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Merge pull request #9837 from spesmilo/htlc_slots_left

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pass number of htlc_slots_left to suggest_splits
This commit is contained in:
ThomasV
2025-05-20 12:55:45 +02:00
committed by GitHub
parent 4e64a880fc e433b8d5bf
commit d1917b2951
4 changed files with 66 additions and 34 deletions
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27
electrum/lnchannel.py
View File

@@ -1113,7 +1113,7 @@ class Channel(AbstractChannel):
if amount_msat < chan_config.htlc_minimum_msat:
raise PaymentFailure(f'HTLC value too small: {amount_msat} msat')
if self.too_many_htlcs(htlc_proposer):
if self.htlc_slots_left(htlc_proposer) == 0:
raise PaymentFailure('Too many HTLCs already in channel')
if amount_msat > self.remaining_max_inflight(htlc_receiver):
@@ -1126,7 +1126,7 @@ class Channel(AbstractChannel):
if max_can_send_msat < amount_msat:
raise PaymentFailure(f'Not enough balance. can send: {max_can_send_msat}, tried: {amount_msat}')
def too_many_htlcs(self, htlc_proposer: HTLCOwner) -> bool:
def htlc_slots_left(self, htlc_proposer: HTLCOwner) -> int:
# check "max_accepted_htlcs"
htlc_receiver = htlc_proposer.inverted()
ctn = self.get_next_ctn(htlc_receiver)
@@ -1134,17 +1134,16 @@ class Channel(AbstractChannel):
# If proposer is LOCAL we apply stricter checks as that is behaviour we can control.
# This should lead to fewer disagreements (i.e. channels failing).
strict = (htlc_proposer == LOCAL)
# this is the loose check BOLT-02 specifies:
if len(self.hm.htlcs_by_direction(htlc_receiver, direction=RECEIVED, ctn=ctn)) + 1 > chan_config.max_accepted_htlcs:
return True
# however, c-lightning is a lot stricter, so extra checks:
# https://github.com/ElementsProject/lightning/blob/4dcd4ca1556b13b6964a10040ba1d5ef82de4788/channeld/full_channel.c#L581
if strict:
max_concurrent_htlcs = min(self.config[htlc_proposer].max_accepted_htlcs,
self.config[htlc_receiver].max_accepted_htlcs)
if len(self.hm.htlcs(htlc_receiver, ctn=ctn)) + 1 > max_concurrent_htlcs:
return True
return False
if not strict:
# this is the loose check BOLT-02 specifies:
return chan_config.max_accepted_htlcs - len(self.hm.htlcs_by_direction(htlc_receiver, direction=RECEIVED, ctn=ctn))
else:
# however, c-lightning is a lot stricter, so extra checks:
# https://github.com/ElementsProject/lightning/blob/4dcd4ca1556b13b6964a10040ba1d5ef82de4788/channeld/full_channel.c#L581
max_concurrent_htlcs = min(
self.config[htlc_proposer].max_accepted_htlcs,
self.config[htlc_receiver].max_accepted_htlcs)
return max_concurrent_htlcs - len(self.hm.htlcs(htlc_receiver, ctn=ctn))
def remaining_max_inflight(self, htlc_receiver: HTLCOwner) -> int:
# check "max_htlc_value_in_flight_msat"
@@ -1579,7 +1578,7 @@ class Channel(AbstractChannel):
)
max_send_msat = min(max_send_msat, self.remaining_max_inflight(receiver))
if self.too_many_htlcs(sender):
if self.htlc_slots_left(sender) == 0:
max_send_msat = 0
max_send_msat = max(max_send_msat, 0)

2
electrum/lnworker.py
View File

@@ -1926,7 +1926,7 @@ class LNWallet(LNWorker):
receiver_pubkey: bytes,
) -> List['SplitConfigRating']:
channels_with_funds = {
(chan.channel_id, chan.node_id): int(chan.available_to_spend(HTLCOwner.LOCAL))
(chan.channel_id, chan.node_id): ( int(chan.available_to_spend(HTLCOwner.LOCAL)), chan.htlc_slots_left(HTLCOwner.LOCAL))
for chan in my_active_channels
}
# if we have a direct channel it's preferrable to send a single part directly through this

30
electrum/mpp_split.py
View File

@@ -15,7 +15,7 @@ MAX_PARTS = 5 # maximum number of parts for splitting
# maps a channel (channel_id, node_id) to the funds it has available
ChannelsFundsInfo = Dict[Tuple[bytes, bytes], int]
ChannelsFundsInfo = Dict[Tuple[bytes, bytes], Tuple[int, int]]
class SplitConfig(dict, Dict[Tuple[bytes, bytes], List[int]]):
@@ -105,7 +105,7 @@ def rate_config(
total_amount = config.total_config_amount()
for channel, amounts in config.items():
funds = channels_with_funds[channel]
funds, slots = channels_with_funds[channel]
if amounts:
for amount in amounts:
rating += amount * amount / (total_amount * total_amount) # penalty to favor equal distribution of amounts
@@ -116,7 +116,8 @@ def rate_config(
def suggest_splits(
amount_msat: int, channels_with_funds: ChannelsFundsInfo,
amount_msat: int,
channels_with_funds: ChannelsFundsInfo,
exclude_single_part_payments=False,
exclude_multinode_payments=False,
exclude_single_channel_splits=False
@@ -132,32 +133,37 @@ def suggest_splits(
"""
configs = []
channels_order = list(channels_with_funds.keys())
channel_keys = list(channels_with_funds.keys())
# generate multiple configurations to get more configurations (there is randomness in this loop)
for _ in range(CANDIDATES_PER_LEVEL):
# we want to have configurations with no splitting to many splittings
for target_parts in range(1, MAX_PARTS):
config = SplitConfig()
# randomly split amount into target_parts chunks
split_amounts = split_amount_normal(amount_msat, target_parts)
# randomly distribute amounts over channels
for amount in split_amounts:
random.shuffle(channels_order)
random.shuffle(channel_keys)
# we check each channel and try to put the funds inside, break if we succeed
for c in channels_order:
for c in channel_keys:
if c not in config:
config[c] = []
if sum(config[c]) + amount <= channels_with_funds[c]:
channel_funds, channel_slots = channels_with_funds[c]
if sum(config[c]) + amount <= channel_funds and len(config[c]) < channel_slots:
config[c].append(amount)
break
# if we don't succeed to put the amount anywhere,
# we try to fill up channels and put the rest somewhere else
else:
distribute_amount = amount
for c in channels_order:
funds_left = channels_with_funds[c] - sum(config[c])
for c in channel_keys:
channel_funds, channel_slots = channels_with_funds[c]
slots_left = channel_slots - len(config[c])
if slots_left == 0:
# no slot left in that channel
continue
funds_left = channel_funds - sum(config[c])
# it would be good to not fill the full channel if possible
add_amount = min(funds_left, distribute_amount)
config[c].append(add_amount)
@@ -165,7 +171,7 @@ def suggest_splits(
if distribute_amount == 0:
break
if config.total_config_amount() != amount_msat:
raise NoPathFound('Cannot distribute payment over channels.')
continue
if target_parts > 1 and config.is_any_amount_smaller_than_min_part_size():
if target_parts == 2:
# if there are already too small parts at the first split excluding single
@@ -175,6 +181,8 @@ def suggest_splits(
continue
assert config.total_config_amount() == amount_msat
configs.append(config)
if not configs:
raise NoPathFound('Cannot distribute payment over channels.')
configs = remove_duplicates(configs)

