serval-dna/overlay_mdp_echo.c
Andrew Bettison 71cbe86566 Switch to feature-driven linking
This introduces a new way of linking Serval executables and dynamic
libraries from static libraries like libservald.a -- called
"feature-driven" linking.

The Makefile now links servald and serval-tests from libservald.a,
rather than from an explicit list of object (.o) files.  Thanks to the
section-based method for registering functions such as HTTP handlers,
CLI commands and MDP handlers, these object files had become
"stand-alone" and hence were no longer included in the link because
there was no unresolved reference that required them to be linked in.

The new "feature.h" provides the DECLARE_FEATURE(name) macro that each
stand-alone source file uses to declare the named feature(s) it
provides.  Each executable can call the USE_FEATURE(name) macro in any
of its explicitly-linked source files to cause the corresponding
object(s) to be included in the link, eg, servald_features.c.

The DEFINE_BINDING() macro has been extended so that every individual
MDP binding is given a feature name based on its port number macro, eg,
"mdp_binding_MDP_PORT_ECHO".

Some features have been factored into their own separate source files so
they can be omitted or included in a build independently of each other:
- the MDP bindings for MDP_PORT_DNALOOKUP, MDP_PORT_ECHO,
  MDP_PORT_TRACE, MDP_PORT_KEYMAPREQUEST, MDP_PORT_RHIZOME_xxx,
  MDP_PORT_PROBE, MDP_PORT_STUN, MDP_PORT_STUNREQ
- the CLI "log" and "echo" commands
- the CLI "rhizome direct" command

The JNI source files are only compiled if the <jni.h> header is present,
otherwise they are omitted from libservald.so.
2016-10-19 09:33:01 +10:30

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1.4 KiB
C

/*
Serval DNA MDP echo service
Copyright (C) 2016 Flinders University
Copyright (C) 2012-2015 Serval Project Inc.
Copyright (C) 2012 Paul Gardner-Stephen
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 2
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; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "mdp_client.h"
#include "overlay_packet.h"
#include "fdqueue.h"
DEFINE_BINDING(MDP_PORT_ECHO, overlay_mdp_service_echo);
static int overlay_mdp_service_echo(struct internal_mdp_header *header, struct overlay_buffer *payload)
{
IN();
if (header->source_port == MDP_PORT_ECHO)
RETURN(WHY("Prevented infinite echo loop"));
struct internal_mdp_header response_header;
bzero(&response_header, sizeof response_header);
mdp_init_response(header, &response_header);
// keep all defaults
RETURN(overlay_send_frame(&response_header, payload));
OUT();
}