bind socket to device on macos (#9)

bind socket to device on macos

easytier-core/src/tunnels/common.rs

@@ -1,6 +1,6 @@
 use std::{
     collections::VecDeque,
-    net::IpAddr,
+    net::{IpAddr, SocketAddr},
     sync::Arc,
     task::{ready, Context, Poll},
 };
@@ -269,6 +269,39 @@ pub(crate) fn get_interface_name_by_ip(local_ip: &IpAddr) -> Option<String> {
     None
 }
 
+pub(crate) fn setup_sokcet2(
+    socket2_socket: &socket2::Socket,
+    bind_addr: &SocketAddr,
+) -> Result<(), TunnelError> {
+    socket2_socket.set_nonblocking(true)?;
+    socket2_socket.set_reuse_address(true)?;
+    socket2_socket.bind(&socket2::SockAddr::from(*bind_addr))?;
+
+    #[cfg(all(unix, not(target_os = "solaris"), not(target_os = "illumos")))]
+    socket2_socket.set_reuse_port(true)?;
+
+    // linux/mac does not use interface of bind_addr to send packet, so we need to bind device
+    // win can handle this with bind correctly
+    #[cfg(any(target_os = "ios", target_os = "macos"))]
+    if let Some(dev_name) = super::common::get_interface_name_by_ip(&bind_addr.ip()) {
+        // use IP_BOUND_IF to bind device
+        unsafe {
+            let dev_idx = nix::libc::if_nametoindex(dev_name.as_str().as_ptr() as *const i8);
+            tracing::warn!(?dev_idx, ?dev_name, "bind device");
+            socket2_socket.bind_device_by_index_v4(std::num::NonZeroU32::new(dev_idx))?;
+            tracing::warn!(?dev_idx, ?dev_name, "bind device doen");
+        }
+    }
+
+    #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
+    if let Some(dev_name) = super::common::get_interface_name_by_ip(&bind_addr.ip()) {
+        tracing::trace!(dev_name = ?dev_name, "bind device");
+        socket2_socket.bind_device(Some(dev_name.as_bytes()))?;
+    }
+
+    Ok(())
+}
+
 pub mod tests {
     use std::time::Instant;