393 lines
13 KiB
Rust
393 lines
13 KiB
Rust
use std::{
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net::SocketAddr,
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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, ByteString};
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use clone_to_owned::CloneToOwned;
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use librqbit_core::{id20::Id20, lengths::ChunkInfo, peer_id::try_decode_peer_id};
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use parking_lot::RwLock;
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use peer_binary_protocol::{
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extended::{handshake::ExtendedHandshake, ExtendedMessage},
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serialize_piece_preamble, Handshake, Message, MessageBorrowed, MessageDeserializeError,
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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::trace;
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use crate::spawn_utils::BlockingSpawner;
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pub trait PeerConnectionHandler {
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fn on_connected(&self, _connection_time: Duration) {}
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fn get_have_bytes(&self) -> u64;
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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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fn on_received_message(&self, msg: Message<ByteBuf<'_>>) -> anyhow::Result<()>;
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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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}
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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,
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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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}
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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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macro_rules! read_one {
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($conn:ident, $read_buf:ident, $read_so_far:ident, $rwtimeout:ident) => {{
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let (extended, size) = loop {
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match MessageBorrowed::deserialize(&$read_buf[..$read_so_far]) {
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Ok((msg, size)) => break (msg, size),
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Err(MessageDeserializeError::NotEnoughData(d, _)) => {
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if $read_buf.len() < $read_so_far + d {
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$read_buf.reserve(d);
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$read_buf.resize($read_buf.capacity(), 0);
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}
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let size = with_timeout($rwtimeout, $conn.read(&mut $read_buf[$read_so_far..]))
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.await
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.context("error reading from peer")?;
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if size == 0 {
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anyhow::bail!("disconnected while reading, read so far: {}", $read_so_far)
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}
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$read_so_far += size;
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}
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Err(e) => return Err(e.into()),
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}
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};
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(extended, size)
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}};
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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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) -> 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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}
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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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// How many bytes into read buffer have we read already.
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read_so_far: usize,
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read_buf: Vec<u8>,
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handshake: Handshake<ByteString>,
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mut conn: tokio::net::TcpStream,
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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(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 h_supports_extended = handshake.supports_extended();
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self.handler.on_handshake(handshake)?;
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self.manage_peer(
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h_supports_extended,
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read_so_far,
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read_buf,
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write_buf,
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conn,
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outgoing_chan,
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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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) -> anyhow::Result<()> {
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use tokio::io::AsyncReadExt;
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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 conn = with_timeout(connect_timeout, tokio::net::TcpStream::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, 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 mut read_buf = vec![0u8; PIECE_MESSAGE_DEFAULT_LEN * 2];
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let mut read_so_far = with_timeout(rwtimeout, conn.read(&mut read_buf))
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.await
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.context("error reading handshake")?;
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if read_so_far == 0 {
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anyhow::bail!("bad handshake");
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}
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let (h, size) = Handshake::deserialize(&read_buf[..read_so_far])
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.map_err(|e| anyhow::anyhow!("error deserializing handshake: {:?}", e))?;
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let h_supports_extended = h.supports_extended();
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trace!("connected: id={:?}", try_decode_peer_id(Id20(h.peer_id)));
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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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if read_so_far > size {
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read_buf.copy_within(size..read_so_far, 0);
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}
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read_so_far -= size;
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self.manage_peer(
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h_supports_extended,
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read_so_far,
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read_buf,
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write_buf,
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conn,
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outgoing_chan,
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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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handshake_supports_extended: bool,
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// How many bytes into read_buf is there of peer-sent-data.
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mut read_so_far: usize,
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mut read_buf: Vec<u8>,
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mut write_buf: Vec<u8>,
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mut conn: tokio::net::TcpStream,
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mut outgoing_chan: tokio::sync::mpsc::UnboundedReceiver<WriterRequest>,
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) -> anyhow::Result<()> {
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use tokio::io::AsyncReadExt;
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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<ByteString>>> = 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 my_extended =
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Message::Extended(ExtendedMessage::Handshake(ExtendedHandshake::new()));
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trace!("sending extended handshake: {:?}", &my_extended);
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my_extended.serialize(&mut write_buf, &|| None).unwrap();
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with_timeout(rwtimeout, conn.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 (mut read_half, mut write_half) = tokio::io::split(conn);
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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.get_have_bytes() > 0 {
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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_half.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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loop {
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let req = match timeout(keep_alive_interval, outgoing_chan.recv()).await {
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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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let mut uploaded_add = None;
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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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.and_then(|e| e.ut_metadata())
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})?,
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WriterRequest::ReadChunkRequest(chunk) => {
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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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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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uploaded_add = Some(chunk.size);
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full_len
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}
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WriterRequest::Disconnect => {
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trace!("disconnect requested, closing writer");
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return Ok(());
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}
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};
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trace!("sending: {:?}, length={}", &req, len);
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with_timeout(rwtimeout, write_half.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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write_buf.clear();
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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, size) = read_one!(read_half, read_buf, read_so_far, rwtimeout);
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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());
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self.handler.on_extended_handshake(h)?;
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trace!("remembered extended handshake for future serializing");
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} else {
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self.handler
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.on_received_message(message)
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.context("error in handler.on_received_message()")?;
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}
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if read_so_far > size {
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read_buf.copy_within(size..read_so_far, 0);
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}
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read_so_far -= size;
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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 r = tokio::select! {
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r = reader => {
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trace!("reader is done, exiting");
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r
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}
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r = writer => {
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trace!("writer is done, exiting");
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r
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}
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};
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r
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}
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}
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