From RFC 793 s3.9 p58 Event Processing:
If RECEIVE Call arrives in CLOSED state and the user has access to such a
connection, the return should be "error: connection does not exist"
Fixes#1598
PiperOrigin-RevId: 293494287
Tests 65k connection attempts on common types of sockets to check for port
leaks.
Also fixes a bug where dual-stack sockets wouldn't properly re-queue
segments received while closing.
PiperOrigin-RevId: 293241166
As per RFC 2464 section 7, an IPv6 packet with a multicast destination
address is transmitted to the mapped Ethernet multicast address.
Test:
- ipv6.TestLinkResolution
- stack_test.TestDADResolve
- stack_test.TestRouterSolicitation
PiperOrigin-RevId: 292610529
When sending a RST on shutdown we need to double check the
state after acquiring the work mutex as the endpoint could
have transitioned out of a connected state from the time
we checked it and we acquired the workMutex.
I added two tests but sadly neither reproduce the panic. I am
going to leave the tests in as they are good to have anyway.
PiperOrigin-RevId: 292393800
Such a stat accounts for all connections that are currently
established and not yet transitioned to close state.
Also fix bug in double increment of CurrentEstablished stat.
Fixes#1579
PiperOrigin-RevId: 290827365
CERT Advisory CA-96.21 III. Solution advises that devices drop packets which
could not have correctly arrived on the wire, such as receiving a packet where
the source IP address is owned by the device that sent it.
Fixes#1507
PiperOrigin-RevId: 290378240
The change to introduce worker goroutines can cause the endpoint
to transition to StateError and we should terminate the loop rather
than let the endpoint transition to a CLOSED state as we do
in case the endpoint enters TIME-WAIT/CLOSED. Moving to a closed
state would cause the actual error to not be propagated to
any read() calls etc.
PiperOrigin-RevId: 289923568
All inbound segments for connections in ESTABLISHED state are delivered to the
endpoint's queue but for every segment delivered we also queue the endpoint for
processing to a selected processor. This ensures that when there are a large
number of connections in ESTABLISHED state the inbound packets are all handled
by a small number of goroutines and significantly reduces the amount of work the
goscheduler has to perform.
We let connections in other states follow the current path where the
endpoint's goroutine directly handles the segments.
Updates #231
PiperOrigin-RevId: 289728325
* Rename syncutil to sync.
* Add aliases to sync types.
* Replace existing usage of standard library sync package.
This will make it easier to swap out synchronization primitives. For example,
this will allow us to use primitives from github.com/sasha-s/go-deadlock to
check for lock ordering violations.
Updates #1472
PiperOrigin-RevId: 289033387
Before, each of small read()'s that raises window either from zero
or above threshold of aMSS, would generate an ACK. In a classic
silly-window-syndrome scenario, we can imagine a pessimistic case
when small read()'s generate a stream of ACKs.
This PR fixes that, essentially treating window size < aMSS as zero.
We send ACK exactly in a moment when window increases to >= aMSS
or half of receive buffer size (whichever smaller).
When receiving data, netstack avoids sending spurious acks. When
user does recv() should netstack send ack telling the sender that
the window was increased? It depends. Before this patch, netstack
_will_ send the ack in the case when window was zero or window >>
scale was zero. Basically - when recv space increased from zero.
This is not working right with silly-window-avoidance on the sender
side. Some network stacks refuse to transmit segments, that will fill
the window but are below MSS. Before this patch, this confuses
netstack. On one hand if the window was like 3 bytes, netstack
will _not_ send ack if the window increases. On the other hand
sending party will refuse to transmit 3-byte packet.
This patch changes that, making netstack will send an ACK when
the available buffer size increases to or above 1*MSS. This will
inform other party buffer is large enough, and hopefully uncork it.
Signed-off-by: Marek Majkowski <marek@cloudflare.com>
Added the ability to get/set the IP_RECVTOS socket option on UDP endpoints. If
enabled, TOS from the incoming Network Header passed as ancillary data in the
ControlMessages.
Test:
* Added unit test to udp_test.go that tests getting/setting as well as
verifying that we receive expected TOS from incoming packet.
* Added a syscall test
PiperOrigin-RevId: 287029703
When listen(2) is called on an unbound socket, the socket is
automatically bound to a random free port with the local address
set to INADDR_ANY.
