use util::ser::{Writeable, Readable};
use util::logger::Logger;
-use std::cmp;
-use std::collections::{HashMap, BinaryHeap};
-use std::ops::Deref;
+use io;
+use prelude::*;
+use alloc::collections::BinaryHeap;
+use core::cmp;
+use core::ops::Deref;
/// A hop in a route
#[derive(Clone, PartialEq)]
pub cltv_expiry_delta: u32,
}
-/// (C-not exported)
-impl Writeable for Vec<RouteHop> {
- fn write<W: ::util::ser::Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
- (self.len() as u8).write(writer)?;
- for hop in self.iter() {
- hop.pubkey.write(writer)?;
- hop.node_features.write(writer)?;
- hop.short_channel_id.write(writer)?;
- hop.channel_features.write(writer)?;
- hop.fee_msat.write(writer)?;
- hop.cltv_expiry_delta.write(writer)?;
- }
- Ok(())
- }
-}
-
-/// (C-not exported)
-impl Readable for Vec<RouteHop> {
- fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Vec<RouteHop>, DecodeError> {
- let hops_count: u8 = Readable::read(reader)?;
- let mut hops = Vec::with_capacity(hops_count as usize);
- for _ in 0..hops_count {
- hops.push(RouteHop {
- pubkey: Readable::read(reader)?,
- node_features: Readable::read(reader)?,
- short_channel_id: Readable::read(reader)?,
- channel_features: Readable::read(reader)?,
- fee_msat: Readable::read(reader)?,
- cltv_expiry_delta: Readable::read(reader)?,
- });
- }
- Ok(hops)
- }
-}
+impl_writeable_tlv_based!(RouteHop, {
+ (0, pubkey, required),
+ (2, node_features, required),
+ (4, short_channel_id, required),
+ (6, channel_features, required),
+ (8, fee_msat, required),
+ (10, cltv_expiry_delta, required),
+});
/// A route directs a payment from the sender (us) to the recipient. If the recipient supports MPP,
/// it can take multiple paths. Each path is composed of one or more hops through the network.
pub paths: Vec<Vec<RouteHop>>,
}
+const SERIALIZATION_VERSION: u8 = 1;
+const MIN_SERIALIZATION_VERSION: u8 = 1;
+
impl Writeable for Route {
- fn write<W: ::util::ser::Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+ fn write<W: ::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+ write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
(self.paths.len() as u64).write(writer)?;
for hops in self.paths.iter() {
- hops.write(writer)?;
+ (hops.len() as u8).write(writer)?;
+ for hop in hops.iter() {
+ hop.write(writer)?;
+ }
}
+ write_tlv_fields!(writer, {});
Ok(())
}
}
impl Readable for Route {
- fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Route, DecodeError> {
+ fn read<R: io::Read>(reader: &mut R) -> Result<Route, DecodeError> {
+ let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
let path_count: u64 = Readable::read(reader)?;
let mut paths = Vec::with_capacity(cmp::min(path_count, 128) as usize);
for _ in 0..path_count {
- paths.push(Readable::read(reader)?);
+ let hop_count: u8 = Readable::read(reader)?;
+ let mut hops = Vec::with_capacity(hop_count as usize);
+ for _ in 0..hop_count {
+ hops.push(Readable::read(reader)?);
+ }
+ paths.push(hops);
}
+ read_tlv_fields!(reader, {});
Ok(Route { paths })
}
}
-/// A channel descriptor which provides a last-hop route to get_route
-#[derive(Clone)]
-pub struct RouteHint {
+/// A list of hops along a payment path terminating with a channel to the recipient.
+#[derive(Eq, PartialEq, Debug, Clone)]
+pub struct RouteHint(pub Vec<RouteHintHop>);
+
+/// A channel descriptor for a hop along a payment path.
+#[derive(Eq, PartialEq, Debug, Clone)]
+pub struct RouteHintHop {
/// The node_id of the non-target end of the route
pub src_node_id: PublicKey,
/// The short_channel_id of this channel
// - how much is needed for a path being constructed
// - how much value can channels following this node (up to the destination) can contribute,
// considering their capacity and fees
- value_contribution_msat: u64
+ value_contribution_msat: u64,
+ /// The effective htlc_minimum_msat at this hop. If a later hop on the path had a higher HTLC
+ /// minimum, we use it, plus the fees required at each earlier hop to meet it.
+ path_htlc_minimum_msat: u64,
}
impl cmp::Ord for RouteGraphNode {
fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering {
- other.lowest_fee_to_peer_through_node.cmp(&self.lowest_fee_to_peer_through_node)
- .then_with(|| other.pubkey.serialize().cmp(&self.pubkey.serialize()))
+ let other_score = cmp::max(other.lowest_fee_to_peer_through_node, other.path_htlc_minimum_msat);
+ let self_score = cmp::max(self.lowest_fee_to_peer_through_node, self.path_htlc_minimum_msat);
+ other_score.cmp(&self_score).then_with(|| other.pubkey.serialize().cmp(&self.pubkey.serialize()))
}
}
/// so that we can choose cheaper paths (as per Dijkstra's algorithm).
/// 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)]
-struct PathBuildingHop {
- /// Hop-specific details unrelated to the path during the routing phase,
- /// but rather relevant to the LN graph.
- route_hop: RouteHop,
+#[derive(Clone, Debug)]
+struct PathBuildingHop<'a> {
+ // 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.
+ pubkey: PublicKey,
+ short_channel_id: u64,
+ channel_features: &'a ChannelFeatures,
+ 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.
/// 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,
+ /// If we've already processed a node as the best node, we shouldn't process it again. Normally
+ /// we'd just ignore it if we did as all channels would have a higher new fee, but because we
+ /// may decrease the amounts in use as we walk the graph, the actual calculated fee may
+ /// decrease as well. Thus, we have to explicitly track which nodes have been processed and
+ /// avoid processing them again.
+ was_processed: bool,
+ #[cfg(any(test, feature = "fuzztarget"))]
+ // In tests, we apply further sanity checks on cases where we skip nodes we already processed
+ // to ensure it is specifically in cases where the fee has gone down because of a decrease in
+ // value_contribution_msat, which requires tracking it here. See comments below where it is
+ // used for more info.
+ value_contribution_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>,
+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().route_hop.fee_msat
+ self.hops.last().unwrap().0.fee_msat
}
fn get_total_fee_paid_msat(&self) -> u64 {
}
let mut result = 0;
// Can't use next_hops_fee_msat because it gets outdated.
- for (i, hop) in self.hops.iter().enumerate() {
+ for (i, (hop, _)) in self.hops.iter().enumerate() {
if i != self.hops.len() - 1 {
- result += hop.route_hop.fee_msat;
+ result += hop.fee_msat;
}
}
return result;
// 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.
//
- // Sometimes we call this function right after constructing a path which has inconsistent
- // (in terms of reaching htlc_minimum_msat), so that this function puts the fees in order.
- // In that case we call it on the "same" amount we initially allocated for this path, and which
- // could have been reduced on the way. In that case, there is also a risk of exceeding
- // available_liquidity inside this function, because the function is unaware of this bound.
- // In our specific recomputation cases where we never increase the value the risk is pretty low.
- // This function, however, does not support arbitrarily increasing the value being transferred,
- // and the exception will be triggered.
+ // Sometimes we call this function right after constructing a path which is inconsistent in
+ // that it the value being transferred has decreased while we were doing path finding, leading
+ // to the fees being paid not lining up with the actual limits.
+ //
+ // Note that this function is not aware of the available_liquidity limit, and thus does not
+ // support increasing the value being transferred.
fn update_value_and_recompute_fees(&mut self, value_msat: u64) {
- assert!(value_msat <= self.hops.last().unwrap().route_hop.fee_msat);
+ assert!(value_msat <= self.hops.last().unwrap().0.fee_msat);
let mut total_fee_paid_msat = 0 as u64;
for i in (0..self.hops.len()).rev() {
// htlc_minimum_msat of the current channel. Last hop is handled separately.
let mut cur_hop_fees_msat = 0;
if !last_hop {
- cur_hop_fees_msat = self.hops.get(i + 1).unwrap().hop_use_fee_msat;
+ cur_hop_fees_msat = self.hops.get(i + 1).unwrap().0.hop_use_fee_msat;
}
- let mut cur_hop = self.hops.get_mut(i).unwrap();
+ let mut cur_hop = &mut self.hops.get_mut(i).unwrap().0;
cur_hop.next_hops_fee_msat = total_fee_paid_msat;
// Overpay in fees if we can't save these funds due to htlc_minimum_msat.
// We try to account for htlc_minimum_msat in scoring (add_entry!), so that nodes don't
if last_hop {
// Final hop is a special case: it usually has just value_msat (by design), but also
// it still could overpay for the htlc_minimum_msat.
- cur_hop.route_hop.fee_msat = cur_hop_transferred_amount_msat;
+ cur_hop.fee_msat = cur_hop_transferred_amount_msat;
} else {
// Propagate updated fees for the use of the channels to one hop back, where they
// will be actually paid (fee_msat). The last hop is handled above separately.
