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Implement the TCP TIME-WAIT state.

This commit is contained in:
whitequark 2016-12-28 05:33:12 +00:00
parent 94963faf12
commit 287affb447
4 changed files with 150 additions and 34 deletions
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9
README.md
View File

@ -52,11 +52,12 @@ The TCP protocol is supported over IPv4.
* TCP header checksum is supported.
* Multiple packets will be transmitted without waiting for an acknowledgement.
* TCP urgent pointer is **not** supported; any urgent octets will be received alongside data.
* TCP urgent pointer is **not** supported; any urgent octets will be received alongside
data octets.
* Reassembly of out-of-order segments is **not** supported.
* TCP options are **not** supported, in particular:
* Maximum segment size is hardcoded at the default value, 536.
* Window scaling is **not** supported.
* Window scaling is **not** supported, and the maximum buffer size is 65536.
* Keepalive is **not** supported.
Installation
@ -143,7 +144,9 @@ It responds to:
* pings (`ping 192.168.69.1`);
* UDP packets on port 6969 (`socat stdio udp4-connect:192.168.69.1:6969 <<<"abcdefg"`),
where it will respond "yo dawg" to any incoming packet;
* TCP packets on port 6969 (`socat stdio tcp4-connect:192.168.69.1:6969 <<<"abcdefg"`),
* TCP packets on port 6969 (`socat stdio tcp4-connect:192.168.69.1:6969`),
where it will respond "yo dawg" to any incoming connection and immediately close it;
* TCP packets on port 6970 (`socat stdio tcp4-connect:192.168.69.1:6970 <<<"abcdefg"`),
where it will respond with reversed chunks of the input indefinitely.
The buffers are only 64 bytes long, for convenience of testing resource exhaustion conditions.

51
examples/server.rs
View File

@ -53,23 +53,28 @@ fn main() {
let udp_tx_buffer = UdpSocketBuffer::new(vec![UdpPacketBuffer::new(vec![0; 128])]);
let udp_socket = UdpSocket::new(endpoint, udp_rx_buffer, udp_tx_buffer);
let tcp_rx_buffer = TcpSocketBuffer::new(vec![0; 64]);
let tcp_tx_buffer = TcpSocketBuffer::new(vec![0; 128]);
let tcp_socket = TcpSocket::new(tcp_rx_buffer, tcp_tx_buffer);
let tcp1_rx_buffer = TcpSocketBuffer::new(vec![0; 64]);
let tcp1_tx_buffer = TcpSocketBuffer::new(vec![0; 128]);
let tcp1_socket = TcpSocket::new(tcp1_rx_buffer, tcp1_tx_buffer);
let tcp2_rx_buffer = TcpSocketBuffer::new(vec![0; 64]);
let tcp2_tx_buffer = TcpSocketBuffer::new(vec![0; 128]);
let tcp2_socket = TcpSocket::new(tcp2_rx_buffer, tcp2_tx_buffer);
let hardware_addr = EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x01]);
let protocol_addrs = [IpAddress::v4(192, 168, 69, 1)];
let sockets = vec![udp_socket, tcp_socket];
let sockets = vec![udp_socket, tcp1_socket, tcp2_socket];
let mut iface = EthernetInterface::new(device, arp_cache,
hardware_addr, protocol_addrs, sockets);
let mut tcp_6969_connected = false;
loop {
// udp:6969: respond "yo dawg"
{
let socket: &mut UdpSocket = iface.sockets()[0].as_socket();
let client = match socket.recv() {
Ok((endpoint, data)) => {
debug!("udp recv data: {:?} from {}",
debug!("udp:6969 recv data: {:?} from {}",
str::from_utf8(data.as_ref()).unwrap(), endpoint);
Some(endpoint)
}
@ -77,28 +82,46 @@ fn main() {
None
}
Err(e) => {
debug!("udp recv error: {}", e);
debug!("udp:6969 recv error: {}", e);
None
}
};
if let Some(endpoint) = client {
let data = b"yo dawg";
debug!("udp send data: {:?}",
let data = b"yo dawg\n";
debug!("udp:6969 send data: {:?}",
str::from_utf8(data.as_ref()).unwrap());
socket.send_slice(endpoint, data).unwrap()
}
}
// tcp:6969: respond "yo dawg"
{
let socket: &mut TcpSocket = iface.sockets()[1].as_socket();
if !socket.is_open() {
socket.listen(endpoint).unwrap()
socket.listen(6969).unwrap();
}
if socket.can_send() {
let data = b"yo dawg\n";
debug!("tcp:6969 send data: {:?}",
str::from_utf8(data.as_ref()).unwrap());
socket.send_slice(data).unwrap();
debug!("tcp:6969 close");
socket.close();
}
}
// tcp:6970: echo with reverse
{
let socket: &mut TcpSocket = iface.sockets()[2].as_socket();
if !socket.is_open() {
socket.listen(6970).unwrap()
}
if socket.is_connected() && !tcp_6969_connected {
debug!("tcp connected");
debug!("tcp:6970 connected");
} else if !socket.is_connected() && tcp_6969_connected {
debug!("tcp disconnected");
debug!("tcp:6970 disconnected");
}
tcp_6969_connected = socket.is_connected();
@ -106,7 +129,7 @@ fn main() {
let data = {
let mut data = socket.recv(128).unwrap().to_owned();
if data.len() > 0 {
debug!("tcp recv data: {:?}",
debug!("tcp:6970 recv data: {:?}",
str::from_utf8(data.as_ref()).unwrap_or("(invalid utf8)"));
data = data.split(|&b| b == b'\n').collect::<Vec<_>>().concat();
data.reverse();
@ -115,13 +138,13 @@ fn main() {
data
};
if socket.can_send() && data.len() > 0 {
debug!("tcp send data: {:?}",
debug!("tcp:6970 send data: {:?}",
str::from_utf8(data.as_ref()).unwrap_or("(invalid utf8)"));
socket.send_slice(&data[..]).unwrap();
}
} else if socket.can_send() {
debug!("tcp:6970 close");
socket.close();
debug!("tcp closed")
}
}

