// licenses.
use bitcoin::blockdata::script::{Script,Builder};
-use bitcoin::blockdata::transaction::{TxIn, TxOut, Transaction, SigHashType};
+use bitcoin::blockdata::transaction::{Transaction, SigHashType};
use bitcoin::util::bip143;
use bitcoin::consensus::encode;
use ln::msgs::{DecodeError, OptionalField, DataLossProtect};
use ln::script::ShutdownScript;
use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT};
-use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor};
+use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor, ClosingTransaction};
use ln::chan_utils;
use chain::BestBlock;
use chain::chaininterface::{FeeEstimator,ConfirmationTarget};
use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, HTLC_FAIL_BACK_BUFFER};
use chain::transaction::{OutPoint, TransactionData};
use chain::keysinterface::{Sign, KeysInterface};
-use util::transaction_utils;
use util::ser::{Readable, ReadableArgs, Writeable, Writer, VecWriter};
use util::logger::Logger;
use util::errors::APIError;
RemoteShutdownSent = 1 << 10,
/// Flag which is set on ChannelFunded or FundingSent after sending a shutdown message. At this
/// point, we may not add any new HTLCs to the channel.
- /// TODO: Investigate some kind of timeout mechanism by which point the remote end must provide
- /// us their shutdown.
LocalShutdownSent = 1 << 11,
/// We've successfully negotiated a closing_signed dance. At this point ChannelManager is about
/// to drop us, but we store this anyway.
monitor_pending_forwards: Vec<(PendingHTLCInfo, u64)>,
monitor_pending_failures: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
- // pending_update_fee is filled when sending and receiving update_fee
- // For outbound channel, feerate_per_kw is updated with the value from
- // pending_update_fee when revoke_and_ack is received
+ // pending_update_fee is filled when sending and receiving update_fee.
//
- // For inbound channel, feerate_per_kw is updated when it receives
- // commitment_signed and revoke_and_ack is generated
- // The pending value is kept when another pair of update_fee and commitment_signed
- // is received during AwaitingRemoteRevoke and relieved when the expected
- // revoke_and_ack is received and new commitment_signed is generated to be
- // sent to the funder. Otherwise, the pending value is removed when receiving
- // commitment_signed.
+ // Because it follows the same commitment flow as HTLCs, `FeeUpdateState` is either `Outbound`
+ // or matches a subset of the `InboundHTLCOutput` variants. It is then updated/used when
+ // generating new commitment transactions with exactly the same criteria as inbound/outbound
+ // HTLCs with similar state.
pending_update_fee: Option<(u32, FeeUpdateState)>,
- // update_fee() during ChannelState::AwaitingRemoteRevoke is hold in
- // holdina_cell_update_fee then moved to pending_udpate_fee when revoke_and_ack
- // is received. holding_cell_update_fee is updated when there are additional
- // update_fee() during ChannelState::AwaitingRemoteRevoke.
+ // If a `send_update_fee()` call is made with ChannelState::AwaitingRemoteRevoke set, we place
+ // it here instead of `pending_update_fee` in the same way as we place outbound HTLC updates in
+ // `holding_cell_htlc_updates` instead of `pending_outbound_htlcs`. It is released into
+ // `pending_update_fee` with the same criteria as outbound HTLC updates but can be updated by
+ // further `send_update_fee` calls, dropping the previous holding cell update entirely.
holding_cell_update_fee: Option<u32>,
next_holder_htlc_id: u64,
next_counterparty_htlc_id: u64,
counterparty_max_commitment_tx_output: Mutex<(u64, u64)>,
last_sent_closing_fee: Option<(u64, Signature)>, // (fee, holder_sig)
- closing_fee_limits: Option<(u64, u64)>,
target_closing_feerate_sats_per_kw: Option<u32>,
/// If our counterparty sent us a closing_signed while we were waiting for a `ChannelMonitor`
/// closing_signed message and handling it in `maybe_propose_closing_signed`.
pending_counterparty_closing_signed: Option<msgs::ClosingSigned>,
+ /// The minimum and maximum absolute fee we are willing to place on the closing transaction.
+ /// These are set once we reach `closing_negotiation_ready`.
+ #[cfg(test)]
+ pub(crate) closing_fee_limits: Option<(u64, u64)>,
+ #[cfg(not(test))]
+ closing_fee_limits: Option<(u64, u64)>,
+
/// The hash of the block in which the funding transaction was included.
funding_tx_confirmed_in: Option<BlockHash>,
funding_tx_confirmation_height: u32,
commitment_secrets: CounterpartyCommitmentSecrets,
channel_update_status: ChannelUpdateStatus,
+ /// Once we reach `closing_negotiation_ready`, we set this, indicating if closing_signed does
+ /// not complete within a single timer tick (one minute), we should force-close the channel.
+ /// This prevents us from keeping unusable channels around forever if our counterparty wishes
+ /// to DoS us.
+ /// Note that this field is reset to false on deserialization to give us a chance to connect to
+ /// our peer and start the closing_signed negotiation fresh.
+ closing_signed_in_flight: bool,
/// Our counterparty's channel_announcement signatures provided in announcement_signatures.
/// This can be used to rebroadcast the channel_announcement message later.
#[cfg(test)]
pub const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172;
-/// Maximmum `funding_satoshis` value, according to the BOLT #2 specification
+pub const ANCHOR_OUTPUT_VALUE_SATOSHI: u64 = 330;
+
+/// Maximum `funding_satoshis` value, according to the BOLT #2 specification
/// it's 2^24.
pub const MAX_FUNDING_SATOSHIS: u64 = 1 << 24;
commitment_secrets: CounterpartyCommitmentSecrets::new(),
channel_update_status: ChannelUpdateStatus::Enabled,
+ closing_signed_in_flight: false,
announcement_sigs: None,
commitment_secrets: CounterpartyCommitmentSecrets::new(),
channel_update_status: ChannelUpdateStatus::Enabled,
+ closing_signed_in_flight: false,
announcement_sigs: None,
let mut value_to_a = if local { value_to_self } else { value_to_remote };
let mut value_to_b = if local { value_to_remote } else { value_to_self };
+ let (funding_pubkey_a, funding_pubkey_b) = if local {
+ (self.get_holder_pubkeys().funding_pubkey, self.get_counterparty_pubkeys().funding_pubkey)
+ } else {
+ (self.get_counterparty_pubkeys().funding_pubkey, self.get_holder_pubkeys().funding_pubkey)
+ };
if value_to_a >= (broadcaster_dust_limit_satoshis as i64) {
log_trace!(logger, " ...including {} output with value {}", if local { "to_local" } else { "to_remote" }, value_to_a);
let tx = CommitmentTransaction::new_with_auxiliary_htlc_data(commitment_number,
value_to_a as u64,
value_to_b as u64,
+ false,
+ funding_pubkey_a,
+ funding_pubkey_b,
keys.clone(),
feerate_per_kw,
&mut included_non_dust_htlcs,
}
#[inline]
- fn build_closing_transaction(&self, proposed_total_fee_satoshis: u64, skip_remote_output: bool) -> (Transaction, u64) {
- let txins = {
- let mut ins: Vec<TxIn> = Vec::new();
- ins.push(TxIn {
- previous_output: self.funding_outpoint().into_bitcoin_outpoint(),
- script_sig: Script::new(),
- sequence: 0xffffffff,
- witness: Vec::new(),
- });
- ins
- };
-
+ fn build_closing_transaction(&self, proposed_total_fee_satoshis: u64, skip_remote_output: bool) -> (ClosingTransaction, u64) {
assert!(self.pending_inbound_htlcs.is_empty());
assert!(self.pending_outbound_htlcs.is_empty());
assert!(self.pending_update_fee.is_none());
- let mut txouts: Vec<(TxOut, ())> = Vec::new();
let mut total_fee_satoshis = proposed_total_fee_satoshis;
- let value_to_self: i64 = (self.value_to_self_msat as i64) / 1000 - if self.is_outbound() { total_fee_satoshis as i64 } else { 0 };
