A Protocol Independent Hierarchical FIB (VPP-352)

Main Enhancements:
 - Protocol Independent FIB API
 - Hierarchical FIB entries. Dynamic recursive route resolution.
 - Extranet Support.
 - Integration of IP and MPLS forwarding.
 - Separation of FIB and Adjacency databases.
 - Data-Plane Object forwarding model.

Change-Id: I52dc815c0d0aa8b493e3cf6b978568f3cc82296c
Signed-off-by: Neale Ranns <nranns@cisco.com>

4 files changed, 638 insertions, 287 deletions

diff --git a/vnet/vnet/gre/gre.c b/vnet/vnet/gre/gre.c
index f00977c8cd6..9f8adc79ff0 100644
--- a/vnet/vnet/gre/gre.c
+++ b/vnet/vnet/gre/gre.c
@@ -17,14 +17,10 @@
 
 #include <vnet/vnet.h>
 #include <vnet/gre/gre.h>
+#include <vnet/adj/adj.h>
 
 gre_main_t gre_main;
 
-typedef CLIB_PACKED (struct {
-  ip4_header_t ip4;
-  gre_header_t gre;
-}) ip4_and_gre_header_t;
-
 typedef struct {
   union {
     ip4_and_gre_header_t ip4_and_gre;
@@ -233,179 +229,39 @@ gre_interface_tx (vlib_main_t * vm,
       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 
       /* 
-       * As long as we have enough pkts left to process two pkts
-       * and prefetch two pkts...
+       * FIXME DUAL LOOP
        */
-      while (n_left_from >= 4 && n_left_to_next >= 2)
-	{
-          vlib_buffer_t * b0, * b1;
-          ip4_header_t * ip0, * ip1;
-          ip4_and_gre_union_t * h0, * h1;
-	  u32 bi0, next0, bi1, next1;
-	  __attribute__((unused)) u8 error0, error1;
-          u16 gre_protocol0, gre_protocol1;
-      
-	  /* Prefetch the 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);
-
-            /* 
-             * Prefetch packet data. We expect to overwrite
-             * the inbound L2 header with an ip header and a
-             * gre header. Might want to prefetch the last line
-             * of rewrite space as well; need profile data
-             */
-	    CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
-	    CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
-	  }
-
-          /* Pick up the next two buffer indices */
-	  bi0 = from[0];
-	  bi1 = from[1];
-
-          /* Speculatively enqueue them where we sent the last buffer */
-	  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);
-
-          vnet_buffer (b0)->sw_if_index[VLIB_TX] = t->outer_fib_index;
-          vnet_buffer (b1)->sw_if_index[VLIB_TX] = t->outer_fib_index;
-
-          if (PREDICT_FALSE(t->teb))
-          {
-            gre_protocol0 = clib_net_to_host_u16(GRE_PROTOCOL_teb);
-            gre_protocol1 = clib_net_to_host_u16(GRE_PROTOCOL_teb);
-          }
-          else
-          {
-            ip0 = vlib_buffer_get_current (b0);
-            gre_protocol0 = clib_net_to_host_u16 (0x800);
-            gre_protocol0 =
-                ((ip0->ip_version_and_header_length & 0xF0) == 0x60) ?
-                0x86DD : gre_protocol0;
-
-            ip1 = vlib_buffer_get_current (b1);
-            gre_protocol1 = clib_net_to_host_u16 (0x800);
-            gre_protocol1 =
-                ((ip1->ip_version_and_header_length & 0xF0) == 0x60) ?
-                0x86DD : gre_protocol1;
-          }
-
-          vlib_buffer_advance (b0, -sizeof(*h0));
-          vlib_buffer_advance (b1, -sizeof(*h1));
-
-          h0 = vlib_buffer_get_current (b0);
-          h1 = vlib_buffer_get_current (b1);
-          h0->as_u64[0] = 0;
-          h0->as_u64[1] = 0;
-          h0->as_u64[2] = 0;
-
-          h1->as_u64[0] = 0;
-          h1->as_u64[1] = 0;
-          h1->as_u64[2] = 0;
-
-          ip0 = &h0->ip4_and_gre.ip4;
-          h0->ip4_and_gre.gre.protocol = gre_protocol0;
-          ip0->ip_version_and_header_length = 0x45;
-          ip0->ttl = 254;
-          ip0->protocol = IP_PROTOCOL_GRE;
-
-          ip1 = &h1->ip4_and_gre.ip4;
-          h1->ip4_and_gre.gre.protocol = gre_protocol1;
-          ip1->ip_version_and_header_length = 0x45;
-          ip1->ttl = 254;
-          ip1->protocol = IP_PROTOCOL_GRE;
-
-          ip0->length = 
-            clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
-          ip1->length = 
-            clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b1));
-          ip0->src_address.as_u32 = t->tunnel_src.as_u32;
-          ip1->src_address.as_u32 = t->tunnel_src.as_u32;
-          ip0->dst_address.as_u32 = t->tunnel_dst.as_u32;
-          ip1->dst_address.as_u32 = t->tunnel_dst.as_u32;
-          ip0->checksum = ip4_header_checksum (ip0);
-          ip1->checksum = ip4_header_checksum (ip1);
-
-          /* ip4_lookup will route to the tunnel partner */
-          next0 = GRE_OUTPUT_NEXT_LOOKUP;
-          next1 = GRE_OUTPUT_NEXT_LOOKUP;
-          error0 = GRE_ERROR_NONE;
-          error1 = GRE_ERROR_NONE;
-
-          /* 
-           * Enqueue 2 pkts. This macro deals with next0 != next1,
-           * acquiring enqueue rights to the indicated next
-           * node input frame, etc.
-           */
-	  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;
+          u32 bi0, adj_index0, next0;
+	  const ip_adjacency_t * adj0;
+          const dpo_id_t *dpo0;
           ip4_header_t * ip0;
-          ip4_and_gre_union_t * h0;
-	  u32 bi0, next0;
-	  __attribute__((unused)) u8 error0;
-          u16 gre_protocol0;
-      
-	  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);
-
-          vnet_buffer (b0)->sw_if_index[VLIB_TX] = t->outer_fib_index;
+          vlib_buffer_t * b0;
+
+          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);
           ip0 = vlib_buffer_get_current (b0);
-          if (PREDICT_FALSE(t->teb))
-          {
-            gre_protocol0 = clib_net_to_host_u16(GRE_PROTOCOL_teb);
-          }
-          else
-          {
-            gre_protocol0 = clib_net_to_host_u16 (0x800);
-            gre_protocol0 =
-                ((ip0->ip_version_and_header_length & 0xF0) == 0x60) ?
-                0x86DD : gre_protocol0;
-          }
-
-          vlib_buffer_advance (b0, -sizeof(*h0));
-
-          h0 = vlib_buffer_get_current (b0);
-          h0->as_u64[0] = 0;
-          h0->as_u64[1] = 0;
-          h0->as_u64[2] = 0;
-
-          ip0 = &h0->ip4_and_gre.ip4;
-          h0->ip4_and_gre.gre.protocol = gre_protocol0;
-          ip0->ip_version_and_header_length = 0x45;
-          ip0->ttl = 254;
-          ip0->protocol = IP_PROTOCOL_GRE;
+
+          /* Fixup the checksum and len fields in the LISP tunnel encap
+           * that was applied at the midchain node */
           ip0->length = 
             clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
-          ip0->src_address.as_u32 = t->tunnel_src.as_u32;
-          ip0->dst_address.as_u32 = t->tunnel_dst.as_u32;
           ip0->checksum = ip4_header_checksum (ip0);
 
