FIB2.0: Adjacency complete pull model (VPP-487)

Change the adjacency completion model to pull not push.

A complete adjacency has a rewirte string, an incomplete one does not. the re-write string for a peer comes either from a discovery protocol (i.e. ARP/ND) or can be directly derived from the link type (i.e. GRE tunnels). Which method it is, is interface type specific.
For each packet type sent on a link to a peer there is a corresponding adjacency. For example, if there is a peer 10.0.0.1 on Eth0 and we need to send to it IPv4 and MPLS packets, there will be two adjacencies; one for the IPv4 and one for the MPLS packets. The adjacencies are thus distinguished by the packets the carry, this is known as the adjacency's 'link-type'. It is not an L3 packet type, since the adjacency can have a link type of Ethernet (for L2 over GRE).
The discovery protocols are not aware of all the link types required - only the FIB is. the FIB will create adjacencies as and when they are required, and it is thus then desirable to 'pull' from the discovery protocol the re-write required. The alternative (that we have now) is that the discovery protocol pushes (i.e. creates) adjacencies for each link type - this creates more adjacencies than we need.
To pull, FIB now requests from the interface-type to 'complete' the adjacency. The interface can then delegate to the discovery protocol (on ethernet links) or directly build the re-write (i.e on GRE).

Change-Id: I61451789ae03f26b1012d8d6524007b769b6c6ee
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 16 insertions, 10 deletions

diff --git a/vnet/vnet/adj/adj_internal.h b/vnet/vnet/adj/adj_internal.h
index 25a477ad007..f882bff84c0 100644
--- a/vnet/vnet/adj/adj_internal.h
+++ b/vnet/vnet/adj/adj_internal.h
@@ -41,21 +41,21 @@
 #define ADJ_DBG(_e, _fmt, _args...)
 #endif
 
-static inline vlib_node_registration_t*
+static inline u32
 adj_get_rewrite_node (fib_link_t linkt)
 {
     switch (linkt) {
     case FIB_LINK_IP4:
-	return (&ip4_rewrite_node);
+	return (ip4_rewrite_node.index);
     case FIB_LINK_IP6:
-	return (&ip6_rewrite_node);
+	return (ip6_rewrite_node.index);
     case FIB_LINK_MPLS:
-	return (&mpls_output_node);
+	return (mpls_output_node.index);
     case FIB_LINK_ETHERNET:
-	return (&adj_l2_rewrite_node);
+	return (adj_l2_rewrite_node.index);
     }
     ASSERT(0);
-    return (NULL);
+    return (0);
 }
 
 static inline vnet_l3_packet_type_t
@@ -75,17 +75,17 @@ adj_fib_link_2_vnet (fib_link_t linkt)
     return (0);
 }
 
-static inline vnet_l3_packet_type_t
+static inline vnet_link_t
 adj_fib_proto_2_nd (fib_protocol_t fp)
 {
     switch (fp)
     {
     case FIB_PROTOCOL_IP4:
-	return (VNET_L3_PACKET_TYPE_ARP);
+	return (VNET_LINK_ARP);
     case FIB_PROTOCOL_IP6:
-	return (VNET_L3_PACKET_TYPE_IP6);
+	return (VNET_LINK_IP6);
     case FIB_PROTOCOL_MPLS:
-	return (VNET_L3_PACKET_TYPE_MPLS_UNICAST);
+	return (VNET_LINK_MPLS);
     }
     return (0);
 }
@@ -100,6 +100,12 @@ adj_get_index (ip_adjacency_t *adj)
     return (adj - adj_pool);
 }
 
+extern void adj_nbr_update_rewrite_internal (ip_adjacency_t *adj,
+					     adj_nbr_rewrite_flag_t flags,
+					     u32 complete_next_index,
+					     u32 next_index,
+					     u8 *rewrite);
+
 extern ip_adjacency_t * adj_alloc(fib_protocol_t proto);
 
 extern void adj_nbr_remove(fib_protocol_t nh_proto,