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, 6 insertions, 0 deletions

diff --git a/vnet/vnet/replication.c b/vnet/vnet/replication.c
index 571be7d807c..561c86cdfa4 100644
--- a/vnet/vnet/replication.c
+++ b/vnet/vnet/replication.c
@@ -225,6 +225,12 @@ replication_recycle_callback (vlib_main_t * vm, vlib_buffer_free_list_t * fl)
 	  /* Mark that this buffer was just recycled */
 	  b0->flags |= VLIB_BUFFER_IS_RECYCLED;
 
+#if (CLIB_DEBUG > 0)
+#if DPDK == 0
+	  vlib_buffer_set_known_state (vm, bi0, VLIB_BUFFER_KNOWN_ALLOCATED);
+#endif
+#endif
+
 	  /* If buffer is traced, mark frame as traced */
 	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 	    f->flags |= VLIB_FRAME_TRACE;