drivers/net/wireless/ralink/rt2x00/rt2x00crypto.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3         Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
   4         <http://rt2x00.serialmonkey.com>
   5
   6  */
   7
   8 /*
   9         Module: rt2x00lib
  10         Abstract: rt2x00 crypto specific routines.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15
  16 #include "rt2x00.h"
  17 #include "rt2x00lib.h"
  18
  19 enum cipher rt2x00crypto_key_to_cipher(struct ieee80211_key_conf *key)
  20 {
  21         switch (key->cipher) {
  22         case WLAN_CIPHER_SUITE_WEP40:
  23                 return CIPHER_WEP64;
  24         case WLAN_CIPHER_SUITE_WEP104:
  25                 return CIPHER_WEP128;
  26         case WLAN_CIPHER_SUITE_TKIP:
  27                 return CIPHER_TKIP;
  28         case WLAN_CIPHER_SUITE_CCMP:
  29                 return CIPHER_AES;
  30         default:
  31                 return CIPHER_NONE;
  32         }
  33 }
  34
  35 void rt2x00crypto_create_tx_descriptor(struct rt2x00_dev *rt2x00dev,
  36                                        struct sk_buff *skb,
  37                                        struct txentry_desc *txdesc)
  38 {
  39         struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
  40         struct ieee80211_key_conf *hw_key = tx_info->control.hw_key;
  41
  42         if (!rt2x00_has_cap_hw_crypto(rt2x00dev) || !hw_key)
  43                 return;
  44
  45         __set_bit(ENTRY_TXD_ENCRYPT, &txdesc->flags);
  46
  47         txdesc->cipher = rt2x00crypto_key_to_cipher(hw_key);
  48
  49         if (hw_key->flags & IEEE80211_KEY_FLAG_PAIRWISE)
  50                 __set_bit(ENTRY_TXD_ENCRYPT_PAIRWISE, &txdesc->flags);
  51
  52         txdesc->key_idx = hw_key->hw_key_idx;
  53         txdesc->iv_offset = txdesc->header_length;
  54         txdesc->iv_len = hw_key->iv_len;
  55
  56         if (!(hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
  57                 __set_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc->flags);
  58
  59         if (!(hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC))
  60                 __set_bit(ENTRY_TXD_ENCRYPT_MMIC, &txdesc->flags);
  61 }
  62
  63 unsigned int rt2x00crypto_tx_overhead(struct rt2x00_dev *rt2x00dev,
  64                                       struct sk_buff *skb)
  65 {
  66         struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
  67         struct ieee80211_key_conf *key = tx_info->control.hw_key;
  68         unsigned int overhead = 0;
  69
  70         if (!rt2x00_has_cap_hw_crypto(rt2x00dev) || !key)
  71                 return overhead;
  72
  73         /*
  74          * Extend frame length to include IV/EIV/ICV/MMIC,
  75          * note that these lengths should only be added when
  76          * mac80211 does not generate it.
  77          */
  78         overhead += key->icv_len;
  79
  80         if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
  81                 overhead += key->iv_len;
  82
  83         if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
  84                 if (key->cipher == WLAN_CIPHER_SUITE_TKIP)
  85                         overhead += 8;
  86         }
  87
  88         return overhead;
  89 }
  90
  91 void rt2x00crypto_tx_copy_iv(struct sk_buff *skb, struct txentry_desc *txdesc)
  92 {
  93         struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
  94
  95         if (unlikely(!txdesc->iv_len))
  96                 return;
  97
  98         /* Copy IV/EIV data */
  99         memcpy(skbdesc->iv, skb->data + txdesc->iv_offset, txdesc->iv_len);
 100 }
 101
 102 void rt2x00crypto_tx_remove_iv(struct sk_buff *skb, struct txentry_desc *txdesc)
 103 {
 104         struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
 105
 106         if (unlikely(!txdesc->iv_len))
 107                 return;
 108
 109         /* Copy IV/EIV data */
 110         memcpy(skbdesc->iv, skb->data + txdesc->iv_offset, txdesc->iv_len);
 111
 112         /* Move ieee80211 header */
 113         memmove(skb->data + txdesc->iv_len, skb->data, txdesc->iv_offset);
 114
 115         /* Pull buffer to correct size */
 116         skb_pull(skb, txdesc->iv_len);
 117         txdesc->length -= txdesc->iv_len;
 118
 119         /* IV/EIV data has officially been stripped */
 120         skbdesc->flags |= SKBDESC_IV_STRIPPED;
 121 }
 122
 123 void rt2x00crypto_tx_insert_iv(struct sk_buff *skb, unsigned int header_length)
 124 {
 125         struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
 126         const unsigned int iv_len =
 127             ((!!(skbdesc->iv[0])) * 4) + ((!!(skbdesc->iv[1])) * 4);
 128
 129         if (!(skbdesc->flags & SKBDESC_IV_STRIPPED))
 130                 return;
 131
 132         skb_push(skb, iv_len);
 133
 134         /* Move ieee80211 header */
 135         memmove(skb->data, skb->data + iv_len, header_length);
 136
 137         /* Copy IV/EIV data */
 138         memcpy(skb->data + header_length, skbdesc->iv, iv_len);
 139
 140         /* IV/EIV data has returned into the frame */
 141         skbdesc->flags &= ~SKBDESC_IV_STRIPPED;
 142 }
 143
 144 void rt2x00crypto_rx_insert_iv(struct sk_buff *skb,
 145                                unsigned int header_length,
 146                                struct rxdone_entry_desc *rxdesc)
 147 {
 148         unsigned int payload_len = rxdesc->size - header_length;
 149         unsigned int align = ALIGN_SIZE(skb, header_length);
 150         unsigned int iv_len;
 151         unsigned int icv_len;
 152         unsigned int transfer = 0;
 153
 154         /*
 155          * WEP64/WEP128: Provides IV & ICV
 156          * TKIP: Provides IV/EIV & ICV
 157          * AES: Provies IV/EIV & ICV
 158          */
 159         switch (rxdesc->cipher) {
 160         case CIPHER_WEP64:
 161         case CIPHER_WEP128:
 162                 iv_len = 4;
 163                 icv_len = 4;
 164                 break;
 165         case CIPHER_TKIP:
 166                 iv_len = 8;
 167                 icv_len = 4;
 168                 break;
 169         case CIPHER_AES:
 170                 iv_len = 8;
 171                 icv_len = 8;
 172                 break;
 173         default:
 174                 /* Unsupport type */
 175                 return;
 176         }
 177
 178         /*
 179          * Make room for new data. There are 2 possibilities
 180          * either the alignment is already present between
 181          * the 802.11 header and payload. In that case we
 182          * we have to move the header less then the iv_len
 183          * since we can use the already available l2pad bytes
 184          * for the iv data.
 185          * When the alignment must be added manually we must
 186          * move the header more then iv_len since we must
 187          * make room for the payload move as well.
 188          */
 189         if (rxdesc->dev_flags & RXDONE_L2PAD) {
 190                 skb_push(skb, iv_len - align);
 191                 skb_put(skb, icv_len);
 192
 193                 /* Move ieee80211 header */
 194                 memmove(skb->data + transfer,
 195                         skb->data + transfer + (iv_len - align),
 196                         header_length);
 197                 transfer += header_length;
 198         } else {
 199                 skb_push(skb, iv_len + align);
 200                 if (align < icv_len)
 201                         skb_put(skb, icv_len - align);
 202                 else if (align > icv_len)
 203                         skb_trim(skb, rxdesc->size + iv_len + icv_len);
 204
 205                 /* Move ieee80211 header */
 206                 memmove(skb->data + transfer,
 207                         skb->data + transfer + iv_len + align,
 208                         header_length);
 209                 transfer += header_length;
 210         }
 211
 212         /* Copy IV/EIV data */
 213         memcpy(skb->data + transfer, rxdesc->iv, iv_len);
 214         transfer += iv_len;
 215
 216         /*
 217          * Move payload for alignment purposes. Note that
 218          * this is only needed when no l2 padding is present.
 219          */
 220         if (!(rxdesc->dev_flags & RXDONE_L2PAD)) {
 221                 memmove(skb->data + transfer,
 222                         skb->data + transfer + align,
 223                         payload_len);
 224         }
 225
 226         /*
 227          * NOTE: Always count the payload as transferred,
 228          * even when alignment was set to zero. This is required
 229          * for determining the correct offset for the ICV data.
 230          */
 231         transfer += payload_len;
 232
 233         /*
 234          * Copy ICV data
 235          * AES appends 8 bytes, we can't fill the upper
 236          * 4 bytes, but mac80211 doesn't care about what
 237          * we provide here anyway and strips it immediately.
 238          */
 239         memcpy(skb->data + transfer, &rxdesc->icv, 4);
 240         transfer += icv_len;
 241
 242         /* IV/EIV/ICV has been inserted into frame */
 243         rxdesc->size = transfer;
 244         rxdesc->flags &= ~RX_FLAG_IV_STRIPPED;
 245 }