Merge pull request #3144 from TheBlueMatt/2024-06-message-flags

[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 crate::chain::channelmonitor::{CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS};
use crate::sign::{EntropySource, NodeSigner, Recipient};
use crate::events::{Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentFailureReason};
use crate::ln::types::{PaymentHash, PaymentSecret};
use crate::ln::channel::EXPIRE_PREV_CONFIG_TICKS;
use crate::ln::channelmanager::{HTLCForwardInfo, FailureCode, CLTV_FAR_FAR_AWAY, DISABLE_GOSSIP_TICKS, MIN_CLTV_EXPIRY_DELTA, PendingAddHTLCInfo, PendingHTLCInfo, PendingHTLCRouting, PaymentId, RecipientOnionFields};
use crate::ln::onion_utils;
use crate::routing::gossip::{NetworkUpdate, RoutingFees};
use crate::routing::router::{get_route, PaymentParameters, Route, RouteParameters, RouteHint, RouteHintHop};
use crate::ln::features::{InitFeatures, Bolt11InvoiceFeatures};
use crate::ln::functional_test_utils::test_default_channel_config;
use crate::ln::msgs;
use crate::ln::msgs::{ChannelMessageHandler, ChannelUpdate, OutboundTrampolinePayload};
use crate::ln::wire::Encode;
use crate::util::ser::{Writeable, Writer, BigSize};
use crate::util::test_utils;
use crate::util::config::{UserConfig, ChannelConfig, MaxDustHTLCExposure};
use crate::util::errors::APIError;

use bitcoin::blockdata::constants::ChainHash;
use bitcoin::hashes::{Hash, HashEngine};
use bitcoin::hashes::hmac::{Hmac, HmacEngine};
use bitcoin::hashes::sha256::Hash as Sha256;

use bitcoin::secp256k1;
use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};

use crate::io;
use crate::prelude::*;
use bitcoin::hashes::hex::FromHex;

use crate::ln::functional_test_utils::*;

fn run_onion_failure_test<F1,F2>(_name: &str, test_case: u8, nodes: &Vec<Node>, route: &Route, payment_hash: &PaymentHash, payment_secret: &PaymentSecret, callback_msg: F1, callback_node: F2, expected_retryable: bool, expected_error_code: Option<u16>, expected_channel_update: Option<NetworkUpdate>, expected_short_channel_id: Option<u64>)
        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, payment_secret, callback_msg, |_|{}, callback_node, expected_retryable, expected_error_code, expected_channel_update, expected_short_channel_id);
}

// 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,
        payment_secret: &PaymentSecret, mut callback_msg: F1, mut callback_fail: F2,
        mut callback_node: F3, expected_retryable: bool, expected_error_code: Option<u16>,
        expected_channel_update: Option<NetworkUpdate>, expected_short_channel_id: Option<u64>
)
        where F1: for <'a> FnMut(&'a mut msgs::UpdateAddHTLC),
                                F2: for <'a> FnMut(&'a mut msgs::UpdateFailHTLC),
                                F3: FnMut(),
{
        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
        let payment_id = PaymentId(nodes[0].keys_manager.backing.get_secure_random_bytes());
        nodes[0].node.send_payment_with_route(&route, *payment_hash,
                RecipientOnionFields::secret_only(*payment_secret), payment_id).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::PaymentClaimable);
                                callback_node();
                                expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[2], vec![HTLCDestination::FailedPayment { payment_hash: payment_hash.clone() }]);
                        }

                        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(), 2);
        if let &Event::PaymentPathFailed { ref payment_failed_permanently, ref short_channel_id, ref error_code, failure: PathFailure::OnPath { ref network_update }, .. } = &events[0] {
                assert_eq!(*payment_failed_permanently, !expected_retryable);
                assert_eq!(*error_code, expected_error_code);
                if expected_channel_update.is_some() {
                        match network_update {
                                Some(update) => match update {
                                        &NetworkUpdate::ChannelFailure { ref short_channel_id, ref is_permanent } => {
                                                if let NetworkUpdate::ChannelFailure { 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");
                                                }
                                        },
                                        &NetworkUpdate::NodeFailure { ref node_id, ref is_permanent } => {
                                                if let NetworkUpdate::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");
                                                }
                                        },
                                }
                                None => panic!("Expected channel update"),
                        }
                } else {
                        assert!(network_update.is_none());
                }
                if let Some(expected_short_channel_id) = expected_short_channel_id {
                        match short_channel_id {
                                Some(short_channel_id) => assert_eq!(*short_channel_id, expected_short_channel_id),
                                None => panic!("Expected short channel id"),
                        }
                } else {
                        assert!(short_channel_id.is_none());
                }
        } else {
                panic!("Unexpected event");
        }
        match events[1] {
                Event::PaymentFailed { payment_hash: ev_payment_hash, payment_id: ev_payment_id, reason: ref ev_reason } => {
                        assert_eq!(*payment_hash, ev_payment_hash);
                        assert_eq!(payment_id, ev_payment_id);
                        assert_eq!(if expected_retryable {
                                PaymentFailureReason::RetriesExhausted
                        } else {
                                PaymentFailureReason::RecipientRejected
                        }, ev_reason.unwrap());
                }
                _ => panic!("Unexpected second event"),
        }
}

impl msgs::ChannelUpdate {
        fn dummy(short_channel_id: u64) -> msgs::ChannelUpdate {
                use bitcoin::hash_types::BlockHash;
                use bitcoin::secp256k1::ffi::Signature as FFISignature;
                use bitcoin::secp256k1::ecdsa::Signature;
                msgs::ChannelUpdate {
                        signature: Signature::from(unsafe { FFISignature::new() }),
                        contents: msgs::UnsignedChannelUpdate {
                                chain_hash: ChainHash::from(BlockHash::hash(&vec![0u8][..]).as_ref()),
                                short_channel_id,
                                timestamp: 0,
                                flags: 0,
                                cltv_expiry_delta: 0,
                                htlc_minimum_msat: 0,
                                htlc_maximum_msat: msgs::MAX_VALUE_MSAT,
                                fee_base_msat: 0,
                                fee_proportional_millionths: 0,
                                excess_data: vec![],
                        }
                }
        }
}

struct BogusOnionHopData {
        data: Vec<u8>
}
impl BogusOnionHopData {
        fn new(orig: msgs::OutboundOnionPayload) -> 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[..])
        }
}

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

#[test]
fn test_fee_failures() {
        // Tests that the fee required when forwarding remains consistent over time. This was
        // previously broken, with forwarding fees floating based on the fee estimator at the time of
        // forwarding.
        //
        // When this test was written, the default base fee floated based on the HTLC count.
        // It is now fixed, so we simply set the fee to the expected value here.
        let mut config = test_default_channel_config();
        config.channel_config.forwarding_fee_base_msat = 196;

        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, &[Some(config), Some(config), Some(config)]);
        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);
        let channels = [create_announced_chan_between_nodes(&nodes, 0, 1), create_announced_chan_between_nodes(&nodes, 1, 2)];