- cur_hop.route_hop.fee_msat = cur_hop_fees_msat;
+ cur_hop.fee_msat = cur_hop_fees_msat;
}
// Fee for the use of the current hop which will be deducted on the previous hop.
}
}
+/// Gets a keysend route from us (payer) to the given target node (payee). This is needed because
+/// keysend payments do not have an invoice from which to pull the payee's supported features, which
+/// makes it tricky to otherwise supply the `payee_features` parameter of `get_route`.
+pub fn get_keysend_route<L: Deref>(our_node_id: &PublicKey, network: &NetworkGraph, payee:
+ &PublicKey, first_hops: Option<&[&ChannelDetails]>, last_hops: &[&RouteHint],
+ final_value_msat: u64, final_cltv: u32, logger: L) -> Result<Route,
+ LightningError> where L::Target: Logger {
+ let invoice_features = InvoiceFeatures::for_keysend();
+ get_route(our_node_id, network, payee, Some(invoice_features), first_hops, last_hops,
+ final_value_msat, final_cltv, logger)
+}
+
/// Gets a route from us (payer) to the given target node (payee).
///
/// If the payee provided features in their invoice, they should be provided via payee_features.
/// Without this, MPP will only be used if the payee's features are available in the network graph.
///
-/// Extra routing hops between known nodes and the target will be used if they are included in
-/// last_hops.
+/// Private routing paths between a public node and the target may be included in `last_hops`.
+/// Currently, only the last hop in each path is considered.
///
/// If some channels aren't announced, it may be useful to fill in a first_hops with the
/// results from a local ChannelManager::list_usable_channels() call. If it is filled in, our
return Err(LightningError{err: "Cannot send a payment of 0 msat".to_owned(), action: ErrorAction::IgnoreError});
}
- for last_hop in last_hops {
+ let last_hops = last_hops.iter().filter_map(|hops| hops.0.last()).collect::<Vec<_>>();
+ for last_hop in last_hops.iter() {
if last_hop.src_node_id == *payee {
return Err(LightningError{err: "Last hop cannot have a payee as a source.".to_owned(), action: ErrorAction::IgnoreError});
}
// 8. Choose the best route by the lowest total fee.
// As for the actual search algorithm,
- // we do a payee-to-payer 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 A*").
+ // 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*").
+ //
+ // 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
+ // liquidity limit (via htlc_maximum_msat, on-chain capacity or assumed liquidity limits) then
+ // the value we are currently attempting to send over a path, we simply reduce the value being
+ // sent along the path for any hops after that channel. This may imply that later fees (which
+ // we've already tabulated) are lower because a smaller value is passing through the channels
+ // (and the proportional fee is thus lower). There isn't a trivial way to recalculate the
+ // channels which were selected earlier (and which may still be used for other paths without a
+ // lower liquidity limit), so we simply accept that some liquidity-limited paths may be
+ // de-preferenced.
+ //
+ // One potentially problematic case for this algorithm would be if there are many
+ // liquidity-limited paths which are liquidity-limited near the destination (ie early in our
+ // graph walking), we may never find a path which is not liquidity-limited and has lower
+ // proportional fee (and only lower absolute fee when considering the ultimate value sent).
+ // Because we only consider paths with at least 5% of the total value being sent, the damage
+ // from such a case should be limited, however this could be further reduced in the future by
+ // calculating fees on the amount we wish to route over a path, ie ignoring the liquidity
+ // limits for the purposes of fee calculation.
+ //
+ // Alternatively, we could store more detailed path information in the heap (targets, below)
+ // and index the best-path map (dist, below) by node *and* HTLC limits, however that would blow
+ // up the runtime significantly both algorithmically (as we'd traverse nodes multiple times)
+ // and practically (as we would need to store dynamically-allocated path information in heap
+ // objects, increasing malloc traffic and indirect memory access significantly). Further, the
+ // results of such an algorithm would likely be biased towards lower-value paths.
+ //
+ // Further, we could return to a faithful Dijkstra's algorithm by rejecting paths with limits
+ // outside of our current search value, running a path search more times to gather candidate
+ // paths at different values. While this may be acceptable, further path searches may increase
+ // 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 mut targets = BinaryHeap::new(); //TODO: Do we care about switching to eg Fibbonaci heap?
- let mut dist = HashMap::with_capacity(network.get_nodes().len());
-
- // When arranging a route, we select multiple paths so that we can make a multi-path payment.
- // Don't stop searching for paths when we think they're
- // sufficient to transfer a given value aggregately.
- // Search for higher value, so that we collect many more paths,
- // and then select the best combination among them.
- const ROUTE_CAPACITY_PROVISION_FACTOR: u64 = 3;
- let recommended_value_msat = final_value_msat * ROUTE_CAPACITY_PROVISION_FACTOR as u64;
-
// Allow MPP only if we have a features set from somewhere that indicates the payee supports
// it. If the payee supports it they're supposed to include it in the invoice, so that should
// work reliably.
// Prepare the data we'll use for payee-to-payer search by
// inserting first hops suggested by the caller as targets.
// Our search will then attempt to reach them while traversing from the payee node.
- let mut first_hop_targets = HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
+ let mut first_hop_targets: HashMap<_, (_, ChannelFeatures, _, NodeFeatures)> =
+ 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 {
let short_channel_id = chan.short_channel_id.expect("first_hops should be filled in with usable channels, not pending ones");
- if chan.remote_network_id == *our_node_id {
+ if chan.counterparty.node_id == *our_node_id {
return Err(LightningError{err: "First hop cannot have our_node_id as a destination.".to_owned(), action: ErrorAction::IgnoreError});
}
- first_hop_targets.insert(chan.remote_network_id, (short_channel_id, chan.counterparty_features.clone(), chan.outbound_capacity_msat));
+ first_hop_targets.insert(chan.counterparty.node_id, (short_channel_id, chan.counterparty.features.to_context(), chan.outbound_capacity_msat, chan.counterparty.features.to_context()));
}
if first_hop_targets.is_empty() {
return Err(LightningError{err: "Cannot route when there are no outbound routes away from us".to_owned(), action: ErrorAction::IgnoreError});
}
}
+ let empty_channel_features = ChannelFeatures::empty();
+
+ // The main heap containing all candidate next-hops sorted by their score (max(A* 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::new();
+
+ // Map from node_id to information about the best current path to that node, including feerate
+ // information.
+ let mut dist = HashMap::with_capacity(network.get_nodes().len());
+
+ // During routing, if we ignore a path due to an htlc_minimum_msat limit, we set this,
+ // indicating that we may wish to try again with a higher value, potentially paying to meet an
+ // htlc_minimum with extra fees while still finding a cheaper path.
+ let mut hit_minimum_limit;
+
+ // When arranging a route, we select multiple paths so that we can make a multi-path payment.
+ // We start with a path_value of the exact amount we want, and if that generates a route we may
+ // return it immediately. Otherwise, we don't stop searching for paths until we have 3x the
+ // amount we want in total across paths, selecting the best subset at the end.
+ const ROUTE_CAPACITY_PROVISION_FACTOR: u64 = 3;
+ 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 `outbound_capacity_msat` in `first_hops`).
- let mut bookkeeped_channels_liquidity_available_msat = HashMap::new();
+ let mut bookkeeped_channels_liquidity_available_msat = HashMap::with_capacity(network.get_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);
// - when we want to stop looking for new paths.
let mut already_collected_value_msat = 0;
+ log_trace!(logger, "Building path from {} (payee) to {} (us/payer) for value {} msat.", payee, our_node_id, final_value_msat);
+
macro_rules! add_entry {
// Adds entry which goes from $src_node_id to $dest_node_id
// over the channel with id $chan_id with fees described in
// $directional_info.
// $next_hops_fee_msat represents the fees paid for using all the channel *after* this one,
// since that value has to be transferred over this channel.
+ // Returns whether this channel caused an update to `targets`.
( $chan_id: expr, $src_node_id: expr, $dest_node_id: expr, $directional_info: expr, $capacity_sats: expr, $chan_features: expr, $next_hops_fee_msat: expr,
- $next_hops_value_contribution: expr ) => {
+ $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr ) => { {
+ // We "return" whether we updated the path at the end, via this:
+ let mut did_add_update_path_to_src_node = false;
// Channels to self should not be used. This is more of belt-and-suspenders, because in
// practice these cases should be caught earlier:
// - for regular channels at channel announcement (TODO)
// Can't overflow due to how the values were computed right above.
None => unreachable!(),
};
+ #[allow(unused_comparisons)] // $next_hops_path_htlc_minimum_msat is 0 in some calls so rustc complains
+ let over_path_minimum_msat = amount_to_transfer_over_msat >= $directional_info.htlc_minimum_msat &&
+ amount_to_transfer_over_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.
