450 lines
16 KiB
Rust
450 lines
16 KiB
Rust
use std::{
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net::SocketAddr,
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sync::Arc,
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time::{Duration, Instant},
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};
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use anyhow::{bail, Context};
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use buffers::{ByteBuf, ByteBufOwned};
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use clone_to_owned::CloneToOwned;
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use librqbit_core::{
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hash_id::Id20,
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lengths::{ChunkInfo, ValidPieceIndex},
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peer_id::try_decode_peer_id,
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};
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use parking_lot::RwLock;
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use peer_binary_protocol::{
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extended::{handshake::ExtendedHandshake, ExtendedMessage, PeerIP},
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serialize_piece_preamble, Handshake, Message, MessageOwned, PIECE_MESSAGE_DEFAULT_LEN,
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};
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use serde::{Deserialize, Serialize};
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use serde_with::serde_as;
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use tokio::time::timeout;
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use tracing::{debug, trace};
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use crate::{read_buf::ReadBuf, spawn_utils::BlockingSpawner, stream_connect::StreamConnector};
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pub trait PeerConnectionHandler {
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fn on_connected(&self, _connection_time: Duration) {}
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fn should_send_bitfield(&self) -> bool;
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fn serialize_bitfield_message_to_buf(&self, buf: &mut Vec<u8>) -> anyhow::Result<usize>;
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fn on_handshake<B>(&self, handshake: Handshake<B>) -> anyhow::Result<()>;
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fn on_extended_handshake(
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&self,
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extended_handshake: &ExtendedHandshake<ByteBuf>,
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) -> anyhow::Result<()>;
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async fn on_received_message(&self, msg: Message<ByteBuf<'_>>) -> anyhow::Result<()>;
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fn should_transmit_have(&self, id: ValidPieceIndex) -> bool;
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fn on_uploaded_bytes(&self, bytes: u32);
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fn read_chunk(&self, chunk: &ChunkInfo, buf: &mut [u8]) -> anyhow::Result<()>;
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fn update_my_extended_handshake(
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&self,
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_handshake: &mut ExtendedHandshake<ByteBuf>,
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) -> anyhow::Result<()> {
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Ok(())
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}
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}
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#[derive(Debug)]
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pub enum WriterRequest {
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Message(MessageOwned),
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ReadChunkRequest(ChunkInfo),
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Disconnect(anyhow::Result<()>),
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}
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#[serde_as]
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#[derive(Default, Debug, Copy, Clone, Serialize, Deserialize)]
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pub struct PeerConnectionOptions {
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#[serde_as(as = "Option<serde_with::DurationSeconds>")]
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pub connect_timeout: Option<Duration>,
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#[serde_as(as = "Option<serde_with::DurationSeconds>")]
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pub read_write_timeout: Option<Duration>,
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#[serde_as(as = "Option<serde_with::DurationSeconds>")]
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pub keep_alive_interval: Option<Duration>,
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}
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pub(crate) struct PeerConnection<H> {
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handler: H,
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addr: SocketAddr,
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info_hash: Id20,
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peer_id: Id20,
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options: PeerConnectionOptions,
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spawner: BlockingSpawner,
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connector: Arc<StreamConnector>,
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}
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pub(crate) async fn with_timeout<T, E>(
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timeout_value: Duration,
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fut: impl std::future::Future<Output = Result<T, E>>,
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) -> anyhow::Result<T>
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where
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E: Into<anyhow::Error>,
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{
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match timeout(timeout_value, fut).await {
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Ok(v) => v.map_err(Into::into),
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Err(_) => anyhow::bail!("timeout at {timeout_value:?}"),
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}
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}
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struct ManagePeerArgs<R, W> {
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handshake_supports_extended: bool,
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read_buf: ReadBuf,
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write_buf: Vec<u8>,
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read: R,
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write: W,
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outgoing_chan: tokio::sync::mpsc::UnboundedReceiver<WriterRequest>,
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have_broadcast: tokio::sync::broadcast::Receiver<ValidPieceIndex>,
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}
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impl<H: PeerConnectionHandler> PeerConnection<H> {
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pub fn new(
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addr: SocketAddr,
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info_hash: Id20,
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peer_id: Id20,
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handler: H,
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options: Option<PeerConnectionOptions>,
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spawner: BlockingSpawner,
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connector: Arc<StreamConnector>,
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) -> Self {
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PeerConnection {
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handler,
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addr,
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info_hash,
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peer_id,
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spawner,
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options: options.unwrap_or_default(),
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connector,
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}
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}
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// By the time this is called:
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// read_buf should start with valuable data. The handshake should be removed from it.