-          next0 = GRE_OUTPUT_NEXT_LOOKUP;
-          error0 = GRE_ERROR_NONE;
+          /* Follow the DPO on which the midchain is stacked */
+          adj_index0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
+	  adj0 = adj_get(adj_index0);
+          dpo0 = &adj0->sub_type.midchain.next_dpo;
+          next0 = dpo0->dpoi_next_node;
+          vnet_buffer(b0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
 
           if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED)) 
             {
diff --git a/vnet/vnet/gre/gre.h b/vnet/vnet/gre/gre.h
index ad599d2f09e..beb13d989ee 100644
--- a/vnet/vnet/gre/gre.h
+++ b/vnet/vnet/gre/gre.h
@@ -25,6 +25,7 @@
 #include <vnet/ip/ip4_packet.h>
 #include <vnet/pg/pg.h>
 #include <vnet/ip/format.h>
+#include <vnet/adj/adj_types.h>
 
 extern vnet_hw_interface_class_t gre_hw_interface_class;
 
@@ -50,12 +51,44 @@ typedef struct {
 } gre_protocol_info_t;
 
 typedef struct {
+  /**
+   * Linkage into the FIB object graph
+   */
+  fib_node_t node;
+
+  /**
+   * The tunnel's source/local address
+   */
   ip4_address_t tunnel_src;
+  /**
+   * The tunnel's destination/remote address
+   */
   ip4_address_t tunnel_dst;
+  /**
+   * The FIB in which the src.dst address are present
+   */
   u32 outer_fib_index;
   u32 hw_if_index;
   u32 sw_if_index;
   u8 teb;
+
+  /**
+   * The FIB entry sourced by the tunnel for its destination prefix
+   */
+  fib_node_index_t fib_entry_index;
+
+  /**
+   * The tunnel is a child of the FIB entry for its desintion. This is
+   * so it receives updates when the forwarding information for that entry
+   * changes.
+   * The tunnels sibling index on the FIB entry's dependency list.
+   */
+  u32 sibling_index;
+
+  /**
+   * The index of the midchain adjacency created for this tunnel
+   */
+  adj_index_t adj_index[FIB_LINK_NUM];
 } gre_tunnel_t;
 
 typedef struct {
@@ -80,6 +113,15 @@ typedef struct {
   vnet_main_t * vnet_main;
 } gre_main_t;
 
+/**
+ * @brief IPv4 and GRE header.
+ *
+*/
+typedef CLIB_PACKED (struct {
+  ip4_header_t ip4;
+  gre_header_t gre;
+}) ip4_and_gre_header_t;
+
 always_inline gre_protocol_info_t *
 gre_get_protocol_info (gre_main_t * em, gre_protocol_t protocol)
 {
diff --git a/vnet/vnet/gre/interface.c b/vnet/vnet/gre/interface.c
index 864c384b992..10e9ff9be8c 100644
--- a/vnet/vnet/gre/interface.c
+++ b/vnet/vnet/gre/interface.c
@@ -19,10 +19,24 @@
 #include <vnet/pg/pg.h>
 #include <vnet/gre/gre.h>
 #include <vnet/ip/format.h>
+#include <vnet/fib/ip4_fib.h>
+#include <vnet/adj/adj_midchain.h>
+#include <vnet/mpls/mpls.h>
+
+static inline u64
+gre_mk_key (const ip4_address_t *src,
+            const ip4_address_t *dst,
+            u32 out_fib_index)
+{
+  // FIXME. the fib index should be part of the key
+  return ((u64)src->as_u32 << 32 | (u64)dst->as_u32);
+}
 
-u8 * format_gre_tunnel (u8 * s, va_list * args)
+static u8 *
+format_gre_tunnel (u8 * s, va_list * args)
 {
   gre_tunnel_t * t = va_arg (*args, gre_tunnel_t *);
+  int detail = va_arg (*args, int);
   gre_main_t * gm = &gre_main;
 
   s = format (s,
@@ -32,11 +46,193 @@ u8 * format_gre_tunnel (u8 * s, va_list * args)
               format_ip4_address, &t->tunnel_dst,
               (t->teb ? "teb" : "ip"),
               t->outer_fib_index);
+  if (detail)
+  {
+      s = format (s, "\n  fib-entry:%d adj-ip4:%d adj-ip6:%d adj-mpls:%d",
+                  t->fib_entry_index,
+                  t->adj_index[FIB_LINK_IP4],
+                  t->adj_index[FIB_LINK_IP6],
+                  t->adj_index[FIB_LINK_MPLS]);
+  }
+
   return s;
 }
 