        // positive case
        let (route, payment_hash_success, payment_preimage_success, payment_secret_success) = get_route_and_payment_hash!(nodes[0], nodes[2], 40_000);
        nodes[0].node.send_payment_with_route(&route, payment_hash_success,
                RecipientOnionFields::secret_only(payment_secret_success), PaymentId(payment_hash_success.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        pass_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], 40_000, payment_hash_success, payment_secret_success);
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage_success);

        // If the hop gives fee_insufficient but enough fees were provided, then the previous hop
        // malleated the payment before forwarding, taking funds when they shouldn't have. However,
        // because we ignore channel update contents, we will still blame the 2nd channel.
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[2]);
        let short_channel_id = channels[1].0.contents.short_channel_id;
        run_onion_failure_test("fee_insufficient", 0, &nodes, &route, &payment_hash, &payment_secret, |msg| {
                msg.amount_msat -= 1;
        }, || {}, true, Some(UPDATE|12), Some(NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false}), Some(short_channel_id));

        // In an earlier version, we spuriously failed to forward payments if the expected feerate
        // changed between the channel open and the payment.
        {
                let mut feerate_lock = chanmon_cfgs[1].fee_estimator.sat_per_kw.lock().unwrap();
                *feerate_lock *= 2;
        }

        let (payment_preimage_success, payment_hash_success, payment_secret_success) = get_payment_preimage_hash!(nodes[2]);
        nodes[0].node.send_payment_with_route(&route, payment_hash_success,
                RecipientOnionFields::secret_only(payment_secret_success), PaymentId(payment_hash_success.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        pass_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], 40_000, payment_hash_success, payment_secret_success);
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage_success);
}

#[test]
fn test_onion_failure() {
        // 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 = test_default_channel_config();
        node_2_cfg.channel_handshake_config.our_htlc_minimum_msat = 2000;
        node_2_cfg.channel_handshake_config.announced_channel = true;
        node_2_cfg.channel_handshake_limits.force_announced_channel_preference = false;

        // When this test was written, the default base fee floated based on the HTLC count.
        // It is now fixed, so we simply set the fee to the expected value here.
        let mut config = test_default_channel_config();
        config.channel_config.forwarding_fee_base_msat = 196;

        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, &[Some(config), Some(config), Some(node_2_cfg)]);
        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);
        let channels = [create_announced_chan_between_nodes(&nodes, 0, 1), create_announced_chan_between_nodes(&nodes, 1, 2)];
        for node in nodes.iter() {
                *node.keys_manager.override_random_bytes.lock().unwrap() = Some([3; 32]);
        }
        let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[2], 40000);
        // positive case
        send_payment(&nodes[0], &vec!(&nodes[1], &nodes[2])[..], 40000);

        // intermediate node failure
        let short_channel_id = channels[1].0.contents.short_channel_id;
        run_onion_failure_test("invalid_realm", 0, &nodes, &route, &payment_hash, &payment_secret, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let cur_height = nodes[0].best_block_info().1 + 1;
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
                let (mut onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
                        &route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).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_with_writable_hopdata(new_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
        }, ||{}, true, Some(PERM|22), Some(NetworkUpdate::ChannelFailure{short_channel_id, is_permanent: true}), Some(short_channel_id));

        // final node failure
        let short_channel_id = channels[1].0.contents.short_channel_id;
        run_onion_failure_test("invalid_realm", 3, &nodes, &route, &payment_hash, &payment_secret, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let cur_height = nodes[0].best_block_info().1 + 1;
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
                let (mut onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
                        &route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).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_with_writable_hopdata(new_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
        }, ||{}, false, Some(PERM|22), Some(NetworkUpdate::ChannelFailure{short_channel_id, is_permanent: true}), Some(short_channel_id));

        // 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, &payment_secret, |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.as_ref(), NODE|2, &[0;0]);
        }, ||{}, true, Some(NODE|2), Some(NetworkUpdate::NodeFailure{node_id: route.paths[0].hops[0].pubkey, is_permanent: false}), Some(route.paths[0].hops[0].short_channel_id));

        // final node failure
        run_onion_failure_test_with_fail_intercept("temporary_node_failure", 200, &nodes, &route, &payment_hash, &payment_secret, |_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.as_ref(), NODE|2, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash);
        }, true, Some(NODE|2), Some(NetworkUpdate::NodeFailure{node_id: route.paths[0].hops[1].pubkey, is_permanent: false}), Some(route.paths[0].hops[1].short_channel_id));
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[2]);

        // intermediate node failure
        run_onion_failure_test_with_fail_intercept("permanent_node_failure", 100, &nodes, &route, &payment_hash, &payment_secret, |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.as_ref(), PERM|NODE|2, &[0;0]);
        }, ||{}, true, Some(PERM|NODE|2), Some(NetworkUpdate::NodeFailure{node_id: route.paths[0].hops[0].pubkey, is_permanent: true}), Some(route.paths[0].hops[0].short_channel_id));

        // final node failure
        run_onion_failure_test_with_fail_intercept("permanent_node_failure", 200, &nodes, &route, &payment_hash, &payment_secret, |_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.as_ref(), PERM|NODE|2, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash);
        }, false, Some(PERM|NODE|2), Some(NetworkUpdate::NodeFailure{node_id: route.paths[0].hops[1].pubkey, is_permanent: true}), Some(route.paths[0].hops[1].short_channel_id));
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[2]);

        // intermediate node failure
        run_onion_failure_test_with_fail_intercept("required_node_feature_missing", 100, &nodes, &route, &payment_hash, &payment_secret, |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.as_ref(), PERM|NODE|3, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash);
        }, true, Some(PERM|NODE|3), Some(NetworkUpdate::NodeFailure{node_id: route.paths[0].hops[0].pubkey, is_permanent: true}), Some(route.paths[0].hops[0].short_channel_id));

        // final node failure
        run_onion_failure_test_with_fail_intercept("required_node_feature_missing", 200, &nodes, &route, &payment_hash, &payment_secret, |_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.as_ref(), PERM|NODE|3, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash);
        }, false, Some(PERM|NODE|3), Some(NetworkUpdate::NodeFailure{node_id: route.paths[0].hops[1].pubkey, is_permanent: true}), Some(route.paths[0].hops[1].short_channel_id));
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[2]);

        // Our immediate peer sent UpdateFailMalformedHTLC because it couldn't understand the onion in
        // the UpdateAddHTLC that we sent.
        let short_channel_id = channels[0].0.contents.short_channel_id;
        run_onion_failure_test("invalid_onion_version", 0, &nodes, &route, &payment_hash, &payment_secret, |msg| { msg.onion_routing_packet.version = 1; }, ||{}, true,
                Some(BADONION|PERM|4), None, Some(short_channel_id));

