Hippotat - Asinine IP Over HTTP program

Copyright 2017,2019-2022 Ian Jackson and contributors to Hippotat

The client and server are:

 GPLv3+

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program, in the file GPLv3.  If not,
    see <http://www.gnu.org/licenses/>.

On a Debian system, the GNU General Public License v3 can be found in
/usr/share/common-licenses/GPL-3


Formalities
-----------

The licence is generally indicated in each file with an SPDX
delcaration; as is conventional, this should be read as a licence
grant.

Contributions to Hippotat are accepted based on the git commit
Signed-off-by convention, by which the contributors' certify their
contributions according to the Developer Certificate of Origin version
1.1 - see the file DEVELOPER-CERTIFICATE.

If you create a new file please be sure to add an appropriate licence
header, probably something like this:
// Copyright 2017-2022 Ian Jackson and contributors to Hippotat
// SPDX-License-Identifier: AGPL-3.0-or-later
// There is NO WARRANTY.


OpenSSL Licence Exception
-------------------------

Additional permission under GNU GPL version 3 section 7
[LicenseRef-Hippotat-OpenSSL-Exception]:

    In addition, as a special exception, the copyright holders give
    permission to link the code of this program with the OpenSSL
    Library (or with modified versions of OpenSSL that use the same
    license as OpenSSL 1.1), and distribute linked combinations
    including the two.

    BUT this does NOT apply to version 3.0 or any later version of the
    OpenSSL library (nor to any modified versions thereof).  (We make
    this restriction because the exception is not needed with OpenSSL 3.)

    FURTHERMORE to take advantage of this exception you must obey the
    GNU Lesser General Public License (version 3, or, at your option,
    any later version) in all respects for all of the code used other
    than OpenSSL.

This additional permission is indicated in the source code with
the following SPDX licence declaration:
    SPDX-License-Identifier: GPL-3.0-or-later WITH LicenseRef-Hippotat-OpenSSL-Exception
(which is roughly but not exactly in accordance with the SPDX spec.)

If you modify a file, you may extend this exception to your version of
the file, but you are not obligated to do so. If you do not wish to do
so, delete the exception statement from your version, changing it to:
    SPDX-License-Identifier: GPL-3.0-or-later

The authors of Hippotat will probably withdrawn this exception in a
future versions of Hippotat, when OpenSSL 3.0 (which has a
GPLv3+-compatible licence) has become sufficiently widespread.  But
that will not affect already-released versions of hippotat.