-int vnet_gre_add_del_tunnel
-  (vnet_gre_add_del_tunnel_args_t *a, u32 * sw_if_indexp)
+static gre_tunnel_t *
+gre_tunnel_db_find (const ip4_address_t *src,
+                    const ip4_address_t *dst,
+                    u32 out_fib_index)
+{
+  gre_main_t * gm = &gre_main;
+  uword * p;
+  u64 key;
+
+  key = gre_mk_key(src, dst, out_fib_index);
+
+  p = hash_get (gm->tunnel_by_key, key);
+
+  if (NULL == p)
+    return (NULL);
+
+  return (pool_elt_at_index (gm->tunnels, p[0]));
+}
+
+static void
+gre_tunnel_db_add (const gre_tunnel_t *t)
+{
+  gre_main_t * gm = &gre_main;
+  u64 key;
+
+  key = gre_mk_key(&t->tunnel_src, &t->tunnel_dst, t->outer_fib_index);
+  hash_set (gm->tunnel_by_key, key, t - gm->tunnels);
+}
+
+static void
+gre_tunnel_db_remove (const gre_tunnel_t *t)
+{
+  gre_main_t * gm = &gre_main;
+  u64 key;
+
+  key = gre_mk_key(&t->tunnel_src, &t->tunnel_dst, t->outer_fib_index);
+  hash_unset (gm->tunnel_by_key, key);
+}
+
+static gre_tunnel_t *
+gre_tunnel_from_fib_node (fib_node_t *node)
+{
+#if (CLIB_DEBUG > 0)
+    ASSERT(FIB_NODE_TYPE_GRE_TUNNEL == node->fn_type);
+#endif
+    return ((gre_tunnel_t*) (((char*)node) -
+                             STRUCT_OFFSET_OF(gre_tunnel_t, node)));
+}
+
+/*
+ * gre_tunnel_stack
+ *
+ * 'stack' (resolve the recursion for) the tunnel's midchain adjacency
+ */
+static void
+gre_tunnel_stack (gre_tunnel_t *gt)
+{
+    fib_link_t linkt;
+
+    /*
+     * find the adjacency that is contributed by the FIB entry
+     * that this tunnel resovles via, and use it as the next adj
+     * in the midchain
+     */
+    FOR_EACH_FIB_LINK(linkt)
+    {
+        if (ADJ_INDEX_INVALID != gt->adj_index[linkt])
+        {
+            adj_nbr_midchain_stack(
+                gt->adj_index[linkt],
+                fib_entry_contribute_ip_forwarding(gt->fib_entry_index));
+        }
+    }
+}
+
+/**
+ * Function definition to backwalk a FIB node
+ */
+static fib_node_back_walk_rc_t
+gre_tunnel_back_walk (fib_node_t *node,
+			   fib_node_back_walk_ctx_t *ctx)
+{
+    gre_tunnel_stack(gre_tunnel_from_fib_node(node));
+
+    return (FIB_NODE_BACK_WALK_CONTINUE);
+}
+
+/**
+ * Function definition to get a FIB node from its index
+ */
+static fib_node_t*
+gre_tunnel_fib_node_get (fib_node_index_t index)
+{
+    gre_tunnel_t * gt;
+    gre_main_t * gm;
+
+    gm  = &gre_main;
+    gt = pool_elt_at_index(gm->tunnels, index);
+
+    return (&gt->node);
+}
+
+/**
+ * Function definition to inform the FIB node that its last lock has gone.
+ */
+static void
+gre_tunnel_last_lock_gone (fib_node_t *node)
+{
+    /*
+     * The MPLS GRE tunnel is a root of the graph. As such
+     * it never has children and thus is never locked.
+     */
+    ASSERT(0);
+}
+
+/*
+ * Virtual function table registered by MPLS GRE tunnels
+ * for participation in the FIB object graph.
+ */
+const static fib_node_vft_t gre_vft = {
+    .fnv_get = gre_tunnel_fib_node_get,
+    .fnv_last_lock = gre_tunnel_last_lock_gone,
+    .fnv_back_walk = gre_tunnel_back_walk,
+};
+
+static int
+gre_proto_from_fib_link (fib_link_t link)
+{
+    switch (link)
+    {
+    case FIB_LINK_IP4:
+        return (GRE_PROTOCOL_ip4);
+    case FIB_LINK_IP6:
+        return (GRE_PROTOCOL_ip6);
+    case FIB_LINK_MPLS:
+        return (GRE_PROTOCOL_mpls_unicast);
+    }
+    ASSERT(0);
+    return (GRE_PROTOCOL_ip4);
+}
+
+static u8 *
+gre_rewrite (gre_tunnel_t * t,
+             fib_link_t link)
+{
+  ip4_and_gre_header_t * h0;
+  u8 * rewrite_data = 0;
+
+  vec_validate_init_empty (rewrite_data, sizeof (*h0) - 1, 0);
+
+  h0 = (ip4_and_gre_header_t *) rewrite_data;
+
+  if (t->teb)
+  {
+      h0->gre.protocol = clib_net_to_host_u16(GRE_PROTOCOL_teb);
+  }
+  else
+  {
+      h0->gre.protocol = clib_host_to_net_u16(gre_proto_from_fib_link(link));
+  }
+
+  h0->ip4.ip_version_and_header_length = 0x45;
+  h0->ip4.ttl = 254;
+  h0->ip4.protocol = IP_PROTOCOL_GRE;
+  /* $$$ fixup ip4 header length and checksum after-the-fact */
+  h0->ip4.src_address.as_u32 = t->tunnel_src.as_u32;
+  h0->ip4.dst_address.as_u32 = t->tunnel_dst.as_u32;
+  h0->ip4.checksum = ip4_header_checksum (&h0->ip4);
+
+  return (rewrite_data);
+}
+
+static int 
+vnet_gre_tunnel_add (vnet_gre_add_del_tunnel_args_t *a,
+                     u32 * sw_if_indexp)
 {
   gre_main_t * gm = &gre_main;
   vnet_main_t * vnm = gm->vnet_main;
@@ -44,49 +240,45 @@ int vnet_gre_add_del_tunnel
   gre_tunnel_t * t;
   vnet_hw_interface_t * hi;
   u32 hw_if_index, sw_if_index;
-  u32 slot;
   u32 outer_fib_index;
-  uword * p;
-  u64 key;
   u8 address[6];
   clib_error_t *error;
+  fib_link_t linkt;
+  u8 *rewrite;
 
