/// A wrapper around the various hop representations.
///
/// Used to construct a [`PathBuildingHop`] and to estimate [`EffectiveCapacity`].
+#[derive(Clone, Debug)]
enum CandidateRouteHop<'a> {
/// A hop from the payer to the next hop to the payee, where the outbound liquidity is known.
FirstHop {
/// Fee values should be updated only in the context of the whole path, see update_value_and_recompute_fees.
/// These fee values are useful to choose hops as we traverse the graph "payee-to-payer".
#[derive(Clone, Debug)]
-struct PathBuildingHop {
- // The RouteHintHop fields which will eventually be used if this hop is used in a final Route.
- // Note that node_features is calculated separately after our initial graph walk.
+struct PathBuildingHop<'a> {
+ // Note that this should be dropped in favor of loading it from CandidateRouteHop, but doing so
+ // is a larger refactor and will require careful performance analysis.
node_id: NodeId,
- short_channel_id: u64,
- channel_features: ChannelFeatures,
+ candidate: CandidateRouteHop<'a>,
fee_msat: u64,
- cltv_expiry_delta: u32,
/// Minimal fees required to route to the source node of the current hop via any of its inbound channels.
src_lowest_inbound_fees: RoutingFees,
- /// Fees of the channel used in this hop.
- channel_fees: RoutingFees,
/// All the fees paid *after* this channel on the way to the destination
next_hops_fee_msat: u64,
- /// Fee paid for the use of the current channel (see channel_fees).
+ /// Fee paid for the use of the current channel (see candidate.fees()).
/// The value will be actually deducted from the counterparty balance on the previous link.
hop_use_fee_msat: u64,
/// Used to compare channels when choosing the for routing.
/// an estimated cost of reaching this hop.
/// Might get stale when fees are recomputed. Primarily for internal use.
total_fee_msat: u64,
- /// This is useful for update_value_and_recompute_fees to make sure
- /// we don't fall below the minimum. Should not be updated manually and
- /// generally should not be accessed.
- htlc_minimum_msat: u64,
/// A mirror of the same field in RouteGraphNode. Note that this is only used during the graph
/// walk and may be invalid thereafter.
path_htlc_minimum_msat: u64,
// Instantiated with a list of hops with correct data in them collected during path finding,
// an instance of this struct should be further modified only via given methods.
#[derive(Clone)]
-struct PaymentPath {
- hops: Vec<(PathBuildingHop, NodeFeatures)>,
+struct PaymentPath<'a> {
+ hops: Vec<(PathBuildingHop<'a>, NodeFeatures)>,
}
-impl PaymentPath {
+impl<'a> PaymentPath<'a> {
// TODO: Add a value_msat field to PaymentPath and use it instead of this function.
fn get_value_msat(&self) -> u64 {
self.hops.last().unwrap().0.fee_msat
// set it too high just to maliciously take more fees by exploiting this
// match htlc_minimum_msat logic.
let mut cur_hop_transferred_amount_msat = total_fee_paid_msat + value_msat;
- if let Some(extra_fees_msat) = cur_hop.htlc_minimum_msat.checked_sub(cur_hop_transferred_amount_msat) {
+ if let Some(extra_fees_msat) = cur_hop.candidate.htlc_minimum_msat().checked_sub(cur_hop_transferred_amount_msat) {
// Note that there is a risk that *previous hops* (those closer to us, as we go
// payee->our_node here) would exceed their htlc_maximum_msat or available balance.
//
// Irrelevant for the first hop, as it doesn't have the previous hop, and the use of
// this channel is free for us.
if i != 0 {
- if let Some(new_fee) = compute_fees(cur_hop_transferred_amount_msat, cur_hop.channel_fees) {
+ if let Some(new_fee) = compute_fees(cur_hop_transferred_amount_msat, cur_hop.candidate.fees()) {
cur_hop.hop_use_fee_msat = new_fee;
total_fee_paid_msat += new_fee;
} else {
}
PathBuildingHop {
node_id: $dest_node_id.clone(),
- short_channel_id: 0,
- channel_features: $candidate.features(),
+ candidate: $candidate.clone(),
fee_msat: 0,
- cltv_expiry_delta: 0,
src_lowest_inbound_fees: RoutingFees {
base_msat: fee_base_msat,
proportional_millionths: fee_proportional_millionths,
},
- channel_fees: $candidate.fees(),
next_hops_fee_msat: u64::max_value(),
hop_use_fee_msat: u64::max_value(),
total_fee_msat: u64::max_value(),
- htlc_minimum_msat: $candidate.htlc_minimum_msat(),
path_htlc_minimum_msat,
path_penalty_msat: u64::max_value(),
was_processed: false,
old_entry.hop_use_fee_msat = hop_use_fee_msat;
old_entry.total_fee_msat = total_fee_msat;
old_entry.node_id = $dest_node_id.clone();
- old_entry.short_channel_id = short_channel_id;
- old_entry.channel_features = $candidate.features();
+ old_entry.candidate = $candidate.clone();
old_entry.fee_msat = 0; // This value will be later filled with hop_use_fee_msat of the following channel
- old_entry.cltv_expiry_delta = $candidate.cltv_expiry_delta();
- old_entry.channel_fees = $candidate.fees();
- old_entry.htlc_minimum_msat = $candidate.htlc_minimum_msat();
old_entry.path_htlc_minimum_msat = path_htlc_minimum_msat;
old_entry.path_penalty_msat = path_penalty_msat;
#[cfg(any(test, feature = "fuzztarget"))]
let mut features_set = false;
if let Some(first_channels) = first_hop_targets.get(&ordered_hops.last().unwrap().0.node_id) {
for details in first_channels {
- if details.short_channel_id.unwrap() == ordered_hops.last().unwrap().0.short_channel_id {
+ if details.short_channel_id.unwrap() == ordered_hops.last().unwrap().0.candidate.short_channel_id() {
ordered_hops.last_mut().unwrap().1 = details.counterparty.features.to_context();
features_set = true;
break;
// so that fees paid for a HTLC forwarding on the current channel are
// associated with the previous channel (where they will be subtracted).
