Commit Graph

221 Commits

Author SHA1 Message Date
whitequark 760174048d Get rid of IpPayload and indirection in Socket::dispatch.
This was just completely pointless, and only served to obfuscate
the data path and make testing harder.
2017-08-28 03:56:34 +00:00
whitequark 1d01189278 Use FnOnce, not FnMut, in Socket::dispatch() functions.
There was never any reason to use FnMut and this significantly
simplifies the job of the borrow checker.
2017-08-28 00:59:33 +00:00
whitequark 4878f0f1d6 Fix a TCP retransmit loop after transition from SYN-SENT to ESTABLISHED. 2017-08-25 06:47:12 +00:00
whitequark 3035ef07fb Fix a bug that caused TCP packets with PSH bit to be dropped. 2017-08-25 06:27:00 +00:00
whitequark afdf73ffef TcpRepr::push → TcpControl::Psh.
This is done for simplification. FIN implies PSH, RST doesn't have
any meaning with PSH, and SYN|PSH only makes sense in the context
of TCP Fast Open, in the context of which, any data in the original
SYN already implies PSH.
2017-08-25 06:05:17 +00:00
whitequark 5396687d52 Immediately ACK payload in response to TCP packets that have any.
This will lower the average software RTT by about a factor of two.
2017-08-25 05:50:43 +00:00
whitequark 5b2de544c8 Radically simplify and optimize TCP packet dispatch.
This commit completely reworks packet dispatch in TCP sockets,
and brings significant improvements to processing as well.

In particular:
  * Challenge ACKs now do not reset retransmit timer; instead,
    TcpSocket::process directly returns a TcpRepr without altering
    any internal state at all.
  * Retransmit and close (aka TIME-WAIT) timers are unified
    and restructured into a enum that actually matches semantics
    of the timers.
  * If a packet cannot be emitted, no internal state is changed.
  * The dispatch of RST packets in case of connection abort
    is brought in line with dispatch of all other packets.
  * Packet dispatch now follows a series of steps with clean
    separation of concerns, like packet processing:
      1. If we should retransmit, update state to assume that
         all in-flight packets are lost.
      2. Prepare the packet that would be sent next, considering
         the in-flight packets, if any.
      3. Check if the packet contains anything new, or it's the same
         as the one already in flight. If it is, bail.
      4. Finalize and try to actually transmit the packet.
         If we can't do that, bail.
      5. Update the internal state to reflect that the packet
         we've just sent is in flight.
2017-08-25 03:53:31 +00:00
whitequark a0d359fc53 Make TCP packets not matching socket state return Error::Dropped.
Error::Malformed is only for internally inconsistent packets,
like SYN|FIN.
2017-08-25 03:52:30 +00:00
whitequark 9d0084171f Rework responses to TCP packets and factor in RST replies to TcpSocket. 2017-08-22 22:32:05 +00:00
whitequark f9c6c0249b Listening TCP sockets should reject, not drop, ACKs. 2017-08-21 07:29:32 +00:00
whitequark 39f328b80f Add TcpSocket::{peek,peek_slice}. 2017-08-21 07:28:38 +00:00
whitequark e0d8fcfb72 Emit exceptional events with the DEBUG log level, not TRACE. 2017-08-01 11:21:58 +00:00
whitequark db5ecb353a Only return Err(Rejected) from TcpSocket::process on endpoint mismatch.
Otherwise, a future SocketSet that tries to route packets by using
IP/port numbers instead of brute force would result in different
semantics.
2017-08-01 11:15:12 +00:00
whitequark 7825bc6070 Implement fmt::Write for TcpSocket. 2017-07-30 06:59:01 +00:00
whitequark ae903e8841 Add UdpSocket::is_open, similar to TcpSocket::is_open in function.
Fixes #31.
2017-07-30 01:17:58 +00:00
whitequark 02f005a2bb Put the debug_id field first in sockets.
This has been annoying me far too long.
2017-07-28 11:55:59 +00:00
whitequark ad12573f62 Rework and test UDP sockets.
Before, errors such as packets not fitting into a buffer would have
resulted in panics, and errors such as unbound sockets were
simply ignored.
2017-07-27 22:30:01 +00:00
whitequark 8d8a4ea583 Get rid of Result<_, ()>.
The use of this type has several drawbacks:
  * It does not allow distinguishing between different error
    conditions. In fact, we wrongly conflated some of them
    before this commit.
  * It does not allow propagation via ? and requires manual use
    of map_err, which is especially tiresome for downstream code.
  * It prevents us from expanding the set of error conditions
    even if right now we have only one.
  * It prevents us from blanket using Result<T> everywhere
    (a nitpick at most).