-  key = (u64)a->src.as_u32 << 32 | (u64)a->dst.as_u32;
-  p = hash_get (gm->tunnel_by_key, key);
+  outer_fib_index = ip4_fib_index_from_table_id(a->outer_fib_id);
 
-  if (a->is_add) {
-    /* check if same src/dst pair exists */
-    if (p)
-      return VNET_API_ERROR_INVALID_VALUE;
+  if (~0 == outer_fib_index)
+    return VNET_API_ERROR_NO_SUCH_FIB;
 
-    p = hash_get (im->fib_index_by_table_id, a->outer_fib_id);
-    if (! p)
-      return VNET_API_ERROR_NO_SUCH_FIB;
+  t = gre_tunnel_db_find(&a->src, &a->dst, a->outer_fib_id);
 
-    outer_fib_index = p[0];
+  if (NULL != t)
+    return VNET_API_ERROR_INVALID_VALUE;
 
-    pool_get_aligned (gm->tunnels, t, CLIB_CACHE_LINE_BYTES);
-    memset (t, 0, sizeof (*t));
+  pool_get_aligned (gm->tunnels, t, CLIB_CACHE_LINE_BYTES);
+  memset (t, 0, sizeof (*t));
+  fib_node_init(&t->node, FIB_NODE_TYPE_GRE_TUNNEL);
 
-    if (vec_len (gm->free_gre_tunnel_hw_if_indices) > 0) {
-        vnet_interface_main_t * im = &vnm->interface_main;
+  if (vec_len (gm->free_gre_tunnel_hw_if_indices) > 0) {
+      vnet_interface_main_t * im = &vnm->interface_main;
 
-        hw_if_index = gm->free_gre_tunnel_hw_if_indices
+      hw_if_index = gm->free_gre_tunnel_hw_if_indices
           [vec_len (gm->free_gre_tunnel_hw_if_indices)-1];
-          _vec_len (gm->free_gre_tunnel_hw_if_indices) -= 1;
+      _vec_len (gm->free_gre_tunnel_hw_if_indices) -= 1;
 
-        hi = vnet_get_hw_interface (vnm, hw_if_index);
-        hi->dev_instance = t - gm->tunnels;
-        hi->hw_instance = hi->dev_instance;
+      hi = vnet_get_hw_interface (vnm, hw_if_index);
+      hi->dev_instance = t - gm->tunnels;
+      hi->hw_instance = hi->dev_instance;
 
-        /* clear old stats of freed tunnel before reuse */
-        sw_if_index = hi->sw_if_index;
-        vnet_interface_counter_lock(im);
-        vlib_zero_combined_counter
+      /* clear old stats of freed tunnel before reuse */
+      sw_if_index = hi->sw_if_index;
+      vnet_interface_counter_lock(im);
+      vlib_zero_combined_counter
           (&im->combined_sw_if_counters[VNET_INTERFACE_COUNTER_TX], sw_if_index);
-        vlib_zero_combined_counter
+      vlib_zero_combined_counter
           (&im->combined_sw_if_counters[VNET_INTERFACE_COUNTER_RX], sw_if_index);
-        vlib_zero_simple_counter
+      vlib_zero_simple_counter
           (&im->sw_if_counters[VNET_INTERFACE_COUNTER_DROP], sw_if_index);
         vnet_interface_counter_unlock(im);
     } else {
@@ -111,67 +303,186 @@ int vnet_gre_add_del_tunnel
           return VNET_API_ERROR_INVALID_REGISTRATION;
         }
       } else {
-        hw_if_index = vnet_register_interface
-          (vnm, gre_device_class.index, t - gm->tunnels,
-           gre_hw_interface_class.index,
-           t - gm->tunnels);
+	hw_if_index = vnet_register_interface
+	    (vnm, gre_device_class.index, t - gm->tunnels,
+	     gre_hw_interface_class.index,
+	     t - gm->tunnels);
       }
       hi = vnet_get_hw_interface (vnm, hw_if_index);
       sw_if_index = hi->sw_if_index;
     }
 
-    t->hw_if_index = hw_if_index;
-    t->outer_fib_index = outer_fib_index;
-    t->sw_if_index = sw_if_index;
+  t->hw_if_index = hw_if_index;
+  t->outer_fib_index = outer_fib_index;
+  t->sw_if_index = sw_if_index;
 
-    vec_validate_init_empty (gm->tunnel_index_by_sw_if_index, sw_if_index, ~0);
-    gm->tunnel_index_by_sw_if_index[sw_if_index] = t - gm->tunnels;
+  vec_validate_init_empty (gm->tunnel_index_by_sw_if_index, sw_if_index, ~0);
+  gm->tunnel_index_by_sw_if_index[sw_if_index] = t - gm->tunnels;
 
-    vec_validate (im->fib_index_by_sw_if_index, sw_if_index);
-    im->fib_index_by_sw_if_index[sw_if_index] = t->outer_fib_index;
+  vec_validate (im->fib_index_by_sw_if_index, sw_if_index);
+  im->fib_index_by_sw_if_index[sw_if_index] = t->outer_fib_index;
+  ip4_sw_interface_enable_disable(sw_if_index, 1);
 
-    hi->min_packet_bytes = 64 + sizeof (gre_header_t) + sizeof (ip4_header_t);
-    hi->per_packet_overhead_bytes =
+  hi->min_packet_bytes = 64 + sizeof (gre_header_t) + sizeof (ip4_header_t);
+  hi->per_packet_overhead_bytes =
       /* preamble */ 8 + /* inter frame gap */ 12;
 
