feat(client): enable HttpConnector::interface on macOS and Solarish systems (#176)

Author: hawkw

Cargo.toml

@@ -25,10 +25,11 @@ http-body = "1.0.0"
 bytes = "1.7.1"
 pin-project-lite = "0.2.4"
 futures-channel = { version = "0.3", optional = true }
-socket2 = { version = "0.5", optional = true, features = ["all"] }
+socket2 = { version = "0.5.9", optional = true, features = ["all"] }
 tracing = { version = "0.1", default-features = false, features = ["std"], optional = true }
 tokio = { version = "1", optional = true, default-features = false  }
 tower-service = { version = "0.3", optional = true }
+libc = { version = "0.2", optional = true }
 
 [dev-dependencies]
 hyper = { version = "1.4.0", features = ["full"] }
@@ -59,7 +60,7 @@ full = [
 ]
 
 client = ["hyper/client", "dep:tracing", "dep:futures-channel", "dep:tower-service"]
-client-legacy = ["client", "dep:socket2", "tokio/sync"]
+client-legacy = ["client", "dep:socket2", "tokio/sync", "dep:libc"]
 
 server = ["hyper/server"]
 server-auto = ["server", "http1", "http2"]

src/client/legacy/connect/http.rs

@@ -78,6 +78,16 @@ struct Config {
     recv_buffer_size: Option<usize>,
     #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
     interface: Option<String>,
+    #[cfg(any(
+        target_os = "illumos",
+        target_os = "ios",
+        target_os = "macos",
+        target_os = "solaris",
+        target_os = "tvos",
+        target_os = "visionos",
+        target_os = "watchos",
+    ))]
+    interface: Option<std::ffi::CString>,
     #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
     tcp_user_timeout: Option<Duration>,
 }
@@ -226,7 +236,18 @@ impl<R> HttpConnector<R> {
                 reuse_address: false,
                 send_buffer_size: None,
                 recv_buffer_size: None,
-                #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
+                #[cfg(any(
+                    target_os = "android",
+                    target_os = "fuchsia",
+                    target_os = "illumos",
+                    target_os = "ios",
+                    target_os = "linux",
+                    target_os = "macos",
+                    target_os = "solaris",
+                    target_os = "tvos",
+                    target_os = "visionos",
+                    target_os = "watchos",
+                ))]
                 interface: None,
                 #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
                 tcp_user_timeout: None,
@@ -353,22 +374,55 @@ impl<R> HttpConnector<R> {
         self
     }
 
-    /// Sets the value for the `SO_BINDTODEVICE` option on this socket.
+    /// Sets the name of the interface to bind sockets produced by this
+    /// connector.
+    ///
+    /// On Linux, this sets the `SO_BINDTODEVICE` option on this socket (see
+    /// [`man 7 socket`] for details). On macOS (and macOS-derived systems like
+    /// iOS), illumos, and Solaris, this will instead use the `IP_BOUND_IF`
+    /// socket option (see [`man 7p ip`]).
     ///
     /// If a socket is bound to an interface, only packets received from that particular
     /// interface are processed by the socket. Note that this only works for some socket
-    /// types, particularly AF_INET sockets.
+    /// types, particularly `AF_INET`` sockets.
     ///
     /// On Linux it can be used to specify a [VRF], but the binary needs
     /// to either have `CAP_NET_RAW` or to be run as root.
     ///
-    /// This function is only available on Android、Fuchsia and Linux.
+    /// This function is only available on the following operating systems:
+    /// - Linux, including Android
+    /// - Fuchsia
+    /// - illumos and Solaris
+    /// - macOS, iOS, visionOS, watchOS, and tvOS
     ///
     /// [VRF]: https://www.kernel.org/doc/Documentation/networking/vrf.txt
-    #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
+    /// [`man 7 socket`] https://man7.org/linux/man-pages/man7/socket.7.html
+    /// [`man 7p ip`]: https://docs.oracle.com/cd/E86824_01/html/E54777/ip-7p.html
+    #[cfg(any(
+        target_os = "android",
+        target_os = "fuchsia",
+        target_os = "illumos",
+        target_os = "ios",
+        target_os = "linux",
+        target_os = "macos",
+        target_os = "solaris",
+        target_os = "tvos",
+        target_os = "visionos",
+        target_os = "watchos",
+    ))]
     #[inline]
     pub fn set_interface<S: Into<String>>(&mut self, interface: S) -> &mut Self {
-        self.config_mut().interface = Some(interface.into());
+        let interface = interface.into();
+        #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
+        {
+            self.config_mut().interface = Some(interface);
+        }
+        #[cfg(not(any(target_os = "android", target_os = "fuchsia", target_os = "linux")))]
+        {
+            let interface = std::ffi::CString::new(interface)
+                .expect("interface name should not have nulls in it");
+            self.config_mut().interface = Some(interface);
+        }
         self
     }
 
@@ -789,12 +843,57 @@ fn connect(
         }
     }
 
-    #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
     // That this only works for some socket types, particularly AF_INET sockets.
+    #[cfg(any(
+        target_os = "android",
+        target_os = "fuchsia",
+        target_os = "illumos",
+        target_os = "ios",
+        target_os = "linux",
+        target_os = "macos",
+        target_os = "solaris",
+        target_os = "tvos",
+        target_os = "visionos",
+        target_os = "watchos",
+    ))]
     if let Some(interface) = &config.interface {
+        // On Linux-like systems, set the interface to bind using
+        // `SO_BINDTODEVICE`.
+        #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
         socket
             .bind_device(Some(interface.as_bytes()))
             .map_err(ConnectError::m("tcp bind interface error"))?;
+
+        // On macOS-like and Solaris-like systems, we instead use `IP_BOUND_IF`.
+        // This socket option desires an integer index for the interface, so we
+        // must first determine the index of the requested interface name using
+        // `if_nametoindex`.
+        #[cfg(any(
+            target_os = "illumos",
+            target_os = "ios",
+            target_os = "macos",
+            target_os = "solaris",
+            target_os = "tvos",
+            target_os = "visionos",
+            target_os = "watchos",
+        ))]
+        {
+            let idx = unsafe { libc::if_nametoindex(interface.as_ptr()) };
+            let idx = std::num::NonZeroU32::new(idx).ok_or_else(|| {
+                // If the index is 0, check errno and return an I/O error.
+                ConnectError::new(
+                    "error converting interface name to index",
+                    io::Error::last_os_error(),
+                )
+            })?;
+            // Different setsockopt calls are necessary depending on whether the
+            // address is IPv4 or IPv6.
+            match addr {
+                SocketAddr::V4(_) => socket.bind_device_by_index_v4(Some(idx)),
+                SocketAddr::V6(_) => socket.bind_device_by_index_v6(Some(idx)),
+            }
+            .map_err(ConnectError::m("tcp bind interface error"))?;
+        }
     }
 
     #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
@@ -1214,6 +1313,16 @@ mod tests {
                             target_os = "linux"
                         ))]
                         interface: None,
+                        #[cfg(any(
+                            target_os = "illumos",
+                            target_os = "ios",
+                            target_os = "macos",
+                            target_os = "solaris",
+                            target_os = "tvos",
+                            target_os = "visionos",
+                            target_os = "watchos",
+                        ))]
+                        interface: None,
                         #[cfg(any(
                             target_os = "android",
                             target_os = "fuchsia",