renepay: uncertainty network update revisited

- Update the uncertainty network with the gossmap+local_gossmods,
- ignore channels that fail to give their capacity.

plugins/renepay/main.c

@@ -76,7 +76,13 @@ static const char *init(struct plugin *p,
 			   "gossmap ignored %zu channel updates",
 			   num_channel_updates_rejected);
 	pay_plugin->uncertainty = uncertainty_new(pay_plugin);
-	uncertainty_update(pay_plugin->uncertainty, pay_plugin->gossmap);
+	int skipped_count =
+	    uncertainty_update(pay_plugin->uncertainty, pay_plugin->gossmap);
+	if (skipped_count)
+		plugin_log(pay_plugin->plugin, LOG_UNUSUAL,
+			   "%s: uncertainty was updated but %d channels have "
+			   "been ignored.",
+			   __PRETTY_FUNCTION__, skipped_count);
 
 	plugin_set_memleak_handler(p, memleak_mark);
 	return NULL;

plugins/renepay/mods.c

@@ -519,6 +519,8 @@ refreshgossmap_done(struct command *cmd UNUSED, const char *buf UNUSED,
 		    const jsmntok_t *result UNUSED, struct payment *payment)
 {
 	assert(pay_plugin->gossmap); // gossmap must be already initialized
+	assert(payment);
+	assert(payment->local_gossmods);
 
 	size_t num_channel_updates_rejected;
 	bool gossmap_changed =
@@ -529,8 +531,20 @@ refreshgossmap_done(struct command *cmd UNUSED, const char *buf UNUSED,
 			   "gossmap ignored %zu channel updates",
 			   num_channel_updates_rejected);
 
-	if (gossmap_changed)
-		uncertainty_update(pay_plugin->uncertainty, pay_plugin->gossmap);
+	if (gossmap_changed) {
+		gossmap_apply_localmods(pay_plugin->gossmap,
+					payment->local_gossmods);
+		int skipped_count = uncertainty_update(pay_plugin->uncertainty,
+						       pay_plugin->gossmap);
+		gossmap_remove_localmods(pay_plugin->gossmap,
+					 payment->local_gossmods);
+		if (skipped_count)
+			plugin_log(
+			    pay_plugin->plugin, LOG_UNUSUAL,
+			    "%s: uncertainty was updated but %d channels have "
+			    "been ignored.",
+			    __PRETTY_FUNCTION__, skipped_count);
+	}
 	return payment_continue(payment);
 }
 
@@ -560,6 +574,9 @@ static void add_hintchan(struct payment *payment, const struct node_id *src,
 			 const struct short_channel_id scid, u32 fee_base_msat,
 			 u32 fee_proportional_millionths)
 {
+	assert(payment);
+	assert(payment->local_gossmods);
+
 	// TODO test this, simply make a payment through a private channel, this
 	// statement is either right or wrong.
 	int dir = node_id_cmp(src, dst) < 0 ? 0 : 1;
@@ -623,8 +640,11 @@ static struct command_result *routehints_done(struct command *cmd UNUSED,
 					      struct payment *payment)
 {
 	// FIXME are there route hints for B12?
+	assert(payment);
+	assert(payment->local_gossmods);
 	assert(payment->routehints);
 	const size_t nhints = tal_count(payment->routehints);
+	/* Hints are added to the local_gossmods. */
 	for (size_t i = 0; i < nhints; i++) {
 		/* Each one, presumably, leads to the destination */
 		const struct route_info *r = payment->routehints[i];
@@ -638,6 +658,18 @@ static struct command_result *routehints_done(struct command *cmd UNUSED,
 			end = &r[j].pubkey;
 		}
 	}
+
+	/* Add hints to the uncertainty network. */
+	gossmap_apply_localmods(pay_plugin->gossmap, payment->local_gossmods);
+	int skipped_count =
+	    uncertainty_update(pay_plugin->uncertainty, pay_plugin->gossmap);
+	gossmap_remove_localmods(pay_plugin->gossmap, payment->local_gossmods);
+	if (skipped_count)
+		plugin_log(pay_plugin->plugin, LOG_UNUSUAL,
+			   "%s: uncertainty was updated but %d channels have "
+			   "been ignored.",
+			   __PRETTY_FUNCTION__, skipped_count);
+
 	return payment_continue(payment);
 }
 

