From ec8b4501c7b0bfb286db7789635168d1b84f9105 Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Sat, 20 Feb 2010 20:34:29 +0100 Subject: intial checkin of the libosmocore project --- src/tlv_parser.c | 171 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 171 insertions(+) create mode 100644 src/tlv_parser.c (limited to 'src/tlv_parser.c') diff --git a/src/tlv_parser.c b/src/tlv_parser.c new file mode 100644 index 00000000..407e57aa --- /dev/null +++ b/src/tlv_parser.c @@ -0,0 +1,171 @@ +#include +#include +#include +#include + +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(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; + + /* 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 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; +} + +/* 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; +} -- cgit v1.2.3