ldpd: use a timer instead of sleeping in LM init

Stop sleeping if synchronous label-manager zapi session
has trouble during init: retry using a timer instead. Move
initial label-block request to a point where the LM zapi
session is known to be running.

Signed-off-by: Mark Stapp <mjs@voltanet.io>

ldpd/lde.c

@@ -174,7 +174,6 @@ lde_init(struct ldpd_init *init)
 	frr_zclient_addr(&zclient_addr, &zclient_addr_len,
 			 init->zclient_serv_path);
 	zclient_sync_init(init->instance);
-	lde_label_list_init();
 }
 
 static void
@@ -1746,9 +1745,19 @@ lde_address_list_free(struct lde_nbr *ln)
 		free(lde_addr);
 }
 
+static int zclient_sync_retry(struct thread *thread)
+{
+	unsigned short instance = (intptr_t)THREAD_ARG(thread);
+
+	zclient_sync_init(instance);
+
+	return 0;
+}
+
 static void zclient_sync_init(unsigned short instance)
 {
 	struct zclient_options options = zclient_options_default;
+
 	options.synchronous = true;
 
 	/* Initialize special zclient for synchronous message exchanges. */
@@ -1759,24 +1768,40 @@ static void zclient_sync_init(unsigned short instance)
 	zclient_sync->session_id = 1; /* Distinguish from main session */
 	zclient_sync->privs = &lde_privs;
 
-	while (zclient_socket_connect(zclient_sync) < 0) {
+	if (zclient_socket_connect(zclient_sync) < 0) {
 		log_warnx("Error connecting synchronous zclient!");
-		sleep(1);
+		goto retry;
 	}
 	/* make socket non-blocking */
 	sock_set_nonblock(zclient_sync->sock);
 
 	/* Send hello to notify zebra this is a synchronous client */
-	while (zclient_send_hello(zclient_sync) < 0) {
+	if (zclient_send_hello(zclient_sync) < 0) {
 		log_warnx("Error sending hello for synchronous zclient!");
-		sleep(1);
+		goto retry;
 	}
 
 	/* Connect to label manager */
-	while (lm_label_manager_connect(zclient_sync, 0) != 0) {
+	if (lm_label_manager_connect(zclient_sync, 0) != 0) {
 		log_warnx("Error connecting to label manager!");
-		sleep(1);
+		goto retry;
 	}
+
+	/* Finish init once the LM session is running */
+	lde_label_list_init();
+
+	return;
+
+retry:
+
+	/* Discard failed zclient object */
+	zclient_stop(zclient_sync);
+	zclient_free(zclient_sync);
+	zclient_sync = NULL;
+
+	/* Retry using a timer */
+	thread_add_timer(master, zclient_sync_retry,
+			 (void *)(intptr_t)instance, 1, NULL);
 }
 
 static void