nal: Prevent looping until the stack successfully connects to remote

* `NetworkStack::connect()`:
  * Add timeout for connection attempt
  * Now returns the socket at TCP ESTABLISHED or CLOSED states, or after connection timeout
* Split `NetworkStack::update()` into `update()` (for controlling the clock) and `poll()` (for polling the smoltcp EthernetInterface)
* Also remove option `auto_time_update`; the main application is responsible for what values `embedded_time::clock::Clock::try_now()` should return
This commit is contained in:
Harry Ho 2021-03-05 13:27:26 +08:00
parent 6506562c3a
commit d9e50bbcb6
1 changed files with 104 additions and 62 deletions

View File

@ -1,5 +1,5 @@
use core::cell::RefCell;
use core::convert::TryFrom;
use core::convert::TryInto;
use heapless::{consts, Vec};
use embedded_nal as nal;
use nal::nb;
@ -40,7 +40,8 @@ where
unused_handles: RefCell<Vec<net::socket::SocketHandle, consts::U16>>,
time_ms: RefCell<u32>,
last_update_instant: RefCell<Option<time::Instant<IntClock>>>,
clock: IntClock
clock: IntClock,
connection_timeout_ms: u32,
}
impl<'a, SPI, NSS, IntClock> NetworkStack<'a, SPI, NSS, IntClock>
@ -49,7 +50,12 @@ where
NSS: OutputPin,
IntClock: time::Clock<T = u32>,
{
pub fn new(interface: NetworkInterface<SPI, NSS>, sockets: net::socket::SocketSet<'a>, clock: IntClock) -> Self {
pub fn new(
interface: NetworkInterface<SPI, NSS>,
sockets: net::socket::SocketSet<'a>,
clock: IntClock,
connection_timeout_ms: u32,
) -> Self {
let mut unused_handles: Vec<net::socket::SocketHandle, consts::U16> = Vec::new();
for socket in sockets.iter() {
unused_handles.push(socket.handle()).unwrap();
@ -62,34 +68,55 @@ where
time_ms: RefCell::new(0),
last_update_instant: RefCell::new(None),
clock,
connection_timeout_ms,
}
}
// Include auto_time_update to allow Instant::now() to not be called
// Instant::now() is not safe to call in `init()` context
pub fn update(&self, auto_time_update: bool) -> Result<bool, NetworkError> {
if auto_time_update {
// Check if it is the first time the stack has updated the time itself
let now = match *self.last_update_instant.borrow() {
// If it is the first time, do not advance time
// Simply store the current instant to initiate time updating
None => self.clock.try_now().map_err(|_| NetworkError::TimeFault)?,
// If it was updated before, advance time and update last_update_instant
Some(instant) => {
// Calculate elapsed time
let now = self.clock.try_now().map_err(|_| NetworkError::TimeFault)?;
let duration = now.checked_duration_since(&instant).ok_or(NetworkError::TimeFault)?;
let duration_ms = time::duration::Milliseconds::<u32>::try_from(duration).map_err(|_| NetworkError::TimeFault)?;
// Adjust duration into ms (note: decimal point truncated)
self.advance_time(*duration_ms.integer());
now
// Initiate or advance the timer, and return the duration in ms as u32.
fn update(&self) -> Result<u32, NetworkError> {
let mut duration_ms: u32 = 0;
// Check if it is the first time the stack has updated the time itself
let now = match *self.last_update_instant.borrow() {
// If it is the first time, do not advance time
// Simply store the current instant to initiate time updating
None => self.clock.try_now().map_err(|_| NetworkError::TimeFault)?,
// If it was updated before, advance time and update last_update_instant
Some(instant) => {
// Calculate elapsed time
let now = self.clock.try_now().map_err(|_| NetworkError::TimeFault)?;
let mut duration = now.checked_duration_since(&instant);
// Normally, the wrapping clock should produce a valid duration.
// However, if `now` is earlier than `instant` (e.g. because the main
// application cannot get a valid epoch time during initialisation,
// we should still produce a duration that is just 1ms.
if duration.is_none() {
self.time_ms.replace(0);
duration = Some(Milliseconds(1_u32)
.to_generic::<u32>(IntClock::SCALING_FACTOR)
.map_err(|_| NetworkError::TimeFault)?);
}
};
self.last_update_instant.replace(Some(now));
}
let duration_ms_time: Milliseconds<u32> = duration.unwrap().try_into()
.map_err(|_| NetworkError::TimeFault)?;
duration_ms = *duration_ms_time.integer();
// Adjust duration into ms (note: decimal point truncated)
self.advance_time(duration_ms);
now
}
};
self.last_update_instant.replace(Some(now));
Ok(duration_ms)
}
fn advance_time(&self, duration_ms: u32) {
let time = self.time_ms.borrow().wrapping_add(duration_ms);
self.time_ms.replace(time);
}
// Poll on the smoltcp interface
fn poll(&self) -> Result<bool, NetworkError> {
match self.network_interface.borrow_mut().poll(
&mut self.sockets.borrow_mut(),
net::time::Instant::from_millis(*self.time_ms.borrow() as i64),
net::time::Instant::from_millis(*self.time_ms.borrow() as u32),
) {
Ok(changed) => Ok(!changed),
Err(_e) => {
@ -98,11 +125,6 @@ where
}
}
pub fn advance_time(&self, duration: u32) {
let time = self.time_ms.try_borrow().unwrap().wrapping_add(duration);
self.time_ms.replace(time);
}
fn get_ephemeral_port(&self) -> u16 {
// Get the next ephemeral port
let current_port = self.next_port.borrow().clone();
@ -132,20 +154,27 @@ where
}
}
// Ideally connect is only to be performed in `init()` of `main.rs`
// Calling `Instant::now()` of `rtic::cyccnt` would face correctness issue during `init()`
fn connect(
&self,
socket: Self::TcpSocket,
remote: nal::SocketAddr,
) -> Result<Self::TcpSocket, Self::Error> {
let address = {
{
// If the socket has already been connected, ignore the connection
// request silently.
let mut sockets = self.sockets.borrow_mut();
let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(socket);
// If we're already in the process of connecting, ignore the request silently.
if internal_socket.is_open() {
return Ok(socket);
if internal_socket.state() == net::socket::TcpState::Established {
return Ok(socket)
}
}
{
let mut sockets = self.sockets.borrow_mut();
let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(socket);
// abort() instead of close() prevents TcpSocket::connect() from
// raising an error
internal_socket.abort();
match remote.ip() {
nal::IpAddr::V4(addr) => {
let address =
@ -154,45 +183,56 @@ where
.connect((address, remote.port()), self.get_ephemeral_port())
.map_err(|_| NetworkError::ConnectionFailure)?;
net::wire::IpAddress::Ipv4(address)
}
},
nal::IpAddr::V6(addr) => {
let address = net::wire::Ipv6Address::from_parts(&addr.segments()[..]);
internal_socket.connect((address, remote.port()), self.get_ephemeral_port())
let address =
net::wire::Ipv6Address::from_parts(&addr.segments()[..]);
internal_socket
.connect((address, remote.port()), self.get_ephemeral_port())
.map_err(|_| NetworkError::ConnectionFailure)?;
net::wire::IpAddress::Ipv6(address)
}
}
};
// Blocking connect
// Loop to wait until the socket is staying established or closed,
// or the connection attempt has timed out.
let mut timeout_ms: u32 = 0;
loop {
match self.is_connected(&socket) {
Ok(true) => break,
_ => {
let mut sockets = self.sockets.borrow_mut();
let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(socket);
// If the connect got ACK->RST, it will end up in Closed TCP state
// Perform reconnection in this case
if internal_socket.state() == net::socket::TcpState::Closed {
internal_socket.close();
internal_socket
.connect((address, remote.port()), self.get_ephemeral_port())
.map_err(|_| NetworkError::ConnectionFailure)?;
}
{
let mut sockets = self.sockets.borrow_mut();
let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(socket);
// TCP state at ESTABLISHED means there is connection, so
// simply return the socket.
if internal_socket.state() == net::socket::TcpState::Established {
return Ok(socket)
}
// TCP state at CLOSED implies that the remote rejected connection;
// In this case, abort the connection, and then return the socket
// for re-connection in the future.
if internal_socket.state() == net::socket::TcpState::Closed {
internal_socket.abort();
// TODO: Return Err(), but would require changes in quartiq/minimq
return Ok(socket)
}
}
// Avoid using Instant::now() and Advance time manually
self.update(false)?;
{
self.advance_time(1);
// Any TCP states other than CLOSED and ESTABLISHED are considered
// "transient", so this function should keep waiting and let smoltcp poll
// (e.g. for handling echo reqeust/reply) at the same time.
timeout_ms += self.update()?;
self.poll()?;
// Time out, and return the socket for re-connection in the future.
if timeout_ms > self.connection_timeout_ms {
// TODO: Return Err(), but would require changes in quartiq/minimq
return Ok(socket)
}
}
Ok(socket)
}
fn is_connected(&self, socket: &Self::TcpSocket) -> Result<bool, Self::Error> {
let mut sockets = self.sockets.borrow_mut();
let socket: &mut net::socket::TcpSocket = &mut *sockets.get(*socket);
Ok(socket.may_send() && socket.may_recv())
let internal_socket: &mut net::socket::TcpSocket = &mut *sockets.get(*socket);
Ok(internal_socket.state() == net::socket::TcpState::Established)
}
fn write(&self, socket: &mut Self::TcpSocket, buffer: &[u8]) -> nb::Result<usize, Self::Error> {
@ -208,7 +248,8 @@ where
Ok(num_bytes) => {
// In case the buffer is filled up, push bytes into ethernet driver
if num_bytes != non_queued_bytes.len() {
self.update(true)?;
self.update()?;
self.poll()?;
}
// Process the unwritten bytes again, if any
non_queued_bytes = &non_queued_bytes[num_bytes..]
@ -225,7 +266,8 @@ where
buffer: &mut [u8],
) -> nb::Result<usize, Self::Error> {
// Enqueue received bytes into the TCP socket buffer
self.update(true)?;
self.update()?;
self.poll()?;
let mut sockets = self.sockets.borrow_mut();
let socket: &mut net::socket::TcpSocket = &mut *sockets.get(*socket);
let result = socket.recv_slice(buffer);