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

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

        let short_channel_id = channels[1].0.contents.short_channel_id;
        let chan_update = ChannelUpdate::dummy(short_channel_id);

        let mut err_data = Vec::new();
        err_data.extend_from_slice(&(chan_update.serialized_length() as u16 + 2).to_be_bytes());
        err_data.extend_from_slice(&ChannelUpdate::TYPE.to_be_bytes());
        err_data.extend_from_slice(&chan_update.encode());
        run_onion_failure_test_with_fail_intercept("temporary_channel_failure", 100, &nodes, &route, &payment_hash, &payment_secret, |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.as_ref(), UPDATE|7, &err_data);
        }, ||{}, true, Some(UPDATE|7),
        Some(NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false }),
        Some(short_channel_id));

        // Check we can still handle onion failures that include channel updates without a type prefix
        let err_data_without_type = chan_update.encode_with_len();
        run_onion_failure_test_with_fail_intercept("temporary_channel_failure", 100, &nodes, &route, &payment_hash, &payment_secret, |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.as_ref(), UPDATE|7, &err_data_without_type);
        }, ||{}, true, Some(UPDATE|7),
        Some(NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false }),
        Some(short_channel_id));

        let short_channel_id = channels[1].0.contents.short_channel_id;
        run_onion_failure_test_with_fail_intercept("permanent_channel_failure", 100, &nodes, &route, &payment_hash, &payment_secret, |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.as_ref(), PERM|8, &[0;0]);
                // short_channel_id from the processing node
        }, ||{}, true, Some(PERM|8), Some(NetworkUpdate::ChannelFailure{short_channel_id, is_permanent: true}), Some(short_channel_id));

        let short_channel_id = channels[1].0.contents.short_channel_id;
        run_onion_failure_test_with_fail_intercept("required_channel_feature_missing", 100, &nodes, &route, &payment_hash, &payment_secret, |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.as_ref(), PERM|9, &[0;0]);
                // short_channel_id from the processing node
        }, ||{}, true, Some(PERM|9), Some(NetworkUpdate::ChannelFailure{short_channel_id, is_permanent: true}), Some(short_channel_id));

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

        let short_channel_id = channels[1].0.contents.short_channel_id;
        let amt_to_forward = nodes[1].node.per_peer_state.read().unwrap().get(&nodes[2].node.get_our_node_id())
                .unwrap().lock().unwrap().channel_by_id.get(&channels[1].2).unwrap()
                .context().get_counterparty_htlc_minimum_msat() - 1;
        let mut bogus_route = route.clone();
        let route_len = bogus_route.paths[0].hops.len();
        bogus_route.paths[0].hops[route_len-1].fee_msat = amt_to_forward;
        run_onion_failure_test("amount_below_minimum", 0, &nodes, &bogus_route, &payment_hash, &payment_secret, |_| {}, ||{}, true, Some(UPDATE|11),
                Some(NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false }),
                Some(short_channel_id));

        // Clear pending payments so that the following positive test has the correct payment hash.
        for node in nodes.iter() {
                node.node.clear_pending_payments();
        }

        // Test a positive test-case with one extra msat, meeting the minimum.
        bogus_route.paths[0].hops[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).0;
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], preimage);

        // We ignore channel update contents in onion errors, so will blame the 2nd channel even though
        // the first node is the one that messed up.
        let short_channel_id = channels[1].0.contents.short_channel_id;
        run_onion_failure_test("fee_insufficient", 0, &nodes, &route, &payment_hash, &payment_secret, |msg| {
                msg.amount_msat -= 1;
        }, || {}, true, Some(UPDATE|12), Some(NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false}), Some(short_channel_id));

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

        let short_channel_id = channels[1].0.contents.short_channel_id;
        run_onion_failure_test("expiry_too_soon", 0, &nodes, &route, &payment_hash, &payment_secret, |msg| {
                let height = msg.cltv_expiry - CLTV_CLAIM_BUFFER - LATENCY_GRACE_PERIOD_BLOCKS + 1;
                connect_blocks(&nodes[0], height - nodes[0].best_block_info().1);
                connect_blocks(&nodes[1], height - nodes[1].best_block_info().1);
                connect_blocks(&nodes[2], height - nodes[2].best_block_info().1);
        }, ||{}, true, Some(UPDATE|14),
        Some(NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false }),
        Some(short_channel_id));

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

        run_onion_failure_test("final_expiry_too_soon", 1, &nodes, &route, &payment_hash, &payment_secret, |msg| {
                let height = msg.cltv_expiry - CLTV_CLAIM_BUFFER - LATENCY_GRACE_PERIOD_BLOCKS + 1;
                connect_blocks(&nodes[0], height - nodes[0].best_block_info().1);
                connect_blocks(&nodes[1], height - nodes[1].best_block_info().1);
                connect_blocks(&nodes[2], height - nodes[2].best_block_info().1);
        }, || {}, false, Some(0x4000 | 15), None, None);

        run_onion_failure_test("final_incorrect_cltv_expiry", 1, &nodes, &route, &payment_hash, &payment_secret, |_| {}, || {
                for (_, pending_forwards) in nodes[1].node.forward_htlcs.lock().unwrap().iter_mut() {
                        for f in pending_forwards.iter_mut() {
                                match f {
                                        &mut HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo { ref mut forward_info, .. }) =>
                                                forward_info.outgoing_cltv_value -= 1,
                                        _ => {},
                                }
                        }
                }
        }, true, Some(18), None, Some(channels[1].0.contents.short_channel_id));

        run_onion_failure_test("final_incorrect_htlc_amount", 1, &nodes, &route, &payment_hash, &payment_secret, |_| {}, || {
                // violate amt_to_forward > msg.amount_msat
                for (_, pending_forwards) in nodes[1].node.forward_htlcs.lock().unwrap().iter_mut() {
                        for f in pending_forwards.iter_mut() {
                                match f {
                                        &mut HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo { ref mut forward_info, .. }) =>
                                                forward_info.outgoing_amt_msat -= 1,
                                        _ => {},
                                }
                        }
                }
        }, true, Some(19), None, Some(channels[1].0.contents.short_channel_id));

        let short_channel_id = channels[1].0.contents.short_channel_id;
        run_onion_failure_test("channel_disabled", 0, &nodes, &route, &payment_hash, &payment_secret, |_| {}, || {
                // disconnect event to the channel between nodes[1] ~ nodes[2]
                nodes[1].node.peer_disconnected(&nodes[2].node.get_our_node_id());
                nodes[2].node.peer_disconnected(&nodes[1].node.get_our_node_id());
        }, true, Some(UPDATE|7),
        Some(NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false }),
        Some(short_channel_id));
        run_onion_failure_test("channel_disabled", 0, &nodes, &route, &payment_hash, &payment_secret, |_| {}, || {
                // disconnect event to the channel between nodes[1] ~ nodes[2]
                for _ in 0..DISABLE_GOSSIP_TICKS + 1 {
                        nodes[1].node.timer_tick_occurred();
                        nodes[2].node.timer_tick_occurred();
                }
                nodes[1].node.get_and_clear_pending_msg_events();
                nodes[2].node.get_and_clear_pending_msg_events();
        }, true, Some(UPDATE|20),
        Some(NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false }),
        Some(short_channel_id));
        reconnect_nodes(ReconnectArgs::new(&nodes[1], &nodes[2]));

