commit c0a1af2032117ba81e1eac4c1d67e51900b2f767
parent 5bc74772a24a2f911276f4a19fc0749241d4bff1
Author: ThomasV <thomasv@electrum.org>
Date: Thu, 22 Nov 2018 16:18:28 +0100
fix channel closure:
- add 'CLOSING' state
- wait until channel has no inflight HTLC
- end fee negocitation when both parties agree on the fee
(previously code ended it only when the other party had broadcast)
- broadcast the closing transaction
Diffstat:
2 files changed, 28 insertions(+), 19 deletions(-)
diff --git a/electrum/lnbase.py b/electrum/lnbase.py
@@ -1147,8 +1147,6 @@ class Peer(PrintError):
@log_exceptions
async def close_channel(self, chan_id: bytes):
chan = self.channels[chan_id]
- if len(chan.htlcs(LOCAL, only_pending=True)) > 0:
- raise Exception('Can\'t co-operatively close channel with payments ongoing (pending HTLCs). Please wait, or force-close the channel.')
self.shutdown_received[chan_id] = asyncio.Future()
self.send_shutdown(chan)
payload = await self.shutdown_received[chan_id]
@@ -1176,16 +1174,27 @@ class Peer(PrintError):
@log_exceptions
async def _shutdown(self, chan: Channel, payload):
+ # set state so that we stop accepting HTLCs
+ chan.set_state('CLOSING')
+ while len(chan.htlcs(LOCAL, only_pending=True)) > 0:
+ await asyncio.sleep(1)
+ our_fee = chan.pending_local_fee()
scriptpubkey = bfh(bitcoin.address_to_script(chan.sweep_address))
- signature, fee, txid = chan.make_closing_tx(scriptpubkey, payload['scriptpubkey'])
- self.send_message('closing_signed', channel_id=chan.channel_id, fee_satoshis=fee, signature=signature)
- while chan.get_state() != 'CLOSED':
- try:
- closing_signed = await asyncio.wait_for(self.closing_signed[chan.channel_id].get(), 1)
- except asyncio.TimeoutError:
- pass
- else:
- fee = int.from_bytes(closing_signed['fee_satoshis'], 'big')
- signature, _, txid = chan.make_closing_tx(scriptpubkey, payload['scriptpubkey'], fee_sat=fee)
- self.send_message('closing_signed', channel_id=chan.channel_id, fee_satoshis=fee, signature=signature)
- return txid
+ # negociate fee
+ while True:
+ our_sig, closing_tx = chan.make_closing_tx(scriptpubkey, payload['scriptpubkey'], fee_sat=our_fee)
+ self.send_message('closing_signed', channel_id=chan.channel_id, fee_satoshis=our_fee, signature=our_sig)
+ cs_payload = await asyncio.wait_for(self.closing_signed[chan.channel_id].get(), 1)
+ their_fee = int.from_bytes(cs_payload['fee_satoshis'], 'big')
+ their_sig = cs_payload['signature']
+ if our_fee == their_fee:
+ break
+ # TODO: negociate better
+ our_fee = their_fee
+ # add their signature
+ i = chan.get_local_index()
+ closing_tx.add_signature_to_txin(0, i, bh2u(our_sig))
+ closing_tx.add_signature_to_txin(0, 1-i, bh2u(their_sig))
+ # broadcast
+ await self.network.broadcast_transaction(closing_tx)
+ return closing_tx.txid()
diff --git a/electrum/lnchan.py b/electrum/lnchan.py
@@ -824,12 +824,12 @@ class Channel(PrintError):
),
htlcs=htlcs)
+ def get_local_index(self):
+ return int(self.config[LOCAL].multisig_key.pubkey < self.config[REMOTE].multisig_key.pubkey)
+
def make_closing_tx(self, local_script: bytes, remote_script: bytes,
- fee_sat: Optional[int]=None) -> Tuple[bytes, int, str]:
+ fee_sat: int) -> Tuple[bytes, int, str]:
""" cooperative close """
- if fee_sat is None:
- fee_sat = self.pending_local_fee()
-
_, outputs = make_commitment_outputs({
LOCAL: fee_sat * 1000 if self.constraints.is_initiator else 0,
REMOTE: fee_sat * 1000 if not self.constraints.is_initiator else 0,
@@ -849,7 +849,7 @@ class Channel(PrintError):
der_sig = bfh(closing_tx.sign_txin(0, self.config[LOCAL].multisig_key.privkey))
sig = ecc.sig_string_from_der_sig(der_sig[:-1])
- return sig, fee_sat, closing_tx.txid()
+ return sig, closing_tx
def force_close_tx(self):
# local_commitment always gives back the next expected local_commitment,
