Enforce `max_balance_dust_htlc_msat` at HTLC reception/forward

[rust-lightning] / lightning / src / ln / channel.rs

diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index 95b0c573a7871369b0b4c9b0f02b55a3f3516430..d14b4fa953cb77c5211a78626fea4d6c4a150551 100644 (file)
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -2138,6 +2138,26 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                }
 
+               let exposure_dust_limit_timeout_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+               if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats {
+                       let on_counterparty_tx_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + msg.amount_msat;
+                       if on_counterparty_tx_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
+                                       on_counterparty_tx_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat());
+                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
+                       }
+               }
+
+               let exposure_dust_limit_success_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
+               if msg.amount_msat / 1000 < exposure_dust_limit_success_sats {
+                       let on_holder_tx_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + msg.amount_msat;
+                       if on_holder_tx_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
+                                       on_holder_tx_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat());
+                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
+                       }
+               }
+
                let pending_value_to_self_msat =
                        self.value_to_self_msat + inbound_stats.pending_htlcs_value_msat - removed_outbound_total_msat;
                let pending_remote_value_msat =
@@ -4219,6 +4239,24 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                }
 
+               let exposure_dust_limit_success_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+               if amount_msat / 1000 < exposure_dust_limit_success_sats {
+                       let on_counterparty_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + amount_msat;
+                       if on_counterparty_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                               return Err(ChannelError::Ignore(format!("Cannot send value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
+                                       on_counterparty_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat())));
+                       }
+               }
+
+               let exposure_dust_limit_timeout_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
+               if amount_msat / 1000 <  exposure_dust_limit_timeout_sats {
+                       let on_holder_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + amount_msat;
+                       if on_holder_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                               return Err(ChannelError::Ignore(format!("Cannot send value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
+                                       on_holder_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_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)));