// Heads up! Before working on this file you should read, at least, RFC 793 and // the parts of RFC 1122 that discuss TCP. Consult RFC 7414 when implementing // a new feature. use core::fmt::Display; #[cfg(feature = "async")] use core::task::Waker; use core::{cmp, fmt, mem}; #[cfg(feature = "async")] use crate::socket::WakerRegistration; use crate::socket::{Context, PollAt}; use crate::storage::{Assembler, RingBuffer}; use crate::time::{Duration, Instant}; use crate::wire::{ IpAddress, IpEndpoint, IpListenEndpoint, IpProtocol, IpRepr, TcpControl, TcpRepr, TcpSeqNumber, TCP_HEADER_LEN, }; macro_rules! tcp_trace { ($($arg:expr),*) => (net_log!(trace, $($arg),*)); } /// Error returned by [`Socket::listen`] #[derive(Debug, PartialEq, Eq, Clone, Copy)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] pub enum ListenError { InvalidState, Unaddressable, } /// Error returned by [`Socket::connect`] #[derive(Debug, PartialEq, Eq, Clone, Copy)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] pub enum ConnectError { InvalidState, Unaddressable, } /// Error returned by [`Socket::send`] #[derive(Debug, PartialEq, Eq, Clone, Copy)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] pub enum SendError { InvalidState, } /// Error returned by [`Socket::recv`] #[derive(Debug, PartialEq, Eq, Clone, Copy)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] pub enum RecvError { InvalidState, Finished, } /// A TCP socket ring buffer. pub type SocketBuffer<'a> = RingBuffer<'a, u8>; /// The state of a TCP socket, according to [RFC 793]. /// /// [RFC 793]: https://tools.ietf.org/html/rfc793 #[derive(Debug, PartialEq, Eq, Clone, Copy)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] pub enum State { Closed, Listen, SynSent, SynReceived, Established, FinWait1, FinWait2, CloseWait, Closing, LastAck, TimeWait, } impl fmt::Display for State { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match *self { State::Closed => write!(f, "CLOSED"), State::Listen => write!(f, "LISTEN"), State::SynSent => write!(f, "SYN-SENT"), State::SynReceived => write!(f, "SYN-RECEIVED"), State::Established => write!(f, "ESTABLISHED"), State::FinWait1 => write!(f, "FIN-WAIT-1"), State::FinWait2 => write!(f, "FIN-WAIT-2"), State::CloseWait => write!(f, "CLOSE-WAIT"), State::Closing => write!(f, "CLOSING"), State::LastAck => write!(f, "LAST-ACK"), State::TimeWait => write!(f, "TIME-WAIT"), } } } // Conservative initial RTT estimate. const RTTE_INITIAL_RTT: u32 = 300; const RTTE_INITIAL_DEV: u32 = 100; // Minimum "safety margin" for the RTO that kicks in when the // variance gets very low. const RTTE_MIN_MARGIN: u32 = 5; const RTTE_MIN_RTO: u32 = 10; const RTTE_MAX_RTO: u32 = 10000; #[derive(Debug, Clone, Copy)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] struct RttEstimator { // Using u32 instead of Duration to save space (Duration is i64) rtt: u32, deviation: u32, timestamp: Option<(Instant, TcpSeqNumber)>, max_seq_sent: Option, rto_count: u8, } impl Default for RttEstimator { fn default() -> Self { Self { rtt: RTTE_INITIAL_RTT, deviation: RTTE_INITIAL_DEV, timestamp: None, max_seq_sent: None, rto_count: 0, } } } impl RttEstimator { fn retransmission_timeout(&self) -> Duration { let margin = RTTE_MIN_MARGIN.max(self.deviation * 4); let ms = (self.rtt + margin).clamp(RTTE_MIN_RTO, RTTE_MAX_RTO); Duration::from_millis(ms as u64) } fn sample(&mut self, new_rtt: u32) { // "Congestion Avoidance and Control", Van Jacobson, Michael J. Karels, 1988 self.rtt = (self.rtt * 7 + new_rtt + 7) / 8; let diff = (self.rtt as i32 - new_rtt as i32).unsigned_abs(); self.deviation = (self.deviation * 3 + diff + 3) / 4; self.rto_count = 0; let rto = self.retransmission_timeout().total_millis(); tcp_trace!( "rtte: sample={:?} rtt={:?} dev={:?} rto={:?}", new_rtt, self.rtt, self.deviation, rto ); } fn on_send(&mut self, timestamp: Instant, seq: TcpSeqNumber) { if self .max_seq_sent .map(|max_seq_sent| seq > max_seq_sent) .unwrap_or(true) { self.max_seq_sent = Some(seq); if self.timestamp.is_none() { self.timestamp = Some((timestamp, seq)); tcp_trace!("rtte: sampling at seq={:?}", seq); } } } fn on_ack(&mut self, timestamp: Instant, seq: TcpSeqNumber) { if let Some((sent_timestamp, sent_seq)) = self.timestamp { if seq >= sent_seq { self.sample((timestamp - sent_timestamp).total_millis() as u32); self.timestamp = None; } } } fn on_retransmit(&mut self) { if self.timestamp.is_some() { tcp_trace!("rtte: abort sampling due to retransmit"); } self.timestamp = None; self.rto_count = self.rto_count.saturating_add(1); if self.rto_count >= 3 { // This happens in 2 scenarios: // - The RTT is higher than the initial estimate // - The network conditions change, suddenly making the RTT much higher // In these cases, the estimator can get stuck, because it can't sample because // all packets sent would incur a retransmit. To avoid this, force an estimate // increase if we see 3 consecutive retransmissions without any successful sample. self.rto_count = 0; self.rtt = RTTE_MAX_RTO.min(self.rtt * 2); let rto = self.retransmission_timeout().total_millis(); tcp_trace!( "rtte: too many retransmissions, increasing: rtt={:?} dev={:?} rto={:?}", self.rtt, self.deviation, rto ); } } } #[derive(Debug, Clone, Copy, PartialEq)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] enum Timer { Idle { keep_alive_at: Option, }, Retransmit { expires_at: Instant, delay: Duration, }, FastRetransmit, Close { expires_at: Instant, }, } const ACK_DELAY_DEFAULT: Duration = Duration::from_millis(10); const CLOSE_DELAY: Duration = Duration::from_millis(10_000); impl Timer { fn new() -> Timer { Timer::Idle { keep_alive_at: None, } } fn should_keep_alive(&self, timestamp: Instant) -> bool { match *self { Timer::Idle { keep_alive_at: Some(keep_alive_at), } if timestamp >= keep_alive_at => true, _ => false, } } fn should_retransmit(&self, timestamp: Instant) -> Option { match *self { Timer::Retransmit { expires_at, delay } if timestamp >= expires_at => { Some(timestamp - expires_at + delay) } Timer::FastRetransmit => Some(Duration::from_millis(0)), _ => None, } } fn should_close(&self, timestamp: Instant) -> bool { match *self { Timer::Close { expires_at } if timestamp >= expires_at => true, _ => false, } } fn poll_at(&self) -> PollAt { match *self { Timer::Idle { keep_alive_at: Some(keep_alive_at), } => PollAt::Time(keep_alive_at), Timer::Idle { keep_alive_at: None, } => PollAt::Ingress, Timer::Retransmit { expires_at, .. } => PollAt::Time(expires_at), Timer::FastRetransmit => PollAt::Now, Timer::Close { expires_at } => PollAt::Time(expires_at), } } fn set_for_idle(&mut self, timestamp: Instant, interval: Option) { *self = Timer::Idle { keep_alive_at: interval.map(|interval| timestamp + interval), } } fn set_keep_alive(&mut self) { if let Timer::Idle { keep_alive_at } = self { if keep_alive_at.is_none() { *keep_alive_at = Some(Instant::from_millis(0)) } } } fn rewind_keep_alive(&mut self, timestamp: Instant, interval: Option) { if let Timer::Idle { keep_alive_at } = self { *keep_alive_at = interval.map(|interval| timestamp + interval) } } fn set_for_retransmit(&mut self, timestamp: Instant, delay: Duration) { match *self { Timer::Idle { .. } | Timer::FastRetransmit { .. } => { *self = Timer::Retransmit { expires_at: timestamp + delay, delay, } } Timer::Retransmit { expires_at, delay } if timestamp >= expires_at => { *self = Timer::Retransmit { expires_at: timestamp + delay, delay: delay * 2, } } Timer::Retransmit { .. } => (), Timer::Close { .. } => (), } } fn set_for_fast_retransmit(&mut self) { *self = Timer::FastRetransmit } fn set_for_close(&mut self, timestamp: Instant) { *self = Timer::Close { expires_at: timestamp + CLOSE_DELAY, } } fn is_retransmit(&self) -> bool { match *self { Timer::Retransmit { .. } | Timer::FastRetransmit => true, _ => false, } } } #[derive(Debug, PartialEq, Eq, Clone, Copy)] enum AckDelayTimer { Idle, Waiting(Instant), Immediate, } #[derive(Debug, Copy, Clone, Eq, PartialEq)] #[cfg_attr(feature = "defmt", derive(defmt::Format))] struct Tuple { local: IpEndpoint, remote: IpEndpoint, } impl Display for Tuple { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{}:{}", self.local, self.remote) } } /// A Transmission Control Protocol socket. /// /// A TCP socket may passively listen for connections or actively connect to another endpoint. /// Note that, for listening sockets, there is no "backlog"; to be able to simultaneously /// accept several connections, as many sockets must be allocated, or any new connection /// attempts will be reset. #[derive(Debug)] pub struct Socket<'a> { state: State, timer: Timer, rtte: RttEstimator, assembler: Assembler, rx_buffer: SocketBuffer<'a>, rx_fin_received: bool, tx_buffer: SocketBuffer<'a>, /// Interval after which, if no inbound packets are received, the connection is aborted. timeout: Option, /// Interval at which keep-alive packets will be sent. keep_alive: Option, /// The time-to-live (IPv4) or hop limit (IPv6) value used in outgoing packets. hop_limit: Option, /// Address passed to listen(). Listen address is set when listen() is called and /// used every time the socket is reset back to the LISTEN state. listen_endpoint: IpListenEndpoint, /// Current 4-tuple (local and remote endpoints). tuple: Option, /// The sequence number corresponding to the beginning of the transmit buffer. /// I.e. an ACK(local_seq_no+n) packet removes n bytes from the transmit buffer. local_seq_no: TcpSeqNumber, /// The sequence number corresponding to the beginning of the receive buffer. /// I.e. userspace reading n bytes adds n to remote_seq_no. remote_seq_no: TcpSeqNumber, /// The last sequence number sent. /// I.e. in an idle socket, local_seq_no+tx_buffer.len(). remote_last_seq: TcpSeqNumber, /// The last acknowledgement number sent. /// I.e. in an idle socket, remote_seq_no+rx_buffer.len(). remote_last_ack: Option, /// The last window length sent. remote_last_win: u16, /// 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 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, /// Whether or not the remote supports selective ACK as described in RFC 2018. remote_has_sack: bool, /// The maximum number of data octets that the remote side may receive. remote_mss: usize, /// The timestamp of the last packet received. remote_last_ts: Option, /// The sequence number of the last packet received, used for sACK local_rx_last_seq: Option, /// The ACK number of the last packet received. local_rx_last_ack: Option, /// The number of packets received directly after /// each other which have the same ACK number. local_rx_dup_acks: u8, /// Duration for Delayed ACK. If None no ACKs will be delayed. ack_delay: Option, /// Delayed ack timer. If set, packets containing exclusively /// ACK or window updates (ie, no data) won't be sent until expiry. ack_delay_timer: AckDelayTimer, /// Used for rate-limiting: No more challenge ACKs will be sent until this instant. challenge_ack_timer: Instant, /// Nagle's Algorithm enabled. nagle: bool, #[cfg(feature = "async")] rx_waker: WakerRegistration, #[cfg(feature = "async")] tx_waker: WakerRegistration, } const DEFAULT_MSS: usize = 536; impl<'a> Socket<'a> { #[allow(unused_comparisons)] // small usize platforms always pass rx_capacity check /// Create a socket using the given buffers. pub fn new(rx_buffer: T, tx_buffer: T) -> Socket<'a> where T: Into>, { let (rx_buffer, tx_buffer) = (rx_buffer.into(), tx_buffer.into()); let rx_capacity = rx_buffer.capacity(); // From RFC 1323: // [...] the above constraints imply that 2 * the max window size must be less // than 2**31 [...] Thus, the shift count must be limited to 14 (which allows // windows of 2**30 = 1 Gbyte). if rx_capacity > (1 << 30) { panic!("receiving buffer too large, cannot exceed 1 GiB") } let rx_cap_log2 = mem::size_of::() * 8 - rx_capacity.leading_zeros() as usize; Socket { state: State::Closed, timer: Timer::new(), rtte: RttEstimator::default(), assembler: Assembler::new(), tx_buffer, rx_buffer, rx_fin_received: false, timeout: None, keep_alive: None, hop_limit: None, listen_endpoint: IpListenEndpoint::default(), tuple: None, local_seq_no: TcpSeqNumber::default(), remote_seq_no: TcpSeqNumber::default(), remote_last_seq: TcpSeqNumber::default(), remote_last_ack: None, remote_last_win: 0, remote_win_len: 0, remote_win_shift: rx_cap_log2.saturating_sub(16) as u8, remote_win_scale: None, remote_has_sack: false, remote_mss: DEFAULT_MSS, remote_last_ts: None, local_rx_last_ack: None, local_rx_last_seq: None, local_rx_dup_acks: 0, ack_delay: Some(ACK_DELAY_DEFAULT), ack_delay_timer: AckDelayTimer::Idle, challenge_ack_timer: Instant::from_secs(0), nagle: true, #[cfg(feature = "async")] rx_waker: WakerRegistration::new(), #[cfg(feature = "async")] tx_waker: WakerRegistration::new(), } } /// Register a waker for receive operations. /// /// The waker is woken on state changes that might affect the return value /// of `recv` method calls, such as receiving data, or the socket closing. /// /// Notes: /// /// - Only one waker can be registered at a time. If another waker was previously registered, /// it is overwritten and will no longer be woken. /// - The Waker is woken only once. Once woken, you must register it again to receive more wakes. /// - "Spurious wakes" are allowed: a wake doesn't guarantee the result of `recv` has /// necessarily changed. #[cfg(feature = "async")] pub fn register_recv_waker(&mut self, waker: &Waker) { self.rx_waker.register(waker) } /// Register a waker for send operations. /// /// The waker is woken on state changes that might affect the return value /// of `send` method calls, such as space becoming available in the transmit /// buffer, or the socket closing. /// /// Notes: /// /// - Only one waker can be registered at a time. If another waker was previously registered, /// it is overwritten and will no longer be woken. /// - The Waker is woken only once. Once woken, you must register it again to receive more wakes. /// - "Spurious wakes" are allowed: a wake doesn't guarantee the result of `send` has /// necessarily changed. #[cfg(feature = "async")] pub fn register_send_waker(&mut self, waker: &Waker) { self.tx_waker.register(waker) } /// Return the timeout duration. /// /// See also the [set_timeout](#method.set_timeout) method. pub fn timeout(&self) -> Option { self.timeout } /// Return the ACK delay duration. /// /// See also the [set_ack_delay](#method.set_ack_delay) method. pub fn ack_delay(&self) -> Option { self.ack_delay } /// Return whether Nagle's Algorithm is enabled. /// /// See also the [set_nagle_enabled](#method.set_nagle_enabled) method. pub fn nagle_enabled(&self) -> bool { self.nagle } /// Return the current window field value, including scaling according to RFC 1323. /// /// Used in internal calculations as well as packet generation. /// #[inline] fn scaled_window(&self) -> u16 { cmp::min( self.rx_buffer.window() >> self.remote_win_shift as usize, (1 << 16) - 1, ) as u16 } /// Set the timeout duration. /// /// A socket with a timeout duration set will abort the connection if either of the following /// occurs: /// /// * After a [connect](#method.connect) call, the remote endpoint does not respond within /// the specified duration; /// * After establishing a connection, there is data in the transmit buffer and the remote /// endpoint exceeds the specified duration between any two packets it sends; /// * After enabling [keep-alive](#method.set_keep_alive), the remote endpoint exceeds /// the specified duration between any two packets it sends. pub fn set_timeout(&mut self, duration: Option) { self.timeout = duration } /// Set the ACK delay duration. /// /// By default, the ACK delay is set to 10ms. pub fn set_ack_delay(&mut self, duration: Option) { self.ack_delay = duration } /// Enable or disable Nagle's Algorithm. /// /// Also known as "tinygram prevention". By default, it is enabled. /// Disabling it is equivalent to Linux's TCP_NODELAY flag. /// /// When enabled, Nagle's Algorithm prevents sending segments smaller than MSS if /// there is data in flight (sent but not acknowledged). In other words, it ensures /// at most only one segment smaller than MSS is in flight at a time. /// /// It ensures better network utilization by preventing sending many very small packets, /// at the cost of increased latency in some situations, particularly when the remote peer /// has ACK delay enabled. pub fn set_nagle_enabled(&mut self, enabled: bool) { self.nagle = enabled } /// Return the keep-alive interval. /// /// See also the [set_keep_alive](#method.set_keep_alive) method. pub fn keep_alive(&self) -> Option { self.keep_alive } /// Set the keep-alive interval. /// /// An idle socket with a keep-alive interval set will transmit a "keep-alive ACK" packet /// every time it receives no communication during that interval. As a result, three things /// may happen: /// /// * The remote endpoint is fine and answers with an ACK packet. /// * The remote endpoint has rebooted and answers with an RST packet. /// * The remote endpoint has crashed and does not answer. /// /// The keep-alive functionality together with the timeout functionality allows to react /// to these error conditions. pub fn set_keep_alive(&mut self, interval: Option) { self.keep_alive = interval; if self.keep_alive.is_some() { // If the connection is idle and we've just set the option, it would not take effect // until the next packet, unless we wind up the timer explicitly. self.timer.set_keep_alive(); } } /// Return the time-to-live (IPv4) or hop limit (IPv6) value used in outgoing packets. /// /// See also the [set_hop_limit](#method.set_hop_limit) method pub fn hop_limit(&self) -> Option { self.hop_limit } /// Set the time-to-live (IPv4) or hop limit (IPv6) value used in outgoing packets. /// /// A socket without an explicitly set hop limit value uses the default [IANA recommended] /// value (64). /// /// # Panics /// /// This function panics if a hop limit value of 0 is given. See [RFC 1122 § 3.2.1.7]. /// /// [IANA recommended]: https://www.iana.org/assignments/ip-parameters/ip-parameters.xhtml /// [RFC 1122 § 3.2.1.7]: https://tools.ietf.org/html/rfc1122#section-3.2.1.7 pub fn set_hop_limit(&mut self, hop_limit: Option) { // A host MUST NOT send a datagram with a hop limit value of 0 if let Some(0) = hop_limit { panic!