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[ISO-TP] CAN-FD support (#45)
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@pd0wm
pd0wm authored Mar 19, 2024
1 parent a2e95ba commit 74a2f02
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Showing 3 changed files with 146 additions and 35 deletions.
2 changes: 2 additions & 0 deletions scripts/vecu_isotp.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ def forwarding2(pkt):
parser.add_argument("--stmin", type=int, default=0)
parser.add_argument("--bs", type=int, default=0)
parser.add_argument("--padding", type=int, nargs="?", default=None, const=0xaa)
parser.add_argument("--fd", action=argparse.BooleanOptionalAction)

args = parser.parse_args()

Expand All @@ -33,6 +34,7 @@ def forwarding2(pkt):
'stmin': args.stmin,
'padding': args.padding,
'bs': args.bs,
'fd': args.fd,
}

with ISOTPSocket(args.iface, tx_id=args.tx, rx_id=args.rx, **config) as sock1:
Expand Down
148 changes: 114 additions & 34 deletions src/isotp/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,8 +18,7 @@ pub mod error;
pub mod types;

use crate::async_can::AsyncCanAdapter;
use crate::can::Frame;
use crate::can::Identifier;
use crate::can::{Frame, Identifier, DLC_TO_LEN};
use crate::error::Error;
use crate::isotp::constants::FlowStatus;
use crate::isotp::constants::FLOW_SATUS_MASK;
Expand All @@ -33,6 +32,13 @@ use tracing::debug;
use self::types::FlowControlConfig;

const DEFAULT_TIMEOUT_MS: u64 = 100;
const DEFAULT_PADDING_BYTE: u8 = 0xAA;

const CAN_MAX_DLEN: usize = 8;
const CAN_FD_MAX_DLEN: usize = 64;

const ISO_TP_MAX_DLEN: usize = (1 << 12) - 1;
const ISO_TP_FD_MAX_DLEN: usize = (1 << 32) - 1;

/// Configuring passed to the IsoTPAdapter.
#[derive(Debug, Clone, Copy)]
Expand All @@ -43,14 +49,14 @@ pub struct IsoTPConfig {
pub tx_id: Identifier,
/// Receive ID
pub rx_id: Identifier,
/// Transmit Data Length
pub tx_dl: usize,
/// Padding byte (0x00, or more efficient 0xAA). Set to None to disable padding.
pub padding: Option<u8>,
/// Max timeout for receiving a frame
pub timeout: std::time::Duration,
/// Override for Seperation Time (STmin) for transmitted frames
pub separation_time_min: Option<std::time::Duration>,
/// Enable CAN-FD Mode
pub fd: bool,
}

impl IsoTPConfig {
Expand Down Expand Up @@ -83,10 +89,10 @@ impl IsoTPConfig {
bus,
tx_id,
rx_id,
tx_dl: 8,
padding: Some(0xaa),
padding: Some(DEFAULT_PADDING_BYTE),
timeout: std::time::Duration::from_millis(DEFAULT_TIMEOUT_MS),
separation_time_min: None,
fd: false,
}
}
}
Expand All @@ -110,35 +116,94 @@ impl<'a> IsoTPAdapter<'a> {
}

fn pad(&self, data: &mut Vec<u8>) {
// Pad to next valid DLC
if !DLC_TO_LEN.contains(&data.len()) {
let idx = DLC_TO_LEN.iter().position(|&x| x > data.len()).unwrap();
let padding = self.config.padding.unwrap_or(DEFAULT_PADDING_BYTE);
let len = DLC_TO_LEN[idx] - data.len();
data.extend(std::iter::repeat(padding).take(len));
}

// Pad to full length if padding is enabled
if let Some(padding) = self.config.padding {
let len = self.config.tx_dl - data.len();
let len = self.max_can_data_length() - data.len();
data.extend(std::iter::repeat(padding).take(len));
}
}

fn max_can_data_length(&self) -> usize {
if self.config.fd {
CAN_FD_MAX_DLEN
} else {
CAN_MAX_DLEN
}
}

fn max_isotp_data_length(&self) -> usize {
if self.config.fd {
ISO_TP_FD_MAX_DLEN
} else {
ISO_TP_MAX_DLEN
}
}

fn frame(&self, data: &[u8]) -> Result<Frame, Error> {
// Check if the data length is valid
if !DLC_TO_LEN.contains(&data.len()) {
println!("len {}", data.len());
return Err(crate::error::Error::MalformedFrame);
}

let frame = Frame {
bus: self.config.bus,
id: self.config.tx_id,
data: data.to_vec(),
loopback: false,
fd: self.config.fd,
};

