pub(crate) const CLTV_CLAIM_BUFFER: u32 = 6;
/// Number of blocks by which point we expect our counterparty to have seen new blocks on the
/// network and done a full update_fail_htlc/commitment_signed dance (+ we've updated all our
-/// copies of ChannelMonitors, including watchtowers).
-pub(crate) const HTLC_FAIL_TIMEOUT_BLOCKS: u32 = 3;
-/// Number of blocks we wait on seeing a confirmed HTLC-Timeout or previous revoked commitment
-/// transaction before we fail corresponding inbound HTLCs. This prevents us from failing backwards
-/// and then getting a reorg resulting in us losing money.
-pub(crate) const HTLC_FAIL_ANTI_REORG_DELAY: u32 = 6;
+/// copies of ChannelMonitors, including watchtowers). We could enforce the contract by failing
+/// at CLTV expiration height but giving a grace period to our peer may be profitable for us if he
+/// can provide an over-late preimage. Nevertheless, grace period has to be accounted in our
+/// CLTV_EXPIRY_DELTA to be secure. Following this policy we may decrease the rate of channel failures
+/// due to expiration but increase the cost of funds being locked longuer in case of failure.
+/// This delay also cover a low-power peer being slow to process blocks and so being behind us on
+/// accurate block height.
+/// In case of onchain failure to be pass backward we may see the last block of ANTI_REORG_DELAY
+/// with at worst this delay, so we are not only using this value as a mercy for them but also
+/// us as a safeguard to delay with enough time.
+pub(crate) const LATENCY_GRACE_PERIOD_BLOCKS: u32 = 3;
+/// Number of blocks we wait on seeing a HTLC output being solved before we fail corresponding inbound
+/// HTLCs. This prevents us from failing backwards and then getting a reorg resulting in us losing money.
+/// We use also this delay to be sure we can remove our in-flight claim txn from bump candidates buffer.
+/// It may cause spurrious generation of bumped claim txn but that's allright given the outpoint is already
+/// solved by a previous claim tx. What we want to avoid is reorg evicting our claim tx and us not
+/// keeping bumping another claim tx to solve the outpoint.
+pub(crate) const ANTI_REORG_DELAY: u32 = 6;
#[derive(Clone, PartialEq)]
enum Storage {
RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
}
+/// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
+/// once they mature to enough confirmations (ANTI_REORG_DELAY)
+#[derive(Clone, PartialEq)]
+enum OnchainEvent {
+ /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
+ /// bump-txn candidate buffer.
+ Claim {
+ outpoint: BitcoinOutPoint,
+ },
+ /// HTLC output getting solved by a timeout, at maturation we pass upstream payment source information to solve
+ /// inbound HTLC in backward channel. Note, in case of preimage, we pass info to upstream without delay as we can
+ /// only win from it, so it's never an OnchainEvent
+ HTLCUpdate {
+ htlc_update: (HTLCSource, PaymentHash),
+ },
+}
+
const SERIALIZATION_VERSION: u8 = 1;
const MIN_SERIALIZATION_VERSION: u8 = 1;
destination_script: Script,
- htlc_updated_waiting_threshold_conf: HashMap<u32, Vec<(HTLCSource, Option<PaymentPreimage>, PaymentHash)>>,
+ // Used to track onchain events, i.e transactions parts of channels confirmed on chain, on which
+ // we have to take actions once they reach enough confs. Key is a block height timer, i.e we enforce
+ // actions when we receive a block with given height. Actions depend on OnchainEvent type.
+ onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
// We simply modify last_block_hash in Channel's block_connected so that serialization is
// consistent but hopefully the users' copy handles block_connected in a consistent way.
