From f403735191e51455b6741b019121bd571cb1cce4 Mon Sep 17 00:00:00 2001 From: SomberNight Date: Thu, 29 Aug 2019 12:37:25 +0200 Subject: [PATCH] lnpeer: reestablish_channel - don't replay unacked msgs they alrdy have e.g. Alice sends upd1, upd2, upd3, commitment_signed, upd4, upd5. Bob receives all of these; and sends a revoke_and_ack but there is a disconnect before Alice receives the revoke_and_ack. During reestablish, if Bob claims to have received the commitment_signed, Alice must not replay the msgs before that; but she should replay upd4 and upd5. --- electrum/lnpeer.py | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/electrum/lnpeer.py b/electrum/lnpeer.py index e3d5a5c44..fdd194127 100644 --- a/electrum/lnpeer.py +++ b/electrum/lnpeer.py @@ -141,7 +141,7 @@ class Peer(Logger): asyncio.ensure_future(execution_result) def on_error(self, payload): - self.logger.info(f"error {payload['data'].decode('ascii')}") + self.logger.info(f"on_error: {payload['data'].decode('ascii')}") chan_id = payload.get("channel_id") for d in [ self.channel_accepted, self.funding_signed, self.funding_created, self.channel_reestablished, @@ -753,10 +753,16 @@ class Peer(Logger): channel_id=chan_id, next_local_commitment_number=next_local_ctn, next_remote_revocation_number=oldest_unrevoked_remote_ctn) + self.logger.info(f'channel_reestablish: sent channel_reestablish with ' + f'(next_local_ctn={next_local_ctn}, ' + f'oldest_unrevoked_remote_ctn={oldest_unrevoked_remote_ctn})') channel_reestablish_msg = await self.channel_reestablished[chan_id].get() their_next_local_ctn = int.from_bytes(channel_reestablish_msg["next_local_commitment_number"], 'big') their_oldest_unrevoked_remote_ctn = int.from_bytes(channel_reestablish_msg["next_remote_revocation_number"], 'big') + self.logger.info(f'channel_reestablish: received channel_reestablish with ' + f'(their_next_local_ctn={their_next_local_ctn}, ' + f'their_oldest_unrevoked_remote_ctn={their_oldest_unrevoked_remote_ctn})') their_local_pcp = channel_reestablish_msg.get("my_current_per_commitment_point") their_claim_of_our_last_per_commitment_secret = channel_reestablish_msg.get("your_last_per_commitment_secret") # sanity checks of received values @@ -772,10 +778,16 @@ class Peer(Logger): # e.g. for watchtowers, hence we must ensure these ctxs coincide. # We replay the local updates even if they were not yet committed. unacked = chan.hm.get_unacked_local_updates() - self.logger.info(f'replaying {len(unacked)} unacked messages') + n_replayed_msgs = 0 for ctn, messages in unacked.items(): + if ctn < their_next_local_ctn: + # They claim to have received these messages and the corresponding + # commitment_signed, hence we must not replay them. + continue for raw_upd_msg in messages: self.transport.send_bytes(raw_upd_msg) + n_replayed_msgs += 1 + self.logger.info(f'channel_reestablish: replayed {n_replayed_msgs} unacked messages') should_close_we_are_ahead = False should_close_they_are_ahead = False