Merge pull request #2954 from TheBlueMatt/2024-03-test-ci-beta-fail
[rust-lightning] / lightning / src / ln / onion_utils.rs
index 137699521f482b6b186a4375477284a010bc897b..f2b5c69e9e677fb10e3886e4240b58bacd66395a 100644 (file)
@@ -7,33 +7,34 @@
 // You may not use this file except in accordance with one or both of these
 // licenses.
 
-use crate::ln::{PaymentHash, PaymentPreimage};
+use crate::crypto::chacha20::ChaCha20;
+use crate::crypto::streams::ChaChaReader;
 use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields};
 use crate::ln::msgs;
 use crate::ln::wire::Encode;
+use crate::ln::{PaymentHash, PaymentPreimage};
 use crate::routing::gossip::NetworkUpdate;
 use crate::routing::router::{BlindedTail, Path, RouteHop};
 use crate::sign::NodeSigner;
-use crate::util::chacha20::{ChaCha20, ChaChaReader};
 use crate::util::errors::{self, APIError};
-use crate::util::ser::{Readable, ReadableArgs, Writeable, Writer, LengthCalculatingWriter};
 use crate::util::logger::Logger;
+use crate::util::ser::{LengthCalculatingWriter, Readable, ReadableArgs, Writeable, Writer};
 
-use bitcoin::hashes::{Hash, HashEngine};
 use bitcoin::hashes::cmp::fixed_time_eq;
 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
 use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::hashes::{Hash, HashEngine};
 
-use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar};
-use bitcoin::secp256k1::Secp256k1;
-use bitcoin::secp256k1::ecdh::SharedSecret;
 use bitcoin::secp256k1;
+use bitcoin::secp256k1::ecdh::SharedSecret;
+use bitcoin::secp256k1::{PublicKey, Scalar, Secp256k1, SecretKey};
 
-use crate::prelude::*;
 use crate::io::{Cursor, Read};
-use core::convert::{AsMut, TryInto};
 use core::ops::Deref;
 
+#[allow(unused_imports)]
+use crate::prelude::*;
+
 pub(crate) struct OnionKeys {
        #[cfg(test)]
        pub(crate) shared_secret: SharedSecret,
@@ -55,16 +56,15 @@ pub(crate) fn gen_rho_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
 #[inline]
 pub(crate) fn gen_rho_mu_from_shared_secret(shared_secret: &[u8]) -> ([u8; 32], [u8; 32]) {
        assert_eq!(shared_secret.len(), 32);
-       ({
-               let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
-               hmac.input(&shared_secret);
-               Hmac::from_engine(hmac).to_byte_array()
-       },
-       {
-               let mut hmac = HmacEngine::<Sha256>::new(&[0x6d, 0x75]); // mu
-               hmac.input(&shared_secret);
-               Hmac::from_engine(hmac).to_byte_array()
-       })
+       let mut engine_rho = HmacEngine::<Sha256>::new(b"rho");
+       engine_rho.input(&shared_secret);
+       let hmac_rho = Hmac::from_engine(engine_rho).to_byte_array();
+
+       let mut engine_mu = HmacEngine::<Sha256>::new(b"mu");
+       engine_mu.input(&shared_secret);
+       let hmac_mu = Hmac::from_engine(engine_mu).to_byte_array();
+
+       (hmac_rho, hmac_mu)
 }
 
 #[inline]
@@ -94,7 +94,7 @@ pub(super) fn gen_pad_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
 
 /// Calculates a pubkey for the next hop, such as the next hop's packet pubkey or blinding point.
 pub(crate) fn next_hop_pubkey<T: secp256k1::Verification>(
-       secp_ctx: &Secp256k1<T>, curr_pubkey: PublicKey, shared_secret: &[u8]
+       secp_ctx: &Secp256k1<T>, curr_pubkey: PublicKey, shared_secret: &[u8],
 ) -> Result<PublicKey, secp256k1::Error> {
        let blinding_factor = {
                let mut sha = Sha256::engine();
@@ -109,18 +109,21 @@ pub(crate) fn next_hop_pubkey<T: secp256k1::Verification>(
 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 #[inline]
 pub(super) fn construct_onion_keys_callback<T, FType>(
-       secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, mut callback: FType
+       secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, mut callback: FType,
 ) -> Result<(), secp256k1::Error>
 where
        T: secp256k1::Signing,
-       FType: FnMut(SharedSecret, [u8; 32], PublicKey, Option<&RouteHop>, usize)
+       FType: FnMut(SharedSecret, [u8; 32], PublicKey, Option<&RouteHop>, usize),
 {
        let mut blinded_priv = session_priv.clone();
        let mut blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 
        let unblinded_hops_iter = path.hops.iter().map(|h| (&h.pubkey, Some(h)));
-       let blinded_pks_iter = path.blinded_tail.as_ref()
-               .map(|t| t.hops.iter()).unwrap_or([].iter())
+       let blinded_pks_iter = path
+               .blinded_tail
+               .as_ref()
+               .map(|t| t.hops.iter())
+               .unwrap_or([].iter())
                .skip(1) // Skip the intro node because it's included in the unblinded hops
                .map(|h| (&h.blinded_node_id, None));
        for (idx, (pubkey, route_hop_opt)) in unblinded_hops_iter.chain(blinded_pks_iter).enumerate() {
@@ -143,35 +146,43 @@ where
 }
 
 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
-pub(super) fn construct_onion_keys<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey) -> Result<Vec<OnionKeys>, secp256k1::Error> {
+pub(super) fn construct_onion_keys<T: secp256k1::Signing>(
+       secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey,
+) -> Result<Vec<OnionKeys>, secp256k1::Error> {
        let mut res = Vec::with_capacity(path.hops.len());
 
-       construct_onion_keys_callback(secp_ctx, &path, session_priv,
-               |shared_secret, _blinding_factor, ephemeral_pubkey, _, _|
-       {
-               let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());
+       construct_onion_keys_callback(
+               secp_ctx,
+               &path,
+               session_priv,
+               |shared_secret, _blinding_factor, ephemeral_pubkey, _, _| {
+                       let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());
 
-               res.push(OnionKeys {
-                       #[cfg(test)]
-                       shared_secret,
-                       #[cfg(test)]
-                       blinding_factor: _blinding_factor,
-                       ephemeral_pubkey,
-                       rho,
-                       mu,
-               });
-       })?;
+                       res.push(OnionKeys {
+                               #[cfg(test)]
+                               shared_secret,
+                               #[cfg(test)]
+                               blinding_factor: _blinding_factor,
+                               ephemeral_pubkey,
+                               rho,
+                               mu,
+                       });
+               },
+       )?;
 
