node_info.features.supports_basic_mpp()
} else { false }
} else { false };
+ log_trace!(logger, "Searching for a route from payer {} to payee {} {} MPP", our_node_id, payee,
+ if allow_mpp { "with" } else { "without" });
// Step (1).
// 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<_, (_, ChannelFeatures, _, NodeFeatures)> =
+ let mut first_hop_targets: HashMap<_, Vec<(_, 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 {
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.counterparty.node_id, (short_channel_id, chan.counterparty.features.to_context(), chan.outbound_capacity_msat, chan.counterparty.features.to_context()));
+ first_hop_targets.entry(chan.counterparty.node_id).or_insert(Vec::new())
+ .push((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});
};
if !skip_node {
- if first_hops.is_some() {
- if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat, _)) = first_hop_targets.get(&$node_id) {
+ if let Some(first_channels) = first_hop_targets.get(&$node_id) {
+ for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
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);
}
}
// 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, 0, path_value_msat, 0);
+ if let Some(first_channels) = first_hop_targets.get(&payee) {
+ for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
+ let added = add_entry!(first_hop, *our_node_id, payee, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, 0, path_value_msat, 0);
+ log_trace!(logger, "{} direct route to payee via SCID {}", if added { "Added" } else { "Skipped" }, first_hop);
}
}
},
}
- // Step (1).
+ // Step (2).
// If a caller provided us with last hops, add them to routing targets. Since this happens
// earlier than general path finding, they will be somewhat prioritized, although currently
// it matters only if the fees are exactly the same.
}
// Searching for a direct channel between last checked hop and first_hop_targets
- if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat, _)) = first_hop_targets.get(&prev_hop_id) {
- add_entry!(first_hop, *our_node_id , prev_hop_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat);
+ if let Some(first_channels) = first_hop_targets.get(&prev_hop_id) {
+ for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
+ add_entry!(first_hop, *our_node_id , prev_hop_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat);
+ }
}
if !hop_used {
// 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, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat);
+ if let Some(first_channels) = first_hop_targets.get(&hop.src_node_id) {
+ for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
+ add_entry!(first_hop, *our_node_id , hop.src_node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat);
+ }
}
}
}
// last hops communicated by the caller, and the payment receiver.
let mut found_new_path = false;
- // Step (2).
+ // Step (3).
// If this loop terminates due the exhaustion of targets, two situations are possible:
// - not enough outgoing liquidity:
// 0 < already_collected_value_msat < final_value_msat
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().0.pubkey) {
- ordered_hops.last_mut().unwrap().1 = features.clone();
- } else if let Some(node) = network_nodes.get(&ordered_hops.last().unwrap().0.pubkey) {
- if let Some(node_info) = node.announcement_info.as_ref() {
- ordered_hops.last_mut().unwrap().1 = node_info.features.clone();
+ let mut features_set = false;
+ if let Some(first_channels) = first_hop_targets.get(&ordered_hops.last().unwrap().0.pubkey) {
+ for (scid, _, _, ref features) in first_channels {
+ if *scid == ordered_hops.last().unwrap().0.short_channel_id {
+ ordered_hops.last_mut().unwrap().1 = features.clone();
+ features_set = true;
+ break;
+ }
+ }
+ }
+ if !features_set {
+ if let Some(node) = network_nodes.get(&ordered_hops.last().unwrap().0.pubkey) {
+ if let Some(node_info) = node.announcement_info.as_ref() {
+ ordered_hops.last_mut().unwrap().1 = node_info.features.clone();
+ } else {
+ ordered_hops.last_mut().unwrap().1 = NodeFeatures::empty();
+ }
} else {
- ordered_hops.last_mut().unwrap().1 = NodeFeatures::empty();
+ // 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().0.pubkey == *payee);
}
- } 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().0.pubkey == *payee);
}
// Means we succesfully traversed from the payer to the payee, now
break 'paths_collection;
}
- // Step (3).
+ // Step (4).
// 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,
}
}
- // Step (4).
+ // Step (5).
if payment_paths.len() == 0 {
return Err(LightningError{err: "Failed to find a path to the given destination".to_owned(), action: ErrorAction::IgnoreError});
}
let mut cur_route = Vec::<PaymentPath>::new();
let mut aggregate_route_value_msat = 0;
- // Step (5).
+ // Step (6).
// TODO: real random shuffle
// Currently just starts with i_th and goes up to i-1_th in a looped way.
let cur_payment_paths = [&payment_paths[i..], &payment_paths[..i]].concat();
- // Step (6).
+ // Step (7).
for payment_path in cur_payment_paths {
cur_route.push(payment_path.clone());
aggregate_route_value_msat += payment_path.get_value_msat();
assert!(cur_route.len() > 0);
- // Step (7).
+ // Step (8).
// 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.
drawn_routes.push(cur_route);
}
- // Step (8).
+ // Step (9).
// Select the best route by lowest total fee.
drawn_routes.sort_by_key(|paths| paths.iter().map(|path| path.get_total_fee_paid_msat()).sum::<u64>());
let mut selected_paths = Vec::<Vec<RouteHop>>::new();
}
}
+ #[test]
+ fn multiple_direct_first_hops() {
+ // Previously we'd only ever considered one first hop path per counterparty.
+ // However, as we don't restrict users to one channel per peer, we really need to support
+ // looking at all first hop paths.
+ // Here we test that we do not ignore all-but-the-last first hop paths per counterparty (as
+ // we used to do by overwriting the `first_hop_targets` hashmap entry) and that we can MPP
+ // route over multiple channels with the same first hop.
+ let secp_ctx = Secp256k1::new();
+ let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
+ let logger = Arc::new(test_utils::TestLogger::new());
+ let network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
+
+ {
+ let route = get_route(&our_id, &network_graph, &nodes[0], Some(InvoiceFeatures::known()), Some(&[
+ &get_channel_details(Some(3), nodes[0], InitFeatures::known(), 200_000),
+ &get_channel_details(Some(2), nodes[0], InitFeatures::known(), 10_000),
+ ]), &[], 100_000, 42, Arc::clone(&logger)).unwrap();
+ assert_eq!(route.paths.len(), 1);
+ assert_eq!(route.paths[0].len(), 1);
+
+ assert_eq!(route.paths[0][0].pubkey, nodes[0]);
+ assert_eq!(route.paths[0][0].short_channel_id, 3);
+ assert_eq!(route.paths[0][0].fee_msat, 100_000);
+ }
+ {
+ let route = get_route(&our_id, &network_graph, &nodes[0], Some(InvoiceFeatures::known()), Some(&[
+ &get_channel_details(Some(3), nodes[0], InitFeatures::known(), 50_000),
+ &get_channel_details(Some(2), nodes[0], InitFeatures::known(), 50_000),
+ ]), &[], 100_000, 42, Arc::clone(&logger)).unwrap();
+ assert_eq!(route.paths.len(), 2);
+ assert_eq!(route.paths[0].len(), 1);
+ assert_eq!(route.paths[1].len(), 1);
+
+ assert_eq!(route.paths[0][0].pubkey, nodes[0]);
+ assert_eq!(route.paths[0][0].short_channel_id, 3);
+ assert_eq!(route.paths[0][0].fee_msat, 50_000);
+
+ assert_eq!(route.paths[1][0].pubkey, nodes[0]);
+ assert_eq!(route.paths[1][0].short_channel_id, 2);
+ assert_eq!(route.paths[1][0].fee_msat, 50_000);
+ }
+ }
+
#[test]
fn total_fees_single_path() {
let route = Route {
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