From 458ac1aba44b3287c539431f098ce3de26480274 Mon Sep 17 00:00:00 2001
From: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Date: Tue, 8 Jul 2014 15:03:38 +0300
Subject: [PATCH] ie: Simple informational element parser

The parsing API goes through the byte stream and parses the
TLV (Type, Length and Value) values and avoids data copying.
---
 Makefile.am |  2 +-
 src/ie.c    | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/ie.h    | 14 ++++++++++++
 3 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 src/ie.c

diff --git a/Makefile.am b/Makefile.am
index c23ff105..40938d25 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -40,7 +40,7 @@ src_iwd_SOURCES = src/main.c linux/nl80211.h linux/kdbus.h \
 					src/kdbus.h src/kdbus.c \
 					src/netdev.h src/netdev.c \
 					src/sha1.h src/sha1.c \
-					src/ie.h
+					src/ie.h src/ie.c
 src_iwd_LDADD = ell/libell-internal.la
 
 client_iwctl_SOURCES = client/main.c linux/kdbus.h \
diff --git a/src/ie.c b/src/ie.c
new file mode 100644
index 00000000..35057cf7
--- /dev/null
+++ b/src/ie.c
@@ -0,0 +1,65 @@
+/*
+ *
+ *  Wireless daemon for Linux
+ *
+ *  Copyright (C) 2014  Intel Corporation. All rights reserved.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <errno.h>
+#include <ell/ell.h>
+
+#include "ie.h"
+
+void ie_tlv_iter_init(struct ie_tlv_iter *iter, const unsigned char *tlv,
+			unsigned int len)
+{
+	iter->tlv = tlv;
+	iter->max = len;
+	iter->pos = 0;
+}
+
+unsigned int ie_tlv_iter_get_tag(struct ie_tlv_iter *iter)
+{
+	return iter->tag;
+}
+
+bool ie_tlv_iter_next(struct ie_tlv_iter *iter)
+{
+	const unsigned char *tlv = iter->tlv + iter->pos;
+	const unsigned char *end = iter->tlv + iter->max;
+	unsigned int tag;
+	unsigned int len;
+
+	tag = *tlv++;
+	len = *tlv++;
+
+	if (tlv + len > end)
+		return false;
+
+	iter->tag = tag;
+	iter->len = len;
+	iter->data = tlv;
+
+	iter->pos = tlv + len - iter->tlv;
+
+	return true;
+}
diff --git a/src/ie.h b/src/ie.h
index fb57781a..8b3faa7f 100644
--- a/src/ie.h
+++ b/src/ie.h
@@ -153,3 +153,17 @@ enum ie_type {
 	IE_TYPE_VENDOR_SPECIFIC                      = 221,
 	/* Reserved 222 - 255 */
 };
+
+struct ie_tlv_iter {
+	unsigned int max;
+	unsigned int pos;
+	const unsigned char *tlv;
+	unsigned int tag;
+	unsigned int len;
+	const unsigned char *data;
+};
+
+void ie_tlv_iter_init(struct ie_tlv_iter *iter, const unsigned char *tlv,
+			unsigned int len);
+unsigned int ie_tlv_iter_get_tag(struct ie_tlv_iter *iter);
+bool ie_tlv_iter_next(struct ie_tlv_iter *iter);