fib: MPLS EOS chains built for attached prefixes should link to a lookup DPO

Type: fix

Presently a local label associated with an attached or connected prefix will link to the glean. This is a problem since it will never use the adj-fibs that are installed for that attached prefix. Instead link the local label to a lookup in the table in which the attached link is bound.

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: Iad49fb6168b9ba47216a9a52bd262363b49c3c43

10 files changed, 84 insertions, 66 deletions

diff --git a/src/vnet/fib/fib_entry_src.c b/src/vnet/fib/fib_entry_src.c
index 5e66de7c93b..c0275e898bd 100644
--- a/src/vnet/fib/fib_entry_src.c
+++ b/src/vnet/fib/fib_entry_src.c
@@ -257,6 +257,7 @@ typedef struct fib_entry_src_collect_forwarding_ctx_t_
     fib_forward_chain_type_t fct;
     int n_recursive_constrained;
     u16 preference;
+    dpo_proto_t payload_proto;
 } fib_entry_src_collect_forwarding_ctx_t;
 
 /**
@@ -289,47 +290,6 @@ fib_entry_src_valid_out_label (mpls_label_t label)
              MPLS_IETF_IMPLICIT_NULL_LABEL == label));
 }
 
-/**
- * @brief Turn the chain type requested by the client into the one they
- * really wanted
- */
-fib_forward_chain_type_t
-fib_entry_chain_type_fixup (const fib_entry_t *entry,
-			    fib_forward_chain_type_t fct)
-{
-    /*
-     * The EOS chain is a tricky since one cannot know the adjacency
-     * to link to without knowing what the packets payload protocol
-     * will be once the label is popped.
-     */
-    fib_forward_chain_type_t dfct;
-
-    if (FIB_FORW_CHAIN_TYPE_MPLS_EOS != fct)
-    {
-        return (fct);
-    }
-
-    dfct = fib_entry_get_default_chain_type(entry);
-
-    if (FIB_FORW_CHAIN_TYPE_MPLS_EOS == dfct)
-    {
-        /*
-         * If the entry being asked is a eos-MPLS label entry,
-         * then use the payload-protocol field, that we stashed there
-         * for just this purpose
-         */
-        return (fib_forw_chain_type_from_dpo_proto(
-                    entry->fe_prefix.fp_payload_proto));
-    }
-    /*
-     * else give them what this entry would be by default. i.e. if it's a v6
-     * entry, then the label its local labelled should be carrying v6 traffic.
-     * If it's a non-EOS label entry, then there are more labels and we want
-     * a non-eos chain.
-     */
-    return (dfct);
-}
-
 static dpo_proto_t
 fib_prefix_get_payload_proto (const fib_prefix_t *pfx)
 {
@@ -371,7 +331,8 @@ fib_entry_src_get_path_forwarding (fib_node_index_t path_index,
 
         nh->path_index = path_index;
         nh->path_weight = fib_path_get_weight(path_index);
-        fib_path_contribute_forwarding(path_index, ctx->fct, &nh->path_dpo);
+        fib_path_contribute_forwarding(path_index, ctx->fct,
+                                       ctx->payload_proto, &nh->path_dpo);
 
         break;
     case FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS:
@@ -384,6 +345,7 @@ fib_entry_src_get_path_forwarding (fib_node_index_t path_index,
             nh->path_weight = fib_path_get_weight(path_index);
             fib_path_contribute_forwarding(path_index,
                                            FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS,
+                                           ctx->payload_proto,
                                            &nh->path_dpo);
         }
         break;
@@ -397,11 +359,11 @@ fib_entry_src_get_path_forwarding (fib_node_index_t path_index,
             nh->path_index = path_index;
             nh->path_weight = fib_path_get_weight(path_index);
             fib_path_contribute_forwarding(path_index,
-                                           fib_entry_chain_type_fixup(ctx->fib_entry,
-                                                                      ctx->fct),
+                                           ctx->fct,
+                                           ctx->payload_proto,
                                            &nh->path_dpo);
             fib_path_stack_mpls_disp(path_index,
-                                     fib_prefix_get_payload_proto(&ctx->fib_entry->fe_prefix),
+                                     ctx->payload_proto,
                                      FIB_MPLS_LSP_MODE_PIPE,
                                      &nh->path_dpo);
 
@@ -480,9 +442,8 @@ fib_entry_src_collect_forwarding (fib_node_index_t pl_index,
                  */
                 ctx->next_hops =
                     fib_path_ext_stack(path_ext,
+                                       ctx->payload_proto,
                                        ctx->fct,
-                                       fib_entry_chain_type_fixup(ctx->fib_entry,
-                                                                  ctx->fct),
                                        ctx->next_hops);
             }
             else
@@ -609,6 +570,7 @@ fib_entry_src_mk_lb (fib_entry_t *fib_entry,
         .preference = 0xffff,
         .start_source_index = start,
         .end_source_index = end,
+        .payload_proto = fib_prefix_get_payload_proto(&fib_entry->fe_prefix),
     };
 
