reth_eth_wire/p2pstream.rs
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use crate::{
capability::SharedCapabilities,
disconnect::CanDisconnect,
errors::{P2PHandshakeError, P2PStreamError},
pinger::{Pinger, PingerEvent},
DisconnectReason, HelloMessage, HelloMessageWithProtocols,
};
use alloy_primitives::{
bytes::{Buf, BufMut, Bytes, BytesMut},
hex,
};
use alloy_rlp::{Decodable, Encodable, Error as RlpError, EMPTY_LIST_CODE};
use futures::{Sink, SinkExt, StreamExt};
use pin_project::pin_project;
use reth_codecs::add_arbitrary_tests;
use reth_metrics::metrics::counter;
use reth_primitives::GotExpected;
use std::{
collections::VecDeque,
io,
pin::Pin,
task::{ready, Context, Poll},
time::Duration,
};
use tokio_stream::Stream;
use tracing::{debug, trace};
#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};
/// [`MAX_PAYLOAD_SIZE`] is the maximum size of an uncompressed message payload.
/// This is defined in [EIP-706](https://eips.ethereum.org/EIPS/eip-706).
const MAX_PAYLOAD_SIZE: usize = 16 * 1024 * 1024;
/// [`MAX_RESERVED_MESSAGE_ID`] is the maximum message ID reserved for the `p2p` subprotocol. If
/// there are any incoming messages with an ID greater than this, they are subprotocol messages.
pub const MAX_RESERVED_MESSAGE_ID: u8 = 0x0f;
/// [`MAX_P2P_MESSAGE_ID`] is the maximum message ID in use for the `p2p` subprotocol.
const MAX_P2P_MESSAGE_ID: u8 = P2PMessageID::Pong as u8;
/// [`HANDSHAKE_TIMEOUT`] determines the amount of time to wait before determining that a `p2p`
/// handshake has timed out.
pub(crate) const HANDSHAKE_TIMEOUT: Duration = Duration::from_secs(10);
/// [`PING_TIMEOUT`] determines the amount of time to wait before determining that a `p2p` ping has
/// timed out.
const PING_TIMEOUT: Duration = Duration::from_secs(15);
/// [`PING_INTERVAL`] determines the amount of time to wait between sending `p2p` ping messages
/// when the peer is responsive.
const PING_INTERVAL: Duration = Duration::from_secs(60);
/// [`MAX_P2P_CAPACITY`] is the maximum number of messages that can be buffered to be sent in the
/// `p2p` stream.
///
/// Note: this default is rather low because it is expected that the [`P2PStream`] wraps an
/// [`ECIESStream`](reth_ecies::stream::ECIESStream) which internally already buffers a few MB of
/// encoded data.
const MAX_P2P_CAPACITY: usize = 2;
/// An un-authenticated [`P2PStream`]. This is consumed and returns a [`P2PStream`] after the
/// `Hello` handshake is completed.
#[pin_project]
#[derive(Debug)]
pub struct UnauthedP2PStream<S> {
#[pin]
inner: S,
}
impl<S> UnauthedP2PStream<S> {
/// Create a new `UnauthedP2PStream` from a type `S` which implements `Stream` and `Sink`.
pub const fn new(inner: S) -> Self {
Self { inner }
}
/// Returns a reference to the inner stream.
pub const fn inner(&self) -> &S {
&self.inner
}
}
impl<S> UnauthedP2PStream<S>
where
S: Stream<Item = io::Result<BytesMut>> + Sink<Bytes, Error = io::Error> + Unpin,
{
/// Consumes the `UnauthedP2PStream` and returns a `P2PStream` after the `Hello` handshake is
/// completed successfully. This also returns the `Hello` message sent by the remote peer.
pub async fn handshake(
mut self,
hello: HelloMessageWithProtocols,
) -> Result<(P2PStream<S>, HelloMessage), P2PStreamError> {
trace!(?hello, "sending p2p hello to peer");
// send our hello message with the Sink
self.inner.send(alloy_rlp::encode(P2PMessage::Hello(hello.message())).into()).await?;
let first_message_bytes = tokio::time::timeout(HANDSHAKE_TIMEOUT, self.inner.next())
.await
.or(Err(P2PStreamError::HandshakeError(P2PHandshakeError::Timeout)))?