- let value_to_remote: i64 = ((self.channel_value_satoshis * 1000 - self.value_to_self_msat) as i64 / 1000) - if self.is_outbound() { 0 } else { total_fee_satoshis as i64 };
+ let mut value_to_holder: i64 = (self.value_to_self_msat as i64) / 1000 - if self.is_outbound() { total_fee_satoshis as i64 } else { 0 };
+ let mut value_to_counterparty: i64 = ((self.channel_value_satoshis * 1000 - self.value_to_self_msat) as i64 / 1000) - if self.is_outbound() { 0 } else { total_fee_satoshis as i64 };
- if value_to_self < 0 {
+ if value_to_holder < 0 {
assert!(self.is_outbound());
- total_fee_satoshis += (-value_to_self) as u64;
- } else if value_to_remote < 0 {
+ total_fee_satoshis += (-value_to_holder) as u64;
+ } else if value_to_counterparty < 0 {
assert!(!self.is_outbound());
- total_fee_satoshis += (-value_to_remote) as u64;
+ total_fee_satoshis += (-value_to_counterparty) as u64;
}
- if !skip_remote_output && value_to_remote as u64 > self.holder_dust_limit_satoshis {
- txouts.push((TxOut {
- script_pubkey: self.counterparty_shutdown_scriptpubkey.clone().unwrap(),
- value: value_to_remote as u64
- }, ()));
+ if skip_remote_output || value_to_counterparty as u64 <= self.holder_dust_limit_satoshis {
+ value_to_counterparty = 0;
}
- assert!(self.shutdown_scriptpubkey.is_some());
- if value_to_self as u64 > self.holder_dust_limit_satoshis {
- txouts.push((TxOut {
- script_pubkey: self.get_closing_scriptpubkey(),
- value: value_to_self as u64
- }, ()));
+ if value_to_holder as u64 <= self.holder_dust_limit_satoshis {
+ value_to_holder = 0;
}
- transaction_utils::sort_outputs(&mut txouts, |_, _| { cmp::Ordering::Equal }); // Ordering doesnt matter if they used our pubkey...
-
- let mut outputs: Vec<TxOut> = Vec::new();
- for out in txouts.drain(..) {
- outputs.push(out.0);
- }
+ assert!(self.shutdown_scriptpubkey.is_some());
+ let holder_shutdown_script = self.get_closing_scriptpubkey();
+ let counterparty_shutdown_script = self.counterparty_shutdown_scriptpubkey.clone().unwrap();
+ let funding_outpoint = self.funding_outpoint().into_bitcoin_outpoint();
- (Transaction {
- version: 2,
- lock_time: 0,
- input: txins,
- output: outputs,
- }, total_fee_satoshis)
+ let closing_transaction = ClosingTransaction::new(value_to_holder as u64, value_to_counterparty as u64, holder_shutdown_script, counterparty_shutdown_script, funding_outpoint);
+ (closing_transaction, total_fee_satoshis)
}
fn funding_outpoint(&self) -> OutPoint {
self.counterparty_funding_pubkey()
);
+ self.holder_signer.validate_holder_commitment(&holder_commitment_tx)
+ .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?;
+
// Now that we're past error-generating stuff, update our local state:
let funding_redeemscript = self.get_funding_redeemscript();
self.counterparty_funding_pubkey()
);
+ self.holder_signer.validate_holder_commitment(&holder_commitment_tx)
+ .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?;
+
let funding_redeemscript = self.get_funding_redeemscript();
let funding_txo = self.get_funding_txo().unwrap();
);
let next_per_commitment_point = self.holder_signer.get_per_commitment_point(self.cur_holder_commitment_transaction_number - 1, &self.secp_ctx);
+ self.holder_signer.validate_holder_commitment(&holder_commitment_tx)
+ .map_err(|_| (None, ChannelError::Close("Failed to validate our commitment".to_owned())))?;
let per_commitment_secret = self.holder_signer.release_commitment_secret(self.cur_holder_commitment_transaction_number + 1);
// Update state now that we've passed all the can-fail calls...
return Err(ChannelError::Close("Peer sent revoke_and_ack after we'd started exchanging closing_signeds".to_owned()));
}
+ let secret = secp_check!(SecretKey::from_slice(&msg.per_commitment_secret), "Peer provided an invalid per_commitment_secret".to_owned());
+
if let Some(counterparty_prev_commitment_point) = self.counterparty_prev_commitment_point {
- if PublicKey::from_secret_key(&self.secp_ctx, &secp_check!(SecretKey::from_slice(&msg.per_commitment_secret), "Peer provided an invalid per_commitment_secret".to_owned())) != counterparty_prev_commitment_point {
+ if PublicKey::from_secret_key(&self.secp_ctx, &secret) != counterparty_prev_commitment_point {
return Err(ChannelError::Close("Got a revoke commitment secret which didn't correspond to their current pubkey".to_owned()));
}
}
*self.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = None;
}
+ self.holder_signer.validate_counterparty_revocation(
+ self.cur_counterparty_commitment_transaction_number + 1,
+ &secret
+ ).map_err(|_| ChannelError::Close("Failed to validate revocation from peer".to_owned()))?;
+
self.commitment_secrets.provide_secret(self.cur_counterparty_commitment_transaction_number + 1, msg.per_commitment_secret)
.map_err(|_| ChannelError::Close("Previous secrets did not match new one".to_owned()))?;
self.latest_monitor_update_id += 1;
self.closing_fee_limits.clone().unwrap()
}
+ /// Returns true if we're ready to commence the closing_signed negotiation phase. This is true
+ /// after both sides have exchanged a `shutdown` message and all HTLCs have been drained. At
+ /// this point if we're the funder we should send the initial closing_signed, and in any case
+ /// shutdown should complete within a reasonable timeframe.
+ fn closing_negotiation_ready(&self) -> bool {
+ self.pending_inbound_htlcs.is_empty() && self.pending_outbound_htlcs.is_empty() &&
+ self.channel_state &
+ (BOTH_SIDES_SHUTDOWN_MASK | ChannelState::AwaitingRemoteRevoke as u32 |
+ ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateFailed as u32)
+ == BOTH_SIDES_SHUTDOWN_MASK &&
+ self.pending_update_fee.is_none()
+ }
+
+ /// Checks if the closing_signed negotiation is making appropriate progress, possibly returning
+ /// an Err if no progress is being made and the channel should be force-closed instead.
+ /// Should be called on a one-minute timer.
+ pub fn timer_check_closing_negotiation_progress(&mut self) -> Result<(), ChannelError> {
+ if self.closing_negotiation_ready() {
+ if self.closing_signed_in_flight {
+ return Err(ChannelError::Close("closing_signed negotiation failed to finish within two timer ticks".to_owned()));
+ } else {
+ self.closing_signed_in_flight = true;
+ }
+ }
+ Ok(())
+ }
+
pub fn maybe_propose_closing_signed<F: Deref, L: Deref>(&mut self, fee_estimator: &F, logger: &L)
-> Result<(Option<msgs::ClosingSigned>, Option<Transaction>), ChannelError>
where F::Target: FeeEstimator, L::Target: Logger
{
- if !self.pending_inbound_htlcs.is_empty() || !self.pending_outbound_htlcs.is_empty() ||
- self.channel_state &
- (BOTH_SIDES_SHUTDOWN_MASK | ChannelState::AwaitingRemoteRevoke as u32 |
- ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateFailed as u32)
- != BOTH_SIDES_SHUTDOWN_MASK ||
- self.last_sent_closing_fee.is_some() || self.pending_update_fee.is_some() {
+ if self.last_sent_closing_fee.is_some() || !self.closing_negotiation_ready() {
return Ok((None, None));
}
Ok((shutdown, monitor_update, dropped_outbound_htlcs))
}
- fn build_signed_closing_transaction(&self, tx: &mut Transaction, counterparty_sig: &Signature, sig: &Signature) {
- if tx.input.len() != 1 { panic!("Tried to sign closing transaction that had input count != 1!"); }
- if tx.input[0].witness.len() != 0 { panic!("Tried to re-sign closing transaction"); }
- if tx.output.len() > 2 { panic!("Tried to sign bogus closing transaction"); }
+ fn build_signed_closing_transaction(&self, closing_tx: &ClosingTransaction, counterparty_sig: &Signature, sig: &Signature) -> Transaction {
+ let mut tx = closing_tx.trust().built_transaction().clone();
tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
tx.input[0].witness[2].push(SigHashType::All as u8);
tx.input[0].witness.push(self.get_funding_redeemscript().into_bytes());
+ tx
}
pub fn closing_signed<F: Deref>(&mut self, fee_estimator: &F, msg: &msgs::ClosingSigned) -> Result<(Option<msgs::ClosingSigned>, Option<Transaction>), ChannelError>
let funding_redeemscript = self.get_funding_redeemscript();
let (mut closing_tx, used_total_fee) = self.build_closing_transaction(msg.fee_satoshis, false);
if used_total_fee != msg.fee_satoshis {
- return Err(ChannelError::Close(format!("Remote sent us a closing_signed with a fee greater than the value they can claim. Fee in message: {}", msg.fee_satoshis)));
+ return Err(ChannelError::Close(format!("Remote sent us a closing_signed with a fee other than the value they can claim. Fee in message: {}. Actual closing tx fee: {}", msg.fee_satoshis, used_total_fee)));
}
- let mut sighash = hash_to_message!(&bip143::SigHashCache::new(&closing_tx).signature_hash(0, &funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]);
+ let sighash = closing_tx.trust().get_sighash_all(&funding_redeemscript, self.channel_value_satoshis);
match self.secp_ctx.verify(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
Ok(_) => {},
// The remote end may have decided to revoke their output due to inconsistent dust
// limits, so check for that case by re-checking the signature here.
