Conflicts:
	doc/changes.rst

Conflicts:
	doc/changes.rst

Suppose the following happens:

vbp_task() finishes with vt->running = 0 and a heap insert. The
vbp_cond is signaled under the lock, but now instead of vbp_thread()
waking up first, VBP_Remove() gets the lock and reaches
assert(vt->heap_idx == VBH_NOIDX) before the racing vbp_thread()
deleted the heap.

This is unlikely to happen with static backends, because for those,
the probe is stopped via the vcl temperature before they get removed.

Fixes https://github.com/nigoroll/libvmod-dynamic/issues/100

Ref: 582ded6a

Fixes #3958

The VSB bits in here come with a very significant performance penalty
for H2 request body processing.

This requirement was dropped in the updated rfc 9113.

Fixes: #3911

with uds abstract sockets, sun_path should start with a NULL character followed
by the socket's name. The name is not considered to be NULL terminated and can
contain NULL bytes which have no special meaning. socklen is used to determine
the length of name and must be set to the length of the struct sockaddr_un up to
the last character of name, otherwise the 108 characters of sun_path will be
treated as the name of the socket, including NULL bytes.

Adds coverage for tab characters at start/end of field value.

Regarding the "fo o" " bar" header, it cumulates an error in the name
and another in the value, but only one of them will trigger the expected
PROTOCOL_ERROR. Only the invalid "fo o" is checked now, and the other
error is part of the new coverage.
Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

Control characters will be caught by vct_ishdrval() anyways, but this
condition would also reject allowed obs-text non-ASCII characters.
Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

Fixes #3952

Conflicts:
	vmod/vmod_h2.c

we can not make the parameter const because API.

(sorry)

as agreed on IRC.

Conflicts:
	vmod/automake_boilerplate_h2.am
	vmod/vmod_h2.vcc

This will allow per-session adjustments and also significantly
lower the risk of inconsistent calculations in the rate limit
code during parameter changes.

Ref #3996

Noticed while porting #3998 to the 6.0 branch with a varnishtest more
sensitive to timing.

With #3998 we need to ensure streams are not going to skip vcl_recv if
reset faster than reaching this step for the request task.

The alternative to prevent the vcl_req_reset feature from interfering
is to simply disable it.

The error check is not performed in a critical section to avoid
contention, at the risk of not seeing the error until the next
transport poll.

Once a client is reportedly gone, processing its VCL task(s) is just a
waste of resources. The execution of client-facing VCL is intercepted
and an artificial return(fail) is returned in that scenario.

Thanks to the introduction of the universal return(fail) proper error
handling and resource tear down is already in place, which makes this
change safe modulus unknown bugs. This adds a circuit breaker anywhere
in the client state machine where there is VCL execution.

A new Reset time stamp is logged to convey when a task does not complete
because the client is gone. This is a good complement to the walk away
feature and its original circuit breaker for the waiting list, but this
has not been integrated yet.

While the request is technically failed, it won't increase the vcl_fail
counter, and a new req_reset counter is incremented. This new behavior
is guarded by a new vcl_req_reset feature flag, enabled by default.

Refs #3835
Refs 61a15cbf
Refs e5efc2c8
Refs ba54dc91
Refs 6f50a00f
Refs b8816994

Conflicts:
	include/tbl/feature_bits.h

The goal is for top-level transports to report whether the client is
still present or not.

It was particularly hard to follow once we reach client c3.

Only RST frames received earlier than this duration will be considered
rapid.