Ok(frame)
}
pub async fn send_single_frame(&self, data: &[u8]) -> Result<(), Error> {
let mut buf = vec![FrameType::Single as u8 | data.len() as u8];
let mut buf;

if data.len() < CAN_MAX_DLEN {
buf = vec![FrameType::Single as u8 | data.len() as u8];
} else {
// Use escape sequence for length, length is in the next byte
buf = vec![FrameType::Single as u8, data.len() as u8];
}

buf.extend(data);
self.pad(&mut buf);

debug!("TX SF, length: {} data {}", data.len(), hex::encode(&buf));

let frame = Frame::new(self.config.bus, self.config.tx_id, &buf)?;
let frame = self.frame(&buf)?;
self.adapter.send(&frame).await;
Ok(())
}

pub async fn send_first_frame(&self, data: &[u8]) -> Result<(), Error> {
let b0: u8 = FrameType::First as u8 | ((data.len() >> 8) & 0xF) as u8;
let b1: u8 = (data.len() & 0xFF) as u8;

let mut buf = vec![b0, b1];
buf.extend(&data[..self.config.tx_dl - 2]);
pub async fn send_first_frame(&self, data: &[u8]) -> Result<usize, Error> {
let mut buf;
if data.len() <= ISO_TP_MAX_DLEN {
let b0: u8 = FrameType::First as u8 | ((data.len() >> 8) & 0xF) as u8;
let b1: u8 = (data.len() & 0xFF) as u8;
buf = vec![b0, b1];
} else {
let b0: u8 = FrameType::First as u8;
let b1: u8 = 0x00;
buf = vec![b0, b1];
buf.extend((data.len() as u32).to_be_bytes());
}
let offset = buf.len();
buf.extend(&data[..self.max_can_data_length() - buf.len()]);

debug!("TX FF, length: {} data {}", data.len(), hex::encode(&buf));

let frame = Frame::new(self.config.bus, self.config.tx_id, &buf)?;
let frame = self.frame(&buf)?;
self.adapter.send(&frame).await;
Ok(())
Ok(offset)
}

pub async fn send_consecutive_frame(&self, data: &[u8], idx: usize) -> Result<(), Error> {
Expand All @@ -150,7 +215,8 @@ impl<'a> IsoTPAdapter<'a> {

debug!("TX CF, idx: {} data {}", idx, hex::encode(&buf));

let frame = Frame::new(self.config.bus, self.config.tx_id, &buf)?;
let frame = self.frame(&buf)?;

self.adapter.send(&frame).await;

Ok(())
Expand Down Expand Up @@ -185,7 +251,7 @@ impl<'a> IsoTPAdapter<'a> {
.timeout(self.config.timeout);
tokio::pin!(stream);

self.send_first_frame(data).await?;
let offset = self.send_first_frame(data).await?;
let frame = stream.next().await.unwrap()?;
let mut fc_config = self.receive_flow_control(&frame)?;

Expand All @@ -197,7 +263,8 @@ impl<'a> IsoTPAdapter<'a> {
None => fc_config.separation_time_min,
};

let chunks = data[self.config.tx_dl - 2..].chunks(self.config.tx_dl - 1);
let tx_dl = self.max_can_data_length();
let chunks = data[tx_dl - offset..].chunks(tx_dl - 1);
let mut it = chunks.enumerate().peekable();
while let Some((idx, chunk)) = it.next() {
self.send_consecutive_frame(chunk, idx).await?;
Expand All @@ -223,9 +290,13 @@ impl<'a> IsoTPAdapter<'a> {
pub async fn send(&self, data: &[u8]) -> Result<(), Error> {
debug!("TX {}", hex::encode(data));

if data.len() < self.config.tx_dl {
// Single frame has 1 byte of overhead for CAN, and 2 bytes for CAN-FD with escape sequence
let fits_in_single_frame =
data.len() < CAN_MAX_DLEN || data.len() < self.max_can_data_length() - 1;

if fits_in_single_frame {
self.send_single_frame(data).await?;
} else if data.len() <= 4095 {
} else if data.len() <= self.max_isotp_data_length() {
self.send_multiple(data).await?;
} else {
return Err(crate::isotp::error::Error::DataTooLarge.into());
Expand All @@ -234,45 +305,53 @@ impl<'a> IsoTPAdapter<'a> {
Ok(())
}
async fn recv_single_frame(&self, frame: &Frame) -> Result<Vec<u8>, Error> {
let len = (frame.data[0] & 0xF) as usize;
let mut len = (frame.data[0] & 0xF) as usize;
let mut offset = 1;

