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)
- .checked_add(other.path_penalty_msat)
- .unwrap_or_else(|| u64::max_value());
+ .saturating_add(other.path_penalty_msat);
let self_score = cmp::max(self.lowest_fee_to_peer_through_node, self.path_htlc_minimum_msat)
- .checked_add(self.path_penalty_msat)
- .unwrap_or_else(|| u64::max_value());
+ .saturating_add(self.path_penalty_msat);
other_score.cmp(&self_score).then_with(|| other.node_id.cmp(&self.node_id))
}
}
self.hops.last().unwrap().0.fee_msat
}
+ fn get_path_penalty_msat(&self) -> u64 {
+ self.hops.first().map(|h| h.0.path_penalty_msat).unwrap_or(u64::max_value())
+ }
+
fn get_total_fee_paid_msat(&self) -> u64 {
if self.hops.len() < 1 {
return 0;
return result;
}
+ fn get_cost_msat(&self) -> u64 {
+ self.get_total_fee_paid_msat().saturating_add(self.get_path_penalty_msat())
+ }
+
// If the amount transferred by the path is updated, the fees should be adjusted. Any other way
// to change fees may result in an inconsistency.
//
}
}
+/// The default `features` we assume for a node in a route, when no `features` are known about that
+/// specific node.
+///
+/// Default features are:
+/// * variable_length_onion_optional
+fn default_node_features() -> NodeFeatures {
+ let mut features = NodeFeatures::empty();
+ features.set_variable_length_onion_optional();
+ features
+}
+
/// Finds a route from us (payer) to the given target node (payee).
///
/// If the payee provided features in their invoice, they should be provided via `params.payee`.
pub(crate) fn get_route<L: Deref, S: Score>(
our_node_pubkey: &PublicKey, payment_params: &PaymentParameters, network_graph: &ReadOnlyNetworkGraph,
first_hops: Option<&[&ChannelDetails]>, final_value_msat: u64, final_cltv_expiry_delta: u32,
- logger: L, scorer: &S, _random_seed_bytes: &[u8; 32]
+ logger: L, scorer: &S, random_seed_bytes: &[u8; 32]
) -> Result<Route, LightningError>
where L::Target: Logger {
let payee_node_id = NodeId::from_pubkey(&payment_params.payee_pubkey);
.entry(short_channel_id)
.or_insert_with(|| $candidate.effective_capacity().as_msat());
- // It is tricky to substract $next_hops_fee_msat from available liquidity here.
+ // It is tricky to subtract $next_hops_fee_msat from available liquidity here.
// It may be misleading because we might later choose to reduce the value transferred
// over these channels, and the channel which was insufficient might become sufficient.
// Worst case: we drop a good channel here because it can't cover the high following
.checked_sub(2*MEDIAN_HOP_CLTV_EXPIRY_DELTA)
.unwrap_or(payment_params.max_total_cltv_expiry_delta - final_cltv_expiry_delta);
let hop_total_cltv_delta = ($next_hops_cltv_delta as u32)
- .checked_add($candidate.cltv_expiry_delta())
- .unwrap_or(u32::max_value());
+ .saturating_add($candidate.cltv_expiry_delta());
let doesnt_exceed_cltv_delta_limit = hop_total_cltv_delta <= max_total_cltv_expiry_delta;
let value_contribution_msat = cmp::min(available_value_contribution_msat, $next_hops_value_contribution);
let over_path_minimum_msat = amount_to_transfer_over_msat >= $candidate.htlc_minimum_msat() &&
amount_to_transfer_over_msat >= $next_hops_path_htlc_minimum_msat;
+ #[allow(unused_comparisons)] // $next_hops_path_htlc_minimum_msat is 0 in some calls so rustc complains
+ let may_overpay_to_meet_path_minimum_msat =
+ ((amount_to_transfer_over_msat < $candidate.htlc_minimum_msat() &&
+ recommended_value_msat > $candidate.htlc_minimum_msat()) ||
+ (amount_to_transfer_over_msat < $next_hops_path_htlc_minimum_msat &&
+ recommended_value_msat > $next_hops_path_htlc_minimum_msat));
+
// If HTLC minimum is larger than the amount we're going to transfer, we shouldn't
- // bother considering this channel.
- // Since we're choosing amount_to_transfer_over_msat as maximum possible, it can
- // be only reduced later (not increased), so this channel should just be skipped
- // as not sufficient.
