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Commit 81100eb8 authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
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mac80211: warn when receiving frames with unaligned data 



This patch makes mac80211 warn (once) when the driver passes up a
frame in which the payload data is not aligned on a four-byte
boundary, with a long comment for people who run into the condition
and need to know what to do.

Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 0d174406

net/mac80211/rx.c

+13 −0
Original line number Diff line number Diff line
@@ -1443,6 +1443,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb, 
	struct ieee80211_sub_if_data *prev = NULL;

	struct sk_buff *skb_new;

	u8 *bssid;

	int hdrlen;



	/*

	 * key references and virtual interfaces are protected using RCU
@@ -1472,6 +1473,18 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb, 
	rx.fc = le16_to_cpu(hdr->frame_control);

	type = rx.fc & IEEE80211_FCTL_FTYPE;



	/*

	 * Drivers are required to align the payload data to a four-byte

	 * boundary, so the last two bits of the address where it starts

	 * may not be set. The header is required to be directly before

	 * the payload data, padding like atheros hardware adds which is

	 * inbetween the 802.11 header and the payload is not supported,

	 * the driver is required to move the 802.11 header further back

	 * in that case.

	 */

	hdrlen = ieee80211_get_hdrlen(rx.fc);

	WARN_ON_ONCE(((unsigned long)(skb->data + hdrlen)) & 3);



	if (type == IEEE80211_FTYPE_DATA || type == IEEE80211_FTYPE_MGMT)

		local->dot11ReceivedFragmentCount++;