Don't assume representation of SocketAddr

Author: est31

quinn/src/platform/unix.rs

@@ -198,9 +198,12 @@ fn send(io: &mio::net::UdpSocket, transmits: &[Transmit]) -> io::Result<usize> {
     let mut msgs: [libc::mmsghdr; BATCH_SIZE] = unsafe { mem::zeroed() };
     let mut iovecs: [libc::iovec; BATCH_SIZE] = unsafe { mem::zeroed() };
     let mut cmsgs = [cmsg::Aligned([0u8; CMSG_LEN]); BATCH_SIZE];
+    let mut addrs: [CSocketAddr; BATCH_SIZE] = unsafe { mem::zeroed() };
     for (i, transmit) in transmits.iter().enumerate().take(BATCH_SIZE) {
+        addrs[i] = CSocketAddr::from_socket_addr(transmit.destination);
         prepare_msg(
             transmit,
+            &mut addrs[i],
             &mut msgs[i].msg_hdr,
             &mut iovecs[i],
             &mut cmsgs[i],
@@ -233,7 +236,8 @@ fn send(io: &mio::net::UdpSocket, transmits: &[Transmit]) -> io::Result<usize> {
     let mut ctrl = cmsg::Aligned([0u8; CMSG_LEN]);
     let mut sent = 0;
     while sent < transmits.len() {
-        prepare_msg(&transmits[sent], &mut hdr, &mut iov, &mut ctrl);
+        let mut addr = CSocketAddr::from_socket_addr(transmits[sent].destination);
+        prepare_msg(&transmits[sent], &mut addr, &mut hdr, &mut iov, &mut ctrl);
         let n = unsafe { libc::sendmsg(io.as_raw_fd(), &hdr, 0) };
         if n == -1 {
             let e = io::Error::last_os_error();
@@ -338,19 +342,58 @@ fn in_addr(addr: &Ipv4Addr) -> libc::in_addr {
     }
 }
 
+enum CSocketAddr {
+    V4(libc::sockaddr_in),
+    V6(libc::sockaddr_in6),
+}
+
+impl CSocketAddr {
+    fn from_socket_addr(addr: SocketAddr) -> Self {
+        match addr {
+            SocketAddr::V4(s) => CSocketAddr::V4(libc::sockaddr_in {
+                sin_family: libc::AF_INET as _,
+                sin_port: s.port().to_be(),
+                sin_addr: in_addr(s.ip()),
+                sin_zero: [0; 8],
+                #[cfg(any(target_os = "freebsd", target_os = "ios", target_os = "macos"))]
+                sin_len: 0,
+            }),
+            SocketAddr::V6(s) => CSocketAddr::V6(libc::sockaddr_in6 {
+                sin6_family: libc::AF_INET6 as _,
+                sin6_port: s.port().to_be(),
+                sin6_flowinfo: s.flowinfo(),
+                sin6_addr: libc::in6_addr {
+                    s6_addr: s.ip().octets(),
+                },
+                sin6_scope_id: s.scope_id(),
+            }),
+        }
+    }
+    fn ptr_and_len(&mut self) -> (*mut libc::c_void, usize) {
+        match self {
+            CSocketAddr::V4(ref mut addr) => (
+                addr as *mut _ as *mut _,
+                mem::size_of::<libc::sockaddr_in>(),
+            ),
+            CSocketAddr::V6(ref mut addr) => (
+                addr as *mut _ as *mut _,
+                mem::size_of::<libc::sockaddr_in6>(),
+            ),
+        }
+    }
+}
+
 fn prepare_msg(
     transmit: &Transmit,
+    dest_addr: &mut CSocketAddr,
     hdr: &mut libc::msghdr,
     iov: &mut libc::iovec,
     ctrl: &mut cmsg::Aligned<[u8; CMSG_LEN]>,
 ) {
     iov.iov_base = transmit.contents.as_ptr() as *const _ as *mut _;
     iov.iov_len = transmit.contents.len();
 
-    let (name, namelen) = match transmit.destination {
-        SocketAddr::V4(ref addr) => (addr as *const _ as _, mem::size_of::<libc::sockaddr_in>()),
-        SocketAddr::V6(ref addr) => (addr as *const _ as _, mem::size_of::<libc::sockaddr_in6>()),
-    };
+    let (name, namelen) = dest_addr.ptr_and_len();
     hdr.msg_name = name;
     hdr.msg_namelen = namelen as _;
     hdr.msg_iov = iov;