Rust: integrate lwip with the I/O scheduler.

artiq/runtime.rs/liblwip/lib.rs

@@ -59,11 +59,13 @@ fn result_from<T, F>(err: lwip_sys::err, f: F) -> Result<T>
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub enum IpAddr {
     Ip4([u8;  4]),
-    Ip6([u16; 8])
+    Ip6([u16; 8]),
+    IpAny
 }
 
 pub const IP4_ANY: IpAddr = IpAddr::Ip4([0, 0, 0, 0]);
 pub const IP6_ANY: IpAddr = IpAddr::Ip6([0, 0, 0, 0, 0, 0, 0, 0]);
+pub const IP_ANY: IpAddr = IpAddr::IpAny;
 
 impl IpAddr {
     fn into_raw(self) -> lwip_sys::ip_addr {
@@ -84,6 +86,11 @@ impl IpAddr {
                             (segments[4] as u32) << 16 | (segments[5] as u32),
                             (segments[6] as u32) << 16 | (segments[7] as u32)],
                     type_: lwip_sys::IPADDR_TYPE_V6
+                },
+            IpAddr::IpAny =>
+                lwip_sys::ip_addr {
+                    data:  [0; 4],
+                    type_: lwip_sys::IPADDR_TYPE_ANY
                 }
         }
     }
@@ -100,7 +107,8 @@ impl IpAddr {
                              (data[1] >> 16) as u16, data[1] as u16,
                              (data[2] >> 16) as u16, data[2] as u16,
                              (data[3] >> 16) as u16, data[3] as u16]),
-            _ => panic!("unknown IP address type")
+            lwip_sys::ip_addr { type_: lwip_sys::IPADDR_TYPE_ANY, .. } =>
+                IpAddr::IpAny
         }
     }
 }
@@ -186,10 +194,21 @@ impl<'a> Drop for Pbuf<'a> {
     }
 }
 
+#[derive(Debug)]
+pub struct UdpSocketState {
+    recv_buffer: LinkedList<(SocketAddr, Pbuf<'static>)>
+}
+
+impl UdpSocketState {
+    pub fn readable(&self) -> bool {
+        !self.recv_buffer.is_empty()
+    }
+}
+
 #[derive(Debug)]
 pub struct UdpSocket {
-    raw: *mut lwip_sys::udp_pcb,
-    buffer: Box<LinkedList<(SocketAddr, Pbuf<'static>)>>
+    raw:   *mut lwip_sys::udp_pcb,
+    state: Box<UdpSocketState>
 }
 
 impl UdpSocket {
@@ -198,9 +217,9 @@ impl UdpSocket {
                        pbuf: *mut lwip_sys::pbuf,
                        addr: *mut lwip_sys::ip_addr, port: u16) {
             unsafe {
-                let buffer = arg as *mut LinkedList<(SocketAddr, Pbuf)>;
+                let state = arg as *mut UdpSocketState;
                 let socket_addr = SocketAddr { ip: IpAddr::from_raw(addr), port: port };
-                (*buffer).push_back((socket_addr, Pbuf::from_raw(pbuf)));
+                (*state).recv_buffer.push_back((socket_addr, Pbuf::from_raw(pbuf)));
             }
         }
 
@@ -208,13 +227,17 @@ impl UdpSocket {
             let raw = lwip_sys::udp_new();
             if raw.is_null() { return Err(Error::OutOfMemory) }
 
-            let mut buffer = Box::new(LinkedList::new());
-            let arg = &mut *buffer as *mut LinkedList<(SocketAddr, Pbuf)> as *mut _;
+            let mut state = Box::new(UdpSocketState { recv_buffer: LinkedList::new() });
+            let arg = &mut *state as *mut UdpSocketState as *mut _;
             lwip_sys::udp_recv(raw, recv, arg);
-            Ok(UdpSocket { raw: raw, buffer: buffer })
+            Ok(UdpSocket { raw: raw, state: state })
         }
     }
 
+    pub fn state(&self) -> *const UdpSocketState {
+        &*self.state
+    }
+
     pub fn bind(&mut self, addr: SocketAddr) -> Result<()> {
         result_from(unsafe {
             lwip_sys::udp_bind(self.raw, &mut addr.ip.into_raw(), addr.port)
@@ -247,7 +270,11 @@ impl UdpSocket {
     }
 
     pub fn try_recv(&mut self) -> Option<(SocketAddr, Pbuf<'static>)> {
-        self.buffer.pop_front()
+        self.state.recv_buffer.pop_front()
+    }
+
+    pub fn close(self) {
+        // just drop
     }
 }
 
