use bitcoin::blockdata::script::{Script,Builder};
use bitcoin::blockdata::transaction::{TxIn, TxOut, Transaction, SigHashType};
-use bitcoin::blockdata::opcodes;
use bitcoin::util::bip143;
use bitcoin::consensus::encode;
use bitcoin::hashes::Hash;
use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hashes::sha256d::Hash as Sha256d;
-use bitcoin::hash_types::{Txid, BlockHash, WPubkeyHash};
+use bitcoin::hash_types::{Txid, BlockHash};
+use bitcoin::secp256k1::constants::PUBLIC_KEY_SIZE;
use bitcoin::secp256k1::key::{PublicKey,SecretKey};
use bitcoin::secp256k1::{Secp256k1,Signature};
use bitcoin::secp256k1;
use ln::features::{ChannelFeatures, InitFeatures};
use ln::msgs;
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;
use io;
use prelude::*;
use core::{cmp,mem,fmt};
+use core::convert::TryFrom;
use core::ops::Deref;
#[cfg(any(test, feature = "fuzztarget", debug_assertions))]
use sync::Mutex;
use bitcoin::hashes::hex::ToHex;
-use bitcoin::blockdata::opcodes::all::OP_PUSHBYTES_0;
#[cfg(test)]
pub struct ChannelValueStat {
RemoteOffered,
}
+/// An enum gathering stats on pending HTLCs, either inbound or outbound side.
+struct HTLCStats {
+ pending_htlcs: u32,
+ pending_htlcs_value_msat: u64,
+ on_counterparty_tx_dust_exposure_msat: u64,
+ on_holder_tx_dust_exposure_msat: u64,
+}
+
/// Used when calculating whether we or the remote can afford an additional HTLC.
struct HTLCCandidate {
amount_msat: u64,
latest_monitor_update_id: u64,
holder_signer: Signer,
- shutdown_pubkey: PublicKey,
+ shutdown_scriptpubkey: Option<ShutdownScript>,
destination_script: Script,
// Our commitment numbers start at 2^48-1 and count down, whereas the ones used in transaction
}
// Constructors:
- pub fn new_outbound<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, channel_value_satoshis: u64, push_msat: u64, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, APIError>
+ pub fn new_outbound<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, their_features: &InitFeatures, channel_value_satoshis: u64, push_msat: u64, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, APIError>
where K::Target: KeysInterface<Signer = Signer>,
F::Target: FeeEstimator,
{
let mut secp_ctx = Secp256k1::new();
secp_ctx.seeded_randomize(&keys_provider.get_secure_random_bytes());
+ let shutdown_scriptpubkey = if config.channel_options.commit_upfront_shutdown_pubkey {
+ Some(keys_provider.get_shutdown_scriptpubkey())
+ } else { None };
+
+ if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
+ if !shutdown_scriptpubkey.is_compatible(&their_features) {
+ return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() });
+ }
+ }
+
Ok(Channel {
user_id,
config: config.channel_options.clone(),
latest_monitor_update_id: 0,
holder_signer,
- shutdown_pubkey: keys_provider.get_shutdown_pubkey(),
+ shutdown_scriptpubkey,
destination_script: keys_provider.get_destination_script(),
cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
/// Creates a new channel from a remote sides' request for one.
/// Assumes chain_hash has already been checked and corresponds with what we expect!
