Merge pull request #197 from TheBlueMatt/master

[rust-lightning] / src / ln / channelmonitor.rs

diff --git a/src/ln/channelmonitor.rs b/src/ln/channelmonitor.rs
index acd63da79e1bd63b511bfc7ec49ed29bb3dbcebb..4b72a3cb69d1c3436048d050c649c3ee1fae350b 100644 (file)
--- a/src/ln/channelmonitor.rs
+++ b/src/ln/channelmonitor.rs
@@ -1,8 +1,10 @@
 //! The logic to monitor for on-chain transactions and create the relevant claim responses lives
 //! here.
+//!
 //! ChannelMonitor objects are generated by ChannelManager in response to relevant
 //! messages/actions, and MUST be persisted to disk (and, preferably, remotely) before progress can
 //! be made in responding to certain messages, see ManyChannelMonitor for more.
+//!
 //! Note that ChannelMonitors are an important part of the lightning trust model and a copy of the
 //! latest ChannelMonitor must always be actively monitoring for chain updates (and no out-of-date
 //! ChannelMonitors should do so). Thus, if you're building rust-lightning into an HSM or other
@@ -40,6 +42,7 @@ use std::{hash,cmp};
 pub enum ChannelMonitorUpdateErr {
        /// Used to indicate a temporary failure (eg connection to a watchtower failed, but is expected
        /// to succeed at some point in the future).
+       ///
        /// Such a failure will "freeze" a channel, preventing us from revoking old states or
        /// submitting new commitment transactions to the remote party.
        /// ChannelManager::test_restore_channel_monitor can be used to retry the update(s) and restore
@@ -55,12 +58,14 @@ pub enum ChannelMonitorUpdateErr {
 /// them. Generally should be implemented by keeping a local SimpleManyChannelMonitor and passing
 /// events to it, while also taking any add_update_monitor events and passing them to some remote
 /// server(s).
+///
 /// Note that any updates to a channel's monitor *must* be applied to each instance of the
 /// channel's monitor everywhere (including remote watchtowers) *before* this function returns. If
 /// an update occurs and a remote watchtower is left with old state, it may broadcast transactions
 /// which we have revoked, allowing our counterparty to claim all funds in the channel!
 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.
@@ -69,10 +74,13 @@ pub trait ManyChannelMonitor: Send + Sync {
 
 /// A simple implementation of a ManyChannelMonitor and ChainListener. Can be used to create a
 /// watchtower or watch our own channels.
+///
 /// Note that you must provide your own key by which to refer to channels.
+///
 /// If you're accepting remote monitors (ie are implementing a watchtower), you must verify that
 /// users cannot overwrite a given channel by providing a duplicate key. ie you should probably
 /// index by a PublicKey which is required to sign any updates.
+///
 /// If you're using this for local monitoring of your own channels, you probably want to use
 /// `OutPoint` as the key, which will give you a ManyChannelMonitor implementation.
 pub struct SimpleManyChannelMonitor<Key> {
@@ -180,6 +188,7 @@ const MIN_SERIALIZATION_VERSION: u8 = 1;
 
 /// A ChannelMonitor handles chain events (blocks connected and disconnected) and generates
 /// on-chain transactions to ensure no loss of funds occurs.
+///
 /// You MUST ensure that no ChannelMonitors for a given channel anywhere contain out-of-date
 /// information and are actively monitoring the chain.
 pub struct ChannelMonitor {
@@ -1002,7 +1011,9 @@ impl ChannelMonitor {
 
        /// Attempst to claim a remote HTLC-Success/HTLC-Timeout s outputs using the revocation key
        fn check_spend_remote_htlc(&self, tx: &Transaction, commitment_number: u64) -> Option<Transaction> {
-               let htlc_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
+               if tx.input.len() != 1 || tx.output.len() != 1 {
+                       return None;
+               }
 
                macro_rules! ignore_error {
                        ( $thing : expr ) => {
@@ -1030,6 +1041,7 @@ impl ChannelMonitor {
                };
                let redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.their_to_self_delay.unwrap(), &delayed_key);
                let revokeable_p2wsh = redeemscript.to_v0_p2wsh();
+               let htlc_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
 
                let mut inputs = Vec::new();
                let mut amount = 0;