bitcoin crate 0.28.1
[rust-lightning] / lightning / src / ln / channel.rs
index d680095fc1ba06f842921cd604589f48a5386ceb..8ebaa96b62e276b3ca0c0fd9bc55bcd822c6c66e 100644 (file)
@@ -8,8 +8,8 @@
 // licenses.
 
 use bitcoin::blockdata::script::{Script,Builder};
-use bitcoin::blockdata::transaction::{Transaction, SigHashType};
-use bitcoin::util::bip143;
+use bitcoin::blockdata::transaction::{Transaction, EcdsaSighashType};
+use bitcoin::util::sighash;
 use bitcoin::consensus::encode;
 
 use bitcoin::hashes::Hash;
@@ -18,8 +18,8 @@ use bitcoin::hashes::sha256d::Hash as Sha256d;
 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::{PublicKey,SecretKey};
+use bitcoin::secp256k1::{Secp256k1,ecdsa::Signature};
 use bitcoin::secp256k1;
 
 use ln::{PaymentPreimage, PaymentHash};
@@ -62,6 +62,17 @@ pub struct ChannelValueStat {
        pub counterparty_dust_limit_msat: u64,
 }
 
+pub struct AvailableBalances {
+       /// The amount that would go to us if we close the channel, ignoring any on-chain fees.
+       pub balance_msat: u64,
+       /// Total amount available for our counterparty to send to us.
+       pub inbound_capacity_msat: u64,
+       /// Total amount available for us to send to our counterparty.
+       pub outbound_capacity_msat: u64,
+       /// The maximum value we can assign to the next outbound HTLC
+       pub next_outbound_htlc_limit_msat: u64,
+}
+
 #[derive(Debug, Clone, Copy, PartialEq)]
 enum FeeUpdateState {
        // Inbound states mirroring InboundHTLCState
@@ -736,8 +747,8 @@ pub const ANCHOR_OUTPUT_VALUE_SATOSHI: u64 = 330;
 
 /// Maximum `funding_satoshis` value according to the BOLT #2 specification, if
 /// `option_support_large_channel` (aka wumbo channels) is not supported.
-/// It's 2^24.
-pub const MAX_FUNDING_SATOSHIS_NO_WUMBO: u64 = 1 << 24;
+/// It's 2^24 - 1.
+pub const MAX_FUNDING_SATOSHIS_NO_WUMBO: u64 = (1 << 24) - 1;
 
 /// Total bitcoin supply in satoshis.
 pub const TOTAL_BITCOIN_SUPPLY_SATOSHIS: u64 = 21_000_000 * 1_0000_0000;
@@ -854,8 +865,11 @@ impl<Signer: Sign> Channel<Signer> {
                let holder_signer = keys_provider.get_channel_signer(false, channel_value_satoshis);
                let pubkeys = holder_signer.pubkeys().clone();
 
-               if channel_value_satoshis >= MAX_FUNDING_SATOSHIS_NO_WUMBO {
-                       return Err(APIError::APIMisuseError{err: format!("funding_value must be smaller than {}, it was {}", MAX_FUNDING_SATOSHIS_NO_WUMBO, channel_value_satoshis)});
+               if !their_features.supports_wumbo() && channel_value_satoshis > MAX_FUNDING_SATOSHIS_NO_WUMBO {
+                       return Err(APIError::APIMisuseError{err: format!("funding_value must not exceed {}, it was {}", MAX_FUNDING_SATOSHIS_NO_WUMBO, channel_value_satoshis)});
+               }
+               if channel_value_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
+                       return Err(APIError::APIMisuseError{err: format!("funding_value must be smaller than the total bitcoin supply, it was {}", channel_value_satoshis)});
                }
                let channel_value_msat = channel_value_satoshis * 1000;
                if push_msat > channel_value_msat {
@@ -1080,20 +1094,22 @@ impl<Signer: Sign> Channel<Signer> {
                }
 
                // Check sanity of message fields:
-               if msg.funding_satoshis >= MAX_FUNDING_SATOSHIS_NO_WUMBO {
-                       return Err(ChannelError::Close(format!("Funding must be smaller than {}. It was {}", MAX_FUNDING_SATOSHIS_NO_WUMBO, msg.funding_satoshis)));
+               if msg.funding_satoshis > config.peer_channel_config_limits.max_funding_satoshis {
+                       return Err(ChannelError::Close(format!("Per our config, funding must be at most {}. It was {}", config.peer_channel_config_limits.max_funding_satoshis, msg.funding_satoshis)));
+               }
+               if msg.funding_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
+                       return Err(ChannelError::Close(format!("Funding must be smaller than the total bitcoin supply. It was {}", msg.funding_satoshis)));
                }
                if msg.channel_reserve_satoshis > msg.funding_satoshis {
                        return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must be not greater than funding_satoshis: {}", msg.channel_reserve_satoshis, msg.funding_satoshis)));
                }
-               let funding_value = (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000;
-               if msg.push_msat > funding_value {
-                       return Err(ChannelError::Close(format!("push_msat {} was larger than funding value {}", msg.push_msat, funding_value)));
+               let full_channel_value_msat = (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000;
+               if msg.push_msat > full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("push_msat {} was larger than channel amount minus reserve ({})", msg.push_msat, full_channel_value_msat)));
                }
                if msg.dust_limit_satoshis > msg.funding_satoshis {
                        return Err(ChannelError::Close(format!("dust_limit_satoshis {} was larger than funding_satoshis {}. Peer never wants payout outputs?", msg.dust_limit_satoshis, msg.funding_satoshis)));
                }
-               let full_channel_value_msat = (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000;
                if msg.htlc_minimum_msat >= full_channel_value_msat {
                        return Err(ChannelError::Close(format!("Minimum htlc value ({}) was larger than full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
                }
@@ -1147,6 +1163,9 @@ impl<Signer: Sign> Channel<Signer> {
                if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
                        return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). dust_limit_satoshis is ({}).", holder_selected_channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
                }
+               if holder_selected_channel_reserve_satoshis * 1000 >= full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). Channel value is ({} - {}).", holder_selected_channel_reserve_satoshis, full_channel_value_msat, msg.push_msat)));
+               }
                if msg.channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
                        log_debug!(logger, "channel_reserve_satoshis ({}) is smaller than our dust limit ({}). We can broadcast stale states without any risk, implying this channel is very insecure for our counterparty.",
                                msg.channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS);
@@ -2025,7 +2044,7 @@ impl<Signer: Sign> Channel<Signer> {
                                log_bytes!(sig.serialize_compact()[..]), log_bytes!(self.counterparty_funding_pubkey().serialize()),
                                encode::serialize_hex(&initial_commitment_bitcoin_tx.transaction), log_bytes!(sighash[..]),
                                encode::serialize_hex(&funding_script), log_bytes!(self.channel_id()));
-                       secp_check!(self.secp_ctx.verify(&sighash, &sig, self.counterparty_funding_pubkey()), "Invalid funding_created signature from peer".to_owned());
+                       secp_check!(self.secp_ctx.verify_ecdsa(&sighash, &sig, self.counterparty_funding_pubkey()), "Invalid funding_created signature from peer".to_owned());
                }
 
                let counterparty_keys = self.build_remote_transaction_keys()?;
@@ -2157,7 +2176,7 @@ impl<Signer: Sign> Channel<Signer> {
                        let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
                        let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.channel_value_satoshis);
                        // They sign our commitment transaction, allowing us to broadcast the tx if we wish.
-                       if let Err(_) = self.secp_ctx.verify(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
+                       if let Err(_) = self.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
                                return Err(ChannelError::Close("Invalid funding_signed signature from peer".to_owned()));
                        }
                }
@@ -2334,40 +2353,39 @@ impl<Signer: Sign> Channel<Signer> {
                stats
        }
 
-       /// Get the available (ie not including pending HTLCs) inbound and outbound balance in msat.
+       /// Get the available balances, see [`AvailableBalances`]'s fields for more info.
        /// Doesn't bother handling the
        /// if-we-removed-it-already-but-haven't-fully-resolved-they-can-still-send-an-inbound-HTLC
        /// corner case properly.
-       /// The channel reserve is subtracted from each balance.
-       /// See also [`Channel::get_balance_msat`]
-       pub fn get_inbound_outbound_available_balance_msat(&self) -> (u64, u64) {
+       pub fn get_available_balances(&self) -> AvailableBalances {
                // Note that we have to handle overflow due to the above case.
-               (
-                       cmp::max(self.channel_value_satoshis as i64 * 1000
-                               - self.value_to_self_msat as i64
-                               - self.get_inbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64
-                               - self.holder_selected_channel_reserve_satoshis as i64 * 1000,
-                       0) as u64,
-                       cmp::max(self.value_to_self_msat as i64
-                               - self.get_outbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64
-                               - self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) as i64 * 1000,
-                       0) as u64
-               )
-       }
+               let outbound_stats = self.get_outbound_pending_htlc_stats(None);
 