- pub fn new_from_req<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, ChannelError>
+ pub fn new_from_req<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, their_features: &InitFeatures, msg: &msgs::OpenChannel, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, ChannelError>
where K::Target: KeysInterface<Signer = Signer>,
F::Target: FeeEstimator
{
// Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
if script.len() == 0 {
None
- // Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. Fail the channel
- } else if is_unsupported_shutdown_script(&their_features, script) {
- return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex())));
} else {
- Some(script.clone())
+ match ShutdownScript::try_from((script.clone(), their_features)) {
+ Ok(shutdown_script) => Some(shutdown_script.into_inner()),
+ Err(_) => return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script))),
+ }
}
},
// Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
}
} else { None };
+ let shutdown_scriptpubkey = if config.channel_options.commit_upfront_shutdown_pubkey {
+ Some(keys_provider.get_shutdown_scriptpubkey())
+ } else { None };
+
+ if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
+ if !shutdown_scriptpubkey.is_compatible(&their_features) {
+ return Err(ChannelError::Close(format!("Provided a scriptpubkey format not accepted by peer: {}", shutdown_scriptpubkey)));
+ }
+ }
+
let mut secp_ctx = Secp256k1::new();
secp_ctx.seeded_randomize(&keys_provider.get_secure_random_bytes());
latest_monitor_update_id: 0,
holder_signer,
- shutdown_pubkey: keys_provider.get_shutdown_pubkey(),
+ shutdown_scriptpubkey,
destination_script: keys_provider.get_destination_script(),
cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
#[inline]
fn get_closing_scriptpubkey(&self) -> Script {
- let channel_close_key_hash = WPubkeyHash::hash(&self.shutdown_pubkey.serialize());
- Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&channel_close_key_hash[..]).into_script()
+ // The shutdown scriptpubkey is set on channel opening when option_upfront_shutdown_script
+ // is signaled. Otherwise, it is set when sending a shutdown message. Calling this method
+ // outside of those situations will fail.
+ self.shutdown_scriptpubkey.clone().unwrap().into_inner()
}
#[inline]
}, ()));
}
+ 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(),
// Message handlers:
- pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, config: &UserConfig, their_features: InitFeatures) -> Result<(), ChannelError> {
+ pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, config: &UserConfig, their_features: &InitFeatures) -> Result<(), ChannelError> {
// Check sanity of message fields:
if !self.is_outbound() {
return Err(ChannelError::Close("Got an accept_channel message from an inbound peer".to_owned()));
// Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
if script.len() == 0 {
None
- // Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. Fail the channel
- } else if is_unsupported_shutdown_script(&their_features, script) {
- return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex())));
} else {
- Some(script.clone())
+ match ShutdownScript::try_from((script.clone(), their_features)) {
+ Ok(shutdown_script) => Some(shutdown_script.into_inner()),
+ Err(_) => return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script))),
+ }
}
},
// Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
let funding_redeemscript = self.get_funding_redeemscript();
let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.is_outbound());
+ let shutdown_script = self.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
let channel_monitor = ChannelMonitor::new(self.secp_ctx.clone(), self.holder_signer.clone(),
- &self.shutdown_pubkey, self.get_holder_selected_contest_delay(),
+ shutdown_script, self.get_holder_selected_contest_delay(),
&self.destination_script, (funding_txo, funding_txo_script.clone()),
&self.channel_transaction_parameters,
funding_redeemscript.clone(), self.channel_value_satoshis,
let funding_txo = self.get_funding_txo().unwrap();
let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.is_outbound());
+ let shutdown_script = self.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
let channel_monitor = ChannelMonitor::new(self.secp_ctx.clone(), self.holder_signer.clone(),
- &self.shutdown_pubkey, self.get_holder_selected_contest_delay(),
+ shutdown_script, self.get_holder_selected_contest_delay(),
&self.destination_script, (funding_txo, funding_txo_script),
&self.channel_transaction_parameters,
funding_redeemscript.clone(), self.channel_value_satoshis,
Ok(())
}
- /// Returns (inbound_htlc_count, htlc_inbound_value_msat)
- fn get_inbound_pending_htlc_stats(&self) -> (u32, u64) {
- let mut htlc_inbound_value_msat = 0;
+ /// Returns a HTLCStats about inbound pending htlcs
+ fn get_inbound_pending_htlc_stats(&self) -> HTLCStats {
+ let mut stats = HTLCStats {
+ pending_htlcs: self.pending_inbound_htlcs.len() as u32,
+ pending_htlcs_value_msat: 0,
+ on_counterparty_tx_dust_exposure_msat: 0,
+ on_holder_tx_dust_exposure_msat: 0,
+ };
+
+ let counterparty_dust_limit_timeout_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+ let holder_dust_limit_success_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
for ref htlc in self.pending_inbound_htlcs.iter() {
- htlc_inbound_value_msat += htlc.amount_msat;
+ stats.pending_htlcs_value_msat += htlc.amount_msat;
+ if htlc.amount_msat / 1000 < counterparty_dust_limit_timeout_sat {
+ stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+ }
+ if htlc.amount_msat / 1000 < holder_dust_limit_success_sat {
+ stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+ }
}
- (self.pending_inbound_htlcs.len() as u32, htlc_inbound_value_msat)
+ stats
}
- /// Returns (outbound_htlc_count, htlc_outbound_value_msat) *including* pending adds in our
- /// holding cell.
