpaths, rpath);
+	}
       else if (unformat (line_input,
 			 "lookup in table %d", &rpath.frp_fib_index))
 	{
diff --git a/src/vnet/mpls/mpls_api.c b/src/vnet/mpls/mpls_api.c
index c47e94dd34a..a55daa2b0c4 100644
--- a/src/vnet/mpls/mpls_api.c
+++ b/src/vnet/mpls/mpls_api.c
@@ -234,9 +234,11 @@ mpls_route_add_del_t_handler (vnet_main_t * vnm,
                                    mp->mr_is_rpf_id,
                                    0,	// l2_bridged
                                    0,   // is source_lookup
+                                   0,   // is_udp_encap
 				   fib_index, &pfx,
 				   mp->mr_next_hop_proto,
-				   &nh, ntohl (mp->mr_next_hop_sw_if_index),
+				   &nh, ~0, // next_hop_id
+                                   ntohl (mp->mr_next_hop_sw_if_index),
 				   next_hop_fib_index,
 				   mp->mr_next_hop_weight,
 				   mp->mr_next_hop_preference,
diff --git a/src/vnet/udp/udp.api b/src/vnet/udp/udp.api
new file mode 100644
index 00000000000..25ee96489a2
--- /dev/null
+++ b/src/vnet/udp/udp.api
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2016 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.
+ */
+
+/** \file
+
+    This file defines vpp UDP control-plane API messages which are generally
+    called through a shared memory interface. 
+*/
+
+vl_api_version 1.0.0
+
+/** \brief Add / del table request
+           A table can be added multiple times, but need be deleted only once.
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param is_ipv6 - V4 or V6 table
+    @param table_id - table ID associated with the encap destination
+*/
+autoreply define udp_encap_add_del
+{
+  u32 client_index;
+  u32 context;
+  u32 id;
+  u32 table_id;
+  u8 is_ip6;
+  u8 is_add;
+  u16 src_port;
+  u16 dst_port;
+  u8 src_ip[16];
+  u8 dst_ip[16];
+};
+
+define udp_encap_dump
+{
+  u32 client_index;
+  u32 context;
+};
+
+define udp_encap_details
+{
+  u32 context;
+  u32 id;
+  u32 table_id;
+  u8 is_ip6;
+  u16 src_port;
+  u16 dst_port;
+  u8 src_ip[16];
+  u8 dst_ip[16];
+};
+
+/*
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/udp/udp_api.c b/src/vnet/udp/udp_api.c
new file mode 100644
index 00000000000..e65235a5396
--- /dev/null
+++ b/src/vnet/udp/udp_api.c
@@ -0,0 +1,193 @@
+/*
+ * Copyright (c) 2017 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 <vnet/vnet.h>
+#include <vlibmemory/api.h>
+
+#include <vnet/udp/udp_encap.h>
+#include <vnet/fib/fib_table.h>
+
+#include <vnet/vnet_msg_enum.h>
+
+#define vl_typedefs		/* define message structures */
+#include <vnet/vnet_all_api_h.h>
+#undef vl_typedefs
+
+#define vl_endianfun		/* define message structures */
+#include <vnet/vnet_all_api_h.h>
+#undef vl_endianfun
+
+/* instantiate all the print functions we know about */
+#define vl_print(handle, ...) vlib_cli_output (handle, __VA_ARGS__)
+#define vl_printfun
+#include <vnet/vnet_all_api_h.h>
+#undef vl_printfun
+
+#include <vlibapi/api_helper_macros.h>
+
+
+#define foreach_udp_api_msg                      \
+  _(UDP_ENCAP_ADD_DEL, udp_encap_add_del)        \
+_(UDP_ENCAP_DUMP, udp_encap_dump)
+
+static void
+send_udp_encap_details (const udp_encap_t * ue,
+			unix_shared_memory_queue_t * q, u32 context)
+{
+  vl_api_udp_encap_details_t *mp;
+  fib_table_t *fib_table;
+
+  mp = vl_msg_api_alloc (sizeof (*mp));
+  memset (mp, 0, sizeof (*mp));
+  mp->_vl_msg_id = ntohs (VL_API_UDP_ENCAP_DETAILS);
+  mp->context = context;
+
+  mp->is_ip6 = (ue->ue_ip_proto == FIB_PROTOCOL_IP6);
+
+  if (FIB_PROTOCOL_IP4 == ue->ue_ip_proto)
+    {
+      clib_memcpy (mp->src_ip, &ue->ue_hdrs.ip4.ue_ip4.src_address, 4);
+      clib_memcpy (mp->dst_ip, &ue->ue_hdrs.ip4.ue_ip4.dst_address, 4);
+      mp->src_port = htons (ue->ue_hdrs.ip4.ue_udp.src_port);
+      mp->dst_port = htons (ue->ue_hdrs.ip4.ue_udp.dst_port);
+    }
+  else
+    {
+      clib_memcpy (mp->src_ip, &ue->ue_hdrs.ip6.ue_ip6.src_address, 16);
+      clib_memcpy (mp->dst_ip, &ue->ue_hdrs.ip6.ue_ip6.dst_address, 16);
+      mp->src_port = htons (ue->ue_hdrs.ip6.ue_udp.src_port);
+      mp->dst_port = htons (ue->ue_hdrs.ip6.ue_udp.dst_port);
+    }
+
+  fib_table = fib_table_get (ue->ue_fib_index, ue->ue_ip_proto);
+  mp->table_id = htonl (fib_table->ft_table_id);
+  mp->id = htonl (ue->ue_id);
+
+  vl_msg_api_send_shmem (q, (u8 *) & mp);
+}
+
+static void
+vl_api_udp_encap_dump_t_handler (vl_api_udp_encap_dump_t * mp,
+				 vlib_main_t * vm)
+{
+  unix_shared_memory_queue_t *q;
+  udp_encap_t *ue;
+
+  q = vl_api_client_index_to_input_queue (mp->client_index);
+  if (q == 0)
+    return;
+
+  /* *INDENT-OFF* */
+  pool_foreach(ue, udp_encap_pool,
+  ({
+    send_udp_encap_details(ue, q, mp->context);
+  }));
+  /* *INDENT-OFF* */
+}
+
+static void
+vl_api_udp_encap_add_del_t_handler (vl_api_udp_encap_add_del_t * mp,
+                                    vlib_main_t * vm)
+{
+  vl_api_udp_encap_add_del_reply_t *rmp;
+  ip46_address_t src_ip, dst_ip;
+  u32 fib_index, table_id, ue_id;
+  fib_protocol_t fproto;
+  int rv = 0;
+
+  ue_id = ntohl(mp->id);
+  table_id = ntohl(mp->table_id);
+  fproto = (mp->is_ip6 ? FIB_PROTOCOL_IP6 : FIB_PROTOCOL_IP4);
+
+  fib_index = fib_table_find(fproto, table_id);
+
+  if (~0 == fib_index)
+    {
+      rv = VNET_API_ERROR_NO_SUCH_TABLE;
+      goto done;
+    }
+
+  if (FIB_PROTOCOL_IP4 == fproto)
+    {
+      clib_memcpy(&src_ip.ip4, mp->src_ip, 4);
+      clib_memcpy(&dst_ip.ip4, mp->dst_ip, 4);
+    }
+  else
+    {
+      clib_memcpy(&src_ip.ip6, mp->src_ip, 16);
+      clib_memcpy(&dst_ip.ip6, mp->dst_ip, 16);
+    }
+
+  if (mp->is_add)
+    {
+      udp_encap_add_and_lock(ue_id, fproto, fib_index,
+                             &src_ip, &dst_ip,
+                             ntohs(mp->src_port),
+                             ntohs(mp->dst_port),
+                             UDP_ENCAP_FIXUP_NONE);
+    }
+  else
+    {
+      udp_encap_unlock(ue_id);
+    }
+
+ done:
+  REPLY_MACRO (VL_API_UDP_ENCAP_ADD_DEL_REPLY);
+}
+
+#define vl_msg_name_crc_list
+#include <vnet/udp/udp.api.h>
+#undef vl_msg_name_crc_list
+
+static void
+setup_message_id_table (api_main_t * am)
+{
+#define _(id,n,crc) vl_msg_api_add_msg_name_crc (am, #n "_" #crc, id);
+  foreach_vl_msg_name_crc_udp;
+#undef _
+}
+
+static clib_error_t *
+udp_api_hookup (vlib_main_t * vm)
+{
+  api_main_t *am = &api_main;
+
+#define _(N,n)                                                  \
+    vl_msg_api_set_handlers(VL_API_##N, #n,                     \
+                           vl_api_##n##_t_handler,              \
+                           vl_noop_handler,                     \
+                           vl_api_##n##_t_endian,               \
+                           vl_api_##n##_t_print,                \
+                           sizeof(vl_api_##n##_t), 1);
+  foreach_udp_api_msg;
+#undef _
+
+  /*
+   * Set up the (msg_name, crc, message-id) table
+   */
+  setup_message_id_table (am);
+
+  return 0;
+}
+
+VLIB_API_INIT_FUNCTION (udp_api_hookup);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/udp/udp_encap.c b/src/vnet/udp/udp_encap.c
new file mode 100644
index 00000000000..98b824ba866
--- /dev/null
+++ b/src/vnet/udp/udp_encap.c
@@ -0,0 +1,617 @@
+/*
+ * Copyright (c) 2017 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 <vnet/udp/udp_encap.h>
+#include <vnet/fib/fib_entry.h>
+#include <vnet/fib/fib_table.h>
+#include <vnet/dpo/drop_dpo.h>
+
+/**
+ * Registered DPO types for the IP header encapsulated, v4 or v6.
+ */
+dpo_type_t udp_encap_dpo_types[FIB_PROTOCOL_MAX];
+
+/**
+ * Hash DB to map from client ID to VPP index.
