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tcp: don't send data outside the remote window

v0.7.x
Dario Nieuwenhuis 2020-12-18 16:06:23 +01:00 committed by whitequark
parent 42dc04852b
commit f89d240c29
1 changed files with 14 additions and 29 deletions
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43
src/socket/tcp.rs
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@ -230,8 +230,8 @@ pub struct TcpSocket<'a> {
/// The sending window scaling factor advertised to remotes which support RFC 1323.
/// It is zero if the window <= 64KiB and/or the remote does not support it.
remote_win_shift: u8,
/// The speculative remote window size.
/// I.e. the actual remote window size minus the count of in-flight octets.
/// The remote window size, relative to local_seq_no
/// I.e. we're allowed to send octets until local_seq_no+remote_win_len
remote_win_len: usize,
/// The receive window scaling factor for remotes which support RFC 1323, None if unsupported.
remote_win_scale: Option<u8>,
@ -1410,11 +1410,11 @@ impl<'a> TcpSocket<'a> {
_ => control = TcpControl::None
}
if self.remote_win_len > 0 {
self.remote_last_seq < self.local_seq_no + self.tx_buffer.len() + control.len()
} else {
false
}
self.remote_last_seq <
self.local_seq_no + core::cmp::min(
self.remote_win_len,
self.tx_buffer.len()
) + control.len()
}
fn ack_to_transmit(&self) -> bool {
@ -1558,7 +1558,8 @@ impl<'a> TcpSocket<'a> {
// Extract as much data as the remote side can receive in this packet
// from the transmit buffer.
let offset = self.remote_last_seq - self.local_seq_no;
let size = cmp::min(cmp::min(self.remote_win_len, self.remote_mss),
let win_limit = self.local_seq_no + self.remote_win_len - self.remote_last_seq;
let size = cmp::min(cmp::min(win_limit, self.remote_mss),
caps.max_transmission_unit - ip_repr.buffer_len() - repr.mss_header_len());
repr.payload = self.tx_buffer.get_allocated(offset, size);
// If we've sent everything we had in the buffer, follow it with the PSH or FIN
@ -2755,11 +2756,6 @@ mod test {
ack_number: Some(REMOTE_SEQ + 1),
payload: &data[0..16],
..RECV_TEMPL
}, TcpRepr {
seq_number: LOCAL_SEQ + 1 + 16,
ack_number: Some(REMOTE_SEQ + 1),
payload: &data[16..32],
..RECV_TEMPL
}]);
}
@ -3525,7 +3521,7 @@ mod test {
#[test]
fn test_data_retransmit_bursts() {
let mut s = socket_established();
s.remote_win_len = 6;
s.remote_mss = 6;
s.send_slice(b"abcdef012345").unwrap();
recv!(s, time 0, Ok(TcpRepr {
@ -3535,7 +3531,6 @@ mod test {
payload: &b"abcdef"[..],
..RECV_TEMPL
}), exact);
s.remote_win_len = 6;
recv!(s, time 0, Ok(TcpRepr {
control: TcpControl::Psh,
seq_number: LOCAL_SEQ + 1 + 6,
@ -3543,7 +3538,6 @@ mod test {
payload: &b"012345"[..],
..RECV_TEMPL
}), exact);
s.remote_win_len = 6;
recv!(s, time 0, Err(Error::Exhausted));
recv!(s, time 50, Err(Error::Exhausted));
@ -3555,7 +3549,6 @@ mod test {
payload: &b"abcdef"[..],
..RECV_TEMPL
}), exact);
s.remote_win_len = 6;
recv!(s, time 150, Ok(TcpRepr {
control: TcpControl::Psh,
seq_number: LOCAL_SEQ + 1 + 6,
@ -3563,7 +3556,6 @@ mod test {
payload: &b"012345"[..],
..RECV_TEMPL
}), exact);
s.remote_win_len = 6;
recv!(s, time 200, Err(Error::Exhausted));
}
@ -3791,12 +3783,12 @@ mod test {
#[test]
fn test_fast_retransmit_after_triple_duplicate_ack() {
let mut s = socket_established();
s.remote_mss = 6;
// Normal ACK of previously recived segment
send!(s, time 0, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1),
window_len: 6,
..SEND_TEMPL
});
@ -3833,14 +3825,12 @@ mod test {
send!(s, time 1050, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1),
window_len: 6,
..SEND_TEMPL
});
// Second duplicate ACK
send!(s, time 1055, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1),
window_len: 6,
..SEND_TEMPL
});
// Third duplicate ACK
@ -3848,7 +3838,6 @@ mod test {
send!(s, time 1060, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1),
window_len: 6,
..SEND_TEMPL
});
@ -3951,12 +3940,12 @@ mod test {
#[test]
fn test_fast_retransmit_duplicate_detection() {
let mut s = socket_established();
s.remote_mss = 6;
// Normal ACK of previously recived segment
send!(s, time 0, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1),
window_len: 6,
..SEND_TEMPL
});
@ -3964,7 +3953,6 @@ mod test {
send!(s, time 0, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1),
window_len: 6,
..SEND_TEMPL
});
@ -3972,7 +3960,7 @@ mod test {
"duplicate ACK counter is set but wound not transmit data");
// Send a long string of text divided into several packets
// because of previously recieved "window_len"
// because of small remote_mss
s.send_slice(b"xxxxxxyyyyyywwwwwwzzzzzz").unwrap();
// This packet is reordered in network
@ -4005,21 +3993,18 @@ mod test {
send!(s, time 1050, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1),
window_len: 6,
..SEND_TEMPL
});
// Second duplicate ACK
send!(s, time 1055, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1),
window_len: 6,
..SEND_TEMPL
});
// Reordered packet arrives which should reset duplicate ACK count
send!(s, time 1060, TcpRepr {
seq_number: REMOTE_SEQ + 1,
ack_number: Some(LOCAL_SEQ + 1 + (6 * 3)),
window_len: 6,
..SEND_TEMPL
});
@ -4174,7 +4159,7 @@ mod test {
#[test]
fn test_psh_transmit() {
let mut s = socket_established();
s.remote_win_len = 6;
s.remote_mss = 6;
s.send_slice(b"abcdef").unwrap();
s.send_slice(b"123456").unwrap();
recv!(s, time 0, Ok(TcpRepr {