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, 24 insertions, 5 deletions

diff --git a/vnet/vnet/fib/fib_test.c b/vnet/vnet/fib/fib_test.c
index 7729209d6ab..1e459cf1a6c 100644
--- a/vnet/vnet/fib/fib_test.c
+++ b/vnet/vnet/fib/fib_test.c
@@ -222,6 +222,19 @@ fib_test_urpf_is_equal (fib_node_index_t fei,
     return (1);
 }
 
+static u8*
+fib_test_build_rewrite (u8 *eth_addr)
+{
+    u8* rewrite = NULL;
+
+    vec_validate(rewrite, 13);
+
+    memcpy(rewrite, eth_addr, 6);
+    memcpy(rewrite+6, eth_addr, 6);
+
+    return (rewrite);
+}
+
 static void
 fib_test_v4 (void)
 {
@@ -523,6 +536,7 @@ fib_test_v4 (void)
     u8 eth_addr[] = {
 	0xde, 0xde, 0xde, 0xba, 0xba, 0xba,
     };
+
     ip46_address_t nh_12_12_12_12 = {
 	.ip4.as_u32 = clib_host_to_net_u32(0x0c0c0c0c),
     };
@@ -561,7 +575,8 @@ fib_test_v4 (void)
 				    &adj->sub_type.nbr.next_hop)),
 	      "adj nbr next-hop ok");
 
-    adj_nbr_update_rewrite(ai_01, eth_addr);
+    adj_nbr_update_rewrite(ai_01, ADJ_NBR_REWRITE_FLAG_COMPLETE,
+			   fib_test_build_rewrite(eth_addr));
     FIB_TEST((IP_LOOKUP_NEXT_REWRITE == adj->lookup_next_index),
 	     "adj is complete");
     FIB_TEST((0 == ip46_address_cmp(&pfx_10_10_10_1_s_32.fp_addr,
@@ -589,7 +604,8 @@ fib_test_v4 (void)
     FIB_TEST((0 == ip46_address_cmp(&nh_12_12_12_12,
 				    &adj->sub_type.nbr.next_hop)),
 	      "adj nbr next-hop ok");
-    adj_nbr_update_rewrite(ai_12_12_12_12, eth_addr);
+    adj_nbr_update_rewrite(ai_12_12_12_12, ADJ_NBR_REWRITE_FLAG_COMPLETE,
+			   fib_test_build_rewrite(eth_addr));
     FIB_TEST((IP_LOOKUP_NEXT_REWRITE == adj->lookup_next_index),
 	     "adj is complete");
 
@@ -636,7 +652,8 @@ fib_test_v4 (void)
 				    &adj->sub_type.nbr.next_hop)),
 	      "adj nbr next-hop ok");
 
-    adj_nbr_update_rewrite(ai_02, eth_addr);
+    adj_nbr_update_rewrite(ai_02, ADJ_NBR_REWRITE_FLAG_COMPLETE,
+			   fib_test_build_rewrite(eth_addr));
     FIB_TEST((IP_LOOKUP_NEXT_REWRITE == adj->lookup_next_index),
 	     "adj is complete");
     FIB_TEST((0 == ip46_address_cmp(&pfx_10_10_10_2_s_32.fp_addr,
@@ -3113,7 +3130,8 @@ fib_test_v6 (void)
 				    &adj->sub_type.nbr.next_hop)),
 	      "adj nbr next-hop ok");
 
-    adj_nbr_update_rewrite(ai_01, eth_addr);
+    adj_nbr_update_rewrite(ai_01, ADJ_NBR_REWRITE_FLAG_COMPLETE,
+			   fib_test_build_rewrite(eth_addr));
     FIB_TEST((IP_LOOKUP_NEXT_REWRITE == adj->lookup_next_index),
 	     "adj is complete");
     FIB_TEST((0 == ip46_address_cmp(&pfx_2001_1_2_s_128.fp_addr,
@@ -3150,7 +3168,8 @@ fib_test_v6 (void)
 				    &adj->sub_type.nbr.next_hop)),
 	      "adj nbr next-hop ok");
 
-    adj_nbr_update_rewrite(ai_02, eth_addr);
+    adj_nbr_update_rewrite(ai_02, ADJ_NBR_REWRITE_FLAG_COMPLETE,
+			   fib_test_build_rewrite(eth_addr));
     FIB_TEST((IP_LOOKUP_NEXT_REWRITE == adj->lookup_next_index),
 	     "adj is complete");
     FIB_TEST((0 == ip46_address_cmp(&pfx_2001_1_3_s_128.fp_addr,