adapt L4Re network interface mock to #87329

Copy the relevant trait implementations from the Unix default.

library/std/src/sys/unix/l4re.rs

@@ -13,6 +13,7 @@ pub mod net {
     use crate::fmt;
     use crate::io::{self, IoSlice, IoSliceMut};
     use crate::net::{Ipv4Addr, Ipv6Addr, Shutdown, SocketAddr};
+    use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
     use crate::sys::fd::FileDesc;
     use crate::sys_common::{AsInner, FromInner, IntoInner};
     use crate::time::Duration;
@@ -123,21 +124,45 @@ pub mod net {
         }
     }
 
-    impl AsInner<libc::c_int> for Socket {
-        fn as_inner(&self) -> &libc::c_int {
-            self.0.as_inner()
+    impl AsInner<FileDesc> for Socket {
+        fn as_inner(&self) -> &FileDesc {
+            &self.0
         }
     }
 
-    impl FromInner<libc::c_int> for Socket {
-        fn from_inner(fd: libc::c_int) -> Socket {
-            Socket(FileDesc::new(fd))
+    impl FromInner<FileDesc> for Socket {
+        fn from_inner(file_desc: FileDesc) -> Socket {
+            Socket(file_desc)
         }
     }
 
-    impl IntoInner<libc::c_int> for Socket {
-        fn into_inner(self) -> libc::c_int {
-            self.0.into_raw()
+    impl IntoInner<FileDesc> for Socket {
+        fn into_inner(self) -> FileDesc {
+            self.0
+        }
+    }
+
+    impl AsFd for Socket {
+        fn as_fd(&self) -> BorrowedFd<'_> {
+            self.0.as_fd()
+        }
+    }
+
+    impl AsRawFd for Socket {
+        fn as_raw_fd(&self) -> RawFd {
+            self.0.as_raw_fd()
+        }
+    }
+
+    impl IntoRawFd for Socket {
+        fn into_raw_fd(self) -> RawFd {
+            self.0.into_raw_fd()
+        }
+    }
+
+    impl FromRawFd for Socket {
+        unsafe fn from_raw_fd(raw_fd: RawFd) -> Self {
+            Self(FromRawFd::from_raw_fd(raw_fd))
         }
     }