self.current_local_signed_commitment_tx != other.current_local_signed_commitment_tx ||
self.payment_preimages != other.payment_preimages ||
self.destination_script != other.destination_script ||
- self.htlc_updated_waiting_threshold_conf != other.htlc_updated_waiting_threshold_conf
+ self.onchain_events_waiting_threshold_conf != other.onchain_events_waiting_threshold_conf
{
false
} else {
payment_preimages: HashMap::new(),
destination_script: destination_script,
- htlc_updated_waiting_threshold_conf: HashMap::new(),
+ onchain_events_waiting_threshold_conf: HashMap::new(),
last_block_hash: Default::default(),
secp_ctx: Secp256k1::new(),
self.last_block_hash.write(writer)?;
self.destination_script.write(writer)?;
- writer.write_all(&byte_utils::be64_to_array(self.htlc_updated_waiting_threshold_conf.len() as u64))?;
- for (ref target, ref updates) in self.htlc_updated_waiting_threshold_conf.iter() {
+ writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
+ for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
writer.write_all(&byte_utils::be32_to_array(**target))?;
- writer.write_all(&byte_utils::be64_to_array(updates.len() as u64))?;
- for ref update in updates.iter() {
- update.0.write(writer)?;
- update.1.write(writer)?;
- update.2.write(writer)?;
+ writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
+ for ev in events.iter() {
+ match *ev {
+ OnchainEvent::Claim { ref outpoint } => {
+ writer.write_all(&[0; 1])?;
+ outpoint.write(writer)?;
+ },
+ OnchainEvent::HTLCUpdate { ref htlc_update } => {
+ writer.write_all(&[1; 1])?;
+ htlc_update.0.write(writer)?;
+ htlc_update.1.write(writer)?;
+ }
+ }
}
}
if let Some(ref outpoints) = self.remote_claimable_outpoints.get($txid) {
for &(ref htlc, ref source_option) in outpoints.iter() {
if let &Some(ref source) = source_option {
- log_info!(self, "Failing HTLC with payment_hash {} from {} remote commitment tx due to broadcast of revoked remote commitment transaction, waiting for confirmation (at height {})", log_bytes!(htlc.payment_hash.0), $commitment_tx, height + HTLC_FAIL_ANTI_REORG_DELAY - 1);
- match self.htlc_updated_waiting_threshold_conf.entry(height + HTLC_FAIL_ANTI_REORG_DELAY - 1) {
+ log_info!(self, "Failing HTLC with payment_hash {} from {} remote commitment tx due to broadcast of revoked remote commitment transaction, waiting for confirmation (at height {})", log_bytes!(htlc.payment_hash.0), $commitment_tx, height + ANTI_REORG_DELAY - 1);
+ match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
hash_map::Entry::Occupied(mut entry) => {
let e = entry.get_mut();
- e.retain(|ref update| update.0 != **source);
- e.push(((**source).clone(), None, htlc.payment_hash.clone()));
+ e.retain(|ref event| {
+ match **event {
+ OnchainEvent::HTLCUpdate { ref htlc_update } => {
+ return htlc_update.0 != **source
+ },
+ _ => return true
+ }
+ });
+ e.push(OnchainEvent::HTLCUpdate { htlc_update: ((**source).clone(), htlc.payment_hash.clone())});
}
hash_map::Entry::Vacant(entry) => {
- entry.insert(vec![((**source).clone(), None, htlc.payment_hash.clone())]);
+ entry.insert(vec![OnchainEvent::HTLCUpdate { htlc_update: ((**source).clone(), htlc.payment_hash.clone())}]);
}
}
}
}
}
log_trace!(self, "Failing HTLC with payment_hash {} from {} remote commitment tx due to broadcast of remote commitment transaction", log_bytes!(htlc.payment_hash.0), $commitment_tx);
- match self.htlc_updated_waiting_threshold_conf.entry(height + HTLC_FAIL_ANTI_REORG_DELAY - 1) {
+ match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
hash_map::Entry::Occupied(mut entry) => {
let e = entry.get_mut();
- e.retain(|ref update| update.0 != **source);
- e.push(((**source).clone(), None, htlc.payment_hash.clone()));
+ e.retain(|ref event| {
+ match **event {
+ OnchainEvent::HTLCUpdate { ref htlc_update } => {
+ return htlc_update.0 != **source
+ },
+ _ => return true
+ }
+ });
+ e.push(OnchainEvent::HTLCUpdate { htlc_update: ((**source).clone(), htlc.payment_hash.clone())});
}
hash_map::Entry::Vacant(entry) => {
- entry.insert(vec![((**source).clone(), None, htlc.payment_hash.clone())]);
+ entry.insert(vec![OnchainEvent::HTLCUpdate { htlc_update: ((**source).clone(), htlc.payment_hash.clone())}]);
}
}
}
let mut watch_outputs = Vec::new();
macro_rules! wait_threshold_conf {
