Askrene: an EXPERIMENTAL MCF plugin and infrastructure

bitcoin/short_channel_id.h

@@ -41,6 +41,12 @@ struct short_channel_id_dir {
 	int dir;
 };
 
+static inline bool short_channel_id_dir_eq(const struct short_channel_id_dir *a,
+					   const struct short_channel_id_dir *b)
+{
+	return short_channel_id_eq(a->scid, b->scid) && a->dir == b->dir;
+}
+
 static inline u32 short_channel_id_blocknum(struct short_channel_id scid)
 {
 	return scid.u64 >> 40;

common/amount.h

@@ -144,6 +144,19 @@ bool amount_msat_eq_sat(struct amount_msat msat, struct amount_sat sat);
 /* a / b */
 double amount_msat_ratio(struct amount_msat a, struct amount_msat b);
 
+/* min(a,b) and max(a,b) */
+static inline struct amount_msat amount_msat_min(struct amount_msat a,
+						 struct amount_msat b)
+{
+	return amount_msat_less(a, b) ? a : b;
+}
+
+static inline struct amount_msat amount_msat_max(struct amount_msat a,
+						 struct amount_msat b)
+{
+	return amount_msat_greater(a, b) ? a : b;
+}
+
 /* Check whether this asset is actually the main / fee-paying asset of the
  * current chain. */
 bool amount_asset_is_main(struct amount_asset *asset);

common/gossmap.c

@@ -444,7 +444,8 @@ void gossmap_remove_node(struct gossmap *map, struct gossmap_node *node)
  *     * [`point`:`node_id_2`]
  */
 static struct gossmap_chan *add_channel(struct gossmap *map,
-					size_t cannounce_off)
+					size_t cannounce_off,
+					size_t msglen)
 {
 	/* Note that first two bytes are message type */
 	const size_t feature_len_off = 2 + (64 + 64 + 64 + 64);
@@ -473,6 +474,12 @@ static struct gossmap_chan *add_channel(struct gossmap *map,
 		return NULL;
 	}
 
+	/* gossipd writes WIRE_GOSSIP_STORE_CHANNEL_AMOUNT after this (not for
+	 * local channels), so ignore channel_announcement until that appears */
+	if (msglen
+	    && (map->map_size < cannounce_off + msglen + sizeof(struct gossip_hdr) + sizeof(u16) + sizeof(u64)))
+		return NULL;
+
 	/* We carefully map pointers to indexes, since new_node can move them! */
 	n[0] = gossmap_find_node(map, &node_id[0]);
 	if (n[0])
@@ -668,9 +675,11 @@ static bool map_catchup(struct gossmap *map, bool *changed)
 
 		off = map->map_end + sizeof(ghdr);
 		type = map_be16(map, off);
-		if (type == WIRE_CHANNEL_ANNOUNCEMENT)
-			add_channel(map, off);
-		else if (type == WIRE_CHANNEL_UPDATE)
+		if (type == WIRE_CHANNEL_ANNOUNCEMENT) {
+			/* Don't read yet if amount field is not there! */
+			if (!add_channel(map, off, be16_to_cpu(ghdr.len)))
+				break;
+		} else if (type == WIRE_CHANNEL_UPDATE)
 			update_channel(map, off);
 		else if (type == WIRE_GOSSIP_STORE_DELETE_CHAN)
 			remove_channel_by_deletemsg(map, off);
@@ -944,7 +953,7 @@ void gossmap_apply_localmods(struct gossmap *map,
 				continue;
 
 			/* Create new channel, pointing into local. */
-			chan = add_channel(map, map->map_size + mod->local_off);
+			chan = add_channel(map, map->map_size + mod->local_off, 0);
 		}
 
 		/* Save old, overwrite (keep nodeidx) */
@@ -1144,7 +1153,7 @@ bool gossmap_chan_get_capacity(const struct gossmap *map,
 	off += sizeof(ghdr) + be16_to_cpu(ghdr.len);
 
 	/* Partial write, this can happen. */
-	if (off + sizeof(ghdr) + 2 > map->map_size)
+	if (off + sizeof(ghdr) + sizeof(u16) + sizeof(u64) > map->map_size)
 		return false;
 
 	/* Get type of next field. */

common/gossmap.h

@@ -161,7 +161,7 @@ static inline bool gossmap_chan_set(const struct gossmap_chan *chan, int dir)
 	return chan->cupdate_off[dir] != 0;
 }
 
-/* Return capacity if it's known (fails only on race condition, or a local mod) */
+/* Return capacity if it's known (fails on a local mod) */
 bool gossmap_chan_get_capacity(const struct gossmap *map,
 			       const struct gossmap_chan *c,
 			       struct amount_sat *amount);
@@ -242,6 +242,19 @@ bool gossmap_chan_has_capacity(const struct gossmap_chan *chan,
 			       int direction,
 			       struct amount_msat amount);
 
+/* Convenience routines to get htlc min/max as amount_msat */
+static inline struct amount_msat
+gossmap_chan_htlc_max(const struct gossmap_chan *chan, const int dir)
+{
+	return amount_msat(fp16_to_u64(chan->half[dir].htlc_max));
+}
+
+static inline struct amount_msat
+gossmap_chan_htlc_min(const struct gossmap_chan *chan, const int dir)
+{
+	return amount_msat(fp16_to_u64(chan->half[dir].htlc_min));
+}
+
 /* Remove a channel from the map (warning! realloc can move gossmap_chan
  * and gossmap_node ptrs!) */
 void gossmap_remove_chan(struct gossmap *map, struct gossmap_chan *chan);

common/json_param.c

@@ -520,6 +520,18 @@ struct command_result *param_sha256(struct command *cmd, const char *name,
 				     "should be a 32 byte hex value");
 }
 
+struct command_result *param_u16(struct command *cmd, const char *name,
+				 const char *buffer, const jsmntok_t *tok,
+				 uint16_t **num)
+{
+	*num = tal(cmd, uint16_t);
+	if (json_to_u16(buffer, tok, *num))
+		return NULL;
+
+	return command_fail_badparam(cmd, name, buffer, tok,
+				     "should be an unsigned 16 bit integer");
+}
+
 struct command_result *param_u32(struct command *cmd, const char *name,
 				 const char *buffer, const jsmntok_t *tok,
 				 uint32_t **num)

common/json_param.h

@@ -219,6 +219,11 @@ struct command_result *param_sha256(struct command *cmd, const char *name,
 				    const char *buffer, const jsmntok_t *tok,
 				    struct sha256 **hash);
 
+/* Extract number from this (may be a string, or a number literal) */
+struct command_result *param_u16(struct command *cmd, const char *name,
+				 const char *buffer, const jsmntok_t *tok,
+				 uint16_t **num);
+
 /* Extract number from this (may be a string, or a number literal) */
 struct command_result *param_u32(struct command *cmd, const char *name,
 				 const char *buffer, const jsmntok_t *tok,