bgpd: update BFD config on update-source change

Update BFD sessions when the update-source configuration is set so the
session follows the new configured source address.

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>
(cherry picked from commit 7196f56)

Author: rzalamena

bgpd/bgp_bfd.c

@@ -150,6 +150,7 @@ void bgp_peer_config_apply(struct peer *p, struct peer_group *pg)
 void bgp_peer_bfd_update_source(struct peer *p)
 {
 	struct bfd_session_params *session = p->bfd_config->session;
+	const union sockunion *source;
 	bool changed = false;
 	int family;
 	union {
@@ -161,44 +162,45 @@ void bgp_peer_bfd_update_source(struct peer *p)
 	if (CHECK_FLAG(p->sflags, PEER_STATUS_GROUP))
 		return;
 
+	/* Figure out the correct source to use. */
+	if (CHECK_FLAG(p->flags, PEER_FLAG_UPDATE_SOURCE))
+		source = p->update_source;
+	else
+		source = p->su_local;
+
 	/* Update peer's source/destination addresses. */
 	bfd_sess_addresses(session, &family, &src.v6, &dst.v6);
 	if (family == AF_INET) {
-		if ((p->su_local
-		     && p->su_local->sin.sin_addr.s_addr != src.v4.s_addr)
+		if ((source && source->sin.sin_addr.s_addr != src.v4.s_addr)
 		    || p->su.sin.sin_addr.s_addr != dst.v4.s_addr) {
 			if (BGP_DEBUG(bfd, BFD_LIB))
 				zlog_debug(
 					"%s: address [%pI4->%pI4] to [%pI4->%pI4]",
 					__func__, &src.v4, &dst.v4,
-					p->su_local ? &p->su_local->sin.sin_addr
-						    : &src.v4,
+					source ? &source->sin.sin_addr
+					       : &src.v4,
 					&p->su.sin.sin_addr);
 
 			bfd_sess_set_ipv4_addrs(
-				session,
-				p->su_local ? &p->su_local->sin.sin_addr : NULL,
+				session, source ? &source->sin.sin_addr : NULL,
 				&p->su.sin.sin_addr);
 			changed = true;
 		}
 	} else {
-		if ((p->su_local
-		     && memcmp(&p->su_local->sin6, &src.v6, sizeof(src.v6)))
+		if ((source && memcmp(&source->sin6, &src.v6, sizeof(src.v6)))
 		    || memcmp(&p->su.sin6, &dst.v6, sizeof(dst.v6))) {
 			if (BGP_DEBUG(bfd, BFD_LIB))
 				zlog_debug(
 					"%s: address [%pI6->%pI6] to [%pI6->%pI6]",
 					__func__, &src.v6, &dst.v6,
-					p->su_local
-						? &p->su_local->sin6.sin6_addr
-						: &src.v6,
+					source ? &source->sin6.sin6_addr
+					       : &src.v6,
 					&p->su.sin6.sin6_addr);
 
-			bfd_sess_set_ipv6_addrs(
-				session,
-				p->su_local ? &p->su_local->sin6.sin6_addr
-					    : NULL,
-				&p->su.sin6.sin6_addr);
+			bfd_sess_set_ipv6_addrs(session,
+						source ? &source->sin6.sin6_addr
+						       : NULL,
+						&p->su.sin6.sin6_addr);
 			changed = true;
 		}
 	}

bgpd/bgpd.c

@@ -4875,6 +4875,10 @@ int peer_update_source_if_set(struct peer *peer, const char *ifname)
 		} else
 			bgp_session_reset(peer);
 
+		/* Apply new source configuration to BFD session. */
+		if (peer->bfd_config)
+			bgp_peer_bfd_update_source(peer);
+
 		/* Skip peer-group mechanics for regular peers. */
 		return 0;
 	}
@@ -4908,6 +4912,10 @@ int peer_update_source_if_set(struct peer *peer, const char *ifname)
 					BGP_NOTIFY_CEASE_CONFIG_CHANGE);
 		} else
 			bgp_session_reset(member);
+
+		/* Apply new source configuration to BFD session. */
+		if (member->bfd_config)
+			bgp_peer_bfd_update_source(member);
 	}
 
 	return 0;
@@ -4938,6 +4946,10 @@ int peer_update_source_addr_set(struct peer *peer, const union sockunion *su)
 		} else
 			bgp_session_reset(peer);
 
+		/* Apply new source configuration to BFD session. */
+		if (peer->bfd_config)
+			bgp_peer_bfd_update_source(peer);
+
 		/* Skip peer-group mechanics for regular peers. */
 		return 0;
 	}
@@ -4970,6 +4982,10 @@ int peer_update_source_addr_set(struct peer *peer, const union sockunion *su)
 					BGP_NOTIFY_CEASE_CONFIG_CHANGE);
 		} else
 			bgp_session_reset(member);
+
+		/* Apply new source configuration to BFD session. */
+		if (member->bfd_config)
+			bgp_peer_bfd_update_source(member);
 	}
 
 	return 0;
@@ -5007,6 +5023,10 @@ int peer_update_source_unset(struct peer *peer)
 		} else
 			bgp_session_reset(peer);
 
+		/* Apply new source configuration to BFD session. */
+		if (peer->bfd_config)
+			bgp_peer_bfd_update_source(peer);
+
 		/* Skip peer-group mechanics for regular peers. */
 		return 0;
 	}
@@ -5038,6 +5058,10 @@ int peer_update_source_unset(struct peer *peer)
 					BGP_NOTIFY_CEASE_CONFIG_CHANGE);
 		} else
 			bgp_session_reset(member);
+
+		/* Apply new source configuration to BFD session. */
+		if (member->bfd_config)
+			bgp_peer_bfd_update_source(member);
 	}
 
 	return 0;