257 lines
6.7 KiB
C
257 lines
6.7 KiB
C
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/*
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Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
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<http://rt2x00.serialmonkey.com>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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Module: rt2x00lib
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Abstract: rt2x00 crypto specific routines.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include "rt2x00.h"
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#include "rt2x00lib.h"
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enum cipher rt2x00crypto_key_to_cipher(struct ieee80211_key_conf *key)
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{
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switch (key->cipher) {
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case WLAN_CIPHER_SUITE_WEP40:
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return CIPHER_WEP64;
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case WLAN_CIPHER_SUITE_WEP104:
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return CIPHER_WEP128;
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case WLAN_CIPHER_SUITE_TKIP:
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return CIPHER_TKIP;
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case WLAN_CIPHER_SUITE_CCMP:
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return CIPHER_AES;
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default:
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return CIPHER_NONE;
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}
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}
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void rt2x00crypto_create_tx_descriptor(struct rt2x00_dev *rt2x00dev,
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struct sk_buff *skb,
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struct txentry_desc *txdesc)
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{
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struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
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struct ieee80211_key_conf *hw_key = tx_info->control.hw_key;
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if (!rt2x00_has_cap_hw_crypto(rt2x00dev) || !hw_key)
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return;
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__set_bit(ENTRY_TXD_ENCRYPT, &txdesc->flags);
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txdesc->cipher = rt2x00crypto_key_to_cipher(hw_key);
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if (hw_key->flags & IEEE80211_KEY_FLAG_PAIRWISE)
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__set_bit(ENTRY_TXD_ENCRYPT_PAIRWISE, &txdesc->flags);
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txdesc->key_idx = hw_key->hw_key_idx;
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txdesc->iv_offset = txdesc->header_length;
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txdesc->iv_len = hw_key->iv_len;
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if (!(hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
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__set_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc->flags);
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if (!(hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC))
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__set_bit(ENTRY_TXD_ENCRYPT_MMIC, &txdesc->flags);
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}
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unsigned int rt2x00crypto_tx_overhead(struct rt2x00_dev *rt2x00dev,
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struct sk_buff *skb)
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{
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struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
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struct ieee80211_key_conf *key = tx_info->control.hw_key;
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unsigned int overhead = 0;
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if (!rt2x00_has_cap_hw_crypto(rt2x00dev) || !key)
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return overhead;
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/*
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* Extend frame length to include IV/EIV/ICV/MMIC,
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* note that these lengths should only be added when
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* mac80211 does not generate it.
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*/
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overhead += key->icv_len;
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if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
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overhead += key->iv_len;
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if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
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if (key->cipher == WLAN_CIPHER_SUITE_TKIP)
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overhead += 8;
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}
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return overhead;
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}
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void rt2x00crypto_tx_copy_iv(struct sk_buff *skb, struct txentry_desc *txdesc)
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{
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struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
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if (unlikely(!txdesc->iv_len))
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return;
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/* Copy IV/EIV data */
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memcpy(skbdesc->iv, skb->data + txdesc->iv_offset, txdesc->iv_len);
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}
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void rt2x00crypto_tx_remove_iv(struct sk_buff *skb, struct txentry_desc *txdesc)
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{
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struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
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if (unlikely(!txdesc->iv_len))
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return;
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/* Copy IV/EIV data */
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memcpy(skbdesc->iv, skb->data + txdesc->iv_offset, txdesc->iv_len);
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/* Move ieee80211 header */
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memmove(skb->data + txdesc->iv_len, skb->data, txdesc->iv_offset);
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/* Pull buffer to correct size */
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skb_pull(skb, txdesc->iv_len);
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txdesc->length -= txdesc->iv_len;
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/* IV/EIV data has officially been stripped */
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skbdesc->flags |= SKBDESC_IV_STRIPPED;
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}
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void rt2x00crypto_tx_insert_iv(struct sk_buff *skb, unsigned int header_length)
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{
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struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
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const unsigned int iv_len =
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((!!(skbdesc->iv[0])) * 4) + ((!!(skbdesc->iv[1])) * 4);
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if (!(skbdesc->flags & SKBDESC_IV_STRIPPED))
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return;
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skb_push(skb, iv_len);
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/* Move ieee80211 header */
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memmove(skb->data, skb->data + iv_len, header_length);
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/* Copy IV/EIV data */
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memcpy(skb->data + header_length, skbdesc->iv, iv_len);
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/* IV/EIV data has returned into the frame */
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skbdesc->flags &= ~SKBDESC_IV_STRIPPED;
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}
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void rt2x00crypto_rx_insert_iv(struct sk_buff *skb,
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unsigned int header_length,
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struct rxdone_entry_desc *rxdesc)
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{
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unsigned int payload_len = rxdesc->size - header_length;
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unsigned int align = ALIGN_SIZE(skb, header_length);
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unsigned int iv_len;
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unsigned int icv_len;
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unsigned int transfer = 0;
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/*
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* WEP64/WEP128: Provides IV & ICV
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* TKIP: Provides IV/EIV & ICV
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* AES: Provies IV/EIV & ICV
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*/
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switch (rxdesc->cipher) {
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case CIPHER_WEP64:
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case CIPHER_WEP128:
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iv_len = 4;
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icv_len = 4;
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break;
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case CIPHER_TKIP:
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iv_len = 8;
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icv_len = 4;
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break;
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case CIPHER_AES:
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iv_len = 8;
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icv_len = 8;
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break;
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default:
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/* Unsupport type */
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return;
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}
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/*
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* Make room for new data. There are 2 possibilities
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* either the alignment is already present between
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* the 802.11 header and payload. In that case we
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* we have to move the header less then the iv_len
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* since we can use the already available l2pad bytes
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* for the iv data.
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* When the alignment must be added manually we must
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* move the header more then iv_len since we must
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* make room for the payload move as well.
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*/
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if (rxdesc->dev_flags & RXDONE_L2PAD) {
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skb_push(skb, iv_len - align);
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skb_put(skb, icv_len);
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/* Move ieee80211 header */
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memmove(skb->data + transfer,
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skb->data + transfer + (iv_len - align),
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header_length);
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transfer += header_length;
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} else {
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skb_push(skb, iv_len + align);
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if (align < icv_len)
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skb_put(skb, icv_len - align);
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else if (align > icv_len)
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skb_trim(skb, rxdesc->size + iv_len + icv_len);
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/* Move ieee80211 header */
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memmove(skb->data + transfer,
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skb->data + transfer + iv_len + align,
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header_length);
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transfer += header_length;
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}
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/* Copy IV/EIV data */
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memcpy(skb->data + transfer, rxdesc->iv, iv_len);
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transfer += iv_len;
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/*
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* Move payload for alignment purposes. Note that
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* this is only needed when no l2 padding is present.
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*/
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if (!(rxdesc->dev_flags & RXDONE_L2PAD)) {
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memmove(skb->data + transfer,
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skb->data + transfer + align,
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payload_len);
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}
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/*
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* NOTE: Always count the payload as transferred,
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* even when alignment was set to zero. This is required
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* for determining the correct offset for the ICV data.
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*/
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transfer += payload_len;
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/*
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* Copy ICV data
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* AES appends 8 bytes, we can't fill the upper
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* 4 bytes, but mac80211 doesn't care about what
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* we provide here anyway and strips it immediately.
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*/
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memcpy(skb->data + transfer, &rxdesc->icv, 4);
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transfer += icv_len;
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/* IV/EIV/ICV has been inserted into frame */
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rxdesc->size = transfer;
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rxdesc->flags &= ~RX_FLAG_IV_STRIPPED;
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}
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