Implement channelmonitor (de)serialization (fixes #45)
authorMatt Corallo <git@bluematt.me>
Mon, 9 Jul 2018 20:40:21 +0000 (16:40 -0400)
committerMatt Corallo <git@bluematt.me>
Tue, 17 Jul 2018 18:39:50 +0000 (14:39 -0400)
src/ln/channelmonitor.rs
src/util/byte_utils.rs

index 61b0f4557d39f95abbb83dcbf1fc5116caa8f54c..891dac807f8f59109e2c5f7209eb23c8ed903766 100644 (file)
@@ -1,6 +1,7 @@
 use bitcoin::blockdata::block::BlockHeader;
 use bitcoin::blockdata::transaction::{TxIn,TxOut,SigHashType,Transaction};
 use bitcoin::blockdata::script::Script;
+use bitcoin::network::serialize;
 use bitcoin::util::hash::Sha256dHash;
 use bitcoin::util::bip143;
 
@@ -15,6 +16,7 @@ use ln::chan_utils::HTLCOutputInCommitment;
 use chain::chaininterface::{ChainListener, ChainWatchInterface, BroadcasterInterface};
 use chain::transaction::OutPoint;
 use util::sha2::Sha256;
+use util::byte_utils;
 
 use std::collections::HashMap;
 use std::sync::{Arc,Mutex};
@@ -141,6 +143,9 @@ struct LocalSignedTx {
        htlc_outputs: Vec<(HTLCOutputInCommitment, Signature, Signature)>,
 }
 
+const SERIALIZATION_VERSION: u8 = 1;
+const MIN_SERIALIZATION_VERSION: u8 = 1;
+
 pub struct ChannelMonitor {
        funding_txo: Option<OutPoint>,
        commitment_transaction_number_obscure_factor: u64,
@@ -439,6 +444,385 @@ impl ChannelMonitor {
                self.funding_txo
        }
 
+       /// Serializes into a vec, with various modes for the exposed pub fns
+       fn serialize(&self, for_local_storage: bool) -> Vec<u8> {
+               let mut res = Vec::new();
+               res.push(SERIALIZATION_VERSION);
+               res.push(MIN_SERIALIZATION_VERSION);
+
+               match self.funding_txo {
+                       Some(outpoint) => {
+                               res.extend_from_slice(&outpoint.txid[..]);
+                               res.extend_from_slice(&byte_utils::be16_to_array(outpoint.index));
+                       },
+                       None => {
+                               // We haven't even been initialized...not sure why anyone is serializing us, but
+                               // not much to give them.
+                               return res;
+                       },
+               }
+
+               // Set in initial Channel-object creation, so should always be set by now:
+               res.extend_from_slice(&byte_utils::be48_to_array(self.commitment_transaction_number_obscure_factor));
+
+               match self.key_storage {
+                       KeyStorage::PrivMode { ref revocation_base_key, ref htlc_base_key } => {
+                               res.push(0);
+                               res.extend_from_slice(&revocation_base_key[..]);
+                               res.extend_from_slice(&htlc_base_key[..]);
+                       },
+                       KeyStorage::SigsMode { .. } => unimplemented!(),
+               }
+
+               res.extend_from_slice(&self.delayed_payment_base_key.serialize());
+               res.extend_from_slice(&self.their_htlc_base_key.as_ref().unwrap().serialize());
+
+               match self.their_cur_revocation_points {
+                       Some((idx, pubkey, second_option)) => {
+                               res.extend_from_slice(&byte_utils::be48_to_array(idx));
+                               res.extend_from_slice(&pubkey.serialize());
+                               match second_option {
+                                       Some(second_pubkey) => {
+                                               res.extend_from_slice(&second_pubkey.serialize());
+                                       },
+                                       None => {
+                                               res.extend_from_slice(&[0; 33]);
+                                       },
+                               }
+                       },
+                       None => {
+                               res.extend_from_slice(&byte_utils::be48_to_array(0));
+                       },
+               }
+
+               res.extend_from_slice(&byte_utils::be16_to_array(self.our_to_self_delay));
+               res.extend_from_slice(&byte_utils::be16_to_array(self.their_to_self_delay.unwrap()));
+
+               for &(ref secret, ref idx) in self.old_secrets.iter() {
+                       res.extend_from_slice(secret);
+                       res.extend_from_slice(&byte_utils::be64_to_array(*idx));
+               }
+
+               macro_rules! serialize_htlc_in_commitment {
+                       ($htlc_output: expr) => {
+                               res.push($htlc_output.offered as u8);