("the time-to-live value of a packet must not be zero") } self.hop_limit = hop_limit } /// Return the local endpoint, or None if not connected. #[inline] pub fn local_endpoint(&self) -> Option { Some(self.tuple?.local) } /// Return the remote endpoint, or None if not connected. #[inline] pub fn remote_endpoint(&self) -> Option { Some(self.tuple?.remote) } /// Return the connection state, in terms of the TCP state machine. #[inline] pub fn state(&self) -> State { self.state } fn reset(&mut self) { let rx_cap_log2 = mem::size_of::() * 8 - self.rx_buffer.capacity().leading_zeros() as usize; self.state = State::Closed; self.timer = Timer::new(); self.rtte = RttEstimator::default(); self.assembler = Assembler::new(); self.tx_buffer.clear(); self.rx_buffer.clear(); self.rx_fin_received = false; self.listen_endpoint = IpListenEndpoint::default(); self.tuple = None; self.local_seq_no = TcpSeqNumber::default(); self.remote_seq_no = TcpSeqNumber::default(); self.remote_last_seq = TcpSeqNumber::default(); self.remote_last_ack = None; self.remote_last_win = 0; self.remote_win_len = 0; self.remote_win_scale = None; self.remote_win_shift = rx_cap_log2.saturating_sub(16) as u8; self.remote_mss = DEFAULT_MSS; self.remote_last_ts = None; self.ack_delay_timer = AckDelayTimer::Idle; self.challenge_ack_timer = Instant::from_secs(0); #[cfg(feature = "async")] { self.rx_waker.wake(); self.tx_waker.wake(); } } /// Start listening on the given endpoint. /// /// This function returns `Err(Error::Illegal)` if the socket was already open /// (see [is_open](#method.is_open)), and `Err(Error::Unaddressable)` /// if the port in the given endpoint is zero. pub fn listen(&mut self, local_endpoint: T) -> Result<(), ListenError> where T: Into, { let local_endpoint = local_endpoint.into(); if local_endpoint.port == 0 { return Err(ListenError::Unaddressable); } if self.is_open() { return Err(ListenError::InvalidState); } self.reset(); self.listen_endpoint = local_endpoint; self.tuple = None; self.set_state(State::Listen); Ok(()) } /// Connect to a given endpoint. /// /// The local port must be provided explicitly. Assuming `fn get_ephemeral_port() -> u16` /// allocates a port between 49152 and 65535, a connection may be established as follows: /// /// ```no_run /// # #[cfg(all( /// # feature = "medium-ethernet", /// # feature = "proto-ipv4", /// # ))] /// # { /// # use smoltcp::socket::tcp::{Socket, SocketBuffer}; /// # use smoltcp::iface::Interface; /// # use smoltcp::wire::IpAddress; /// # /// # fn get_ephemeral_port() -> u16 { /// # 49152 /// # } /// # /// # let mut socket = Socket::new( /// # SocketBuffer::new(vec![0; 1200]), /// # SocketBuffer::new(vec![0; 1200]) /// # ); /// # /// # let mut iface: Interface = todo!(); /// # /// socket.connect( /// iface.context(), /// (IpAddress::v4(10, 0, 0, 1), 80), /// get_ephemeral_port() /// ).unwrap(); /// # } /// ``` /// /// The local address may optionally be provided. /// /// This function returns an error if the socket was open; see [is_open](#method.is_open). /// It also returns an error if the local or remote port is zero, or if the remote address /// is unspecified. pub fn connect( &mut self, cx: &mut Context, remote_endpoint: T, local_endpoint: U, ) -> Result<(), ConnectError> where T: Into, U: Into, { let remote_endpoint: IpEndpoint = remote_endpoint.into(); let local_endpoint: IpListenEndpoint = local_endpoint.into(); if self.is_open() { return Err(ConnectError::InvalidState); } if remote_endpoint.port == 0 || remote_endpoint.addr.is_unspecified() { return Err(ConnectError::Unaddressable); } if local_endpoint.port == 0 { return Err(ConnectError::Unaddressable); } // If local address is not provided, choose it automatically. let local_endpoint = IpEndpoint { addr: match local_endpoint.addr { Some(addr) => { if addr.is_unspecified() { return Err(ConnectError::Unaddressable); } addr } None => cx .get_source_address(remote_endpoint.addr) .ok_or(ConnectError::Unaddressable)?, }, port: local_endpoint.port, }; if local_endpoint.addr.version() != remote_endpoint.addr.version() { return Err(ConnectError::Unaddressable); } self.reset(); self.tuple = Some(Tuple { local: local_endpoint, remote: remote_endpoint, }); self.set_state(State::SynSent); let seq = Self::random_seq_no(cx); self.local_seq_no = seq; self.remote_last_seq = seq; Ok(()) } #[cfg(test)] fn random_seq_no(_cx: &mut Context) -> TcpSeqNumber { TcpSeqNumber(10000) } #[cfg(not(test))] fn random_seq_no(cx: &mut Context) -> TcpSeqNumber { TcpSeqNumber(cx.rand().rand_u32() as i32) } /// Close the transmit half of the full-duplex connection. /// /// Note that there is no corresponding function for the receive half of the full-duplex /// connection; only the remote end can close it. If you no longer wish to receive any /// data and would like to reuse the socket right away, use [abort](#method.abort). pub fn close(&mut self) { match self.state { // In the LISTEN state there is no established connection. State::Listen => self.set_state(State::Closed), // In the SYN-SENT state the remote endpoint is not yet synchronized and, upon // receiving an RST, will abort the connection. State::SynSent => self.set_state(State::Closed), // In the SYN-RECEIVED, ESTABLISHED and CLOSE-WAIT states the transmit half // of the connection is open, and needs to be explicitly closed with a FIN. State::SynReceived | State::Established => self.set_state(State::FinWait1), State::CloseWait => self.set_state(State::LastAck), // In the FIN-WAIT-1, FIN-WAIT-2, CLOSING, LAST-ACK, TIME-WAIT and CLOSED states, // the transmit half of the connection is already closed, and no further // action is needed. State::FinWait1 | State::FinWait2 | State::Closing | State::TimeWait | State::LastAck | State::Closed => (), } } /// Aborts the connection, if any. /// /// This function instantly closes the socket. One reset packet will be sent to the remote /// endpoint. /// /// In terms of the TCP state machine, the socket may be in any state and is moved to /// the `CLOSED` state. pub fn abort(&mut self) { self.set_state(State::Closed); } /// Return whether the socket is passively listening for incoming connections. /// /// In terms of the TCP state machine, the socket must be in the `LISTEN` state. #[inline] pub fn is_listening(&self) -> bool { match self.state { State::Listen => true, _ => false, } } /// Return whether the socket is open. /// /// This function returns true if the socket will process incoming or dispatch outgoing /// packets. Note that this does not mean that it is possible to send or receive data through /// the socket; for that, use [can_send](#method.can_send) or [can_recv](#method.can_recv). /// /// In terms of the TCP state machine, the socket must not be in the `CLOSED` /// or `TIME-WAIT` states. #[inline] pub fn is_open(&self) -> bool { match self.state { State::Closed => false, State::TimeWait => false, _ => true, } } /// Return whether a connection is active. /// /// This function returns true if the socket is actively exchanging packets with /// a remote endpoint. Note that this does not mean that it is possible to send or receive /// data through the socket; for that, use [can_send](#method.can_send) or /// [can_recv](#method.can_recv). /// /// If a connection is established, [abort](#method.close) will send a reset to /// the remote endpoint. /// /// In terms of the TCP state machine, the socket must not be in the `CLOSED`, `TIME-WAIT`, /// or `LISTEN` state. #[inline] pub fn is_active(&self) -> bool { match self.state { State::Closed => false, State::TimeWait => false, State::Listen => false, _ => true, } } /// Return whether the transmit half of the full-duplex connection is open. /// /// This function returns true if it's possible to send data and have it arrive /// to the remote endpoint. However, it does not make any guarantees about the state /// of the transmit buffer, and even if it returns true, [send](#method.send) may /// not be able to enqueue any octets. /// /// In terms of the TCP state machine, the socket must be in the `ESTABLISHED` or /// `CLOSE-WAIT` state. #[inline] pub fn may_send(&self) -> bool { match self.state { State::Established => true, // In CLOSE-WAIT, the remote endpoint has closed our receive half of the connection // but we still can transmit indefinitely. State::CloseWait => true, _ => false, } } /// Return whether the receive half of the full-duplex connection is open. /// /// This function returns true if it's possible to receive data from the remote endpoint. /// It will return true while there is data in the receive buffer, and if there isn't, /// as long as the remote endpoint has not closed the connection. /// /// In terms of the TCP state machine, the socket must be in the `ESTABLISHED`, /// `FIN-WAIT-1`, or `FIN-WAIT-2` state, or have data in the receive buffer instead. #[inline] pub fn may_recv(&self) -> bool { match self.state { State::Established => true, // In FIN-WAIT-1/2, we have closed our transmit half of the connection but // we still can receive indefinitely. State::FinWait1 | State::FinWait2 => true, // If we have something in the receive buffer, we can receive that. _ if !self.rx_buffer.is_empty() => true, _ => false, } } /// Check whether the transmit half of the full-duplex connection is open /// (see [may_send](#method.may_send)), and the transmit buffer is not full. #[inline] pub fn can_send(&self) -> bool { if !self.may_send() { return false; } !self.tx_buffer.is_full() } /// Return the maximum number of bytes inside the recv buffer. #[inline] pub fn recv_capacity(&self) -> usize { self.rx_buffer.capacity() } /// Return the maximum number of bytes inside the transmit buffer. #[inline] pub fn send_capacity(&self) -> usize { self.tx_buffer.capacity() } /// Check whether the receive half of the full-duplex connection buffer is open /// (see [may_recv](#method.may_recv)), and the receive buffer is not empty. #[inline] pub fn can_recv(&self) -> bool { if !self.may_recv() { return false; } !self.rx_buffer.is_empty() } fn send_impl<'b, F, R>(&'b mut self, f: F) -> Result where F: FnOnce(&'b mut SocketBuffer<'a>) -> (usize, R), { if !self.may_send() { return Err(SendError::InvalidState); } // The connection might have been idle for a long time, and so remote_last_ts // would be far in the past. Unless we clear it here, we'll abort the connection // down over in dispatch() by erroneously detecting it as timed out. if self.tx_buffer.is_empty() { self.remote_last_ts = None } let _old_length = self.tx_buffer.len(); let (size, result) = f(&mut self.tx_buffer); if size > 0 { #[cfg(any(test, feature = "verbose"))] tcp_trace!( "tx buffer: enqueueing {} octets (now {})", size, _old_length + size ); } Ok(result) } /// Call `f` with the largest contiguous slice of octets in the transmit buffer, /// and enqueue the amount of elements returned by `f`. /// /// This function returns `Err(Error::Illegal)` if the transmit half of /// the connection is not open; see [may_send](#method.may_send). pub fn send<'b, F, R>(&'b mut self, f: F) -> Result where F: FnOnce(&'b mut [u8]) -> (usize, R), { self.send_impl(|tx_buffer| tx_buffer.enqueue_many_with(f)) } /// Enqueue a sequence of octets to be sent, and fill it from a slice. /// /// This function returns the amount of octets actually enqueued, which is limited /// by the amount of free space in the transmit buffer; down to zero. /// /// See also [send](#method.send). pub fn send_slice(&mut self, data: &[u8]) -> Result { self.send_impl(|tx_buffer| { let size = tx_buffer.enqueue_slice(data); (size, size) }) } fn recv_error_check(&mut self) -> Result<(), RecvError> { // We may have received some data inside the initial SYN, but until the connection // is fully open we must not dequeue any data, as it may be overwritten by e.g. // another (stale) SYN. (We do not support TCP Fast Open.) if !self.may_recv() { if self.rx_fin_received { return Err(RecvError::Finished); } return Err(RecvError::InvalidState); } Ok(()) } fn recv_impl<'b, F, R>(&'b mut self, f: F) -> Result where F: FnOnce(&'b mut SocketBuffer<'a>) -> (usize, R), { self.recv_error_check()?; let _old_length = self.rx_buffer.len(); let (size, result) = f(&mut self.rx_buffer); self.remote_seq_no += size; if size > 0 { #[cfg(any(test, feature = "verbose"))] tcp_trace!( "rx buffer: dequeueing {} octets (now {})", size, _old_length - size ); } Ok(result) } /// Call `f` with the largest contiguous slice of octets in the receive buffer, /// and dequeue the amount of elements returned by `f`. /// /// This function errors if the receive half of the connection is not open. /// /// If the receive half has been gracefully closed (with a FIN packet), `Err(Error::Finished)` /// is returned. In this case, the previously received data is guaranteed to be complete. /// /// In all other cases, `Err(Error::Illegal)` is returned and previously received data (if any) /// may be incomplete (truncated). pub fn recv<'b, F, R>(&'b mut self, f: F) -> Result where F: FnOnce(&'b mut [u8]) -> (usize, R), { self.recv_impl(|rx_buffer| rx_buffer.dequeue_many_with(f)) } /// Dequeue a sequence of received octets, and fill a slice from it. /// /// This function returns the amount of octets actually dequeued, which is limited /// by the amount of occupied space in the receive buffer; down to zero. /// /// See also [recv](#method.recv). pub fn recv_slice(&mut self, data: &mut [u8]) -> Result { self.recv_impl(|rx_buffer| { let size = rx_buffer.dequeue_slice(data); (size, size) }) } /// Peek at a sequence of received octets without removing them from /// the receive buffer, and return a pointer to it. /// /// This function otherwise behaves identically to [recv](#method.recv). pub fn peek(&mut self, size: usize) -> Result<&[u8], RecvError> { self.recv_error_check()?; let buffer = self.rx_buffer.get_allocated(0, size); if !buffer.is_empty() { #[cfg(any(test, feature = "verbose"))] tcp_trace!("rx buffer: peeking at {} octets", buffer.len()); } Ok(buffer) } /// Peek at a sequence of received octets without removing them from /// the receive buffer, and fill a slice from it. /// /// This function otherwise behaves identically to [recv_slice](#method.recv_slice). pub fn peek_slice(&mut self, data: &mut [u8]) -> Result { let buffer = self.peek(data.len())?; let data = &mut data[..buffer.len()]; data.copy_from_slice(buffer); Ok(buffer.len()) } /// Return the amount of octets queued in the transmit buffer. /// /// Note that the Berkeley sockets interface does not have an equivalent of this API. pub fn send_queue(&self) -> usize { self.tx_buffer.len() } /// Return the amount of octets queued in the receive buffer. This value can be larger than /// the slice read by the next `recv` or `peek` call because it includes all queued octets, /// and not only the octets that may be returned as a contiguous slice. /// /// Note that the Berkeley sockets interface does not have an equivalent of this API. pub fn recv_queue(&self) -> usize { self.rx_buffer.len() } fn set_state(&mut self, state: State) { if self.state != state { tcp_trace!("state={}=>{}", self.state, state); } self.state = state; #[cfg(feature = "async")] { // Wake all tasks waiting. Even if we haven't received/sent data, this // is needed because return values of functions may change depending on the state. // For example, a pending read has to fail with an error if the socket is closed. self.rx_waker.wake(); self.tx_waker.wake(); } } pub(crate) fn reply(ip_repr: &IpRepr, repr: &TcpRepr) -> (IpRepr, TcpRepr<'static>) { let reply_repr = TcpRepr { src_port: repr.dst_port, dst_port: repr.src_port, control: TcpControl::None, seq_number: TcpSeqNumber(0), ack_number: None, window_len: 0, window_scale: None, max_seg_size: None, sack_permitted: false, sack_ranges: [None, None, None], payload: &[], }; let ip_reply_repr = IpRepr::new( ip_repr.dst_addr(), ip_repr.src_addr(), IpProtocol::Tcp, reply_repr.buffer_len(), 64, ); (ip_reply_repr, reply_repr) } pub(crate) fn rst_reply(ip_repr: &IpRepr, repr: &TcpRepr) -> (IpRepr, TcpRepr<'static>) { debug_assert!(repr.control != TcpControl::Rst); let (ip_reply_repr, mut reply_repr) = Self::reply(ip_repr, repr); // See https://www.snellman.net/blog/archive/2016-02-01-tcp-rst/ for explanation // of why we sometimes send an RST and sometimes an RST|ACK reply_repr.control = TcpControl::Rst; reply_repr.seq_number = repr.ack_number.unwrap_or_default(); if repr.control == TcpControl::Syn && repr.ack_number.is_none() { reply_repr.ack_number = Some(repr.seq_number + repr.segment_len()); } (ip_reply_repr, reply_repr) } fn ack_reply(&mut self, ip_repr: &IpRepr, repr: &TcpRepr) -> (IpRepr, TcpRepr<'static>) { let (mut ip_reply_repr, mut reply_repr) = Self::reply(ip_repr, repr); // From RFC 793: // [...] an empty acknowledgment segment containing the current send-sequence number // and an acknowledgment indicating the next sequence number expected // to be received. reply_repr.seq_number = self.remote_last_seq; reply_repr.ack_number = Some(self.remote_seq_no + self.rx_buffer.len()); self.remote_last_ack = reply_repr.ack_number; // From RFC 1323: // The window field [...] of every outgoing segment, with the exception of SYN // segments, is right-shifted by [advertised scale value] bits[...] reply_repr.window_len = self.scaled_window(); self.remote_last_win = reply_repr.window_len; // If the remote supports selective acknowledgement, add the option to the outgoing // segment. if self.remote_has_sack { net_debug!