More regularly send an Error message when we force-close a channel
[rust-lightning] / lightning / src / ln / channel.rs
index ca1887d8b2595c1485f7e120841b9368019237c5..1279f310d4bfdbcfd134a9b53c95674fa0dd21bf 100644 (file)
@@ -376,13 +376,10 @@ pub(super) struct Channel<Signer: Sign> {
 
        last_sent_closing_fee: Option<(u32, u64, Signature)>, // (feerate, fee, holder_sig)
 
-       /// The hash of the block in which the funding transaction reached our CONF_TARGET. We use this
-       /// to detect unconfirmation after a serialize-unserialize roundtrip where we may not see a full
-       /// series of block_connected/block_disconnected calls. Obviously this is not a guarantee as we
-       /// could miss the funding_tx_confirmed_in block as well, but it serves as a useful fallback.
+       /// The hash of the block in which the funding transaction was included.
        funding_tx_confirmed_in: Option<BlockHash>,
+       funding_tx_confirmation_height: u64,
        short_channel_id: Option<u64>,
-       funding_tx_confirmations: u64,
 
        counterparty_dust_limit_satoshis: u64,
        #[cfg(test)]
@@ -441,10 +438,6 @@ struct CommitmentTxInfoCached {
 }
 
 pub const OUR_MAX_HTLCS: u16 = 50; //TODO
-/// Confirmation count threshold at which we close a channel. Ideally we'd keep the channel around
-/// on ice until the funding transaction gets more confirmations, but the LN protocol doesn't
-/// really allow for this, so instead we're stuck closing it out at that point.
-const UNCONF_THRESHOLD: u32 = 6;
 const SPENDING_INPUT_FOR_A_OUTPUT_WEIGHT: u64 = 79; // prevout: 36, nSequence: 4, script len: 1, witness lengths: (3+1)/4, sig: 73/4, if-selector: 1, redeemScript: (6 ops + 2*33 pubkeys + 1*2 delay)/4
 const B_OUTPUT_PLUS_SPENDING_INPUT_WEIGHT: u64 = 104; // prevout: 40, nSequence: 4, script len: 1, witness lengths: 3/4, sig: 73/4, pubkey: 33/4, output: 31 (TODO: Wrong? Useless?)
 
@@ -581,8 +574,8 @@ impl<Signer: Sign> Channel<Signer> {
                        last_sent_closing_fee: None,
 
                        funding_tx_confirmed_in: None,
+                       funding_tx_confirmation_height: 0,
                        short_channel_id: None,
-                       funding_tx_confirmations: 0,
 
                        feerate_per_kw: feerate,
                        counterparty_dust_limit_satoshis: 0,
@@ -818,8 +811,8 @@ impl<Signer: Sign> Channel<Signer> {
                        last_sent_closing_fee: None,
 
                        funding_tx_confirmed_in: None,
+                       funding_tx_confirmation_height: 0,
                        short_channel_id: None,
-                       funding_tx_confirmations: 0,
 
                        feerate_per_kw: msg.feerate_per_kw,
                        channel_value_satoshis: msg.funding_satoshis,
@@ -3509,38 +3502,7 @@ impl<Signer: Sign> Channel<Signer> {
                self.network_sync == UpdateStatus::DisabledMarked
        }
 
-       /// 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.
-       ///
-       /// 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, txdata: &TransactionData, height: 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
-                       }
-               });
-
-               if self.funding_tx_confirmations > 0 {
-                       self.funding_tx_confirmations += 1;
-               }
-
+       pub fn transactions_confirmed(&mut self, block_hash: &BlockHash, height: u32, txdata: &TransactionData) -> Result<(), msgs::ErrorMessage> {
                let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
                if non_shutdown_state & !(ChannelState::TheirFundingLocked as u32) == ChannelState::FundingSent as u32 {
                        for &(index_in_block, tx) in txdata.iter() {
@@ -3575,7 +3537,8 @@ impl<Signer: Sign> Channel<Signer> {
                                                                }
                                                        }
                                                }
-                                               self.funding_tx_confirmations = 1;
+                                               self.funding_tx_confirmation_height = height as u64;
+                                               self.funding_tx_confirmed_in = Some(*block_hash);
                                                self.short_channel_id = match scid_from_parts(height as u64, index_in_block as u64, txo_idx as u64) {
                                                        Ok(scid) => Some(scid),
                                                        Err(_) => panic!("Block was bogus - either height was > 16 million, had > 16 million transactions, or had > 65k outputs"),
@@ -3584,10 +3547,53 @@ impl<Signer: Sign> Channel<Signer> {
                                }
                        }
                }
+               Ok(())
+       }
 
