VPP-142 Recursive route sending traffic to wrong interface

Indirect routes should always result in an indriect adjacency even when the route's next-hop is covered by a connceted, since the covering route may change and no tracking is in place.
Some de-duplication of code for installing indirect routes via the CLI and API.

Change-Id: I7a440ffba43ae3990b68cb407244c06bd0827534
Signed-off-by: Neale <nranns@cisco.com>

6 files changed, 249 insertions, 185 deletions

diff --git a/vnet/vnet/ip/ip4.h b/vnet/vnet/ip/ip4.h
index 7ed5bf5e..5ea4ebf5 100644
--- a/vnet/vnet/ip/ip4.h
+++ b/vnet/vnet/ip/ip4.h
@@ -355,6 +355,13 @@ void ip4_add_del_route_next_hop (ip4_main_t * im,
                                  u32 next_hop_weight, u32 adj_index, 
                                  u32 explicit_fib_index);
 
+u32
+ip4_route_get_next_hop_adj (ip4_main_t * im,
+			    u32 fib_index,
+			    ip4_address_t *next_hop,
+			    u32 next_hop_sw_if_index,
+			    u32 explicit_fib_index);
+
 void *
 ip4_get_route (ip4_main_t * im,
 	       u32 fib_index_or_table_id,
diff --git a/vnet/vnet/ip/ip4_forward.c b/vnet/vnet/ip/ip4_forward.c
index 35c42d82..97e472b6 100644
--- a/vnet/vnet/ip/ip4_forward.c
+++ b/vnet/vnet/ip/ip4_forward.c
@@ -274,6 +274,85 @@ void ip4_add_del_route (ip4_main_t * im, ip4_add_del_route_args_t * a)
     ip_del_adjacency (lm, old_adj_index);
 }
 
+
+u32
+ip4_route_get_next_hop_adj (ip4_main_t * im,
+			    u32 fib_index,
+			    ip4_address_t *next_hop,
+			    u32 next_hop_sw_if_index,
+			    u32 explicit_fib_index)
+{
+  ip_lookup_main_t * lm = &im->lookup_main;
+  vnet_main_t * vnm = vnet_get_main();
+  uword * nh_hash, * nh_result;
+  int is_interface_next_hop;
+  u32 nh_adj_index;
+  ip4_fib_t * fib;
+
+  fib = vec_elt_at_index (im->fibs, fib_index);
+
+  is_interface_next_hop = next_hop->data_u32 == 0;
+  if (is_interface_next_hop)
+    {
+      nh_result = hash_get (im->interface_route_adj_index_by_sw_if_index, next_hop_sw_if_index);
+      if (nh_result)
+	  nh_adj_index = *nh_result;
+      else
+        {
+	   ip_adjacency_t * adj;
+	   adj = ip_add_adjacency (lm, /* template */ 0, /* block size */ 1,
+				   &nh_adj_index);
+	   ip4_adjacency_set_interface_route (vnm, adj, next_hop_sw_if_index, /* if_address_index */ ~0);
+	   ip_call_add_del_adjacency_callbacks (lm, nh_adj_index, /* is_del */ 0);
+	   hash_set (im->interface_route_adj_index_by_sw_if_index, next_hop_sw_if_index, nh_adj_index);
+	}
+    }
+  else if (next_hop_sw_if_index == ~0)
+    {
+      /* next-hop is recursive. we always need a indirect adj
+       * for recursive paths. Any LPM we perform now will give
+       * us a valid adj, but without tracking the next-hop we
+       * have no way to keep it valid.
+       */
+      ip_adjacency_t add_adj;
+      memset (&add_adj, 0, sizeof(add_adj));
+      add_adj.n_adj = 1;
+      add_adj.lookup_next_index = IP_LOOKUP_NEXT_INDIRECT;
+      add_adj.indirect.next_hop.ip4.as_u32 = next_hop->as_u32;
+      add_adj.explicit_fib_index = explicit_fib_index;
+      ip_add_adjacency (lm, &add_adj, 1, &nh_adj_index);
+    }
+  else
+    {
+      nh_hash = fib->adj_index_by_dst_address[32];
+      nh_result = hash_get (nh_hash, next_hop->data_u32);
+
+      /* Next hop must be known. */
+      if (! nh_result)
+        {
+	  ip_adjacency_t * adj;
+
+	  /* no /32 exists, get the longest prefix match */
+	  nh_adj_index = ip4_fib_lookup_with_table (im, fib_index,
+						    next_hop, 0);
+	  adj = ip_get_adjacency (lm, nh_adj_index);
+	  /* if ARP interface adjacency is present, we need to
+	     install ARP adjaceny for specific next hop */
+	  if (adj->lookup_next_index == IP_LOOKUP_NEXT_ARP &&
+	      adj->arp.next_hop.ip4.as_u32 == 0)
+	    {
+	      nh_adj_index = vnet_arp_glean_add(fib_index, next_hop);
+	    }
+	}
+      else
+        {
+	  nh_adj_index = *nh_result;
+	}
+    }
+
+  return (nh_adj_index);
+}
+
 void
 ip4_add_del_route_next_hop (ip4_main_t * im,
 			    u32 flags,
@@ -291,11 +370,9 @@ ip4_add_del_route_next_hop (ip4_main_t * im,
   u32 dst_address_u32, old_mp_adj_index, new_mp_adj_index;
   u32 dst_adj_index, nh_adj_index;
   uword * dst_hash, * dst_result;
-  uword * nh_hash, * nh_result;
   ip_adjacency_t * dst_adj;
   ip_multipath_adjacency_t * old_mp, * new_mp;
   int is_del = (flags & IP4_ROUTE_FLAG_DEL) != 0;
-  int is_interface_next_hop;
   clib_error_t * error = 0;
 