("sending sACK option with current assembler ranges"); // RFC 2018: The first SACK block (i.e., the one immediately following the kind and // length fields in the option) MUST specify the contiguous block of data containing // the segment which triggered this ACK, unless that segment advanced the // Acknowledgment Number field in the header. reply_repr.sack_ranges[0] = None; if let Some(last_seg_seq) = self.local_rx_last_seq.map(|s| s.0 as u32) { reply_repr.sack_ranges[0] = self .assembler .iter_data(reply_repr.ack_number.map(|s| s.0 as usize).unwrap_or(0)) .map(|(left, right)| (left as u32, right as u32)) .find(|(left, right)| *left <= last_seg_seq && *right >= last_seg_seq); } if reply_repr.sack_ranges[0].is_none() { // The matching segment was removed from the assembler, meaning the acknowledgement // number has advanced, or there was no previous sACK. // // While the RFC says we SHOULD keep a list of reported sACK ranges, and iterate // through those, that is currently infeasible. Instead, we offer the range with // the lowest sequence number (if one exists) to hint at what segments would // most quickly advance the acknowledgement number. reply_repr.sack_ranges[0] = self .assembler .iter_data(reply_repr.ack_number.map(|s| s.0 as usize).unwrap_or(0)) .map(|(left, right)| (left as u32, right as u32)) .next(); } } // Since the sACK option may have changed the length of the payload, update that. ip_reply_repr.set_payload_len(reply_repr.buffer_len()); (ip_reply_repr, reply_repr) } fn challenge_ack_reply( &mut self, cx: &mut Context, ip_repr: &IpRepr, repr: &TcpRepr, ) -> Option<(IpRepr, TcpRepr<'static>)> { if cx.now() < self.challenge_ack_timer { return None; } // Rate-limit to 1 per second max. self.challenge_ack_timer = cx.now() + Duration::from_secs(1); return Some(self.ack_reply(ip_repr, repr)); } pub(crate) fn accepts(&self, _cx: &mut Context, ip_repr: &IpRepr, repr: &TcpRepr) -> bool { if self.state == State::Closed { return false; } // If we're still listening for SYNs and the packet has an ACK, it cannot // be destined to this socket, but another one may well listen on the same // local endpoint. if self.state == State::Listen && repr.ack_number.is_some() { return false; } if let Some(tuple) = &self.tuple { // Reject packets not matching the 4-tuple ip_repr.dst_addr() == tuple.local.addr && repr.dst_port == tuple.local.port && ip_repr.src_addr() == tuple.remote.addr && repr.src_port == tuple.remote.port } else { // We're listening, reject packets not matching the listen endpoint. let addr_ok = match self.listen_endpoint.addr { Some(addr) => ip_repr.dst_addr() == addr, None => true, }; addr_ok && repr.dst_port != 0 && repr.dst_port == self.listen_endpoint.port } } pub(crate) fn process( &mut self, cx: &mut Context, ip_repr: &IpRepr, repr: &TcpRepr, ) -> Option<(IpRepr, TcpRepr<'static>)> { debug_assert!(self.accepts(cx, ip_repr, repr)); // Consider how much the sequence number space differs from the transmit buffer space. let (sent_syn, sent_fin) = match self.state { // In SYN-SENT or SYN-RECEIVED, we've just sent a SYN. State::SynSent | State::SynReceived => (true, false), // In FIN-WAIT-1, LAST-ACK, or CLOSING, we've just sent a FIN. State::FinWait1 | State::LastAck | State::Closing => (false, true), // In all other states we've already got acknowledgements for // all of the control flags we sent. _ => (false, false), }; let control_len = (sent_syn as usize) + (sent_fin as usize); // Reject unacceptable acknowledgements. match (self.state, repr.control, repr.ack_number) { // An RST received in response to initial SYN is acceptable if it acknowledges // the initial SYN. (State::SynSent, TcpControl::Rst, None) => { net_debug!("unacceptable RST (expecting RST|ACK) in response to initial SYN"); return None; } (State::SynSent, TcpControl::Rst, Some(ack_number)) => { if ack_number != self.local_seq_no + 1 { net_debug!("unacceptable RST|ACK in response to initial SYN"); return None; } } // Any other RST need only have a valid sequence number. (_, TcpControl::Rst, _) => (), // The initial SYN cannot contain an acknowledgement. (State::Listen, _, None) => (), // This case is handled in `accepts()`. (State::Listen, _, Some(_)) => unreachable!(), // Every packet after the initial SYN must be an acknowledgement. (_, _, None) => { net_debug!("expecting an ACK"); return None; } // SYN|ACK in the SYN-SENT state must have the exact ACK number. (State::SynSent, TcpControl::Syn, Some(ack_number)) => { if ack_number != self.local_seq_no + 1 { net_debug!("unacceptable SYN|ACK in response to initial SYN"); return Some(Self::rst_reply(ip_repr, repr)); } } // ACKs in the SYN-SENT state are invalid. (State::SynSent, TcpControl::None, Some(ack_number)) => { // If the sequence number matches, ignore it instead of RSTing. // I'm not sure why, I think it may be a workaround for broken TCP // servers, or a defense against reordering. Either way, if Linux // does it, we do too. if ack_number == self.local_seq_no + 1 { net_debug!( "expecting a SYN|ACK, received an ACK with the right ack_number, ignoring." ); return None; } net_debug!( "expecting a SYN|ACK, received an ACK with the wrong ack_number, sending RST." ); return Some(Self::rst_reply(ip_repr, repr)); } // Anything else in the SYN-SENT state is invalid. (State::SynSent, _, _) => { net_debug!("expecting a SYN|ACK"); return None; } // ACK in the SYN-RECEIVED state must have the exact ACK number, or we RST it. (State::SynReceived, _, Some(ack_number)) => { if ack_number != self.local_seq_no + 1 { net_debug!("unacceptable ACK in response to SYN|ACK"); return Some(Self::rst_reply(ip_repr, repr)); } } // Every acknowledgement must be for transmitted but unacknowledged data. (_, _, Some(ack_number)) => { let unacknowledged = self.tx_buffer.len() + control_len; // Acceptable ACK range (both inclusive) let mut ack_min = self.local_seq_no; let ack_max = self.local_seq_no + unacknowledged; // If we have sent a SYN, it MUST be acknowledged. if sent_syn { ack_min += 1; } if ack_number < ack_min { net_debug!( "duplicate ACK ({} not in {}...{})", ack_number, ack_min, ack_max ); return None; } if ack_number > ack_max { net_debug!( "unacceptable ACK ({} not in {}...{})", ack_number, ack_min, ack_max ); return self.challenge_ack_reply(cx, ip_repr, repr); } } } let window_start = self.remote_seq_no + self.rx_buffer.len(); let window_end = self.remote_seq_no + self.rx_buffer.capacity(); let segment_start = repr.seq_number; let segment_end = repr.seq_number + repr.segment_len(); let payload_offset; match self.state { // In LISTEN and SYN-SENT states, we have not yet synchronized with the remote end. State::Listen | State::SynSent => payload_offset = 0, // In all other states, segments must occupy a valid portion of the receive window. _ => { let mut segment_in_window = true; if window_start == window_end && segment_start != segment_end { net_debug!( "non-zero-length segment with zero receive window, will only send an ACK" ); segment_in_window = false; } if segment_start == segment_end && segment_end == window_start - 1 { net_debug!("received a keep-alive or window probe packet, will send an ACK"); segment_in_window = false; } else if !((window_start <= segment_start && segment_start <= window_end) && (window_start <= segment_end && segment_end <= window_end)) { net_debug!( "segment not in receive window ({}..{} not intersecting {}..{}), will send challenge ACK", segment_start, segment_end, window_start, window_end ); segment_in_window = false; } if segment_in_window { // We've checked that segment_start >= window_start above. payload_offset = segment_start - window_start; self.local_rx_last_seq = Some(repr.seq_number); } else { // If we're in the TIME-WAIT state, restart the TIME-WAIT timeout, since // the remote end may not have realized we've closed the connection. if self.state == State::TimeWait { self.timer.set_for_close(cx.now()); } return self.challenge_ack_reply(cx, ip_repr, repr); } } } // Compute the amount of acknowledged octets, removing the SYN and FIN bits // from the sequence space. let mut ack_len = 0; let mut ack_of_fin = false; let mut ack_all = false; if repr.control != TcpControl::Rst { if let Some(ack_number) = repr.ack_number { // Sequence number corresponding to the first byte in `tx_buffer`. // This normally equals `local_seq_no`, but is 1 higher if we have sent a SYN, // as the SYN occupies 1 sequence number "before" the data. let tx_buffer_start_seq = self.local_seq_no + (sent_syn as usize); if ack_number >= tx_buffer_start_seq { ack_len = ack_number - tx_buffer_start_seq; // We could've sent data before the FIN, so only remove FIN from the sequence // space if all of that data is acknowledged. if sent_fin && self.tx_buffer.len() + 1 == ack_len { ack_len -= 1; tcp_trace!("received ACK of FIN"); ack_of_fin = true; } ack_all = self.remote_last_seq == ack_number } self.rtte.on_ack(cx.now(), ack_number); } } // Disregard control flags we don't care about or shouldn't act on yet. let mut control = repr.control; control = control.quash_psh(); // If a FIN is received at the end of the current segment but the start of the segment // is not at the start of the receive window, disregard this FIN. if control == TcpControl::Fin && window_start != segment_start { control = TcpControl::None; } // Validate and update the state. match (self.state, control) { // RSTs are not accepted in the LISTEN state. (State::Listen, TcpControl::Rst) => return None, // RSTs in SYN-RECEIVED flip the socket back to the LISTEN state. (State::SynReceived, TcpControl::Rst) => { tcp_trace!("received RST"); self.tuple = None; self.set_state(State::Listen); return None; } // RSTs in any other state close the socket. (_, TcpControl::Rst) => { tcp_trace!("received RST"); self.set_state(State::Closed); self.tuple = None; return None; } // SYN packets in the LISTEN state change it to SYN-RECEIVED. (State::Listen, TcpControl::Syn) => { tcp_trace!("received SYN"); if let Some(max_seg_size) = repr.max_seg_size { if max_seg_size == 0 { tcp_trace!("received SYNACK with zero MSS, ignoring"); return None; } self.remote_mss = max_seg_size as usize } self.tuple = Some(Tuple { local: IpEndpoint::new(ip_repr.dst_addr(), repr.dst_port), remote: IpEndpoint::new(ip_repr.src_addr(), repr.src_port), }); self.local_seq_no = Self::random_seq_no(cx); self.remote_seq_no = repr.seq_number + 1; self.remote_last_seq = self.local_seq_no; self.remote_has_sack = repr.sack_permitted; self.remote_win_scale = repr.window_scale; // Remote doesn't support window scaling, don't do it. if self.remote_win_scale.is_none() { self.remote_win_shift = 0; } self.set_state(State::SynReceived); self.timer.set_for_idle(cx.now(), self.keep_alive); } // ACK packets in the SYN-RECEIVED state change it to ESTABLISHED. (State::SynReceived, TcpControl::None) => { self.set_state(State::Established); self.timer.set_for_idle(cx.now(), self.keep_alive); } // FIN packets in the SYN-RECEIVED state change it to CLOSE-WAIT. // It's not obvious from RFC 793 that this is permitted, but // 7th and 8th steps in the "SEGMENT ARRIVES" event describe this behavior. (State::SynReceived, TcpControl::Fin) => { self.remote_seq_no += 1; self.rx_fin_received = true; self.set_state(State::CloseWait); self.timer.set_for_idle(cx.now(), self.keep_alive); } // SYN|ACK packets in the SYN-SENT state change it to ESTABLISHED. (State::SynSent, TcpControl::Syn) => { tcp_trace!("received SYN|ACK"); if let Some(max_seg_size) = repr.max_seg_size { if max_seg_size == 0 { tcp_trace!("received SYNACK with zero MSS, ignoring"); return None; } self.remote_mss = max_seg_size as usize; } self.remote_seq_no = repr.seq_number + 1; self.remote_last_seq = self.local_seq_no + 1; self.remote_last_ack = Some(repr.seq_number); self.remote_win_scale = repr.window_scale; // Remote doesn't support window scaling, don't do it. if self.remote_win_scale.is_none() { self.remote_win_shift = 0; } self.set_state(State::Established); self.timer.set_for_idle(cx.now(), self.keep_alive); } // ACK packets in ESTABLISHED state reset the retransmit timer, // except for duplicate ACK packets which preserve it. (State::Established, TcpControl::None) => { if !self.timer.is_retransmit() || ack_all { self.timer.set_for_idle(cx.now(), self.keep_alive); } } // FIN packets in ESTABLISHED state indicate the remote side has closed. (State::Established, TcpControl::Fin) => { self.remote_seq_no += 1; self.rx_fin_received = true; self.set_state(State::CloseWait); self.timer.set_for_idle(cx.now(), self.keep_alive); } // ACK packets in FIN-WAIT-1 state change it to FIN-WAIT-2, if we've already // sent everything in the transmit buffer. If not, they reset the retransmit timer. (State::FinWait1, TcpControl::None) => { if ack_of_fin { self.set_state(State::FinWait2); } if ack_all { self.timer.set_for_idle(cx.now(), self.keep_alive); } } // FIN packets in FIN-WAIT-1 state change it to CLOSING, or to TIME-WAIT // if they also acknowledge our FIN. (State::FinWait1, TcpControl::Fin) => { self.remote_seq_no += 1; self.rx_fin_received = true; if ack_of_fin { self.set_state(State::TimeWait); self.timer.set_for_close(cx.now()); } else { self.set_state(State::Closing); self.timer.set_for_idle(cx.now(), self.keep_alive); } } // Data packets in FIN-WAIT-2 reset the idle timer. (State::FinWait2, TcpControl::None) => { self.timer.set_for_idle(cx.now(), self.keep_alive); } // FIN packets in FIN-WAIT-2 state change it to TIME-WAIT. (State::FinWait2, TcpControl::Fin) => { self.remote_seq_no += 1; self.rx_fin_received = true; self.set_state(State::TimeWait); self.timer.set_for_close(cx.now()); } // ACK packets in CLOSING state change it to TIME-WAIT. (State::Closing, TcpControl::None) => { if ack_of_fin { self.set_state(State::TimeWait); self.timer.set_for_close(cx.now()); } else { self.timer.set_for_idle(cx.now(), self.keep_alive); } } // ACK packets in CLOSE-WAIT state reset the retransmit timer. (State::CloseWait, TcpControl::None) => { self.timer.set_for_idle(cx.now(), self.keep_alive); } // ACK packets in LAST-ACK state change it to CLOSED. (State::LastAck, TcpControl::None) => { if ack_of_fin { // Clear the remote endpoint, or we'll send an RST there. self.set_state(State::Closed); self.tuple = None; } else { self.timer.set_for_idle(cx.now(), self.keep_alive); } } _ => { net_debug!("unexpected packet {}", repr); return None; } } // Update remote state. self.remote_last_ts = Some(cx.now()); // RFC 1323: The window field (SEG.WND) in the header of every incoming segment, with the // exception of SYN segments, is left-shifted by Snd.Wind.Scale bits before updating SND.WND. let scale = match repr.control { TcpControl::Syn => 0, _ => self.remote_win_scale.unwrap_or(0), }; self.remote_win_len = (repr.window_len as usize) << (scale as usize); if ack_len > 0 { // Dequeue acknowledged octets. debug_assert!(self.tx_buffer.len() >= ack_len); tcp_trace!( "tx buffer: dequeueing {} octets (now {})", ack_len, self.tx_buffer.len() - ack_len ); self.tx_buffer.dequeue_allocated(ack_len); // There's new room available in tx_buffer, wake the waiting task if any. #[cfg(feature = "async")] self.tx_waker.wake(); } if let Some(ack_number) = repr.ack_number { // TODO: When flow control is implemented, // refractor the following block within that implementation // Detect and react to duplicate ACKs by: // 1. Check if duplicate ACK and change self.local_rx_dup_acks accordingly // 2. If exactly 3 duplicate ACKs received, set for fast retransmit // 3. Update the last received ACK (self.local_rx_last_ack) match self.local_rx_last_ack { // Duplicate ACK if payload empty and ACK doesn't move send window -> // Increment duplicate ACK count and set for retransmit if we just received // the third duplicate ACK Some(last_rx_ack) if repr.payload.is_empty() && last_rx_ack == ack_number && ack_number < self.remote_last_seq => { // Increment duplicate ACK count self.local_rx_dup_acks = self.local_rx_dup_acks.saturating_add(1); net_debug!( "received duplicate ACK for seq {} (duplicate nr {}{})", ack_number, self.local_rx_dup_acks, if self.local_rx_dup_acks == u8::max_value() { "+" } else { "" } ); if self.local_rx_dup_acks == 3 { self.timer.set_for_fast_retransmit(); net_debug!("started fast retransmit"); } } // No duplicate ACK -> Reset state and update last received ACK _ => { if self.local_rx_dup_acks > 0 { self.local_rx_dup_acks = 0; net_debug!("reset duplicate ACK count"); } self.local_rx_last_ack = Some(ack_number); } }; // We've processed everything in the incoming segment, so advance the local // sequence number past it. self.local_seq_no = ack_number; // During retransmission, if an earlier segment got lost but later was // successfully received, self.local_seq_no can move past self.remote_last_seq. // Do not attempt to retransmit the latter segments; not only this is pointless // in theory but also impossible in practice, since they have been already // deallocated from the buffer. if self.remote_last_seq < self.local_seq_no { self.remote_last_seq = self.local_seq_no } } let payload_len = repr.payload.len(); if payload_len == 0 { return None; } let assembler_was_empty = self.assembler.is_empty(); // Try adding payload octets to the assembler. let Ok(contig_len) = self.assembler.add_then_remove_front(payload_offset, payload_len) else { net_debug!( "assembler: too many holes to add {} octets at offset {}", payload_len, payload_offset ); return None; }; // Place payload octets into the buffer. tcp_trace!( "rx buffer: receiving {} octets at offset {}", payload_len, payload_offset ); let len_written = self .rx_buffer .write_unallocated(payload_offset, repr.payload); debug_assert!(len_written == payload_len); if contig_len != 0 { // Enqueue the contiguous data octets in front of the buffer. tcp_trace!( "rx buffer: enqueueing {} octets (now {})", contig_len, self.rx_buffer.len() + contig_len ); self.rx_buffer.enqueue_unallocated(contig_len); // There's new data in rx_buffer, notify waiting task if any. #[cfg(feature = "async")] self.rx_waker.wake(); } if !self.assembler.is_empty() { // Print the ranges recorded in the assembler. tcp_trace!("assembler: {}", self.assembler); } // Handle delayed acks if let Some(ack_delay) = self.ack_delay { if self.ack_to_transmit() || self.window_to_update() { self.ack_delay_timer = match self.ack_delay_timer { AckDelayTimer::Idle => { tcp_trace!("starting delayed ack timer"); AckDelayTimer::Waiting(cx.now() + ack_delay) } // RFC1122 says "in a stream of full-sized segments there SHOULD be an ACK // for at least every second segment". // For now, we send an ACK every second received packet, full-sized or not. AckDelayTimer::Waiting(_) => { tcp_trace!("delayed ack timer already started, forcing expiry"); AckDelayTimer::Immediate } AckDelayTimer::Immediate => { tcp_trace!("delayed ack timer already force-expired"); AckDelayTimer::Immediate } }; } } // Per RFC 5681, we should send an immediate ACK when either: // 1) an out-of-order segment is received, or // 2) a segment arrives that fills in all or part of a gap in sequence space. if !self.assembler.is_empty() || !assembler_was_empty { // Note that we change the transmitter state here. // This is fine because smoltcp assumes that it can always transmit zero or one // packets for every packet it receives. tcp_trace!