// 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
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).
// 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
// sensitive to fee spikes.
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 {
+ 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());
// 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()));
}
}
// Create some initial channels
let (_, _, chan_id, funding_tx) =
- create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 11_000_000);
+ create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 12_000_000);
let funding_outpoint = OutPoint { txid: funding_tx.txid(), index: 0 };
assert_eq!(funding_outpoint.to_channel_id(), chan_id);
assert_eq!(revoked_local_txn[0].input.len(), 1);
assert_eq!(revoked_local_txn[0].input[0].previous_output.txid, funding_tx.txid());
if anchors {
- assert_eq!(revoked_local_txn[0].output[4].value, 10000); // to_self output
+ assert_eq!(revoked_local_txn[0].output[4].value, 11000); // to_self output
} else {
- assert_eq!(revoked_local_txn[0].output[2].value, 10000); // to_self output
+ assert_eq!(revoked_local_txn[0].output[2].value, 11000); // to_self output
}
// The to-be-revoked commitment tx should have two HTLCs, an output for each side, and an
let anchor_outputs_value = if anchors { channel::ANCHOR_OUTPUT_VALUE_SATOSHI * 2 } else { 0 };
let as_balances = sorted_vec(vec![Balance::ClaimableAwaitingConfirmations {
// to_remote output in B's revoked commitment
- amount_satoshis: 1_000_000 - 11_000 - 3_000 - commitment_tx_fee - anchor_outputs_value,
+ amount_satoshis: 1_000_000 - 12_000 - 3_000 - commitment_tx_fee - anchor_outputs_value,
confirmation_height: to_remote_conf_height,
}, Balance::CounterpartyRevokedOutputClaimable {
// to_self output in B's revoked commitment
- amount_satoshis: 10_000,
+ amount_satoshis: 11_000,
}, Balance::CounterpartyRevokedOutputClaimable { // HTLC 1
amount_satoshis: 3_000,
}, Balance::CounterpartyRevokedOutputClaimable { // HTLC 2
mine_transaction(&nodes[0], &as_htlc_claim_tx[0]);
assert_eq!(sorted_vec(vec![Balance::ClaimableAwaitingConfirmations {
// to_remote output in B's revoked commitment
- amount_satoshis: 1_000_000 - 11_000 - 3_000 - commitment_tx_fee - anchor_outputs_value,
+ amount_satoshis: 1_000_000 - 12_000 - 3_000 - commitment_tx_fee - anchor_outputs_value,
confirmation_height: to_remote_conf_height,
}, Balance::CounterpartyRevokedOutputClaimable {
// to_self output in B's revoked commitment
- amount_satoshis: 10_000,
+ amount_satoshis: 11_000,
}, Balance::CounterpartyRevokedOutputClaimable { // HTLC 2
amount_satoshis: 1_000,
}, Balance::ClaimableAwaitingConfirmations {
test_spendable_output(&nodes[0], &revoked_local_txn[0], false);
assert_eq!(sorted_vec(vec![Balance::CounterpartyRevokedOutputClaimable {
// to_self output to B
- amount_satoshis: 10_000,
+ amount_satoshis: 11_000,
}, Balance::CounterpartyRevokedOutputClaimable { // HTLC 2
amount_satoshis: 1_000,
}, Balance::ClaimableAwaitingConfirmations {
test_spendable_output(&nodes[0], &as_htlc_claim_tx[0], false);
assert_eq!(sorted_vec(vec![Balance::CounterpartyRevokedOutputClaimable {
// to_self output in B's revoked commitment
- amount_satoshis: 10_000,
+ amount_satoshis: 11_000,
}, Balance::CounterpartyRevokedOutputClaimable { // HTLC 2
amount_satoshis: 1_000,
}]),
connect_blocks(&nodes[0], ANTI_REORG_DELAY - 1);
assert_eq!(sorted_vec(vec![Balance::CounterpartyRevokedOutputClaimable {
// to_self output in B's revoked commitment
- amount_satoshis: 10_000,
+ amount_satoshis: 11_000,
}, Balance::CounterpartyRevokedOutputClaimable { // HTLC 2
amount_satoshis: 1_000,
}]),
mine_transaction(&nodes[0], &revoked_htlc_timeout_claim);
assert_eq!(sorted_vec(vec![Balance::CounterpartyRevokedOutputClaimable {
// to_self output in B's revoked commitment
- amount_satoshis: 10_000,
+ amount_satoshis: 11_000,
}, Balance::ClaimableAwaitingConfirmations {
amount_satoshis: revoked_htlc_timeout_claim.output[0].value,
confirmation_height: nodes[0].best_block_info().1 + ANTI_REORG_DELAY - 1,
use crate::sign::EntropySource;
use crate::chain::transaction::OutPoint;
use crate::events::{ClosureReason, Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentFailureReason, PaymentPurpose};
-use crate::ln::channel::EXPIRE_PREV_CONFIG_TICKS;
+use crate::ln::channel::{EXPIRE_PREV_CONFIG_TICKS, commit_tx_fee_msat, get_holder_selected_channel_reserve_satoshis, ANCHOR_OUTPUT_VALUE_SATOSHI};
use crate::ln::channelmanager::{BREAKDOWN_TIMEOUT, MPP_TIMEOUT_TICKS, MIN_CLTV_EXPIRY_DELTA, PaymentId, PaymentSendFailure, RecentPaymentDetails, RecipientOnionFields, HTLCForwardInfo, PendingHTLCRouting, PendingAddHTLCInfo};
-use crate::ln::features::Bolt11InvoiceFeatures;
+use crate::ln::features::{Bolt11InvoiceFeatures, ChannelTypeFeatures};
use crate::ln::{msgs, ChannelId, PaymentSecret, PaymentPreimage};
use crate::ln::msgs::ChannelMessageHandler;
use crate::ln::outbound_payment::{IDEMPOTENCY_TIMEOUT_TICKS, Retry};
do_test_payment_metadata_consistency(false, true);
do_test_payment_metadata_consistency(false, false);
}
+
+#[test]
+fn test_htlc_forward_considers_anchor_outputs_value() {
+ // Tests that:
+ //
+ // 1) Forwarding nodes don't forward HTLCs that would cause their balance to dip below the
+ // reserve when considering the value of anchor outputs.