+                               res.extend_from_slice(&byte_utils::be64_to_array($htlc_output.amount_msat));
+                               res.extend_from_slice(&byte_utils::be32_to_array($htlc_output.cltv_expiry));
+                               res.extend_from_slice(&$htlc_output.payment_hash);
+                               res.extend_from_slice(&byte_utils::be32_to_array($htlc_output.transaction_output_index));
+                       }
+               }
+
+               res.extend_from_slice(&byte_utils::be64_to_array(self.remote_claimable_outpoints.len() as u64));
+               for (txid, htlc_outputs) in self.remote_claimable_outpoints.iter() {
+                       res.extend_from_slice(&txid[..]);
+                       res.extend_from_slice(&byte_utils::be64_to_array(htlc_outputs.len() as u64));
+                       for htlc_output in htlc_outputs.iter() {
+                               serialize_htlc_in_commitment!(htlc_output);
+                       }
+               }
+
+               {
+                       let remote_commitment_txn_on_chain = self.remote_commitment_txn_on_chain.lock().unwrap();
+                       res.extend_from_slice(&byte_utils::be64_to_array(remote_commitment_txn_on_chain.len() as u64));
+                       for (txid, commitment_number) in remote_commitment_txn_on_chain.iter() {
+                               res.extend_from_slice(&txid[..]);
+                               res.extend_from_slice(&byte_utils::be48_to_array(*commitment_number));
+                       }
+               }
+
+               if for_local_storage {
+                       res.extend_from_slice(&byte_utils::be64_to_array(self.remote_hash_commitment_number.len() as u64));
+                       for (payment_hash, commitment_number) in self.remote_hash_commitment_number.iter() {
+                               res.extend_from_slice(payment_hash);
+                               res.extend_from_slice(&byte_utils::be48_to_array(*commitment_number));
+                       }
+               } else {
+                       res.extend_from_slice(&byte_utils::be64_to_array(0));
+               }
+
+               macro_rules! serialize_local_tx {
+                       ($local_tx: expr) => {
+                               let tx_ser = serialize::serialize(&$local_tx.tx).unwrap();
+                               res.extend_from_slice(&byte_utils::be64_to_array(tx_ser.len() as u64));
+                               res.extend_from_slice(&tx_ser);
+
+                               res.extend_from_slice(&$local_tx.revocation_key.serialize());
+                               res.extend_from_slice(&$local_tx.a_htlc_key.serialize());
+                               res.extend_from_slice(&$local_tx.b_htlc_key.serialize());
+                               res.extend_from_slice(&$local_tx.delayed_payment_key.serialize());
+
+                               res.extend_from_slice(&byte_utils::be64_to_array($local_tx.feerate_per_kw));
+                               res.extend_from_slice(&byte_utils::be64_to_array($local_tx.htlc_outputs.len() as u64));
+                               for &(ref htlc_output, ref their_sig, ref our_sig) in $local_tx.htlc_outputs.iter() {
+                                       serialize_htlc_in_commitment!(htlc_output);
+                                       res.extend_from_slice(&their_sig.serialize_compact(&self.secp_ctx));
+                                       res.extend_from_slice(&our_sig.serialize_compact(&self.secp_ctx));
+                               }
+                       }
+               }
+
+               if let Some(ref prev_local_tx) = self.prev_local_signed_commitment_tx {
+                       res.push(1);
+                       serialize_local_tx!(prev_local_tx);
+               } else {
+                       res.push(0);
+               }
+
+               if let Some(ref cur_local_tx) = self.current_local_signed_commitment_tx {
+                       res.push(1);
+                       serialize_local_tx!(cur_local_tx);
+               } else {
+                       res.push(0);
+               }
+
+               res.extend_from_slice(&byte_utils::be64_to_array(self.payment_preimages.len() as u64));
+               for payment_preimage in self.payment_preimages.values() {
+                       res.extend_from_slice(payment_preimage);
+               }
+
+               res.extend_from_slice(&byte_utils::be64_to_array(self.destination_script.len() as u64));
+               res.extend_from_slice(&self.destination_script[..]);
+
+               res
+       }
+
+       /// Encodes this monitor into a byte array, suitable for writing to disk.
