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/* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
* 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, see <http://www.gnu.org/licenses/>.
*
*/
#include <stdio.h>
#include <stdint.h>
#include <osmocom/core/utils.h>
#include <osmocom/gsm/tlv.h>
/*! \addtogroup tlv
* @{
*/
/*! \file tlv_parser.c */
struct tlv_definition tvlv_att_def;
struct tlv_definition vtvlv_gan_att_def;
/*! \brief Dump pasred TLV structure to stdout */
int tlv_dump(struct tlv_parsed *dec)
{
int i;
for (i = 0; i <= 0xff; i++) {
if (!dec->lv[i].val)
continue;
printf("T=%02x L=%d\n", i, dec->lv[i].len);
}
return 0;
}
/*! \brief Parse a single TLV encoded IE
* \param[out] o_tag the tag of the IE that was found
* \param[out] o_len length of the IE that was found
* \param[out] o_val pointer to the data of the IE that was found
* \param[in] def structure defining the valid TLV tags / configurations
* \param[in] buf the input data buffer to be parsed
* \param[in] buf_len length of the input data buffer
* \returns number of bytes consumed by the TLV entry / IE parsed
*/
int tlv_parse_one(uint8_t *o_tag, uint16_t *o_len, const uint8_t **o_val,
const struct tlv_definition *def,
const uint8_t *buf, int buf_len)
{
uint8_t tag;
int len;
tag = *buf;
*o_tag = tag;
/* single octet TV IE */
if (def->def[tag & 0xf0].type == TLV_TYPE_SINGLE_TV) {
*o_tag = tag & 0xf0;
*o_val = buf;
*o_len = 1;
return 1;
}
/* FIXME: use tables for known IEI */
switch (def->def[tag].type) {
case TLV_TYPE_T:
/* GSM TS 04.07 11.2.4: Type 1 TV or Type 2 T */
*o_val = buf;
*o_len = 0;
len = 1;
break;
case TLV_TYPE_TV:
*o_val = buf+1;
*o_len = 1;
len = 2;
break;
case TLV_TYPE_FIXED:
*o_val = buf+1;
*o_len = def->def[tag].fixed_len;
len = def->def[tag].fixed_len + 1;
break;
case TLV_TYPE_TLV:
tlv: /* GSM TS 04.07 11.2.4: Type 4 TLV */
if (buf + 1 > buf + buf_len)
return -1;
*o_val = buf+2;
*o_len = *(buf+1);
len = *o_len + 2;
if (len > buf_len)
return -2;
break;
case TLV_TYPE_vTvLV_GAN: /* 44.318 / 11.1.4 */
/* FIXME: variable-length TAG! */
if (*(buf+1) & 0x80) {
/* like TL16Vbut without highest bit of len */
if (2 > buf_len)
return -1;
*o_val = buf+3;
*o_len = (*(buf+1) & 0x7F) << 8 | *(buf+2);
len = *o_len + 3;
if (len > buf_len)
return -2;
} else {
/* like TLV */
goto tlv;
}
break;
case TLV_TYPE_TvLV:
if (*(buf+1) & 0x80) {
/* like TLV, but without highest bit of len */
if (buf + 1 > buf + buf_len)
return -1;
*o_val = buf+2;
*o_len = *(buf+1) & 0x7f;
len = *o_len + 2;
if (len > buf_len)
return -2;
break;
}
/* like TL16V, fallthrough */
case TLV_TYPE_TL16V:
if (2 > buf_len)
return -1;
*o_val = buf+3;
*o_len = *(buf+1) << 8 | *(buf+2);
len = *o_len + 3;
if (len > buf_len)
return -2;
break;
default:
return -3;
}
return len;
}
/*! \brief Parse an entire buffer of TLV encoded Information Elements
* \param[out] dec caller-allocated pointer to \ref tlv_parsed
* \param[in] def structure defining the valid TLV tags / configurations
* \param[in] buf the input data buffer to be parsed
* \param[in] buf_len length of the input data buffer
* \param[in] lv_tag an initial LV tag at the start of the buffer
* \param[in] lv_tag2 a second initial LV tag following the \a lv_tag
* \returns number of bytes consumed by the TLV entry / IE parsed
*/
int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def,
const uint8_t *buf, int buf_len, uint8_t lv_tag,
uint8_t lv_tag2)
{
int ofs = 0, num_parsed = 0;
uint16_t len;
memset(dec, 0, sizeof(*dec));
if (lv_tag) {
if (ofs > buf_len)
return -1;
dec->lv[lv_tag].val = &buf[ofs+1];
dec->lv[lv_tag].len = buf[ofs];
len = dec->lv[lv_tag].len + 1;
if (ofs + len > buf_len)
return -2;
num_parsed++;
ofs += len;
}
if (lv_tag2) {
if (ofs > buf_len)
return -1;
dec->lv[lv_tag2].val = &buf[ofs+1];
dec->lv[lv_tag2].len = buf[ofs];
len = dec->lv[lv_tag2].len + 1;
if (ofs + len > buf_len)
return -2;
num_parsed++;
ofs += len;
}
while (ofs < buf_len) {
int rv;
uint8_t tag;
const uint8_t *val;
rv = tlv_parse_one(&tag, &len, &val, def,
&buf[ofs], buf_len-ofs);
if (rv < 0)
return rv;
dec->lv[tag].val = val;
dec->lv[tag].len = len;
ofs += rv;
num_parsed++;
}
//tlv_dump(dec);
return num_parsed;
}
/*! \brief take a master (src) tlvdev and fill up all empty slots in 'dst' */
void tlv_def_patch(struct tlv_definition *dst, const struct tlv_definition *src)
{
int i;
for (i = 0; i < ARRAY_SIZE(dst->def); i++) {
if (src->def[i].type == TLV_TYPE_NONE)
continue;
if (dst->def[i].type == TLV_TYPE_NONE)
dst->def[i] = src->def[i];
}
}
static __attribute__((constructor)) void on_dso_load_tlv(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(tvlv_att_def.def); i++)
tvlv_att_def.def[i].type = TLV_TYPE_TvLV;
for (i = 0; i < ARRAY_SIZE(vtvlv_gan_att_def.def); i++)
vtvlv_gan_att_def.def[i].type = TLV_TYPE_vTvLV_GAN;
}
/*! @} */
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