        run_onion_failure_test("expiry_too_far", 0, &nodes, &route, &payment_hash, &payment_secret, |msg| {
                let session_priv = SecretKey::from_slice(&[3; 32]).unwrap();
                let mut route = route.clone();
                let height = nodes[2].best_block_info().1;
                route.paths[0].hops[1].cltv_expiry_delta += CLTV_FAR_FAR_AWAY + route.paths[0].hops[0].cltv_expiry_delta + 1;
                let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
                let (onion_payloads, _, htlc_cltv) = onion_utils::build_onion_payloads(
                        &route.paths[0], 40000, &recipient_onion_fields, height, &None).unwrap();
                let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
                msg.cltv_expiry = htlc_cltv;
                msg.onion_routing_packet = onion_packet;
        }, ||{}, true, Some(21), Some(NetworkUpdate::NodeFailure{node_id: route.paths[0].hops[0].pubkey, is_permanent: true}), Some(route.paths[0].hops[0].short_channel_id));

        run_onion_failure_test_with_fail_intercept("mpp_timeout", 200, &nodes, &route, &payment_hash, &payment_secret, |_msg| {}, |msg| {
                // 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.as_ref(), 23, &[0;0]);
        }, ||{
                nodes[2].node.fail_htlc_backwards(&payment_hash);
        }, true, Some(23), None, None);

        run_onion_failure_test_with_fail_intercept("bogus err packet with valid hmac", 200, &nodes,
                &route, &payment_hash, &payment_secret, |_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();
                        let mut decoded_err_packet = msgs::DecodedOnionErrorPacket {
                                failuremsg: vec![0],
                                pad: vec![0; 255],
                                hmac: [0; 32],
                        };
                        let um = onion_utils::gen_um_from_shared_secret(&onion_keys[1].shared_secret.as_ref());
                        let mut hmac = HmacEngine::<Sha256>::new(&um);
                        hmac.input(&decoded_err_packet.encode()[32..]);
                        decoded_err_packet.hmac = Hmac::from_engine(hmac).to_byte_array();
                        msg.reason = onion_utils::encrypt_failure_packet(
                                &onion_keys[1].shared_secret.as_ref(), &decoded_err_packet.encode()[..])
                }, || nodes[2].node.fail_htlc_backwards(&payment_hash), false, None,
                Some(NetworkUpdate::NodeFailure { node_id: route.paths[0].hops[1].pubkey, is_permanent: true }),
                Some(channels[1].0.contents.short_channel_id));
        run_onion_failure_test_with_fail_intercept("0-length channel update in intermediate node UPDATE onion failure",
                100, &nodes, &route, &payment_hash, &payment_secret, |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();
                        let mut decoded_err_packet = msgs::DecodedOnionErrorPacket {
                                failuremsg: vec![
                                        0x10, 0x7, // UPDATE|7
                                        0x0, 0x0 // 0-len channel update
                                ],
                                pad: vec![0; 255 - 4 /* 4-byte error message */],
                                hmac: [0; 32],
                        };
                        let um = onion_utils::gen_um_from_shared_secret(&onion_keys[0].shared_secret.as_ref());
                        let mut hmac = HmacEngine::<Sha256>::new(&um);
                        hmac.input(&decoded_err_packet.encode()[32..]);
                        decoded_err_packet.hmac = Hmac::from_engine(hmac).to_byte_array();
                        msg.reason = onion_utils::encrypt_failure_packet(
                                &onion_keys[0].shared_secret.as_ref(), &decoded_err_packet.encode()[..])
                }, || {}, true, Some(0x1000|7),
                Some(NetworkUpdate::ChannelFailure {
                        short_channel_id: channels[1].0.contents.short_channel_id,
                        is_permanent: false,
                }),
                Some(channels[1].0.contents.short_channel_id));
        run_onion_failure_test_with_fail_intercept("0-length channel update in final node UPDATE onion failure",
                200, &nodes, &route, &payment_hash, &payment_secret, |_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();
                        let mut decoded_err_packet = msgs::DecodedOnionErrorPacket {
                                failuremsg: vec![
                                        0x10, 0x7, // UPDATE|7
                                        0x0, 0x0 // 0-len channel update
                                ],
                                pad: vec![0; 255 - 4 /* 4-byte error message */],
                                hmac: [0; 32],
                        };
                        let um = onion_utils::gen_um_from_shared_secret(&onion_keys[1].shared_secret.as_ref());
                        let mut hmac = HmacEngine::<Sha256>::new(&um);
                        hmac.input(&decoded_err_packet.encode()[32..]);
                        decoded_err_packet.hmac = Hmac::from_engine(hmac).to_byte_array();
                        msg.reason = onion_utils::encrypt_failure_packet(
                                &onion_keys[1].shared_secret.as_ref(), &decoded_err_packet.encode()[..])
                }, || nodes[2].node.fail_htlc_backwards(&payment_hash), true, Some(0x1000|7),
                Some(NetworkUpdate::ChannelFailure {
                        short_channel_id: channels[1].0.contents.short_channel_id,
                        is_permanent: false,
                }),
                Some(channels[1].0.contents.short_channel_id));
}

#[test]
fn test_overshoot_final_cltv() {
        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; 3]);
        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);
        create_announced_chan_between_nodes(&nodes, 0, 1);
        create_announced_chan_between_nodes(&nodes, 1, 2);
        let (route, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[2], 40000);

        let payment_id = PaymentId(nodes[0].keys_manager.backing.get_secure_random_bytes());
        nodes[0].node.send_payment_with_route(&route, payment_hash, RecipientOnionFields::secret_only(payment_secret), payment_id).unwrap();

        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add_0 = update_0.update_add_htlcs[0].clone();
        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);

        assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
        for (_, pending_forwards) in nodes[1].node.forward_htlcs.lock().unwrap().iter_mut() {
                for f in pending_forwards.iter_mut() {
                        match f {
                                &mut HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo { ref mut forward_info, .. }) =>
                                        forward_info.outgoing_cltv_value += 1,
                                _ => {},
                        }
                }
        }
        expect_pending_htlcs_forwardable!(nodes[1]);

        check_added_monitors!(&nodes[1], 1);
        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[2].node.get_our_node_id());
        let mut update_add_1 = update_1.update_add_htlcs[0].clone();
        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);

        expect_pending_htlcs_forwardable!(nodes[2]);
        expect_payment_claimable!(nodes[2], payment_hash, payment_secret, 40_000);
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage);
}

fn do_test_onion_failure_stale_channel_update(announced_channel: bool) {
        // Create a network of three nodes and two channels connecting them. We'll be updating the
        // HTLC relay policy of the second channel, causing forwarding failures at the first hop.
        let mut config = UserConfig::default();
        config.channel_handshake_config.announced_channel = announced_channel;
        config.channel_handshake_limits.force_announced_channel_preference = false;
        config.accept_forwards_to_priv_channels = !announced_channel;
        config.channel_config.max_dust_htlc_exposure = MaxDustHTLCExposure::FeeRateMultiplier(5_000_000 / 253);
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let persister;
        let chain_monitor;
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, Some(config), None]);
        let channel_manager_1_deserialized;
        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        let other_channel = create_chan_between_nodes(
                &nodes[0], &nodes[1],
        );
        let channel_to_update = if announced_channel {
                let channel = create_announced_chan_between_nodes(
                        &nodes, 1, 2,
                );
                (channel.2, channel.0.contents.short_channel_id)
        } else {
                let channel = create_unannounced_chan_between_nodes_with_value(
                        &nodes, 1, 2, 100000, 10001,
                );
                (channel.0.channel_id, channel.0.short_channel_id_alias.unwrap())
        };
        let channel_to_update_counterparty = &nodes[2].node.get_our_node_id();

        let default_config = ChannelConfig::default();

