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/*
* (C) 2018 by sysmocom - s.f.m.c. GmbH
* All Rights Reserved
*
* SPDX-License-Identifier: GPL-2.0+
*
* 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 <osmocom/gsm/protocol/gsm_08_08.h>
#include <osmocom/gsm/gsm29205.h>
#include <osmocom/gsm/gsm0808.h>
#include <osmocom/core/msgb.h>
#include <osmocom/gsm/tlv.h>
#include <errno.h>
/*! \addtogroup gsm29205
* @{
* \file gsm29205.c
* Functions related to 3GPP TS 29.205, primarily message generation/encoding.
*/
/*! Create Global Call Reference.
* \param[out] msg Message Buffer for appending IE
* \param[in] g Global Call Reference, 3GPP TS 29.205 Table B 2.1.9.1
* \returns number of bytes added to \a msg */
uint8_t osmo_enc_gcr(struct msgb *msg, const struct osmo_gcr_parsed *g)
{
uint8_t buf[2];
if (!g)
return 0;
if (g->net_len < 3 || g->net_len > 5)
return 0;
msgb_lv_put(msg, g->net_len, g->net);
osmo_store16be(g->node, &buf);
msgb_lv_put(msg, 2, buf);
msgb_lv_put(msg, 5, g->cr);
/* Length: LV(Net) + LV(Node) + LV(CRef) - see 3GPP TS §3.2.2.115 */
return (g->net_len + 1) + (2 + 1) + (5 + 1);
}
/*! Decode Global Call Reference, 3GPP TS 29.205 Table B 2.1.9.1.
* \param[out] gcr Caller-provided memory to store Global Call Reference
* \param[in] elem IE value to be decoded
* \param[in] len Length of \a elem in bytes
* \returns number of bytes parsed; negative on error */
int osmo_dec_gcr(struct osmo_gcr_parsed *gcr, const uint8_t *elem, uint8_t len)
{
uint16_t parsed = 1; /* account for length byte right away */
if (len < 13)
return -EBADMSG;
gcr->net_len = elem[0];
if (gcr->net_len < 3 || gcr->net_len > 5)
return -EINVAL;
memcpy(gcr->net, elem + parsed, gcr->net_len);
/* +1 for ignored Node ID length field */
parsed += (gcr->net_len + 1);
gcr->node = osmo_load16be(elem + parsed);
parsed += 2;
if (elem[parsed] != 5) /* see Table B 2.1.9.2 */
return -ENOENT;
parsed++;
memcpy(gcr->cr, elem + parsed, 5);
return parsed + 5;
}
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