mwl8k: Add encapsulation of data packet for crypto

Different tail pads will be needed for crypto depending on the crypto
mode. Add support to encapsulate the packets with appropriate pad
value.
Signed-off-by: NNishant Sarmukadam <nishants@marvell.com>
Signed-off-by: NPradeep Nemavat <pnemavat@marvell.com>
Signed-off-by: NThomas Pedersen <thomas@cozybit.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwl8k.c

@@ -232,6 +232,9 @@ struct mwl8k_priv {
 	struct completion firmware_loading_complete;
 };
 
+#define MAX_WEP_KEY_LEN         13
+#define NUM_WEP_KEYS            4
+
 /* Per interface specific private data */
 struct mwl8k_vif {
 	struct list_head list;
@@ -242,6 +245,12 @@ struct mwl8k_vif {
 
 	/* Non AMPDU sequence number assigned by driver.  */
 	u16 seqno;
+
+	/* Saved WEP keys */
+	struct {
+		u8 enabled;
+		u8 key[sizeof(struct ieee80211_key_conf) + MAX_WEP_KEY_LEN];
+	} wep_key_conf[NUM_WEP_KEYS];
 };
 #define MWL8K_VIF(_vif) ((struct mwl8k_vif *)&((_vif)->drv_priv))
 
@@ -754,6 +763,49 @@ mwl8k_add_dma_header(struct sk_buff *skb, int tail_pad)
 	tr->fwlen = cpu_to_le16(skb->len - sizeof(*tr) + tail_pad);
 }
 
+static void mwl8k_encapsulate_tx_frame(struct sk_buff *skb)
+{
+	struct ieee80211_hdr *wh;
+	struct ieee80211_tx_info *tx_info;
+	struct ieee80211_key_conf *key_conf;
+	int data_pad;
+
+	wh = (struct ieee80211_hdr *)skb->data;
+
+	tx_info = IEEE80211_SKB_CB(skb);
+
+	key_conf = NULL;
+	if (ieee80211_is_data(wh->frame_control))
+		key_conf = tx_info->control.hw_key;
+
+	/*
+	 * Make sure the packet header is in the DMA header format (4-address
+	 * without QoS), the necessary crypto padding between the header and the
+	 * payload has already been provided by mac80211, but it doesn't add tail
+	 * padding when HW crypto is enabled.
+	 *
+	 * We have the following trailer padding requirements:
+	 * - WEP: 4 trailer bytes (ICV)
+	 * - TKIP: 12 trailer bytes (8 MIC + 4 ICV)
+	 * - CCMP: 8 trailer bytes (MIC)
+	 */
+	data_pad = 0;
+	if (key_conf != NULL) {
+		switch (key_conf->cipher) {
+		case WLAN_CIPHER_SUITE_WEP40:
+		case WLAN_CIPHER_SUITE_WEP104:
+			data_pad = 4;
+			break;
+		case WLAN_CIPHER_SUITE_TKIP:
+			data_pad = 12;
+			break;
+		case WLAN_CIPHER_SUITE_CCMP:
+			data_pad = 8;
+			break;
+		}
+	}
+	mwl8k_add_dma_header(skb, data_pad);
+}
 
 /*
  * Packet reception for 88w8366 AP firmware.
@@ -1447,7 +1499,7 @@ mwl8k_txq_xmit(struct ieee80211_hw *hw, int index, struct sk_buff *skb)
 	else
 		qos = 0;
 
-	mwl8k_add_dma_header(skb, 0);
+	mwl8k_encapsulate_tx_frame(skb);
 	wh = &((struct mwl8k_dma_data *)skb->data)->wh;
 
 	tx_info = IEEE80211_SKB_CB(skb);