gossipd: batch outpoints spent, add block height.

It's a bit more optimal, and tells gossipd exactly what height the
spend occurred at (with multiple blocks, it's not always the current
height!).  It will need that next patch.

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

gossipd/gossipd.c

@@ -927,22 +927,27 @@ static void handle_new_lease_rates(struct daemon *daemon, const u8 *msg)
 
 /*~ This is where lightningd tells us that a channel's funding transaction has
  * been spent. */
-static void handle_outpoint_spent(struct daemon *daemon, const u8 *msg)
+static void handle_outpoints_spent(struct daemon *daemon, const u8 *msg)
 {
-	struct short_channel_id scid;
-	struct chan *chan;
+	struct short_channel_id *scids;
+	u32 blockheight;
 	struct routing_state *rstate = daemon->rstate;
-	if (!fromwire_gossipd_outpoint_spent(msg, &scid))
-		master_badmsg(WIRE_GOSSIPD_OUTPOINT_SPENT, msg);
 
-	chan = get_channel(rstate, &scid);
-	if (chan) {
+	if (!fromwire_gossipd_outpoints_spent(msg, msg, &blockheight, &scids))
+		master_badmsg(WIRE_GOSSIPD_OUTPOINTS_SPENT, msg);
+
+	for (size_t i = 0; i < tal_count(scids); i++) {
+		struct chan *chan = get_channel(rstate, &scids[i]);
+
+		if (!chan)
+			continue;
+
 		status_debug(
 		    "Deleting channel %s due to the funding outpoint being "
 		    "spent",
-		    type_to_string(msg, struct short_channel_id, &scid));
+		    type_to_string(msg, struct short_channel_id, &scids[i]));
 		/* Suppress any now-obsolete updates/announcements */
-		add_to_txout_failures(rstate, &scid);
+		add_to_txout_failures(rstate, &scids[i]);
 		remove_channel_from_store(rstate, chan);
 		/* Freeing is sufficient since everything else is allocated off
 		 * of the channel and this takes care of unregistering
@@ -999,8 +1004,8 @@ static struct io_plan *recv_req(struct io_conn *conn,
 		handle_txout_reply(daemon, msg);
 		goto done;
 
-	case WIRE_GOSSIPD_OUTPOINT_SPENT:
-		handle_outpoint_spent(daemon, msg);
+	case WIRE_GOSSIPD_OUTPOINTS_SPENT:
+		handle_outpoints_spent(daemon, msg);
 		goto done;
 
 	case WIRE_GOSSIPD_LOCAL_CHANNEL_CLOSE:

gossipd/gossipd_wire.csv

@@ -42,9 +42,11 @@ msgdata,gossipd_get_txout_reply,satoshis,amount_sat,
 msgdata,gossipd_get_txout_reply,len,u16,
 msgdata,gossipd_get_txout_reply,outscript,u8,len
 
-# master -> gossipd: a potential funding outpoint was spent, please forget the eventual channel
-msgtype,gossipd_outpoint_spent,3024
-msgdata,gossipd_outpoint_spent,short_channel_id,short_channel_id,
+# master -> gossipd: these potential funding outpoints were spent, please forget any channels
+msgtype,gossipd_outpoints_spent,3024
+msgdata,gossipd_outpoints_spent,blockheight,u32,
+msgdata,gossipd_outpoints_spent,len,u32,
+msgdata,gossipd_outpoints_spent,short_channel_id,short_channel_id,len
 
 # master -> gossipd: do you have a memleak?
 msgtype,gossipd_dev_memleak,3033

lightningd/chaintopology.c

@@ -682,11 +682,7 @@ static void topo_update_spends(struct chain_topology *topo, struct block *b)
 	 * tell gossipd about them. */
 	spent_scids =
 	    wallet_utxoset_get_spent(tmpctx, topo->ld->wallet, b->height);
-
-	for (size_t i=0; i<tal_count(spent_scids); i++) {
-		gossipd_notify_spend(topo->bitcoind->ld, &spent_scids[i]);
-	}
-	tal_free(spent_scids);
+	gossipd_notify_spends(topo->bitcoind->ld, b->height, spent_scids);
 }
 
 static void topo_add_utxos(struct chain_topology *topo, struct block *b)
@@ -792,12 +788,11 @@ static void remove_tip(struct chain_topology *topo)
 	/* This may have unconfirmed txs: reconfirm as we add blocks. */
 	watch_for_utxo_reconfirmation(topo, topo->ld->wallet);
 	block_map_del(&topo->block_map, b);
-	tal_free(b);
 
 	/* These no longer exist, so gossipd drops any reference to them just
 	 * as if they were spent. */
-	for (size_t i = 0; i < tal_count(removed_scids); i++)
-		gossipd_notify_spend(topo->bitcoind->ld, &removed_scids[i]);
+	gossipd_notify_spends(topo->bitcoind->ld, b->height, removed_scids);
+	tal_free(b);
 }
 
 static void get_new_block(struct bitcoind *bitcoind,

lightningd/gossip_control.c

@@ -153,7 +153,7 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 	/* These are messages we send, not them. */
 	case WIRE_GOSSIPD_INIT:
 	case WIRE_GOSSIPD_GET_TXOUT_REPLY:
-	case WIRE_GOSSIPD_OUTPOINT_SPENT:
+	case WIRE_GOSSIPD_OUTPOINTS_SPENT:
 	case WIRE_GOSSIPD_NEW_LEASE_RATES:
 	case WIRE_GOSSIPD_DEV_SET_MAX_SCIDS_ENCODE_SIZE:
 	case WIRE_GOSSIPD_LOCAL_CHANNEL_CLOSE:
@@ -273,11 +273,15 @@ void gossip_init(struct lightningd *ld, int connectd_fd)
 	assert(ret == ld->gossip);
 }
 
-void gossipd_notify_spend(struct lightningd *ld,
-			  const struct short_channel_id *scid)
+/* We save these so we always tell gossipd about new blockheight first. */
+void gossipd_notify_spends(struct lightningd *ld,
+			   u32 blockheight,
+			   const struct short_channel_id *scids)
 {
-	u8 *msg = towire_gossipd_outpoint_spent(tmpctx, scid);
-	subd_send_msg(ld->gossip, msg);
+	subd_send_msg(ld->gossip,
+		      take(towire_gossipd_outpoints_spent(NULL,
+							  blockheight,
+							  scids)));
 }
 
 /* We unwrap, add the peer id, and send to gossipd. */

lightningd/gossip_control.h

@@ -10,8 +10,9 @@ struct lightningd;
 
 void gossip_init(struct lightningd *ld, int connectd_fd);
 
-void gossipd_notify_spend(struct lightningd *ld,
-			  const struct short_channel_id *scid);
+void gossipd_notify_spends(struct lightningd *ld,
+			   u32 blockheight,
+			   const struct short_channel_id *scids);
 
 void gossip_notify_new_block(struct lightningd *ld, u32 blockheight);