("ACKing incoming segment"); Some(self.ack_reply(ip_repr, repr)) } else { None } } fn timed_out(&self, timestamp: Instant) -> bool { match (self.remote_last_ts, self.timeout) { (Some(remote_last_ts), Some(timeout)) => timestamp >= remote_last_ts + timeout, (_, _) => false, } } fn seq_to_transmit(&self, cx: &mut Context) -> bool { let ip_header_len = match self.tuple.unwrap().local.addr { #[cfg(feature = "proto-ipv4")] IpAddress::Ipv4(_) => crate::wire::IPV4_HEADER_LEN, #[cfg(feature = "proto-ipv6")] IpAddress::Ipv6(_) => crate::wire::IPV6_HEADER_LEN, }; // Max segment size we're able to send due to MTU limitations. let local_mss = cx.ip_mtu() - ip_header_len - TCP_HEADER_LEN; // The effective max segment size, taking into account our and remote's limits. let effective_mss = local_mss.min(self.remote_mss); // Have we sent data that hasn't been ACKed yet? let data_in_flight = self.remote_last_seq != self.local_seq_no; // If we want to send a SYN and we haven't done so, do it! if matches!(self.state, State::SynSent | State::SynReceived) && !data_in_flight { return true; } // max sequence number we can send. let max_send_seq = self.local_seq_no + core::cmp::min(self.remote_win_len, self.tx_buffer.len()); // Max amount of octets we can send. let max_send = if max_send_seq >= self.remote_last_seq { max_send_seq - self.remote_last_seq } else { 0 }; // Can we send at least 1 octet? let mut can_send = max_send != 0; // Can we send at least 1 full segment? let can_send_full = max_send >= effective_mss; // Do we have to send a FIN? let want_fin = match self.state { State::FinWait1 => true, State::Closing => true, State::LastAck => true, _ => false, }; // If we're applying the Nagle algorithm we don't want to send more // until one of: // * There's no data in flight // * We can send a full packet // * We have all the data we'll ever send (we're closing send) if self.nagle && data_in_flight && !can_send_full && !want_fin { can_send = false; } // Can we actually send the FIN? We can send it if: // 1. We have unsent data that fits in the remote window. // 2. We have no unsent data. // This condition matches only if #2, because #1 is already covered by can_data and we're ORing them. let can_fin = want_fin && self.remote_last_seq == self.local_seq_no + self.tx_buffer.len(); can_send || can_fin } fn delayed_ack_expired(&self, timestamp: Instant) -> bool { match self.ack_delay_timer { AckDelayTimer::Idle => true, AckDelayTimer::Waiting(t) => t <= timestamp, AckDelayTimer::Immediate => true, } } fn ack_to_transmit(&self) -> bool { if let Some(remote_last_ack) = self.remote_last_ack { remote_last_ack < self.remote_seq_no + self.rx_buffer.len() } else { false } } fn window_to_update(&self) -> bool { match self.state { State::SynSent | State::SynReceived | State::Established | State::FinWait1 | State::FinWait2 => self.scaled_window() > self.remote_last_win, _ => false, } } pub(crate) fn dispatch(&mut self, cx: &mut Context, emit: F) -> Result<(), E> where F: FnOnce(&mut Context, (IpRepr, TcpRepr)) -> Result<(), E>, { if self.tuple.is_none() { return Ok(()); } if self.remote_last_ts.is_none() { // We get here in exactly two cases: // 1) This socket just transitioned into SYN-SENT. // 2) This socket had an empty transmit buffer and some data was added there. // Both are similar in that the socket has been quiet for an indefinite // period of time, it isn't anymore, and the local endpoint is talking. // So, we start counting the timeout not from the last received packet // but from the first transmitted one. self.remote_last_ts = Some(cx.now()); } // Check if any state needs to be changed because of a timer. if self.timed_out(cx.now()) { // If a timeout expires, we should abort the connection. net_debug!("timeout exceeded"); self.set_state(State::Closed); } else if !self.seq_to_transmit(cx) { if let Some(retransmit_delta) = self.timer.should_retransmit(cx.now()) { // If a retransmit timer expired, we should resend data starting at the last ACK. net_debug!("retransmitting at t+{}", retransmit_delta); // Rewind "last sequence number sent", as if we never // had sent them. This will cause all data in the queue // to be sent again. self.remote_last_seq = self.local_seq_no; // Clear the `should_retransmit` state. If we can't retransmit right // now for whatever reason (like zero window), this avoids an // infinite polling loop where `poll_at` returns `Now` but `dispatch` // can't actually do anything. self.timer.set_for_idle(cx.now(), self.keep_alive); // Inform RTTE, so that it can avoid bogus measurements. self.rtte.on_retransmit(); } } // Decide whether we're sending a packet. if self.seq_to_transmit(cx) { // If we have data to transmit and it fits into partner's window, do it. tcp_trace!("outgoing segment will send data or flags"); } else if self.ack_to_transmit() && self.delayed_ack_expired(cx.now()) { // If we have data to acknowledge, do it. tcp_trace!("outgoing segment will acknowledge"); } else if self.window_to_update() && self.delayed_ack_expired(cx.now()) { // If we have window length increase to advertise, do it. tcp_trace!("outgoing segment will update window"); } else if self.state == State::Closed { // If we need to abort the connection, do it. tcp_trace!("outgoing segment will abort connection"); } else if self.timer.should_keep_alive(cx.now()) { // If we need to transmit a keep-alive packet, do it. tcp_trace!("keep-alive timer expired"); } else if self.timer.should_close(cx.now()) { // If we have spent enough time in the TIME-WAIT state, close the socket. tcp_trace!("TIME-WAIT timer expired"); self.reset(); return Ok(()); } else { return Ok(()); } // NOTE(unwrap): we check tuple is not None the first thing in this function. let tuple = self.tuple.unwrap(); // Construct the lowered IP representation. // We might need this to calculate the MSS, so do it early. let mut ip_repr = IpRepr::new( tuple.local.addr, tuple.remote.addr, IpProtocol::Tcp, 0, self.hop_limit.unwrap_or(64), ); // Construct the basic TCP representation, an empty ACK packet. // We'll adjust this to be more specific as needed. let mut repr = TcpRepr { src_port: tuple.local.port, dst_port: tuple.remote.port, control: TcpControl::None, seq_number: self.remote_last_seq, ack_number: Some(self.remote_seq_no + self.rx_buffer.len()), window_len: self.scaled_window(), window_scale: None, max_seg_size: None, sack_permitted: false, sack_ranges: [None, None, None], payload: &[], }; match self.state { // We transmit an RST in the CLOSED state. If we ended up in the CLOSED state // with a specified endpoint, it means that the socket was aborted. State::Closed => { repr.control = TcpControl::Rst; } // We never transmit anything in the LISTEN state. State::Listen => return Ok(()), // We transmit a SYN in the SYN-SENT state. // We transmit a SYN|ACK in the SYN-RECEIVED state. State::SynSent | State::SynReceived => { repr.control = TcpControl::Syn; // window len must NOT be scaled in SYNs. repr.window_len = self.rx_buffer.window().min((1 << 16) - 1) as u16; if self.state == State::SynSent { repr.ack_number = None; repr.window_scale = Some(self.remote_win_shift); repr.sack_permitted = true; } else { repr.sack_permitted = self.remote_has_sack; repr.window_scale = self.remote_win_scale.map(|_| self.remote_win_shift); } } // We transmit data in all states where we may have data in the buffer, // or the transmit half of the connection is still open. State::Established | State::FinWait1 | State::Closing | State::CloseWait | State::LastAck => { // Extract as much data as the remote side can receive in this packet // from the transmit buffer. // Right edge of window, ie the max sequence number we're allowed to send. let win_right_edge = self.local_seq_no + self.remote_win_len; // Max amount of octets we're allowed to send according to the remote window. let win_limit = if win_right_edge >= self.remote_last_seq { win_right_edge - self.remote_last_seq } else { // This can happen if we've sent some data and later the remote side // has shrunk its window so that data is no longer inside the window. // This should be very rare and is strongly discouraged by the RFCs, // but it does happen in practice. // http://www.tcpipguide.com/free/t_TCPWindowManagementIssues.htm 0 }; // Maximum size we're allowed to send. This can be limited by 3 factors: // 1. remote window // 2. MSS the remote is willing to accept, probably determined by their MTU // 3. MSS we can send, determined by our MTU. let size = win_limit .min(self.remote_mss) .min(cx.ip_mtu() - ip_repr.header_len() - TCP_HEADER_LEN); let offset = self.remote_last_seq - self.local_seq_no; 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 // flags, depending on whether the transmit half of the connection is open. if offset + repr.payload.len() == self.tx_buffer.len() { match self.state { State::FinWait1 | State::LastAck | State::Closing => { repr.control = TcpControl::Fin } State::Established | State::CloseWait if !repr.payload.is_empty() => { repr.control = TcpControl::Psh } _ => (), } } } // In FIN-WAIT-2 and TIME-WAIT states we may only transmit ACKs for incoming data or FIN State::FinWait2 | State::TimeWait => {} } // There might be more than one reason to send a packet. E.g. the keep-alive timer // has expired, and we also have data in transmit buffer. Since any packet that occupies // sequence space will elicit an ACK, we only need to send an explicit packet if we // couldn't fill the sequence space with anything. let is_keep_alive; if self.timer.should_keep_alive(cx.now()) && repr.is_empty() { repr.seq_number = repr.seq_number - 1; repr.payload = b"\x00"; // RFC 1122 says we should do this is_keep_alive = true; } else { is_keep_alive = false; } // Trace a summary of what will be sent. if is_keep_alive { tcp_trace!("sending a keep-alive"); } else if !repr.payload.is_empty() { tcp_trace!( "tx buffer: sending {} octets at offset {}", repr.payload.len(), self.remote_last_seq - self.local_seq_no ); } if repr.control != TcpControl::None || repr.payload.is_empty() { let flags = match (repr.control, repr.ack_number) { (TcpControl::Syn, None) => "SYN", (TcpControl::Syn, Some(_)) => "SYN|ACK", (TcpControl::Fin, Some(_)) => "FIN|ACK", (TcpControl::Rst, Some(_)) => "RST|ACK", (TcpControl::Psh, Some(_)) => "PSH|ACK", (TcpControl::None, Some(_)) => "ACK", _ => "", }; tcp_trace!("sending {}", flags); } if repr.control == TcpControl::Syn { // Fill the MSS option. See RFC 6691 for an explanation of this calculation. let max_segment_size = cx.ip_mtu() - ip_repr.header_len() - TCP_HEADER_LEN; repr.max_seg_size = Some(max_segment_size as u16); } // Actually send the packet. If this succeeds, it means the packet is in // the device buffer, and its transmission is imminent. If not, we might have // a number of problems, e.g. we need neighbor discovery. // // Bailing out if the packet isn't placed in the device buffer allows us // to not waste time waiting for the retransmit timer on packets that we know // for sure will not be successfully transmitted. ip_repr.set_payload_len(repr.buffer_len()); emit(cx, (ip_repr, repr))?; // We've sent something, whether useful data or a keep-alive packet, so rewind // the keep-alive timer. self.timer.rewind_keep_alive(cx.now(), self.keep_alive); // Reset delayed-ack timer match self.ack_delay_timer { AckDelayTimer::Idle => {} AckDelayTimer::Waiting(_) => { tcp_trace!("stop delayed ack timer") } AckDelayTimer::Immediate => { tcp_trace!("stop delayed ack timer (was force-expired)") } } self.ack_delay_timer = AckDelayTimer::Idle; // Leave the rest of the state intact if sending a keep-alive packet, since those // carry a fake segment. if is_keep_alive { return Ok(()); } // We've sent a packet successfully, so we can update the internal state now. self.remote_last_seq = repr.seq_number + repr.segment_len(); self.remote_last_ack = repr.ack_number; self.remote_last_win = repr.window_len; if repr.segment_len() > 0 { self.rtte .on_send(cx.now(), repr.seq_number + repr.segment_len()); } if !self.seq_to_transmit(cx) && repr.segment_len() > 0 { // If we've transmitted all data we could (and there was something at all, // data or flag, to transmit, not just an ACK), wind up the retransmit timer. self.timer .set_for_retransmit(cx.now(), self.rtte.retransmission_timeout()); } if self.state == State::Closed { // When aborting a connection, forget about it after sending a single RST packet. self.tuple = None; } Ok(()) } #[allow(clippy::if_same_then_else)] pub(crate) fn poll_at(&self, cx: &mut Context) -> PollAt { // The logic here mirrors the beginning of dispatch() closely. if self.tuple.is_none() { // No one to talk to, nothing to transmit. PollAt::Ingress } else if self.remote_last_ts.is_none() { // Socket stopped being quiet recently, we need to acquire a timestamp. PollAt::Now } else if self.state == State::Closed { // Socket was aborted, we have an RST packet to transmit. PollAt::Now } else if self.seq_to_transmit(cx) { // We have a data or flag packet to transmit. PollAt::Now } else { let want_ack = self.ack_to_transmit() || self.window_to_update(); let delayed_ack_poll_at = match (want_ack, self.ack_delay_timer) { (false, _) => PollAt::Ingress, (true, AckDelayTimer::Idle) => PollAt::Now, (true, AckDelayTimer::Waiting(t)) => PollAt::Time(t), (true, AckDelayTimer::Immediate) => PollAt::Now, }; let timeout_poll_at = match (self.remote_last_ts, self.timeout) { // If we're transmitting or retransmitting data, we need to poll at the moment // when the timeout would expire. (Some(remote_last_ts), Some(timeout)) => PollAt::Time(remote_last_ts + timeout), // Otherwise we have no timeout. (_, _) => PollAt::Ingress, }; // We wait for the earliest of our timers to fire. *[self.timer.poll_at(), timeout_poll_at, delayed_ack_poll_at] .iter() .min() .unwrap_or(&PollAt::Ingress) } } } impl<'a> fmt::Write for Socket<'a> { fn write_str(&mut self, slice: &str) -> fmt::Result { let slice = slice.as_bytes(); if self.send_slice(slice) == Ok(slice.len()) { Ok(()) } else { Err(fmt::Error) } } } #[cfg(test)] mod test { use super::*; use crate::wire::IpRepr; use core::i32; use std::ops::{Deref, DerefMut}; use std::vec::Vec; // =========================================================================================// // Constants // =========================================================================================// const LOCAL_PORT: u16 = 80; const REMOTE_PORT: u16 = 49500; const LISTEN_END: IpListenEndpoint = IpListenEndpoint { addr: None, port: LOCAL_PORT, }; const LOCAL_END: IpEndpoint = IpEndpoint { addr: LOCAL_ADDR.into_address(), port: LOCAL_PORT, }; const REMOTE_END: IpEndpoint = IpEndpoint { addr: REMOTE_ADDR.into_address(), port: REMOTE_PORT, }; const TUPLE: Tuple = Tuple { local: LOCAL_END, remote: REMOTE_END, }; const LOCAL_SEQ: TcpSeqNumber = TcpSeqNumber(10000); const REMOTE_SEQ: TcpSeqNumber = TcpSeqNumber(-10001); cfg_if::cfg_if! { if #[cfg(feature = "proto-ipv4")] { use crate::wire::Ipv4Address as IpvXAddress; use crate::wire::Ipv4Repr as IpvXRepr; use IpRepr::Ipv4 as IpReprIpvX; const LOCAL_ADDR: IpvXAddress = IpvXAddress([192, 168, 1, 1]); const REMOTE_ADDR: IpvXAddress = IpvXAddress([192, 168, 1, 2]); const OTHER_ADDR: IpvXAddress = IpvXAddress([192, 168, 1, 3]); const BASE_MSS: u16 = 1460; } else { use crate::wire::Ipv6Address as IpvXAddress; use crate::wire::Ipv6Repr as IpvXRepr; use IpRepr::Ipv6 as IpReprIpvX; const LOCAL_ADDR: IpvXAddress = IpvXAddress([ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, ]); const REMOTE_ADDR: IpvXAddress = IpvXAddress([ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, ]); const OTHER_ADDR: IpvXAddress = IpvXAddress([ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, ]); const BASE_MSS: u16 = 1440; } } const SEND_IP_TEMPL: IpRepr = IpReprIpvX(IpvXRepr { src_addr: LOCAL_ADDR, dst_addr: REMOTE_ADDR, next_header: IpProtocol::Tcp, payload_len: 20, hop_limit: 64, }); const SEND_TEMPL: TcpRepr<'static> = TcpRepr { src_port: REMOTE_PORT, dst_port: LOCAL_PORT, control: TcpControl::None, seq_number: TcpSeqNumber(0), ack_number: Some(TcpSeqNumber(0)), window_len: 256, window_scale: None, max_seg_size: None, sack_permitted: false, sack_ranges: [None, None, None], payload: &[], }; const _RECV_IP_TEMPL: IpRepr = IpReprIpvX(IpvXRepr { src_addr: LOCAL_ADDR, dst_addr: REMOTE_ADDR, next_header: IpProtocol::Tcp, payload_len: 20, hop_limit: 64, }); const RECV_TEMPL: TcpRepr<'static> = TcpRepr { src_port: LOCAL_PORT, dst_port: REMOTE_PORT, control: TcpControl::None, seq_number: TcpSeqNumber(0), ack_number: Some(TcpSeqNumber(0)), window_len: 64, window_scale: None, max_seg_size: None, sack_permitted: false, sack_ranges: [None, None, None], payload: &[], }; // =========================================================================================// // Helper functions // =========================================================================================// struct TestSocket { socket: Socket<'static>, cx: Context, } impl Deref for TestSocket { type Target = Socket<'static>; fn deref(&self) -> &Self::Target { &self.socket } } impl DerefMut for TestSocket { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.socket } } fn send( socket: &mut TestSocket, timestamp: Instant, repr: &TcpRepr, ) -> Option> { socket.cx.set_now(timestamp); let ip_repr = IpReprIpvX(IpvXRepr { src_addr: REMOTE_ADDR, dst_addr: LOCAL_ADDR, next_header: IpProtocol::Tcp, payload_len: repr.buffer_len(), hop_limit: 64, }); net_trace!("send: {}", repr); assert!(socket.socket.accepts(&mut socket.cx, &ip_repr, repr)); match socket.socket.process(&mut socket.cx, &ip_repr, repr) { Some((_ip_repr, repr)) => { net_trace!("recv: {}", repr); Some(repr) } None => None, } } fn recv(socket: &mut TestSocket, timestamp: Instant, mut f: F) where F: FnMut(Result), { socket.cx.set_now(timestamp); let mut sent = 0; let result = socket .socket .dispatch(&mut socket.cx, |_, (ip_repr, tcp_repr)| { assert_eq!(ip_repr.next_header(), IpProtocol::Tcp); assert_eq!(ip_repr.src_addr(), LOCAL_ADDR.into()); assert_eq!(ip_repr.dst_addr(), REMOTE_ADDR.into()); assert_eq!