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pub async fn manage_peer_incoming(
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&self,
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outgoing_chan: tokio::sync::mpsc::UnboundedReceiver<WriterRequest>,
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read_buf: ReadBuf,
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handshake: Handshake<ByteBufOwned>,
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mut conn: tokio::net::TcpStream,
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have_broadcast: tokio::sync::broadcast::Receiver<ValidPieceIndex>,
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) -> anyhow::Result<()> {
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use tokio::io::AsyncWriteExt;
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let rwtimeout = self
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.options
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.read_write_timeout
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.unwrap_or_else(|| Duration::from_secs(10));
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if handshake.info_hash != self.info_hash.0 {
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anyhow::bail!("wrong info hash");
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}
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if handshake.peer_id == self.peer_id.0 {
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bail!("looks like we are connecting to ourselves");
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}
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trace!(
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"incoming connection: id={:?}",
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try_decode_peer_id(Id20::new(handshake.peer_id))
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);
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let mut write_buf = Vec::<u8>::with_capacity(PIECE_MESSAGE_DEFAULT_LEN);
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let handshake = Handshake::new(self.info_hash, self.peer_id);
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handshake.serialize(&mut write_buf);
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with_timeout(rwtimeout, conn.write_all(&write_buf))
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.await
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.context("error writing handshake")?;
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write_buf.clear();
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let handshake_supports_extended = handshake.supports_extended();
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self.handler.on_handshake(handshake)?;
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let (read, write) = conn.into_split();
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self.manage_peer(ManagePeerArgs {
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handshake_supports_extended,
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read_buf,
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write_buf,
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read,
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write,
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outgoing_chan,
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have_broadcast,
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})
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.await
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}
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pub async fn manage_peer_outgoing(
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&self,
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outgoing_chan: tokio::sync::mpsc::UnboundedReceiver<WriterRequest>,
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have_broadcast: tokio::sync::broadcast::Receiver<ValidPieceIndex>,
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) -> anyhow::Result<()> {
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use tokio::io::AsyncWriteExt;
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let rwtimeout = self
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.options
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.read_write_timeout
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.unwrap_or_else(|| Duration::from_secs(10));
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let connect_timeout = self
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.options
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.connect_timeout
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.unwrap_or_else(|| Duration::from_secs(10));
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let now = Instant::now();
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let (mut read, mut write) =
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with_timeout(connect_timeout, self.connector.connect(self.addr))
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.await
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.context("error connecting")?;
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self.handler.on_connected(now.elapsed());
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let mut write_buf = Vec::<u8>::with_capacity(PIECE_MESSAGE_DEFAULT_LEN);
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let handshake = Handshake::new(self.info_hash, self.peer_id);
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handshake.serialize(&mut write_buf);
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with_timeout(rwtimeout, write.write_all(&write_buf))
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.await
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.context("error writing handshake")?;
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write_buf.clear();
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let mut read_buf = ReadBuf::new();
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let h = read_buf
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.read_handshake(&mut read, rwtimeout)
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.await
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.context("error reading handshake")?;
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let handshake_supports_extended = h.supports_extended();
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trace!(
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peer_id=?Id20::new(h.peer_id),
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decoded_id=?try_decode_peer_id(Id20::new(h.peer_id)),
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"connected",
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);
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if h.info_hash != self.info_hash.0 {
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anyhow::bail!("info hash does not match");
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}
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if h.peer_id == self.peer_id.0 {
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bail!("looks like we are connecting to ourselves");
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}
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self.handler.on_handshake(h)?;
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self.manage_peer(ManagePeerArgs {
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handshake_supports_extended,
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read_buf,
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write_buf,
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read,
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write,
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outgoing_chan,
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have_broadcast,
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})
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.await
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}
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async fn manage_peer(
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&self,
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args: ManagePeerArgs<
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impl tokio::io::AsyncRead + Send + Unpin,
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impl tokio::io::AsyncWrite + Send + Unpin,
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>,
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) -> anyhow::Result<()> {
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let ManagePeerArgs {
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handshake_supports_extended,
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mut read_buf,
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mut write_buf,
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mut read,
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mut write,
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mut outgoing_chan,
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mut have_broadcast,
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} = args;
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use tokio::io::AsyncWriteExt;
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let rwtimeout = self
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.options
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.read_write_timeout
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.unwrap_or_else(|| Duration::from_secs(10));
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let extended_handshake: RwLock<Option<ExtendedHandshake<ByteBufOwned>>> = RwLock::new(None);
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let extended_handshake_ref = &extended_handshake;
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let supports_extended = handshake_supports_extended;
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if supports_extended {
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let mut my_extended = ExtendedHandshake::new();
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my_extended.v = Some(ByteBuf(crate::client_name_and_version().as_bytes()));
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my_extended.yourip = Some(PeerIP(self.addr.ip()));
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self.handler
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.update_my_extended_handshake(&mut my_extended)?;
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let my_extended = Message::Extended(ExtendedMessage::Handshake(my_extended));
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trace!("sending extended handshake: {:?}", &my_extended);
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my_extended
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.serialize(&mut write_buf, &Default::default)
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.unwrap();
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with_timeout(rwtimeout, write.write_all(&write_buf))
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.await
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.context("error writing extended handshake")?;
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write_buf.clear();
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}
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let writer = async move {
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let keep_alive_interval = self
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.options
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.keep_alive_interval
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.unwrap_or_else(|| Duration::from_secs(120));
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if self.handler.should_send_bitfield() {
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let len = self
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.handler
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.serialize_bitfield_message_to_buf(&mut write_buf)?;
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with_timeout(rwtimeout, write.write_all(&write_buf[..len]))
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.await
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.context("error writing bitfield to peer")?;
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trace!("sent bitfield");
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}
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let len = MessageOwned::Unchoke.serialize(&mut write_buf, &Default::default)?;
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with_timeout(rwtimeout, write.write_all(&write_buf[..len]))
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.await
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.context("error writing unchoke")?;
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trace!("sent unchoke");
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let mut broadcast_closed = false;
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loop {
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let req = loop {
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break tokio::select! {
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r = have_broadcast.recv(), if !broadcast_closed => match r {
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Ok(id) => {
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if self.handler.should_transmit_have(id) {
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WriterRequest::Message(MessageOwned::Have(id.get()))
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} else {
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continue
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}
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},
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Err(tokio::sync::broadcast::error::RecvError::Closed) => {
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broadcast_closed = true;
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debug!("broadcast channel closed, will not poll it anymore");
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continue
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},
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_ => continue
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},
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r = timeout(keep_alive_interval, outgoing_chan.recv()) => match r {
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Ok(Some(msg)) => msg,
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Ok(None) => {
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anyhow::bail!("closing writer, channel closed");
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}
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Err(_) => WriterRequest::Message(MessageOwned::KeepAlive),
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}
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};
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};
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let mut uploaded_add = None;
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trace!("about to send: {:?}", &req);
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let len = match req {
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WriterRequest::Message(msg) => msg.serialize(&mut write_buf, &|| {
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extended_handshake_ref
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.read()
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.as_ref()
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.map(|e| e.peer_extended_messages())
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.unwrap_or_default()
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})?,
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WriterRequest::ReadChunkRequest(chunk) => {
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#[allow(unused_mut)]
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let mut skip_reading_for_e2e_tests = false;
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#[cfg(test)]
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{
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use tracing::warn;
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// This is poor-mans fault injection for running e2e tests.
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use crate::tests::test_util::TestPeerMetadata;
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let tpm = TestPeerMetadata::from_peer_id(self.peer_id);
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use rand::Rng;
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if rand::rng().random_bool(tpm.disconnect_probability()) {
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bail!("disconnecting, to simulate failure in tests");
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}
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#[allow(clippy::cast_possible_truncation)]
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let sleep_ms = (rand::rng().random::<f64>()
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* (tpm.max_random_sleep_ms as f64))
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as u64;
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tokio::time::sleep(Duration::from_millis(sleep_ms)).await;
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if rand::rng().random_bool(tpm.bad_data_probability()) {
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warn!("will NOT actually read the data to simulate a malicious peer that sends garbage");
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write_buf.fill(0);
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skip_reading_for_e2e_tests = true;
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}
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}
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// this whole section is an optimization
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write_buf.resize(PIECE_MESSAGE_DEFAULT_LEN, 0);
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let preamble_len = serialize_piece_preamble(&chunk, &mut write_buf);
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let full_len = preamble_len + chunk.size as usize;
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write_buf.resize(full_len, 0);
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if !skip_reading_for_e2e_tests {
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self.spawner
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.spawn_block_in_place(|| {
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self.handler
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.read_chunk(&chunk, &mut write_buf[preamble_len..])
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})
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.with_context(|| format!("error reading chunk {chunk:?}"))?;
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}
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uploaded_add = Some(chunk.size);
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full_len
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}
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WriterRequest::Disconnect(res) => {
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trace!("disconnect requested, closing writer");
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return res;
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}
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};
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with_timeout(rwtimeout, write.write_all(&write_buf[..len]))
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.await
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.context("error writing the message to peer")?;
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if let Some(uploaded_add) = uploaded_add {
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self.handler.on_uploaded_bytes(uploaded_add)
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}
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}
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// For type inference.
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#[allow(unreachable_code)]
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Ok::<_, anyhow::Error>(())
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};
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let reader = async move {
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loop {
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let message = read_buf
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.read_message(&mut read, rwtimeout)
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.await
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.context("error reading message")?;
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trace!("received: {:?}", &message);
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if let Message::Extended(ExtendedMessage::Handshake(h)) = &message {
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*extended_handshake_ref.write() = Some(h.clone_to_owned(None));
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self.handler.on_extended_handshake(h)?;
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} else {
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self.handler
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.on_received_message(message)
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.await
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.context("error in handler.on_received_message()")?;
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}
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}
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// For type inference.
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#[allow(unreachable_code)]
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Ok::<_, anyhow::Error>(())
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};
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tokio::select! {
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r = reader => {
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trace!(result=?r, "reader is done, exiting");
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r
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}
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r = writer => {
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trace!(result=?r, "writer is done, exiting");
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r
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}
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}
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}
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}
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