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#![no_std]
use core::task::Context;
pub trait Driver {
type RxToken<'a>: RxToken
where
Self: 'a;
type TxToken<'a>: TxToken
where
Self: 'a;
fn receive(&mut self, cx: &mut Context) -> Option<(Self::RxToken<'_>, Self::TxToken<'_>)>;
fn transmit(&mut self, cx: &mut Context) -> Option<Self::TxToken<'_>>;
fn link_state(&mut self, cx: &mut Context) -> LinkState;
fn capabilities(&self) -> Capabilities;
fn ethernet_address(&self) -> [u8; 6];
}
impl<T: ?Sized + Driver> Driver for &mut T {
type RxToken<'a> = T::RxToken<'a>
where
Self: 'a;
type TxToken<'a> = T::TxToken<'a>
where
Self: 'a;
fn transmit(&mut self, cx: &mut Context) -> Option<Self::TxToken<'_>> {
T::transmit(self, cx)
}
fn receive(&mut self, cx: &mut Context) -> Option<(Self::RxToken<'_>, Self::TxToken<'_>)> {
T::receive(self, cx)
}
fn capabilities(&self) -> Capabilities {
T::capabilities(self)
}
fn link_state(&mut self, cx: &mut Context) -> LinkState {
T::link_state(self, cx)
}
fn ethernet_address(&self) -> [u8; 6] {
T::ethernet_address(self)
}
}
/// A token to receive a single network packet.
pub trait RxToken {
/// Consumes the token to receive a single network packet.
///
/// This method receives a packet and then calls the given closure `f` with the raw
/// packet bytes as argument.
fn consume<R, F>(self, f: F) -> R
where
F: FnOnce(&mut [u8]) -> R;
}
/// A token to transmit a single network packet.
pub trait TxToken {
/// Consumes the token to send a single network packet.
///
/// This method constructs a transmit buffer of size `len` and calls the passed
/// closure `f` with a mutable reference to that buffer. The closure should construct
/// a valid network packet (e.g. an ethernet packet) in the buffer. When the closure
/// returns, the transmit buffer is sent out.
fn consume<R, F>(self, len: usize, f: F) -> R
where
F: FnOnce(&mut [u8]) -> R;
}
/// A description of device capabilities.
///
/// Higher-level protocols may achieve higher throughput or lower latency if they consider
/// the bandwidth or packet size limitations.
#[derive(Debug, Clone, Default)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
#[non_exhaustive]
pub struct Capabilities {
/// Medium of the device.
///
/// This indicates what kind of packet the sent/received bytes are, and determines
/// some behaviors of Interface. For example, ARP/NDISC address resolution is only done
/// for Ethernet mediums.
pub medium: Medium,
/// 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.
pub max_transmission_unit: 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.
pub max_burst_size: Option<usize>,
/// 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.
pub checksum: ChecksumCapabilities,
}
/// Type of medium of a device.
#[derive(Debug, Eq, PartialEq, Copy, Clone)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub enum Medium {
/// Ethernet medium. Devices of this type send and receive Ethernet frames,
/// and interfaces using it must do neighbor discovery via ARP or NDISC.
///
/// Examples of devices of this type are Ethernet, WiFi (802.11), Linux `tap`, and VPNs in tap (layer 2) mode.
Ethernet,
/// IP medium. Devices of this type send and receive IP frames, without an
/// Ethernet header. MAC addresses are not used, and no neighbor discovery (ARP, NDISC) is done.
///
/// Examples of devices of this type are the Linux `tun`, PPP interfaces, VPNs in tun (layer 3) mode.
Ip,
}
impl Default for Medium {
fn default() -> Medium {
Medium::Ethernet
}
}
/// A description of checksum behavior for every supported protocol.
#[derive(Debug, Clone, Default)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
#[non_exhaustive]
pub struct ChecksumCapabilities {
pub ipv4: Checksum,
pub udp: Checksum,
pub tcp: Checksum,
pub icmpv4: Checksum,
pub icmpv6: Checksum,
}
/// A description of checksum behavior for a particular protocol.
#[derive(Debug, Clone, Copy)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub enum Checksum {
/// Verify checksum when receiving and compute checksum when sending.
Both,
/// Verify checksum when receiving.
Rx,
/// Compute checksum before sending.
Tx,
/// Ignore checksum completely.
None,
}
impl Default for Checksum {
fn default() -> Checksum {
Checksum::Both
}
}
#[derive(PartialEq, Eq, Clone, Copy)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub enum LinkState {
Down,
Up,
}
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