Avoid commitment broadcast upon detected funding spend

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

diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs
index e79e50172f9f3f1c5c8a2e98d378f118e6841001..da30f86149b7b918065de56dfa821267c563f721 100644 (file)
--- a/lightning/src/chain/channelmonitor.rs
+++ b/lightning/src/chain/channelmonitor.rs
@@ -793,7 +793,10 @@ pub(crate) struct ChannelMonitorImpl<Signer: Sign> {
        // of block connection between ChannelMonitors and the ChannelManager.
        funding_spend_seen: bool,
 
+       /// Set to `Some` of the confirmed transaction spending the funding input of the channel after
+       /// reaching `ANTI_REORG_DELAY` confirmations.
        funding_spend_confirmed: Option<Txid>,
+
        confirmed_commitment_tx_counterparty_output: CommitmentTxCounterpartyOutputInfo,
        /// The set of HTLCs which have been either claimed or failed on chain and have reached
        /// the requisite confirmations on the claim/fail transaction (either ANTI_REORG_DELAY or the
@@ -3068,6 +3071,16 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
        }
 
        fn should_broadcast_holder_commitment_txn<L: Deref>(&self, logger: &L) -> bool where L::Target: Logger {
+               // There's no need to broadcast our commitment transaction if we've seen one confirmed (even
+               // with 1 confirmation) as it'll be rejected as duplicate/conflicting.
+               if self.funding_spend_confirmed.is_some() ||
+                       self.onchain_events_awaiting_threshold_conf.iter().find(|event| match event.event {
+                               OnchainEvent::FundingSpendConfirmation { .. } => true,
+                               _ => false,
+                       }).is_some()
+               {
+                       return false;
+               }
                // We need to consider all HTLCs which are:
                //  * in any unrevoked counterparty commitment transaction, as they could broadcast said
                //    transactions and we'd end up in a race, or