Enum ControlMessage

#[non_exhaustive]
pub enum ControlMessage<'a> {
    ScmRights(&'a [RawFd]),
    ScmCredentials(&'a UnixCredentials),
    AlgSetIv(&'a [u8]),
    AlgSetOp(&'a c_int),
    AlgSetAeadAssoclen(&'a u32),
    RxqOvfl(&'a u32),
    TxTime(&'a u64),
}

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

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.

AlgSetIv(&'a [u8])

Set IV for AF_ALG crypto API.

For further information, please refer to the documentation

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

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

RxqOvfl(&'a u32)

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

TxTime(&'a u64)

Configure the transmission time of packets.

For further information, please refer to the tc-etf(8) man page.

Implementations

impl ControlMessage<'_>

fn space(&self) -> usize

The value of CMSG_SPACE on this message. Safe because CMSG_SPACE is always safe

fn cmsg_len(&self) -> usize

The value of CMSG_LEN on this message. Safe because CMSG_LEN is always safe

fn copy_to_cmsg_data(&self, cmsg_data: *mut u8)

Return a reference to the payload data as a byte pointer

fn len(&self) -> usize

The size of the payload, excluding its cmsghdr

fn cmsg_level(&self) -> c_int

Returns the value to put into the cmsg_level field of the header.

fn cmsg_type(&self) -> c_int

Returns the value to put into the cmsg_type field of the header.

unsafe fn encode_into(&self, cmsg: *mut cmsghdr)

Trait Implementations

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

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

Returns a duplicate 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 for ControlMessage<'a>

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

Tests for self and other values to be equal, and is used by ==.

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

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

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

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

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