X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchannel.rs;h=f3632b41b471098392bf357e3a9e7220995588ce;hb=fba99b73bf5d23cb0ca554997dcb92dbaddd9cfc;hp=6a468f2d6fe9f71209691edfa7f0318a349d084a;hpb=be8797e17ab5c56582340d1f5e57f92477ede69d;p=rust-lightning diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index 6a468f2d..f3632b41 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -724,7 +724,7 @@ pub(super) struct ChannelContext where SP::Target: SignerProvider { cur_holder_commitment_transaction_number: u64, cur_counterparty_commitment_transaction_number: u64, - value_to_self_msat: u64, // Excluding all pending_htlcs, excluding fees + value_to_self_msat: u64, // Excluding all pending_htlcs, fees, and anchor outputs pending_inbound_htlcs: Vec, pending_outbound_htlcs: Vec, holding_cell_htlc_updates: Vec, @@ -1673,6 +1673,11 @@ impl ChannelContext where SP::Target: SignerProvider { let mut available_capacity_msat = outbound_capacity_msat; + let anchor_outputs_value_msat = if context.get_channel_type().supports_anchors_zero_fee_htlc_tx() { + ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000 + } else { + 0 + }; if context.is_outbound() { // We should mind channel commit tx fee when computing how much of the available capacity // can be used in the next htlc. Mirrors the logic in send_htlc. @@ -1687,14 +1692,19 @@ impl ChannelContext where SP::Target: SignerProvider { } let htlc_above_dust = HTLCCandidate::new(real_dust_limit_timeout_sat * 1000, HTLCInitiator::LocalOffered); - let max_reserved_commit_tx_fee_msat = FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE * context.next_local_commit_tx_fee_msat(htlc_above_dust, Some(())); + let mut max_reserved_commit_tx_fee_msat = context.next_local_commit_tx_fee_msat(htlc_above_dust, Some(())); let htlc_dust = HTLCCandidate::new(real_dust_limit_timeout_sat * 1000 - 1, HTLCInitiator::LocalOffered); - let min_reserved_commit_tx_fee_msat = FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE * context.next_local_commit_tx_fee_msat(htlc_dust, Some(())); + let mut min_reserved_commit_tx_fee_msat = context.next_local_commit_tx_fee_msat(htlc_dust, Some(())); + if !context.get_channel_type().supports_anchors_zero_fee_htlc_tx() { + max_reserved_commit_tx_fee_msat *= FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE; + min_reserved_commit_tx_fee_msat *= FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE; + } // We will first subtract the fee as if we were above-dust. Then, if the resulting // value ends up being below dust, we have this fee available again. In that case, // match the value to right-below-dust. - let mut capacity_minus_commitment_fee_msat: i64 = (available_capacity_msat as i64) - (max_reserved_commit_tx_fee_msat as i64); + let mut capacity_minus_commitment_fee_msat: i64 = available_capacity_msat as i64 - + max_reserved_commit_tx_fee_msat as i64 - anchor_outputs_value_msat as i64; if capacity_minus_commitment_fee_msat < (real_dust_limit_timeout_sat as i64) * 1000 { let one_htlc_difference_msat = max_reserved_commit_tx_fee_msat - min_reserved_commit_tx_fee_msat; debug_assert!(one_htlc_difference_msat != 0); @@ -1719,7 +1729,7 @@ impl ChannelContext where SP::Target: SignerProvider { let remote_balance_msat = (context.channel_value_satoshis * 1000 - context.value_to_self_msat) .saturating_sub(inbound_stats.pending_htlcs_value_msat); - if remote_balance_msat < max_reserved_commit_tx_fee_msat + holder_selected_chan_reserve_msat { + if remote_balance_msat < max_reserved_commit_tx_fee_msat + holder_selected_chan_reserve_msat + anchor_outputs_value_msat { // If another HTLC's fee would reduce the remote's balance below the reserve limit // we've selected for them, we can only send dust HTLCs. available_capacity_msat = cmp::min(available_capacity_msat, real_dust_limit_success_sat * 1000 - 1); @@ -2119,7 +2129,7 @@ fn commit_tx_fee_sat(feerate_per_kw: u32, num_htlcs: usize, channel_type_feature // 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, channel_type_features: &ChannelTypeFeatures) -> u64 { +pub(crate) fn commit_tx_fee_msat(feerate_per_kw: u32, num_htlcs: usize, channel_type_features: &ChannelTypeFeatures) -> 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(channel_type_features) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * feerate_per_kw as u64 / 1000 * 1000 @@ -2766,6 +2776,7 @@ impl Channel where if inbound_stats.pending_htlcs_value_msat + msg.amount_msat > self.context.holder_max_htlc_value_in_flight_msat { return Err(ChannelError::Close(format!