/* 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, 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 == WLAN_KEY_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 rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev; struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(entry->skb); struct ieee80211_key_conf *hw_key = tx_info->control.hw_key; if (!test_bit(CONFIG_SUPPORT_HW_CRYPTO, &rt2x00dev->flags) || !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 (!test_bit(CONFIG_SUPPORT_HW_CRYPTO, &rt2x00dev->flags) || !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->alg == ALG_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); /* 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 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; }