        Ok(res)
 }
 
 /// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
-pub(super) fn build_onion_payloads(path: &Path, total_msat: u64, mut recipient_onion: RecipientOnionFields, starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>) -> Result<(Vec<msgs::OutboundOnionPayload>, u64, u32), APIError> {
+pub(super) fn build_onion_payloads(
+       path: &Path, total_msat: u64, mut recipient_onion: RecipientOnionFields,
+       starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>,
+) -> Result<(Vec<msgs::OutboundOnionPayload>, u64, u32), APIError> {
        let mut cur_value_msat = 0u64;
        let mut cur_cltv = starting_htlc_offset;
        let mut last_short_channel_id = 0;
        let mut res: Vec<msgs::OutboundOnionPayload> = Vec::with_capacity(
-               path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len())
+               path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len()),
        );
 
        for (idx, hop) in path.hops.iter().rev().enumerate() {
@@ -179,11 +190,20 @@ pub(super) fn build_onion_payloads(path: &Path, total_msat: u64, mut recipient_o
                // exactly as it should be (and the next hop isn't trying to probe to find out if we're
                // the intended recipient).
                let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
-               let cltv = if cur_cltv == starting_htlc_offset { hop.cltv_expiry_delta + starting_htlc_offset } else { cur_cltv };
+               let cltv = if cur_cltv == starting_htlc_offset {
+                       hop.cltv_expiry_delta + starting_htlc_offset
+               } else {
+                       cur_cltv
+               };
                if idx == 0 {
                        if let Some(BlindedTail {
-                               blinding_point, hops, final_value_msat, excess_final_cltv_expiry_delta, ..
-                       }) = &path.blinded_tail {
+                               blinding_point,
+                               hops,
+                               final_value_msat,
+                               excess_final_cltv_expiry_delta,
+                               ..
+                       }) = &path.blinded_tail
+                       {
                                let mut blinding_point = Some(*blinding_point);
                                for (i, blinded_hop) in hops.iter().enumerate() {
                                        if i == hops.len() - 1 {
@@ -194,6 +214,8 @@ pub(super) fn build_onion_payloads(path: &Path, total_msat: u64, mut recipient_o
                                                        cltv_expiry_height: cur_cltv + excess_final_cltv_expiry_delta,
                                                        encrypted_tlvs: blinded_hop.encrypted_payload.clone(),
                                                        intro_node_blinding_point: blinding_point.take(),
+                                                       keysend_preimage: *keysend_preimage,
+                                                       custom_tlvs: recipient_onion.custom_tlvs.clone(),
                                                });
                                        } else {
                                                res.push(msgs::OutboundOnionPayload::BlindedForward {
@@ -205,11 +227,10 @@ pub(super) fn build_onion_payloads(path: &Path, total_msat: u64, mut recipient_o
                        } else {
                                res.push(msgs::OutboundOnionPayload::Receive {
                                        payment_data: if let Some(secret) = recipient_onion.payment_secret.take() {
-                                               Some(msgs::FinalOnionHopData {
-                                                       payment_secret: secret,
-                                                       total_msat,
-                                               })
-                                       } else { None },
+                                               Some(msgs::FinalOnionHopData { payment_secret: secret, total_msat })
+                                       } else {
+                                               None
+                                       },
                                        payment_metadata: recipient_onion.payment_metadata.take(),
                                        keysend_preimage: *keysend_preimage,
                                        custom_tlvs: recipient_onion.custom_tlvs.clone(),
@@ -218,19 +239,20 @@ pub(super) fn build_onion_payloads(path: &Path, total_msat: u64, mut recipient_o
                                });
                        }
                } else {
-                       res.insert(0, msgs::OutboundOnionPayload::Forward {
+                       let payload = msgs::OutboundOnionPayload::Forward {
                                short_channel_id: last_short_channel_id,
                                amt_to_forward: value_msat,
                                outgoing_cltv_value: cltv,
-                       });
+                       };
+                       res.insert(0, payload);
                }
                cur_value_msat += hop.fee_msat;
                if cur_value_msat >= 21000000 * 100000000 * 1000 {
-                       return Err(APIError::InvalidRoute{err: "Channel fees overflowed?".to_owned()});
+                       return Err(APIError::InvalidRoute { err: "Channel fees overflowed?".to_owned() });
                }
                cur_cltv += hop.cltv_expiry_delta as u32;
                if cur_cltv >= 500000000 {
-                       return Err(APIError::InvalidRoute{err: "Channel CLTV overflowed?".to_owned()});
+                       return Err(APIError::InvalidRoute { err: "Channel CLTV overflowed?".to_owned() });
                }
                last_short_channel_id = hop.short_channel_id;
        }
@@ -239,14 +261,14 @@ pub(super) fn build_onion_payloads(path: &Path, total_msat: u64, mut recipient_o
 
 /// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now
 /// the hops can be of variable length.
-pub(crate) const ONION_DATA_LEN: usize = 20*65;
+pub(crate) const ONION_DATA_LEN: usize = 20 * 65;
 
 pub(super) const INVALID_ONION_BLINDING: u16 = 0x8000 | 0x4000 | 24;
 
 #[inline]
 fn shift_slice_right(arr: &mut [u8], amt: usize) {
        for i in (amt..arr.len()).rev() {
-               arr[i] = arr[i-amt];
+               arr[i] = arr[i - amt];
        }
        for i in 0..amt {
                arr[i] = 0;
@@ -255,28 +277,59 @@ fn shift_slice_right(arr: &mut [u8], amt: usize) {
 
 pub(super) fn construct_onion_packet(
        payloads: Vec<msgs::OutboundOnionPayload>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
-       associated_data: &PaymentHash
+       associated_data: &PaymentHash,
 ) -> Result<msgs::OnionPacket, ()> {
        let mut packet_data = [0; ONION_DATA_LEN];
 
        let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
        chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 
+       let packet = FixedSizeOnionPacket(packet_data);
        construct_onion_packet_with_init_noise::<_, _>(
-               payloads, onion_keys, FixedSizeOnionPacket(packet_data), Some(associated_data))
+               payloads,
+               onion_keys,
+               packet,
+               Some(associated_data),
+       )
+}
+
+#[allow(unused)]
+pub(super) fn construct_trampoline_onion_packet(
+       payloads: Vec<msgs::OutboundTrampolinePayload>, onion_keys: Vec<OnionKeys>,
+       prng_seed: [u8; 32], associated_data: &PaymentHash, length: u16,
+) -> Result<msgs::TrampolineOnionPacket, ()> {
+       let mut packet_data = vec![0u8; length as usize];
+
+       let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
+       chacha.process(&vec![0u8; length as usize], &mut packet_data);
+
+       construct_onion_packet_with_init_noise::<_, _>(
+               payloads,
+               onion_keys,
+               packet_data,
+               Some(associated_data),
+       )
 }
 
 #[cfg(test)]
 /// Used in testing to write bogus `BogusOnionHopData` as well as `RawOnionHopData`, which is
 /// otherwise not representable in `msgs::OnionHopData`.
-pub(super) fn construct_onion_packet_with_writable_hopdata<HD: Writeable>(payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], associated_data: &PaymentHash) -> Result<msgs::OnionPacket, ()> {
+pub(super) fn construct_onion_packet_with_writable_hopdata<HD: Writeable>(
+       payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
+       associated_data: &PaymentHash,
+) -> Result<msgs::OnionPacket, ()> {
        let mut packet_data = [0; ONION_DATA_LEN];
 
        let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
        chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 
+       let packet = FixedSizeOnionPacket(packet_data);
        construct_onion_packet_with_init_noise::<_, _>(
-               payloads, onion_keys, FixedSizeOnionPacket(packet_data), Some(associated_data))
+               payloads,
+               onion_keys,
+               packet,
+               Some(associated_data),
+       )
 }
 