- // TODO: Explore simply adding fee to hit htlc_minimum_msat
- if contributes_sufficient_value && amount_to_transfer_over_msat >= $directional_info.htlc_minimum_msat {
+ if !over_path_minimum_msat {
+ hit_minimum_limit = true;
+ } else if contributes_sufficient_value {
// Note that low contribution here (limited by available_liquidity_msat)
// might violate htlc_minimum_msat on the hops which are next along the
// payment path (upstream to the payee). To avoid that, we recompute path
// path fees knowing the final path contribution after constructing it.
+ let path_htlc_minimum_msat = match compute_fees($next_hops_path_htlc_minimum_msat, $directional_info.fees)
+ .map(|fee_msat| fee_msat.checked_add($next_hops_path_htlc_minimum_msat)) {
+ Some(Some(value_msat)) => cmp::max(value_msat, $directional_info.htlc_minimum_msat),
+ _ => u64::max_value()
+ };
let hm_entry = dist.entry(&$src_node_id);
let old_entry = hm_entry.or_insert_with(|| {
// If there was previously no known way to access
fee_proportional_millionths = fees.proportional_millionths;
}
PathBuildingHop {
- route_hop: RouteHop {
- pubkey: $dest_node_id.clone(),
- node_features: NodeFeatures::empty(),
- short_channel_id: 0,
- channel_features: $chan_features.clone(),
- fee_msat: 0,
- cltv_expiry_delta: 0,
- },
+ pubkey: $dest_node_id.clone(),
+ short_channel_id: 0,
+ channel_features: $chan_features,
+ fee_msat: 0,
+ cltv_expiry_delta: 0,
src_lowest_inbound_fees: RoutingFees {
base_msat: fee_base_msat,
proportional_millionths: fee_proportional_millionths,
hop_use_fee_msat: u64::max_value(),
total_fee_msat: u64::max_value(),
htlc_minimum_msat: $directional_info.htlc_minimum_msat,
+ path_htlc_minimum_msat,
+ was_processed: false,
+ #[cfg(any(test, feature = "fuzztarget"))]
+ value_contribution_msat,
}
});
- let mut hop_use_fee_msat = 0;
- let mut total_fee_msat = $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, $directional_info.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;
- if let Some(prev_hop_fee_msat) = compute_fees(total_fee_msat + amount_to_transfer_over_msat,
- old_entry.src_lowest_inbound_fees) {
- if let Some(incremented_total_fee_msat) = total_fee_msat.checked_add(prev_hop_fee_msat) {
- total_fee_msat = incremented_total_fee_msat;
- }
- else {
- // max_value means we'll always fail
- // the old_entry.total_fee_msat > total_fee_msat check
- total_fee_msat = u64::max_value();
- }
- } else {
- // max_value means we'll always fail
- // the old_entry.total_fee_msat > total_fee_msat check
- total_fee_msat = u64::max_value();
+ #[allow(unused_mut)] // We only use the mut in cfg(test)
+ let mut should_process = !old_entry.was_processed;
+ #[cfg(any(test, feature = "fuzztarget"))]
+ {
+ // In test/fuzzing builds, we do extra checks to make sure the skipping
+ // of already-seen nodes only happens in cases we expect (see below).
+ if !should_process { should_process = true; }
+ }
+
+ if should_process {
+ let mut hop_use_fee_msat = 0;
+ let mut total_fee_msat = $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, $directional_info.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();
+ }
+ };
}
}
}
- }
-
- let new_graph_node = RouteGraphNode {
- pubkey: $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,
- value_contribution_msat: value_contribution_msat,
- };
-
- // Update the way of reaching $src_node_id with the given $chan_id (from $dest_node_id),
- // if this way is cheaper than the already known
- // (considering the cost to "reach" this channel from the route destination,
- // the cost of using this channel,
- // and the cost of routing to the source node of this channel).
- // Also, consider that htlc_minimum_msat_difference, because we might end up
- // paying it. Consider the following exploit:
- // we use 2 paths to transfer 1.5 BTC. One of them is 0-fee normal 1 BTC path,
- // and for the other one we picked a 1sat-fee path with htlc_minimum_msat of
- // 1 BTC. Now, since the latter is more expensive, we gonna try to cut it
- // by 0.5 BTC, but then match htlc_minimum_msat by paying a fee of 0.5 BTC
- // to this channel.
- // TODO: this scoring could be smarter (e.g. 0.5*htlc_minimum_msat here).
- let mut old_cost = old_entry.total_fee_msat;
- if let Some(increased_old_cost) = old_cost.checked_add(old_entry.htlc_minimum_msat) {
- old_cost = increased_old_cost;
- } else {
- old_cost = u64::max_value();
- }
-
- let mut new_cost = total_fee_msat;
- if let Some(increased_new_cost) = new_cost.checked_add($directional_info.htlc_minimum_msat) {
- new_cost = increased_new_cost;
- } else {
- new_cost = u64::max_value();
- }
- if new_cost < old_cost {
- targets.push(new_graph_node);
- old_entry.next_hops_fee_msat = $next_hops_fee_msat;
- old_entry.hop_use_fee_msat = hop_use_fee_msat;
- old_entry.total_fee_msat = total_fee_msat;
- old_entry.route_hop = RouteHop {
- pubkey: $dest_node_id.clone(),
- node_features: NodeFeatures::empty(),
- short_channel_id: $chan_id.clone(),
- channel_features: $chan_features.clone(),
- fee_msat: 0, // This value will be later filled with hop_use_fee_msat of the following channel
- cltv_expiry_delta: $directional_info.cltv_expiry_delta as u32,
+ let new_graph_node = RouteGraphNode {
+ pubkey: $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,
+ value_contribution_msat: value_contribution_msat,
+ path_htlc_minimum_msat,
};
- old_entry.channel_fees = $directional_info.fees;
- // It's probably fine to replace the old entry, because the new one
- // passed the htlc_minimum-related checks above.
- old_entry.htlc_minimum_msat = $directional_info.htlc_minimum_msat;
+
+ // Update the way of reaching $src_node_id with the given $chan_id (from $dest_node_id),
+ // if this way is cheaper than the already known
+ // (considering the cost to "reach" this channel from the route destination,
+ // the cost of using this channel,
+ // and the cost of routing to the source node of this channel).
+ // Also, consider that htlc_minimum_msat_difference, because we might end up
+ // paying it. Consider the following exploit:
+ // we use 2 paths to transfer 1.5 BTC. One of them is 0-fee normal 1 BTC path,
+ // and for the other one we picked a 1sat-fee path with htlc_minimum_msat of
+ // 1 BTC. Now, since the latter is more expensive, we gonna try to cut it
+ // by 0.5 BTC, but then match htlc_minimum_msat by paying a fee of 0.5 BTC
+ // to this channel.
+ // Ideally the scoring could be smarter (e.g. 0.5*htlc_minimum_msat here),
+ // but it may require additional tracking - we don't want to double-count
+ // 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);
+ let new_cost = cmp::max(total_fee_msat, path_htlc_minimum_msat);
+
+ if !old_entry.was_processed && new_cost < old_cost {
+ targets.push(new_graph_node);
+ old_entry.next_hops_fee_msat = $next_hops_fee_msat;
+ old_entry.hop_use_fee_msat = hop_use_fee_msat;
+ old_entry.total_fee_msat = total_fee_msat;
+ old_entry.pubkey = $dest_node_id.clone();
+ old_entry.short_channel_id = $chan_id.clone();
+ old_entry.channel_features = $chan_features;
+ 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 = $directional_info.cltv_expiry_delta as u32;
+ old_entry.channel_fees = $directional_info.fees;
+ old_entry.htlc_minimum_msat = $directional_info.htlc_minimum_msat;
+ old_entry.path_htlc_minimum_msat = path_htlc_minimum_msat;
+ #[cfg(any(test, feature = "fuzztarget"))]
+ {
+ old_entry.value_contribution_msat = value_contribution_msat;
+ }
+ did_add_update_path_to_src_node = true;
+ } else if old_entry.was_processed && new_cost < old_cost {
+ #[cfg(any(test, feature = "fuzztarget"))]
+ {
+ // If we're skipping processing a node which was previously
+ // processed even though we found another path to it with a
+ // cheaper fee, check that it was because the second path we
+ // found (which we are processing now) has a lower value
+ // contribution due to an HTLC minimum limit.
+ //
+ // e.g. take a graph with two paths from node 1 to node 2, one
+ // through channel A, and one through channel B. Channel A and
+ // B are both in the to-process heap, with their scores set by
+ // a higher htlc_minimum than fee.
+ // Channel A is processed first, and the channels onwards from
+ // node 1 are added to the to-process heap. Thereafter, we pop
+ // Channel B off of the heap, note that it has a much more
+ // restrictive htlc_maximum_msat, and recalculate the fees for
+ // all of node 1's channels using the new, reduced, amount.
+ //
+ // This would be bogus - we'd be selecting a higher-fee path
+ // with a lower htlc_maximum_msat instead of the one we'd
+ // already decided to use.