- fn get_outbound_pending_htlc_stats(&self) -> (u32, u64) {
- let mut htlc_outbound_value_msat = 0;
+ /// Returns a HTLCStats about pending outbound htlcs, *including* pending adds in our holding cell.
+ fn get_outbound_pending_htlc_stats(&self) -> HTLCStats {
+ let mut stats = HTLCStats {
+ pending_htlcs: self.pending_outbound_htlcs.len() as u32,
+ pending_htlcs_value_msat: 0,
+ on_counterparty_tx_dust_exposure_msat: 0,
+ on_holder_tx_dust_exposure_msat: 0,
+ };
+
+ let counterparty_dust_limit_success_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+ let holder_dust_limit_timeout_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
for ref htlc in self.pending_outbound_htlcs.iter() {
- htlc_outbound_value_msat += htlc.amount_msat;
+ stats.pending_htlcs_value_msat += htlc.amount_msat;
+ if htlc.amount_msat / 1000 < counterparty_dust_limit_success_sat {
+ stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+ }
+ if htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat {
+ stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+ }
}
- let mut htlc_outbound_count = self.pending_outbound_htlcs.len();
for update in self.holding_cell_htlc_updates.iter() {
if let &HTLCUpdateAwaitingACK::AddHTLC { ref amount_msat, .. } = update {
- htlc_outbound_count += 1;
- htlc_outbound_value_msat += amount_msat;
+ stats.pending_htlcs += 1;
+ stats.pending_htlcs_value_msat += amount_msat;
+ if *amount_msat / 1000 < counterparty_dust_limit_success_sat {
+ stats.on_counterparty_tx_dust_exposure_msat += amount_msat;
+ }
+ if *amount_msat / 1000 < holder_dust_limit_timeout_sat {
+ stats.on_holder_tx_dust_exposure_msat += amount_msat;
+ }
}
}
-
- (htlc_outbound_count as u32, htlc_outbound_value_msat)
+ stats
}
/// Get the available (ie not including pending HTLCs) inbound and outbound balance in msat.
(
cmp::max(self.channel_value_satoshis as i64 * 1000
- self.value_to_self_msat as i64
- - self.get_inbound_pending_htlc_stats().1 as i64
+ - self.get_inbound_pending_htlc_stats().pending_htlcs_value_msat as i64
- Self::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) as i64 * 1000,
0) as u64,
cmp::max(self.value_to_self_msat as i64
- - self.get_outbound_pending_htlc_stats().1 as i64
+ - self.get_outbound_pending_htlc_stats().pending_htlcs_value_msat as i64
- self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) as i64 * 1000,
0) as u64
)
return Err(ChannelError::Close(format!("Remote side tried to send less than our minimum HTLC value. Lower limit: ({}). Actual: ({})", self.holder_htlc_minimum_msat, msg.amount_msat)));
}
- let (inbound_htlc_count, htlc_inbound_value_msat) = self.get_inbound_pending_htlc_stats();
- if inbound_htlc_count + 1 > OUR_MAX_HTLCS as u32 {
+ let inbound_stats = self.get_inbound_pending_htlc_stats();
+ let outbound_stats = self.get_outbound_pending_htlc_stats();
+ if inbound_stats.pending_htlcs + 1 > OUR_MAX_HTLCS as u32 {
return Err(ChannelError::Close(format!("Remote tried to push more than our max accepted HTLCs ({})", OUR_MAX_HTLCS)));
}
let holder_max_htlc_value_in_flight_msat = Channel::<Signer>::get_holder_max_htlc_value_in_flight_msat(self.channel_value_satoshis);
- if htlc_inbound_value_msat + msg.amount_msat > holder_max_htlc_value_in_flight_msat {
+ if inbound_stats.pending_htlcs_value_msat + msg.amount_msat > holder_max_htlc_value_in_flight_msat {
return Err(ChannelError::Close(format!("Remote HTLC add would put them over our max HTLC value ({})", holder_max_htlc_value_in_flight_msat)));
}
// Check holder_selected_channel_reserve_satoshis (we're getting paid, so they have to at least meet
}
}
+ 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 + htlc_inbound_value_msat - removed_outbound_total_msat;
+ self.value_to_self_msat + inbound_stats.pending_htlcs_value_msat - removed_outbound_total_msat;
let pending_remote_value_msat =
self.channel_value_satoshis * 1000 - pending_value_to_self_msat;
if pending_remote_value_msat < msg.amount_msat {
self.channel_state &= !(ChannelState::PeerDisconnected as u32);
