Enum nix::sys::socket::ControlMessageOwned

#[non_exhaustive]
pub enum ControlMessageOwned {
    ScmRights(Vec<RawFd>),
    ScmTimestamp(TimeVal),
    Ipv4PacketInfo(in_pktinfo),
    Ipv6PacketInfo(in6_pktinfo),
    Ipv4RecvIf(sockaddr_dl),
    Ipv4RecvDstAddr(in_addr),
}

Available on crate features socket and uio only.

A type-safe wrapper around a single control message, as used with recvmsg.

Further reading

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

ScmRights(Vec<RawFd>)

Received version of ControlMessage::ScmRights

ScmTimestamp(TimeVal)

A message of type SCM_TIMESTAMP, containing the time the packet was received by the kernel.

See the kernel’s explanation in “SO_TIMESTAMP” of networking/timestamping.

Examples

// Set up
let message = "Ohayō!".as_bytes();
let in_socket = socket(
    AddressFamily::Inet,
    SockType::Datagram,
    SockFlag::empty(),
    None).unwrap();
setsockopt(&in_socket, sockopt::ReceiveTimestamp, &true).unwrap();
let localhost = SockaddrIn::from_str("127.0.0.1:0").unwrap();
bind(in_socket.as_raw_fd(), &localhost).unwrap();
let address: SockaddrIn = getsockname(in_socket.as_raw_fd()).unwrap();
// Get initial time
let time0 = SystemTime::now();
// Send the message
let iov = [IoSlice::new(message)];
let flags = MsgFlags::empty();
let l = sendmsg(in_socket.as_raw_fd(), &iov, &[], flags, Some(&address)).unwrap();
assert_eq!(message.len(), l);
// Receive the message
let mut buffer = vec![0u8; message.len()];
let mut cmsgspace = cmsg_space!(TimeVal);
let mut iov = [IoSliceMut::new(&mut buffer)];
let r = recvmsg::<SockaddrIn>(in_socket.as_raw_fd(), &mut iov, Some(&mut cmsgspace), flags)
    .unwrap();
let rtime = match r.cmsgs().next() {
    Some(ControlMessageOwned::ScmTimestamp(rtime)) => rtime,
    Some(_) => panic!("Unexpected control message"),
    None => panic!("No control message")
};
// Check the final time
let time1 = SystemTime::now();
// the packet's received timestamp should lie in-between the two system
// times, unless the system clock was adjusted in the meantime.
let rduration = Duration::new(rtime.tv_sec() as u64,
                              rtime.tv_usec() as u32 * 1000);
assert!(time0.duration_since(UNIX_EPOCH).unwrap() <= rduration);
assert!(rduration <= time1.duration_since(UNIX_EPOCH).unwrap());
// Close socket

Ipv4PacketInfo(in_pktinfo)

Available on crate feature net only.

Ipv6PacketInfo(in6_pktinfo)

Available on crate feature net only.

Ipv4RecvIf(sockaddr_dl)

Available on crate feature net only.

Ipv4RecvDstAddr(in_addr)

Available on crate feature net only.

Trait Implementations

impl Clone for ControlMessageOwned

fn clone(&self) -> ControlMessageOwned

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ControlMessageOwned

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq<ControlMessageOwned> for ControlMessageOwned

fn eq(&self, other: &ControlMessageOwned) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for ControlMessageOwned

impl StructuralEq for ControlMessageOwned

impl StructuralPartialEq for ControlMessageOwned