.ok_or(P2PStreamError::HandshakeError(P2PHandshakeError::NoResponse))??;
// let's check the compressed length first, we will need to check again once confirming
// that it contains snappy-compressed data (this will be the case for all non-p2p messages).
if first_message_bytes.len() > MAX_PAYLOAD_SIZE {
return Err(P2PStreamError::MessageTooBig {
message_size: first_message_bytes.len(),
max_size: MAX_PAYLOAD_SIZE,
})
}
// The first message sent MUST be a hello OR disconnect message
//
// If the first message is a disconnect message, we should not decode using
// Decodable::decode, because the first message (either Disconnect or Hello) is not snappy
// compressed, and the Decodable implementation assumes that non-hello messages are snappy
// compressed.
let their_hello = match P2PMessage::decode(&mut &first_message_bytes[..]) {
Ok(P2PMessage::Hello(hello)) => Ok(hello),
Ok(P2PMessage::Disconnect(reason)) => {
if matches!(reason, DisconnectReason::TooManyPeers) {
// Too many peers is a very common disconnect reason that spams the DEBUG logs
trace!(%reason, "Disconnected by peer during handshake");
} else {
debug!(%reason, "Disconnected by peer during handshake");
};
counter!("p2pstream.disconnected_errors").increment(1);
Err(P2PStreamError::HandshakeError(P2PHandshakeError::Disconnected(reason)))
}
Err(err) => {
debug!(%err, msg=%hex::encode(&first_message_bytes), "Failed to decode first message from peer");
Err(P2PStreamError::HandshakeError(err.into()))
}
Ok(msg) => {
debug!(?msg, "expected hello message but received another message");
Err(P2PStreamError::HandshakeError(P2PHandshakeError::NonHelloMessageInHandshake))
}
}?;
trace!(
hello=?their_hello,
"validating incoming p2p hello from peer"
);
if (hello.protocol_version as u8) != their_hello.protocol_version as u8 {
// send a disconnect message notifying the peer of the protocol version mismatch
self.send_disconnect(DisconnectReason::IncompatibleP2PProtocolVersion).await?;
return Err(P2PStreamError::MismatchedProtocolVersion(GotExpected {
got: their_hello.protocol_version,
expected: hello.protocol_version,
}))
}
// determine shared capabilities (currently returns only one capability)
let capability_res =
SharedCapabilities::try_new(hello.protocols, their_hello.capabilities.clone());
let shared_capability = match capability_res {
Err(err) => {
// we don't share any capabilities, send a disconnect message
self.send_disconnect(DisconnectReason::UselessPeer).await?;
Err(err)
}
Ok(cap) => Ok(cap),
}?;
let stream = P2PStream::new(self.inner, shared_capability);
Ok((stream, their_hello))
}
}
impl<S> UnauthedP2PStream<S>
where
S: Sink<Bytes, Error = io::Error> + Unpin,
{
/// Send a disconnect message during the handshake. This is sent without snappy compression.
pub async fn send_disconnect(
&mut self,
reason: DisconnectReason,
) -> Result<(), P2PStreamError> {
trace!(
%reason,
"Sending disconnect message during the handshake",
);
self.inner
.send(Bytes::from(alloy_rlp::encode(P2PMessage::Disconnect(reason))))
.await
.map_err(P2PStreamError::Io)
}
}
impl<S> CanDisconnect<Bytes> for P2PStream<S>
where
S: Sink<Bytes, Error = io::Error> + Unpin + Send + Sync,
{
async fn disconnect(&mut self, reason: DisconnectReason) -> Result<(), P2PStreamError> {
self.disconnect(reason).await
}
}
/// A P2PStream wraps over any `Stream` that yields bytes and makes it compatible with `p2p`
/// protocol messages.
///
/// This stream supports multiple shared capabilities, that were negotiated during the handshake.
///
/// ### Message-ID based multiplexing
///
/// > Each capability is given as much of the message-ID space as it needs. All such capabilities
/// > must statically specify how many message IDs they require. On connection and reception of the
/// > Hello message, both peers have equivalent information about what capabilities they share
/// > (including versions) and are able to form consensus over the composition of message ID space.
///
/// > Message IDs are assumed to be compact from ID 0x10 onwards (0x00-0x0f is reserved for the
/// > "p2p" capability) and given to each shared (equal-version, equal-name) capability in
/// > alphabetic order. Capability names are case-sensitive. Capabilities which are not shared are
/// > ignored. If multiple versions are shared of the same (equal name) capability, the numerically
/// > highest wins, others are ignored.
