fix error on setting dual-stack socket

tuic-client/src/connection.rs

@@ -88,13 +88,20 @@ impl Endpoint {
 
         config.transport_config(Arc::new(tp_cfg));
 
-        let socket = UdpSocket::bind(SocketAddr::from(([0, 0, 0, 0], 0)))?;
+        // Try to create an IPv4 socket as the placeholder first, if it fails, try IPv6.
+        let socket = UdpSocket::bind(SocketAddr::from((Ipv4Addr::UNSPECIFIED, 0)))
+            .or_else(|err| {
+                UdpSocket::bind(SocketAddr::from((Ipv6Addr::UNSPECIFIED, 0))).map_err(|_| err)
+            })
+            .map_err(|err| Error::Socket("failed to create endpoint UDP socket", err))?;
+
         let mut ep = QuinnEndpoint::new(
             EndpointConfig::default(),
             None,
             socket,
             Arc::new(TokioRuntime),
         )?;
+
         ep.set_default_client_config(config);
 
         let ep = Self {
@@ -139,7 +146,12 @@ impl Endpoint {
                     SocketAddr::from((Ipv6Addr::UNSPECIFIED, 0))
                 };
 
-                ep.rebind(UdpSocket::bind(bind_addr)?)?;
+                ep.rebind(
+                    UdpSocket::bind(bind_addr).map_err(|err| {
+                        Error::Socket("failed to create endpoint UDP socket", err)
+                    })?,
+                )
+                .map_err(|err| Error::Socket("failed to rebind endpoint UDP socket", err))?;
             }
 
             let conn = ep.connect(addr, server_name)?;

tuic-client/src/main.rs

@@ -68,6 +68,8 @@ pub enum Error {
     LoadNativeCerts(IoError),
     #[error(transparent)]
     Rustls(#[from] RustlsError),
+    #[error("{0}: {1}")]
+    Socket(&'static str, IoError),
     #[error("timeout establishing connection")]
     Timeout,
     #[error("cannot resolve the server name")]

tuic-client/src/socks5.rs

@@ -3,7 +3,7 @@ use bytes::Bytes;
 use once_cell::sync::OnceCell;
 use parking_lot::Mutex;
 use quinn::VarInt;
-use socket2::Socket;
+use socket2::{Domain, Protocol, SockAddr, Socket, Type};
 use socks5_proto::{Address, Reply};
 use socks5_server::{
     auth::{NoAuth, Password},
@@ -30,7 +30,6 @@ static SERVER: OnceCell<Server> = OnceCell::new();
 
 pub struct Server {
     inner: Socks5Server,
-    addr: SocketAddr,
     dual_stack: Option<bool>,
     max_pkt_size: usize,
     next_assoc_id: AtomicU16,
@@ -40,22 +39,38 @@ pub struct Server {
 impl Server {
     pub async fn set_config(cfg: Local) -> Result<(), Error> {
         let socket = {
-            let socket = Socket::from(TcpListener::bind(&cfg.server).await?.into_std()?);
+            let domain = match cfg.server {
+                SocketAddr::V4(_) => Domain::IPV4,
+                SocketAddr::V6(_) => Domain::IPV6,
+            };
+
+            let socket = Socket::new(domain, Type::STREAM, Some(Protocol::TCP))
+                .map_err(|err| Error::Socket("failed to create socks5 server socket", err))?;
 
             if let Some(dual_stack) = cfg.dual_stack {
-                if cfg.server.is_ipv4() && dual_stack {
+                socket.set_only_v6(!dual_stack).map_err(|err| {
-                    return Err(Error::from(IoError::new(
+                    Error::Socket("socks5 server dual-stack socket setting error", err)
-                        ErrorKind::Unsupported,
+                })?;
-                        "IPv4 socket cannot be dual stack",
-                    )));
-                }
-
-                socket.set_only_v6(!dual_stack)?;
             }
 
-            socket.set_reuse_address(true)?;
+            socket.set_reuse_address(true).map_err(|err| {
+                Error::Socket("failed to set socks5 server socket to reuse_address", err)
+            })?;
 
-            TcpListener::from_std(StdTcpListener::from(socket))?
+            socket.set_nonblocking(true).map_err(|err| {
+                Error::Socket("failed setting socks5 server socket as non-blocking", err)
+            })?;
+
+            socket
+                .bind(&SockAddr::from(cfg.server))
+                .map_err(|err| Error::Socket("failed to bind socks5 server socket", err))?;
+
+            socket
+                .listen(i32::MAX)
+                .map_err(|err| Error::Socket("failed to listen on socks5 server socket", err))?;
+
+            TcpListener::from_std(StdTcpListener::from(socket))
+                .map_err(|err| Error::Socket("failed to create socks5 server socket", err))?
         };
 
         let auth: Arc<dyn Auth + Send + Sync> = match (cfg.username, cfg.password) {
@@ -68,7 +83,6 @@ impl Server {
 
         let server = Self {
             inner: Socks5Server::new(socket, auth),
-            addr: cfg.server,
             dual_stack: cfg.dual_stack,
             max_pkt_size: cfg.max_packet_size,
             next_assoc_id: AtomicU16::new(0),
@@ -84,11 +98,10 @@ impl Server {
     }
 
     pub async fn start() {
-        let server = SERVER.get().unwrap();
+        log::warn!("[socks5] server started, listening on {}", Self::addr());
-        log::warn!("[socks5] server started, listening on {}", server.addr);
 
         loop {
-            match server.inner.accept().await {
+            match SERVER.get().unwrap().inner.accept().await {
                 Ok((conn, addr)) => {
                     log::debug!("[socks5] [{addr}] connection established");
                     tokio::spawn(async move {
@@ -118,33 +131,55 @@ impl Server {
         assoc: Associate<associate::NeedReply>,
         _addr: Address,
     ) -> Result<(), Error> {
-        async fn get_assoc_socket() -> Result<Arc<AssociatedUdpSocket>, IoError> {
+        async fn get_assoc_socket() -> Result<Arc<AssociatedUdpSocket>, Error> {
-            let socket = Socket::from(
+            let domain = match Server::addr() {
-                UdpSocket::bind(SERVER.get().unwrap().addr)
+                SocketAddr::V4(_) => Domain::IPV4,
-                    .await?
+                SocketAddr::V6(_) => Domain::IPV6,
-                    .into_std()?,
+            };
-            );
 
-            if let Some(dual_stack) = SERVER.get().unwrap().dual_stack {
+            let socket = Socket::new(domain, Type::DGRAM, Some(Protocol::UDP)).map_err(|err| {
-                // We already checked that the server address is IPv6
+                Error::Socket("failed to create socks5 server UDP associate socket", err)
-                socket.set_only_v6(!dual_stack)?;
+            })?;
+
+            if let Some(dual_stack) = Server::dual_stack() {
+                socket.set_only_v6(!dual_stack).map_err(|err| {
+                    Error::Socket(
+                        "socks5 server UDP associate dual-stack socket setting error",
+                        err,
+                    )
+                })?;
             }
 
-            let socket = AssociatedUdpSocket::from((
+            socket.set_nonblocking(true).map_err(|err| {
-                UdpSocket::from_std(StdUdpSocket::from(socket))?,
+                Error::Socket(
-                SERVER.get().unwrap().max_pkt_size,
+                    "failed setting socks5 server UDP associate socket as non-blocking",
-            ));
+                    err,
+                )
+            })?;
 
-            Ok(Arc::new(socket))
+            socket
+                .bind(&SockAddr::from(Server::addr()))
+                .map_err(|err| {
+                    Error::Socket("failed to bind socks5 server UDP associate socket", err)
+                })?;
+
+            let socket = UdpSocket::from_std(StdUdpSocket::from(socket)).map_err(|err| {
+                Error::Socket("failed to create socks5 server UDP associate socket", err)
+            })?;
+
+            Ok(Arc::new(AssociatedUdpSocket::from((
+                socket,
+                Server::max_pkt_size(),
+            ))))
         }
 
-        match get_assoc_socket()
+        match get_assoc_socket().await {
-            .await
+            Ok(assoc_socket) => {
-            .and_then(|socket| socket.local_addr().map(|addr| (socket, addr)))
-        {
-            Ok((assoc_socket, assoc_addr)) => {
                 let assoc = assoc
-                    .reply(Reply::Succeeded, Address::SocketAddress(assoc_addr))
+                    .reply(
+                        Reply::Succeeded,
+                        Address::SocketAddress(assoc_socket.local_addr().unwrap()),
+                    )
                     .await?;
                 Self::send_pkt(assoc, assoc_socket).await
             }
@@ -308,4 +343,16 @@ impl Server {
             Err(err) => log::error!("[socks5] [send] {err}"),
         }
     }
+
+    fn addr() -> SocketAddr {
+        SERVER.get().unwrap().inner.local_addr().unwrap()
+    }
+
+    fn dual_stack() -> Option<bool> {
+        SERVER.get().unwrap().dual_stack
+    }
+
+    fn max_pkt_size() -> usize {
+        SERVER.get().unwrap().max_pkt_size
+    }
 }

tuic-server/src/main.rs

@@ -64,8 +64,8 @@ pub enum Error {
     AuthFailed(Uuid),
     #[error("received packet from unexpected source")]
     UnexpectedPacketSource,
-    #[error("create UDP session socket failed: {0}")]
+    #[error("{0}: {1}")]
-    CreateUdpSessionSocket(IoError),
+    Socket(&'static str, IoError),
-    #[error("{0} resolved to {1} but IPv6 UDP relay disabled")]
+    #[error("{0} resolved to {1} but IPv6 UDP relaying is disabled")]
     UdpRelayIpv6Disabled(Address, SocketAddr),
 }

tuic-server/src/server.rs

@@ -13,7 +13,7 @@ use quinn::{
 };
 use register_count::{Counter, Register};
 use rustls::{version, ServerConfig as RustlsServerConfig};
-use socket2::Socket;
+use socket2::{Domain, Protocol, SockAddr, Socket, Type};
 use std::{
     collections::{hash_map::Entry, HashMap},
     future::Future,
@@ -95,23 +95,32 @@ impl Server {
 
         config.transport_config(Arc::new(tp_cfg));
 
-        let socket = Socket::from(StdUdpSocket::bind(cfg.server)?);
+        let socket = {
+            let domain = match cfg.server {
+                SocketAddr::V4(_) => Domain::IPV4,
+                SocketAddr::V6(_) => Domain::IPV6,
+            };
 
-        if let Some(dual_stack) = cfg.dual_stack {
+            let socket = Socket::new(domain, Type::DGRAM, Some(Protocol::UDP))
-            if cfg.server.is_ipv4() && dual_stack {
+                .map_err(|err| Error::Socket("failed to create endpoint UDP socket", err))?;
-                return Err(Error::from(IoError::new(
+
-                    ErrorKind::Unsupported,
+            if let Some(dual_stack) = cfg.dual_stack {
-                    "IPv4 socket cannot be dual stack",
+                socket.set_only_v6(!dual_stack).map_err(|err| {
-                )));
+                    Error::Socket("endpoint dual-stack socket setting error", err)
+                })?;
             }
 
-            socket.set_only_v6(!dual_stack)?;
+            socket
-        }
+                .bind(&SockAddr::from(cfg.server))
+                .map_err(|err| Error::Socket("failed to bind endpoint UDP socket", err))?;
+
+            StdUdpSocket::from(socket)
+        };
 
         let ep = Endpoint::new(
             EndpointConfig::default(),
             Some(config),
-            StdUdpSocket::from(socket),
+            socket,
             Arc::new(TokioRuntime),
         )?;
 
@@ -492,11 +501,8 @@ impl Connection {
                 (session.socket_v4.clone(), session.socket_v6.clone())
             }
             Entry::Vacant(entry) => {
-                let session = entry.insert(
+                let session = entry
-                    UdpSession::new(assoc_id, self.clone(), self.udp_relay_ipv6)
+                    .insert(UdpSession::new(assoc_id, self.clone(), self.udp_relay_ipv6).await?);
-                        .await
-                        .map_err(Error::CreateUdpSessionSocket)?,
-                );
 
                 (session.socket_v4.clone(), session.socket_v6.clone())
             }
@@ -592,17 +598,33 @@ struct UdpSession {
 }
 
 impl UdpSession {
-    async fn new(assoc_id: u16, conn: Connection, udp_relay_ipv6: bool) -> Result<Self, IoError> {
+    async fn new(assoc_id: u16, conn: Connection, udp_relay_ipv6: bool) -> Result<Self, Error> {
-        let socket_v4 =
+        let socket_v4 = Arc::new(
-            Arc::new(UdpSocket::bind(SocketAddr::from((Ipv4Addr::UNSPECIFIED, 0))).await?);
+            UdpSocket::bind(SocketAddr::from((Ipv4Addr::UNSPECIFIED, 0)))
+                .await
+                .map_err(|err| Error::Socket("failed to create UDP associate IPv4 socket", err))?,
+        );
         let socket_v6 = if udp_relay_ipv6 {
-            let socket = Socket::from(
+            let socket = Socket::new(Domain::IPV6, Type::DGRAM, Some(Protocol::UDP))
-                UdpSocket::bind(SocketAddr::from((Ipv6Addr::UNSPECIFIED, 0)))
+                .map_err(|err| Error::Socket("failed to create UDP associate IPv6 socket", err))?;
-                    .await?
-                    .into_std()?,
-            );
 
-            socket.set_only_v6(true)?;
+            socket.set_nonblocking(true).map_err(|err| {
+                Error::Socket(
+                    "failed setting UDP associate IPv6 socket as non-blocking",
+                    err,
+                )
+            })?;
+
+            socket.set_only_v6(true).map_err(|err| {
+                Error::Socket("failed setting UDP associate IPv6 socket as IPv6-only", err)
+            })?;
+
+            socket
+                .bind(&SockAddr::from(SocketAddr::from((
+                    Ipv6Addr::UNSPECIFIED,
+                    0,
+                ))))
+                .map_err(|err| Error::Socket("failed to bind UDP associate IPv6 socket", err))?;
 
             Some(Arc::new(UdpSocket::from_std(StdUdpSocket::from(socket))?))
         } else {