bgpd: Fix some bugs of set tcp-mss on listen socket.

    1.Tcp-mss not just for bgp neighbor, but also for bgp neighbor group.
    2.Set tcp-mss for listhen socket even no neighbor config passive mode.
    3.Config tcp-mss on neighbor group sync to all the neighbor in that group.

.gitignore

@@ -117,3 +117,5 @@ refix
 /test-suite.log
 pceplib/test/*.log
 pceplib/test/*.trs
+*.si4project*
+*gitignore*

bgpd/bgp_network.c

@@ -341,6 +341,7 @@ int bgp_tcp_mss_set(struct peer *peer)
 	struct bgp_listener *listener;
 	uint32_t min_mss = 0;
 	struct peer *p;
+	struct peer_group *group;
 
 	for (ALL_LIST_ELEMENTS_RO(peer->bgp->peer, node, p)) {
 		if (!CHECK_FLAG(p->flags, PEER_FLAG_TCP_MSS))
@@ -355,6 +356,21 @@ int bgp_tcp_mss_set(struct peer *peer)
 		min_mss = MIN(min_mss, p->tcp_mss);
 	}
 
+	for (ALL_LIST_ELEMENTS_RO(peer->bgp->group, node, group)) {
+		p = group->conf;
+		if (!CHECK_FLAG(p->flags, PEER_FLAG_TCP_MSS))
+			continue;
+
+		if (!p->tcp_mss)
+			continue;
+
+		if (!min_mss)
+			min_mss = p->tcp_mss;
+
+		min_mss = MIN(min_mss, p->tcp_mss);
+	}
+
+
 	frr_with_privs(&bgpd_privs) {
 		for (ALL_LIST_ELEMENTS_RO(bm->listen_sockets, node, listener)) {
 			if (listener->su.sa.sa_family !=
@@ -371,7 +387,7 @@ int bgp_tcp_mss_set(struct peer *peer)
 			 * one peer that is in passive mode. Otherwise, TCP MSS
 			 * is set per socket via bgp_connect().
 			 */
-			if (CHECK_FLAG(peer->flags, PEER_FLAG_PASSIVE))
+			if (min_mss != 0)
 				sockopt_tcp_mss_set(listener->fd, min_mss);
 
 			break;

bgpd/bgpd.c

@@ -5777,8 +5777,19 @@ void peer_port_unset(struct peer *peer)
  */
 void peer_tcp_mss_set(struct peer *peer, uint32_t tcp_mss)
 {
+	struct listnode *node;
+	struct peer *p;
+
 	peer->tcp_mss = tcp_mss;
 	SET_FLAG(peer->flags, PEER_FLAG_TCP_MSS);
+
+	if (CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP)) {
+		for (ALL_LIST_ELEMENTS_RO(peer->group->peer, node, p)) {
+			p->tcp_mss = tcp_mss;
+			SET_FLAG(p->flags, PEER_FLAG_TCP_MSS);
+		}
+	}
+
 	bgp_tcp_mss_set(peer);
 }
 
@@ -5788,8 +5799,19 @@ void peer_tcp_mss_set(struct peer *peer, uint32_t tcp_mss)
  */
 void peer_tcp_mss_unset(struct peer *peer)
 {
+	struct listnode *node;
+	struct peer *p;
+
 	UNSET_FLAG(peer->flags, PEER_FLAG_TCP_MSS);
 	peer->tcp_mss = 0;
+
+	if (CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP)) {
+		for (ALL_LIST_ELEMENTS_RO(peer->group->peer, node, p)) {
+			UNSET_FLAG(p->flags, PEER_FLAG_TCP_MSS);
+			p->tcp_mss = 0;
+		}
+	}
+
 	bgp_tcp_mss_set(peer);
 }