// Note that this function is not aware of the available_liquidity limit, and thus does not
// support increasing the value being transferred beyond what was selected during the initial
// routing passes.
- fn update_value_and_recompute_fees(&mut self, value_msat: u64) {
+ //
+ // Returns the amount that this path contributes to the total payment value, which may be greater
+ // than `value_msat` if we had to overpay to meet the final node's `htlc_minimum_msat`.
+ fn update_value_and_recompute_fees(&mut self, value_msat: u64) -> u64 {
+ let mut extra_contribution_msat = 0;
let mut total_fee_paid_msat = 0 as u64;
for i in (0..self.hops.len()).rev() {
let last_hop = i == self.hops.len() - 1;
let cur_hop = &mut self.hops.get_mut(i).unwrap().0;
cur_hop.next_hops_fee_msat = total_fee_paid_msat;
+ cur_hop.path_penalty_msat += extra_contribution_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
// set it too high just to maliciously take more fees by exploiting this
// Also, this can't be exploited more heavily than *announce a free path and fail
// all payments*.
cur_hop_transferred_amount_msat += extra_fees_msat;
- total_fee_paid_msat += extra_fees_msat;
- cur_hop_fees_msat += extra_fees_msat;
+
+ // We remember and return the extra fees on the final hop to allow accounting for
+ // them in the path's value contribution.
+ if last_hop {
+ extra_contribution_msat = extra_fees_msat;
+ } else {
+ total_fee_paid_msat += extra_fees_msat;
+ cur_hop_fees_msat += extra_fees_msat;
+ }
}
if last_hop {
}
}
}
+ value_msat + extra_contribution_msat
}
}
// recompute the fees again, so that if that's the case, we match the currently
// underpaid htlc_minimum_msat with fees.
debug_assert_eq!(payment_path.get_value_msat(), value_contribution_msat);
- value_contribution_msat = cmp::min(value_contribution_msat, final_value_msat);
- payment_path.update_value_and_recompute_fees(value_contribution_msat);
+ let desired_value_contribution = cmp::min(value_contribution_msat, final_value_msat);
+ value_contribution_msat = payment_path.update_value_and_recompute_fees(desired_value_contribution);
// Since a path allows to transfer as much value as
// the smallest channel it has ("bottleneck"), we should recompute
assert_eq!(err, "Failed to find a path to the given destination");
} else { panic!() }
}
+
+ #[test]
+ fn path_contribution_includes_min_htlc_overpay() {
+ // Previously, the fuzzer hit a debug panic because we wouldn't include the amount overpaid to
+ // meet a last hop's min_htlc in the total collected paths value. We now include this value and
+ // also penalize hops along the overpaying path to ensure that it gets deprioritized in path
+ // selection, both tested here.
+ let secp_ctx = Secp256k1::new();
+ let logger = Arc::new(ln_test_utils::TestLogger::new());
+ let network_graph = Arc::new(NetworkGraph::new(Network::Testnet, Arc::clone(&logger)));
+ let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), network_graph.clone(), logger.clone());
+ let keys_manager = ln_test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
+ let random_seed_bytes = keys_manager.get_secure_random_bytes();
+ let config = UserConfig::default();
+
+ // Values are taken from the fuzz input that uncovered this panic.
+ let amt_msat = 562_0000;
+ let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
+ let first_hops = vec![
+ get_channel_details(
+ Some(83), nodes[0], channelmanager::provided_init_features(&config), 2199_0000,
+ ),
+ ];
+
+ let htlc_mins = [49_0000, 1125_0000];
+ let payment_params = {
+ let blinded_path = BlindedPath {
+ introduction_node_id: nodes[0],
+ blinding_point: ln_test_utils::pubkey(42),
+ blinded_hops: vec![
+ BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
+ BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() }
+ ],
+ };
+ let mut blinded_hints = Vec::new();
+ for htlc_min in htlc_mins.iter() {
+ blinded_hints.push((BlindedPayInfo {
+ fee_base_msat: 0,
+ fee_proportional_millionths: 0,
+ htlc_minimum_msat: *htlc_min,
+ htlc_maximum_msat: *htlc_min * 100,
+ cltv_expiry_delta: 10,
+ features: BlindedHopFeatures::empty(),
+ }, blinded_path.clone()));
+ }
+ let bolt12_features: Bolt12InvoiceFeatures = channelmanager::provided_invoice_features(&config).to_context();
+ PaymentParameters::blinded(blinded_hints.clone())
+ .with_bolt12_features(bolt12_features.clone()).unwrap()
+ };
+
+ let netgraph = network_graph.read_only();
+ let route_params = RouteParameters::from_payment_params_and_value(
+ payment_params, amt_msat);
+ let route = get_route(
+ &our_id, &route_params, &netgraph, Some(&first_hops.iter().collect::<Vec<_>>()),
+ Arc::clone(&logger), &scorer, &ProbabilisticScoringFeeParameters::default(),
+ &random_seed_bytes
+ ).unwrap();
+ assert_eq!(route.paths.len(), 1);
+ assert_eq!(route.get_total_amount(), amt_msat);
+ }
}
#[cfg(all(any(test, ldk_bench), not(feature = "no-std")))]
projects / rust-lightning / commitdiff