Provide remote channel public keys to signer
[rust-lightning] / lightning / src / chain / keysinterface.rs
index 58624d219c475fa9dc4de448e6fbc2f08f3faadf..689a16603743e228ffff64dfba9ea710474fdc43 100644 (file)
@@ -12,6 +12,7 @@ use bitcoin::util::bip143;
 use bitcoin_hashes::{Hash, HashEngine};
 use bitcoin_hashes::sha256::HashEngine as Sha256State;
 use bitcoin_hashes::sha256::Hash as Sha256;
+use bitcoin_hashes::sha256d::Hash as Sha256dHash;
 use bitcoin_hashes::hash160::Hash as Hash160;
 
 use secp256k1::key::{SecretKey, PublicKey};
@@ -20,9 +21,11 @@ use secp256k1;
 
 use util::byte_utils;
 use util::logger::Logger;
+use util::ser::Writeable;
 
 use ln::chan_utils;
-use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment};
+use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys};
+use ln::msgs;
 
 use std::sync::Arc;
 use std::sync::atomic::{AtomicUsize, Ordering};
@@ -139,7 +142,27 @@ pub trait ChannelKeys : Send {
        /// TODO: Document the things someone using this interface should enforce before signing.
        /// TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
        /// making the callee generate it via some util function we expose)!
-       fn sign_remote_commitment<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_script: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()>;
+       fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, channel_value_satoshis: u64, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()>;
+
+       /// Create a signature for a (proposed) closing transaction.
+       ///
+       /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
+       /// chosen to forgo their output as dust.
+       fn sign_closing_transaction<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
+
+       /// Signs a channel announcement message with our funding key, proving it comes from one
+       /// of the channel participants.
+       ///
+       /// Note that if this fails or is rejected, the channel will not be publicly announced and
+       /// our counterparty may (though likely will not) close the channel on us for violating the
+       /// protocol.
+       fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
+
+       /// Set the remote channel basepoints.  This is done immediately on incoming channels
+       /// and as soon as the channel is accepted on outgoing channels.
+       ///
+       /// Will be called before any signatures are applied.
+       fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
 }
 
 #[derive(Clone)]
@@ -157,6 +180,8 @@ pub struct InMemoryChannelKeys {
        pub htlc_base_key: SecretKey,
        /// Commitment seed
        pub commitment_seed: [u8; 32],
+       /// Remote funding pubkey
+       pub remote_channel_pubkeys: Option<ChannelPublicKeys>,
 }
 
 impl ChannelKeys for InMemoryChannelKeys {
@@ -167,10 +192,14 @@ impl ChannelKeys for InMemoryChannelKeys {
        fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
        fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
 
-
-       fn sign_remote_commitment<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_script: &Script, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
+       fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, channel_value_satoshis: u64, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
                if commitment_tx.input.len() != 1 { return Err(()); }
-               let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_script, channel_value_satoshis)[..]);
+
+               let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
+               let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
+               let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
+
+               let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, channel_value_satoshis)[..]);
                let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
 
                let commitment_txid = commitment_tx.txid();
@@ -191,6 +220,26 @@ impl ChannelKeys for InMemoryChannelKeys {
 
                Ok((commitment_sig, htlc_sigs))
        }
+
+       fn sign_closing_transaction<T: secp256k1::Signing>(&self, channel_value_satoshis: u64, channel_funding_redeemscript: &Script, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
+               if closing_tx.input.len() != 1 { return Err(()); }
+               if closing_tx.input[0].witness.len() != 0 { return Err(()); }
+               if closing_tx.output.len() > 2 { return Err(()); }
+
+               let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx)
+                       .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, channel_value_satoshis)[..]);
+               Ok(secp_ctx.sign(&sighash, &self.funding_key))
+       }
+
+       fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
+               let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
+               Ok(secp_ctx.sign(&msghash, &self.funding_key))
+       }
+
+       fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
+               assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
+               self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
+       }
 }
 
 impl_writeable!(InMemoryChannelKeys, 0, {
@@ -199,7 +248,8 @@ impl_writeable!(InMemoryChannelKeys, 0, {
        payment_base_key,
        delayed_payment_base_key,
        htlc_base_key,
-       commitment_seed
+       commitment_seed,
+       remote_channel_pubkeys
 });
 
 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
@@ -348,6 +398,7 @@ impl KeysInterface for KeysManager {
                        delayed_payment_base_key,
                        htlc_base_key,
                        commitment_seed,
+                       remote_channel_pubkeys: None,
                }
        }