PiperOrigin-RevId: 286305906
The implementation follows the linux behavior where specifying
a TCP_USER_TIMEOUT will cause the resend timer to honor the
user specified timeout rather than the default rto based timeout.
Further it alters when connections are timedout due to keepalive
failures. It does not alter the behavior of when keepalives are
sent. This is as per the linux behavior.
PiperOrigin-RevId: 285099795
This change marks the socket as ESTABLISHED and creates the receiver and sender
the moment we send the final ACK in case of an active TCP handshake or when we
receive the final ACK for a passive TCP handshake. Before this change there was
a short window in which an ACK can be received and processed but the state on
the socket is not yet ESTABLISHED.
This can be seen in TestConnectBindToDevice which is flaky because sometimes
the socket is in SYN-SENT and not ESTABLISHED even though the other side has
already received the final ACK of the handshake.
PiperOrigin-RevId: 284277713
If the socket is bound to ANY and connected to a loopback address,
getsockname() has to return the loopback address. Without this fix,
getsockname() returns ANY.
PiperOrigin-RevId: 283647781
The code in rcv.consumeSegment incorrectly transitions to
CLOSED state from LAST-ACK before the final ACK for the FIN.
Further if receiving a segment changes a socket to a closed state
then we should not invoke the sender as the socket is now closed
and sending any segments is incorrect.
PiperOrigin-RevId: 283625300
This change does not introduce any new features, or modify existing ones.
This change tests handling TCP segments right away for connections that were
completed from a listening endpoint.
PiperOrigin-RevId: 282986457
As we move to CLOSE state from LAST-ACK or TIME-WAIT,
ensure that we re-match all in-flight segments to any
listening endpoint.
Also fix LISTEN state handling of any ACK segments as per RFC793.
Fixes#1153
PiperOrigin-RevId: 280703556
This change drops TCP packets with a non-unicast IP address as the source or
destination address as TCP is meant for communication between two endpoints.
Test: Make sure that if the source or destination address contains a non-unicast
address, no TCP packet is sent in response and the packet is dropped.
PiperOrigin-RevId: 280073731
* Basic tests for the SO_REUSEADDR and SO_REUSEPORT options.
* SO_REUSEADDR functional tests for TCP and UDP.
* SO_REUSEADDR and SO_REUSEPORT interaction tests for UDP.
* Stubbed support for UDP getsockopt(SO_REUSEADDR).
PiperOrigin-RevId: 280049265
This change adds explicit support for honoring the 2MSL timeout
for sockets in TIME_WAIT state. It also adds support for the
TCP_LINGER2 option that allows modification of the FIN_WAIT2
state timeout duration for a given socket.
It also adds an option to modify the Stack wide TIME_WAIT timeout
but this is only for testing. On Linux this is fixed at 60s.
Further, we also now correctly process RST's in CLOSE_WAIT and
close the socket similar to linux without moving it to error
state.
We also now handle SYN in ESTABLISHED state as per
RFC5961#section-4.1. Earlier we would just drop these SYNs.
Which can result in some tests that pass on linux to fail on
gVisor.
Netstack now honors TIME_WAIT correctly as well as handles the
following cases correctly.
- TCP RSTs in TIME_WAIT are ignored.
- A duplicate TCP FIN during TIME_WAIT extends the TIME_WAIT
and a dup ACK is sent in response to the FIN as the dup FIN
indicates potential loss of the original final ACK.
- An out of order segment during TIME_WAIT generates a dup ACK.
- A new SYN w/ a sequence number > the highest sequence number
in the previous connection closes the TIME_WAIT early and
opens a new connection.
Further to make the SYN case work correctly the ISN (Initial
Sequence Number) generation for Netstack has been updated to
be as per RFC. Its not a pure random number anymore and follows
the recommendation in https://tools.ietf.org/html/rfc6528#page-3.
The current hash used is not a cryptographically secure hash
function. A separate change will update the hash function used
to Siphash similar to what is used in Linux.
PiperOrigin-RevId: 279106406
Adin Scannell
Eyal Soha
Ian Gudger
Ghanan Gowripalan
Bhasker Hariharan
Ting-Yu Wang
Mithun Iyer
gVisor bot
Tamir Duberstein
Kevin Krakauer
Bert Muthalaly
Marek Majkowski
Ryan Heacock
Andrei Vagin