//! Access to networking hardware.
//!
//! The `phy` module deals with the *network devices*. It provides a trait
//! for transmitting and receiving frames, [Device](trait.Device.html)
//! and implementations of it:
//!
//! * the [_loopback_](struct.Loopback.html), for zero dependency testing;
//! * _middleware_ [Tracer](struct.Tracer.html) and
//! [FaultInjector](struct.FaultInjector.html), to facilitate debugging;
//! * _adapters_ [RawSocket](struct.RawSocket.html) and
//! [TapInterface](struct.TapInterface.html), to transmit and receive frames
//! on the host OS.
//!
// https://github.com/rust-lang/rust/issues/38740
//!
//!
//! An implementation of the [Device](trait.Device.html) trait for a simple hardware
//! Ethernet controller could look as follows:
//!
/*!
```rust
use std::slice;
use smoltcp::Error;
use smoltcp::phy::{DeviceLimits, Device};
const TX_BUFFERS: [*mut u8; 2] = [0x10000000 as *mut u8, 0x10001000 as *mut u8];
const RX_BUFFERS: [*mut u8; 2] = [0x10002000 as *mut u8, 0x10003000 as *mut u8];
fn rx_full() -> bool {
/* platform-specific code to check if an incoming packet has arrived */
false
}
fn rx_setup(_buf: *mut u8, _length: &mut usize) {
/* platform-specific code to receive a packet into a buffer */
}
fn tx_empty() -> bool {
/* platform-specific code to check if an outgoing packet can be sent */
false
}
fn tx_setup(_buf: *const u8, _length: usize) {
/* platform-specific code to send a buffer with a packet */
}
# #[allow(dead_code)]
pub struct EthernetDevice {
tx_next: usize,
rx_next: usize
}
impl Device for EthernetDevice {
type RxBuffer = &'static [u8];
type TxBuffer = EthernetTxBuffer;
fn limits(&self) -> DeviceLimits {
let mut limits = DeviceLimits::default();
limits.max_transmission_unit = 1536;
limits.max_burst_size = Some(2);
limits
}
fn receive(&mut self, _timestamp: u64) -> Result {
if rx_full() {
let index = self.rx_next;
self.rx_next = (self.rx_next + 1) % RX_BUFFERS.len();
let mut length = 0;
rx_setup(RX_BUFFERS[self.rx_next], &mut length);
Ok(unsafe {
slice::from_raw_parts(RX_BUFFERS[index], length)
})
} else {
Err(Error::Exhausted)
}
}
fn transmit(&mut self, _timestamp: u64, length: usize) -> Result {
if tx_empty() {
let index = self.tx_next;
self.tx_next = (self.tx_next + 1) % TX_BUFFERS.len();
Ok(EthernetTxBuffer(unsafe {
slice::from_raw_parts_mut(TX_BUFFERS[index], length)
}))
} else {
Err(Error::Exhausted)
}
}
}
pub struct EthernetTxBuffer(&'static mut [u8]);
impl AsRef<[u8]> for EthernetTxBuffer {
fn as_ref(&self) -> &[u8] { self.0 }
}
impl AsMut<[u8]> for EthernetTxBuffer {
fn as_mut(&mut self) -> &mut [u8] { self.0 }
}
impl Drop for EthernetTxBuffer {
fn drop(&mut self) { tx_setup(self.0.as_ptr(), self.0.len()) }
}
```
*/
use Error;
#[cfg(any(feature = "raw_socket", feature = "tap_interface"))]
mod sys;
mod tracer;
mod fault_injector;
mod pcap_writer;
#[cfg(any(feature = "std", feature = "collections"))]
mod loopback;
#[cfg(feature = "raw_socket")]
mod raw_socket;
#[cfg(all(feature = "tap_interface", target_os = "linux"))]
mod tap_interface;
pub use self::tracer::Tracer;
pub use self::fault_injector::FaultInjector;
pub use self::pcap_writer::{PcapLinkType, PcapMode, PcapSink, PcapWriter};
#[cfg(any(feature = "std", feature = "collections"))]
pub use self::loopback::Loopback;
#[cfg(any(feature = "raw_socket"))]
pub use self::raw_socket::RawSocket;
#[cfg(all(feature = "tap_interface", target_os = "linux"))]
pub use self::tap_interface::TapInterface;
/// A tracer device for Ethernet frames.
pub type EthernetTracer = Tracer>;
/// A description of device limitations.
///
/// Higher-level protocols may achieve higher throughput or lower latency if they consider
/// the bandwidth or packet size limitations.
#[derive(Debug, Clone, Default)]
pub struct DeviceLimits {
/// Maximum transmission unit.
///
/// The network device is unable to send or receive frames larger than the value returned
/// by this function.
///
/// For Ethernet, MTU will fall between 576 (for IPv4) or 1280 (for IPv6) and 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,
/// Only present to prevent people from trying to initialize every field of DeviceLimits,
/// which would not let us add new fields in the future.
dummy: ()
}
/// An interface for sending and receiving raw network frames.
///
/// It is expected that a `Device` implementation would allocate memory for both sending
/// and receiving packets from memory pools; hence, the stack borrows the buffer for a packet
/// that it is about to receive, as well for a packet that it is about to send, from the device.
pub trait Device {
type RxBuffer: AsRef<[u8]>;
type TxBuffer: AsRef<[u8]> + AsMut<[u8]>;
/// Get a description of device limitations.
fn limits(&self) -> DeviceLimits;
/// Receive a frame.
///
/// It is expected that a `receive` implementation, once a packet is written to memory
/// through DMA, would gain ownership of the underlying buffer, provide it for parsing,
/// and return it to the network device once it is dropped.
fn receive(&mut self, timestamp: u64) -> Result;
/// Transmit a frame.
///
/// It is expected that a `transmit` implementation would gain ownership of a buffer with
/// the requested length, provide it for emission, and schedule it to be read from
/// memory by the network device once it is dropped.
fn transmit(&mut self, timestamp: u64, length: usize) -> Result;
}