Batch-sign local HTLC txn with a well-doc'd API, returning sigs
[rust-lightning] / lightning / src / ln / channel.rs
index ac072c0ea4f4f3de84fa6ca2fcfcfeda16085930..c5908906a076b7251f7f918d815626a5f5b32fb4 100644 (file)
@@ -18,7 +18,7 @@ use secp256k1;
 use ln::features::{ChannelFeatures, InitFeatures};
 use ln::msgs;
 use ln::msgs::{DecodeError, OptionalField, DataLossProtect};
-use ln::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep};
+use ln::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, HTLC_FAIL_BACK_BUFFER};
 use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, PaymentPreimage, PaymentHash, BREAKDOWN_TIMEOUT, MAX_LOCAL_BREAKDOWN_TIMEOUT};
 use ln::chan_utils::{CounterpartyCommitmentSecrets, LocalCommitmentTransaction, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys};
 use ln::chan_utils;
@@ -207,8 +207,8 @@ enum ChannelState {
        /// to drop us, but we store this anyway.
        ShutdownComplete = 4096,
 }
-const BOTH_SIDES_SHUTDOWN_MASK: u32 = (ChannelState::LocalShutdownSent as u32 | ChannelState::RemoteShutdownSent as u32);
-const MULTI_STATE_FLAGS: u32 = (BOTH_SIDES_SHUTDOWN_MASK | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateFailed as u32);
+const BOTH_SIDES_SHUTDOWN_MASK: u32 = ChannelState::LocalShutdownSent as u32 | ChannelState::RemoteShutdownSent as u32;
+const MULTI_STATE_FLAGS: u32 = BOTH_SIDES_SHUTDOWN_MASK | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateFailed as u32;
 
 const INITIAL_COMMITMENT_NUMBER: u64 = (1 << 48) - 1;
 
@@ -382,7 +382,7 @@ pub const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172;
 
 /// Maximmum `funding_satoshis` value, according to the BOLT #2 specification
 /// it's 2^24.
-pub const MAX_FUNDING_SATOSHIS: u64 = (1 << 24);
+pub const MAX_FUNDING_SATOSHIS: u64 = 1 << 24;
 
 /// Used to return a simple Error back to ChannelManager. Will get converted to a
 /// msgs::ErrorAction::SendErrorMessage or msgs::ErrorAction::IgnoreError as appropriate with our
@@ -1727,8 +1727,6 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                        return Err(ChannelError::Close("Remote provided CLTV expiry in seconds instead of block height"));
                }
 
-               //TODO: Check msg.cltv_expiry further? Do this in channel manager?
-
                if self.channel_state & ChannelState::LocalShutdownSent as u32 != 0 {
                        if let PendingHTLCStatus::Forward(_) = pending_forward_state {
                                panic!("ChannelManager shouldn't be trying to add a forwardable HTLC after we've started closing");
@@ -3154,13 +3152,33 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                self.network_sync == UpdateStatus::DisabledMarked
        }
 
-       /// Called by channelmanager based on chain blocks being connected.
-       /// Note that we only need to use this to detect funding_signed, anything else is handled by
-       /// the channel_monitor.
-       /// In case of Err, the channel may have been closed, at which point the standard requirements
-       /// apply - no calls may be made except those explicitly stated to be allowed post-shutdown.
+       /// When we receive a new block, we (a) check whether the block contains the funding
+       /// transaction (which would start us counting blocks until we send the funding_signed), and
+       /// (b) check the height of the block against outbound holding cell HTLCs in case we need to
+       /// give up on them prematurely and time them out. Everything else (e.g. commitment
+       /// transaction broadcasts, channel closure detection, HTLC transaction broadcasting, etc) is
+       /// handled by the ChannelMonitor.
+       ///
+       /// If we return Err, the channel may have been closed, at which point the standard
+       /// requirements apply - no calls may be made except those explicitly stated to be allowed
+       /// post-shutdown.
        /// Only returns an ErrorAction of DisconnectPeer, if Err.
-       pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Result<Option<msgs::FundingLocked>, msgs::ErrorMessage> {
+       ///
+       /// May return some HTLCs (and their payment_hash) which have timed out and should be failed
+       /// back.
+       pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
+               let mut timed_out_htlcs = Vec::new();
+               self.holding_cell_htlc_updates.retain(|htlc_update| {
+                       match htlc_update {
+                               &HTLCUpdateAwaitingACK::AddHTLC { ref payment_hash, ref source, ref cltv_expiry, .. } => {
+                                       if *cltv_expiry <= height + HTLC_FAIL_BACK_BUFFER {
+                                               timed_out_htlcs.push((source.clone(), payment_hash.clone()));
+                                               false
+                                       } else { true }
+                               },
+                               _ => true
+                       }
+               });
                let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
                if header.bitcoin_hash() != self.last_block_connected {
                        if self.funding_tx_confirmations > 0 {
@@ -3243,19 +3261,19 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                                                if self.channel_state & (ChannelState::MonitorUpdateFailed as u32) == 0 {
                                                        let next_per_commitment_secret = self.build_local_commitment_secret(self.cur_local_commitment_transaction_number);
                                                        let next_per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &next_per_commitment_secret);
-                                                       return Ok(Some(msgs::FundingLocked {
+                                                       return Ok((Some(msgs::FundingLocked {
                                                                channel_id: self.channel_id,
                                                                next_per_commitment_point: next_per_commitment_point,
-                                                       }));
+                                                       }), timed_out_htlcs));
                                                } else {
                                                        self.monitor_pending_funding_locked = true;
-                                                       return Ok(None);
+                                                       return Ok((None, timed_out_htlcs));
                                                }
                                        }
                                }
                        }
                }
-               Ok(None)
+               Ok((None, timed_out_htlcs))
        }
 