+ debug_assert!(path_htlc_minimum_msat < old_entry.path_htlc_minimum_msat);
+ debug_assert!(value_contribution_msat < old_entry.value_contribution_msat);
+ }
+ }
}
}
}
}
- };
+ did_add_update_path_to_src_node
+ } }
}
+ let empty_node_features = NodeFeatures::empty();
// 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,
// meaning how much will be paid in fees after this node (to the best of our knowledge).
// This data can later be helpful to optimize routing (pay lower fees).
macro_rules! add_entries_to_cheapest_to_target_node {
- ( $node: expr, $node_id: expr, $fee_to_target_msat: expr, $next_hops_value_contribution: expr ) => {
- if first_hops.is_some() {
- if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat)) = first_hop_targets.get(&$node_id) {
- add_entry!(first_hop, *our_node_id, $node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features.to_context(), $fee_to_target_msat, $next_hops_value_contribution);
+ ( $node: expr, $node_id: expr, $fee_to_target_msat: expr, $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr ) => {
+ let skip_node = if let Some(elem) = dist.get_mut($node_id) {
+ let was_processed = elem.was_processed;
+ elem.was_processed = true;
+ was_processed
+ } else {
+ // Entries are added to dist in add_entry!() when there is a channel from a node.
+ // Because there are no channels from payee, it will not have a dist entry at this point.
+ // If we're processing any other node, it is always be the result of a channel from it.
+ assert_eq!($node_id, payee);
+ false
+ };
+
+ if !skip_node {
+ if first_hops.is_some() {
+ if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat, _)) = first_hop_targets.get(&$node_id) {
+ add_entry!(first_hop, *our_node_id, $node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat);
+ }
}
- }
- let features;
- if let Some(node_info) = $node.announcement_info.as_ref() {
- features = node_info.features.clone();
- } else {
- features = NodeFeatures::empty();
- }
+ let features = if let Some(node_info) = $node.announcement_info.as_ref() {
+ &node_info.features
+ } else {
+ &empty_node_features
+ };
- if !features.requires_unknown_bits() {
- for chan_id in $node.channels.iter() {
- let chan = network.get_channels().get(chan_id).unwrap();
- if !chan.features.requires_unknown_bits() {
- if chan.node_one == *$node_id {
- // ie $node is one, ie next hop in A* is two, via the two_to_one channel
- if first_hops.is_none() || chan.node_two != *our_node_id {
- if let Some(two_to_one) = chan.two_to_one.as_ref() {
- if two_to_one.enabled {
- add_entry!(chan_id, chan.node_two, chan.node_one, two_to_one, chan.capacity_sats, chan.features, $fee_to_target_msat, $next_hops_value_contribution);
+ if !features.requires_unknown_bits() {
+ for chan_id in $node.channels.iter() {
+ let chan = network.get_channels().get(chan_id).unwrap();
+ if !chan.features.requires_unknown_bits() {
+ if chan.node_one == *$node_id {
+ // ie $node is one, ie next hop in A* is two, via the two_to_one channel
+ if first_hops.is_none() || chan.node_two != *our_node_id {
+ if let Some(two_to_one) = chan.two_to_one.as_ref() {
+ if two_to_one.enabled {
+ add_entry!(chan_id, chan.node_two, chan.node_one, two_to_one, chan.capacity_sats, &chan.features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat);
+ }
}
}
- }
- } else {
- if first_hops.is_none() || chan.node_one != *our_node_id {
- if let Some(one_to_two) = chan.one_to_two.as_ref() {
- if one_to_two.enabled {
- add_entry!(chan_id, chan.node_one, chan.node_two, one_to_two, chan.capacity_sats, chan.features, $fee_to_target_msat, $next_hops_value_contribution);
+ } else {
+ if first_hops.is_none() || chan.node_one != *our_node_id {
+ if let Some(one_to_two) = chan.one_to_two.as_ref() {
+ if one_to_two.enabled {
+ add_entry!(chan_id, chan.node_one, chan.node_two, one_to_two, chan.capacity_sats, &chan.features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat);
+ }
}
}
-
}
}
}
// the further iterations of path finding. Also don't erase first_hop_targets.
targets.clear();
dist.clear();
+ hit_minimum_limit = false;
// If first hop is a private channel and the only way to reach the payee, this is the only
// place where it could be added.
if first_hops.is_some() {
- if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat)) = first_hop_targets.get(&payee) {
- add_entry!(first_hop, *our_node_id, payee, dummy_directional_info, Some(outbound_capacity_msat / 1000), features.to_context(), 0, recommended_value_msat);
+ if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat, _)) = first_hop_targets.get(&payee) {
+ add_entry!(first_hop, *our_node_id, payee, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, 0, path_value_msat, 0);
}
}
// If not, targets.pop() will not even let us enter the loop in step 2.
None => {},
Some(node) => {
- add_entries_to_cheapest_to_target_node!(node, payee, 0, recommended_value_msat);
+ add_entries_to_cheapest_to_target_node!(node, payee, 0, path_value_msat, 0);
},
}
// it matters only if the fees are exactly the same.
for hop in last_hops.iter() {
let have_hop_src_in_graph =
- if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat)) = first_hop_targets.get(&hop.src_node_id) {
- // If this hop connects to a node with which we have a direct channel, ignore
- // the network graph and add both the hop and our direct channel to
- // the candidate set.
- //
- // Currently there are no channel-context features defined, so we are a
- // bit lazy here. In the future, we should pull them out via our
- // ChannelManager, but there's no reason to waste the space until we
- // need them.
- add_entry!(first_hop, *our_node_id , hop.src_node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features.to_context(), 0, recommended_value_msat);
- true
- } else {
- // In any other case, only add the hop if the source is in the regular network
- // graph:
- network.get_nodes().get(&hop.src_node_id).is_some()
- };
+ // Only add the last hop to our candidate set if either we have a direct channel or
+ // they are in the regular network graph.
+ first_hop_targets.get(&hop.src_node_id).is_some() ||
+ network.get_nodes().get(&hop.src_node_id).is_some();
if have_hop_src_in_graph {
// BOLT 11 doesn't allow inclusion of features for the last hop hints, which
// really sucks, cause we're gonna need that eventually.
htlc_maximum_msat: hop.htlc_maximum_msat,
fees: hop.fees,
};
- add_entry!(hop.short_channel_id, hop.src_node_id, payee, directional_info, None::<u64>, ChannelFeatures::empty(), 0, recommended_value_msat);
+ // We assume that the recipient only included route hints for routes which had
+ // sufficient value to route `final_value_msat`. Note that in the case of "0-value"
+ // invoices where the invoice does not specify value this may not be the case, but
+ // better to include the hints than not.
+ if add_entry!(hop.short_channel_id, hop.src_node_id, payee, directional_info, Some((final_value_msat + 999) / 1000), &empty_channel_features, 0, path_value_msat, 0) {
+ // If this hop connects to a node with which we have a direct channel,
+ // ignore the network graph and, if the last hop was added, add our
+ // direct channel to the candidate set.
+ //
+ // Note that we *must* check if the last hop was added as `add_entry`
+ // always assumes that the third argument is a node to which we have a
+ // path.
+ if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat, _)) = first_hop_targets.get(&hop.src_node_id) {
+ add_entry!(first_hop, *our_node_id , hop.src_node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, 0, path_value_msat, 0);
+ }
+ }
}
}
+ log_trace!(logger, "Starting main path collection loop with {} nodes pre-filled from first/last hops.", targets.len());
+
// At this point, targets are filled with the data from first and
// last hops communicated by the caller, and the payment receiver.
let mut found_new_path = false;
// Both these cases (and other cases except reaching recommended_value_msat) mean that
// paths_collection will be stopped because found_new_path==false.
// This is not necessarily a routing failure.
- 'path_construction: while let Some(RouteGraphNode { pubkey, lowest_fee_to_node, value_contribution_msat, .. }) = targets.pop() {
+ 'path_construction: while let Some(RouteGraphNode { pubkey, lowest_fee_to_node, value_contribution_msat, path_htlc_minimum_msat, .. }) = targets.pop() {
// Since we're going payee-to-payer, hitting our node as a target means we should stop
// traversing the graph and arrange the path out of what we found.
if pubkey == *our_node_id {
let mut new_entry = dist.remove(&our_node_id).unwrap();
- let mut ordered_hops = vec!(new_entry.clone());
+ let mut ordered_hops = vec!((new_entry.clone(), NodeFeatures::empty()));
'path_walk: loop {
- if let Some(&(_, ref features, _)) = first_hop_targets.get(&ordered_hops.last().unwrap().route_hop.pubkey) {
- ordered_hops.last_mut().unwrap().route_hop.node_features = features.to_context();
- } else if let Some(node) = network.get_nodes().get(&ordered_hops.last().unwrap().route_hop.pubkey) {
+ if let Some(&(_, _, _, ref features)) = first_hop_targets.get(&ordered_hops.last().unwrap().0.pubkey) {
+ ordered_hops.last_mut().unwrap().1 = features.clone();
+ } else if let Some(node) = network.get_nodes().get(&ordered_hops.last().unwrap().0.pubkey) {
if let Some(node_info) = node.announcement_info.as_ref() {
- ordered_hops.last_mut().unwrap().route_hop.node_features = node_info.features.clone();
+ ordered_hops.last_mut().unwrap().1 = node_info.features.clone();
} else {
- ordered_hops.last_mut().unwrap().route_hop.node_features = NodeFeatures::empty();
+ ordered_hops.last_mut().unwrap().1 = NodeFeatures::empty();
}
} else {
// We should be able to fill in features for everything except the last
// hop, if the last hop was provided via a BOLT 11 invoice (though we
// should be able to extend it further as BOLT 11 does have feature
// flags for the last hop node itself).
