TLV: add new "vTvLV" type for GAN
This new TLV type is specific to TS 44.318. Contrary to the TvLV type
of TS 08.16/08.18, it has an inverted meaning of the extension (0x80)
bit:
* if the extension bit is not set, 1-byte length
* if the extension bit is set, 2-byte length
Futhermore, it has support for variable-length tags, where the tag part
can be optionally two bytes in length. As this esoteric option hasn't
been seen in the wild yet, we only add encoding support but skip
decoding for now.
diff --git a/include/osmocom/gsm/tlv.h b/include/osmocom/gsm/tlv.h
index d1efc55..9c0319d 100644
--- a/include/osmocom/gsm/tlv.h
+++ b/include/osmocom/gsm/tlv.h
@@ -20,6 +20,7 @@
TL16V 8 16 N * 8
TLV16 8 8 N * 16
TvLV 8 8/16 N * 8
+ vTvLV 8/16 8/16 N * 8
*/
@@ -46,6 +47,36 @@
return TL16V_GROSS_LEN(len);
}
+/*! \brief gross length of vTvL header (tag+len) */
+static inline uint16_t VTVL_GAN_GROSS_LEN(uint16_t tag, uint16_t len)
+{
+ uint16_t ret = 2;
+
+ if (tag > TVLV_MAX_ONEBYTE)
+ ret++;
+
+ if (len > TVLV_MAX_ONEBYTE)
+ ret++;
+
+ return ret;
+}
+
+/*! \brief gross length of vTvLV (tag+len+val) */
+static inline uint16_t VTVLV_GAN_GROSS_LEN(uint16_t tag, uint16_t len)
+{
+ uint16_t ret;
+
+ if (len <= TVLV_MAX_ONEBYTE)
+ return TLV_GROSS_LEN(len);
+ else
+ return TL16V_GROSS_LEN(len);
+
+ if (tag > TVLV_MAX_ONEBYTE)
+ ret += 1;
+
+ return ret;
+}
+
/* TLV generation */
/*! \brief put (append) a LV field */
@@ -103,6 +134,42 @@
return ret;
}
+/*! \brief put (append) a variable-length tag or variable-length length * */
+static inline uint8_t *vt_gan_put(uint8_t *buf, uint16_t tag)
+{
+ if (tag > TVLV_MAX_ONEBYTE) {
+ /* two-byte TAG */
+ *buf++ = 0x80 | (tag >> 8);
+ *buf++ = (tag & 0xff);
+ } else
+ *buf++ = tag;
+
+ return buf;
+}
+
+/* \brief put (append) vTvL (GAN) field (tag + length)*/
+static inline uint8_t *vtvl_gan_put(uint8_t *buf, uint16_t tag, uint16_t len)
+{
+ uint8_t *ret;
+
+ ret = vt_gan_put(buf, tag);
+ return vt_gan_put(ret, len);
+}
+
+/* \brief put (append) vTvLV (GAN) field (tag + length + val) */
+static inline uint8_t *vtvlv_gan_put(uint8_t *buf, uint16_t tag, uint16_t len,
+ const uint8_t *val)
+{
+ uint8_t *ret;
+
+ ret = vtvl_gan_put(buf, tag, len );
+
+ memcpy(ret, val, len);
+ ret = buf + len;
+
+ return ret;
+}
+
/*! \brief put (append) a TLV16 field to \ref msgb */
static inline uint8_t *msgb_tlv16_put(struct msgb *msg, uint8_t tag, uint8_t len, const uint16_t *val)
{
@@ -126,6 +193,14 @@
return tvlv_put(buf, tag, len, val);
}
+/*! \brief put (append) a vTvLV field to \ref msgb */
+static inline uint8_t *msgb_vtvlv_gan_put(struct msgb *msg, uint16_t tag,
+ uint16_t len, const uint8_t *val)
+{
+ uint8_t *buf = msgb_put(msg, VTVLV_GAN_GROSS_LEN(tag, len));
+ return vtvlv_gan_put(buf, tag, len, val);
+}
+
/*! \brief put (append) a L16TV field to \ref msgb */
static inline uint8_t *msgb_l16tv_put(struct msgb *msg, uint16_t len, uint8_t tag,
const uint8_t *val)
@@ -264,6 +339,25 @@
return buf;
}
+/* \brief push (prepend) a vTvL header to a \ref msgb
+ */
+static inline uint8_t *msgb_vtvl_gan_push(struct msgb *msg, uint16_t tag,
+ uint16_t len)
+{
+ uint8_t *buf = msgb_push(msg, VTVL_GAN_GROSS_LEN(tag, len));
+ vtvl_gan_put(buf, tag, len);
+ return buf;
+}
+
+
+static inline uint8_t *msgb_vtvlv_gan_push(struct msgb *msg, uint16_t tag,
+ uint16_t len, const uint8_t *val)
+{
+ uint8_t *buf = msgb_push(msg, VTVLV_GAN_GROSS_LEN(tag, len));
+ vtvlv_gan_put(buf, tag, len, val);
+ return buf;
+}
+
/* TLV parsing */
/*! \brief Entry in a TLV parser array */
@@ -281,7 +375,8 @@
TLV_TYPE_TLV, /*!< \brief tag-length-value */
TLV_TYPE_TL16V, /*!< \brief tag, 16 bit length, value */
TLV_TYPE_TvLV, /*!< \brief tag, variable length, value */
- TLV_TYPE_SINGLE_TV /*!< \brief tag and value (both 4 bit) in 1 byte */
+ TLV_TYPE_SINGLE_TV, /*!< \brief tag and value (both 4 bit) in 1 byte */
+ TLV_TYPE_vTvLV_GAN, /*!< \brief variable-length tag, variable-length length */
};
/*! \brief Definition of a single IE (Information Element) */
@@ -301,6 +396,7 @@
};
extern struct tlv_definition tvlv_att_def;
+extern struct tlv_definition vtvlv_gan_att_def;
int tlv_parse_one(uint8_t *o_tag, uint16_t *o_len, const uint8_t **o_val,
const struct tlv_definition *def,