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-rw-r--r--libosmocore/src/tlv_parser.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/libosmocore/src/tlv_parser.c b/libosmocore/src/tlv_parser.c
new file mode 100644
index 000000000..407e57aa2
--- /dev/null
+++ b/libosmocore/src/tlv_parser.c
@@ -0,0 +1,171 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <osmocore/utils.h>
+#include <osmocore/tlv.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(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;
+}