//! Structs and enums useful for constructing and reading an onion message packet.
use bitcoin::secp256k1::PublicKey;
+use bitcoin::secp256k1::ecdh::SharedSecret;
-use ln::msgs::DecodeError;
-use ln::onion_utils;
-use super::blinded_route::{ForwardTlvs, ReceiveTlvs};
-use util::chacha20poly1305rfc::ChaChaPolyWriteAdapter;
-use util::ser::{LengthRead, LengthReadable, Readable, Writeable, Writer};
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::message::{ForwardTlvs, ReceiveTlvs};
+use crate::blinded_path::utils::Padding;
+use crate::ln::msgs::DecodeError;
+use crate::ln::onion_utils;
+use super::messenger::CustomOnionMessageHandler;
+use super::offers::OffersMessage;
+use crate::util::chacha20poly1305rfc::{ChaChaPolyReadAdapter, ChaChaPolyWriteAdapter};
+use crate::util::logger::Logger;
+use crate::util::ser::{BigSize, FixedLengthReader, LengthRead, LengthReadable, LengthReadableArgs, Readable, ReadableArgs, Writeable, Writer};
use core::cmp;
-use io;
-use prelude::*;
+use crate::io::{self, Read};
+use crate::prelude::*;
// Per the spec, an onion message packet's `hop_data` field length should be
// SMALL_PACKET_HOP_DATA_LEN if it fits, else BIG_PACKET_HOP_DATA_LEN if it fits.
pub(super) const SMALL_PACKET_HOP_DATA_LEN: usize = 1300;
pub(super) const BIG_PACKET_HOP_DATA_LEN: usize = 32768;
-#[derive(Clone, Debug, PartialEq)]
-pub(crate) struct Packet {
- version: u8,
- public_key: PublicKey,
+/// Packet of hop data for next peer
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+pub struct Packet {
+ /// Bolt 04 version number
+ pub version: u8,
+ /// A random sepc256k1 point, used to build the ECDH shared secret to decrypt hop_data
+ pub public_key: PublicKey,
+ /// Encrypted payload for the next hop
+ //
// Unlike the onion packets used for payments, onion message packets can have payloads greater
// than 1300 bytes.
// TODO: if 1300 ends up being the most common size, optimize this to be:
// enum { ThirteenHundred([u8; 1300]), VarLen(Vec<u8>) }
- hop_data: Vec<u8>,
- hmac: [u8; 32],
+ pub hop_data: Vec<u8>,
+ /// HMAC to verify the integrity of hop_data
+ pub hmac: [u8; 32],
}
impl onion_utils::Packet for Packet {
let public_key = Readable::read(r)?;
let mut hop_data = Vec::new();
- let hop_data_len = r.total_bytes() as usize - 66; // 1 (version) + 33 (pubkey) + 32 (HMAC) = 66
+ let hop_data_len = r.total_bytes().saturating_sub(66) as usize; // 1 (version) + 33 (pubkey) + 32 (HMAC) = 66
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]);
+ r.read_exact(&mut read_buffer[..read_amt])?;
hop_data.extend_from_slice(&read_buffer[..read_amt]);
read_idx += read_amt;
}
/// Onion message payloads contain "control" TLVs and "data" TLVs. Control TLVs are used to route
/// the onion message from hop to hop and for path verification, whereas data TLVs contain the onion
/// message content itself, such as an invoice request.
-pub(super) enum Payload {
+pub(super) enum Payload<T: OnionMessageContents> {
/// This payload is for an intermediate hop.
Forward(ForwardControlTlvs),
/// This payload is for the final hop.
Receive {
control_tlvs: ReceiveControlTlvs,
- // Coming soon:
- // reply_path: Option<BlindedRoute>,
- // message: Message,
+ reply_path: Option<BlindedPath>,
+ message: T,
}
}
-// Coming soon:
-// enum Message {
-// InvoiceRequest(InvoiceRequest),
-// Invoice(Invoice),
-// InvoiceError(InvoiceError),
-// CustomMessage<T>,
-// }
+/// The contents of an [`OnionMessage`] as read from the wire.
+///
+/// [`OnionMessage`]: crate::ln::msgs::OnionMessage
+#[derive(Debug)]
+pub enum ParsedOnionMessageContents<T: OnionMessageContents> {
+ /// A message related to BOLT 12 Offers.
+ Offers(OffersMessage),
+ /// A custom onion message specified by the user.
+ Custom(T),
+}
+
+impl<T: OnionMessageContents> OnionMessageContents for ParsedOnionMessageContents<T> {
+ /// Returns the type that was used to decode the message payload.
+ ///
+ /// This is not exported to bindings users as methods on non-cloneable enums are not currently exportable
+ fn tlv_type(&self) -> u64 {
+ match self {
+ &ParsedOnionMessageContents::Offers(ref msg) => msg.tlv_type(),
+ &ParsedOnionMessageContents::Custom(ref msg) => msg.tlv_type(),
+ }
+ }
+}
+
+impl<T: OnionMessageContents> Writeable for ParsedOnionMessageContents<T> {
+ fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+ match self {
+ ParsedOnionMessageContents::Offers(msg) => Ok(msg.write(w)?),
+ ParsedOnionMessageContents::Custom(msg) => Ok(msg.write(w)?),
+ }
+ }
+}
+
+/// The contents of an onion message.
+pub trait OnionMessageContents: Writeable + core::fmt::Debug {
+ /// Returns the TLV type identifying the message contents. MUST be >= 64.
+ fn tlv_type(&self) -> u64;
+}
/// Forward control TLVs in their blinded and unblinded form.
pub(super) enum ForwardControlTlvs {
- /// If we're sending to a blinded route, the node that constructed the blinded route has provided
+ /// If we're sending to a blinded path, the node that constructed the blinded path has provided
/// this hop's control TLVs, already encrypted into bytes.
Blinded(Vec<u8>),
/// If we're constructing an onion message hop through an intermediate unblinded node, we'll need
/// to construct the intermediate hop's control TLVs in their unblinded state to avoid encoding
- /// them into an intermediate Vec. See [`super::blinded_route::ForwardTlvs`] for more info.
+ /// them into an intermediate Vec. See [`crate::blinded_path::message::ForwardTlvs`] for more
+ /// info.
Unblinded(ForwardTlvs),
}
pub(super) enum ReceiveControlTlvs {
/// See [`ForwardControlTlvs::Blinded`].
Blinded(Vec<u8>),
- /// See [`ForwardControlTlvs::Unblinded`] and [`super::blinded_route::ReceiveTlvs`].
+ /// See [`ForwardControlTlvs::Unblinded`] and [`crate::blinded_path::message::ReceiveTlvs`].
Unblinded(ReceiveTlvs),
}
// Uses the provided secret to simultaneously encode and encrypt the unblinded control TLVs.
-impl Writeable for (Payload, [u8; 32]) {
+impl<T: OnionMessageContents> 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)) |
- Payload::Receive { control_tlvs: ReceiveControlTlvs::Blinded(encrypted_bytes)} => {
- encode_varint_length_prefixed_tlv!(w, {
- (4, encrypted_bytes, vec_type)
+ Payload::Forward(ForwardControlTlvs::Blinded(encrypted_bytes)) => {
+ _encode_varint_length_prefixed_tlv!(w, {
+ (4, *encrypted_bytes, required_vec)
+ })
+ },
+ Payload::Receive {
+ control_tlvs: ReceiveControlTlvs::Blinded(encrypted_bytes), reply_path, message,
+ } => {
+ _encode_varint_length_prefixed_tlv!(w, {
+ (2, reply_path, option),
+ (4, *encrypted_bytes, required_vec),
+ (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, {
+ _encode_varint_length_prefixed_tlv!(w, {
(4, write_adapter, required)
})
},
- Payload::Receive { control_tlvs: ReceiveControlTlvs::Unblinded(control_tlvs)} => {
+ 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, {
- (4, write_adapter, required)
+ _encode_varint_length_prefixed_tlv!(w, {
+ (2, reply_path, option),
+ (4, write_adapter, required),
+ (message.tlv_type(), message, required)
})
},
}
Ok(())
}
}
+
+// Uses the provided secret to simultaneously decode and decrypt the control TLVs and data TLV.
+impl<H: CustomOnionMessageHandler + ?Sized, L: Logger + ?Sized> ReadableArgs<(SharedSecret, &H, &L)>
+for Payload<ParsedOnionMessageContents<<H as CustomOnionMessageHandler>::CustomMessage>> {
+ fn read<R: Read>(r: &mut R, args: (SharedSecret, &H, &L)) -> Result<Self, DecodeError> {
+ let (encrypted_tlvs_ss, handler, logger) = 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) }
+ // Don't allow reading more than one data TLV from an onion message.
+ if message_type.is_some() { return Err(DecodeError::InvalidValue) }
+
+ message_type = Some(msg_type);
+ match msg_type {
+ tlv_type if OffersMessage::is_known_type(tlv_type) => {
+ let msg = OffersMessage::read(msg_reader, (tlv_type, logger))?;
+ message = Some(ParsedOnionMessageContents::Offers(msg));
+ Ok(true)
+ },
+ _ => match handler.read_custom_message(msg_type, msg_reader)? {
+ Some(msg) => {
+ message = Some(ParsedOnionMessageContents::Custom(msg));
+ Ok(true)
+ },
+ None => Ok(false),
+ },
+ }
+ });
+ 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)}) => {
+ Ok(Payload::Receive {
+ control_tlvs: ReceiveControlTlvs::Unblinded(tlvs),
+ reply_path,
+ message: message.ok_or(DecodeError::InvalidValue)?,
+ })
+ },
+ }
+ }
+}
+
+/// When reading a packet off the wire, we don't know a priori whether the packet is to be forwarded
+/// or received. Thus we read a `ControlTlvs` rather than reading a [`ForwardTlvs`] or
+/// [`ReceiveTlvs`] directly. Also useful on the encoding side to keep forward and receive TLVs in
+/// the same iterator.
+pub(crate) enum ControlTlvs {
+ /// This onion message is intended to be forwarded.
+ Forward(ForwardTlvs),
+ /// This onion message is intended to be received.
+ Receive(ReceiveTlvs),
+}
+
+impl Readable for ControlTlvs {
+ fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+ _init_and_read_tlv_stream!(r, {
+ (1, _padding, option),
+ (2, _short_channel_id, option),
+ (4, next_node_id, option),
+ (6, path_id, option),
+ (8, next_blinding_override, option),
+ });
+ let _padding: Option<Padding> = _padding;
+ let _short_channel_id: Option<u64> = _short_channel_id;
+
+ 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)
+ }
+}
+
+impl Writeable for ControlTlvs {
+ fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+ match self {
+ Self::Forward(tlvs) => tlvs.write(w),
+ Self::Receive(tlvs) => tlvs.write(w),
+ }
+ }
+}