From 626ee8cfbb6dd48d1dc6ee35f87fbe5417d08c8f Mon Sep 17 00:00:00 2001
From: WGH <wgh@torlan.ru>
Date: Sun, 5 Apr 2026 00:16:33 +0300
Subject: [PATCH] Implement IntoRawFd for Socket

This is useful for cases when you initialize a socket outside async
runtime (e.g. to create netlink socket in the parent namespace before
doing unshare syscall), and wrap it into async socket later on.

    let mut sock = Socket::new(NETLINK_ROUTE).unwrap();

    let addr = SocketAddr::new(0, 0);
    sock.bind(&addr).unwrap();

    for group in GROUPS {
        sock.add_membership(*group as u32).unwrap();
    }

    // do some unsafe single-threaded things like switch namespaces here,
    // and then initialize async runtime

    let sock = unsafe { TokioSocket::from_raw_fd(sock.into_raw_fd()) };

    let (conn, _handle, mut messages) = rtnetlink::from_socket(sock);

    tokio::spawn(conn);

    while let Some((message, _)) = messages.next().await {
        dbg!(message);
    }
---
 src/socket.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/socket.rs b/src/socket.rs
index f9bcb32..ecf0838 100644
--- a/src/socket.rs
+++ b/src/socket.rs
@@ -4,7 +4,7 @@ use std::{
     io::{Error, Result},
     mem,
     os::{
-        fd::{AsFd, BorrowedFd, FromRawFd},
+        fd::{AsFd, BorrowedFd, FromRawFd, IntoRawFd},
         unix::io::{AsRawFd, RawFd},
     },
 };
@@ -69,6 +69,14 @@ impl AsFd for Socket {
     }
 }
 
+impl IntoRawFd for Socket {
+    fn into_raw_fd(self) -> RawFd {
+        let fd = self.0;
+        std::mem::forget(self);
+        fd
+    }
+}
+
 impl FromRawFd for Socket {
     unsafe fn from_raw_fd(fd: RawFd) -> Self {
         Socket(fd)