        // A test payment should succeed as the ChannelConfig has not been changed yet.
        const PAYMENT_AMT: u64 = 40000;
        let (route, payment_hash, payment_preimage, payment_secret) = if announced_channel {
                get_route_and_payment_hash!(nodes[0], nodes[2], PAYMENT_AMT)
        } else {
                let hop_hints = vec![RouteHint(vec![RouteHintHop {
                        src_node_id: nodes[1].node.get_our_node_id(),
                        short_channel_id: channel_to_update.1,
                        fees: RoutingFees {
                                base_msat: default_config.forwarding_fee_base_msat,
                                proportional_millionths: default_config.forwarding_fee_proportional_millionths,
                        },
                        cltv_expiry_delta: default_config.cltv_expiry_delta,
                        htlc_maximum_msat: None,
                        htlc_minimum_msat: None,
                }])];
                let payment_params = PaymentParameters::from_node_id(*channel_to_update_counterparty, TEST_FINAL_CLTV)
                        .with_bolt11_features(nodes[2].node.bolt11_invoice_features()).unwrap()
                        .with_route_hints(hop_hints).unwrap();
                get_route_and_payment_hash!(nodes[0], nodes[2], payment_params, PAYMENT_AMT)
        };
        send_along_route_with_secret(&nodes[0], route.clone(), &[&[&nodes[1], &nodes[2]]], PAYMENT_AMT,
                payment_hash, payment_secret);
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage);

        // Closure to force expiry of a channel's previous config.
        let expire_prev_config = || {
                for _ in 0..EXPIRE_PREV_CONFIG_TICKS {
                        nodes[1].node.timer_tick_occurred();
                }
        };

        // Closure to update and retrieve the latest ChannelUpdate.
        let update_and_get_channel_update = |config: &ChannelConfig, expect_new_update: bool,
                prev_update: Option<&msgs::ChannelUpdate>, should_expire_prev_config: bool| -> Option<msgs::ChannelUpdate> {
                nodes[1].node.update_channel_config(
                        channel_to_update_counterparty, &[channel_to_update.0], config,
                ).unwrap();
                let events = nodes[1].node.get_and_clear_pending_msg_events();
                assert_eq!(events.len(), expect_new_update as usize);
                if !expect_new_update {
                        return None;
                }
                let new_update = match &events[0] {
                        MessageSendEvent::BroadcastChannelUpdate { msg } => {
                                assert!(announced_channel);
                                msg.clone()
                        },
                        MessageSendEvent::SendChannelUpdate { node_id, msg } => {
                                assert_eq!(node_id, channel_to_update_counterparty);
                                assert!(!announced_channel);
                                msg.clone()
                        },
                        _ => panic!("expected Broadcast/SendChannelUpdate event"),
                };
                if prev_update.is_some() {
                        assert!(new_update.contents.timestamp > prev_update.unwrap().contents.timestamp)
                }
                if should_expire_prev_config {
                        expire_prev_config();
                }
                Some(new_update)
        };

        // We'll be attempting to route payments using the default ChannelUpdate for channels. This will
        // lead to onion failures at the first hop once we update the ChannelConfig for the
        // second hop.
        let expect_onion_failure = |name: &str, error_code: u16| {
                let short_channel_id = channel_to_update.1;
                let network_update = NetworkUpdate::ChannelFailure { short_channel_id, is_permanent: false };
                run_onion_failure_test(
                        name, 0, &nodes, &route, &payment_hash, &payment_secret, |_| {}, || {}, true,
                        Some(error_code), Some(network_update), Some(short_channel_id),
                );
        };

        // Updates to cltv_expiry_delta below MIN_CLTV_EXPIRY_DELTA should fail with APIMisuseError.
        let mut invalid_config = default_config.clone();
        invalid_config.cltv_expiry_delta = 0;
        match nodes[1].node.update_channel_config(
                channel_to_update_counterparty, &[channel_to_update.0], &invalid_config,
        ) {
                Err(APIError::APIMisuseError{ .. }) => {},
                _ => panic!("unexpected result applying invalid cltv_expiry_delta"),
        }

        // Increase the base fee which should trigger a new ChannelUpdate.
        let mut config = nodes[1].node.list_usable_channels().iter()
                .find(|channel| channel.channel_id == channel_to_update.0).unwrap()
                .config.unwrap();
        config.forwarding_fee_base_msat = u32::max_value();
        let msg = update_and_get_channel_update(&config, true, None, false).unwrap();

        // The old policy should still be in effect until a new block is connected.
        send_along_route_with_secret(&nodes[0], route.clone(), &[&[&nodes[1], &nodes[2]]], PAYMENT_AMT,
                payment_hash, payment_secret);
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage);

        // Connect a block, which should expire the previous config, leading to a failure when
        // forwarding the HTLC.
        expire_prev_config();
        expect_onion_failure("fee_insufficient", UPDATE|12);

        // Redundant updates should not trigger a new ChannelUpdate.
        assert!(update_and_get_channel_update(&config, false, None, false).is_none());

        // Similarly, updates that do not have an affect on ChannelUpdate should not trigger a new one.
        config.force_close_avoidance_max_fee_satoshis *= 2;
        assert!(update_and_get_channel_update(&config, false, None, false).is_none());

        // Reset the base fee to the default and increase the proportional fee which should trigger a
        // new ChannelUpdate.
        config.forwarding_fee_base_msat = default_config.forwarding_fee_base_msat;
        config.cltv_expiry_delta = u16::max_value();
        assert!(update_and_get_channel_update(&config, true, Some(&msg), true).is_some());
        expect_onion_failure("incorrect_cltv_expiry", UPDATE|13);

        // Reset the proportional fee and increase the CLTV expiry delta which should trigger a new
        // ChannelUpdate.
        config.cltv_expiry_delta = default_config.cltv_expiry_delta;
        config.forwarding_fee_proportional_millionths = u32::max_value();
        assert!(update_and_get_channel_update(&config, true, Some(&msg), true).is_some());
        expect_onion_failure("fee_insufficient", UPDATE|12);

