105 lines
2.8 KiB
Rust
105 lines
2.8 KiB
Rust
use std::cell::RefCell;
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use std::vec::Vec;
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use std::rc::Rc;
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use std::io;
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use std::os::unix::io::{RawFd, AsRawFd};
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use crate::Result;
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use crate::phy::{self, sys, DeviceCapabilities, Device};
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use crate::time::Instant;
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/// A virtual Ethernet interface.
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#[derive(Debug)]
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pub struct TapInterface {
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lower: Rc<RefCell<sys::TapInterfaceDesc>>,
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mtu: usize
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}
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impl AsRawFd for TapInterface {
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fn as_raw_fd(&self) -> RawFd {
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self.lower.borrow().as_raw_fd()
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}
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}
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impl TapInterface {
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/// Attaches to a TAP interface called `name`, or creates it if it does not exist.
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///
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/// If `name` is a persistent interface configured with UID of the current user,
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/// no special privileges are needed. Otherwise, this requires superuser privileges
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/// or a corresponding capability set on the executable.
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pub fn new(name: &str) -> io::Result<TapInterface> {
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let mut lower = sys::TapInterfaceDesc::new(name)?;
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lower.attach_interface()?;
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let mtu = lower.interface_mtu()?;
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Ok(TapInterface {
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lower: Rc::new(RefCell::new(lower)),
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mtu: mtu
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})
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}
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}
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impl<'a> Device<'a> for TapInterface {
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type RxToken = RxToken;
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type TxToken = TxToken;
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fn capabilities(&self) -> DeviceCapabilities {
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DeviceCapabilities {
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max_transmission_unit: self.mtu,
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..DeviceCapabilities::default()
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}
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}
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fn receive(&'a mut self) -> Option<(Self::RxToken, Self::TxToken)> {
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let mut lower = self.lower.borrow_mut();
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let mut buffer = vec![0; self.mtu];
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match lower.recv(&mut buffer[..]) {
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Ok(size) => {
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buffer.resize(size, 0);
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let rx = RxToken { buffer };
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let tx = TxToken { lower: self.lower.clone() };
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Some((rx, tx))
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}
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Err(ref err) if err.kind() == io::ErrorKind::WouldBlock => {
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None
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}
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Err(err) => panic!("{}", err)
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}
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}
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fn transmit(&'a mut self) -> Option<Self::TxToken> {
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Some(TxToken {
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lower: self.lower.clone(),
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})
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}
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}
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#[doc(hidden)]
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pub struct RxToken {
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buffer: Vec<u8>
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}
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impl phy::RxToken for RxToken {
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fn consume<R, F>(mut self, _timestamp: Instant, f: F) -> Result<R>
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where F: FnOnce(&mut [u8]) -> Result<R>
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{
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f(&mut self.buffer[..])
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}
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}
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#[doc(hidden)]
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pub struct TxToken {
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lower: Rc<RefCell<sys::TapInterfaceDesc>>,
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}
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impl phy::TxToken for TxToken {
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fn consume<R, F>(self, _timestamp: Instant, len: usize, f: F) -> Result<R>
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where F: FnOnce(&mut [u8]) -> Result<R>
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{
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let mut lower = self.lower.borrow_mut();
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let mut buffer = vec![0; len];
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let result = f(&mut buffer);
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lower.send(&buffer[..]).unwrap();
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result
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}
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}
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