bgpd, lib: Indicate when we are buffering instead of immediately sending down ZAPI

When FRR sends data over the ZAPI protocol from the upper levels to zebra, indicate
to the calling functions that we have started buffering data to be sent if the
socket is full underneath it.

Also add a call back function `zebra_buffer_write_ready` that we can call
when an upper level protocol's socket buffer has been drained.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

1 files changed, 34 insertions, 37 deletions

diff --git a/lib/zclient.c b/lib/zclient.c
index b27e2cef73..980ecc5ed8 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -277,11 +277,18 @@ static int zclient_flush_data(struct thread *thread)
 				 zclient->sock, &zclient->t_write);
 		break;
 	case BUFFER_EMPTY:
+		if (zclient->zebra_buffer_write_ready)
+			(*zclient->zebra_buffer_write_ready)();
 		break;
 	}
 	return 0;
 }
 
+/*
+ * -1 is a failure
+ *  0 means we sent
+ *  1 means we are buffering
+ */
 int zclient_send_message(struct zclient *zclient)
 {
 	if (zclient->sock < 0)
@@ -296,12 +303,16 @@ int zclient_send_message(struct zclient *zclient)
 		return zclient_failed(zclient);
 	case BUFFER_EMPTY:
 		THREAD_OFF(zclient->t_write);
+		return 0;
 		break;
 	case BUFFER_PENDING:
 		thread_add_write(zclient->master, zclient_flush_data, zclient,
 				 zclient->sock, &zclient->t_write);
+		return 1;
 		break;
 	}
+
+	/* should not get here */
 	return 0;
 }
 
@@ -406,8 +417,8 @@ int zclient_send_hello(struct zclient *zclient)
 	return 0;
 }
 
-void zclient_send_vrf_label(struct zclient *zclient, vrf_id_t vrf_id, afi_t afi,
-			    mpls_label_t label, enum lsp_types_t ltype)
+int zclient_send_vrf_label(struct zclient *zclient, vrf_id_t vrf_id, afi_t afi,
+			   mpls_label_t label, enum lsp_types_t ltype)
 {
 	struct stream *s;
 
@@ -419,7 +430,7 @@ void zclient_send_vrf_label(struct zclient *zclient, vrf_id_t vrf_id, afi_t afi,
 	stream_putc(s, afi);
 	stream_putc(s, ltype);
 	stream_putw_at(s, 0, stream_get_endp(s));
-	zclient_send_message(zclient);
+	return zclient_send_message(zclient);
 }
 
 /* Send register requests to zebra daemon for the information in a VRF. */
@@ -570,15 +581,15 @@ int zclient_send_router_id_update(struct zclient *zclient,
 }
 
 /* Send request to zebra daemon to start or stop RA. */
-void zclient_send_interface_radv_req(struct zclient *zclient, vrf_id_t vrf_id,
-				     struct interface *ifp, int enable,
-				     int ra_interval)
+int zclient_send_interface_radv_req(struct zclient *zclient, vrf_id_t vrf_id,
+				    struct interface *ifp, int enable,
+				    int ra_interval)
 {
 	struct stream *s;
 
 	/* If not connected to the zebra yet. */
 	if (zclient->sock < 0)
-		return;
+		return -1;
 
 	/* Form and send message. */
 	s = zclient->obuf;
@@ -594,7 +605,7 @@ void zclient_send_interface_radv_req(struct zclient *zclient, vrf_id_t vrf_id,
 
 	stream_putw_at(s, 0, stream_get_endp(s));
 
-	zclient_send_message(zclient);
+	return zclient_send_message(zclient);
 }
 
 int zclient_send_interface_protodown(struct zclient *zclient, vrf_id_t vrf_id,
@@ -611,9 +622,7 @@ int zclient_send_interface_protodown(struct zclient *zclient, vrf_id_t vrf_id,
 	stream_putl(s, ifp->ifindex);
 	stream_putc(s, !!down);
 	stream_putw_at(s, 0, stream_get_endp(s));
-	zclient_send_message(zclient);
-
-	return 0;
+	return zclient_send_message(zclient);
 }
 
 /* Make connection to zebra daemon. */
@@ -3281,7 +3290,7 @@ stream_failure:
 	return;
 }
 
-void zclient_send_mlag_register(struct zclient *client, uint32_t bit_map)
+int zclient_send_mlag_register(struct zclient *client, uint32_t bit_map)
 {
 	struct stream *s;
 
