From f1c88859af74b70389325971d3627e4dd268f8a1 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Mon, 20 Jan 2020 22:05:29 -0500 Subject: [PATCH] Track the full list of outpoints a chanmon wants monitoring for. Upon deserialization/reload we need to be able to register each outpoint which spends the commitment txo which a channelmonitor believes to be on chain. While our other internal tracking is likely sufficient to regenerate these, its much easier to simply track all outpouts we've ever generated, so we do that here. --- lightning/src/ln/channelmonitor.rs | 58 +++++++++++++++++++++++++++--- 1 file changed, 54 insertions(+), 4 deletions(-) diff --git a/lightning/src/ln/channelmonitor.rs b/lightning/src/ln/channelmonitor.rs index b08b44569..c35c31717 100644 --- a/lightning/src/ln/channelmonitor.rs +++ b/lightning/src/ln/channelmonitor.rs @@ -117,9 +117,13 @@ pub struct HTLCUpdate { pub trait ManyChannelMonitor: Send + Sync { /// Adds or updates a monitor for the given `funding_txo`. /// - /// Implementor must also ensure that the funding_txo outpoint is registered with any relevant - /// ChainWatchInterfaces such that the provided monitor receives block_connected callbacks with - /// any spends of it. + /// Implementer must also ensure that the funding_txo txid *and* outpoint are registered with + /// any relevant ChainWatchInterfaces such that the provided monitor receives block_connected + /// callbacks with the funding transaction, or any spends of it. + /// + /// Further, the implementer must also ensure that each output returned in + /// monitor.get_watch_outputs() is registered to ensure that the provided monitor learns about + /// any spends of any of the outputs. fn add_update_monitor(&self, funding_txo: OutPoint, monitor: ChannelMonitor) -> Result<(), ChannelMonitorUpdateErr>; /// Used by ChannelManager to get list of HTLC resolved onchain and which needed to be updated @@ -259,6 +263,11 @@ impl SimpleManyChannelMonitor self.chain_monitor.watch_all_txn(); } } + for (txid, outputs) in monitor.get_watch_outputs().iter() { + for (idx, script) in outputs.iter().enumerate() { + self.chain_monitor.install_watch_outpoint((*txid, idx as u32), script); + } + } monitors.insert(key, monitor); Ok(()) } @@ -642,6 +651,12 @@ pub struct ChannelMonitor { // actions when we receive a block with given height. Actions depend on OnchainEvent type. onchain_events_waiting_threshold_conf: HashMap>, + // If we get serialized out and re-read, we need to make sure that the chain monitoring + // interface knows about the TXOs that we want to be notified of spends of. We could probably + // be smart and derive them from the above storage fields, but its much simpler and more + // Obviously Correct (tm) if we just keep track of them explicitly. + watch_outputs: HashMap>, + // We simply modify last_block_hash in Channel's block_connected so that serialization is // consistent but hopefully the users' copy handles block_connected in a consistent way. // (we do *not*, however, update them in insert_combine to ensure any local user copies keep @@ -712,7 +727,8 @@ impl PartialEq for ChannelMonitor { self.to_remote_rescue != other.to_remote_rescue || self.pending_claim_requests != other.pending_claim_requests || self.claimable_outpoints != other.claimable_outpoints || - self.onchain_events_waiting_threshold_conf != other.onchain_events_waiting_threshold_conf + self.onchain_events_waiting_threshold_conf != other.onchain_events_waiting_threshold_conf || + self.watch_outputs != other.watch_outputs { false } else { @@ -769,6 +785,7 @@ impl ChannelMonitor { claimable_outpoints: HashMap::new(), onchain_events_waiting_threshold_conf: HashMap::new(), + watch_outputs: HashMap::new(), last_block_hash: Default::default(), secp_ctx: Secp256k1::new(), @@ -1103,6 +1120,12 @@ impl ChannelMonitor { } } + /// Gets a list of txids, with their output scripts (in the order they appear in the + /// transaction), which we must learn about spends of via block_connected(). + pub fn get_watch_outputs(&self) -> &HashMap> { + &self.watch_outputs + } + /// Gets the sets of all outpoints which this ChannelMonitor expects to hear about spends of. /// Generally useful when deserializing as during normal operation the return values of /// block_connected are sufficient to ensure all relevant outpoints are being monitored (note @@ -1331,6 +1354,15 @@ impl ChannelMonitor { } } + (self.watch_outputs.len() as u64).write(writer)?; + for (txid, output_scripts) in self.watch_outputs.iter() { + txid.write(writer)?; + (output_scripts.len() as u64).write(writer)?; + for script in output_scripts.iter() { + script.write(writer)?; + } + } + Ok(()) } @@ -2561,6 +2593,9 @@ impl ChannelMonitor { } } self.last_block_hash = block_hash.clone(); + for &(ref txid, ref output_scripts) in watch_outputs.iter() { + self.watch_outputs.insert(txid.clone(), output_scripts.iter().map(|o| o.script_pubkey.clone()).collect()); + } (watch_outputs, spendable_outputs, htlc_updated) } @@ -3212,6 +3247,20 @@ impl ReadableArgs> for (Sha256dHash, ChannelM onchain_events_waiting_threshold_conf.insert(height_target, events); } + let watch_outputs_len: u64 = Readable::read(reader)?; + let mut watch_outputs = HashMap::with_capacity(cmp::min(watch_outputs_len as usize, MAX_ALLOC_SIZE / (32 + 3*8))); + for _ in 0..watch_outputs_len { + let txid = Readable::read(reader)?; + let outputs_len: u64 = Readable::read(reader)?; + let mut outputs = Vec::with_capacity(cmp::min(outputs_len as usize, MAX_ALLOC_SIZE / 3*8)); + for _ in 0..outputs_len { + outputs.push(Readable::read(reader)?); + } + if let Some(_) = watch_outputs.insert(txid, outputs) { + return Err(DecodeError::InvalidValue); + } + } + Ok((last_block_hash.clone(), ChannelMonitor { commitment_transaction_number_obscure_factor, @@ -3244,6 +3293,7 @@ impl ReadableArgs> for (Sha256dHash, ChannelM claimable_outpoints, onchain_events_waiting_threshold_conf, + watch_outputs, last_block_hash, secp_ctx, -- 2.39.5