        // To test persistence of the updated config, we'll re-initialize the ChannelManager.
        let config_after_restart = {
                let chan_1_monitor_serialized = get_monitor!(nodes[1], other_channel.3).encode();
                let chan_2_monitor_serialized = get_monitor!(nodes[1], channel_to_update.0).encode();
                reload_node!(nodes[1], *nodes[1].node.get_current_default_configuration(), &nodes[1].node.encode(),
                        &[&chan_1_monitor_serialized, &chan_2_monitor_serialized], persister, chain_monitor, channel_manager_1_deserialized);
                nodes[1].node.list_channels().iter()
                        .find(|channel| channel.channel_id == channel_to_update.0).unwrap()
                        .config.unwrap()
        };
        assert_eq!(config, config_after_restart);
}

#[test]
fn test_onion_failure_stale_channel_update() {
        do_test_onion_failure_stale_channel_update(false);
        do_test_onion_failure_stale_channel_update(true);
}

#[test]
fn test_always_create_tlv_format_onion_payloads() {
        // Verify that we always generate tlv onion format payloads, even if the features specifically
        // specifies no support for variable length onions, as the legacy payload format has been
        // deprecated in BOLT4.
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let mut node_cfgs = create_node_cfgs(3, &chanmon_cfgs);

        // Set `node[1]`'s init features to features which return `false` for
        // `supports_variable_length_onion()`
        let mut no_variable_length_onion_features = InitFeatures::empty();
        no_variable_length_onion_features.set_static_remote_key_required();
        *node_cfgs[1].override_init_features.borrow_mut() = Some(no_variable_length_onion_features);

        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1);
        create_announced_chan_between_nodes(&nodes, 1, 2);

        let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_bolt11_features(Bolt11InvoiceFeatures::empty()).unwrap();
        let (route, _payment_hash, _payment_preimage, _payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[2], payment_params, 40000);

        let hops = &route.paths[0].hops;
        // Asserts that the first hop to `node[1]` signals no support for variable length onions.
        assert!(!hops[0].node_features.supports_variable_length_onion());
        // Asserts that the first hop to `node[1]` signals no support for variable length onions.
        assert!(!hops[1].node_features.supports_variable_length_onion());

        let cur_height = nodes[0].best_block_info().1 + 1;
        let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
        let (onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
                &route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).unwrap();

        match onion_payloads[0] {
                msgs::OutboundOnionPayload::Forward {..} => {},
                _ => { panic!(
                        "Should have generated a `msgs::OnionHopDataFormat::NonFinalNode` payload for `hops[0]`,
                        despite that the features signals no support for variable length onions"
                )}
        }
        match onion_payloads[1] {
                msgs::OutboundOnionPayload::Receive {..} => {},
                _ => {panic!(
                        "Should have generated a `msgs::OnionHopDataFormat::FinalNode` payload for `hops[1]`,
                        despite that the features signals no support for variable length onions"
                )}
        }
}

#[test]
fn test_trampoline_onion_payload_serialization() {
        // As per https://github.com/lightning/bolts/blob/c01d2e6267d4a8d1095f0f1188970055a9a22d29/bolt04/trampoline-payment-onion-test.json#L3
        let trampoline_payload = OutboundTrampolinePayload::Forward {
                amt_to_forward: 100000000,
                outgoing_cltv_value: 800000,
                outgoing_node_id: PublicKey::from_slice(&<Vec<u8>>::from_hex("02edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145").unwrap()).unwrap(),
        };

        let slice_to_hex = |slice: &[u8]| {
                slice.iter()
                        .map(|b| format!("{:02x}", b).to_string())
                        .collect::<String>()
        };

        let carol_payload_hex = slice_to_hex(&trampoline_payload.encode());
        assert_eq!(carol_payload_hex, "2e020405f5e10004030c35000e2102edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145");
}

fn do_test_fail_htlc_backwards_with_reason(failure_code: FailureCode) {

        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 nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1);

        let payment_amount = 100_000;
        let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[1], payment_amount);
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);

        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        let mut payment_event = SendEvent::from_event(events.pop().unwrap());
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
        commitment_signed_dance!(nodes[1], nodes[0], payment_event.commitment_msg, false);

        expect_pending_htlcs_forwardable!(nodes[1]);
        expect_payment_claimable!(nodes[1], payment_hash, payment_secret, payment_amount);
        nodes[1].node.fail_htlc_backwards_with_reason(&payment_hash, failure_code);

        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash: payment_hash }]);
        check_added_monitors!(nodes[1], 1);

        let events = nodes[1].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 1);
        let (update_fail_htlc, commitment_signed) = match events[0] {
                MessageSendEvent::UpdateHTLCs { node_id: _ , updates: msgs::CommitmentUpdate { ref update_add_htlcs, ref update_fulfill_htlcs, ref update_fail_htlcs, ref update_fail_malformed_htlcs, ref update_fee, ref commitment_signed } } => {
                        assert!(update_add_htlcs.is_empty());
                        assert!(update_fulfill_htlcs.is_empty());
                        assert_eq!(update_fail_htlcs.len(), 1);
                        assert!(update_fail_malformed_htlcs.is_empty());
                        assert!(update_fee.is_none());
                        (update_fail_htlcs[0].clone(), commitment_signed)
                },
                _ => panic!("Unexpected event"),
        };

        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &update_fail_htlc);
        commitment_signed_dance!(nodes[0], nodes[1], commitment_signed, false, true);

        let failure_data = match failure_code {
                FailureCode::TemporaryNodeFailure => vec![],
                FailureCode::RequiredNodeFeatureMissing => vec![],
                FailureCode::IncorrectOrUnknownPaymentDetails => {
                        let mut htlc_msat_height_data = (payment_amount as u64).to_be_bytes().to_vec();
                        htlc_msat_height_data.extend_from_slice(&CHAN_CONFIRM_DEPTH.to_be_bytes());
                        htlc_msat_height_data
                },
                FailureCode::InvalidOnionPayload(data) => {
                        match data {
                                Some((typ, offset)) => [BigSize(typ).encode(), offset.encode()].concat(),
                                None => Vec::new(),
                        }
                }
        };

        let failure_code = failure_code.into();
        let permanent_flag = 0x4000;
        let permanent_fail = (failure_code & permanent_flag) != 0;
        expect_payment_failed!(nodes[0], payment_hash, permanent_fail, failure_code, failure_data);

