BGP: Do not get out of bgp_start() if peer's IP address isn't known

Ticket: CM-7140
Reviewed By: CCR-3412
Testing Done: bgpsmoke, Atul verified fix

BGP Unnumbered and Interface based peering can interact in some strange
ways. One of them is when there's an IPv4 address on a link on which
BGP Unnumbered session is beng attempted, but the IPv4 address is not
a /30 or /31. As per the bug report, we end up attempting to start the
BGP FSM on receiving a notification that an IPv4 address is present on
an interface. To avoid attempting to go past BGP's start state in the
absence of a valid peer address is the right thing to do. And this
simple patch does just that.

Signed-off-by: Dinesh G Dutt <ddutt@cumulusnetworks.com>
Reviewed-by: Donald Sharp <sharpd@cumulusnetworks.com>
Reviewed-by:   Vipin Kumar <vipin@cumulusnetworks.com>

diff --git a/bgpd/bgp_fsm.c b/bgpd/bgp_fsm.c
index c8605da956c4513b06070fc245ba090b27e5904c..9bfb7304693e41953bc74cf7439e74f4f1338068 100644 (file)
--- a/bgpd/bgp_fsm.c
+++ b/bgpd/bgp_fsm.c
@@ -1256,6 +1256,14 @@ bgp_start (struct peer *peer)
 
   bgp_peer_conf_if_to_su_update(peer);
 
+  if (peer->su.sa.sa_family == AF_UNSPEC)
+    {
+      if (bgp_debug_neighbor_events(peer))
+        zlog_debug ("%s [FSM] Unable to get neighbor's IP address, waiting...",
+                   peer->host);
+      return -1;
+    }
+
   if (BGP_PEER_START_SUPPRESSED (peer))
     {
       if (bgp_debug_neighbor_events(peer))