- assert!(ordered_hops.last().unwrap().route_hop.pubkey == *payee);
+ assert!(ordered_hops.last().unwrap().0.pubkey == *payee);
}
// Means we succesfully traversed from the payer to the payee, now
// save this path for the payment route. Also, update the liquidity
// remaining on the used hops, so that we take them into account
// while looking for more paths.
- if ordered_hops.last().unwrap().route_hop.pubkey == *payee {
+ if ordered_hops.last().unwrap().0.pubkey == *payee {
break 'path_walk;
}
- new_entry = match dist.remove(&ordered_hops.last().unwrap().route_hop.pubkey) {
+ new_entry = match dist.remove(&ordered_hops.last().unwrap().0.pubkey) {
Some(payment_hop) => payment_hop,
// We can't arrive at None because, if we ever add an entry to targets,
// we also fill in the entry in dist (see add_entry!).
// We "propagate" the fees one hop backward (topologically) here,
// 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().route_hop.fee_msat = new_entry.hop_use_fee_msat;
- ordered_hops.last_mut().unwrap().route_hop.cltv_expiry_delta = new_entry.route_hop.cltv_expiry_delta;
- ordered_hops.push(new_entry.clone());
+ 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().route_hop.fee_msat = value_contribution_msat;
- ordered_hops.last_mut().unwrap().hop_use_fee_msat = 0;
- ordered_hops.last_mut().unwrap().route_hop.cltv_expiry_delta = final_cltv;
+ 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;
+
+ 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);
let mut payment_path = PaymentPath {hops: ordered_hops};
// on some channels we already passed (assuming dest->source direction). Here, we
// recompute the fees again, so that if that's the case, we match the currently
// underpaid htlc_minimum_msat with fees.
- payment_path.update_value_and_recompute_fees(value_contribution_msat);
+ payment_path.update_value_and_recompute_fees(cmp::min(value_contribution_msat, final_value_msat));
// Since a path allows to transfer as much value as
// the smallest channel it has ("bottleneck"), we should recompute
// might have been computed considering a larger value.
// Remember that we used these channels so that we don't rely
// on the same liquidity in future paths.
- for payment_hop in payment_path.hops.iter() {
- let channel_liquidity_available_msat = bookkeeped_channels_liquidity_available_msat.get_mut(&payment_hop.route_hop.short_channel_id).unwrap();
+ 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 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 *channel_liquidity_available_msat < spent_on_hop_msat {
- // This should not happen because we do recompute fees right before,
- // trying to avoid cases when a hop is not usable due to the fee situation.
- break 'path_construction;
+ if spent_on_hop_msat == *channel_liquidity_available_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;
}
+ 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() - 1) / 2].0.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;
+ }
+
// Track the total amount all our collected paths allow to send so that we:
// - know when to stop looking for more paths
// - know which of the hops are useless considering how much more sats we need
break 'path_construction;
}
+ // If we found a path back to the payee, we shouldn't try to process it again. This is
+ // the equivalent of the `elem.was_processed` check in
+ // add_entries_to_cheapest_to_target_node!() (see comment there for more info).
+ if pubkey == *payee { continue 'path_construction; }
+
// Otherwise, since the current target node is not us,
// keep "unrolling" the payment graph from payee to payer by
// finding a way to reach the current target from the payer side.
match network.get_nodes().get(&pubkey) {
None => {},
Some(node) => {
- add_entries_to_cheapest_to_target_node!(node, &pubkey, lowest_fee_to_node, value_contribution_msat);
+ add_entries_to_cheapest_to_target_node!(node, &pubkey, lowest_fee_to_node, value_contribution_msat, path_htlc_minimum_msat);
},
}
}
}
// Step (3).
- // Stop either when recommended value is reached,
- // or if during last iteration no new path was found.
- // In the latter case, making another path finding attempt could not help,
- // because we deterministically terminate the search due to low liquidity.
+ // Stop either when the recommended value is reached or if no new path was found in this
+ // iteration.
+ // In the latter case, making another path finding attempt won't help,
+ // because we deterministically terminated the search due to low liquidity.
if already_collected_value_msat >= recommended_value_msat || !found_new_path {
+ log_trace!(logger, "Have now collected {} msat (seeking {} msat) in paths. Last path loop {} a new path.",
+ already_collected_value_msat, recommended_value_msat, if found_new_path { "found" } else { "did not find" });
break 'paths_collection;
+ } else if found_new_path && already_collected_value_msat == final_value_msat && payment_paths.len() == 1 {
+ // Further, if this was our first walk of the graph, and we weren't limited by an
+ // htlc_minimum_msat, return immediately because this path should suffice. If we were
+ // limited by an htlc_minimum_msat value, find another path with a higher value,
+ // potentially allowing us to pay fees to meet the htlc_minimum on the new path while
+ // still keeping a lower total fee than this path.
+ if !hit_minimum_limit {
+ log_trace!(logger, "Collected exactly our payment amount on the first pass, without hitting an htlc_minimum_msat limit, exiting.");
+ break 'paths_collection;
+ }
+ log_trace!(logger, "Collected our payment amount on the first pass, but running again to collect extra paths with a potentially higher limit.");
+ path_value_msat = recommended_value_msat;
}
}
// 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.channel_fees.proportional_millionths as u64).sum::<u64>() });
+ cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.0.channel_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<RouteHop>>::new();
for payment_path in drawn_routes.first().unwrap() {
- selected_paths.push(payment_path.hops.iter().map(|payment_hop| payment_hop.route_hop.clone()).collect());
+ selected_paths.push(payment_path.hops.iter().map(|(payment_hop, node_features)| {
+ RouteHop {
+ pubkey: payment_hop.pubkey,
+ node_features: node_features.clone(),
+ short_channel_id: payment_hop.short_channel_id,
+ channel_features: payment_hop.channel_features.clone(),
+ fee_msat: payment_hop.fee_msat,
+ cltv_expiry_delta: payment_hop.cltv_expiry_delta,
+ }
+ }).collect());
}
if let Some(features) = &payee_features {
}
let route = Route { paths: selected_paths };
- log_trace!(logger, "Got route: {}", log_route!(route));
+ log_info!(logger, "Got route to {}: {}", payee, log_route!(route));
Ok(route)
}
#[cfg(test)]
mod tests {
- use routing::router::{get_route, RouteHint, RoutingFees};
+ use routing::router::{get_route, Route, RouteHint, RouteHintHop, RoutingFees};
use routing::network_graph::{NetworkGraph, NetGraphMsgHandler};
+ use chain::transaction::OutPoint;
use ln::features::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
use ln::msgs::{ErrorAction, LightningError, OptionalField, UnsignedChannelAnnouncement, ChannelAnnouncement, RoutingMessageHandler,
NodeAnnouncement, UnsignedNodeAnnouncement, ChannelUpdate, UnsignedChannelUpdate};
use bitcoin::secp256k1::key::{PublicKey,SecretKey};
use bitcoin::secp256k1::{Secp256k1, All};
- use std::sync::Arc;
+ use prelude::*;
+ use sync::{self, Arc};
+
+ fn get_channel_details(short_channel_id: Option<u64>, node_id: PublicKey,
+ features: InitFeatures, outbound_capacity_msat: u64) -> channelmanager::ChannelDetails {
+ channelmanager::ChannelDetails {
+ channel_id: [0; 32],
+ counterparty: channelmanager::ChannelCounterparty {
+ features,
+ node_id,
+ unspendable_punishment_reserve: 0,
+ forwarding_info: None,
+ },
+ funding_txo: Some(OutPoint { txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0 }),
+ short_channel_id,
+ channel_value_satoshis: 0,
+ user_id: 0,
+ outbound_capacity_msat,
+ inbound_capacity_msat: 42,
+ unspendable_punishment_reserve: None,
+ confirmations_required: None,
+ force_close_spend_delay: None,
+ is_outbound: true, is_funding_locked: true,
+ is_usable: true, is_public: true,
+ }
+ }
// Using the same keys for LN and BTC ids
fn add_channel(net_graph_msg_handler: &NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>, secp_ctx: &Secp256k1<All>, node_1_privkey: &SecretKey,
}
}
