Implement TCP retransmission.

README.md

@@ -52,6 +52,8 @@ The TCP protocol is supported over IPv4.
 
   * TCP header checksum is supported.
   * Multiple packets will be transmitted without waiting for an acknowledgement.
+  * Lost packets will be retransmitted with exponential backoff, starting at
+    a fixed delay of 100 ms.
   * TCP urgent pointer is **not** supported; any urgent octets will be received alongside
     data octets.
   * Reassembly of out-of-order segments is **not** supported.

examples/server.rs

@@ -43,11 +43,11 @@ fn main() {
         .format(move |record: &LogRecord| {
             let elapsed = Instant::now().duration_since(startup_time);
             if record.target().starts_with("smoltcp::") {
-                format!("\x1b[0m[{:6}.{:03}ms] ({}): {}\x1b[0m",
+                format!("\x1b[0m[{:6}.{:03}s] ({}): {}\x1b[0m",
                         elapsed.as_secs(), elapsed.subsec_nanos() / 1000000,
                         record.target().replace("smoltcp::", ""), record.args())
             } else {
-                format!("\x1b[32m[{:6}.{:03}ms] ({}): {}\x1b[0m",
+                format!("\x1b[32m[{:6}.{:03}s] ({}): {}\x1b[0m",
                         elapsed.as_secs(), elapsed.subsec_nanos() / 1000000,
                         record.target(), record.args())
             }
@@ -169,7 +169,10 @@ fn main() {
             }
         }
 
-        match iface.poll() {
+        let timestamp = Instant::now().duration_since(startup_time);
+        let timestamp_ms = (timestamp.as_secs() * 1000) +
+                           (timestamp.subsec_nanos() / 1000000) as u64;
+        match iface.poll(timestamp_ms) {
             Ok(()) => (),
             Err(e) => debug!("poll error: {}", e)
         }

src/iface/ethernet.rs

@@ -112,7 +112,9 @@ impl<'a, 'b: 'a,
     }
 
     /// Receive and process a packet, if available, and then transmit a packet, if necessary.
-    pub fn poll(&mut self) -> Result<(), Error> {
+    ///
+    /// The timestamp is a monotonically increasing number of milliseconds.
+    pub fn poll(&mut self, timestamp: u64) -> Result<(), Error> {
         enum Response<'a> {
             Nop,
             Arp(ArpRepr),
@@ -122,7 +124,7 @@ impl<'a, 'b: 'a,
 
         // First, transmit any outgoing packets.
         loop {
-            if try!(self.emit()) { break }
+            if try!(self.emit(timestamp)) { break }
         }
 
         // Now, receive any incoming packets.
@@ -214,7 +216,7 @@ impl<'a, 'b: 'a,
                         let mut handled = false;
                         for socket in self.sockets.borrow_mut() {
                             let ip_repr = IpRepr::Ipv4(ipv4_repr);
-                            match socket.process(&ip_repr, ipv4_packet.payload()) {
+                            match socket.process(timestamp, &ip_repr, ipv4_packet.payload()) {
                                 Ok(()) => {
                                     // The packet was valid and handled by socket.
                                     handled = true;
@@ -355,7 +357,7 @@ impl<'a, 'b: 'a,
         }
     }
 
-    fn emit(&mut self) -> Result<bool, Error> {
+    fn emit(&mut self, timestamp: u64) -> Result<bool, Error> {
         // Borrow checker is being overly careful around closures, so we have
         // to hack around that.
         let src_hardware_addr = self.hardware_addr;
@@ -365,7 +367,7 @@ impl<'a, 'b: 'a,
 
         let mut nothing_to_transmit = true;
         for socket in self.sockets.borrow_mut() {
-            let result = socket.dispatch(&mut |repr, payload| {
+            let result = socket.dispatch(timestamp, &mut |repr, payload| {
                 let repr = try!(repr.lower(src_protocol_addrs));
 