("Remote HTLC add would put them over our max HTLC value ({})", self.context.holder_max_htlc_value_in_flight_msat))); } + // Check holder_selected_channel_reserve_satoshis (we're getting paid, so they have to at least meet // the reserve_satoshis we told them to always have as direct payment so that they lose // something if we punish them for broadcasting an old state). @@ -2825,30 +2836,40 @@ impl Channel where // Check that the remote can afford to pay for this HTLC on-chain at the current // feerate_per_kw, while maintaining their channel reserve (as required by the spec). - let remote_commit_tx_fee_msat = if self.context.is_outbound() { 0 } else { - let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered); - self.context.next_remote_commit_tx_fee_msat(htlc_candidate, None) // Don't include the extra fee spike buffer HTLC in calculations - }; - if pending_remote_value_msat - msg.amount_msat < remote_commit_tx_fee_msat { - return Err(ChannelError::Close("Remote HTLC add would not leave enough to pay for fees".to_owned())); - }; - - if pending_remote_value_msat - msg.amount_msat - remote_commit_tx_fee_msat < self.context.holder_selected_channel_reserve_satoshis * 1000 { - return Err(ChannelError::Close("Remote HTLC add would put them under remote reserve value".to_owned())); + { + let remote_commit_tx_fee_msat = if self.context.is_outbound() { 0 } else { + let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered); + self.context.next_remote_commit_tx_fee_msat(htlc_candidate, None) // Don't include the extra fee spike buffer HTLC in calculations + }; + let anchor_outputs_value_msat = if !self.context.is_outbound() && self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() { + ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000 + } else { + 0 + }; + if pending_remote_value_msat.saturating_sub(msg.amount_msat).saturating_sub(anchor_outputs_value_msat) < remote_commit_tx_fee_msat { + return Err(ChannelError::Close("Remote HTLC add would not leave enough to pay for fees".to_owned())); + }; + if pending_remote_value_msat.saturating_sub(msg.amount_msat).saturating_sub(remote_commit_tx_fee_msat).saturating_sub(anchor_outputs_value_msat) < self.context.holder_selected_channel_reserve_satoshis * 1000 { + return Err(ChannelError::Close("Remote HTLC add would put them under remote reserve value".to_owned())); + } } + let anchor_outputs_value_msat = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() { + ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000 + } else { + 0 + }; if !self.context.is_outbound() { - // `2 *` and `Some(())` is for the fee spike buffer we keep for the remote. This deviates from - // the spec because in the spec, the fee spike buffer requirement doesn't exist on the - // receiver's side, only on the sender's. - // Note that when we eventually remove support for fee updates and switch to anchor output - // fees, we will drop the `2 *`, since we no longer be as sensitive to fee spikes. But, keep - // the extra htlc when calculating the next remote commitment transaction fee as we should - // still be able to afford adding this HTLC plus one more future HTLC, regardless of being - // sensitive to fee spikes. + // `Some(())` is for the fee spike buffer we keep for the remote. This deviates from + // the spec because the fee spike buffer requirement doesn't exist on the receiver's + // side, only on the sender's. Note that with anchor outputs we are no longer as + // sensitive to fee spikes, so we need to account for them. let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered); - let