From: Valentine Wallace Date: Fri, 10 May 2024 21:31:51 +0000 (-0400) Subject: Extract onion_utils::build_onion_payloads_callback helper. X-Git-Tag: v0.0.124-beta~116^2~6 X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;ds=sidebyside;h=bcdb67e5602c3c0d6a94893ea1681456061f4474;p=rust-lightning Extract onion_utils::build_onion_payloads_callback helper. Will be useful when we want to calculate the total size of the payloads without actually allocating for them. --- diff --git a/lightning/src/ln/onion_utils.rs b/lightning/src/ln/onion_utils.rs index a90dd837e..2aba2c757 100644 --- a/lightning/src/ln/onion_utils.rs +++ b/lightning/src/ln/onion_utils.rs @@ -7,6 +7,7 @@ // You may not use this file except in accordance with one or both of these // licenses. +use crate::blinded_path::BlindedHop; use crate::crypto::chacha20::ChaCha20; use crate::crypto::streams::ChaChaReader; use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields}; @@ -14,7 +15,7 @@ use crate::ln::msgs; use crate::ln::types::{PaymentHash, PaymentPreimage}; use crate::ln::wire::Encode; use crate::routing::gossip::NetworkUpdate; -use crate::routing::router::{BlindedTail, Path, RouteHop}; +use crate::routing::router::{Path, RouteHop}; use crate::sign::NodeSigner; use crate::util::errors::{self, APIError}; use crate::util::logger::Logger; @@ -178,14 +179,56 @@ pub(super) fn build_onion_payloads<'a>( path: &'a Path, total_msat: u64, recipient_onion: &'a RecipientOnionFields, starting_htlc_offset: u32, keysend_preimage: &Option, ) -> Result<(Vec>, u64, u32), APIError> { - let mut cur_value_msat = 0u64; - let mut cur_cltv = starting_htlc_offset; - let mut last_short_channel_id = 0; let mut res: Vec = Vec::with_capacity( path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len()), ); + let blinded_tail_with_hop_iter = path.blinded_tail.as_ref().map(|bt| BlindedTailHopIter { + hops: bt.hops.iter(), + blinding_point: bt.blinding_point, + final_value_msat: bt.final_value_msat, + excess_final_cltv_expiry_delta: bt.excess_final_cltv_expiry_delta, + }); + + let (value_msat, cltv) = build_onion_payloads_callback( + path.hops.iter(), + blinded_tail_with_hop_iter, + total_msat, + recipient_onion, + starting_htlc_offset, + keysend_preimage, + |action, payload| match action { + PayloadCallbackAction::PushBack => res.push(payload), + PayloadCallbackAction::PushFront => res.insert(0, payload), + }, + )?; + Ok((res, value_msat, cltv)) +} - for (idx, hop) in path.hops.iter().rev().enumerate() { +struct BlindedTailHopIter<'a, I: Iterator> { + hops: I, + blinding_point: PublicKey, + final_value_msat: u64, + excess_final_cltv_expiry_delta: u32, +} +enum PayloadCallbackAction { + PushBack, + PushFront, +} +fn build_onion_payloads_callback<'a, H, B, F>( + hops: H, mut blinded_tail: Option>, total_msat: u64, + recipient_onion: &'a RecipientOnionFields, starting_htlc_offset: u32, + keysend_preimage: &Option, mut callback: F, +) -> Result<(u64, u32), APIError> +where + H: DoubleEndedIterator, + B: ExactSizeIterator, + F: FnMut(PayloadCallbackAction, msgs::OutboundOnionPayload<'a>), +{ + let mut cur_value_msat = 0u64; + let mut cur_cltv = starting_htlc_offset; + let mut last_short_channel_id = 0; + + for (idx, hop) in hops.rev().enumerate() { // First hop gets special values so that it can check, on receipt, that everything is // exactly