- if !over_path_minimum_msat && doesnt_exceed_cltv_delta_limit {
+ // bother considering this channel. If retrying with recommended_value_msat may
+ // allow us to hit the HTLC minimum limit, set htlc_minimum_limit so that we go
+ // around again with a higher amount.
+ if contributes_sufficient_value && doesnt_exceed_cltv_delta_limit && may_overpay_to_meet_path_minimum_msat {
hit_minimum_limit = true;
- } else if contributes_sufficient_value && doesnt_exceed_cltv_delta_limit {
+ } else if contributes_sufficient_value && doesnt_exceed_cltv_delta_limit && over_path_minimum_msat {
// Note that low contribution here (limited by available_liquidity_msat)
// might violate htlc_minimum_msat on the hops which are next along the
// payment path (upstream to the payee). To avoid that, we recompute
}
}
- let path_penalty_msat = $next_hops_path_penalty_msat.checked_add(
- scorer.channel_penalty_msat(short_channel_id, amount_to_transfer_over_msat, *available_liquidity_msat,
- &$src_node_id, &$dest_node_id)).unwrap_or_else(|| u64::max_value());
+ let path_penalty_msat = $next_hops_path_penalty_msat.saturating_add(
+ scorer.channel_penalty_msat(short_channel_id, amount_to_transfer_over_msat,
+ *available_liquidity_msat, &$src_node_id, &$dest_node_id));
let new_graph_node = RouteGraphNode {
node_id: $src_node_id,
lowest_fee_to_peer_through_node: total_fee_msat,
// the fees included in $next_hops_path_htlc_minimum_msat, but also
// can't use something that may decrease on future hops.
let old_cost = cmp::max(old_entry.total_fee_msat, old_entry.path_htlc_minimum_msat)
- .checked_add(old_entry.path_penalty_msat)
- .unwrap_or_else(|| u64::max_value());
+ .saturating_add(old_entry.path_penalty_msat);
let new_cost = cmp::max(total_fee_msat, path_htlc_minimum_msat)
- .checked_add(path_penalty_msat)
- .unwrap_or_else(|| u64::max_value());
+ .saturating_add(path_penalty_msat);
if !old_entry.was_processed && new_cost < old_cost {
targets.push(new_graph_node);
} }
}
- let empty_node_features = NodeFeatures::empty();
+ let default_node_features = default_node_features();
+
// Find ways (channels with destination) to reach a given node and store them
// in the corresponding data structures (routing graph etc).
// $fee_to_target_msat represents how much it costs to reach to this node from the payee,
let features = if let Some(node_info) = $node.announcement_info.as_ref() {
&node_info.features
} else {
- &empty_node_features
+ &default_node_features
};
if !features.requires_unknown_bits() {
.unwrap_or_else(|| CandidateRouteHop::PrivateHop { hint: hop });
let capacity_msat = candidate.effective_capacity().as_msat();
aggregate_next_hops_path_penalty_msat = aggregate_next_hops_path_penalty_msat
- .checked_add(scorer.channel_penalty_msat(hop.short_channel_id, final_value_msat, capacity_msat, &source, &target))
- .unwrap_or_else(|| u64::max_value());
+ .saturating_add(scorer.channel_penalty_msat(hop.short_channel_id, final_value_msat, capacity_msat, &source, &target));
aggregate_next_hops_cltv_delta = aggregate_next_hops_cltv_delta
- .checked_add(hop.cltv_expiry_delta as u32)
- .unwrap_or_else(|| u32::max_value());
+ .saturating_add(hop.cltv_expiry_delta as u32);
if !add_entry!(candidate, source, target, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta) {
// If this hop was not used then there is no use checking the preceding hops
// traversing the graph and arrange the path out of what we found.
