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Time out incoming HTLCs when we reach cltv_expiry (+ test) #252

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Time out incoming HTLCs when we reach cltv_expiry (+ test) #252

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13 changes: 7 additions & 6 deletions src/ln/channel.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -264,7 +264,7 @@ pub(super) struct Channel {
monitor_pending_revoke_and_ack: bool,
monitor_pending_commitment_signed: bool,
monitor_pending_order: Option<RAACommitmentOrder>,
monitor_pending_forwards: Vec<(PendingForwardHTLCInfo, u64)>,
monitor_pending_forwards: Vec<(PendingForwardHTLCInfo, u64, u32)>,
monitor_pending_failures: Vec<(HTLCSource, [u8; 32], HTLCFailReason)>,

// pending_update_fee is filled when sending and receiving update_fee
Expand Down Expand Up @@ -1854,7 +1854,7 @@ impl Channel {
/// waiting on this revoke_and_ack. The generation of this new commitment_signed may also fail,
/// generating an appropriate error *after* the channel state has been updated based on the
/// revoke_and_ack message.
pub fn revoke_and_ack(&mut self, msg: &msgs::RevokeAndACK, fee_estimator: &FeeEstimator) -> Result<(Option<msgs::CommitmentUpdate>, Vec<(PendingForwardHTLCInfo, u64)>, Vec<(HTLCSource, [u8; 32], HTLCFailReason)>, Option<msgs::ClosingSigned>, ChannelMonitor), HandleError> {
pub fn revoke_and_ack(&mut self, msg: &msgs::RevokeAndACK, fee_estimator: &FeeEstimator) -> Result<(Option<msgs::CommitmentUpdate>, Vec<(PendingForwardHTLCInfo, u64, u32)>, Vec<(HTLCSource, [u8; 32], HTLCFailReason)>, Option<msgs::ClosingSigned>, ChannelMonitor), HandleError> {
if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
return Err(HandleError{err: "Got revoke/ACK message when channel was not in an operational state", action: None});
}
Expand Down Expand Up @@ -1942,7 +1942,7 @@ impl Channel {
}
},
PendingHTLCStatus::Forward(forward_info) => {
to_forward_infos.push((forward_info, htlc.htlc_id));
to_forward_infos.push((forward_info, htlc.htlc_id, htlc.cltv_expiry));
htlc.state = InboundHTLCState::Committed;
}
}
Expand Down Expand Up @@ -2152,7 +2152,7 @@ impl Channel {
/// Indicates that the latest ChannelMonitor update has been committed by the client
/// successfully and we should restore normal operation. Returns messages which should be sent
/// to the remote side.
pub fn monitor_updating_restored(&mut self) -> (Option<msgs::RevokeAndACK>, Option<msgs::CommitmentUpdate>, RAACommitmentOrder, Vec<(PendingForwardHTLCInfo, u64)>, Vec<(HTLCSource, [u8; 32], HTLCFailReason)>) {
pub fn monitor_updating_restored(&mut self) -> (Option<msgs::RevokeAndACK>, Option<msgs::CommitmentUpdate>, RAACommitmentOrder, Vec<(PendingForwardHTLCInfo, u64, u32)>, Vec<(HTLCSource, [u8; 32], HTLCFailReason)>) {
assert_eq!(self.channel_state & ChannelState::MonitorUpdateFailed as u32, ChannelState::MonitorUpdateFailed as u32);
self.channel_state &= !(ChannelState::MonitorUpdateFailed as u32);

Expand Down Expand Up @@ -3489,9 +3489,10 @@ impl Writeable for Channel {
}

(self.monitor_pending_forwards.len() as u64).write(writer)?;
for &(ref pending_forward, ref htlc_id) in self.monitor_pending_forwards.iter() {
for &(ref pending_forward, ref htlc_id, ref cltv_expiry) in self.monitor_pending_forwards.iter() {
pending_forward.write(writer)?;
htlc_id.write(writer)?;
cltv_expiry.write(writer)?;
}