}

#[test]
fn test_fail_htlc_backwards_with_reason() {
        do_test_fail_htlc_backwards_with_reason(FailureCode::TemporaryNodeFailure);
        do_test_fail_htlc_backwards_with_reason(FailureCode::RequiredNodeFeatureMissing);
        do_test_fail_htlc_backwards_with_reason(FailureCode::IncorrectOrUnknownPaymentDetails);
        do_test_fail_htlc_backwards_with_reason(FailureCode::InvalidOnionPayload(Some((1 << 16, 42))));
        do_test_fail_htlc_backwards_with_reason(FailureCode::InvalidOnionPayload(None));
}

macro_rules! get_phantom_route {
        ($nodes: expr, $amt: expr, $channel: expr) => {{
                let phantom_pubkey = $nodes[1].keys_manager.get_node_id(Recipient::PhantomNode).unwrap();
                let phantom_route_hint = $nodes[1].node.get_phantom_route_hints();
                let payment_params = PaymentParameters::from_node_id(phantom_pubkey, TEST_FINAL_CLTV)
                        .with_bolt11_features($nodes[1].node.bolt11_invoice_features()).unwrap()
                        .with_route_hints(vec![RouteHint(vec![
                                        RouteHintHop {
                                                src_node_id: $nodes[0].node.get_our_node_id(),
                                                short_channel_id: $channel.0.contents.short_channel_id,
                                                fees: RoutingFees {
                                                        base_msat: $channel.0.contents.fee_base_msat,
                                                        proportional_millionths: $channel.0.contents.fee_proportional_millionths,
                                                },
                                                cltv_expiry_delta: $channel.0.contents.cltv_expiry_delta,
                                                htlc_minimum_msat: None,
                                                htlc_maximum_msat: None,
                                        },
                                        RouteHintHop {
                                                src_node_id: phantom_route_hint.real_node_pubkey,
                                                short_channel_id: phantom_route_hint.phantom_scid,
                                                fees: RoutingFees {
                                                        base_msat: 0,
                                                        proportional_millionths: 0,
                                                },
                                                cltv_expiry_delta: MIN_CLTV_EXPIRY_DELTA,
                                                htlc_minimum_msat: None,
                                                htlc_maximum_msat: None,
                                        }
                ])]).unwrap();
                let scorer = test_utils::TestScorer::new();
                let network_graph = $nodes[0].network_graph.read_only();
                let route_params = RouteParameters::from_payment_params_and_value(payment_params, $amt);
                (get_route(
                        &$nodes[0].node.get_our_node_id(), &route_params, &network_graph,
                        Some(&$nodes[0].node.list_usable_channels().iter().collect::<Vec<_>>()),
                        $nodes[0].logger, &scorer, &Default::default(), &[0u8; 32]
                ).unwrap(), phantom_route_hint.phantom_scid)
        }
}}

#[test]
fn test_phantom_onion_hmac_failure() {
        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 nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route.
        let recv_value_msat = 10_000;
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(recv_value_msat));
        let (route, phantom_scid) = get_phantom_route!(nodes, recv_value_msat, channel);

        // Route the HTLC through to the destination.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        // Modify the payload so the phantom hop's HMAC is bogus.
        let sha256_of_onion = {
                let mut forward_htlcs = nodes[1].node.forward_htlcs.lock().unwrap();
                let mut pending_forward = forward_htlcs.get_mut(&phantom_scid).unwrap();
                match pending_forward[0] {
                        HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo {
                                forward_info: PendingHTLCInfo {
                                        routing: PendingHTLCRouting::Forward { ref mut onion_packet, .. },
                                        ..
                                }, ..
                        }) => {
                                onion_packet.hmac[onion_packet.hmac.len() - 1] ^= 1;
                                Sha256::hash(&onion_packet.hop_data).to_byte_array().to_vec()
                        },
                        _ => panic!("Unexpected forward"),
                }
        };
        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_pending_htlcs_forwardable_and_htlc_handling_failed_ignore!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash }]);
        nodes[1].node.process_pending_htlc_forwards();
        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        check_added_monitors!(&nodes[1], 1);
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(phantom_scid)
                .blamed_chan_closed(true)
                .expected_htlc_error_data(0x8000 | 0x4000 | 5, &sha256_of_onion);
        expect_payment_failed_conditions(&nodes[0], payment_hash, false, fail_conditions);
}

#[test]
fn test_phantom_invalid_onion_payload() {
        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 channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route.
        let recv_value_msat = 10_000;
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(recv_value_msat));
        let (route, phantom_scid) = get_phantom_route!(nodes, recv_value_msat, channel);

        // We'll use the session priv later when constructing an invalid onion packet.
        let session_priv = [3; 32];
        *nodes[0].keys_manager.override_random_bytes.lock().unwrap() = Some(session_priv);
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        // Modify the onion packet to have an invalid payment amount.
        for (_, pending_forwards) in nodes[1].node.forward_htlcs.lock().unwrap().iter_mut() {
                for f in pending_forwards.iter_mut() {
                        match f {
                                &mut HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo {
                                        forward_info: PendingHTLCInfo {
                                                routing: PendingHTLCRouting::Forward { ref mut onion_packet, .. },
                                                ..
                                        }, ..
                                }) => {
                                        // Construct the onion payloads for the entire route and an invalid amount.
                                        let height = nodes[0].best_block_info().1;
                                        let session_priv = SecretKey::from_slice(&session_priv).unwrap();
                                        let mut onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
                                        let recipient_onion_fields = RecipientOnionFields::secret_only(payment_secret);
                                        let (mut onion_payloads, _, _) = onion_utils::build_onion_payloads(
                                                &route.paths[0], msgs::MAX_VALUE_MSAT + 1,
                                                &recipient_onion_fields, height + 1, &None).unwrap();
                                        // We only want to construct the onion packet for the last hop, not the entire route, so
                                        // remove the first hop's payload and its keys.
                                        onion_keys.remove(0);
                                        onion_payloads.remove(0);

                                        let new_onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
                                        onion_packet.hop_data = new_onion_packet.hop_data;
                                        onion_packet.hmac = new_onion_packet.hmac;
                                },
                                _ => panic!("Unexpected forward"),
                        }
                }
        }
        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_pending_htlcs_forwardable_and_htlc_handling_failed_ignore!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash }]);
        nodes[1].node.process_pending_htlc_forwards();
        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        check_added_monitors!(&nodes[1], 1);
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let error_data = Vec::new();
        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(phantom_scid)
                .blamed_chan_closed(true)
                .expected_htlc_error_data(0x4000 | 22, &error_data);
        expect_payment_failed_conditions(&nodes[0], payment_hash, true, fail_conditions);
}

#[test]
fn test_phantom_final_incorrect_cltv_expiry() {
        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 nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route.
        let recv_value_msat = 10_000;
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(recv_value_msat));
        let (route, phantom_scid) = get_phantom_route!(nodes, recv_value_msat, channel);

        // Route the HTLC through to the destination.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        // Modify the payload so the phantom hop's HMAC is bogus.
        for (_, pending_forwards) in nodes[1].node.forward_htlcs.lock().unwrap().iter_mut() {
                for f in pending_forwards.iter_mut() {
                        match f {
                                &mut HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo {
                                        forward_info: PendingHTLCInfo { ref mut outgoing_cltv_value, .. }, ..
                                }) => {
                                        *outgoing_cltv_value -= 1;
                                },
                                _ => panic!("Unexpected forward"),
                        }
                }
        }
        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_pending_htlcs_forwardable_and_htlc_handling_failed_ignore!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash }]);
        nodes[1].node.process_pending_htlc_forwards();
        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        check_added_monitors!(&nodes[1], 1);
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let expected_cltv: u32 = 80;
        let error_data = expected_cltv.to_be_bytes().to_vec();
        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(phantom_scid)
                .expected_htlc_error_data(18, &error_data);
        expect_payment_failed_conditions(&nodes[0], payment_hash, false, fail_conditions);
}

