VILLASnode/lib/io/webmsg.c

/** Websocket message related functions.
 *
 * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
 * @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
 * @license GNU General Public License (version 3)
 *
 * VILLASnode
 *
 * 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
 * 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, see <http://www.gnu.org/licenses/>.
 *********************************************************************************/

#ifdef __MACH__
  #include "compat.h"
#elif defined(__linux__)
  #include <endian.h>
#endif

#include "sample.h"
#include "plugin.h"
#include "formats/webmsg.h"
#include "formats/webmsg_format.h"

void webmsg_ntoh(struct webmsg *m)
{
	webmsg_hdr_ntoh(m);

	for (int i = 0; i < m->length; i++)
		m->data[i].i = le32toh(m->data[i].i);
}

void webmsg_hton(struct webmsg *m)
{
	for (int i = 0; i < m->length; i++)
		m->data[i].i = htole32(m->data[i].i);

	webmsg_hdr_hton(m);
}

void webmsg_hdr_hton(struct webmsg *m)
{
	m->length   = htole16(m->length);
	m->sequence = htole32(m->sequence);
	m->ts.sec   = htole32(m->ts.sec);
	m->ts.nsec  = htole32(m->ts.nsec);
}

void webmsg_hdr_ntoh(struct webmsg *m)
{
	m->length   = le16toh(m->length);
	m->sequence = le32toh(m->sequence);
	m->ts.sec   = le32toh(m->ts.sec);
	m->ts.nsec  = le32toh(m->ts.nsec);
}

int webmsg_verify(struct webmsg *m)
{
	if      (m->version != WEBMSG_VERSION)
		return -1;
	else if (m->type    != WEBMSG_TYPE_DATA)
		return -2;
	else if (m->rsvd1 != 0)
		return -3;
	else
		return 0;
}

int webmsg_to_sample(struct webmsg *msg, struct sample *smp)
{
	int ret;

	webmsg_ntoh(msg);

	ret = webmsg_verify(msg);
	if (ret)
		return -1;

	smp->length = MIN(msg->length, smp->capacity);
	smp->sequence = msg->sequence;
	smp->id = msg->id;
	smp->ts.origin = WEBMSG_TS(msg);
	smp->ts.received.tv_sec  = -1;
	smp->ts.received.tv_nsec = -1;

	memcpy(smp->data, msg->data, SAMPLE_DATA_LEN(smp->length));

	return 0;
}

int webmsg_from_sample(struct webmsg *msg, struct sample *smp)
{
	*msg = WEBMSG_INIT(smp->length, smp->sequence);

	msg->id = smp->id;
	msg->ts.sec  = smp->ts.origin.tv_sec;
	msg->ts.nsec = smp->ts.origin.tv_nsec;

	memcpy(msg->data, smp->data, WEBMSG_DATA_LEN(smp->length));

	msg_hton(msg);

	return 0;
}

size_t io_format_webmsg_length(struct sample *smps[], size_t cnt)
{
	size_t sz = 0;

	for (int i = 0; i < cnt; i++)
		sz += WEBMSG_LEN(smps[i]->length);

	return sz;
}

size_t io_format_webmsg_sprint(char *buf, size_t len, struct sample *smps[], size_t cnt, int flags)
{
	int ret, i = 0;
	char *ptr = buf;

	struct webmsg *msg = (struct webmsg *) ptr;
	struct sample *smp = smps[i];

	while (ptr < buf + len && i < cnt) {
		ret = webmsg_from_sample(msg, smp);
		if (ret)
			return ret;

		ptr += WEBMSG_LEN(smp->length);

		msg = (struct webmsg *) ptr;
		smp = smps[++i];
	}

	return ptr - buf;
}

size_t io_format_webmsg_sscan(char *buf, size_t len, struct sample *smps[], size_t cnt, int *flags)
{
	int ret, i = 0;
	char *ptr = buf;

	struct webmsg *msg = (struct webmsg *) ptr;
	struct sample *smp = smps[i];

	while (ptr < buf + len && i < cnt) {
		ret = webmsg_to_sample(msg, smp);
		if (ret)
			return ret;

		ptr += WEBMSG_LEN(smp->length);

		msg = (struct webmsg *) ptr;
		smp = smps[++i];
	}

	return i;
}

static struct plugin p = {
	.name = "webmsg",
	.description = "VILLAS binary format for websockets",
	.type = PLUGIN_TYPE_FORMAT,
	.format = {
		.length	= io_format_webmsg_length,
		.sprint	= io_format_webmsg_sprint,
		.sscan	= io_format_webmsg_sscan,
		.flags	= IO_FORMAT_BINARY,
		.size = 0
	},
};

REGISTER_PLUGIN(&p);