gossipd: tell lightningd about all our previous channel_updates at startup

gossipd/gossipd.c

@@ -747,6 +747,42 @@ static void gossip_refresh_network(struct daemon *daemon)
 	route_prune(daemon->rstate);
 }
 
+static void tell_master_local_cupdates(struct daemon *daemon)
+{
+	struct chan_map_iter i;
+	struct chan *c;
+	struct node *me;
+
+	me = get_node(daemon->rstate, &daemon->id);
+	if (!me)
+		return;
+
+	for (c = first_chan(me, &i); c; c = next_chan(me, &i)) {
+		struct half_chan *hc;
+		int direction;
+		const u8 *cupdate;
+
+		/* We don't provide update_channel for unannounced channels */
+		if (!is_chan_public(c))
+			continue;
+
+		if (!local_direction(daemon->rstate, c, &direction))
+			continue;
+
+		hc = &c->half[direction];
+		if (!is_halfchan_defined(hc))
+			continue;
+
+		cupdate = gossip_store_get(tmpctx,
+					   daemon->rstate->gs,
+					   hc->bcast.index);
+		daemon_conn_send(daemon->master,
+				 take(towire_gossipd_init_cupdate(NULL,
+								  &c->scid,
+								  cupdate)));
+	}
+}
+
 /* Disables all channels connected to our node. */
 static void gossip_disable_local_channels(struct daemon *daemon)
 {
@@ -851,6 +887,10 @@ static void gossip_init(struct daemon *daemon, const u8 *msg)
 					   maybe_send_query_responses, daemon);
 	tal_add_destructor(daemon->connectd, master_or_connectd_gone);
 
+	/* Tell it about all our local (public) channel_update messages,
+	 * so it doesn't unnecessarily regenerate them. */
+	tell_master_local_cupdates(daemon);
+
 	/* OK, we are ready. */
 	daemon_conn_send(daemon->master,
 			 take(towire_gossipd_init_reply(NULL)));
@@ -1143,6 +1183,7 @@ static struct io_plan *recv_req(struct io_conn *conn,
 #endif /* !DEVELOPER */
 
 	/* We send these, we don't receive them */
+	case WIRE_GOSSIPD_INIT_CUPDATE:
 	case WIRE_GOSSIPD_INIT_REPLY:
 	case WIRE_GOSSIPD_GET_TXOUT:
 	case WIRE_GOSSIPD_DEV_MEMLEAK_REPLY:

gossipd/gossipd_wire.csv

@@ -18,6 +18,12 @@ msgdata,gossipd_init,dev_fast_gossip,bool,
 msgdata,gossipd_init,dev_fast_gossip_prune,bool,
 msgdata,gossipd_init,ip_discovery,u32,
 
+# Gossipd tells us all our public channel_updates before init_reply.
+msgtype,gossipd_init_cupdate,3101
+msgdata,gossipd_init_cupdate,scid,short_channel_id,
+msgdata,gossipd_init_cupdate,len,u16,
+msgdata,gossipd_init_cupdate,cupdate,u8,len
+
 msgtype,gossipd_init_reply,3100
 
 # In developer mode, we can mess with time.

lightningd/gossip_control.c

@@ -109,6 +109,33 @@ static void get_txout(struct subd *gossip, const u8 *msg)
 	}
 }
 
+static void handle_init_cupdate(struct lightningd *ld, const u8 *msg)
+{
+	struct short_channel_id scid;
+	u8 *update;
+	struct channel *channel;
+
+	if (!fromwire_gossipd_init_cupdate(msg, msg, &scid, &update)) {
+		fatal("Gossip gave bad GOSSIPD_INIT_CUPDATE %s",
+		      tal_hex(msg, msg));
+	}
+
+	/* In theory this could vanish before gossipd gets around to telling
+	 * us. */
+	channel = any_channel_by_scid(ld, &scid, true);
+	if (!channel) {
+		log_unusual(ld->log, "init_cupdate for bad scid %s",
+			    type_to_string(tmpctx, struct short_channel_id,
+					   &scid));
+		return;
+	}
+
+	/* This should only happen on initialization, *but* gossipd also
+	 * disabled channels on startup, so that can set this first. */
+	if (!channel->channel_update)
+		channel->channel_update = tal_steal(channel, update);
+}
+
 static void handle_local_channel_update(struct lightningd *ld, const u8 *msg)
 {
 	struct short_channel_id scid;
@@ -177,6 +204,9 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 	case WIRE_GOSSIPD_DISCOVERED_IP:
 		break;
 
+	case WIRE_GOSSIPD_INIT_CUPDATE:
+		handle_init_cupdate(gossip->ld, msg);
+		break;
 	case WIRE_GOSSIPD_GET_TXOUT:
 		get_txout(gossip, msg);
 		break;