feat(local): Allow configuring udp associate addr

User might want to bind the socket to a different address than what is advertised in the Socks 5 UDP Associate responses. This adds a new command line option to control only that but to still default to udp bind addr and local address. Example: sslocal --local-addr 0.0.0.0:1080 --udp-associate-addr 10.51.1.1:1080 -U Here the server would without this change respond to UDP Associate request with address 0.0.0.0:1080. With the new switch, it responds 10.51.1.1:1080.
shadowsocks · Aug 13, 2024 · 0041f62 · 0041f62
1 parent 4c2bdae
commit 0041f62
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Showing 6 changed files with 48 additions and 17 deletions.
diff --git a/crates/shadowsocks-service/src/config.rs b/crates/shadowsocks-service/src/config.rs
@@ -905,6 +905,9 @@ pub struct LocalConfig {
     /// Resolving Android's issue: [shadowsocks/shadowsocks-android#2571](https://github.com/shadowsocks/shadowsocks-android/issues/2571)
     pub udp_addr: Option<ServerAddr>,
 
+    /// UDP Associate address. Uses `udp_addr` if not specified
+    pub udp_associate_addr: Option<ServerAddr>,
+
     /// Destination address for tunnel
     #[cfg(feature = "local-tunnel")]
     pub forward_addr: Option<Address>,
@@ -1027,6 +1030,7 @@ impl LocalConfig {
 
             mode,
             udp_addr: None,
+            udp_associate_addr: None,
 
             #[cfg(feature = "local-tunnel")]
             forward_addr: None,

diff --git a/crates/shadowsocks-service/src/local/mod.rs b/crates/shadowsocks-service/src/local/mod.rs
@@ -310,6 +310,9 @@ impl Server {
                     if let Some(b) = local_config.udp_addr {
                         server_builder.set_udp_bind_addr(b.clone());
                     }
+                    if let Some(b) = local_config.udp_associate_addr {
+                        server_builder.set_udp_associate_addr(b.clone());
+                    }
 
                     #[cfg(target_os = "macos")]
                     if let Some(n) = local_config.launchd_tcp_socket_name {

diff --git a/crates/shadowsocks-service/src/local/socks/server/mod.rs b/crates/shadowsocks-service/src/local/socks/server/mod.rs
@@ -25,6 +25,7 @@ pub struct SocksBuilder {
     udp_expiry_duration: Option<Duration>,
     udp_capacity: Option<usize>,
     udp_bind_addr: Option<ServerAddr>,
+    udp_associate_addr: Option<ServerAddr>,
     socks5_auth: Socks5AuthConfig,
     client_config: ServerAddr,
     balancer: PingBalancer,
@@ -53,6 +54,7 @@ impl SocksBuilder {
             udp_expiry_duration: None,
             udp_capacity: None,
             udp_bind_addr: None,
+            udp_associate_addr: None,
             socks5_auth: Socks5AuthConfig::default(),
             client_config,
             balancer,
@@ -86,6 +88,10 @@ impl SocksBuilder {
         self.udp_bind_addr = Some(a);
     }
 
+    pub fn set_udp_associate_addr(&mut self, a: ServerAddr) {
+        self.udp_associate_addr = Some(a);
+    }
+
     /// Set SOCKS5 Username/Password Authentication configuration
     pub fn set_socks5_auth(&mut self, p: Socks5AuthConfig) {
         self.socks5_auth = p;
@@ -104,14 +110,20 @@ impl SocksBuilder {
     }
 
     pub async fn build(self) -> io::Result<Socks> {
-        let udp_bind_addr = self.udp_bind_addr.unwrap_or_else(|| self.client_config.clone());
+        let udp_bind_addr = self.udp_bind_addr.clone().unwrap_or_else(|| self.client_config.clone());
+        let udp_associate_addr: ServerAddr = self
+            .udp_associate_addr
+            .as_ref()
+            .or_else(|| self.udp_bind_addr.as_ref())
+            .unwrap_or_else(|| &self.client_config)
+            .clone();
 
