virtio_drivers/device/net/
dev.rs

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1use alloc::vec;
2
3use super::net_buf::{RxBuffer, TxBuffer};
4use super::{EthernetAddress, VirtIONetRaw};
5use crate::{hal::Hal, transport::Transport, Error, Result};
6
7/// Driver for a VirtIO network device.
8///
9/// Unlike [`VirtIONetRaw`], it uses [`RxBuffer`]s for transmission and
10/// reception rather than the raw slices. On initialization, it pre-allocates
11/// all receive buffers and puts them all in the receive queue.
12///
13/// The virtio network device is a virtual ethernet card.
14///
15/// It has enhanced rapidly and demonstrates clearly how support for new
16/// features are added to an existing device.
17/// Empty buffers are placed in one virtqueue for receiving packets, and
18/// outgoing packets are enqueued into another for transmission in that order.
19/// A third command queue is used to control advanced filtering features.
20pub struct VirtIONet<H: Hal, T: Transport, const QUEUE_SIZE: usize> {
21    inner: VirtIONetRaw<H, T, QUEUE_SIZE>,
22    rx_buffers: [Option<RxBuffer>; QUEUE_SIZE],
23}
24
25impl<H: Hal, T: Transport, const QUEUE_SIZE: usize> VirtIONet<H, T, QUEUE_SIZE> {
26    /// Create a new VirtIO-Net driver.
27    pub fn new(transport: T, buf_len: usize) -> Result<Self> {
28        let mut inner = VirtIONetRaw::new(transport)?;
29
30        const NONE_BUF: Option<RxBuffer> = None;
31        let mut rx_buffers = [NONE_BUF; QUEUE_SIZE];
32        for (i, rx_buf_place) in rx_buffers.iter_mut().enumerate() {
33            let mut rx_buf = RxBuffer::new(i, buf_len);
34            // Safe because the buffer lives as long as the queue.
35            let token = unsafe { inner.receive_begin(rx_buf.as_bytes_mut())? };
36            assert_eq!(token, i as u16);
37            *rx_buf_place = Some(rx_buf);
38        }
39
40        Ok(VirtIONet { inner, rx_buffers })
41    }
42
43    /// Acknowledge interrupt.
44    pub fn ack_interrupt(&mut self) -> bool {
45        self.inner.ack_interrupt()
46    }
47
48    /// Disable interrupts.
49    pub fn disable_interrupts(&mut self) {
50        self.inner.disable_interrupts()
51    }
52
53    /// Enable interrupts.
54    pub fn enable_interrupts(&mut self) {
55        self.inner.enable_interrupts()
56    }
57
58    /// Get MAC address.
59    pub fn mac_address(&self) -> EthernetAddress {
60        self.inner.mac_address()
61    }
62
63    /// Whether can send packet.
64    pub fn can_send(&self) -> bool {
65        self.inner.can_send()
66    }
67
68    /// Whether can receive packet.
69    pub fn can_recv(&self) -> bool {
70        self.inner.poll_receive().is_some()
71    }
72
73    /// Receives a [`RxBuffer`] from network. If currently no data, returns an
74    /// error with type [`Error::NotReady`].
75    ///
76    /// It will try to pop a buffer that completed data reception in the
77    /// NIC queue.
78    pub fn receive(&mut self) -> Result<RxBuffer> {
79        if let Some(token) = self.inner.poll_receive() {
80            let mut rx_buf = self.rx_buffers[token as usize]
81                .take()
82                .ok_or(Error::WrongToken)?;
83            if token != rx_buf.idx {
84                return Err(Error::WrongToken);
85            }
86
87            // Safe because `token` == `rx_buf.idx`, we are passing the same
88            // buffer as we passed to `VirtQueue::add` and it is still valid.
89            let (_hdr_len, pkt_len) =
90                unsafe { self.inner.receive_complete(token, rx_buf.as_bytes_mut())? };
91            rx_buf.set_packet_len(pkt_len);
92            Ok(rx_buf)
93        } else {
94            Err(Error::NotReady)
95        }
96    }
97
98    /// Gives back the ownership of `rx_buf`, and recycles it for next use.
99    ///
100    /// It will add the buffer back to the NIC queue.
101    pub fn recycle_rx_buffer(&mut self, mut rx_buf: RxBuffer) -> Result {
102        // Safe because we take the ownership of `rx_buf` back to `rx_buffers`,
103        // it lives as long as the queue.
104        let new_token = unsafe { self.inner.receive_begin(rx_buf.as_bytes_mut()) }?;
105        // `rx_buffers[new_token]` is expected to be `None` since it was taken
106        // away at `Self::receive()` and has not been added back.
107        if self.rx_buffers[new_token as usize].is_some() {
108            return Err(Error::WrongToken);
109        }
110        rx_buf.idx = new_token;
111        self.rx_buffers[new_token as usize] = Some(rx_buf);
112        Ok(())
113    }
114
115    /// Allocate a new buffer for transmitting.
116    pub fn new_tx_buffer(&self, buf_len: usize) -> TxBuffer {
117        TxBuffer(vec![0; buf_len])
118    }
119
120    /// Sends a [`TxBuffer`] to the network, and blocks until the request
121    /// completed.
122    pub fn send(&mut self, tx_buf: TxBuffer) -> Result {
123        self.inner.send(tx_buf.packet())
124    }
125}
virtio_drivers/device/net/dev.rs

virtio_drivers/device/net/
dev.rs
