use ln::channelmanager::ChannelDetails;
use ln::features::{ChannelFeatures, InvoiceFeatures, NodeFeatures};
use ln::msgs::{DecodeError, ErrorAction, LightningError, MAX_VALUE_MSAT};
-use routing::scoring::Score;
+use routing::scoring::{ChannelUsage, Score};
use routing::network_graph::{DirectedChannelInfoWithUpdate, EffectiveCapacity, NetworkGraph, ReadOnlyNetworkGraph, NodeId, RoutingFees};
-use util::ser::{Writeable, Readable};
+use util::ser::{Writeable, Readable, Writer};
use util::logger::{Level, Logger};
use util::chacha20::ChaCha20;
/// Parameters needed to find a [`Route`].
///
-/// Passed to [`find_route`] and also provided in [`Event::PaymentPathFailed`] for retrying a failed
-/// payment path.
+/// Passed to [`find_route`] and [`build_route_from_hops`], but also provided in
+/// [`Event::PaymentPathFailed`] for retrying a failed payment path.
///
/// [`Event::PaymentPathFailed`]: crate::util::events::Event::PaymentPathFailed
#[derive(Clone, Debug)]
impl<'a> CandidateRouteHop<'a> {
fn short_channel_id(&self) -> u64 {
match self {
- CandidateRouteHop::FirstHop { details } => details.short_channel_id.unwrap(),
+ CandidateRouteHop::FirstHop { details } => details.get_outbound_payment_scid().unwrap(),
CandidateRouteHop::PublicHop { short_channel_id, .. } => *short_channel_id,
CandidateRouteHop::PrivateHop { hint } => hint.short_channel_id,
}
}
}
+ fn htlc_maximum_msat(&self) -> u64 {
+ match self {
+ CandidateRouteHop::FirstHop { details } => details.next_outbound_htlc_limit_msat,
+ CandidateRouteHop::PublicHop { info, .. } => info.htlc_maximum_msat(),
+ CandidateRouteHop::PrivateHop { hint } => {
+ hint.htlc_maximum_msat.unwrap_or(u64::max_value())
+ },
+ }
+ }
+
fn fees(&self) -> RoutingFees {
match self {
CandidateRouteHop::FirstHop { .. } => RoutingFees {
) -> Result<Route, LightningError>
where L::Target: Logger {
let network_graph = network.read_only();
- match get_route(
- our_node_pubkey, &route_params.payment_params, &network_graph, first_hops, route_params.final_value_msat,
- route_params.final_cltv_expiry_delta, logger, scorer, random_seed_bytes
- ) {
- Ok(mut route) => {
- add_random_cltv_offset(&mut route, &route_params.payment_params, &network_graph, random_seed_bytes);
- Ok(route)
- },
- Err(err) => Err(err),
- }
+ let mut route = get_route(our_node_pubkey, &route_params.payment_params, &network_graph, first_hops,
+ route_params.final_value_msat, route_params.final_cltv_expiry_delta, logger, scorer,
+ random_seed_bytes)?;
+ add_random_cltv_offset(&mut route, &route_params.payment_params, &network_graph, random_seed_bytes);
+ Ok(route)
}
pub(crate) fn get_route<L: Deref, S: Score>(
HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
if let Some(hops) = first_hops {
for chan in hops {
- if chan.short_channel_id.is_none() {
+ if chan.get_outbound_payment_scid().is_none() {
panic!("first_hops should be filled in with usable channels, not pending ones");
}
if chan.counterparty.node_id == *our_node_pubkey {
let recommended_value_msat = final_value_msat * ROUTE_CAPACITY_PROVISION_FACTOR as u64;
let mut path_value_msat = final_value_msat;
- // We don't want multiple paths (as per MPP) share liquidity of the same channels.
- // This map allows paths to be aware of the channel use by other paths in the same call.
- // This would help to make a better path finding decisions and not "overbook" channels.
- // It is unaware of the directions (except for `next_outbound_htlc_limit_msat` in
- // `first_hops`).
- let mut bookkept_channels_liquidity_available_msat = HashMap::with_capacity(network_nodes.len());
+ // Keep track of how much liquidity has been used in selected channels. Used to determine
+ // if the channel can be used by additional MPP paths or to inform path finding decisions. It is
+ // aware of direction *only* to ensure that the correct htlc_maximum_msat value is used. Hence,
+ // liquidity used in one direction will not offset any used in the opposite direction.