+ */
+uword *udp_encap_db;
+
+/**
+ * Pool of encaps
+ */
+udp_encap_t *udp_encap_pool;
+
+static udp_encap_t *
+udp_encap_get_w_id (u32 id)
+{
+  udp_encap_t *ue = NULL;
+  index_t uei;
+
+  uei = udp_encap_find (id);
+
+  if (INDEX_INVALID != uei)
+    {
+      ue = udp_encap_get (uei);
+    }
+
+  return (ue);
+}
+
+static void
+udp_encap_restack (udp_encap_t * ue)
+{
+  dpo_stack (udp_encap_dpo_types[ue->ue_ip_proto],
+	     fib_proto_to_dpo (ue->ue_ip_proto),
+	     &ue->ue_dpo,
+	     fib_entry_contribute_ip_forwarding (ue->ue_fib_entry_index));
+}
+
+index_t
+udp_encap_add_and_lock (u32 id,
+			fib_protocol_t proto,
+			index_t fib_index,
+			const ip46_address_t * src_ip,
+			const ip46_address_t * dst_ip,
+			u16 src_port,
+			u16 dst_port, udp_encap_fixup_flags_t flags)
+{
+  udp_encap_t *ue;
+  index_t uei;
+
+  uei = udp_encap_find (id);
+
+  if (INDEX_INVALID == uei)
+    {
+      u8 pfx_len = 0;
+
+      pool_get (udp_encap_pool, ue);
+      uei = ue - udp_encap_pool;
+
+      hash_set (udp_encap_db, id, uei);
+
+      fib_node_init (&ue->ue_fib_node, FIB_NODE_TYPE_UDP_ENCAP);
+      fib_node_lock (&ue->ue_fib_node);
+      ue->ue_fib_index = fib_index;
+      ue->ue_flags = flags;
+      ue->ue_id = id;
+      ue->ue_ip_proto = proto;
+
+      switch (proto)
+	{
+	case FIB_PROTOCOL_IP4:
+	  pfx_len = 32;
+	  ue->ue_hdrs.ip4.ue_ip4.ip_version_and_header_length = 0x45;
+	  ue->ue_hdrs.ip4.ue_ip4.ttl = 254;
+	  ue->ue_hdrs.ip4.ue_ip4.protocol = IP_PROTOCOL_UDP;
+	  ue->ue_hdrs.ip4.ue_ip4.src_address.as_u32 = src_ip->ip4.as_u32;
+	  ue->ue_hdrs.ip4.ue_ip4.dst_address.as_u32 = dst_ip->ip4.as_u32;
+	  ue->ue_hdrs.ip4.ue_ip4.checksum =
+	    ip4_header_checksum (&ue->ue_hdrs.ip4.ue_ip4);
+	  ue->ue_hdrs.ip4.ue_udp.src_port = clib_host_to_net_u16 (src_port);
+	  ue->ue_hdrs.ip4.ue_udp.dst_port = clib_host_to_net_u16 (dst_port);
+
+	  break;
+	case FIB_PROTOCOL_IP6:
+	  pfx_len = 128;
+	  ue->ue_hdrs.ip6.ue_ip6.ip_version_traffic_class_and_flow_label =
+	    clib_host_to_net_u32 (6 << 28);
+	  ue->ue_hdrs.ip6.ue_ip6.hop_limit = 255;
+	  ue->ue_hdrs.ip6.ue_ip6.protocol = IP_PROTOCOL_UDP;
+	  ue->ue_hdrs.ip6.ue_ip6.src_address.as_u64[0] =
+	    src_ip->ip6.as_u64[0];
+	  ue->ue_hdrs.ip6.ue_ip6.src_address.as_u64[1] =
+	    src_ip->ip6.as_u64[1];
+	  ue->ue_hdrs.ip6.ue_ip6.dst_address.as_u64[0] =
+	    dst_ip->ip6.as_u64[0];
+	  ue->ue_hdrs.ip6.ue_ip6.dst_address.as_u64[1] =
+	    dst_ip->ip6.as_u64[1];
+	  ue->ue_hdrs.ip6.ue_udp.src_port = clib_host_to_net_u16 (src_port);
+	  ue->ue_hdrs.ip6.ue_udp.dst_port = clib_host_to_net_u16 (dst_port);
+
+	  break;
+	default:
+	  ASSERT (0);
+	}
+
+      /*
+       * track the destination address
+       */
+      fib_prefix_t dst_pfx = {
+	.fp_proto = proto,
+	.fp_len = pfx_len,
+	.fp_addr = *dst_ip,
+      };
+
+      ue->ue_fib_entry_index =
+	fib_table_entry_special_add (fib_index,
+				     &dst_pfx,
+				     FIB_SOURCE_RR, FIB_ENTRY_FLAG_NONE);
+      ue->ue_fib_sibling =
+	fib_entry_child_add (ue->ue_fib_entry_index,
+			     FIB_NODE_TYPE_UDP_ENCAP, uei);
+
+      udp_encap_restack (ue);
+    }
+  else
+    {
+      /*
+       * existing entry. updates not supported yet
+       */
+      uei = INDEX_INVALID;
+    }
+  return (uei);
+}
+
+void
+udp_encap_contribute_forwarding (u32 id, dpo_proto_t proto, dpo_id_t * dpo)
+{
+  index_t uei;
+
+  uei = udp_encap_find (id);
+
+  if (INDEX_INVALID == uei)
+    {
+      dpo_copy (dpo, drop_dpo_get (proto));
+    }
+  else
+    {
+      udp_encap_t *ue;
+
+      ue = udp_encap_get (uei);
+
+      dpo_set (dpo, udp_encap_dpo_types[ue->ue_ip_proto], proto, uei);
+    }
+}
+
+index_t
+udp_encap_find (u32 id)
+{
+  uword *p;
+
+  p = hash_get (udp_encap_db, id);
+
+  if (NULL != p)
