zebra: Synchronous client queues accumulate messages from zebra.

Zebra is currently sending messages on interface add/delete/update,
VRF add/delete, and interface address change - regardless of whether
its clients had requested them.  This is problematic for lde and isis,
which only listens to label chunk messages, and only when it is
waiting for one (synchronous client). The effect is the that messages
accumulate on the lde synchronous message queue.

With this change:
  - Zebra does not send unsolicited messages to synchronous clients.
  - Synchronous clients send a ZEBRA_HELLO to zebra.
    The ZEBRA_HELLO contains a new boolean field: sychronous.
  - LDP and PIM have been updated to send a ZEBRA_HELLO for their
    synchronous clients.

Signed-off-by: Karen Schoener <karen@voltanet.io>

1 files changed, 48 insertions, 3 deletions

diff --git a/zebra/redistribute.c b/zebra/redistribute.c
index 32051a62b7..08716ec388 100644
--- a/zebra/redistribute.c
+++ b/zebra/redistribute.c
@@ -288,6 +288,10 @@ void redistribute_delete(const struct prefix *p, const struct prefix *src_p,
 	}
 
 	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		if (new_re) {
 			/* Skip this client if it will receive an update for the
 			 * 'new' re
@@ -469,6 +473,12 @@ void zebra_interface_up_update(struct interface *ifp)
 	if (ifp->ptm_status || !ifp->ptm_enable) {
 		for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode,
 				       client)) {
+			/* Do not send unsolicited messages to synchronous
+			 * clients.
+			 */
+			if (client->synchronous)
+				continue;
+
 			zsend_interface_update(ZEBRA_INTERFACE_UP,
 					       client, ifp);
 			zsend_interface_link_params(client, ifp);
@@ -487,6 +497,10 @@ void zebra_interface_down_update(struct interface *ifp)
 			   ifp->name, ifp->vrf_id);
 
 	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		zsend_interface_update(ZEBRA_INTERFACE_DOWN, client, ifp);
 	}
 }
@@ -502,6 +516,10 @@ void zebra_interface_add_update(struct interface *ifp)
 			   ifp->vrf_id);
 
 	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		client->ifadd_cnt++;
 		zsend_interface_add(client, ifp);
 		zsend_interface_link_params(client, ifp);
@@ -518,6 +536,10 @@ void zebra_interface_delete_update(struct interface *ifp)
 			   ifp->name, ifp->vrf_id);
 
 	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		client->ifdel_cnt++;
 		zsend_interface_delete(client, ifp);
 	}
@@ -549,12 +571,17 @@ void zebra_interface_address_add_update(struct interface *ifp,
 
 	router_id_add_address(ifc);
 
-	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client))
+	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		if (CHECK_FLAG(ifc->conf, ZEBRA_IFC_REAL)) {
 			client->connected_rt_add_cnt++;
 			zsend_interface_address(ZEBRA_INTERFACE_ADDRESS_ADD,
 						client, ifp, ifc);
 		}
+	}
 }
 
 /* Interface address deletion. */
@@ -578,12 +605,17 @@ void zebra_interface_address_delete_update(struct interface *ifp,
 
 	router_id_del_address(ifc);
 
-	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client))
+	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		if (CHECK_FLAG(ifc->conf, ZEBRA_IFC_REAL)) {
 			client->connected_rt_del_cnt++;
 			zsend_interface_address(ZEBRA_INTERFACE_ADDRESS_DELETE,
 						client, ifp, ifc);
 		}
+	}
 }
 
 /* Interface VRF change. May need to delete from clients not interested in
@@ -600,6 +632,10 @@ void zebra_interface_vrf_update_del(struct interface *ifp, vrf_id_t new_vrf_id)
 			ifp->name, ifp->vrf_id, new_vrf_id);
 
 	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		/* Need to delete if the client is not interested in the new
 		 * VRF. */
 		zsend_interface_update(ZEBRA_INTERFACE_DOWN, client, ifp);
@@ -623,6 +659,10 @@ void zebra_interface_vrf_update_add(struct interface *ifp, vrf_id_t old_vrf_id)
 			ifp->name, old_vrf_id, ifp->vrf_id);
 
 	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		/* Need to add if the client is interested in the new VRF. */
 		client->ifadd_cnt++;
 		zsend_interface_add(client, ifp);
@@ -910,6 +950,11 @@ void zebra_interface_parameters_update(struct interface *ifp)
 		zlog_debug("MESSAGE: ZEBRA_INTERFACE_LINK_PARAMS %s(%u)",
 			   ifp->name, ifp->vrf_id);
 
-	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client))
+	for (ALL_LIST_ELEMENTS(zrouter.client_list, node, nnode, client)) {
+		/* Do not send unsolicited messages to synchronous clients. */
+		if (client->synchronous)
+			continue;
+
 		zsend_interface_link_params(client, ifp);
+	}
 }