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1 | /* | |
2 | Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com> | |
3 | <http://rt2x00.serialmonkey.com> | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 2 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program; if not, write to the | |
17 | Free Software Foundation, Inc., | |
18 | 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
19 | */ | |
20 | ||
21 | /* | |
22 | Module: rt2x00lib | |
23 | Abstract: rt2x00 crypto specific routines. | |
24 | */ | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/module.h> | |
28 | ||
29 | #include "rt2x00.h" | |
30 | #include "rt2x00lib.h" | |
31 | ||
32 | enum cipher rt2x00crypto_key_to_cipher(struct ieee80211_key_conf *key) | |
33 | { | |
34 | switch (key->cipher) { | |
35 | case WLAN_CIPHER_SUITE_WEP40: | |
36 | return CIPHER_WEP64; | |
37 | case WLAN_CIPHER_SUITE_WEP104: | |
38 | return CIPHER_WEP128; | |
39 | case WLAN_CIPHER_SUITE_TKIP: | |
40 | return CIPHER_TKIP; | |
41 | case WLAN_CIPHER_SUITE_CCMP: | |
42 | return CIPHER_AES; | |
43 | default: | |
44 | return CIPHER_NONE; | |
45 | } | |
46 | } | |
47 | ||
48 | void rt2x00crypto_create_tx_descriptor(struct queue_entry *entry, | |
49 | struct txentry_desc *txdesc) | |
50 | { | |
51 | struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev; | |
52 | struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(entry->skb); | |
53 | struct ieee80211_key_conf *hw_key = tx_info->control.hw_key; | |
54 | ||
55 | if (!test_bit(CONFIG_SUPPORT_HW_CRYPTO, &rt2x00dev->flags) || !hw_key) | |
56 | return; | |
57 | ||
58 | __set_bit(ENTRY_TXD_ENCRYPT, &txdesc->flags); | |
59 | ||
60 | txdesc->cipher = rt2x00crypto_key_to_cipher(hw_key); | |
61 | ||
62 | if (hw_key->flags & IEEE80211_KEY_FLAG_PAIRWISE) | |
63 | __set_bit(ENTRY_TXD_ENCRYPT_PAIRWISE, &txdesc->flags); | |
64 | ||
65 | txdesc->key_idx = hw_key->hw_key_idx; | |
66 | txdesc->iv_offset = txdesc->header_length; | |
67 | txdesc->iv_len = hw_key->iv_len; | |
68 | ||
69 | if (!(hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) | |
70 | __set_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc->flags); | |
71 | ||
72 | if (!(hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) | |
73 | __set_bit(ENTRY_TXD_ENCRYPT_MMIC, &txdesc->flags); | |
74 | } | |
75 | ||
76 | unsigned int rt2x00crypto_tx_overhead(struct rt2x00_dev *rt2x00dev, | |
77 | struct sk_buff *skb) | |
78 | { | |
79 | struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb); | |
80 | struct ieee80211_key_conf *key = tx_info->control.hw_key; | |
81 | unsigned int overhead = 0; | |
82 | ||
83 | if (!test_bit(CONFIG_SUPPORT_HW_CRYPTO, &rt2x00dev->flags) || !key) | |
84 | return overhead; | |
85 | ||
86 | /* | |
87 | * Extend frame length to include IV/EIV/ICV/MMIC, | |
88 | * note that these lengths should only be added when | |
89 | * mac80211 does not generate it. | |
90 | */ | |
91 | overhead += key->icv_len; | |
92 | ||
93 | if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) | |
94 | overhead += key->iv_len; | |
95 | ||
96 | if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) { | |
97 | if (key->cipher == WLAN_CIPHER_SUITE_TKIP) | |
98 | overhead += 8; | |
99 | } | |
100 | ||
101 | return overhead; | |
102 | } | |
103 | ||
104 | void rt2x00crypto_tx_copy_iv(struct sk_buff *skb, struct txentry_desc *txdesc) | |
105 | { | |
106 | struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); | |
107 | ||
108 | if (unlikely(!txdesc->iv_len)) | |
109 | return; | |
110 | ||
111 | /* Copy IV/EIV data */ | |
112 | memcpy(skbdesc->iv, skb->data + txdesc->iv_offset, txdesc->iv_len); | |
113 | } | |
114 | ||
115 | void rt2x00crypto_tx_remove_iv(struct sk_buff *skb, struct txentry_desc *txdesc) | |
116 | { | |
117 | struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); | |
118 | ||
119 | if (unlikely(!txdesc->iv_len)) | |
120 | return; | |
121 | ||
122 | /* Copy IV/EIV data */ | |
123 | memcpy(skbdesc->iv, skb->data + txdesc->iv_offset, txdesc->iv_len); | |
124 | ||
125 | /* Move ieee80211 header */ | |
126 | memmove(skb->data + txdesc->iv_len, skb->data, txdesc->iv_offset); | |
127 | ||
128 | /* Pull buffer to correct size */ | |
129 | skb_pull(skb, txdesc->iv_len); | |
130 | txdesc->length -= txdesc->iv_len; | |
131 | ||