- fn build_graph() -> (Secp256k1<All>, NetGraphMsgHandler<std::sync::Arc<test_utils::TestChainSource>, std::sync::Arc<crate::util::test_utils::TestLogger>>, std::sync::Arc<test_utils::TestChainSource>, std::sync::Arc<test_utils::TestLogger>) {
+ fn build_graph() -> (Secp256k1<All>, NetGraphMsgHandler<sync::Arc<test_utils::TestChainSource>, sync::Arc<crate::util::test_utils::TestLogger>>, sync::Arc<test_utils::TestChainSource>, sync::Arc<test_utils::TestLogger>) {
let secp_ctx = Secp256k1::new();
let logger = Arc::new(test_utils::TestLogger::new());
let chain_monitor = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
// Simple route to 2 via 1
- let our_chans = vec![channelmanager::ChannelDetails {
- channel_id: [0; 32],
- short_channel_id: Some(2),
- remote_network_id: our_id,
- counterparty_features: InitFeatures::from_le_bytes(vec![0b11]),
- channel_value_satoshis: 100000,
- user_id: 0,
- outbound_capacity_msat: 100000,
- inbound_capacity_msat: 100000,
- is_live: true,
- }];
+ let our_chans = vec![get_channel_details(Some(2), our_id, InitFeatures::from_le_bytes(vec![0b11]), 100000)];
if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 100, 42, Arc::clone(&logger)) {
assert_eq!(err, "First hop cannot have our_node_id as a destination.");
} else { panic!(); }
// If we specify a channel to node7, that overrides our local channel view and that gets used
- let our_chans = vec![channelmanager::ChannelDetails {
- channel_id: [0; 32],
- short_channel_id: Some(42),
- remote_network_id: nodes[7].clone(),
- counterparty_features: InitFeatures::from_le_bytes(vec![0b11]),
- channel_value_satoshis: 0,
- user_id: 0,
- outbound_capacity_msat: 250_000_000,
- inbound_capacity_msat: 0,
- is_live: true,
- }];
+ let our_chans = vec![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap();
assert_eq!(route.paths[0].len(), 2);
let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
// Disable nodes 1, 2, and 8 by requiring unknown feature bits
- let mut unknown_features = NodeFeatures::known();
- unknown_features.set_required_unknown_bits();
+ let unknown_features = NodeFeatures::known().set_unknown_feature_required();
add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[0], unknown_features.clone(), 1);
add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], unknown_features.clone(), 1);
add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[7], unknown_features.clone(), 1);
} else { panic!(); }
// If we specify a channel to node7, that overrides our local channel view and that gets used
- let our_chans = vec![channelmanager::ChannelDetails {
- channel_id: [0; 32],
- short_channel_id: Some(42),
- remote_network_id: nodes[7].clone(),
- counterparty_features: InitFeatures::from_le_bytes(vec![0b11]),
- channel_value_satoshis: 0,
- user_id: 0,
- outbound_capacity_msat: 250_000_000,
- inbound_capacity_msat: 0,
- is_live: true,
- }];
+ let our_chans = vec![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap();
assert_eq!(route.paths[0].len(), 2);
assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(3));
// If we specify a channel to node7, that overrides our local channel view and that gets used
- let our_chans = vec![channelmanager::ChannelDetails {
- channel_id: [0; 32],
- short_channel_id: Some(42),
- remote_network_id: nodes[7].clone(),
- counterparty_features: InitFeatures::from_le_bytes(vec![0b11]),
- channel_value_satoshis: 0,
- user_id: 0,
- outbound_capacity_msat: 250_000_000,
- inbound_capacity_msat: 0,
- is_live: true,
- }];
+ let our_chans = vec![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap();
assert_eq!(route.paths[0].len(), 2);
base_msat: 0,
proportional_millionths: 0,
};
- vec!(RouteHint {
+ vec![RouteHint(vec![RouteHintHop {
src_node_id: nodes[3].clone(),
short_channel_id: 8,
fees: zero_fees,
cltv_expiry_delta: (8 << 8) | 1,
htlc_minimum_msat: None,
htlc_maximum_msat: None,
- }, RouteHint {
+ }]), RouteHint(vec![RouteHintHop {
src_node_id: nodes[4].clone(),
short_channel_id: 9,
fees: RoutingFees {
cltv_expiry_delta: (9 << 8) | 1,
htlc_minimum_msat: None,
htlc_maximum_msat: None,
- }, RouteHint {
+ }]), RouteHint(vec![RouteHintHop {
src_node_id: nodes[5].clone(),
short_channel_id: 10,
fees: zero_fees,
cltv_expiry_delta: (10 << 8) | 1,
htlc_minimum_msat: None,
htlc_maximum_msat: None,
- })
+ }])]
}
#[test]
// Simple test across 2, 3, 5, and 4 via a last_hop channel
- // First check that lst hop can't have its source as the payee.
- let invalid_last_hop = RouteHint {
+ // First check that last hop can't have its source as the payee.
+ let invalid_last_hop = RouteHint(vec![RouteHintHop {
src_node_id: nodes[6],
short_channel_id: 8,
fees: RoutingFees {
cltv_expiry_delta: (8 << 8) | 1,
htlc_minimum_msat: None,
htlc_maximum_msat: None,
- };
+ }]);
let mut invalid_last_hops = last_hops(&nodes);
invalid_last_hops.push(invalid_last_hop);
let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
// Simple test with outbound channel to 4 to test that last_hops and first_hops connect
- let our_chans = vec![channelmanager::ChannelDetails {
- channel_id: [0; 32],
- short_channel_id: Some(42),
- remote_network_id: nodes[3].clone(),
- counterparty_features: InitFeatures::from_le_bytes(vec![0b11]),
- channel_value_satoshis: 0,
- user_id: 0,
- outbound_capacity_msat: 250_000_000,
- inbound_capacity_msat: 0,
- is_live: true,
- }];
+ let our_chans = vec![get_channel_details(Some(42), nodes[3].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
let mut last_hops = last_hops(&nodes);
let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, Some(&our_chans.iter().collect::<Vec<_>>()), &last_hops.iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger)).unwrap();
assert_eq!(route.paths[0].len(), 2);
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].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
- last_hops[0].fees.base_msat = 1000;
+ last_hops[0].0[0].fees.base_msat = 1000;
// Revert to via 6 as the fee on 8 goes up
let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, None, &last_hops.iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger)).unwrap();
assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
}
- #[test]
- fn unannounced_path_test() {
- // We should be able to send a payment to a destination without any help of a routing graph
- // if we have a channel with a common counterparty that appears in the first and last hop
- // hints.
+ fn do_unannounced_path_test(last_hop_htlc_max: Option<u64>, last_hop_fee_prop: u32, outbound_capacity_msat: u64, route_val: u64) -> Result<Route, LightningError> {
let source_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 41).repeat(32)).unwrap()[..]).unwrap());
let middle_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 42).repeat(32)).unwrap()[..]).unwrap());
let target_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 43).repeat(32)).unwrap()[..]).unwrap());
// If we specify a channel to a middle hop, that overrides our local channel view and that gets used
- let last_hops = vec![RouteHint {
+ let last_hops = RouteHint(vec![RouteHintHop {
src_node_id: middle_node_id,
short_channel_id: 8,
fees: RoutingFees {
base_msat: 1000,
- proportional_millionths: 0,
+ proportional_millionths: last_hop_fee_prop,
},
cltv_expiry_delta: (8 << 8) | 1,
htlc_minimum_msat: None,
- htlc_maximum_msat: None,
- }];
- let our_chans = vec![channelmanager::ChannelDetails {
- channel_id: [0; 32],
- short_channel_id: Some(42),
- remote_network_id: middle_node_id,
- counterparty_features: InitFeatures::from_le_bytes(vec![0b11]),
- channel_value_satoshis: 100000,
- user_id: 0,
- outbound_capacity_msat: 100000,
- inbound_capacity_msat: 100000,
- is_live: true,
- }];
- let route = get_route(&source_node_id, &NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()), &target_node_id, None, Some(&our_chans.iter().collect::<Vec<_>>()), &last_hops.iter().collect::<Vec<_>>(), 100, 42, Arc::new(test_utils::TestLogger::new())).unwrap();
+ htlc_maximum_msat: last_hop_htlc_max,
+ }]);
+ let our_chans = vec![get_channel_details(Some(42), middle_node_id, InitFeatures::from_le_bytes(vec![0b11]), outbound_capacity_msat)];
+ get_route(&source_node_id, &NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()), &target_node_id, None, Some(&our_chans.iter().collect::<Vec<_>>()), &vec![&last_hops], route_val, 42, Arc::new(test_utils::TestLogger::new()))
+ }
+
+ #[test]
+ fn unannounced_path_test() {
+ // We should be able to send a payment to a destination without any help of a routing graph
+ // if we have a channel with a common counterparty that appears in the first and last hop
+ // hints.
