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, 3 insertions, 1 deletions

diff --git a/vpp/vpp-api/api.c b/vpp/vpp-api/api.c
index ca56ab24480..b0e0412b127 100644
--- a/vpp/vpp-api/api.c
+++ b/vpp/vpp-api/api.c
@@ -3211,7 +3211,9 @@ dhcp_compl_event_callback (u32 client_index, u32 pid, u8 * hostname,
   mp->hostname[vec_len (hostname) + 1] = '\n';
   clib_memcpy (&mp->host_address[0], host_address, 16);
   clib_memcpy (&mp->router_address[0], router_address, 16);
-  clib_memcpy (&mp->host_mac[0], host_mac, 6);
+
+  if (NULL != host_mac)
+    clib_memcpy (&mp->host_mac[0], host_mac, 6);
 
   mp->_vl_msg_id = ntohs (VL_API_DHCP_COMPL_EVENT);