/* * (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. * */ #include "config.h" #include #include #include #include #include #include #include /*! \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 ยง3.2.2.115 */ 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; } /*! Compare two GCR structs. * \param[in] gcr1 pointer to the GCR struct * \param[in] gcr2 pointer to the GCR struct * \returns true if GCRs are equal, false otherwise */ bool osmo_gcr_eq(const struct osmo_gcr_parsed *gcr1, const struct osmo_gcr_parsed *gcr2) { if (gcr1->net_len != gcr2->net_len) return false; if (gcr1->node != gcr2->node) return false; if (memcmp(gcr1->cr, gcr2->cr, 5) != 0) return false; if (memcmp(gcr1->net, gcr2->net, gcr2->net_len) != 0) return false; return true; }