lib, zebra: use existing zapi header struct

Nobody uses it, but it's got the same definition. Move the parser
function into zclient.c and use it.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

lib/zclient.c

@@ -322,6 +322,18 @@ int zclient_read_header(struct stream *s, int sock, u_int16_t *size,
 	return 0;
 }
 
+bool zapi_parse_header(struct stream *zmsg, struct zmsghdr *hdr)
+{
+	STREAM_GETW(zmsg, hdr->length);
+	STREAM_GETC(zmsg, hdr->marker);
+	STREAM_GETC(zmsg, hdr->version);
+	STREAM_GETC(zmsg, hdr->vrf_id);
+	STREAM_GETW(zmsg, hdr->command);
+	return true;
+stream_failure:
+	return false;
+}
+
 /* Send simple Zebra message. */
 static int zebra_message_send(struct zclient *zclient, int command,
 			      vrf_id_t vrf_id)

lib/zclient.h

@@ -226,14 +226,14 @@ struct zclient {
 #define ZAPI_MESSAGE_SRCPFX   0x20
 #define ZAPI_MESSAGE_LABEL    0x40
 
+#define ZSERV_VERSION	5
 /* Zserv protocol message header */
-struct zserv_header {
+struct zmsghdr {
 	uint16_t length;
-	uint8_t marker; /* corresponds to command field in old zserv
-			 * always set to 255 in new zserv.
-			 */
+	/* corresponds to command field in old zserv
+	 * always set to 255 in new zserv. */
+	uint8_t marker;
 	uint8_t version;
-#define ZSERV_VERSION	5
 	vrf_id_t vrf_id;
 	uint16_t command;
 };
@@ -428,9 +428,58 @@ extern int zclient_send_message(struct zclient *);
 
 /* create header for command, length to be filled in by user later */
 extern void zclient_create_header(struct stream *, uint16_t, vrf_id_t);
+/*
+ * Read sizeof(struct zmsghdr) bytes from the provided socket and parse the
+ * received data into the specified fields. If this is successful, read the
+ * rest of the packet into the provided stream.
+ *
+ * s
+ *    The stream to read into
+ *
+ * sock
+ *    The socket to read from
+ *
+ * size
+ *    Parsed message size will be placed in the pointed-at integer
+ *
+ * marker
+ *    Parsed marker will be placed in the pointed-at byte
+ *
+ * version
+ *    Parsed version will be placed in the pointed-at byte
+ *
+ * vrf_id
+ *    Parsed VRF ID will be placed in the pointed-at vrf_id_t
+ *
+ * cmd
+ *    Parsed command number will be placed in the pointed-at integer
+ *
+ * Returns:
+ *    -1 if:
+ *    - insufficient data for header was read
+ *    - a version mismatch was detected
+ *    - a marker mismatch was detected
+ *    - header size field specified more data than could be read
+ */
 extern int zclient_read_header(struct stream *s, int sock, u_int16_t *size,
 			       u_char *marker, u_char *version,
 			       vrf_id_t *vrf_id, u_int16_t *cmd);
+/*
+ * Parse header from ZAPI message stream into struct zmsghdr.
+ * This function assumes the stream getp points at the first byte of the header.
+ * If the function is successful then the stream getp will point to the byte
+ * immediately after the last byte of the header.
+ *
+ * zmsg
+ *    The stream containing the header
+ *
+ * hdr
+ *    The header struct to parse into.
+ *
+ * Returns:
+ *    true if parsing succeeded, false otherwise
+ */
+extern bool zapi_parse_header(struct stream *zmsg, struct zmsghdr *hdr);
 
 extern void zclient_interface_set_master(struct zclient *client,
 					 struct interface *master,
@@ -448,8 +497,7 @@ extern void zebra_interface_if_set_value(struct stream *, struct interface *);
 extern void zebra_router_id_update_read(struct stream *s, struct prefix *rid);
 
 #if CONFDATE > 20180823
-CPP_NOTICE(
-	"zapi_ipv4_route, zapi_ipv6_route, zapi_ipv4_route_ipv6_nexthop as well as the zapi_ipv4 and zapi_ipv6 data structures should be removed now");
+CPP_NOTICE("zapi_ipv4_route, zapi_ipv6_route, zapi_ipv4_route_ipv6_nexthop as well as the zapi_ipv4 and zapi_ipv6 data structures should be removed now");
 #endif
 
 extern int zapi_ipv4_route(u_char, struct zclient *, struct prefix_ipv4 *,

zebra/zebra_vxlan.c

@@ -6612,7 +6612,7 @@ void zebra_vxlan_advertise_gw_macip(ZAPI_HANDLER_ARGS)
 
 		zvni = zvni_lookup(vni);
 		if (!zvni)
-			return 0;
+			return;
 
 		if (IS_ZEBRA_DEBUG_VXLAN)
 			zlog_debug(

zebra/zserv.h

@@ -132,15 +132,6 @@ struct zserv {
 	int last_write_cmd;
 };
 
-/* ZAPI protocol structs */
-struct zmsghdr {
-	uint16_t length;
-	uint8_t marker;
-	uint8_t version;
-	uint32_t vrf_id;
-	uint16_t command;
-};
-
 #define ZAPI_HANDLER_ARGS                                                      \
 	struct zserv *client, struct zmsghdr *hdr, struct stream *msg,         \
 		struct zebra_vrf *zvrf