gossipd: don't mark channels unroutable.

For transient failures, the pay plugin should simply exclude those
from route considerations.

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

gossipd/gossip_wire.csv

@@ -126,11 +126,6 @@ gossip_routing_failure,,failcode,u16
 gossip_routing_failure,,len,u16
 gossip_routing_failure,,channel_update,len*u8
 
-# master->gossipd temporarily mark a channel unroutable
-# (used in case of unparseable onion reply)
-gossip_mark_channel_unroutable,3022
-gossip_mark_channel_unroutable,,channel,struct short_channel_id
-
 # master -> gossipd: a potential funding outpoint was spent, please forget the eventual channel
 gossip_outpoint_spent,3024
 gossip_outpoint_spent,,short_channel_id,struct short_channel_id

gossipd/gossipd.c

@@ -2540,24 +2540,6 @@ static struct io_plan *handle_routing_failure(struct io_conn *conn,
 	return daemon_conn_read_next(conn, daemon->master);
 }
 
-/*~ This allows lightningd to explicitly mark a channel temporarily unroutable.
- * This is used when we get an unparsable error, and we don't know who to blame;
- * lightningd uses this to marking routes unroutable at random... */
-static struct io_plan *
-handle_mark_channel_unroutable(struct io_conn *conn,
-			       struct daemon *daemon,
-			       const u8 *msg)
-{
-	struct short_channel_id channel;
-
-	if (!fromwire_gossip_mark_channel_unroutable(msg, &channel))
-		master_badmsg(WIRE_GOSSIP_MARK_CHANNEL_UNROUTABLE, msg);
-
-	mark_channel_unroutable(daemon->rstate, &channel);
-
-	return daemon_conn_read_next(conn, daemon->master);
-}
-
 /*~ This is where lightningd tells us that a channel's funding transaction has
  * been spent. */
 static struct io_plan *handle_outpoint_spent(struct io_conn *conn,
@@ -2642,9 +2624,6 @@ static struct io_plan *recv_req(struct io_conn *conn,
 	case WIRE_GOSSIP_ROUTING_FAILURE:
 		return handle_routing_failure(conn, daemon, msg);
 
-	case WIRE_GOSSIP_MARK_CHANNEL_UNROUTABLE:
-		return handle_mark_channel_unroutable(conn, daemon, msg);
-
 	case WIRE_GOSSIP_OUTPOINT_SPENT:
 		return handle_outpoint_spent(conn, daemon, msg);
 

gossipd/routing.c

@@ -265,7 +265,6 @@ static void init_half_chan(struct routing_state *rstate,
 	struct half_chan *c = &chan->half[channel_idx];
 
 	c->channel_update = NULL;
-	c->unroutable_until = 0;
 
 	/* Set the channel direction */
 	c->channel_flags = channel_idx;
@@ -438,11 +437,10 @@ static void bfg_one_edge(struct node *node,
 }
 
 /* Determine if the given half_chan is routable */
-static bool hc_is_routable(const struct chan *chan, int idx, time_t now)
+static bool hc_is_routable(const struct chan *chan, int idx)
 {
 	return !chan->local_disabled
-		&& is_halfchan_enabled(&chan->half[idx])
+		&& is_halfchan_enabled(&chan->half[idx]);
-		&& chan->half[idx].unroutable_until < now;
 }
 
 /* riskfactor is already scaled to per-block amount */
@@ -458,10 +456,6 @@ find_route(const tal_t *ctx, struct routing_state *rstate,
 	struct node *n, *src, *dst;
 	struct node_map_iter it;
 	int runs, i, best;
-	/* Call time_now() once at the start, so that our tight loop
-	 * does not keep calling into operating system for the
-	 * current time */
-	time_t now = time_now().ts.tv_sec;
 
 	/* Note: we map backwards, since we know the amount of satoshi we want
 	 * at the end, and need to derive how much we need to send. */
@@ -518,7 +512,7 @@ find_route(const tal_t *ctx, struct routing_state *rstate,
 							    &n->id),
 					     i, num_edges);
 
-				if (!hc_is_routable(chan, idx, now)) {
+				if (!hc_is_routable(chan, idx)) {
 					SUPERVERBOSE("...unroutable (local_disabled = %i, is_halfchan_enabled = %i, unroutable_until = %i",
 						     chan->local_disabled,
 						     is_halfchan_enabled(&chan->half[idx]),
@@ -1040,9 +1034,6 @@ static void set_connection_values(struct chan *chan,
 	c->last_timestamp = timestamp;
 	assert((c->channel_flags & ROUTING_FLAGS_DIRECTION) == idx);
 
