mac80211: support adding IV-room in the skb for CCMP keys

Some cards can generate CCMP IVs in HW, but require the space for the IV
to be pre-allocated in the frame at the correct offset. Add a key flag
that allows us to achieve this.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index f614ce7bb6e3..13efab5bf12a 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -390,7 +390,8 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
         u8 scratch[6 * AES_BLOCK_SIZE];
 
         if (info->control.hw_key &&
-            !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
+            !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
+            !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
                 /*
                  * hwaccel has no need for preallocated room for CCMP
                  * header or MIC fields
@@ -412,6 +413,11 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
 
         pos = skb_push(skb, CCMP_HDR_LEN);
         memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
+
+        /* the HW only needs room for the IV, but not the actual IV */
+        if (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)
+                return 0;
+
         hdr = (struct ieee80211_hdr *) pos;
         pos += hdrlen;