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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![allow(clippy::missing_errors_doc)] // Functions simply delegate to tokio and quinn-udp.
use std::{
cell::RefCell,
io::{self, IoSliceMut},
net::SocketAddr,
slice,
};
use neqo_common::{qdebug, qtrace, Datagram, IpTos};
use quinn_udp::{EcnCodepoint, RecvMeta, Transmit, UdpSocketState};
/// Socket receive buffer size.
///
/// Allows reading multiple datagrams in a single [`Socket::recv`] call.
//
// TODO: Experiment with different values across platforms.
const RECV_BUF_SIZE: usize = u16::MAX as usize;
std::thread_local! {
static RECV_BUF: RefCell<Vec<u8>> = RefCell::new(vec![0; RECV_BUF_SIZE]);
}
pub fn send_inner(
state: &UdpSocketState,
socket: quinn_udp::UdpSockRef<'_>,
d: &Datagram,
) -> io::Result<()> {
let transmit = Transmit {
destination: d.destination(),
ecn: EcnCodepoint::from_bits(Into::<u8>::into(d.tos())),
contents: d,
segment_size: None,
src_ip: None,
};
state.send(socket, &transmit)?;
qtrace!(
"sent {} bytes from {} to {}",
d.len(),
d.source(),
d.destination()
);
Ok(())
}
#[cfg(unix)]
use std::os::fd::AsFd as SocketRef;
#[cfg(windows)]
use std::os::windows::io::AsSocket as SocketRef;
pub fn recv_inner(
local_address: &SocketAddr,
state: &UdpSocketState,
socket: impl SocketRef,
) -> Result<Vec<Datagram>, io::Error> {
let dgrams = RECV_BUF.with_borrow_mut(|recv_buf| -> Result<Vec<Datagram>, io::Error> {
let mut meta;
loop {
meta = RecvMeta::default();
state.recv(
(&socket).into(),
&mut [IoSliceMut::new(recv_buf)],
slice::from_mut(&mut meta),
)?;
if meta.len == 0 || meta.stride == 0 {
qdebug!(
"ignoring datagram from {} to {} len {} stride {}",
meta.addr,
local_address,
meta.len,
meta.stride
);
continue;
}
break;
}
Ok(recv_buf[0..meta.len]
.chunks(meta.stride)
.map(|d| {
qtrace!(
"received {} bytes from {} to {}",
d.len(),
meta.addr,
local_address,
);
Datagram::new(
meta.addr,
*local_address,
meta.ecn.map(|n| IpTos::from(n as u8)).unwrap_or_default(),
d,
)
})
.collect())
})?;
qtrace!(
"received {} datagrams ({:?})",
dgrams.len(),
dgrams.iter().map(|d| d.len()).collect::<Vec<_>>(),
);
Ok(dgrams)
}
/// A wrapper around a UDP socket, sending and receiving [`Datagram`]s.
pub struct Socket<S> {
state: UdpSocketState,
inner: S,
}
impl<S: SocketRef> Socket<S> {
/// Create a new [`Socket`] given a raw file descriptor managed externally.
pub fn new(socket: S) -> Result<Self, io::Error> {
Ok(Self {
state: quinn_udp::UdpSocketState::new((&socket).into())?,
inner: socket,
})
}
/// Send a [`Datagram`] on the given [`Socket`].
pub fn send(&self, d: &Datagram) -> io::Result<()> {
send_inner(&self.state, (&self.inner).into(), d)
}
/// Receive a batch of [`Datagram`]s on the given [`Socket`], each
/// set with the provided local address.
pub fn recv(&self, local_address: &SocketAddr) -> Result<Vec<Datagram>, io::Error> {
recv_inner(local_address, &self.state, &self.inner)
}
}
#[cfg(test)]
mod tests {
use neqo_common::{IpTosDscp, IpTosEcn};
use super::*;
fn socket() -> Result<Socket<std::net::UdpSocket>, io::Error> {
let socket = Socket::new(std::net::UdpSocket::bind("127.0.0.1:0")?)?;
// Reverse non-blocking flag set by `UdpSocketState` to make the test non-racy.
socket.inner.set_nonblocking(false)?;
Ok(socket)
}
#[test]
fn ignore_empty_datagram() -> Result<(), io::Error> {
let sender = socket()?;
let receiver = Socket::new(std::net::UdpSocket::bind("127.0.0.1:0")?)?;
let receiver_addr: SocketAddr = "127.0.0.1:0".parse().unwrap();
let datagram = Datagram::new(
sender.inner.local_addr()?,
receiver.inner.local_addr()?,
IpTos::default(),
vec![],
);
sender.send(&datagram)?;
let res = receiver.recv(&receiver_addr);
assert_eq!(res.unwrap_err().kind(), std::io::ErrorKind::WouldBlock);
Ok(())
}
#[test]
fn datagram_tos() -> Result<(), io::Error> {
let sender = socket()?;
let receiver = socket()?;
let receiver_addr: SocketAddr = "127.0.0.1:0".parse().unwrap();
let datagram = Datagram::new(
sender.inner.local_addr()?,
receiver.inner.local_addr()?,
IpTos::from((IpTosDscp::Le, IpTosEcn::Ect1)),
b"Hello, world!".to_vec(),
);
sender.send(&datagram)?;
let received_datagram = receiver
.recv(&receiver_addr)
.expect("receive to succeed")
.into_iter()
.next()
.expect("receive to yield datagram");
// Assert that the ECN is correct.
assert_eq!(
IpTosEcn::from(datagram.tos()),
IpTosEcn::from(received_datagram.tos())
);
Ok(())
}
/// Expect [`Socket::recv`] to handle multiple [`Datagram`]s on GRO read.
#[test]
#[cfg_attr(not(any(target_os = "linux", target_os = "windows")), ignore)]
fn many_datagrams_through_gro() -> Result<(), io::Error> {
const SEGMENT_SIZE: usize = 128;
let sender = socket()?;
let receiver = socket()?;
let receiver_addr: SocketAddr = "127.0.0.1:0".parse().unwrap();
// `neqo_udp::Socket::send` does not yet
// `quinn_udp` directly.
let max_gso_segments = sender.state.max_gso_segments();
let msg = vec![0xAB; SEGMENT_SIZE * max_gso_segments];
let transmit = Transmit {
destination: receiver.inner.local_addr()?,
ecn: EcnCodepoint::from_bits(Into::<u8>::into(IpTos::from((
IpTosDscp::Le,
IpTosEcn::Ect1,
)))),
contents: &msg,
segment_size: Some(SEGMENT_SIZE),
src_ip: None,
};
sender.state.send((&sender.inner).into(), &transmit)?;
// Allow for one GSO sendmmsg to result in multiple GRO recvmmsg.
let mut num_received = 0;
while num_received < max_gso_segments {
receiver
.recv(&receiver_addr)
.expect("receive to succeed")
.into_iter()
.for_each(|d| {
assert_eq!(
SEGMENT_SIZE,
d.len(),
"Expect received datagrams to have same length as sent datagrams."
);
num_received += 1;
});
}
Ok(())
}
}