-       /// Get our total balance in msat.
-       /// This is the amount that would go to us if we close the channel, ignoring any on-chain fees.
-       /// See also [`Channel::get_inbound_outbound_available_balance_msat`]
-       pub fn get_balance_msat(&self) -> u64 {
-               // Include our local balance, plus any inbound HTLCs we know the preimage for, minus any
-               // HTLCs sent or which will be sent after commitment signed's are exchanged.
                let mut balance_msat = self.value_to_self_msat;
                for ref htlc in self.pending_inbound_htlcs.iter() {
                        if let InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::Fulfill(_)) = htlc.state {
                                balance_msat += htlc.amount_msat;
                        }
                }
-               balance_msat - self.get_outbound_pending_htlc_stats(None).pending_htlcs_value_msat
+               balance_msat -= outbound_stats.pending_htlcs_value_msat;
+
+               let outbound_capacity_msat = cmp::max(self.value_to_self_msat as i64
+                               - outbound_stats.pending_htlcs_value_msat as i64
+                               - self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) as i64 * 1000,
+                       0) as u64;
+               AvailableBalances {
+                       inbound_capacity_msat: cmp::max(self.channel_value_satoshis as i64 * 1000
+                                       - self.value_to_self_msat as i64
+                                       - self.get_inbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64
+                                       - self.holder_selected_channel_reserve_satoshis as i64 * 1000,
+                               0) as u64,
+                       outbound_capacity_msat,
+                       next_outbound_htlc_limit_msat: cmp::max(cmp::min(outbound_capacity_msat as i64,
+                                       self.counterparty_max_htlc_value_in_flight_msat as i64
+                                               - outbound_stats.pending_htlcs_value_msat as i64),
+                               0) as u64,
+                       balance_msat,
+               }
        }
 
        pub fn get_holder_counterparty_selected_channel_reserve_satoshis(&self) -> (u64, Option<u64>) {
@@ -2796,7 +2814,7 @@ impl<Signer: Sign> Channel<Signer> {
                                log_bytes!(msg.signature.serialize_compact()[..]),
                                log_bytes!(self.counterparty_funding_pubkey().serialize()), encode::serialize_hex(&bitcoin_tx.transaction),
                                log_bytes!(sighash[..]), encode::serialize_hex(&funding_script), log_bytes!(self.channel_id()));
-                       if let Err(_) = self.secp_ctx.verify(&sighash, &msg.signature, &self.counterparty_funding_pubkey()) {
+                       if let Err(_) = self.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.counterparty_funding_pubkey()) {
                                return Err((None, ChannelError::Close("Invalid commitment tx signature from peer".to_owned())));
                        }
                        bitcoin_tx.txid
@@ -2846,12 +2864,12 @@ impl<Signer: Sign> Channel<Signer> {
                                        &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
 
                                let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &keys);
-                               let htlc_sighashtype = if self.opt_anchors() { SigHashType::SinglePlusAnyoneCanPay } else { SigHashType::All };
-                               let htlc_sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype)[..]);
+                               let htlc_sighashtype = if self.opt_anchors() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
+                               let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
                                log_trace!(logger, "Checking HTLC tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} in channel {}.",
                                        log_bytes!(msg.htlc_signatures[idx].serialize_compact()[..]), log_bytes!(keys.countersignatory_htlc_key.serialize()),
                                        encode::serialize_hex(&htlc_tx), log_bytes!(htlc_sighash[..]), encode::serialize_hex(&htlc_redeemscript), log_bytes!(self.channel_id()));
-                               if let Err(_) = self.secp_ctx.verify(&htlc_sighash, &msg.htlc_signatures[idx], &keys.countersignatory_htlc_key) {
+                               if let Err(_) = self.secp_ctx.verify_ecdsa(&htlc_sighash, &msg.htlc_signatures[idx], &keys.countersignatory_htlc_key) {
                                        return Err((None, ChannelError::Close("Invalid HTLC tx signature from peer".to_owned())));
                                }
                                htlcs_and_sigs.push((htlc, Some(msg.htlc_signatures[idx]), source));
@@ -4088,15 +4106,17 @@ impl<Signer: Sign> Channel<Signer> {
 
                let funding_key = self.get_holder_pubkeys().funding_pubkey.serialize();
                let counterparty_funding_key = self.counterparty_funding_pubkey().serialize();
+               let mut holder_sig = sig.serialize_der().to_vec();
+               holder_sig.push(EcdsaSighashType::All as u8);
+               let mut cp_sig = counterparty_sig.serialize_der().to_vec();
+               cp_sig.push(EcdsaSighashType::All as u8);
                if funding_key[..] < counterparty_funding_key[..] {
-                       tx.input[0].witness.push(sig.serialize_der().to_vec());
-                       tx.input[0].witness.push(counterparty_sig.serialize_der().to_vec());
+                       tx.input[0].witness.push(holder_sig);
+                       tx.input[0].witness.push(cp_sig);
                } else {
-                       tx.input[0].witness.push(counterparty_sig.serialize_der().to_vec());
-                       tx.input[0].witness.push(sig.serialize_der().to_vec());
+                       tx.input[0].witness.push(cp_sig);
+                       tx.input[0].witness.push(holder_sig);
                }
-               tx.input[0].witness[1].push(SigHashType::All as u8);
-               tx.input[0].witness[2].push(SigHashType::All as u8);
 
                tx.input[0].witness.push(self.get_funding_redeemscript().into_bytes());
                tx
@@ -4134,14 +4154,14 @@ impl<Signer: Sign> Channel<Signer> {
                }
                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) {
+               match self.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
                        Ok(_) => {},
                        Err(_e) => {
                                // 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;
                                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());
+                               secp_check!(self.secp_ctx.verify_ecdsa(&sighash, &msg.signature, self.counterparty_funding_pubkey()), "Invalid closing tx signature from peer".to_owned());
                        },
                };
 
@@ -4325,11 +4345,15 @@ impl<Signer: Sign> Channel<Signer> {
        }
 
        /// Allowed in any state (including after shutdown)
-       #[cfg(test)]
        pub fn get_holder_htlc_minimum_msat(&self) -> u64 {
                self.holder_htlc_minimum_msat
        }
 
+       /// Allowed in any state (including after shutdown), but will return none before TheirInitSent
+       pub fn get_holder_htlc_maximum_msat(&self) -> Option<u64> {
+               self.get_htlc_maximum_msat(self.holder_max_htlc_value_in_flight_msat)
+       }
+
        /// Allowed in any state (including after shutdown)
        pub fn get_announced_htlc_max_msat(&self) -> u64 {
                return cmp::min(
@@ -4347,6 +4371,21 @@ impl<Signer: Sign> Channel<Signer> {
                self.counterparty_htlc_minimum_msat
        }
 
+       /// Allowed in any state (including after shutdown), but will return none before TheirInitSent
+       pub fn get_counterparty_htlc_maximum_msat(&self) -> Option<u64> {
+               self.get_htlc_maximum_msat(self.counterparty_max_htlc_value_in_flight_msat)
+       }
+
+       fn get_htlc_maximum_msat(&self, party_max_htlc_value_in_flight_msat: u64) -> Option<u64> {
+               self.counterparty_selected_channel_reserve_satoshis.map(|counterparty_reserve| {
+                       let holder_reserve = self.holder_selected_channel_reserve_satoshis;
+                       cmp::min(
+                               (self.channel_value_satoshis - counterparty_reserve - holder_reserve) * 1000,
+                               party_max_htlc_value_in_flight_msat
+                       )
+               })
+       }
+
        pub fn get_value_satoshis(&self) -> u64 {
                self.channel_value_satoshis
        }
@@ -5008,12 +5047,12 @@ impl<Signer: Sign> Channel<Signer> {
 
                let msghash = hash_to_message!(&Sha256d::hash(&announcement.encode()[..])[..]);
 
-               if self.secp_ctx.verify(&msghash, &msg.node_signature, &self.get_counterparty_node_id()).is_err() {
+               if self.secp_ctx.verify_ecdsa(&msghash, &msg.node_signature, &self.get_counterparty_node_id()).is_err() {
                        return Err(ChannelError::Close(format!(
                                "Bad announcement_signatures. Failed to verify node_signature. UnsignedChannelAnnouncement used for verification is {:?}. their_node_key is {:?}",
                                 &announcement, self.get_counterparty_node_id())));
                }
-               if self.secp_ctx.verify(&msghash, &msg.bitcoin_signature, self.counterparty_funding_pubkey()).is_err() {
+               if self.secp_ctx.verify_ecdsa(&msghash, &msg.bitcoin_signature, self.counterparty_funding_pubkey()).is_err() {
                        return Err(ChannelError::Close(format!(
                                "Bad announcement_signatures. Failed to verify bitcoin_signature. UnsignedChannelAnnouncement used for verification is {:?}. their_bitcoin_key is ({:?})",
                                &announcement, self.counterparty_funding_pubkey())));
@@ -6317,10 +6356,10 @@ mod tests {
        use util::errors::APIError;
        use util::test_utils;
        use util::test_utils::OnGetShutdownScriptpubkey;
-       use bitcoin::secp256k1::{Secp256k1, Signature};
+       use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
        use bitcoin::secp256k1::ffi::Signature as FFISignature;
-       use bitcoin::secp256k1::key::{SecretKey,PublicKey};
-       use bitcoin::secp256k1::recovery::RecoverableSignature;
+       use bitcoin::secp256k1::{SecretKey,PublicKey};
+       use bitcoin::secp256k1::ecdsa::RecoverableSignature;
        use bitcoin::hashes::sha256::Hash as Sha256;
        use bitcoin::hashes::Hash;
        use bitcoin::hash_types::WPubkeyHash;
@@ -6670,9 +6709,9 @@ mod tests {
        #[cfg(not(feature = "grind_signatures"))]
        #[test]
        fn outbound_commitment_test() {
-               use bitcoin::util::bip143;
+               use bitcoin::util::sighash;
                use bitcoin::consensus::encode::serialize;
-               use bitcoin::blockdata::transaction::SigHashType;
+               use bitcoin::blockdata::transaction::EcdsaSighashType;
                use bitcoin::hashes::hex::FromHex;
                use bitcoin::hash_types::Txid;
                use bitcoin::secp256k1::Message;
@@ -6781,7 +6820,7 @@ mod tests {
                                let counterparty_signature = Signature::from_der(&hex::decode($counterparty_sig_hex).unwrap()[..]).unwrap();
                                let sighash = unsigned_tx.get_sighash_all(&redeemscript, chan.channel_value_satoshis);
                                log_trace!(logger, "unsigned_tx = {}", hex::encode(serialize(&unsigned_tx.transaction)));
-                               assert!(secp_ctx.verify(&sighash, &counterparty_signature, chan.counterparty_funding_pubkey()).is_ok(), "verify counterparty commitment sig");
+                               assert!(secp_ctx.verify_ecdsa(&sighash, &counterparty_signature, chan.counterparty_funding_pubkey()).is_ok(), "verify counterparty commitment sig");
 
                                let mut per_htlc: Vec<(HTLCOutputInCommitment, Option<Signature>)> = Vec::new();
                                per_htlc.clear(); // Don't warn about excess mut for no-HTLC calls
@@ -6820,9 +6859,9 @@ mod tests {
                                                chan.get_counterparty_selected_contest_delay().unwrap(),
                                                &htlc, $opt_anchors, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
                                        let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, $opt_anchors, &keys);
-                                       let htlc_sighashtype = if $opt_anchors { SigHashType::SinglePlusAnyoneCanPay } else { SigHashType::All };
-                                       let htlc_sighash = Message::from_slice(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype)[..]).unwrap();
-                                       assert!(secp_ctx.verify(&htlc_sighash, &remote_signature, &keys.countersignatory_htlc_key).is_ok(), "verify counterparty htlc sig");
+                                       let htlc_sighashtype = if $opt_anchors { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
+                                       let htlc_sighash = Message::from_slice(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]).unwrap();
+                                       assert!(secp_ctx.verify_ecdsa(&htlc_sighash, &remote_signature, &keys.countersignatory_htlc_key).is_ok(), "verify counterparty htlc sig");
 
                                        let mut preimage: Option<PaymentPreimage> = None;
                                        if !htlc.offered {