         let mut udp_server = None;
         if self.mode.enable_udp() {
             #[allow(unused_mut)]
             let mut builder = Socks5UdpServerBuilder::new(
                 self.context.clone(),
-                udp_bind_addr.clone(),
+                udp_bind_addr,
                 self.udp_expiry_duration,
                 self.udp_capacity,
                 self.balancer.clone(),
@@ -132,7 +144,7 @@ impl SocksBuilder {
             let mut builder = SocksTcpServerBuilder::new(
                 self.context.clone(),
                 self.client_config,
-                udp_bind_addr,
+                udp_associate_addr,
                 self.balancer.clone(),
                 self.mode,
                 self.socks5_auth,

diff --git a/crates/shadowsocks-service/src/local/socks/server/server.rs b/crates/shadowsocks-service/src/local/socks/server/server.rs
@@ -18,7 +18,7 @@ use super::socks5::{Socks5TcpHandler, Socks5UdpServer};
 pub struct SocksTcpServerBuilder {
     context: Arc<ServiceContext>,
     client_config: ServerAddr,
-    udp_bind_addr: ServerAddr,
+    udp_associate_addr: ServerAddr,
     balancer: PingBalancer,
     mode: Mode,
     socks5_auth: Arc<Socks5AuthConfig>,
@@ -30,15 +30,15 @@ impl SocksTcpServerBuilder {
     pub(crate) fn new(
         context: Arc<ServiceContext>,
         client_config: ServerAddr,
-        udp_bind_addr: ServerAddr,
+        udp_associate_addr: ServerAddr,
         balancer: PingBalancer,
         mode: Mode,
         socks5_auth: Socks5AuthConfig,
     ) -> SocksTcpServerBuilder {
         SocksTcpServerBuilder {
             context,
             client_config,
-            udp_bind_addr,
+            udp_associate_addr,
             balancer,
             mode,
             socks5_auth: Arc::new(socks5_auth),
@@ -74,7 +74,7 @@ impl SocksTcpServerBuilder {
         Ok(SocksTcpServer {
             context: self.context,
             listener,
-            udp_bind_addr: self.udp_bind_addr,
+            udp_associate_addr: self.udp_associate_addr,
             balancer: self.balancer,
             mode: self.mode,
             socks5_auth: self.socks5_auth,
@@ -86,7 +86,7 @@ impl SocksTcpServerBuilder {
 pub struct SocksTcpServer {
     context: Arc<ServiceContext>,
     listener: ShadowTcpListener,
-    udp_bind_addr: ServerAddr,
+    udp_associate_addr: ServerAddr,
     balancer: PingBalancer,
     mode: Mode,
     socks5_auth: Arc<Socks5AuthConfig>,
@@ -103,7 +103,7 @@ impl SocksTcpServer {
         info!("shadowsocks socks TCP listening on {}", self.listener.local_addr()?);
 
         // If UDP is enabled, SOCK5 UDP_ASSOCIATE command will let client to send requests to this address
-        let udp_bind_addr = Arc::new(self.udp_bind_addr);
+        let udp_associate_addr = Arc::new(self.udp_associate_addr);
         #[cfg(feature = "local-http")]
         let http_handler = HttpConnectionHandler::new(self.context.clone(), self.balancer.clone());
 
@@ -119,7 +119,7 @@ impl SocksTcpServer {
 
             let handler = SocksTcpHandler {
                 context: self.context.clone(),
-                udp_bind_addr: udp_bind_addr.clone(),
+                udp_associate_addr: udp_associate_addr.clone(),
                 stream,
                 balancer: self.balancer.clone(),
                 peer_addr,
@@ -140,7 +140,7 @@ impl SocksTcpServer {
 
 struct SocksTcpHandler {
     context: Arc<ServiceContext>,
-    udp_bind_addr: Arc<ServerAddr>,
+    udp_associate_addr: Arc<ServerAddr>,
     stream: TcpStream,
     balancer: PingBalancer,
     peer_addr: SocketAddr,
@@ -155,7 +155,7 @@ impl SocksTcpHandler {
     async fn handle_tcp_client(self) -> io::Result<()> {
         let handler = Socks5TcpHandler::new(
             self.context,
-            self.udp_bind_addr,
+            self.udp_associate_addr,
             self.balancer,
             self.mode,
             self.socks5_auth,
@@ -183,7 +183,7 @@ impl SocksTcpHandler {
             0x05 => {
                 let handler = Socks5TcpHandler::new(
                     self.context,
-                    self.udp_bind_addr,
+                    self.udp_associate_addr,
                     self.balancer,
                     self.mode,
                     self.socks5_auth,

diff --git a/crates/shadowsocks-service/src/local/socks/server/socks5/tcprelay.rs b/crates/shadowsocks-service/src/local/socks/server/socks5/tcprelay.rs
@@ -31,7 +31,7 @@ use crate::{
 
 pub struct Socks5TcpHandler {
     context: Arc<ServiceContext>,
-    udp_bind_addr: Arc<ServerAddr>,
+    udp_associate_addr: Arc<ServerAddr>,
     balancer: PingBalancer,
     mode: Mode,
     auth: Arc<Socks5AuthConfig>,
@@ -40,14 +40,14 @@ pub struct Socks5TcpHandler {
 impl Socks5TcpHandler {
     pub fn new(
         context: Arc<ServiceContext>,
-        udp_bind_addr: Arc<ServerAddr>,
+        udp_associate_addr: Arc<ServerAddr>,
         balancer: PingBalancer,
         mode: Mode,
         auth: Arc<Socks5AuthConfig>,
     ) -> Socks5TcpHandler {
         Socks5TcpHandler {
             context,
-            udp_bind_addr,
+            udp_associate_addr,
             balancer,
             mode,
             auth,
@@ -304,7 +304,7 @@ impl Socks5TcpHandler {
 
         // shadowsocks accepts both TCP and UDP from the same address
 
-        let rh = TcpResponseHeader::new(socks5::Reply::Succeeded, self.udp_bind_addr.as_ref().into());
+        let rh = TcpResponseHeader::new(socks5::Reply::Succeeded, self.udp_associate_addr.as_ref().into());
         rh.write_to(&mut stream).await?;
 
         // Hold connection until EOF.

diff --git a/src/service/local.rs b/src/service/local.rs
@@ -131,6 +131,14 @@ pub fn define_command_line_options(mut app: Command) -> Command {
             .value_parser(vparser::parse_server_addr)
             .help("UDP relay's bind address, default is the same as local-addr"),
     )
+    .arg(
+        Arg::new("UDP_ASSOCIATE_ADDR")
+        .long("udp-associate-addr")
+        .num_args(1)
+        .action(ArgAction::Set)
+        .value_parser(vparser::parse_server_addr)
+        .help("UDP relay's externally visible address return in UDP Associate responses"),
+    )
     .arg(
         Arg::new("SERVER_ADDR")
             .short('s')
@@ -731,6 +739,10 @@ pub fn create(matches: &ArgMatches) -> Result<(Runtime, impl Future<Output = Exi
                 local_config.udp_addr = Some(udp_bind_addr);
             }
 
+            if let Some(udp_associate_addr) = matches.get_one::<ServerAddr>("UDP_ASSOCIATE_ADDR").cloned() {
+                local_config.udp_associate_addr = Some(udp_associate_addr);
+            }
+
             #[cfg(feature = "local-tunnel")]
             if let Some(addr) = matches.get_one::<Address>("FORWARD_ADDR").cloned() {
                 local_config.forward_addr = Some(addr);