+    return p[0];
+
+  return INDEX_INVALID;
+}
+
+void
+udp_encap_lock (u32 id)
+{
+  udp_encap_t *ue;
+
+  ue = udp_encap_get_w_id (id);
+
+  if (NULL != ue)
+    {
+      fib_node_lock (&ue->ue_fib_node);
+    }
+}
+
+void
+udp_encap_unlock_w_index (index_t uei)
+{
+  udp_encap_t *ue;
+
+  if (INDEX_INVALID == uei)
+    {
+      return;
+    }
+
+  ue = udp_encap_get (uei);
+
+  if (NULL != ue)
+    {
+      fib_node_unlock (&ue->ue_fib_node);
+    }
+}
+
+void
+udp_encap_unlock (u32 id)
+{
+  udp_encap_t *ue;
+
+  ue = udp_encap_get_w_id (id);
+
+  if (NULL != ue)
+    {
+      fib_node_unlock (&ue->ue_fib_node);
+    }
+}
+
+static void
+udp_encap_dpo_lock (dpo_id_t * dpo)
+{
+  udp_encap_t *ue;
+
+  ue = udp_encap_get (dpo->dpoi_index);
+
+  fib_node_lock (&ue->ue_fib_node);
+}
+
+static void
+udp_encap_dpo_unlock (dpo_id_t * dpo)
+{
+  udp_encap_t *ue;
+
+  ue = udp_encap_get (dpo->dpoi_index);
+
+  fib_node_unlock (&ue->ue_fib_node);
+}
+
+static u8 *
+format_udp_encap_i (u8 * s, va_list * args)
+{
+  index_t uei = va_arg (*args, index_t);
+  u32 indent = va_arg (*args, u32);
+  u32 details = va_arg (*args, u32);
+  udp_encap_t *ue;
+
+  ue = udp_encap_get (uei);
+
+  // FIXME
+  s = format (s, "udp-ecap:[%d]: id:%d ip-fib-index:%d",
+	      uei, ue->ue_id, ue->ue_fib_index);
+  if (FIB_PROTOCOL_IP4 == ue->ue_ip_proto)
+    {
+      s = format (s, "ip:[src:%U, dst:%U] udp:[src:%d, dst:%d]",
+		  format_ip4_address,
+		  &ue->ue_hdrs.ip4.ue_ip4.src_address,
+		  format_ip4_address,
+		  &ue->ue_hdrs.ip4.ue_ip4.dst_address,
+		  clib_net_to_host_u16 (ue->ue_hdrs.ip4.ue_udp.src_port),
+		  clib_net_to_host_u16 (ue->ue_hdrs.ip4.ue_udp.dst_port));
+    }
+  else
+    {
+      s = format (s, "ip:[src:%U, dst:%U] udp:[src:%d dst:%d]",
+		  format_ip6_address,
+		  &ue->ue_hdrs.ip6.ue_ip6.src_address,
+		  format_ip6_address,
+		  &ue->ue_hdrs.ip6.ue_ip6.dst_address,
+		  clib_net_to_host_u16 (ue->ue_hdrs.ip6.ue_udp.src_port),
+		  clib_net_to_host_u16 (ue->ue_hdrs.ip6.ue_udp.dst_port));
+    }
+  if (details)
+    {
+      s = format (s, " locks:%d", ue->ue_fib_node.fn_locks);
+      s = format (s, "\n%UStacked on:", format_white_space, indent + 1);
+      s = format (s, "\n%U%U",
+		  format_white_space, indent + 2,
+		  format_dpo_id, &ue->ue_dpo, indent + 3);
+    }
+  return (s);
+}
+
+static u8 *
+format_udp_encap_dpo (u8 * s, va_list * args)
+{
+  index_t uei = va_arg (*args, index_t);
+  u32 indent = va_arg (*args, u32);
+
+  return (format (s, "%U", format_udp_encap_i, uei, indent, 1));
+}
+
+u8 *
+format_udp_encap (u8 * s, va_list * args)
+{
+  u32 id = va_arg (*args, u32);
+  u32 details = va_arg (*args, u32);
+  index_t uei;
+
+  uei = udp_encap_find (id);
+
+  if (INDEX_INVALID == uei)
+    {
+      return (format (s, "Invalid udp-encap ID: %d", id));
+    }
+
+  return (format (s, "%U", format_udp_encap_i, uei, 0, details));
+}
+
+static udp_encap_t *
+udp_encap_from_fib_node (fib_node_t * node)
+{
+#if (CLIB_DEBUG > 0)
+  ASSERT (FIB_NODE_TYPE_UDP_ENCAP == node->fn_type);
+#endif
+  return ((udp_encap_t *) (((char *) node) -
+			   STRUCT_OFFSET_OF (udp_encap_t, ue_fib_node)));
+}
+
+/**
+ * Function definition to backwalk a FIB node
+ */
+static fib_node_back_walk_rc_t
+udp_encap_fib_back_walk (fib_node_t * node, fib_node_back_walk_ctx_t * ctx)
+{
+  udp_encap_restack (udp_encap_from_fib_node (node));
+
+  return (FIB_NODE_BACK_WALK_CONTINUE);
+}
+
+/**
+ * Function definition to get a FIB node from its index
+ */
+static fib_node_t *
+udp_encap_fib_node_get (fib_node_index_t index)
+{
+  udp_encap_t *ue;
+
+  ue = pool_elt_at_index (udp_encap_pool, index);
+
+  return (&ue->ue_fib_node);
+}
+
+/**
+ * Function definition to inform the FIB node that its last lock has gone.