-	/* If it was temporarily unroutable, re-enable */
-	c->unroutable_until = 0;
-
 	SUPERVERBOSE("Channel %s/%d was updated.",
 		     type_to_string(tmpctx, struct short_channel_id, &chan->scid),
 		     idx);
@@ -1583,17 +1574,12 @@ static void routing_failure_channel_out(const tal_t *disposal_context,
 					struct chan *chan,
 					time_t now)
 {
-	struct half_chan *hc = half_chan_from(node, chan);
-
 	/* BOLT #4:
 	 *
 	 * - if the PERM bit is NOT set:
 	 *   - SHOULD restore the channels as it receives new `channel_update`s.
 	 */
-	if (!(failcode & PERM))
+	if (failcode & PERM)
-		/* Prevent it for 20 seconds. */
-		hc->unroutable_until = now + 20;
-	else
 		/* Set it up to be pruned. */
 		tal_steal(disposal_context, chan);
 }
@@ -1692,27 +1678,6 @@ void routing_failure(struct routing_state *rstate,
 	}
 }
 
-void mark_channel_unroutable(struct routing_state *rstate,
-			     const struct short_channel_id *channel)
-{
-	struct chan *chan;
-	time_t now = time_now().ts.tv_sec;
-	const char *scid = type_to_string(tmpctx, struct short_channel_id,
-					  channel);
-
-	status_trace("Received mark_channel_unroutable channel %s",
-		     scid);
-
-	chan = get_channel(rstate, channel);
-	if (!chan) {
-		status_unusual("mark_channel_unroutable: "
-			       "channel %s not in routemap",
-			       scid);
-		return;
-	}
-	chan->half[0].unroutable_until = now + 20;
-	chan->half[1].unroutable_until = now + 20;
-}
 
 void route_prune(struct routing_state *rstate)
 {

gossipd/routing.h

@@ -39,10 +39,6 @@ struct half_chan {
 	/* Flags as specified by the `channel_update`s, indicates
 	 * optional fields.  */
 	u8 message_flags;
-
-	/* If greater than current time, this connection should not
-	 * be used for routing. */
-	time_t unroutable_until;
 };
 
 struct chan {
@@ -277,9 +273,6 @@ void routing_failure(struct routing_state *rstate,
 		     const struct short_channel_id *erring_channel,
 		     enum onion_type failcode,
 		     const u8 *channel_update);
-/* Disable specific channel from routing. */
-void mark_channel_unroutable(struct routing_state *rstate,
-			     const struct short_channel_id *channel);
 
 void route_prune(struct routing_state *rstate);
 

lightningd/gossip_control.c

@@ -112,7 +112,6 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 	case WIRE_GOSSIP_GET_TXOUT_REPLY:
 	case WIRE_GOSSIP_OUTPOINT_SPENT:
 	case WIRE_GOSSIP_ROUTING_FAILURE:
-	case WIRE_GOSSIP_MARK_CHANNEL_UNROUTABLE:
 	case WIRE_GOSSIP_QUERY_SCIDS:
 	case WIRE_GOSSIP_QUERY_CHANNEL_RANGE:
 	case WIRE_GOSSIP_SEND_TIMESTAMP_FILTER:

lightningd/pay.c

@@ -394,31 +394,6 @@ remote_routing_failure(const tal_t *ctx,
 	return routing_failure;
 }
 
-static void random_mark_channel_unroutable(struct log *log,
-					   struct subd *gossip,
-					   struct short_channel_id *route_channels)
-{
-	size_t num_channels = tal_count(route_channels);
-	size_t i;
-	const struct short_channel_id *channel;
-	u8 *msg;
-	assert(num_channels != 0);
-
-	/* Select one channel by random. */
-	randombytes_buf(&i, sizeof(i));
-	i = i % num_channels;
-	channel = &route_channels[i];
-
-	log_debug(log,
-		  "Disable randomly %dth channel (%s) along route "
-		  "(guessing due to bad reply)",
-		  (int) i,
-		  type_to_string(tmpctx, struct short_channel_id,
-				 channel));
-	msg = towire_gossip_mark_channel_unroutable(tmpctx, channel);
-	subd_send_msg(gossip, msg);
-}
-
 static void report_routing_failure(struct log *log,
 				   struct subd *gossip,
 				   struct routing_failure *fail)
@@ -535,10 +510,6 @@ void payment_failed(struct lightningd *ld, const struct htlc_out *hout,
 				 tal_hex(tmpctx, hout->failuremsg));
 			/* Cannot report failure. */
 			fail = NULL;
-			/* Select a channel to mark unroutable by random */
-			random_mark_channel_unroutable(hout->key.channel->log,
-						       ld->gossip,
-						       payment->route_channels);
 			/* Can now retry; we selected a channel to mark
 			 * unroutable by random */
 			retry_plausible = true;