Merge pull request #838 from TheBlueMatt/2021-03-skip-blocks
[rust-lightning] / lightning / src / ln / channel.rs
index 1279f310d4bfdbcfd134a9b53c95674fa0dd21bf..174eed9b9185669dcc704f81d5b849d62837d641 100644 (file)
@@ -7,7 +7,6 @@
 // You may not use this file except in accordance with one or both of these
 // licenses.
 
-use bitcoin::blockdata::block::BlockHeader;
 use bitcoin::blockdata::script::{Script,Builder};
 use bitcoin::blockdata::transaction::{TxIn, TxOut, Transaction, SigHashType};
 use bitcoin::blockdata::opcodes;
@@ -3502,52 +3501,120 @@ impl<Signer: Sign> Channel<Signer> {
                self.network_sync == UpdateStatus::DisabledMarked
        }
 
-       pub fn transactions_confirmed(&mut self, block_hash: &BlockHash, height: u32, txdata: &TransactionData) -> Result<(), msgs::ErrorMessage> {
+       fn check_get_funding_locked(&mut self, height: u32) -> Option<msgs::FundingLocked> {
+               if self.funding_tx_confirmation_height == 0 {
+                       return None;
+               }
+
+               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;
+               }
+
+               if funding_tx_confirmations < self.minimum_depth as i64 {
+                       return None;
+               }
+
+               let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
+               let need_commitment_update = if non_shutdown_state == ChannelState::FundingSent as u32 {
+                       self.channel_state |= ChannelState::OurFundingLocked as u32;
+                       true
+               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::TheirFundingLocked as u32) {
+                       self.channel_state = ChannelState::ChannelFunded as u32 | (self.channel_state & MULTI_STATE_FLAGS);
+                       self.update_time_counter += 1;
+                       true
+               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurFundingLocked as u32) {
+                       // We got a reorg but not enough to trigger a force close, just ignore.
+                       false
+               } else if self.channel_state < ChannelState::ChannelFunded as u32 {
+                       panic!("Started confirming a channel in a state pre-FundingSent?: {}", self.channel_state);
+               } else {
+                       // We got a reorg but not enough to trigger a force close, just ignore.
+                       false
+               };
+
+               if need_commitment_update {
+                       if self.channel_state & (ChannelState::MonitorUpdateFailed as u32) == 0 {
+                               let next_per_commitment_point = self.holder_signer.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
+                               return Some(msgs::FundingLocked {
+                                       channel_id: self.channel_id,
+                                       next_per_commitment_point,
+                               });
+                       } else {
+                               self.monitor_pending_funding_locked = true;
+                       }
+               }
+               None
+       }
+
+       /// When a transaction is confirmed, we check whether it is or spends the funding transaction
+       /// In the first case, we store the confirmation height and calculating the short channel id.
+       /// In the second, we simply return an Err indicating we need to be force-closed now.
+       pub fn transactions_confirmed<L: Deref>(&mut self, block_hash: &BlockHash, height: u32, txdata: &TransactionData, logger: &L)
+                       -> Result<Option<msgs::FundingLocked>, msgs::ErrorMessage> where L::Target: Logger {
                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() {
-                               let funding_txo = self.get_funding_txo().unwrap();
-                               if tx.txid() == funding_txo.txid {
-                                       let txo_idx = funding_txo.index as usize;
-                                       if txo_idx >= tx.output.len() || tx.output[txo_idx].script_pubkey != self.get_funding_redeemscript().to_v0_p2wsh() ||
-                                                       tx.output[txo_idx].value != self.channel_value_satoshis {
-                                               if self.is_outbound() {
-                                                       // If we generated the funding transaction and it doesn't match what it
-                                                       // should, the client is really broken and we should just panic and
-                                                       // tell them off. That said, because hash collisions happen with high
-                                                       // probability in fuzztarget mode, if we're fuzzing we just close the
-                                                       // channel and move on.
-                                                       #[cfg(not(feature = "fuzztarget"))]
-                                                       panic!("Client called ChannelManager::funding_transaction_generated with bogus transaction!");
+               for &(index_in_block, tx) in txdata.iter() {
+                       if let Some(funding_txo) = self.get_funding_txo() {
+                               // If we haven't yet sent a funding_locked, but are in FundingSent (ignoring
+                               // whether they've sent a funding_locked or not), check if we should send one.
+                               if non_shutdown_state & !(ChannelState::TheirFundingLocked as u32) == ChannelState::FundingSent as u32 {
+                                       if tx.txid() == funding_txo.txid {
+                                               let txo_idx = funding_txo.index as usize;
+                                               if txo_idx >= tx.output.len() || tx.output[txo_idx].script_pubkey != self.get_funding_redeemscript().to_v0_p2wsh() ||
+                                                               tx.output[txo_idx].value != self.channel_value_satoshis {
+                                                       if self.is_outbound() {
+                                                               // If we generated the funding transaction and it doesn't match what it
+                                                               // should, the client is really broken and we should just panic and
+                                                               // tell them off. That said, because hash collisions happen with high
+                                                               // probability in fuzztarget mode, if we're fuzzing we just close the
+                                                               // channel and move on.
+                                                               #[cfg(not(feature = "fuzztarget"))]
+                                                               panic!("Client called ChannelManager::funding_transaction_generated with bogus transaction!");
+                                                       }
+                                                       self.channel_state = ChannelState::ShutdownComplete as u32;
+                                                       self.update_time_counter += 1;
+                                                       return Err(msgs::ErrorMessage {
+                                                               channel_id: self.channel_id(),
+                                                               data: "funding tx had wrong script/value or output index".to_owned()
+                                                       });
+                                               } else {
+                                                       if self.is_outbound() {
+                                                               for input in tx.input.iter() {
+                                                                       if input.witness.is_empty() {
+                                                                               // We generated a malleable funding transaction, implying we've
+                                                                               // just exposed ourselves to funds loss to our counterparty.
+                                                                               #[cfg(not(feature = "fuzztarget"))]
+                                                                               panic!("Client called ChannelManager::funding_transaction_generated with bogus transaction!");
+                                                                       }
+                                                               }
+                                                       }
+                                                       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"),
+                                                       }
                                                }
-                                               self.channel_state = ChannelState::ShutdownComplete as u32;
-                                               self.update_time_counter += 1;
+                                       }
+                                       // If we allow 1-conf funding, we may need to check for funding_locked here and
+                                       // send it immediately instead of waiting for an update_best_block call (which
+                                       // may have already happened for this block).
+                                       if let Some(funding_locked) = self.check_get_funding_locked(height) {
+                                               return Ok(Some(funding_locked));
+                                       }
+                               }
+                               for inp in tx.input.iter() {
+                                       if inp.previous_output == funding_txo.into_bitcoin_outpoint() {
+                                               log_trace!(logger, "Detected channel-closing tx {} spending {}:{}, closing channel {}", tx.txid(), inp.previous_output.txid, inp.previous_output.vout, log_bytes!(self.channel_id()));
                                                return Err(msgs::ErrorMessage {
                                                        channel_id: self.channel_id(),
-                                                       data: "funding tx had wrong script/value".to_owned()
+                                                       data: "Commitment or closing transaction was confirmed on chain.".to_owned()
                                                });
-                                       } else {
-                                               if self.is_outbound() {
-                                                       for input in tx.input.iter() {
-                                                               if input.witness.is_empty() {
-                                                                       // We generated a malleable funding transaction, implying we've
-                                                                       // just exposed ourselves to funds loss to our counterparty.
-                                                                       #[cfg(not(feature = "fuzztarget"))]
-                                                                       panic!("Client called ChannelManager::funding_transaction_generated with bogus transaction!");
-                                                               }
-                                                       }
-                                               }
-                                               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"),
-                                               }
                                        }
                                }
                        }
                }
-               Ok(())
+               Ok(None)
        }
 
