gossip: Implemented `getnodes` JSON-RPC call

lightningd/gossip/gossip.c

@@ -20,6 +20,7 @@
 #include <lightningd/cryptomsg.h>
 #include <lightningd/debug.h>
 #include <lightningd/gossip/gen_gossip_wire.h>
+#include <lightningd/gossip_msg.h>
 #include <secp256k1_ecdh.h>
 #include <sodium/randombytes.h>
 #include <status.h>
@@ -438,6 +439,27 @@ static struct io_plan *release_peer(struct io_conn *conn, struct daemon *daemon,
 		      "Unknown peer %"PRIu64, unique_id);
 }
 
+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);
+	struct node *n;
+	struct node_map_iter i;
+
+	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);
+		n = node_map_next(daemon->rstate->nodes, &i);
+	}
+	out = towire_gossip_getnodes_reply(daemon, reply);
+	tal_free(tmpctx);
+	return io_write_wire(conn, take(out), next_req_in, daemon);
+}
+
 static struct io_plan *recv_req(struct io_conn *conn, struct daemon *daemon)
 {
 	enum gossip_wire_type t = fromwire_peektype(daemon->msg_in);
@@ -451,7 +473,11 @@ static struct io_plan *recv_req(struct io_conn *conn, struct daemon *daemon)
 	case WIRE_GOSSIPCTL_RELEASE_PEER:
 		return release_peer(conn, daemon, daemon->msg_in);
 
+	case WIRE_GOSSIP_GETNODES_REQUEST:
+		return getnodes(conn, daemon);
+
 	case WIRE_GOSSIPCTL_RELEASE_PEER_REPLY:
+	case WIRE_GOSSIP_GETNODES_REPLY:
 	case WIRE_GOSSIPSTATUS_INIT_FAILED:
 	case WIRE_GOSSIPSTATUS_BAD_NEW_PEER_REQUEST:
 	case WIRE_GOSSIPSTATUS_BAD_RELEASE_REQUEST:

lightningd/gossip/gossip_wire.csv

@@ -46,3 +46,10 @@ gossipstatus_peer_nongossip,0,unique_id,8
 gossipstatus_peer_nongossip,10,crypto_state,144,struct crypto_state
 gossipstatus_peer_nongossip,154,len,2
 gossipstatus_peer_nongossip,156,msg,len,u8
+
+# Pass JSON-RPC getnodes call through
+gossip_getnodes_request,5
+
+gossip_getnodes_reply,105
+gossip_getnodes_reply,0,replen,2,u16
+gossip_getnodes_reply,2,reply,replen,u8

lightningd/gossip_control.c

@@ -9,6 +9,7 @@
 #include <inttypes.h>
 #include <lightningd/cryptomsg.h>
 #include <lightningd/gossip/gen_gossip_wire.h>
+#include <lightningd/gossip_msg.h>
 #include <wire/gen_peer_wire.h>
 
 static void gossip_finished(struct subd *gossip, int status)
@@ -118,8 +119,10 @@ static enum subd_msg_ret gossip_msg(struct subd *gossip,
 	/* These are messages we send, not them. */
 	case WIRE_GOSSIPCTL_NEW_PEER:
 	case WIRE_GOSSIPCTL_RELEASE_PEER:
+	case WIRE_GOSSIP_GETNODES_REQUEST:
 	/* This is a reply, so never gets through to here. */
 	case WIRE_GOSSIPCTL_RELEASE_PEER_REPLY:
+	case WIRE_GOSSIP_GETNODES_REPLY:
 		break;
 	case WIRE_GOSSIPSTATUS_PEER_BAD_MSG:
 		peer_bad_message(gossip, msg);
@@ -147,3 +150,51 @@ void gossip_init(struct lightningd *ld)
 	if (!ld->gossip)
 		err(1, "Could not subdaemon gossip");
 }
+
+static bool json_getnodes_reply(struct subd *gossip, const u8 *reply,
+				struct command *cmd)
+{
+	u8 *inner;
+	const u8 *cursor;
+	size_t max;
+
+	struct json_result *response = new_json_result(cmd);
+	fromwire_gossip_getnodes_reply(reply, reply, NULL, &inner);
+	max = tal_len(inner);
+	cursor = inner;
+	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);
+		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);
+		} else {
+			json_add_null(response, "hostname");
+		}
+		json_add_num(response, "port", entry->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;
+}
+
+static void json_getnodes(struct command *cmd, const char *buffer,
+			  const jsmntok_t *params)
+{
+	struct lightningd *ld = ld_from_dstate(cmd->dstate);
+	u8 *req = towire_gossip_getnodes_request(cmd);
+	subd_req(ld->gossip, req, -1, NULL, json_getnodes_reply, cmd);
+}
+
+static const struct json_command getnodes_command = {
+    "getnodes", json_getnodes, "Retrieve all nodes in our local network view",
+    "Returns a list of all nodes that we know about"};
+AUTODATA(json_command, &getnodes_command);