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mac80211: fix alignment warning

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When I introduced the alignment warning I forgot the A-MSDU case which
has a different requirement because each frame contains 14-byte 802.3
headers in front of the IP payload. This patch moves the alignment
warning to a place where we know whether we're dealing with an A-MSDU
frame and adjusts it accordingly.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Johannes Berg 2008-01-11 02:02:51 +01:00 committed by David S. Miller
parent 4bdb0fba9e
commit 691ba2346d
1 changed files with 33 additions and 13 deletions
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46
net/mac80211/rx.c
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@ -340,9 +340,42 @@ static u32 ieee80211_rx_load_stats(struct ieee80211_local *local,
return load;
}
static ieee80211_txrx_result
ieee80211_rx_h_verify_ip_alignment(struct ieee80211_txrx_data *rx)
{
int hdrlen;
/*
* Drivers are required to align the payload data in a way that
* guarantees that the contained IP header is aligned to a four-
* byte boundary. In the case of regular frames, this simply means
* aligning the payload to a four-byte boundary (because either
* the IP header is directly contained, or IV/RFC1042 headers that
* have a length divisible by four are in front of it.
*
* With A-MSDU frames, however, the payload data address must
* yield two modulo four because there are 14-byte 802.3 headers
* within the A-MSDU frames that push the IP header further back
* to a multiple of four again. Thankfully, the specs were sane
* enough this time around to require padding each A-MSDU subframe
* to a length that is a multiple of four.
*
* 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);
if (rx->flags & IEEE80211_TXRXD_RX_AMSDU)
hdrlen += ETH_HLEN;
WARN_ON_ONCE(((unsigned long)(rx->skb->data + hdrlen)) & 3);
return TXRX_CONTINUE;
}
ieee80211_rx_handler ieee80211_rx_pre_handlers[] =
{
ieee80211_rx_h_parse_qos,
ieee80211_rx_h_verify_ip_alignment,
NULL
};
@ -1679,7 +1712,6 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
struct ieee80211_sub_if_data *prev = NULL;
struct sk_buff *skb_new;
u8 *bssid;
int hdrlen;
hdr = (struct ieee80211_hdr *) skb->data;
memset(&rx, 0, sizeof(rx));
@ -1691,18 +1723,6 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
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++;