[PATCH 3/7] mac80211: add utility function to get header length

Harvey Harrison
2008-06-06T17:59:47Z

Take a __le16 directly rather than a host-endian value.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
include/net/mac80211.h | 6 ++++++
net/mac80211/util.c | 32 ++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 1196de8..53c3b5e 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1548,6 +1548,12 @@ int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb);
int ieee80211_get_hdrlen(u16 fc);

/**
+ * ieee80211_hdrlen - get header length in bytes from frame control
+ * @fc: frame control field in little-endian format
+ */
+unsigned int ieee80211_hdrlen(__le16 fc);
+
+/**
* ieee80211_get_tkip_key - get a TKIP rc4 for skb
*
* This function computes a TKIP rc4 key for an skb. It computes
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 6513bc2..fade001 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -133,6 +133,38 @@ int ieee80211_get_hdrlen(u16 fc)
}
EXPORT_SYMBOL(ieee80211_get_hdrlen);

+unsigned int ieee80211_hdrlen(__le16 fc)
+{
+ unsigned int hdrlen = 24;
+
+ if (ieee80211_is_data(fc)) {
+ if (ieee80211_has_a4(fc))
+ hdrlen = 30;
+ if (ieee80211_data_has_qos(fc))
+ hdrlen += IEEE80211_QOS_CTL_LEN;
+ goto out;
+ }
+
+ if (ieee80211_is_ctl(fc)) {
+ /*
+ * ACK and CTS are 10 bytes, all others 16. To see how
+ * to get this condition consider
+ * subtype mask: 0b0000000011110000 (0x00F0)
+ * ACK subtype: 0b0000000011010000 (0x00D0)
+ * CTS subtype: 0b0000000011000000 (0x00C0)
+ * bits that matter: ^^^ (0x00E0)
+ * value of those: 0b0000000011000000 (0x00C0)
+ */
+ if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
+ hdrlen = 10;
+ else
+ hdrlen = 16;
+ }
+out:
+ return hdrlen;
+}
+EXPORT_SYMBOL(ieee80211_hdrlen);
+
int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
{
const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
--
1.5.6.rc1.257.gba91d