MPLS Mcast

 1 - interface-DPO
        Used in the Data-plane to change a packet's input interface
 2 - MPLS multicast FIB entry
        Same as a unicast entry but it links to a replicate not a load-balance DPO
 3 - Multicast MPLS tunnel
        Update MPLS tunnels to use a FIB path-list to describe the endpoint[s]. Use the path-list to generate the forwarding chain (DPOs) to link to .
 4 - Resolve a path via a local label (of an mLDP LSP)
        For IP multicast entries to use an LSP in the replication list, we need to decribe the 'resolve-via-label' where the label is that of a multicast LSP.
 5 - MPLS disposition path sets RPF-ID
        For a interface-less LSP (i.e. mLDP not RSVP-TE) at the tail of the LSP we still need to perform an RPF check. An MPLS disposition DPO performs the MPLS pop validation checks and sets the RPF-ID in the packet.
 6 - RPF check with per-entry RPF-ID
       An RPF-ID is used instead of a real interface SW if index in the case the IP traffic arrives from an LSP that does not have an associated interface.

Change-Id: Ib92e177be919147bafeb599729abf3d1abc2f4b3
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 40 insertions, 7 deletions

diff --git a/src/vnet/fib/fib_entry.c b/src/vnet/fib/fib_entry.c
index dac1fce995f..6f811aa1414 100644
--- a/src/vnet/fib/fib_entry.c
+++ b/src/vnet/fib/fib_entry.c
@@ -75,13 +75,7 @@ fib_entry_get_default_chain_type (const fib_entry_t *fib_entry)
 	return (FIB_FORW_CHAIN_TYPE_UNICAST_IP6);
     case FIB_PROTOCOL_MPLS:
 	if (MPLS_EOS == fib_entry->fe_prefix.fp_eos)
-	    /*
-	     * 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(
-			fib_entry->fe_prefix.fp_payload_proto));
+	    return (FIB_FORW_CHAIN_TYPE_MPLS_EOS);
 	else
 	    return (FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS);
     }
@@ -371,6 +365,35 @@ fib_entry_contribute_urpf (fib_node_index_t entry_index,
 }
 
 /*
+ * If the client is request a chain for multicast forwarding then swap
+ * the chain type to one that can provide such transport.
+ */
+static fib_forward_chain_type_t
+fib_entry_chain_type_mcast_to_ucast (fib_forward_chain_type_t fct)
+{
+    switch (fct)
+    {
+    case FIB_FORW_CHAIN_TYPE_MCAST_IP4:
+    case FIB_FORW_CHAIN_TYPE_MCAST_IP6:
+        /*
+         * we can only transport IP multicast packets if there is an
+         * LSP.
+         */
+        fct = FIB_FORW_CHAIN_TYPE_MPLS_EOS;
+        break;
+    case FIB_FORW_CHAIN_TYPE_MPLS_EOS:
+    case FIB_FORW_CHAIN_TYPE_UNICAST_IP4:
+    case FIB_FORW_CHAIN_TYPE_UNICAST_IP6:
+    case FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS:
+    case FIB_FORW_CHAIN_TYPE_ETHERNET:
+    case FIB_FORW_CHAIN_TYPE_NSH:
+        break;
+    }
+
+    return (fct);
+}
+
+/*
  * fib_entry_contribute_forwarding
  *
  * Get an lock the forwarding information (DPO) contributed by the FIB entry.
@@ -385,6 +408,11 @@ fib_entry_contribute_forwarding (fib_node_index_t fib_entry_index,
 
     fib_entry = fib_entry_get(fib_entry_index);
 
+    /*
+     * mfib children ask for mcast chains. fix these to the appropriate ucast types.
+     */
+    fct = fib_entry_chain_type_mcast_to_ucast(fct);
+
     if (fct == fib_entry_get_default_chain_type(fib_entry))
     {
         dpo_copy(dpo, &fib_entry->fe_lb);
@@ -414,6 +442,11 @@ fib_entry_contribute_forwarding (fib_node_index_t fib_entry_index,
 
         dpo_copy(dpo, &fed->fd_dpo);
     }
+    /*
+     * don't allow the special index indicating replicate.vs.load-balance
+     * to escape to the clients
+     */
+    dpo->dpoi_index &= ~MPLS_IS_REPLICATE;
 }
 
 const dpo_id_t *