From 73310c3c835886525b7c6eca73c79bd70d2dd21b Mon Sep 17 00:00:00 2001
From: Harald Welte <laforge@netfilter.org>
Date: Sat, 24 Oct 2009 10:04:02 +0200
Subject: [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.
---
 openbsc/include/openbsc/tlv.h | 46 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

(limited to 'openbsc/include/openbsc/tlv.h')

diff --git a/openbsc/include/openbsc/tlv.h b/openbsc/include/openbsc/tlv.h
index ae88e6ed3..6da4fb16a 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 @@ static inline u_int8_t *tl16v_put(u_int8_t *buf, u_int8_t tag, u_int16_t len,
 	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 @@ static inline u_int8_t *msgb_tl16v_put(struct msgb *msg, u_int8_t tag, u_int16_t
 	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 @@ enum tlv_type {
 	TLV_TYPE_TV,
 	TLV_TYPE_TLV,
 	TLV_TYPE_TL16V,
+	TLV_TYPE_TvLV,
 };
 
 struct tlv_def {
@@ -161,6 +205,8 @@ struct tlv_parsed {
 	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);
 
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