Instead, use Result<T, Error> everywhere, and differentiate error
conditions where applicable.
2017-07-27 13:55:47 +00:00
whitequark 8a2432dcd7 Rework error handling in TcpSocket::connect. 2017-07-27 12:27:33 +00:00
whitequark 24bb0eab9d Update a stale docstring. 2017-07-27 11:26:39 +00:00
whitequark a3423b35f4 as_unspecified → to_unspecified 2017-07-27 11:26:07 +00:00
whitequark 38afc64f61 Accept TCP FIN packets in SYN-RECEIVED state. 2017-07-23 23:51:56 +00:00
whitequark 1c41f2d7fa Fix determination of local address from incoming packets.
We've advertised this capability before in examples, but it did not
actually work.
2017-07-23 23:07:55 +00:00
whitequark bdfc47d633 Log correct delay when performing TCP retransmit.
Before, the delay was erroneously multiplied by 2 and also did not
take processing delay into account.
2017-07-23 05:09:38 +00:00
whitequark 5556f09351 Annotate all simple getters with #[inline]. 2017-07-04 18:46:36 +00:00
whitequark 3f9805b2c1 Remove *Socket::{process,dispatch} from public interface.
These no longer have to be public, since our required Rust version
has pub(crate).
2017-06-30 20:55:46 +00:00
whitequark 938fb99070 In {Tcp,Udp}Socket::process, make protocol check an assertion.
We filter sockets by type upstream of the process() calls.
2017-06-30 19:17:14 +00:00
whitequark cbf6e5cdbc Try to trigger fast retransmit when we detect a missing TCP segment.
The changes in this commit affect the following scenario:
  * Remote end sends octets 1..2, they are delivered and buffered
    on local end;
  * Remote end sends octets 3..4, they are lost;
  * Remote end sends octets 5..6, they are delivered but cannot
    be buffered on local end because we don't perform reassembly.

Before this commit, we would silently drop the segment with octets
5..6, relying on retransmission timer on the remote end. This works,
but can result in severe decrease in throughput. After this commit,
we send a duplicate ACK, which may trigger fast retransmit, if
implemented by the congestion control algorithm on the remote end.
2017-06-26 08:44:07 +00:00
whitequark 050dd788c1 Set TCP PSH flag when sending the last buffered data. 2017-06-25 23:12:30 +00:00
whitequark b86d22701d Expose PSH flag in TcpRepr. 2017-06-25 08:20:25 +00:00
whitequark db75f70fa3 Fix a few typos in TCP socket code (NFC). 2017-06-25 08:05:37 +00:00
whitequark 74823b0dff try! → ? 2017-06-24 16:34:32 +00:00
whitequark 8b27330c8b Do not attempt to validate length of packets being emitted.
This is a form of an uninitialized read bug; although safe it caused
panics. In short, transmit buffers received from the network stack
should be considered uninitialized (in practice they will often
contain previously transmitted packets or parts thereof). Wrapping
them with the only method we had (e.g. Ipv4Packet) treated the buffer
as if it contained a valid incoming packet, which can easily fail
with Error::Truncated.

This commit splits every `fn new(buffer: T) -> Result<Self, Error>`
method on a `Packet` into three smaller ones:
  * `fn check_len(&self) -> Result<(), Error>`, purely a validator;
  * `fn new(T) -> Self`, purely a wrapper;
  * `fn new_checked(T) -> Result<Self, Error>`, a validating wrapper.