- ($height: expr, $source: expr, $update: expr, $commitment_tx: expr, $payment_hash: expr) => {
- log_info!(self, "Failing HTLC with payment_hash {} from {} local commitment tx due to broadcast of transaction, waiting confirmation (at height{})", log_bytes!($payment_hash.0), $commitment_tx, height + HTLC_FAIL_ANTI_REORG_DELAY - 1);
- match self.htlc_updated_waiting_threshold_conf.entry($height + HTLC_FAIL_ANTI_REORG_DELAY - 1) {
+ ($height: expr, $source: expr, $commitment_tx: expr, $payment_hash: expr) => {
+ log_trace!(self, "Failing HTLC with payment_hash {} from {} local commitment tx due to broadcast of transaction, waiting confirmation (at height{})", log_bytes!($payment_hash.0), $commitment_tx, height + ANTI_REORG_DELAY - 1);
+ match self.onchain_events_waiting_threshold_conf.entry($height + ANTI_REORG_DELAY - 1) {
hash_map::Entry::Occupied(mut entry) => {
let e = entry.get_mut();
- e.retain(|ref update| update.0 != $source);
- e.push(($source, $update, $payment_hash));
+ e.retain(|ref event| {
+ match **event {
+ OnchainEvent::HTLCUpdate { ref htlc_update } => {
+ return htlc_update.0 != $source
+ },
+ _ => return true
+ }
+ });
+ e.push(OnchainEvent::HTLCUpdate { htlc_update: ($source, $payment_hash)});
}
hash_map::Entry::Vacant(entry) => {
- entry.insert(vec![($source, $update, $payment_hash)]);
+ entry.insert(vec![OnchainEvent::HTLCUpdate { htlc_update: ($source, $payment_hash)}]);
}
}
}
for &(ref htlc, _, ref source) in &$local_tx.htlc_outputs {
if htlc.transaction_output_index.is_none() {
if let &Some(ref source) = source {
- wait_threshold_conf!(height, source.clone(), None, "lastest", htlc.payment_hash.clone());
+ wait_threshold_conf!(height, source.clone(), "lastest", htlc.payment_hash.clone());
}
}
}
}
}
}
- if let Some(updates) = self.htlc_updated_waiting_threshold_conf.remove(&height) {
- for update in updates {
- log_trace!(self, "HTLC {} failure update has get enough confirmation to be pass upstream", log_bytes!((update.2).0));
- htlc_updated.push(update);
+ if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
+ for ev in events {
+ match ev {
+ OnchainEvent::Claim { outpoint: _ } => {
+ },
+ OnchainEvent::HTLCUpdate { htlc_update } => {
+ log_trace!(self, "HTLC {} failure update has got enough confirmations to be passed upstream", log_bytes!((htlc_update.1).0));
+ htlc_updated.push((htlc_update.0, None, htlc_update.1));
+ },
+ }
}
}
self.last_block_hash = block_hash.clone();
}
fn block_disconnected(&mut self, height: u32, block_hash: &Sha256dHash) {
- if let Some(_) = self.htlc_updated_waiting_threshold_conf.remove(&(height + HTLC_FAIL_ANTI_REORG_DELAY - 1)) {
- //We discard htlc update there as failure-trigger tx (revoked commitment tx, non-revoked commitment tx, HTLC-timeout tx) has been disconnected
+ if let Some(_) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
+ //We may discard:
+ //- htlc update there as failure-trigger tx (revoked commitment tx, non-revoked commitment tx, HTLC-timeout tx) has been disconnected
+ //- our claim tx on a commitment tx output
}
self.last_block_hash = block_hash.clone();
}
// from us until we've reached the point where we go on-chain with the
// corresponding inbound HTLC, we must ensure that outbound HTLCs go on chain at
// least CLTV_CLAIM_BUFFER blocks prior to the inbound HTLC.
- // aka outbound_cltv + HTLC_FAIL_TIMEOUT_BLOCKS == height - CLTV_CLAIM_BUFFER
+ // aka outbound_cltv + LATENCY_GRACE_PERIOD_BLOCKS == height - CLTV_CLAIM_BUFFER
// inbound_cltv == height + CLTV_CLAIM_BUFFER
- // outbound_cltv + HTLC_FAIL_TIMEOUT_BLOCKS + CLTV_CLAIM_BUFFER <= inbound_cltv - CLTV_CLAIM_BUFFER
- // HTLC_FAIL_TIMEOUT_BLOCKS + 2*CLTV_CLAIM_BUFFER <= inbound_cltv - outbound_cltv
+ // outbound_cltv + LATENCY_GRACE_PERIOD_BLOCKS + CLTV_CLAIM_BUFFER <= inbound_cltv - CLTV_CLAIM_BUFFER
+ // LATENCY_GRACE_PERIOD_BLOCKS + 2*CLTV_CLAIM_BUFFER <= inbound_cltv - outbound_cltv
// CLTV_EXPIRY_DELTA <= inbound_cltv - outbound_cltv (by check in ChannelManager::decode_update_add_htlc_onion)
- // HTLC_FAIL_TIMEOUT_BLOCKS + 2*CLTV_CLAIM_BUFFER <= CLTV_EXPIRY_DELTA
+ // LATENCY_GRACE_PERIOD_BLOCKS + 2*CLTV_CLAIM_BUFFER <= CLTV_EXPIRY_DELTA
// The final, above, condition is checked for statically in channelmanager
// with CHECK_CLTV_EXPIRY_SANITY_2.
