/// participating node
/// * It is fine to cache `phantom_route_hints` and reuse it across invoices, as long as the data is
/// updated when a channel becomes disabled or closes
-/// * Note that if too many channels are included in [`PhantomRouteHints::channels`], the invoice
-/// may be too long for QR code scanning. To fix this, `PhantomRouteHints::channels` may be pared
-/// down
+/// * Note that the route hints generated from `phantom_route_hints` will be limited to a maximum
+/// of 3 hints to ensure that the invoice can be scanned in a QR code. These hints are selected
+/// in the order that the nodes in `PhantomRouteHints` are specified, selecting one hint per node
+/// until the maximum is hit. Callers may provide as many `PhantomRouteHints::channels` as
+/// desired, but note that some nodes will be trimmed if more than 3 nodes are provided.
///
/// `description_hash` is a SHA-256 hash of the description text
///
/// Utility to select route hints for phantom invoices.
/// See [`PhantomKeysManager`] for more information on phantom node payments.
-///
+///
+/// To ensure that the phantom invoice is still readable by QR code, we limit to 3 hints per invoice:
+/// * Select up to three channels per node.
+/// * Select one hint from each node, up to three hints or until we run out of hints.
+///
/// [`PhantomKeysManager`]: lightning::chain::keysinterface::PhantomKeysManager
fn select_phantom_hints<L: Deref>(amt_msat: Option<u64>, phantom_route_hints: Vec<PhantomRouteHints>,
logger: L) -> Vec<RouteHint>
where
L::Target: Logger,
{
- let mut phantom_hints: Vec<RouteHint> = Vec::new();
+ let mut phantom_hints: Vec<Vec<RouteHint>> = Vec::new();
for PhantomRouteHints { channels, phantom_scid, real_node_pubkey } in phantom_route_hints {
log_trace!(logger, "Generating phantom route hints for node {}",
if route_hints.is_empty() {
route_hints.push(RouteHint(vec![]))
}
- for mut route_hint in route_hints {
+ for route_hint in &mut route_hints {
route_hint.0.push(RouteHintHop {
src_node_id: real_node_pubkey,
short_channel_id: phantom_scid,
cltv_expiry_delta: MIN_CLTV_EXPIRY_DELTA,
htlc_minimum_msat: None,
htlc_maximum_msat: None,});
-
- phantom_hints.push(route_hint.clone());
}
+
+ phantom_hints.push(route_hints);
}
- phantom_hints
+ // We have one vector per real node involved in creating the phantom invoice. To distribute
+ // the hints across our real nodes we add one hint from each in turn until no node has any hints
+ // left (if one node has more hints than any other, these will accumulate at the end of the
+ // vector).
+ let mut invoice_hints: Vec<RouteHint> = Vec::new();
+ let mut hint_idx = 0;
+
+ loop {
+ let mut remaining_hints = false;
+
+ for hints in phantom_hints.iter() {
+ if invoice_hints.len() == 3 {
+ return invoice_hints
+ }
+
+ if hint_idx < hints.len() {
+ invoice_hints.push(hints[hint_idx].clone());
+ remaining_hints = true
+ }
+ }
+
+ if !remaining_hints {
+ return invoice_hints
+ }
+
+ hint_idx +=1;
+ }
}
#[cfg(feature = "std")]
);
}
- #[cfg(feature = "std")]
+ #[test]
+ fn test_multi_node_hints_limited_to_3() {
+ let mut chanmon_cfgs = create_chanmon_cfgs(6);
+ let seed_1 = [42 as u8; 32];
+ let seed_2 = [43 as u8; 32];
+ let seed_3 = [44 as u8; 32];
+ let seed_4 = [45 as u8; 32];
+ let cross_node_seed = [44 as u8; 32];
+ chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
+ chanmon_cfgs[3].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
+ chanmon_cfgs[4].keys_manager.backing = PhantomKeysManager::new(&seed_3, 43, 44, &cross_node_seed);
+ chanmon_cfgs[5].keys_manager.backing = PhantomKeysManager::new(&seed_4, 43, 44, &cross_node_seed);
+ let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);
+ let node_chanmgrs = create_node_chanmgrs(6, &node_cfgs, &[None, None, None, None, None, None]);
+ let nodes = create_network(6, &node_cfgs, &node_chanmgrs);
+
+ // Setup each phantom node with two channels from distinct peers.
+ let chan_0_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 10_000, 0);
+ let chan_1_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 2, 20_000, 0);
+ let chan_0_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 3, 20_000, 0);
+ let _chan_1_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 3, 10_000, 0);
+ let chan_0_4 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 4, 20_000, 0);
+ let _chan_1_4 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000, 0);
+ let _chan_0_5 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 5, 20_000, 0);
+ let _chan_1_5 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000, 0);
+
+ // Set invoice amount > all channels inbound so that every one is eligible for inclusion
+ // and hints will be sorted by largest inbound capacity.
+ let invoice_amt = Some(100_000_000);
+
+ // With 4 phantom nodes, assert that we include 1 hint per node, up to 3 nodes.
+ let mut scid_aliases = HashSet::new();
+ scid_aliases.insert(chan_1_2.0.short_channel_id_alias.unwrap());
+ scid_aliases.insert(chan_0_3.0.short_channel_id_alias.unwrap());
+ scid_aliases.insert(chan_0_4.0.short_channel_id_alias.unwrap());
+
+ match_multi_node_invoice_routes(
+ invoice_amt,
+ &nodes[3],
+ vec![&nodes[2], &nodes[3], &nodes[4], &nodes[5]],
+ scid_aliases,
+ false,
+ );
+
+ // With 2 phantom nodes, assert that we include no more than 3 hints.
+ let mut scid_aliases = HashSet::new();
+ scid_aliases.insert(chan_1_2.0.short_channel_id_alias.unwrap());
+ scid_aliases.insert(chan_0_3.0.short_channel_id_alias.unwrap());
+ scid_aliases.insert(chan_0_2.0.short_channel_id_alias.unwrap());
+
+ match_multi_node_invoice_routes(
+ invoice_amt,
+ &nodes[3],
+ vec![&nodes[2], &nodes[3]],
+ scid_aliases,
+ false,
+ );
+ }
+
+ #[test]
+ fn test_multi_node_hints_at_least_3() {
+ let mut chanmon_cfgs = create_chanmon_cfgs(5);
+ let seed_1 = [42 as u8; 32];
+ let seed_2 = [43 as u8; 32];
+ let cross_node_seed = [44 as u8; 32];
+ chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
+ chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
+ let node_cfgs = create_node_cfgs(5, &chanmon_cfgs);
+ let node_chanmgrs = create_node_chanmgrs(5, &node_cfgs, &[None, None, None, None, None]);
+ let nodes = create_network(5, &node_cfgs, &node_chanmgrs);
+
+ let _chan_0_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 3, 10_000, 0);
+ let chan_1_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 3, 20_000, 0);
+ let chan_2_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 30_000, 0);
+ let chan_0_4 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000, 0);
+
+ // Since the invoice amount is above all channels inbound, all four are eligible. Test that
+ // we still include 3 hints from 2 distinct nodes sorted by inbound.
+ let mut scid_aliases = HashSet::new();
+ scid_aliases.insert(chan_1_3.0.short_channel_id_alias.unwrap());
+ scid_aliases.insert(chan_2_3.0.short_channel_id_alias.unwrap());
+ scid_aliases.insert(chan_0_4.0.short_channel_id_alias.unwrap());
+
+ match_multi_node_invoice_routes(
+ Some(100_000_000),
+ &nodes[3],
+ vec![&nodes[3], &nodes[4],],
+ scid_aliases,
+ false,
+ );
+ }
+
fn match_multi_node_invoice_routes<'a, 'b: 'a, 'c: 'b>(
invoice_amt: Option<u64>,
invoice_node: &Node<'a, 'b, 'c>,
projects / rust-lightning / commitdiff