plugins/renepay/test/run-mcf.c

@@ -361,7 +361,8 @@ int main(int argc, char *argv[])
 	assert(short_channel_id_from_str("103x1x0", 7, &scid23));
 
 	struct uncertainty *uncertainty = uncertainty_new(tmpctx);
-	uncertainty_update(uncertainty, gossmap);
+	int skipped_count = uncertainty_update(uncertainty, gossmap);
+	assert(skipped_count == 0);
 
 	printf("All set, now let's call minflow ...\n");
 

plugins/renepay/uncertainty.c

@@ -78,33 +78,56 @@ void uncertainty_channel_cannot_send(struct uncertainty *uncertainty,
 	chan_extra_cannot_send(uncertainty->chan_extra_map, &scidd);
 }
 
-void uncertainty_update(struct uncertainty *uncertainty,
-			struct gossmap *gossmap)
+int uncertainty_update(struct uncertainty *uncertainty, struct gossmap *gossmap)
 {
-	// FIXME: after running for some time we might find some channels in
-	// chan_extra_map that are not needed and do not exist in the gossmap
-	// for being private or closed.
+	/* Each channel in chan_extra_map should be either in gossmap or in
+	 * local_gossmods. */
+	assert(uncertainty);
+	struct chan_extra_map *chan_extra_map = uncertainty->chan_extra_map;
+	assert(chan_extra_map);
+	struct chan_extra **del_list = tal_arr(NULL, struct chan_extra*, 0);
+	struct chan_extra_map_iter it;
+	for (struct chan_extra *ch = chan_extra_map_first(chan_extra_map, &it);
+	     ch; ch = chan_extra_map_next(chan_extra_map, &it)) {
+
+		/* If we cannot find that channel in the gossmap, add it to the
+		 * delete list. */
+		if (!gossmap_find_chan(gossmap, &ch->scid))
+			tal_arr_expand(&del_list, ch);
+	}
+	for(size_t i=0;i<tal_count(del_list);i++) {
+		chan_extra_map_del(chan_extra_map, del_list[i]);
+	}
+	del_list = tal_free(del_list);
+
 
 	/* For each channel in the gossmap, create a extra data in
 	 * chan_extra_map */
+	int skipped_count = 0;
 	for (struct gossmap_chan *chan = gossmap_first_chan(gossmap); chan;
 	     chan = gossmap_next_chan(gossmap, chan)) {
 		struct short_channel_id scid = gossmap_chan_scid(gossmap, chan);
 		struct chan_extra *ce =
-		    chan_extra_map_get(uncertainty->chan_extra_map,
+		    chan_extra_map_get(chan_extra_map,
 				       gossmap_chan_scid(gossmap, chan));
 		if (!ce) {
 			struct amount_sat cap;
 			struct amount_msat cap_msat;
 
-			// FIXME: check errors
 			if (!gossmap_chan_get_capacity(gossmap, chan, &cap) ||
 			    !amount_sat_to_msat(&cap_msat, cap) ||
-			    !new_chan_extra(uncertainty->chan_extra_map, scid,
-					    cap_msat))
-				return;
+			    !new_chan_extra(chan_extra_map, scid,
+					    cap_msat)) {
+				/* If the new chan_extra cannot be created we
+				 * skip this channel. */
+				skipped_count++;
+				continue;
+			}
 		}
 	}
+	assert(chan_extra_map_count(chan_extra_map) + skipped_count ==
+	       gossmap_num_chans(gossmap));
+	return skipped_count;
 }
 
 struct uncertainty *uncertainty_new(const tal_t *ctx)

plugins/renepay/uncertainty.h

@@ -35,8 +35,8 @@ void uncertainty_channel_cannot_send(struct uncertainty *uncertainty,
 				     struct short_channel_id scid,
 				     int direction);
 
-void uncertainty_update(struct uncertainty *uncertainty,
-			struct gossmap *gossmap);
+WARN_UNUSED_RESULT int uncertainty_update(struct uncertainty *uncertainty,
+					  struct gossmap *gossmap);
 
 struct uncertainty *uncertainty_new(const tal_t *ctx);