 /// Since onion message packets and onion payment packets have different lengths but are otherwise
@@ -302,8 +355,8 @@ pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> u
 }
 
 pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
-       payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize) -> Result<P, ()>
-{
+       payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize,
+) -> Result<P, ()> {
        let mut packet_data = vec![0; packet_data_len];
 
        let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
@@ -313,8 +366,9 @@ pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec
 }
 
 fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
-       mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data, associated_data: Option<&PaymentHash>) -> Result<P, ()>
-{
+       mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data,
+       associated_data: Option<&PaymentHash>,
+) -> Result<P, ()> {
        let filler = {
                let packet_data = packet_data.as_mut();
                const ONION_HOP_DATA_LEN: usize = 65; // We may decrease this eventually after TLV is common
@@ -323,7 +377,8 @@ fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
                let mut pos = 0;
                for (i, (payload, keys)) in payloads.iter().zip(onion_keys.iter()).enumerate() {
                        let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
-                       for _ in 0..(packet_data.len() - pos) { // TODO: Batch this.
+                       // TODO: Batch this.
+                       for _ in 0..(packet_data.len() - pos) {
                                let mut dummy = [0; 1];
                                chacha.process_in_place(&mut dummy); // We don't have a seek function :(
                        }
@@ -335,7 +390,9 @@ fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
                                return Err(());
                        }
 
-                       if i == payloads.len() - 1 { break; }
+                       if i == payloads.len() - 1 {
+                               break;
+                       }
 
                        res.resize(pos, 0u8);
                        chacha.process_in_place(&mut res);
@@ -375,19 +432,21 @@ fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
 
 /// Encrypts a failure packet. raw_packet can either be a
 /// msgs::DecodedOnionErrorPacket.encode() result or a msgs::OnionErrorPacket.data element.
-pub(super) fn encrypt_failure_packet(shared_secret: &[u8], raw_packet: &[u8]) -> msgs::OnionErrorPacket {
+pub(super) fn encrypt_failure_packet(
+       shared_secret: &[u8], raw_packet: &[u8],
+) -> msgs::OnionErrorPacket {
        let ammag = gen_ammag_from_shared_secret(&shared_secret);
 
        let mut packet_crypted = Vec::with_capacity(raw_packet.len());
        packet_crypted.resize(raw_packet.len(), 0);
        let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
        chacha.process(&raw_packet, &mut packet_crypted[..]);
-       msgs::OnionErrorPacket {
-               data: packet_crypted,
-       }
+       msgs::OnionErrorPacket { data: packet_crypted }
 }
 
-pub(super) fn build_failure_packet(shared_secret: &[u8], failure_type: u16, failure_data: &[u8]) -> msgs::DecodedOnionErrorPacket {
+pub(super) fn build_failure_packet(
+       shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
+) -> msgs::DecodedOnionErrorPacket {
        assert_eq!(shared_secret.len(), 32);
        assert!(failure_data.len() <= 256 - 2);
 
@@ -405,11 +464,7 @@ pub(super) fn build_failure_packet(shared_secret: &[u8], failure_type: u16, fail
                res.resize(256 - 2 - failure_data.len(), 0);
                res
        };
-       let mut packet = msgs::DecodedOnionErrorPacket {
-               hmac: [0; 32],
-               failuremsg,
-               pad,
-       };
+       let mut packet = msgs::DecodedOnionErrorPacket { hmac: [0; 32], failuremsg, pad };
 
        let mut hmac = HmacEngine::<Sha256>::new(&um);
        hmac.input(&packet.encode()[32..]);
@@ -419,7 +474,9 @@ pub(super) fn build_failure_packet(shared_secret: &[u8], failure_type: u16, fail
 }
 
 #[cfg(test)]
-pub(super) fn build_first_hop_failure_packet(shared_secret: &[u8], failure_type: u16, failure_data: &[u8]) -> msgs::OnionErrorPacket {
+pub(super) fn build_first_hop_failure_packet(
+       shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
+) -> msgs::OnionErrorPacket {
        let failure_packet = build_failure_packet(shared_secret, failure_type, failure_data);
        encrypt_failure_packet(shared_secret, &failure_packet.encode()[..])
 }
@@ -428,6 +485,7 @@ pub(crate) struct DecodedOnionFailure {
        pub(crate) network_update: Option<NetworkUpdate>,
        pub(crate) short_channel_id: Option<u64>,
        pub(crate) payment_failed_permanently: bool,
+       pub(crate) failed_within_blinded_path: bool,
        #[cfg(test)]
        pub(crate) onion_error_code: Option<u16>,
        #[cfg(test)]
@@ -437,7 +495,7 @@ pub(crate) struct DecodedOnionFailure {
 /// Note that we always decrypt `packet` in-place here even if the deserialization into
 /// [`msgs::DecodedOnionErrorPacket`] ultimately fails.
 fn decrypt_onion_error_packet(
-       packet: &mut Vec<u8>, shared_secret: SharedSecret
+       packet: &mut Vec<u8>, shared_secret: SharedSecret,
 ) -> Result<msgs::DecodedOnionErrorPacket, msgs::DecodeError> {
        let ammag = gen_ammag_from_shared_secret(shared_secret.as_ref());
        let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
@@ -449,19 +507,26 @@ fn decrypt_onion_error_packet(
 /// OutboundRoute).
 #[inline]
 pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
-       secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut encrypted_packet: Vec<u8>
-) -> DecodedOnionFailure where L::Target: Logger {
-       let (path, session_priv, first_hop_htlc_msat) = if let &HTLCSource::OutboundRoute {
-               ref path, ref session_priv, ref first_hop_htlc_msat, ..
-       } = htlc_source {
-               (path, session_priv, first_hop_htlc_msat)
-       } else { unreachable!() };
+       secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut encrypted_packet: Vec<u8>,
+) -> DecodedOnionFailure
+where
+       L::Target: Logger,
+{
+       let (path, session_priv, first_hop_htlc_msat) = match htlc_source {
+               HTLCSource::OutboundRoute {
+                       ref path, ref session_priv, ref first_hop_htlc_msat, ..
+               } => (path, session_priv, first_hop_htlc_msat),
+               _ => {
+                       unreachable!()
+               },
+       };
 
        // Learnings from the HTLC failure to inform future payment retries and scoring.
        struct FailureLearnings {
                network_update: Option<NetworkUpdate>,
                short_channel_id: Option<u64>,
                payment_failed_permanently: bool,
+               failed_within_blinded_path: bool,
        }
        let mut res: Option<FailureLearnings> = None;
        let mut htlc_msat = *first_hop_htlc_msat;
@@ -475,10 +540,10 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
        const UPDATE: u16 = 0x1000;
 
        // Handle packed channel/node updates for passing back for the route handler
-       construct_onion_keys_callback(secp_ctx, &path, session_priv,
-               |shared_secret, _, _, route_hop_opt, route_hop_idx|
-       {
-               if res.is_some() { return; }
+       let callback = |shared_secret, _, _, route_hop_opt: Option<&RouteHop>, route_hop_idx| {
+               if res.is_some() {
+                       return;
+               }
 
                let route_hop = match route_hop_opt {
                        Some(hop) => hop,
@@ -487,9 +552,12 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                                error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
                                error_packet_ret = Some(vec![0; 32]);
                                res = Some(FailureLearnings {
-                                       network_update: None, short_channel_id: None, payment_failed_permanently: false
+                                       network_update: None,
+                                       short_channel_id: None,
+                                       payment_failed_permanently: false,
+                                       failed_within_blinded_path: true,
                                });
-                               return
+                               return;
                        },
                };
 
@@ -498,31 +566,39 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                let num_blinded_hops = path.blinded_tail.as_ref().map_or(0, |bt| bt.hops.len());
                // For 1-hop blinded paths, the final `path.hops` entry is the recipient.
                is_from_final_node = route_hop_idx + 1 == path.hops.len() && num_blinded_hops <= 1;
-               let failing_route_hop = if is_from_final_node { route_hop } else {
+               let failing_route_hop = if is_from_final_node {
+                       route_hop
+               } else {
                        match path.hops.get(route_hop_idx + 1) {
                                Some(hop) => hop,
                                None => {
                                        // The failing hop is within a multi-hop blinded path.
-                                       #[cfg(not(test))] {
+                                       #[cfg(not(test))]
+                                       {
                                                error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
                                                error_packet_ret = Some(vec![0; 32]);
                                        }
-                                       #[cfg(test)] {
+                                       #[cfg(test)]
+                                       {
                                                // Actually parse the onion error data in tests so we can check that blinded hops fail
                                                // back correctly.
-                                               let err_packet = decrypt_onion_error_packet(
-                                                       &mut encrypted_packet, shared_secret
-                                               ).unwrap();
-                                               error_code_ret =
-                                                       Some(u16::from_be_bytes(err_packet.failuremsg.get(0..2).unwrap().try_into().unwrap()));
+                                               let err_packet =
+                                                       decrypt_onion_error_packet(&mut encrypted_packet, shared_secret)
+                                                               .unwrap();
+                                               error_code_ret = Some(u16::from_be_bytes(
+                                                       err_packet.failuremsg.get(0..2).unwrap().try_into().unwrap(),
+                                               ));
                                                error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
                                        }
 
                                        res = Some(FailureLearnings {
-                                               network_update: None, short_channel_id: None, payment_failed_permanently: false
+                                               network_update: None,
+                                               short_channel_id: None,
+                                               payment_failed_permanently: false,
+                                               failed_within_blinded_path: true,
                                        });
-                                       return
-                               }
+                                       return;
+                               },
                        }
                };
 
@@ -531,13 +607,15 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 
                let err_packet = match decrypt_onion_error_packet(&mut encrypted_packet, shared_secret) {
                        Ok(p) => p,
-                       Err(_) => return
+                       Err(_) => return,
                };
                let um = gen_um_from_shared_secret(shared_secret.as_ref());
                let mut hmac = HmacEngine::<Sha256>::new(&um);
                hmac.input(&err_packet.encode()[32..]);
 
-               if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &err_packet.hmac) { return }
+               if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &err_packet.hmac) {
+                       return;
+               }
                let error_code_slice = match err_packet.failuremsg.get(0..2) {
                        Some(s) => s,
                        None => {
@@ -549,10 +627,13 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                                });
                                let short_channel_id = Some(route_hop.short_channel_id);
                                res = Some(FailureLearnings {
-                                       network_update, short_channel_id, payment_failed_permanently: is_from_final_node
+                                       network_update,
+                                       short_channel_id,
+                                       payment_failed_permanently: is_from_final_node,
+                                       failed_within_blinded_path: false,
                                });
-                               return
-                       }
+                               return;
+                       },
                };
 
                let error_code = u16::from_be_bytes(error_code_slice.try_into().expect("len is 2"));
@@ -563,7 +644,7 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 
                // indicate that payment parameter has failed and no need to update Route object
                let payment_failed = match error_code & 0xff {
-                       15|16|17|18|19|23 => true,
+                       15 | 16 | 17 | 18 | 19 | 23 => true,
                        _ => false,
                } && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes
 
@@ -584,7 +665,8 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                        });
                } else if error_code & NODE == NODE {
                        let is_permanent = error_code & PERM == PERM;
-                       network_update = Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
+                       network_update =
+                               Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
                        short_channel_id = Some(route_hop.short_channel_id);
                } else if error_code & PERM == PERM {
                        if !payment_failed {
@@ -595,9 +677,15 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                                short_channel_id = Some(failing_route_hop.short_channel_id);
                        }
                } else if error_code & UPDATE == UPDATE {
-                       if let Some(update_len_slice) = err_packet.failuremsg.get(debug_field_size+2..debug_field_size+4) {
-                               let update_len = u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
-                               if let Some(mut update_slice) = err_packet.failuremsg.get(debug_field_size + 4..debug_field_size + 4 + update_len) {
+                       if let Some(update_len_slice) =
+                               err_packet.failuremsg.get(debug_field_size + 2..debug_field_size + 4)
+                       {
+                               let update_len =
+                                       u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
+                               if let Some(mut update_slice) = err_packet
+                                       .failuremsg
+                                       .get(debug_field_size + 4..debug_field_size + 4 + update_len)
+                               {
                                        // Historically, the BOLTs were unclear if the message type
                                        // bytes should be included here or not. The BOLTs have now
                                        // been updated to indicate that they *are* included, but many
@@ -607,7 +695,9 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                                        // permissiveness introduces the (although small) possibility
                                        // that we fail to decode legitimate channel updates that
                                        // happen to start with ChannelUpdate::TYPE, i.e., [0x01, 0x02].
-                                       if update_slice.len() > 2 && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes() {
+                                       if update_slice.len() > 2
+                                               && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes()
+                                       {
                                                update_slice = &update_slice[2..];
                                        } else {
                                                log_trace!(logger, "Failure provided features a channel update without type prefix. Deprecated, but allowing for now.");
@@ -618,20 +708,36 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                                                // MAY treat the channel_update as invalid.
                                                let is_chan_update_invalid = match error_code & 0xff {
                                                        7 => false,
-                                                       11 => update_opt.is_ok() &&
-                                                               amt_to_forward >
-                                                                       update_opt.as_ref().unwrap().contents.htlc_minimum_msat,
-                                                       12 => update_opt.is_ok() && amt_to_forward
-                                                               .checked_mul(update_opt.as_ref().unwrap()
-                                                                       .contents.fee_proportional_millionths as u64)
-                                                               .map(|prop_fee| prop_fee / 1_000_000)
-                                                               .and_then(|prop_fee| prop_fee.checked_add(
-                                                                       update_opt.as_ref().unwrap().contents.fee_base_msat as u64))
-                                                               .map(|fee_msats| route_hop.fee_msat >= fee_msats)
-                                                               .unwrap_or(false),
-                                                       13 => update_opt.is_ok() &&
-                                                               route_hop.cltv_expiry_delta as u16 >=
-                                                                       update_opt.as_ref().unwrap().contents.cltv_expiry_delta,
+                                                       11 => {
+                                                               update_opt.is_ok()
+                                                                       && amt_to_forward
+                                                                               > update_opt.as_ref().unwrap().contents.htlc_minimum_msat
+                                                       },
+                                                       12 => {
+                                                               update_opt.is_ok()
+                                                                       && amt_to_forward
+                                                                               .checked_mul(
+                                                                                       update_opt
+                                                                                               .as_ref()
+                                                                                               .unwrap()
+                                                                                               .contents
+                                                                                               .fee_proportional_millionths as u64,
+                                                                               )
+                                                                               .map(|prop_fee| prop_fee / 1_000_000)
+                                                                               .and_then(|prop_fee| {
+                                                                                       prop_fee.checked_add(
+                                                                                               update_opt.as_ref().unwrap().contents.fee_base_msat
+                                                                                                       as u64,
+                                                                                       )
+                                                                               })
+                                                                               .map(|fee_msats| route_hop.fee_msat >= fee_msats)
+                                                                               .unwrap_or(false)
+                                                       },
+                                                       13 => {
+                                                               update_opt.is_ok()
+                                                                       && route_hop.cltv_expiry_delta as u16
+                                                                               >= update_opt.as_ref().unwrap().contents.cltv_expiry_delta
+                                                       },
                                                        14 => false, // expiry_too_soon; always valid?
                                                        20 => update_opt.as_ref().unwrap().contents.flags & 2 == 0,
                                                        _ => false, // unknown error code; take channel_update as valid
@@ -647,14 +753,15 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                                                        if let Ok(chan_update) = update_opt {
                                                                // Make sure the ChannelUpdate contains the expected
                                                                // short channel id.
-                                                               if failing_route_hop.short_channel_id == chan_update.contents.short_channel_id {
+                                                               if failing_route_hop.short_channel_id
+                                                                       == chan_update.contents.short_channel_id
+                                                               {
                                                                        short_channel_id = Some(failing_route_hop.short_channel_id);
                                                                } else {
                                                                        log_info!(logger, "Node provided a channel_update for which it was not authoritative, ignoring.");
                                                                }
-                                                               network_update = Some(NetworkUpdate::ChannelUpdateMessage {
-                                                                       msg: chan_update,
-                                                               })
+                                                               network_update =
+                                                                       Some(NetworkUpdate::ChannelUpdateMessage { msg: chan_update })
                                                        } else {
                                                                // The node in question intentionally encoded a 0-length channel update. This is
                                                                // likely due to https://github.com/ElementsProject/lightning/issues/6200.
@@ -669,9 +776,11 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                                                // If the channel_update had a non-zero length (i.e. was
                                                // present) but we couldn't read it, treat it as a total
                                                // node failure.
-                                               log_info!(logger,
+                                               log_info!(
+                                                       logger,
                                                        "Failed to read a channel_update of len {} in an onion",
-                                                       update_slice.len());
+                                                       update_slice.len()
+                                               );
                                        }
                                }
                        }
@@ -690,50 +799,80 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                        // Only blame the hop when a value in the HTLC doesn't match the corresponding value in the
                        // onion.
                        short_channel_id = match error_code & 0xff {
-                               18|19 => Some(route_hop.short_channel_id),
+                               18 | 19 => Some(route_hop.short_channel_id),
                                _ => None,
                        };
                } else {
                        // We can't understand their error messages and they failed to forward...they probably can't
                        // understand our forwards so it's really not worth trying any further.
-                       network_update = Some(NetworkUpdate::NodeFailure {
-                               node_id: route_hop.pubkey,
-                               is_permanent: true,
-                       });
+                       network_update =
+                               Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent: true });
                        short_channel_id = Some(route_hop.short_channel_id);
                }
 