+ */
+static void
+udp_encap_fib_last_lock_gone (fib_node_t * node)
+{
+  udp_encap_t *ue;
+
+  ue = udp_encap_from_fib_node (node);
+
+    /**
+     * reset the stacked DPO to unlock it
+     */
+  dpo_reset (&ue->ue_dpo);
+  hash_unset (udp_encap_db, ue->ue_id);
+
+  fib_entry_child_remove (ue->ue_fib_entry_index, ue->ue_fib_sibling);
+  fib_table_entry_delete_index (ue->ue_fib_entry_index, FIB_SOURCE_RR);
+
+
+  pool_put (udp_encap_pool, ue);
+}
+
+const static char *const udp4_encap_ip4_nodes[] = {
+  "udp4-encap",
+  NULL,
+};
+
+const static char *const udp4_encap_ip6_nodes[] = {
+  "udp4-encap",
+  NULL,
+};
+
+const static char *const udp4_encap_mpls_nodes[] = {
+  "udp4-encap",
+  NULL,
+};
+
+const static char *const udp6_encap_ip4_nodes[] = {
+  "udp6-encap",
+  NULL,
+};
+
+const static char *const udp6_encap_ip6_nodes[] = {
+  "udp6-encap",
+  NULL,
+};
+
+const static char *const udp6_encap_mpls_nodes[] = {
+  "udp6-encap",
+  NULL,
+};
+
+const static char *const *const udp4_encap_nodes[DPO_PROTO_NUM] = {
+  [DPO_PROTO_IP4] = udp4_encap_ip4_nodes,
+  [DPO_PROTO_IP6] = udp4_encap_ip6_nodes,
+  [DPO_PROTO_MPLS] = udp4_encap_mpls_nodes,
+};
+
+const static char *const *const udp6_encap_nodes[DPO_PROTO_NUM] = {
+  [DPO_PROTO_IP4] = udp6_encap_ip4_nodes,
+  [DPO_PROTO_IP6] = udp6_encap_ip6_nodes,
+  [DPO_PROTO_MPLS] = udp6_encap_mpls_nodes,
+};
+
+/*
+ * Virtual function table registered by UDP encaps
+ * for participation in the FIB object graph.
+ */
+const static fib_node_vft_t udp_encap_fib_vft = {
+  .fnv_get = udp_encap_fib_node_get,
+  .fnv_last_lock = udp_encap_fib_last_lock_gone,
+  .fnv_back_walk = udp_encap_fib_back_walk,
+};
+
+const static dpo_vft_t udp_encap_dpo_vft = {
+  .dv_lock = udp_encap_dpo_lock,
+  .dv_unlock = udp_encap_dpo_unlock,
+  .dv_format = format_udp_encap_dpo,
+  //.dv_mem_show = replicate_mem_show,
+};
+
+clib_error_t *
+udp_encap_init (vlib_main_t * vm)
+{
+  udp_encap_db = hash_create (0, sizeof (index_t));
+
+  fib_node_register_type (FIB_NODE_TYPE_UDP_ENCAP, &udp_encap_fib_vft);
+
+  udp_encap_dpo_types[FIB_PROTOCOL_IP4] =
+    dpo_register_new_type (&udp_encap_dpo_vft, udp4_encap_nodes);
+  udp_encap_dpo_types[FIB_PROTOCOL_IP6] =
+    dpo_register_new_type (&udp_encap_dpo_vft, udp6_encap_nodes);
+
+  return (NULL);
+}
+
+VLIB_INIT_FUNCTION (udp_encap_init);
+
+clib_error_t *
+udp_encap_cli (vlib_main_t * vm,
+	       unformat_input_t * main_input, vlib_cli_command_t * cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+  clib_error_t *error = NULL;
+  ip46_address_t src_ip, dst_ip;
+  u32 table_id, ue_id;
+  u32 src_port, dst_port;
+  udp_encap_fixup_flags_t flags;
+  fib_protocol_t fproto;
+  u8 is_del;
+
+  is_del = 0;
+  table_id = 0;
+  flags = UDP_ENCAP_FIXUP_NONE;
+  fproto = FIB_PROTOCOL_MAX;
+  dst_port = 0;
+  ue_id = ~0;
+
+  /* Get a line of input. */
+  if (!unformat_user (main_input, unformat_line_input, line_input))
+    return 0;
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "id %d", &ue_id))
+	;
+      else if (unformat (line_input, "add"))
+	is_del = 0;
+      else if (unformat (line_input, "del"))
+	is_del = 1;
+      else if (unformat (line_input, "%U %U",
+			 unformat_ip4_address,
+			 &src_ip.ip4, unformat_ip4_address, &dst_ip.ip4))
+	fproto = FIB_PROTOCOL_IP4;
+      else if (unformat (line_input, "%U %U",
+			 unformat_ip6_address,
+			 &src_ip.ip6, unformat_ip6_address, &dst_ip.ip6))
