Enum nix::sys::socket::ControlMessage

#[non_exhaustive]
pub enum ControlMessage<'a> {
    ScmRights(&'a [RawFd]),
    ScmCredentials(&'a UnixCredentials),
    AlgSetIv(&'a [u8]),
    AlgSetOp(&'a c_int),
    AlgSetAeadAssoclen(&'a u32),
    UdpGsoSegments(&'a u16),
    Ipv4PacketInfo(&'a in_pktinfo),
    Ipv6PacketInfo(&'a in6_pktinfo),
    RxqOvfl(&'a u32),
}

A type-safe zero-copy wrapper around a single control message, as used wih sendmsg. More types may be added to this enum; do not exhaustively pattern-match it.

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(&'a [RawFd])

A message of type SCM_RIGHTS, containing an array of file descriptors passed between processes.

See the description in the “Ancillary messages” section of the unix(7) man page.

Using multiple ScmRights messages for a single sendmsg call isn’t recommended since it causes platform-dependent behaviour: It might swallow all but the first ScmRights message or fail with EINVAL. Instead, you can put all fds to be passed into a single ScmRights message.

Tuple Fields of ScmRights

0: &'a [RawFd]

ScmCredentials(&'a UnixCredentials)

A message of type SCM_CREDENTIALS, containing the pid, uid and gid of a process connected to the socket.

This is similar to the socket option SO_PEERCRED, but requires a process to explicitly send its credentials. A process running as root is allowed to specify any credentials, while credentials sent by other processes are verified by the kernel.

For further information, please refer to the unix(7) man page.

Tuple Fields of ScmCredentials

0: &'a UnixCredentials

AlgSetIv(&'a [u8])

Set IV for AF_ALG crypto API.

For further information, please refer to the documentation

Tuple Fields of AlgSetIv

0: &'a [u8]

AlgSetOp(&'a c_int)

Set crypto operation for AF_ALG crypto API. It may be one of ALG_OP_ENCRYPT or ALG_OP_DECRYPT

For further information, please refer to the documentation

Tuple Fields of AlgSetOp

0: &'a c_int

AlgSetAeadAssoclen(&'a u32)

Set the length of associated authentication data (AAD) (applicable only to AEAD algorithms) for AF_ALG crypto API.

For further information, please refer to the documentation

Tuple Fields of AlgSetAeadAssoclen

0: &'a u32

UdpGsoSegments(&'a u16)

UDP GSO makes it possible for applications to generate network packets for a virtual MTU much greater than the real one. The length of the send data no longer matches the expected length on the wire. The size of the datagram payload as it should appear on the wire may be passed through this control message. Send buffer should consist of multiple fixed-size wire payloads following one by one, and the last, possibly smaller one.

Tuple Fields of UdpGsoSegments

0: &'a u16

Ipv4PacketInfo(&'a in_pktinfo)

Configure the sending addressing and interface for v4

For further information, please refer to the ip(7) man page.

Tuple Fields of Ipv4PacketInfo

0: &'a in_pktinfo

Ipv6PacketInfo(&'a in6_pktinfo)

Configure the sending addressing and interface for v6

For further information, please refer to the ipv6(7) man page.

Tuple Fields of Ipv6PacketInfo

0: &'a in6_pktinfo

RxqOvfl(&'a u32)

SO_RXQ_OVFL indicates that an unsigned 32 bit value ancilliary msg (cmsg) should be attached to recieved skbs indicating the number of packets dropped by the socket between the last recieved packet and this received packet.

Tuple Fields of RxqOvfl

0: &'a u32

Trait Implementations

impl<'a> Clone for ControlMessage<'a>

fn clone(&self) -> ControlMessage<'a>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for ControlMessage<'a>

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

Formats the value using the given formatter.

impl<'a> PartialEq<ControlMessage<'a>> for ControlMessage<'a>

fn eq(&self, other: &ControlMessage<'a>) -> bool

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

fn ne(&self, other: &ControlMessage<'a>) -> bool

This method tests for !=.

impl<'a> Copy for ControlMessage<'a>

impl<'a> Eq for ControlMessage<'a>

impl<'a> StructuralEq for ControlMessage<'a>

impl<'a> StructuralPartialEq for ControlMessage<'a>