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lnpeer.reestablish_chan: enforce order of replaying commitsig/revack

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When replaying messages during channel-reestablishment,
previously we first resent all update messages, along with potential commitment_signed messages,
and then we potentially resent a single revoke_and_ack.

This can result in incorrect behaviour in case both a commitment_signed and a revoke_and_ack needs to be resent.
When replaying messages, the relative order of commitment_signed and revoke_and_messages needs to be preserved.
(the order of updates (htlc/fee) in relation to the revack messages does not matter)

implements https://github.com/lightning/bolts/pull/810

The logic here is somewhat based on what c-lightning does:
01e5f1886e/channeld/channeld.c (L3059)
This commit is contained in:
SomberNight
2022-05-24 23:49:58 +02:00
parent 7abc7c720f
commit ef4477a930
3 changed files with 187 additions and 24 deletions
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144
electrum/tests/test_lnpeer.py
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@@ -35,7 +35,7 @@ from electrum import lnmsg
from electrum.logging import console_stderr_handler, Logger
from electrum.lnworker import PaymentInfo, RECEIVED
from electrum.lnonion import OnionFailureCode
from electrum.lnutil import derive_payment_secret_from_payment_preimage
from electrum.lnutil import derive_payment_secret_from_payment_preimage, UpdateAddHtlc
from electrum.lnutil import LOCAL, REMOTE
from electrum.invoices import PR_PAID, PR_UNPAID
from electrum.interface import GracefulDisconnect
@@ -256,7 +256,7 @@ class MockLNWallet(Logger, NetworkRetryManager[LNPeerAddr]):
class MockTransport:
def __init__(self, name):
self.queue = asyncio.Queue()
self.queue = asyncio.Queue() # incoming messages
self._name = name
self.peer_addr = None
@@ -265,7 +265,11 @@ class MockTransport:
async def read_messages(self):
while True:
yield await self.queue.get()
data = await self.queue.get()
if isinstance(data, asyncio.Event): # to artificially delay messages
await data.wait()
continue
yield data
class NoFeaturesTransport(MockTransport):
"""
@@ -382,8 +386,14 @@ class TestPeer(TestCaseForTestnet):
super().tearDown()
def prepare_peers(self, alice_channel: Channel, bob_channel: Channel):
k1, k2 = keypair(), keypair()
def prepare_peers(
self, alice_channel: Channel, bob_channel: Channel,
*, k1: Keypair = None, k2: Keypair = None,
):
if k1 is None:
k1 = keypair()
if k2 is None:
k2 = keypair()
alice_channel.node_id = k2.pubkey
bob_channel.node_id = k1.pubkey
t1, t2 = transport_pair(k1, k2, alice_channel.name, bob_channel.name)
@@ -557,6 +567,130 @@ class TestPeer(TestCaseForTestnet):
self.assertEqual(alice_channel_0.peer_state, PeerState.BAD)
self.assertEqual(bob_channel._state, ChannelState.FORCE_CLOSING)
@staticmethod
def _send_fake_htlc(peer: Peer, chan: Channel) -> UpdateAddHtlc:
htlc = UpdateAddHtlc(amount_msat=10000, payment_hash=os.urandom(32), cltv_expiry=999, timestamp=1)
htlc = chan.add_htlc(htlc)
peer.send_message(
"update_add_htlc",
channel_id=chan.channel_id,
id=htlc.htlc_id,
cltv_expiry=htlc.cltv_expiry,
amount_msat=htlc.amount_msat,
payment_hash=htlc.payment_hash,
onion_routing_packet=1366 * b"0",
)
return htlc
def test_reestablish_replay_messages_rev_then_sig(self):
"""
See https://github.com/lightning/bolts/pull/810#issue-728299277
Rev then Sig
A B
<---add-----
----add---->
<---sig-----
----rev----x
----sig----x
A needs to retransmit:
----rev--> (note that 'add' can be first too)
----add-->
----sig-->
"""
chan_AB, chan_BA = create_test_channels()
