feat(tun): auto route on macos (#592)

clash/tests/data/config/rules.yaml

@@ -4,13 +4,13 @@ socks-port: 8889
 mixed-port: 8899
 
 tun:
-  enable: false
+  enable: true
   device-id: "dev://utun1989"
-  route-all: false
+  route-all: true
   gateway: "198.19.0.1/32"
-  routes:
-    - 0.0.0.0/1
-    - 128.0.0.0/1
+  # routes:
+  #   - 0.0.0.0/1
+  #   - 128.0.0.0/1
 
 ipv6: true
 

clash_lib/src/proxy/tun/inbound.rs

@@ -19,6 +19,11 @@ use crate::{
     Error, Runner,
 };
 
+#[cfg(target_os = "macos")]
+use crate::defer;
+#[cfg(target_os = "macos")]
+use crate::proxy::tun::routes;
+
 async fn handle_inbound_stream(
     stream: netstack::TcpStream,
     local_addr: SocketAddr,
@@ -200,6 +205,13 @@ pub fn get_runner(
         netstack::NetStack::with_buffer_size(512, 256).map_err(map_io_error)?;
 
     Ok(Some(Box::pin(async move {
+        #[cfg(target_os = "macos")]
+        defer! {
+            warn!("cleaning up routes");
+
+            let _ = routes::maybe_routes_clean_up();
+        }
+
         let framed = tun.into_framed();
 
         let (mut tun_sink, mut tun_stream) = framed.split();

clash_lib/src/proxy/tun/routes/macos.rs

@@ -1,9 +1,117 @@
+use std::net::Ipv4Addr;
+
 use ipnet::IpNet;
 use tracing::warn;
 
-use crate::proxy::utils::OutboundInterface;
+use crate::{
+    common::errors::new_io_error,
+    proxy::utils::{get_outbound_interface, OutboundInterface},
+};
+
+/// let's assume that the `route` command is available on macOS
+pub fn add_route(via: &OutboundInterface, dest: &IpNet) -> std::io::Result<()> {
+    let cmd = std::process::Command::new("route")
+        .arg("add")
+        .arg("-net")
+        .arg(dest.to_string())
+        .arg("-interface")
+        .arg(&via.name)
+        .output()?;
+
+    warn!("executing: route add -net {} -interface {}", dest, via.name);
+    if !cmd.status.success() {
+        Err(new_io_error("add route failed"))
+    } else {
+        Ok(())
+    }
+}
+
+fn get_default_gateway() -> std::io::Result<Option<Ipv4Addr>> {
+    let cmd = std::process::Command::new("route")
+        .arg("-n")
+        .arg("get")
+        .arg("default")
+        .output()?;
+
+    if !cmd.status.success() {
+        return Ok(None);
+    }
+
+    let output = String::from_utf8_lossy(&cmd.stdout);
+
+    let mut gateway = None;
+    for line in output.lines() {
+        if line.trim().contains("gateway:") {
+            gateway = line
+                .split_whitespace()
+                .last()
+                .and_then(|x| x.parse::<Ipv4Addr>().ok());
+            break;
+        }
+    }
+
+    Ok(gateway)
+}
+
+/// it seems to be fine to add the default route multiple times
+pub fn maybe_add_default_route() -> std::io::Result<()> {
+    let gateway = get_default_gateway()?;
+    if let Some(gateway) = gateway {
+        let default_interface =
+            get_outbound_interface().ok_or(new_io_error("get default interface"))?;
+
+        let cmd = std::process::Command::new("route")
+            .arg("add")
+            .arg("-ifscope")
+            .arg(&default_interface.name)
+            .arg("0/0")
+            .arg(gateway.to_string())
+            .output()?;
+
+        warn!(
+            "executing: route add -ifscope {} 0/0 {}",
+            default_interface.name, gateway
+        );
+
+        if !cmd.status.success() {
+            Err(new_io_error("add default route failed"))
+        } else {
+            Ok(())
+        }
+    } else {
+        Err(new_io_error(
+            "cant set default route, default gateway not found",
+        ))
+    }
+}
+
+/// failing to delete the default route won't cause route failure
+pub fn maybe_routes_clean_up() -> std::io::Result<()> {
+    let gateway = get_default_gateway()?;
+    if let Some(gateway) = gateway {
+        let default_interface =
+            get_outbound_interface().ok_or(new_io_error("get default interface"))?;
+        let cmd = std::process::Command::new("route")
+            .arg("delete")
+            .arg("-ifscope")
+            .arg(&default_interface.name)
+            .arg("0/0")
+            .arg(gateway.to_string())
+            .output()?;
+
+        warn!(
+            "executing: route delete -ifscope {} 0/0 {}",
+            default_interface.name, gateway
+        );
 
-pub fn add_route(_: &OutboundInterface, _: &IpNet) -> std::io::Result<()> {
-    warn!("add_route is not implemented on macOS");
-    Ok(())
+        if !cmd.status.success() {
+            Err(new_io_error("delete default route failed"))
+        } else {
+            Ok(())
+        }
+    } else {
+        Err(new_io_error(
+            "cant delete default route, default gateway not found",
+        ))
+    }
 }

clash_lib/src/proxy/tun/routes/mod.rs

@@ -7,6 +7,8 @@ use windows::add_route;
 mod macos;
 #[cfg(target_os = "macos")]
 use macos::add_route;
+#[cfg(target_os = "macos")]
+pub use macos::maybe_routes_clean_up;
 
 #[cfg(target_os = "linux")]
 mod linux;
@@ -64,6 +66,11 @@ pub fn maybe_add_routes(cfg: &TunConfig, tun_name: &str) -> std::io::Result<()>
             for r in default_routes {
                 add_route(&tun_iface, &r).map_err(map_io_error)?;
             }
+
+            #[cfg(target_os = "macos")]
+            {
+                macos::maybe_add_default_route()?;
+            }
         } else {
             for r in &cfg.routes {
                 add_route(&tun_iface, r).map_err(map_io_error)?;