41
tests/test_mpp_split.py
View File

@@ -15,10 +15,10 @@ class TestMppSplit(ElectrumTestCase):
random.seed(0)
# key tuple denotes (channel_id, node_id)
self.channels_with_funds = {
(b"0", b"0"): 1_000_000_000,
(b"1", b"1"): 500_000_000,
(b"2", b"0"): 302_000_000,
(b"3", b"2"): 101_000_000,
(b"0", b"0"): (1_000_000_000, 3),
(b"1", b"1"): (500_000_000, 2),
(b"2", b"0"): (302_000_000, 2),
(b"3", b"2"): (101_000_000, 1),
}
def tearDown(self):
@@ -51,7 +51,7 @@ class TestMppSplit(ElectrumTestCase):
with self.subTest(msg="do a payment with the maximal amount spendable over all channels"):
splits = mpp_split.suggest_splits(
sum(self.channels_with_funds.values()), self.channels_with_funds, exclude_single_part_payments=True)
sum([x[0] for x in self.channels_with_funds.values()]), self.channels_with_funds, exclude_single_part_payments=True)
self.assertEqual({
(b"0", b"0"): [1_000_000_000],
(b"1", b"1"): [500_000_000],
@@ -68,6 +68,25 @@ class TestMppSplit(ElectrumTestCase):
# a splitting of the parts into two
self.assertEqual(2, splits[4].config.number_parts())
with self.subTest(msg="no htlc slots available"):
channels = self.channels_with_funds.copy()
# set all available slots to 0
for chan, (amount, _slots) in channels.items():
channels[chan] = (amount, 0)
with self.assertRaises(NoPathFound):
mpp_split.suggest_splits(20_000_000, channels, exclude_single_part_payments=False)
with self.subTest(msg="only one channel can add htlcs"):
channels = self.channels_with_funds.copy()
# set all available slots to 0 except for the first channel
for chan, (amount, _slots) in channels.items():
if chan != (b"0", b"0"):
channels[chan] = (amount, 0)
splits = mpp_split.suggest_splits(1_000_000_000, channels, exclude_single_part_payments=True)
for split in splits:
# check that the whole amount has been split on this channel
self.assertEqual(sum(split.config[(b"0", b"0")]), 1_000_000_000)
def test_send_to_single_node(self):
splits = mpp_split.suggest_splits(1_000_000_000, self.channels_with_funds, exclude_single_part_payments=False, exclude_multinode_payments=True)
for split in splits:
@@ -75,7 +94,10 @@ class TestMppSplit(ElectrumTestCase):
def test_saturation(self):
"""Split configurations which spend the full amount in a channel should be avoided."""
channels_with_funds = {(b"0", b"0"): 159_799_733_076, (b"1", b"1"): 499_986_152_000}
channels_with_funds = {
(b"0", b"0"): (159_799_733_076, 1),
(b"1", b"1"): (499_986_152_000, 1)
}
splits = mpp_split.suggest_splits(600_000_000_000, channels_with_funds, exclude_single_part_payments=True)
uses_full_amount = False
@@ -114,18 +136,21 @@ class TestMppSplit(ElectrumTestCase):
def test_suggest_splits_single_channel(self):
channels_with_funds = {
(b"0", b"0"): 1_000_000_000,
(b"0", b"0"): (1_000_000_000, 3),
}
with self.subTest(msg="do a payment with the maximal amount spendable on a single channel"):
splits = mpp_split.suggest_splits(1_000_000_000, channels_with_funds, exclude_single_part_payments=False)
self.assertEqual(1, len(splits[0].config[(b"0", b"0")]))
self.assertEqual({(b"0", b"0"): [1_000_000_000]}, splits[0].config)
with self.subTest(msg="test sending an amount greater than what we have available"):
self.assertRaises(NoPathFound, mpp_split.suggest_splits, *(1_100_000_000, channels_with_funds))
with self.subTest(msg="test sending a large amount over a single channel in chunks"):
mpp_split.PART_PENALTY = 0.5
splits = mpp_split.suggest_splits(1_000_000_000, channels_with_funds, exclude_single_part_payments=False)
self.assertEqual(2, len(splits[0].config[(b"0", b"0")]))
with self.subTest(msg="test sending a large amount over a single channel in chunks"):
mpp_split.PART_PENALTY = 0.3
splits = mpp_split.suggest_splits(1_000_000_000, channels_with_funds, exclude_single_part_payments=False)