Struct Capabilities

#[non_exhaustive]
pub struct Capabilities {
    pub max_transmission_unit: usize,
    pub max_burst_size: Option<usize>,
    pub checksum: ChecksumCapabilities,
}

A description of device capabilities.

Higher-level protocols may achieve higher throughput or lower latency if they consider the bandwidth or packet size limitations.

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.

max_transmission_unit: usize

Maximum transmission unit.

The network device is unable to send or receive frames larger than the value returned by this function.

For Ethernet devices, this is the maximum Ethernet frame size, including the Ethernet header (14 octets), but not including the Ethernet FCS (4 octets). Therefore, Ethernet MTU = IP MTU + 14.

Note that in Linux and other OSes, “MTU” is the IP MTU, not the Ethernet MTU, even for Ethernet devices. This is a common source of confusion.

Most common IP MTU is 1500. Minimum is 576 (for IPv4) or 1280 (for IPv6). Maximum is 9216 octets.

max_burst_size: Option<usize>

Maximum burst size, in terms of MTU.

The network device is unable to send or receive bursts large than the value returned by this function.

If None, there is no fixed limit on burst size, e.g. if network buffers are dynamically allocated.

checksum: ChecksumCapabilities

Checksum behavior.

If the network device is capable of verifying or computing checksums for some protocols, it can request that the stack not do so in software to improve performance.

Trait Implementations

impl Clone for Capabilities

fn clone(&self) -> Capabilities

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Capabilities

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

Formats the value using the given formatter.

impl Default for Capabilities

fn default() -> Capabilities

Returns the “default value” for a type.

impl Format for Capabilities

where Option<usize>: Format, ChecksumCapabilities: Format,

fn format(&self, f: Formatter<'_>)

Writes the defmt representation of self to fmt.