#-
# Copyright 2023 UPLEX - Nils Goroll Systemoptimierung
# All rights reserved.
#
# Author: Nils Goroll <nils.goroll@uplex.de>
#
# SPDX-License-Identifier: BSD-2-Clause
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

$ABI strict
$Module h2 3 "Module to control the built-in HTTP2 transport"

DESCRIPTION
===========

This VMOD contains functions to control the HTTP2 transport built into
Varnish-Cache.

$Function BOOL is()
$Restrict client

Returns true when called on a session handled by the built-in HTTP2 transport.

$Function DURATION rapid_reset([DURATION threshold])
$Restrict client

Get and optionally set the ``h2_rapid_reset`` parameter (See
:ref:`varnishd(1)`) for this HTTP2 session only.

Returns -1 when used outside the HTTP2 transport. Otherwise returns
the previous value.

If the call leads to a change in the rate limit parameters, the
current budget as retuned by
`h2.rapid_reset_budget()`_ is reset.

$Function INT rapid_reset_limit([INT number])
$Restrict client

Get and optionally set the ``h2_rapid_reset_limit`` parameter (See
:ref:`varnishd(1)`) for this HTTP2 session only.

Returns -1 when used outside the HTTP2 transport. Otherwise returns
the previous value.

If the call leads to a change in the rate limit parameters, the
current budget as retuned by
`h2.rapid_reset_budget()`_ is reset.

$Function DURATION rapid_reset_period([DURATION duration])
$Restrict client

Get and optionally set the ``h2_rapid_reset_period`` parameter (See
:ref:`varnishd(1)`) for this HTTP2 session only.

Returns -1 when used outside the HTTP2 transport. Otherwise returns
the previous value.

If the call leads to a change in the rate limit parameters, the
current budget as retuned by
`h2.rapid_reset_budget()`_ is reset.

$Function REAL rapid_reset_budget()
$Restrict client

Return how many RST frames classified as "rapid" the client is still
allowed to send before the session is going to be closed.

SEE ALSO
========

* :ref:`varnishd(1)`
* :ref:`vsl(7)`
