AaronFiore/electrum
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trampoline: fix "pay-to-legacy" workaround when using ACINQ node

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It is the last Trampoline Forwarder that should be checked, not the
first one.

Consider route (of Trampolines only):
Alice-electrum -> T_ACINQ -> T_Hodlister -> Bob-electrum
Even if Bob has a transport open with ACINQ or even if Bob has a channel open with ACINQ,
Alice can safely use end-to-end trampoline for this route: ACINQ will not know who
the recipient is, so they will not try to do pay-to-open (and hold up the payment for minutes...).

related: https://github.com/ACINQ/lightning-kmp/pull/237
This commit is contained in:
SomberNight
2021-07-02 19:42:58 +02:00
parent 3a7f5373ac
commit 04bc7fd28f
1 changed files with 11 additions and 6 deletions
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17
electrum/trampoline.py
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@@ -105,7 +105,7 @@ def create_trampoline_route(
invoice_pubkey:bytes,
invoice_features:int,
my_pubkey: bytes,
trampoline_node_id,
trampoline_node_id: bytes, # the first trampoline in the path; which we are directly connected to
r_tags,
trampoline_fee_level: int,
use_two_trampolines: bool) -> LNPaymentRoute:
@@ -118,6 +118,7 @@ def create_trampoline_route(
or invoice_features.supports(LnFeatures.OPTION_TRAMPOLINE_ROUTING_OPT_ECLAIR)):
if not r_tags: # presumably the recipient has public channels
is_legacy = False
pubkey = trampoline_node_id
else:
# - We choose one routing hint at random, and
# use end-to-end trampoline if that node is a trampoline-forwarder (TF).
@@ -130,16 +131,20 @@ def create_trampoline_route(
r_tag_chosen_for_e2e_trampoline = random.choice(singlehop_r_tags)[0]
pubkey, scid, feebase, feerate, cltv = r_tag_chosen_for_e2e_trampoline
is_legacy = not is_hardcoded_trampoline(pubkey)
# Temporary fix: until ACINQ uses a proper feature bit to detect Phoenix,
# they might try to open channels when payments fail. The ACINQ node does this
# if it is directly connected to the recipient but without enough sending capacity.
# They send a custom "pay-to-open-request", and wait 60+ sec for the recipient to respond.
# Effectively, they hold the HTLC for minutes before failing it.
# see: https://github.com/ACINQ/lightning-kmp/pull/237
if pubkey == TRAMPOLINE_NODES_MAINNET['ACINQ'].pubkey:
is_legacy = True
use_two_trampolines = False
# fee level. the same fee is used for all trampolines
if trampoline_fee_level < len(TRAMPOLINE_FEES):
params = TRAMPOLINE_FEES[trampoline_fee_level]
else:
raise NoPathFound()
# temporary fix: until ACINQ uses a proper feature bit to detect
# Phoenix, they might try to open channels when payments fail
if trampoline_node_id == TRAMPOLINE_NODES_MAINNET['ACINQ'].pubkey:
is_legacy = True
use_two_trampolines = False
# add optional second trampoline
trampoline2 = None
if is_legacy and use_two_trampolines: