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use bitcoin::secp256k1::PublicKey;
use bitcoin::secp256k1::ecdh::SharedSecret;
use crate::ln::msgs::DecodeError;
use crate::ln::onion_utils;
use super::blinded_path::{BlindedPath, ForwardTlvs, ReceiveTlvs};
use super::messenger::CustomOnionMessageHandler;
use crate::util::chacha20poly1305rfc::{ChaChaPolyReadAdapter, ChaChaPolyWriteAdapter};
use crate::util::ser::{BigSize, FixedLengthReader, LengthRead, LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer};
use core::cmp;
use crate::io::{self, Read};
use crate::prelude::*;
pub(super) const SMALL_PACKET_HOP_DATA_LEN: usize = 1300;
pub(super) const BIG_PACKET_HOP_DATA_LEN: usize = 32768;
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct Packet {
pub(super) version: u8,
pub(super) public_key: PublicKey,
pub(super) hop_data: Vec<u8>,
pub(super) hmac: [u8; 32],
}
impl onion_utils::Packet for Packet {
type Data = Vec<u8>;
fn new(public_key: PublicKey, hop_data: Vec<u8>, hmac: [u8; 32]) -> Packet {
Self {
version: 0,
public_key,
hop_data,
hmac,
}
}
}
impl Writeable for Packet {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
self.version.write(w)?;
self.public_key.write(w)?;
w.write_all(&self.hop_data)?;
self.hmac.write(w)?;
Ok(())
}
}
impl LengthReadable for Packet {
fn read<R: LengthRead>(r: &mut R) -> Result<Self, DecodeError> {
const READ_BUFFER_SIZE: usize = 4096;
let version = Readable::read(r)?;
let public_key = Readable::read(r)?;
let mut hop_data = Vec::new();
let hop_data_len = r.total_bytes().saturating_sub(66) as usize; let mut read_idx = 0;
while read_idx < hop_data_len {
let mut read_buffer = [0; READ_BUFFER_SIZE];
let read_amt = cmp::min(hop_data_len - read_idx, READ_BUFFER_SIZE);
r.read_exact(&mut read_buffer[..read_amt])?;
hop_data.extend_from_slice(&read_buffer[..read_amt]);
read_idx += read_amt;
}
let hmac = Readable::read(r)?;
Ok(Packet {
version,
public_key,
hop_data,
hmac,
})
}
}
pub(super) enum Payload<T: CustomOnionMessageContents> {
Forward(ForwardControlTlvs),
Receive {
control_tlvs: ReceiveControlTlvs,
reply_path: Option<BlindedPath>,
message: OnionMessageContents<T>,
}
}
#[derive(Debug)]
pub enum OnionMessageContents<T: CustomOnionMessageContents> {
Custom(T),
}
impl<T: CustomOnionMessageContents> OnionMessageContents<T> {
pub fn tlv_type(&self) -> u64 {
match self {
&OnionMessageContents::Custom(ref msg) => msg.tlv_type(),
}
}
}
impl<T: CustomOnionMessageContents> Writeable for OnionMessageContents<T> {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
match self {
OnionMessageContents::Custom(msg) => Ok(msg.write(w)?),
}
}
}
pub trait CustomOnionMessageContents: Writeable {
fn tlv_type(&self) -> u64;
}
pub(super) enum ForwardControlTlvs {
Blinded(Vec<u8>),
Unblinded(ForwardTlvs),
}
pub(super) enum ReceiveControlTlvs {
Blinded(Vec<u8>),
Unblinded(ReceiveTlvs),
}
impl<T: CustomOnionMessageContents> Writeable for (Payload<T>, [u8; 32]) {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
match &self.0 {
Payload::Forward(ForwardControlTlvs::Blinded(encrypted_bytes)) => {
_encode_varint_length_prefixed_tlv!(w, {
(4, *encrypted_bytes, vec_type)
})
},
Payload::Receive {
control_tlvs: ReceiveControlTlvs::Blinded(encrypted_bytes), reply_path, message,
} => {
_encode_varint_length_prefixed_tlv!(w, {
(2, reply_path, option),
(4, *encrypted_bytes, vec_type),
(message.tlv_type(), message, required)
})
},
Payload::Forward(ForwardControlTlvs::Unblinded(control_tlvs)) => {
let write_adapter = ChaChaPolyWriteAdapter::new(self.1, &control_tlvs);
_encode_varint_length_prefixed_tlv!(w, {
(4, write_adapter, required)
})
},
Payload::Receive {
control_tlvs: ReceiveControlTlvs::Unblinded(control_tlvs), reply_path, message,
} => {
let write_adapter = ChaChaPolyWriteAdapter::new(self.1, &control_tlvs);
_encode_varint_length_prefixed_tlv!(w, {
(2, reply_path, option),
(4, write_adapter, required),
(message.tlv_type(), message, required)
})
},
}
Ok(())
}
}
impl<H: CustomOnionMessageHandler> ReadableArgs<(SharedSecret, &H)> for Payload<<H as CustomOnionMessageHandler>::CustomMessage> {
fn read<R: Read>(r: &mut R, args: (SharedSecret, &H)) -> Result<Self, DecodeError> {
let (encrypted_tlvs_ss, handler) = args;
let v: BigSize = Readable::read(r)?;
let mut rd = FixedLengthReader::new(r, v.0);
let mut reply_path: Option<BlindedPath> = None;
let mut read_adapter: Option<ChaChaPolyReadAdapter<ControlTlvs>> = None;
let rho = onion_utils::gen_rho_from_shared_secret(&encrypted_tlvs_ss.secret_bytes());
let mut message_type: Option<u64> = None;
let mut message = None;
decode_tlv_stream_with_custom_tlv_decode!(&mut rd, {
(2, reply_path, option),
(4, read_adapter, (option: LengthReadableArgs, rho)),
}, |msg_type, msg_reader| {
if msg_type < 64 { return Ok(false) }
if message_type.is_some() { return Err(DecodeError::InvalidValue) }
message_type = Some(msg_type);
match handler.read_custom_message(msg_type, msg_reader) {
Ok(Some(msg)) => {
message = Some(msg);
Ok(true)
},
Ok(None) => Ok(false),
Err(e) => Err(e),
}
});
rd.eat_remaining().map_err(|_| DecodeError::ShortRead)?;
match read_adapter {
None => return Err(DecodeError::InvalidValue),
Some(ChaChaPolyReadAdapter { readable: ControlTlvs::Forward(tlvs)}) => {
if message_type.is_some() {
return Err(DecodeError::InvalidValue)
}
Ok(Payload::Forward(ForwardControlTlvs::Unblinded(tlvs)))
},
Some(ChaChaPolyReadAdapter { readable: ControlTlvs::Receive(tlvs)}) => {
if message.is_none() { return Err(DecodeError::InvalidValue) }
Ok(Payload::Receive {
control_tlvs: ReceiveControlTlvs::Unblinded(tlvs),
reply_path,
message: OnionMessageContents::Custom(message.unwrap()),
})
}
}
}
}
pub(super) enum ControlTlvs {
Forward(ForwardTlvs),
Receive(ReceiveTlvs),
}
impl Readable for ControlTlvs {
fn read<R: Read>(mut r: &mut R) -> Result<Self, DecodeError> {
let mut _padding: Option<Padding> = None;
let mut _short_channel_id: Option<u64> = None;
let mut next_node_id: Option<PublicKey> = None;
let mut path_id: Option<[u8; 32]> = None;
let mut next_blinding_override: Option<PublicKey> = None;
decode_tlv_stream!(&mut r, {
(1, _padding, option),
(2, _short_channel_id, option),
(4, next_node_id, option),
(6, path_id, option),
(8, next_blinding_override, option),
});
let valid_fwd_fmt = next_node_id.is_some() && path_id.is_none();
let valid_recv_fmt = next_node_id.is_none() && next_blinding_override.is_none();
let payload_fmt = if valid_fwd_fmt {
ControlTlvs::Forward(ForwardTlvs {
next_node_id: next_node_id.unwrap(),
next_blinding_override,
})
} else if valid_recv_fmt {
ControlTlvs::Receive(ReceiveTlvs {
path_id,
})
} else {
return Err(DecodeError::InvalidValue)
};
Ok(payload_fmt)
}
}
pub(crate) struct Padding {}
impl Readable for Padding {
#[inline]
fn read<R: Read>(reader: &mut R) -> Result<Self, DecodeError> {
loop {
let mut buf = [0; 8192];
if reader.read(&mut buf[..])? == 0 { break; }
}
Ok(Self {})
}
}