+	fproto = FIB_PROTOCOL_IP6;
+      else if (unformat (line_input, "%d %d", &src_port, &dst_port))
+	;
+      else if (unformat (line_input, "%d", &dst_port))
+	;
+      else if (unformat (line_input, "table-id %d", &table_id))
+	;
+      else if (unformat (line_input, "src-port-is-entropy"))
+	flags |= UDP_ENCAP_FIXUP_UDP_SRC_PORT_ENTROPY;
+      else
+	{
+	  error = unformat_parse_error (line_input);
+	  goto done;
+	}
+    }
+
+  if (~0 == ue_id)
+    {
+      error =
+	clib_error_return (0, "An ID for the UDP encap instance is required");
+      goto done;
+    }
+
+  if (!is_del && fproto != FIB_PROTOCOL_MAX)
+    {
+      u32 fib_index;
+      index_t uei;
+
+      fib_index = fib_table_find (fproto, table_id);
+
+      if (~0 == fib_index)
+	{
+	  error = clib_error_return (0, "Nonexistent table id %d", table_id);
+	  goto done;
+	}
+
+      uei = udp_encap_add_and_lock (ue_id, fproto, fib_index,
+				    &src_ip, &dst_ip,
+				    src_port, dst_port, flags);
+
+      if (INDEX_INVALID == uei)
+	{
+	  error =
+	    clib_error_return (0, "update to existing encap not supported %d",
+			       ue_id);
+	  goto done;
+	}
+    }
+  else if (is_del)
+    {
+      udp_encap_unlock (ue_id);
+    }
+  else
+    {
+      error =
+	clib_error_return (0,
+			   "Some IP addresses would be usefull, don't you think?",
+			   ue_id);
+    }
+
+done:
+  unformat_free (line_input);
+  return error;
+}
+
+clib_error_t *
+udp_encap_show (vlib_main_t * vm,
+		unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  u32 ue_id;
+
+  ue_id = ~0;
+
+  /* Get a line of input. */
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "%d", &ue_id))
+	;
+    }
+
+  if (~0 == ue_id)
+    {
+      udp_encap_t *ue;
+
+      /* *INDENT-OFF* */
+      pool_foreach(ue, udp_encap_pool,
+      ({
+        vlib_cli_output(vm, "%U", format_udp_encap, ue->ue_id, 0);
+      }));
+      /* *INDENT-ON* */
+    }
+  else
+    {
+      vlib_cli_output (vm, "%U", format_udp_encap, ue_id, 1);
+    }
+
+  return NULL;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (udp_encap_add_command, static) = {
+  .path = "udp encap",
+  .short_help = "udp encap [add|del] <id ID> <src-ip> <dst-ip> [<src-port>] <dst-port>  [src-port-is-entropy] [table-id <table>]",
+  .function = udp_encap_cli,
+  .is_mp_safe = 1,
+};
+VLIB_CLI_COMMAND (udp_encap_show_command, static) = {
+  .path = "show udp encap",
+  .short_help = "show udp encap [ID]",
+  .function = udp_encap_show,
+  .is_mp_safe = 1,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/udp/udp_encap.h b/src/vnet/udp/udp_encap.h
new file mode 100644
index 00000000000..b8f329dcbee
--- /dev/null
+++ b/src/vnet/udp/udp_encap.h
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2016 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.
+ */
+
+#ifndef __UDP_ENCAP_H__
+#define __UDP_ENCAP_H__
+
+#include <vnet/ip/ip.h>
+#include <vnet/udp/udp.h>
+#include <vnet/fib/fib_node.h>
+
+/**
+ * UDP encapsualtion.
+ * A representation of the encapsulation of packets in UDP-over-IP.
+ * This is encapsulation only, there is no tunnel interface, hence
+ * it is uni-directional. For decap register a handler with the UDP port
+ * dispatcher.
+ */
+
+/**
+ * Fixup behaviour. Actions performed on the encap in the data-plance
+ */
+typedef enum udp_encap_fixup_flags_t_
+{
+  UDP_ENCAP_FIXUP_NONE = 0,
+    /**
+     * UDP source port contains an entropy/hash value for load-balancing by downstream peers.