   if (explicit_fib_index == (u32)~0)
@@ -304,61 +381,14 @@ ip4_add_del_route_next_hop (ip4_main_t * im,
       fib_index = explicit_fib_index;
 
   fib = vec_elt_at_index (im->fibs, fib_index);
-  
+
   /* Lookup next hop to be added or deleted. */
-  is_interface_next_hop = next_hop->data_u32 == 0;
   if (adj_index == (u32)~0)
     {
-      if (is_interface_next_hop)
-        {
-          nh_result = hash_get (im->interface_route_adj_index_by_sw_if_index, next_hop_sw_if_index);
-          if (nh_result)
-            nh_adj_index = *nh_result;
-          else
-            {
-              ip_adjacency_t * adj;
-              adj = ip_add_adjacency (lm, /* template */ 0, /* block size */ 1,
-                                      &nh_adj_index);
-              ip4_adjacency_set_interface_route (vnm, adj, next_hop_sw_if_index, /* if_address_index */ ~0);
-              ip_call_add_del_adjacency_callbacks (lm, nh_adj_index, /* is_del */ 0);
-              hash_set (im->interface_route_adj_index_by_sw_if_index, next_hop_sw_if_index, nh_adj_index);
-            }
-        }
-      else
-        {
-          nh_hash = fib->adj_index_by_dst_address[32];
-          nh_result = hash_get (nh_hash, next_hop->data_u32);
-          
-          /* Next hop must be known. */
-          if (! nh_result)
-            {
-	      ip_adjacency_t * adj;
-
-	      nh_adj_index = ip4_fib_lookup_with_table (im, fib_index,
-							next_hop, 0);
-	      adj = ip_get_adjacency (lm, nh_adj_index);
-	      /* if ARP interface adjacencty is present, we need to
-		 install ARP adjaceny for specific next hop */
-	      if (adj->lookup_next_index == IP_LOOKUP_NEXT_ARP &&
-		  adj->arp.next_hop.ip4.as_u32 == 0)
-		{
-		  nh_adj_index = vnet_arp_glean_add(fib_index, next_hop);
-		}
-	      else
-		{
-		  /* Next hop is not known, so create indirect adj */
-		  ip_adjacency_t add_adj;
-		  memset (&add_adj, 0, sizeof(add_adj));
-		  add_adj.n_adj = 1;
-		  add_adj.lookup_next_index = IP_LOOKUP_NEXT_INDIRECT;
-		  add_adj.indirect.next_hop.ip4.as_u32 = next_hop->as_u32;
-		  add_adj.explicit_fib_index = explicit_fib_index;
-		  ip_add_adjacency (lm, &add_adj, 1, &nh_adj_index);
-		}
-	    }
-	  else
-	    nh_adj_index = *nh_result;
-	}
+	nh_adj_index = ip4_route_get_next_hop_adj(im, fib_index,
+						  next_hop,
+						  next_hop_sw_if_index,
+						  explicit_fib_index);
     }
   else
     {
diff --git a/vnet/vnet/ip/ip6.h b/vnet/vnet/ip/ip6.h
index edeecdee..22d1a4fe 100644
--- a/vnet/vnet/ip/ip6.h
+++ b/vnet/vnet/ip/ip6.h
@@ -389,6 +389,14 @@ void ip6_add_del_route_next_hop (ip6_main_t * im,
 				 u32 next_hop_sw_if_index,
 				 u32 next_hop_weight, u32 adj_index,
                                  u32 explicit_fib_index);
+
+u32
+ip6_route_get_next_hop_adj (ip6_main_t * im,
+			    u32 fib_index,
+			    ip6_address_t *next_hop,
+			    u32 next_hop_sw_if_index,
+			    u32 explicit_fib_index);
+
 u32
 ip6_get_route (ip6_main_t * im,
 	       u32 fib_index_or_table_id,
diff --git a/vnet/vnet/ip/ip6_forward.c b/vnet/vnet/ip/ip6_forward.c
index ced5f562..c581a9bc 100644
--- a/vnet/vnet/ip/ip6_forward.c
+++ b/vnet/vnet/ip/ip6_forward.c
@@ -297,6 +297,91 @@ void ip6_add_del_route (ip6_main_t * im, ip6_add_del_route_args_t * a)
   }
 }
 
