Zebra: Zebra gr dynamic client handling.

When a client connects to zebra with GR capabilities and
then restarts, it might disconnect again even before hello is
sent leading zebra cores.

GR should be supported only for dynamic neighbor who are capable
of restarting.

Signed-off-by: Santosh P K <sapk@vmware.com>

4 files changed, 37 insertions, 25 deletions

diff --git a/zebra/zapi_msg.c b/zebra/zapi_msg.c
index 6012962b1..9d9d5ea8f 100644
--- a/zebra/zapi_msg.c
+++ b/zebra/zapi_msg.c
@@ -1773,10 +1773,11 @@ static void zread_hello(ZAPI_HANDLER_ARGS)
 
 		client->proto = proto;
 		client->instance = instance;
+
+		/* Graceful restart processing for client connect */
+		zebra_gr_client_reconnect(client);
 	}
 
-	/* Graceful restart processing for client connect */
-	zebra_gr_client_reconnect(client);
 	zsend_capabilities(client, zvrf);
 	zebra_vrf_update_all(client);
 stream_failure:
diff --git a/zebra/zebra_gr.c b/zebra/zebra_gr.c
index e8c7304f4..6d3829110 100644
--- a/zebra/zebra_gr.c
+++ b/zebra/zebra_gr.c
@@ -265,30 +265,31 @@ void zebra_gr_client_reconnect(struct zserv *client)
 	}
 
 	/* Copy the timers */
-	if (old_client) {
-		client->gr_instance_count = old_client->gr_instance_count;
-		client->restart_time = old_client->restart_time;
-
-		LOG_GR("%s : old client %s, gr_instance_count %d", __func__,
-		       zebra_route_string(old_client->proto),
-		       old_client->gr_instance_count);
-
-		if (TAILQ_FIRST(&old_client->gr_info_queue)) {
-			TAILQ_CONCAT(&client->gr_info_queue,
-				     &old_client->gr_info_queue, gr_info);
-			TAILQ_INIT(&old_client->gr_info_queue);
-		}
+	if (!old_client)
+		return;
 
-		TAILQ_FOREACH (info, &client->gr_info_queue, gr_info) {
-			info->stale_client_ptr = client;
-			info->stale_client = false;
-		}
+	client->gr_instance_count = old_client->gr_instance_count;
+	client->restart_time = old_client->restart_time;
+
+	LOG_GR("%s : old client %s, gr_instance_count %d", __func__,
+	       zebra_route_string(old_client->proto),
+	       old_client->gr_instance_count);
+
+	if (TAILQ_FIRST(&old_client->gr_info_queue)) {
+		TAILQ_CONCAT(&client->gr_info_queue, &old_client->gr_info_queue,
+			     gr_info);
+		TAILQ_INIT(&old_client->gr_info_queue);
+	}
 
-		/* Delete the stale client */
-		listnode_delete(zrouter.stale_client_list, old_client);
-		/* Delete old client */
-		XFREE(MTYPE_TMP, old_client);
+	TAILQ_FOREACH (info, &client->gr_info_queue, gr_info) {
+		info->stale_client_ptr = client;
+		info->stale_client = false;
 	}
+
+	/* Delete the stale client */
+	listnode_delete(zrouter.stale_client_list, old_client);
+	/* Delete old client */
+	XFREE(MTYPE_TMP, old_client);
 }
 
 /*
@@ -425,6 +426,12 @@ void zread_client_capabilities(ZAPI_HANDLER_ARGS)
 		return;
 	}
 
+	/* GR only for dynamic clients */
+	if (client->proto <= ZEBRA_ROUTE_CONNECT) {
+		LOG_GR("%s: GR capabilities for client %s not supported",
+		       __func__, zebra_route_string(client->proto));
+		return;
+	}
 	/* Call the capabilities handler */
 	zebra_client_capabilities_handler(client, &api);
 }
diff --git a/zebra/zserv.c b/zebra/zserv.c
index 2a5352a1d..299c079df 100644
--- a/zebra/zserv.c
+++ b/zebra/zserv.c
@@ -568,7 +568,7 @@ static void zserv_client_free(struct zserv *client)
 
 		close(client->sock);
 
-		if (!client->gr_instance_count) {
+		if (DYNAMIC_CLIENT_GR_DISABLED(client)) {
 			nroutes = rib_score_proto(client->proto,
 						  client->instance);
 			zlog_notice(
@@ -610,7 +610,7 @@ static void zserv_client_free(struct zserv *client)
 	 * If any instance are graceful restart enabled,
 	 * client is not deleted
 	 */
-	if (!client->gr_instance_count) {
+	if (DYNAMIC_CLIENT_GR_DISABLED(client)) {
 		if (IS_ZEBRA_DEBUG_EVENT)
 			zlog_debug("%s: Deleting client %s", __func__,
 				   zebra_route_string(client->proto));
diff --git a/zebra/zserv.h b/zebra/zserv.h
index 77ea19202..6a075cc9a 100644
--- a/zebra/zserv.h
+++ b/zebra/zserv.h
@@ -229,6 +229,10 @@ struct zserv {
 DECLARE_HOOK(zserv_client_connect, (struct zserv *client), (client));
 DECLARE_KOOH(zserv_client_close, (struct zserv *client), (client));
 
+#define DYNAMIC_CLIENT_GR_DISABLED(_client)                                    \
+	((_client->proto <= ZEBRA_ROUTE_CONNECT)                               \
+	 || !(_client->gr_instance_count))
+
 /*
  * Initialize Zebra API server.
  *