lightningd: use proper receivable calc for routehint selection.

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

lightningd/invoice.c

@@ -436,39 +436,6 @@ static struct command_result *parse_fallback(struct command *cmd,
 	return NULL;
 }
 
-/** incoming_capacity
- *
- * @brief Determine the ability of the peer to pay us.
- *
- * @param ld - the lightningd.
- * @param c - the channel to check.
- * @param capacity_to_pay_us - out; if this returns true,
- * the pointed-to `struct amount_msat` will contain how
- * much the peer can pay us at maximum.
- *
- * @return false if the peer cannot pay to us, true if
- * the peer can pay us and `capacity_to_pay_us` is set.
- */
-static bool incoming_capacity(struct lightningd *ld,
-			      struct channel *c,
-			      struct amount_msat *capacity_to_pay_us)
-{
-	struct amount_msat their_msat;
-	if (!amount_sat_sub_msat(&their_msat, c->funding, c->our_msat)) {
-		log_broken(ld->log,
-			   "underflow: funding %s - our_msat %s",
-			   type_to_string(tmpctx, struct amount_sat,
-					  &c->funding),
-			   type_to_string(tmpctx, struct amount_msat,
-					  &c->our_msat));
-		return false;
-	}
-	if (!amount_msat_sub_sat(capacity_to_pay_us, their_msat,
-			c->our_config.channel_reserve))
-		return false;
-	return true;
-}
-
 /*
  * From array of incoming channels [inchan], find suitable ones for
  * a payment-to-us of [amount_needed], using criteria:
@@ -530,9 +497,7 @@ static struct route_info **select_inchan(const tal_t *ctx,
 		0       ^             ^                                ^                funding
 		   our_reserve     our_msat	*/
 
-		/* Can the peer pay to us, and if so how much?  */
-		if (!incoming_capacity(ld, c, &capacity_to_pay_us))
-			continue;
+		capacity_to_pay_us = channel_amount_receivable(c);
 
 		/* Does the peer have sufficient balance to pay us,
 		 * even after having taken into account their reserve? */
@@ -628,9 +593,7 @@ static struct route_info **select_inchan_mpp(const tal_t *ctx,
 			continue;
 		}
 
-		/* Can the peer pay to us?  */
-		if (!incoming_capacity(ld, c, &capacity_to_pay_us))
-			continue;
+		capacity_to_pay_us = channel_amount_receivable(c);
 
 		/* Is the channel in the inchans input?  */
 		found = NULL;

lightningd/test/run-invoice-select-inchan.c

@@ -142,6 +142,9 @@ u32 get_feerate(const struct fee_states *fee_states UNNEEDED,
 		enum side opener UNNEEDED,
 		enum side side UNNEEDED)
 { fprintf(stderr, "get_feerate called!\n"); abort(); }
+/* Generated stub for hash_htlc_key */
+size_t hash_htlc_key(const struct htlc_key *htlc_key UNNEEDED)
+{ fprintf(stderr, "hash_htlc_key called!\n"); abort(); }
 /* Generated stub for htlc_is_trimmed */
 bool htlc_is_trimmed(enum side htlc_owner UNNEEDED,
 		     struct amount_msat htlc_amount UNNEEDED,
@@ -679,13 +682,17 @@ static void add_peer(struct lightningd *ld, int n, enum channel_state state,
 	memset(&peer->id, n, sizeof(peer->id));
 	list_head_init(&peer->channels);
 	list_add_tail(&ld->peers, &peer->list);
+	peer->ld = ld;
 
 	c->state = state;
 	c->owner = connected ? (void *)peer : NULL;
+	c->opener = LOCAL;
+	c->peer = peer;
 	/* Channel has incoming capacity n*1000 - 1 millisatoshi */
 	c->funding.satoshis = n+1;
 	c->our_msat = AMOUNT_MSAT(1);
 	c->our_config.channel_reserve = AMOUNT_SAT(1);
+	c->our_config.htlc_minimum = AMOUNT_MSAT(0);
 	c->channel_info.their_config.channel_reserve = AMOUNT_SAT(0);
 	list_add_tail(&peer->channels, &c->list);
 }
@@ -715,6 +722,8 @@ int main(void)
 	ld = tal(tmpctx, struct lightningd);
 
 	list_head_init(&ld->peers);
+	htlc_in_map_init(&ld->htlcs_in);
+	chainparams = chainparams_for_network("regtest");
 
 	inchans = tal_arr(tmpctx, struct route_info, 0);
 	deadends = tal_arrz(tmpctx, bool, 100);