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mac80211: add utility function to get header length

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

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Harvey Harrison 2008-06-11 14:21:57 -07:00 committed by John W. Linville
parent c9c6950c14
commit 6693be7124
2 changed files with 38 additions and 0 deletions
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6
include/net/mac80211.h
View File

@ -1547,6 +1547,12 @@ unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb);
*/ */
int ieee80211_get_hdrlen(u16 fc); 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 * ieee80211_get_tkip_key - get a TKIP rc4 for skb
* *

32
net/mac80211/util.c
View File

@ -133,6 +133,38 @@ int ieee80211_get_hdrlen(u16 fc)
} }
EXPORT_SYMBOL(ieee80211_get_hdrlen); 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) unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
{ {
const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data; const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data;