gossip: don't use hand-coded nested messages for getnodes array.

We can simply tell it 'nodes' is 'num_nodes*struct gossip_getnodes_entry'.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/gossip/gossip.c

@@ -442,20 +442,23 @@ static struct io_plan *release_peer(struct io_conn *conn, struct daemon *daemon,
 static struct io_plan *getnodes(struct io_conn *conn, struct daemon *daemon)
 {
 	tal_t *tmpctx = tal_tmpctx(daemon);
-	u8 *out, *reply = tal_arr(tmpctx, u8, 0);
+	u8 *out;
 	struct node *n;
 	struct node_map_iter i;
+	struct gossip_getnodes_entry *nodes;
+	size_t node_count = 0;
 
+	nodes = tal_arr(tmpctx, struct gossip_getnodes_entry, node_count);
 	n = node_map_first(daemon->rstate->nodes, &i);
 	while (n != NULL) {
-		struct gossip_getnodes_entry entry;
-		entry.nodeid = n->id;
-		entry.hostname = n->hostname;
-		entry.port = n->port;
-		towire_gossip_getnodes_entry(&reply, &entry);
+		tal_resize(&nodes, node_count + 1);
+		nodes[node_count].nodeid = n->id;
+		nodes[node_count].hostname = n->hostname;
+		nodes[node_count].port = n->port;
+		node_count++;
 		n = node_map_next(daemon->rstate->nodes, &i);
 	}
-	out = towire_gossip_getnodes_reply(daemon, reply);
+	out = towire_gossip_getnodes_reply(daemon, nodes);
 	tal_free(tmpctx);
 	return io_write_wire(conn, take(out), next_req_in, daemon);
 }

lightningd/gossip/gossip_wire.csv

@@ -50,6 +50,7 @@ gossipstatus_peer_nongossip,156,msg,len*u8
 # Pass JSON-RPC getnodes call through
 gossip_getnodes_request,5
 
+#include <lightningd/gossip_msg.h>
 gossip_getnodes_reply,105
-gossip_getnodes_reply,0,replen,u16
-gossip_getnodes_reply,2,reply,replen*u8
+gossip_getnodes_reply,0,num_nodes,u16
+gossip_getnodes_reply,2,nodes,num_nodes*struct gossip_getnodes_entry

lightningd/gossip_control.c

@@ -154,35 +154,32 @@ void gossip_init(struct lightningd *ld)
 static bool json_getnodes_reply(struct subd *gossip, const u8 *reply,
 				struct command *cmd)
 {
-	u8 *inner;
-	const u8 *cursor;
-	size_t max;
-
+	struct gossip_getnodes_entry *nodes;
 	struct json_result *response = new_json_result(cmd);
-	fromwire_gossip_getnodes_reply(reply, reply, NULL, &inner);
-	max = tal_len(inner);
-	cursor = inner;
+	size_t i;
+
+	if (!fromwire_gossip_getnodes_reply(reply, reply, NULL, &nodes)) {
+		command_fail(cmd, "Malformed gossip_getnodes response");
+		return true;
+	}
+
 	json_object_start(response, NULL);
 	json_array_start(response, "nodes");
 
-	while (max > 0) {
-		struct gossip_getnodes_entry *entry = tal(reply, struct gossip_getnodes_entry);
-		fromwire_gossip_getnodes_entry(&cursor, &max, entry);
+	for (i = 0; i < tal_count(nodes); i++) {
 		json_object_start(response, NULL);
-		json_add_pubkey(response, "nodeid", &entry->nodeid);
-		if (tal_len(entry->hostname) > 0) {
-			json_add_string(response, "hostname", entry->hostname);
+		json_add_pubkey(response, "nodeid", &nodes[i].nodeid);
+		if (tal_len(nodes[i].hostname) > 0) {
+			json_add_string(response, "hostname", nodes[i].hostname);
 		} else {
 			json_add_null(response, "hostname");
 		}
-		json_add_num(response, "port", entry->port);
+		json_add_num(response, "port", nodes[i].port);
 		json_object_end(response);
-		tal_free(entry);
 	}
 	json_array_end(response);
 	json_object_end(response);
 	command_success(cmd, response);
-	tal_free(reply);
 	return true;
 }