///
/// See also <https://github.com/ethereum/devp2p/blob/master/rlpx.md#message-id-based-multiplexing>
///
/// This stream emits _non-empty_ Bytes that start with the normalized message id, so that the first
/// byte of each message starts from 0. If this stream only supports a single capability, for
/// example `eth` then the first byte of each message will match
/// [EthMessageID](reth_eth_wire_types::message::EthMessageID).
#[pin_project]
#[derive(Debug)]
pub struct P2PStream<S> {
#[pin]
inner: S,
/// The snappy encoder used for compressing outgoing messages
encoder: snap::raw::Encoder,
/// The snappy decoder used for decompressing incoming messages
decoder: snap::raw::Decoder,
/// The state machine used for keeping track of the peer's ping status.
pinger: Pinger,
/// The supported capability for this stream.
shared_capabilities: SharedCapabilities,
/// Outgoing messages buffered for sending to the underlying stream.
outgoing_messages: VecDeque<Bytes>,
/// Maximum number of messages that we can buffer here before the [Sink] impl returns
/// [`Poll::Pending`].
outgoing_message_buffer_capacity: usize,
/// Whether this stream is currently in the process of disconnecting by sending a disconnect
/// message.
disconnecting: bool,
}
impl<S> P2PStream<S> {
/// Create a new [`P2PStream`] from the provided stream.
/// New [`P2PStream`]s are assumed to have completed the `p2p` handshake successfully and are
/// ready to send and receive subprotocol messages.
pub fn new(inner: S, shared_capabilities: SharedCapabilities) -> Self {
Self {
inner,
encoder: snap::raw::Encoder::new(),
decoder: snap::raw::Decoder::new(),
pinger: Pinger::new(PING_INTERVAL, PING_TIMEOUT),
shared_capabilities,
outgoing_messages: VecDeque::new(),
outgoing_message_buffer_capacity: MAX_P2P_CAPACITY,
disconnecting: false,
}
}
/// Returns a reference to the inner stream.
pub const fn inner(&self) -> &S {
&self.inner
}
/// Sets a custom outgoing message buffer capacity.
///
/// # Panics
///
/// If the provided capacity is `0`.
pub fn set_outgoing_message_buffer_capacity(&mut self, capacity: usize) {
self.outgoing_message_buffer_capacity = capacity;
}
/// Returns the shared capabilities for this stream.
///
/// This includes all the shared capabilities that were negotiated during the handshake and
/// their offsets based on the number of messages of each capability.
pub const fn shared_capabilities(&self) -> &SharedCapabilities {
&self.shared_capabilities
}
/// Returns `true` if the stream has outgoing capacity.
fn has_outgoing_capacity(&self) -> bool {
self.outgoing_messages.len() < self.outgoing_message_buffer_capacity
}
/// Queues in a _snappy_ encoded [`P2PMessage::Pong`] message.
fn send_pong(&mut self) {
self.outgoing_messages.push_back(Bytes::from(alloy_rlp::encode(P2PMessage::Pong)));
}
/// Queues in a _snappy_ encoded [`P2PMessage::Ping`] message.
pub fn send_ping(&mut self) {
self.outgoing_messages.push_back(Bytes::from(alloy_rlp::encode(P2PMessage::Ping)));
}
}
/// Gracefully disconnects the connection by sending a disconnect message and stop reading new
/// messages.
pub trait DisconnectP2P {
/// Starts to gracefully disconnect.
fn start_disconnect(&mut self, reason: DisconnectReason) -> Result<(), P2PStreamError>;
/// Returns `true` if the connection is about to disconnect.
fn is_disconnecting(&self) -> bool;
}
impl<S> DisconnectP2P for P2PStream<S> {
/// Starts to gracefully disconnect the connection by sending a Disconnect message and stop
/// reading new messages.
///
/// Once disconnect process has started, the [`Stream`] will terminate immediately.