-               self.update_time_counter = cmp::max(self.update_time_counter, header.time);
-               if self.funding_tx_confirmations > 0 {
-                       if self.funding_tx_confirmations == self.minimum_depth as u64 {
+       /// When a new block is connected, we 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, 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.
+       ///
+       /// May return some HTLCs (and their payment_hash) which have timed out and should be failed
+       /// back.
+       pub fn update_best_block(&mut self, height: u32, highest_header_time: u32) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
+               let mut timed_out_htlcs = Vec::new();
+               let unforwarded_htlc_cltv_limit = height + HTLC_FAIL_BACK_BUFFER;
+               self.holding_cell_htlc_updates.retain(|htlc_update| {
+                       match htlc_update {
+                               &HTLCUpdateAwaitingACK::AddHTLC { ref payment_hash, ref source, ref cltv_expiry, .. } => {
+                                       if *cltv_expiry <= unforwarded_htlc_cltv_limit {
+                                               timed_out_htlcs.push((source.clone(), payment_hash.clone()));
+                                               false
+                                       } else { true }
+                               },
+                               _ => true
+                       }
+               });
+
+               self.update_time_counter = cmp::max(self.update_time_counter, highest_header_time);
+               if self.funding_tx_confirmation_height > 0 {
+                       let funding_tx_confirmations = height as i64 - self.funding_tx_confirmation_height as i64 + 1;
+                       if funding_tx_confirmations <= 0 {
+                               self.funding_tx_confirmation_height = 0;
+                       }
+
+                       let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
+                       if (non_shutdown_state >= ChannelState::ChannelFunded as u32 ||
+                          (non_shutdown_state & ChannelState::OurFundingLocked as u32) == ChannelState::OurFundingLocked as u32) &&
+                           funding_tx_confirmations < self.minimum_depth as i64 / 2 {
+                               return Err(msgs::ErrorMessage {
+                                       channel_id: self.channel_id(),
+                                       data: format!("Funding transaction was un-confirmed. Locked at {} confs, now have {} confs.", self.minimum_depth, funding_tx_confirmations),
+                               });
+                       }
+
+                       if funding_tx_confirmations == self.minimum_depth as i64 {
                                let need_commitment_update = if non_shutdown_state == ChannelState::FundingSent as u32 {
                                        self.channel_state |= ChannelState::OurFundingLocked as u32;
                                        true
@@ -3606,7 +3612,6 @@ impl<Signer: Sign> Channel<Signer> {
                                        // funding_tx_confirmed_in and return.
                                        false
                                };
-                               self.funding_tx_confirmed_in = Some(header.block_hash());
 
                                //TODO: Note that this must be a duplicate of the previous commitment point they sent us,
                                //as otherwise we will have a commitment transaction that they can't revoke (well, kinda,
@@ -3626,21 +3631,35 @@ impl<Signer: Sign> Channel<Signer> {
                                }
                        }
                }
+
                Ok((None, timed_out_htlcs))
        }
 
+       /// 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.
+       ///
+       /// 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, txdata: &TransactionData, height: u32) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
+               self.transactions_confirmed(&header.block_hash(), height, txdata)?;
+               self.update_best_block(height, header.time)
+       }
+
        /// Called by channelmanager based on chain blocks being disconnected.
        /// Returns true if we need to close the channel now due to funding transaction
        /// unconfirmation/reorg.
-       pub fn block_disconnected(&mut self, header: &BlockHeader) -> bool {
-               if self.funding_tx_confirmations > 0 {
-                       self.funding_tx_confirmations -= 1;
-                       if self.funding_tx_confirmations == UNCONF_THRESHOLD as u64 {
-                               return true;
-                       }
-               }
-               if Some(header.block_hash()) == self.funding_tx_confirmed_in {
-                       self.funding_tx_confirmations = self.minimum_depth as u64 - 1;
+       pub fn block_disconnected(&mut self, header: &BlockHeader, new_height: u32) -> bool {
+               if self.update_best_block(new_height, header.time).is_err() {
+                       return true;
                }
                false
        }
@@ -4466,8 +4485,8 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
                }
 
                self.funding_tx_confirmed_in.write(writer)?;
+               self.funding_tx_confirmation_height.write(writer)?;
                self.short_channel_id.write(writer)?;
-               self.funding_tx_confirmations.write(writer)?;
 
                self.counterparty_dust_limit_satoshis.write(writer)?;
                self.holder_dust_limit_satoshis.write(writer)?;
@@ -4636,8 +4655,8 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                };
 
                let funding_tx_confirmed_in = Readable::read(reader)?;
+               let funding_tx_confirmation_height = Readable::read(reader)?;
                let short_channel_id = Readable::read(reader)?;
-               let funding_tx_confirmations = Readable::read(reader)?;
 
                let counterparty_dust_limit_satoshis = Readable::read(reader)?;
                let holder_dust_limit_satoshis = Readable::read(reader)?;
@@ -4716,8 +4735,8 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                        last_sent_closing_fee,
 
                        funding_tx_confirmed_in,
+                       funding_tx_confirmation_height,
                        short_channel_id,
-                       funding_tx_confirmations,
 
                        counterparty_dust_limit_satoshis,
                        holder_dust_limit_satoshis,