+u32
+ip6_route_get_next_hop_adj (ip6_main_t * im,
+			    u32 fib_index,
+			    ip6_address_t *next_hop,
+			    u32 next_hop_sw_if_index,
+			    u32 explicit_fib_index)
+{
+  ip_lookup_main_t * lm = &im->lookup_main;
+  vnet_main_t * vnm = vnet_get_main();
+  int is_interface_next_hop;
+  uword * nh_result;
+  u32 nh_adj_index;
+  ip6_fib_t * fib;
+
+  fib = vec_elt_at_index (im->fibs, fib_index);
+
+  is_interface_next_hop = ip6_address_is_zero (next_hop);
+
+  if (is_interface_next_hop)
+    {
+      nh_result = hash_get (im->interface_route_adj_index_by_sw_if_index,
+			    next_hop_sw_if_index);
+      if (nh_result)
+	  nh_adj_index = *nh_result;
+      else
+        {
+	  ip_adjacency_t * adj;
+	  adj = ip_add_adjacency (lm, /* template */ 0, /* block size */ 1,
+				  &nh_adj_index);
+	  ip6_adjacency_set_interface_route (vnm, adj,
+					     next_hop_sw_if_index, ~0);
+	  ip_call_add_del_adjacency_callbacks
+	      (lm, next_hop_sw_if_index, /* is_del */ 0);
+	  hash_set (im->interface_route_adj_index_by_sw_if_index,
+		    next_hop_sw_if_index, nh_adj_index);
+	}
+    }
+  else if (next_hop_sw_if_index == ~0)
+    {
+      /* next-hop is recursive. we always need a indirect adj
+       * for recursive paths. Any LPM we perform now will give
+       * us a valid adj, but without tracking the next-hop we
+       * have no way to keep it valid.
+       */
+      ip_adjacency_t add_adj;
+      memset (&add_adj, 0, sizeof(add_adj));
+      add_adj.n_adj = 1;
+      add_adj.lookup_next_index = IP_LOOKUP_NEXT_INDIRECT;
+      add_adj.indirect.next_hop.ip6.as_u64[0] = next_hop->as_u64[0];
+      add_adj.indirect.next_hop.ip6.as_u64[1] = next_hop->as_u64[1];
+      add_adj.explicit_fib_index = explicit_fib_index;
+      ip_add_adjacency (lm, &add_adj, 1, &nh_adj_index);
+    }
+  else
+    {
+      BVT(clib_bihash_kv) kv, value;
+
+      /* Look for the interface /128 route */
+      kv.key[0] = next_hop->as_u64[0];
+      kv.key[1] = next_hop->as_u64[1];
+      kv.key[2] = ((u64)((fib - im->fibs))<<32) | 128;
+
+      if (BV(clib_bihash_search)(&im->ip6_lookup_table, &kv, &value) < 0)
+        {
+	  ip_adjacency_t * adj;
+	  nh_adj_index = ip6_fib_lookup_with_table (im, fib_index, next_hop);
+	  adj = ip_get_adjacency (lm, nh_adj_index);
+	  /* if ND interface adjacencty is present, we need to
+	     install ND adjaceny for specific next hop */
+	  if (adj->lookup_next_index == IP_LOOKUP_NEXT_ARP &&
+	      adj->arp.next_hop.ip6.as_u64[0] == 0 &&
+	      adj->arp.next_hop.ip6.as_u64[1] == 0)
+           {
+              nh_adj_index = vnet_ip6_neighbor_glean_add(fib_index, next_hop);
+	    }
+	}
+      else
+        {
+	  nh_adj_index = value.value;
+	}
+    }
+
+  return (nh_adj_index);
+}
+
 void
 ip6_add_del_route_next_hop (ip6_main_t * im,
 			    u32 flags,
@@ -318,9 +403,7 @@ ip6_add_del_route_next_hop (ip6_main_t * im,
   ip_adjacency_t * dst_adj;
   ip_multipath_adjacency_t * old_mp, * new_mp;
   int is_del = (flags & IP6_ROUTE_FLAG_DEL) != 0;
-  int is_interface_next_hop;
   clib_error_t * error = 0;
-  uword * nh_result;
   BVT(clib_bihash_kv) kv, value;
 
