_ Git - rust-lightning/blob - lightning/src/util/test_channel_signer.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 use crate::ln::channel::{ANCHOR_OUTPUT_VALUE_SATOSHI, MIN_CHAN_DUST_LIMIT_SATOSHIS};
  11 use crate::ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction, ClosingTransaction};
  12 use crate::ln::channel_keys::{HtlcKey};
  13 use crate::ln::msgs;
  14 use crate::ln::types::PaymentPreimage;
  15 use crate::sign::{InMemorySigner, ChannelSigner};
  16 use crate::sign::ecdsa::EcdsaChannelSigner;
  17
  18 #[allow(unused_imports)]
  19 use crate::prelude::*;
  20
  21 use core::{cmp, fmt};
  22 use crate::sync::{Mutex, Arc};
  23 #[cfg(test)] use crate::sync::MutexGuard;
  24
  25 use bitcoin::blockdata::transaction::Transaction;
  26 use bitcoin::hashes::Hash;
  27 use bitcoin::sighash;
  28 use bitcoin::sighash::EcdsaSighashType;
  29
  30 use bitcoin::secp256k1;
  31 #[cfg(taproot)]
  32 use bitcoin::secp256k1::All;
  33 use bitcoin::secp256k1::{SecretKey, PublicKey};
  34 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
  35 #[cfg(taproot)]
  36 use musig2::types::{PartialSignature, PublicNonce, SecretNonce};
  37 use crate::sign::HTLCDescriptor;
  38 use crate::util::ser::{Writeable, Writer};
  39 use crate::io::Error;
  40 use crate::ln::features::ChannelTypeFeatures;
  41 #[cfg(taproot)]
  42 use crate::ln::msgs::PartialSignatureWithNonce;
  43 #[cfg(taproot)]
  44 use crate::sign::taproot::TaprootChannelSigner;
  45
  46 /// Initial value for revoked commitment downward counter
  47 pub const INITIAL_REVOKED_COMMITMENT_NUMBER: u64 = 1 << 48;
  48
  49 /// An implementation of Sign that enforces some policy checks.  The current checks
  50 /// are an incomplete set.  They include:
  51 ///
  52 /// - When signing, the holder transaction has not been revoked
  53 /// - When revoking, the holder transaction has not been signed
  54 /// - The holder commitment number is monotonic and without gaps
  55 /// - The revoked holder commitment number is monotonic and without gaps
  56 /// - There is at least one unrevoked holder transaction at all times
  57 /// - The counterparty commitment number is monotonic and without gaps
  58 /// - The pre-derived keys and pre-built transaction in CommitmentTransaction were correctly built
  59 ///
  60 /// Eventually we will probably want to expose a variant of this which would essentially
  61 /// be what you'd want to run on a hardware wallet.
  62 ///
  63 /// Note that counterparty signatures on the holder transaction are not checked, but it should
  64 /// be in a complete implementation.
  65 ///
  66 /// Note that before we do so we should ensure its serialization format has backwards- and
  67 /// forwards-compatibility prefix/suffixes!
  68 #[derive(Clone)]
  69 pub struct TestChannelSigner {
  70         pub inner: InMemorySigner,
  71         /// Channel state used for policy enforcement
  72         pub state: Arc<Mutex<EnforcementState>>,
  73         pub disable_revocation_policy_check: bool,
  74         /// When `true` (the default), the signer will respond immediately with signatures. When `false`,
  75         /// the signer will return an error indicating that it is unavailable.
  76         pub available: Arc<Mutex<bool>>,
  77         /// Set of signer operations that are disabled. If an operation is disabled,
  78         /// the signer will return `Err` when the corresponding method is called.
