From 9469ce0f3877843997f382da2e04e603335e37d7 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Thu, 19 May 2022 01:50:37 +0000 Subject: [PATCH] Track HTLC-Success/HTLC-Timeout claims of revoked outputs When a counterparty broadcasts a revoked commitment transaction, followed immediately by HTLC-Success/-Timeout spends thereof, we'd like to have an `onchain_events_awaiting_threshold_conf` entry for them. This does so using the `HTLCSpendConfirmation` entry, giving it (slightly) new meaning. Because all existing uses of `HTLCSpendConfirmation` already check if the relevant commitment transaction is revoked first, this should be trivially backwards compatible. We will ultimately figure out if something is being spent via the `OnchainTxHandler`, but to do so we need to look up the output via the HTLC transaction txid, which this allows us to do. --- lightning/src/chain/channelmonitor.rs | 44 ++++++++++++--------------- 1 file changed, 20 insertions(+), 24 deletions(-) diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs index 4d109294c..0d1c458bc 100644 --- a/lightning/src/chain/channelmonitor.rs +++ b/lightning/src/chain/channelmonitor.rs @@ -369,6 +369,8 @@ enum OnchainEvent { /// transaction which appeared on chain. commitment_tx_output_idx: Option, }, + /// An output waiting on [`ANTI_REORG_DELAY`] confirmations before we hand the user the + /// [`SpendableOutputDescriptor`]. MaturingOutput { descriptor: SpendableOutputDescriptor, }, @@ -390,6 +392,9 @@ enum OnchainEvent { /// * an inbound HTLC is claimed by us (with a preimage). /// * a revoked-state HTLC transaction was broadcasted, which was claimed by the revocation /// signature. + /// * a revoked-state HTLC transaction was broadcasted, which was claimed by an + /// HTLC-Success/HTLC-Failure transaction (and is still claimable with a revocation + /// signature). HTLCSpendConfirmation { commitment_tx_output_idx: u32, /// If the claim was made by either party with a preimage, this is filled in @@ -2965,7 +2970,7 @@ impl ChannelMonitorImpl { log_error!(logger, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}!", $tx_info, input.previous_output.txid, input.previous_output.vout, tx.txid(), if outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($htlc.payment_hash.0), - if revocation_sig_claim { "revocation sig" } else { "preimage claim after we'd passed the HTLC resolution back" }); + if revocation_sig_claim { "revocation sig" } else { "preimage claim after we'd passed the HTLC resolution back. We can likely claim the HTLC output with a revocation claim" }); } else { log_info!(logger, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}", $tx_info, input.previous_output.txid, input.previous_output.vout, tx.txid(), @@ -3012,29 +3017,20 @@ impl ChannelMonitorImpl { if payment_data.is_none() { log_claim!($tx_info, $holder_tx, htlc_output, false); let outbound_htlc = $holder_tx == htlc_output.offered; - if !outbound_htlc || revocation_sig_claim { - self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry { - txid: tx.txid(), height, transaction: Some(tx.clone()), - event: OnchainEvent::HTLCSpendConfirmation { - commitment_tx_output_idx: input.previous_output.vout, - preimage: if accepted_preimage_claim || offered_preimage_claim { - Some(payment_preimage) } else { None }, - // If this is a payment to us (!outbound_htlc, above), - // wait for the CSV delay before dropping the HTLC from - // claimable balance if the claim was an HTLC-Success - // transaction. - on_to_local_output_csv: if accepted_preimage_claim { - Some(self.on_holder_tx_csv) } else { None }, - }, - }); - } else { - // Outbound claims should always have payment_data, unless - // we've already failed the HTLC as the commitment transaction - // which was broadcasted was revoked. In that case, we should - // spend the HTLC output here immediately, and expose that fact - // as a Balance, something which we do not yet do. - // TODO: Track the above as claimable! - } + self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry { + txid: tx.txid(), height, transaction: Some(tx.clone()), + event: OnchainEvent::HTLCSpendConfirmation { + commitment_tx_output_idx: input.previous_output.vout, + preimage: if accepted_preimage_claim || offered_preimage_claim { + Some(payment_preimage) } else { None }, + // If this is a payment to us (ie !outbound_htlc), wait for + // the CSV delay before dropping the HTLC from claimable + // balance if the claim was an HTLC-Success transaction (ie + // accepted_preimage_claim). + on_to_local_output_csv: if accepted_preimage_claim && !outbound_htlc { + Some(self.on_holder_tx_csv) } else { None }, + }, + }); continue 'outer_loop; } } -- 2.39.5