From f85425d1066ff3450cf63916e8240cd90b6c301f Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Wed, 23 Mar 2022 09:29:20 +1030
Subject: [PATCH] lightningd: don't assume a single channel per peer.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 lightningd/routehint.c                      | 20 ++++++++++++++++----
 lightningd/test/run-invoice-select-inchan.c |  7 ++++---
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/lightningd/routehint.c b/lightningd/routehint.c
index a9879e3a3..29a1439bc 100644
--- a/lightningd/routehint.c
+++ b/lightningd/routehint.c
@@ -99,14 +99,25 @@ routehint_candidates(const tal_t *ctx,
 		if (!peer) {
 			log_debug(ld->log, "%s: unknown peer",
 				  type_to_string(tmpctx,
-						 struct short_channel_id,
-						 &r->short_channel_id));
+						 struct node_id,
+						 &r->pubkey));
 			continue;
 		}
 
-		/* Does it have a channel in state CHANNELD_NORMAL */
-		candidate.c = peer_normal_channel(peer);
+		/* Check channel is in CHANNELD_NORMAL */
+		candidate.c = find_channel_by_scid(peer, &r->short_channel_id);
 		if (!candidate.c) {
+			log_debug(ld->log, "%s: channel not found in peer %s",
+				  type_to_string(tmpctx,
+						 struct short_channel_id,
+						 &r->short_channel_id),
+				  type_to_string(tmpctx,
+						 struct node_id,
+						 &r->pubkey));
+			continue;
+		}
+
+		if (candidate.c->state != CHANNELD_NORMAL) {
 			log_debug(ld->log, "%s: abnormal channel",
 				  type_to_string(tmpctx,
 						 struct short_channel_id,
@@ -120,6 +131,7 @@ routehint_candidates(const tal_t *ctx,
 		 * capacity ceiling.  We *could* do multiple HTLCs,
 		 * but presumably that would defeat the spirit of the
 		 * limit anyway */
+		/* FIXME: Present max capacity of multiple channels? */
 		candidate.capacity = channel_amount_receivable(candidate.c);
 		if (amount_msat_greater(candidate.capacity, htlc_max))
 			candidate.capacity = htlc_max;
diff --git a/lightningd/test/run-invoice-select-inchan.c b/lightningd/test/run-invoice-select-inchan.c
index dec7c3a72..17e3c9d1b 100644
--- a/lightningd/test/run-invoice-select-inchan.c
+++ b/lightningd/test/run-invoice-select-inchan.c
@@ -191,6 +191,10 @@ u8 *featurebits_or(const tal_t *ctx UNNEEDED, const u8 *f1 TAKES UNNEEDED, const
 struct channel *find_channel_by_id(const struct peer *peer UNNEEDED,
 				   const struct channel_id *cid UNNEEDED)
 { fprintf(stderr, "find_channel_by_id called!\n"); abort(); }
+/* Generated stub for find_channel_by_scid */
+struct channel *find_channel_by_scid(const struct peer *peer UNNEEDED,
+				     const struct short_channel_id *scid UNNEEDED)
+{ fprintf(stderr, "find_channel_by_scid called!\n"); abort(); }
 /* Generated stub for find_plugin_for_command */
 struct plugin *find_plugin_for_command(struct lightningd *ld UNNEEDED,
 				       const char *cmd_name UNNEEDED)
@@ -585,9 +589,6 @@ struct command_result *param_u64(struct command *cmd UNNEEDED, const char *name
 /* Generated stub for peer_active_channel */
 struct channel *peer_active_channel(struct peer *peer UNNEEDED)
 { fprintf(stderr, "peer_active_channel called!\n"); abort(); }
-/* Generated stub for peer_normal_channel */
-struct channel *peer_normal_channel(struct peer *peer UNNEEDED)
-{ fprintf(stderr, "peer_normal_channel called!\n"); abort(); }
 /* Generated stub for peer_restart_dualopend */
 void peer_restart_dualopend(struct peer *peer UNNEEDED,
 			    struct peer_fd *peer_fd UNNEEDED,