+ let route = do_unannounced_path_test(None, 1, 2000000, 1000000).unwrap();
+ let middle_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 42).repeat(32)).unwrap()[..]).unwrap());
+ let target_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 43).repeat(32)).unwrap()[..]).unwrap());
assert_eq!(route.paths[0].len(), 2);
assert_eq!(route.paths[0][0].pubkey, middle_node_id);
assert_eq!(route.paths[0][0].short_channel_id, 42);
- assert_eq!(route.paths[0][0].fee_msat, 1000);
+ assert_eq!(route.paths[0][0].fee_msat, 1001);
assert_eq!(route.paths[0][0].cltv_expiry_delta, (8 << 8) | 1);
assert_eq!(route.paths[0][0].node_features.le_flags(), &[0b11]);
assert_eq!(route.paths[0][0].channel_features.le_flags(), &[0; 0]); // We can't learn any flags from invoices, sadly
assert_eq!(route.paths[0][1].pubkey, target_node_id);
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].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].channel_features.le_flags(), &[0; 0]); // We can't learn any flags from invoices, sadly
}
+ #[test]
+ fn overflow_unannounced_path_test_liquidity_underflow() {
+ // Previously, when we had a last-hop hint connected directly to a first-hop channel, where
+ // the last-hop had a fee which overflowed a u64, we'd panic.
+ // This was due to us adding the first-hop from us unconditionally, causing us to think
+ // we'd built a path (as our node is in the "best candidate" set), when we had not.
+ // In this test, we previously hit a subtraction underflow due to having less available
+ // liquidity at the last hop than 0.
+ assert!(do_unannounced_path_test(Some(21_000_000_0000_0000_000), 0, 21_000_000_0000_0000_000, 21_000_000_0000_0000_000).is_err());
+ }
+
+ #[test]
+ fn overflow_unannounced_path_test_feerate_overflow() {
+ // This tests for the same case as above, except instead of hitting a subtraction
+ // underflow, we hit a case where the fee charged at a hop overflowed.
+ assert!(do_unannounced_path_test(Some(21_000_000_0000_0000_000), 50000, 21_000_000_0000_0000_000, 21_000_000_0000_0000_000).is_err());
+ }
+
#[test]
fn available_amount_while_routing_test() {
// Tests whether we choose the correct available channel amount while routing.
});
// Now, limit the first_hop by the outbound_capacity_msat of 200_000 sats.
- let our_chans = vec![channelmanager::ChannelDetails {
- channel_id: [0; 32],
- short_channel_id: Some(42),
- remote_network_id: nodes[0].clone(),
- counterparty_features: InitFeatures::from_le_bytes(vec![0b11]),
- channel_value_satoshis: 0,
- user_id: 0,
- outbound_capacity_msat: 200_000_000,
- inbound_capacity_msat: 0,
- is_live: true,
- }];
+ let our_chans = vec![get_channel_details(Some(42), nodes[0].clone(), InitFeatures::from_le_bytes(vec![0b11]), 200_000_000)];
{
// Attempt to route more than available results in a failure.
assert_eq!(total_amount_paid_msat, 90_000);
}
}
+
+ #[test]
+ fn min_criteria_consistency() {
+ // Test that we don't use an inconsistent metric between updating and walking nodes during
+ // our Dijkstra's pass. In the initial version of MPP, the "best source" for a given node
+ // was updated with a different criterion from the heap sorting, resulting in loops in
+ // calculated paths. We test for that specific case here.
+
+ // We construct a network that looks like this:
+ //
+ // node2 -1(3)2- node3
+ // 2 2
+ // (2) (4)
+ // 1 1
+ // node1 -1(5)2- node4 -1(1)2- node6
+ // 2
+ // (6)
+ // 1
+ // our_node
+ //
+ // We create a loop on the side of our real path - our destination is node 6, with a
+ // previous hop of node 4. From 4, the cheapest previous path is channel 2 from node 2,
+ // followed by node 3 over channel 3. Thereafter, the cheapest next-hop is back to node 4
+ // (this time over channel 4). Channel 4 has 0 htlc_minimum_msat whereas channel 1 (the
+ // other channel with a previous-hop of node 4) has a high (but irrelevant to the overall
+ // payment) htlc_minimum_msat. In the original algorithm, this resulted in node4's
+ // "previous hop" being set to node 3, creating a loop in the path.
+ let secp_ctx = Secp256k1::new();
+ let logger = Arc::new(test_utils::TestLogger::new());
+ let net_graph_msg_handler = NetGraphMsgHandler::new(genesis_block(Network::Testnet).header.block_hash(), None, Arc::clone(&logger));
+ let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
+
+ add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6);
+ update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 6,
+ timestamp: 1,
+ flags: 0,
+ cltv_expiry_delta: (6 << 8) | 0,
+ htlc_minimum_msat: 0,
+ htlc_maximum_msat: OptionalField::Absent,
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+ add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
+
+ add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
+ update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 5,
+ timestamp: 1,
+ flags: 0,
+ cltv_expiry_delta: (5 << 8) | 0,
+ htlc_minimum_msat: 0,
+ htlc_maximum_msat: OptionalField::Absent,
+ fee_base_msat: 100,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+ add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[4], NodeFeatures::from_le_bytes(id_to_feature_flags(4)), 0);
+
+ add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(4)), 4);
+ update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 4,
+ timestamp: 1,
+ flags: 0,
+ cltv_expiry_delta: (4 << 8) | 0,
+ htlc_minimum_msat: 0,
+ htlc_maximum_msat: OptionalField::Absent,
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+ add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[3], NodeFeatures::from_le_bytes(id_to_feature_flags(3)), 0);
+
+ add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 3);
+ update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 3,
+ timestamp: 1,
+ flags: 0,
+ cltv_expiry_delta: (3 << 8) | 0,
+ htlc_minimum_msat: 0,
+ htlc_maximum_msat: OptionalField::Absent,
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+ add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[2], NodeFeatures::from_le_bytes(id_to_feature_flags(2)), 0);
+
+ add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(2)), 2);
+ update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 2,
+ timestamp: 1,
+ flags: 0,
+ cltv_expiry_delta: (2 << 8) | 0,
+ htlc_minimum_msat: 0,
+ htlc_maximum_msat: OptionalField::Absent,
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+
+ add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[6], ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), 1);
+ update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 1,
+ timestamp: 1,
+ flags: 0,
+ cltv_expiry_delta: (1 << 8) | 0,
+ htlc_minimum_msat: 100,
+ htlc_maximum_msat: OptionalField::Absent,
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+ add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[6], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0);
+
+ {
+ // Now ensure the route flows simply over nodes 1 and 4 to 6.
+ let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, None, &Vec::new(), 10_000, 42, Arc::clone(&logger)).unwrap();
+ assert_eq!(route.paths.len(), 1);
+ assert_eq!(route.paths[0].len(), 3);
+
+ assert_eq!(route.paths[0][0].pubkey, nodes[1]);
+ assert_eq!(route.paths[0][0].short_channel_id, 6);
+ assert_eq!(route.paths[0][0].fee_msat, 100);
+ assert_eq!(route.paths[0][0].cltv_expiry_delta, (5 << 8) | 0);
+ assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(1));
+ assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(6));
+
+ assert_eq!(route.paths[0][1].pubkey, nodes[4]);
+ assert_eq!(route.paths[0][1].short_channel_id, 5);
+ assert_eq!(route.paths[0][1].fee_msat, 0);
+ assert_eq!(route.paths[0][1].cltv_expiry_delta, (1 << 8) | 0);
+ assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(4));
+ assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(5));
+
+ assert_eq!(route.paths[0][2].pubkey, nodes[6]);
+ assert_eq!(route.paths[0][2].short_channel_id, 1);
+ assert_eq!(route.paths[0][2].fee_msat, 10_000);
+ assert_eq!(route.paths[0][2].cltv_expiry_delta, 42);
+ assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(6));
+ assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(1));
+ }
+ }
+
+
+ #[test]
+ fn exact_fee_liquidity_limit() {
+ // Test that if, while walking the graph, we find a hop that has exactly enough liquidity
+ // for us, including later hop fees, we take it. In the first version of our MPP algorithm
+ // we calculated fees on a higher value, resulting in us ignoring such paths.
+ let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
+ let (our_privkey, our_id, _, nodes) = get_nodes(&secp_ctx);
+
+ // We modify the graph to set the htlc_maximum of channel 2 to below the value we wish to
+ // send.
+ update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 2,
+ timestamp: 2,
+ flags: 0,
+ cltv_expiry_delta: 0,
+ htlc_minimum_msat: 0,
+ htlc_maximum_msat: OptionalField::Present(85_000),
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+
+ update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 12,
+ timestamp: 2,
+ flags: 0,
+ cltv_expiry_delta: (4 << 8) | 1,
+ htlc_minimum_msat: 0,
+ htlc_maximum_msat: OptionalField::Present(270_000),
+ fee_base_msat: 0,
+ fee_proportional_millionths: 1000000,
+ excess_data: Vec::new()
+ });
+
+ {
+ // Now, attempt to route 90 sats, which is exactly 90 sats at the last hop, plus the
+ // 200% fee charged channel 13 in the 1-to-2 direction.