@@ -257,10 +284,21 @@ impl Drop for UdpSocket {
     }
 }
 
+#[derive(Debug)]
+pub struct TcpListenerState {
+    backlog: LinkedList<TcpStream>
+}
+
+impl TcpListenerState {
+    pub fn acceptable(&self) -> bool {
+        !self.backlog.is_empty()
+    }
+}
+
 #[derive(Debug)]
 pub struct TcpListener {
-    raw: *mut lwip_sys::tcp_pcb,
-    backlog: Box<LinkedList<TcpStream>>
+    raw:   *mut lwip_sys::tcp_pcb,
+    state: Box<TcpListenerState>
 }
 
 impl TcpListener {
@@ -269,8 +307,8 @@ impl TcpListener {
                          err: lwip_sys::err) -> lwip_sys::err {
             if err != lwip_sys::ERR_OK { return err }
             unsafe {
-                let backlog = arg as *mut LinkedList<TcpStream>;
-                (*backlog).push_back(TcpStream::from_raw(newpcb));
+                let state = arg as *mut TcpListenerState;
+                (*state).backlog.push_back(TcpStream::from_raw(newpcb));
             }
             lwip_sys::ERR_OK
         }
@@ -278,10 +316,6 @@ impl TcpListener {
         unsafe {
             let raw = lwip_sys::tcp_new();
             if raw.is_null() { return Err(Error::OutOfMemory) }
-
-            let mut backlog = Box::new(LinkedList::new());
-            let arg = &mut *backlog as *mut LinkedList<TcpStream> as *mut _;
-            lwip_sys::tcp_arg(raw, arg);
             try!(result_from(lwip_sys::tcp_bind(raw, &mut addr.ip.into_raw(), addr.port),
                              || ()));
 
@@ -290,13 +324,23 @@ impl TcpListener {
                 lwip_sys::tcp_abort(raw);
                 return Err(Error::OutOfMemory)
             }
+
+            let mut state = Box::new(TcpListenerState {
+                backlog: LinkedList::new()
+            });
+            let arg = &mut *state as *mut TcpListenerState as *mut _;
+            lwip_sys::tcp_arg(raw, arg);
             lwip_sys::tcp_accept(raw2, accept);
-            Ok(TcpListener { raw: raw2, backlog: backlog })
+            Ok(TcpListener { raw: raw2, state: state })
         }
     }
 
+    pub fn state(&self) -> *const TcpListenerState {
+        &*self.state
+    }
+
     pub fn try_accept(&mut self) -> Option<TcpStream> {
-        self.backlog.pop_front()
+        self.state.backlog.pop_front()
     }
 
     pub fn close(self) {
@@ -320,61 +364,96 @@ pub enum Shutdown {
     Both,
 }
 
+#[derive(Debug)]
+pub struct TcpStreamState {
+    recv_buffer: LinkedList<Result<Pbuf<'static>>>,
+    send_avail:  usize
+}
+
+impl TcpStreamState {
+    pub fn readable(&self) -> bool {
+        !self.recv_buffer.is_empty()
+    }
+
+    pub fn writeable(&self) -> bool {
+        !(self.send_avail == 0)
+    }
+}
+
 #[derive(Debug)]
 pub struct TcpStream {
-    raw: *mut lwip_sys::tcp_pcb,
-    buffer: Box<LinkedList<Result<Pbuf<'static>>>>
+    raw:   *mut lwip_sys::tcp_pcb,
+    state: Box<TcpStreamState>
 }
 
 impl TcpStream {
     fn from_raw(raw: *mut lwip_sys::tcp_pcb) -> TcpStream {
-        extern fn recv(arg: *mut c_void, _tcb: *mut lwip_sys::tcp_pcb,
+        extern fn recv(arg: *mut c_void, _raw: *mut lwip_sys::tcp_pcb,
                        pbuf: *mut lwip_sys::pbuf, err: lwip_sys::err) -> lwip_sys::err {
             if err != lwip_sys::ERR_OK { return err }
             unsafe {
-                let buffer = arg as *mut LinkedList<Result<Pbuf<'static>>>;
+                let state = arg as *mut TcpStreamState;
                 if pbuf.is_null() {
-                    (*buffer).push_back(Err(Error::ConnectionClosed))
+                    (*state).recv_buffer.push_back(Err(Error::ConnectionClosed))
                 } else {
-                    (*buffer).push_back(Ok(Pbuf::from_raw(pbuf)))
+                    (*state).recv_buffer.push_back(Ok(Pbuf::from_raw(pbuf)))
                 }
             }
             lwip_sys::ERR_OK
         }
 
+        extern fn sent(arg: *mut c_void, raw: *mut lwip_sys::tcp_pcb,
+                       _len: u16) -> lwip_sys::err {
+            unsafe {
+                let state = arg as *mut TcpStreamState;
+                (*state).send_avail = lwip_sys::tcp_sndbuf_(raw) as usize;
+            }
+            lwip_sys::ERR_OK
+        }
+
         extern fn err(arg: *mut c_void, err: lwip_sys::err) {
             unsafe {
-                let buffer = arg as *mut LinkedList<Result<Pbuf<'static>>>;
-                (*buffer).push_back(result_from(err, || unreachable!()))
+                let state = arg as *mut TcpStreamState;
+                (*state).recv_buffer.push_back(result_from(err, || unreachable!()))
             }
         }
 
         unsafe {
-            let mut buffer = Box::new(LinkedList::new());
-            let arg = &mut *buffer as *mut LinkedList<Result<Pbuf<'static>>> as *mut _;
+            let mut state = Box::new(TcpStreamState {
+                recv_buffer: LinkedList::new(),
+                send_avail:  lwip_sys::tcp_sndbuf_(raw) as usize
+            });
+            let arg = &mut *state as *mut TcpStreamState as *mut _;
             lwip_sys::tcp_arg(raw, arg);
             lwip_sys::tcp_recv(raw, recv);
+            lwip_sys::tcp_sent(raw, sent);
             lwip_sys::tcp_err(raw, err);
-            TcpStream { raw: raw, buffer: buffer }
+            TcpStream { raw: raw, state: state }
         }
     }
 
+    pub fn state(&self) -> *const TcpStreamState {
+        &*self.state
+    }
+
     pub fn write(&mut self, data: &[u8]) -> Result<usize> {
         let sndbuf = unsafe { lwip_sys::tcp_sndbuf_(self.raw) } as usize;
         let len = if data.len() < sndbuf { data.len() } else { sndbuf };
-        result_from(unsafe {
+        let result = result_from(unsafe {
             lwip_sys::tcp_write(self.raw, data as *const [u8] as *const _, len as u16,
                                 lwip_sys::TCP_WRITE_FLAG_COPY)
-        }, || len)
+        }, || len);
+        self.state.send_avail = unsafe { lwip_sys::tcp_sndbuf_(self.raw) } as usize;
+        result
     }
 
     pub fn try_read(&mut self) -> Result<Option<Pbuf<'static>>> {
-        match self.buffer.front() {
+        match self.state.recv_buffer.front() {
             None => return Ok(None),
             Some(&Err(err)) => return Err(err),
             Some(_) => ()
         }
-        match self.buffer.pop_front() {
+        match self.state.recv_buffer.pop_front() {
             Some(Ok(pbuf)) => return Ok(Some(pbuf)),
             _ => unreachable!()
         }

artiq/runtime.rs/src/io.rs

@@ -1,4 +1,5 @@
 extern crate fringe;
+extern crate lwip;
 
 use std::vec::Vec;
 use std::time::{Instant, Duration};
@@ -102,15 +103,38 @@ impl Scheduler {
 }
 
 #[derive(Debug)]
-enum WaitEvent {}
+enum WaitEvent {
+    UdpReadable(*const lwip::UdpSocketState),
+    TcpAcceptable(*const lwip::TcpListenerState),
+    TcpWriteable(*const lwip::TcpStreamState),
+    TcpReadable(*const lwip::TcpStreamState),
+}
 
 impl WaitEvent {
     fn completed(&self) -> bool {
-        match *self {}
+        match *self {
+            WaitEvent::UdpReadable(state) =>
+                unsafe { (*state).readable() },
+            WaitEvent::TcpAcceptable(state) =>
+                unsafe { (*state).acceptable() },
+            WaitEvent::TcpWriteable(state) =>
+                unsafe { (*state).writeable() },
+            WaitEvent::TcpReadable(state) =>
+                unsafe { (*state).readable() },
+        }
     }
 }
 
