diff options
Diffstat (limited to 'drivers/net/wireless/rt2x00/rt2x00crypto.c')
| -rw-r--r-- | drivers/net/wireless/rt2x00/rt2x00crypto.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/drivers/net/wireless/rt2x00/rt2x00crypto.c b/drivers/net/wireless/rt2x00/rt2x00crypto.c new file mode 100644 index 0000000..e1448cf --- /dev/null +++ b/drivers/net/wireless/rt2x00/rt2x00crypto.c @@ -0,0 +1,215 @@ +/* + 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; + } +} + +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 += tx_info->control.icv_len; + + if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) + overhead += tx_info->control.iv_len; + + if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) { + if (key->alg == ALG_TKIP) + overhead += 8; + } + + return overhead; +} + +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 */ + if (iv_len >= 4) + memcpy(&skbdesc->iv, skb->data + header_length, 4); + if (iv_len >= 8) + memcpy(&skbdesc->eiv, skb->data + header_length + 4, 4); + + /* 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)) * 4) + ((!!(skbdesc->eiv)) * 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 */ + if (iv_len >= 4) + memcpy(skb->data + header_length, &skbdesc->iv, 4); + if (iv_len >= 8) + memcpy(skb->data + header_length + 4, &skbdesc->eiv, 4); + + /* 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 then the ICV data. + * When alignment requirements is greater then 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 data */ + if (iv_len >= 4) { + memcpy(skb->data + transfer, &rxdesc->iv, 4); + transfer += 4; + } + + /* Copy EIV data */ + if (iv_len >= 8) { + memcpy(skb->data + transfer, &rxdesc->eiv, 4); + transfer += 4; + } + + /* 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 */ + if (icv_len >= 4) { + memcpy(skb->data + transfer, &rxdesc->icv, 4); + /* + * 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. + */ + transfer += icv_len; + } + + /* IV/EIV/ICV has been inserted into frame */ + rxdesc->size = transfer; + rxdesc->flags &= ~RX_FLAG_IV_STRIPPED; +} |
