Merge pull request #2741 from shaavan/issue-2215

Explicitly reject routes that double-back

diff --git a/lightning/src/ln/functional_test_utils.rs b/lightning/src/ln/functional_test_utils.rs
index f48c9ec7059d2f7d07ad08d2498a2ce2f897337a..d3d2e3322cafb79f58573d6e18aa7deb84672709 100644 (file)
--- a/lightning/src/ln/functional_test_utils.rs
+++ b/lightning/src/ln/functional_test_utils.rs
@@ -956,7 +956,14 @@ macro_rules! unwrap_send_err {
                                        _ => panic!(),
                                }
                        },
-                       _ => panic!(),
+                       &Err(PaymentSendFailure::PathParameterError(ref result)) if !$all_failed => {
+                               assert_eq!(result.len(), 1);
+                               match result[0] {
+                                       Err($type) => { $check },
+                                       _ => panic!(),
+                               }
+                       },
+                       _ => {panic!()},
                }
        }
 }

diff --git a/lightning/src/ln/functional_tests.rs b/lightning/src/ln/functional_tests.rs
index 8e78f48e68561ecb8a861b14ae07866a76b2ff8b..450bc482c1a2dcbcf031be1f5f36a3304c945953 100644 (file)
--- a/lightning/src/ln/functional_tests.rs
+++ b/lightning/src/ln/functional_tests.rs
@@ -6205,6 +6205,30 @@ fn test_fail_holding_cell_htlc_upon_free_multihop() {
        check_added_monitors!(nodes[0], 1);
 }
 
+#[test]
+fn test_payment_route_reaching_same_channel_twice() {
+       //A route should not go through the same channel twice
+       //It is enforced when constructing a route.
+       let chanmon_cfgs = create_chanmon_cfgs(2);
+       let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+       let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+       let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+       let _chan = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1000000, 0);
+
+       let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), 0)
+               .with_bolt11_features(nodes[1].node.bolt11_invoice_features()).unwrap();
+       let (mut route, our_payment_hash, _, our_payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[1], payment_params, 100000000);
+
+       // Extend the path by itself, essentially simulating route going through same channel twice
+       let cloned_hops = route.paths[0].hops.clone();
+       route.paths[0].hops.extend_from_slice(&cloned_hops);
+
+       unwrap_send_err!(nodes[0].node.send_payment_with_route(&route, our_payment_hash,
+               RecipientOnionFields::secret_only(our_payment_secret), PaymentId(our_payment_hash.0)
+       ), false, APIError::InvalidRoute { ref err },
+       assert_eq!(err, &"Path went through the same channel twice"));
+}
+
 // BOLT 2 Requirements for the Sender when constructing and sending an update_add_htlc message.
 // BOLT 2 Requirement: MUST NOT offer amount_msat it cannot pay for in the remote commitment transaction at the current feerate_per_kw (see "Updating Fees") while maintaining its channel reserve.
 //TODO: I don't believe this is explicitly enforced when sending an HTLC but as the Fee aspect of the BOLT specs is in flux leaving this as a TODO.

diff --git a/lightning/src/ln/outbound_payment.rs b/lightning/src/ln/outbound_payment.rs
index b449e27983ecd09efdc88a90ff22235d0f7d0f67..e1748dca7f2ac11978035b2b44c4b66f8a2973d0 100644 (file)
--- a/lightning/src/ln/outbound_payment.rs
+++ b/lightning/src/ln/outbound_payment.rs
@@ -1337,6 +1337,13 @@ impl OutboundPayments {
                                        continue 'path_check;
                                }
                        }
+                       for (i, hop) in path.hops.iter().enumerate() {
+                               // Check for duplicate channel_id in the remaining hops of the path
+                               if path.hops.iter().skip(i + 1).any(|other_hop| other_hop.short_channel_id == hop.short_channel_id) {
+                                       path_errs.push(Err(APIError::InvalidRoute{err: "Path went through the same channel twice".to_owned()}));
+                                       continue 'path_check;
+                               }
+                       }
                        total_value += path.final_value_msat();
                        path_errs.push(Ok(()));
                }