lightningd: tell gossipd when we use the channel_update.

This way it can flush it if it was pending.

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

gossipd/gossip_generation.c

@@ -811,6 +811,26 @@ void local_disable_chan(struct daemon *daemon, const struct chan *chan, int dire
 	defer_update(daemon, 0xFFFFFFFF, chan, direction, take(update));
 }
 
+/* lightningd tells us it used the local channel update. */
+void handle_used_local_channel_update(struct daemon *daemon, const u8 *msg)
+{
+	struct short_channel_id scid;
+	struct chan *chan;
+
+	if (!fromwire_gossipd_used_local_channel_update(msg, &scid))
+		master_badmsg(WIRE_GOSSIPD_USED_LOCAL_CHANNEL_UPDATE, msg);
+
+	chan = get_channel(daemon->rstate, &scid);
+	/* Might have closed in meantime, but v unlikely! */
+	if (!chan) {
+		status_broken("used_local_channel_update on unknown %s",
+			      type_to_string(tmpctx, struct short_channel_id,
+					     &scid));
+		return;
+	}
+	local_channel_update_latest(daemon, chan);
+}
+
 void local_enable_chan(struct daemon *daemon, const struct chan *chan, int direction)
 {
 	struct deferred_update *du;

gossipd/gossip_generation.h

@@ -53,4 +53,7 @@ bool handle_local_channel_update(struct daemon *daemon,
 				 const struct node_id *src,
 				 const u8 *msg);
 
+/* lightningd tells us it used the last channel_update we sent. */
+void handle_used_local_channel_update(struct daemon *daemon, const u8 *msg);
+
 #endif /* LIGHTNING_GOSSIPD_GOSSIP_GENERATION_H */

gossipd/gossipd.c

@@ -1413,6 +1413,10 @@ static struct io_plan *recv_req(struct io_conn *conn,
 	case WIRE_GOSSIPD_GET_ADDRS:
 		return handle_get_address(conn, daemon, msg);
 
+	case WIRE_GOSSIPD_USED_LOCAL_CHANNEL_UPDATE:
+		handle_used_local_channel_update(daemon, msg);
+		goto done;
+
 #if DEVELOPER
 	case WIRE_GOSSIPD_DEV_SET_MAX_SCIDS_ENCODE_SIZE:
 		dev_set_max_scids_encode_size(daemon, msg);

gossipd/gossipd_wire.csv

@@ -122,3 +122,7 @@ msgtype,gossipd_got_local_channel_update,3151
 msgdata,gossipd_got_local_channel_update,scid,short_channel_id,
 msgdata,gossipd_got_local_channel_update,len,u16,
 msgdata,gossipd_got_local_channel_update,channel_update,u8,len
+
+# Tell gossipd we used the channel update (in case it was deferred)
+msgtype,gossipd_used_local_channel_update,3052
+msgdata,gossipd_used_local_channel_update,scid,short_channel_id,

gossipd/test/run-check_node_announcement.c

@@ -39,6 +39,9 @@ char *fmt_wireaddr_without_port(const tal_t *ctx UNNEEDED, const struct wireaddr
 /* Generated stub for fromwire_gossipd_local_channel_update */
 bool fromwire_gossipd_local_channel_update(const void *p UNNEEDED, struct short_channel_id *short_channel_id UNNEEDED, bool *disable UNNEEDED, u16 *cltv_expiry_delta UNNEEDED, struct amount_msat *htlc_minimum_msat UNNEEDED, u32 *fee_base_msat UNNEEDED, u32 *fee_proportional_millionths UNNEEDED, struct amount_msat *htlc_maximum_msat UNNEEDED)
 { fprintf(stderr, "fromwire_gossipd_local_channel_update called!\n"); abort(); }
+/* Generated stub for fromwire_gossipd_used_local_channel_update */
+bool fromwire_gossipd_used_local_channel_update(const void *p UNNEEDED, struct short_channel_id *scid UNNEEDED)
+{ fprintf(stderr, "fromwire_gossipd_used_local_channel_update called!\n"); abort(); }
 /* Generated stub for fromwire_hsmd_cupdate_sig_reply */
 bool fromwire_hsmd_cupdate_sig_reply(const tal_t *ctx UNNEEDED, const void *p UNNEEDED, u8 **cu UNNEEDED)
 { fprintf(stderr, "fromwire_hsmd_cupdate_sig_reply called!\n"); abort(); }
@@ -78,6 +81,9 @@ void json_object_end(struct json_stream *js UNNEEDED)
 /* Generated stub for json_object_start */
 void json_object_start(struct json_stream *ks UNNEEDED, const char *fieldname UNNEEDED)
 { fprintf(stderr, "json_object_start called!\n"); abort(); }
+/* Generated stub for master_badmsg */
+void master_badmsg(u32 type_expected UNNEEDED, const u8 *msg)
+{ fprintf(stderr, "master_badmsg called!\n"); abort(); }
 /* Generated stub for new_onionreply */
 struct onionreply *new_onionreply(const tal_t *ctx UNNEEDED, const u8 *contents TAKES UNNEEDED)
 { fprintf(stderr, "new_onionreply called!\n"); abort(); }