116
src/socket/tcp.rs
View File

@ -249,9 +249,10 @@ impl<'a> TcpSocket<'a> {
/// Start listening on the given endpoint.
///
/// This function returns an error if the socket was open; see [is_open](#method.is_open).
pub fn listen(&mut self, endpoint: IpEndpoint) -> Result<(), ()> {
pub fn listen<T: Into<IpEndpoint>>(&mut self, endpoint: T) -> Result<(), ()> {
if self.is_open() { return Err(()) }
let endpoint = endpoint.into();
self.listen_address = endpoint.addr;
self.local_endpoint = endpoint;
self.remote_endpoint = IpEndpoint::default();
@ -507,8 +508,8 @@ impl<'a> TcpSocket<'a> {
let control_len = match state {
// In SYN-SENT or SYN-RECEIVED, we've just sent a SYN.
State::SynSent | State::SynReceived => 1,
// In FIN-WAIT-1 or LAST-ACK, we've just sent a FIN.
State::FinWait1 | State::LastAck => 1,
// In FIN-WAIT-1, LAST-ACK, or CLOSING, we've just sent a FIN.
State::FinWait1 | State::LastAck | State::Closing => 1,
// In all other states we've already got acknowledgemetns for
// all of the control flags we sent.
_ => 0
@ -625,9 +626,9 @@ impl<'a> TcpSocket<'a> {
// ACK packets in CLOSING state change it to TIME-WAIT.
(State::Closing, TcpRepr { control: TcpControl::None, .. }) => {
// Clear the remote endpoint, or we'll send an ACK there.
self.remote_endpoint = IpEndpoint::default();
self.local_seq_no += 1;
self.set_state(State::TimeWait);
self.retransmit.reset();
}
// ACK packets in CLOSE-WAIT state do nothing.
@ -696,8 +697,8 @@ impl<'a> TcpSocket<'a> {
let mut should_send = false;
match self.state {
// We never transmit anything in the CLOSED, LISTEN, TIME-WAIT or FIN-WAIT-2 states.
State::Closed | State::Listen | State::TimeWait | State::FinWait2 => {
// We never transmit anything in the CLOSED, LISTEN, or FIN-WAIT-2 states.
State::Closed | State::Listen | State::FinWait2 => {
return Err(Error::Exhausted)
}
@ -723,11 +724,11 @@ impl<'a> TcpSocket<'a> {
}
// We transmit data in the ESTABLISHED state,
// ACK in CLOSE-WAIT and CLOSING states,
// ACK in CLOSE-WAIT, CLOSING, and TIME-WAIT states,
// FIN in FIN-WAIT-1 and LAST-ACK states.
State::Established |
State::CloseWait | State::LastAck |
State::FinWait1 | State::Closing => {
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...
@ -1375,7 +1376,6 @@ mod test {
..SEND_TEMPL
}]);
assert_eq!(s.state, State::TimeWait);
assert!(!s.remote_endpoint.is_unspecified());
}
#[test]
@ -1391,7 +1391,7 @@ mod test {
fn socket_closing() -> TcpSocket<'static> {
let mut s = socket_fin_wait_1();
s.state = State::Closing;
s.local_seq_no = LOCAL_SEQ + 1 + 1;
s.local_seq_no = LOCAL_SEQ + 1;
s.remote_seq_no = REMOTE_SEQ + 1 + 1;
s
}
@ -1400,7 +1400,7 @@ mod test {
fn test_closing_ack_fin() {
let mut s = socket_closing();
recv!(s, [TcpRepr {
seq_number: LOCAL_SEQ + 1 + 1,
seq_number: LOCAL_SEQ + 1,
ack_number: Some(REMOTE_SEQ + 1 + 1),