-    /* Standard default gre MTU. */
-    hi->max_l3_packet_bytes[VLIB_RX] = hi->max_l3_packet_bytes[VLIB_TX] = 9000;
+  /* Standard default gre MTU. */
+  hi->max_l3_packet_bytes[VLIB_RX] = hi->max_l3_packet_bytes[VLIB_TX] = 9000;
+
+  clib_memcpy (&t->tunnel_src, &a->src, sizeof (t->tunnel_src));
+  clib_memcpy (&t->tunnel_dst, &a->dst, sizeof (t->tunnel_dst));
+
+  gre_tunnel_db_add(t);
+
+  /*
+   * source the FIB entry for the tunnel's destination
+   * and become a child thereof. The tunnel will then get poked
+   * when the forwarding for the entry updates, and the tunnel can
+   * re-stack accordingly
+   */
+  const fib_prefix_t tun_dst_pfx = {
+      .fp_len = 32,
+      .fp_proto = FIB_PROTOCOL_IP4,
+      .fp_addr = {
+          .ip4 = t->tunnel_dst,
+      }
+  };
+
+  t->fib_entry_index =
+      fib_table_entry_special_add(outer_fib_index,
+                                  &tun_dst_pfx,
+                                  FIB_SOURCE_RR,
+                                  FIB_ENTRY_FLAG_NONE,
+                                  ADJ_INDEX_INVALID);
+  t->sibling_index =
+      fib_entry_child_add(t->fib_entry_index,
+                          FIB_NODE_TYPE_GRE_TUNNEL,
+                          t - gm->tunnels);
+
+  /*
+   * create and update the midchain adj this tunnel sources.
+   * We could be smarter here and trigger this on an interface proto enable,
+   * like we do for MPLS.
+   */
+  for (linkt = FIB_LINK_IP4; linkt <= FIB_LINK_IP6; linkt++)
+  {
+      t->adj_index[linkt] = adj_nbr_add_or_lock(FIB_PROTOCOL_IP4,
+                                                linkt,
+                                                &zero_addr,
+                                                sw_if_index);
+
+      rewrite = gre_rewrite(t, linkt);
+      adj_nbr_midchain_update_rewrite(t->adj_index[linkt],
+                                      hi->tx_node_index,
+                                      rewrite);
+      vec_free(rewrite);
+  }
+  t->adj_index[FIB_LINK_MPLS] = ADJ_INDEX_INVALID;
 
-    t->teb = a->teb;
-    clib_memcpy (&t->tunnel_src, &a->src, sizeof (t->tunnel_src));
-    clib_memcpy (&t->tunnel_dst, &a->dst, sizeof (t->tunnel_dst));
+  t->teb = a->teb;
+  clib_memcpy (&t->tunnel_src, &a->src, sizeof (t->tunnel_src));
+  clib_memcpy (&t->tunnel_dst, &a->dst, sizeof (t->tunnel_dst));
+  gre_tunnel_stack(t);
 
-    hash_set (gm->tunnel_by_key, key, t - gm->tunnels);
+  if (sw_if_indexp)
+    *sw_if_indexp = sw_if_index;
 
-    slot = vlib_node_add_named_next_with_slot
-      (vnm->vlib_main, hi->tx_node_index, "ip4-lookup", GRE_OUTPUT_NEXT_LOOKUP);
+  return 0;
+}
 
-    ASSERT (slot == GRE_OUTPUT_NEXT_LOOKUP);
+static int 
+vnet_gre_tunnel_delete (vnet_gre_add_del_tunnel_args_t *a,
+                        u32 * sw_if_indexp)
+{
+  gre_main_t * gm = &gre_main;
+  vnet_main_t * vnm = gm->vnet_main;
+  gre_tunnel_t * t;
+  fib_link_t linkt;
+  u32 sw_if_index;
+
+  t = gre_tunnel_db_find(&a->src, &a->dst, a->outer_fib_id);
 
-  } else { /* !is_add => delete */
-    /* tunnel needs to exist */
-    if (! p)
-      return VNET_API_ERROR_NO_SUCH_ENTRY;
+  if (NULL == t)
+    return VNET_API_ERROR_NO_SUCH_ENTRY;
 
-    t = pool_elt_at_index (gm->tunnels, p[0]);
+  sw_if_index = t->sw_if_index;
+  vnet_sw_interface_set_flags (vnm, sw_if_index, 0 /* down */);
+  /* make sure tunnel is removed from l2 bd or xconnect */
+  set_int_l2_mode(gm->vlib_main, vnm, MODE_L3, sw_if_index, 0, 0, 0, 0);
+  vec_add1 (gm->free_gre_tunnel_hw_if_indices, t->hw_if_index);
+  gm->tunnel_index_by_sw_if_index[sw_if_index] = ~0;
+  ip4_sw_interface_enable_disable(sw_if_index, 0);
 
-    sw_if_index = t->sw_if_index;
-    vnet_sw_interface_set_flags (vnm, sw_if_index, 0 /* down */);
-    /* make sure tunnel is removed from l2 bd or xconnect */
-    set_int_l2_mode(gm->vlib_main, vnm, MODE_L3, sw_if_index, 0, 0, 0, 0);
-    vec_add1 (gm->free_gre_tunnel_hw_if_indices, t->hw_if_index);
-    gm->tunnel_index_by_sw_if_index[sw_if_index] = ~0;
+  fib_entry_child_remove(t->fib_entry_index,
+                         t->sibling_index);
+  fib_table_entry_delete_index(t->fib_entry_index,
+                               FIB_SOURCE_RR);
 
-    hash_unset (gm->tunnel_by_key, key);
-    pool_put (gm->tunnels, t);
+  FOR_EACH_FIB_LINK(linkt)
+  {
+      adj_unlock(t->adj_index[linkt]);
   }
 
+  gre_tunnel_db_remove(t);
+  fib_node_deinit(&t->node);
+  pool_put (gm->tunnels, t);
+
   if (sw_if_indexp)
     *sw_if_indexp = sw_if_index;
 