132 | /* IV/EIV data has officially been stripped */ | |
133 | skbdesc->flags |= SKBDESC_IV_STRIPPED; | |
134 | } | |
135 | ||
136 | void rt2x00crypto_tx_insert_iv(struct sk_buff *skb, unsigned int header_length) | |
137 | { | |
138 | struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); | |
139 | const unsigned int iv_len = | |
140 | ((!!(skbdesc->iv[0])) * 4) + ((!!(skbdesc->iv[1])) * 4); | |
141 | ||
142 | if (!(skbdesc->flags & SKBDESC_IV_STRIPPED)) | |
143 | return; | |
144 | ||
145 | skb_push(skb, iv_len); | |
146 | ||
147 | /* Move ieee80211 header */ | |
148 | memmove(skb->data, skb->data + iv_len, header_length); | |
149 | ||
150 | /* Copy IV/EIV data */ | |
151 | memcpy(skb->data + header_length, skbdesc->iv, iv_len); | |
152 | ||
153 | /* IV/EIV data has returned into the frame */ | |
154 | skbdesc->flags &= ~SKBDESC_IV_STRIPPED; | |
155 | } | |
156 | ||
157 | void rt2x00crypto_rx_insert_iv(struct sk_buff *skb, | |
158 | unsigned int header_length, | |
159 | struct rxdone_entry_desc *rxdesc) | |
160 | { | |
161 | unsigned int payload_len = rxdesc->size - header_length; | |
162 | unsigned int align = ALIGN_SIZE(skb, header_length); | |
163 | unsigned int iv_len; | |
164 | unsigned int icv_len; | |
165 | unsigned int transfer = 0; | |
166 | ||
167 | /* | |
168 | * WEP64/WEP128: Provides IV & ICV | |
169 | * TKIP: Provides IV/EIV & ICV | |
170 | * AES: Provies IV/EIV & ICV | |
171 | */ | |
172 | switch (rxdesc->cipher) { | |
173 | case CIPHER_WEP64: | |
174 | case CIPHER_WEP128: | |
175 | iv_len = 4; | |
176 | icv_len = 4; | |
177 | break; | |
178 | case CIPHER_TKIP: | |
179 | iv_len = 8; | |
180 | icv_len = 4; | |
181 | break; | |
182 | case CIPHER_AES: | |
183 | iv_len = 8; | |
184 | icv_len = 8; | |
185 | break; | |
186 | default: | |
187 | /* Unsupport type */ | |
188 | return; | |
189 | } | |
190 | ||
191 | /* | |
192 | * Make room for new data. There are 2 possibilities | |
193 | * either the alignment is already present between | |
194 | * the 802.11 header and payload. In that case we | |
195 | * we have to move the header less then the iv_len | |
196 | * since we can use the already available l2pad bytes | |
197 | * for the iv data. | |
198 | * When the alignment must be added manually we must | |
199 | * move the header more then iv_len since we must | |
200 | * make room for the payload move as well. | |
201 | */ | |
202 | if (rxdesc->dev_flags & RXDONE_L2PAD) { | |
203 | skb_push(skb, iv_len - align); | |
204 | skb_put(skb, icv_len); | |
205 | ||
206 | /* Move ieee80211 header */ | |
207 | memmove(skb->data + transfer, | |
208 | skb->data + transfer + (iv_len - align), | |
209 | header_length); | |
210 | transfer += header_length; | |
211 | } else { | |
212 | skb_push(skb, iv_len + align); | |
213 | if (align < icv_len) | |
214 | skb_put(skb, icv_len - align); | |
215 | else if (align > icv_len) | |
216 | skb_trim(skb, rxdesc->size + iv_len + icv_len); | |
217 | ||
218 | /* Move ieee80211 header */ | |
219 | memmove(skb->data + transfer, | |
220 | skb->data + transfer + iv_len + align, | |
221 | header_length); | |
222 | transfer += header_length; | |
223 | } | |
224 | ||
225 | /* Copy IV/EIV data */ | |
226 | memcpy(skb->data + transfer, rxdesc->iv, iv_len); | |
227 | transfer += iv_len; | |
228 | ||
229 | /* | |
230 | * Move payload for alignment purposes. Note that | |
231 | * this is only needed when no l2 padding is present. | |
232 | */ | |
233 | if (!(rxdesc->dev_flags & RXDONE_L2PAD)) { | |
234 | memmove(skb->data + transfer, | |
235 | skb->data + transfer + align, | |
236 | payload_len); | |
237 | } | |
238 | ||
239 | /* | |
240 | * NOTE: Always count the payload as transfered, | |
241 | * even when alignment was set to zero. This is required | |
242 | * for determining the correct offset for the ICV data. | |
243 | */ | |
244 | transfer += payload_len; | |
245 | ||
246 | /* | |
247 | * Copy ICV data | |
248 | * AES appends 8 bytes, we can't fill the upper | |
249 | * 4 bytes, but mac80211 doesn't care about what | |
250 | * we provide here anyway and strips it immediately. | |
251 | */ | |
252 | memcpy(skb->data + transfer, &rxdesc->icv, 4); | |
253 | transfer += icv_len; | |
254 | ||
255 | /* IV/EIV/ICV has been inserted into frame */ | |
256 | rxdesc->size = transfer; | |
257 | rxdesc->flags &= ~RX_FLAG_IV_STRIPPED; | |
258 | } |