Trampoline forwarding #3976
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Trampoline forwarding #3976
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👋 Hi! This PR is now in draft status. |
a-mpch
commented
Jul 30, 2025
lightning/src/ln/channelmanager.rs
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| #[cfg(not(any(test, feature = "_test_utils")))] | ||
| let retry_strategy = Retry::Attempts(3); | ||
| #[cfg(any(test, feature = "_test_utils"))] |
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Not really a fan on this one, I'd accept any idea
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drafting while rebasing again and fixing minor issues of CI |
Ensure that the Trampolin onion's amount and CLTV values does not exceed the limitations imposed by the outer onion. Co-authored-by: Arik Sosman <[email protected]>
To process errors returned from downstream nodes when forwarding between Trampoline nodes, we need to store information beyond what's available in `HTLCPreviousHopData`, suc as the used hops as the newly generated outer onion's session_priv. To that end, we add a new variant to `HTLCSource` in this commit, which futre-proofs mapping an outbound forward to an incoming MPP. Co-authored-by: Arik Sosman <[email protected]>
The previously existing `HTLCDestination` do not map nicely to the failure vent of a Trampoline forward, so we introduce a new variant to fill the gap. Co-authored-by: Arik Sosman <[email protected]>
a-mpch
commented
Jul 31, 2025
| { | ||
| // We use Unkonwn Failure code instead of TemporaryTrampolineFailure because errors uses u16 bolt04 codes. | ||
| let payment_failed_conditions = PaymentFailedConditions::new() | ||
| .expected_htlc_error_data(LocalHTLCFailureReason::UnknownFailureCode { code: 16409 }, &[0; 0]); |
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Not really sure on testing like this or just add the TemporaryTrampolineFailure
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Codecov Report❌ Patch coverage is Additional details and impacted files@@ Coverage Diff @@
## main #3976 +/- ##
=========================================
Coverage 88.91% 88.91%
=========================================
Files 174 174
Lines 124232 125526 +1294
Branches 124232 125526 +1294
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+ Hits 110455 111610 +1155
- Misses 11301 11419 +118
- Partials 2476 2497 +21
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In this commit, we expand our forwarding logic to do ad-hoc pathfinding to subsequent Trampoline nodes, covering both blinded and unblinded scenarios. We set a constant for retrying payments in Trampoline nodes up to 3 failures. We further modify our error propagation logic to handle Trampoline forward HTLC failures. Co-authored-by: Arik Sosman <[email protected]>
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Supersedes #3711
Rebase and fixes to a sooner
mainbranch.Some changes from the previous branch:
What's missing: