#[derive(Eq, PartialEq)]
struct RouteGraphNode {
node_id: NodeId,
- lowest_fee_to_peer_through_node: u64,
lowest_fee_to_node: u64,
total_cltv_delta: u32,
// The maximum value a yet-to-be-constructed payment path might flow through this node.
impl cmp::Ord for RouteGraphNode {
fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering {
- let other_score = cmp::max(other.lowest_fee_to_peer_through_node, other.path_htlc_minimum_msat)
+ let other_score = cmp::max(other.lowest_fee_to_node, other.path_htlc_minimum_msat)
.saturating_add(other.path_penalty_msat);
- let self_score = cmp::max(self.lowest_fee_to_peer_through_node, self.path_htlc_minimum_msat)
+ let self_score = cmp::max(self.lowest_fee_to_node, self.path_htlc_minimum_msat)
.saturating_add(self.path_penalty_msat);
other_score.cmp(&self_score).then_with(|| other.node_id.cmp(&self.node_id))
}
candidate: CandidateRouteHop<'a>,
fee_msat: u64,
- /// Minimal fees required to route to the source node of the current hop via any of its inbound channels.
- src_lowest_inbound_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 candidate.fees()).
}
}
+#[inline(always)]
+/// Calculate the fees required to route the given amount over a channel with the given fees.
fn compute_fees(amount_msat: u64, channel_fees: RoutingFees) -> Option<u64> {
- let proportional_fee_millions =
- amount_msat.checked_mul(channel_fees.proportional_millionths as u64);
- if let Some(new_fee) = proportional_fee_millions.and_then(|part| {
- (channel_fees.base_msat as u64).checked_add(part / 1_000_000) }) {
+ amount_msat.checked_mul(channel_fees.proportional_millionths as u64)
+ .and_then(|part| (channel_fees.base_msat as u64).checked_add(part / 1_000_000))
+}
- Some(new_fee)
- } else {
- // This function may be (indirectly) called without any verification,
- // with channel_fees provided by a caller. We should handle it gracefully.
- None
- }
+#[inline(always)]
+/// Calculate the fees required to route the given amount over a channel with the given fees,
+/// saturating to [`u64::max_value`].
+fn compute_fees_saturating(amount_msat: u64, channel_fees: RoutingFees) -> u64 {
+ amount_msat.checked_mul(channel_fees.proportional_millionths as u64)
+ .map(|prop| prop / 1_000_000).unwrap_or(u64::max_value())
+ .saturating_add(channel_fees.base_msat as u64)
}
/// The default `features` we assume for a node in a route, when no `features` are known about that
// 8. If our maximum channel saturation limit caused us to pick two identical paths, combine
// them so that we're not sending two HTLCs along the same path.
- // As for the actual search algorithm,
- // we do a payee-to-payer pseudo-Dijkstra's sorting by each node's distance from the payee
- // plus the minimum per-HTLC fee to get from it to another node (aka "shitty pseudo-A*").
+ // As for the actual search algorithm, we do a payee-to-payer Dijkstra's sorting by each node's
+ // distance from the payee
//
// We are not a faithful Dijkstra's implementation because we can change values which impact
// earlier nodes while processing later nodes. Specifically, if we reach a channel with a lower
// runtime for little gain. Specifically, the current algorithm rather efficiently explores the
// graph for candidate paths, calculating the maximum value which can realistically be sent at
// the same time, remaining generic across different payment values.
- //
- // TODO: There are a few tweaks we could do, including possibly pre-calculating more stuff
- // to use as the A* heuristic beyond just the cost to get one node further than the current
- // one.
let network_channels = network_graph.channels();
let network_nodes = network_graph.nodes();
}
}
- // The main heap containing all candidate next-hops sorted by their score (max(A* fee,
+ // The main heap containing all candidate next-hops sorted by their score (max(fee,
// htlc_minimum)). Ideally this would be a heap which allowed cheap score reduction instead of
// adding duplicate entries when we find a better path to a given node.
let mut targets: BinaryHeap<RouteGraphNode> = BinaryHeap::new();
// might violate htlc_minimum_msat on the hops which are next along the
// payment path (upstream to the payee). To avoid that, we recompute
// path fees knowing the final path contribution after constructing it.
- let path_htlc_minimum_msat = compute_fees($next_hops_path_htlc_minimum_msat, $candidate.fees())
- .and_then(|fee_msat| fee_msat.checked_add($next_hops_path_htlc_minimum_msat))
- .map(|fee_msat| cmp::max(fee_msat, $candidate.htlc_minimum_msat()))
- .unwrap_or_else(|| u64::max_value());
+ let path_htlc_minimum_msat = cmp::max(
+ compute_fees_saturating($next_hops_path_htlc_minimum_msat, $candidate.fees())
+ .saturating_add($next_hops_path_htlc_minimum_msat),
+ $candidate.htlc_minimum_msat());
let hm_entry = dist.entry($src_node_id);
let old_entry = hm_entry.or_insert_with(|| {
// If there was previously no known way to access the source node
// semi-dummy record just to compute the fees to reach the source node.
// This will affect our decision on selecting short_channel_id
// as a way to reach the $dest_node_id.
- let mut fee_base_msat = 0;
- let mut fee_proportional_millionths = 0;
- if let Some(Some(fees)) = network_nodes.get(&$src_node_id).map(|node| node.lowest_inbound_channel_fees) {
- fee_base_msat = fees.base_msat;
- fee_proportional_millionths = fees.proportional_millionths;
- }
PathBuildingHop {
node_id: $dest_node_id.clone(),
candidate: $candidate.clone(),
fee_msat: 0,
- src_lowest_inbound_fees: RoutingFees {
- base_msat: fee_base_msat,
- proportional_millionths: fee_proportional_millionths,
- },
next_hops_fee_msat: u64::max_value(),
hop_use_fee_msat: u64::max_value(),
total_fee_msat: u64::max_value(),
if should_process {
let mut hop_use_fee_msat = 0;
- let mut total_fee_msat = $next_hops_fee_msat;
+ let mut total_fee_msat: u64 = $next_hops_fee_msat;
// Ignore hop_use_fee_msat for channel-from-us as we assume all channels-from-us
// will have the same effective-fee
if $src_node_id != our_node_id {
- match compute_fees(amount_to_transfer_over_msat, $candidate.fees()) {
- // max_value means we'll always fail
- // the old_entry.total_fee_msat > total_fee_msat check
- None => total_fee_msat = u64::max_value(),
- Some(fee_msat) => {
- hop_use_fee_msat = fee_msat;
- total_fee_msat += hop_use_fee_msat;
- // When calculating the lowest inbound fees to a node, we
- // calculate fees here not based on the actual value we think
- // will flow over this channel, but on the minimum value that
- // we'll accept flowing over it. The minimum accepted value
- // is a constant through each path collection run, ensuring
- // consistent basis. Otherwise we may later find a
- // different path to the source node that is more expensive,
- // but which we consider to be cheaper because we are capacity
- // constrained and the relative fee becomes lower.
- match compute_fees(minimal_value_contribution_msat, old_entry.src_lowest_inbound_fees)
- .map(|a| a.checked_add(total_fee_msat)) {
- Some(Some(v)) => {
- total_fee_msat = v;
- },
- _ => {
- total_fee_msat = u64::max_value();
- }
- };
- }
- }
+ // Note that `u64::max_value` means we'll always fail the
+ // `old_entry.total_fee_msat > total_fee_msat` check below
+ hop_use_fee_msat = compute_fees_saturating(amount_to_transfer_over_msat, $candidate.fees());
+ total_fee_msat = total_fee_msat.saturating_add(hop_use_fee_msat);
}
let channel_usage = ChannelUsage {
.saturating_add(channel_penalty_msat);
let new_graph_node = RouteGraphNode {
node_id: $src_node_id,
- lowest_fee_to_peer_through_node: total_fee_msat,
- lowest_fee_to_node: $next_hops_fee_msat as u64 + hop_use_fee_msat,
+ lowest_fee_to_node: total_fee_msat,
total_cltv_delta: hop_total_cltv_delta,
value_contribution_msat,
path_htlc_minimum_msat,
'load_endpoints: for _ in 0..10 {
loop {
seed = seed.overflowing_mul(0xdeadbeef).0;
- let src = &PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
+ let src = &PublicKey::from_slice(nodes.unordered_keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
seed = seed.overflowing_mul(0xdeadbeef).0;
- let dst = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
+ let dst = PublicKey::from_slice(nodes.unordered_keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
let payment_params = PaymentParameters::from_node_id(dst);
let amt = seed as u64 % 200_000_000;
let params = ProbabilisticScoringParameters::default();
'load_endpoints: for _ in 0..10 {
loop {
seed = seed.overflowing_mul(0xdeadbeef).0;
- let src = &PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
+ let src = &PublicKey::from_slice(nodes.unordered_keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
seed = seed.overflowing_mul(0xdeadbeef).0;
- let dst = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
+ let dst = PublicKey::from_slice(nodes.unordered_keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
let payment_params = PaymentParameters::from_node_id(dst).with_features(channelmanager::provided_invoice_features(&config));
let amt = seed as u64 % 200_000_000;
let params = ProbabilisticScoringParameters::default();
'load_endpoints: for _ in 0..150 {
loop {
seed *= 0xdeadbeef;
- let src = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
+ let src = PublicKey::from_slice(nodes.unordered_keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
seed *= 0xdeadbeef;
- let dst = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
+ let dst = PublicKey::from_slice(nodes.unordered_keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
let params = PaymentParameters::from_node_id(dst).with_features(features.clone());
let first_hop = first_hop(src);
let amt = seed as u64 % 1_000_000;