From 4ecf3f46dfd56e26d2bb3952d4c4ca3ef92f9221 Mon Sep 17 00:00:00 2001 From: Valentine Wallace Date: Thu, 26 Oct 2023 19:47:31 -0400 Subject: [PATCH] Set up Channel::fail_htlc to be able to return update_malformed Currently it returns only update_fail, but we'll want it to be able to return update_malformed as well in upcoming commits. We'll use this for correctly failing blinded received HTLCs backwards with malformed and invalid_onion_blinding error per BOLT 4. --- lightning/src/ln/channel.rs | 52 +++++++++++++++++++++++++++---------- 1 file changed, 39 insertions(+), 13 deletions(-) diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index a1af5e6da..44b09a861 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -2523,6 +2523,36 @@ struct CommitmentTxInfoCached { feerate: u32, } +/// Contents of a wire message that fails an HTLC backwards. Useful for [`Channel::fail_htlc`] to +/// fail with either [`msgs::UpdateFailMalformedHTLC`] or [`msgs::UpdateFailHTLC`] as needed. +trait FailHTLCContents { + type Message: FailHTLCMessageName; + fn to_message(self, htlc_id: u64, channel_id: ChannelId) -> Self::Message; + fn to_inbound_htlc_state(self) -> InboundHTLCState; + fn to_htlc_update_awaiting_ack(self, htlc_id: u64) -> HTLCUpdateAwaitingACK; +} +impl FailHTLCContents for msgs::OnionErrorPacket { + type Message = msgs::UpdateFailHTLC; + fn to_message(self, htlc_id: u64, channel_id: ChannelId) -> Self::Message { + msgs::UpdateFailHTLC { htlc_id, channel_id, reason: self } + } + fn to_inbound_htlc_state(self) -> InboundHTLCState { + InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(self)) + } + fn to_htlc_update_awaiting_ack(self, htlc_id: u64) -> HTLCUpdateAwaitingACK { + HTLCUpdateAwaitingACK::FailHTLC { htlc_id, err_packet: self } + } +} + +trait FailHTLCMessageName { + fn name() -> &'static str; +} +impl FailHTLCMessageName for msgs::UpdateFailHTLC { + fn name() -> &'static str { + "update_fail_htlc" + } +} + impl Channel where SP::Target: SignerProvider, ::EcdsaSigner: WriteableEcdsaChannelSigner @@ -2831,8 +2861,10 @@ impl Channel where /// If we do fail twice, we `debug_assert!(false)` and return `Ok(None)`. Thus, this will always /// return `Ok(_)` if preconditions are met. In any case, `Err`s will only be /// [`ChannelError::Ignore`]. - fn fail_htlc(&mut self, htlc_id_arg: u64, err_packet: msgs::OnionErrorPacket, mut force_holding_cell: bool, logger: &L) - -> Result, ChannelError> where L::Target: Logger { + fn fail_htlc( + &mut self, htlc_id_arg: u64, err_packet: E, mut force_holding_cell: bool, + logger: &L + ) -> Result, ChannelError> where L::Target: Logger { if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) { panic!("Was asked to fail an HTLC when channel was not in an operational state"); } @@ -2897,24 +2929,18 @@ impl Channel where } } log_trace!(logger, "Placing failure for HTLC ID {} in holding cell in channel {}.", htlc_id_arg, &self.context.channel_id()); - self.context.holding_cell_htlc_updates.push(HTLCUpdateAwaitingACK::FailHTLC { - htlc_id: htlc_id_arg, - err_packet, - }); + self.context.holding_cell_htlc_updates.push(err_packet.to_htlc_update_awaiting_ack(htlc_id_arg)); return Ok(None); } - log_trace!(logger, "Failing HTLC ID {} back with a update_fail_htlc message in channel {}.", htlc_id_arg, &self.context.channel_id()); + log_trace!(logger, "Failing HTLC ID {} back with {} message in channel {}.", htlc_id_arg, + E::Message::name(), &self.context.channel_id()); { let htlc = &mut self.context.pending_inbound_htlcs[pending_idx]; - htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(err_packet.clone())); + htlc.state = err_packet.clone().to_inbound_htlc_state(); } - Ok(Some(msgs::UpdateFailHTLC { - channel_id: self.context.channel_id(), - htlc_id: htlc_id_arg, - reason: err_packet - })) + Ok(Some(err_packet.to_message(htlc_id_arg, self.context.channel_id()))) } // Message handlers: -- 2.39.5