///
/// # Errors
///
/// Returns an error only if the message fails to compress.
fn start_disconnect(&mut self, reason: DisconnectReason) -> Result<(), P2PStreamError> {
// clear any buffered messages and queue in
self.outgoing_messages.clear();
let disconnect = P2PMessage::Disconnect(reason);
let mut buf = Vec::with_capacity(disconnect.length());
disconnect.encode(&mut buf);
let mut compressed = vec![0u8; 1 + snap::raw::max_compress_len(buf.len() - 1)];
let compressed_size =
self.encoder.compress(&buf[1..], &mut compressed[1..]).map_err(|err| {
debug!(
%err,
msg=%hex::encode(&buf[1..]),
"error compressing disconnect"
);
err
})?;
// truncate the compressed buffer to the actual compressed size (plus one for the message
// id)
compressed.truncate(compressed_size + 1);
// we do not add the capability offset because the disconnect message is a `p2p` reserved
// message
compressed[0] = buf[0];
self.outgoing_messages.push_back(compressed.into());
self.disconnecting = true;
Ok(())
}
fn is_disconnecting(&self) -> bool {
self.disconnecting
}
}
impl<S> P2PStream<S>
where
S: Sink<Bytes, Error = io::Error> + Unpin + Send,
{
/// Disconnects the connection by sending a disconnect message.
///
/// This future resolves once the disconnect message has been sent and the stream has been
/// closed.
pub async fn disconnect(&mut self, reason: DisconnectReason) -> Result<(), P2PStreamError> {
self.start_disconnect(reason)?;
self.close().await
}
}
// S must also be `Sink` because we need to be able to respond with ping messages to follow the
// protocol
impl<S> Stream for P2PStream<S>
where
S: Stream<Item = io::Result<BytesMut>> + Sink<Bytes, Error = io::Error> + Unpin,
{
type Item = Result<BytesMut, P2PStreamError>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let this = self.get_mut();
if this.disconnecting {
// if disconnecting, stop reading messages
return Poll::Ready(None)
}
// we should loop here to ensure we don't return Poll::Pending if we have a message to
// return behind any pings we need to respond to
while let Poll::Ready(res) = this.inner.poll_next_unpin(cx) {
let bytes = match res {
Some(Ok(bytes)) => bytes,
Some(Err(err)) => return Poll::Ready(Some(Err(err.into()))),
None => return Poll::Ready(None),
};
if bytes.is_empty() {
// empty messages are not allowed
return Poll::Ready(Some(Err(P2PStreamError::EmptyProtocolMessage)))
}
// first decode disconnect reasons, because they can be encoded in a variety of forms
// over the wire, in both snappy compressed and uncompressed forms.
//
// see: [crate::disconnect::tests::test_decode_known_reasons]
let id = bytes[0];
if id == P2PMessageID::Disconnect as u8 {
// We can't handle the error here because disconnect reasons are encoded as both:
// * snappy compressed, AND
// * uncompressed
// over the network.
//
// If the decoding succeeds, we already checked the id and know this is a
// disconnect message, so we can return with the reason.
//
// If the decoding fails, we continue, and will attempt to decode it again if the
// message is snappy compressed. Failure handling in that step is the primary point
// where an error is returned if the disconnect reason is malformed.
if let Ok(reason) = DisconnectReason::decode(&mut &bytes[1..]) {
return Poll::Ready(Some(Err(P2PStreamError::Disconnected(reason))))
}
}
// first check that the compressed message length does not exceed the max
// payload size
let decompressed_len = snap::raw::decompress_len(&bytes[1..])?;
if decompressed_len > MAX_PAYLOAD_SIZE {
return Poll::Ready(Some(Err(P2PStreamError::MessageTooBig {
message_size: decompressed_len,
max_size: MAX_PAYLOAD_SIZE,
})))
}
// create a buffer to hold the decompressed message, adding a byte to the length for
// the message ID byte, which is the first byte in this buffer
let mut decompress_buf = BytesMut::zeroed(decompressed_len + 1);
// each message following a successful handshake is compressed with snappy, so we need
// to decompress the message before we can decode it.
this.decoder.decompress(&bytes[1..], &mut decompress_buf[1..]).map_err(|err| {
debug!(
%err,
msg=%hex::encode(&bytes[1..]),
"error decompressing p2p message"
);
err
})?;
match id {
_ if id == P2PMessageID::Ping as u8 => {
trace!("Received Ping, Sending Pong");
this.send_pong();
// This is required because the `Sink` may not be polled externally, and if
// that happens, the pong will never be sent.
cx.waker().wake_by_ref();
}
_ if id == P2PMessageID::Hello as u8 => {
// we have received a hello message outside of the handshake, so we will return
// an error
return Poll::Ready(Some(Err(P2PStreamError::HandshakeError(
P2PHandshakeError::HelloNotInHandshake,
))))
}
_ if id == P2PMessageID::Pong as u8 => {
// if we were waiting for a pong, this will reset the pinger state
this.pinger.on_pong()?