  79         pub disabled_signer_ops: Arc<Mutex<HashSet<SignerOp>>>,
  80 }
  81
  82 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
  83 pub enum SignerOp {
  84         GetPerCommitmentPoint,
  85         ReleaseCommitmentSecret,
  86         ValidateHolderCommitment,
  87         SignCounterpartyCommitment,
  88         ValidateCounterpartyRevocation,
  89         SignHolderCommitment,
  90         SignJusticeRevokedOutput,
  91         SignJusticeRevokedHtlc,
  92         SignHolderHtlcTransaction,
  93         SignCounterpartyHtlcTransaction,
  94         SignClosingTransaction,
  95         SignHolderAnchorInput,
  96         SignChannelAnnouncementWithFundingKey,
  97 }
  98
  99 impl fmt::Display for SignerOp {
 100         fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 101                 match self {
 102                         SignerOp::GetPerCommitmentPoint => write!(f, "get_per_commitment_point"),
 103                         SignerOp::ReleaseCommitmentSecret => write!(f, "release_commitment_secret"),
 104                         SignerOp::ValidateHolderCommitment => write!(f, "validate_holder_commitment"),
 105                         SignerOp::SignCounterpartyCommitment => write!(f, "sign_counterparty_commitment"),
 106                         SignerOp::ValidateCounterpartyRevocation => write!(f, "validate_counterparty_revocation"),
 107                         SignerOp::SignHolderCommitment => write!(f, "sign_holder_commitment"),
 108                         SignerOp::SignJusticeRevokedOutput => write!(f, "sign_justice_revoked_output"),
 109                         SignerOp::SignJusticeRevokedHtlc => write!(f, "sign_justice_revoked_htlc"),
 110                         SignerOp::SignHolderHtlcTransaction => write!(f, "sign_holder_htlc_transaction"),
 111                         SignerOp::SignCounterpartyHtlcTransaction => write!(f, "sign_counterparty_htlc_transaction"),
 112                         SignerOp::SignClosingTransaction => write!(f, "sign_closing_transaction"),
 113                         SignerOp::SignHolderAnchorInput => write!(f, "sign_holder_anchor_input"),
 114                         SignerOp::SignChannelAnnouncementWithFundingKey => write!(f, "sign_channel_announcement_with_funding_key"),
 115                 }
 116         }
 117 }
 118
 119 impl PartialEq for TestChannelSigner {
 120         fn eq(&self, o: &Self) -> bool {
 121                 Arc::ptr_eq(&self.state, &o.state)
 122         }
 123 }
 124
 125 impl TestChannelSigner {
 126         /// Construct an TestChannelSigner
 127         pub fn new(inner: InMemorySigner) -> Self {
 128                 let state = Arc::new(Mutex::new(EnforcementState::new()));
 129                 Self {
 130                         inner,
 131                         state,
 132                         disable_revocation_policy_check: false,
 133                         available: Arc::new(Mutex::new(true)),
 134                         disabled_signer_ops: Arc::new(Mutex::new(new_hash_set())),
 135                 }
 136         }
 137
 138         /// Construct an TestChannelSigner with externally managed storage
 139         ///
 140         /// Since there are multiple copies of this struct for each channel, some coordination is needed
 141         /// so that all copies are aware of enforcement state.  A pointer to this state is provided
 142         /// here, usually by an implementation of KeysInterface.
 143         pub fn new_with_revoked(inner: InMemorySigner, state: Arc<Mutex<EnforcementState>>, disable_revocation_policy_check: bool) -> Self {
 144                 Self {
 145                         inner,
 146                         state,
 147                         disable_revocation_policy_check,
 148                         available: Arc::new(Mutex::new(true)),
 149                         disabled_signer_ops: Arc::new(Mutex::new(new_hash_set())),
 150                 }
 151         }
 152
 153         pub fn channel_type_features(&self) -> &ChannelTypeFeatures { self.inner.channel_type_features().unwrap() }
 154
 155         #[cfg(test)]
 156         pub fn get_enforcement_state(&self) -> MutexGuard<EnforcementState> {
 157                 self.state.lock().unwrap()
 158         }
 159
 160         /// Marks the signer's availability.
 161         ///
 162         /// When `true`, methods are forwarded to the underlying signer as normal. When `false`, some
 163         /// methods will return `Err` indicating that the signer is unavailable. Intended to be used for
 164         /// testing asynchronous signing.