This makes it easy to process ingress packets (using `new_checked`),
egress packets (using `new`), and, if needed, maintain the invariants
at any point during packet construction (using `check_len`).

Fixes #17.
2017-06-24 11:42:32 +00:00
whitequark f29b610801 Remove accidentally committed change. 2017-05-29 17:15:35 +00:00
whitequark 91ef5c60c3 Add packet shaping to the fault injector. 2017-05-29 10:53:30 +00:00
whitequark 73bb4b8593 Implement TCP TIME-WAIT timeouts. 2017-04-21 16:01:49 +00:00
whitequark 555825e49e Clamp TCP receive window to MSS multiplied by maximum burst size.
This is a conservative bound; if we don't have enough buffers
to receive more than four segments, clearly we shouldn't advertise
our ability to.

It however will only work reliably with exactly one TCP connection
continuously receiving; for two, another window adjustment mechanism
will be needed for reliable reception.
2017-03-07 11:21:49 +00:00
whitequark 1d46ccf432 fn Device::mtu() -> usize → Device::limits() -> DeviceLimits 2017-03-07 11:10:26 +00:00
whitequark c73298f01e Improve handling of TCP ACK packets in FIN-* states.
Previously, sockets could get stuck in the CLOSING state, after
the sequence described in the new test_mutual_close_with_data_2.
The root cause was that some state machine transitions got
folded into ACK handling.

