pay: always send onion error message to gossipd.

There were no channel updates in my log; because sendonion doesn't know the
actual node_ids or channel_ids, we can't tell gossipd what node/channel it was
so it can no longer remove them on PERM errors.

However, we can tell it the error message so it can apply the update.

Fixes: #3877
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

gossipd/gossip_wire.csv

@@ -98,9 +98,6 @@ msgdata,gossip_get_txout_reply,outscript,u8,len
 
 # master->gossipd an htlc failed with this onion error.
 msgtype,gossip_payment_failure,3021
-msgdata,gossip_payment_failure,erring_node,node_id,
-msgdata,gossip_payment_failure,erring_channel,short_channel_id,
-msgdata,gossip_payment_failure,erring_channel_direction,u8,
 msgdata,gossip_payment_failure,len,u16,
 msgdata,gossip_payment_failure,error,u8,len
 

gossipd/gossipd.c

@@ -1506,32 +1506,26 @@ static struct io_plan *handle_payment_failure(struct io_conn *conn,
 					      struct daemon *daemon,
 					      const u8 *msg)
 {
-	struct node_id erring_node;
-	struct short_channel_id erring_channel;
-	u8 erring_channel_direction;
 	u8 *error;
-	enum onion_type failcode;
 	u8 *channel_update;
 
-	if (!fromwire_gossip_payment_failure(msg, msg,
+	if (!fromwire_gossip_payment_failure(msg, msg, &error))
-					     &erring_node,
-					     &erring_channel,
-					     &erring_channel_direction,
-					     &error))
 		master_badmsg(WIRE_GOSSIP_PAYMENT_FAILURE, msg);
 
-	failcode = fromwire_peektype(error);
 	channel_update = channel_update_from_onion_error(tmpctx, error);
-	if (channel_update)
+	if (channel_update) {
 		status_debug("Extracted channel_update %s from onionreply %s",
 			     tal_hex(tmpctx, channel_update),
 			     tal_hex(tmpctx, error));
-	routing_failure(daemon->rstate,
+		u8 *err = handle_channel_update(daemon->rstate, channel_update,
-			&erring_node,
+						NULL, NULL);
-			&erring_channel,
+		if (err) {
-			erring_channel_direction,
+			status_info("extracted bad channel_update %s from onionreply %s",
-			failcode,
+				    sanitize_error(err, err, NULL),
-			channel_update);
+				    error);
+			tal_free(err);
+		}
+	}
 
 	return daemon_conn_read_next(conn, daemon->master);
 }

gossipd/routing.c

@@ -2762,96 +2762,6 @@ struct route_hop **get_route(const tal_t *ctx, struct routing_state *rstate,
 	return hops;
 }
 
-void routing_failure(struct routing_state *rstate,
-		     const struct node_id *erring_node_id,
-		     const struct short_channel_id *scid,
-		     int erring_direction,
-		     enum onion_type failcode,
-		     const u8 *channel_update)
-{
-	struct chan **pruned = tal_arr(tmpctx, struct chan *, 0);
-
-	status_debug("Received routing failure 0x%04x (%s), "
-		     "erring node %s, "
-		     "channel %s/%u",
-		     (int) failcode, onion_type_name(failcode),
-		     type_to_string(tmpctx, struct node_id, erring_node_id),
-		     type_to_string(tmpctx, struct short_channel_id, scid),
-		     erring_direction);
-
-	/* lightningd will only extract this if UPDATE is set. */
-	if (channel_update) {
-		u8 *err = handle_channel_update(rstate, channel_update,
-						NULL, NULL);
-		if (err) {
-			status_unusual("routing_failure: "
-				       "bad channel_update %s",
-				       sanitize_error(err, err, NULL));
-			tal_free(err);
-		}
-	} else if (failcode & UPDATE) {
-		status_unusual("routing_failure: "
-			       "UPDATE bit set, no channel_update. "
-			       "failcode: 0x%04x",
-			       (int) failcode);
-	}
-
-	/* We respond to permanent errors, ignore the rest: they're
-	 * for the pay command to worry about.  */
-	if (!(failcode & PERM))
-		return;
-
-	if (failcode & NODE) {
-		struct node *node = get_node(rstate, erring_node_id);
-		if (!node) {
-			status_unusual("routing_failure: Erring node %s not in map",
-				       type_to_string(tmpctx, struct node_id,
-						      erring_node_id));
-		} else {
-			struct chan_map_iter i;
-			struct chan *c;
-
-			status_debug("Deleting node %s",
-				     type_to_string(tmpctx,
-						    struct node_id,
-						    &node->id));
-			for (c = first_chan(node, &i); c; c = next_chan(node, &i)) {
-				/* Set it up to be pruned. */
-				tal_arr_expand(&pruned, c);
-			}
-		}
-	} else {
-		struct chan *chan = get_channel(rstate, scid);
-
-		if (!chan)
-			status_unusual("routing_failure: "
-				       "Channel %s unknown",
-				       type_to_string(tmpctx,
-						      struct short_channel_id,
-						      scid));
-		else {
-			/* This error can be triggered by sendpay if caller
-			 * uses the wrong key for dest. */
-			if (failcode == WIRE_INVALID_ONION_HMAC
-			    && !node_id_eq(&chan->nodes[!erring_direction]->id,
-					   erring_node_id))
-				return;
-
-			status_debug("Deleting channel %s",
-				     type_to_string(tmpctx,
-						    struct short_channel_id,
-						    scid));
-			/* Set it up to be deleted. */
-			tal_arr_expand(&pruned, chan);
-		}
-	}
-
-	/* Now free all the chans and maybe even nodes. */
-	for (size_t i = 0; i < tal_count(pruned); i++)
-		free_chan(rstate, pruned[i]);
-}
-
-
 void route_prune(struct routing_state *rstate)
 {
 	u64 now = gossip_time_now(rstate).ts.tv_sec;

gossipd/routing.h

@@ -424,13 +424,6 @@ struct route_hop **get_route(const tal_t *ctx, struct routing_state *rstate,
 			     u64 seed,
 			     struct exclude_entry **excluded,
 			     u32 max_hops);
-/* Disable channel(s) based on the given routing failure. */
-void routing_failure(struct routing_state *rstate,
-		     const struct node_id *erring_node,
-		     const struct short_channel_id *erring_channel,
-		     int erring_direction,
-		     enum onion_type failcode,
-		     const u8 *channel_update);
 
 void route_prune(struct routing_state *rstate);
 

lightningd/pay.c

@@ -437,8 +437,6 @@ remote_routing_failure(const tal_t *ctx,
 			*pay_errcode = PAY_TRY_OTHER_ROUTE;
 		erring_node = &route_nodes[origin_index];
 	} else {
-		u8 *gossip_msg;
-
 		*pay_errcode = PAY_TRY_OTHER_ROUTE;
 
 		/* Report the *next* channel as failing. */
@@ -455,18 +453,14 @@ remote_routing_failure(const tal_t *ctx,
 			erring_node = &route_nodes[origin_index + 1];
 		} else
 			erring_node = &route_nodes[origin_index];
-
-		/* Tell gossipd: it may want to remove channels or even nodes
-		 * in response to this, and there may be a channel_update
-		 * embedded too */
-		gossip_msg = towire_gossip_payment_failure(NULL,
-							   erring_node,
-							   erring_channel,
-							   dir,
-							   failuremsg);
-		subd_send_msg(ld->gossip, take(gossip_msg));
 	}
 
+	/* Tell gossipd; it will try to extract channel_update */
+	/* FIXME: sendonion caller should do this, and inform gossipd of any
+	 * permanent errors. */
+	subd_send_msg(ld->gossip,
+		      take(towire_gossip_payment_failure(NULL, failuremsg)));
+
 	routing_failure->erring_index = (unsigned int) (origin_index + 1);
 	routing_failure->failcode = failcode;
 	routing_failure->msg = tal_dup_talarr(routing_failure, u8, failuremsg);