+ let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, None, &Vec::new(), 90_000, 42, Arc::clone(&logger)).unwrap();
+ assert_eq!(route.paths.len(), 1);
+ assert_eq!(route.paths[0].len(), 2);
+
+ assert_eq!(route.paths[0][0].pubkey, nodes[7]);
+ assert_eq!(route.paths[0][0].short_channel_id, 12);
+ assert_eq!(route.paths[0][0].fee_msat, 90_000*2);
+ assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1);
+ assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(8));
+ assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(12));
+
+ assert_eq!(route.paths[0][1].pubkey, nodes[2]);
+ assert_eq!(route.paths[0][1].short_channel_id, 13);
+ assert_eq!(route.paths[0][1].fee_msat, 90_000);
+ assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
+ assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
+ assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13));
+ }
+ }
+
+ #[test]
+ fn htlc_max_reduction_below_min() {
+ // Test that if, while walking the graph, we reduce the value being sent to meet an
+ // htlc_maximum_msat, we don't end up undershooting a later htlc_minimum_msat. In the
+ // initial version of MPP we'd accept such routes but reject them while recalculating fees,
+ // resulting in us thinking there is no possible path, even if other paths exist.
+ let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
+ let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
+
+ // We modify the graph to set the htlc_minimum of channel 2 and 4 as needed - channel 2
+ // gets an htlc_maximum_msat of 80_000 and channel 4 an htlc_minimum_msat of 90_000. We
+ // then try to send 90_000.
+ update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 2,
+ timestamp: 2,
+ flags: 0,
+ cltv_expiry_delta: 0,
+ htlc_minimum_msat: 0,
+ htlc_maximum_msat: OptionalField::Present(80_000),
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+ update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+ chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+ short_channel_id: 4,
+ timestamp: 2,
+ flags: 0,
+ cltv_expiry_delta: (4 << 8) | 1,
+ htlc_minimum_msat: 90_000,
+ htlc_maximum_msat: OptionalField::Absent,
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ excess_data: Vec::new()
+ });
+
+ {
+ // Now, attempt to route 90 sats, hitting the htlc_minimum on channel 4, but
+ // overshooting the htlc_maximum on channel 2. Thus, we should pick the (absurdly
+ // expensive) channels 12-13 path.
+ let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], Some(InvoiceFeatures::known()), None, &Vec::new(), 90_000, 42, Arc::clone(&logger)).unwrap();
+ assert_eq!(route.paths.len(), 1);
+ assert_eq!(route.paths[0].len(), 2);
+
+ assert_eq!(route.paths[0][0].pubkey, nodes[7]);
+ assert_eq!(route.paths[0][0].short_channel_id, 12);
+ assert_eq!(route.paths[0][0].fee_msat, 90_000*2);
+ assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1);
+ assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(8));
+ assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(12));
+
+ assert_eq!(route.paths[0][1].pubkey, nodes[2]);
+ assert_eq!(route.paths[0][1].short_channel_id, 13);
+ assert_eq!(route.paths[0][1].fee_msat, 90_000);
+ assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
+ assert_eq!(route.paths[0][1].node_features.le_flags(), InvoiceFeatures::known().le_flags());
+ assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13));
+ }
+ }
+
+ #[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.
+ use core::hash::{BuildHasher, Hasher};
+ let seed = std::collections::hash_map::RandomState::new().build_hasher().finish();
+ println!("Using seed of {}", seed);
+ seed
+ }
+ #[cfg(not(feature = "no_std"))]
+ use util::ser::Readable;
+
+ #[test]
+ #[cfg(not(feature = "no_std"))]
+ fn generate_routes() {
+ let mut d = match super::test_utils::get_route_file() {
+ Ok(f) => f,
+ Err(e) => {
+ eprintln!("{}", e);
+ return;
+ },
+ };
+ let graph = NetworkGraph::read(&mut d).unwrap();
+
+ // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
+ let mut seed = random_init_seed() as usize;
+ 'load_endpoints: for _ in 0..10 {
+ loop {
+ seed = seed.overflowing_mul(0xdeadbeef).0;
+ let src = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap();
+ seed = seed.overflowing_mul(0xdeadbeef).0;
+ let dst = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap();
+ let amt = seed as u64 % 200_000_000;
+ if get_route(src, &graph, dst, None, None, &[], amt, 42, &test_utils::TestLogger::new()).is_ok() {
+ continue 'load_endpoints;
+ }
+ }
+ }
+ }
+
+ #[test]
+ #[cfg(not(feature = "no_std"))]
+ fn generate_routes_mpp() {
+ let mut d = match super::test_utils::get_route_file() {
+ Ok(f) => f,
+ Err(e) => {
+ eprintln!("{}", e);
+ return;
+ },
+ };
+ let graph = NetworkGraph::read(&mut d).unwrap();
+
+ // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
+ let mut seed = random_init_seed() as usize;
+ 'load_endpoints: for _ in 0..10 {
+ loop {
+ seed = seed.overflowing_mul(0xdeadbeef).0;
+ let src = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap();
+ seed = seed.overflowing_mul(0xdeadbeef).0;
+ let dst = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap();
+ let amt = seed as u64 % 200_000_000;
+ if get_route(src, &graph, dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &test_utils::TestLogger::new()).is_ok() {
+ continue 'load_endpoints;
+ }
+ }
+ }
+ }
+}
+
+#[cfg(all(test, not(feature = "no_std")))]
+pub(crate) mod test_utils {
+ use std::fs::File;
+ /// Tries to open a network graph file, or panics with a URL to fetch it.
+ pub(crate) fn get_route_file() -> Result<std::fs::File, &'static str> {
+ let res = File::open("net_graph-2021-05-31.bin") // By default we're run in RL/lightning
+ .or_else(|_| File::open("lightning/net_graph-2021-05-31.bin")) // We may be run manually in RL/
+ .or_else(|_| { // Fall back to guessing based on the binary location
+ // path is likely something like .../rust-lightning/target/debug/deps/lightning-...
+ let mut path = std::env::current_exe().unwrap();
+ path.pop(); // lightning-...
+ path.pop(); // deps
+ path.pop(); // debug
+ path.pop(); // target
+ path.push("lightning");
+ path.push("net_graph-2021-05-31.bin");
+ eprintln!("{}", path.to_str().unwrap());
+ File::open(path)
+ })
+ .map_err(|_| "Please fetch https://bitcoin.ninja/ldk-net_graph-v0.0.15-2021-05-31.bin and place it at lightning/net_graph-2021-05-31.bin");
+ #[cfg(require_route_graph_test)]
+ return Ok(res.unwrap());
+ #[cfg(not(require_route_graph_test))]
+ return res;
+ }
}
-#[cfg(all(test, feature = "unstable"))]
+#[cfg(all(test, feature = "unstable", not(feature = "no_std")))]
mod benches {
use super::*;
use util::logger::{Logger, Record};
- use std::fs::File;
use test::Bencher;
struct DummyLogger {}
#[bench]
fn generate_routes(bench: &mut Bencher) {
- let mut d = File::open("net_graph-2021-02-12.bin").expect("Please fetch https://bitcoin.ninja/ldk-net_graph-879e309c128-2020-02-12.bin and place it at lightning/net_graph-2021-02-12.bin");
+ let mut d = test_utils::get_route_file().unwrap();
let graph = NetworkGraph::read(&mut d).unwrap();
// First, get 100 (source, destination) pairs for which route-getting actually succeeds...
idx += 1;
});
}
+
+ #[bench]
+ fn generate_mpp_routes(bench: &mut Bencher) {
+ let mut d = test_utils::get_route_file().unwrap();
+ let graph = NetworkGraph::read(&mut d).unwrap();
+
+ // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
+ let mut path_endpoints = Vec::new();
+ let mut seed: usize = 0xdeadbeef;
+ 'load_endpoints: for _ in 0..100 {
+ loop {
+ seed *= 0xdeadbeef;
+ let src = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap();
+ seed *= 0xdeadbeef;
+ let dst = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap();
+ let amt = seed as u64 % 1_000_000;
+ if get_route(src, &graph, dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &DummyLogger{}).is_ok() {
+ path_endpoints.push((src, dst, amt));
+ continue 'load_endpoints;
+ }
+ }
+ }
+
+ // ...then benchmark finding paths between the nodes we learned.
+ let mut idx = 0;
+ bench.iter(|| {
+ let (src, dst, amt) = path_endpoints[idx % path_endpoints.len()];
+ assert!(get_route(src, &graph, dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &DummyLogger{}).is_ok());
+ idx += 1;
+ });
+ }
}
projects / rust-lightning / blobdiff