                res = Some(FailureLearnings {
-                       network_update, short_channel_id,
-                       payment_failed_permanently: error_code & PERM == PERM && is_from_final_node
+                       network_update,
+                       short_channel_id,
+                       payment_failed_permanently: error_code & PERM == PERM && is_from_final_node,
+                       failed_within_blinded_path: false,
                });
 
                let (description, title) = errors::get_onion_error_description(error_code);
                if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
-                       log_info!(logger, "Onion Error[from {}: {}({:#x}) {}({})] {}", route_hop.pubkey, title, error_code, debug_field, log_bytes!(&err_packet.failuremsg[4..4+debug_field_size]), description);
+                       log_info!(
+                               logger,
+                               "Onion Error[from {}: {}({:#x}) {}({})] {}",
+                               route_hop.pubkey,
+                               title,
+                               error_code,
+                               debug_field,
+                               log_bytes!(&err_packet.failuremsg[4..4 + debug_field_size]),
+                               description
+                       );
                } else {
-                       log_info!(logger, "Onion Error[from {}: {}({:#x})] {}", route_hop.pubkey, title, error_code, description);
+                       log_info!(
+                               logger,
+                               "Onion Error[from {}: {}({:#x})] {}",
+                               route_hop.pubkey,
+                               title,
+                               error_code,
+                               description
+                       );
                }
-       }).expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
+       };
+
+       construct_onion_keys_callback(secp_ctx, &path, session_priv, callback)
+               .expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
+
        if let Some(FailureLearnings {
-               network_update, short_channel_id, payment_failed_permanently
-       }) = res {
+               network_update,
+               short_channel_id,
+               payment_failed_permanently,
+               failed_within_blinded_path,
+       }) = res
+       {
                DecodedOnionFailure {
-                       network_update, short_channel_id, payment_failed_permanently,
+                       network_update,
+                       short_channel_id,
+                       payment_failed_permanently,
+                       failed_within_blinded_path,
                        #[cfg(test)]
                        onion_error_code: error_code_ret,
                        #[cfg(test)]
-                       onion_error_data: error_packet_ret
+                       onion_error_data: error_packet_ret,
                }
        } else {
                // only not set either packet unparseable or hmac does not match with any
                // payment not retryable only when garbage is from the final node
                DecodedOnionFailure {
-                       network_update: None, short_channel_id: None, payment_failed_permanently: is_from_final_node,
+                       network_update: None,
+                       short_channel_id: None,
+                       payment_failed_permanently: is_from_final_node,
+                       failed_within_blinded_path: false,
                        #[cfg(test)]
                        onion_error_code: None,
                        #[cfg(test)]
-                       onion_error_data: None
+                       onion_error_data: None,
                }
        }
 }
@@ -745,13 +884,8 @@ pub(super) struct HTLCFailReason(HTLCFailReasonRepr);
 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 #[cfg_attr(test, derive(PartialEq))]
 enum HTLCFailReasonRepr {
-       LightningError {
-               err: msgs::OnionErrorPacket,
-       },
-       Reason {
-               failure_code: u16,
-               data: Vec<u8>,
-       }
+       LightningError { err: msgs::OnionErrorPacket },
+       Reason { failure_code: u16, data: Vec<u8> },
 }
 
 impl core::fmt::Debug for HTLCFailReason {
@@ -762,7 +896,7 @@ impl core::fmt::Debug for HTLCFailReason {
                        },
                        HTLCFailReasonRepr::LightningError { .. } => {
                                write!(f, "pre-built LightningError")
-                       }
+                       },
                }
        }
 }
@@ -789,6 +923,7 @@ impl_writeable_tlv_based_enum!(HTLCFailReasonRepr,
 ;);
 
 impl HTLCFailReason {
+       #[rustfmt::skip]
        pub(super) fn reason(failure_code: u16, data: Vec<u8>) -> Self {
                const BADONION: u16 = 0x8000;
                const PERM: u16 = 0x4000;
@@ -839,28 +974,42 @@ impl HTLCFailReason {
                Self(HTLCFailReasonRepr::LightningError { err: msg.reason.clone() })
        }
 
