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lnchannel: apply stricter max_htlc_value_in_flight rules for receiving

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Otherwise we create invoices that eclair cannot route to us
This commit is contained in:
ThomasV
2025-05-20 12:11:20 +02:00
parent 713a20e309
commit b432a1406a
2 changed files with 23 additions and 6 deletions
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10
electrum/lnchannel.py
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@@ -1150,7 +1150,15 @@ class Channel(AbstractChannel):
# check "max_htlc_value_in_flight_msat"
ctn = self.get_next_ctn(htlc_receiver)
current_htlc_sum = htlcsum(self.hm.htlcs_by_direction(htlc_receiver, direction=RECEIVED, ctn=ctn).values())
return self.config[htlc_receiver].max_htlc_value_in_flight_msat - current_htlc_sum
max_inflight = self.config[htlc_receiver].max_htlc_value_in_flight_msat
if htlc_receiver == LOCAL:
# in order to send, eclair applies both local and remote max values
# https://github.com/ACINQ/eclair/blob/9b0c00a2a28d3ba6c7f3d01fbd2d8704ebbdc75d/eclair-core/src/main/scala/fr/acinq/eclair/channel/Commitments.scala#L503
max_inflight = min(
self.config[LOCAL].max_htlc_value_in_flight_msat,
self.config[REMOTE].max_htlc_value_in_flight_msat
)
return max_inflight - current_htlc_sum
def can_pay(self, amount_msat: int, *, check_frozen=False) -> bool:
"""Returns whether we can add an HTLC of given value."""

19
tests/test_lnchannel.py
View File

@@ -738,24 +738,31 @@ class TestAvailableToSpend(ElectrumTestCase):
local_max_inflight=1000000000,
remote_max_inflight=2000000000)
# alice can send 20 but bob can only receive 10, because of stricter receiving rules
self.assertEqual(2000000000, alice_channel.available_to_spend(LOCAL))
self.assertEqual(1000000000, bob_channel.available_to_spend(REMOTE))
# bob can send 10, alice can receive 10
self.assertEqual(1000000000, bob_channel.available_to_spend(LOCAL))
self.assertEqual(1000000000, alice_channel.available_to_spend(REMOTE))
paymentPreimage1 = b"\x01" * 32
htlc = UpdateAddHtlc(
payment_hash=bitcoin.sha256(paymentPreimage1),
amount_msat=1500000000,
amount_msat=1000000000,
cltv_abs=5,
timestamp=0,
)
# put 15mBTC inflight a->b
# put 10mBTC inflight a->b
alice_idx1 = alice_channel.add_htlc(htlc).htlc_id
bob_idx1 = bob_channel.receive_htlc(htlc).htlc_id
force_state_transition(alice_channel, bob_channel)
self.assertEqual(500000000, alice_channel.available_to_spend(LOCAL))
self.assertEqual(1000000000, alice_channel.available_to_spend(LOCAL))
self.assertEqual(0, bob_channel.available_to_spend(REMOTE))
self.assertEqual(1000000000, bob_channel.available_to_spend(LOCAL))
self.assertEqual(1000000000, alice_channel.available_to_spend(REMOTE))
paymentPreimage2 = b"\x02" * 32
htlc2 = UpdateAddHtlc(
@@ -764,7 +771,6 @@ class TestAvailableToSpend(ElectrumTestCase):
cltv_abs=5,
timestamp=0,
)
# try to add another 15mBTC HTLC while 15mBTC already inflight
with self.assertRaises(lnutil.PaymentFailure):
alice_idx2 = alice_channel.add_htlc(htlc2).htlc_id
@@ -775,7 +781,10 @@ class TestAvailableToSpend(ElectrumTestCase):
force_state_transition(alice_channel, bob_channel)
self.assertEqual(2000000000, alice_channel.available_to_spend(LOCAL))
self.assertEqual(1000000000, alice_channel.available_to_spend(REMOTE))
self.assertEqual(1000000000, bob_channel.available_to_spend(LOCAL))
self.assertEqual(1000000000, alice_channel.available_to_spend(REMOTE))
class TestAvailableToSpendAnchors(TestAvailableToSpend):