let shutdown_msg = if self.channel_state & (ChannelState::LocalShutdownSent as u32) != 0 {
+ assert!(self.shutdown_scriptpubkey.is_some());
Some(msgs::Shutdown {
channel_id: self.channel_id,
scriptpubkey: self.get_closing_scriptpubkey(),
if self.feerate_per_kw > proposed_feerate {
proposed_feerate = self.feerate_per_kw;
}
+ assert!(self.shutdown_scriptpubkey.is_some());
let tx_weight = self.get_closing_transaction_weight(Some(&self.get_closing_scriptpubkey()), Some(self.counterparty_shutdown_scriptpubkey.as_ref().unwrap()));
let proposed_total_fee_satoshis = proposed_feerate as u64 * tx_weight / 1000;
})
}
- pub fn shutdown<F: Deref>(&mut self, fee_estimator: &F, their_features: &InitFeatures, msg: &msgs::Shutdown) -> Result<(Option<msgs::Shutdown>, Option<msgs::ClosingSigned>, Vec<(HTLCSource, PaymentHash)>), ChannelError>
- where F::Target: FeeEstimator
+ pub fn shutdown<F: Deref, K: Deref>(
+ &mut self, fee_estimator: &F, keys_provider: &K, their_features: &InitFeatures, msg: &msgs::Shutdown
+ ) -> Result<(Option<msgs::Shutdown>, Option<msgs::ClosingSigned>, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>), ChannelError>
+ where
+ F::Target: FeeEstimator,
+ K::Target: KeysInterface<Signer = Signer>
{
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(ChannelError::Close("Peer sent shutdown when we needed a channel_reestablish".to_owned()));
}
assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0);
- if is_unsupported_shutdown_script(&their_features, &msg.scriptpubkey) {
- return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex())));
- }
+ let shutdown_scriptpubkey = match ShutdownScript::try_from((msg.scriptpubkey.clone(), their_features)) {
+ Ok(script) => script.into_inner(),
+ Err(_) => return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex()))),
+ };
if self.counterparty_shutdown_scriptpubkey.is_some() {
- if Some(&msg.scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() {
- return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", msg.scriptpubkey.to_bytes().to_hex())));
+ if Some(&shutdown_scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() {
+ return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", shutdown_scriptpubkey.to_bytes().to_hex())));
}
} else {
- self.counterparty_shutdown_scriptpubkey = Some(msg.scriptpubkey.clone());
+ self.counterparty_shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
}
+ // If we have any LocalAnnounced updates we'll probably just get back an update_fail_htlc
+ // immediately after the commitment dance, but we can send a Shutdown because we won't send
+ // any further commitment updates after we set LocalShutdownSent.
+ let send_shutdown = (self.channel_state & ChannelState::LocalShutdownSent as u32) != ChannelState::LocalShutdownSent as u32;
+
+ let update_shutdown_script = match self.shutdown_scriptpubkey {
+ Some(_) => false,
+ None => {
+ assert!(send_shutdown);
+ let shutdown_scriptpubkey = keys_provider.get_shutdown_scriptpubkey();
+ if !shutdown_scriptpubkey.is_compatible(their_features) {
+ return Err(ChannelError::Close(format!("Provided a scriptpubkey format not accepted by peer: {}", shutdown_scriptpubkey)));
+ }
+ self.shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
+ true
+ },
+ };
+
// From here on out, we may not fail!
self.channel_state |= ChannelState::RemoteShutdownSent as u32;
self.update_time_counter += 1;
+ let monitor_update = if update_shutdown_script {
+ self.latest_monitor_update_id += 1;
+ Some(ChannelMonitorUpdate {
+ update_id: self.latest_monitor_update_id,
+ updates: vec![ChannelMonitorUpdateStep::ShutdownScript {
+ scriptpubkey: self.get_closing_scriptpubkey(),
+ }],
+ })
+ } else { None };
+ let shutdown = if send_shutdown {
+ Some(msgs::Shutdown {
+ channel_id: self.channel_id,
+ scriptpubkey: self.get_closing_scriptpubkey(),
+ })
+ } else { None };
+
// We can't send our shutdown until we've committed all of our pending HTLCs, but the
// remote side is unlikely to accept any new HTLCs, so we go ahead and "free" any holding
// cell HTLCs and return them to fail the payment.
