RemoteOffered,
}
+/// An enum gathering stats on pending HTLCs, either inbound or outbound side.
+struct HTLCStats {
+ pending_htlcs: u32,
+ pending_htlcs_value_msat: u64,
+ on_counterparty_tx_dust_exposure_msat: u64,
+ on_holder_tx_dust_exposure_msat: u64,
+}
+
/// Used when calculating whether we or the remote can afford an additional HTLC.
struct HTLCCandidate {
amount_msat: u64,
Ok(())
}
- /// Returns (inbound_htlc_count, htlc_inbound_value_msat)
- fn get_inbound_pending_htlc_stats(&self) -> (u32, u64) {
- let mut htlc_inbound_value_msat = 0;
+ /// Returns a HTLCStats about inbound pending htlcs
+ fn get_inbound_pending_htlc_stats(&self) -> HTLCStats {
+ let mut stats = HTLCStats {
+ pending_htlcs: self.pending_inbound_htlcs.len() as u32,
+ pending_htlcs_value_msat: 0,
+ on_counterparty_tx_dust_exposure_msat: 0,
+ on_holder_tx_dust_exposure_msat: 0,
+ };
+
+ let counterparty_dust_limit_timeout_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+ let holder_dust_limit_success_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
for ref htlc in self.pending_inbound_htlcs.iter() {
- htlc_inbound_value_msat += htlc.amount_msat;
+ stats.pending_htlcs_value_msat += htlc.amount_msat;
+ if htlc.amount_msat / 1000 < counterparty_dust_limit_timeout_sat {
+ stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+ }
+ if htlc.amount_msat / 1000 < holder_dust_limit_success_sat {
+ stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+ }
}
- (self.pending_inbound_htlcs.len() as u32, htlc_inbound_value_msat)
+ stats
}
- /// Returns (outbound_htlc_count, htlc_outbound_value_msat) *including* pending adds in our
- /// holding cell.
- fn get_outbound_pending_htlc_stats(&self) -> (u32, u64) {
- let mut htlc_outbound_value_msat = 0;
+ /// Returns a HTLCStats about pending outbound htlcs, *including* pending adds in our holding cell.
+ fn get_outbound_pending_htlc_stats(&self) -> HTLCStats {
+ let mut stats = HTLCStats {
+ pending_htlcs: self.pending_outbound_htlcs.len() as u32,
+ pending_htlcs_value_msat: 0,
+ on_counterparty_tx_dust_exposure_msat: 0,
+ on_holder_tx_dust_exposure_msat: 0,
+ };
+
+ let counterparty_dust_limit_success_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+ let holder_dust_limit_timeout_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
for ref htlc in self.pending_outbound_htlcs.iter() {
- htlc_outbound_value_msat += htlc.amount_msat;
+ stats.pending_htlcs_value_msat += htlc.amount_msat;
+ if htlc.amount_msat / 1000 < counterparty_dust_limit_success_sat {
+ stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+ }
+ if htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat {
+ stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+ }
}
- let mut htlc_outbound_count = self.pending_outbound_htlcs.len();
for update in self.holding_cell_htlc_updates.iter() {
if let &HTLCUpdateAwaitingACK::AddHTLC { ref amount_msat, .. } = update {
- htlc_outbound_count += 1;
- htlc_outbound_value_msat += amount_msat;
+ stats.pending_htlcs += 1;
+ stats.pending_htlcs_value_msat += amount_msat;
+ if *amount_msat / 1000 < counterparty_dust_limit_success_sat {
+ stats.on_counterparty_tx_dust_exposure_msat += amount_msat;
+ }
+ if *amount_msat / 1000 < holder_dust_limit_timeout_sat {
+ stats.on_holder_tx_dust_exposure_msat += amount_msat;
+ }
}
}
-
- (htlc_outbound_count as u32, htlc_outbound_value_msat)
+ stats
}
/// Get the available (ie not including pending HTLCs) inbound and outbound balance in msat.