(ip_repr.payload_len(), tcp_repr.buffer_len()); net_trace!("recv: {}", tcp_repr); sent += 1; Ok(f(Ok(tcp_repr))) }); match result { Ok(()) => assert_eq!(sent, 1, "Exactly one packet should be sent"), Err(e) => f(Err(e)), } } fn recv_nothing(socket: &mut TestSocket, timestamp: Instant) { socket.cx.set_now(timestamp); let result: Result<(), ()> = socket .socket .dispatch(&mut socket.cx, |_, (_ip_repr, _tcp_repr)| { panic!("Should not send a packet") }); assert_eq!(result, Ok(())) } macro_rules! send { ($socket:ident, $repr:expr) => (send!($socket, time 0, $repr)); ($socket:ident, $repr:expr, $result:expr) => (send!($socket, time 0, $repr, $result)); ($socket:ident, time $time:expr, $repr:expr) => (send!($socket, time $time, $repr, None)); ($socket:ident, time $time:expr, $repr:expr, $result:expr) => (assert_eq!(send(&mut $socket, Instant::from_millis($time), &$repr), $result)); } macro_rules! recv { ($socket:ident, [$( $repr:expr ),*]) => ({ $( recv!($socket, Ok($repr)); )* recv_nothing!($socket) }); ($socket:ident, $result:expr) => (recv!($socket, time 0, $result)); ($socket:ident, time $time:expr, $result:expr) => (recv(&mut $socket, Instant::from_millis($time), |result| { // Most of the time we don't care about the PSH flag. let result = result.map(|mut repr| { repr.control = repr.control.quash_psh(); repr }); assert_eq!(result, $result) })); ($socket:ident, time $time:expr, $result:expr, exact) => (recv(&mut $socket, Instant::from_millis($time), |repr| assert_eq!(repr, $result))); } macro_rules! recv_nothing { ($socket:ident) => (recv_nothing!($socket, time 0)); ($socket:ident, time $time:expr) => (recv_nothing(&mut $socket, Instant::from_millis($time))); } macro_rules! sanity { ($socket1:expr, $socket2:expr) => {{ let (s1, s2) = ($socket1, $socket2); assert_eq!(s1.state, s2.state, "state"); assert_eq!(s1.tuple, s2.tuple, "tuple"); assert_eq!(s1.local_seq_no, s2.local_seq_no, "local_seq_no"); assert_eq!(s1.remote_seq_no, s2.remote_seq_no, "remote_seq_no"); assert_eq!(s1.remote_last_seq, s2.remote_last_seq, "remote_last_seq"); assert_eq!(s1.remote_last_ack, s2.remote_last_ack, "remote_last_ack"); assert_eq!(s1.remote_last_win, s2.remote_last_win, "remote_last_win"); assert_eq!(s1.remote_win_len, s2.remote_win_len, "remote_win_len"); assert_eq!(s1.timer, s2.timer, "timer"); }}; } fn socket() -> TestSocket { socket_with_buffer_sizes(64, 64) } fn socket_with_buffer_sizes(tx_len: usize, rx_len: usize) -> TestSocket { let rx_buffer = SocketBuffer::new(vec![0; rx_len]); let tx_buffer = SocketBuffer::new(vec![0; tx_len]); let mut socket = Socket::new(rx_buffer, tx_buffer); socket.set_ack_delay(None); let cx = Context::mock(); TestSocket { socket, cx } } fn socket_syn_received_with_buffer_sizes(tx_len: usize, rx_len: usize) -> TestSocket { let mut s = socket_with_buffer_sizes(tx_len, rx_len); s.state = State::SynReceived; s.tuple = Some(TUPLE); s.local_seq_no = LOCAL_SEQ; s.remote_seq_no = REMOTE_SEQ + 1; s.remote_last_seq = LOCAL_SEQ; s.remote_win_len = 256; s } fn socket_syn_received() -> TestSocket { socket_syn_received_with_buffer_sizes(64, 64) } fn socket_syn_sent_with_buffer_sizes(tx_len: usize, rx_len: usize) -> TestSocket { let mut s = socket_with_buffer_sizes(tx_len, rx_len); s.state = State::SynSent; s.tuple = Some(TUPLE); s.local_seq_no = LOCAL_SEQ; s.remote_last_seq = LOCAL_SEQ; s } fn socket_syn_sent() -> TestSocket { socket_syn_sent_with_buffer_sizes(64, 64) } fn socket_established_with_buffer_sizes(tx_len: usize, rx_len: usize) -> TestSocket { let mut s = socket_syn_received_with_buffer_sizes(tx_len, rx_len); s.state = State::Established; s.local_seq_no = LOCAL_SEQ + 1; s.remote_last_seq = LOCAL_SEQ + 1; s.remote_last_ack = Some(REMOTE_SEQ + 1); s.remote_last_win = 64; s } fn socket_established() -> TestSocket { socket_established_with_buffer_sizes(64, 64) } fn socket_fin_wait_1() -> TestSocket { let mut s = socket_established(); s.state = State::FinWait1; s } fn socket_fin_wait_2() -> TestSocket { let mut s = socket_fin_wait_1(); s.state = State::FinWait2; s.local_seq_no = LOCAL_SEQ + 1 + 1; s.remote_last_seq = LOCAL_SEQ + 1 + 1; s } fn socket_closing() -> TestSocket { let mut s = socket_fin_wait_1(); s.state = State::Closing; s.remote_last_seq = LOCAL_SEQ + 1 + 1; s.remote_seq_no = REMOTE_SEQ + 1 + 1; s } fn socket_time_wait(from_closing: bool) -> TestSocket { let mut s = socket_fin_wait_2(); s.state = State::TimeWait; s.remote_seq_no = REMOTE_SEQ + 1 + 1; if from_closing { s.remote_last_ack = Some(REMOTE_SEQ + 1 + 1); } s.timer = Timer::Close { expires_at: Instant::from_secs(1) + CLOSE_DELAY, }; s } fn socket_close_wait() -> TestSocket { let mut s = socket_established(); s.state = State::CloseWait; s.remote_seq_no = REMOTE_SEQ + 1 + 1; s.remote_last_ack = Some(REMOTE_SEQ + 1 + 1); s } fn socket_last_ack() -> TestSocket { let mut s = socket_close_wait(); s.state = State::LastAck; s } fn socket_recved() -> TestSocket { let mut s = socket_established(); 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), window_len: 58, ..RECV_TEMPL }] ); s } // =========================================================================================// // Tests for the CLOSED state. // =========================================================================================// #[test] fn test_closed_reject() { let mut s = socket(); assert_eq!(s.state, State::Closed); let tcp_repr = TcpRepr { control: TcpControl::Syn, ..SEND_TEMPL }; assert!(!s.socket.accepts(&mut s.cx, &SEND_IP_TEMPL, &tcp_repr)); } #[test] fn test_closed_reject_after_listen() { let mut s = socket(); s.listen(LOCAL_END).unwrap(); s.close(); let tcp_repr = TcpRepr { control: TcpControl::Syn, ..SEND_TEMPL }; assert!(!s.socket.accepts(&mut s.cx, &SEND_IP_TEMPL, &tcp_repr)); } #[test] fn test_closed_close() { let mut s = socket(); s.close(); assert_eq!(s.state, State::Closed); } // =========================================================================================// // Tests for the LISTEN state. // =========================================================================================// fn socket_listen() -> TestSocket { let mut s = socket(); s.state = State::Listen; s.listen_endpoint = LISTEN_END; s } #[test] fn test_listen_sack_option() { let mut s = socket_listen(); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: None, sack_permitted: false, ..SEND_TEMPL } ); assert!(!s.remote_has_sack); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL }] ); let mut s = socket_listen(); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: None, sack_permitted: true, ..SEND_TEMPL } ); assert!(s.remote_has_sack); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), sack_permitted: true, ..RECV_TEMPL }] ); } #[test] fn test_listen_syn_win_scale_buffers() { for (buffer_size, shift_amt) in &[ (64, 0), (128, 0), (1024, 0), (65535, 0), (65536, 1), (65537, 1), (131071, 1), (131072, 2), (524287, 3), (524288, 4), (655350, 4), (1048576, 5), ] { let mut s = socket_with_buffer_sizes(64, *buffer_size); s.state = State::Listen; s.listen_endpoint = LISTEN_END; assert_eq!(s.remote_win_shift, *shift_amt); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: None, window_scale: Some(0), ..SEND_TEMPL } ); assert_eq!(s.remote_win_shift, *shift_amt); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), window_scale: Some(*shift_amt), window_len: cmp::min(*buffer_size, 65535) as u16, ..RECV_TEMPL }] ); } } #[test] fn test_listen_sanity() { let mut s = socket(); s.listen(LOCAL_PORT).unwrap(); sanity!(s, socket_listen()); } #[test] fn test_listen_validation() { let mut s = socket(); assert_eq!(s.listen(0), Err(ListenError::Unaddressable)); } #[test] fn test_listen_twice() { let mut s = socket(); assert_eq!(s.listen(80), Ok(())); assert_eq!(s.listen(80), Err(ListenError::InvalidState)); } #[test] fn test_listen_syn() { let mut s = socket_listen(); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: None, ..SEND_TEMPL } ); sanity!(s, socket_syn_received()); } #[test] fn test_listen_syn_reject_ack() { let mut s = socket_listen(); let tcp_repr = TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ), ..SEND_TEMPL }; assert!(!s.socket.accepts(&mut s.cx, &SEND_IP_TEMPL, &tcp_repr)); assert_eq!(s.state, State::Listen); } #[test] fn test_listen_rst() { let mut s = socket_listen(); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ, ack_number: None, ..SEND_TEMPL } ); assert_eq!(s.state, State::Listen); } #[test] fn test_listen_close() { let mut s = socket_listen(); s.close(); assert_eq!(s.state, State::Closed); } // =========================================================================================// // Tests for the SYN-RECEIVED state. // =========================================================================================// #[test] fn test_syn_received_ack() { let mut s = socket_syn_received(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); assert_eq!(s.state, State::Established); sanity!(s, socket_established()); } #[test] fn test_syn_received_ack_too_low() { let mut s = socket_syn_received(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ), // wrong ..SEND_TEMPL }, Some(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ, ack_number: None, window_len: 0, ..RECV_TEMPL }) ); assert_eq!(s.state, State::SynReceived); } #[test] fn test_syn_received_ack_too_high() { let mut s = socket_syn_received(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 2), // wrong ..SEND_TEMPL }, Some(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 2, ack_number: None, window_len: 0, ..RECV_TEMPL }) ); assert_eq!(s.state, State::SynReceived); } #[test] fn test_syn_received_fin() { let mut s = socket_syn_received(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::Fin, 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 + 1), window_len: 58, ..RECV_TEMPL }] ); assert_eq!(s.state, State::CloseWait); let mut s2 = socket_close_wait(); s2.remote_last_ack = Some(REMOTE_SEQ + 1 + 6 + 1); s2.remote_last_win = 58; sanity!(s, s2); } #[test] fn test_syn_received_rst() { let mut s = socket_syn_received(); s.listen_endpoint = LISTEN_END; recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ), ..SEND_TEMPL } ); assert_eq!(s.state, State::Listen); assert_eq!(s.listen_endpoint, LISTEN_END); assert_eq!(s.tuple, None); } #[test] fn test_syn_received_no_window_scaling() { let mut s = socket_listen(); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: None, ..SEND_TEMPL } ); assert_eq!(s.state(), State::SynReceived); assert_eq!(s.tuple, Some(TUPLE)); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), window_scale: None, ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), window_scale: None, ..SEND_TEMPL } ); assert_eq!(s.remote_win_shift, 0); assert_eq!(s.remote_win_scale, None); } #[test] fn test_syn_received_window_scaling() { for scale in 0..14 { let mut s = socket_listen(); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: None, window_scale: Some(scale), ..SEND_TEMPL } ); assert_eq!(s.state(), State::SynReceived); assert_eq!(s.tuple, Some(TUPLE)); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), window_scale: Some(0), ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), window_scale: None, ..SEND_TEMPL } ); assert_eq!(s.remote_win_scale, Some(scale)); } } #[test] fn test_syn_received_close() { let mut s = socket_syn_received(); s.close(); assert_eq!(s.state, State::FinWait1); } // =========================================================================================// // Tests for the SYN-SENT state. // =========================================================================================// #[test] fn test_connect_validation() { let mut s = socket(); assert_eq!( s.socket .connect(&mut s.cx, REMOTE_END, (IpvXAddress::UNSPECIFIED, 0)), Err(ConnectError::Unaddressable) ); assert_eq!( s.socket .connect(&mut s.cx, REMOTE_END, (IpvXAddress::UNSPECIFIED, 1024)), Err(ConnectError::Unaddressable) ); assert_eq!( s.socket .connect(&mut s.cx, (IpvXAddress::UNSPECIFIED, 0), LOCAL_END), Err(ConnectError::Unaddressable) ); s.socket .connect(&mut s.cx, REMOTE_END, LOCAL_END) .expect("Connect failed with valid parameters"); assert_eq!(s.tuple, Some(TUPLE)); } #[test] fn test_connect() { let mut s = socket(); s.local_seq_no = LOCAL_SEQ; s.socket .connect(&mut s.cx, REMOTE_END, LOCAL_END.port) .unwrap(); assert_eq!(s.tuple, Some(TUPLE)); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(0), sack_permitted: true, ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ + 1), max_seg_size: Some(BASE_MSS - 80), window_scale: Some(0), ..SEND_TEMPL } ); assert_eq!(s.tuple, Some(TUPLE)); } #[test] fn test_connect_unspecified_local() { let mut s = socket(); assert_eq!(s.socket.connect(&mut s.cx, REMOTE_END, 80), Ok(())); } #[test] fn test_connect_specified_local() { let mut s = socket(); assert_eq!( s.socket.connect(&mut s.cx, REMOTE_END, (REMOTE_ADDR, 80)), Ok(()) ); } #[test] fn test_connect_twice() { let mut s = socket(); assert_eq!(s.socket.connect(&mut s.cx, REMOTE_END, 80), Ok(())); assert_eq!( s.socket.connect(&mut s.cx, REMOTE_END, 80), Err(ConnectError::InvalidState) ); } #[test] fn test_syn_sent_sanity() { let mut s = socket(); s.local_seq_no = LOCAL_SEQ; s.socket.connect(&mut s.cx, REMOTE_END, LOCAL_END).unwrap(); sanity!(s, socket_syn_sent()); } #[test] fn test_syn_sent_syn_ack() { let mut s = socket_syn_sent(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(0), sack_permitted: true, ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ + 1), max_seg_size: Some(BASE_MSS - 80), window_scale: Some(0), ..SEND_TEMPL } ); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }] ); recv_nothing!(s, time 1000); assert_eq!(s.state, State::Established); sanity!(s, socket_established()); } #[test] fn test_syn_sent_syn_ack_not_incremented() { let mut s = socket_syn_sent(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(0), sack_permitted: true, ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ), // WRONG max_seg_size: Some(BASE_MSS - 80), window_scale: Some(0), ..SEND_TEMPL }, Some(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ, ack_number: None, window_len: 0, ..RECV_TEMPL }) ); assert_eq!(s.state, State::SynSent); } #[test] fn test_syn_sent_rst() { let mut s = socket_syn_sent(); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); assert_eq!(s.state, State::Closed); } #[test] fn test_syn_sent_rst_no_ack() { let mut s = socket_syn_sent(); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ, ack_number: None, ..SEND_TEMPL } ); assert_eq!(s.state, State::SynSent); } #[test] fn test_syn_sent_rst_bad_ack() { let mut s = socket_syn_sent(); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ, ack_number: Some(TcpSeqNumber(1234)), ..SEND_TEMPL } ); assert_eq!(s.state, State::SynSent); } #[test] fn test_syn_sent_bad_ack() { let mut s = socket_syn_sent(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(0), sack_permitted: true, ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::None, // Unexpected seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ + 1), // Correct ..SEND_TEMPL } ); // It should trigger no response and change no state recv!(s, []); assert_eq!(s.state, State::SynSent); } #[test] fn test_syn_sent_bad_ack_seq_1() { let mut s = socket_syn_sent(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(0), sack_permitted: true, ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::None, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ), // WRONG ..SEND_TEMPL }, Some(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ, // matching the ack_number of the unexpected ack ack_number: None, window_len: 0, ..RECV_TEMPL }) ); // It should trigger a RST, and change no state assert_eq!(s.state, State::SynSent); } #[test] fn test_syn_sent_bad_ack_seq_2() { let mut s = socket_syn_sent(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(0), sack_permitted: true, ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::None, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ + 123456), // WRONG ..SEND_TEMPL }, Some(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 123456, // matching the ack_number of the unexpected ack ack_number: None, window_len: 0, ..RECV_TEMPL }) ); // It should trigger a RST, and change no state assert_eq!(s.state, State::SynSent); } #[test] fn test_syn_sent_close() { let mut s = socket(); s.close(); assert_eq!(s.state, State::Closed); } #[test] fn test_syn_sent_win_scale_buffers() { for (buffer_size, shift_amt) in &[ (64, 0), (128, 0), (1024, 0), (65535, 0), (65536, 1), (65537, 1), (131071, 1), (131072, 2), (524287, 3), (524288, 4), (655350, 4), (1048576, 5), ] { let mut s = socket_with_buffer_sizes(64, *buffer_size); s.local_seq_no = LOCAL_SEQ; assert_eq!(s.remote_win_shift, *shift_amt); s.socket.connect(&mut s.cx, REMOTE_END, LOCAL_END).unwrap(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(*shift_amt), window_len: cmp::min(*buffer_size, 65535) as u16, sack_permitted: true, ..RECV_TEMPL }] ); } } #[test] fn test_syn_sent_syn_ack_no_window_scaling() { let mut s = socket_syn_sent_with_buffer_sizes(1048576, 1048576); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), // scaling does NOT apply to the window value in SYN packets window_len: 65535, window_scale: Some(5), sack_permitted: true, ..RECV_TEMPL }] ); assert_eq!(s.remote_win_shift, 5); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ + 1), max_seg_size: Some(BASE_MSS - 80), window_scale: None, window_len: 42, ..SEND_TEMPL } ); assert_eq!(s.state, State::Established); assert_eq!(s.remote_win_shift, 0); assert_eq!(s.remote_win_scale, None); assert_eq!(s.remote_win_len, 42); } #[test] fn test_syn_sent_syn_ack_window_scaling() { let mut s = socket_syn_sent(); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(0), sack_permitted: true, ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ + 1), max_seg_size: Some(BASE_MSS - 80), window_scale: Some(7), window_len: 42, ..SEND_TEMPL } ); assert_eq!(s.state, State::Established); assert_eq!(s.remote_win_scale, Some(7)); // scaling does NOT apply to the window value in SYN packets assert_eq!(s.remote_win_len, 42); } // =========================================================================================// // Tests for the ESTABLISHED state. // =========================================================================================// #[test] fn test_established_recv() { let mut s = socket_established(); 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), window_len: 58, ..RECV_TEMPL }] ); assert_eq!