   vlib_smp_unsafe_warning();
@@ -333,64 +416,12 @@ ip6_add_del_route_next_hop (ip6_main_t * im,
   fib = vec_elt_at_index (im->fibs, fib_index);
 
   /* Lookup next hop to be added or deleted. */
-  is_interface_next_hop = ip6_address_is_zero (next_hop);
   if (adj_index == (u32)~0)
     {
-      if (is_interface_next_hop)
-        {
-          nh_result = hash_get (im->interface_route_adj_index_by_sw_if_index, 
-                                next_hop_sw_if_index);
-          if (nh_result)
-            nh_adj_index = *nh_result;
-          else
-            {
-              ip_adjacency_t * adj;
-              adj = ip_add_adjacency (lm, /* template */ 0, /* block size */ 1,
-                                      &nh_adj_index);
-              ip6_adjacency_set_interface_route (vnm, adj, 
-                                                 next_hop_sw_if_index, ~0);
-              ip_call_add_del_adjacency_callbacks 
-                (lm, nh_adj_index, /* is_del */ 0);
-              hash_set (im->interface_route_adj_index_by_sw_if_index, 
-                        next_hop_sw_if_index, nh_adj_index);
-            }
-        }
-      else
-        {
-          /* Look for the interface /128 route */
-          kv.key[0] = next_hop->as_u64[0];
-          kv.key[1] = next_hop->as_u64[1];
-          kv.key[2] = ((u64)((fib - im->fibs))<<32) | 128;
-
-          if (BV(clib_bihash_search)(&im->ip6_lookup_table, &kv, &value) < 0)
-          {
-            ip_adjacency_t * adj;
-            nh_adj_index = ip6_fib_lookup_with_table (im, fib_index, next_hop);
-            adj = ip_get_adjacency (lm, nh_adj_index);
-            /* if ND interface adjacencty is present, we need to
-                             install ND adjaceny for specific next hop */
-            if (adj->lookup_next_index == IP_LOOKUP_NEXT_ARP &&
-                adj->arp.next_hop.ip6.as_u64[0] == 0 &&
-                adj->arp.next_hop.ip6.as_u64[1] == 0)
-            {
-              nh_adj_index = vnet_ip6_neighbor_glean_add(fib_index, next_hop);
-            }
-            else
-            {
-	      ip_adjacency_t add_adj;
-	      memset (&add_adj, 0, sizeof(add_adj));
-	      add_adj.n_adj = 1;
-	      add_adj.lookup_next_index = IP_LOOKUP_NEXT_INDIRECT;
-	      add_adj.indirect.next_hop.ip6.as_u64[0] = next_hop->as_u64[0];
-	      add_adj.indirect.next_hop.ip6.as_u64[1] = next_hop->as_u64[1];
-	      add_adj.explicit_fib_index = explicit_fib_index;
-	      ip_add_adjacency (lm, &add_adj, 1, &nh_adj_index);
-            }
-          }
-          else
-            nh_adj_index = value.value;
-
-        }
+      nh_adj_index = ip6_route_get_next_hop_adj(im, fib_index,
+						next_hop,
+						next_hop_sw_if_index,
+						explicit_fib_index);
     }
   else
     {
diff --git a/vpp-api-test/vat/api_format.c b/vpp-api-test/vat/api_format.c
index 6b5271dd..d4bc27bd 100644
--- a/vpp-api-test/vat/api_format.c
+++ b/vpp-api-test/vat/api_format.c
@@ -4269,7 +4269,7 @@ static int api_ip_add_del_route (vat_main_t * vam)
     unformat_input_t * i = vam->input;
     vl_api_ip_add_del_route_t *mp;
     f64 timeout;
-    u32 sw_if_index = 0, vrf_id = 0;
+    u32 sw_if_index = ~0, vrf_id = 0;
     u8 sw_if_index_set = 0;
     u8 is_ipv6 = 0;
     u8 is_local = 0, is_drop = 0;
diff --git a/vpp/vpp-api/api.c b/vpp/vpp-api/api.c
index 6041b11e..0879d49d 100644
--- a/vpp/vpp-api/api.c
+++ b/vpp/vpp-api/api.c
@@ -862,7 +862,7 @@ static int ip4_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
     uword * p;
     clib_error_t * e;
     u32 ai;
-    ip_adjacency_t *nh_adj, *add_adj = 0;
+    ip_adjacency_t *adj;
 
