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/*
Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
<http://rt2x00.serialmonkey.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the
Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/*
Module: rt2x00lib
Abstract: rt2x00 crypto specific routines.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include "rt2x00.h"
#include "rt2x00lib.h"
enum cipher rt2x00crypto_key_to_cipher(struct ieee80211_key_conf *key)
{
switch (key->alg) {
case ALG_WEP:
if (key->keylen == LEN_WEP40)
return CIPHER_WEP64;
else
return CIPHER_WEP128;
case ALG_TKIP:
return CIPHER_TKIP;
case ALG_CCMP:
return CIPHER_AES;
default:
return CIPHER_NONE;
}
}
void rt2x00crypto_create_tx_descriptor(struct queue_entry *entry,
struct txentry_desc *txdesc)
{
struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(entry->skb);
struct ieee80211_key_conf *hw_key = tx_info->control.hw_key;
__set_bit(ENTRY_TXD_ENCRYPT, &txdesc->flags);
txdesc->cipher = rt2x00crypto_key_to_cipher(hw_key);
if (hw_key->flags & IEEE80211_KEY_FLAG_PAIRWISE)
__set_bit(ENTRY_TXD_ENCRYPT_PAIRWISE, &txdesc->flags);
txdesc->key_idx = hw_key->hw_key_idx;
txdesc->iv_offset = ieee80211_get_hdrlen_from_skb(entry->skb);
if (!(hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
__set_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc->flags);
if (!(hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC))
__set_bit(ENTRY_TXD_ENCRYPT_MMIC, &txdesc->flags);
}
unsigned int rt2x00crypto_tx_overhead(struct ieee80211_tx_info *tx_info)
{
struct ieee80211_key_conf *key = tx_info->control.hw_key;
unsigned int overhead = 0;
/*
* Extend frame length to include IV/EIV/ICV/MMIC,
* note that these lengths should only be added when
* mac80211 does not generate it.
*/
overhead += key->icv_len;
if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
overhead += key->iv_len;
if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
if (key->alg == ALG_TKIP)
overhead += 8;
}
return overhead;
}
void rt2x00crypto_tx_copy_iv(struct sk_buff *skb, unsigned int iv_len)
{
struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
if (unlikely(!iv_len))
return;
/* Copy IV/EIV data */
memcpy(skbdesc->iv, skb->data + header_length, iv_len);
}
void rt2x00crypto_tx_remove_iv(struct sk_buff *skb, unsigned int iv_len)
{
struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
if (unlikely(!iv_len))
return;
/* Copy IV/EIV data */
memcpy(skbdesc->iv, skb->data + header_length, iv_len);
/* Move ieee80211 header */
memmove(skb->data + iv_len, skb->data, header_length);
/* Pull buffer to correct size */
skb_pull(skb, iv_len);
/* IV/EIV data has officially be stripped */
skbdesc->flags |= FRAME_DESC_IV_STRIPPED;
}
void rt2x00crypto_tx_insert_iv(struct sk_buff *skb)
{
struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
const unsigned int iv_len =
((!!(skbdesc->iv[0])) * 4) + ((!!(skbdesc->iv[1])) * 4);
if (!(skbdesc->flags & FRAME_DESC_IV_STRIPPED))
return;
skb_push(skb, iv_len);
/* Move ieee80211 header */
memmove(skb->data, skb->data + iv_len, header_length);
/* Copy IV/EIV data */
memcpy(skb->data + header_length, skbdesc->iv, iv_len);
/* IV/EIV data has returned into the frame */
skbdesc->flags &= ~FRAME_DESC_IV_STRIPPED;
}
void rt2x00crypto_rx_insert_iv(struct sk_buff *skb, unsigned int align,
unsigned int header_length,
struct rxdone_entry_desc *rxdesc)
{
unsigned int payload_len = rxdesc->size - header_length;
unsigned int iv_len;
unsigned int icv_len;
unsigned int transfer = 0;
/*
* WEP64/WEP128: Provides IV & ICV
* TKIP: Provides IV/EIV & ICV
* AES: Provies IV/EIV & ICV
*/
switch (rxdesc->cipher) {
case CIPHER_WEP64:
case CIPHER_WEP128:
iv_len = 4;
icv_len = 4;
break;
case CIPHER_TKIP:
iv_len = 8;
icv_len = 4;
break;
case CIPHER_AES:
iv_len = 8;
icv_len = 8;
break;
default:
/* Unsupport type */
return;
}
/*
* Make room for new data, note that we increase both
* headsize and tailsize when required. The tailsize is
* only needed when ICV data needs to be inserted and
* the padding is smaller than the ICV data.
* When alignment requirements is greater than the
* ICV data we must trim the skb to the correct size
* because we need to remove the extra bytes.
*/
skb_push(skb, iv_len + align);
if (align < icv_len)
skb_put(skb, icv_len - align);
else if (align > icv_len)
skb_trim(skb, rxdesc->size + iv_len + icv_len);
/* Move ieee80211 header */
memmove(skb->data + transfer,
skb->data + transfer + iv_len + align,
header_length);
transfer += header_length;
/* Copy IV/EIV data */
memcpy(skb->data + transfer, rxdesc->iv, iv_len);
transfer += iv_len;
/* Move payload */
if (align) {
memmove(skb->data + transfer,
skb->data + transfer + align,
payload_len);
}
/*
* NOTE: Always count the payload as transfered,
* even when alignment was set to zero. This is required
* for determining the correct offset for the ICV data.
*/
transfer += payload_len;
/*
* Copy ICV data
* AES appends 8 bytes, we can't fill the upper
* 4 bytes, but mac80211 doesn't care about what
* we provide here anyway and strips it immediately.
*/
memcpy(skb->data + transfer, &rxdesc->icv, 4);
transfer += icv_len;
/* IV/EIV/ICV has been inserted into frame */
rxdesc->size = transfer;
rxdesc->flags &= ~RX_FLAG_IV_STRIPPED;
}
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