#[test]
fn test_phantom_failure_too_low_cltv() {
        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 nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route.
        let recv_value_msat = 10_000;
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(recv_value_msat));
        let (mut route, phantom_scid) = get_phantom_route!(nodes, recv_value_msat, channel);

        // Modify the route to have a too-low cltv.
        route.paths[0].hops[1].cltv_expiry_delta = 5;

        // Route the HTLC through to the destination.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_pending_htlcs_forwardable_and_htlc_handling_failed_ignore!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash }]);
        nodes[1].node.process_pending_htlc_forwards();
        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        check_added_monitors!(&nodes[1], 1);
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let mut error_data = recv_value_msat.to_be_bytes().to_vec();
        error_data.extend_from_slice(
                &nodes[0].node.best_block.read().unwrap().height.to_be_bytes(),
        );
        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(phantom_scid)
                .expected_htlc_error_data(0x4000 | 15, &error_data);
        expect_payment_failed_conditions(&nodes[0], payment_hash, true, fail_conditions);
}

#[test]
fn test_phantom_failure_modified_cltv() {
        // Test that we fail back phantoms if the upstream node fiddled with the CLTV too much with the
        // correct error code.
        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 nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route.
        let recv_value_msat = 10_000;
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(recv_value_msat));
        let (mut route, phantom_scid) = get_phantom_route!(nodes, recv_value_msat, channel);

        // Route the HTLC through to the destination.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        // Modify the route to have a too-low cltv.
        update_add.cltv_expiry -= 10;

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(phantom_scid)
                .expected_htlc_error_data(0x2000 | 2, &[]);
        expect_payment_failed_conditions(&nodes[0], payment_hash, false, fail_conditions);
}

#[test]
fn test_phantom_failure_expires_too_soon() {
        // Test that we fail back phantoms if the HTLC got delayed and we got blocks in between with
        // the correct error code.
        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 nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route.
        let recv_value_msat = 10_000;
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(recv_value_msat));
        let (mut route, phantom_scid) = get_phantom_route!(nodes, recv_value_msat, channel);

        // Route the HTLC through to the destination.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        connect_blocks(&nodes[1], CLTV_FAR_FAR_AWAY);
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(phantom_scid)
                .expected_htlc_error_data(0x2000 | 2, &[]);
        expect_payment_failed_conditions(&nodes[0], payment_hash, false, fail_conditions);
}

#[test]
fn test_phantom_failure_too_low_recv_amt() {
        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 nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route with a too-low amount.
        let recv_amt_msat = 10_000;
        let bad_recv_amt_msat = recv_amt_msat - 10;
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(recv_amt_msat));
        let (mut route, phantom_scid) = get_phantom_route!(nodes, bad_recv_amt_msat, channel);

        // Route the HTLC through to the destination.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_pending_htlcs_forwardable_and_htlc_handling_failed_ignore!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash: payment_hash.clone() }]);
        nodes[1].node.process_pending_htlc_forwards();
        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        check_added_monitors!(&nodes[1], 1);
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let mut error_data = bad_recv_amt_msat.to_be_bytes().to_vec();
        error_data.extend_from_slice(&nodes[1].node.best_block.read().unwrap().height.to_be_bytes());
        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(phantom_scid)
                .expected_htlc_error_data(0x4000 | 15, &error_data);
        expect_payment_failed_conditions(&nodes[0], payment_hash, true, fail_conditions);
}

#[test]
fn test_phantom_dust_exposure_failure() {
        do_test_phantom_dust_exposure_failure(false);
        do_test_phantom_dust_exposure_failure(true);
}

fn do_test_phantom_dust_exposure_failure(multiplier_dust_limit: bool) {
        // Set the max dust exposure to the dust limit.
        let max_dust_exposure = 546;
        let mut receiver_config = UserConfig::default();
        // Default test fee estimator rate is 253, so to set the max dust exposure to the dust limit,
        // we need to set the multiplier to 2.
        receiver_config.channel_config.max_dust_htlc_exposure =
                if multiplier_dust_limit { MaxDustHTLCExposure::FeeRateMultiplier(2) }
                else { MaxDustHTLCExposure::FixedLimitMsat(max_dust_exposure) };
        receiver_config.channel_handshake_config.announced_channel = true;

        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, Some(receiver_config)]);
        let nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route with an amount exceeding the dust exposure threshold of nodes[1].
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(max_dust_exposure + 1));
        let (mut route, _) = get_phantom_route!(nodes, max_dust_exposure + 1, channel);

        // Route the HTLC through to the destination.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let mut err_data = Vec::new();
        err_data.extend_from_slice(&(channel.1.serialized_length() as u16 + 2).to_be_bytes());
        err_data.extend_from_slice(&ChannelUpdate::TYPE.to_be_bytes());
        err_data.extend_from_slice(&channel.1.encode());

        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(route.paths[0].hops.last().as_ref().unwrap().short_channel_id)
                .blamed_chan_closed(false)
                .expected_htlc_error_data(0x1000 | 7, &err_data);
        expect_payment_failed_conditions(&nodes[0], payment_hash, false, fail_conditions);
}

#[test]
fn test_phantom_failure_reject_payment() {
        // Test that the user can successfully fail back a phantom node payment.
        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 nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let channel = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Get the route with a too-low amount.
        let recv_amt_msat = 10_000;
        let (_, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1], Some(recv_amt_msat));
        let (mut route, phantom_scid) = get_phantom_route!(nodes, recv_amt_msat, channel);

        // Route the HTLC through to the destination.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let mut update_add = update_0.update_add_htlcs[0].clone();

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);

        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_payment_claimable!(nodes[1], payment_hash, payment_secret, recv_amt_msat, None, route.paths[0].hops.last().unwrap().pubkey);
        nodes[1].node.fail_htlc_backwards(&payment_hash);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed_ignore!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash }]);
        nodes[1].node.process_pending_htlc_forwards();

        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        check_added_monitors!(&nodes[1], 1);
        assert!(update_1.update_fail_htlcs.len() == 1);
        let fail_msg = update_1.update_fail_htlcs[0].clone();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

        // Ensure the payment fails with the expected error.
        let mut error_data = recv_amt_msat.to_be_bytes().to_vec();
        error_data.extend_from_slice(&nodes[1].node.best_block.read().unwrap().height.to_be_bytes());
        let mut fail_conditions = PaymentFailedConditions::new()
                .blamed_scid(phantom_scid)
                .expected_htlc_error_data(0x4000 | 15, &error_data);
        expect_payment_failed_conditions(&nodes[0], payment_hash, true, fail_conditions);
}