_ => true
}
});
- // If we have any LocalAnnounced updates we'll probably just get back a update_fail_htlc
- // immediately after the commitment dance, but we can send a Shutdown cause we won't send
- // any further commitment updates after we set LocalShutdownSent.
-
- let shutdown = if (self.channel_state & ChannelState::LocalShutdownSent as u32) == ChannelState::LocalShutdownSent as u32 {
- None
- } else {
- Some(msgs::Shutdown {
- channel_id: self.channel_id,
- scriptpubkey: self.get_closing_scriptpubkey(),
- })
- };
self.channel_state |= ChannelState::LocalShutdownSent as u32;
self.update_time_counter += 1;
- Ok((shutdown, self.maybe_propose_first_closing_signed(fee_estimator), dropped_outbound_htlcs))
+ Ok((shutdown, self.maybe_propose_first_closing_signed(fee_estimator), monitor_update, dropped_outbound_htlcs))
}
fn build_signed_closing_transaction(&self, tx: &mut Transaction, counterparty_sig: &Signature, sig: &Signature) {
macro_rules! propose_new_feerate {
($new_feerate: expr) => {
+ assert!(self.shutdown_scriptpubkey.is_some());
let tx_weight = self.get_closing_transaction_weight(Some(&self.get_closing_scriptpubkey()), Some(self.counterparty_shutdown_scriptpubkey.as_ref().unwrap()));
let (closing_tx, used_total_fee) = self.build_closing_transaction($new_feerate as u64 * tx_weight / 1000, false);
let sig = self.holder_signer
cmp::max(self.config.cltv_expiry_delta, MIN_CLTV_EXPIRY_DELTA)
}
+ pub fn get_max_dust_htlc_exposure_msat(&self) -> u64 {
+ self.config.max_dust_htlc_exposure_msat
+ }
+
#[cfg(test)]
pub fn get_feerate(&self) -> u32 {
self.feerate_per_kw
}
+ pub fn get_dust_buffer_feerate(&self) -> u32 {
+ // When calculating our exposure to dust HTLCs, we assume that the channel feerate
+ // may, at any point, increase by at least 10 sat/vB (i.e 2530 sat/kWU) or 25%,
+ // whichever is higher. This ensures that we aren't suddenly exposed to significantly
+ // more dust balance if the feerate increases when we have several HTLCs pending
+ // which are near the dust limit.
+ cmp::max(2530, self.feerate_per_kw * 1250 / 1000)
+ }
+
pub fn get_cur_holder_commitment_transaction_number(&self) -> u64 {
self.cur_holder_commitment_transaction_number + 1
}
htlc_basepoint: keys.htlc_basepoint,
first_per_commitment_point,
channel_flags: if self.config.announced_channel {1} else {0},
- shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() })
+ shutdown_scriptpubkey: OptionalField::Present(match &self.shutdown_scriptpubkey {
+ Some(script) => script.clone().into_inner(),
+ None => Builder::new().into_script(),
+ }),
}
}
delayed_payment_basepoint: keys.delayed_payment_basepoint,
htlc_basepoint: keys.htlc_basepoint,
first_per_commitment_point,
- shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() })
+ shutdown_scriptpubkey: OptionalField::Present(match &self.shutdown_scriptpubkey {
+ Some(script) => script.clone().into_inner(),
+ None => Builder::new().into_script(),
+ }),
}
}
return Err(ChannelError::Ignore("Cannot send an HTLC while disconnected from channel counterparty".to_owned()));
}
- let (outbound_htlc_count, htlc_outbound_value_msat) = self.get_outbound_pending_htlc_stats();
- if outbound_htlc_count + 1 > self.counterparty_max_accepted_htlcs as u32 {
+ let inbound_stats = self.get_inbound_pending_htlc_stats();
+ let outbound_stats = self.get_outbound_pending_htlc_stats();
+ if outbound_stats.pending_htlcs + 1 > self.counterparty_max_accepted_htlcs as u32 {
return Err(ChannelError::Ignore(format!("Cannot push more than their max accepted HTLCs ({})", self.counterparty_max_accepted_htlcs)));
}
// Check their_max_htlc_value_in_flight_msat
- if htlc_outbound_value_msat + amount_msat > self.counterparty_max_htlc_value_in_flight_msat {
+ if outbound_stats.pending_htlcs_value_msat + amount_msat > self.counterparty_max_htlc_value_in_flight_msat {
return Err(ChannelError::Ignore(format!("Cannot send value that would put us over the max HTLC value in flight our peer will accept ({})", self.counterparty_max_htlc_value_in_flight_msat)));
}
}
}
- let pending_value_to_self_msat = self.value_to_self_msat - htlc_outbound_value_msat;
+ 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)));
}
/// Begins the shutdown process, getting a message for the remote peer and returning all
/// holding cell HTLCs for payment failure.
