From 6f4aee61a2e741b8ba6f91b5922ddafafda5b587 Mon Sep 17 00:00:00 2001
From: Santosh P K <sapk@vmware.com>
Date: Thu, 20 Feb 2020 10:50:14 -0800
Subject: [PATCH] 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>
---
 zebra/zapi_msg.c |  5 +++--
 zebra/zebra_gr.c | 49 +++++++++++++++++++++++++++---------------------
 zebra/zserv.c    |  4 ++--
 zebra/zserv.h    |  4 ++++
 4 files changed, 37 insertions(+), 25 deletions(-)

diff --git a/zebra/zapi_msg.c b/zebra/zapi_msg.c
index 6012962b1c..9d9d5ea8f7 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 e8c7304f44..6d3829110e 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 2a5352a1da..299c079df1 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 77ea19202f..6a075cc9a7 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.
  *
-- 
2.39.5