Now, all transitions are handled in the same match statement,
and ACK handling is broken up around it.
2017-03-07 10:17:30 +00:00
whitequark 0836bc949a Fix condition for acceptable RST|ACK in TCP SYN-SENT state. 2017-03-05 05:31:12 +00:00
whitequark cd894460f5 Implement the TCP SYN-SENT state. 2017-03-05 03:53:04 +00:00
whitequark e36e05905c Fix an incorrect tracing message. 2017-03-05 03:16:15 +00:00
whitequark 255d69d63b Fix the TCP MSS calculation. 2017-01-31 11:39:33 +00:00
whitequark da4900a02b Fix an incorrect payload length when sending TCP MSS option. 2017-01-27 03:35:22 +00:00
whitequark d6b7623c37 Receive the TCP MSS option and act on it. 2017-01-27 03:06:52 +00:00
whitequark bc1d65ea89 Send the TCP MSS option. 2017-01-27 02:56:27 +00:00
whitequark 077513fda6 Add support for TCP MSS option in TCP representation. 2017-01-27 02:56:27 +00:00
whitequark 4267ad2635 Fix an inaccurate comment. 2017-01-26 22:04:05 +00:00
whitequark 9b8671ce15 Fix the TCP FIN emission with queued data rolling over TX buffer. 2017-01-25 06:20:57 +00:00
whitequark 9fbb5cfff1 Fix the TCP ACK handling in FIN-WAIT-1 state with queued data. 2017-01-25 06:01:58 +00:00
whitequark 68064c3725 Refactor the TCP ACK handling in ESTABLISHED/CLOSE-WAIT states. 2017-01-25 05:50:14 +00:00
whitequark 8b292c6dd8 Don't switch TCP state from FIN-WAIT-1 to FIN-WAIT-2 with queued data. 2017-01-25 05:36:42 +00:00
whitequark bef01740a7 If a TCP FIN|ACK also ACKs our FIN, transition to TIME-WAIT. 2017-01-25 03:58:03 +00:00
whitequark 497aa5919a Correctly treat TCP ACKs that acknowledge both data and a FIN. 2017-01-23 22:17:04 +00:00
whitequark 92fde3d18b Don't send TCP FIN flag yet if next segment will also have data. 2017-01-23 12:07:07 +00:00
whitequark 507af2b0c3 Reset the TCP retransmit timer on valid ACK if transmit half is open. 2017-01-23 11:34:36 +00:00
whitequark 62f094d276 Fix build with no alloc or collections. 2017-01-22 20:29:45 +00:00
whitequark 34d32f67a2 Gate the really verbose log messages behind a feature.
Otherwise, trying to use the socket buffers instead of BufReader/
BufWriter is doomed to overwhelm the application logic.
2017-01-19 12:23:32 +00:00
whitequark 15a344f1d3 Don't respond with RST to ACKs in TCP LISTEN state.
These packets may have been destined for a different socket.
2017-01-17 04:43:51 +00:00
whitequark 591993014e Reject, not accept, TCP RST packets in LISTEN state.
These packets may have been destined for a different socket.
2017-01-17 04:33:37 +00:00
whitequark 74d1eb86b6 Add TcpSocket::abort(). 2017-01-17 01:24:51 +00:00
whitequark a75f7d4bf0 Reject all TCP packets in the CLOSED state. 2017-01-17 00:24:47 +00:00
whitequark 4da2598ea7 Properly document TCP state machine query methods. 2017-01-17 00:21:07 +00:00
whitequark f126eab193 Distinguish sockets by debug identifiers (socket set indexes). 2017-01-16 23:35:21 +00:00
whitequark 40716a348d Do not send RST in response to invalid SEQ or ACK. 2017-01-16 16:58:45 +00:00
whitequark bd01cdef78 Always display meaningful endpoint in trace messages. 2017-01-16 16:34:24 +00:00
whitequark 51d8afe579 Fix inverted meaning of TcpSocketBuffer::empty(). 2017-01-15 11:00:04 +00:00
whitequark c0697cf37d Add lots of sanity checking to TCP test helpers. 2017-01-14 12:56:58 +00:00
whitequark a864157feb Do not try to retransmit SYN as if it was in data stream. 2017-01-14 12:18:00 +00:00
whitequark 578d7bce5f Calculate IP payload length from the total length field.
Before this commit, IP payload length was calculated by subtracting
the IP header length from the total underlying buffer length, which
fails if the underlying buffer has padding, e.g. like Ethernet
does.
2017-01-14 11:07:06 +00:00
whitequark 8b04d8bebe Try to get TCP state query methods into a saner state. 2017-01-14 09:13:25 +00:00
whitequark f7bc7fe364 Do not use UTF-8 in net_trace!().
This may interact badly with other tooling.
2017-01-14 07:10:20 +00:00
whitequark dc8809288f Fix a bug that caused .send();.close(); to result in a lost FIN. 2017-01-14 06:59:58 +00:00
whitequark cca835a45a Update TcpSocket::{can,may}_{send,recv} APIs. 2017-01-14 06:59:58 +00:00