- pub fn get_shutdown(&mut self) -> Result<(msgs::Shutdown, Vec<(HTLCSource, PaymentHash)>), APIError> {
+ pub fn get_shutdown<K: Deref>(&mut self, keys_provider: &K, their_features: &InitFeatures) -> Result<(msgs::Shutdown, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>), APIError>
+ where K::Target: KeysInterface<Signer = Signer> {
for htlc in self.pending_outbound_htlcs.iter() {
if let OutboundHTLCState::LocalAnnounced(_) = htlc.state {
return Err(APIError::APIMisuseError{err: "Cannot begin shutdown with pending HTLCs. Process pending events first".to_owned()});
return Err(APIError::ChannelUnavailable{err: "Cannot begin shutdown while peer is disconnected or we're waiting on a monitor update, maybe force-close instead?".to_owned()});
}
- let closing_script = self.get_closing_scriptpubkey();
+ let update_shutdown_script = match self.shutdown_scriptpubkey {
+ Some(_) => false,
+ None => {
+ let shutdown_scriptpubkey = keys_provider.get_shutdown_scriptpubkey();
+ if !shutdown_scriptpubkey.is_compatible(their_features) {
+ return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() });
+ }
+ self.shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
+ true
+ },
+ };
// From here on out, we may not fail!
if self.channel_state < ChannelState::FundingSent as u32 {
}
self.update_time_counter += 1;
+ let monitor_update = if update_shutdown_script {
+ self.latest_monitor_update_id += 1;
+ Some(ChannelMonitorUpdate {
+ update_id: self.latest_monitor_update_id,
+ updates: vec![ChannelMonitorUpdateStep::ShutdownScript {
+ scriptpubkey: self.get_closing_scriptpubkey(),
+ }],
+ })
+ } else { None };
+ let shutdown = msgs::Shutdown {
+ channel_id: self.channel_id,
+ scriptpubkey: self.get_closing_scriptpubkey(),
+ };
+
// Go ahead and drop holding cell updates as we'd rather fail payments than wait to send
// our shutdown until we've committed all of the pending changes.
self.holding_cell_update_fee = None;
}
});
- Ok((msgs::Shutdown {
- channel_id: self.channel_id,
- scriptpubkey: closing_script,
- }, dropped_outbound_htlcs))
+ Ok((shutdown, monitor_update, dropped_outbound_htlcs))
}
/// Gets the latest commitment transaction and any dependent transactions for relay (forcing
}
}
-fn is_unsupported_shutdown_script(their_features: &InitFeatures, script: &Script) -> bool {
- // We restrain shutdown scripts to standards forms to avoid transactions not propagating on the p2p tx-relay network
-
- // BOLT 2 says we must only send a scriptpubkey of certain standard forms,
- // which for a a BIP-141-compliant witness program is at max 42 bytes in length.
- // So don't let the remote peer feed us some super fee-heavy script.