+ let mut used_channel_liquidities: HashMap<(u64, bool), u64> =
+ HashMap::with_capacity(network_nodes.len());
// Keeping track of how much value we already collected across other paths. Helps to decide:
// - how much a new path should be transferring (upper bound);
// - for first and last hops early in get_route
if $src_node_id != $dest_node_id {
let short_channel_id = $candidate.short_channel_id();
- let available_liquidity_msat = bookkept_channels_liquidity_available_msat
- .entry(short_channel_id)
- .or_insert_with(|| $candidate.effective_capacity().as_msat());
+ let htlc_maximum_msat = $candidate.htlc_maximum_msat();
// It is tricky to subtract $next_hops_fee_msat from available liquidity here.
// It may be misleading because we might later choose to reduce the value transferred
// fees caused by one expensive channel, but then this channel could have been used
// if the amount being transferred over this path is lower.
// We do this for now, but this is a subject for removal.
- if let Some(available_value_contribution_msat) = available_liquidity_msat.checked_sub($next_hops_fee_msat) {
+ if let Some(mut available_value_contribution_msat) = htlc_maximum_msat.checked_sub($next_hops_fee_msat) {
+ let used_liquidity_msat = used_channel_liquidities
+ .get(&(short_channel_id, $src_node_id < $dest_node_id))
+ .map_or(0, |used_liquidity_msat| {
+ available_value_contribution_msat = available_value_contribution_msat
+ .saturating_sub(*used_liquidity_msat);
+ *used_liquidity_msat
+ });
// Routing Fragmentation Mitigation heuristic:
//
}
}
- 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 channel_usage = ChannelUsage {
+ amount_msat: amount_to_transfer_over_msat,
+ inflight_htlc_msat: used_liquidity_msat,
+ effective_capacity: $candidate.effective_capacity(),
+ };
+ let channel_penalty_msat = scorer.channel_penalty_msat(
+ short_channel_id, &$src_node_id, &$dest_node_id, channel_usage
+ );
+ let path_penalty_msat = $next_hops_path_penalty_msat
+ .saturating_add(channel_penalty_msat);
let new_graph_node = RouteGraphNode {
node_id: $src_node_id,
lowest_fee_to_peer_through_node: total_fee_msat,
// TODO: diversify by nodes (so that all paths aren't doomed if one node is offline).
'paths_collection: loop {
- // For every new path, start from scratch, except
- // bookkept_channels_liquidity_available_msat, which will improve
- // the further iterations of path finding. Also don't erase first_hop_targets.
+ // For every new path, start from scratch, except for used_channel_liquidities, which
+ // helps to avoid reusing previously selected paths in future iterations.
targets.clear();
dist.clear();
hit_minimum_limit = false;
short_channel_id: hop.short_channel_id,
})
.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
- .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
- .saturating_add(hop.cltv_expiry_delta as u32);
-
- aggregate_next_hops_path_length = aggregate_next_hops_path_length
- .saturating_add(1);
if !add_entry!(candidate, source, target, aggregate_next_hops_fee_msat,
path_value_msat, aggregate_next_hops_path_htlc_minimum_msat,
hop_used = false;
}
+ let used_liquidity_msat = used_channel_liquidities
+ .get(&(hop.short_channel_id, source < target)).copied().unwrap_or(0);
+ let channel_usage = ChannelUsage {
+ amount_msat: final_value_msat + aggregate_next_hops_fee_msat,
+ inflight_htlc_msat: used_liquidity_msat,
+ effective_capacity: candidate.effective_capacity(),
+ };
+ let channel_penalty_msat = scorer.channel_penalty_msat(
+ hop.short_channel_id, &source, &target, channel_usage
+ );
+ aggregate_next_hops_path_penalty_msat = aggregate_next_hops_path_penalty_msat
+ .saturating_add(channel_penalty_msat);
+
+ aggregate_next_hops_cltv_delta = aggregate_next_hops_cltv_delta
+ .saturating_add(hop.cltv_expiry_delta as u32);
+
+ aggregate_next_hops_path_length = aggregate_next_hops_path_length
+ .saturating_add(1);
+
// Searching for a direct channel between last checked hop and first_hop_targets
if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&prev_hop_id)) {
for details in first_channels {
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.candidate.short_channel_id() {
+ if details.get_outbound_payment_scid().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;
// Remember that we used these channels so that we don't rely
// 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 = bookkept_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 spent_on_hop_msat == *channel_liquidity_available_msat {
+ let prev_hop_iter = core::iter::once(&our_node_id)
+ .chain(payment_path.hops.iter().map(|(hop, _)| &hop.node_id));
+ for (prev_hop, (hop, _)) in prev_hop_iter.zip(payment_path.hops.iter()) {
+ let spent_on_hop_msat = value_contribution_msat + hop.next_hops_fee_msat;
+ let used_liquidity_msat = used_channel_liquidities
+ .entry((hop.candidate.short_channel_id(), *prev_hop < hop.node_id))
+ .and_modify(|used_liquidity_msat| *used_liquidity_msat += spent_on_hop_msat)
+ .or_insert(spent_on_hop_msat);
+ if *used_liquidity_msat == hop.candidate.htlc_maximum_msat() {
// If this path used all of this channel's available liquidity, we know
// this path will not be selected again in the next loop iteration.
