send warning when we receive a old commitment transaction

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

diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index 1cb7a689a21a1b710413e93afbba8e1881d48e90..8d0f3c5e6d9a051b4aa21230dc9cfbe58c1164d6 100644 (file)
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -3737,6 +3737,15 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                }
 
+               // Before we change the state of the channel, we check if the peer is sending a very old
+               // commitment transaction number, if yes we send a warning message.
+               let our_commitment_transaction = INITIAL_COMMITMENT_NUMBER - self.cur_holder_commitment_transaction_number - 1;
+               if  msg.next_remote_commitment_number + 1 < our_commitment_transaction {
+                       return Err(
+                               ChannelError::Warn(format!("Peer attempted to reestablish channel with a very old local commitment transaction: {} (received) vs {} (expected)", msg.next_remote_commitment_number, our_commitment_transaction))
+                       );
+               }
+
                // Go ahead and unmark PeerDisconnected as various calls we may make check for it (and all
                // remaining cases either succeed or ErrorMessage-fail).
                self.channel_state &= !(ChannelState::PeerDisconnected as u32);