Backport #4682: report sending peer (prev_hop) in OnionMessageIntercepted#3
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saidalaoui-sq merged 3 commits intoJul 1, 2026
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Allow integrations to intercept blinded onion-message hops that identify the next node by short channel id, so LSPS-style protocols can resolve those hops out of band instead of dropping the message. Co-Authored-By: HAL 9000
When the OnionMessenger intercepts an onion message to forward, it now reports which peer sent us the message via a new `prev_hop` field, so handlers can apply source-based policy when deciding whether to forward. `prev_hop` is `None` when the forward is enqueued by a message handler (the BOLT 12 static-invoice-server flow), which isn't given the sending node; otherwise it is the node we received the message from. Co-Authored-By: Claude <noreply@anthropic.com>
The upstream lightningdevkit#4682 commits use impl_ser_tlv_based_enum!, which does not exist on the 0.2.3_fork base. Use the fork's equivalent impl_writeable_tlv_based_enum!, which supports the same tuple-variant syntax and produces a self-consistent Readable/Writeable impl. Amp-Thread-ID: https://ampcode.com/threads/T-019f1bf1-a8e4-745c-8492-3d1c9ff270a0 Co-authored-by: Amp <amp@ampcode.com>
saidalaoui-sq
approved these changes
Jul 1, 2026
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Why
Unblocks BCOIN-7796. To forward BOLT 12 onion messages to offline peers, the routing node (BRN) must filter intercepted messages by sender so it only forwards lit-originated traffic. That source info was added upstream in lightningdevkit/rust-lightning#4682, which is not in any released LDK version (unreleased 0.3-dev). This is the lowest-footprint way to get it onto the
0.2.3_forkbase the routing node pins.What
Cherry-picks the two commits of upstream lightningdevkit#4682 onto
0.2.3_fork, plus one small fork adaptation:2e7cc44c) — introducesNextMessageHopand changesEvent::OnionMessageIntercepted.peer_node_id→next_hop.Event::OnionMessageIntercepted(1a0e5304) — addsprev_hop: Option<PublicKey>(the required change).NextMessageHopserialization to 0.2.3 fork ser macros — upstream usesimpl_ser_tlv_based_enum!, which doesn't exist on this base; swapped to the fork's equivalentimpl_writeable_tlv_based_enum!(same tuple-variant syntax, self-consistent Readable/Writeable).Resulting event shape
Testing
lightning,-background-processor,-net-tokio,-invoice,-liquidity,-rapid-gossip-sync.lightning-testscrate (not consumed by the routing node); resolved by keeping the fork's version, which does not reference the changed event.Follow-up
Once merged, the workspace
[patch.crates-io]pin incequals/lightning-nodebumpsbee3c3cb→ this merge SHA; handler implementation is tracked in BCOIN-7796.