 165         pub fn set_available(&self, available: bool) {
 166                 *self.available.lock().unwrap() = available;
 167         }
 168
 169         pub fn enable_op(&mut self, signer_op: SignerOp) {
 170                 self.disabled_signer_ops.lock().unwrap().remove(&signer_op);
 171         }
 172
 173         pub fn disable_op(&mut self, signer_op: SignerOp) {
 174                 self.disabled_signer_ops.lock().unwrap().insert(signer_op);
 175         }
 176
 177         fn is_signer_available(&self, signer_op: SignerOp) -> bool {
 178                 !self.disabled_signer_ops.lock().unwrap().contains(&signer_op)
 179         }
 180 }
 181
 182 impl ChannelSigner for TestChannelSigner {
 183         fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
 184                 self.inner.get_per_commitment_point(idx, secp_ctx)
 185         }
 186
 187         fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
 188                 {
 189                         let mut state = self.state.lock().unwrap();
 190                         assert!(idx == state.last_holder_revoked_commitment || idx == state.last_holder_revoked_commitment - 1, "can only revoke the current or next unrevoked commitment - trying {}, last revoked {}", idx, state.last_holder_revoked_commitment);
 191                         assert!(idx > state.last_holder_commitment, "cannot revoke the last holder commitment - attempted to revoke {} last commitment {}", idx, state.last_holder_commitment);
 192                         state.last_holder_revoked_commitment = idx;
 193                 }
 194                 self.inner.release_commitment_secret(idx)
 195         }
 196
 197         fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction, _outbound_htlc_preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
 198                 let mut state = self.state.lock().unwrap();
 199                 let idx = holder_tx.commitment_number();
 200                 assert!(idx == state.last_holder_commitment || idx == state.last_holder_commitment - 1, "expecting to validate the current or next holder commitment - trying {}, current {}", idx, state.last_holder_commitment);
 201                 state.last_holder_commitment = idx;
 202                 Ok(())
 203         }
 204
 205         fn validate_counterparty_revocation(&self, idx: u64, _secret: &SecretKey) -> Result<(), ()> {
 206                 if !*self.available.lock().unwrap() {
 207                         return Err(());
 208                 }
 209                 let mut state = self.state.lock().unwrap();
 210                 assert!(idx == state.last_counterparty_revoked_commitment || idx == state.last_counterparty_revoked_commitment - 1, "expecting to validate the current or next counterparty revocation - trying {}, current {}", idx, state.last_counterparty_revoked_commitment);
 211                 state.last_counterparty_revoked_commitment = idx;
 212                 Ok(())
 213         }
 214
 215         fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
 216
 217         fn channel_keys_id(&self) -> [u8; 32] { self.inner.channel_keys_id() }
 218
 219         fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
 220                 self.inner.provide_channel_parameters(channel_parameters)
 221         }
 222 }
 223
 224 impl EcdsaChannelSigner for TestChannelSigner {
 225         fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, inbound_htlc_preimages: Vec<PaymentPreimage>, outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
 226                 self.verify_counterparty_commitment_tx(commitment_tx, secp_ctx);
 227
 228                 {
 229                         if !*self.available.lock().unwrap() {
 230                                 return Err(());
 231                         }
 232                         let mut state = self.state.lock().unwrap();
 233                         let actual_commitment_number = commitment_tx.commitment_number();
 234                         let last_commitment_number = state.last_counterparty_commitment;
 235                         // These commitment numbers are backwards counting.  We expect either the same as the previously encountered,
 236                         // or the next one.
 237                         assert!(last_commitment_number == actual_commitment_number || last_commitment_number - 1 == actual_commitment_number, "{} doesn't come after {}", actual_commitment_number, last_commitment_number);
 238                         // Ensure that the counterparty doesn't get more than two broadcastable commitments -
 239                         // the last and the one we are trying to sign
 240                         assert!(actual_commitment_number >= state.last_counterparty_revoked_commitment - 2, "cannot sign a commitment if second to last wasn't revoked - signing {} revoked {}", actual_commitment_number, state.last_counterparty_revoked_commitment);
 241                         state.last_counterparty_commitment = cmp::min(last_commitment_number, actual_commitment_number)
 242                 }
 243
 244                 Ok(self.inner.sign_counterparty_commitment(commitment_tx, inbound_htlc_preimages, outbound_htlc_preimages, secp_ctx).unwrap())
 245         }
 246
 247         fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
 248                 if !*self.available.lock().unwrap() {
 249                         return Err(());
 250                 }
 251                 let trusted_tx = self.verify_holder_commitment_tx(commitment_tx, secp_ctx);
 252                 let state = self.state.lock().unwrap();
 253                 let commitment_number = trusted_tx.commitment_number();
 254                 if state.last_holder_revoked_commitment - 1 != commitment_number && state.last_holder_revoked_commitment - 2 != commitment_number {
 255                         if !self.disable_revocation_policy_check {
 256                                 panic!("can only sign the next two unrevoked commitment numbers, revoked={} vs requested={} for {}",
 257                                        state.last_holder_revoked_commitment, commitment_number, self.inner.commitment_seed[0])
 258                         }
 259                 }
 260                 Ok(self.inner.sign_holder_commitment(commitment_tx, secp_ctx).unwrap())
 261         }
 262
 263         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
 264         fn unsafe_sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
 265                 Ok(self.inner.unsafe_sign_holder_commitment(commitment_tx, secp_ctx).unwrap())
 266         }
 267
 268         fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
 269                 if !*self.available.lock().unwrap() {
 270                         return Err(());
 271                 }
 272                 Ok(EcdsaChannelSigner::sign_justice_revoked_output(&self.inner, justice_tx, input, amount, per_commitment_key, secp_ctx).unwrap())
 273         }
 274
 275         fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
 276                 if !*self.available.lock().unwrap() {
 277                         return Err(());
 278                 }
 279                 Ok(EcdsaChannelSigner::sign_justice_revoked_htlc(&self.inner, justice_tx, input, amount, per_commitment_key, htlc, secp_ctx).unwrap())
 280         }
 281
 282         fn sign_holder_htlc_transaction(
 283                 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
 284                 secp_ctx: &Secp256k1<secp256k1::All>
 285         ) -> Result<Signature, ()> {
 286                 if !*self.available.lock().unwrap() {
 287                         return Err(());
 288                 }
 289                 let state = self.state.lock().unwrap();
 290                 if state.last_holder_revoked_commitment - 1 != htlc_descriptor.per_commitment_number &&
 291                         state.last_holder_revoked_commitment - 2 != htlc_descriptor.per_commitment_number
 292                 {
 293                         if !self.disable_revocation_policy_check {
 294                                 panic!("can only sign the next two unrevoked commitment numbers, revoked={} vs requested={} for {}",
 295                                        state.last_holder_revoked_commitment, htlc_descriptor.per_commitment_number, self.inner.commitment_seed[0])
 296                         }
 297                 }
 298                 assert_eq!(htlc_tx.input[input], htlc_descriptor.unsigned_tx_input());
 299                 assert_eq!(htlc_tx.output[input], htlc_descriptor.tx_output(secp_ctx));
 300                 {
 301                         let witness_script = htlc_descriptor.witness_script(secp_ctx);
 302                         let sighash_type = if self.channel_type_features().supports_anchors_zero_fee_htlc_tx() {
 303                                 EcdsaSighashType::SinglePlusAnyoneCanPay
 304                         } else {
 305                                 EcdsaSighashType::All
 306                         };
 307                         let sighash = &sighash::SighashCache::new(&*htlc_tx).p2wsh_signature_hash(
 308                                 input, &witness_script, htlc_descriptor.htlc.to_bitcoin_amount(), sighash_type
 309                         ).unwrap();
 310                         let countersignatory_htlc_key = HtlcKey::from_basepoint(
 311                                 &secp_ctx, &self.inner.counterparty_pubkeys().unwrap().htlc_basepoint, &htlc_descriptor.per_commitment_point,
 312                         );
 313
 314                         secp_ctx.verify_ecdsa(
 315                                 &hash_to_message!(sighash.as_byte_array()), &htlc_descriptor.counterparty_sig, &countersignatory_htlc_key.to_public_key()
 316                         ).unwrap();
 317                 }
 318                 Ok(EcdsaChannelSigner::sign_holder_htlc_transaction(&self.inner, htlc_tx, input, htlc_descriptor, secp_ctx).unwrap())
 319         }
 320
 321         fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
 322                 if !*self.available.lock().unwrap() {
 323                         return Err(());
 324                 }
 325                 Ok(EcdsaChannelSigner::sign_counterparty_htlc_transaction(&self.inner, htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
 326         }
 327
 328         fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
 329                 closing_tx.verify(self.inner.funding_outpoint().unwrap().into_bitcoin_outpoint())
 330                         .expect("derived different closing transaction");
 331                 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
 332         }
 333
 334         fn sign_holder_anchor_input(
 335                 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
 336         ) -> Result<Signature, ()> {
 337                 debug_assert!(MIN_CHAN_DUST_LIMIT_SATOSHIS > ANCHOR_OUTPUT_VALUE_SATOSHI);
 338                 // As long as our minimum dust limit is enforced and is greater than our anchor output
 339                 // value, an anchor output can only have an index within [0, 1].