   return 0;
 }
 
+int
+vnet_gre_add_del_tunnel (vnet_gre_add_del_tunnel_args_t *a,
+                         u32 * sw_if_indexp)
+{
+  if (a->is_add)
+    return (vnet_gre_tunnel_add(a, sw_if_indexp));
+  else
+    return (vnet_gre_tunnel_delete(a, sw_if_indexp));
+}
+
+static void
+gre_sw_interface_mpls_state_change (u32 sw_if_index,
+                                    u32 is_enable)
+{
+  gre_main_t *gm = &gre_main;
+  vnet_hw_interface_t * hi;
+  gre_tunnel_t *t;
+  u8 *rewrite;
+
+  if ((vec_len(gm->tunnel_index_by_sw_if_index) < sw_if_index) ||
+      (~0 == gm->tunnel_index_by_sw_if_index[sw_if_index]))
+      return;
+
+  t = pool_elt_at_index(gm->tunnels,
+                        gm->tunnel_index_by_sw_if_index[sw_if_index]);
+
+  if (is_enable)
+    {
+      hi = vnet_get_hw_interface (vnet_get_main(), t->hw_if_index);
+      t->adj_index[FIB_LINK_MPLS] =
+          adj_nbr_add_or_lock(FIB_PROTOCOL_IP4,
+                              FIB_LINK_MPLS,
+                              &zero_addr,
+                              sw_if_index);
+
+      rewrite = gre_rewrite(t, FIB_LINK_MPLS);
+      adj_nbr_midchain_update_rewrite(t->adj_index[FIB_LINK_MPLS],
+                                      hi->tx_node_index,
+                                      rewrite);
+      vec_free(rewrite);
+    }
+  else
+    {
+      adj_unlock(t->adj_index[FIB_LINK_MPLS]);
+      t->adj_index[FIB_LINK_MPLS] = ADJ_INDEX_INVALID;
+    }
+
+  gre_tunnel_stack(t);
+}
 
 static clib_error_t *
 create_gre_tunnel_command_fn (vlib_main_t * vm,
@@ -216,13 +527,15 @@ create_gre_tunnel_command_fn (vlib_main_t * vm,
       return clib_error_return (0, "src and dst are identical");
 
   memset (a, 0, sizeof (*a));
-  a->is_add = is_add;
   a->outer_fib_id = outer_fib_id;
   a->teb = teb;
   clib_memcpy(&a->src, &src, sizeof(src));
   clib_memcpy(&a->dst, &dst, sizeof(dst));
 
-  rv = vnet_gre_add_del_tunnel (a, &sw_if_index);
+  if (is_add)
+    rv = vnet_gre_tunnel_add(a, &sw_if_index);
+  else
+    rv = vnet_gre_tunnel_delete(a, &sw_if_index);
 
   switch(rv)
     {
@@ -255,14 +568,32 @@ show_gre_tunnel_command_fn (vlib_main_t * vm,
 {
   gre_main_t * gm = &gre_main;
   gre_tunnel_t * t;
+  u32 ti = ~0;
 
   if (pool_elts (gm->tunnels) == 0)
     vlib_cli_output (vm, "No GRE tunnels configured...");
 
-  pool_foreach (t, gm->tunnels,
-  ({
-    vlib_cli_output (vm, "%U", format_gre_tunnel, t);
-  }));
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "%d", &ti))
+        ;
+      else
+        break;
+    }
+
+  if (~0 == ti)
+    {
+      pool_foreach (t, gm->tunnels,
+      ({
+          vlib_cli_output (vm, "%U", format_gre_tunnel, t, 0);
+      }));
+    }
+  else
+  {
+      t = pool_elt_at_index(gm->tunnels, ti);
+
+      vlib_cli_output (vm, "%U", format_gre_tunnel, t, 1);
+  }
 
   return 0;
 }
@@ -275,6 +606,11 @@ VLIB_CLI_COMMAND (show_gre_tunnel_command, static) = {
 /* force inclusion from application's main.c */
 clib_error_t *gre_interface_init (vlib_main_t *vm)
 {
+  vec_add1(mpls_main.mpls_interface_state_change_callbacks,
+           gre_sw_interface_mpls_state_change);
+
+  fib_node_register_type(FIB_NODE_TYPE_GRE_TUNNEL, &gre_vft);
+
   return 0;
 }
 VLIB_INIT_FUNCTION(gre_interface_init);
diff --git a/vnet/vnet/gre/node.c b/vnet/vnet/gre/node.c
index d5ea4b65ddb..b55f5511916 100644
--- a/vnet/vnet/gre/node.c
+++ b/vnet/vnet/gre/node.c
@@ -18,6 +18,7 @@
 #include <vlib/vlib.h>
 #include <vnet/pg/pg.h>
 #include <vnet/gre/gre.h>
+#include <vnet/mpls/mpls.h>
 #include <vppinfra/sparse_vec.h>
 
 #define foreach_gre_input_next			\
@@ -25,7 +26,8 @@ _(PUNT, "error-punt")                           \
 _(DROP, "error-drop")                           \
 _(ETHERNET_INPUT, "ethernet-input")             \
 _(IP4_INPUT, "ip4-input")                       \
-_(IP6_INPUT, "ip6-input")			
+_(IP6_INPUT, "ip6-input")			\
+_(MPLS_INPUT, "mpls-input")
 
 typedef enum {
 #define _(s,n) GRE_INPUT_NEXT_##s,
@@ -66,13 +68,17 @@ gre_input (vlib_main_t * vm,
 	   vlib_frame_t * from_frame)
 {
   gre_main_t * gm = &gre_main;
+  mpls_main_t * mm = &mpls_main;
+  ip4_main_t * ip4m = &ip4_main;
   gre_input_runtime_t * rt = (void *) node->runtime_data;
   __attribute__((unused)) u32 n_left_from, next_index, * from, * to_next;
   u64 cached_tunnel_key = (u64) ~0;
-  u32 cached_tunnel_sw_if_index = 0, tunnel_sw_if_index;
+  u32 cached_tunnel_sw_if_index = 0, tunnel_sw_if_index = 0;
   u32 cached_tunnel_fib_index = 0, tunnel_fib_index;
 
   u32 cpu_index = os_get_cpu_number();
+  u32 len;
+  vnet_interface_main_t *im = &gm->vnet_main->interface_main;
 
   from = vlib_frame_vector_args (from_frame);
   n_left_from = from_frame->n_vectors;
@@ -141,7 +147,7 @@ gre_input (vlib_main_t * vm,
 	  /* Index sparse array with network byte order. */
 	  protocol0 = h0->protocol;
 	  protocol1 = h1->protocol;
-	  sparse_vec_index2 (rt->next_by_protocol, protocol0, protocol1, 
+	  sparse_vec_index2 (rt->next_by_protocol, protocol0, protocol1,
                              &i0, &i1);
           next0 = vec_elt(rt->next_by_protocol, i0);
           next1 = vec_elt(rt->next_by_protocol, i1);
@@ -154,10 +160,10 @@ gre_input (vlib_main_t * vm,
           version1 = clib_net_to_host_u16 (h1->flags_and_version);
           verr1 =  version1 & GRE_VERSION_MASK;
 
