[TLV] extend TLV parser with support for TvLV
Tag-variableLength-Value is an encoding scheme used in the GPRS NS
and BSSGP protocols, where the length value can be 8 or 16 bits,
depending on actual demand.
diff --git a/openbsc/include/openbsc/tlv.h b/openbsc/include/openbsc/tlv.h
index ae88e6e..6da4fb1 100644
--- a/openbsc/include/openbsc/tlv.h
+++ b/openbsc/include/openbsc/tlv.h
@@ -6,11 +6,33 @@
#include <openbsc/msgb.h>
+/* Terminology / wording
+ tag length value (in bits)
+
+ V - - 8
+ LV - 8 N * 8
+ TLV 8 8 N * 8
+ TL16V 8 16 N * 8
+ TLV16 8 8 N * 16
+ TvLV 8 8/16 N * 8
+
+*/
+
#define LV_GROSS_LEN(x) (x+1)
#define TLV_GROSS_LEN(x) (x+2)
#define TLV16_GROSS_LEN(x) ((2*x)+2)
#define TL16V_GROSS_LEN(x) (x+3)
+#define TVLV_MAX_ONEBYTE 0x7f
+
+static inline u_int16_t TVLV_GROSS_LEN(u_int16_t len)
+{
+ if (len <= TVLV_MAX_ONEBYTE)
+ return TLV_GROSS_LEN(len);
+ else
+ return TL16V_GROSS_LEN(len);
+}
+
/* TLV generation */
static inline u_int8_t *lv_put(u_int8_t *buf, u_int8_t len,
@@ -49,6 +71,20 @@
return buf + len*2;
}
+static inline u_int8_t *tvlv_put(u_int8_t *buf, u_int8_t tag, u_int16_t len,
+ const u_int8_t *val)
+{
+ u_int8_t *ret;
+
+ if (len <= TVLV_MAX_ONEBYTE) {
+ ret = tlv_put(buf, tag, len, val);
+ buf[1] |= 0x80;
+ } else
+ ret = tl16v_put(buf, tag, len, val);
+
+ return ret;
+}
+
static inline u_int8_t *msgb_tlv16_put(struct msgb *msg, u_int8_t tag, u_int8_t len, const u_int16_t *val)
{
u_int8_t *buf = msgb_put(msg, TLV16_GROSS_LEN(len));
@@ -62,6 +98,13 @@
return tl16v_put(buf, tag, len, val);
}
+static inline u_int8_t *msgb_tvlv_put(struct msgb *msg, u_int8_t tag, u_int16_t len,
+ const u_int8_t *val)
+{
+ u_int8_t *buf = msgb_put(msg, TVLV_GROSS_LEN(len));
+ return tvlv_put(buf, tag, len, val);
+}
+
static inline u_int8_t *v_put(u_int8_t *buf, u_int8_t val)
{
*buf++ = val;
@@ -146,6 +189,7 @@
TLV_TYPE_TV,
TLV_TYPE_TLV,
TLV_TYPE_TL16V,
+ TLV_TYPE_TvLV,
};
struct tlv_def {
@@ -161,6 +205,8 @@
struct tlv_p_entry lv[0xff];
};
+extern struct tlv_definition tvlv_att_def;
+
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);
diff --git a/openbsc/src/tlv_parser.c b/openbsc/src/tlv_parser.c
index e835f95..8321b88 100644
--- a/openbsc/src/tlv_parser.c
+++ b/openbsc/src/tlv_parser.c
@@ -1,5 +1,8 @@
#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)
{
@@ -87,6 +90,20 @@
return -2;
num_parsed++;
break;
+ case TLV_TYPE_TvLV:
+ if (*(pos+1) & 0x80) {
+ /* like TLV, but without highest bit of len */
+ if (pos + 1 > buf + buf_len)
+ return -1;
+ dec->lv[tag].val = pos+2;
+ dec->lv[tag].len = *(pos+1) & 0x7f;
+ len = dec->lv[tag].len + 2;
+ if (pos + len > buf + buf_len)
+ return -2;
+ num_parsed++;
+ break;
+ }
+ /* like TL16V, fallthrough */
case TLV_TYPE_TL16V:
if (pos + 2 > buf + buf_len)
return -1;
@@ -103,3 +120,9 @@
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;
+}