if node_id == our_node_id {
let mut new_entry = dist.remove(&our_node_id).unwrap();
- let mut ordered_hops = vec!((new_entry.clone(), NodeFeatures::empty()));
+ let mut ordered_hops = vec!((new_entry.clone(), default_node_features.clone()));
'path_walk: loop {
let mut features_set = false;
if let Some(node_info) = node.announcement_info.as_ref() {
ordered_hops.last_mut().unwrap().1 = node_info.features.clone();
} else {
- ordered_hops.last_mut().unwrap().1 = NodeFeatures::empty();
+ ordered_hops.last_mut().unwrap().1 = default_node_features.clone();
}
} else {
// We can fill in features for everything except hops which were
// 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.push((new_entry.clone(), NodeFeatures::empty()));
+ ordered_hops.push((new_entry.clone(), default_node_features.clone()));
}
ordered_hops.last_mut().unwrap().0.fee_msat = value_contribution_msat;
ordered_hops.last_mut().unwrap().0.hop_use_fee_msat = 0;
// 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.candidate.short_channel_id();
+ let victim_scid = payment_path.hops[(payment_path.hops.len()) / 2].0.candidate.short_channel_id();
log_trace!(logger, "Disabling channel {} for future path building iterations to avoid duplicates.", victim_scid);
let victim_liquidity = bookkept_channels_liquidity_available_msat.get_mut(&victim_scid).unwrap();
*victim_liquidity = 0;
}
// Sort by total fees and take the best paths.
- payment_paths.sort_by_key(|path| path.get_total_fee_paid_msat());
+ payment_paths.sort_unstable_by_key(|path| path.get_total_fee_paid_msat());
if payment_paths.len() > 50 {
payment_paths.truncate(50);
}
// Draw multiple sufficient routes by randomly combining the selected paths.
let mut drawn_routes = Vec::new();
- for i in 0..payment_paths.len() {
+ let mut prng = ChaCha20::new(random_seed_bytes, &[0u8; 12]);
+ let mut random_index_bytes = [0u8; ::core::mem::size_of::<usize>()];
+
+ let num_permutations = payment_paths.len();
+ for _ in 0..num_permutations {
let mut cur_route = Vec::<PaymentPath>::new();
let mut aggregate_route_value_msat = 0;
// Step (6).
- // TODO: real random shuffle
- // Currently just starts with i_th and goes up to i-1_th in a looped way.
- let cur_payment_paths = [&payment_paths[i..], &payment_paths[..i]].concat();
+ // Do a Fisher-Yates shuffle to create a random permutation of the payment paths
+ for cur_index in (1..payment_paths.len()).rev() {
+ prng.process_in_place(&mut random_index_bytes);
+ let random_index = usize::from_be_bytes(random_index_bytes).wrapping_rem(cur_index+1);
+ payment_paths.swap(cur_index, random_index);
+ }
// Step (7).
- for payment_path in cur_payment_paths {
+ for payment_path in &payment_paths {
cur_route.push(payment_path.clone());
aggregate_route_value_msat += payment_path.get_value_msat();
if aggregate_route_value_msat > final_value_msat {
// also makes routing more reliable.
let mut overpaid_value_msat = aggregate_route_value_msat - final_value_msat;
- // First, drop some expensive low-value paths entirely if possible.
- // Sort by value so that we drop many really-low values first, since
- // fewer paths is better: the payment is less likely to fail.
- // 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.get_value_msat());
+ // First, we drop some expensive low-value paths entirely if possible, since fewer
+ // paths is better: the payment is less likely to fail. In order to do so, we sort
+ // by value and fall back to total fees paid, i.e., in case of equal values we
+ // prefer lower cost paths.
+ cur_route.sort_unstable_by(|a, b| {
+ a.get_value_msat().cmp(&b.get_value_msat())
+ // Reverse ordering for cost, so we drop higher-cost paths first
+ .then_with(|| b.get_cost_msat().cmp(&a.get_cost_msat()))
+ });
+
// We should make sure that at least 1 path left.
let mut paths_left = cur_route.len();
cur_route.retain(|path| {
assert!(cur_route.len() > 0);
// Step (8).
- // Now, substract the overpaid value from the most-expensive path.
+ // Now, subtract 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.candidate.fees().proportional_millionths as u64).sum::<u64>() });
+ cur_route.sort_unstable_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.
+
+ // We already dropped all the small value paths above, meaning all the
+ // remaining paths are larger than remaining overpaid_value_msat.
// Thus, this can't be negative.
let expensive_path_new_value_msat = expensive_payment_path.get_value_msat() - overpaid_value_msat;
expensive_payment_path.update_value_and_recompute_fees(expensive_path_new_value_msat);
}
// Step (9).
- // Select the best route by lowest total fee.
- drawn_routes.sort_by_key(|paths| paths.iter().map(|path| path.get_total_fee_paid_msat()).sum::<u64>());
+ // Select the best route by lowest total cost.