@@ -3292,15 +3301,15 @@ void zclient_send_mlag_register(struct zclient *client, uint32_t bit_map)
 	stream_putl(s, bit_map);
 
 	stream_putw_at(s, 0, stream_get_endp(s));
-	zclient_send_message(client);
+	return zclient_send_message(client);
 }
 
-void zclient_send_mlag_deregister(struct zclient *client)
+int zclient_send_mlag_deregister(struct zclient *client)
 {
-	zebra_message_send(client, ZEBRA_MLAG_CLIENT_UNREGISTER, VRF_DEFAULT);
+	return zebra_message_send(client, ZEBRA_MLAG_CLIENT_UNREGISTER, VRF_DEFAULT);
 }
 
-void zclient_send_mlag_data(struct zclient *client, struct stream *client_s)
+int zclient_send_mlag_data(struct zclient *client, struct stream *client_s)
 {
 	struct stream *s;
 
@@ -3311,7 +3320,7 @@ void zclient_send_mlag_data(struct zclient *client, struct stream *client_s)
 	stream_put(s, client_s->data, client_s->endp);
 
 	stream_putw_at(s, 0, stream_get_endp(s));
-	zclient_send_message(client);
+	return zclient_send_message(client);
 }
 
 static void zclient_mlag_process_up(ZAPI_CALLBACK_ARGS)
@@ -3339,7 +3348,6 @@ static void zclient_mlag_handle_msg(ZAPI_CALLBACK_ARGS)
 int zclient_send_opaque(struct zclient *zclient, uint32_t type,
 			const uint8_t *data, size_t datasize)
 {
-	int ret;
 	struct stream *s;
 	uint16_t flags = 0;
 
@@ -3363,9 +3371,7 @@ int zclient_send_opaque(struct zclient *zclient, uint32_t type,
 	/* Put length into the header at the start of the stream. */
 	stream_putw_at(s, 0, stream_get_endp(s));
 
-	ret = zclient_send_message(zclient);
-
-	return ret;
+	return zclient_send_message(zclient);
 }
 
 /*
@@ -3377,7 +3383,6 @@ int zclient_send_opaque_unicast(struct zclient *zclient, uint32_t type,
 				uint32_t session_id, const uint8_t *data,
 				size_t datasize)
 {
-	int ret;
 	struct stream *s;
 	uint16_t flags = 0;
 
@@ -3407,9 +3412,7 @@ int zclient_send_opaque_unicast(struct zclient *zclient, uint32_t type,
 	/* Put length into the header at the start of the stream. */
 	stream_putw_at(s, 0, stream_get_endp(s));
 
-	ret = zclient_send_message(zclient);
-
-	return ret;
+	return zclient_send_message(zclient);
 }
 
 /*
@@ -3444,7 +3447,6 @@ stream_failure:
  */
 int zclient_register_opaque(struct zclient *zclient, uint32_t type)
 {
-	int ret;
 	struct stream *s;
 
 	s = zclient->obuf;
@@ -3463,9 +3465,7 @@ int zclient_register_opaque(struct zclient *zclient, uint32_t type)
 	/* Put length at the first point of the stream. */
 	stream_putw_at(s, 0, stream_get_endp(s));
 
-	ret = zclient_send_message(zclient);
-
-	return ret;
+	return zclient_send_message(zclient);
 }
 
 /*
@@ -3473,7 +3473,6 @@ int zclient_register_opaque(struct zclient *zclient, uint32_t type)
  */
 int zclient_unregister_opaque(struct zclient *zclient, uint32_t type)
 {
-	int ret;
 	struct stream *s;
 
 	s = zclient->obuf;
@@ -3492,9 +3491,7 @@ int zclient_unregister_opaque(struct zclient *zclient, uint32_t type)
 	/* Put length at the first point of the stream. */
 	stream_putw_at(s, 0, stream_get_endp(s));
 
-	ret = zclient_send_message(zclient);
-
-	return ret;
+	return zclient_send_message(zclient);
 }
 
 /* Utility to decode opaque registration info */
@@ -3949,9 +3946,9 @@ static void zclient_event(enum event event, struct zclient *zclient)
 	}
 }
 
-void zclient_interface_set_master(struct zclient *client,
-				  struct interface *master,
-				  struct interface *slave)
+int zclient_interface_set_master(struct zclient *client,
+				 struct interface *master,
+				 struct interface *slave)
 {
 	struct stream *s;
 
@@ -3966,7 +3963,7 @@ void zclient_interface_set_master(struct zclient *client,
 	stream_putl(s, slave->ifindex);
 
 	stream_putw_at(s, 0, stream_get_endp(s));
-	zclient_send_message(client);
+	return zclient_send_message(client);
 }
 
 /*