Trampoline

[valentinewallace]

• Serialization
  • [AP] Outbound
    • Support sending an HTLC with a trampoline onion packet (Serialize Trampoline payloads in outbound onions. #2756)
    • Support constructing a nested trampoline onion packet (Trampoline onion construction vectors #2906)
    • Support serializing blinded path hops (Serialize blinded Trampoline hops #3007)
    • Allow variable length nested onions? (Consensus with @t-bast is probably not in the immediate future, due to privacy concerns)
      • Variable-length onion packet (Serialize Trampoline payloads in outbound onions. #2756)
  • [AP] Inbound
    • Support deserializing Trampoline packets (Trampoline Onion Deserialization #3006)
    • Support receiving a payment containing a trampoline onion packet
    • Support encoding+parsing trampoline onion errors
• Wire Communication
  • Feature flag (Serialize Trampoline payloads in outbound onions. #2756)
• Routing
  • Support pathfinding for a trampoline payment
    • [AP] Trampoline packet assembly from Path (Trampoline Payload Construction Method #3386)
    • Flag-aware hop selection for packet construction (WIP: https://github.com/arik-so/rust-lightning/tree/arik/trampoline/pathfinding)
    • Calculate onion length dynamically (Calculate Trampoline onion packet sizes dynamically. #3333)
    • Router for LSP clients to return a single-hop route using Trampoline
  • Forwarding payments as Trampoline node
    • [AP] Support forwarding a trampoline payment to the next trampoline hop
      • Shorten CLTV (ensure it's relative)
      • Support retrying a trampoline payment as an intermediate trampoline node
    • Support aggregating MPP payments at intermediate trampoline hops
  • Advertise Trampoline support
• Interaction
  • [AP] Expose method for sending to Trampoline node (covered implicitly by Trampoline Payload Construction Method #3386, which modifies the call stack originating from send_payment_for_verified_bolt12_invoice)
  • Support reading and creating invoices with trampoline route hints, in BOLT11 + BOLT12 (Support Trampoline flag in BOLT12 invoices #3446)
  • Interaction with blinded paths: resolved to be mandatory.
• Bindings Support

AP: Prerequisite for async payments MVP.