Dry-up witnessScript in sign_remote_htlc_transaction
[rust-lightning] / lightning / src / ln / channelmonitor.rs
index 2a873f6b7d305f19836d98dfe4e0e155f27d141c..e7e575a988a86c1dfd690f6e5694791b70881838 100644 (file)
@@ -428,16 +428,63 @@ struct LocalSignedTx {
        htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
 }
 
-/// Cache remote basepoint to compute any transaction on
-/// remote outputs, either justice or preimage/timeout transactions.
+/// We use this to track remote commitment transactions and htlcs outputs and
+/// use it to generate any justice or 2nd-stage preimage/timeout transactions.
 #[derive(PartialEq)]
-struct RemoteTxCache {
+struct RemoteCommitmentTransaction {
        remote_delayed_payment_base_key: PublicKey,
        remote_htlc_base_key: PublicKey,
        on_remote_tx_csv: u16,
        per_htlc: HashMap<Txid, Vec<HTLCOutputInCommitment>>
 }
 
+impl Writeable for RemoteCommitmentTransaction {
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
+               self.remote_delayed_payment_base_key.write(w)?;
+               self.remote_htlc_base_key.write(w)?;
+               w.write_all(&byte_utils::be16_to_array(self.on_remote_tx_csv))?;
+               w.write_all(&byte_utils::be64_to_array(self.per_htlc.len() as u64))?;
+               for (ref txid, ref htlcs) in self.per_htlc.iter() {
+                       w.write_all(&txid[..])?;
+                       w.write_all(&byte_utils::be64_to_array(htlcs.len() as u64))?;
+                       for &ref htlc in htlcs.iter() {
+                               htlc.write(w)?;
+                       }
+               }
+               Ok(())
+       }
+}
+impl Readable for RemoteCommitmentTransaction {
+       fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let remote_commitment_transaction = {
+                       let remote_delayed_payment_base_key = Readable::read(r)?;
+                       let remote_htlc_base_key = Readable::read(r)?;
+                       let on_remote_tx_csv: u16 = Readable::read(r)?;
+                       let per_htlc_len: u64 = Readable::read(r)?;
+                       let mut per_htlc = HashMap::with_capacity(cmp::min(per_htlc_len as usize, MAX_ALLOC_SIZE / 64));
+                       for _  in 0..per_htlc_len {
+                               let txid: Txid = Readable::read(r)?;
+                               let htlcs_count: u64 = Readable::read(r)?;
+                               let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
+                               for _ in 0..htlcs_count {
+                                       let htlc = Readable::read(r)?;
+                                       htlcs.push(htlc);
+                               }
+                               if let Some(_) = per_htlc.insert(txid, htlcs) {
+                                       return Err(DecodeError::InvalidValue);
+                               }
+                       }
+                       RemoteCommitmentTransaction {
+                               remote_delayed_payment_base_key,
+                               remote_htlc_base_key,
+                               on_remote_tx_csv,
+                               per_htlc,
+                       }
+               };
+               Ok(remote_commitment_transaction)
+       }
+}
+
 /// When ChannelMonitor discovers an onchain outpoint being a step of a channel and that it needs
 /// to generate a tx to push channel state forward, we cache outpoint-solving tx material to build
 /// a new bumped one in case of lenghty confirmation delay
@@ -747,7 +794,7 @@ pub struct ChannelMonitor<ChanSigner: ChannelKeys> {
        current_remote_commitment_txid: Option<Txid>,
        prev_remote_commitment_txid: Option<Txid>,
 
-       remote_tx_cache: RemoteTxCache,
+       remote_tx_cache: RemoteCommitmentTransaction,
        funding_redeemscript: Script,
        channel_value_satoshis: u64,
        // first is the idx of the first of the two revocation points
@@ -904,17 +951,7 @@ impl<ChanSigner: ChannelKeys + Writeable> ChannelMonitor<ChanSigner> {
                self.current_remote_commitment_txid.write(writer)?;
                self.prev_remote_commitment_txid.write(writer)?;
 
-               self.remote_tx_cache.remote_delayed_payment_base_key.write(writer)?;
-               self.remote_tx_cache.remote_htlc_base_key.write(writer)?;
-               writer.write_all(&byte_utils::be16_to_array(self.remote_tx_cache.on_remote_tx_csv))?;
-               writer.write_all(&byte_utils::be64_to_array(self.remote_tx_cache.per_htlc.len() as u64))?;
-               for (ref txid, ref htlcs) in self.remote_tx_cache.per_htlc.iter() {
-                       writer.write_all(&txid[..])?;
-                       writer.write_all(&byte_utils::be64_to_array(htlcs.len() as u64))?;
-                       for &ref htlc in htlcs.iter() {
-                               htlc.write(writer)?;
-                       }
-               }
+               self.remote_tx_cache.write(writer)?;
                self.funding_redeemscript.write(writer)?;
                self.channel_value_satoshis.write(writer)?;
 
@@ -1079,7 +1116,7 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                let payment_key_hash = WPubkeyHash::hash(&keys.pubkeys().payment_point.serialize());
                let remote_payment_script = Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&payment_key_hash[..]).into_script();
 
-               let remote_tx_cache = RemoteTxCache { remote_delayed_payment_base_key: *remote_delayed_payment_base_key, remote_htlc_base_key: *remote_htlc_base_key, on_remote_tx_csv, per_htlc: HashMap::new() };
+               let remote_tx_cache = RemoteCommitmentTransaction { remote_delayed_payment_base_key: *remote_delayed_payment_base_key, remote_htlc_base_key: *remote_htlc_base_key, on_remote_tx_csv, per_htlc: HashMap::new() };
 
                let mut onchain_tx_handler = OnchainTxHandler::new(destination_script.clone(), keys.clone(), on_local_tx_csv);
 
@@ -2237,31 +2274,7 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for (BlockHash, ChannelMonitor
                let current_remote_commitment_txid = Readable::read(reader)?;
                let prev_remote_commitment_txid = Readable::read(reader)?;
 
-               let remote_tx_cache = {
-                       let remote_delayed_payment_base_key = Readable::read(reader)?;
-                       let remote_htlc_base_key = Readable::read(reader)?;
-                       let on_remote_tx_csv: u16 = Readable::read(reader)?;
-                       let per_htlc_len: u64 = Readable::read(reader)?;
-                       let mut per_htlc = HashMap::with_capacity(cmp::min(per_htlc_len as usize, MAX_ALLOC_SIZE / 64));
-                       for _  in 0..per_htlc_len {
-                               let txid: Txid = Readable::read(reader)?;
-                               let htlcs_count: u64 = Readable::read(reader)?;
-                               let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
-                               for _ in 0..htlcs_count {
-                                       let htlc = Readable::read(reader)?;
-                                       htlcs.push(htlc);
-                               }
-                               if let Some(_) = per_htlc.insert(txid, htlcs) {
-                                       return Err(DecodeError::InvalidValue);
-                               }
-                       }
-                       RemoteTxCache {
-                               remote_delayed_payment_base_key,
-                               remote_htlc_base_key,
-                               on_remote_tx_csv,
-                               per_htlc,
-                       }
-               };
+               let remote_tx_cache = Readable::read(reader)?;
                let funding_redeemscript = Readable::read(reader)?;
                let channel_value_satoshis = Readable::read(reader)?;