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use std::{
self,
net::{Ipv4Addr, SocketAddr, SocketAddrV4, ToSocketAddrs, UdpSocket},
thread::{sleep, yield_now},
time::{Duration, Instant},
};
use crossbeam_channel::{self, Receiver, Sender, TryRecvError};
use crate::{
config::Config,
error::Result,
net::{
events::SocketEvent, ConnectionManager, DatagramSocket, LinkConditioner, VirtualConnection,
},
packet::Packet,
};
// Wraps `LinkConditioner` and `UdpSocket` together. LinkConditioner is enabled when building with a "tester" feature.
#[derive(Debug)]
struct SocketWithConditioner {
is_blocking_mode: bool,
socket: UdpSocket,
link_conditioner: Option<LinkConditioner>,
}
impl SocketWithConditioner {
pub fn new(socket: UdpSocket, is_blocking_mode: bool) -> Result<Self> {
socket.set_nonblocking(!is_blocking_mode)?;
Ok(SocketWithConditioner {
is_blocking_mode,
socket,
link_conditioner: None,
})
}
#[cfg(feature = "tester")]
pub fn set_link_conditioner(&mut self, link_conditioner: Option<LinkConditioner>) {
self.link_conditioner = link_conditioner;
}
}
/// Provides a `DatagramSocket` implementation for `SocketWithConditioner`
impl DatagramSocket for SocketWithConditioner {
// Determinate whether packet will be sent or not based on `LinkConditioner` if enabled.
fn send_packet(&mut self, addr: &SocketAddr, payload: &[u8]) -> std::io::Result<usize> {
if cfg!(feature = "tester") {
if let Some(ref mut link) = &mut self.link_conditioner {
if !link.should_send() {
return Ok(0);
}
}
}
self.socket.send_to(payload, addr)
}
/// Receives a single packet from UDP socket.
fn receive_packet<'a>(
&mut self,
buffer: &'a mut [u8],
) -> std::io::Result<(&'a [u8], SocketAddr)> {
self.socket
.recv_from(buffer)
.map(move |(recv_len, address)| (&buffer[..recv_len], address))
}
/// Returns the socket address that this socket was created from.
fn local_addr(&self) -> std::io::Result<SocketAddr> {
self.socket.local_addr()
}
/// Returns whether socket operates in blocking or non-blocking mode.
fn is_blocking_mode(&self) -> bool {
self.is_blocking_mode
}
}
/// A reliable UDP socket implementation with configurable reliability and ordering guarantees.
#[derive(Debug)]
pub struct Socket {
handler: ConnectionManager<SocketWithConditioner, VirtualConnection>,
}
impl Socket {
/// Binds to the socket and then sets up `ActiveConnections` to manage the "connections".
/// Because UDP connections are not persistent, we can only infer the status of the remote
/// endpoint by looking to see if they are still sending packets or not
pub fn bind<A: ToSocketAddrs>(addresses: A) -> Result<Self> {
Self::bind_with_config(addresses, Config::default())
}
/// Binds to any local port on the system, if available
pub fn bind_any() -> Result<Self> {
Self::bind_any_with_config(Config::default())
}
/// Binds to any local port on the system, if available, with a given config
pub fn bind_any_with_config(config: Config) -> Result<Self> {
let loopback = Ipv4Addr::new(127, 0, 0, 1);
let address = SocketAddrV4::new(loopback, 0);
let socket = UdpSocket::bind(address)?;
Self::bind_internal(socket, config)
}
/// Binds to the socket and then sets up `ActiveConnections` to manage the "connections".
/// Because UDP connections are not persistent, we can only infer the status of the remote
/// endpoint by looking to see if they are still sending packets or not
///
/// This function allows you to configure laminar with the passed configuration.
pub fn bind_with_config<A: ToSocketAddrs>(addresses: A, config: Config) -> Result<Self> {
let socket = UdpSocket::bind(addresses)?;
Self::bind_internal(socket, config)
}
fn bind_internal(socket: UdpSocket, config: Config) -> Result<Self> {
Ok(Socket {
handler: ConnectionManager::new(
SocketWithConditioner::new(socket, config.blocking_mode)?,
config,
),
})
}
/// Returns a handle to the packet sender which provides a thread-safe way to enqueue packets
/// to be processed. This should be used when the socket is busy running its polling loop in a
/// separate thread.
pub fn get_packet_sender(&self) -> Sender<Packet> {
self.handler.event_sender().clone()
}
/// Returns a handle to the event receiver which provides a thread-safe way to retrieve events
/// from the socket. This should be used when the socket is busy running its polling loop in
/// a separate thread.
pub fn get_event_receiver(&self) -> Receiver<SocketEvent> {
self.handler.event_receiver().clone()
}
/// Sends a single packet
pub fn send(&mut self, packet: Packet) -> Result<()> {
self.handler
.event_sender()
.send(packet)
.expect("Receiver must exists.");
Ok(())
}
/// Receives a single packet
pub fn recv(&mut self) -> Option<SocketEvent> {
match self.handler.event_receiver().try_recv() {
Ok(pkt) => Some(pkt),
Err(TryRecvError::Empty) => None,
Err(TryRecvError::Disconnected) => panic!["This can never happen"],
}
}
/// Runs the polling loop with the default '1ms' sleep duration. This should run in a spawned thread
/// since calls to `self.manual_poll` are blocking.
pub fn start_polling(&mut self) {
self.start_polling_with_duration(Some(Duration::from_millis(1)))
}
/// Runs the polling loop with a specified sleep duration. This should run in a spawned thread
/// since calls to `self.manual_poll` are blocking.
pub fn start_polling_with_duration(&mut self, sleep_duration: Option<Duration>) {
// nothing should break out of this loop!
loop {
self.manual_poll(Instant::now());
match sleep_duration {
None => yield_now(),
Some(duration) => sleep(duration),
};
}
}
/// Processes any inbound/outbound packets and handle idle clients
pub fn manual_poll(&mut self, time: Instant) {
self.handler.manual_poll(time);
}
/// Returns the local socket address
pub fn local_addr(&self) -> Result<SocketAddr> {
Ok(self.handler.socket().local_addr()?)
}
/// Sets the link conditioner for this socket. See [LinkConditioner] for further details.
#[cfg(feature = "tester")]
pub fn set_link_conditioner(&mut self, link_conditioner: Option<LinkConditioner>) {
self.handler
.socket_mut()
.set_link_conditioner(link_conditioner);
}
}