ordered_hops.last_mut().unwrap().0.fee_msat = new_entry.hop_use_fee_msat;
- ordered_hops.last_mut().unwrap().0.cltv_expiry_delta = new_entry.cltv_expiry_delta;
ordered_hops.push((new_entry.clone(), NodeFeatures::empty()));
}
ordered_hops.last_mut().unwrap().0.fee_msat = value_contribution_msat;
ordered_hops.last_mut().unwrap().0.hop_use_fee_msat = 0;
- ordered_hops.last_mut().unwrap().0.cltv_expiry_delta = final_cltv_expiry_delta;
log_trace!(logger, "Found a path back to us from the target with {} hops contributing up to {} msat: {:?}",
ordered_hops.len(), value_contribution_msat, ordered_hops);
// on the same liquidity in future paths.
let mut prevented_redundant_path_selection = false;
for (payment_hop, _) in payment_path.hops.iter() {
- let channel_liquidity_available_msat = bookkeeped_channels_liquidity_available_msat.get_mut(&payment_hop.short_channel_id).unwrap();
+ let channel_liquidity_available_msat = bookkeeped_channels_liquidity_available_msat.get_mut(&payment_hop.candidate.short_channel_id()).unwrap();
let mut spent_on_hop_msat = value_contribution_msat;
let next_hops_fee_msat = payment_hop.next_hops_fee_msat;
spent_on_hop_msat += next_hops_fee_msat;
// If we weren't capped by hitting a liquidity limit on a channel in the path,
// we'll probably end up picking the same path again on the next iteration.
// Decrease the available liquidity of a hop in the middle of the path.
- let victim_scid = payment_path.hops[(payment_path.hops.len() - 1) / 2].0.short_channel_id;
+ let victim_scid = payment_path.hops[(payment_path.hops.len() - 1) / 2].0.candidate.short_channel_id();
log_trace!(logger, "Disabling channel {} for future path building iterations to avoid duplicates.", victim_scid);
let victim_liquidity = bookkeeped_channels_liquidity_available_msat.get_mut(&victim_scid).unwrap();
*victim_liquidity = 0;
// Now, substract the overpaid value from the most-expensive path.
// TODO: this could also be optimized by also sorting by feerate_per_sat_routed,
// so that the sender pays less fees overall. And also htlc_minimum_msat.
- cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.0.channel_fees.proportional_millionths as u64).sum::<u64>() });
+ cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.0.candidate.fees().proportional_millionths as u64).sum::<u64>() });
let expensive_payment_path = cur_route.first_mut().unwrap();
// We already dropped all the small channels above, meaning all the
// remaining channels are larger than remaining overpaid_value_msat.
drawn_routes.sort_by_key(|paths| paths.iter().map(|path| path.get_total_fee_paid_msat()).sum::<u64>());
let mut selected_paths = Vec::<Vec<Result<RouteHop, LightningError>>>::new();
for payment_path in drawn_routes.first().unwrap() {
- selected_paths.push(payment_path.hops.iter().map(|(payment_hop, node_features)| {
+ let mut path = payment_path.hops.iter().map(|(payment_hop, node_features)| {
Ok(RouteHop {
pubkey: PublicKey::from_slice(payment_hop.node_id.as_slice()).map_err(|_| LightningError{err: format!("Public key {:?} is invalid", &payment_hop.node_id), action: ErrorAction::IgnoreAndLog(Level::Trace)})?,
node_features: node_features.clone(),
- short_channel_id: payment_hop.short_channel_id,
- channel_features: payment_hop.channel_features.clone(),
+ short_channel_id: payment_hop.candidate.short_channel_id(),
+ channel_features: payment_hop.candidate.features(),
fee_msat: payment_hop.fee_msat,
- cltv_expiry_delta: payment_hop.cltv_expiry_delta,
+ cltv_expiry_delta: payment_hop.candidate.cltv_expiry_delta(),
})
- }).collect());
+ }).collect::<Vec<_>>();
+ let mut prev_cltv_expiry_delta = final_cltv_expiry_delta;
+ for hop in path.iter_mut().rev() {
+ core::mem::swap(&mut prev_cltv_expiry_delta, &mut hop.as_mut().unwrap().cltv_expiry_delta);
+ }
+ selected_paths.push(path);
}
if let Some(features) = &payee.features {
projects / rust-lightning / commitdiff