     /*
diff --git a/src/vnet/fib/fib_entry_src.h b/src/vnet/fib/fib_entry_src.h
index ced6b5c42fc..1f348baeacb 100644
--- a/src/vnet/fib/fib_entry_src.h
+++ b/src/vnet/fib/fib_entry_src.h
@@ -326,9 +326,6 @@ extern fib_entry_flag_t fib_entry_get_flags_i(const fib_entry_t *fib_entry);
 extern fib_path_list_flags_t fib_entry_src_flags_2_path_list_flags(
     fib_entry_flag_t eflags);
 
-extern fib_forward_chain_type_t fib_entry_chain_type_fixup(const fib_entry_t *entry,
-                                                           fib_forward_chain_type_t fct);
-
 extern void fib_entry_src_mk_lb (fib_entry_t *fib_entry,
 				 fib_source_t source,
 				 fib_forward_chain_type_t fct,
diff --git a/src/vnet/fib/fib_path.c b/src/vnet/fib/fib_path.c
index d7b6091325b..e4ad8770449 100644
--- a/src/vnet/fib/fib_path.c
+++ b/src/vnet/fib/fib_path.c
@@ -2421,6 +2421,7 @@ fib_path_stack_mpls_disp (fib_node_index_t path_index,
 void
 fib_path_contribute_forwarding (fib_node_index_t path_index,
 				fib_forward_chain_type_t fct,
+                                dpo_proto_t payload_proto,
 				dpo_id_t *dpo)
 {
     fib_path_t *path;
@@ -2428,7 +2429,6 @@ fib_path_contribute_forwarding (fib_node_index_t path_index,
     path = fib_path_get(path_index);
 
     ASSERT(path);
-    ASSERT(FIB_FORW_CHAIN_TYPE_MPLS_EOS != fct);
 
     /*
      * The DPO stored in the path was created when the path was resolved.
@@ -2446,9 +2446,19 @@ fib_path_contribute_forwarding (fib_node_index_t path_index,
 	case FIB_PATH_TYPE_ATTACHED_NEXT_HOP:
 	    switch (fct)
 	    {
+	    case FIB_FORW_CHAIN_TYPE_MPLS_EOS: {
+                    dpo_id_t tmp = DPO_INVALID;
+                    dpo_copy (&tmp, dpo);
+                    path = fib_path_attached_next_hop_get_adj(
+                           path,
+                           dpo_proto_to_link(payload_proto),
+                           &tmp);
+                    dpo_copy (dpo, &tmp);
+                    dpo_reset(&tmp);
+                    break;
+            }
 	    case FIB_FORW_CHAIN_TYPE_UNICAST_IP4:
 	    case FIB_FORW_CHAIN_TYPE_UNICAST_IP6:
-	    case FIB_FORW_CHAIN_TYPE_MPLS_EOS:
 	    case FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS:
 	    case FIB_FORW_CHAIN_TYPE_ETHERNET:
 	    case FIB_FORW_CHAIN_TYPE_NSH:
@@ -2560,10 +2570,25 @@ fib_path_contribute_forwarding (fib_node_index_t path_index,
         case FIB_PATH_TYPE_ATTACHED:
 	    switch (fct)
 	    {
+	    case FIB_FORW_CHAIN_TYPE_MPLS_EOS:
+                /*
+                 * End of stack traffic via an attacehd path (a glean)
+                 * must forace an IP lookup so that the IP packet can
+                 * match against any installed adj-fibs
+                 */
+                lookup_dpo_add_or_lock_w_fib_index(
+                    fib_table_get_index_for_sw_if_index(
+                        dpo_proto_to_fib(payload_proto),
+                        path->attached.fp_interface),
+                    payload_proto,
+                    LOOKUP_UNICAST,
+                    LOOKUP_INPUT_DST_ADDR,
+                    LOOKUP_TABLE_FROM_CONFIG,
+                    dpo);
+                break;
 	    case FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS:
 	    case FIB_FORW_CHAIN_TYPE_UNICAST_IP4:
 	    case FIB_FORW_CHAIN_TYPE_UNICAST_IP6:
-	    case FIB_FORW_CHAIN_TYPE_MPLS_EOS:
 	    case FIB_FORW_CHAIN_TYPE_ETHERNET:
 	    case FIB_FORW_CHAIN_TYPE_NSH:
             case FIB_FORW_CHAIN_TYPE_BIER:
@@ -2609,8 +2634,8 @@ fib_path_contribute_forwarding (fib_node_index_t path_index,
             /*
              * Create the adj needed for sending IP multicast traffic
              */
-            interface_rx_dpo_add_or_lock(fib_forw_chain_type_to_dpo_proto(fct),
-                                         path->attached.fp_interface,
+            interface_rx_dpo_add_or_lock(payload_proto,
+                                         path->intf_rx.fp_interface,
                                          dpo);
             break;
         case FIB_PATH_TYPE_UDP_ENCAP:
@@ -2630,6 +2655,7 @@ fib_path_contribute_forwarding (fib_node_index_t path_index,
 load_balance_path_t *
 fib_path_append_nh_for_multipath_hash (fib_node_index_t path_index,
 				       fib_forward_chain_type_t fct,
+                                       dpo_proto_t payload_proto,
 				       load_balance_path_t *hash_key)
 {
     load_balance_path_t *mnh;
@@ -2646,7 +2672,7 @@ fib_path_append_nh_for_multipath_hash (fib_node_index_t path_index,
 
