mirror of https://gerrit.osmocom.org/libosmocore
115 lines
3.1 KiB
C
115 lines
3.1 KiB
C
/*
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* (C) 2018 by sysmocom - s.f.m.c. GmbH
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* All Rights Reserved
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <osmocom/gsm/protocol/gsm_08_08.h>
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#include <osmocom/gsm/gsm29205.h>
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#include <osmocom/gsm/gsm0808.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/gsm/tlv.h>
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#include <errno.h>
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/*! \addtogroup gsm29205
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* @{
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* \file gsm29205.c
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* Functions related to 3GPP TS 29.205, primarily message generation/encoding.
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*/
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/*! Create Global Call Reference.
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* \param[out] msg Message Buffer for appending IE
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* \param[in] g Global Call Reference, 3GPP TS 29.205 Table B 2.1.9.1
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* \returns number of bytes added to \a msg */
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uint8_t osmo_enc_gcr(struct msgb *msg, const struct osmo_gcr_parsed *g)
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{
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uint8_t buf[2];
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if (!g)
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return 0;
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if (g->net_len < 3 || g->net_len > 5)
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return 0;
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msgb_lv_put(msg, g->net_len, g->net);
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osmo_store16be(g->node, &buf);
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msgb_lv_put(msg, 2, buf);
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msgb_lv_put(msg, 5, g->cr);
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/* Length: LV(Net) + LV(Node) + LV(CRef) - see 3GPP TS §3.2.2.115 */
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return (g->net_len + 1) + (2 + 1) + (5 + 1);
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}
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/*! Decode Global Call Reference, 3GPP TS 29.205 Table B 2.1.9.1.
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* \param[out] gcr Caller-provided memory to store Global Call Reference
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* \param[in] elem IE value to be decoded
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* \param[in] len Length of \a elem in bytes
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* \returns number of bytes parsed; negative on error */
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int osmo_dec_gcr(struct osmo_gcr_parsed *gcr, const uint8_t *elem, uint8_t len)
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{
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uint16_t parsed = 1; /* account for length byte right away */
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if (len < 13)
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return -EBADMSG;
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gcr->net_len = elem[0];
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if (gcr->net_len < 3 || gcr->net_len > 5)
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return -EINVAL;
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memcpy(gcr->net, elem + parsed, gcr->net_len);
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/* +1 for ignored Node ID length field */
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parsed += (gcr->net_len + 1);
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gcr->node = osmo_load16be(elem + parsed);
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parsed += 2;
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if (elem[parsed] != 5) /* see Table B 2.1.9.2 */
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return -ENOENT;
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parsed++;
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memcpy(gcr->cr, elem + parsed, 5);
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return parsed + 5;
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}
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/*! Compare two GCR structs.
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* \param[in] gcr1 pointer to the GCR struct
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* \param[in] gcr2 pointer to the GCR struct
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* \returns true if GCRs are equal, false otherwise */
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bool osmo_gcr_eq(const struct osmo_gcr_parsed *gcr1, const struct osmo_gcr_parsed *gcr2)
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{
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if (gcr1->net_len != gcr2->net_len)
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return false;
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if (gcr1->node != gcr2->node)
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return false;
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if (memcmp(gcr1->cr, gcr2->cr, 5) != 0)
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return false;
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if (memcmp(gcr1->net, gcr2->net, gcr2->net_len) != 0)
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return false;
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return true;
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}
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