359 lines
9.7 KiB
Rust
359 lines
9.7 KiB
Rust
use std::collections::{HashMap, VecDeque};
|
|
use std::fmt::Write;
|
|
use std::sync::Arc;
|
|
|
|
use log::trace;
|
|
|
|
use futures::{AsyncReadExt, AsyncWriteExt};
|
|
use kuska_handshake::async_std::BoxStreamWrite;
|
|
|
|
use tokio::sync::mpsc;
|
|
|
|
use async_trait::async_trait;
|
|
|
|
use crate::error::*;
|
|
|
|
/// Priority of a request (click to read more about priorities).
|
|
///
|
|
/// This priority value is used to priorize messages
|
|
/// in the send queue of the client, and their responses in the send queue of the
|
|
/// server. Lower values mean higher priority.
|
|
///
|
|
/// This mechanism is usefull for messages bigger than the maximum chunk size
|
|
/// (set at `0x4000` bytes), such as large file transfers.
|
|
/// In such case, all of the messages in the send queue with the highest priority
|
|
/// will take turns to send individual chunks, in a round-robin fashion.
|
|
/// Once all highest priority messages are sent successfully, the messages with
|
|
/// the next highest priority will begin being sent in the same way.
|
|
///
|
|
/// The same priority value is given to a request and to its associated response.
|
|
pub type RequestPriority = u8;
|
|
|
|
/// Priority class: high
|
|
pub const PRIO_HIGH: RequestPriority = 0x20;
|
|
/// Priority class: normal
|
|
pub const PRIO_NORMAL: RequestPriority = 0x40;
|
|
/// Priority class: background
|
|
pub const PRIO_BACKGROUND: RequestPriority = 0x80;
|
|
/// Priority: primary among given class
|
|
pub const PRIO_PRIMARY: RequestPriority = 0x00;
|
|
/// Priority: secondary among given class (ex: `PRIO_HIGH | PRIO_SECONDARY`)
|
|
pub const PRIO_SECONDARY: RequestPriority = 0x01;
|
|
|
|
// Messages are sent by chunks
|
|
// Chunk format:
|
|
// - u32 BE: request id (same for request and response)
|
|
// - u16 BE: chunk length, possibly with CHUNK_HAS_CONTINUATION flag
|
|
// when this is not the last chunk of the message
|
|
// - [u8; chunk_length] chunk data
|
|
|
|
pub(crate) type RequestID = u32;
|
|
type ChunkLength = u16;
|
|
const MAX_CHUNK_LENGTH: ChunkLength = 0x4000;
|
|
const CHUNK_HAS_CONTINUATION: ChunkLength = 0x8000;
|
|
|
|
struct SendQueueItem {
|
|
id: RequestID,
|
|
prio: RequestPriority,
|
|
data: Vec<u8>,
|
|
cursor: usize,
|
|
}
|
|
|
|
struct SendQueue {
|
|
items: VecDeque<(u8, VecDeque<SendQueueItem>)>,
|
|
}
|
|
|
|
impl SendQueue {
|
|
fn new() -> Self {
|
|
Self {
|
|
items: VecDeque::with_capacity(64),
|
|
}
|
|
}
|
|
fn push(&mut self, item: SendQueueItem) {
|
|
let prio = item.prio;
|
|
let pos_prio = match self.items.binary_search_by(|(p, _)| p.cmp(&prio)) {
|
|
Ok(i) => i,
|
|
Err(i) => {
|
|
self.items.insert(i, (prio, VecDeque::new()));
|
|
i
|
|
}
|
|
};
|
|
self.items[pos_prio].1.push_back(item);
|
|
}
|
|
fn pop(&mut self) -> Option<SendQueueItem> {
|
|
match self.items.pop_front() {
|
|
None => None,
|
|
Some((prio, mut items_at_prio)) => {
|
|
let ret = items_at_prio.pop_front();
|
|
if !items_at_prio.is_empty() {
|
|
self.items.push_front((prio, items_at_prio));
|
|
}
|
|
ret.or_else(|| self.pop())
|
|
}
|
|
}
|
|
}
|
|
fn is_empty(&self) -> bool {
|
|
self.items.iter().all(|(_k, v)| v.is_empty())
|
|
}
|
|
fn dump(&self) -> String {
|
|
let mut ret = String::new();
|
|
for (prio, q) in self.items.iter() {
|
|
for item in q.iter() {
|
|
write!(
|
|
&mut ret,
|
|
" [{} {} ({})]",
|
|
prio,
|
|
item.data.len() - item.cursor,
|
|
item.id
|
|
)
|
|
.unwrap();
|
|
}
|
|
}
|
|
ret
|
|
}
|
|
}
|
|
|
|
/// The SendLoop trait, which is implemented both by the client and the server
|
|
/// connection objects (ServerConna and ClientConn) adds a method `.send_loop()`
|
|
/// that takes a channel of messages to send and an asynchronous writer,
|
|
/// and sends messages from the channel to the async writer, putting them in a queue
|
|
/// before being sent and doing the round-robin sending strategy.
