[PATCH] cfg80211: Radiotap parser

Generic code to walk through the fields in a radiotap header, accounting
for nasties like extended "field present" bitfields and alignment rules

Signed-off-by: Andy Green <andy@warmcat.com>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 88171f8ce58a..7edaef6b29d6 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -11,6 +11,44 @@
  * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
  */
 
+
+/* Radiotap header iteration
+ *   implemented in net/wireless/radiotap.c
+ *   docs in Documentation/networking/radiotap-headers.txt
+ */
+/**
+ * struct ieee80211_radiotap_iterator - tracks walk thru present radiotap args
+ * @rtheader: pointer to the radiotap header we are walking through
+ * @max_length: length of radiotap header in cpu byte ordering
+ * @this_arg_index: IEEE80211_RADIOTAP_... index of current arg
+ * @this_arg: pointer to current radiotap arg
+ * @arg_index: internal next argument index
+ * @arg: internal next argument pointer
+ * @next_bitmap: internal pointer to next present u32
+ * @bitmap_shifter: internal shifter for curr u32 bitmap, b0 set == arg present
+ */
+
+struct ieee80211_radiotap_iterator {
+        struct ieee80211_radiotap_header *rtheader;
+        int max_length;
+        int this_arg_index;
+        u8 *this_arg;
+
+        int arg_index;
+        u8 *arg;
+        __le32 *next_bitmap;
+        u32 bitmap_shifter;
+};
+
+extern int ieee80211_radiotap_iterator_init(
+   struct ieee80211_radiotap_iterator *iterator,
+   struct ieee80211_radiotap_header *radiotap_header,
+   int max_length);
+
+extern int ieee80211_radiotap_iterator_next(
+   struct ieee80211_radiotap_iterator *iterator);
+
+
 /* from net/wireless.h */
 struct wiphy;