        /// Called by channelmanager based on chain blocks being disconnected.
@@ -3539,8 +3557,6 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
                        return Err(ChannelError::Ignore("Cannot send value that would put us over their reserve value"));
                }
 
-               //TODO: Check cltv_expiry? Do this in channel manager?
-
                // Now update local state:
                if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == (ChannelState::AwaitingRemoteRevoke as u32) {
                        self.holding_cell_htlc_updates.push(HTLCUpdateAwaitingACK::AddHTLC {
@@ -4479,7 +4495,7 @@ mod tests {
                macro_rules! test_commitment {
                        ( $their_sig_hex: expr, $our_sig_hex: expr, $tx_hex: expr, {
                                $( { $htlc_idx: expr, $their_htlc_sig_hex: expr, $our_htlc_sig_hex: expr, $htlc_tx_hex: expr } ), *
-                       } ) => {
+                       } ) => { {
                                unsigned_tx = {
                                        let mut res = chan.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, chan.feerate_per_kw);
                                        let htlcs = res.2.drain(..)
@@ -4501,11 +4517,15 @@ mod tests {
                                assert_eq!(unsigned_tx.1.len(), per_htlc.len());
 
                                localtx = LocalCommitmentTransaction::new_missing_local_sig(unsigned_tx.0.clone(), &their_signature, &PublicKey::from_secret_key(&secp_ctx, chan.local_keys.funding_key()), chan.their_funding_pubkey(), keys.clone(), chan.feerate_per_kw, per_htlc);
-                               chan_keys.sign_local_commitment(&mut localtx, &chan.secp_ctx);
+                               let local_sig = chan_keys.sign_local_commitment(&localtx, &chan.secp_ctx).unwrap();
+                               localtx.add_local_sig(&redeemscript, local_sig);
 
                                assert_eq!(serialize(localtx.with_valid_witness())[..],
                                                hex::decode($tx_hex).unwrap()[..]);
 
+                               let htlc_sigs = chan_keys.sign_local_commitment_htlc_transactions(&localtx, chan.their_to_self_delay, &chan.secp_ctx).unwrap();
+                               let mut htlc_sig_iter = localtx.per_htlc.iter().zip(htlc_sigs.iter().enumerate());
+
                                $({
                                        let remote_signature = Signature::from_der(&hex::decode($their_htlc_sig_hex).unwrap()[..]).unwrap();
 
@@ -4527,12 +4547,19 @@ mod tests {
                                                assert!(preimage.is_some());
                                        }
 
-                                       chan_keys.sign_htlc_transaction(&mut localtx, $htlc_idx, preimage, chan.their_to_self_delay, &chan.secp_ctx);
+                                       let mut htlc_sig = htlc_sig_iter.next().unwrap();
+                                       while (htlc_sig.1).1.is_none() { htlc_sig = htlc_sig_iter.next().unwrap(); }
+                                       assert_eq!((htlc_sig.0).0.transaction_output_index, Some($htlc_idx));
 
-                                       assert_eq!(serialize(localtx.htlc_with_valid_witness($htlc_idx).as_ref().unwrap())[..],
+                                       assert_eq!(serialize(&localtx.get_signed_htlc_tx((htlc_sig.1).0, &(htlc_sig.1).1.unwrap(), &preimage, chan.their_to_self_delay))[..],
                                                        hex::decode($htlc_tx_hex).unwrap()[..]);
                                })*
-                       }
+                               loop {
+                                       let htlc_sig = htlc_sig_iter.next();
+                                       if htlc_sig.is_none() { break; }
+                                       assert!((htlc_sig.unwrap().1).1.is_none());
+                               }
+                       } }
                }
 
                {