+     */
+  UDP_ENCAP_FIXUP_UDP_SRC_PORT_ENTROPY = (1 << 0),
+} udp_encap_fixup_flags_t;
+
+/**
+ * The UDP encap represenation
+ */
+typedef struct udp_encap_t_
+{
+    /**
+     * The first cacheline contains the data used in the data-plane
+     */
+  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
+
+    /**
+     * The headers to paint, in packet painting order
+     */
+  union
+  {
+    struct
+    {
+      ip4_header_t ue_ip4;
+      udp_header_t ue_udp;
+    } __attribute__ ((packed)) ip4;
+    struct
+    {
+      ip6_header_t ue_ip6;
+      udp_header_t ue_udp;
+    } __attribute__ ((packed)) ip6;
+  } __attribute__ ((packed)) ue_hdrs;
+
+    /**
+     * Flags controlling fixup behaviour
+     */
+  udp_encap_fixup_flags_t ue_flags;
+
+    /**
+     * The DPO used to forward to the next node in the VLIB graph
+     */
+  dpo_id_t ue_dpo;
+
+    /**
+     * the protocol of the IP header imposed
+     */
+  fib_protocol_t ue_ip_proto;
+
+    CLIB_CACHE_LINE_ALIGN_MARK (cacheline1);
+
+    /**
+     * linkage into the FIB graph
+     */
+  fib_node_t ue_fib_node;
+
+    /**
+     * The ID given by the user/client.
+     * This ID is used by the client for modifications.
+     */
+  u32 ue_id;
+
+    /**
+     * Tracking information for the IP destination
+     */
+  fib_node_index_t ue_fib_entry_index;
+  u32 ue_fib_sibling;
+
+    /**
+     * The FIB index in which the encap destination resides
+     */
+  index_t ue_fib_index;
+} udp_encap_t;
+
+extern index_t udp_encap_add_and_lock (u32 id,
+				       fib_protocol_t proto,
+				       index_t fib_index,
+				       const ip46_address_t * src_ip,
+				       const ip46_address_t * dst_ip,
+				       u16 src_port,
+				       u16 dst_port,
+				       udp_encap_fixup_flags_t flags);
+
+extern index_t udp_encap_find (u32 id);
+extern void udp_encap_lock (u32 id);
+extern void udp_encap_unlock (u32 id);
+extern u8 *format_udp_encap (u8 * s, va_list * args);
+extern void udp_encap_unlock_w_index (index_t uei);
+extern void udp_encap_contribute_forwarding (u32 id,
+					     dpo_proto_t proto,
+					     dpo_id_t * dpo);
+
+/**
+ * Pool of encaps
+ */
+extern udp_encap_t *udp_encap_pool;
+
+static inline udp_encap_t *
+udp_encap_get (index_t uei)
+{
+  return (pool_elt_at_index (udp_encap_pool, uei));
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
+
+#endif
diff --git a/src/vnet/udp/udp_encap_node.c b/src/vnet/udp/udp_encap_node.c
new file mode 100644
index 00000000000..09a76b530f6
--- /dev/null
+++ b/src/vnet/udp/udp_encap_node.c
@@ -0,0 +1,280 @@
+/*
+ * Copyright (c) 2017 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 <vnet/udp/udp_encap.h>
+
+typedef struct udp4_encap_trace_t_
+{
+  udp_header_t udp;
+  ip4_header_t ip;
+} udp4_encap_trace_t;
+
+typedef struct udp6_encap_trace_t_
+{
+  udp_header_t udp;
+  ip6_header_t ip;
+} udp6_encap_trace_t;
+
+static u8 *
+format_udp4_encap_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 *);
+  udp4_encap_trace_t *t;
+
+  t = va_arg (*args, udp4_encap_trace_t *);
+
+  s = format (s, "%U\n  %U",
+	      format_ip4_header, &t->ip, sizeof (t->ip),
+	      format_udp_header, &t->udp, sizeof (t->udp));
+  return (s);
+}
+
+static u8 *
+format_udp6_encap_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 *);
+  udp6_encap_trace_t *t;
+
+  t = va_arg (*args, udp6_encap_trace_t *);
+
+  s = format (s, "%U\n  %U",
+	      format_ip6_header, &t->ip, sizeof (t->ip),
+	      format_udp_header, &t->udp, sizeof (t->udp));
+  return (s);
+}
+
+always_inline uword
+udp_encap_inline (vlib_main_t * vm,
+		  vlib_node_runtime_t * node,
+		  vlib_frame_t * frame, int is_encap_v6)
+{
+  u32 *from = vlib_frame_vector_args (frame);
+  u32 n_left_from, n_left_to_next, *to_next, next_index;
+
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  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;
+	  udp_encap_t *ue0, *ue1;
+	  u32 bi0, next0, uei0;
+	  u32 bi1, next1, uei1;
+
+	  /* 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);
+	  }
+
+	  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);
+
+	  uei0 = vnet_buffer (b0)->ip.adj_index[VLIB_TX];
+	  uei1 = vnet_buffer (b1)->ip.adj_index[VLIB_TX];
+
+	  /* Rewrite packet header and updates lengths. */
+	  ue0 = udp_encap_get (uei0);