// CAN-FD Escape sequence
if len == 0 {
unimplemented!("CAN FD escape sequence for single frame not supported");
len = frame.data[1] as usize;
offset = 2;
}

// Check if the frame contains enough data
if len + 1 > frame.data.len() {
if len + offset > frame.data.len() {
return Err(crate::isotp::error::Error::MalformedFrame.into());
}

debug!("RX SF, length: {} data {}", len, hex::encode(&frame.data));

Ok(frame.data[1..len + 1].to_vec())
Ok(frame.data[offset..len + offset].to_vec())
}

async fn recv_first_frame(&self, frame: &Frame, buf: &mut Vec<u8>) -> Result<usize, Error> {
let b0 = frame.data[0] as u16;
let b1 = frame.data[1] as u16;
let len = ((b0 << 8 | b1) & 0xFFF) as usize;
let mut len = ((b0 << 8 | b1) & 0xFFF) as usize;
let mut offset = 2;

debug!("RX FF, length: {}, data {}", len, hex::encode(&frame.data));
// CAN-FD Escape sequence
if len == 0 {
unimplemented!("CAN FD escape sequence for first frame not supported");
offset = 6;
len = u32::from_be_bytes([frame.data[2], frame.data[3], frame.data[4], frame.data[5]])
as usize;
}
debug!("RX FF, length: {}, data {}", len, hex::encode(&frame.data));

// A FF cannot use CAN frame data optmization, and always needs to be full length.
if frame.data.len() < self.config.tx_dl {
if frame.data.len() < self.max_can_data_length() {
return Err(crate::isotp::error::Error::MalformedFrame.into());
}

buf.extend(&frame.data[2..]);
buf.extend(&frame.data[offset..]);

// Send Flow Control
let mut flow_control = vec![0x30, 0x00, 0x00];
self.pad(&mut flow_control);

debug!("TX FC, data {}", hex::encode(&flow_control));

let frame = Frame::new(self.config.bus, self.config.tx_id, &flow_control)?;
let frame = self.frame(&flow_control)?;
self.adapter.send(&frame).await;

Ok(len)
Expand All @@ -289,9 +368,10 @@ impl<'a> IsoTPAdapter<'a> {
let remaining_len = len - buf.len();

// Only the last consecutive frame can use CAN frame data optimization
if remaining_len >= self.config.tx_dl - 1 {
let tx_dl = self.max_can_data_length();
if remaining_len >= tx_dl - 1 {
// Ensure frame is full length
if frame.data.len() < self.config.tx_dl {
if frame.data.len() < tx_dl {
return Err(crate::isotp::error::Error::MalformedFrame.into());
}
} else {
Expand Down
31 changes: 30 additions & 1 deletion tests/isotp_tests.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,11 +14,12 @@ impl Drop for ChildGuard {
}
}

#[derive(Default, Copy, Clone)]
#[derive(Default, Copy, Clone, Debug)]
struct VECUConfig {
pub stmin: u32,
pub bs: u32,
pub padding: Option<u8>,
pub fd: bool,
}

impl VECUConfig {
Expand All @@ -36,6 +37,10 @@ impl VECUConfig {
result.push(format!("{}", padding));
}

if self.fd {
result.push("--fd".to_owned());
}

result
}
}
Expand Down Expand Up @@ -63,6 +68,7 @@ async fn isotp_test_echo(msg_len: usize, config: VECUConfig) {

let mut isotp_config = IsoTPConfig::new(0, Identifier::Standard(0x7a1));
isotp_config.padding = config.padding;
isotp_config.fd = config.fd;

let isotp = IsoTPAdapter::new(&adapter, isotp_config);

Expand All @@ -71,6 +77,7 @@ async fn isotp_test_echo(msg_len: usize, config: VECUConfig) {
isotp.send(&request).await.unwrap();
let response = stream.next().await.unwrap().unwrap();

assert_eq!(response.len(), request.len());
assert_eq!(response, request);
}

Expand Down Expand Up @@ -135,3 +142,25 @@ async fn isotp_test_bs() {
isotp_test_echo(64, config).await;
}
}

#[cfg(feature = "test_vcan")]
#[tokio::test]
#[serial_test::serial]
async fn isotp_test_fd() {
let config = VECUConfig {
fd: true,
..Default::default()
};

// Single frame escape
isotp_test_echo(62, config).await;

// Single frame with some padding to reach next DLC
isotp_test_echo(50, config).await;

// Multiple frames
isotp_test_echo(256, config).await;

// First frame escape
isotp_test_echo(5000, config).await;
}

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