     if (fib_path_is_resolved(path_index))
     {
-        fib_path_contribute_forwarding(path_index, fct, &mnh->path_dpo);
+        fib_path_contribute_forwarding(path_index, fct, payload_proto, &mnh->path_dpo);
     }
     else
     {
diff --git a/src/vnet/fib/fib_path.h b/src/vnet/fib/fib_path.h
index c0f76411390..f3442c23dd6 100644
--- a/src/vnet/fib/fib_path.h
+++ b/src/vnet/fib/fib_path.h
@@ -191,6 +191,7 @@ extern uword fib_path_hash(fib_node_index_t path_index);
 extern load_balance_path_t * fib_path_append_nh_for_multipath_hash(
     fib_node_index_t path_index,
     fib_forward_chain_type_t fct,
+    dpo_proto_t payload_proto,
     load_balance_path_t *hash_key);
 extern void fib_path_stack_mpls_disp(fib_node_index_t path_index,
                                      dpo_proto_t payload_proto,
@@ -198,6 +199,7 @@ extern void fib_path_stack_mpls_disp(fib_node_index_t path_index,
                                      dpo_id_t *dpo);
 extern void fib_path_contribute_forwarding(fib_node_index_t path_index,
 					   fib_forward_chain_type_t type,
+                                           dpo_proto_t payload_proto,
 					   dpo_id_t *dpo);
 extern void fib_path_contribute_urpf(fib_node_index_t path_index,
 				     index_t urpf);
diff --git a/src/vnet/fib/fib_path_ext.c b/src/vnet/fib/fib_path_ext.c
index 209b6273a85..f5611f92271 100644
--- a/src/vnet/fib/fib_path_ext.c
+++ b/src/vnet/fib/fib_path_ext.c
@@ -163,8 +163,8 @@ fib_path_ext_mpls_flags_to_mpls_label (fib_path_ext_mpls_flags_t fpe_flags)
 
 load_balance_path_t *
 fib_path_ext_stack (fib_path_ext_t *path_ext,
+                    dpo_proto_t payload_proto,
                     fib_forward_chain_type_t child_fct,
-                    fib_forward_chain_type_t imp_null_fct,
 		    load_balance_path_t *nhs)
 {
     fib_forward_chain_type_t parent_fct;
@@ -189,7 +189,7 @@ fib_path_ext_stack (fib_path_ext_t *path_ext,
 	 */
 	if (fib_path_ext_is_imp_null(path_ext))
 	{
-            parent_fct = imp_null_fct;
+            parent_fct = fib_forw_chain_type_from_dpo_proto(payload_proto);
         }
         else
         {
@@ -240,6 +240,7 @@ fib_path_ext_stack (fib_path_ext_t *path_ext,
      */
     fib_path_contribute_forwarding(path_ext->fpe_path_index,
 				   parent_fct,
+                                   payload_proto,
 				   &via_dpo);
 
     if (dpo_is_drop(&via_dpo) ||
diff --git a/src/vnet/fib/fib_path_ext.h b/src/vnet/fib/fib_path_ext.h
index b49fd977a20..2850a588608 100644
--- a/src/vnet/fib/fib_path_ext.h
+++ b/src/vnet/fib/fib_path_ext.h
@@ -141,8 +141,8 @@ extern void fib_path_ext_resolve(fib_path_ext_t *path_ext,
 				 fib_node_index_t path_list_index);
 
 extern load_balance_path_t *fib_path_ext_stack(fib_path_ext_t *path_ext,
+                                               dpo_proto_t payload_proto,
                                                fib_forward_chain_type_t fct,
-                                               fib_forward_chain_type_t imp_null_fct,
                                                load_balance_path_t *nhs);
 