(s.rx_buffer.dequeue_many(6), &b"abcdef"[..]); } fn setup_rfc2018_cases() -> (TestSocket, Vec) { // This is a utility function used by the tests for RFC 2018 cases. It configures a socket // in a particular way suitable for those cases. // // RFC 2018: Assume the left window edge is 5000 and that the data transmitter sends [...] // segments, each containing 500 data bytes. let mut s = socket_established_with_buffer_sizes(4000, 4000); s.remote_has_sack = true; // create a segment that is 500 bytes long let mut segment: Vec = Vec::with_capacity(500); // move the last ack to 5000 by sending ten of them for _ in 0..50 { segment.extend_from_slice(b"abcdefghij") } for offset in (0..5000).step_by(500) { send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + offset, ack_number: Some(LOCAL_SEQ + 1), payload: &segment, ..SEND_TEMPL } ); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + offset + 500), window_len: 3500, ..RECV_TEMPL }] ); s.recv(|data| { assert_eq!(data.len(), 500); assert_eq!(data, segment.as_slice()); (500, ()) }) .unwrap(); } assert_eq!(s.remote_last_win, 3500); (s, segment) } #[test] fn test_established_rfc2018_cases() { // This test case verifies the exact scenarios described on pages 8-9 of RFC 2018. Please // ensure its behavior does not deviate from those scenarios. let (mut s, segment) = setup_rfc2018_cases(); // RFC 2018: // // Case 2: The first segment is dropped but the remaining 7 are received. // // Upon receiving each of the last seven packets, the data receiver will return a TCP ACK // segment that acknowledges sequence number 5000 and contains a SACK option specifying one // block of queued data: // // Triggering ACK Left Edge Right Edge // Segment // // 5000 (lost) // 5500 5000 5500 6000 // 6000 5000 5500 6500 // 6500 5000 5500 7000 // 7000 5000 5500 7500 // 7500 5000 5500 8000 // 8000 5000 5500 8500 // 8500 5000 5500 9000 // for offset in (500..3500).step_by(500) { send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + offset + 5000, ack_number: Some(LOCAL_SEQ + 1), payload: &segment, ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 5000), window_len: 4000, sack_ranges: [ Some(( REMOTE_SEQ.0 as u32 + 1 + 5500, REMOTE_SEQ.0 as u32 + 1 + 5500 + offset as u32 )), None, None ], ..RECV_TEMPL }) ); } } #[test] fn test_established_sliding_window_recv() { let mut s = socket_established(); // Update our scaling parameters for a TCP with a scaled buffer. assert_eq!(s.rx_buffer.len(), 0); s.rx_buffer = SocketBuffer::new(vec![0; 262143]); s.assembler = Assembler::new(); s.remote_win_scale = Some(0); s.remote_last_win = 65535; s.remote_win_shift = 2; // Create a TCP segment that will mostly fill an IP frame. let mut segment: Vec = Vec::with_capacity(1400); for _ in 0..100 { segment.extend_from_slice(b"abcdefghijklmn") } assert_eq!(segment.len(), 1400); // Send the frame send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &segment, ..SEND_TEMPL } ); // Ensure that the received window size is shifted right by 2. recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1400), window_len: 65185, ..RECV_TEMPL }] ); } #[test] fn test_established_send() { let mut s = socket_established(); // First roundtrip after establishing. 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 }] ); assert_eq!(s.tx_buffer.len(), 6); 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.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 { 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.set_nagle_enabled(false); 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.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 }] ); } #[test] fn test_established_send_buf_gt_win() { let mut data = [0; 32]; for (i, elem) in data.iter_mut().enumerate() { *elem = i as u8 } let mut s = socket_established(); s.remote_win_len = 16; s.send_slice(&data[..]).unwrap(); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &data[0..16], ..RECV_TEMPL }] ); } #[test] fn test_established_send_window_shrink() { let mut s = socket_established(); // 6 octets fit on the remote side's window, so we send them. 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 }] ); assert_eq!(s.tx_buffer.len(), 6); println!( "local_seq_no={} remote_win_len={} remote_last_seq={}", s.local_seq_no, s.remote_win_len, s.remote_last_seq ); // - Peer doesn't ack them yet // - Sends data so we need to reply with an ACK // - ...AND and sends a window announcement that SHRINKS the window, so data we've // previously sent is now outside the window. Yes, this is allowed by TCP. send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), window_len: 3, payload: &b"xyzxyz"[..], ..SEND_TEMPL } ); assert_eq!(s.tx_buffer.len(), 6); println!( "local_seq_no={} remote_win_len={} remote_last_seq={}", s.local_seq_no, s.remote_win_len, s.remote_last_seq ); // More data should not get sent since it doesn't fit in the window s.send_slice(b"foobar").unwrap(); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1 + 6), window_len: 64 - 6, ..RECV_TEMPL }] ); } #[test] fn test_established_send_wrap() { let mut s = socket_established(); let local_seq_start = TcpSeqNumber(i32::MAX - 1); s.local_seq_no = local_seq_start + 1; s.remote_last_seq = local_seq_start + 1; s.send_slice(b"abc").unwrap(); recv!(s, time 1000, Ok(TcpRepr { seq_number: local_seq_start + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abc"[..], ..RECV_TEMPL })); } #[test] fn test_established_no_ack() { let mut s = socket_established(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: None, ..SEND_TEMPL } ); } #[test] fn test_established_bad_ack() { let mut s = socket_established(); // Already acknowledged data. send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(TcpSeqNumber(LOCAL_SEQ.0 - 1)), ..SEND_TEMPL } ); assert_eq!(s.local_seq_no, LOCAL_SEQ + 1); // Data not yet transmitted. send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 10), ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }) ); assert_eq!(s.local_seq_no, LOCAL_SEQ + 1); } #[test] fn test_established_bad_seq() { let mut s = socket_established(); // Data outside of receive window. send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 256, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }) ); assert_eq!(s.remote_seq_no, REMOTE_SEQ + 1); // Challenge ACKs are rate-limited, we don't get a second one immediately. send!( s, time 100, TcpRepr { seq_number: REMOTE_SEQ + 1 + 256, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); // If we wait a bit, we do get a new one. send!( s, time 2000, TcpRepr { seq_number: REMOTE_SEQ + 1 + 256, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }) ); assert_eq!(s.remote_seq_no, REMOTE_SEQ + 1); } #[test] fn test_established_fin() { let mut s = socket_established(); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL }] ); assert_eq!(s.state, State::CloseWait); sanity!(s, socket_close_wait()); } #[test] fn test_established_fin_after_missing() { let mut s = socket_established(); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1 + 6, ack_number: Some(LOCAL_SEQ + 1), payload: &b"123456"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }) ); assert_eq!(s.state, State::Established); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abcdef"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 6 + 6), window_len: 52, ..RECV_TEMPL }) ); assert_eq!(s.state, State::Established); } #[test] fn test_established_send_fin() { let mut s = socket_established(); 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, ack_number: Some(REMOTE_SEQ + 1 + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }] ); } #[test] fn test_established_rst() { let mut s = socket_established(); 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 { control: TcpControl::Rst, seq_number: REMOTE_SEQ + 1, ack_number: None, ..SEND_TEMPL } ); assert_eq!(s.state, State::Closed); } #[test] fn test_established_close() { let mut s = socket_established(); s.close(); assert_eq!(s.state, State::FinWait1); sanity!(s, socket_fin_wait_1()); } #[test] fn test_established_abort() { let mut s = socket_established(); s.abort(); assert_eq!(s.state, State::Closed); recv!( s, [TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }] ); } #[test] fn test_established_rst_bad_seq() { let mut s = socket_established(); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ, // Wrong seq ack_number: None, ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }) ); assert_eq!(s.state, State::Established); // Send something to advance seq by 1 send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, // correct seq ack_number: Some(LOCAL_SEQ + 1), payload: &b"a"[..], ..SEND_TEMPL } ); // Send wrong rst again, check that the challenge ack is correctly updated // The ack number must be updated even if we don't call dispatch on the socket // See https://github.com/smoltcp-rs/smoltcp/issues/338 send!( s, time 2000, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ, // Wrong seq ack_number: None, ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 2), // this has changed window_len: 63, ..RECV_TEMPL }) ); } // =========================================================================================// // Tests for the FIN-WAIT-1 state. // =========================================================================================// #[test] fn test_fin_wait_1_fin_ack() { let mut s = socket_fin_wait_1(); 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); sanity!(s, socket_fin_wait_2()); } #[test] fn test_fin_wait_1_fin_fin() { let mut s = socket_fin_wait_1(); recv!( s, [TcpRepr { 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); sanity!(s, socket_closing()); } #[test] fn test_fin_wait_1_fin_with_data_queued() { let mut s = socket_established(); s.remote_win_len = 6; s.send_slice(b"abcdef123456").unwrap(); s.close(); recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }) ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6), ..SEND_TEMPL } ); assert_eq!(s.state, State::FinWait1); } #[test] fn test_fin_wait_1_recv() { let mut s = socket_fin_wait_1(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); assert_eq!(s.state, State::FinWait1); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); } #[test] fn test_fin_wait_1_close() { let mut s = socket_fin_wait_1(); s.close(); assert_eq!(s.state, State::FinWait1); } // =========================================================================================// // Tests for the FIN-WAIT-2 state. // =========================================================================================// #[test] fn test_fin_wait_2_fin() { let mut s = socket_fin_wait_2(); send!(s, time 1_000, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 1), ..SEND_TEMPL }); assert_eq!(s.state, State::TimeWait); sanity!(s, socket_time_wait(false)); } #[test] fn test_fin_wait_2_recv() { let mut s = socket_fin_wait_2(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); assert_eq!(s.state, State::FinWait2); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1 + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), ..RECV_TEMPL }] ); } #[test] fn test_fin_wait_2_close() { let mut s = socket_fin_wait_2(); s.close(); assert_eq!(s.state, State::FinWait2); } // =========================================================================================// // Tests for the CLOSING state. // =========================================================================================// #[test] fn test_closing_ack_fin() { let mut s = socket_closing(); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1 + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL }] ); send!(s, time 1_000, TcpRepr { seq_number: REMOTE_SEQ + 1 + 1, ack_number: Some(LOCAL_SEQ + 1 + 1), ..SEND_TEMPL }); assert_eq!(s.state, State::TimeWait); sanity!(s, socket_time_wait(true)); } #[test] fn test_closing_close() { let mut s = socket_closing(); s.close(); assert_eq!(s.state, State::Closing); } // =========================================================================================// // Tests for the TIME-WAIT state. // =========================================================================================// #[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(false); s.close(); assert_eq!(s.state, State::TimeWait); } #[test] fn test_time_wait_retransmit() { 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 }] ); send!(s, time 5_000, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 1), ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1 + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL })); assert_eq!( s.timer, Timer::Close { expires_at: Instant::from_secs(5) + CLOSE_DELAY } ); } #[test] fn test_time_wait_timeout() { 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 }] ); assert_eq!(s.state, State::TimeWait); recv_nothing!(s, time 60_000); assert_eq!(s.state, State::Closed); } // =========================================================================================// // Tests for the CLOSE-WAIT state. // =========================================================================================// #[test] fn test_close_wait_ack() { let mut s = socket_close_wait(); 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 { seq_number: REMOTE_SEQ + 1 + 1, ack_number: Some(LOCAL_SEQ + 1 + 6), ..SEND_TEMPL } ); } #[test] fn test_close_wait_close() { let mut s = socket_close_wait(); s.close(); assert_eq!(s.state, State::LastAck); sanity!(s, socket_last_ack()); } // =========================================================================================// // Tests for the LAST-ACK state. // =========================================================================================// #[test] fn test_last_ack_fin_ack() { let mut s = socket_last_ack(); recv!( s, [TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL }] ); assert_eq!(s.state, State::LastAck); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 1, ack_number: Some(LOCAL_SEQ + 1 + 1), ..SEND_TEMPL } ); assert_eq!(s.state, State::Closed); } #[test] fn test_last_ack_ack_not_of_fin() { let mut s = socket_last_ack(); recv!( s, [TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL }] ); assert_eq!(s.state, State::LastAck); // ACK received that doesn't ack the FIN: socket should stay in LastAck. send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); assert_eq!(s.state, State::LastAck); // ACK received of fin: socket should change to Closed. send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 1, ack_number: Some(LOCAL_SEQ + 1 + 1), ..SEND_TEMPL } ); assert_eq!(s.state, State::Closed); } #[test] fn test_last_ack_close() { let mut s = socket_last_ack(); s.close(); assert_eq!(s.state, State::LastAck); } // =========================================================================================// // Tests for transitioning through multiple states. // =========================================================================================// #[test] fn test_listen() { let mut s = socket(); s.listen(LISTEN_END).unwrap(); assert_eq!(s.state, State::Listen); } #[test] fn test_three_way_handshake() { let mut s = socket_listen(); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: None, ..SEND_TEMPL } ); assert_eq!(s.state(), State::SynReceived); assert_eq!(s.tuple, Some(TUPLE)); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL }] ); 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); } #[test] fn test_remote_close() { let mut s = socket_established(); 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, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL }] ); s.close(); assert_eq!(s.state, State::LastAck); recv!( s, [TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 1, 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 { // due to reordering, 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 + 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, []); } #[test] fn test_simultaneous_close_combined_fin_ack() { 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 { 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_raced() { let mut s = socket_established(); s.close(); assert_eq!(s.state, State::FinWait1); // Socket receives FIN before it has a chance to send its own FIN 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); // FIN + ack-of-FIN recv!( s, [TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL }] ); assert_eq!(s.state, State::Closing); 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, []); } #[test] fn test_simultaneous_close_raced_with_data() { let mut s = socket_established(); s.send_slice(b"abcdef").unwrap(); s.close(); assert_eq!(s.state, State::FinWait1); // Socket receives FIN before it has a chance to send its own data+FIN 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); // data + FIN + ack-of-FIN recv!( s, [TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }] ); assert_eq!(s.state, State::Closing); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 1, ack_number: Some(LOCAL_SEQ + 1 + 6 + 1), ..SEND_TEMPL } ); assert_eq!(s.state, State::TimeWait); recv!(s, []); } #[test] fn test_fin_with_data() { let mut s = socket_established(); s.send_slice(b"abcdef").unwrap(); s.close(); recv!( s, [TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }] ) } #[test] fn test_mutual_close_with_data_1() { let mut s = socket_established(); s.send_slice(b"abcdef").unwrap(); 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), payload: &b"abcdef"[..], ..RECV_TEMPL }] ); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6 + 1), ..SEND_TEMPL } ); } #[test] fn test_mutual_close_with_data_2() { let mut s = socket_established(); s.send_slice(b"abcdef").unwrap(); 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), payload: &b"abcdef"[..], ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6 + 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 + 6 + 1), ..SEND_TEMPL } ); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1 + 6 + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL }] ); assert_eq!