| /* (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; |
| } |
| |
| /*! @} */ |