Correctly handle any `UPDATE` errors to phandom invoices

[rust-lightning] / lightning / src / ln / channelmanager.rs

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index e0a54841e5d432d8bce0cc0f16ecdb909eb18ca0..6e5df15908adb097ea5b96655b234e46ac66907a 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -2222,7 +2222,7 @@ impl<M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelManager<M, T, K, F
                        // with a short_channel_id of 0. This is important as various things later assume
                        // short_channel_id is non-0 in any ::Forward.
                        if let &PendingHTLCRouting::Forward { ref short_channel_id, .. } = routing {
-                               if let Some((err, code, chan_update)) = loop {
+                               if let Some((err, mut code, chan_update)) = loop {
                                        let id_option = self.short_to_chan_info.read().unwrap().get(&short_channel_id).cloned();
                                        let mut channel_state = self.channel_state.lock().unwrap();
                                        let forwarding_id_opt = match id_option {
@@ -2331,6 +2331,12 @@ impl<M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelManager<M, T, K, F
                                                (chan_update.serialized_length() as u16 + 2).write(&mut res).expect("Writes cannot fail");
                                                msgs::ChannelUpdate::TYPE.write(&mut res).expect("Writes cannot fail");
                                                chan_update.write(&mut res).expect("Writes cannot fail");
+                                       } else if code & 0x1000 == 0x1000 {
+                                               // If we're trying to return an error that requires a `channel_update` but
+                                               // we're forwarding to a phantom or intercept "channel" (i.e. cannot
+                                               // generate an update), just use the generic "temporary_node_failure"
+                                               // instead.
+                                               code = 0x2000 | 2;
                                        }
                                        return_err!(err, code, &res.0[..]);
                                }