 extern fib_path_ext_t * fib_path_ext_list_push_back (fib_path_ext_list_t *list,
diff --git a/src/vnet/fib/fib_path_list.c b/src/vnet/fib/fib_path_list.c
index 81751695f47..d7e860ecb8c 100644
--- a/src/vnet/fib/fib_path_list.c
+++ b/src/vnet/fib/fib_path_list.c
@@ -378,8 +378,10 @@ fib_path_list_mk_lb (fib_path_list_t *path_list,
         if ((flags & FIB_PATH_LIST_FWD_FLAG_STICKY) ||
             fib_path_is_resolved(*path_index))
         {
-            nhs = fib_path_append_nh_for_multipath_hash(*path_index,
-                                                        fct, nhs);
+            nhs = fib_path_append_nh_for_multipath_hash(
+                *path_index, fct,
+                fib_forw_chain_type_to_dpo_proto(fct),
+                nhs);
         }
     }
 
diff --git a/src/vnet/mfib/mfib_entry.c b/src/vnet/mfib/mfib_entry.c
index 1b685d68482..8050882d436 100644
--- a/src/vnet/mfib/mfib_entry.c
+++ b/src/vnet/mfib/mfib_entry.c
@@ -547,6 +547,7 @@ typedef struct mfib_entry_collect_forwarding_ctx_t_
     load_balance_path_t * next_hops;
     fib_forward_chain_type_t fct;
     mfib_entry_src_t *msrc;
+    dpo_proto_t payload_proto;
 } mfib_entry_collect_forwarding_ctx_t;
 
 static fib_path_list_walk_rc_t
@@ -592,7 +593,8 @@ mfib_entry_src_collect_forwarding (fib_node_index_t pl_index,
 
         nh->path_index = path_index;
         nh->path_weight = fib_path_get_weight(path_index);
-        fib_path_contribute_forwarding(path_index, ctx->fct, &nh->path_dpo);
+        fib_path_contribute_forwarding(path_index, ctx->fct,
+                                       ctx->payload_proto, &nh->path_dpo);
         break;
 
     case FIB_FORW_CHAIN_TYPE_UNICAST_IP4:
@@ -632,6 +634,7 @@ mfib_entry_stack (mfib_entry_t *mfib_entry,
             .next_hops = NULL,
             .fct = mfib_entry_get_default_chain_type(mfib_entry),
             .msrc = msrc,
+            .payload_proto = fib_proto_to_dpo(mfib_entry->mfe_prefix.fp_proto),
         };
 
         /*
diff --git a/src/vnet/mpls/mpls_tunnel.c b/src/vnet/mpls/mpls_tunnel.c
index 4715958e99c..5f7bf8c3b25 100644
--- a/src/vnet/mpls/mpls_tunnel.c
+++ b/src/vnet/mpls/mpls_tunnel.c
@@ -265,10 +265,8 @@ mpls_tunnel_collect_forwarding (fib_node_index_t pl_index,
      * found a matching extension. stack it to obtain the forwarding
      * info for this path.
      */
-    ctx->next_hops = fib_path_ext_stack(path_ext,
-                                        ctx->fct,
-                                        ctx->fct,
-                                        ctx->next_hops);
+    ctx->next_hops =
+      fib_path_ext_stack (path_ext, DPO_PROTO_MPLS, ctx->fct, ctx->next_hops);
 
     return (FIB_PATH_LIST_WALK_CONTINUE);
 }
diff --git a/test/test_mpls.py b/test/test_mpls.py
index 2b959e48fb6..34645a9fce1 100644
--- a/test/test_mpls.py
+++ b/test/test_mpls.py
@@ -1563,6 +1563,33 @@ class TestMPLS(VppTestCase):
                                           VppMplsLabel(32),
                                           VppMplsLabel(99)])
 
+    def test_attached(self):
+        """ Attach Routes with Local Label """
+
+        #
+        # test that if a local label is associated with an attached/connected
+        # prefix, that we can reach hosts in the prefix.
+        #
+        binding = VppMplsIpBind(self, 44,
+                                self.pg0._local_ip4_subnet,
+                                self.pg0.local_ip4_prefix_len)
+        binding.add_vpp_config()
+
+        tx = (Ether(src=self.pg1.remote_mac,
+                    dst=self.pg1.local_mac) /
+              MPLS(label=44, ttl=64) /
+              IP(src=self.pg0.remote_ip4, dst=self.pg0.remote_ip4) /
+              UDP(sport=1234, dport=1234) /
+              Raw(b'\xa5' * 100))
+        rxs = self.send_and_expect(self.pg0, [tx], self.pg0)
+        for rx in rxs:
+            # if there's an ARP then the label is linked to the glean
+            # which is wrong.
+            self.assertFalse(rx.haslayer(ARP))
+            # it should be unicasted to the host
+            self.assertEqual(rx[Ether].dst, self.pg0.remote_mac)
+            self.assertEqual(rx[IP].dst, self.pg0.remote_ip4)
+
 
 class TestMPLSDisabled(VppTestCase):
     """ MPLS disabled """