+       pub fn serialize_for_disk(&self) -> Vec<u8> {
+               self.serialize(true)
+       }
+
+       /// Encodes this monitor into a byte array, suitable for sending to a remote watchtower
+       pub fn serialize_for_watchtower(&self) -> Vec<u8> {
+               self.serialize(false)
+       }
+
+       /// Attempts to decode a serialized monitor
+       pub fn deserialize(data: &[u8]) -> Option<Self> {
+               let mut read_pos = 0;
+               macro_rules! read_bytes {
+                       ($byte_count: expr) => {
+                               {
+                                       if ($byte_count as usize) + read_pos > data.len() {
+                                               return None;
+                                       }
+                                       read_pos += $byte_count as usize;
+                                       &data[read_pos - $byte_count as usize..read_pos]
+                               }
+                       }
+               }
+
+               let secp_ctx = Secp256k1::new();
+               macro_rules! unwrap_obj {
+                       ($key: expr) => {
+                               match $key {
+                                       Ok(res) => res,
+                                       Err(_) => return None,
+                               }
+                       }
+               }
+
+               let _ver = read_bytes!(1)[0];
+               let min_ver = read_bytes!(1)[0];
+               if min_ver > SERIALIZATION_VERSION {
+                       return None;
+               }
+
+               // Technically this can fail and serialize fail a round-trip, but only for serialization of
+               // barely-init'd ChannelMonitors that we can't do anything with.
+               let funding_txo = Some(OutPoint {
+                       txid: Sha256dHash::from(read_bytes!(32)),
+                       index: byte_utils::slice_to_be16(read_bytes!(2)),
+               });
+               let commitment_transaction_number_obscure_factor = byte_utils::slice_to_be48(read_bytes!(6));
+
+               let key_storage = match read_bytes!(1)[0] {
+                       0 => {
+                               KeyStorage::PrivMode {
+                                       revocation_base_key: unwrap_obj!(SecretKey::from_slice(&secp_ctx, read_bytes!(32))),
+                                       htlc_base_key: unwrap_obj!(SecretKey::from_slice(&secp_ctx, read_bytes!(32))),
+                               }
+                       },
+                       _ => return None,
+               };
+
+               let delayed_payment_base_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)));
+               let their_htlc_base_key = Some(unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))));
+
+               let their_cur_revocation_points = {
+                       let first_idx = byte_utils::slice_to_be48(read_bytes!(6));
+                       if first_idx == 0 {
+                               None
+                       } else {
+                               let first_point = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)));
+                               let second_point_slice = read_bytes!(33);
+                               if second_point_slice[0..32] == [0; 32] && second_point_slice[32] == 0 {
+                                       Some((first_idx, first_point, None))
+                               } else {
+                                       Some((first_idx, first_point, Some(unwrap_obj!(PublicKey::from_slice(&secp_ctx, second_point_slice)))))
+                               }
+                       }
+               };
+
+               let our_to_self_delay = byte_utils::slice_to_be16(read_bytes!(2));
+               let their_to_self_delay = Some(byte_utils::slice_to_be16(read_bytes!(2)));
+
+               let mut old_secrets = [([0; 32], 1 << 48); 49];
+               for &mut (ref mut secret, ref mut idx) in old_secrets.iter_mut() {
+                       secret.copy_from_slice(read_bytes!(32));
+                       *idx = byte_utils::slice_to_be64(read_bytes!(8));
+               }
+
+               macro_rules! read_htlc_in_commitment {
+                       () => {
+                               {
+                                       let offered = match read_bytes!(1)[0] {
+                                               0 => false, 1 => true,
+                                               _ => return None,
+                                       };