gossipd/test/run-crc32_of_update.c

@@ -60,6 +60,9 @@ bool fromwire_gossipd_dev_set_max_scids_encode_size(const void *p UNNEEDED, u32
 /* Generated stub for fromwire_gossipd_local_channel_update */
 bool fromwire_gossipd_local_channel_update(const void *p UNNEEDED, struct short_channel_id *short_channel_id UNNEEDED, bool *disable UNNEEDED, u16 *cltv_expiry_delta UNNEEDED, struct amount_msat *htlc_minimum_msat UNNEEDED, u32 *fee_base_msat UNNEEDED, u32 *fee_proportional_millionths UNNEEDED, struct amount_msat *htlc_maximum_msat UNNEEDED)
 { fprintf(stderr, "fromwire_gossipd_local_channel_update called!\n"); abort(); }
+/* Generated stub for fromwire_gossipd_used_local_channel_update */
+bool fromwire_gossipd_used_local_channel_update(const void *p UNNEEDED, struct short_channel_id *scid UNNEEDED)
+{ fprintf(stderr, "fromwire_gossipd_used_local_channel_update called!\n"); abort(); }
 /* Generated stub for fromwire_hsmd_cupdate_sig_reply */
 bool fromwire_hsmd_cupdate_sig_reply(const tal_t *ctx UNNEEDED, const void *p UNNEEDED, u8 **cu UNNEEDED)
 { fprintf(stderr, "fromwire_hsmd_cupdate_sig_reply called!\n"); abort(); }

gossipd/test/run-onion_message.c

@@ -183,6 +183,9 @@ const u8 *handle_reply_channel_range(struct peer *peer UNNEEDED, const u8 *msg U
 /* Generated stub for handle_reply_short_channel_ids_end */
 const u8 *handle_reply_short_channel_ids_end(struct peer *peer UNNEEDED, const u8 *msg UNNEEDED)
 { fprintf(stderr, "handle_reply_short_channel_ids_end called!\n"); abort(); }
+/* Generated stub for handle_used_local_channel_update */
+void handle_used_local_channel_update(struct daemon *daemon UNNEEDED, const u8 *msg UNNEEDED)
+{ fprintf(stderr, "handle_used_local_channel_update called!\n"); abort(); }
 /* Generated stub for json_add_member */
 void json_add_member(struct json_stream *js UNNEEDED,
 		     const char *fieldname UNNEEDED,

lightningd/channel.h

@@ -474,4 +474,6 @@ void channel_set_billboard(struct channel *channel, bool perm,
 struct htlc_in *channel_has_htlc_in(struct channel *channel);
 struct htlc_out *channel_has_htlc_out(struct channel *channel);
 
+const u8 *get_channel_update(struct channel *channel);
+
 #endif /* LIGHTNING_LIGHTNINGD_CHANNEL_H */

lightningd/gossip_control.c

@@ -135,6 +135,17 @@ static void handle_local_channel_update(struct lightningd *ld, const u8 *msg)
 	channel->channel_update = tal_steal(channel, update);
 }
 
+const u8 *get_channel_update(struct channel *channel)
+{
+	/* Tell gossipd we're using it (if shutting down, might be NULL) */
+	if (channel->channel_update && channel->peer->ld->gossip) {
+		subd_send_msg(channel->peer->ld->gossip,
+			      take(towire_gossipd_used_local_channel_update
+				   (NULL, channel->scid)));
+	}
+	return channel->channel_update;
+}
+
 static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 {
 	enum gossipd_wire t = fromwire_peektype(msg);
@@ -156,6 +167,7 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 	case WIRE_GOSSIPD_SEND_ONIONMSG:
 	case WIRE_GOSSIPD_ADDGOSSIP:
 	case WIRE_GOSSIPD_GET_ADDRS:
+	case WIRE_GOSSIPD_USED_LOCAL_CHANNEL_UPDATE:
 	/* This is a reply, so never gets through to here. */
 	case WIRE_GOSSIPD_INIT_REPLY:
 	case WIRE_GOSSIPD_DEV_MEMLEAK_REPLY: