1 files changed, 53 insertions, 0 deletions
diff --git a/third_party/rust/mio/src/sys/windows/udp.rs b/third_party/rust/mio/src/sys/windows/udp.rs
new file mode 100644
index 0000000000..825ecccff4
--- /dev/null
+++ b/third_party/rust/mio/src/sys/windows/udp.rs
@@ -0,0 +1,53 @@
+use std::io;
+use std::mem::{self, MaybeUninit};
+use std::net::{self, SocketAddr};
+use std::os::windows::io::{AsRawSocket, FromRawSocket};
+use std::os::windows::raw::SOCKET as StdSocket; // winapi uses usize, stdlib uses u32/u64.
+
+use winapi::ctypes::c_int;
+use winapi::shared::ws2def::IPPROTO_IPV6;
+use winapi::shared::ws2ipdef::IPV6_V6ONLY;
+use winapi::um::winsock2::{bind as win_bind, closesocket, getsockopt, SOCKET_ERROR, SOCK_DGRAM};
+
+use crate::sys::windows::net::{init, new_ip_socket, socket_addr};
+
+pub fn bind(addr: SocketAddr) -> io::Result<net::UdpSocket> {
+    init();
+    new_ip_socket(addr, SOCK_DGRAM).and_then(|socket| {
+        let (raw_addr, raw_addr_length) = socket_addr(&addr);
+        syscall!(
+            win_bind(socket, raw_addr.as_ptr(), raw_addr_length,),
+            PartialEq::eq,
+            SOCKET_ERROR
+        )
+        .map_err(|err| {
+            // Close the socket if we hit an error, ignoring the error
+            // from closing since we can't pass back two errors.
+            let _ = unsafe { closesocket(socket) };
+            err
+        })
+        .map(|_| unsafe { net::UdpSocket::from_raw_socket(socket as StdSocket) })
+    })
+}
+
+pub(crate) fn only_v6(socket: &net::UdpSocket) -> io::Result<bool> {
+    let mut optval: MaybeUninit<c_int> = MaybeUninit::uninit();
+    let mut optlen = mem::size_of::<c_int>() as c_int;
+
+    syscall!(
+        getsockopt(
+            socket.as_raw_socket() as usize,
+            IPPROTO_IPV6 as c_int,
+            IPV6_V6ONLY as c_int,
+            optval.as_mut_ptr().cast(),
+            &mut optlen,
+        ),
+        PartialEq::eq,
+        SOCKET_ERROR
+    )?;
+
+    debug_assert_eq!(optlen as usize, mem::size_of::<c_int>());
+    // Safety: `getsockopt` initialised `optval` for us.
+    let optval = unsafe { optval.assume_init() };
+    Ok(optval != 0)
+}