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lnchannel: create helper functions too_many_htlcs and remaining_max_inflight

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ThomasV
2025-05-14 09:59:33 +02:00
parent c3f0993e53
commit fed526bbdf
1 changed files with 19 additions and 10 deletions
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29
electrum/lnchannel.py
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@@ -1099,29 +1099,41 @@ 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, strict):
raise PaymentFailure('Too many HTLCs already in channel')
if amount_msat > self.remaining_max_inflight(htlc_receiver):
raise PaymentFailure(
f'HTLC value sum (sum of pending htlcs plus new htlc) '
f'would exceed max allowed: {chan_config.max_htlc_value_in_flight_msat/1000} sat')
# check proposer can afford htlc
max_can_send_msat = self.available_to_spend(htlc_proposer, strict=strict)
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, strict:bool) -> bool:
# check "max_accepted_htlcs"
htlc_receiver = htlc_proposer.inverted()
ctn = self.get_next_ctn(htlc_receiver)
chan_config = self.config[htlc_receiver]
# 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:
raise PaymentFailure('Too many HTLCs already in channel')
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:
raise PaymentFailure('Too many HTLCs already in channel')
return True
return False
def remaining_max_inflight(self, htlc_receiver: HTLCOwner) -> int:
# 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())
if current_htlc_sum + amount_msat > chan_config.max_htlc_value_in_flight_msat:
raise PaymentFailure(f'HTLC value sum (sum of pending htlcs: {current_htlc_sum/1000} sat '
f'plus new htlc: {amount_msat/1000} sat) '
f'would exceed max allowed: {chan_config.max_htlc_value_in_flight_msat/1000} sat')
return self.config[htlc_receiver].max_htlc_value_in_flight_msat - current_htlc_sum
def can_pay(self, amount_msat: int, *, check_frozen=False) -> bool:
"""Returns whether we can add an HTLC of given value."""
@@ -1541,10 +1553,7 @@ class Channel(AbstractChannel):
),
)
ctn = self.get_next_ctn(receiver)
current_htlc_sum = htlcsum(self.hm.htlcs_by_direction(receiver, direction=RECEIVED, ctn=ctn).values())
remaining_max_inflight = self.config[receiver].max_htlc_value_in_flight_msat - current_htlc_sum
max_send_msat = min(max_send_msat, remaining_max_inflight)
max_send_msat = min(max_send_msat, self.remaining_max_inflight(receiver))
max_send_msat = max(max_send_msat, 0)
return max_send_msat