+                                       let amount_msat = byte_utils::slice_to_be64(read_bytes!(8));
+                                       let cltv_expiry = byte_utils::slice_to_be32(read_bytes!(4));
+                                       let mut payment_hash = [0; 32];
+                                       payment_hash[..].copy_from_slice(read_bytes!(32));
+                                       let transaction_output_index = byte_utils::slice_to_be32(read_bytes!(4));
+
+                                       HTLCOutputInCommitment {
+                                               offered, amount_msat, cltv_expiry, payment_hash, transaction_output_index
+                                       }
+                               }
+                       }
+               }
+
+               let remote_claimable_outpoints_len = byte_utils::slice_to_be64(read_bytes!(8));
+               if remote_claimable_outpoints_len > data.len() as u64 / 64 { return None; }
+               let mut remote_claimable_outpoints = HashMap::with_capacity(remote_claimable_outpoints_len as usize);
+               for _ in 0..remote_claimable_outpoints_len {
+                       let txid = Sha256dHash::from(read_bytes!(32));
+                       let outputs_count = byte_utils::slice_to_be64(read_bytes!(8));
+                       if outputs_count > data.len() as u64 * 32 { return None; }
+                       let mut outputs = Vec::with_capacity(outputs_count as usize);
+                       for _ in 0..outputs_count {
+                               outputs.push(read_htlc_in_commitment!());
+                       }
+                       if let Some(_) = remote_claimable_outpoints.insert(txid, outputs) {
+                               return None;
+                       }
+               }
+
+               let remote_commitment_txn_on_chain_len = byte_utils::slice_to_be64(read_bytes!(8));
+               if remote_commitment_txn_on_chain_len > data.len() as u64 / 32 { return None; }
+               let mut remote_commitment_txn_on_chain = HashMap::with_capacity(remote_commitment_txn_on_chain_len as usize);
+               for _ in 0..remote_commitment_txn_on_chain_len {
+                       let txid = Sha256dHash::from(read_bytes!(32));
+                       let commitment_number = byte_utils::slice_to_be48(read_bytes!(6));
+                       if let Some(_) = remote_commitment_txn_on_chain.insert(txid, commitment_number) {
+                               return None;
+                       }
+               }
+
+               let remote_hash_commitment_number_len = byte_utils::slice_to_be64(read_bytes!(8));
+               if remote_hash_commitment_number_len > data.len() as u64 / 32 { return None; }
+               let mut remote_hash_commitment_number = HashMap::with_capacity(remote_hash_commitment_number_len as usize);
+               for _ in 0..remote_hash_commitment_number_len {
+                       let mut txid = [0; 32];
+                       txid[..].copy_from_slice(read_bytes!(32));
+                       let commitment_number = byte_utils::slice_to_be48(read_bytes!(6));
+                       if let Some(_) = remote_hash_commitment_number.insert(txid, commitment_number) {
+                               return None;
+                       }
+               }
+
+               macro_rules! read_local_tx {
+                       () => {
+                               {
+                                       let tx_len = byte_utils::slice_to_be64(read_bytes!(8));
+                                       let tx: Transaction = unwrap_obj!(serialize::deserialize(read_bytes!(tx_len)));
+
+                                       let revocation_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)));
+                                       let a_htlc_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)));
+                                       let b_htlc_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)));
+                                       let delayed_payment_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)));
+                                       let feerate_per_kw = byte_utils::slice_to_be64(read_bytes!(8));
+
+                                       let htlc_outputs_len = byte_utils::slice_to_be64(read_bytes!(8));
+                                       if htlc_outputs_len > data.len() as u64 / 128 { return None; }
+                                       let mut htlc_outputs = Vec::with_capacity(htlc_outputs_len as usize);
+                                       for _ in 0..htlc_outputs_len {