(self.monitor_pending_failures.len() as u64).write(writer)?;
Expand Down Expand Up @@ -3670,7 +3671,7 @@ impl<R : ::std::io::Read> ReadableArgs<R, Arc<Logger>> for Channel {
let monitor_pending_forwards_count: u64 = Readable::read(reader)?;
let mut monitor_pending_forwards = Vec::with_capacity(cmp::min(monitor_pending_forwards_count as usize, OUR_MAX_HTLCS as usize));
for _ in 0..monitor_pending_forwards_count {
monitor_pending_forwards.push((Readable::read(reader)?, Readable::read(reader)?));
monitor_pending_forwards.push((Readable::read(reader)?, Readable::read(reader)?, Readable::read(reader)?));
}

let monitor_pending_failures_count: u64 = Readable::read(reader)?;
Expand Down
82 changes: 73 additions & 9 deletions src/ln/channelmanager.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,8 @@ mod channel_held_info {
pub(super) short_channel_id: u64,
pub(super) htlc_id: u64,
pub(super) incoming_packet_shared_secret: [u8; 32],
/// Only used to track expiry of claimable_htlcs and fail them backwards
pub(super) cltv_expiry: u32,
}

/// Tracks the inbound corresponding to an outbound HTLC
Expand Down Expand Up @@ -240,6 +242,7 @@ const MIN_HTLC_RELAY_HOLDING_CELL_MILLIS: u32 = 50;
struct HTLCForwardInfo {
prev_short_channel_id: u64,
prev_htlc_id: u64,
prev_cltv_expiry: u32,
forward_info: PendingForwardHTLCInfo,
}

Expand Down Expand Up @@ -1326,11 +1329,12 @@ impl ChannelManager {
Some(chan_id) => chan_id.clone(),
None => {
failed_forwards.reserve(pending_forwards.len());
for HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, forward_info } in pending_forwards.drain(..) {
for HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, forward_info, prev_cltv_expiry } in pending_forwards.drain(..) {
let htlc_source = HTLCSource::PreviousHopData(HTLCPreviousHopData {
short_channel_id: prev_short_channel_id,
htlc_id: prev_htlc_id,
incoming_packet_shared_secret: forward_info.incoming_shared_secret,
cltv_expiry: prev_cltv_expiry,
});
failed_forwards.push((htlc_source, forward_info.payment_hash, 0x4000 | 10, None));
}
Expand All @@ -1340,11 +1344,12 @@ impl ChannelManager {
let forward_chan = &mut channel_state.by_id.get_mut(&forward_chan_id).unwrap();

let mut add_htlc_msgs = Vec::new();
for HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, forward_info } in pending_forwards.drain(..) {
for HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, prev_cltv_expiry, forward_info } in pending_forwards.drain(..) {
let htlc_source = HTLCSource::PreviousHopData(HTLCPreviousHopData {
short_channel_id: prev_short_channel_id,
htlc_id: prev_htlc_id,
incoming_packet_shared_secret: forward_info.incoming_shared_secret,
cltv_expiry: prev_cltv_expiry,
});
match forward_chan.send_htlc(forward_info.amt_to_forward, forward_info.payment_hash, forward_info.outgoing_cltv_value, htlc_source.clone(), forward_info.onion_packet.unwrap()) {
Err(_e) => {
Expand Down Expand Up @@ -1398,11 +1403,12 @@ impl ChannelManager {
});
}
} else {
for HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, forward_info } in pending_forwards.drain(..) {
for HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, prev_cltv_expiry, forward_info } in pending_forwards.drain(..) {
let prev_hop_data = HTLCPreviousHopData {
short_channel_id: prev_short_channel_id,
htlc_id: prev_htlc_id,
incoming_packet_shared_secret: forward_info.incoming_shared_secret,
cltv_expiry: prev_cltv_expiry,
};
match channel_state.claimable_htlcs.entry(forward_info.payment_hash) {
hash_map::Entry::Occupied(mut entry) => entry.get_mut().push(prev_hop_data),
Expand Down Expand Up @@ -1471,7 +1477,7 @@ impl ChannelManager {
panic!("should have onion error packet here");
}
},
HTLCSource::PreviousHopData(HTLCPreviousHopData { short_channel_id, htlc_id, incoming_packet_shared_secret }) => {
HTLCSource::PreviousHopData(HTLCPreviousHopData { short_channel_id, htlc_id, incoming_packet_shared_secret, .. }) => {
let err_packet = match onion_error {
HTLCFailReason::Reason { failure_code, data } => {
let packet = ChannelManager::build_failure_packet(&incoming_packet_shared_secret, failure_code, &data[..]).encode();
Expand Down Expand Up @@ -2248,7 +2254,7 @@ impl ChannelManager {
}

