Commit 6693be71 authored by Harvey Harrison's avatar Harvey Harrison Committed by John W. Linville
Browse files

mac80211: add utility function to get header length 



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

Signed-off-by: default avatarHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent c9c6950c

include/net/mac80211.h

+6 −0
Original line number Diff line number Diff line
@@ -1547,6 +1547,12 @@ unsigned 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

 *

net/mac80211/util.c

+32 −0
Original line number Diff line number Diff line
@@ -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_is_data_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);



unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)

{

	const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data;