 340                 assert!(anchor_tx.input[input].previous_output.vout == 0 || anchor_tx.input[input].previous_output.vout == 1);
 341                 if !*self.available.lock().unwrap() {
 342                         return Err(());
 343                 }
 344                 EcdsaChannelSigner::sign_holder_anchor_input(&self.inner, anchor_tx, input, secp_ctx)
 345         }
 346
 347         fn sign_channel_announcement_with_funding_key(
 348                 &self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
 349         ) -> Result<Signature, ()> {
 350                 self.inner.sign_channel_announcement_with_funding_key(msg, secp_ctx)
 351         }
 352 }
 353
 354 #[cfg(taproot)]
 355 impl TaprootChannelSigner for TestChannelSigner {
 356         fn generate_local_nonce_pair(&self, commitment_number: u64, secp_ctx: &Secp256k1<All>) -> PublicNonce {
 357                 todo!()
 358         }
 359
 360         fn partially_sign_counterparty_commitment(&self, counterparty_nonce: PublicNonce, commitment_tx: &CommitmentTransaction, inbound_htlc_preimages: Vec<PaymentPreimage>, outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<All>) -> Result<(PartialSignatureWithNonce, Vec<secp256k1::schnorr::Signature>), ()> {
 361                 todo!()
 362         }
 363
 364         fn finalize_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, counterparty_partial_signature: PartialSignatureWithNonce, secp_ctx: &Secp256k1<All>) -> Result<PartialSignature, ()> {
 365                 todo!()
 366         }
 367
 368         fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
 369                 todo!()
 370         }
 371
 372         fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
 373                 todo!()
 374         }
 375
 376         fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
 377                 todo!()
 378         }
 379
 380         fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
 381                 todo!()
 382         }
 383
 384         fn partially_sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<All>) -> Result<PartialSignature, ()> {
 385                 todo!()
 386         }
 387
 388         fn sign_holder_anchor_input(&self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
 389                 todo!()
 390         }
 391 }
 392
 393 impl Writeable for TestChannelSigner {
 394         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
 395                 // TestChannelSigner has two fields - `inner` ([`InMemorySigner`]) and `state`
 396                 // ([`EnforcementState`]). `inner` is serialized here and deserialized by
 397                 // [`SignerProvider::read_chan_signer`]. `state` is managed by [`SignerProvider`]
 398                 // and will be serialized as needed by the implementation of that trait.
 399                 self.inner.write(writer)?;
 400                 Ok(())
 401         }
 402 }
 403
 404 impl TestChannelSigner {
 405         fn verify_counterparty_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> TrustedCommitmentTransaction<'a> {
 406                 commitment_tx.verify(
 407                         &self.inner.get_channel_parameters().unwrap().as_counterparty_broadcastable(),
 408                         self.inner.counterparty_pubkeys().unwrap(), self.inner.pubkeys(), secp_ctx
 409                 ).expect("derived different per-tx keys or built transaction")
 410         }
 411
 412         fn verify_holder_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> TrustedCommitmentTransaction<'a> {
 413                 commitment_tx.verify(
 414                         &self.inner.get_channel_parameters().unwrap().as_holder_broadcastable(),
 415                         self.inner.pubkeys(), self.inner.counterparty_pubkeys().unwrap(), secp_ctx
 416                 ).expect("derived different per-tx keys or built transaction")
 417         }
 418 }
 419
 420 /// The state used by [`TestChannelSigner`] in order to enforce policy checks
 421 ///
 422 /// This structure is maintained by KeysInterface since we may have multiple copies of
 423 /// the signer and they must coordinate their state.
 424 #[derive(Clone)]
 425 pub struct EnforcementState {
 426         /// The last counterparty commitment number we signed, backwards counting
 427         pub last_counterparty_commitment: u64,
 428         /// The last counterparty commitment they revoked, backwards counting
 429         pub last_counterparty_revoked_commitment: u64,
 430         /// The last holder commitment number we revoked, backwards counting
 431         pub last_holder_revoked_commitment: u64,
 432         /// The last validated holder commitment number, backwards counting
 433         pub last_holder_commitment: u64,
 434 }
 435
 436 impl EnforcementState {
 437         /// Enforcement state for a new channel
 438         pub fn new() -> Self {
 439                 EnforcementState {
 440                         last_counterparty_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
 441                         last_counterparty_revoked_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
 442                         last_holder_revoked_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
 443                         last_holder_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
 444                 }
 445         }
 446 }