|
|
///
|
|
/// The `.send_loop()` exits when the sending end of the channel is closed,
|
|
/// or if there is an error at any time writing to the async writer.
|
|
#[async_trait]
|
|
pub(crate) trait SendLoop: Sync {
|
|
async fn send_loop<W>(
|
|
self: Arc<Self>,
|
|
mut msg_recv: mpsc::UnboundedReceiver<(RequestID, RequestPriority, Vec<u8>)>,
|
|
mut write: BoxStreamWrite<W>,
|
|
debug_name: String,
|
|
) -> Result<(), Error>
|
|
where
|
|
W: AsyncWriteExt + Unpin + Send + Sync,
|
|
{
|
|
let mut sending = SendQueue::new();
|
|
let mut should_exit = false;
|
|
while !should_exit || !sending.is_empty() {
|
|
trace!("send_loop({}): queue = {}", debug_name, sending.dump());
|
|
if let Ok((id, prio, data)) = msg_recv.try_recv() {
|
|
trace!(
|
|
"send_loop({}): new message to send, id = {}, prio = {}, {} bytes",
|
|
debug_name,
|
|
id,
|
|
prio,
|
|
data.len()
|
|
);
|
|
sending.push(SendQueueItem {
|
|
id,
|
|
prio,
|
|
data,
|
|
cursor: 0,
|
|
});
|
|
} else if let Some(mut item) = sending.pop() {
|
|
trace!(
|
|
"send_loop({}): sending bytes for {} ({} bytes, {} already sent)",
|
|
debug_name,
|
|
item.id,
|
|
item.data.len(),
|
|
item.cursor
|
|
);
|
|
let header_id = RequestID::to_be_bytes(item.id);
|
|
write.write_all(&header_id[..]).await?;
|
|
|
|
if item.data.len() - item.cursor > MAX_CHUNK_LENGTH as usize {
|
|
let size_header =
|
|
ChunkLength::to_be_bytes(MAX_CHUNK_LENGTH | CHUNK_HAS_CONTINUATION);
|
|
write.write_all(&size_header[..]).await?;
|
|
|
|
let new_cursor = item.cursor + MAX_CHUNK_LENGTH as usize;
|
|
write.write_all(&item.data[item.cursor..new_cursor]).await?;
|
|
item.cursor = new_cursor;
|
|
|
|
sending.push(item);
|
|
} else {
|
|
let send_len = (item.data.len() - item.cursor) as ChunkLength;
|
|
|
|
let size_header = ChunkLength::to_be_bytes(send_len);
|
|
write.write_all(&size_header[..]).await?;
|
|
|
|
write.write_all(&item.data[item.cursor..]).await?;
|
|
}
|
|
write.flush().await?;
|
|
} else {
|
|
let sth = msg_recv.recv().await;
|
|
if let Some((id, prio, data)) = sth {
|
|
trace!(
|
|
"send_loop({}): new message to send, id = {}, prio = {}, {} bytes",
|
|
debug_name,
|
|
id,
|
|
prio,
|
|
data.len()
|
|
);
|
|
sending.push(SendQueueItem {
|
|
id,
|
|
prio,
|
|
data,
|
|
cursor: 0,
|
|
});
|
|
} else {
|
|
should_exit = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
let _ = write.goodbye().await;
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// The RecvLoop trait, which is implemented both by the client and the server
|
|
/// connection objects (ServerConn and ClientConn) adds a method `.recv_loop()`
|
|
/// and a prototype of a handler for received messages `.recv_handler()` that
|
|
/// must be filled by implementors. `.recv_loop()` receives messages in a loop
|
|
/// according to the protocol defined above: chunks of message in progress of being
|
|
/// received are stored in a buffer, and when the last chunk of a message is received,
|
|
/// the full message is passed to the receive handler.
