More LISP SD FIB and forwarding fixes

o) Avoid using explicit_fib_index in the dst (main) FIBs. It's used in
the IP6 lookup
o) use if_address_index instead of rewrite_header.node_index to store
tunnel indexes. This ensures the tunnel index is used in the signature
computation and thus avoids all complications/hacks needed to make src
adjacencies unique.
o) Fixed negative fwd entry route insertion

Change-Id: Ie56356f165b96dfa929da5672a3a429996366460
Signed-off-by: Florin Coras <fcoras@cisco.com>

3 files changed, 56 insertions, 62 deletions

diff --git a/vnet/vnet/lisp-gpe/interface.c b/vnet/vnet/lisp-gpe/interface.c
index 7537962b3bc..bda68d6ea4b 100644
--- a/vnet/vnet/lisp-gpe/interface.c
+++ b/vnet/vnet/lisp-gpe/interface.c
@@ -65,7 +65,7 @@ get_one_tunnel_inline (lisp_gpe_main_t * lgm, vlib_buffer_t * b0,
   else
     adj0 = ip_get_adjacency (lgm->lm6, adj_index0);
 
-  tunnel_index0 = adj0->rewrite_header.node_index;
+  tunnel_index0 = adj0->if_address_index;
   t0[0] = pool_elt_at_index(lgm->tunnels, tunnel_index0);
 
   ASSERT(t0[0] != 0);
@@ -114,8 +114,8 @@ get_two_tunnels_inline (lisp_gpe_main_t * lgm, vlib_buffer_t * b0,
       adj1 = ip_get_adjacency (lgm->lm6, adj_index1);
     }
 
-  tunnel_index0 = adj0->rewrite_header.node_index;
-  tunnel_index1 = adj1->rewrite_header.node_index;
+  tunnel_index0 = adj0->if_address_index;
+  tunnel_index1 = adj1->if_address_index;
 
   t0[0] = pool_elt_at_index(lgm->tunnels, tunnel_index0);
   t1[0] = pool_elt_at_index(lgm->tunnels, tunnel_index1);
diff --git a/vnet/vnet/lisp-gpe/ip_forward.c b/vnet/vnet/lisp-gpe/ip_forward.c
index fcb453c6486..9d999faa0e7 100644
--- a/vnet/vnet/lisp-gpe/ip_forward.c
+++ b/vnet/vnet/lisp-gpe/ip_forward.c
@@ -245,12 +245,16 @@ ip4_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
           /* dst adj should point to lisp gpe lookup */
           dst_adj.lookup_next_index = lgm->ip4_lookup_next_lgpe_ip4_lookup;
 
-          /* make sure we have different signatures for adj in different tables
-           * but with the same lookup_next_index */
-          dst_adj.explicit_fib_index = table_id;
-
+          /* explicit_fib_index is used in IP6 FIB lookup, don't reuse it */
+          dst_adj.explicit_fib_index = ~0;
           dst_adj.n_adj = 1;
 
+          /* make sure we have different signatures for adj in different tables
+           * but with the same lookup_next_index and for adj in the same table
+           * but associated to different destinations */
+          dst_adj.if_address_index = table_id;
+          dst_adj.indirect.next_hop.ip4 = dst;
+
           memset(&a, 0, sizeof(a));
           a.flags = IP4_ROUTE_FLAG_TABLE_ID;
           a.table_index_or_table_id = table_id; /* vrf */
@@ -267,11 +271,10 @@ ip4_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
           p = ip4_get_route (lgm->im4, table_id, 0, dst.as_u8,
                              dst_address_length);
 
-          ASSERT(p != 0);
-
           /* make sure insertion succeeded */
           if (CLIB_DEBUG)
             {
+              ASSERT(p != 0);
               dst_adjp = ip_get_adjacency (lgm->lm4, p[0]);
               ASSERT(dst_adjp->rewrite_header.sw_if_index
                       == dst_adj.rewrite_header.sw_if_index);
@@ -291,12 +294,6 @@ ip4_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
 
   dst_adjp = ip_get_adjacency (lgm->lm4, p[0]);
 
