bgpd: Update source address for BFD session

If BFD is down, we should try to detect the source automatically from the given
interface.

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

diff --git a/bgpd/bgp_bfd.c b/bgpd/bgp_bfd.c
index 82dd0b593eaeb9182cc3ab93776f4eaeabab9e9c..3f4ef7d5b2fa37637deaed2084c60902290278af 100644 (file)
--- a/bgpd/bgp_bfd.c
+++ b/bgpd/bgp_bfd.c
@@ -26,6 +26,7 @@
 #include "bgpd/bgp_debug.h"
 #include "bgpd/bgp_vty.h"
 #include "bgpd/bgp_packet.h"
+#include "bgpd/bgp_network.h"
 
 DEFINE_MTYPE_STATIC(BGPD, BFD_CONFIG, "BFD configuration data");
 
@@ -153,6 +154,8 @@ void bgp_peer_bfd_update_source(struct peer *p)
                struct in_addr v4;
                struct in6_addr v6;
        } src, dst;
+       struct interface *ifp;
+       union sockunion addr;
 
        if (!p->bfd_config)
                return;
@@ -163,10 +166,25 @@ void bgp_peer_bfd_update_source(struct peer *p)
                return;
 
        /* Figure out the correct source to use. */
-       if (CHECK_FLAG(p->flags, PEER_FLAG_UPDATE_SOURCE) && p->update_source)
-               source = p->update_source;
-       else
+       if (CHECK_FLAG(p->flags, PEER_FLAG_UPDATE_SOURCE)) {
+               if (p->update_source) {
+                       source = p->update_source;
+               } else if (p->update_if) {
+                       ifp = if_lookup_by_name(p->update_if, p->bgp->vrf_id);
+                       if (ifp) {
+                               sockunion_init(&addr);
+                               if (bgp_update_address(ifp, &p->connection->su, &addr)) {
+                                       if (BGP_DEBUG(bfd, BFD_LIB))
+                                               zlog_debug("%s: can't find the source address for interface %s",
+                                                          __func__, p->update_if);
+                               }
+
+                               source = &addr;
+                       }
+               }
+       } else {
                source = p->su_local;
+       }
 
        /* Update peer's source/destination addresses. */
        bfd_sess_addresses(session, &family, &src.v6, &dst.v6);