        /// When a new block is connected, we check the height of the block against outbound holding
@@ -3577,93 +3644,37 @@ impl<Signer: Sign> Channel<Signer> {
                });
 
                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;
+
+               if let Some(funding_locked) = self.check_get_funding_locked(height) {
+                       return Ok((Some(funding_locked), timed_out_htlcs));
+               }
+
+               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 {
+                       let mut funding_tx_confirmations = height as i64 - self.funding_tx_confirmation_height as i64 + 1;
+                       if self.funding_tx_confirmation_height == 0 {
+                               // Note that check_get_funding_locked may reset funding_tx_confirmation_height to
+                               // zero if it has been reorged out, however in either case, our state flags
+                               // indicate we've already sent a funding_locked
+                               funding_tx_confirmations = 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 {
+                       // If we've sent funding_locked (or have both sent and received funding_locked), and
+                       // the funding transaction's confirmation count has dipped below minimum_depth / 2,
+                       // close the channel and hope we can get the latest state on chain (because presumably
+                       // the funding transaction is at least still in the mempool of most nodes).
+                       if 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
-                               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::TheirFundingLocked as u32) {
-                                       self.channel_state = ChannelState::ChannelFunded as u32 | (self.channel_state & MULTI_STATE_FLAGS);
-                                       self.update_time_counter += 1;
-                                       true
-                               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurFundingLocked as u32) {
-                                       // We got a reorg but not enough to trigger a force close, just update
-                                       // funding_tx_confirmed_in and return.
-                                       false
-                               } else if self.channel_state < ChannelState::ChannelFunded as u32 {
-                                       panic!("Started confirming a channel in a state pre-FundingSent?: {}", self.channel_state);
-                               } else {
-                                       // We got a reorg but not enough to trigger a force close, just update
-                                       // funding_tx_confirmed_in and return.
-                                       false
-                               };
-
-                               //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,
-                               //they can by sending two revoke_and_acks back-to-back, but not really). This appears to be
-                               //a protocol oversight, but I assume I'm just missing something.
-                               if need_commitment_update {
-                                       if self.channel_state & (ChannelState::MonitorUpdateFailed as u32) == 0 {
-                                               let next_per_commitment_point = self.holder_signer.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
-                                               return Ok((Some(msgs::FundingLocked {
-                                                       channel_id: self.channel_id,
-                                                       next_per_commitment_point,
-                                               }), timed_out_htlcs));
-                                       } else {
-                                               self.monitor_pending_funding_locked = true;
-                                               return Ok((None, timed_out_htlcs));
-                                       }
-                               }
-                       }
                }
 
                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, new_height: u32) -> bool {
-               if self.update_best_block(new_height, header.time).is_err() {
-                       return true;
-               }
-               false
-       }
-
        // Methods to get unprompted messages to send to the remote end (or where we already returned
        // something in the handler for the message that prompted this message):