                 let dst_hardware_addr =

src/socket/mod.rs

@@ -52,12 +52,13 @@ impl<'a, 'b> Socket<'a, 'b> {
     /// is returned.
     ///
     /// This function is used internally by the networking stack.
-    pub fn process(&mut self, ip_repr: &IpRepr, payload: &[u8]) -> Result<(), Error> {
+    pub fn process(&mut self, timestamp: u64, ip_repr: &IpRepr,
+                   payload: &[u8]) -> Result<(), Error> {
         match self {
             &mut Socket::Udp(ref mut socket) =>
-                socket.process(ip_repr, payload),
+                socket.process(timestamp, ip_repr, payload),
             &mut Socket::Tcp(ref mut socket) =>
-                socket.process(ip_repr, payload),
+                socket.process(timestamp, ip_repr, payload),
             &mut Socket::__Nonexhaustive => unreachable!()
         }
     }
@@ -69,13 +70,13 @@ impl<'a, 'b> Socket<'a, 'b> {
     /// is returned.
     ///
     /// This function is used internally by the networking stack.
-    pub fn dispatch<F, R>(&mut self, emit: &mut F) -> Result<R, Error>
+    pub fn dispatch<F, R>(&mut self, timestamp: u64, emit: &mut F) -> Result<R, Error>
             where F: FnMut(&IpRepr, &IpPayload) -> Result<R, Error> {
         match self {
             &mut Socket::Udp(ref mut socket) =>
-                socket.dispatch(emit),
+                socket.dispatch(timestamp, emit),
             &mut Socket::Tcp(ref mut socket) =>
-                socket.dispatch(emit),
+                socket.dispatch(timestamp, emit),
             &mut Socket::__Nonexhaustive => unreachable!()
         }
     }

src/socket/tcp.rs

@@ -146,22 +146,53 @@ impl fmt::Display for State {
 
 #[derive(Debug)]
 struct Retransmit {
-    sent: bool // FIXME
+    resend_at: u64,
+    delay:     u64
 }
 
 impl Retransmit {
     fn new() -> Retransmit {
-        Retransmit { sent: false }
+        Retransmit { resend_at: 0, delay: 0 }
     }
 
     fn reset(&mut self) {
-        self.sent = false
+        self.resend_at = 0;
+        self.delay     = 0;
     }
 
-    fn check(&mut self) -> bool {
-        let result = !self.sent;
-        self.sent = true;
-        result
+    fn may_send_old(&mut self, timestamp: u64) -> bool {
+        if self.delay == 0 {
+            // We haven't transmitted anything yet.
+            false
+        } else if timestamp < self.resend_at {
+            // We may not retransmit yet.
+            false
+        } else {
+            // We may retransmit!
+            true
+        }
+    }
+
+    fn may_send_new(&mut self, timestamp: u64) -> bool {
+        if self.delay == 0 {
+            // We've something new to transmit, do it unconditionally.
+            self.delay      = 100; // ms
+            self.resend_at  = timestamp + self.delay;
+            true
+        } else {
+            false
+        }
+    }
+
+    fn commit(&mut self, timestamp: u64) {
+        if self.delay == 0 {
+            self.delay      = 100; // ms
+            self.resend_at  = timestamp + self.delay;
+        } else if timestamp >= self.resend_at {
+            net_trace!("retransmitting after a {}ms delay", self.delay);
+            self.resend_at  = timestamp + self.delay;
+            self.delay     *= 2;
+        }
     }
 }
 
@@ -373,6 +404,7 @@ impl<'a> TcpSocket<'a> {
             net_trace!("tcp:{}:{}: tx buffer: enqueueing {} octets (now {})",
                        self.local_endpoint, self.remote_endpoint,
                        buffer.len(), old_length + buffer.len());
+            self.retransmit.reset();
         }
         Ok(buffer)
     }
@@ -445,7 +477,8 @@ impl<'a> TcpSocket<'a> {
     }
 
     /// See [Socket::process](enum.Socket.html#method.process).
-    pub fn process(&mut self, ip_repr: &IpRepr, payload: &[u8]) -> Result<(), Error> {
+    pub fn process(&mut self, _timestamp: u64, ip_repr: &IpRepr,
+                   payload: &[u8]) -> Result<(), Error> {
         if ip_repr.protocol() != IpProtocol::Tcp { return Err(Error::Rejected) }
 
         let packet = try!(TcpPacket::new(payload));
@@ -545,6 +578,7 @@ impl<'a> TcpSocket<'a> {
                     // If we've seen this sequence number already but the remote end is not aware
                     // of that, make sure we send the acknowledgement again.
                     self.remote_last_ack = next_remote_seq - 1;
+                    self.retransmit.reset();
                     return Ok(())
                 }
             }
@@ -679,7 +713,7 @@ impl<'a> TcpSocket<'a> {
     }
 
     /// See [Socket::dispatch](enum.Socket.html#method.dispatch).
-    pub fn dispatch<F, R>(&mut self, emit: &mut F) -> Result<R, Error>
+    pub fn dispatch<F, R>(&mut self, timestamp: u64, emit: &mut F) -> Result<R, Error>
             where F: FnMut(&IpRepr, &IpPayload) -> Result<R, Error> {
         if self.remote_endpoint.is_unspecified() { return Err(Error::Exhausted) }
 
@@ -698,6 +732,17 @@ impl<'a> TcpSocket<'a> {
             payload:    &[]
         };
 
+        if self.retransmit.may_send_old(timestamp) {
+            // The retransmit timer has expired, so assume all in-flight packets that
+            // have not been acknowledged are lost.
+            self.remote_last_seq = self.local_seq_no;
+        } else if self.retransmit.may_send_new(timestamp) {
+            // The retransmit timer has reset, and we can send something new.
+        } else {
+            // We don't have anything to send at this time.
+            return Err(Error::Exhausted)
+        }
+
         let mut should_send = false;
         match self.state {
             // We never transmit anything in the CLOSED, LISTEN, or FIN-WAIT-2 states.
@@ -707,8 +752,6 @@ impl<'a> TcpSocket<'a> {
 
             // We transmit a SYN|ACK in the SYN-RECEIVED state.
             State::SynReceived => {
-                if !self.retransmit.check() { return Err(Error::Exhausted) }
-
                 repr.control = TcpControl::Syn;
                 net_trace!("tcp:{}:{}: sending SYN|ACK",
                            self.local_endpoint, self.remote_endpoint);
@@ -717,8 +760,6 @@ impl<'a> TcpSocket<'a> {
 
             // We transmit a SYN in the SYN-SENT state.
             State::SynSent => {
-                if !self.retransmit.check() { return Err(Error::Exhausted) }
-
                 repr.control = TcpControl::Syn;
                 repr.ack_number = None;
                 net_trace!("tcp:{}:{}: sending SYN",
@@ -728,55 +769,53 @@ impl<'a> TcpSocket<'a> {
 
             // We transmit data in the ESTABLISHED state,
             // ACK in CLOSE-WAIT, CLOSING, and TIME-WAIT states,
-            // FIN in FIN-WAIT-1 and LAST-ACK states.
+            // FIN in FIN-WAIT-1 and LAST-ACK states,
+            // but only if the receiver has a nonzero window.
             State::Established |
             State::CloseWait   | State::Closing | State::TimeWait |
-            State::FinWait1    | State::LastAck => {
-                // See if we should send data to the remote end because:
-                let mut may_send = false;
-                //   1. the retransmit timer has expired or was reset, or...
-                if self.retransmit.check() { may_send = true }
-                //   2. we've got new data in the transmit buffer.
-                let remote_next_seq = self.local_seq_no + self.tx_buffer.len();
-                if self.remote_last_seq != remote_next_seq { may_send = true }
-
-                if self.tx_buffer.len() > 0 && self.remote_win_len > 0 && may_send {
-                    // We can send something, so let's do that.
-                    let mut size = self.tx_buffer.len();
-                    // Clamp to remote window length.
-                    if size > self.remote_win_len { size = self.remote_win_len }
-                    // Clamp to MSS. Currently we only support the default MSS value.
-                    if size > 536 { size = 536 }
-                    // Extract data from the buffer. This may return less than what we want,
-                    // in case it's not possible to extract a contiguous slice.
-                    let offset = self.remote_last_seq - self.local_seq_no;
-                    let data = self.tx_buffer.peek(offset, size);
-                    assert!(data.len() > 0);
-                    // Send the extracted data.
-                    net_trace!("tcp:{}:{}: tx buffer: peeking at {} octets (from {})",
-                               self.local_endpoint, self.remote_endpoint, data.len(), offset);
-                    repr.seq_number += offset;
-                    repr.payload = data;
-                    // Speculatively shrink the remote window. This will get updated the next
-                    // time we receive a packet.
-                    self.remote_win_len  -= data.len();
-                    // Advance the in-flight sequence number.
-                    self.remote_last_seq += data.len();
-                    should_send = true;
-                }
-
+            State::FinWait1    | State::LastAck
+                    if self.remote_win_len > 0 => {
+                // We can send something, so let's try doing that.
+                let mut size = self.tx_buffer.len();
+                // Clamp to remote window length.
+                if size > self.remote_win_len { size = self.remote_win_len }
+                // Clamp to MSS. Currently we only support the default MSS value.
+                if size > 536 { size = 536 }
+                // Extract data from the buffer. This may return less than what we want,
+                // in case it's not possible to extract a contiguous slice.
+                let offset = self.remote_last_seq - self.local_seq_no;
+                let data = self.tx_buffer.peek(offset, size);
                 match self.state {
-                    State::FinWait1 | State::LastAck if may_send => {
+                    _ if data.len() > 0 => {
+                        // Send the extracted data.
+                        net_trace!("tcp:{}:{}: tx buffer: peeking at {} octets (from {})",
+                                   self.local_endpoint, self.remote_endpoint,
+                                   data.len(), offset);
+                        repr.seq_number += offset;
+                        repr.payload = data;
+                        // Speculatively shrink the remote window. This will get updated
+                        // the next time we receive a packet.
+                        self.remote_win_len  -= data.len();
+                        // Advance the in-flight sequence number.
+                        self.remote_last_seq += data.len();
+                        should_send = true;
+                    }
+                    State::FinWait1 | State::LastAck => {
                         // We should notify the other side that we've closed the transmit half
                         // of the connection.
                         net_trace!("tcp:{}:{}: sending FIN|ACK",
                                    self.local_endpoint, self.remote_endpoint);
                         repr.control = TcpControl::Fin;
                         should_send = true;
-                    },
+                    }
                     _ => ()
                 }
             }
+
+            // We don't transmit anything (except ACKs) if the receiver has a zero window.
+            State::Established |
+            State::CloseWait   | State::Closing | State::TimeWait |
+            State::FinWait1    | State::LastAck => ()
         }
 
         let ack_number = self.remote_seq_no + self.rx_buffer.len();
@@ -788,6 +827,8 @@ impl<'a> TcpSocket<'a> {
         }
 
         if should_send {
+            self.retransmit.commit(timestamp);
+
             repr.ack_number = Some(ack_number);
             self.remote_last_ack = ack_number;
 
@@ -842,6 +883,26 @@ mod test {
         assert_eq!(buffer.peek(3, 8), &b"bar"[..]);
     }
 
+    #[test]
+    fn test_retransmit_may_send() {
+        fn may_send(r: &mut Retransmit, t: u64) -> (bool, bool) {
+            (r.may_send_old(t), r.may_send_new(t))
+        }
+
+        let mut r = Retransmit::new();
+        assert_eq!(may_send(&mut r, 1000), (false, true));
+        r.commit(1000);
+        assert_eq!(may_send(&mut r, 1000), (false, false));
+        assert_eq!(may_send(&mut r, 1050), (false, false));
+        assert_eq!(may_send(&mut r, 1101), (true,  false));
+        r.commit(1101);
+        assert_eq!(may_send(&mut r, 1150), (false, false));
+        assert_eq!(may_send(&mut r, 1200), (false, false));
+        assert_eq!(may_send(&mut r, 1301), (true,  false));
+        r.reset();
+        assert_eq!(may_send(&mut r, 1350), (false, true));
+    }
+
     const LOCAL_IP:     IpAddress    = IpAddress::Ipv4(Ipv4Address([10, 0, 0, 1]));
     const REMOTE_IP:    IpAddress    = IpAddress::Ipv4(Ipv4Address([10, 0, 0, 2]));
     const LOCAL_PORT:   u16          = 80;
@@ -864,7 +925,7 @@ mod test {
         window_len: 64, payload: &[]
     };
 
-    fn send(socket: &mut TcpSocket, repr: &TcpRepr) -> Result<(), Error> {
+    fn send(socket: &mut TcpSocket, timestamp: u64, repr: &TcpRepr) -> Result<(), Error> {
         trace!("send: {}", repr);
         let mut buffer = vec![0; repr.buffer_len()];
         let mut packet = TcpPacket::new(&mut buffer).unwrap();
@@ -874,13 +935,13 @@ mod test {
             dst_addr: LOCAL_IP,
             protocol: IpProtocol::Tcp
         };
-        socket.process(&ip_repr, &packet.into_inner()[..])
+        socket.process(timestamp, &ip_repr, &packet.into_inner()[..])
     }
 
-    fn recv<F>(socket: &mut TcpSocket, mut f: F)
+    fn recv<F>(socket: &mut TcpSocket, timestamp: u64, mut f: F)
             where F: FnMut(Result<TcpRepr, Error>) {
         let mut buffer = vec![];
-        let result = socket.dispatch(&mut |ip_repr, payload| {
+        let result = socket.dispatch(timestamp, &mut |ip_repr, payload| {
             assert_eq!(ip_repr.protocol(), IpProtocol::Tcp);
             assert_eq!(ip_repr.src_addr(), LOCAL_IP);
             assert_eq!(ip_repr.dst_addr(), REMOTE_IP);
@@ -900,11 +961,14 @@ mod test {
     }
 
     macro_rules! send {
-        ($socket:ident, [$( $repr:expr )*]) => ({
-            $( send!($socket, $repr, Ok(())); )*
-        });
+        ($socket:ident, $repr:expr) =>
+            (send!($socket, time 0, $repr));
         ($socket:ident, $repr:expr, $result:expr) =>
-            (assert_eq!(send(&mut $socket, &$repr), $result))
+            (send!($socket, time 0, $repr, $result));
+        ($socket:ident, time $time:expr, $repr:expr) =>
+            (send!($socket, time 0, $repr, Ok(())));
+        ($socket:ident, time $time:expr, $repr:expr, $result:expr) =>
+            (assert_eq!(send(&mut $socket, $time, &$repr), $result));
     }
 
     macro_rules! recv {
@@ -913,7 +977,9 @@ mod test {
             recv!($socket, Err(Error::Exhausted))
         });
         ($socket:ident, $result:expr) =>
-            (recv(&mut $socket, |repr| assert_eq!(repr, $result)))
+            (recv!($socket, time 0, $result));
+        ($socket:ident, time $time:expr, $result:expr) =>
+            (recv(&mut $socket, $time, |repr| assert_eq!(repr, $result)));
     }
 
     fn init_logger() {
@@ -997,12 +1063,12 @@ mod test {
     #[test]
     fn test_listen_rst() {
         let mut s = socket_listen();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Rst,
             seq_number: REMOTE_SEQ,
             ack_number: None,
             ..SEND_TEMPL
-        }]);
+        });
     }
 
     #[test]
@@ -1028,12 +1094,12 @@ mod test {
     #[test]
     fn test_syn_received_rst() {
         let mut s = socket_syn_received();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Rst,
             seq_number: REMOTE_SEQ,
             ack_number: Some(LOCAL_SEQ),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::Listen);
         assert_eq!(s.local_endpoint, IpEndpoint::new(IpAddress::Unspecified, LOCAL_END.port));
         assert_eq!(s.remote_endpoint, IpEndpoint::default());
@@ -1061,12 +1127,12 @@ mod test {
     #[test]
     fn test_syn_sent_rst() {
         let mut s = socket_syn_sent();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Rst,
             seq_number: REMOTE_SEQ,
             ack_number: Some(LOCAL_SEQ),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::Closed);
     }
 
@@ -1118,12 +1184,12 @@ mod test {
     #[test]
     fn test_established_recv() {
         let mut s = socket_established();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             payload: &b"abcdef"[..],
             ..SEND_TEMPL
-        }]);
+        });
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
             ack_number: Some(REMOTE_SEQ + 1 + 6),
@@ -1137,7 +1203,7 @@ mod test {
     fn test_established_send() {
         let mut s = socket_established();
         // First roundtrip after establishing.
-        s.tx_buffer.enqueue_slice(b"abcdef");
+        s.send_slice(b"abcdef").unwrap();
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
             ack_number: Some(REMOTE_SEQ + 1),
@@ -1145,39 +1211,39 @@ mod test {
             ..RECV_TEMPL
         }]);
         assert_eq!(s.tx_buffer.len(), 6);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 6),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.tx_buffer.len(), 0);
         // Second roundtrip.
-        s.tx_buffer.enqueue_slice(b"foobar");
+        s.send_slice(b"foobar").unwrap();
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1 + 6,
             ack_number: Some(REMOTE_SEQ + 1),
             payload: &b"foobar"[..],
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 6 + 6),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.tx_buffer.len(), 0);
     }
 
     #[test]
     fn test_established_send_no_ack_send() {
         let mut s = socket_established();
-        s.tx_buffer.enqueue_slice(b"abcdef");
+        s.send_slice(b"abcdef").unwrap();
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
             ack_number: Some(REMOTE_SEQ + 1),
             payload: &b"abcdef"[..],
             ..RECV_TEMPL
         }]);
-        s.tx_buffer.enqueue_slice(b"foobar");
+        s.send_slice(b"foobar").unwrap();
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1 + 6,
             ack_number: Some(REMOTE_SEQ + 1),
@@ -1191,7 +1257,7 @@ mod test {
         let mut s = socket_established();
         s.remote_win_len = 16;
         // First roundtrip after establishing.
-        s.tx_buffer.enqueue_slice(&[0; 32][..]);
+        s.send_slice(&[0; 32][..]).unwrap();
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
             ack_number: Some(REMOTE_SEQ + 1),
@@ -1244,12 +1310,12 @@ mod test {
     #[test]
     fn test_established_fin() {
         let mut s = socket_established();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Fin,
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::CloseWait);
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
@@ -1261,13 +1327,13 @@ mod test {
     #[test]
     fn test_established_send_fin() {
         let mut s = socket_established();
-        s.tx_buffer.enqueue_slice(b"abcdef");
-        send!(s, [TcpRepr {
+        s.send_slice(b"abcdef").unwrap();
+        send!(s, TcpRepr {
             control: TcpControl::Fin,
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::CloseWait);
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
@@ -1280,24 +1346,24 @@ mod test {
     #[test]
     fn test_established_rst() {
         let mut s = socket_established();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Rst,
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::Closed);
     }
 
     #[test]
     fn test_established_rst_no_ack() {
         let mut s = socket_established();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Rst,
             seq_number: REMOTE_SEQ + 1,
             ack_number: None,
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::Closed);
     }
 
@@ -1326,11 +1392,11 @@ mod test {
             ack_number: Some(REMOTE_SEQ + 1),
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::FinWait2);
     }
 
@@ -1343,12 +1409,12 @@ mod test {
             ack_number: Some(REMOTE_SEQ + 1),
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Fin,
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::Closing);
     }
 
@@ -1372,12 +1438,12 @@ mod test {
     #[test]
     fn test_fin_wait_2_fin() {
         let mut s = socket_fin_wait_2();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Fin,
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::TimeWait);
     }
 
@@ -1407,11 +1473,11 @@ mod test {
             ack_number: Some(REMOTE_SEQ + 1 + 1),
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1 + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::TimeWait);
     }
 
@@ -1472,18 +1538,18 @@ mod test {
     #[test]
     fn test_close_wait_ack() {
         let mut s = socket_close_wait();
-        s.tx_buffer.enqueue_slice(b"abcdef");
+        s.send_slice(b"abcdef").unwrap();
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
             ack_number: Some(REMOTE_SEQ + 1 + 1),
             payload: &b"abcdef"[..],
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1 + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 6),
             ..SEND_TEMPL
-        }]);
+        });
     }
 
     #[test]
@@ -1512,11 +1578,11 @@ mod test {
             ..RECV_TEMPL
         }]);
         assert_eq!(s.state, State::LastAck);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1 + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::Closed);
     }
 
@@ -1540,12 +1606,12 @@ mod test {
     #[test]
     fn test_three_way_handshake() {
         let mut s = socket_listen();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Syn,
             seq_number: REMOTE_SEQ,
             ack_number: None,
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state(), State::SynReceived);
         assert_eq!(s.local_endpoint(), LOCAL_END);
         assert_eq!(s.remote_endpoint(), REMOTE_END);
@@ -1555,11 +1621,11 @@ mod test {
             ack_number: Some(REMOTE_SEQ + 1),
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state(), State::Established);
         assert_eq!(s.local_seq_no, LOCAL_SEQ + 1);
         assert_eq!(s.remote_seq_no, REMOTE_SEQ + 1);
@@ -1568,12 +1634,12 @@ mod test {
     #[test]
     fn test_remote_close() {
         let mut s = socket_established();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Fin,
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::CloseWait);
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
@@ -1588,11 +1654,11 @@ mod test {
             ack_number: Some(REMOTE_SEQ + 1 + 1),
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1 + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::Closed);
     }
 
