mac80211: move TKIP TX IVs to public part of key struct

Some drivers/devices might want to set the IVs by
themselves (and still let mac80211 generate MMIC).

Specifically, this is needed when the device does
offloading at certain times, and the driver has
to make sure that the IVs of new tx frames (from
the host) are synchronized with IVs that were
potentially used during the offloading.

Similarly to CCMP, move the TX IVs of TKIP keys to the
public part of the key struct, and export a function
to add the IV right into the crypto header.

The public tx_pn field is defined as atomic64, so define
TKIP_PN_TO_IV16/32 helper macros to convert it to iv16/32
when needed.

Since the iv32 used for the p1k cache is taken
directly from the frame, we can safely remove
iv16/32 from being protected by tkip.txlock.

Signed-off-by: Eliad Peller <eliadx.peller@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 4 insertions, 7 deletions

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index d824c38971ed..18848258adde 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -1,6 +1,7 @@
 /*
  * Copyright 2002-2004, Instant802 Networks, Inc.
  * Copyright 2008, Jouni Malinen <j@w1.fi>
+ * Copyright (C) 2016 Intel Deutschland GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -183,7 +184,6 @@ mic_fail_no_key:
         return RX_DROP_UNUSABLE;
 }
 
-
 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 {
         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
@@ -191,6 +191,7 @@ static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
         unsigned int hdrlen;
         int len, tail;
+        u64 pn;
         u8 *pos;
 
         if (info->control.hw_key &&
@@ -222,12 +223,8 @@ static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
                 return 0;
 
         /* Increase IV for the frame */
-        spin_lock(&key->u.tkip.txlock);
-        key->u.tkip.tx.iv16++;
-        if (key->u.tkip.tx.iv16 == 0)
-                key->u.tkip.tx.iv32++;
-        pos = ieee80211_tkip_add_iv(pos, key);
-        spin_unlock(&key->u.tkip.txlock);
+        pn = atomic64_inc_return(&key->conf.tx_pn);
+        pos = ieee80211_tkip_add_iv(pos, &key->conf, pn);
 
         /* hwaccel - with software IV */
         if (info->control.hw_key)