ospf: BFD down not tearing down OSPF adjacency for point-to-point network

Root Cause:
Lookup for the point-to-point neighbor was failing because the neighbor
lookup was based on neighbor interface IP address. But, for point-to-point
neighbor the key is router-id for lookup. Lookup failure was causing the
BFD updates from PTM to get dropped.

Fix:
Added walk of the neighbor list if the network type is point-to-point to
find the appropriate neighbor. The match is based on source IP address of
the neighbor since that’s the address registered with BFD for monitoring.

Ticket: CM-20411
Signed-off-by: Radhika Mahankali <radhika@cumulusnetworks.com>

diff --git a/ospfd/ospf_bfd.c b/ospfd/ospf_bfd.c
index 73802ce13e83aaff8f97f9e299a449715b99da36..b9e78f4cd35df77753c6310299e5fde75a057fba 100644 (file)
--- a/ospfd/ospf_bfd.c
+++ b/ospfd/ospf_bfd.c
@@ -202,8 +202,9 @@ static int ospf_bfd_interface_dest_update(ZAPI_CALLBACK_ARGS)
        struct interface *ifp;
        struct ospf_interface *oi;
        struct ospf_if_params *params;
-       struct ospf_neighbor *nbr;
+       struct ospf_neighbor *nbr = NULL;
        struct route_node *node;
+       struct route_node *n_node;
        struct prefix p;
        int status;
        int old_status;
@@ -231,7 +232,28 @@ static int ospf_bfd_interface_dest_update(ZAPI_CALLBACK_ARGS)
                if ((oi = node->info) == NULL)
                        continue;
 
-               nbr = ospf_nbr_lookup_by_addr(oi->nbrs, &p.u.prefix4);
+               /* walk the neighbor list for point-to-point network */
+               if (oi->type == OSPF_IFTYPE_POINTOPOINT) {
+                       for (n_node = route_top(oi->nbrs); n_node;
+                               n_node = route_next(n_node)) {
+                               nbr = n_node->info;
+                               if (nbr) {
+                                       /* skip myself */
+                                       if (nbr == oi->nbr_self) {
+                                               nbr = NULL;
+                                               continue;
+                                       }
+
+                                       /* Found the matching neighbor */
+                                       if (nbr->src.s_addr ==
+                                               p.u.prefix4.s_addr)
+                                               break;
+                               }
+                       }
+               } else {
+                       nbr = ospf_nbr_lookup_by_addr(oi->nbrs, &p.u.prefix4);
+               }
+
                if (!nbr || !nbr->bfd_info)
                        continue;