whitequark 67430aa589 Use the managed crate. 2017-01-10 11:04:00 +00:00
whitequark 27ccfc1bb0 Implement TCP retransmission. 2016-12-31 08:35:46 +00:00
whitequark 818e98f47a TCP: retransmit ACK when receiving duplicate SEQ. 2016-12-31 01:33:46 +00:00
whitequark be68066152 #[inline(always)] → #[inline] 2016-12-30 16:55:31 +00:00
whitequark 287affb447 Implement the TCP TIME-WAIT state. 2016-12-28 05:33:12 +00:00
whitequark 94963faf12 Implement the TCP CLOSING state. 2016-12-28 04:56:49 +00:00
whitequark 3e7a1ee575 Implement the TCP FIN-WAIT-2 state. 2016-12-28 04:10:17 +00:00
whitequark 9dc931dbe2 Implement the TCP FIN-WAIT-1 state. 2016-12-28 04:02:43 +00:00
whitequark 71268ace88 Get rid of the #![feature(const_fn)]. 2016-12-28 00:08:51 +00:00
whitequark df69303624 Fix state names in documentation. 2016-12-27 23:28:57 +00:00
whitequark 979cd4c1bf Implement the TCP LAST-ACK state. 2016-12-27 23:27:33 +00:00
whitequark 874264503d Implement the TCP close operation. 2016-12-27 22:43:16 +00:00
whitequark feaef0d7c4 Fix TCP sequence number in multiple consecutive non-ACKed data packets. 2016-12-27 20:39:46 +00:00
whitequark 17f96ba929 Fix TcpSocket::can_recv(). 2016-12-27 20:17:46 +00:00
whitequark 71d1b4061f Fix ACK validation of TCP RST packets. 2016-12-27 20:17:35 +00:00
whitequark 867dda659d Fix several TCP out-of-bounds reads from the transmit buffer. 2016-12-27 20:17:03 +00:00
whitequark 69427c9e2f Add TcpSocket::is_connected(). 2016-12-27 18:54:45 +00:00
whitequark 6b592742fd Use the correct wrapping operations on TCP sequence numbers. 2016-12-27 18:34:13 +00:00
whitequark bbff907e87 Fix examples. 2016-12-27 18:04:39 +00:00
whitequark a8fc4fd832 Improve the user-facing TCP socket API. 2016-12-27 17:49:40 +00:00
whitequark 09040f3e91 Accept TCP ACK packets in CLOSE_WAIT state. 2016-12-27 14:13:42 +00:00
whitequark d11016b138 Simplify TCP ACK handling. 2016-12-27 14:04:30 +00:00
whitequark 751a2269c3 Add support for TCP FIN in ESTABLISHED state. 2016-12-27 13:34:48 +00:00
whitequark 79553e81d4 Fix TCP incoming sequence number check. 2016-12-26 17:24:37 +00:00
whitequark 2d562c10fa Add support for multiple outgoing in-flight TCP packets. 2016-12-26 16:59:39 +00:00
whitequark 3917ba5836 Shrink the buffers in examples for ease of testing. 2016-12-26 16:29:33 +00:00
whitequark a8b4ed2deb Implement the userspace side of TCP sockets. 2016-12-26 15:05:46 +00:00
whitequark 0e20ea9205 Implement TCP data transmission. 2016-12-26 14:24:17 +00:00
whitequark 0bf822c77e Implement TCP RST handling. 2016-12-26 13:54:26 +00:00
whitequark 83f886826f Validate ACK for TCP RST packets. 2016-12-26 13:10:39 +00:00
whitequark f468f47959 Validate ACK even in TCP LISTEN state. 2016-12-26 13:00:39 +00:00
whitequark 2de98aea06 Add tests for TCP error conditions. 2016-12-26 12:44:41 +00:00
whitequark 25d453447f Generalize the TCP tests to accept multiple packets. 2016-12-26 12:38:40 +00:00
whitequark ea78053dc1 Factor out IpRepr into the wire module. 2016-12-26 11:20:20 +00:00
whitequark ea07e79bdf Group IP header parts in the socket layer as struct IpRepr. 2016-12-26 10:06:49 +00:00
whitequark b5a9917950 Implement TCP data acknowledgement. 2016-12-25 11:19:50 +00:00
whitequark 0ae27678a0 Implement TCP data reception. 2016-12-25 11:09:50 +00:00
whitequark bdfb99ea16 Validate TCP ACKs. 2016-12-25 09:22:49 +00:00
whitequark fa1a51b90a Add tests for TCP state machine. 2016-12-24 23:06:42 +00:00
whitequark f5f0b8e435 Add basic TCP three-way handshake. 2016-12-23 08:05:50 +00:00
whitequark 3c05139204 Add logging capability. 2016-12-23 07:59:38 +00:00
whitequark 6539019f19 Get rid of explicit backlog. 2016-12-23 07:34:10 +00:00
whitequark 3bd715e1bc Use signed integers to represent TCP sequence numbers. 2016-12-23 07:34:07 +00:00
whitequark 1ad8f9c9bd Implement conversion of incoming TCP connections into TCP streams. 2016-12-20 22:57:21 +00:00
whitequark bddb5f9127 Implement TCP server sockets. 2016-12-20 19:51:52 +00:00
whitequark a3481537d9 Add some sanity into buffer names (avoid clases with wire::*). 2016-12-20 13:56:59 +00:00
whitequark 71fc81b7c5 Implement TCP stream ring buffers. 2016-12-18 19:40:50 +00:00