Add v4 and v6 versions of bind_device_by_index.

src/sys/unix.rs

@@ -1833,6 +1833,33 @@ impl crate::Socket {
         .map(|_| ())
     }
 
+    /// This method is deprecated, use [`crate::Socket::bind_device_by_index_v4`].
+    #[cfg(all(
+        feature = "all",
+        any(
+            target_os = "ios",
+            target_os = "macos",
+            target_os = "tvos",
+            target_os = "watchos",
+        )
+    ))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(all(
+            feature = "all",
+            any(
+                target_os = "ios",
+                target_os = "macos",
+                target_os = "tvos",
+                target_os = "watchos",
+            )
+        )))
+    )]
+    #[deprecated = "Use `Socket::device_index_v4` instead"]
+    pub fn bind_device_by_index(&self, interface: Option<NonZeroU32>) -> io::Result<()> {
+        self.bind_device_by_index_v4(interface)
+    }
+
     /// Sets the value for `IP_BOUND_IF` option on this socket.
     ///
     /// If a socket is bound to an interface, only packets received from that
@@ -1864,11 +1891,47 @@ impl crate::Socket {
             )
         )))
     )]
-    pub fn bind_device_by_index(&self, interface: Option<NonZeroU32>) -> io::Result<()> {
+    pub fn bind_device_by_index_v4(&self, interface: Option<NonZeroU32>) -> io::Result<()> {
         let index = interface.map_or(0, NonZeroU32::get);
         unsafe { setsockopt(self.as_raw(), IPPROTO_IP, libc::IP_BOUND_IF, index) }
     }
 
+    /// Sets the value for `IPV6_BOUND_IF` option on this socket.
+    ///
+    /// If a socket is bound to an interface, only packets received from that
+    /// particular interface are processed by the socket.
+    ///
+    /// If `interface` is `None`, the binding is removed. If the `interface`
+    /// index is not valid, an error is returned.
+    ///
+    /// One can use [`libc::if_nametoindex`] to convert an interface alias to an
+    /// index.
+    #[cfg(all(
+        feature = "all",
+        any(
+            target_os = "ios",
+            target_os = "macos",
+            target_os = "tvos",
+            target_os = "watchos",
+        )
+    ))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(all(
+            feature = "all",
+            any(
+                target_os = "ios",
+                target_os = "macos",
+                target_os = "tvos",
+                target_os = "watchos",
+            )
+        )))
+    )]
+    pub fn bind_device_by_index_v6(&self, interface: Option<NonZeroU32>) -> io::Result<()> {
+        let index = interface.map_or(0, NonZeroU32::get);
+        unsafe { setsockopt(self.as_raw(), IPPROTO_IPV6, libc::IPV6_BOUND_IF, index) }
+    }
+
     /// Gets the value for `IP_BOUND_IF` option on this socket, i.e. the index
     /// for the interface to which the socket is bound.
     ///
@@ -1895,12 +1958,72 @@ impl crate::Socket {
             )
         )))
     )]
-    pub fn device_index(&self) -> io::Result<Option<NonZeroU32>> {
+    pub fn device_index_v4(&self) -> io::Result<Option<NonZeroU32>> {
         let index =
             unsafe { getsockopt::<libc::c_uint>(self.as_raw(), IPPROTO_IP, libc::IP_BOUND_IF)? };
         Ok(NonZeroU32::new(index))
     }
 
+    /// This method is deprecated, use [`crate::Socket::device_index_v4`].
+    #[cfg(all(
+        feature = "all",
+        any(
+            target_os = "ios",
+            target_os = "macos",
+            target_os = "tvos",
+            target_os = "watchos",
+        )
+    ))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(all(
+            feature = "all",
+            any(
+                target_os = "ios",
+                target_os = "macos",
+                target_os = "tvos",
+                target_os = "watchos",
+            )
+        )))
+    )]
+    #[deprecated = "Use `Socket::device_index_v4` instead"]
+    pub fn device_index(&self) -> io::Result<Option<NonZeroU32>> {
+        self.device_index_v4()
+    }
+
+    /// Gets the value for `IPV6_BOUND_IF` option on this socket, i.e. the index
+    /// for the interface to which the socket is bound.
+    ///
+    /// Returns `None` if the socket is not bound to any interface, otherwise
+    /// returns an interface index.
+    #[cfg(all(
+        feature = "all",
+        any(
+            target_os = "ios",
+            target_os = "macos",
+            target_os = "tvos",
+            target_os = "watchos",
+        )
+    ))]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(all(
+            feature = "all",
+            any(
+                target_os = "ios",
+                target_os = "macos",
+                target_os = "tvos",
+                target_os = "watchos",
+            )
+        )))
+    )]
+    pub fn device_index_v6(&self) -> io::Result<Option<NonZeroU32>> {
+        let index = unsafe {
+            getsockopt::<libc::c_uint>(self.as_raw(), IPPROTO_IPV6, libc::IPV6_BOUND_IF)?
+        };
+        Ok(NonZeroU32::new(index))
+    }
+
     /// Get the value of the `SO_INCOMING_CPU` option on this socket.
     ///
     /// For more information about this option, see [`set_cpu_affinity`].

tests/socket.rs

@@ -926,7 +926,7 @@ fn device() {
     const INTERFACES: &[&str] = &["lo\0", "lo0\0", "en0\0"];
 
     let socket = Socket::new(Domain::IPV4, Type::STREAM, None).unwrap();
-    assert_eq!(socket.device_index().unwrap(), None);
+    assert_eq!(socket.device_index_v4().unwrap(), None);
 
     for interface in INTERFACES.iter() {
         let iface_index = std::num::NonZeroU32::new(unsafe {
@@ -936,7 +936,7 @@ fn device() {
         if iface_index.is_none() {
             continue;
         }
-        if let Err(err) = socket.bind_device_by_index(iface_index) {
+        if let Err(err) = socket.bind_device_by_index_v4(iface_index) {
             // Network interface is not available try another.
             if matches!(err.raw_os_error(), Some(libc::ENODEV)) {
                 eprintln!("error binding to device (`{interface}`): {err}");
@@ -945,10 +945,55 @@ fn device() {
                 panic!("unexpected error binding device: {}", err);
             }
         }
-        assert_eq!(socket.device_index().unwrap(), iface_index);
+        assert_eq!(socket.device_index_v4().unwrap(), iface_index);
 
-        socket.bind_device_by_index(None).unwrap();
-        assert_eq!(socket.device_index().unwrap(), None);
+        socket.bind_device_by_index_v4(None).unwrap();
+        assert_eq!(socket.device_index_v4().unwrap(), None);
+        // Just need to do it with one interface.
+        return;
+    }
+
+    panic!("failed to bind to any device.");
+}
+
+#[cfg(all(
+    feature = "all",
+    any(
+        target_os = "ios",
+        target_os = "macos",
+        target_os = "tvos",
+        target_os = "watchos",
+    )
+))]
+#[test]
+fn device_v6() {
+    // Some common network interface on macOS.
+    const INTERFACES: &[&str] = &["lo\0", "lo0\0", "en0\0"];
+
+    let socket = Socket::new(Domain::IPV6, Type::STREAM, None).unwrap();
+    assert_eq!(socket.device_index_v6().unwrap(), None);
+
+    for interface in INTERFACES.iter() {
+        let iface_index = std::num::NonZeroU32::new(unsafe {
+            libc::if_nametoindex(interface.as_ptr() as *const _)
+        });
+        // If no index is returned, try another interface alias
+        if iface_index.is_none() {
+            continue;
+        }
+        if let Err(err) = socket.bind_device_by_index_v6(iface_index) {
+            // Network interface is not available try another.
+            if matches!(err.raw_os_error(), Some(libc::ENODEV)) {
+                eprintln!("error binding to device (`{interface}`): {err}");
+                continue;
+            } else {
+                panic!("unexpected error binding device: {}", err);
+            }
+        }
+        assert_eq!(socket.device_index_v6().unwrap(), iface_index);
+
+        socket.bind_device_by_index_v6(None).unwrap();
+        assert_eq!(socket.device_index_v6().unwrap(), None);
         // Just need to do it with one interface.
         return;
     }