+ drawn_routes.sort_unstable_by_key(|paths| paths.iter().map(|path| path.get_cost_msat()).sum::<u64>());
let mut selected_paths = Vec::<Vec<Result<RouteHop, LightningError>>>::new();
for payment_path in drawn_routes.first().unwrap() {
let mut path = payment_path.hops.iter().map(|(payment_hop, node_features)| {
#[cfg(test)]
mod tests {
use routing::network_graph::{NetworkGraph, NetGraphMsgHandler, NodeId};
- use routing::router::{get_route, add_random_cltv_offset, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees, DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA};
+ use routing::router::{get_route, add_random_cltv_offset, default_node_features, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees, DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA};
use routing::scoring::Score;
use chain::transaction::OutPoint;
use chain::keysinterface::KeysInterface;
node_id,
unspendable_punishment_reserve: 0,
forwarding_info: None,
+ outbound_htlc_minimum_msat: None,
+ outbound_htlc_maximum_msat: None,
},
funding_txo: Some(OutPoint { txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0 }),
+ channel_type: None,
short_channel_id,
inbound_scid_alias: None,
channel_value_satoshis: 0,
force_close_spend_delay: None,
is_outbound: true, is_funding_locked: true,
is_usable: true, is_public: true,
+ inbound_htlc_minimum_msat: None,
+ inbound_htlc_maximum_msat: None,
}
}
assert_eq!(route.paths[0][4].short_channel_id, 8);
assert_eq!(route.paths[0][4].fee_msat, 100);
assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][4].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
}
assert_eq!(route.paths[0][4].short_channel_id, 8);
assert_eq!(route.paths[0][4].fee_msat, 100);
assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][4].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
}
assert_eq!(route.paths[0][3].short_channel_id, last_hops[0].0[1].short_channel_id);
assert_eq!(route.paths[0][3].fee_msat, 100);
assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][3].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
}
assert_eq!(route.paths[0][2].short_channel_id, last_hops[0].0[0].short_channel_id);
assert_eq!(route.paths[0][2].fee_msat, 0);
assert_eq!(route.paths[0][2].cltv_expiry_delta, 129);
- assert_eq!(route.paths[0][2].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][2].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][2].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
assert_eq!(route.paths[0][3].pubkey, nodes[6]);
assert_eq!(route.paths[0][3].short_channel_id, last_hops[0].0[1].short_channel_id);
assert_eq!(route.paths[0][3].fee_msat, 100);
assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][3].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
}
assert_eq!(route.paths[0][4].short_channel_id, 8);
assert_eq!(route.paths[0][4].fee_msat, 100);
assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][4].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
}
assert_eq!(route.paths[0][1].short_channel_id, 8);
assert_eq!(route.paths[0][1].fee_msat, 100);
assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][1].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][1].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][1].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
last_hops[0].0[0].fees.base_msat = 1000;
assert_eq!(route.paths[0][3].short_channel_id, 10);
assert_eq!(route.paths[0][3].fee_msat, 100);
assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][3].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
// ...but still use 8 for larger payments as 6 has a variable feerate
assert_eq!(route.paths[0][4].short_channel_id, 8);
assert_eq!(route.paths[0][4].fee_msat, 2000);
assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][4].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
}
assert_eq!(route.paths[0][1].short_channel_id, 8);
assert_eq!(route.paths[0][1].fee_msat, 1000000);
assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
- assert_eq!(route.paths[0][1].node_features.le_flags(), &[0; 0]); // We dont pass flags in from invoices yet
+ assert_eq!(route.paths[0][1].node_features.le_flags(), default_node_features().le_flags()); // We dont pass flags in from invoices yet
assert_eq!(route.paths[0][1].channel_features.le_flags(), &[0; 0]); // We can't learn any flags from invoices, sadly
}
node_id,
unspendable_punishment_reserve: 0,
forwarding_info: None,
+ outbound_htlc_minimum_msat: None,
+ outbound_htlc_maximum_msat: None,
},
funding_txo: Some(OutPoint {
txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0
}),
+ channel_type: None,
short_channel_id: Some(1),
inbound_scid_alias: None,
channel_value_satoshis: 10_000_000,
is_funding_locked: true,
is_usable: true,
is_public: true,
+ inbound_htlc_minimum_msat: None,
+ inbound_htlc_maximum_msat: None,
}
}
projects / rust-lightning / blobdiff