-pub type Result<T> = ::std::result::Result<T, ()>;
+unsafe impl Send for WaitEvent {}
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum Error {
+    Lwip(lwip::Error),
+    TimedOut,
+    Interrupted
+}
+
+pub type Result<T> = ::std::result::Result<T, Error>;
 
 #[derive(Debug)]
 pub struct Waiter<'a>(&'a mut Yielder<WaitResult, WaitRequest, OwnedStack>);
@@ -124,8 +148,44 @@ impl<'a> Waiter<'a> {
 
         match self.0.suspend(request) {
             WaitResult::TimedOut => Ok(()),
-            WaitResult::Interrupted => Err(()),
+            WaitResult::Interrupted => Err(Error::Interrupted),
             _ => unreachable!()
         }
     }
+
+    fn suspend(&mut self, request: WaitRequest) -> Result<()> {
+        match self.0.suspend(request) {
+            WaitResult::Completed => Ok(()),
+            WaitResult::TimedOut => Err(Error::TimedOut),
+            WaitResult::Interrupted => Err(Error::Interrupted)
+        }
+    }
+
+    pub fn udp_readable(&mut self, socket: &lwip::UdpSocket) -> Result<()> {
+        self.suspend(WaitRequest {
+            timeout: None,
+            event:   Some(WaitEvent::UdpReadable(socket.state()))
+        })
+    }
+
+    pub fn tcp_acceptable(&mut self, socket: &lwip::TcpListener) -> Result<()> {
+        self.suspend(WaitRequest {
+            timeout: None,
+            event:   Some(WaitEvent::TcpAcceptable(socket.state()))
+        })
+    }
+
+    pub fn tcp_writeable(&mut self, socket: &lwip::TcpStream) -> Result<()> {
+        self.suspend(WaitRequest {
+            timeout: None,
+            event:   Some(WaitEvent::TcpWriteable(socket.state()))
+        })
+    }
+
+    pub fn tcp_readable(&mut self, socket: &lwip::TcpStream) -> Result<()> {
+        self.suspend(WaitRequest {
+            timeout: None,
+            event:   Some(WaitEvent::TcpReadable(socket.state()))
+        })
+    }
 }

artiq/runtime.rs/src/lib.rs

@@ -14,17 +14,21 @@ extern {
     fn lwip_service();
 }
 
-fn test1(mut waiter: io::Waiter) {
+fn timer(mut waiter: io::Waiter) {
     loop {
-        println!("A");
-        waiter.sleep(std::time::Duration::from_millis(1000));
+        println!("tick");
+        waiter.sleep(std::time::Duration::from_millis(1000)).unwrap();
     }
 }
 
-fn test2(mut waiter: io::Waiter) {
+fn echo(mut waiter: io::Waiter) {
+    let mut socket = lwip::UdpSocket::new().unwrap();
+    socket.bind(lwip::SocketAddr::new(lwip::IP_ANY, 1234)).unwrap();
     loop {
-        println!("B");
-        waiter.sleep(std::time::Duration::from_millis(500));
+        waiter.udp_readable(&socket).unwrap();
+        let (addr, pbuf) = socket.try_recv().unwrap();
+        println!("{:?}", core::str::from_utf8(pbuf.as_slice()));
+        socket.send_to(addr, pbuf).unwrap();
     }
 }
 
@@ -33,19 +37,11 @@ pub unsafe extern fn rust_main() {
     println!("Accepting network sessions in Rust.");
     network_init();
 
-    let addr = lwip::SocketAddr::new(lwip::IP4_ANY, 1234);
-    let mut listener = lwip::TcpListener::bind(addr).unwrap();
-    let mut stream = None;
+    let mut scheduler = io::Scheduler::new();
+    scheduler.spawn(4096, timer);
+    scheduler.spawn(4096, echo);
     loop {
         lwip_service();
-        if let Some(new_stream) = listener.try_accept() {
-            stream = Some(new_stream)
-        }
-        if let Some(ref mut stream) = stream {
-            if let Some(pbuf) = stream.try_read().expect("read") {
-                println!("{:?}", pbuf.as_slice());
-                stream.write(pbuf.as_slice()).expect("write");
-            }
-        }
+        scheduler.run()
     }
 }