Commit 81100eb8 authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
Browse files

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
......@@ -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++;
......
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