     p = hash_get (im->fib_index_by_table_id, ntohl(mp->vrf_id));
     if (!p) {
@@ -879,7 +879,8 @@ static int ip4_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
         fib_index = p[0];
     }
 
-    if (pool_is_free_index (vnm->interface_main.sw_interfaces,
+    if (~0 != mp->next_hop_sw_if_index &&
+	pool_is_free_index (vnm->interface_main.sw_interfaces,
                             ntohl(mp->next_hop_sw_if_index)))
         return VNET_API_ERROR_NO_MATCHING_INTERFACE;
 
@@ -887,7 +888,7 @@ static int ip4_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
             sizeof (next_hop_address.data));
 
     /* Arp for the next_hop if necessary */
-    if (mp->is_add && mp->resolve_if_needed) {
+    if (mp->is_add && mp->resolve_if_needed && ~0 != mp->next_hop_sw_if_index) {
         u32 lookup_result;
         ip_adjacency_t * adj;
 
@@ -971,50 +972,43 @@ static int ip4_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
         else if (mp->is_local)
             ai = lm->local_adj_index;
         else if (mp->is_classify) {
-            ip_adjacency_t cadj;
-            memset(&cadj, 0, sizeof(cadj));
-            cadj.lookup_next_index = IP_LOOKUP_NEXT_CLASSIFY;
-            cadj.classify.table_index = ntohl(mp->classify_table_index);
-            if (pool_is_free_index (cm->tables, cadj.classify.table_index)) {
+	    if (pool_is_free_index (cm->tables, ntohl(mp->classify_table_index))) {
                 dsunlock(sm);
                 return VNET_API_ERROR_NO_SUCH_TABLE;
             }
-            vec_add1 (add_adj, cadj);
-            goto do_add_del;
-        }
-        else {
-            ai = ip4_fib_lookup_with_table
-                (im, fib_index, &next_hop_address,
-                 1 /* disable default route */);
-            if (ai == lm->miss_adj_index) {
-                dsunlock(sm);
-                return VNET_API_ERROR_NEXT_HOP_NOT_IN_FIB;
-            }
-        }
+	    adj = ip_add_adjacency (lm,
+				    /* template */ 0,
+				    /* block size */ 1,
+				    &ai);
 
-        nh_adj = ip_get_adjacency (lm, ai);
-	if (nh_adj->lookup_next_index == IP_LOOKUP_NEXT_ARP &&
-	    nh_adj->arp.next_hop.ip4.as_u32 == 0) {
-	    /* the next-hop resovles via a glean adj. create and use
-	     * a ARP adj for the next-hop */
-	    a.adj_index = vnet_arp_glean_add(fib_index, &next_hop_address);
-	    a.add_adj = NULL;
-	    a.n_add_adj = 0;
-	    ip4_add_del_route (im, &a);
-
-	    goto done;
+            adj->lookup_next_index = IP_LOOKUP_NEXT_CLASSIFY;
+            adj->classify.table_index = ntohl(mp->classify_table_index);
 	}
-	vec_add1 (add_adj, nh_adj[0]);
-        if (mp->lookup_in_vrf) {
+        else if (mp->lookup_in_vrf) {
             p = hash_get (im->fib_index_by_table_id, ntohl(mp->lookup_in_vrf));
-            if (p)
-                add_adj[0].explicit_fib_index = p[0];
+            if (p) {
+		adj = ip_add_adjacency (lm,
+					/* template */ 0,
+					/* block size */ 1,
+					&ai);
+                adj->explicit_fib_index = p[0];
+	    }
             else {
-                vec_free (add_adj);
                 dsunlock(sm);
-                return VNET_API_ERROR_NO_SUCH_INNER_FIB;
-            }
-        }
+		return VNET_API_ERROR_NO_SUCH_INNER_FIB;
+	    }
+	}
+        else
+	    ai = ip4_route_get_next_hop_adj (im,
+					     fib_index,
+					     &next_hop_address,
+					     ntohl(mp->next_hop_sw_if_index),
+					     fib_index);
+
+	if (ai == lm->miss_adj_index) {
+	    dsunlock(sm);
+	    return VNET_API_ERROR_NO_SUCH_INNER_FIB;
+       }
     } else {
         ip_adjacency_t * adj;
         int disable_default_route = 1;
@@ -1038,15 +1032,9 @@ static int ip4_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
         }
     }
 
