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use std::net::SocketAddr;
use tokio::net::{TcpStream, TcpListener};
use tokio::stream::StreamExt;
use tokio::sync::mpsc::{self, UnboundedSender, UnboundedReceiver};
use tokio::io::{ReadHalf, WriteHalf, AsyncWriteExt, AsyncReadExt};
use crate::{Request, Response, IORequest, IOResponse, IOResponseInner, IORequestInner};
use std::io::Result;
use protocol::io;
use futures::select;
use futures::future::FutureExt;
mod protocol;
use protocol::handshake::*;
use protocol::consts::*;
use protocol::transmission::reply;
pub use protocol::handshake::Export;
fn strerror(s: &'static str) -> std::io::Result<()> {
Err(std::io::Error::new(std::io::ErrorKind::InvalidData, s))
}
#[derive(serde::Serialize, serde::Deserialize)]
struct Context {
handle: u64,
}
struct RequestHandler {
read_stream: ReadHalf<TcpStream>,
request_tx: UnboundedSender<Request>,
response_tx: UnboundedSender<Response>,
}
impl RequestHandler {
async fn run_once(&mut self) -> Result<()> {
let c = &mut self.read_stream;
let magic = io::read_u32(c).await?;
if magic != 0x25609513 {
strerror("Invalid request magic")?;
}
let _flags = io::read_u16(c).await?;
let typ = io::read_u16(c).await?;
let handle = io::read_u64(c).await?;
let offset = io::read_u64(c).await?;
let length = io::read_u32(c).await?;
let context = Context {
handle,
};
let context = rmp_serde::to_vec(&context).unwrap();
match typ {
NBD_CMD_READ => {
let req = Request {
inner: IORequestInner::IORequest(IORequest::Read {
offset,
length,
}),
tx: self.response_tx.clone(),
context,
};
let _ = self.request_tx.send(req);
},
NBD_CMD_WRITE => {
let mut buf = vec![0; length as usize];
let _ = c.read_exact(&mut buf).await;
let req = Request {
inner: IORequestInner::IORequest(IORequest::Write {
payload: buf,
offset,
length,
fua: false,
}),
tx: self.response_tx.clone(),
context,
};
let _ = self.request_tx.send(req);
},
NBD_CMD_DISC => {
return Ok(())
}
NBD_CMD_FLUSH => {
let req = Request {
inner: IORequestInner::IORequest(IORequest::Flush),
tx: self.response_tx.clone(),
context,
};
let _ = self.request_tx.send(req);
}
NBD_CMD_TRIM | NBD_CMD_WRITE_ZEROES => {
let req = Request {
inner: IORequestInner::Echo(38),
tx: self.response_tx.clone(),
context,
};
let _ = self.request_tx.send(req);
}
_ => {}
}
Ok(())
}
async fn run(mut self) {
loop {
let _ = self.run_once().await;
}
}
}
struct ResponseHandler {
write_stream: WriteHalf<TcpStream>,
response_rx: UnboundedReceiver<Response>,
}
impl ResponseHandler {
async fn run_once(&mut self, resp: Response) -> Result<()> {
let c = &mut self.write_stream;
let context: Context = rmp_serde::from_slice(&resp.context).unwrap();
let handle = context.handle;
match resp.inner {
Ok(IOResponseInner::IOResponse(req)) => {
match req {
IOResponse::Ok => {
reply(c, 0, handle).await?;
},
IOResponse::Read { mut payload } => {
reply(c, 0, handle).await?;
let _ = c.write_all(&mut payload).await;
},
}
}
Ok(IOResponseInner::Echo(n)) => {
let _ = reply(c, n, handle).await;
},
Err(e) => {
let e = e.raw_os_error().unwrap_or(5) as u32;
let _ = reply(c, e, handle).await;
}
}
Ok(())
}
async fn run(mut self) {
while let Some(resp) = self.response_rx.recv().await {
let _ = self.run_once(resp).await;
}
}
}
pub struct Server {
request_tx: UnboundedSender<Request>,
export: Export
}
impl Server {
pub fn new(request_tx: UnboundedSender<Request>, export: Export) -> Self {
Self {
request_tx,
export,
}
}
pub async fn serve(self, socket: SocketAddr) {
let mut listener = TcpListener::bind(socket).await.unwrap();
while let Some(conn) = listener.next().await {
match conn {
Ok(mut stream) => {
match handshake(&mut stream, &self.export).await {
Ok(_) => {
let (read_stream, write_stream) = tokio::io::split(stream);
let (response_tx, response_rx) = mpsc::unbounded_channel::<Response>();
let request_handler = RequestHandler {
read_stream,
request_tx: self.request_tx.clone(),
response_tx,
};
let response_handler = ResponseHandler {
write_stream,
response_rx,
};
let fut = async move {
let mut fut1 = tokio::spawn(request_handler.run()).fuse();
let mut fut2 = tokio::spawn(response_handler.run()).fuse();
select! {
_ = fut1 => {},
_ = fut2 => {},
}
};
tokio::spawn(fut);
},
Err(_) => {}
}
},
Err(_) => {},
}
}
}
}
pub const NBD_DEFAULT_PORT: u16 = 10809;