..RECV_TEMPL
}]);
@ -1410,7 +1410,6 @@ mod test {
..SEND_TEMPL
}]);
assert_eq!(s.state, State::TimeWait);
assert!(s.remote_endpoint.is_unspecified());
}
#[test]
@ -1423,17 +1422,35 @@ mod test {
// =========================================================================================//
// Tests for the TIME-WAIT state.
// =========================================================================================//
fn socket_time_wait() -> TcpSocket<'static> {
fn socket_time_wait(from_closing: bool) -> TcpSocket<'static> {
let mut s = socket_fin_wait_2();
s.state = State::TimeWait;
s.remote_seq_no = REMOTE_SEQ + 1 + 1;
s.remote_last_ack = REMOTE_SEQ + 1 + 1;
if from_closing {
s.remote_last_ack = REMOTE_SEQ + 1 + 1;
}
s
}
#[test]
fn test_time_wait_from_fin_wait_2_ack() {
let mut s = socket_time_wait(false);
recv!(s, [TcpRepr {
seq_number: LOCAL_SEQ + 1 + 1,
ack_number: Some(REMOTE_SEQ + 1 + 1),
..RECV_TEMPL
}]);
}
#[test]
fn test_time_wait_from_closing_no_ack() {
let mut s = socket_time_wait(true);
recv!(s, []);
}
#[test]
fn test_time_wait_close() {
let mut s = socket_time_wait();
let mut s = socket_time_wait(false);
s.close();
assert_eq!(s.state, State::TimeWait);
}
@ -1573,5 +1590,70 @@ mod test {
ack_number: Some(LOCAL_SEQ + 1 + 1),
..SEND_TEMPL
}]);
assert_eq!(s.state, State::Closed);
}
#[test]
fn test_local_close() {
let mut s = socket_established();
s.close();
assert_eq!(s.state, State::FinWait1);
recv!(s, [TcpRepr {
control: TcpControl::Fin,
seq_number: LOCAL_SEQ + 1,
ack_number: Some(REMOTE_SEQ + 1),
..RECV_TEMPL
}]);
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 {
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,
ack_number: Some(REMOTE_SEQ + 1 + 1),
..RECV_TEMPL
}]);
}
#[test]
fn test_simultaneous_close() {
let mut s = socket_established();
s.close();
assert_eq!(s.state, State::FinWait1);
recv!(s, [TcpRepr { // this is logically located...
control: TcpControl::Fin,
seq_number: LOCAL_SEQ + 1,
ack_number: Some(REMOTE_SEQ + 1),
..RECV_TEMPL
}]);
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,
ack_number: Some(REMOTE_SEQ + 1 + 1),
..RECV_TEMPL
}]);
// ... at this point
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, []);
}
}

8
src/wire/ip.rs
View File

@ -78,6 +78,8 @@ impl fmt::Display for Address {
}
/// An internet endpoint address.
///
/// An endpoint can be constructed from a port, in which case the address is unspecified.
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default)]
pub struct Endpoint {
pub addr: Address,
@ -104,6 +106,12 @@ impl fmt::Display for Endpoint {
}
}
impl From<u16> for Endpoint {
fn from(port: u16) -> Endpoint {
Endpoint { addr: Address::Unspecified, port: port }
}
}
/// An IP packet representation.
///
/// This enum abstracts the various versions of IP packets. It either contains a concrete