diff options
Diffstat (limited to 'drivers/net/wireless/ralink/rt2x00/rt2x00crypto.c')
| -rw-r--r-- | drivers/net/wireless/ralink/rt2x00/rt2x00crypto.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00crypto.c b/drivers/net/wireless/ralink/rt2x00/rt2x00crypto.c new file mode 100644 index 000000000000..a2fd05ba25ca --- /dev/null +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00crypto.c @@ -0,0 +1,256 @@ +/* + Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com> + <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, see <http://www.gnu.org/licenses/>. + */ + +/* + 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->cipher) { + case WLAN_CIPHER_SUITE_WEP40: + return CIPHER_WEP64; + case WLAN_CIPHER_SUITE_WEP104: + return CIPHER_WEP128; + case WLAN_CIPHER_SUITE_TKIP: + return CIPHER_TKIP; + case WLAN_CIPHER_SUITE_CCMP: + return CIPHER_AES; + default: + return CIPHER_NONE; + } +} + +void rt2x00crypto_create_tx_descriptor(struct rt2x00_dev *rt2x00dev, + struct sk_buff *skb, + struct txentry_desc *txdesc) +{ + struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb); + struct ieee80211_key_conf *hw_key = tx_info->control.hw_key; + + if (!rt2x00_has_cap_hw_crypto(rt2x00dev) || !hw_key) + return; + + __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 = txdesc->header_length; + txdesc->iv_len = hw_key->iv_len; + + 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 rt2x00_dev *rt2x00dev, + struct sk_buff *skb) +{ + struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb); + struct ieee80211_key_conf *key = tx_info->control.hw_key; + unsigned int overhead = 0; + + if (!rt2x00_has_cap_hw_crypto(rt2x00dev) || !key) + return overhead; + + /* + * 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->cipher == WLAN_CIPHER_SUITE_TKIP) + overhead += 8; + } + + return overhead; +} + +void rt2x00crypto_tx_copy_iv(struct sk_buff *skb, struct txentry_desc *txdesc) +{ + struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); + + if (unlikely(!txdesc->iv_len)) + return; + + /* Copy IV/EIV data */ + memcpy(skbdesc->iv, skb->data + txdesc->iv_offset, txdesc->iv_len); +} + +void rt2x00crypto_tx_remove_iv(struct sk_buff *skb, struct txentry_desc *txdesc) +{ + struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); + + if (unlikely(!txdesc->iv_len)) + return; + + /* Copy IV/EIV data */ + memcpy(skbdesc->iv, skb->data + txdesc->iv_offset, txdesc->iv_len); + + /* Move ieee80211 header */ + memmove(skb->data + txdesc->iv_len, skb->data, txdesc->iv_offset); + + /* Pull buffer to correct size */ + skb_pull(skb, txdesc->iv_len); + txdesc->length -= txdesc->iv_len; + + /* IV/EIV data has officially been stripped */ + skbdesc->flags |= SKBDESC_IV_STRIPPED; +} + +void rt2x00crypto_tx_insert_iv(struct sk_buff *skb, unsigned int header_length) +{ + struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); + const unsigned int iv_len = + ((!!(skbdesc->iv[0])) * 4) + ((!!(skbdesc->iv[1])) * 4); + + if (!(skbdesc->flags & SKBDESC_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 &= ~SKBDESC_IV_STRIPPED; +} + +void rt2x00crypto_rx_insert_iv(struct sk_buff *skb, + unsigned int header_length, + struct rxdone_entry_desc *rxdesc) +{ + unsigned int payload_len = rxdesc->size - header_length; + unsigned int align = ALIGN_SIZE(skb, 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. There are 2 possibilities + * either the alignment is already present between + * the 802.11 header and payload. In that case we + * we have to move the header less then the iv_len + * since we can use the already available l2pad bytes + * for the iv data. + * When the alignment must be added manually we must + * move the header more then iv_len since we must + * make room for the payload move as well. + */ + if (rxdesc->dev_flags & RXDONE_L2PAD) { + skb_push(skb, iv_len - align); + skb_put(skb, icv_len); + + /* Move ieee80211 header */ + memmove(skb->data + transfer, + skb->data + transfer + (iv_len - align), + header_length); + transfer += header_length; + } else { + 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 for alignment purposes. Note that + * this is only needed when no l2 padding is present. + */ + if (!(rxdesc->dev_flags & RXDONE_L2PAD)) { + memmove(skb->data + transfer, + skb->data + transfer + align, + payload_len); + } + + /* + * NOTE: Always count the payload as transferred, + * 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; +} |