}
_ if id == P2PMessageID::Disconnect as u8 => {
// At this point, the `decompress_buf` contains the snappy decompressed
// disconnect message.
//
// It's possible we already tried to RLP decode this, but it was snappy
// compressed, so we need to RLP decode it again.
let reason = DisconnectReason::decode(&mut &decompress_buf[1..]).inspect_err(|err| {
debug!(
%err, msg=%hex::encode(&decompress_buf[1..]), "Failed to decode disconnect message from peer"
);
})?;
return Poll::Ready(Some(Err(P2PStreamError::Disconnected(reason))))
}
_ if id > MAX_P2P_MESSAGE_ID && id <= MAX_RESERVED_MESSAGE_ID => {
// we have received an unknown reserved message
return Poll::Ready(Some(Err(P2PStreamError::UnknownReservedMessageId(id))))
}
_ => {
// we have received a message that is outside the `p2p` reserved message space,
// so it is a subprotocol message.
// Peers must be able to identify messages meant for different subprotocols
// using a single message ID byte, and those messages must be distinct from the
// lower-level `p2p` messages.
//
// To ensure that messages for subprotocols are distinct from messages meant
// for the `p2p` capability, message IDs 0x00 - 0x0f are reserved for `p2p`
// messages, so subprotocol messages must have an ID of 0x10 or higher.
//
// To ensure that messages for two different capabilities are distinct from
// each other, all shared capabilities are first ordered lexicographically.
// Message IDs are then reserved in this order, starting at 0x10, reserving a
// message ID for each message the capability supports.
//
// For example, if the shared capabilities are `eth/67` (containing 10
// messages), and "qrs/65" (containing 8 messages):
//
// * The special case of `p2p`: `p2p` is reserved message IDs 0x00 - 0x0f.
// * `eth/67` is reserved message IDs 0x10 - 0x19.
// * `qrs/65` is reserved message IDs 0x1a - 0x21.
//
decompress_buf[0] = bytes[0] - MAX_RESERVED_MESSAGE_ID - 1;
return Poll::Ready(Some(Ok(decompress_buf)))
}
}
}
Poll::Pending
}
}
impl<S> Sink<Bytes> for P2PStream<S>
where
S: Sink<Bytes, Error = io::Error> + Unpin,
{
type Error = P2PStreamError;
fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
let mut this = self.as_mut();
// poll the pinger to determine if we should send a ping
match this.pinger.poll_ping(cx) {
Poll::Pending => {}
Poll::Ready(Ok(PingerEvent::Ping)) => {
this.send_ping();
}
_ => {
// encode the disconnect message
this.start_disconnect(DisconnectReason::PingTimeout)?;
// End the stream after ping related error
return Poll::Ready(Ok(()))
}
}
match this.inner.poll_ready_unpin(cx) {
Poll::Pending => {}
Poll::Ready(Err(err)) => return Poll::Ready(Err(P2PStreamError::Io(err))),
Poll::Ready(Ok(())) => {
let flushed = this.poll_flush(cx);
if flushed.is_ready() {
return flushed
}
}
}
if self.has_outgoing_capacity() {
// still has capacity
Poll::Ready(Ok(()))
} else {
Poll::Pending
}
}
fn start_send(self: Pin<&mut Self>, item: Bytes) -> Result<(), Self::Error> {
if item.len() > MAX_PAYLOAD_SIZE {
return Err(P2PStreamError::MessageTooBig {
message_size: item.len(),
max_size: MAX_PAYLOAD_SIZE,
})
}
if item.is_empty() {
// empty messages are not allowed
return Err(P2PStreamError::EmptyProtocolMessage)
}
// ensure we have free capacity
if !self.has_outgoing_capacity() {
return Err(P2PStreamError::SendBufferFull)
}
let this = self.project();
let mut compressed = BytesMut::zeroed(1 + snap::raw::max_compress_len(item.len() - 1));
let compressed_size =
this.encoder.compress(&item[1..], &mut compressed[1..]).map_err(|err| {
debug!(
%err,
msg=%hex::encode(&item[1..]),
"error compressing p2p message"
);
err
})?;
// truncate the compressed buffer to the actual compressed size (plus one for the message
// id)
compressed.truncate(compressed_size + 1);
// all messages sent in this stream are subprotocol messages, so we need to switch the
// message id based on the offset
compressed[0] = item[0] + MAX_RESERVED_MESSAGE_ID + 1;
this.outgoing_messages.push_back(compressed.freeze());
Ok(())
}
/// Returns `Poll::Ready(Ok(()))` when no buffered items remain.
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
let mut this = self.project();
let poll_res = loop {
match this.inner.as_mut().poll_ready(cx) {
Poll::Pending => break Poll::Pending,
Poll::Ready(Err(err)) => break Poll::Ready(Err(err.into())),
Poll::Ready(Ok(())) => {
let Some(message) = this.outgoing_messages.pop_front() else {
break Poll::Ready(Ok(()))
};
if let Err(err) = this.inner.as_mut().start_send(message) {
break Poll::Ready(Err(err.into()))
}
}
}
};
ready!(this.inner.as_mut().poll_flush(cx))?;
poll_res
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
ready!(self.as_mut().poll_flush(cx))?;
ready!(self.project().inner.poll_close(cx))?;
Poll::Ready(Ok(()))
}
}
/// This represents only the reserved `p2p` subprotocol messages.
#[derive(Debug, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[cfg_attr(any(test, feature = "arbitrary"), derive(arbitrary::Arbitrary))]
#[add_arbitrary_tests(rlp)]
pub enum P2PMessage {
/// The first packet sent over the connection, and sent once by both sides.
Hello(HelloMessage),
/// Inform the peer that a disconnection is imminent; if received, a peer should disconnect
/// immediately.
Disconnect(DisconnectReason),
/// Requests an immediate reply of [`P2PMessage::Pong`] from the peer.
Ping,
/// Reply to the peer's [`P2PMessage::Ping`] packet.
Pong,
}
impl P2PMessage {
/// Gets the [`P2PMessageID`] for the given message.
pub const fn message_id(&self) -> P2PMessageID {
match self {
Self::Hello(_) => P2PMessageID::Hello,
Self::Disconnect(_) => P2PMessageID::Disconnect,
Self::Ping => P2PMessageID::Ping,
Self::Pong => P2PMessageID::Pong,
}
}
}
impl Encodable for P2PMessage {
/// The [`Encodable`] implementation for [`P2PMessage::Ping`] and [`P2PMessage::Pong`] encodes
/// the message as RLP, and prepends a snappy header to the RLP bytes for all variants except
/// the [`P2PMessage::Hello`] variant, because the hello message is never compressed in the
/// `p2p` subprotocol.
fn encode(&self, out: &mut dyn BufMut) {
(self.message_id() as u8).encode(out);
match self {
Self::Hello(msg) => msg.encode(out),
Self::Disconnect(msg) => msg.encode(out),
Self::Ping => {
// Ping payload is _always_ snappy encoded
out.put_u8(0x01);
out.put_u8(0x00);
out.put_u8(EMPTY_LIST_CODE);
}
Self::Pong => {
// Pong payload is _always_ snappy encoded
out.put_u8(0x01);
out.put_u8(0x00);
out.put_u8(EMPTY_LIST_CODE);
}
}
}
fn length(&self) -> usize {
let payload_len = match self {
Self::Hello(msg) => msg.length(),
Self::Disconnect(msg) => msg.length(),
// id + snappy encoded payload
Self::Ping | Self::Pong => 3, // len([0x01, 0x00, 0xc0]) = 3
};
payload_len + 1 // (1 for length of p2p message id)
}
}
impl Decodable for P2PMessage {
/// The [`Decodable`] implementation for [`P2PMessage`] assumes that each of the message
/// variants are snappy compressed, except for the [`P2PMessage::Hello`] variant since the
/// hello message is never compressed in the `p2p` subprotocol.
///
/// The [`Decodable`] implementation for [`P2PMessage::Ping`] and [`P2PMessage::Pong`] expects
/// a snappy encoded payload, see [`Encodable`] implementation.
fn decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
/// Removes the snappy prefix from the Ping/Pong buffer
fn advance_snappy_ping_pong_payload(buf: &mut &[u8]) -> alloy_rlp::Result<()> {
if buf.len() < 3 {
return Err(RlpError::InputTooShort)
}
if buf[..3] != [0x01, 0x00, EMPTY_LIST_CODE] {
return Err(RlpError::Custom("expected snappy payload"))
}
buf.advance(3);
Ok(())
}
let message_id = u8::decode(&mut &buf[..])?;
let id = P2PMessageID::try_from(message_id)
.or(Err(RlpError::Custom("unknown p2p message id")))?;
buf.advance(1);
match id {
P2PMessageID::Hello => Ok(Self::Hello(HelloMessage::decode(buf)?)),
P2PMessageID::Disconnect => Ok(Self::Disconnect(DisconnectReason::decode(buf)?)),
P2PMessageID::Ping => {
advance_snappy_ping_pong_payload(buf)?;
Ok(Self::Ping)
}
P2PMessageID::Pong => {
advance_snappy_ping_pong_payload(buf)?;
Ok(Self::Pong)
}
}
}
}
/// Message IDs for `p2p` subprotocol messages.