as it should be (and the next hop isn't trying to probe to find out if we're // the intended recipient). @@ -196,45 +239,55 @@ pub(super) fn build_onion_payloads<'a>( cur_cltv }; if idx == 0 { - if let Some(BlindedTail { + if let Some(BlindedTailHopIter { blinding_point, hops, final_value_msat, excess_final_cltv_expiry_delta, .. - }) = &path.blinded_tail + }) = blinded_tail.take() { - let mut blinding_point = Some(*blinding_point); - for (i, blinded_hop) in hops.iter().enumerate() { - if i == hops.len() - 1 { + let mut blinding_point = Some(blinding_point); + let hops_len = hops.len(); + for (i, blinded_hop) in hops.enumerate() { + if i == hops_len - 1 { cur_value_msat += final_value_msat; - res.push(msgs::OutboundOnionPayload::BlindedReceive { - sender_intended_htlc_amt_msat: *final_value_msat, - total_msat, - cltv_expiry_height: cur_cltv + excess_final_cltv_expiry_delta, - encrypted_tlvs: &blinded_hop.encrypted_payload, - intro_node_blinding_point: blinding_point.take(), - keysend_preimage: *keysend_preimage, - custom_tlvs: &recipient_onion.custom_tlvs, - }); + callback( + PayloadCallbackAction::PushBack, + msgs::OutboundOnionPayload::BlindedReceive { + sender_intended_htlc_amt_msat: final_value_msat, + total_msat, + cltv_expiry_height: cur_cltv + excess_final_cltv_expiry_delta, + encrypted_tlvs: &blinded_hop.encrypted_payload, + intro_node_blinding_point: blinding_point.take(), + keysend_preimage: *keysend_preimage, + custom_tlvs: &recipient_onion.custom_tlvs, + }, + ); } else { - res.push(msgs::OutboundOnionPayload::BlindedForward { - encrypted_tlvs: &blinded_hop.encrypted_payload, - intro_node_blinding_point: blinding_point.take(), - }); + callback( + PayloadCallbackAction::PushBack, + msgs::OutboundOnionPayload::BlindedForward { + encrypted_tlvs: &blinded_hop.encrypted_payload, + intro_node_blinding_point: blinding_point.take(), + }, + ); } } } else { - res.push(msgs::OutboundOnionPayload::Receive { - payment_data: recipient_onion.payment_secret.map(|payment_secret| { - msgs::FinalOnionHopData { payment_secret, total_msat } - }), - payment_metadata: recipient_onion.payment_metadata.as_ref(), - keysend_preimage: *keysend_preimage, - custom_tlvs: &recipient_onion.custom_tlvs, - sender_intended_htlc_amt_msat: value_msat, - cltv_expiry_height: cltv, - }); + callback( + PayloadCallbackAction::PushBack, + msgs::OutboundOnionPayload::Receive { + payment_data: recipient_onion.payment_secret.map(|payment_secret| { + msgs::FinalOnionHopData { payment_secret, total_msat } + }), + payment_metadata: recipient_onion.payment_metadata.as_ref(), + keysend_preimage: *keysend_preimage, + custom_tlvs: &recipient_onion.custom_tlvs, + sender_intended_htlc_amt_msat: value_msat, + cltv_expiry_height: cltv, + }, + ); } } else { let payload = msgs::OutboundOnionPayload::Forward { @@ -242,7 +295,7 @@ pub(super) fn build_onion_payloads<'a>( amt_to_forward: value_msat, outgoing_cltv_value: cltv, }; - res.insert(0, payload); + callback(PayloadCallbackAction::PushFront, payload); } cur_value_msat += hop.fee_msat; if cur_value_msat >= 21000000 * 100000000 * 1000 { @@ -254,7 +307,7 @@ pub(super) fn build_onion_payloads<'a>( } last_short_channel_id = hop.short_channel_id; } - Ok((res, cur_value_msat, cur_cltv)) + Ok((cur_value_msat, cur_cltv)) } /// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now