From 0073e492d915630b2521fbebc7f3cac0db9a80e6 Mon Sep 17 00:00:00 2001 From: Wilmer Paulino Date: Tue, 23 Jan 2024 16:55:40 -0800 Subject: [PATCH] Refactor HTLCFailureMsg generation out from decode_update_add_htlc_onion In the future, we plan to complete remove `decode_update_add_htlc_onion` and replace it with a batched variant. This refactor, while improving readability in its current form, does not feature any functional changes and allows us to reuse most of the logic in the batched variant. --- lightning/src/ln/channelmanager.rs | 113 +++++++++++++++-------------- 1 file changed, 59 insertions(+), 54 deletions(-) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 685caba75..85a9a4041 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -3094,6 +3094,61 @@ where } } + fn htlc_failure_from_update_add_err( + &self, msg: &msgs::UpdateAddHTLC, counterparty_node_id: &PublicKey, err_msg: &'static str, + mut err_code: u16, chan_update: Option, is_intro_node_blinded_forward: bool, + shared_secret: &[u8; 32] + ) -> HTLCFailureMsg { + let mut res = VecWriter(Vec::with_capacity(chan_update.serialized_length() + 2 + 8 + 2)); + if let Some(chan_update) = chan_update { + if err_code == 0x1000 | 11 || err_code == 0x1000 | 12 { + msg.amount_msat.write(&mut res).expect("Writes cannot fail"); + } + else if err_code == 0x1000 | 13 { + msg.cltv_expiry.write(&mut res).expect("Writes cannot fail"); + } + else if err_code == 0x1000 | 20 { + // TODO: underspecified, follow https://github.com/lightning/bolts/issues/791 + 0u16.write(&mut res).expect("Writes cannot fail"); + } + (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 err_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. + err_code = 0x2000 | 2; + } + + log_info!( + WithContext::from(&self.logger, Some(*counterparty_node_id), Some(msg.channel_id)), + "Failed to accept/forward incoming HTLC: {}", err_msg + ); + // If `msg.blinding_point` is set, we must always fail with malformed. + if msg.blinding_point.is_some() { + return HTLCFailureMsg::Malformed(msgs::UpdateFailMalformedHTLC { + channel_id: msg.channel_id, + htlc_id: msg.htlc_id, + sha256_of_onion: [0; 32], + failure_code: INVALID_ONION_BLINDING, + }); + } + + let (err_code, err_data) = if is_intro_node_blinded_forward { + (INVALID_ONION_BLINDING, &[0; 32][..]) + } else { + (err_code, &res.0[..]) + }; + HTLCFailureMsg::Relay(msgs::UpdateFailHTLC { + channel_id: msg.channel_id, + htlc_id: msg.htlc_id, + reason: HTLCFailReason::reason(err_code, err_data.to_vec()) + .get_encrypted_failure_packet(shared_secret, &None), + }) + } + fn decode_update_add_htlc_onion( &self, msg: &msgs::UpdateAddHTLC, counterparty_node_id: &PublicKey, ) -> Result< @@ -3103,36 +3158,6 @@ where msg, &self.node_signer, &self.logger, &self.secp_ctx )?; - macro_rules! return_err { - ($msg: expr, $err_code: expr, $data: expr) => { - { - log_info!( - WithContext::from(&self.logger, Some(*counterparty_node_id), Some(msg.channel_id)), - "Failed to accept/forward incoming HTLC: {}", $msg - ); - // If `msg.blinding_point` is set, we must always fail with malformed. - if msg.blinding_point.is_some() { - return Err(HTLCFailureMsg::Malformed(msgs::UpdateFailMalformedHTLC { - channel_id: msg.channel_id, - htlc_id: msg.htlc_id, - sha256_of_onion: [0; 32], - failure_code: INVALID_ONION_BLINDING, - })); - } - - let (err_code, err_data) = if next_hop.is_intro_node_blinded_forward() { - (INVALID_ONION_BLINDING, &[0; 32][..]) - } else { ($err_code, $data) }; - return Err(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC { - channel_id: msg.channel_id, - htlc_id: msg.htlc_id, - reason: HTLCFailReason::reason(err_code, err_data.to_vec()) - .get_encrypted_failure_packet(&shared_secret, &None), - })); - } - } - } - let NextPacketDetails { next_packet_pubkey, outgoing_amt_msat, outgoing_scid, outgoing_cltv_value } = match next_packet_details_opt { @@ -3143,7 +3168,7 @@ where // Perform outbound checks here instead of in [`Self::construct_pending_htlc_info`] because we // can't hold the outbound peer state lock at the same time as the inbound peer state lock. - if let Some((err, mut code, chan_update)) = loop { + if let Some((err, code, chan_update)) = loop { let id_option = self.short_to_chan_info.read().unwrap().get(&outgoing_scid).cloned(); let forwarding_chan_info_opt = match id_option { None => { // unknown_next_peer @@ -3236,29 +3261,9 @@ where break None; } { - let mut res = VecWriter(Vec::with_capacity(chan_update.serialized_length() + 2 + 8 + 2)); - if let Some(chan_update) = chan_update { - if code == 0x1000 | 11 || code == 0x1000 | 12 { - msg.amount_msat.write(&mut res).expect("Writes cannot fail"); - } - else if code == 0x1000 | 13 { - msg.cltv_expiry.write(&mut res).expect("Writes cannot fail"); - } - else if code == 0x1000 | 20 { - // TODO: underspecified, follow https://github.com/lightning/bolts/issues/791 - 0u16.write(&mut res).expect("Writes cannot fail"); - } - (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[..]); + return Err(self.htlc_failure_from_update_add_err( + msg, counterparty_node_id, err, code, chan_update, next_hop.is_intro_node_blinded_forward(), &shared_secret + )); } Ok((next_hop, shared_secret, Some(next_packet_pubkey))) } -- 2.39.5