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub enum P2PMessageID {
/// Message ID for the [`P2PMessage::Hello`] message.
Hello = 0x00,
/// Message ID for the [`P2PMessage::Disconnect`] message.
Disconnect = 0x01,
/// Message ID for the [`P2PMessage::Ping`] message.
Ping = 0x02,
/// Message ID for the [`P2PMessage::Pong`] message.
Pong = 0x03,
}
impl From<P2PMessage> for P2PMessageID {
fn from(msg: P2PMessage) -> Self {
match msg {
P2PMessage::Hello(_) => Self::Hello,
P2PMessage::Disconnect(_) => Self::Disconnect,
P2PMessage::Ping => Self::Ping,
P2PMessage::Pong => Self::Pong,
}
}
}
impl TryFrom<u8> for P2PMessageID {
type Error = P2PStreamError;
fn try_from(id: u8) -> Result<Self, Self::Error> {
match id {
0x00 => Ok(Self::Hello),
0x01 => Ok(Self::Disconnect),
0x02 => Ok(Self::Ping),
0x03 => Ok(Self::Pong),
_ => Err(P2PStreamError::UnknownReservedMessageId(id)),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{capability::SharedCapability, test_utils::eth_hello, EthVersion, ProtocolVersion};
use tokio::net::{TcpListener, TcpStream};
use tokio_util::codec::Decoder;
#[tokio::test]
async fn test_can_disconnect() {
reth_tracing::init_test_tracing();
let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
let local_addr = listener.local_addr().unwrap();
let expected_disconnect = DisconnectReason::UselessPeer;
let handle = tokio::spawn(async move {
// roughly based off of the design of tokio::net::TcpListener
let (incoming, _) = listener.accept().await.unwrap();
let stream = crate::PassthroughCodec::default().framed(incoming);
let (server_hello, _) = eth_hello();
let (mut p2p_stream, _) =
UnauthedP2PStream::new(stream).handshake(server_hello).await.unwrap();
p2p_stream.disconnect(expected_disconnect).await.unwrap();
});
let outgoing = TcpStream::connect(local_addr).await.unwrap();
let sink = crate::PassthroughCodec::default().framed(outgoing);
let (client_hello, _) = eth_hello();
let (mut p2p_stream, _) =
UnauthedP2PStream::new(sink).handshake(client_hello).await.unwrap();
let err = p2p_stream.next().await.unwrap().unwrap_err();
match err {
P2PStreamError::Disconnected(reason) => assert_eq!(reason, expected_disconnect),
e => panic!("unexpected err: {e}"),
}
handle.await.unwrap();
}
#[tokio::test]
async fn test_can_disconnect_weird_disconnect_encoding() {
reth_tracing::init_test_tracing();
let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
let local_addr = listener.local_addr().unwrap();
let expected_disconnect = DisconnectReason::SubprotocolSpecific;
let handle = tokio::spawn(async move {
// roughly based off of the design of tokio::net::TcpListener
let (incoming, _) = listener.accept().await.unwrap();
let stream = crate::PassthroughCodec::default().framed(incoming);
let (server_hello, _) = eth_hello();
let (mut p2p_stream, _) =
UnauthedP2PStream::new(stream).handshake(server_hello).await.unwrap();
// Unrolled `disconnect` method, without compression
p2p_stream.outgoing_messages.clear();
p2p_stream.outgoing_messages.push_back(Bytes::from(alloy_rlp::encode(
P2PMessage::Disconnect(DisconnectReason::SubprotocolSpecific),
)));
p2p_stream.disconnecting = true;
p2p_stream.close().await.unwrap();
});
let outgoing = TcpStream::connect(local_addr).await.unwrap();
let sink = crate::PassthroughCodec::default().framed(outgoing);
let (client_hello, _) = eth_hello();
let (mut p2p_stream, _) =
UnauthedP2PStream::new(sink).handshake(client_hello).await.unwrap();
let err = p2p_stream.next().await.unwrap().unwrap_err();
match err {
P2PStreamError::Disconnected(reason) => assert_eq!(reason, expected_disconnect),
e => panic!("unexpected err: {e}"),
}
handle.await.unwrap();
}
#[tokio::test]
async fn test_handshake_passthrough() {
// create a p2p stream and server, then confirm that the two are authed