prevented_redundant_path_selection = true;
}
- *channel_liquidity_available_msat -= spent_on_hop_msat;
+ debug_assert!(*used_liquidity_msat <= hop.candidate.htlc_maximum_msat());
}
if !prevented_redundant_path_selection {
// 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()) / 2].0.candidate.short_channel_id();
+ let exhausted = u64::max_value();
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;
+ *used_channel_liquidities.entry((victim_scid, false)).or_default() = exhausted;
+ *used_channel_liquidities.entry((victim_scid, true)).or_default() = exhausted;
}
// Track the total amount all our collected paths allow to send so that we:
// destination, if the remaining CLTV expiry delta exactly matches a feasible path in the network
// graph. In order to improve privacy, this method obfuscates the CLTV expiry deltas along the
// payment path by adding a randomized 'shadow route' offset to the final hop.
-fn add_random_cltv_offset(route: &mut Route, payment_params: &PaymentParameters, network_graph: &ReadOnlyNetworkGraph, random_seed_bytes: &[u8; 32]) {
+fn add_random_cltv_offset(route: &mut Route, payment_params: &PaymentParameters,
+ network_graph: &ReadOnlyNetworkGraph, random_seed_bytes: &[u8; 32]
+) {
let network_channels = network_graph.channels();
let network_nodes = network_graph.nodes();
}
}
+/// Construct a route from us (payer) to the target node (payee) via the given hops (which should
+/// exclude the payer, but include the payee). This may be useful, e.g., for probing the chosen path.
+///
+/// Re-uses logic from `find_route`, so the restrictions described there also apply here.
+pub fn build_route_from_hops<L: Deref>(
+ our_node_pubkey: &PublicKey, hops: &[PublicKey], route_params: &RouteParameters, network: &NetworkGraph,
+ logger: L, random_seed_bytes: &[u8; 32]
+) -> Result<Route, LightningError>
+where L::Target: Logger {
+ let network_graph = network.read_only();
+ let mut route = build_route_from_hops_internal(
+ our_node_pubkey, hops, &route_params.payment_params, &network_graph,
+ route_params.final_value_msat, route_params.final_cltv_expiry_delta, logger, random_seed_bytes)?;
+ add_random_cltv_offset(&mut route, &route_params.payment_params, &network_graph, random_seed_bytes);
+ Ok(route)
+}
+
+fn build_route_from_hops_internal<L: Deref>(
+ our_node_pubkey: &PublicKey, hops: &[PublicKey], payment_params: &PaymentParameters,
+ network_graph: &ReadOnlyNetworkGraph, final_value_msat: u64, final_cltv_expiry_delta: u32,
+ logger: L, random_seed_bytes: &[u8; 32]
+) -> Result<Route, LightningError> where L::Target: Logger {
+
+ struct HopScorer {
+ our_node_id: NodeId,
+ hop_ids: [Option<NodeId>; MAX_PATH_LENGTH_ESTIMATE as usize],
+ }
+
+ impl Score for HopScorer {
+ fn channel_penalty_msat(&self, _short_channel_id: u64, source: &NodeId, target: &NodeId,
+ _usage: ChannelUsage) -> u64
+ {
+ let mut cur_id = self.our_node_id;
+ for i in 0..self.hop_ids.len() {
+ if let Some(next_id) = self.hop_ids[i] {
+ if cur_id == *source && next_id == *target {
+ return 0;
+ }
+ cur_id = next_id;
+ } else {
+ break;
+ }
+ }
+ u64::max_value()
+ }
+
+ fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
+
+ fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
+ }
+
+ impl<'a> Writeable for HopScorer {
+ #[inline]
+ fn write<W: Writer>(&self, _w: &mut W) -> Result<(), io::Error> {
+ unreachable!();
+ }
+ }
+
+ if hops.len() > MAX_PATH_LENGTH_ESTIMATE.into() {
+ return Err(LightningError{err: "Cannot build a route exceeding the maximum path length.".to_owned(), action: ErrorAction::IgnoreError});
+ }
+
+ let our_node_id = NodeId::from_pubkey(our_node_pubkey);
+ let mut hop_ids = [None; MAX_PATH_LENGTH_ESTIMATE as usize];