-  /* make sure adj signature is unique, i.e., fill in mcast_group_index
-   * and saved_lookup_next index with data that makes this adj unique.
-   * All these fields are (and should stay that way) unused by LISP. */
-  add_adj->mcast_group_index = table_id;
-  add_adj->saved_lookup_next_index = dst_adjp->rewrite_header.sw_if_index;
-
   /* add/del src prefix to src fib */
   memset(&a, 0, sizeof(a));
   a.flags = IP4_ROUTE_FLAG_TABLE_ID;
@@ -311,15 +308,15 @@ ip4_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
   ip4_sd_fib_add_del_src_route (lgm, &a);
 
   /* make sure insertion succeeded */
-  if (CLIB_DEBUG)
+  if (CLIB_DEBUG && is_add)
     {
       uword * sai;
       ip_adjacency_t * src_adjp;
       sai = ip4_sd_get_src_route (lgm, dst_adjp->rewrite_header.sw_if_index,
                                   &src, src_address_length);
+      ASSERT(sai != 0);
       src_adjp = ip_get_adjacency(lgm->lm4, sai[0]);
-      ASSERT(src_adjp->rewrite_header.node_index
-              == add_adj->rewrite_header.node_index);
+      ASSERT(src_adjp->if_address_index == add_adj->if_address_index);
     }
 
   /* if a delete, check if there are elements left in the src fib */
@@ -383,30 +380,23 @@ static u32
 ip6_sd_get_src_route (lisp_gpe_main_t * lgm, u32 src_fib_index,
                       ip6_address_t * src, u32 address_length)
 {
-  int i, len;
   int rv;
   BVT(clib_bihash_kv) kv, value;
   ip6_src_fib_t * fib = pool_elt_at_index (lgm->ip6_src_fibs, src_fib_index);
 
-  len = vec_len (fib->prefix_lengths_in_search_order);
+  ip6_address_t * mask;
 
-  for (i = 0; i < len; i++)
-    {
-      int dst_address_length = fib->prefix_lengths_in_search_order[i];
-      ip6_address_t * mask;
-
-      ASSERT(dst_address_length >= 0 && dst_address_length <= 128);
+  ASSERT(address_length <= 128);
 
-      mask = &fib->fib_masks[dst_address_length];
+  mask = &fib->fib_masks[address_length];
 
-      kv.key[0] = src->as_u64[0] & mask->as_u64[0];
-      kv.key[1] = src->as_u64[1] & mask->as_u64[1];
-      kv.key[2] = dst_address_length;
+  kv.key[0] = src->as_u64[0] & mask->as_u64[0];
+  kv.key[1] = src->as_u64[1] & mask->as_u64[1];
+  kv.key[2] = address_length;
 
-      rv = BV(clib_bihash_search_inline_2)(&fib->ip6_lookup_table, &kv, &value);
-      if (rv == 0)
-        return value.value;
-    }
+  rv = BV(clib_bihash_search_inline_2)(&fib->ip6_lookup_table, &kv, &value);
+  if (rv == 0)
+    return value.value;
 
   return 0;
 }
@@ -577,7 +567,6 @@ ip6_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
       /* insert dst prefix to ip6 fib, if it's not in yet */
       if (adj_index == 0)
         {
-
           /* allocate and init src ip6 fib */
           pool_get(lgm->ip6_src_fibs, src_fib);
           memset(src_fib, 0, sizeof(src_fib[0]));
@@ -591,9 +580,15 @@ ip6_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
           /* dst adj should point to lisp gpe ip lookup */
           dst_adj.lookup_next_index = lgm->ip6_lookup_next_lgpe_ip6_lookup;
 
+          /* explicit_fib_index is used in IP6 FIB lookup, don't reuse it */
+          dst_adj.explicit_fib_index = ~0;
+          dst_adj.n_adj = 1;
+
           /* make sure we have different signatures for adj in different tables
-           * but with the same lookup_next_index */
-          dst_adj.explicit_fib_index = table_id;
+           * but with the same lookup_next_index and for adj in the same table
+           * but associated to different destinations */
+          dst_adj.if_address_index = table_id;
+          dst_adj.indirect.next_hop.ip6 = dst;
 
           memset(&a, 0, sizeof(a));
           a.flags = IP6_ROUTE_FLAG_TABLE_ID;
@@ -611,11 +606,10 @@ ip6_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
           adj_index = ip6_get_route (lgm->im6, table_id, 0, &dst,
                                      dst_address_length);
 
-          ASSERT(adj_index != 0);
-
           /* make sure insertion succeeded */
           if (CLIB_DEBUG)
             {
+              ASSERT(adj_index != 0);
               dst_adjp = ip_get_adjacency (lgm->lm6, adj_index);
               ASSERT(dst_adjp->rewrite_header.sw_if_index
                       == dst_adj.rewrite_header.sw_if_index);
@@ -627,20 +621,13 @@ ip6_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
       if (adj_index == 0)
         {
           clib_warning("Trying to delete inexistent dst route for %U. Aborting",
-                       format_ip6_address_and_length, dst.as_u8,
-                       dst_address_length);
+                       format_ip_prefix, dst_prefix);
           return -1;
         }
     }
 
   dst_adjp = ip_get_adjacency (lgm->lm6, adj_index);
 
-  /* make sure adj signature is unique, i.e., fill in mcast_group_index
-   * and saved_lookup_next index with data that makes this adj unique.
-   * All these fields are (and should stay that way) unused by LISP. */
-  add_adj->mcast_group_index = table_id;
-  add_adj->saved_lookup_next_index = dst_adjp->rewrite_header.sw_if_index;
-
   /* add/del src prefix to src fib */
   memset(&a, 0, sizeof(a));
   a.flags = IP6_ROUTE_FLAG_TABLE_ID;
@@ -655,15 +642,15 @@ ip6_sd_fib_add_del_route (lisp_gpe_main_t * lgm, ip_prefix_t * dst_prefix,
   ip6_sd_fib_add_del_src_route (lgm, &a);
 
   /* make sure insertion succeeded */
-  if (CLIB_DEBUG)
+  if (CLIB_DEBUG && is_add)
     {
       u32 sai;
       ip_adjacency_t * src_adjp;
       sai = ip6_sd_get_src_route (lgm, dst_adjp->rewrite_header.sw_if_index,
                                   &src, src_address_length);
+      ASSERT(sai != 0);
       src_adjp = ip_get_adjacency(lgm->lm6, sai);
-      ASSERT(src_adjp->rewrite_header.node_index
-              == add_adj->rewrite_header.node_index);
+      ASSERT(src_adjp->if_address_index == add_adj->if_address_index);
     }
 
   /* if a delete, check if there are elements left in the src fib */
diff --git a/vnet/vnet/lisp-gpe/lisp_gpe.c b/vnet/vnet/lisp-gpe/lisp_gpe.c
index c11824e6315..c4f936eccda 100644
--- a/vnet/vnet/lisp-gpe/lisp_gpe.c
+++ b/vnet/vnet/lisp-gpe/lisp_gpe.c
@@ -179,13 +179,20 @@ add_del_negative_fwd_entry (lisp_gpe_main_t * lgm,
                             vnet_lisp_gpe_add_del_fwd_entry_args_t * a)
 {
   ip_adjacency_t adj;
+  ip_prefix_t * dpref = &gid_address_ippref(&a->deid);
+  ip_prefix_t * spref = &gid_address_ippref(&a->seid);
+
   /* setup adjacency for eid */
   memset (&adj, 0, sizeof(adj));
   adj.n_adj = 1;
-  adj.explicit_fib_index = ~0;
 
-  ip_prefix_t * dpref = &gid_address_ippref(&a->deid);
-  ip_prefix_t * spref = &gid_address_ippref(&a->seid);
+  /* fill in 'legal' data to avoid issues */
+  adj.lookup_next_index =  (ip_prefix_version(dpref) == IP4) ?
+                                  lgm->ip4_lookup_next_lgpe_ip4_lookup :
+                                  lgm->ip6_lookup_next_lgpe_ip6_lookup;
+
+  adj.rewrite_header.sw_if_index = ~0;
+  adj.rewrite_header.next_index = ~0;
 
   switch (a->action)
     {
@@ -196,16 +203,15 @@ add_del_negative_fwd_entry (lisp_gpe_main_t * lgm,
        * more specific for the eid with the next-hop found */
     case SEND_MAP_REQUEST:
       /* insert tunnel that always sends map-request */
-      adj.rewrite_header.sw_if_index = ~0;
-      adj.lookup_next_index = (u32) (ip_prefix_version(dpref) == IP4) ?
-                                     LGPE_IP4_LOOKUP_NEXT_LISP_CP_LOOKUP:
-                                     LGPE_IP6_LOOKUP_NEXT_LISP_CP_LOOKUP;
+      adj.explicit_fib_index = (ip_prefix_version(dpref) == IP4) ?
+                               LGPE_IP4_LOOKUP_NEXT_LISP_CP_LOOKUP:
+                               LGPE_IP6_LOOKUP_NEXT_LISP_CP_LOOKUP;
       /* add/delete route for prefix */
       return ip_sd_fib_add_del_route (lgm, dpref, spref, a->table_id, &adj,
                                       a->is_add);
     case DROP:
       /* for drop fwd entries, just add route, no need to add encap tunnel */
-      adj.lookup_next_index =  (u32) (ip_prefix_version(dpref) == IP4 ?
+      adj.explicit_fib_index =  (ip_prefix_version(dpref) == IP4 ?
               LGPE_IP4_LOOKUP_NEXT_DROP : LGPE_IP6_LOOKUP_NEXT_DROP);
 
       /* add/delete route for prefix */
@@ -259,7 +265,7 @@ vnet_lisp_gpe_add_del_fwd_entry (vnet_lisp_gpe_add_del_fwd_entry_args_t * a,
     {
       /* send packets that hit this adj to lisp-gpe interface output node in
        * requested vrf. */
-      lnip = ip_ver == IP4 ?
+      lnip = (ip_ver == IP4) ?
               lgm->lgpe_ip4_lookup_next_index_by_table_id :
               lgm->lgpe_ip6_lookup_next_index_by_table_id;
       lookup_next_index = hash_get(lnip, a->table_id);
@@ -271,9 +277,10 @@ vnet_lisp_gpe_add_del_fwd_entry (vnet_lisp_gpe_add_del_fwd_entry_args_t * a,
       ASSERT(lookup_next_index != 0);
       ASSERT(lgpe_sw_if_index != 0);
 
-      /* hijack explicit fib index to store lisp interface node index */
+      /* hijack explicit fib index to store lisp interface node index and
+       * if_address_index for the tunnel index */
       adj.explicit_fib_index = lookup_next_index[0];
-      adj.rewrite_header.node_index = tun_index;
+      adj.if_address_index = tun_index;
       adj.rewrite_header.sw_if_index = lgpe_sw_if_index[0];
     }
 
@@ -291,7 +298,7 @@ vnet_lisp_gpe_add_del_fwd_entry (vnet_lisp_gpe_add_del_fwd_entry_args_t * a,
                                adj_index);
 
       ASSERT(adjp != 0);
-      ASSERT(adjp->rewrite_header.node_index == tun_index);
+      ASSERT(adjp->if_address_index == tun_index);
     }
 
   return rv;