[rust-lightning] / lightning / src / ln / onion_route_tests.rs

// This file is Copyright its original authors, visible in version control
// history.
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.

//! Tests of the onion error messages/codes which are returned when routing a payment fails.
//! These tests work by standing up full nodes and route payments across the network, checking the
//! returned errors decode to the correct thing.

use ln::channelmanager::{HTLCForwardInfo, PaymentPreimage, PaymentHash};
use ln::channelmonitor::{CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS};
use ln::onion_utils;
use routing::router::{Route, get_route};
use ln::features::InitFeatures;
use ln::msgs;
use ln::msgs::{ChannelMessageHandler, HTLCFailChannelUpdate, OptionalField};
use util::test_utils;
use util::events::{Event, EventsProvider, MessageSendEvent, MessageSendEventsProvider};
use util::ser::{Writeable, Writer};
use util::config::UserConfig;

use bitcoin::blockdata::block::BlockHeader;
use bitcoin::hash_types::BlockHash;

use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hashes::Hash;

use bitcoin::secp256k1::Secp256k1;
use bitcoin::secp256k1::key::SecretKey;

use std::default::Default;
use std::sync::atomic::Ordering;
use std::io;

use ln::functional_test_utils::*;

fn run_onion_failure_test<F1,F2>(_name: &str, test_case: u8, nodes: &Vec<Node>, route: &Route, payment_hash: &PaymentHash, callback_msg: F1, callback_node: F2, expected_retryable: bool, expected_error_code: Option<u16>, expected_channel_update: Option<HTLCFailChannelUpdate>)
        where F1: for <'a> FnMut(&'a mut msgs::UpdateAddHTLC),
                                F2: FnMut(),
{
        run_onion_failure_test_with_fail_intercept(_name, test_case, nodes, route, payment_hash, callback_msg, |_|{}, callback_node, expected_retryable, expected_error_code, expected_channel_update);
}

// test_case
// 0: node1 fails backward
// 1: final node fails backward
// 2: payment completed but the user rejects the payment
// 3: final node fails backward (but tamper onion payloads from node0)
// 100: trigger error in the intermediate node and tamper returning fail_htlc
// 200: trigger error in the final node and tamper returning fail_htlc
fn run_onion_failure_test_with_fail_intercept<F1,F2,F3>(_name: &str, test_case: u8, nodes: &Vec<Node>, route: &Route, payment_hash: &PaymentHash, mut callback_msg: F1, mut callback_fail: F2, mut callback_node: F3, expected_retryable: bool, expected_error_code: Option<u16>, expected_channel_update: Option<HTLCFailChannelUpdate>)
        where F1: for <'a> FnMut(&'a mut msgs::UpdateAddHTLC),
                                F2: for <'a> FnMut(&'a mut msgs::UpdateFailHTLC),
                                F3: FnMut(),
{

        // reset block height
        let header = BlockHeader { version: 0x20000000, prev_blockhash: Default::default(), merkle_root: Default::default(), time: 42, bits: 42, nonce: 42 };
        for ix in 0..nodes.len() {
                nodes[ix].block_notifier.block_connected_checked(&header, 1, &[], &[]);
        }

        macro_rules! expect_event {
                ($node: expr, $event_type: path) => {{
                        let events = $node.node.get_and_clear_pending_events();
                        assert_eq!(events.len(), 1);
                        match events[0] {
                                $event_type { .. } => {},
                                _ => panic!("Unexpected event"),
                        }
                }}
        }

        macro_rules! expect_htlc_forward {
                ($node: expr) => {{
                        expect_event!($node, Event::PendingHTLCsForwardable);
                        $node.node.process_pending_htlc_forwards();
                }}
        }

        // 0 ~~> 2 send payment
        nodes[0].node.send_payment(&route, payment_hash.clone(), &None).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        // temper update_add (0 => 1)
        let mut update_add_0 = update_0.update_add_htlcs[0].clone();
        if test_case == 0 || test_case == 3 || test_case == 100 {
                callback_msg(&mut update_add_0);
                callback_node();
        }
        // 0 => 1 update_add & CS
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add_0);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        let update_1_0 = match test_case {
                0|100 => { // intermediate node failure; fail backward to 0
                        let update_1_0 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
                        assert!(update_1_0.update_fail_htlcs.len()+update_1_0.update_fail_malformed_htlcs.len()==1 && (update_1_0.update_fail_htlcs.len()==1 || update_1_0.update_fail_malformed_htlcs.len()==1));
                        update_1_0
                },
                1|2|3|200 => { // final node failure; forwarding to 2
                        assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
                        // forwarding on 1
                        if test_case != 200 {
                                callback_node();
                        }
                        expect_htlc_forward!(&nodes[1]);

                        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[2].node.get_our_node_id());
                        check_added_monitors!(&nodes[1], 1);
                        assert_eq!(update_1.update_add_htlcs.len(), 1);
                        // tamper update_add (1 => 2)
                        let mut update_add_1 = update_1.update_add_htlcs[0].clone();
                        if test_case != 3 && test_case != 200 {
                                callback_msg(&mut update_add_1);
                        }

                        // 1 => 2
                        nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &update_add_1);
                        commitment_signed_dance!(nodes[2], nodes[1], update_1.commitment_signed, false, true);

                        if test_case == 2 || test_case == 200 {
                                expect_htlc_forward!(&nodes[2]);
                                expect_event!(&nodes[2], Event::PaymentReceived);
                                callback_node();
                                expect_pending_htlcs_forwardable!(nodes[2]);
                        }

                        let update_2_1 = get_htlc_update_msgs!(nodes[2], nodes[1].node.get_our_node_id());
                        if test_case == 2 || test_case == 200 {
                                check_added_monitors!(&nodes[2], 1);
                        }
                        assert!(update_2_1.update_fail_htlcs.len() == 1);

                        let mut fail_msg = update_2_1.update_fail_htlcs[0].clone();
                        if test_case == 200 {
                                callback_fail(&mut fail_msg);
                        }

                        // 2 => 1
                        nodes[1].node.handle_update_fail_htlc(&nodes[2].node.get_our_node_id(), &fail_msg);
                        commitment_signed_dance!(nodes[1], nodes[2], update_2_1.commitment_signed, true);

                        // backward fail on 1
                        let update_1_0 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
                        assert!(update_1_0.update_fail_htlcs.len() == 1);
                        update_1_0
                },
                _ => unreachable!(),
        };

        // 1 => 0 commitment_signed_dance
        if update_1_0.update_fail_htlcs.len() > 0 {
                let mut fail_msg = update_1_0.update_fail_htlcs[0].clone();
                if test_case == 100 {
                        callback_fail(&mut fail_msg);
                }
                nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        } else {
                nodes[0].node.handle_update_fail_malformed_htlc(&nodes[1].node.get_our_node_id(), &update_1_0.update_fail_malformed_htlcs[0]);
        };

        commitment_signed_dance!(nodes[0], nodes[1], update_1_0.commitment_signed, false, true);

        let events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        if let &Event::PaymentFailed { payment_hash:_, ref rejected_by_dest, ref error_code, error_data: _ } = &events[0] {
                assert_eq!(*rejected_by_dest, !expected_retryable);
                assert_eq!(*error_code, expected_error_code);
        } else {
                panic!("Uexpected event");
        }

        let events = nodes[0].node.get_and_clear_pending_msg_events();
        if expected_channel_update.is_some() {
                assert_eq!(events.len(), 1);
                match events[0] {
                        MessageSendEvent::PaymentFailureNetworkUpdate { ref update } => {
                                match update {
                                        &HTLCFailChannelUpdate::ChannelUpdateMessage { .. } => {
                                                if let HTLCFailChannelUpdate::ChannelUpdateMessage { .. } = expected_channel_update.unwrap() {} else {
                                                        panic!("channel_update not found!");
                                                }
                                        },
                                        &HTLCFailChannelUpdate::ChannelClosed { ref short_channel_id, ref is_permanent } => {
                                                if let HTLCFailChannelUpdate::ChannelClosed { short_channel_id: ref expected_short_channel_id, is_permanent: ref expected_is_permanent } = expected_channel_update.unwrap() {
                                                        assert!(*short_channel_id == *expected_short_channel_id);
                                                        assert!(*is_permanent == *expected_is_permanent);
                                                } else {
                                                        panic!("Unexpected message event");
                                                }
                                        },
                                        &HTLCFailChannelUpdate::NodeFailure { ref node_id, ref is_permanent } => {
                                                if let HTLCFailChannelUpdate::NodeFailure { node_id: ref expected_node_id, is_permanent: ref expected_is_permanent } = expected_channel_update.unwrap() {
                                                        assert!(*node_id == *expected_node_id);
                                                        assert!(*is_permanent == *expected_is_permanent);
                                                } else {
                                                        panic!("Unexpected message event");
                                                }
                                        },
                                }
                        },
                        _ => panic!("Unexpected message event"),
                }
        } else {
                assert_eq!(events.len(), 0);
        }
}

impl msgs::ChannelUpdate {
        fn dummy() -> msgs::ChannelUpdate {
                use bitcoin::secp256k1::ffi::Signature as FFISignature;
                use bitcoin::secp256k1::Signature;
                msgs::ChannelUpdate {
                        signature: Signature::from(FFISignature::new()),
                        contents: msgs::UnsignedChannelUpdate {
                                chain_hash: BlockHash::hash(&vec![0u8][..]),
                                short_channel_id: 0,
                                timestamp: 0,
                                flags: 0,
                                cltv_expiry_delta: 0,
                                htlc_minimum_msat: 0,
                                htlc_maximum_msat: OptionalField::Absent,
                                fee_base_msat: 0,
                                fee_proportional_millionths: 0,
                                excess_data: vec![],
                        }
                }
        }
}

struct BogusOnionHopData {
        data: Vec<u8>
}
impl BogusOnionHopData {
        fn new(orig: msgs::OnionHopData) -> Self {
                Self { data: orig.encode() }
        }
}
impl Writeable for BogusOnionHopData {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                writer.write_all(&self.data[..])
        }
}

#[test]
fn test_onion_failure() {
        use ln::msgs::ChannelUpdate;
        use ln::channelmanager::CLTV_FAR_FAR_AWAY;
        use bitcoin::secp256k1;

        const BADONION: u16 = 0x8000;
        const PERM: u16 = 0x4000;
        const NODE: u16 = 0x2000;
        const UPDATE: u16 = 0x1000;

        // When we check for amount_below_minimum below, we want to test that we're using the *right*
        // amount, thus we need different htlc_minimum_msat values. We set node[2]'s htlc_minimum_msat
        // to 2000, which is above the default value of 1000 set in create_node_chanmgrs.
        // This exposed a previous bug because we were using the wrong value all the way down in
        // Channel::get_counterparty_htlc_minimum_msat().
        let mut node_2_cfg: UserConfig = Default::default();
        node_2_cfg.own_channel_config.our_htlc_minimum_msat = 2000;
        node_2_cfg.channel_options.announced_channel = true;
        node_2_cfg.peer_channel_config_limits.force_announced_channel_preference = false;

        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, Some(node_2_cfg)]);
        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);
        for node in nodes.iter() {
                *node.keys_manager.override_session_priv.lock().unwrap() = Some([3; 32]);
        }
        let channels = [create_announced_chan_between_nodes(&nodes, 0, 1, InitFeatures::known(), InitFeatures::known()), create_announced_chan_between_nodes(&nodes, 1, 2, InitFeatures::known(), InitFeatures::known())];
        let (_, payment_hash) = get_payment_preimage_hash!(nodes[0]);
        let net_graph_msg_handler = &nodes[0].net_graph_msg_handler;
        let logger = test_utils::TestLogger::new();
        let route = get_route(&nodes[0].node.get_our_node_id(), &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2].node.get_our_node_id(), None, &Vec::new(), 40000, TEST_FINAL_CLTV, &logger).unwrap();
        // positve case
        send_payment(&nodes[0], &vec!(&nodes[1], &nodes[2])[..], 40000, 40_000);

        // intermediate node failure
        run_onion_failure_test("invalid_realm", 0, &nodes, &route, &payment_hash, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let cur_height = nodes[0].node.latest_block_height.load(Ordering::Acquire) as u32 + 1;
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                let (mut onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(&route.paths[0], 40000, &None, cur_height).unwrap();
                let mut new_payloads = Vec::new();
                for payload in onion_payloads.drain(..) {
                        new_payloads.push(BogusOnionHopData::new(payload));
                }
                // break the first (non-final) hop payload by swapping the realm (0) byte for a byte
                // describing a length-1 TLV payload, which is obviously bogus.
                new_payloads[0].data[0] = 1;
                msg.onion_routing_packet = onion_utils::construct_onion_packet_bogus_hopdata(new_payloads, onion_keys, [0; 32], &payment_hash);
        }, ||{}, true, Some(PERM|22), Some(msgs::HTLCFailChannelUpdate::ChannelClosed{short_channel_id: channels[1].0.contents.short_channel_id, is_permanent: true}));//XXX incremented channels idx here

        // final node failure
        run_onion_failure_test("invalid_realm", 3, &nodes, &route, &payment_hash, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let cur_height = nodes[0].node.latest_block_height.load(Ordering::Acquire) as u32 + 1;
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                let (mut onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(&route.paths[0], 40000, &None, cur_height).unwrap();
                let mut new_payloads = Vec::new();
                for payload in onion_payloads.drain(..) {
                        new_payloads.push(BogusOnionHopData::new(payload));
                }
                // break the last-hop payload by swapping the realm (0) byte for a byte describing a
                // length-1 TLV payload, which is obviously bogus.
                new_payloads[1].data[0] = 1;
                msg.onion_routing_packet = onion_utils::construct_onion_packet_bogus_hopdata(new_payloads, onion_keys, [0; 32], &payment_hash);
        }, ||{}, false, Some(PERM|22), Some(msgs::HTLCFailChannelUpdate::ChannelClosed{short_channel_id: channels[1].0.contents.short_channel_id, is_permanent: true}));

        // the following three with run_onion_failure_test_with_fail_intercept() test only the origin node
        // receiving simulated fail messages
        // intermediate node failure
        run_onion_failure_test_with_fail_intercept("temporary_node_failure", 100, &nodes, &route, &payment_hash, |msg| {
                // trigger error
                msg.amount_msat -= 1;
        }, |msg| {
                // and tamper returning error message
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[0].shared_secret[..], NODE|2, &[0;0]);
        }, ||{}, true, Some(NODE|2), Some(msgs::HTLCFailChannelUpdate::NodeFailure{node_id: route.paths[0][0].pubkey, is_permanent: false}));

        // final node failure
        run_onion_failure_test_with_fail_intercept("temporary_node_failure", 200, &nodes, &route, &payment_hash, |_msg| {}, |msg| {
                // and tamper returning error message
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[1].shared_secret[..], NODE|2, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash, &None);
        }, true, Some(NODE|2), Some(msgs::HTLCFailChannelUpdate::NodeFailure{node_id: route.paths[0][1].pubkey, is_permanent: false}));

        // intermediate node failure
        run_onion_failure_test_with_fail_intercept("permanent_node_failure", 100, &nodes, &route, &payment_hash, |msg| {
                msg.amount_msat -= 1;
        }, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[0].shared_secret[..], PERM|NODE|2, &[0;0]);
        }, ||{}, true, Some(PERM|NODE|2), Some(msgs::HTLCFailChannelUpdate::NodeFailure{node_id: route.paths[0][0].pubkey, is_permanent: true}));

        // final node failure
        run_onion_failure_test_with_fail_intercept("permanent_node_failure", 200, &nodes, &route, &payment_hash, |_msg| {}, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[1].shared_secret[..], PERM|NODE|2, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash, &None);
        }, false, Some(PERM|NODE|2), Some(msgs::HTLCFailChannelUpdate::NodeFailure{node_id: route.paths[0][1].pubkey, is_permanent: true}));

        // intermediate node failure
        run_onion_failure_test_with_fail_intercept("required_node_feature_missing", 100, &nodes, &route, &payment_hash, |msg| {
                msg.amount_msat -= 1;
        }, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[0].shared_secret[..], PERM|NODE|3, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash, &None);
        }, true, Some(PERM|NODE|3), Some(msgs::HTLCFailChannelUpdate::NodeFailure{node_id: route.paths[0][0].pubkey, is_permanent: true}));

        // final node failure
        run_onion_failure_test_with_fail_intercept("required_node_feature_missing", 200, &nodes, &route, &payment_hash, |_msg| {}, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[1].shared_secret[..], PERM|NODE|3, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash, &None);
        }, false, Some(PERM|NODE|3), Some(msgs::HTLCFailChannelUpdate::NodeFailure{node_id: route.paths[0][1].pubkey, is_permanent: true}));

        run_onion_failure_test("invalid_onion_version", 0, &nodes, &route, &payment_hash, |msg| { msg.onion_routing_packet.version = 1; }, ||{}, true,
                Some(BADONION|PERM|4), None);

        run_onion_failure_test("invalid_onion_hmac", 0, &nodes, &route, &payment_hash, |msg| { msg.onion_routing_packet.hmac = [3; 32]; }, ||{}, true,
                Some(BADONION|PERM|5), None);

        run_onion_failure_test("invalid_onion_key", 0, &nodes, &route, &payment_hash, |msg| { msg.onion_routing_packet.public_key = Err(secp256k1::Error::InvalidPublicKey);}, ||{}, true,
                Some(BADONION|PERM|6), None);

        run_onion_failure_test_with_fail_intercept("temporary_channel_failure", 100, &nodes, &route, &payment_hash, |msg| {
                msg.amount_msat -= 1;
        }, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[0].shared_secret[..], UPDATE|7, &ChannelUpdate::dummy().encode_with_len()[..]);
        }, ||{}, true, Some(UPDATE|7), Some(msgs::HTLCFailChannelUpdate::ChannelUpdateMessage{msg: ChannelUpdate::dummy()}));

        run_onion_failure_test_with_fail_intercept("permanent_channel_failure", 100, &nodes, &route, &payment_hash, |msg| {
                msg.amount_msat -= 1;
        }, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[0].shared_secret[..], PERM|8, &[0;0]);
                // short_channel_id from the processing node
        }, ||{}, true, Some(PERM|8), Some(msgs::HTLCFailChannelUpdate::ChannelClosed{short_channel_id: channels[1].0.contents.short_channel_id, is_permanent: true}));

        run_onion_failure_test_with_fail_intercept("required_channel_feature_missing", 100, &nodes, &route, &payment_hash, |msg| {
                msg.amount_msat -= 1;
        }, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                msg.reason = onion_utils::build_first_hop_failure_packet(&onion_keys[0].shared_secret[..], PERM|9, &[0;0]);
                // short_channel_id from the processing node
        }, ||{}, true, Some(PERM|9), Some(msgs::HTLCFailChannelUpdate::ChannelClosed{short_channel_id: channels[1].0.contents.short_channel_id, is_permanent: true}));

        let mut bogus_route = route.clone();
        bogus_route.paths[0][1].short_channel_id -= 1;
        run_onion_failure_test("unknown_next_peer", 0, &nodes, &bogus_route, &payment_hash, |_| {}, ||{}, true, Some(PERM|10),
          Some(msgs::HTLCFailChannelUpdate::ChannelClosed{short_channel_id: bogus_route.paths[0][1].short_channel_id, is_permanent:true}));

        let amt_to_forward = nodes[1].node.channel_state.lock().unwrap().by_id.get(&channels[1].2).unwrap().get_counterparty_htlc_minimum_msat() - 1;
        let mut bogus_route = route.clone();
        let route_len = bogus_route.paths[0].len();
        bogus_route.paths[0][route_len-1].fee_msat = amt_to_forward;
        run_onion_failure_test("amount_below_minimum", 0, &nodes, &bogus_route, &payment_hash, |_| {}, ||{}, true, Some(UPDATE|11), Some(msgs::HTLCFailChannelUpdate::ChannelUpdateMessage{msg: ChannelUpdate::dummy()}));

        // Test a positive test-case with one extra msat, meeting the minimum.
        bogus_route.paths[0][route_len-1].fee_msat = amt_to_forward + 1;
        let (preimage, _) = send_along_route(&nodes[0], bogus_route, &[&nodes[1], &nodes[2]], amt_to_forward+1);
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], preimage, amt_to_forward+1);

        //TODO: with new config API, we will be able to generate both valid and
        //invalid channel_update cases.
        run_onion_failure_test("fee_insufficient", 0, &nodes, &route, &payment_hash, |msg| {
                msg.amount_msat -= 1;
        }, || {}, true, Some(UPDATE|12), Some(msgs::HTLCFailChannelUpdate::ChannelClosed { short_channel_id: channels[0].0.contents.short_channel_id, is_permanent: true}));

        run_onion_failure_test("incorrect_cltv_expiry", 0, &nodes, &route, &payment_hash, |msg| {
                // need to violate: cltv_expiry - cltv_expiry_delta >= outgoing_cltv_value
                msg.cltv_expiry -= 1;
        }, || {}, true, Some(UPDATE|13), Some(msgs::HTLCFailChannelUpdate::ChannelClosed { short_channel_id: channels[0].0.contents.short_channel_id, is_permanent: true}));

        run_onion_failure_test("expiry_too_soon", 0, &nodes, &route, &payment_hash, |msg| {
                let height = msg.cltv_expiry - CLTV_CLAIM_BUFFER - LATENCY_GRACE_PERIOD_BLOCKS + 1;
                let header = BlockHeader { version: 0x20000000, prev_blockhash: Default::default(), merkle_root: Default::default(), time: 42, bits: 42, nonce: 42 };

                nodes[1].block_notifier.block_connected_checked(&header, height, &[], &[]);
        }, ||{}, true, Some(UPDATE|14), Some(msgs::HTLCFailChannelUpdate::ChannelUpdateMessage{msg: ChannelUpdate::dummy()}));

        run_onion_failure_test("unknown_payment_hash", 2, &nodes, &route, &payment_hash, |_| {}, || {
                nodes[2].node.fail_htlc_backwards(&payment_hash, &None);
        }, false, Some(PERM|15), None);

        run_onion_failure_test("final_expiry_too_soon", 1, &nodes, &route, &payment_hash, |msg| {
                let height = msg.cltv_expiry - CLTV_CLAIM_BUFFER - LATENCY_GRACE_PERIOD_BLOCKS + 1;
                let header = BlockHeader { version: 0x20000000, prev_blockhash: Default::default(), merkle_root: Default::default(), time: 42, bits: 42, nonce: 42 };

                nodes[2].block_notifier.block_connected_checked(&header, height, &[], &[]);
        }, || {}, true, Some(17), None);

        run_onion_failure_test("final_incorrect_cltv_expiry", 1, &nodes, &route, &payment_hash, |_| {}, || {
                for (_, pending_forwards) in nodes[1].node.channel_state.lock().unwrap().forward_htlcs.iter_mut() {
                        for f in pending_forwards.iter_mut() {
                                match f {
                                        &mut HTLCForwardInfo::AddHTLC { ref mut forward_info, .. } =>
                                                forward_info.outgoing_cltv_value += 1,
                                        _ => {},
                                }
                        }
                }
        }, true, Some(18), None);

        run_onion_failure_test("final_incorrect_htlc_amount", 1, &nodes, &route, &payment_hash, |_| {}, || {
                // violate amt_to_forward > msg.amount_msat
                for (_, pending_forwards) in nodes[1].node.channel_state.lock().unwrap().forward_htlcs.iter_mut() {
                        for f in pending_forwards.iter_mut() {
                                match f {
                                        &mut HTLCForwardInfo::AddHTLC { ref mut forward_info, .. } =>
                                                forward_info.amt_to_forward -= 1,
                                        _ => {},
                                }
                        }
                }
        }, true, Some(19), None);

        run_onion_failure_test("channel_disabled", 0, &nodes, &route, &payment_hash, |_| {}, || {
                // disconnect event to the channel between nodes[1] ~ nodes[2]
                nodes[1].node.peer_disconnected(&nodes[2].node.get_our_node_id(), false);
                nodes[2].node.peer_disconnected(&nodes[1].node.get_our_node_id(), false);
        }, true, Some(UPDATE|20), Some(msgs::HTLCFailChannelUpdate::ChannelUpdateMessage{msg: ChannelUpdate::dummy()}));
        reconnect_nodes(&nodes[1], &nodes[2], (false, false), (0, 0), (0, 0), (0, 0), (0, 0), (false, false));

        run_onion_failure_test("expiry_too_far", 0, &nodes, &route, &payment_hash, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let mut route = route.clone();
                let height = 1;
                route.paths[0][1].cltv_expiry_delta += CLTV_FAR_FAR_AWAY + route.paths[0][0].cltv_expiry_delta + 1;
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                let (onion_payloads, _, htlc_cltv) = onion_utils::build_onion_payloads(&route.paths[0], 40000, &None, height).unwrap();
                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);
}