add LocalRedirector.unavailable_reason()

mitmproxy-rs/mitmproxy_rs/local.pyi

@@ -15,3 +15,5 @@ class LocalRedirector:
     def set_intercept(self, spec: str) -> None: ...
     def close(self) -> None: ...
     async def wait_closed(self) -> None: ...
+    @staticmethod
+    def unavailable_reason() -> str | None: ...

mitmproxy-rs/mitmproxy_rs/tun.pyi

@@ -4,7 +4,6 @@ from collections.abc import Awaitable, Callable
 from typing import final
 from . import Stream
 
-def unavailable_reason() -> str | None: ...
 async def create_tun_interface(
         handle_tcp_stream: Callable[[Stream], Awaitable[None]],
         handle_udp_stream: Callable[[Stream], Awaitable[None]],
@@ -16,3 +15,5 @@ class TunInterface:
     def close(self) -> None: ...
     async def wait_closed(self) -> None: ...
     def __repr__(self) -> str: ...
+    @staticmethod
+    def unavailable_reason() -> str | None: ...

mitmproxy-rs/src/lib.rs

@@ -62,7 +62,7 @@ mod mitmproxy_rs {
     #[pymodule]
     mod tun {
         #[pymodule_export]
-        use crate::server::{create_tun_interface, unavailable_reason, TunInterface};
+        use crate::server::{create_tun_interface, TunInterface};
     }
 
     #[pymodule]

mitmproxy-rs/src/server/local_redirector.rs

@@ -11,6 +11,9 @@ use std::path::Path;
 #[cfg(windows)]
 use std::path::PathBuf;
 
+#[cfg(target_os = "linux")]
+use nix::unistd;
+
 use crate::server::base::Server;
 use tokio::sync::mpsc;
 
@@ -62,6 +65,25 @@ impl LocalRedirector {
         self.server.wait_closed(py)
     }
 
+    /// Returns a `str` describing why local redirect mode is unavailable, or `None` if it is available.
+    ///
+    /// Reasons for unavailability may be an unsupported platform, or missing privileges.
+    #[staticmethod]
+    pub fn unavailable_reason() -> Option<String> {
+        #[cfg(any(windows, target_os = "macos"))]
+        return None;
+
+        #[cfg(target_os = "linux")]
+        if !unistd::geteuid().is_root() {
+            Some(String::from("mitmproxy is not running as root"))
+        } else {
+            None
+        }
+
+        #[cfg(not(any(windows, target_os = "macos", target_os = "linux")))]
+        Some(String::from("OS not supported for local redirect mode"))
+    }
+
     pub fn __repr__(&self) -> String {
         format!("Local Redirector({})", self.spec)
     }
@@ -135,6 +157,6 @@ pub fn start_local_redirector(
     }
     #[cfg(not(any(windows, target_os = "macos")))]
     Err(pyo3::exceptions::PyNotImplementedError::new_err(
-        "OS proxy mode is only available on Windows and macOS",
+        LocalRedirector::unavailable_reason(),
     ))
 }

mitmproxy-rs/src/server/mod.rs

@@ -5,6 +5,6 @@ mod udp;
 mod wireguard;
 
 pub use local_redirector::{start_local_redirector, LocalRedirector};
-pub use tun::{create_tun_interface, unavailable_reason, TunInterface};
+pub use tun::{create_tun_interface, TunInterface};
 pub use udp::{start_udp_server, UdpServer};
 pub use wireguard::{start_wireguard_server, WireGuardServer};

mitmproxy-rs/src/server/tun.rs

@@ -31,6 +31,22 @@ impl TunInterface {
         self.server.wait_closed(py)
     }
 
+    /// Returns a `str` describing why tun mode is unavailable, or `None` if TUN mode is available.
+    ///
+    /// Reasons for unavailability may be an unsupported platform, or missing privileges.
+    #[staticmethod]
+    pub fn unavailable_reason() -> Option<String> {
+        #[cfg(target_os = "linux")]
+        if !unistd::geteuid().is_root() {
+            Some(String::from("mitmproxy is not running as root"))
+        } else {
+            None
+        }
+
+        #[cfg(not(target_os = "linux"))]
+        Some(String::from("OS not supported for TUN proxy mode"))
+    }
+
     pub fn __repr__(&self) -> String {
         format!("TunInterface({})", self.tun_name)
     }
@@ -62,22 +78,6 @@ pub fn create_tun_interface(
     }
     #[cfg(not(target_os = "linux"))]
     Err(pyo3::exceptions::PyNotImplementedError::new_err(
-        unavailable_reason(),
+        TunInterface::unavailable_reason(),
     ))
 }
-
-/// Returns a `str` describing why tun mode is unavailable, or `None` if TUN mode is available.
-///
-/// Reasons for unavailability may be an unsupported platform, or missing privileges.
-#[pyfunction]
-pub fn unavailable_reason() -> Option<String> {
-    #[cfg(target_os = "linux")]
-    if !unistd::geteuid().is_root() {
-        Some(String::from("mitmproxy is not running as root"))
-    } else {
-        None
-    }
-
-    #[cfg(not(target_os = "linux"))]
-    Some(String::from("OS not supported for TUN proxy mode"))
-}