-       pub(super) fn get_encrypted_failure_packet(&self, incoming_packet_shared_secret: &[u8; 32], phantom_shared_secret: &Option<[u8; 32]>)
-       -> msgs::OnionErrorPacket {
+       pub(super) fn get_encrypted_failure_packet(
+               &self, incoming_packet_shared_secret: &[u8; 32], phantom_shared_secret: &Option<[u8; 32]>,
+       ) -> msgs::OnionErrorPacket {
                match self.0 {
                        HTLCFailReasonRepr::Reason { ref failure_code, ref data } => {
                                if let Some(phantom_ss) = phantom_shared_secret {
-                                       let phantom_packet = build_failure_packet(phantom_ss, *failure_code, &data[..]).encode();
-                                       let encrypted_phantom_packet = encrypt_failure_packet(phantom_ss, &phantom_packet);
-                                       encrypt_failure_packet(incoming_packet_shared_secret, &encrypted_phantom_packet.data[..])
+                                       let phantom_packet =
+                                               build_failure_packet(phantom_ss, *failure_code, &data[..]).encode();
+                                       let encrypted_phantom_packet =
+                                               encrypt_failure_packet(phantom_ss, &phantom_packet);
+                                       encrypt_failure_packet(
+                                               incoming_packet_shared_secret,
+                                               &encrypted_phantom_packet.data[..],
+                                       )
                                } else {
-                                       let packet = build_failure_packet(incoming_packet_shared_secret, *failure_code, &data[..]).encode();
+                                       let packet = build_failure_packet(
+                                               incoming_packet_shared_secret,
+                                               *failure_code,
+                                               &data[..],
+                                       )
+                                       .encode();
                                        encrypt_failure_packet(incoming_packet_shared_secret, &packet)
                                }
                        },
                        HTLCFailReasonRepr::LightningError { ref err } => {
                                encrypt_failure_packet(incoming_packet_shared_secret, &err.data)
-                       }
+                       },
                }
        }
 
        pub(super) fn decode_onion_failure<T: secp256k1::Signing, L: Deref>(
-               &self, secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource
-       ) -> DecodedOnionFailure where L::Target: Logger {
+               &self, secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource,
+       ) -> DecodedOnionFailure
+       where
+               L::Target: Logger,
+       {
                match self.0 {
                        HTLCFailReasonRepr::LightningError { ref err } => {
                                process_onion_failure(secp_ctx, logger, &htlc_source, err.data.clone())
@@ -877,13 +1026,16 @@ impl HTLCFailReason {
                                                network_update: None,
                                                payment_failed_permanently: false,
                                                short_channel_id: Some(path.hops[0].short_channel_id),
+                                               failed_within_blinded_path: false,
                                                #[cfg(test)]
                                                onion_error_code: Some(*failure_code),
                                                #[cfg(test)]
                                                onion_error_data: Some(data.clone()),
                                        }
-                               } else { unreachable!(); }
-                       }
+                               } else {
+                                       unreachable!();
+                               }
+                       },
                }
        }
 }
@@ -895,7 +1047,7 @@ pub(crate) trait NextPacketBytes: AsMut<[u8]> {
 }
 
 impl NextPacketBytes for FixedSizeOnionPacket {
-       fn new(_len: usize) -> Self  {
+       fn new(_len: usize) -> Self {
                Self([0 as u8; ONION_DATA_LEN])
        }
 }
@@ -922,35 +1074,47 @@ pub(crate) enum Hop {
        },
 }
 
+impl Hop {
+       pub(crate) fn is_intro_node_blinded_forward(&self) -> bool {
+               match self {
+                       Self::Forward {
+                               next_hop_data:
+                                       msgs::InboundOnionPayload::BlindedForward {
+                                               intro_node_blinding_point: Some(_), ..
+                                       },
+                               ..
+                       } => true,
+                       _ => false,
+               }
+       }
+}
+
 /// Error returned when we fail to decode the onion packet.
 #[derive(Debug)]
 pub(crate) enum OnionDecodeErr {
        /// The HMAC of the onion packet did not match the hop data.
-       Malformed {
-               err_msg: &'static str,
-               err_code: u16,
-       },
+       Malformed { err_msg: &'static str, err_code: u16 },
        /// We failed to decode the onion payload.
-       Relay {
-               err_msg: &'static str,
-               err_code: u16,
-       },
+       Relay { err_msg: &'static str, err_code: u16 },
 }
 
 pub(crate) fn decode_next_payment_hop<NS: Deref>(
        shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: PaymentHash,
        blinding_point: Option<PublicKey>, node_signer: &NS,
-) -> Result<Hop, OnionDecodeErr> where NS::Target: NodeSigner {
+) -> Result<Hop, OnionDecodeErr>
+where
+       NS::Target: NodeSigner,
+{
        match decode_next_hop(
-               shared_secret, hop_data, hmac_bytes, Some(payment_hash), (blinding_point, node_signer)
+               shared_secret,
+               hop_data,
+               hmac_bytes,
+               Some(payment_hash),
+               (blinding_point, node_signer),
        ) {
                Ok((next_hop_data, None)) => Ok(Hop::Receive(next_hop_data)),
                Ok((next_hop_data, Some((next_hop_hmac, FixedSizeOnionPacket(new_packet_bytes))))) => {
-                       Ok(Hop::Forward {
-                               next_hop_data,
-                               next_hop_hmac,
-                               new_packet_bytes
-                       })
+                       Ok(Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes })
                },
                Err(e) => Err(e),
        }
@@ -961,27 +1125,35 @@ pub(crate) fn decode_next_payment_hop<NS: Deref>(
 pub fn create_payment_onion<T: secp256k1::Signing>(
        secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, total_msat: u64,
        recipient_onion: RecipientOnionFields, cur_block_height: u32, payment_hash: &PaymentHash,
-       keysend_preimage: &Option<PaymentPreimage>, prng_seed: [u8; 32]
+       keysend_preimage: &Option<PaymentPreimage>, prng_seed: [u8; 32],
 ) -> Result<(msgs::OnionPacket, u64, u32), APIError> {
-       let onion_keys = construct_onion_keys(&secp_ctx, &path, &session_priv)
-               .map_err(|_| APIError::InvalidRoute{
-                       err: "Pubkey along hop was maliciously selected".to_owned()
-               })?;
+       let onion_keys = construct_onion_keys(&secp_ctx, &path, &session_priv).map_err(|_| {
+               APIError::InvalidRoute { err: "Pubkey along hop was maliciously selected".to_owned() }
+       })?;
        let (onion_payloads, htlc_msat, htlc_cltv) = build_onion_payloads(
-               &path, total_msat, recipient_onion, cur_block_height, keysend_preimage
+               &path,
+               total_msat,
+               recipient_onion,
+               cur_block_height,
+               keysend_preimage,
        )?;
        let onion_packet = construct_onion_packet(onion_payloads, onion_keys, prng_seed, payment_hash)
-               .map_err(|_| APIError::InvalidRoute{
-                       err: "Route size too large considering onion data".to_owned()
+               .map_err(|_| APIError::InvalidRoute {
+                       err: "Route size too large considering onion data".to_owned(),
                })?;
        Ok((onion_packet, htlc_msat, htlc_cltv))
 }
 
-pub(crate) fn decode_next_untagged_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], read_args: T) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
+pub(crate) fn decode_next_untagged_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
+       shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], read_args: T,
+) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
        decode_next_hop(shared_secret, hop_data, hmac_bytes, None, read_args)
 }
 
-fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: Option<PaymentHash>, read_args: T) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
+fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
+       shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32],
+       payment_hash: Option<PaymentHash>, read_args: T,
+) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
        let (rho, mu) = gen_rho_mu_from_shared_secret(&shared_secret);
        let mut hmac = HmacEngine::<Sha256>::new(&mu);
        hmac.input(hop_data);
@@ -1000,11 +1172,14 @@ fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(shared_secret: [u8
        match R::read(&mut chacha_stream, read_args) {
                Err(err) => {
                        let error_code = match err {
-                               msgs::DecodeError::UnknownVersion => 0x4000 | 1, // unknown realm byte
-                               msgs::DecodeError::UnknownRequiredFeature|
-                               msgs::DecodeError::InvalidValue|
-                               msgs::DecodeError::ShortRead => 0x4000 | 22, // invalid_onion_payload
-                               _ => 0x2000 | 2, // Should never happen
+                               // Unknown realm byte
+                               msgs::DecodeError::UnknownVersion => 0x4000 | 1,
+                               // invalid_onion_payload
+                               msgs::DecodeError::UnknownRequiredFeature
+                               | msgs::DecodeError::InvalidValue
+                               | msgs::DecodeError::ShortRead => 0x4000 | 22,
+                               // Should never happen
+                               _ => 0x2000 | 2,
                        };
                        return Err(OnionDecodeErr::Relay {
                                err_msg: "Unable to decode our hop data",
@@ -1054,7 +1229,7 @@ fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(shared_secret: [u8
                                // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
                                // fill the onion hop data we'll forward to our next-hop peer.
                                chacha_stream.chacha.process_in_place(&mut new_packet_bytes.as_mut()[read_pos..]);
-                               return Ok((msg, Some((hmac, new_packet_bytes)))) // This packet needs forwarding
+                               return Ok((msg, Some((hmac, new_packet_bytes)))); // This packet needs forwarding
                        }
                },
        }
@@ -1063,21 +1238,24 @@ fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(shared_secret: [u8
 #[cfg(test)]
 mod tests {
        use crate::io;
-       use crate::prelude::*;
-       use crate::ln::PaymentHash;
        use crate::ln::features::{ChannelFeatures, NodeFeatures};
-       use crate::routing::router::{Path, Route, RouteHop};
        use crate::ln::msgs;
-       use crate::util::ser::{Writeable, Writer, VecWriter};
+       use crate::ln::PaymentHash;
+       use crate::routing::router::{Path, Route, RouteHop};
+       use crate::util::ser::{VecWriter, Writeable, Writer};
+
+       #[allow(unused_imports)]
+       use crate::prelude::*;
 
        use bitcoin::hashes::hex::FromHex;
        use bitcoin::secp256k1::Secp256k1;
-       use bitcoin::secp256k1::{PublicKey,SecretKey};
+       use bitcoin::secp256k1::{PublicKey, SecretKey};
 
        use super::OnionKeys;
 
        fn get_test_session_key() -> SecretKey {
-               SecretKey::from_slice(&<Vec<u8>>::from_hex("4141414141414141414141414141414141414141414141414141414141414141").unwrap()[..]).unwrap()
+               let hex = "4141414141414141414141414141414141414141414141414141414141414141";
+               SecretKey::from_slice(&<Vec<u8>>::from_hex(hex).unwrap()[..]).unwrap()
        }
 
        fn build_test_onion_keys() -> Vec<OnionKeys> {
@@ -1115,7 +1293,9 @@ mod tests {
                        route_params: None,
                };
 
-               let onion_keys = super::construct_onion_keys(&secp_ctx, &route.paths[0], &get_test_session_key()).unwrap();
+               let onion_keys =
+                       super::construct_onion_keys(&secp_ctx, &route.paths[0], &get_test_session_key())
+                               .unwrap();
                assert_eq!(onion_keys.len(), route.paths[0].hops.len());
                onion_keys
        }
@@ -1126,35 +1306,110 @@ mod tests {
 
                // Test generation of ephemeral keys and secrets. These values used to be part of the BOLT4
                // test vectors, but have since been removed. We keep them as they provide test coverage.
-               assert_eq!(onion_keys[0].shared_secret.secret_bytes(), <Vec<u8>>::from_hex("53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66").unwrap()[..]);
-               assert_eq!(onion_keys[0].blinding_factor[..], <Vec<u8>>::from_hex("2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36").unwrap()[..]);
-               assert_eq!(onion_keys[0].ephemeral_pubkey.serialize()[..], <Vec<u8>>::from_hex("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]);
-               assert_eq!(onion_keys[0].rho, <Vec<u8>>::from_hex("ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986").unwrap()[..]);
-               assert_eq!(onion_keys[0].mu, <Vec<u8>>::from_hex("b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba").unwrap()[..]);
-
-               assert_eq!(onion_keys[1].shared_secret.secret_bytes(), <Vec<u8>>::from_hex("a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae").unwrap()[..]);
-               assert_eq!(onion_keys[1].blinding_factor[..], <Vec<u8>>::from_hex("bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f").unwrap()[..]);
-               assert_eq!(onion_keys[1].ephemeral_pubkey.serialize()[..], <Vec<u8>>::from_hex("028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2").unwrap()[..]);
-               assert_eq!(onion_keys[1].rho, <Vec<u8>>::from_hex("450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59").unwrap()[..]);
-               assert_eq!(onion_keys[1].mu, <Vec<u8>>::from_hex("05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9").unwrap()[..]);
-
-               assert_eq!(onion_keys[2].shared_secret.secret_bytes(), <Vec<u8>>::from_hex("3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc").unwrap()[..]);
-               assert_eq!(onion_keys[2].blinding_factor[..], <Vec<u8>>::from_hex("a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5").unwrap()[..]);
-               assert_eq!(onion_keys[2].ephemeral_pubkey.serialize()[..], <Vec<u8>>::from_hex("03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0").unwrap()[..]);
-               assert_eq!(onion_keys[2].rho, <Vec<u8>>::from_hex("11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea").unwrap()[..]);
-               assert_eq!(onion_keys[2].mu, <Vec<u8>>::from_hex("caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78").unwrap()[..]);
-
-               assert_eq!(onion_keys[3].shared_secret.secret_bytes(), <Vec<u8>>::from_hex("21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d").unwrap()[..]);
-               assert_eq!(onion_keys[3].blinding_factor[..], <Vec<u8>>::from_hex("7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262").unwrap()[..]);
-               assert_eq!(onion_keys[3].ephemeral_pubkey.serialize()[..], <Vec<u8>>::from_hex("031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595").unwrap()[..]);
-               assert_eq!(onion_keys[3].rho, <Vec<u8>>::from_hex("cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e").unwrap()[..]);
-               assert_eq!(onion_keys[3].mu, <Vec<u8>>::from_hex("5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9").unwrap()[..]);
-
-               assert_eq!(onion_keys[4].shared_secret.secret_bytes(), <Vec<u8>>::from_hex("b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328").unwrap()[..]);
-               assert_eq!(onion_keys[4].blinding_factor[..], <Vec<u8>>::from_hex("c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205").unwrap()[..]);
-               assert_eq!(onion_keys[4].ephemeral_pubkey.serialize()[..], <Vec<u8>>::from_hex("03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4").unwrap()[..]);
-               assert_eq!(onion_keys[4].rho, <Vec<u8>>::from_hex("034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b").unwrap()[..]);
-               assert_eq!(onion_keys[4].mu, <Vec<u8>>::from_hex("8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a").unwrap()[..]);
+               let hex = "53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66";
+               assert_eq!(
+                       onion_keys[0].shared_secret.secret_bytes(),
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36";
+               assert_eq!(onion_keys[0].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619";
+               assert_eq!(
+                       onion_keys[0].ephemeral_pubkey.serialize()[..],
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986";
+               assert_eq!(onion_keys[0].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba";
+               assert_eq!(onion_keys[0].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae";
+               assert_eq!(
+                       onion_keys[1].shared_secret.secret_bytes(),
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f";
+               assert_eq!(onion_keys[1].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2";
+               assert_eq!(
+                       onion_keys[1].ephemeral_pubkey.serialize()[..],
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59";
+               assert_eq!(onion_keys[1].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9";
+               assert_eq!(onion_keys[1].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc";
+               assert_eq!(
+                       onion_keys[2].shared_secret.secret_bytes(),
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5";
+               assert_eq!(onion_keys[2].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0";
+               assert_eq!(
+                       onion_keys[2].ephemeral_pubkey.serialize()[..],
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea";
+               assert_eq!(onion_keys[2].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78";
+               assert_eq!(onion_keys[2].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d";
+               assert_eq!(
+                       onion_keys[3].shared_secret.secret_bytes(),
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262";
+               assert_eq!(onion_keys[3].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595";
+               assert_eq!(
+                       onion_keys[3].ephemeral_pubkey.serialize()[..],
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e";
+               assert_eq!(onion_keys[3].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9";
+               assert_eq!(onion_keys[3].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328";
+               assert_eq!(
+                       onion_keys[4].shared_secret.secret_bytes(),
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205";
+               assert_eq!(onion_keys[4].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4";
+               assert_eq!(
+                       onion_keys[4].ephemeral_pubkey.serialize()[..],
+                       <Vec<u8>>::from_hex(hex).unwrap()[..]
+               );
+
+               let hex = "034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b";
+               assert_eq!(onion_keys[4].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
+
+               let hex = "8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a";
+               assert_eq!(onion_keys[4].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
 
                // Packet creation test vectors from BOLT 4 (see
                // https://github.com/lightning/bolts/blob/16973e2b857e853308cafd59e42fa830d75b1642/bolt04/onion-test.json).
@@ -1219,26 +1474,37 @@ mod tests {
                let mut w = VecWriter(Vec::new());
                payloads[0].write(&mut w).unwrap();
                let hop_1_serialized_payload = w.0;
-               let expected_serialized_hop_1_payload = &<Vec<u8>>::from_hex("1202023a98040205dc06080000000000000001").unwrap()[..];
+               let hex = "1202023a98040205dc06080000000000000001";
+               let expected_serialized_hop_1_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
                assert_eq!(hop_1_serialized_payload, expected_serialized_hop_1_payload);
 
                w = VecWriter(Vec::new());
                payloads[2].write(&mut w).unwrap();
                let hop_3_serialized_payload = w.0;
-               let expected_serialized_hop_3_payload = &<Vec<u8>>::from_hex("12020230d4040204e206080000000000000003").unwrap()[..];
+               let hex = "12020230d4040204e206080000000000000003";
+               let expected_serialized_hop_3_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
                assert_eq!(hop_3_serialized_payload, expected_serialized_hop_3_payload);
 
                w = VecWriter(Vec::new());
                payloads[3].write(&mut w).unwrap();
                let hop_4_serialized_payload = w.0;
-               let expected_serialized_hop_4_payload = &<Vec<u8>>::from_hex("1202022710040203e806080000000000000004").unwrap()[..];
+               let hex = "1202022710040203e806080000000000000004";
+               let expected_serialized_hop_4_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
                assert_eq!(hop_4_serialized_payload, expected_serialized_hop_4_payload);
 
-               let pad_keytype_seed = super::gen_pad_from_shared_secret(&get_test_session_key().secret_bytes());
+               let pad_keytype_seed =
+                       super::gen_pad_from_shared_secret(&get_test_session_key().secret_bytes());
 
-               let packet: msgs::OnionPacket = super::construct_onion_packet_with_writable_hopdata::<_>(payloads, onion_keys, pad_keytype_seed, &PaymentHash([0x42; 32])).unwrap();
+               let packet: msgs::OnionPacket = super::construct_onion_packet_with_writable_hopdata::<_>(
+                       payloads,
+                       onion_keys,
+                       pad_keytype_seed,
+                       &PaymentHash([0x42; 32]),
+               )
+               .unwrap();
 
-               assert_eq!(packet.encode(), <Vec<u8>>::from_hex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unwrap());
+               let hex = 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
+               assert_eq!(packet.encode(), <Vec<u8>>::from_hex(hex).unwrap());
        }
 
        #[test]
@@ -1246,27 +1512,49 @@ mod tests {
                // Returning Errors test vectors from BOLT 4
 
                let onion_keys = build_test_onion_keys();
-               let onion_error = super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
-               assert_eq!(onion_error.encode(), <Vec<u8>>::from_hex("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").unwrap());
-
-               let onion_packet_1 = super::encrypt_failure_packet(onion_keys[4].shared_secret.as_ref(), &onion_error.encode()[..]);
-               assert_eq!(onion_packet_1.data, <Vec<u8>>::from_hex("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").unwrap());
+               let onion_error =
+                       super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
+               let hex = "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";
+               assert_eq!(onion_error.encode(), <Vec<u8>>::from_hex(hex).unwrap());
+
+               let onion_packet_1 = super::encrypt_failure_packet(
+                       onion_keys[4].shared_secret.as_ref(),
+                       &onion_error.encode()[..],
+               );
+               let hex = "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";
+               assert_eq!(onion_packet_1.data, <Vec<u8>>::from_hex(hex).unwrap());
 
-               let onion_packet_2 = super::encrypt_failure_packet(onion_keys[3].shared_secret.as_ref(), &onion_packet_1.data[..]);
-               assert_eq!(onion_packet_2.data, <Vec<u8>>::from_hex("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").unwrap());
+               let onion_packet_2 = super::encrypt_failure_packet(
+                       onion_keys[3].shared_secret.as_ref(),
+                       &onion_packet_1.data[..],
+               );
+               let hex = "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";
+               assert_eq!(onion_packet_2.data, <Vec<u8>>::from_hex(hex).unwrap());
 
-               let onion_packet_3 = super::encrypt_failure_packet(onion_keys[2].shared_secret.as_ref(), &onion_packet_2.data[..]);
-               assert_eq!(onion_packet_3.data, <Vec<u8>>::from_hex("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").unwrap());
+               let onion_packet_3 = super::encrypt_failure_packet(
+                       onion_keys[2].shared_secret.as_ref(),
+                       &onion_packet_2.data[..],
+               );
+               let hex = "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";
+               assert_eq!(onion_packet_3.data, <Vec<u8>>::from_hex(hex).unwrap());
 
-               let onion_packet_4 = super::encrypt_failure_packet(onion_keys[1].shared_secret.as_ref(), &onion_packet_3.data[..]);
-               assert_eq!(onion_packet_4.data, <Vec<u8>>::from_hex("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").unwrap());
+               let onion_packet_4 = super::encrypt_failure_packet(
+                       onion_keys[1].shared_secret.as_ref(),
+                       &onion_packet_3.data[..],
+               );
+               let hex = "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";
+               assert_eq!(onion_packet_4.data, <Vec<u8>>::from_hex(hex).unwrap());
 
-               let onion_packet_5 = super::encrypt_failure_packet(onion_keys[0].shared_secret.as_ref(), &onion_packet_4.data[..]);
-               assert_eq!(onion_packet_5.data, <Vec<u8>>::from_hex("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").unwrap());
+               let onion_packet_5 = super::encrypt_failure_packet(
+                       onion_keys[0].shared_secret.as_ref(),
+                       &onion_packet_4.data[..],
+               );
+               let hex = "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";
+               assert_eq!(onion_packet_5.data, <Vec<u8>>::from_hex(hex).unwrap());
        }
 
        struct RawOnionHopData {
-               data: Vec<u8>
+               data: Vec<u8>,
        }
        impl RawOnionHopData {
                fn new(orig: msgs::OutboundOnionPayload) -> Self {