// create tcpstream
let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
let local_addr = listener.local_addr().unwrap();
let handle = tokio::spawn(async move {
// roughly based off of the design of tokio::net::TcpListener
let (incoming, _) = listener.accept().await.unwrap();
let stream = crate::PassthroughCodec::default().framed(incoming);
let (server_hello, _) = eth_hello();
let unauthed_stream = UnauthedP2PStream::new(stream);
let (p2p_stream, _) = unauthed_stream.handshake(server_hello).await.unwrap();
// ensure that the two share a single capability, eth67
assert_eq!(
*p2p_stream.shared_capabilities.iter_caps().next().unwrap(),
SharedCapability::Eth {
version: EthVersion::Eth67,
offset: MAX_RESERVED_MESSAGE_ID + 1
}
);
});
let outgoing = TcpStream::connect(local_addr).await.unwrap();
let sink = crate::PassthroughCodec::default().framed(outgoing);
let (client_hello, _) = eth_hello();
let unauthed_stream = UnauthedP2PStream::new(sink);
let (p2p_stream, _) = unauthed_stream.handshake(client_hello).await.unwrap();
// ensure that the two share a single capability, eth67
assert_eq!(
*p2p_stream.shared_capabilities.iter_caps().next().unwrap(),
SharedCapability::Eth {
version: EthVersion::Eth67,
offset: MAX_RESERVED_MESSAGE_ID + 1
}
);
// make sure the server receives the message and asserts before ending the test
handle.await.unwrap();
}
#[tokio::test]
async fn test_handshake_disconnect() {
// create a p2p stream and server, then confirm that the two are authed
// create tcpstream
let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
let local_addr = listener.local_addr().unwrap();
let handle = tokio::spawn(Box::pin(async move {
// roughly based off of the design of tokio::net::TcpListener
let (incoming, _) = listener.accept().await.unwrap();
let stream = crate::PassthroughCodec::default().framed(incoming);
let (server_hello, _) = eth_hello();
let unauthed_stream = UnauthedP2PStream::new(stream);
match unauthed_stream.handshake(server_hello.clone()).await {
Ok((_, hello)) => {
panic!("expected handshake to fail, instead got a successful Hello: {hello:?}")
}
Err(P2PStreamError::MismatchedProtocolVersion(GotExpected { got, expected })) => {
assert_ne!(expected, got);
assert_eq!(expected, server_hello.protocol_version);
}
Err(other_err) => {
panic!("expected mismatched protocol version error, got {other_err:?}")
}
}
}));
let outgoing = TcpStream::connect(local_addr).await.unwrap();
let sink = crate::PassthroughCodec::default().framed(outgoing);
let (mut client_hello, _) = eth_hello();
// modify the hello to include an incompatible p2p protocol version
client_hello.protocol_version = ProtocolVersion::V4;
let unauthed_stream = UnauthedP2PStream::new(sink);
match unauthed_stream.handshake(client_hello.clone()).await {
Ok((_, hello)) => {
panic!("expected handshake to fail, instead got a successful Hello: {hello:?}")
}
Err(P2PStreamError::MismatchedProtocolVersion(GotExpected { got, expected })) => {
assert_ne!(expected, got);
assert_eq!(expected, client_hello.protocol_version);
}
Err(other_err) => {
panic!("expected mismatched protocol version error, got {other_err:?}")
}
}
// make sure the server receives the message and asserts before ending the test
handle.await.unwrap();
}
#[test]
fn snappy_decode_encode_ping() {
let snappy_ping = b"\x02\x01\0\xc0";
let ping = P2PMessage::decode(&mut &snappy_ping[..]).unwrap();
assert!(matches!(ping, P2PMessage::Ping));
assert_eq!(alloy_rlp::encode(ping), &snappy_ping[..]);
}
#[test]
fn snappy_decode_encode_pong() {
let snappy_pong = b"\x03\x01\0\xc0";
let pong = P2PMessage::decode(&mut &snappy_pong[..]).unwrap();
assert!(matches!(pong, P2PMessage::Pong));
assert_eq!(alloy_rlp::encode(pong), &snappy_pong[..]);
}
}