Move BOLT11 JIT params to payment metadata#899
Move BOLT11 JIT params to payment metadata#899tnull wants to merge 3 commits intolightningdevkit:mainfrom
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The values describe the `LSPS2` parameters negotiated for JIT-channel receives, not a fee-limit concept owned by the payment store. Rename the public type and internal references while preserving the existing fields, TLV encoding, and `PaymentKind::Bolt11Jit` storage shape for the follow-up refactor. Co-Authored-By: HAL 9000
`LSPS2Parameters` should travel with generated JIT invoices and the returned recipient onion metadata instead of living in a dedicated `PaymentKind::Bolt11Jit` payment-store variant. Store new JIT payments as `PaymentKind::Bolt11`, decode legacy `PaymentKind::Bolt11Jit` records as `PaymentKind::Bolt11`, and reject nonzero `counterparty_skimmed_fee_msat` unless valid BOLT11 `payment_metadata` proves the `LSPS2` fee is allowed. Co-Authored-By: HAL 9000
`PaymentDetails` field 1 only carried `LSPS2Parameters` in an unreleased intermediate layout before JIT data moved into `PaymentKind::Bolt11Jit`. Drop the stale reader path and compatibility fixture while keeping the released legacy `PaymentKind::Bolt11Jit` decoder intact. Co-Authored-By: HAL 9000
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PR looks great. I like the offloading of state to clients. And ofc happy to see usage of lightning/bolts#912 😄
| let payment_hash = invoice.payment_hash(); | ||
| let payment_secret = invoice.payment_secret(); | ||
| let lsp_fee_limits = LSPFeeLimits { | ||
| let lsp_fee_limits = LSPS2Parameters { |
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Not sure if this rename is strictly better. Parameters sounds broader than what it is.
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Yes, that's intentional as we might add more fields in the BOLT12 context that are not 'fee limits'. Sorry, maybe should have given that rationale in the commit description.
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Which parameters are that?
| .payment_metadata( | ||
| Bolt11PaymentMetadata { lsps2_parameters: Some(lsps2_parameters) }.encode(), | ||
| ) | ||
| .require_payment_metadata(); |
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Is it safe to assume that this is universally supported by senders?
| let client_payment = client_node.payment(&client_payment_id).unwrap(); | ||
| match client_payment.kind { | ||
| PaymentKind::Bolt11Jit { counterparty_skimmed_fee_msat, .. } => { | ||
| PaymentKind::Bolt11 { counterparty_skimmed_fee_msat, .. } => { |
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Would it be worth to add some coverage for "skimmed fee with missing/malformed metadata" failing?
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Context
We recently found that for the intended BOLT12-JIT flow we'll have to encode the LSPS2 parameters in the payment metadata (based on lightningdevkit/rust-lightning#4584). As a prefactor to that (and to simplify things for #811, rather than add yet another store type there, just to revert once we get to the BOLT12-JIT changes), we here switch to store the LSPS2 parameters in the BOLT11
payment_metadatarather than persisting them on-disk. To make this safe we'll also need lightningdevkit/rust-lightning#4528, as otherwise the payer could collude with the LSP to rob the payee.Summary
This moves LSPS2/JIT-channel receive parameters out of dedicated payment-store
state and into the BOLT11 invoice
payment_metadata, so the payment store nolonger needs a
PaymentKind::Bolt11Jitvariant for new payments.Changes
LSPFeeLimitstoLSPS2Parameters.Bolt11PaymentMetadatainbolt11.rswith TLV-based encoding.LSPS2Parametersinto BOLT11payment_metadatawhen creating JITinvoices.
PaymentKind::Bolt11.PaymentKind::Bolt11Jitrecords asPaymentKind::Bolt11.payment_metadataprovesthe LSPS2 fee is within the negotiated limit.
PaymentDetailsfield-1 JIT metadata reader, whilekeeping the released legacy
PaymentKind::Bolt11Jitdecoder.prior JIT state is not migrated.