(s.state, State::TimeWait); } // =========================================================================================// // Tests for retransmission on packet loss. // =========================================================================================// #[test] fn test_duplicate_seq_ack() { let mut s = socket_recved(); // remote retransmission send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abcdef"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 6), window_len: 58, ..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_nothing!(s, time 1050); recv!(s, time 2000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL })); } #[test] fn test_data_retransmit_bursts() { let mut s = socket_established(); s.remote_mss = 6; s.send_slice(b"abcdef012345").unwrap(); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::None, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }), exact); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::Psh, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"012345"[..], ..RECV_TEMPL }), exact); recv_nothing!(s, time 0); recv_nothing!(s, time 50); recv!(s, time 1000, Ok(TcpRepr { control: TcpControl::None, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }), exact); recv!(s, time 1500, Ok(TcpRepr { control: TcpControl::Psh, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"012345"[..], ..RECV_TEMPL }), exact); recv_nothing!(s, time 1550); } #[test] fn test_data_retransmit_bursts_half_ack() { let mut s = socket_established(); s.remote_mss = 6; s.send_slice(b"abcdef012345").unwrap(); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::None, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }), exact); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::Psh, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"012345"[..], ..RECV_TEMPL }), exact); // Acknowledge the first packet send!(s, time 5, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6), window_len: 6, ..SEND_TEMPL }); // The second packet should be re-sent. recv!(s, time 1500, Ok(TcpRepr { control: TcpControl::Psh, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"012345"[..], ..RECV_TEMPL }), exact); recv_nothing!(s, time 1550); } #[test] fn test_data_retransmit_bursts_half_ack_close() { let mut s = socket_established(); s.remote_mss = 6; s.send_slice(b"abcdef012345").unwrap(); s.close(); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::None, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }), exact); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"012345"[..], ..RECV_TEMPL }), exact); // Acknowledge the first packet send!(s, time 5, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6), window_len: 6, ..SEND_TEMPL }); // The second packet should be re-sent. recv!(s, time 1500, Ok(TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"012345"[..], ..RECV_TEMPL }), exact); recv_nothing!(s, time 1550); } #[test] fn test_send_data_after_syn_ack_retransmit() { let mut s = socket_syn_received(); recv!(s, time 50, Ok(TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL })); recv!(s, time 750, Ok(TcpRepr { // retransmit control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL })); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); assert_eq!(s.state(), State::Established); 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 }] ) } #[test] fn test_established_retransmit_for_dup_ack() { let mut s = socket_established(); // Duplicate ACKs do not replace the retransmission timer s.send_slice(b"abc").unwrap(); recv!(s, time 1000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abc"[..], ..RECV_TEMPL })); // Retransmit timer is on because all data was sent assert_eq!(s.tx_buffer.len(), 3); // ACK nothing new send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); // Retransmit recv!(s, time 4000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abc"[..], ..RECV_TEMPL })); } #[test] fn test_established_retransmit_reset_after_ack() { let mut s = socket_established(); s.remote_win_len = 6; s.send_slice(b"abcdef").unwrap(); s.send_slice(b"123456").unwrap(); 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 })); send!(s, time 1005, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6), window_len: 6, ..SEND_TEMPL }); recv!(s, time 1010, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"123456"[..], ..RECV_TEMPL })); send!(s, time 1015, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6 + 6), window_len: 6, ..SEND_TEMPL }); recv!(s, time 1020, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"ABCDEF"[..], ..RECV_TEMPL })); } #[test] fn test_established_queue_during_retransmission() { let mut s = socket_established(); s.remote_mss = 6; s.send_slice(b"abcdef123456ABCDEF").unwrap(); recv!(s, time 1000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL })); // this one is dropped recv!(s, time 1005, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"123456"[..], ..RECV_TEMPL })); // this one is received recv!(s, time 1010, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"ABCDEF"[..], ..RECV_TEMPL })); // also dropped recv!(s, time 2000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL })); // retransmission send!(s, time 2005, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6 + 6), ..SEND_TEMPL }); // acknowledgement of both segments recv!(s, time 2010, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"ABCDEF"[..], ..RECV_TEMPL })); // retransmission of only unacknowledged data } #[test] fn test_close_wait_retransmit_reset_after_ack() { let mut s = socket_close_wait(); s.remote_win_len = 6; s.send_slice(b"abcdef").unwrap(); s.send_slice(b"123456").unwrap(); s.send_slice(b"ABCDEF").unwrap(); recv!(s, time 1000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), payload: &b"abcdef"[..], ..RECV_TEMPL })); send!(s, time 1005, TcpRepr { seq_number: REMOTE_SEQ + 1 + 1, ack_number: Some(LOCAL_SEQ + 1 + 6), window_len: 6, ..SEND_TEMPL }); recv!(s, time 1010, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1 + 1), payload: &b"123456"[..], ..RECV_TEMPL })); send!(s, time 1015, TcpRepr { seq_number: REMOTE_SEQ + 1 + 1, ack_number: Some(LOCAL_SEQ + 1 + 6 + 6), window_len: 6, ..SEND_TEMPL }); recv!(s, time 1020, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6 + 6, ack_number: Some(REMOTE_SEQ + 1 + 1), payload: &b"ABCDEF"[..], ..RECV_TEMPL })); } #[test] fn test_fin_wait_1_retransmit_reset_after_ack() { let mut s = socket_established(); s.remote_win_len = 6; s.send_slice(b"abcdef").unwrap(); s.send_slice(b"123456").unwrap(); s.send_slice(b"ABCDEF").unwrap(); s.close(); recv!(s, time 1000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL })); send!(s, time 1005, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6), window_len: 6, ..SEND_TEMPL }); recv!(s, time 1010, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"123456"[..], ..RECV_TEMPL })); send!(s, time 1015, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6 + 6), window_len: 6, ..SEND_TEMPL }); recv!(s, time 1020, Ok(TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1 + 6 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"ABCDEF"[..], ..RECV_TEMPL })); } #[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), ..SEND_TEMPL }); // Send a long string of text divided into several packets // because of previously received "window_len" s.send_slice(b"xxxxxxyyyyyywwwwwwzzzzzz").unwrap(); // This packet is lost recv!(s, time 1000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"xxxxxx"[..], ..RECV_TEMPL })); recv!(s, time 1005, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"yyyyyy"[..], ..RECV_TEMPL })); recv!(s, time 1010, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + (6 * 2), ack_number: Some(REMOTE_SEQ + 1), payload: &b"wwwwww"[..], ..RECV_TEMPL })); recv!(s, time 1015, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + (6 * 3), ack_number: Some(REMOTE_SEQ + 1), payload: &b"zzzzzz"[..], ..RECV_TEMPL })); // First duplicate ACK send!(s, time 1050, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); // Second duplicate ACK send!(s, time 1055, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); // Third duplicate ACK // Should trigger a fast retransmit of dropped packet send!(s, time 1060, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); // Fast retransmit packet recv!(s, time 1100, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"xxxxxx"[..], ..RECV_TEMPL })); recv!(s, time 1105, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"yyyyyy"[..], ..RECV_TEMPL })); recv!(s, time 1110, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + (6 * 2), ack_number: Some(REMOTE_SEQ + 1), payload: &b"wwwwww"[..], ..RECV_TEMPL })); recv!(s, time 1115, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + (6 * 3), ack_number: Some(REMOTE_SEQ + 1), payload: &b"zzzzzz"[..], ..RECV_TEMPL })); // After all was send out, enter *normal* retransmission, // don't stay in fast retransmission. assert!(match s.timer { Timer::Retransmit { expires_at, .. } => expires_at > Instant::from_millis(1115), _ => false, }); // ACK all received segments send!(s, time 1120, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + (6 * 4)), ..SEND_TEMPL }); } #[test] fn test_fast_retransmit_duplicate_detection_with_data() { let mut s = socket_established(); s.send_slice(b"abc").unwrap(); // This is lost recv!(s, time 1000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abc"[..], ..RECV_TEMPL })); // Normal ACK of previously received segment send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); // First duplicate send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); // Second duplicate send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); assert_eq!(s.local_rx_dup_acks, 2, "duplicate ACK counter is not set"); // This packet has content, hence should not be detected // as a duplicate ACK and should reset the duplicate ACK count send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"xxxxxx"[..], ..SEND_TEMPL } ); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1 + 3, ack_number: Some(REMOTE_SEQ + 1 + 6), window_len: 58, ..RECV_TEMPL }] ); assert_eq!( s.local_rx_dup_acks, 0, "duplicate ACK counter is not reset when receiving data" ); } #[test] fn test_fast_retransmit_duplicate_detection() { let mut s = socket_established(); s.remote_mss = 6; // Normal ACK of previously received segment send!(s, time 0, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); // First duplicate, should not be counted as there is nothing to resend send!(s, time 0, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); assert_eq!( s.local_rx_dup_acks, 0, "duplicate ACK counter is set but wound not transmit data" ); // Send a long string of text divided into several packets // because of small remote_mss s.send_slice(b"xxxxxxyyyyyywwwwwwzzzzzz").unwrap(); // This packet is reordered in network recv!(s, time 1000, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"xxxxxx"[..], ..RECV_TEMPL })); recv!(s, time 1005, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"yyyyyy"[..], ..RECV_TEMPL })); recv!(s, time 1010, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + (6 * 2), ack_number: Some(REMOTE_SEQ + 1), payload: &b"wwwwww"[..], ..RECV_TEMPL })); recv!(s, time 1015, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + (6 * 3), ack_number: Some(REMOTE_SEQ + 1), payload: &b"zzzzzz"[..], ..RECV_TEMPL })); // First duplicate ACK send!(s, time 1050, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); // Second duplicate ACK send!(s, time 1055, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..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)), ..SEND_TEMPL }); assert_eq!( s.local_rx_dup_acks, 0, "duplicate ACK counter is not reset when receiving ACK which updates send window" ); // ACK all received segments send!(s, time 1120, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + (6 * 4)), ..SEND_TEMPL }); } #[test] fn test_fast_retransmit_dup_acks_counter() { let mut s = socket_established(); s.send_slice(b"abc").unwrap(); // This is lost recv!(s, time 0, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abc"[..], ..RECV_TEMPL })); send!(s, time 0, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); // A lot of retransmits happen here s.local_rx_dup_acks = u8::max_value() - 1; // Send 3 more ACKs, which could overflow local_rx_dup_acks, // but intended behaviour is that we saturate the bounds // of local_rx_dup_acks send!(s, time 0, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); send!(s, time 0, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); send!(s, time 0, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); assert_eq!( s.local_rx_dup_acks, u8::max_value(), "duplicate ACK count should not overflow but saturate" ); } #[test] fn test_fast_retransmit_zero_window() { let mut s = socket_established(); send!(s, time 1000, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); s.send_slice(b"abc").unwrap(); recv!(s, time 0, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abc"[..], ..RECV_TEMPL })); // 3 dup acks send!(s, time 1050, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); send!(s, time 1050, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); send!(s, time 1050, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), window_len: 0, // boom ..SEND_TEMPL }); // even though we're in "fast retransmit", we shouldn't // force-send anything because the remote's window is full. recv_nothing!(s); } // =========================================================================================// // Tests for window management. // =========================================================================================// #[test] fn test_maximum_segment_size() { let mut s = socket_listen(); s.tx_buffer = SocketBuffer::new(vec![0; 32767]); send!( s, TcpRepr { control: TcpControl::Syn, seq_number: REMOTE_SEQ, ack_number: None, max_seg_size: Some(1000), ..SEND_TEMPL } ); recv!( s, [TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), max_seg_size: Some(BASE_MSS), ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), window_len: 32767, ..SEND_TEMPL } ); s.send_slice(&[0; 1200][..]).unwrap(); recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &[0; 1000][..], ..RECV_TEMPL }) ); } #[test] fn test_close_wait_no_window_update() { let mut s = socket_established(); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &[1, 2, 3, 4], ..SEND_TEMPL } ); assert_eq!(s.state, State::CloseWait); // we ack the FIN, with the reduced window size. recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 6), window_len: 60, ..RECV_TEMPL }) ); let rx_buf = &mut [0; 32]; assert_eq!(s.recv_slice(rx_buf), Ok(4)); // check that we do NOT send a window update even if it has changed. recv_nothing!(s); } #[test] fn test_time_wait_no_window_update() { let mut s = socket_fin_wait_2(); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 2), payload: &[1, 2, 3, 4], ..SEND_TEMPL } ); assert_eq!(s.state, State::TimeWait); // we ack the FIN, with the reduced window size. recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 2, ack_number: Some(REMOTE_SEQ + 6), window_len: 60, ..RECV_TEMPL }) ); let rx_buf = &mut [0; 32]; assert_eq!(s.recv_slice(rx_buf), Ok(4)); // check that we do NOT send a window update even if it has changed. recv_nothing!(s); } // =========================================================================================// // Tests for flow control. // =========================================================================================// #[test] fn test_psh_transmit() { let mut s = socket_established(); s.remote_mss = 6; s.send_slice(b"abcdef").unwrap(); s.send_slice(b"123456").unwrap(); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::None, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }), exact); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::Psh, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"123456"[..], ..RECV_TEMPL }), exact); } #[test] fn test_psh_receive() { let mut s = socket_established(); send!( s, TcpRepr { control: TcpControl::Psh, 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), window_len: 58, ..RECV_TEMPL }] ); } #[test] fn test_zero_window_ack() { let mut s = socket_established(); s.rx_buffer = SocketBuffer::new(vec![0; 6]); s.assembler = Assembler::new(); 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), window_len: 0, ..RECV_TEMPL }] ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 6, ack_number: Some(LOCAL_SEQ + 1), payload: &b"123456"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 6), window_len: 0, ..RECV_TEMPL }) ); } #[test] fn test_zero_window_ack_on_window_growth() { let mut s = socket_established(); s.rx_buffer = SocketBuffer::new(vec![0; 6]); s.assembler = Assembler::new(); 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), window_len: 0, ..RECV_TEMPL }] ); recv_nothing!(s, time 0); s.recv(|buffer| { assert_eq!(&buffer[..3], b"abc"); (3, ()) }) .unwrap(); recv!(s, time 0, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 6), window_len: 3, ..RECV_TEMPL })); recv_nothing!(s, time 0); s.recv(|buffer| { assert_eq!(buffer, b"def"); (buffer.len(), ()) }) .unwrap(); recv!(s, time 0, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 6), window_len: 6, ..RECV_TEMPL })); } #[test] fn test_fill_peer_window() { let mut s = socket_established(); s.remote_mss = 6; s.send_slice(b"abcdef123456!@#$%^").unwrap(); recv!( s, [ TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }, TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"123456"[..], ..RECV_TEMPL }, TcpRepr { seq_number: LOCAL_SEQ + 1 + 6 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"!@#$%^"[..], ..RECV_TEMPL } ] ); } #[test] fn test_announce_window_after_read() { let mut s = socket_established(); s.rx_buffer = SocketBuffer::new(vec![0; 6]); s.assembler = Assembler::new(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), window_len: 3, ..RECV_TEMPL }] ); // Test that `dispatch` updates `remote_last_win` assert_eq!(s.remote_last_win, s.rx_buffer.window() as u16); s.recv(|buffer| (buffer.len(), ())).unwrap(); assert!(s.window_to_update()); recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), window_len: 6, ..RECV_TEMPL }] ); assert_eq!(s.remote_last_win, s.rx_buffer.window() as u16); // Provoke immediate ACK to test that `process` updates `remote_last_win` send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 6, ack_number: Some(LOCAL_SEQ + 1), payload: &b"def"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), window_len: 6, ..RECV_TEMPL }) ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 3, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 9), window_len: 0, ..RECV_TEMPL }) ); assert_eq!(s.remote_last_win, s.rx_buffer.window() as u16); s.recv(|buffer| (buffer.len(), ())).unwrap(); assert!(s.window_to_update()); } // =========================================================================================// // Tests for timeouts. // =========================================================================================// #[test] fn test_listen_timeout() { let mut s = socket_listen(); s.set_timeout(Some(Duration::from_millis(100))); assert_eq!(s.socket.poll_at(&mut s.cx), PollAt::Ingress); } #[test] fn test_connect_timeout() { let mut s = socket(); s.local_seq_no = LOCAL_SEQ; s.socket .connect(&mut s.cx, REMOTE_END, LOCAL_END.port) .unwrap(); s.set_timeout(Some(Duration::from_millis(100))); recv!(s, time 150, Ok(TcpRepr { control: TcpControl::Syn, seq_number: LOCAL_SEQ, ack_number: None, max_seg_size: Some(BASE_MSS), window_scale: Some(0), sack_permitted: true, ..RECV_TEMPL })); assert_eq!(s.state, State::SynSent); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(250)) ); recv!(s, time 250, Ok(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 1, ack_number: Some(TcpSeqNumber(0)), window_scale: None, ..RECV_TEMPL })); assert_eq!(s.state, State::Closed); } #[test] fn test_established_timeout() { let mut s = socket_established(); s.set_timeout(Some(Duration::from_millis(1000))); recv_nothing!(s, time 250); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(1250)) ); s.send_slice(b"abcdef").unwrap(); assert_eq!(s.socket.poll_at(&mut s.cx), PollAt::Now); recv!(s, time 255, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL })); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(955)) ); recv!(s, time 955, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL })); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(1255)) ); recv!(s, time 1255, Ok(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL })); assert_eq!(s.state, State::Closed); } #[test] fn test_established_keep_alive_timeout() { let mut s = socket_established(); s.set_keep_alive(Some(Duration::from_millis(50))); s.set_timeout(Some(Duration::from_millis(100))); recv!(s, time 100, Ok(TcpRepr { seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), payload: &[0], ..RECV_TEMPL })); recv_nothing!(s, time 100); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(150)) ); send!(s, time 105, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(155)) ); recv!(s, time 155, Ok(TcpRepr { seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), payload: &[0], ..RECV_TEMPL })); recv_nothing!(s, time 155); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(205)) ); recv_nothing!(s, time 200); recv!(s, time 205, Ok(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL })); recv_nothing!(s, time 205); assert_eq!(s.state, State::Closed); } #[test] fn test_fin_wait_1_timeout() { let mut s = socket_fin_wait_1(); s.set_timeout(Some(Duration::from_millis(1000))); recv!(s, time 100, Ok(TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL })); recv!(s, time 1100, Ok(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 1 + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL })); assert_eq!(s.state, State::Closed); } #[test] fn test_last_ack_timeout() { let mut s = socket_last_ack(); s.set_timeout(Some(Duration::from_millis(1000))); recv!(s, time 100, Ok(TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL })); recv!(s, time 1100, Ok(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 1 + 1, ack_number: Some(REMOTE_SEQ + 1 + 1), ..RECV_TEMPL })); assert_eq!(s.state, State::Closed); } #[test] fn test_closed_timeout() { let mut s = socket_established(); s.set_timeout(Some(Duration::from_millis(200))); s.remote_last_ts = Some(Instant::from_millis(100)); s.abort(); assert_eq!(s.socket.poll_at(&mut s.cx), PollAt::Now); recv!(s, time 100, Ok(TcpRepr { control: TcpControl::Rst, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL })); assert_eq!(s.socket.poll_at(&mut s.cx), PollAt::Ingress); } // =========================================================================================// // Tests for keep-alive. // =========================================================================================// #[test] fn test_responds_to_keep_alive() { let mut s = socket_established(); send!( s, TcpRepr { seq_number: REMOTE_SEQ, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }) ); } #[test] fn test_sends_keep_alive() { let mut s = socket_established(); s.set_keep_alive(Some(Duration::from_millis(100))); // drain the forced keep-alive packet assert_eq!(s.socket.poll_at(&mut s.cx), PollAt::Now); recv!(s, time 0, Ok(TcpRepr { seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), payload: &[0], ..RECV_TEMPL })); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(100)) ); recv_nothing!(s, time 95); recv!(s, time 100, Ok(TcpRepr { seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), payload: &[0], ..RECV_TEMPL })); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(200)) ); recv_nothing!(s, time 195); recv!(s, time 200, Ok(TcpRepr { seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), payload: &[0], ..RECV_TEMPL })); send!(s, time 250, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL }); assert_eq!( s.socket.poll_at(&mut s.cx), PollAt::Time(Instant::from_millis(350)) ); recv_nothing!(s, time 345); recv!(s, time 350, Ok(TcpRepr { seq_number: LOCAL_SEQ, ack_number: Some(REMOTE_SEQ + 1), payload: &b"\x00"[..], ..RECV_TEMPL })); } // =========================================================================================// // Tests for time-to-live configuration. // =========================================================================================// #[test] fn test_set_hop_limit() { let mut s = socket_syn_received(); s.set_hop_limit(Some(0x2a)); assert_eq!( s.socket.dispatch(&mut s.cx, |_, (ip_repr, _)| { assert_eq!(ip_repr.hop_limit(), 0x2a); Ok::<_, ()>(()) }), Ok(()) ); // assert that user-configurable settings are kept, // see https://github.com/smoltcp-rs/smoltcp/issues/601. s.reset(); assert_eq!(s.hop_limit(), Some(0x2a)); } #[test] #[should_panic(expected = "the time-to-live value of a packet must not be zero")] fn test_set_hop_limit_zero() { let mut s = socket_syn_received(); s.set_hop_limit(Some(0)); } // =========================================================================================// // Tests for reassembly. // =========================================================================================// #[test] fn test_out_of_order() { let mut s = socket_established(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 3, ack_number: Some(LOCAL_SEQ + 1), payload: &b"def"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), ..RECV_TEMPL }) ); s.recv(|buffer| { assert_eq!(buffer, b""); (buffer.len(), ()) }) .unwrap(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abcdef"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 6), window_len: 58, ..RECV_TEMPL }) ); s.recv(|buffer| { assert_eq!(buffer, b"abcdef"); (buffer.len(), ()) }) .unwrap(); } #[test] fn test_buffer_wraparound_rx() { let mut s = socket_established(); s.rx_buffer = SocketBuffer::new(vec![0; 6]); s.assembler = Assembler::new(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); s.recv(|buffer| { assert_eq!(buffer, b"abc"); (buffer.len(), ()) }) .unwrap(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 3, ack_number: Some(LOCAL_SEQ + 1), payload: &b"defghi"[..], ..SEND_TEMPL } ); let mut data = [0; 6]; assert_eq!(s.recv_slice(&mut data[..]), Ok(6)); assert_eq!(data, &b"defghi"[..]); } #[test] fn test_buffer_wraparound_tx() { let mut s = socket_established(); s.set_nagle_enabled(false); s.tx_buffer = SocketBuffer::new(vec![b'.'; 9]); assert_eq!(s.send_slice(b"xxxyyy"), Ok(6)); assert_eq!(s.tx_buffer.dequeue_many(3), &b"xxx"[..]); assert_eq!(s.tx_buffer.len(), 3); // "abcdef" not contiguous in tx buffer assert_eq!(s.send_slice(b"abcdef"), Ok(6)); recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"yyyabc"[..], ..RECV_TEMPL }) ); recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"def"[..], ..RECV_TEMPL }) ); } // =========================================================================================// // Tests for graceful vs ungraceful rx close // =========================================================================================// #[test] fn test_rx_close_fin() { let mut s = socket_established(); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); assert_eq!(s.recv(|_| (0, ())), Err(RecvError::Finished)); } #[test] fn test_rx_close_fin_in_fin_wait_1() { let mut s = socket_fin_wait_1(); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); assert_eq!(s.state, State::Closing); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); assert_eq!(s.recv(|_| (0, ())), Err(RecvError::Finished)); } #[test] fn test_rx_close_fin_in_fin_wait_2() { let mut s = socket_fin_wait_2(); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); assert_eq!(s.state, State::TimeWait); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); assert_eq!(s.recv(|_| (0, ())), Err(RecvError::Finished)); } #[test] fn test_rx_close_fin_with_hole() { let mut s = socket_established(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); send!( s, TcpRepr { control: TcpControl::Fin, seq_number: REMOTE_SEQ + 1 + 6, ack_number: Some(LOCAL_SEQ + 1), payload: &b"ghi"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), window_len: 61, ..RECV_TEMPL }) ); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); s.recv(|data| { assert_eq!(data, b""); (0, ()) }) .unwrap(); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ + 1 + 9, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); // Error must be `Illegal` even if we've received a FIN, // because we are missing data. assert_eq!(s.recv(|_| (0, ())), Err(RecvError::InvalidState)); } #[test] fn test_rx_close_rst() { let mut s = socket_established(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ + 1 + 3, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); assert_eq!(s.recv(|_| (0, ())), Err(RecvError::InvalidState)); } #[test] fn test_rx_close_rst_with_hole() { let mut s = socket_established(); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 6, ack_number: Some(LOCAL_SEQ + 1), payload: &b"ghi"[..], ..SEND_TEMPL }, Some(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), window_len: 61, ..RECV_TEMPL }) ); send!( s, TcpRepr { control: TcpControl::Rst, seq_number: REMOTE_SEQ + 1 + 9, ack_number: Some(LOCAL_SEQ + 1), ..SEND_TEMPL } ); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); assert_eq!(s.recv(|_| (0, ())), Err(RecvError::InvalidState)); } // =========================================================================================// // Tests for delayed ACK // =========================================================================================// #[test] fn test_delayed_ack() { let mut s = socket_established(); s.set_ack_delay(Some(ACK_DELAY_DEFAULT)); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); // No ACK is immediately sent. recv_nothing!(s); // After 10ms, it is sent. recv!(s, time 11, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), window_len: 61, ..RECV_TEMPL })); } #[test] fn test_delayed_ack_win() { let mut s = socket_established(); s.set_ack_delay(Some(ACK_DELAY_DEFAULT)); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); // Reading the data off the buffer should cause a window update. s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); // However, no ACK or window update is immediately sent. recv_nothing!(s); // After 10ms, it is sent. recv!(s, time 11, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), ..RECV_TEMPL })); } #[test] fn test_delayed_ack_reply() { let mut s = socket_established(); s.set_ack_delay(Some(ACK_DELAY_DEFAULT)); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); s.recv(|data| { assert_eq!(data, b"abc"); (3, ()) }) .unwrap(); s.send_slice(&b"xyz"[..]).unwrap(); // Writing data to the socket causes ACK to not be delayed, // because it is immediately sent with the data. recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 3), payload: &b"xyz"[..], ..RECV_TEMPL }) ); } #[test] fn test_delayed_ack_every_second_packet() { let mut s = socket_established(); s.set_ack_delay(Some(ACK_DELAY_DEFAULT)); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); // No ACK is immediately sent. recv_nothing!(s); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 3, ack_number: Some(LOCAL_SEQ + 1), payload: &b"def"[..], ..SEND_TEMPL } ); // Every 2nd packet, ACK is sent without delay. recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 6), window_len: 58, ..RECV_TEMPL }) ); } #[test] fn test_delayed_ack_three_packets() { let mut s = socket_established(); s.set_ack_delay(Some(ACK_DELAY_DEFAULT)); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abc"[..], ..SEND_TEMPL } ); // No ACK is immediately sent. recv_nothing!(s); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 3, ack_number: Some(LOCAL_SEQ + 1), payload: &b"def"[..], ..SEND_TEMPL } ); send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1 + 6, ack_number: Some(LOCAL_SEQ + 1), payload: &b"ghi"[..], ..SEND_TEMPL } ); // Every 2nd (or more) packet, ACK is sent without delay. recv!( s, Ok(TcpRepr { seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1 + 9), window_len: 55, ..RECV_TEMPL }) ); } // =========================================================================================// // Tests for Nagle's Algorithm // =========================================================================================// #[test] fn test_nagle() { let mut s = socket_established(); s.remote_mss = 6; 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 }] ); // If there's data in flight, full segments get sent. 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 }] ); s.send_slice(b"aaabbbccc").unwrap(); // If there's data in flight, not-full segments don't get sent. recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1 + 6 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"aaabbb"[..], ..RECV_TEMPL }] ); // Data gets ACKd, so there's no longer data in flight send!( s, TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1 + 6 + 6 + 6), ..SEND_TEMPL } ); // Now non-full segment gets sent. recv!( s, [TcpRepr { seq_number: LOCAL_SEQ + 1 + 6 + 6 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"ccc"[..], ..RECV_TEMPL }] ); } #[test] fn test_final_packet_in_stream_doesnt_wait_for_nagle() { let mut s = socket_established(); s.remote_mss = 6; s.send_slice(b"abcdef0").unwrap(); s.socket.close(); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::None, seq_number: LOCAL_SEQ + 1, ack_number: Some(REMOTE_SEQ + 1), payload: &b"abcdef"[..], ..RECV_TEMPL }), exact); recv!(s, time 0, Ok(TcpRepr { control: TcpControl::Fin, seq_number: LOCAL_SEQ + 1 + 6, ack_number: Some(REMOTE_SEQ + 1), payload: &b"0"[..], ..RECV_TEMPL }), exact); } // =========================================================================================// // Tests for packet filtering. // =========================================================================================// #[test] fn test_doesnt_accept_wrong_port() { let mut s = socket_established(); s.rx_buffer = SocketBuffer::new(vec![0; 6]); s.assembler = Assembler::new(); let tcp_repr = TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), dst_port: LOCAL_PORT + 1, ..SEND_TEMPL }; assert!(!s.socket.accepts(&mut s.cx, &SEND_IP_TEMPL, &tcp_repr)); let tcp_repr = TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), src_port: REMOTE_PORT + 1, ..SEND_TEMPL }; assert!(!s.socket.accepts(&mut s.cx, &SEND_IP_TEMPL, &tcp_repr)); } #[test] fn test_doesnt_accept_wrong_ip() { let mut s = socket_established(); let tcp_repr = TcpRepr { seq_number: REMOTE_SEQ + 1, ack_number: Some(LOCAL_SEQ + 1), payload: &b"abcdef"[..], ..SEND_TEMPL }; let ip_repr = IpReprIpvX(IpvXRepr { src_addr: REMOTE_ADDR, dst_addr: LOCAL_ADDR, next_header: IpProtocol::Tcp, payload_len: tcp_repr.buffer_len(), hop_limit: 64, }); assert!(s.socket.accepts(&mut s.cx, &ip_repr, &tcp_repr)); let ip_repr_wrong_src = IpReprIpvX(IpvXRepr { src_addr: OTHER_ADDR, dst_addr: LOCAL_ADDR, next_header: IpProtocol::Tcp, payload_len: tcp_repr.buffer_len(), hop_limit: 64, }); assert!(!s.socket.accepts(&mut s.cx, &ip_repr_wrong_src, &tcp_repr)); let ip_repr_wrong_dst = IpReprIpvX(IpvXRepr { src_addr: REMOTE_ADDR, dst_addr: OTHER_ADDR, next_header: IpProtocol::Tcp, payload_len: tcp_repr.buffer_len(), hop_limit: 64, }); assert!(!s.socket.accepts(&mut s.cx, &ip_repr_wrong_dst, &tcp_repr)); } // =========================================================================================// // Timer tests // =========================================================================================// #[test] fn test_timer_retransmit() { const RTO: Duration = Duration::from_millis(100); let mut r = Timer::new(); assert_eq!(r.should_retransmit(Instant::from_secs(1)), None); r.set_for_retransmit(Instant::from_millis(1000), RTO); assert_eq!(r.should_retransmit(Instant::from_millis(1000)), None); assert_eq!(r.should_retransmit(Instant::from_millis(1050)), None); assert_eq!( r.should_retransmit(Instant::from_millis(1101)), Some(Duration::from_millis(101)) ); r.set_for_retransmit(Instant::from_millis(1101), RTO); assert_eq!(r.should_retransmit(Instant::from_millis(1101)), None); assert_eq!(r.should_retransmit(Instant::from_millis(1150)), None); assert_eq!(r.should_retransmit(Instant::from_millis(1200)), None); assert_eq!( r.should_retransmit(Instant::from_millis(1301)), Some(Duration::from_millis(300)) ); r.set_for_idle(Instant::from_millis(1301), None); assert_eq!(r.should_retransmit(Instant::from_millis(1350)), None); } #[test] fn test_rtt_estimator() { let mut r = RttEstimator::default(); let rtos = &[ 751, 766, 755, 731, 697, 656, 613, 567, 523, 484, 445, 411, 378, 350, 322, 299, 280, 261, 243, 229, 215, 206, 197, 188, ]; for &rto in rtos { r.sample(100); assert_eq!(r.retransmission_timeout(), Duration::from_millis(rto)); } } }