The simple fact that Witness records might show up in the log might
break logexpect commands. There's no reason why we'd want to expect
Witness records since their purpose is to be checked after the test
finishes.

This change introduces a top-level make witness target that builds a dot
graph and if graphviz is available, an SVG file as well. A shell script
replaces the previous python script that no longer works. Instead of
fixing witness.py, which is probably trivial, the shell script does an
intermediate pass and programmatically looks for cycles using tsort(1).

Checking lock dependencies becomes actionable in a CI context.

The script also takes explicit test directories on purpose, to have the
ability to aggregate test results from multiple executions. For example
when the test suite is run on various operating systems or with varying
privileges to cover feature-conditional tests.

Conflicts:
	tools/witness.sh

The 6.0 branch does not contain the dT change in the vtc output, so
columns collected by the shell script were off by one.

Performing the conversion on the stack could lead to a buffer too small
to store the string representation of the IP address. There is no test
case because the error handling is output to stderr.

Refs #3765

Conflicts:
	bin/varnishd/cache/cache_vrt.c

Conflicts:
	bin/varnishd/http2/cache_http2_session.c

This to silence errors on OSX where apparently int64_t isn't type
equivalent to intmax_t, causing printf-errors when using %jd.

Fixes: #3699

There's no way to probe the current push status or maximum frame size.

Except that the old default value replaces the maximum one. Aligning
with the literal maximum value for the underlying HTTP/2 setting breaks
32bit builds because the byte tweaks take a detour via ssize_t. When it
casts to uintmax_t the MSB is propagated all the way, triggering the
following error at build time:

> 4294967295b is too large for this architecture.

Instead of fighting a tweak that is clearly wrong, grant h2 clients a
maximum of 2GB of uncompressed headers (instead of 4GB) that will never
happen, because h2 is overall much wronger.

Conflicts:
	include/tbl/params.h

This parameter has a new role that consists in interrupting connections
when decoding an HPACK block leads to a header list so large that the
client must be stopped.

By default, too large is 150% of http_req_size.

Conflicts:
	include/tbl/params.h

Since http_req_size was already established for this purpose, and is
now enforced for h2 traffic, it should naturally become the basis for
the MAX_HEADER_LIST_SIZE setting in the initial SETTINGS frame sent
to clients.

The h2_max_header_list_size parameter will grow a new purpose.

Conflicts:
	bin/varnishtest/tests/t02000.vtc
	bin/varnishtest/tests/t02005.vtc
	include/tbl/params.h

With the exception of h2_max_header_list_size that is not advertised as
such despite being ent as part of the initial SETTINGS frame. The same
parameter also sees its default and maximum values updated to 2^32-1.

This is based on this sentence from rfc9113:

> The initial value of this setting is unlimited.

This aligns the h2_max_header_list_size parameter with the values set in
h2_settings.h for MAX_HEADER_LIST_SIZE.

Conflicts:
	include/tbl/params.h

For the sole purpose of having these limits tested in a single place.

Refs #3709
Refs #3892

Conflicts:
	bin/varnishd/http2/cache_http2_hpack.c

Refs #3709

It does a first pass on header names and values, and only logs errors,
so the signature is updated accordingly and the call site is moved into
h2h_addhdr().

Conflicts:
	bin/varnishd/http2/cache_http2_hpack.c

A warning triggered despite the presence of FALL_THROUGH.

Better diff with the --ignore-all-space option.

It became explicit in rfc9113:

> The same pseudo-header field name MUST NOT appear more than once in a
> field block.

While at it, the duplicate pseudo-header error can be consolidated in a
single location instead of adding one more branch.

Instead of passing both a decoder and individual decoder fields, the
signature for h2h_addhdr() changed to only take the decoder. The order
of parameters is destination first, then the source following the
calling conventon of functions like memcpy().

Internally the function is reorganized with a bunch of txt variables to
keep track of the header being added, its name and value. In addition to
clarity, this also helps improve safety and correctness.

For example the :authority pseudo-header name is erased in place to turn
it into a regular host header, but having a dedicated txt for the header
name allows its preservation.

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

This requirement was dropped in the updated rfc 9113.

Fixes: #3911

Conflicts:
	bin/varnishd/http2/cache_http2_proto.c

I accidentally committed an earlier, wrong version. o/ Dridi

Ref #3407

https://github.com/varnishcache/varnish-cache/pull/3407#issuecomment-696146625

Conflicts:
	include/vct.h

The previous commit introduces more than just this macro and was skipped
on purpose.

Conflicts:
	include/vdef.h

The extra space before the colon looked uncanny. The rest is just code
indentation improvements.

Better diff with the --ignore-all-space --word-diff options.

There is room for further improvement in the dynamic between HPACK and
the HTTP/2 session, but this will serve as the first step.

Conflicts:
	include/tbl/h2_error.h

There are other components than the cache process that could benefit
from it, in particular libvcc. The relationship with vas.h is somewhat
unfortunate but that also centralize the Tcheck() logic in pdiff() and
doesn't actually require vas.h unless the macros are used, in which
case it's almost guaranteed that the calling code already included
vas.h in the first place.

The benefits should outweigh the drawbacks.

Conflicts:
	bin/varnishd/cache/cache.h
	bin/varnishtest/vtc_http.c

This way it can be used almost anywhere in the code base and out of tree,
not just in the cache process. The function was slightly polished after
prior discussions with phk and slink.

Conflicts:
	include/vas.h