#[inline]
fn forward_htlcs(&self, per_source_pending_forwards: &mut [(u64, Vec<(PendingForwardHTLCInfo, u64)>)]) {
fn forward_htlcs(&self, per_source_pending_forwards: &mut [(u64, Vec<(PendingForwardHTLCInfo, u64, u32)>)]) {
for &mut (prev_short_channel_id, ref mut pending_forwards) in per_source_pending_forwards {
let mut forward_event = None;
if !pending_forwards.is_empty() {
Expand All @@ -2257,13 +2263,13 @@ impl ChannelManager {
forward_event = Some(Instant::now() + Duration::from_millis(((rng::rand_f32() * 4.0 + 1.0) * MIN_HTLC_RELAY_HOLDING_CELL_MILLIS as f32) as u64));
channel_state.next_forward = forward_event.unwrap();
}
for (forward_info, prev_htlc_id) in pending_forwards.drain(..) {
for (forward_info, prev_htlc_id, prev_cltv_expiry) in pending_forwards.drain(..) {
match channel_state.forward_htlcs.entry(forward_info.short_channel_id) {
hash_map::Entry::Occupied(mut entry) => {
entry.get_mut().push(HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, forward_info });
entry.get_mut().push(HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, prev_cltv_expiry, forward_info });
},
hash_map::Entry::Vacant(entry) => {
entry.insert(vec!(HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, forward_info }));
entry.insert(vec!(HTLCForwardInfo { prev_short_channel_id, prev_htlc_id, prev_cltv_expiry, forward_info }));
}
}
}
Expand Down Expand Up @@ -2500,6 +2506,7 @@ impl ChainListener for ChannelManager {
fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) {
let _ = self.total_consistency_lock.read().unwrap();
let mut failed_channels = Vec::new();
let mut timed_out_htlcs = Vec::new();
{
let mut channel_lock = self.channel_state.lock().unwrap();
let channel_state = channel_lock.borrow_parts();
Expand Down Expand Up @@ -2567,10 +2574,27 @@ impl ChainListener for ChannelManager {
}
true
});
channel_state.claimable_htlcs.retain(|payment_hash, htlcs| {
htlcs.retain(|htlc| {
if htlc.cltv_expiry <= height { // XXX: Or <?
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Sorry what means "XXX: or <?" ? You want to substract a safe delay to height ?

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@TheBlueMatt TheBlueMatt Nov 16, 2018 •
edited
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Oops, lol, ffs, I really need to double-check my own commits before opening PRs, I blame sleep deprivation after 16 hours of being in a plane, thanks for reviewing...That was a note to myself that I'm not sure if the comparison was supposed to be <= or <, I'll double check and fix the PR.

