From db2e7e75c451bba0f1d0b75aa62fa6212d008215 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Fri, 17 Sep 2021 17:32:36 +0000 Subject: [PATCH] Support send/recv'ing the new channel_type field in open_channel This implements the channel type negotiation, though as we currently only support channels with only static_remotekey set, it doesn't implement the negotiation explicitly. --- lightning/src/ln/channel.rs | 45 +++++++++++++++++++++++++++++++++++-- 1 file changed, 43 insertions(+), 2 deletions(-) diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index 3e2b05d08..68bcf8998 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -23,7 +23,7 @@ use bitcoin::secp256k1::{Secp256k1,Signature}; use bitcoin::secp256k1; use ln::{PaymentPreimage, PaymentHash}; -use ln::features::{ChannelFeatures, InitFeatures}; +use ln::features::{ChannelFeatures, ChannelTypeFeatures, InitFeatures}; use ln::msgs; use ln::msgs::{DecodeError, OptionalField, DataLossProtect}; use ln::script::{self, ShutdownScript}; @@ -550,6 +550,9 @@ pub(super) struct Channel { // is fine, but as a sanity check in our failure to generate the second claim, we check here // that the original was a claim, and that we aren't now trying to fulfill a failed HTLC. historical_inbound_htlc_fulfills: HashSet, + + /// This channel's type, as negotiated during channel open + channel_type: ChannelTypeFeatures, } #[cfg(any(test, feature = "fuzztarget"))] @@ -775,6 +778,11 @@ impl Channel { #[cfg(any(test, feature = "fuzztarget"))] historical_inbound_htlc_fulfills: HashSet::new(), + + // We currently only actually support one channel type, so don't retry with new types + // on error messages. When we support more we'll need fallback support (assuming we + // want to support old types). + channel_type: ChannelTypeFeatures::only_static_remote_key(), }) } @@ -803,6 +811,23 @@ impl Channel { where K::Target: KeysInterface, F::Target: FeeEstimator { + // First check the channel type is known, failing before we do anything else if we don't + // support this channel type. + let channel_type = if let Some(channel_type) = &msg.channel_type { + if channel_type.supports_any_optional_bits() { + return Err(ChannelError::Close("Channel Type field contained optional bits - this is not allowed".to_owned())); + } + if *channel_type != ChannelTypeFeatures::only_static_remote_key() { + return Err(ChannelError::Close("Channel Type was not understood".to_owned())); + } + channel_type.clone() + } else { + ChannelTypeFeatures::from_counterparty_init(&their_features) + }; + if !channel_type.supports_static_remote_key() { + return Err(ChannelError::Close("Channel Type was not understood - we require static remote key".to_owned())); + } + let holder_signer = keys_provider.get_channel_signer(true, msg.funding_satoshis); let pubkeys = holder_signer.pubkeys().clone(); let counterparty_pubkeys = ChannelPublicKeys { @@ -1043,6 +1068,8 @@ impl Channel { #[cfg(any(test, feature = "fuzztarget"))] historical_inbound_htlc_fulfills: HashSet::new(), + + channel_type, }; Ok(chan) @@ -4283,7 +4310,7 @@ impl Channel { Some(script) => script.clone().into_inner(), None => Builder::new().into_script(), }), - channel_type: None, + channel_type: Some(self.channel_type.clone()), } } @@ -5241,6 +5268,7 @@ impl Writeable for Channel { (7, self.shutdown_scriptpubkey, option), (9, self.target_closing_feerate_sats_per_kw, option), (11, self.monitor_pending_finalized_fulfills, vec_type), + (13, self.channel_type, required), }); Ok(()) @@ -5475,6 +5503,9 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel let mut announcement_sigs = None; let mut target_closing_feerate_sats_per_kw = None; let mut monitor_pending_finalized_fulfills = Some(Vec::new()); + // Prior to supporting channel type negotiation, all of our channels were static_remotekey + // only, so we default to that if none was written. + let mut channel_type = Some(ChannelTypeFeatures::only_static_remote_key()); read_tlv_fields!(reader, { (0, announcement_sigs, option), (1, minimum_depth, option), @@ -5483,8 +5514,16 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel (7, shutdown_scriptpubkey, option), (9, target_closing_feerate_sats_per_kw, option), (11, monitor_pending_finalized_fulfills, vec_type), + (13, channel_type, option), }); + let chan_features = channel_type.as_ref().unwrap(); + if chan_features.supports_unknown_bits() || chan_features.requires_unknown_bits() { + // If the channel was written by a new version and negotiated with features we don't + // understand yet, refuse to read it. + return Err(DecodeError::UnknownRequiredFeature); + } + let mut secp_ctx = Secp256k1::new(); secp_ctx.seeded_randomize(&keys_source.get_secure_random_bytes()); @@ -5577,6 +5616,8 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel #[cfg(any(test, feature = "fuzztarget"))] historical_inbound_htlc_fulfills, + + channel_type: channel_type.unwrap(), }) } } -- 2.39.5