closing_tx = self.build_closing_transaction(msg.fee_satoshis, true).0;
- sighash = hash_to_message!(&bip143::SigHashCache::new(&closing_tx).signature_hash(0, &funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]);
+ let sighash = closing_tx.trust().get_sighash_all(&funding_redeemscript, self.channel_value_satoshis);
secp_check!(self.secp_ctx.verify(&sighash, &msg.signature, self.counterparty_funding_pubkey()), "Invalid closing tx signature from peer".to_owned());
},
};
assert!(self.shutdown_scriptpubkey.is_some());
if let Some((last_fee, sig)) = self.last_sent_closing_fee {
if last_fee == msg.fee_satoshis {
- self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
+ let tx = self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
self.channel_state = ChannelState::ShutdownComplete as u32;
self.update_time_counter += 1;
- return Ok((None, Some(closing_tx)));
+ return Ok((None, Some(tx)));
}
}
macro_rules! propose_fee {
($new_fee: expr) => {
- let (mut tx, used_fee) = if $new_fee == msg.fee_satoshis {
+ let (closing_tx, used_fee) = if $new_fee == msg.fee_satoshis {
(closing_tx, $new_fee)
} else {
self.build_closing_transaction($new_fee, false)
};
let sig = self.holder_signer
- .sign_closing_transaction(&tx, &self.secp_ctx)
+ .sign_closing_transaction(&closing_tx, &self.secp_ctx)
.map_err(|_| ChannelError::Close("External signer refused to sign closing transaction".to_owned()))?;
let signed_tx = if $new_fee == msg.fee_satoshis {
self.channel_state = ChannelState::ShutdownComplete as u32;
self.update_time_counter += 1;
- self.build_signed_closing_transaction(&mut tx, &msg.signature, &sig);
+ let tx = self.build_signed_closing_transaction(&closing_tx, &msg.signature, &sig);
Some(tx)
} else { None };
// more dust balance if the feerate increases when we have several HTLCs pending
// which are near the dust limit.
let mut feerate_per_kw = self.feerate_per_kw;
+ // If there's a pending update fee, use it to ensure we aren't under-estimating
+ // potential feerate updates coming soon.
if let Some((feerate, _)) = self.pending_update_fee {
feerate_per_kw = cmp::max(feerate_per_kw, feerate);
}
if self.is_outbound() {
self.pending_update_fee.map(|(a, _)| a).write(writer)?;
} else if let Some((feerate, FeeUpdateState::AwaitingRemoteRevokeToAnnounce)) = self.pending_update_fee {
- // As for inbound HTLCs, if the update was only announced and never committed, drop it.
Some(feerate).write(writer)?;
} else {
+ // As for inbound HTLCs, if the update was only announced and never committed in a
+ // commitment_signed, drop it.
None::<u32>.write(writer)?;
}
self.holding_cell_update_fee.write(writer)?;
commitment_secrets,
channel_update_status,
+ closing_signed_in_flight: false,
announcement_sigs,
projects / rust-lightning / blobdiff