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use std::{collections::HashMap, io::ErrorKind, net::SocketAddr, sync::Arc};
use util::{sync::RwLock, Conn, Error};
use async_trait::async_trait;
use tokio::sync::{watch, Mutex};
mod udp_mux_conn;
use udp_mux_conn::{UDPMuxConn, UDPMuxConnParams};
#[cfg(test)]
mod udp_mux_test;
mod socket_addr_ext;
use stun::{
attributes::ATTR_USERNAME,
message::{is_message as is_stun_message, Message as STUNMessage},
};
use crate::candidate::RECEIVE_MTU;
fn normalize_socket_addr(target: &SocketAddr, socket_addr: &SocketAddr) -> SocketAddr {
match (target, socket_addr) {
(SocketAddr::V4(target_ipv4), SocketAddr::V6(_)) => {
let ipv6_mapped = target_ipv4.ip().to_ipv6_mapped();
SocketAddr::new(std::net::IpAddr::V6(ipv6_mapped), target_ipv4.port())
}
(_, _) => *target,
}
}
#[async_trait]
pub trait UDPMux {
async fn close(&self) -> Result<(), Error>;
async fn get_conn(self: Arc<Self>, ufrag: &str) -> Result<Arc<dyn Conn + Send + Sync>, Error>;
async fn remove_conn_by_ufrag(&self, ufrag: &str);
}
pub struct UDPMuxParams {
conn: Box<dyn Conn + Send + Sync>,
}
impl UDPMuxParams {
pub fn new<C>(conn: C) -> Self
where
C: Conn + Send + Sync + 'static,
{
Self {
conn: Box::new(conn),
}
}
}
pub struct UDPMuxDefault {
params: UDPMuxParams,
conns: Mutex<HashMap<String, UDPMuxConn>>,
address_map: RwLock<HashMap<SocketAddr, UDPMuxConn>>,
closed_watch_tx: Mutex<Option<watch::Sender<()>>>,
closed_watch_rx: watch::Receiver<()>,
}
impl UDPMuxDefault {
pub fn new(params: UDPMuxParams) -> Arc<Self> {
let (closed_watch_tx, closed_watch_rx) = watch::channel(());
let mux = Arc::new(Self {
params,
conns: Mutex::default(),
address_map: RwLock::default(),
closed_watch_tx: Mutex::new(Some(closed_watch_tx)),
closed_watch_rx: closed_watch_rx.clone(),
});
let cloned_mux = Arc::clone(&mux);
cloned_mux.start_conn_worker(closed_watch_rx);
mux
}
pub async fn is_closed(&self) -> bool {
self.closed_watch_tx.lock().await.is_none()
}
async fn send_to(&self, buf: &[u8], target: &SocketAddr) -> Result<usize, Error> {
self.params
.conn
.send_to(buf, *target)
.await
.map_err(Into::into)
}
async fn create_muxed_conn(self: &Arc<Self>, ufrag: &str) -> Result<UDPMuxConn, Error> {
let local_addr = self.params.conn.local_addr().await?;
let params = UDPMuxConnParams {
local_addr,
key: ufrag.into(),
udp_mux: Arc::clone(self),
};
Ok(UDPMuxConn::new(params))
}
async fn register_conn_for_address(&self, conn: &UDPMuxConn, addr: SocketAddr) {
if self.is_closed().await {
return;
}
let key = conn.key();
{
let mut addresses = self.address_map.write();
addresses
.entry(addr)
.and_modify(|e| {
if e.key() != key {
e.remove_address(&addr);
*e = conn.clone()
}
})
.or_insert_with(|| conn.clone());
}
log::debug!("Registered {} for {}", addr, key);
}
async fn conn_from_stun_message(&self, buffer: &[u8], addr: &SocketAddr) -> Option<UDPMuxConn> {
let (result, message) = {
let mut m = STUNMessage::new();
(m.unmarshal_binary(buffer), m)
};
match result {
Err(err) => {
log::warn!("Failed to handle decode ICE from {}: {}", addr, err);
None
}
Ok(_) => {
let (attr, found) = message.attributes.get(ATTR_USERNAME);
if !found {
log::warn!("No username attribute in STUN message from {}", &addr);
return None;
}
let s = match String::from_utf8(attr.value) {
Err(err) => {
log::warn!(
"Failed to decode USERNAME from STUN message as UTF-8: {}",
err
);
return None;
}
Ok(s) => s,
};
let conns = self.conns.lock().await;
let conn = s
.split(':')
.next()
.and_then(|ufrag| conns.get(ufrag))
.map(Clone::clone);
conn
}
}
}
fn start_conn_worker(self: Arc<Self>, mut closed_watch_rx: watch::Receiver<()>) {
tokio::spawn(async move {
let mut buffer = [0u8; RECEIVE_MTU];
loop {
let loop_self = Arc::clone(&self);
let conn = &loop_self.params.conn;
tokio::select! {
res = conn.recv_from(&mut buffer) => {
match res {
Ok((len, addr)) => {
let conn = {
let address_map = loop_self
.address_map
.read();
address_map.get(&addr).map(Clone::clone)
};
let conn = match conn {
None if is_stun_message(&buffer) => {
loop_self.conn_from_stun_message(&buffer, &addr).await
}
s @ Some(_) => s,
_ => None,
};
match conn {
None => {
log::trace!("Dropping packet from {}", &addr);
}
Some(conn) => {
if let Err(err) = conn.write_packet(&buffer[..len], addr).await {
log::error!("Failed to write packet: {}", err);
}
}
}
}
Err(Error::Io(err)) if err.0.kind() == ErrorKind::TimedOut => continue,
Err(err) => {
log::error!("Could not read udp packet: {}", err);
break;
}
}
}
_ = closed_watch_rx.changed() => {
return;
}
}
}
});
}
}
#[async_trait]
impl UDPMux for UDPMuxDefault {
async fn close(&self) -> Result<(), Error> {
if self.is_closed().await {
return Err(Error::ErrAlreadyClosed);
}
let mut closed_tx = self.closed_watch_tx.lock().await;
if let Some(tx) = closed_tx.take() {
let _ = tx.send(());
drop(closed_tx);
let old_conns = {
let mut conns = self.conns.lock().await;
std::mem::take(&mut (*conns))
};
for (_, conn) in old_conns.into_iter() {
conn.close();
}
{
let mut address_map = self.address_map.write();
let _ = std::mem::take(&mut (*address_map));
}
}
Ok(())
}
async fn get_conn(self: Arc<Self>, ufrag: &str) -> Result<Arc<dyn Conn + Send + Sync>, Error> {
if self.is_closed().await {
return Err(Error::ErrUseClosedNetworkConn);
}
{
let mut conns = self.conns.lock().await;
if let Some(conn) = conns.get(ufrag) {
return Ok(Arc::new(conn.clone()) as Arc<dyn Conn + Send + Sync>);
}
let muxed_conn = self.create_muxed_conn(ufrag).await?;
let mut close_rx = muxed_conn.close_rx();
let cloned_self = Arc::clone(&self);
let cloned_ufrag = ufrag.to_string();
tokio::spawn(async move {
let _ = close_rx.changed().await;
cloned_self.remove_conn_by_ufrag(&cloned_ufrag).await;
});
conns.insert(ufrag.into(), muxed_conn.clone());
Ok(Arc::new(muxed_conn) as Arc<dyn Conn + Send + Sync>)
}
}
async fn remove_conn_by_ufrag(&self, ufrag: &str) {
let removed_conn = {
let mut conns = self.conns.lock().await;
conns.remove(ufrag)
};
if let Some(conn) = removed_conn {
let mut address_map = self.address_map.write();
for address in conn.get_addresses() {
address_map.remove(&address);
}
}
}
}