-          b0->error = verr0 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION] 
+          b0->error = verr0 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION]
               : b0->error;
           next0 = verr0 ? GRE_INPUT_NEXT_DROP : next0;
-          b1->error = verr1 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION] 
+          b1->error = verr1 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION]
               : b1->error;
           next1 = verr1 ? GRE_INPUT_NEXT_DROP : next1;
 
@@ -176,7 +182,6 @@ gre_input (vlib_main_t * vm,
                   gre_tunnel_t * t;
                   uword * p;
 
-                  ip4_main_t * ip4m = &ip4_main;
                   p = hash_get (gm->tunnel_by_key, key);
                   if (!p)
                     {
@@ -199,19 +204,56 @@ gre_input (vlib_main_t * vm,
                   tunnel_sw_if_index = cached_tunnel_sw_if_index;
                   tunnel_fib_index = cached_tunnel_fib_index;
                 }
+            }
+          else if (PREDICT_TRUE(next0 == GRE_INPUT_NEXT_MPLS_INPUT))
+            {
+              u64 key = ((u64)(vnet_buffer(b0)->gre.dst) << 32) |
+                         (u64)(vnet_buffer(b0)->gre.src);
+
+              if (cached_tunnel_key != key)
+                {
+                  vnet_hw_interface_t * hi;
+                  mpls_gre_tunnel_t * t;
+                  uword * p;
 
-              u32 len = vlib_buffer_length_in_chain (vm, b0);
-              vnet_interface_main_t *im = &gm->vnet_main->interface_main;
-              vlib_increment_combined_counter (im->combined_sw_if_counters
-                                               + VNET_INTERFACE_COUNTER_RX,
-                                               cpu_index,
-                                               tunnel_sw_if_index,
-                                               1 /* packets */,
-                                               len /* bytes */);
-
-              vnet_buffer(b0)->sw_if_index[VLIB_TX] = tunnel_fib_index;
-              vnet_buffer(b0)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;
+                  p = hash_get (gm->tunnel_by_key, key);
+                  if (!p)
+                    {
+                      next0 = GRE_INPUT_NEXT_DROP;
+                      b0->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
+                      goto drop0;
+                    }
+                  t = pool_elt_at_index (mm->gre_tunnels, p[0]);
+                  hi = vnet_get_hw_interface (gm->vnet_main,
+                                              t->hw_if_index);
+                  tunnel_sw_if_index = hi->sw_if_index;
+                  tunnel_fib_index = vec_elt (ip4m->fib_index_by_sw_if_index,
+                                              tunnel_sw_if_index);
+
+                  cached_tunnel_sw_if_index = tunnel_sw_if_index;
+                  cached_tunnel_fib_index = tunnel_fib_index;
+                }
+              else
+                {
+                  tunnel_sw_if_index = cached_tunnel_sw_if_index;
+                  tunnel_fib_index = cached_tunnel_fib_index;
+                }
             }
+          else
+            {
+		next0 = GRE_INPUT_NEXT_DROP;
+                goto drop0;
+            }
+          len = vlib_buffer_length_in_chain (vm, b0);
+          vlib_increment_combined_counter (im->combined_sw_if_counters
+                                           + VNET_INTERFACE_COUNTER_RX,
+                                           cpu_index,
+                                           tunnel_sw_if_index,
+                                           1 /* packets */,
+                                           len /* bytes */);
+
+          vnet_buffer(b0)->sw_if_index[VLIB_TX] = tunnel_fib_index;
+          vnet_buffer(b0)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;
 
 drop0:
           if (PREDICT_FALSE(next1 == GRE_INPUT_NEXT_IP4_INPUT
@@ -227,7 +269,6 @@ drop0:
                   gre_tunnel_t * t;
                   uword * p;
 
-                  ip4_main_t * ip4m = &ip4_main;
                   p = hash_get (gm->tunnel_by_key, key);
                   if (!p)
                     {
@@ -250,23 +291,62 @@ drop0:
                   tunnel_sw_if_index = cached_tunnel_sw_if_index;
                   tunnel_fib_index = cached_tunnel_fib_index;
                 }
+            }
+          else if (PREDICT_TRUE(next1 == GRE_INPUT_NEXT_MPLS_INPUT))
+            {
+              u64 key = ((u64)(vnet_buffer(b1)->gre.dst) << 32) |
+                         (u64)(vnet_buffer(b1)->gre.src);
 
-              u32 len = vlib_buffer_length_in_chain (vm, b1);
-              vnet_interface_main_t *im = &gm->vnet_main->interface_main;
-              vlib_increment_combined_counter (im->combined_sw_if_counters
-                                               + VNET_INTERFACE_COUNTER_RX,
-                                               cpu_index,
-                                               tunnel_sw_if_index,
-                                               1 /* packets */,
-                                               len /* bytes */);
-
-              vnet_buffer(b1)->sw_if_index[VLIB_TX] = tunnel_fib_index;
-              vnet_buffer(b1)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;
+              if (cached_tunnel_key != key)
+                {
+                  vnet_hw_interface_t * hi;
+                  mpls_gre_tunnel_t * t;
+                  uword * p;
+
+                  ip4_main_t * ip4m = &ip4_main;
+                  p = hash_get (gm->tunnel_by_key, key);
+                  if (!p)
+                    {
+                      next1 = GRE_INPUT_NEXT_DROP;
+                      b1->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
+                      goto drop1;
+                    }
+                  t = pool_elt_at_index (mm->gre_tunnels, p[0]);
+                  hi = vnet_get_hw_interface (gm->vnet_main,
+                                              t->hw_if_index);
+                  tunnel_sw_if_index = hi->sw_if_index;
+                  tunnel_fib_index = vec_elt (ip4m->fib_index_by_sw_if_index,
+                                              tunnel_sw_if_index);
+
+                  cached_tunnel_sw_if_index = tunnel_sw_if_index;
+                  cached_tunnel_fib_index = tunnel_fib_index;
+                }
+              else
+                {
+                  tunnel_sw_if_index = cached_tunnel_sw_if_index;
+                  tunnel_fib_index = cached_tunnel_fib_index;
+                }
             }
+          else
+            {
+		next1 = GRE_INPUT_NEXT_DROP;
+                goto drop1;
+            }
+          len = vlib_buffer_length_in_chain (vm, b1);
+          vlib_increment_combined_counter (im->combined_sw_if_counters
+                                           + VNET_INTERFACE_COUNTER_RX,
+                                           cpu_index,
+                                           tunnel_sw_if_index,
+                                           1 /* packets */,
+                                           len /* bytes */);
+
+          vnet_buffer(b1)->sw_if_index[VLIB_TX] = tunnel_fib_index;
+          vnet_buffer(b1)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;
+
 drop1:
-          if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED)) 
+          if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
             {
-              gre_rx_trace_t *tr = vlib_add_trace (vm, node, 
+              gre_rx_trace_t *tr = vlib_add_trace (vm, node,
                                                    b0, sizeof (*tr));
               tr->tunnel_id = ~0;
               tr->length = ip0->length;
@@ -274,9 +354,9 @@ drop1:
               tr->dst.as_u32 = ip0->dst_address.as_u32;
             }
 