timed_out_htlcs.push((HTLCSource::PreviousHopData(htlc.clone()), payment_hash.clone()));
false
} else { true }
});
!htlcs.is_empty()
});
}
for failure in failed_channels.drain(..) {
self.finish_force_close_channel(failure);
}
for (source, payment_hash) in timed_out_htlcs.drain(..) {
// Call it preimage_unknown as the issue, ultimately, is that the user failed to
// provide us a preimage within the cltv_expiry time window.
self.fail_htlc_backwards_internal(self.channel_state.lock().unwrap(), source, &payment_hash, HTLCFailReason::Reason {
failure_code: 0x4000 | 15,
data: Vec::new()
});
}
self.latest_block_height.store(height as usize, Ordering::Release);
*self.last_block_hash.try_lock().expect("block_(dis)connected must not be called in parallel") = header.bitcoin_hash();
}
Expand Down Expand Up @@ -2916,7 +2940,8 @@ impl<R: ::std::io::Read> Readable<R> for PendingHTLCStatus {
impl_writeable!(HTLCPreviousHopData, 0, {
short_channel_id,
htlc_id,
incoming_packet_shared_secret
incoming_packet_shared_secret,
cltv_expiry
});

impl Writeable for HTLCSource {
Expand Down Expand Up @@ -2984,6 +3009,7 @@ impl<R: ::std::io::Read> Readable<R> for HTLCFailReason {
impl_writeable!(HTLCForwardInfo, 0, {
prev_short_channel_id,
prev_htlc_id,
prev_cltv_expiry,
forward_info
});

Expand Down Expand Up @@ -7263,6 +7289,44 @@ mod tests {
do_test_monitor_temporary_update_fail(3 | 8 | 16);
}

#[test]
fn test_htlc_timeout() {
// If the user fails to claim/fail an HTLC within the HTLC CLTV timeout we fail it for them
// to avoid our counterparty failing the channel.
let secp_ctx = Secp256k1::new();
let nodes = create_network(2);

create_announced_chan_between_nodes(&nodes, 0, 1);
let (_, our_payment_hash) = route_payment(&nodes[0], &[&nodes[1]], 100000);

let mut header = BlockHeader { version: 0x20000000, prev_blockhash: Default::default(), merkle_root: Default::default(), time: 42, bits: 42, nonce: 42 };
nodes[0].chain_monitor.block_connected_checked(&header, 101, &[], &[]);
nodes[1].chain_monitor.block_connected_checked(&header, 101, &[], &[]);
for i in 102..TEST_FINAL_CLTV + 100 + 1 {
header.prev_blockhash = header.bitcoin_hash();
nodes[0].chain_monitor.block_connected_checked(&header, i, &[], &[]);
nodes[1].chain_monitor.block_connected_checked(&header, i, &[], &[]);
}

check_added_monitors!(nodes[1], 1);
let htlc_timeout_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
assert!(htlc_timeout_updates.update_add_htlcs.is_empty());
assert_eq!(htlc_timeout_updates.update_fail_htlcs.len(), 1);
assert!(htlc_timeout_updates.update_fail_malformed_htlcs.is_empty());
assert!(htlc_timeout_updates.update_fee.is_none());

nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &htlc_timeout_updates.update_fail_htlcs[0]).unwrap();
commitment_signed_dance!(nodes[0], nodes[1], htlc_timeout_updates.commitment_signed, false);
let events = nodes[0].node.get_and_clear_pending_events();
match events[0] {
Event::PaymentFailed { payment_hash, rejected_by_dest } => {
assert_eq!(payment_hash, our_payment_hash);
assert!(rejected_by_dest);
},
_ => panic!("Unexpected event"),
}
}

#[test]
fn test_invalid_channel_announcement() {
//Test BOLT 7 channel_announcement msg requirement for final node, gather data to build customed channel_announcement msgs
Expand Down
3 changes: 3 additions & 0 deletions src/util/events.rs
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Expand Up @@ -57,6 +57,9 @@ pub enum Event {
/// PaymentFailReason::AmountMismatch, respectively, to free up resources for this HTLC.
/// The amount paid should be considered 'incorrect' when it is less than or more than twice
/// the amount expected.
/// If you fail to call either ChannelManager::claim_funds of
/// ChannelManager::fail_htlc_backwards within the HTLC's timeout, the HTLC will be
/// automatically failed with PaymentFailReason::PreimageUnknown.
PaymentReceived {
/// The hash for which the preimage should be handed to the ChannelManager.
payment_hash: [u8; 32],
Expand Down