let htlc_outbound = $local_tx == htlc.offered;
- if ( htlc_outbound && htlc.cltv_expiry + HTLC_FAIL_TIMEOUT_BLOCKS <= height) ||
+ if ( htlc_outbound && htlc.cltv_expiry + LATENCY_GRACE_PERIOD_BLOCKS <= height) ||
(!htlc_outbound && htlc.cltv_expiry <= height + CLTV_CLAIM_BUFFER && self.payment_preimages.contains_key(&htlc.payment_hash)) {
log_info!(self, "Force-closing channel due to {} HTLC timeout, HTLC expiry is {}", if htlc_outbound { "outbound" } else { "inbound "}, htlc.cltv_expiry);
return true;
payment_preimage.0.copy_from_slice(&input.witness[1]);
htlc_updated.push((source, Some(payment_preimage), payment_hash));
} else {
- log_info!(self, "Failing HTLC with payment_hash {} timeout by a spend tx, waiting for confirmation (at height{})", log_bytes!(payment_hash.0), height + HTLC_FAIL_ANTI_REORG_DELAY - 1);
- match self.htlc_updated_waiting_threshold_conf.entry(height + HTLC_FAIL_ANTI_REORG_DELAY - 1) {
+ log_info!(self, "Failing HTLC with payment_hash {} timeout by a spend tx, waiting for confirmation (at height{})", log_bytes!(payment_hash.0), height + ANTI_REORG_DELAY - 1);
+ match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
hash_map::Entry::Occupied(mut entry) => {
let e = entry.get_mut();
- e.retain(|ref update| update.0 != source);
- e.push((source, None, payment_hash.clone()));
+ e.retain(|ref event| {
+ match **event {
+ OnchainEvent::HTLCUpdate { ref htlc_update } => {
+ return htlc_update.0 != source
+ },
+ _ => return true
+ }
+ });
+ e.push(OnchainEvent::HTLCUpdate { htlc_update: (source, payment_hash)});
}
hash_map::Entry::Vacant(entry) => {
- entry.insert(vec![(source, None, payment_hash)]);
+ entry.insert(vec![OnchainEvent::HTLCUpdate { htlc_update: (source, payment_hash)}]);
}
}
}
let destination_script = Readable::read(reader)?;
let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
- let mut htlc_updated_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
+ let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
for _ in 0..waiting_threshold_conf_len {
let height_target = Readable::read(reader)?;
- let updates_len: u64 = Readable::read(reader)?;
- let mut updates = Vec::with_capacity(cmp::min(updates_len as usize, MAX_ALLOC_SIZE / 128));
- for _ in 0..updates_len {
- let htlc_source = Readable::read(reader)?;
- let preimage = Readable::read(reader)?;
- let hash = Readable::read(reader)?;
- updates.push((htlc_source, preimage, hash));
+ let events_len: u64 = Readable::read(reader)?;
+ let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
+ for _ in 0..events_len {
+ let ev = match <u8 as Readable<R>>::read(reader)? {
+ 0 => {
+ let outpoint = Readable::read(reader)?;
+ OnchainEvent::Claim {
+ outpoint
+ }
+ },
+ 1 => {
+ let htlc_source = Readable::read(reader)?;
+ let hash = Readable::read(reader)?;
+ OnchainEvent::HTLCUpdate {
+ htlc_update: (htlc_source, hash)
+ }
+ },
+ _ => return Err(DecodeError::InvalidValue),
+ };
+ events.push(ev);
}
- htlc_updated_waiting_threshold_conf.insert(height_target, updates);
+ onchain_events_waiting_threshold_conf.insert(height_target, events);
}
Ok((last_block_hash.clone(), ChannelMonitor {
destination_script,
- htlc_updated_waiting_threshold_conf,
+ onchain_events_waiting_threshold_conf,
last_block_hash,
secp_ctx,
projects / rust-lightning / blobdiff