216 lines
5.4 KiB
C
216 lines
5.4 KiB
C
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/*
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Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
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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, write to the
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Free Software Foundation, Inc.,
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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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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->alg) {
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case ALG_WEP:
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if (key->keylen == LEN_WEP40)
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return CIPHER_WEP64;
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else
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return CIPHER_WEP128;
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case ALG_TKIP:
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return CIPHER_TKIP;
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case ALG_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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unsigned int rt2x00crypto_tx_overhead(struct ieee80211_tx_info *tx_info)
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{
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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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/*
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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 += tx_info->control.icv_len;
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if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
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overhead += tx_info->control.iv_len;
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if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
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if (key->alg == ALG_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_remove_iv(struct sk_buff *skb, unsigned int iv_len)
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{
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struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
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unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
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if (unlikely(!iv_len))
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return;
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/* Copy IV/EIV data */
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if (iv_len >= 4)
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memcpy(&skbdesc->iv, skb->data + header_length, 4);
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if (iv_len >= 8)
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memcpy(&skbdesc->eiv, skb->data + header_length + 4, 4);
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/* Move ieee80211 header */
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memmove(skb->data + iv_len, skb->data, header_length);
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/* Pull buffer to correct size */
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skb_pull(skb, iv_len);
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/* IV/EIV data has officially be stripped */
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skbdesc->flags |= FRAME_DESC_IV_STRIPPED;
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}
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void rt2x00crypto_tx_insert_iv(struct sk_buff *skb)
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{
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struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
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unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb);
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const unsigned int iv_len =
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((!!(skbdesc->iv)) * 4) + ((!!(skbdesc->eiv)) * 4);
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if (!(skbdesc->flags & FRAME_DESC_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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if (iv_len >= 4)
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memcpy(skb->data + header_length, &skbdesc->iv, 4);
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if (iv_len >= 8)
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memcpy(skb->data + header_length + 4, &skbdesc->eiv, 4);
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/* IV/EIV data has returned into the frame */
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skbdesc->flags &= ~FRAME_DESC_IV_STRIPPED;
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}
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void rt2x00crypto_rx_insert_iv(struct sk_buff *skb, unsigned int align,
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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 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, note that we increase both
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* headsize and tailsize when required. The tailsize is
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* only needed when ICV data needs to be inserted and
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* the padding is smaller then the ICV data.
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* When alignment requirements is greater then the
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* ICV data we must trim the skb to the correct size
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* because we need to remove the extra bytes.
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*/
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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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/* Copy IV data */
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if (iv_len >= 4) {
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memcpy(skb->data + transfer, &rxdesc->iv, 4);
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transfer += 4;
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}
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/* Copy EIV data */
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if (iv_len >= 8) {
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memcpy(skb->data + transfer, &rxdesc->eiv, 4);
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transfer += 4;
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}
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/* Move payload */
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if (align) {
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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 transfered,
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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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/* Copy ICV data */
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if (icv_len >= 4) {
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memcpy(skb->data + transfer, &rxdesc->icv, 4);
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/*
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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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transfer += icv_len;
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}
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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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