Remove special case for onion error expiry_too_far

With channel scoring and payment retries, it is no longer necessary to
have expiry_too_far imply a payment failure.

Author: jkczyz

lightning/src/ln/onion_route_tests.rs

@@ -538,7 +538,7 @@ fn test_onion_failure() {
 		let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash);
 		msg.cltv_expiry = htlc_cltv;
 		msg.onion_routing_packet = onion_packet;
-	}, ||{}, true, Some(21), None);
+	}, ||{}, true, Some(21), Some(NetworkUpdate::NodeFailure{node_id: route.paths[0][0].pubkey, is_permanent: true}));
 }
 
 

lightning/src/ln/onion_utils.rs

@@ -377,11 +377,10 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(secp_ctx: &
 
 						// indicate that payment parameter has failed and no need to
 						// update Route object
-						let payment_failed = (match error_code & 0xff {
+						let payment_failed = match error_code & 0xff {
 							15|16|17|18|19 => true,
 							_ => false,
-						} && is_from_final_node) // PERM bit observed below even this error is from the intermediate nodes
-						|| error_code == 21; // Special case error 21 as the Route object is bogus, TODO: Maybe fail the node if the CLTV was reasonable?
+						} && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes
 
 						let mut network_update = None;