commit 2927478192e40fd6966af17654471ebfb9051bba
parent e7ab9e4054d37c95cd57ad051d6d8249cc7ddccf
Author: ThomasV <thomasv@electrum.org>
Date: Tue, 25 Feb 2020 12:35:07 +0100
lnpeer: closing fee negociation:
- use fee_rate from config
- set upper bound on fee
- add test_close to test_lnpeer
Diffstat:
4 files changed, 44 insertions(+), 7 deletions(-)
diff --git a/electrum/lnchannel.py b/electrum/lnchannel.py
@@ -743,6 +743,9 @@ class Channel(Logger):
def pending_local_fee(self):
return self.constraints.capacity - sum(x.value for x in self.get_next_commitment(LOCAL).outputs())
+ def get_latest_fee(self, subject):
+ return self.constraints.capacity - sum(x.value for x in self.get_latest_commitment(subject).outputs())
+
def update_fee(self, feerate: int, from_us: bool):
# feerate uses sat/kw
if self.constraints.is_initiator != from_us:
diff --git a/electrum/lnpeer.py b/electrum/lnpeer.py
@@ -1381,20 +1381,33 @@ class Peer(Logger):
while len(chan.hm.htlcs(LOCAL)) + len(chan.hm.htlcs(REMOTE)) > 0:
self.logger.info(f'(chan: {chan.short_channel_id}) waiting for htlcs to settle...')
await asyncio.sleep(1)
- our_fee = chan.pending_local_fee()
- scriptpubkey = bfh(bitcoin.address_to_script(chan.sweep_address))
+ their_scriptpubkey = payload['scriptpubkey']
+ our_scriptpubkey = bfh(bitcoin.address_to_script(chan.sweep_address))
+ # estimate fee of closing tx
+ our_sig, closing_tx = chan.make_closing_tx(our_scriptpubkey, their_scriptpubkey, fee_sat=0)
+ fee_rate = self.network.config.fee_per_kb()
+ our_fee = fee_rate * closing_tx.estimated_size() // 1000
+ # BOLT2: The sending node MUST set fee less than or equal to the base fee of the final ctx
+ max_fee = chan.get_latest_fee(LOCAL if is_local else REMOTE)
+ our_fee = min(our_fee, max_fee)
# negotiate fee
while True:
- our_sig, closing_tx = chan.make_closing_tx(scriptpubkey, payload['scriptpubkey'], fee_sat=our_fee)
+ self.logger.info(f'sending closing_signed {our_fee}')
+ our_sig, closing_tx = chan.make_closing_tx(our_scriptpubkey, their_scriptpubkey, fee_sat=our_fee)
self.send_message('closing_signed', channel_id=chan.channel_id, fee_satoshis=our_fee, signature=our_sig)
# FIXME: the remote SHOULD send closing_signed, but some don't.
cs_payload = await self.wait_for_message('closing_signed', chan.channel_id)
their_fee = int.from_bytes(cs_payload['fee_satoshis'], 'big')
their_sig = cs_payload['signature']
- if our_fee == their_fee:
+ # TODO: verify their sig
+ if their_fee > max_fee:
+ raise Exception(f'the proposed fee exceeds the base fee of the latest commitment transaction {is_local, their_fee, max_fee}')
+ # Agree if difference is lower or equal to one (see below)
+ if abs(our_fee - their_fee) < 2:
break
- # TODO: negotiate better
- our_fee = their_fee
+ # BOLT2: receiver MUST propose a value "strictly between" the received fee_satoshis and its previously-sent fee_satoshis.
+ our_fee = (our_fee + (1 if our_fee < their_fee else -1) + their_fee) // 2
+
# add signatures
closing_tx.add_signature_to_txin(txin_idx=0,
signing_pubkey=chan.config[LOCAL].multisig_key.pubkey.hex(),
@@ -1403,5 +1416,5 @@ class Peer(Logger):
signing_pubkey=chan.config[REMOTE].multisig_key.pubkey.hex(),
sig=bh2u(der_sig_from_sig_string(their_sig) + b'\x01'))
# broadcast
- await self.network.broadcast_transaction(closing_tx)
+ await self.network.try_broadcasting(closing_tx, 'closing')
return closing_tx.txid()
diff --git a/electrum/tests/test_lnchannel.py b/electrum/tests/test_lnchannel.py
@@ -165,6 +165,9 @@ def create_test_channels(feerate=6000, local=None, remote=None):
alice.hm.channel_open_finished()
bob.hm.channel_open_finished()
+ # TODO: sweep_address in lnchannel.py should use static_remotekey
+ alice.sweep_address = bitcoin.pubkey_to_address('p2wpkh', alice.config[LOCAL].payment_basepoint.pubkey.hex())
+ bob.sweep_address = bitcoin.pubkey_to_address('p2wpkh', bob.config[LOCAL].payment_basepoint.pubkey.hex())
return alice, bob
class TestFee(ElectrumTestCase):
diff --git a/electrum/tests/test_lnpeer.py b/electrum/tests/test_lnpeer.py
@@ -283,6 +283,24 @@ class TestPeer(ElectrumTestCase):
with self.assertRaises(concurrent.futures.CancelledError):
run(f())
+ def test_close(self):
+ alice_channel, bob_channel = create_test_channels()
+ p1, p2, w1, w2, _q1, _q2 = self.prepare_peers(alice_channel, bob_channel)
+ w1.network.config.set_key('dynamic_fees', False)
+ w2.network.config.set_key('dynamic_fees', False)
+ w1.network.config.set_key('fee_per_kb', 5000)
+ w2.network.config.set_key('fee_per_kb', 1000)
+ async def pay():
+ await asyncio.wait_for(p1.initialized, 1)
+ await asyncio.wait_for(p2.initialized, 1)
+ await p1.close_channel(alice_channel.channel_id)
+ gath.cancel()
+ gath = asyncio.gather(pay(), p1._message_loop(), p2._message_loop())
+ async def f():
+ await gath
+ with self.assertRaises(concurrent.futures.CancelledError):
+ run(f())
+
def test_channel_usage_after_closing(self):
alice_channel, bob_channel = create_test_channels()
p1, p2, w1, w2, q1, q2 = self.prepare_peers(alice_channel, bob_channel)
