tlnpeer: reestablish_channel - always replay unacked local updates - electrum - Electrum Bitcoin wallet
HTML git clone https://git.parazyd.org/electrum
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---
DIR commit 4fc9f243f7d1c957770589582261389a6a74b9ee
DIR parent 98a1c9268a2ebe569d454014699df1c14be671f5
HTML Author: SomberNight <somber.night@protonmail.com>
Date: Mon, 12 Aug 2019 17:06:05 +0200
lnpeer: reestablish_channel - always replay unacked local updates
Even if we haven't signed them yet (did not send commitment_signed).
Alternatively, if they are not yet signed, we could discard them here,
like we do already for remote updates above (chan.hm.discard_unsigned_remote_updates).
One of these two options must be done, and before this commit we were not doing either.
Diffstat:
M electrum/lnpeer.py | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
---
DIR diff --git a/electrum/lnpeer.py b/electrum/lnpeer.py
t@@ -748,20 +748,24 @@ class Peer(Logger):
raise RemoteMisbehaving(f"channel reestablish: their_next_local_ctn < 0")
if their_oldest_unrevoked_remote_ctn < 0:
raise RemoteMisbehaving(f"channel reestablish: their_oldest_unrevoked_remote_ctn < 0")
+ # Replay un-acked local updates (including commitment_signed) byte-for-byte.
+ # If we have sent them a commitment signature that they "lost" (due to disconnect),
+ # we need to make sure we replay the same local updates, as otherwise they could
+ # end up with two (or more) signed valid commitment transactions at the same ctn.
+ # Multiple valid ctxs at the same ctn is a major headache for pre-signing spending txns,
+ # e.g. for watchtowers, hence we must ensure these ctxs coincide.
+ # We replay the local updates even if they were not yet committed.
+ for raw_upd_msg in chan.hm.get_unacked_local_updates():
+ self.transport.send_bytes(raw_upd_msg)
should_close_we_are_ahead = False
should_close_they_are_ahead = False
# compare remote ctns
if next_remote_ctn != their_next_local_ctn:
if their_next_local_ctn == latest_remote_ctn and chan.hm.is_revack_pending(REMOTE):
- # Replay un-acked local updates (including commitment_signed) byte-for-byte.
- # If we have sent them a commitment signature that they "lost" (due to disconnect),
- # we need to make sure we replay the same local updates, as otherwise they could
- # end up with two (or more) signed valid commitment transactions at the same ctn.
- # Multiple valid ctxs at the same ctn is a major headache for pre-signing spending txns,
- # e.g. for watchtowers, hence we must ensure these ctxs coincide.
- for raw_upd_msg in chan.hm.get_unacked_local_updates():
- self.transport.send_bytes(raw_upd_msg)
+ # We replayed the local updates (see above), which should have contained a commitment_signed
+ # (due to is_revack_pending being true), and this should have remedied this situation.
+ pass
else:
self.logger.warning(f"channel_reestablish: expected remote ctn {next_remote_ctn}, got {their_next_local_ctn}")
if their_next_local_ctn < next_remote_ctn: