From: Duncan Dean Date: Tue, 13 Jun 2023 11:26:50 +0000 (+0200) Subject: Move `Channel::commit_tx_fee_msat` to file-level utilities X-Git-Tag: v0.0.116-alpha1~10^2~15 X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=08ee72be9d73a7ece8c1018229a15969348b9fbe;p=rust-lightning Move `Channel::commit_tx_fee_msat` to file-level utilities --- diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index 0f07ef82..00faeabb 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -1501,6 +1501,14 @@ fn commit_tx_fee_sat(feerate_per_kw: u32, num_htlcs: usize, opt_anchors: bool) - feerate_per_kw as u64 * (commitment_tx_base_weight(opt_anchors) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000 } +// Get the fee cost in MSATS of a commitment tx with a given number of HTLC outputs. +// Note that num_htlcs should not include dust HTLCs. +fn commit_tx_fee_msat(feerate_per_kw: u32, num_htlcs: usize, opt_anchors: bool) -> u64 { + // Note that we need to divide before multiplying to round properly, + // since the lowest denomination of bitcoin on-chain is the satoshi. + (commitment_tx_base_weight(opt_anchors) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * feerate_per_kw as u64 / 1000 * 1000 +} + // TODO: We should refactor this to be an Inbound/OutboundChannel until initial setup handshaking // has been completed, and then turn into a Channel to get compiler-time enforcement of things like // calling channel_id() before we're set up or things like get_outbound_funding_signed on an @@ -1698,7 +1706,7 @@ impl Channel { let feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal); let value_to_self_msat = channel_value_satoshis * 1000 - push_msat; - let commitment_tx_fee = Self::commit_tx_fee_msat(feerate, MIN_AFFORDABLE_HTLC_COUNT, channel_type.requires_anchors_zero_fee_htlc_tx()); + let commitment_tx_fee = commit_tx_fee_msat(feerate, MIN_AFFORDABLE_HTLC_COUNT, channel_type.requires_anchors_zero_fee_htlc_tx()); if value_to_self_msat < commitment_tx_fee { return Err(APIError::APIMisuseError{ err: format!("Funding amount ({}) can't even pay fee for initial commitment transaction fee of {}.", value_to_self_msat / 1000, commitment_tx_fee / 1000) }); } @@ -2032,7 +2040,7 @@ impl Channel { // check if the funder's amount for the initial commitment tx is sufficient // for full fee payment plus a few HTLCs to ensure the channel will be useful. let funders_amount_msat = msg.funding_satoshis * 1000 - msg.push_msat; - let commitment_tx_fee = Self::commit_tx_fee_msat(msg.feerate_per_kw, MIN_AFFORDABLE_HTLC_COUNT, opt_anchors) / 1000; + let commitment_tx_fee = commit_tx_fee_msat(msg.feerate_per_kw, MIN_AFFORDABLE_HTLC_COUNT, opt_anchors) / 1000; if funders_amount_msat / 1000 < commitment_tx_fee { return Err(ChannelError::Close(format!("Funding amount ({} sats) can't even pay fee for initial commitment transaction fee of {} sats.", funders_amount_msat / 1000, commitment_tx_fee))); } @@ -3157,14 +3165,6 @@ impl Channel { (context.holder_selected_channel_reserve_satoshis, context.counterparty_selected_channel_reserve_satoshis) } - // Get the fee cost in MSATS of a commitment tx with a given number of HTLC outputs. - // Note that num_htlcs should not include dust HTLCs. - fn commit_tx_fee_msat(feerate_per_kw: u32, num_htlcs: usize, opt_anchors: bool) -> u64 { - // Note that we need to divide before multiplying to round properly, - // since the lowest denomination of bitcoin on-chain is the satoshi. - (commitment_tx_base_weight(opt_anchors) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * feerate_per_kw as u64 / 1000 * 1000 - } - /// Get the commitment tx fee for the local's (i.e. our) next commitment transaction based on the /// number of pending HTLCs that are on track to be in our next commitment tx. /// @@ -3242,12 +3242,12 @@ impl Channel { } let num_htlcs = included_htlcs + addl_htlcs; - let res = Self::commit_tx_fee_msat(context.feerate_per_kw, num_htlcs, context.opt_anchors()); + let res = commit_tx_fee_msat(context.feerate_per_kw, num_htlcs, context.opt_anchors()); #[cfg(any(test, fuzzing))] { let mut fee = res; if fee_spike_buffer_htlc.is_some() { - fee = Self::commit_tx_fee_msat(context.feerate_per_kw, num_htlcs - 1, context.opt_anchors()); + fee = commit_tx_fee_msat(context.feerate_per_kw, num_htlcs - 1, context.opt_anchors()); } let total_pending_htlcs = context.pending_inbound_htlcs.len() + context.pending_outbound_htlcs.len() + context.holding_cell_htlc_updates.len(); @@ -3333,12 +3333,12 @@ impl Channel { } let num_htlcs = included_htlcs + addl_htlcs; - let res = Self::commit_tx_fee_msat(context.feerate_per_kw, num_htlcs, context.opt_anchors()); + let res = commit_tx_fee_msat(context.feerate_per_kw, num_htlcs, context.opt_anchors()); #[cfg(any(test, fuzzing))] { let mut fee = res; if fee_spike_buffer_htlc.is_some() { - fee = Self::commit_tx_fee_msat(context.feerate_per_kw, num_htlcs - 1, context.opt_anchors()); + fee = commit_tx_fee_msat(context.feerate_per_kw, num_htlcs - 1, context.opt_anchors()); } let total_pending_htlcs = context.pending_inbound_htlcs.len() + context.pending_outbound_htlcs.len(); let commitment_tx_info = CommitmentTxInfoCached { @@ -6184,7 +6184,7 @@ impl Channel { && info.next_holder_htlc_id == self.context.next_holder_htlc_id && info.next_counterparty_htlc_id == self.context.next_counterparty_htlc_id && info.feerate == self.context.feerate_per_kw { - let actual_fee = Self::commit_tx_fee_msat(self.context.feerate_per_kw, commitment_stats.num_nondust_htlcs, self.context.opt_anchors()); + let actual_fee = commit_tx_fee_msat(self.context.feerate_per_kw, commitment_stats.num_nondust_htlcs, self.context.opt_anchors()); assert_eq!(actual_fee, info.fee); } } @@ -7280,7 +7280,7 @@ mod tests { use crate::ln::channelmanager::{self, HTLCSource, PaymentId}; #[cfg(anchors)] use crate::ln::channel::InitFeatures; - use crate::ln::channel::{Channel, InboundHTLCOutput, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator}; + use crate::ln::channel::{Channel, InboundHTLCOutput, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator, commit_tx_fee_msat}; use crate::ln::channel::{MAX_FUNDING_SATOSHIS_NO_WUMBO, TOTAL_BITCOIN_SUPPLY_SATOSHIS, MIN_THEIR_CHAN_RESERVE_SATOSHIS}; use crate::ln::features::ChannelTypeFeatures; use crate::ln::msgs::{ChannelUpdate, DecodeError, UnsignedChannelUpdate, MAX_VALUE_MSAT}; @@ -7480,13 +7480,13 @@ mod tests { // the dust limit check. let htlc_candidate = HTLCCandidate::new(htlc_amount_msat, HTLCInitiator::LocalOffered); let local_commit_tx_fee = node_a_chan.next_local_commit_tx_fee_msat(htlc_candidate, None); - let local_commit_fee_0_htlcs = Channel::::commit_tx_fee_msat(node_a_chan.context.feerate_per_kw, 0, node_a_chan.context.opt_anchors()); + let local_commit_fee_0_htlcs = commit_tx_fee_msat(node_a_chan.context.feerate_per_kw, 0, node_a_chan.context.opt_anchors()); assert_eq!(local_commit_tx_fee, local_commit_fee_0_htlcs); // Finally, make sure that when Node A calculates the remote's commitment transaction fees, all // of the HTLCs are seen to be above the dust limit. node_a_chan.context.channel_transaction_parameters.is_outbound_from_holder = false; - let remote_commit_fee_3_htlcs = Channel::::commit_tx_fee_msat(node_a_chan.context.feerate_per_kw, 3, node_a_chan.context.opt_anchors()); + let remote_commit_fee_3_htlcs = commit_tx_fee_msat(node_a_chan.context.feerate_per_kw, 3, node_a_chan.context.opt_anchors()); let htlc_candidate = HTLCCandidate::new(htlc_amount_msat, HTLCInitiator::LocalOffered); let remote_commit_tx_fee = node_a_chan.next_remote_commit_tx_fee_msat(htlc_candidate, None); assert_eq!(remote_commit_tx_fee, remote_commit_fee_3_htlcs); @@ -7508,8 +7508,8 @@ mod tests { let config = UserConfig::default(); let mut chan = Channel::::new_outbound(&fee_est, &&keys_provider, &&keys_provider, node_id, &channelmanager::provided_init_features(&config), 10000000, 100000, 42, &config, 0, 42).unwrap(); - let commitment_tx_fee_0_htlcs = Channel::::commit_tx_fee_msat(chan.context.feerate_per_kw, 0, chan.context.opt_anchors()); - let commitment_tx_fee_1_htlc = Channel::::commit_tx_fee_msat(chan.context.feerate_per_kw, 1, chan.context.opt_anchors()); + let commitment_tx_fee_0_htlcs = commit_tx_fee_msat(chan.context.feerate_per_kw, 0, chan.context.opt_anchors()); + let commitment_tx_fee_1_htlc = commit_tx_fee_msat(chan.context.feerate_per_kw, 1, chan.context.opt_anchors()); // If HTLC_SUCCESS_TX_WEIGHT and HTLC_TIMEOUT_TX_WEIGHT were swapped: then this HTLC would be // counted as dust when it shouldn't be.