|
|
#[async_trait]
|
|
pub(crate) trait RecvLoop: Sync + 'static {
|
|
fn recv_handler(self: &Arc<Self>, id: RequestID, msg: Vec<u8>);
|
|
|
|
async fn recv_loop<R>(self: Arc<Self>, mut read: R, debug_name: String) -> Result<(), Error>
|
|
where
|
|
R: AsyncReadExt + Unpin + Send + Sync,
|
|
{
|
|
let mut receiving = HashMap::new();
|
|
loop {
|
|
let mut header_id = [0u8; RequestID::BITS as usize / 8];
|
|
match read.read_exact(&mut header_id[..]).await {
|
|
Ok(_) => (),
|
|
Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => break,
|
|
Err(e) => return Err(e.into()),
|
|
};
|
|
let id = RequestID::from_be_bytes(header_id);
|
|
|
|
let mut header_size = [0u8; ChunkLength::BITS as usize / 8];
|
|
read.read_exact(&mut header_size[..]).await?;
|
|
let size = ChunkLength::from_be_bytes(header_size);
|
|
trace!(
|
|
"recv_loop({}): got header id = {}, size = 0x{:04x} ({} bytes)",
|
|
debug_name,
|
|
id,
|
|
size,
|
|
size & !CHUNK_HAS_CONTINUATION
|
|
);
|
|
|
|
let has_cont = (size & CHUNK_HAS_CONTINUATION) != 0;
|
|
let size = size & !CHUNK_HAS_CONTINUATION;
|
|
|
|
let mut next_slice = vec![0; size as usize];
|
|
read.read_exact(&mut next_slice[..]).await?;
|
|
trace!("recv_loop({}): read {} bytes", debug_name, next_slice.len());
|
|
|
|
let mut msg_bytes: Vec<_> = receiving.remove(&id).unwrap_or_default();
|
|
msg_bytes.extend_from_slice(&next_slice[..]);
|
|
|
|
if has_cont {
|
|
receiving.insert(id, msg_bytes);
|
|
} else {
|
|
self.recv_handler(id, msg_bytes);
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn test_priority_queue() {
|
|
let i1 = SendQueueItem {
|
|
id: 1,
|
|
prio: PRIO_NORMAL,
|
|
data: vec![],
|
|
cursor: 0,
|
|
};
|
|
let i2 = SendQueueItem {
|
|
id: 2,
|
|
prio: PRIO_HIGH,
|
|
data: vec![],
|
|
cursor: 0,
|
|
};
|
|
let i2bis = SendQueueItem {
|
|
id: 20,
|
|
prio: PRIO_HIGH,
|
|
data: vec![],
|
|
cursor: 0,
|
|
};
|
|
let i3 = SendQueueItem {
|
|
id: 3,
|
|
prio: PRIO_HIGH | PRIO_SECONDARY,
|
|
data: vec![],
|
|
cursor: 0,
|
|
};
|
|
let i4 = SendQueueItem {
|
|
id: 4,
|
|
prio: PRIO_BACKGROUND | PRIO_SECONDARY,
|
|
data: vec![],
|
|
cursor: 0,
|
|
};
|
|
let i5 = SendQueueItem {
|
|
id: 5,
|
|
prio: PRIO_BACKGROUND | PRIO_PRIMARY,
|
|
data: vec![],
|
|
cursor: 0,
|
|
};
|
|
|
|
let mut q = SendQueue::new();
|
|
|
|
q.push(i1); // 1
|
|
let a = q.pop().unwrap(); // empty -> 1
|
|
assert_eq!(a.id, 1);
|
|
assert!(q.pop().is_none());
|
|
|
|
q.push(a); // 1
|
|
q.push(i2); // 2 1
|
|
q.push(i2bis); // [2 20] 1
|
|
let a = q.pop().unwrap(); // 20 1 -> 2
|
|
assert_eq!(a.id, 2);
|
|
let b = q.pop().unwrap(); // 1 -> 20
|
|
assert_eq!(b.id, 20);
|
|
let c = q.pop().unwrap(); // empty -> 1
|
|
assert_eq!(c.id, 1);
|
|
assert!(q.pop().is_none());
|
|
|
|
q.push(a); // 2
|
|
q.push(b); // [2 20]
|
|
q.push(c); // [2 20] 1
|
|
q.push(i3); // [2 20] 3 1
|
|
q.push(i4); // [2 20] 3 1 4
|
|
q.push(i5); // [2 20] 3 1 5 4
|
|
|
|
let a = q.pop().unwrap(); // 20 3 1 5 4 -> 2
|
|
assert_eq!(a.id, 2);
|
|
q.push(a); // [20 2] 3 1 5 4
|
|
|
|
let a = q.pop().unwrap(); // 2 3 1 5 4 -> 20
|
|
assert_eq!(a.id, 20);
|
|
let b = q.pop().unwrap(); // 3 1 5 4 -> 2
|
|
assert_eq!(b.id, 2);
|
|
q.push(b); // 2 3 1 5 4
|
|
let b = q.pop().unwrap(); // 3 1 5 4 -> 2
|
|
assert_eq!(b.id, 2);
|
|
let c = q.pop().unwrap(); // 1 5 4 -> 3
|
|
assert_eq!(c.id, 3);
|
|
q.push(b); // 2 1 5 4
|
|
let b = q.pop().unwrap(); // 1 5 4 -> 2
|
|
assert_eq!(b.id, 2);
|
|
let e = q.pop().unwrap(); // 5 4 -> 1
|
|
assert_eq!(e.id, 1);
|
|
let f = q.pop().unwrap(); // 4 -> 5
|
|
assert_eq!(f.id, 5);
|
|
let g = q.pop().unwrap(); // empty -> 4
|
|
assert_eq!(g.id, 4);
|
|
assert!(q.pop().is_none());
|
|
}
|
|
}
|