(
cmp::max(self.channel_value_satoshis as i64 * 1000
- self.value_to_self_msat as i64
- - self.get_inbound_pending_htlc_stats().1 as i64
+ - self.get_inbound_pending_htlc_stats().pending_htlcs_value_msat as i64
- Self::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) as i64 * 1000,
0) as u64,
cmp::max(self.value_to_self_msat as i64
- - self.get_outbound_pending_htlc_stats().1 as i64
+ - self.get_outbound_pending_htlc_stats().pending_htlcs_value_msat as i64
- self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) as i64 * 1000,
0) as u64
)
return Err(ChannelError::Close(format!("Remote side tried to send less than our minimum HTLC value. Lower limit: ({}). Actual: ({})", self.holder_htlc_minimum_msat, msg.amount_msat)));
}
- let (inbound_htlc_count, htlc_inbound_value_msat) = self.get_inbound_pending_htlc_stats();
- if inbound_htlc_count + 1 > OUR_MAX_HTLCS as u32 {
+ let inbound_stats = self.get_inbound_pending_htlc_stats();
+ let outbound_stats = self.get_outbound_pending_htlc_stats();
+ if inbound_stats.pending_htlcs + 1 > OUR_MAX_HTLCS as u32 {
return Err(ChannelError::Close(format!("Remote tried to push more than our max accepted HTLCs ({})", OUR_MAX_HTLCS)));
}
let holder_max_htlc_value_in_flight_msat = Channel::<Signer>::get_holder_max_htlc_value_in_flight_msat(self.channel_value_satoshis);
- if htlc_inbound_value_msat + msg.amount_msat > holder_max_htlc_value_in_flight_msat {
+ if inbound_stats.pending_htlcs_value_msat + msg.amount_msat > holder_max_htlc_value_in_flight_msat {
return Err(ChannelError::Close(format!("Remote HTLC add would put them over our max HTLC value ({})", holder_max_htlc_value_in_flight_msat)));
}
// Check holder_selected_channel_reserve_satoshis (we're getting paid, so they have to at least meet
}
let pending_value_to_self_msat =
- self.value_to_self_msat + htlc_inbound_value_msat - removed_outbound_total_msat;
+ self.value_to_self_msat + inbound_stats.pending_htlcs_value_msat - removed_outbound_total_msat;
let pending_remote_value_msat =
self.channel_value_satoshis * 1000 - pending_value_to_self_msat;
if pending_remote_value_msat < msg.amount_msat {
cmp::max(self.config.cltv_expiry_delta, MIN_CLTV_EXPIRY_DELTA)
}
+ pub fn get_max_dust_htlc_exposure_msat(&self) -> u64 {
+ self.config.max_dust_htlc_exposure_msat
+ }
+
#[cfg(test)]
pub fn get_feerate(&self) -> u32 {
self.feerate_per_kw
}
+ pub fn get_dust_buffer_feerate(&self) -> u32 {
+ // When calculating our exposure to dust HTLCs, we assume that the channel feerate
+ // may, at any point, increase by at least 10 sat/vB (i.e 2530 sat/kWU) or 25%,
+ // whichever is higher. This ensures that we aren't suddenly exposed to significantly
+ // more dust balance if the feerate increases when we have several HTLCs pending
+ // which are near the dust limit.
+ cmp::max(2530, self.feerate_per_kw * 1250 / 1000)
+ }
+
pub fn get_cur_holder_commitment_transaction_number(&self) -> u64 {
self.cur_holder_commitment_transaction_number + 1
}
return Err(ChannelError::Ignore("Cannot send an HTLC while disconnected from channel counterparty".to_owned()));
}
- let (outbound_htlc_count, htlc_outbound_value_msat) = self.get_outbound_pending_htlc_stats();
- if outbound_htlc_count + 1 > self.counterparty_max_accepted_htlcs as u32 {
+ let inbound_stats = self.get_inbound_pending_htlc_stats();
+ let outbound_stats = self.get_outbound_pending_htlc_stats();
+ if outbound_stats.pending_htlcs + 1 > self.counterparty_max_accepted_htlcs as u32 {
return Err(ChannelError::Ignore(format!("Cannot push more than their max accepted HTLCs ({})", self.counterparty_max_accepted_htlcs)));
}
// Check their_max_htlc_value_in_flight_msat
- if htlc_outbound_value_msat + amount_msat > self.counterparty_max_htlc_value_in_flight_msat {
+ if outbound_stats.pending_htlcs_value_msat + amount_msat > self.counterparty_max_htlc_value_in_flight_msat {
return Err(ChannelError::Ignore(format!("Cannot send value that would put us over the max HTLC value in flight our peer will accept ({})", self.counterparty_max_htlc_value_in_flight_msat)));
}
}
}
- let pending_value_to_self_msat = self.value_to_self_msat - htlc_outbound_value_msat;
+ let pending_value_to_self_msat = self.value_to_self_msat - outbound_stats.pending_htlcs_value_msat;
if pending_value_to_self_msat < amount_msat {
return Err(ChannelError::Ignore(format!("Cannot send value that would overdraw remaining funds. Amount: {}, pending value to self {}", amount_msat, pending_value_to_self_msat)));
}
projects / rust-lightning / commitdiff