- let is_script_too_long = script.len() > 42;
- if is_script_too_long {
- return true;
- }
-
- if their_features.supports_shutdown_anysegwit() && script.is_witness_program() && script.as_bytes()[0] != OP_PUSHBYTES_0.into_u8() {
- return false;
- }
-
- return !script.is_p2pkh() && !script.is_p2sh() && !script.is_v0_p2wpkh() && !script.is_v0_p2wsh()
-}
-
const SERIALIZATION_VERSION: u8 = 2;
const MIN_SERIALIZATION_VERSION: u8 = 1;
(key_data.0.len() as u32).write(writer)?;
writer.write_all(&key_data.0[..])?;
- self.shutdown_pubkey.write(writer)?;
+ // Write out the old serialization for shutdown_pubkey for backwards compatibility, if
+ // deserialized from that format.
+ match self.shutdown_scriptpubkey.as_ref().and_then(|script| script.as_legacy_pubkey()) {
+ Some(shutdown_pubkey) => shutdown_pubkey.write(writer)?,
+ None => [0u8; PUBLIC_KEY_SIZE].write(writer)?,
+ }
self.destination_script.write(writer)?;
self.cur_holder_commitment_transaction_number.write(writer)?;
(1, self.minimum_depth, option),
(3, self.counterparty_selected_channel_reserve_satoshis, option),
(5, self.config, required),
+ (7, self.shutdown_scriptpubkey, option),
});
Ok(())
}
let holder_signer = keys_source.read_chan_signer(&keys_data)?;
- let shutdown_pubkey = Readable::read(reader)?;
+ // Read the old serialization for shutdown_pubkey, preferring the TLV field later if set.
+ let mut shutdown_scriptpubkey = match <PublicKey as Readable>::read(reader) {
+ Ok(pubkey) => Some(ShutdownScript::new_p2wpkh_from_pubkey(pubkey)),
+ Err(_) => None,
+ };
let destination_script = Readable::read(reader)?;
let cur_holder_commitment_transaction_number = Readable::read(reader)?;
(1, minimum_depth, option),
(3, counterparty_selected_channel_reserve_satoshis, option),
(5, config, option), // Note that if none is provided we will *not* overwrite the existing one.
+ (7, shutdown_scriptpubkey, option),
});
let mut secp_ctx = Secp256k1::new();
latest_monitor_update_id,
holder_signer,
- shutdown_pubkey,
+ shutdown_scriptpubkey,
destination_script,
cur_holder_commitment_transaction_number,
use ln::channel::MAX_FUNDING_SATOSHIS;
use ln::features::InitFeatures;
use ln::msgs::{ChannelUpdate, DataLossProtect, DecodeError, OptionalField, UnsignedChannelUpdate};
+ use ln::script::ShutdownScript;
use ln::chan_utils;
use ln::chan_utils::{ChannelPublicKeys, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT};
use chain::BestBlock;
use chain::transaction::OutPoint;
use util::config::UserConfig;
use util::enforcing_trait_impls::EnforcingSigner;
+ use util::errors::APIError;
use util::test_utils;
+ use util::test_utils::OnGetShutdownScriptpubkey;
use util::logger::Logger;
use bitcoin::secp256k1::{Secp256k1, Message, Signature, All};
use bitcoin::secp256k1::ffi::Signature as FFISignature;
use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hashes::Hash;
use bitcoin::hash_types::{Txid, WPubkeyHash};
+ use core::num::NonZeroU8;
use sync::Arc;
use prelude::*;
Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&channel_monitor_claim_key_hash[..]).into_script()
}
- fn get_shutdown_pubkey(&self) -> PublicKey {
+ fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
let secp_ctx = Secp256k1::signing_only();
let channel_close_key = SecretKey::from_slice(&hex::decode("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap();
- PublicKey::from_secret_key(&secp_ctx, &channel_close_key)
+ ShutdownScript::new_p2wpkh_from_pubkey(PublicKey::from_secret_key(&secp_ctx, &channel_close_key))
}
fn get_channel_signer(&self, _inbound: bool, _channel_value_satoshis: u64) -> InMemorySigner {
PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode(hex).unwrap()[..]).unwrap())
}
+ #[test]
+ fn upfront_shutdown_script_incompatibility() {
+ let features = InitFeatures::known().clear_shutdown_anysegwit();
+ let non_v0_segwit_shutdown_script =
+ ShutdownScript::new_witness_program(NonZeroU8::new(16).unwrap(), &[0, 40]).unwrap();
+
+ let seed = [42; 32];
+ let network = Network::Testnet;
+ let keys_provider = test_utils::TestKeysInterface::new(&seed, network);
+ keys_provider.expect(OnGetShutdownScriptpubkey {
+ returns: non_v0_segwit_shutdown_script.clone(),
+ });
+
+ let fee_estimator = TestFeeEstimator { fee_est: 253 };
+ let secp_ctx = Secp256k1::new();
+ let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+ let config = UserConfig::default();
+ match Channel::<EnforcingSigner>::new_outbound(&&fee_estimator, &&keys_provider, node_id, &features, 10000000, 100000, 42, &config) {
+ Err(APIError::IncompatibleShutdownScript { script }) => {
+ assert_eq!(script.into_inner(), non_v0_segwit_shutdown_script.into_inner());
+ },
+ Err(e) => panic!("Unexpected error: {:?}", e),
+ Ok(_) => panic!("Expected error"),
+ }
+ }
+
// Check that, during channel creation, we use the same feerate in the open channel message
// as we do in the Channel object creation itself.
#[test]
let node_a_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
let config = UserConfig::default();
- let node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_a_node_id, 10000000, 100000, 42, &config).unwrap();
+ let node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_a_node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
// Now change the fee so we can check that the fee in the open_channel message is the
// same as the old fee.
// Create Node A's channel pointing to Node B's pubkey
let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
let config = UserConfig::default();
- let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
+ let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
// Create Node B's channel by receiving Node A's open_channel message
// Make sure A's dust limit is as we expect.
let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.block_hash());
let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap());
- let node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
+ let node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
// Node B --> Node A: accept channel, explicitly setting B's dust limit.
let mut accept_channel_msg = node_b_chan.get_accept_channel();
accept_channel_msg.dust_limit_satoshis = 546;
- node_a_chan.accept_channel(&accept_channel_msg, &config, InitFeatures::known()).unwrap();
+ node_a_chan.accept_channel(&accept_channel_msg, &config, &InitFeatures::known()).unwrap();
node_a_chan.holder_dust_limit_satoshis = 1560;
// Put some inbound and outbound HTLCs in A's channel.
let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
let config = UserConfig::default();
- let mut chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_id, 10000000, 100000, 42, &config).unwrap();
+ let mut chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
let commitment_tx_fee_0_htlcs = chan.commit_tx_fee_msat(0);
let commitment_tx_fee_1_htlc = chan.commit_tx_fee_msat(1);
// Create Node A's channel pointing to Node B's pubkey
let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
let config = UserConfig::default();
- let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
+ let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
// Create Node B's channel by receiving Node A's open_channel message
let open_channel_msg = node_a_chan.get_open_channel(chain_hash);
let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap());
- let mut node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
+ let mut node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
// Node B --> Node A: accept channel
let accept_channel_msg = node_b_chan.get_accept_channel();
- node_a_chan.accept_channel(&accept_channel_msg, &config, InitFeatures::known()).unwrap();
+ node_a_chan.accept_channel(&accept_channel_msg, &config, &InitFeatures::known()).unwrap();
// Node A --> Node B: funding created
let output_script = node_a_chan.get_funding_redeemscript();
// Create a channel.
let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
let config = UserConfig::default();
- let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
+ let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
assert!(node_a_chan.counterparty_forwarding_info.is_none());
assert_eq!(node_a_chan.holder_htlc_minimum_msat, 1); // the default
assert!(node_a_chan.counterparty_forwarding_info().is_none());
let counterparty_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
let mut config = UserConfig::default();
config.channel_options.announced_channel = false;
- let mut chan = Channel::<InMemorySigner>::new_outbound(&&feeest, &&keys_provider, counterparty_node_id, 10_000_000, 100000, 42, &config).unwrap(); // Nothing uses their network key in this test
+ let mut chan = Channel::<InMemorySigner>::new_outbound(&&feeest, &&keys_provider, counterparty_node_id, &InitFeatures::known(), 10_000_000, 100000, 42, &config).unwrap(); // Nothing uses their network key in this test
chan.holder_dust_limit_satoshis = 546;
chan.counterparty_selected_channel_reserve_satoshis = Some(0); // Filled in in accept_channel