-do_add_del:
-    a.adj_index = ~0;
-    a.add_adj = add_adj;
-    a.n_add_adj = vec_len(add_adj);
+    a.adj_index = ai;
     ip4_add_del_route (im, &a);
 
-    vec_free (add_adj);
-
-done:
     dsunlock (sm);
     return 0;
 }
@@ -1067,7 +1055,7 @@ static int ip6_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
     u32 fib_index;
     uword * p;
     clib_error_t * e;
-    ip_adjacency_t * nh_adj, * add_adj = 0;
+    ip_adjacency_t *adj = 0;
     u32 ai;
 
     p = hash_get (im->fib_index_by_table_id, ntohl(mp->vrf_id));
@@ -1086,7 +1074,8 @@ static int ip6_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
         fib_index = p[0];
     }
 
-    if (pool_is_free_index (vnm->interface_main.sw_interfaces,
+    if (~0 != mp->next_hop_sw_if_index &&
+	pool_is_free_index (vnm->interface_main.sw_interfaces,
                             ntohl(mp->next_hop_sw_if_index)))
         return VNET_API_ERROR_NO_MATCHING_INTERFACE;
 
@@ -1094,7 +1083,7 @@ static int ip6_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
             sizeof (next_hop_address.as_u8));
 
     /* Arp for the next_hop if necessary */
-    if (mp->is_add && mp->resolve_if_needed) {
+    if (mp->is_add && mp->resolve_if_needed && ~0 != mp->next_hop_sw_if_index) {
         u32 lookup_result;
         ip_adjacency_t * adj;
 
@@ -1176,27 +1165,30 @@ static int ip6_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
             ai = lm->drop_adj_index;
         else if (mp->is_local)
             ai = lm->local_adj_index;
-        else {
-            ai = ip6_fib_lookup_with_table
-                (im, fib_index, &next_hop_address);
-            if (ai == lm->miss_adj_index) {
-                dsunlock(sm);
-                return VNET_API_ERROR_NEXT_HOP_NOT_IN_FIB;
-            }
-        }
-
-        nh_adj = ip_get_adjacency (lm, ai);
-        vec_add1 (add_adj, nh_adj[0]);
-        if (mp->lookup_in_vrf) {
+	else if (mp->lookup_in_vrf) {
             p = hash_get (im->fib_index_by_table_id, ntohl(mp->lookup_in_vrf));
-            if (p)
-                add_adj[0].explicit_fib_index = p[0];
+            if (p) {
+		adj = ip_add_adjacency (lm,
+					/* template */ 0,
+					/* block size */ 1,
+					&ai);
+                adj->explicit_fib_index = p[0];
+	    }
             else {
-                vec_free (add_adj);
-                dsunlock(sm);
+		dsunlock(sm);
                 return VNET_API_ERROR_NO_SUCH_INNER_FIB;
-            }
-        }
+	    }
+	}
+       else
+	   ai = ip6_route_get_next_hop_adj (im,
+					    fib_index,
+					    &next_hop_address,
+					    ntohl(mp->next_hop_sw_if_index),
+					    fib_index);
+      if (ai == lm->miss_adj_index) {
+	  dsunlock(sm);
+	  return VNET_API_ERROR_NEXT_HOP_NOT_IN_FIB;
+      }
     } else {
         ip_adjacency_t * adj;
 
@@ -1213,13 +1205,9 @@ static int ip6_add_del_route_t_handler (vl_api_ip_add_del_route_t *mp)
         }
     }
 
-    a.adj_index = ~0;
-    a.add_adj = add_adj;
-    a.n_add_adj = vec_len(add_adj);
+    a.adj_index = ai;
     ip6_add_del_route (im, &a);
 
-    vec_free (add_adj);
-
     dsunlock (sm);
     return 0;
 }