-          if (PREDICT_FALSE(b1->flags & VLIB_BUFFER_IS_TRACED)) 
+          if (PREDICT_FALSE(b1->flags & VLIB_BUFFER_IS_TRACED))
             {
-              gre_rx_trace_t *tr = vlib_add_trace (vm, node, 
+              gre_rx_trace_t *tr = vlib_add_trace (vm, node,
                                                    b1, sizeof (*tr));
               tr->tunnel_id = ~0;
               tr->length = ip1->length;
@@ -336,6 +416,7 @@ drop1:
           /* For IP payload we need to find source interface
              so we can increase counters and help forward node to
              pick right FIB */
+          /* RPF check for ip4/ip6 input */
           if (PREDICT_FALSE(next0 == GRE_INPUT_NEXT_IP4_INPUT
                             || next0 == GRE_INPUT_NEXT_IP6_INPUT
                             || next0 == GRE_INPUT_NEXT_ETHERNET_INPUT))
@@ -349,7 +430,6 @@ drop1:
                   gre_tunnel_t * t;
                   uword * p;
 
-                  ip4_main_t * ip4m = &ip4_main;
                   p = hash_get (gm->tunnel_by_key, key);
                   if (!p)
                     {
@@ -372,26 +452,63 @@ drop1:
                   tunnel_sw_if_index = cached_tunnel_sw_if_index;
                   tunnel_fib_index = cached_tunnel_fib_index;
                 }
+            }
+          else if (PREDICT_TRUE(next0 == GRE_INPUT_NEXT_MPLS_INPUT))
+            {
+              u64 key = ((u64)(vnet_buffer(b0)->gre.dst) << 32) |
+                         (u64)(vnet_buffer(b0)->gre.src);
 
-              u32 len = vlib_buffer_length_in_chain (vm, b0);
-              vnet_interface_main_t *im = &gm->vnet_main->interface_main;
-              vlib_increment_combined_counter (im->combined_sw_if_counters
-                                               + VNET_INTERFACE_COUNTER_RX,
-                                               cpu_index,
-                                               tunnel_sw_if_index,
-                                               1 /* packets */,
-                                               len /* bytes */);
-
-              vnet_buffer(b0)->sw_if_index[VLIB_TX] = tunnel_fib_index;
-              vnet_buffer(b0)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;
+              if (cached_tunnel_key != key)
+                {
+                  vnet_hw_interface_t * hi;
+                  mpls_gre_tunnel_t * t;
+                  uword * p;
+
+                  p = hash_get (gm->tunnel_by_key, key);
+                  if (!p)
+                    {
+                      next0 = GRE_INPUT_NEXT_DROP;
+                      b0->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
+                      goto drop;
+                    }
+                  t = pool_elt_at_index (mm->gre_tunnels, p[0]);
+                  hi = vnet_get_hw_interface (gm->vnet_main,
+                                              t->hw_if_index);
+                  tunnel_sw_if_index = hi->sw_if_index;
+                  tunnel_fib_index = vec_elt (ip4m->fib_index_by_sw_if_index,
+                                              tunnel_sw_if_index);
+
+                  cached_tunnel_sw_if_index = tunnel_sw_if_index;
+                  cached_tunnel_fib_index = tunnel_fib_index;
+                }
+              else
+                {
+                  tunnel_sw_if_index = cached_tunnel_sw_if_index;
+                  tunnel_fib_index = cached_tunnel_fib_index;
+                }
+            }
+          else
+            {
+		next0 = GRE_INPUT_NEXT_DROP;
+                goto drop;
             }
+          len = vlib_buffer_length_in_chain (vm, b0);
+          vlib_increment_combined_counter (im->combined_sw_if_counters
+                                           + VNET_INTERFACE_COUNTER_RX,
+                                           cpu_index,
+                                           tunnel_sw_if_index,
+                                           1 /* packets */,
+                                           len /* bytes */);
+
+          vnet_buffer(b0)->sw_if_index[VLIB_TX] = tunnel_fib_index;
+          vnet_buffer(b0)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;
 
 drop:
           if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED)) 
             {
               gre_rx_trace_t *tr = vlib_add_trace (vm, node, 
                                                    b0, sizeof (*tr));
-              tr->tunnel_id = ~0;
+              tr->tunnel_id = tunnel_sw_if_index;
               tr->length = ip0->length;
               tr->src.as_u32 = ip0->src_address.as_u32;
               tr->dst.as_u32 = ip0->dst_address.as_u32;
@@ -509,7 +626,7 @@ static clib_error_t * gre_input_init (vlib_main_t * vm)
   ASSERT(ip4_input);
   ip6_input = vlib_get_node_by_name (vm, (u8 *)"ip6-input");
   ASSERT(ip6_input);
-  mpls_unicast_input = vlib_get_node_by_name (vm, (u8 *)"mpls-gre-input");
+  mpls_unicast_input = vlib_get_node_by_name (vm, (u8 *)"mpls-input");
   ASSERT(mpls_unicast_input);
 
   gre_register_input_protocol (vm, GRE_PROTOCOL_teb,