+	  ue1 = udp_encap_get (uei1);
+
+	  /* Paint */
+	  if (is_encap_v6)
+	    {
+	      const u8 n_bytes =
+		sizeof (udp_header_t) + sizeof (ip6_header_t);
+	      ip_udp_encap_two (vm, b0, b1, (u8 *) & ue0->ue_hdrs,
+				(u8 *) & ue1->ue_hdrs, n_bytes, 0);
+	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+		{
+		  udp6_encap_trace_t *tr =
+		    vlib_add_trace (vm, node, b0, sizeof (*tr));
+		  tr->udp = ue0->ue_hdrs.ip6.ue_udp;
+		  tr->ip = ue0->ue_hdrs.ip6.ue_ip6;
+		}
+	      if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
+		{
+		  udp6_encap_trace_t *tr =
+		    vlib_add_trace (vm, node, b1, sizeof (*tr));
+		  tr->udp = ue1->ue_hdrs.ip6.ue_udp;
+		  tr->ip = ue1->ue_hdrs.ip6.ue_ip6;
+		}
+	    }
+	  else
+	    {
+	      const u8 n_bytes =
+		sizeof (udp_header_t) + sizeof (ip4_header_t);
+
+	      ip_udp_encap_two (vm, b0, b1,
+				(u8 *) & ue0->ue_hdrs,
+				(u8 *) & ue1->ue_hdrs, n_bytes, 1);
+
+	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+		{
+		  udp4_encap_trace_t *tr =
+		    vlib_add_trace (vm, node, b0, sizeof (*tr));
+		  tr->udp = ue0->ue_hdrs.ip4.ue_udp;
+		  tr->ip = ue0->ue_hdrs.ip4.ue_ip4;
+		}
+	      if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
+		{
+		  udp4_encap_trace_t *tr =
+		    vlib_add_trace (vm, node, b1, sizeof (*tr));
+		  tr->udp = ue1->ue_hdrs.ip4.ue_udp;
+		  tr->ip = ue1->ue_hdrs.ip4.ue_ip4;
+		}
+	    }
+
+	  next0 = ue0->ue_dpo.dpoi_next_node;
+	  next1 = ue1->ue_dpo.dpoi_next_node;
+	  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = ue0->ue_dpo.dpoi_index;
+	  vnet_buffer (b1)->ip.adj_index[VLIB_TX] = ue1->ue_dpo.dpoi_index;
+
+	  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, next0, uei0;
+	  vlib_buffer_t *b0;
+	  udp_encap_t *ue0;
+
+	  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);
+
+	  uei0 = vnet_buffer (b0)->ip.adj_index[VLIB_TX];
+
+	  /* Rewrite packet header and updates lengths. */
+	  ue0 = udp_encap_get (uei0);
+
+	  /* Paint */
+	  if (is_encap_v6)
+	    {
+	      const u8 n_bytes =
+		sizeof (udp_header_t) + sizeof (ip6_header_t);
+	      ip_udp_encap_one (vm, b0, (u8 *) & ue0->ue_hdrs.ip6, n_bytes,
+				0);
+
+	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+		{
+		  udp6_encap_trace_t *tr =
+		    vlib_add_trace (vm, node, b0, sizeof (*tr));
+		  tr->udp = ue0->ue_hdrs.ip6.ue_udp;
+		  tr->ip = ue0->ue_hdrs.ip6.ue_ip6;
+		}
+	    }
+	  else
+	    {
+	      const u8 n_bytes =
+		sizeof (udp_header_t) + sizeof (ip4_header_t);
+
+	      ip_udp_encap_one (vm, b0, (u8 *) & ue0->ue_hdrs.ip4, n_bytes,
+				1);
+
+	      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+		{
+		  udp4_encap_trace_t *tr =
+		    vlib_add_trace (vm, node, b0, sizeof (*tr));
+		  tr->udp = ue0->ue_hdrs.ip4.ue_udp;
+		  tr->ip = ue0->ue_hdrs.ip4.ue_ip4;
+		}
+	    }
+
+	  next0 = ue0->ue_dpo.dpoi_next_node;
+	  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = ue0->ue_dpo.dpoi_index;
+
+	  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
+udp4_encap (vlib_main_t * vm,
+	    vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return udp_encap_inline (vm, node, frame, 0);
+}
+
+static uword
+udp6_encap (vlib_main_t * vm,
+	    vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return udp_encap_inline (vm, node, frame, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (udp4_encap_node) = {
+  .function = udp4_encap,
+  .name = "udp4-encap",
+  .vector_size = sizeof (u32),
+
+  .format_trace = format_udp4_encap_trace,
+
+  .n_next_nodes = 0,
+};
+VLIB_NODE_FUNCTION_MULTIARCH (udp4_encap_node, udp4_encap);
+
+VLIB_REGISTER_NODE (udp6_encap_node) = {
+  .function = udp6_encap,
+  .name = "udp6-encap",
+  .vector_size = sizeof (u32),
+
+  .format_trace = format_udp6_encap_trace,
+
+  .n_next_nodes = 0,
+};
+VLIB_NODE_FUNCTION_MULTIARCH (udp6_encap_node, udp6_encap);
+/* *INDENT-ON* */
+
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/vnet_all_api_h.h b/src/vnet/vnet_all_api_h.h
index 936f0a5fac8..c71af079e11 100644
--- a/src/vnet/vnet_all_api_h.h
+++ b/src/vnet/vnet_all_api_h.h
@@ -61,6 +61,7 @@
 #include <vnet/ethernet/p2p_ethernet.api.h>
 #include <vnet/tcp/tcp.api.h>
 #include <vnet/dns/dns.api.h>
+#include <vnet/udp/udp.api.h>
 
 /*
  * fd.io coding-style-patch-verification: ON