Files
nanoreth/crates/net/downloaders/src/bodies/request.rs
Roman Krasiuk 5322877aed chore: bump alloy 0.11 (#14122)
Co-authored-by: Matthias Seitz <matthias.seitz@outlook.de>
2025-01-31 11:44:20 +00:00

317 lines
12 KiB
Rust

use crate::metrics::{BodyDownloaderMetrics, ResponseMetrics};
use alloy_consensus::BlockHeader;
use alloy_primitives::B256;
use futures::{Future, FutureExt};
use reth_consensus::{Consensus, ConsensusError};
use reth_network_p2p::{
bodies::{client::BodiesClient, response::BlockResponse},
error::{DownloadError, DownloadResult},
priority::Priority,
};
use reth_network_peers::{PeerId, WithPeerId};
use reth_primitives::{BlockBody, GotExpected, SealedBlock, SealedHeader};
use reth_primitives_traits::{Block, InMemorySize};
use std::{
collections::VecDeque,
mem,
pin::Pin,
sync::Arc,
task::{ready, Context, Poll},
};
/// Body request implemented as a [Future].
///
/// The future will poll the underlying request until fulfilled.
/// If the response arrived with insufficient number of bodies, the future
/// will issue another request until all bodies are collected.
///
/// It then proceeds to verify the downloaded bodies. In case of a validation error,
/// the future will start over.
///
/// The future will filter out any empty headers (see [`alloy_consensus::Header::is_empty`]) from
/// the request. If [`BodiesRequestFuture`] was initialized with all empty headers, no request will
/// be dispatched and they will be immediately returned upon polling.
///
/// NB: This assumes that peers respond with bodies in the order that they were requested.
/// This is a reasonable assumption to make as that's [what Geth
/// does](https://github.com/ethereum/go-ethereum/blob/f53ff0ff4a68ffc56004ab1d5cc244bcb64d3277/les/server_requests.go#L245).
/// All errors regarding the response cause the peer to get penalized, meaning that adversaries
/// that try to give us bodies that do not match the requested order are going to be penalized
/// and eventually disconnected.
pub(crate) struct BodiesRequestFuture<B: Block, C: BodiesClient<Body = B::Body>> {
client: Arc<C>,
consensus: Arc<dyn Consensus<B, Error = ConsensusError>>,
metrics: BodyDownloaderMetrics,
/// Metrics for individual responses. This can be used to observe how the size (in bytes) of
/// responses change while bodies are being downloaded.
response_metrics: ResponseMetrics,
// Headers to download. The collection is shrunk as responses are buffered.
pending_headers: VecDeque<SealedHeader<B::Header>>,
/// Internal buffer for all blocks
buffer: Vec<BlockResponse<B>>,
fut: Option<C::Output>,
/// Tracks how many bodies we requested in the last request.
last_request_len: Option<usize>,
}
impl<B, C> BodiesRequestFuture<B, C>
where
B: Block,
C: BodiesClient<Body = B::Body> + 'static,
{
/// Returns an empty future. Use [`BodiesRequestFuture::with_headers`] to set the request.
pub(crate) fn new(
client: Arc<C>,
consensus: Arc<dyn Consensus<B, Error = ConsensusError>>,
metrics: BodyDownloaderMetrics,
) -> Self {
Self {
client,
consensus,
metrics,
response_metrics: Default::default(),
pending_headers: Default::default(),
buffer: Default::default(),
last_request_len: None,
fut: None,
}
}
pub(crate) fn with_headers(mut self, headers: Vec<SealedHeader<B::Header>>) -> Self {
self.buffer.reserve_exact(headers.len());
self.pending_headers = VecDeque::from(headers);
// Submit the request only if there are any headers to download.
// Otherwise, the future will immediately be resolved.
if let Some(req) = self.next_request() {
self.submit_request(req, Priority::Normal);
}
self
}
fn on_error(&mut self, error: DownloadError, peer_id: Option<PeerId>) {
self.metrics.increment_errors(&error);
tracing::debug!(target: "downloaders::bodies", ?peer_id, %error, "Error requesting bodies");
if let Some(peer_id) = peer_id {
self.client.report_bad_message(peer_id);
}
self.submit_request(
self.next_request().expect("existing hashes to resubmit"),
Priority::High,
);
}
/// Retrieve header hashes for the next request.
fn next_request(&self) -> Option<Vec<B256>> {
let mut hashes =
self.pending_headers.iter().filter(|h| !h.is_empty()).map(|h| h.hash()).peekable();
hashes.peek().is_some().then(|| hashes.collect())
}
/// Submit the request with the given priority.
fn submit_request(&mut self, req: Vec<B256>, priority: Priority) {
tracing::trace!(target: "downloaders::bodies", request_len = req.len(), "Requesting bodies");
let client = Arc::clone(&self.client);
self.last_request_len = Some(req.len());
self.fut = Some(client.get_block_bodies_with_priority(req, priority));
}
/// Process block response.
/// Returns an error if the response is invalid.
fn on_block_response(&mut self, response: WithPeerId<Vec<B::Body>>) -> DownloadResult<()>
where
B::Body: InMemorySize,
{
let (peer_id, bodies) = response.split();
let request_len = self.last_request_len.unwrap_or_default();
let response_len = bodies.len();
tracing::trace!(target: "downloaders::bodies", request_len, response_len, ?peer_id, "Received bodies");
// Increment total downloaded metric
self.metrics.total_downloaded.increment(response_len as u64);
// TODO: Malicious peers often return a single block even if it does not exceed the soft
// response limit (2MB). This could be penalized by checking if this block and the
// next one exceed the soft response limit, if not then peer either does not have the next
// block or deliberately sent a single block.
if bodies.is_empty() {
return Err(DownloadError::EmptyResponse)
}
if response_len > request_len {
return Err(DownloadError::TooManyBodies(GotExpected {
got: response_len,
expected: request_len,
}))
}
// Buffer block responses
self.try_buffer_blocks(bodies)?;
// Submit next request if any
if let Some(req) = self.next_request() {
self.submit_request(req, Priority::High);
} else {
self.fut = None;
}
Ok(())
}
/// Attempt to buffer body responses. Returns an error if body response fails validation.
/// Every body preceding the failed one will be buffered.
///
/// This method removes headers from the internal collection.
/// If the response fails validation, then the header will be put back.
fn try_buffer_blocks(&mut self, bodies: Vec<C::Body>) -> DownloadResult<()>
where
C::Body: InMemorySize,
{
let bodies_capacity = bodies.capacity();
let bodies_len = bodies.len();
let mut bodies = bodies.into_iter().peekable();
let mut total_size = bodies_capacity * mem::size_of::<BlockBody>();
while bodies.peek().is_some() {
let next_header = match self.pending_headers.pop_front() {
Some(header) => header,
None => return Ok(()), // no more headers
};
if next_header.is_empty() {
// increment empty block body metric
total_size += mem::size_of::<C::Body>();
self.buffer.push(BlockResponse::Empty(next_header));
} else {
let next_body = bodies.next().unwrap();
// increment full block body metric
total_size += next_body.size();
let block = SealedBlock::from_sealed_parts(next_header, next_body);
if let Err(error) = self.consensus.validate_block_pre_execution(&block) {
// Body is invalid, put the header back and return an error
let hash = block.hash();
let number = block.number();
self.pending_headers.push_front(block.into_sealed_header());
return Err(DownloadError::BodyValidation {
hash,
number,
error: Box::new(error),
})
}
self.buffer.push(BlockResponse::Full(block));
}
}
// Increment per-response metric
self.response_metrics.response_size_bytes.set(total_size as f64);
self.response_metrics.response_length.set(bodies_len as f64);
Ok(())
}
}
impl<B, C> Future for BodiesRequestFuture<B, C>
where
B: Block + 'static,
C: BodiesClient<Body = B::Body> + 'static,
{
type Output = DownloadResult<Vec<BlockResponse<B>>>;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let this = self.get_mut();
loop {
if this.pending_headers.is_empty() {
return Poll::Ready(Ok(std::mem::take(&mut this.buffer)))
}
// Check if there is a pending requests. It might not exist if all
// headers are empty and there is nothing to download.
if let Some(fut) = this.fut.as_mut() {
match ready!(fut.poll_unpin(cx)) {
Ok(response) => {
let peer_id = response.peer_id();
if let Err(error) = this.on_block_response(response) {
this.on_error(error, Some(peer_id));
}
}
Err(error) => {
if error.is_channel_closed() {
return Poll::Ready(Err(error.into()))
}
this.on_error(error.into(), None);
}
}
}
// Buffer any empty headers
while this.pending_headers.front().is_some_and(|h| h.is_empty()) {
let header = this.pending_headers.pop_front().unwrap();
this.buffer.push(BlockResponse::Empty(header));
}
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{
bodies::test_utils::zip_blocks,
test_utils::{generate_bodies, TestBodiesClient},
};
use reth_consensus::test_utils::TestConsensus;
use reth_testing_utils::{generators, generators::random_header_range};
/// Check if future returns empty bodies without dispatching any requests.
#[tokio::test]
async fn request_returns_empty_bodies() {
let mut rng = generators::rng();
let headers = random_header_range(&mut rng, 0..20, B256::ZERO);
let client = Arc::new(TestBodiesClient::default());
let fut = BodiesRequestFuture::<reth_primitives::Block, _>::new(
client.clone(),
Arc::new(TestConsensus::default()),
BodyDownloaderMetrics::default(),
)
.with_headers(headers.clone());
assert_eq!(
fut.await.unwrap(),
headers.into_iter().map(BlockResponse::Empty).collect::<Vec<_>>()
);
assert_eq!(client.times_requested(), 0);
}
/// Check that the request future
#[tokio::test]
async fn request_submits_until_fulfilled() {
// Generate some random blocks
let (headers, mut bodies) = generate_bodies(0..=19);
let batch_size = 2;
let client = Arc::new(
TestBodiesClient::default().with_bodies(bodies.clone()).with_max_batch_size(batch_size),
);
let fut = BodiesRequestFuture::<reth_primitives::Block, _>::new(
client.clone(),
Arc::new(TestConsensus::default()),
BodyDownloaderMetrics::default(),
)
.with_headers(headers.clone());
assert_eq!(fut.await.unwrap(), zip_blocks(headers.iter(), &mut bodies));
assert_eq!(
client.times_requested(),
// div_ceild
(headers.into_iter().filter(|h| !h.is_empty()).count() as u64).div_ceil(2)
);
}
}