+ //
+ // 2) Recipients of `update_add_htlc` properly reject HTLCs that would cause the initiator's
+ // balance to dip below the reserve when considering the value of anchor outputs.
+ let mut config = test_default_channel_config();
+ config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+ config.manually_accept_inbound_channels = true;
+ config.channel_config.forwarding_fee_base_msat = 0;
+ config.channel_config.forwarding_fee_proportional_millionths = 0;
+
+ // Set up a test network of three nodes that replicates a production failure leading to the
+ // discovery of this bug.
+ let chanmon_cfgs = create_chanmon_cfgs(3);
+ let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
+ let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[Some(config), Some(config), Some(config)]);
+ let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+
+ const CHAN_AMT: u64 = 1_000_000;
+ const PUSH_MSAT: u64 = 900_000_000;
+ create_announced_chan_between_nodes_with_value(&nodes, 0, 1, CHAN_AMT, 500_000_000);
+ let (_, _, chan_id_2, _) = create_announced_chan_between_nodes_with_value(&nodes, 1, 2, CHAN_AMT, PUSH_MSAT);
+
+ let channel_reserve_msat = get_holder_selected_channel_reserve_satoshis(CHAN_AMT, &config) * 1000;
+ let commitment_fee_msat = commit_tx_fee_msat(
+ *nodes[1].fee_estimator.sat_per_kw.lock().unwrap(), 2, &ChannelTypeFeatures::anchors_zero_htlc_fee_and_dependencies()
+ );
+ let anchor_outpus_value_msat = ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000;
+ let sendable_balance_msat = CHAN_AMT * 1000 - PUSH_MSAT - channel_reserve_msat - commitment_fee_msat - anchor_outpus_value_msat;
+ let channel_details = nodes[1].node.list_channels().into_iter().find(|channel| channel.channel_id == chan_id_2).unwrap();
+ assert!(sendable_balance_msat >= channel_details.next_outbound_htlc_minimum_msat);
+ assert!(sendable_balance_msat <= channel_details.next_outbound_htlc_limit_msat);
+
+ send_payment(&nodes[0], &[&nodes[1], &nodes[2]], sendable_balance_msat);
+ send_payment(&nodes[2], &[&nodes[1], &nodes[0]], sendable_balance_msat);
+
+ // Send out an HTLC that would cause the forwarding node to dip below its reserve when
+ // considering the value of anchor outputs.
+ let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(
+ nodes[0], nodes[2], sendable_balance_msat + anchor_outpus_value_msat
+ );
+ nodes[0].node.send_payment_with_route(
+ &route, payment_hash, RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)
+ ).unwrap();
+ check_added_monitors!(nodes[0], 1);
+
+ let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+ assert_eq!(events.len(), 1);
+ let mut update_add_htlc = if let MessageSendEvent::UpdateHTLCs { updates, .. } = events.pop().unwrap() {
+ nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &updates.update_add_htlcs[0]);
+ check_added_monitors(&nodes[1], 0);
+ commitment_signed_dance!(nodes[1], nodes[0], &updates.commitment_signed, false);
+ updates.update_add_htlcs[0].clone()
+ } else {
+ panic!("Unexpected event");
+ };
+
+ // The forwarding node should reject forwarding it as expected.
+ expect_pending_htlcs_forwardable!(nodes[1]);
+ expect_pending_htlcs_forwardable_and_htlc_handling_failed!(&nodes[1], vec![HTLCDestination::NextHopChannel {
+ node_id: Some(nodes[2].node.get_our_node_id()),
+ channel_id: chan_id_2
+ }]);
+ check_added_monitors(&nodes[1], 1);
+
+ let mut events = nodes[1].node.get_and_clear_pending_msg_events();
+ assert_eq!(events.len(), 1);
+ if let MessageSendEvent::UpdateHTLCs { updates, .. } = events.pop().unwrap() {
+ nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fail_htlcs[0]);
+ check_added_monitors(&nodes[0], 0);
+ commitment_signed_dance!(nodes[0], nodes[1], &updates.commitment_signed, false);
+ } else {
+ panic!("Unexpected event");
+ }
+
+ expect_payment_failed!(nodes[0], payment_hash, false);
+
+ // Assume that the forwarding node did forward it, and make sure the recipient rejects it as an
+ // invalid update and closes the channel.
+ update_add_htlc.channel_id = chan_id_2;
+ nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &update_add_htlc);
+ check_closed_event(&nodes[2], 1, ClosureReason::ProcessingError {
+ err: "Remote HTLC add would put them under remote reserve value".to_owned()
+ }, false, &[nodes[1].node.get_our_node_id()], 1_000_000);
+ check_closed_broadcast(&nodes[2], 1, true);
+ check_added_monitors(&nodes[2], 1);
+}
projects / rust-lightning / commitdiff