+ for i in 0..hops.len() {
+ hop_ids[i] = Some(NodeId::from_pubkey(&hops[i]));
+ }
+
+ let scorer = HopScorer { our_node_id, hop_ids };
+
+ get_route(our_node_pubkey, payment_params, network_graph, None, final_value_msat,
+ final_cltv_expiry_delta, logger, &scorer, random_seed_bytes)
+}
+
#[cfg(test)]
mod tests {
use routing::network_graph::{NetworkGraph, NetGraphMsgHandler, NodeId};
- use routing::router::{get_route, add_random_cltv_offset, default_node_features,
+ use routing::router::{get_route, build_route_from_hops_internal, add_random_cltv_offset, default_node_features,
PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees,
DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE};
- use routing::scoring::Score;
+ use routing::scoring::{ChannelUsage, Score};
use chain::transaction::OutPoint;
use chain::keysinterface::KeysInterface;
use ln::features::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
funding_txo: Some(OutPoint { txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0 }),
channel_type: None,
short_channel_id,
+ outbound_scid_alias: None,
inbound_scid_alias: None,
channel_value_satoshis: 0,
user_channel_id: 0,
unspendable_punishment_reserve: None,
confirmations_required: None,
force_close_spend_delay: None,
- is_outbound: true, is_funding_locked: true,
+ is_outbound: true, is_channel_ready: true,
is_usable: true, is_public: true,
inbound_htlc_minimum_msat: None,
inbound_htlc_maximum_msat: None,
fn write<W: Writer>(&self, _w: &mut W) -> Result<(), ::io::Error> { unimplemented!() }
}
impl Score for BadChannelScorer {
- fn channel_penalty_msat(&self, short_channel_id: u64, _send_amt: u64, _capacity_msat: u64, _source: &NodeId, _target: &NodeId) -> u64 {
+ fn channel_penalty_msat(&self, short_channel_id: u64, _: &NodeId, _: &NodeId, _: ChannelUsage) -> u64 {
if short_channel_id == self.short_channel_id { u64::max_value() } else { 0 }
}
}
impl Score for BadNodeScorer {
- fn channel_penalty_msat(&self, _short_channel_id: u64, _send_amt: u64, _capacity_msat: u64, _source: &NodeId, target: &NodeId) -> u64 {
+ fn channel_penalty_msat(&self, _: u64, _: &NodeId, target: &NodeId, _: ChannelUsage) -> u64 {
if *target == self.node_id { u64::max_value() } else { 0 }
}
assert!(path_plausibility.iter().all(|x| *x));
}
+ #[test]
+ fn builds_correct_path_from_hops() {
+ let (secp_ctx, network, _, _, logger) = build_graph();
+ let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
+ let network_graph = network.read_only();
+
+ let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
+ let random_seed_bytes = keys_manager.get_secure_random_bytes();
+
+ let payment_params = PaymentParameters::from_node_id(nodes[3]);
+ let hops = [nodes[1], nodes[2], nodes[4], nodes[3]];
+ let route = build_route_from_hops_internal(&our_id, &hops, &payment_params,
+ &network_graph, 100, 0, Arc::clone(&logger), &random_seed_bytes).unwrap();
+ let route_hop_pubkeys = route.paths[0].iter().map(|hop| hop.pubkey).collect::<Vec<_>>();
+ assert_eq!(hops.len(), route.paths[0].len());
+ for (idx, hop_pubkey) in hops.iter().enumerate() {
+ assert!(*hop_pubkey == route_hop_pubkeys[idx]);
+ }
+ }
+
#[cfg(not(feature = "no-std"))]
pub(super) fn random_init_seed() -> u64 {
// Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG.
channel_type: None,
short_channel_id: Some(1),
inbound_scid_alias: None,
+ outbound_scid_alias: None,
channel_value_satoshis: 10_000_000,
user_channel_id: 0,
balance_msat: 10_000_000,
confirmations_required: None,
force_close_spend_delay: None,
is_outbound: true,
- is_funding_locked: true,
+ is_channel_ready: true,
is_usable: true,
is_public: true,
inbound_htlc_minimum_msat: None,
projects / rust-lightning / blobdiff