remote_fee_cost_incl_stuck_buffer_msat = 2 * self.context.next_remote_commit_tx_fee_msat(htlc_candidate, Some(())); - if pending_remote_value_msat - msg.amount_msat - self.context.holder_selected_channel_reserve_satoshis * 1000 < remote_fee_cost_incl_stuck_buffer_msat { + let mut remote_fee_cost_incl_stuck_buffer_msat = self.context.next_remote_commit_tx_fee_msat(htlc_candidate, Some(())); + if !self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() { + remote_fee_cost_incl_stuck_buffer_msat *= FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE; + } + if pending_remote_value_msat.saturating_sub(msg.amount_msat).saturating_sub(self.context.holder_selected_channel_reserve_satoshis * 1000).saturating_sub(anchor_outputs_value_msat) < remote_fee_cost_incl_stuck_buffer_msat { // Note that if the pending_forward_status is not updated here, then it's because we're already failing // the HTLC, i.e. its status is already set to failing. log_info!(logger, "Attempting to fail HTLC due to fee spike buffer violation in channel {}. Rebalancing is required.", &self.context.channel_id()); @@ -2858,7 +2879,7 @@ impl Channel where // Check that they won't violate our local required channel reserve by adding this HTLC. let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered); let local_commit_tx_fee_msat = self.context.next_local_commit_tx_fee_msat(htlc_candidate, None); - if self.context.value_to_self_msat < self.context.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 + local_commit_tx_fee_msat { + if self.context.value_to_self_msat < self.context.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 + local_commit_tx_fee_msat + anchor_outputs_value_msat { return Err(ChannelError::Close("Cannot accept HTLC that would put our balance under counterparty-announced channel reserve value".to_owned())); } } @@ -5721,16 +5742,16 @@ impl OutboundV1Channel where SP::Target: SignerProvider { let channel_type = Self::get_initial_channel_type(&config, their_features); debug_assert!(channel_type.is_subset(&channelmanager::provided_channel_type_features(&config))); - let commitment_conf_target = if channel_type.supports_anchors_zero_fee_htlc_tx() { - ConfirmationTarget::AnchorChannelFee + let (commitment_conf_target, anchor_outputs_value_msat) = if channel_type.supports_anchors_zero_fee_htlc_tx() { + (ConfirmationTarget::AnchorChannelFee, ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000) } else { - ConfirmationTarget::NonAnchorChannelFee + (ConfirmationTarget::NonAnchorChannelFee, 0) }; let commitment_feerate = fee_estimator.bounded_sat_per_1000_weight(commitment_conf_target); let value_to_self_msat = channel_value_satoshis * 1000 - push_msat; let commitment_tx_fee = commit_tx_fee_msat(commitment_feerate, MIN_AFFORDABLE_HTLC_COUNT, &channel_type); - if value_to_self_msat < commitment_tx_fee { + if value_to_self_msat.saturating_sub(anchor_outputs_value_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) }); } @@ -6347,13 +6368,18 @@ impl InboundV1Channel where SP::Target: SignerProvider { // 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 anchor_outputs_value = if channel_type.supports_anchors_zero_fee_htlc_tx() { + ANCHOR_OUTPUT_VALUE_SATOSHI * 2 + } else { + 0 + }; let funders_amount_msat = msg.funding_satoshis * 1000 - msg.push_msat; let commitment_tx_fee = commit_tx_fee_msat(msg.feerate_per_kw, MIN_AFFORDABLE_HTLC_COUNT, &channel_type) / 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))); + if (funders_amount_msat / 1000).saturating_sub(anchor_outputs_value) < 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).saturating_sub(anchor_outputs_value), commitment_tx_fee))); } - let to_remote_satoshis = funders_amount_msat / 1000 - commitment_tx_fee; + let to_remote_satoshis = funders_amount_msat / 1000 - commitment_tx_fee - anchor_outputs_value; // While it's reasonable for us to not meet the channel reserve initially (if they don't // want to push much to us), our counterparty should always have more than our reserve. if to_remote_satoshis < holder_selected_channel_reserve_satoshis {