+                                               htlc_outputs.push((read_htlc_in_commitment!(),
+                                                               unwrap_obj!(Signature::from_compact(&secp_ctx, read_bytes!(64))),
+                                                               unwrap_obj!(Signature::from_compact(&secp_ctx, read_bytes!(64)))));
+                                       }
+
+                                       LocalSignedTx {
+                                               txid: tx.txid(),
+                                               tx, revocation_key, a_htlc_key, b_htlc_key, delayed_payment_key, feerate_per_kw, htlc_outputs
+                                       }
+                               }
+                       }
+               }
+
+               let prev_local_signed_commitment_tx = match read_bytes!(1)[0] {
+                       0 => None,
+                       1 => {
+                               Some(read_local_tx!())
+                       },
+                       _ => return None,
+               };
+
+               let current_local_signed_commitment_tx = match read_bytes!(1)[0] {
+                       0 => None,
+                       1 => {
+                               Some(read_local_tx!())
+                       },
+                       _ => return None,
+               };
+
+               let payment_preimages_len = byte_utils::slice_to_be64(read_bytes!(8));
+               if payment_preimages_len > data.len() as u64 / 32 { return None; }
+               let mut payment_preimages = HashMap::with_capacity(payment_preimages_len as usize);
+               let mut sha = Sha256::new();
+               for _ in 0..payment_preimages_len {
+                       let mut preimage = [0; 32];
+                       preimage[..].copy_from_slice(read_bytes!(32));
+                       sha.reset();
+                       sha.input(&preimage);
+                       let mut hash = [0; 32];
+                       sha.result(&mut hash);
+                       if let Some(_) = payment_preimages.insert(hash, preimage) {
+                               return None;
+                       }
+               }
+
+               let destination_script_len = byte_utils::slice_to_be64(read_bytes!(8));
+               let destination_script = Script::from(read_bytes!(destination_script_len).to_vec());
+
+               Some(ChannelMonitor {
+                       funding_txo,
+                       commitment_transaction_number_obscure_factor,
+
+                       key_storage,
+                       delayed_payment_base_key,
+                       their_htlc_base_key,
+                       their_cur_revocation_points,
+
+                       our_to_self_delay,
+                       their_to_self_delay,
+
+                       old_secrets,
+                       remote_claimable_outpoints,
+                       remote_commitment_txn_on_chain: Mutex::new(remote_commitment_txn_on_chain),
+                       remote_hash_commitment_number,
+
+                       prev_local_signed_commitment_tx,
+                       current_local_signed_commitment_tx,
+
+                       payment_preimages,
+
+                       destination_script,
+                       secp_ctx,
+               })
+       }
+
        //TODO: Functions to serialize/deserialize (with different forms depending on which information
        //we want to leave out (eg funding_txo, etc).
 
index 74a01196f943433ec71dc6d8f22bd8cea6d7fd1d..b9ca3f6b650a19c2e14380493f4e7bf0f1e9da90 100644 (file)
@@ -11,6 +11,15 @@ pub fn slice_to_be32(v: &[u8]) -> u32 {
        ((v[3] as u32) << 8*0)
 }
 #[inline]
+pub fn slice_to_be48(v: &[u8]) -> u64 {
+       ((v[0] as u64) << 8*5) |
+       ((v[1] as u64) << 8*4) |
+       ((v[2] as u64) << 8*3) |
+       ((v[3] as u64) << 8*2) |
+       ((v[4] as u64) << 8*1) |
+       ((v[5] as u64) << 8*0)
+}
+#[inline]
 pub fn slice_to_be64(v: &[u8]) -> u64 {
        ((v[0] as u64) << 8*7) |
        ((v[1] as u64) << 8*6) |
@@ -39,6 +48,18 @@ pub fn be32_to_array(u: u32) -> [u8; 4] {
        v
 }
 #[inline]
+pub fn be48_to_array(u: u64) -> [u8; 6] {
+       assert!(u & 0xffff_0000_0000_0000 == 0);
+       let mut v = [0; 6];
+       v[0] = ((u >> 8*5) & 0xff) as u8;
+       v[1] = ((u >> 8*4) & 0xff) as u8;
+       v[2] = ((u >> 8*3) & 0xff) as u8;
+       v[3] = ((u >> 8*2) & 0xff) as u8;
+       v[4] = ((u >> 8*1) & 0xff) as u8;
+       v[5] = ((u >> 8*0) & 0xff) as u8;
+       v
+}
+#[inline]
 pub fn be64_to_array(u: u64) -> [u8; 8] {
        let mut v = [0; 8];
        v[0] = ((u >> 8*7) & 0xff) as u8;