k1, k2 = keypair(), keypair()
# note: we don't start peer.htlc_switch() so that the fake htlcs are left alone.
async def f():
p1, p2, w1, w2, _q1, _q2 = self.prepare_peers(chan_AB, chan_BA, k1=k1, k2=k2)
async with OldTaskGroup() as group:
await group.spawn(p1._message_loop())
await group.spawn(p2._message_loop())
await p1.initialized
await p2.initialized
self._send_fake_htlc(p2, chan_BA)
self._send_fake_htlc(p1, chan_AB)
p2.transport.queue.put_nowait(asyncio.Event()) # break Bob's incoming pipe
self.assertTrue(p2.maybe_send_commitment(chan_BA))
await p1.received_commitsig_event.wait()
await group.cancel_remaining()
# simulating disconnection. recreate transports.
p1, p2, w1, w2, _q1, _q2 = self.prepare_peers(chan_AB, chan_BA, k1=k1, k2=k2)
for chan in (chan_AB, chan_BA):
chan.peer_state = PeerState.DISCONNECTED
async with OldTaskGroup() as group:
await group.spawn(p1._message_loop())
await group.spawn(p2._message_loop())
with self.assertLogs('electrum', level='INFO') as logs:
async with OldTaskGroup() as group2:
await group2.spawn(p1.reestablish_channel(chan_AB))
await group2.spawn(p2.reestablish_channel(chan_BA))
self.assertTrue(any(("alice->bob" in msg and
"replaying a revoke_and_ack first" in msg) for msg in logs.output))
self.assertTrue(any(("alice->bob" in msg and
"replayed 2 unacked messages. ['update_add_htlc', 'commitment_signed']" in msg) for msg in logs.output))
self.assertEqual(chan_AB.peer_state, PeerState.GOOD)
self.assertEqual(chan_BA.peer_state, PeerState.GOOD)
raise SuccessfulTest()
with self.assertRaises(SuccessfulTest):
run(f())
def test_reestablish_replay_messages_sig_then_rev(self):
"""
See https://github.com/lightning/bolts/pull/810#issue-728299277
Sig then Rev
A B
<---add-----
----add---->
----sig----x
<---sig-----
----rev----x
A needs to retransmit:
----add-->
----sig-->
----rev-->
"""
chan_AB, chan_BA = create_test_channels()
k1, k2 = keypair(), keypair()
# note: we don't start peer.htlc_switch() so that the fake htlcs are left alone.
async def f():
p1, p2, w1, w2, _q1, _q2 = self.prepare_peers(chan_AB, chan_BA, k1=k1, k2=k2)
async with OldTaskGroup() as group:
await group.spawn(p1._message_loop())
await group.spawn(p2._message_loop())
await p1.initialized
await p2.initialized
self._send_fake_htlc(p2, chan_BA)
self._send_fake_htlc(p1, chan_AB)
p2.transport.queue.put_nowait(asyncio.Event()) # break Bob's incoming pipe
self.assertTrue(p1.maybe_send_commitment(chan_AB))
self.assertTrue(p2.maybe_send_commitment(chan_BA))
await p1.received_commitsig_event.wait()
await group.cancel_remaining()
# simulating disconnection. recreate transports.
p1, p2, w1, w2, _q1, _q2 = self.prepare_peers(chan_AB, chan_BA, k1=k1, k2=k2)
for chan in (chan_AB, chan_BA):
chan.peer_state = PeerState.DISCONNECTED
async with OldTaskGroup() as group:
await group.spawn(p1._message_loop())
await group.spawn(p2._message_loop())
with self.assertLogs('electrum', level='INFO') as logs:
async with OldTaskGroup() as group2:
await group2.spawn(p1.reestablish_channel(chan_AB))
await group2.spawn(p2.reestablish_channel(chan_BA))
self.assertTrue(any(("alice->bob" in msg and
"replaying a revoke_and_ack last" in msg) for msg in logs.output))
self.assertTrue(any(("alice->bob" in msg and
"replayed 2 unacked messages. ['update_add_htlc', 'commitment_signed']" in msg) for msg in logs.output))
self.assertEqual(chan_AB.peer_state, PeerState.GOOD)
self.assertEqual(chan_BA.peer_state, PeerState.GOOD)
raise SuccessfulTest()
with self.assertRaises(SuccessfulTest):
run(f())
@needs_test_with_all_chacha20_implementations
def test_payment(self):
"""Alice pays Bob a single HTLC via direct channel."""