@@ -1607,18 +1673,18 @@ mod test {
             ack_number: Some(REMOTE_SEQ + 1),
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::FinWait2);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Fin,
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::TimeWait);
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1 + 1,
@@ -1638,12 +1704,12 @@ mod test {
             ack_number: Some(REMOTE_SEQ + 1),
             ..RECV_TEMPL
         }]);
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             control: TcpControl::Fin,
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::Closing);
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
@@ -1651,11 +1717,11 @@ mod test {
             ..RECV_TEMPL
         }]);
         // ... at this point
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1 + 1,
             ack_number: Some(LOCAL_SEQ + 1 + 1),
             ..SEND_TEMPL
-        }]);
+        });
         assert_eq!(s.state, State::TimeWait);
         recv!(s, []);
     }
@@ -1665,12 +1731,12 @@ mod test {
     // =========================================================================================//
     fn socket_recved() -> TcpSocket<'static> {
         let mut s = socket_established();
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             payload:    &b"abcdef"[..],
             ..SEND_TEMPL
-        }]);
+        });
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
             ack_number: Some(REMOTE_SEQ + 1 + 6),
@@ -1684,12 +1750,12 @@ mod test {
     fn test_duplicate_seq_ack() {
         let mut s = socket_recved();
         // remote retransmission
-        send!(s, [TcpRepr {
+        send!(s, TcpRepr {
             seq_number: REMOTE_SEQ + 1,
             ack_number: Some(LOCAL_SEQ + 1),
             payload:    &b"abcdef"[..],
             ..SEND_TEMPL
-        }]);
+        });
         recv!(s, [TcpRepr {
             seq_number: LOCAL_SEQ + 1,
             ack_number: Some(REMOTE_SEQ + 1 + 6),
@@ -1697,4 +1763,23 @@ mod test {
             ..RECV_TEMPL
         }]);
     }
+
+    #[test]
+    fn test_data_retransmit() {
+        let mut s = socket_established();
+        s.send_slice(b"abcdef").unwrap();
+        recv!(s, time 1000, Ok(TcpRepr {
+            seq_number: LOCAL_SEQ + 1,
+            ack_number: Some(REMOTE_SEQ + 1),
+            payload:    &b"abcdef"[..],
+            ..RECV_TEMPL
+        }));
+        recv!(s, time 1050, Err(Error::Exhausted));
+        recv!(s, time 1100, Ok(TcpRepr {
+            seq_number: LOCAL_SEQ + 1,
+            ack_number: Some(REMOTE_SEQ + 1),
+            payload:    &b"abcdef"[..],
+            ..RECV_TEMPL
+        }));
+    }
 }

src/socket/udp.rs

@@ -168,7 +168,8 @@ impl<'a, 'b> UdpSocket<'a, 'b> {
     }
 
     /// See [Socket::process](enum.Socket.html#method.process).
-    pub fn process(&mut self, ip_repr: &IpRepr, payload: &[u8]) -> Result<(), Error> {
+    pub fn process(&mut self, _timestamp: u64, ip_repr: &IpRepr,
+                   payload: &[u8]) -> Result<(), Error> {
         if ip_repr.protocol() != IpProtocol::Udp { return Err(Error::Rejected) }
 
         let packet = try!(UdpPacket::new(payload));
@@ -189,7 +190,7 @@ impl<'a, 'b> UdpSocket<'a, 'b> {
     }
 
     /// See [Socket::dispatch](enum.Socket.html#method.dispatch).
-    pub fn dispatch<F, R>(&mut self, emit: &mut F) -> Result<R, Error>
+    pub fn dispatch<F, R>(&mut self, _timestamp: u64, emit: &mut F) -> Result<R, Error>
             where F: FnMut(&IpRepr, &IpPayload) -> Result<R, Error> {
         let packet_buf = try!(self.tx_buffer.dequeue());
         net_trace!("udp:{}:{}: sending {} octets",