Struct DatagramMetadata 

#[non_exhaustive]
pub struct DatagramMetadata {
    pub len: usize,
    pub original_len: usize,
    pub segment_size: Option<NonZero<usize>>,
    pub peer: SocketAddress,
    pub local: SocketAddress,
    pub original_destination: Option<SocketAddress>,
    pub interface_index: Option<u32>,
    pub ecn: Option<EcnCodepoint>,
    pub timestamp: Option<ReceiveTimestamp>,
    pub truncated: bool,
}

Available on crate features std and udp only.

Metadata associated with one receive buffer.

A buffer normally contains one UDP datagram. When receive coalescing is in use, it can contain several non-empty datagrams separated at segment_size byte boundaries; only the final segment may be shorter. With no truncation, len is the sum of those segment lengths. A zero-length datagram is always represented alone with no segment size.

truncated applies to the entire received socket entry. If it is true, the copied bytes are only an incomplete prefix of the datagram or coalesced group and consumers must discard the whole entry rather than parse partial segments. original_len is the kernel-reported pre-truncation size when the platform makes it available.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

len: usize

Number of bytes copied into the receive buffer.

original_len: usize

Original number of bytes reported by the socket before truncation.

Some platforms cannot report the original size and use len here.

segment_size: Option<NonZero<usize>>

Size of each coalesced datagram except possibly the last.

None represents exactly one datagram, including a zero-length datagram.

peer: SocketAddress

Source address of the datagram.

local: SocketAddress

Effective local address of the socket for this datagram.

On platforms without destination-address ancillary data this can retain an unspecified IP when the socket was bound to a wildcard address.

original_destination: Option<SocketAddress>

Original destination supplied by a transparent-proxy facility, if enabled.

interface_index: Option<u32>

Index of the interface on which the datagram was received.

ecn: Option<EcnCodepoint>

Received ECN codepoint, or None when the platform did not report it.

Some(EcnCodepoint::NotEct) is deliberately distinct from unavailable.

timestamp: Option<ReceiveTimestamp>

Kernel or implementation receive time, including its clock domain.

truncated: bool

Whether the datagram did not fit in the supplied buffer.

Implementations

impl DatagramMetadata

pub const fn empty() -> DatagramMetadata

Construct an empty metadata slot to be filled by a receive operation.

pub fn segment_count(&self) -> usize

Number of complete or partial segment regions in the copied bytes.

This is the actual datagram count only when truncated is false. A truncated entry must be discarded as a whole.

Trait Implementations

impl Clone for DatagramMetadata

fn clone(&self) -> DatagramMetadata

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for DatagramMetadata

impl Debug for DatagramMetadata

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

Formats the value using the given formatter.

impl Default for DatagramMetadata

fn default() -> DatagramMetadata

Returns the “default value” for a type.

impl Eq for DatagramMetadata

impl PartialEq for DatagramMetadata

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for DatagramMetadata