ldpd: Option for disabled LDP hello message during TCP

Added option "disable-establish-hello" that disableds
sending additional LDP hello multicast messages during
TCP session establishment.
This option enables per interface: "(config-ldp-af-if)".

Signed-off-by: Andrii Melnychenko <a.melnychenko@vyos.io>

ldpd/interface.c

@@ -63,11 +63,13 @@ if_new(const char *name)
 	iface->ipv4.af = AF_INET;
 	iface->ipv4.iface = iface;
 	iface->ipv4.enabled = 0;
+	iface->ipv4.disable_establish_hello = 0;
 
 	/* ipv6 */
 	iface->ipv6.af = AF_INET6;
 	iface->ipv6.iface = iface;
 	iface->ipv6.enabled = 0;
+	iface->ipv6.disable_establish_hello = 0;
 
 	return (iface);
 }

ldpd/ldp_vty.h

@@ -24,6 +24,7 @@ int	 ldp_vty_allow_broken_lsp(struct vty *, const char *);
 int	 ldp_vty_address_family (struct vty *, const char *, const char *);
 int	 ldp_vty_disc_holdtime(struct vty *, const char *, enum hello_type, long);
 int	 ldp_vty_disc_interval(struct vty *, const char *, enum hello_type, long);
+int	 ldp_vty_disable_establish_hello(struct vty *, const char *);
 int	 ldp_vty_targeted_hello_accept(struct vty *, const char *, const char *);
 int	 ldp_vty_nbr_session_holdtime(struct vty *, const char *, struct in_addr, long);
 int	 ldp_vty_af_session_holdtime(struct vty *, const char *, long);

ldpd/ldp_vty_cmds.c

@@ -122,6 +122,15 @@ DEFPY  (ldp_discovery_link_interval,
 	return (ldp_vty_disc_interval(vty, no, HELLO_LINK, interval));
 }
 
+DEFPY  (ldp_disable_establish_hello,
+	ldp_disable_establish_hello_cmd,
+	"[no] disable-establish-hello",
+	NO_STR
+	"Disable sending additional LDP hello message on establishing LDP tcp connection\n")
+{
+	return ldp_vty_disable_establish_hello(vty, no);
+}
+
 DEFPY  (ldp_discovery_targeted_interval,
 	ldp_discovery_targeted_interval_cmd,
 	"[no] discovery targeted-hello interval (1-65535)$interval",
@@ -866,9 +875,11 @@ ldp_vty_init (void)
 
 	install_element(LDP_IPV4_IFACE_NODE, &ldp_discovery_link_holdtime_cmd);
 	install_element(LDP_IPV4_IFACE_NODE, &ldp_discovery_link_interval_cmd);
+	install_element(LDP_IPV4_IFACE_NODE, &ldp_disable_establish_hello_cmd);
 
 	install_element(LDP_IPV6_IFACE_NODE, &ldp_discovery_link_holdtime_cmd);
 	install_element(LDP_IPV6_IFACE_NODE, &ldp_discovery_link_interval_cmd);
+	install_element(LDP_IPV6_IFACE_NODE, &ldp_disable_establish_hello_cmd);
 
 	install_element(LDP_L2VPN_NODE, &ldp_bridge_cmd);
 	install_element(LDP_L2VPN_NODE, &ldp_mtu_cmd);

ldpd/ldp_vty_conf.c

@@ -119,6 +119,8 @@ ldp_af_iface_config_write(struct vty *vty, int af)
 		    ia->hello_interval != 0)
 			vty_out (vty, "   discovery hello interval %u\n",
 			    ia->hello_interval);
+		if (ia->disable_establish_hello)
+			vty_out (vty, "   disable-establish-hello\n");
 
 		vty_out (vty, "  exit\n");
 	}
@@ -632,6 +634,36 @@ ldp_vty_disc_interval(struct vty *vty, const char *negate,
 	return (CMD_SUCCESS);
 }
 
+int
+ldp_vty_disable_establish_hello(struct vty *vty,
+	const char *negate)
+{
+	struct iface		*iface;
+	struct iface_af		*ia;
+	int			 af;
+
+	switch (vty->node) {
+	case LDP_IPV4_IFACE_NODE:
+	case LDP_IPV6_IFACE_NODE:
+		af = ldp_vty_get_af(vty);
+		iface = VTY_GET_CONTEXT(iface);
+		VTY_CHECK_CONTEXT(iface);
+
+		ia = iface_af_get(iface, af);
+		if (negate)
+			ia->disable_establish_hello = 0;
+		else
+			ia->disable_establish_hello = 1;
+
+		ldp_config_apply(vty, vty_conf);
+		break;
+	default:
+		fatalx("ldp_vty_disable_establish_hello: unexpected node");
+	}
+
+	return (CMD_SUCCESS);
+}
+
 int
 ldp_vty_targeted_hello_accept(struct vty *vty, const char *negate,
     const char *acl_from_str)

ldpd/ldpd.c

@@ -1604,6 +1604,7 @@ merge_iface_af(struct iface_af *ia, struct iface_af *xi)
 	}
 	ia->hello_holdtime = xi->hello_holdtime;
 	ia->hello_interval = xi->hello_interval;
+	ia->disable_establish_hello = xi->disable_establish_hello;
 }
 
 static void

ldpd/ldpd.h

@@ -332,6 +332,7 @@ struct iface_af {
 	struct event *hello_timer;
 	uint16_t		 hello_holdtime;
 	uint16_t		 hello_interval;
+	int disable_establish_hello;
 };
 
 struct iface_ldp_sync {

ldpd/neighbor.c

@@ -630,8 +630,9 @@ nbr_establish_connection(struct nbr *nbr)
 	 * an adjacency as well.
 	 */
 	RB_FOREACH(adj, nbr_adj_head, &nbr->adj_tree)
-		send_hello(adj->source.type, adj->source.link.ia,
+		if (!(adj->source.type == HELLO_LINK && adj->source.link.ia->disable_establish_hello))
-		    adj->source.target);
+			send_hello(adj->source.type, adj->source.link.ia,
+				adj->source.target);
 
 	if (connect(nbr->fd, &remote_su.sa, sockaddr_len(&remote_su.sa)) == -1) {
 		if (errno == EINPROGRESS) {