| #include <stdio.h> |
| #include <openbsc/tlv.h> |
| #include <openbsc/gsm_data.h> |
| |
| struct tlv_definition tvlv_att_def; |
| |
| 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; |
| } |
| |
| /* o_tag: output: tag found |
| * o_len: output: length of the data |
| * o_val: output: pointer to the data |
| * def: input: a structure defining the valid TLV tags / configurations |
| * buf: input: the input data buffer to be parsed |
| * buf_len: input: the length of the input data buffer |
| * |
| * Also, returns the number of bytes consumed by the TLV entry |
| */ |
| int tlv_parse_one(u_int8_t *o_tag, u_int16_t *o_len, const u_int8_t **o_val, |
| const struct tlv_definition *def, |
| const u_int8_t *buf, int buf_len) |
| { |
| u_int8_t tag; |
| int len; |
| |
| tag = *buf; |
| *o_tag = tag; |
| |
| /* FIXME: use tables for knwon 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: |
| /* 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_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; |
| } |
| |
| /* dec: output: a caller-allocated pointer to a struct tlv_parsed, |
| * def: input: a structure defining the valid TLV tags / configurations |
| * buf: input: the input data buffer to be parsed |
| * buf_len: input: the length of the input data buffer |
| * lv_tag: input: an initial LV tag at the start of the buffer |
| * lv_tag2: input: a second initial LV tag following lv_tag |
| */ |
| int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def, |
| const u_int8_t *buf, int buf_len, u_int8_t lv_tag, |
| u_int8_t lv_tag2) |
| { |
| int ofs = 0, num_parsed = 0; |
| u_int16_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; |
| u_int8_t tag; |
| const u_int8_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; |
| } |
| |
| 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; |
| } |