This validates that struct fields if annotated with "// checklocks:mu" where
"mu" is a mutex field in the same struct then access to the field is only
done with "mu" locked.
All types that are guarded by a mutex must be annotated with
// +checklocks:<mutex field name>
For more details please refer to README.md.
PiperOrigin-RevId: 360729328
There is a short race where in Write an endpoint can transition from writable
to non-writable state due to say an incoming RST during the time we release
the endpoint lock and reacquire after copying the payload. In such a case
if the write happens to be a zero sized write we end up trying to call
sendData() even though nothing was queued.
This can panic when trying to enable/disable TCP timers if the endpoint had
already transitioned to a CLOSED/ERROR state due to the incoming RST as we
cleanup timers when the protocol goroutine terminates.
Sadly the race window is small enough that my attempts at reproducing the panic
in a syscall test has not been successful.
PiperOrigin-RevId: 359887905
Use maybeSendSegment while sending segments in RACK recovery which checks if
the receiver has space and splits the segments when the segment size is
greater than MSS.
PiperOrigin-RevId: 359641097
Prevents the following deadlock:
- Raw packet is sent via e.Write(), which read locks e.mu
- Connect() is called, blocking on write locking e.mu
- The packet is routed to loopback and back to e.HandlePacket(), which read
locks e.mu
Per the atomic.RWMutex documentation, this deadlocks:
"If a goroutine holds a RWMutex for reading and another goroutine might call
Lock, no goroutine should expect to be able to acquire a read lock until the
initial read lock is released. In particular, this prohibits recursive read
locking. This is to ensure that the lock eventually becomes available; a blocked
Lock call excludes new readers from acquiring the lock."
Also, release eps.mu earlier in deliverRawPacket.
PiperOrigin-RevId: 359600926
Entry check:
- Earlier implementation was preventing us from entering recovery even if
SND.UNA is lost but dupAckCount is still below threshold. Fixed that.
- We should only enter recovery when at least one more byte of data beyond the
highest byte that was outstanding when fast retransmit was last entered is
acked. Added that check.
Exit check:
- Earlier we were checking if SEG.ACK is in range [SND.UNA, SND.NXT]. The
intention was to check if any unacknowledged data was ACKed. Note that
(SEG.ACK - 1) is actually the sequence number which was ACKed. So we were
incorrectly including (SND.UNA - 1) in the range. Fixed the check to now be
(SEG.ACK - 1) in range [SND.UNA, SND.NXT).
Additionally, moved a RACK specific test to the rack tests file.
Added tests for the changes I made.
PiperOrigin-RevId: 357091322
TestRACKWithDuplicateACK is flaky as the reorder window can expire before
receiving three duplicate ACKs which will result in sending the first
unacknowledged segment twice: when reorder timer expired and again after
receiving the third duplicate ACK.
This CL will fix this behavior and will not resend the segment again if it was
already re-transmittted when reorder timer expired.
Update the TestRACKWithDuplicateACK to test that the first segment is
considered as lost and is re-transmitted.
PiperOrigin-RevId: 356855168
The limits for snd/rcv buffers for unix domain socket is controlled by the
following sysctls on linux
- net.core.rmem_default
- net.core.rmem_max
- net.core.wmem_default
- net.core.wmem_max
Today in gVisor we do not expose these sysctls but we do support setting the
equivalent in netstack via stack.Options() method. But AF_UNIX sockets in gVisor
can be used without netstack, with hostinet or even without any networking stack
at all. Which means ideally these sysctls need to live as globals in gVisor.
But rather than make this a big change for now we hardcode the limits in the
AF_UNIX implementation itself (which in itself is better than where we were
before) where it SO_SNDBUF was hardcoded to 16KiB. Further we bump the initial
limit to a default value of 208 KiB to match linux from the paltry 16 KiB we use
today.
Updates #5132
PiperOrigin-RevId: 356665498
We previously return EINVAL when connecting to port 0, however this is not the
observed behavior on Linux. One of the observable effects after connecting to
port 0 on Linux is that getpeername() will fail with ENOTCONN.
PiperOrigin-RevId: 356413451
Rename HandleNDupAcks() to HandleLossDetected() as it will enter this when
is detected after:
- reorder window expires and TLP (in case of RACK)
- dupAckCount >= 3
PiperOrigin-RevId: 355237858
Netstack today will send dupACK's with no rate limit for incoming out of
window segments. This can result in ACK loops for example if a TCP socket
connects to itself (actually permitted by TCP). Where the ACK sent in
response to packets being out of order itself gets considered as an out
of window segment resulting in another ACK being generated.
PiperOrigin-RevId: 355206877
...to remove the need for the transport layer to deduce the type of
error it received.
Rename HandleControlPacket to HandleError as HandleControlPacket only
handles errors.
tcpip.SockError now holds a tcpip.SockErrorCause interface that
different errors can implement.
PiperOrigin-RevId: 354994306
The network endpoint should not need to have logic to handle different
kinds of neighbor tables. Network endpoints can let the NIC know about
differnt neighbor discovery messages and let the NIC decide which table
to update.
This allows us to remove the LinkAddressCache interface.
PiperOrigin-RevId: 354812584
After receiving an ACK(cumulative or selective), RACK will update the reorder
window which is used as a settling time before marking the packet as lost.
This change will add an init function to initialize the variables in RACK and
also store the reference to sender in rackControl.
The reorder window is calculated as per rfc:
https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.2 Step 4.
PiperOrigin-RevId: 354453528
Previously, sending on an unconnected UDP socket would ignore the
SO_BINDTODEVICE option. Send on the configured interface when an UDP socket
is bound to an interface through setsockop SO_BINDTODEVICE.
Add packetimpact tests exercising UDP reads and writes with every combination
of bound/unbound, broadcast/multicast/unicast destination, and bound/not-bound
to device.
PiperOrigin-RevId: 354299670
As per RFC 4861 section 7.3.1,
A neighbor is considered reachable if the node has recently received
a confirmation that packets sent recently to the neighbor were
received by its IP layer. Positive confirmation can be gathered in
two ways: hints from upper-layer protocols that indicate a connection
is making "forward progress", or receipt of a Neighbor Advertisement
message that is a response to a Neighbor Solicitation message.
This change adds support for TCP to let the IP/link layers know that a
neighbor is reachable.
Test: integration_test.TestTCPConfirmNeighborReachability
PiperOrigin-RevId: 354222833
This CL adds support for the following fields:
- RTT, RTTVar, RTO
- send congestion window (sndCwnd) and send slow start threshold (sndSsthresh)
- congestion control state(CaState)
- ReorderSeen
PiperOrigin-RevId: 354195361
- This CL will initialize the function handler used for getting the send
buffer size limits during endpoint creation and does not require the caller of
SetSendBufferSize(..) to know the endpoint type(tcp/udp/..)
PiperOrigin-RevId: 353992634
connect() can be invoked multiple times on UDP/RAW sockets and in such
a case we should release the cached route from the previous connect.
Fixes#5359
PiperOrigin-RevId: 353919891
gVisor bot
Bhasker Hariharan
Andrei Vagin
Tamir Duberstein
Nayana Bidari
Kevin Krakauer
Ayush Ranjan
Zeling Feng
Ghanan Gowripalan
Marina Ciocea