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2bb057d0 ID |
1 | /* |
2 | Copyright (C) 2004 - 2008 rt2x00 SourceForge Project | |
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->alg) { | |
35 | case ALG_WEP: | |
36 | if (key->keylen == LEN_WEP40) | |
37 | return CIPHER_WEP64; | |
38 | else | |
39 | return CIPHER_WEP128; | |
40 | case ALG_TKIP: | |
41 | return CIPHER_TKIP; | |
42 | case ALG_CCMP: | |
43 | return CIPHER_AES; | |
44 | default: | |
45 | return CIPHER_NONE; | |
46 | } | |
47 | } | |
48 | ||
49 | unsigned int rt2x00crypto_tx_overhead(struct ieee80211_tx_info *tx_info) | |
50 | { | |
51 | struct ieee80211_key_conf *key = tx_info->control.hw_key; | |
52 | unsigned int overhead = 0; | |
53 | ||
54 | /* | |
55 | * Extend frame length to include IV/EIV/ICV/MMIC, | |
56 | * note that these lengths should only be added when | |
57 | * mac80211 does not generate it. | |
58 | */ | |
76708dee | 59 | overhead += key->icv_len; |
2bb057d0 ID |
60 | |
61 | if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) | |
76708dee | 62 | overhead += key->iv_len; |
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63 | |
64 | if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) { | |
65 | if (key->alg == ALG_TKIP) | |
66 | overhead += 8; | |
67 | } | |
68 | ||
69 | return overhead; | |
70 | } | |
71 | ||
72 | void rt2x00crypto_tx_remove_iv(struct sk_buff *skb, unsigned int iv_len) | |
73 | { | |
74 | struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); | |
75 | unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb); | |
76 | ||
77 | if (unlikely(!iv_len)) | |
78 | return; | |
79 | ||
80 | /* Copy IV/EIV data */ | |
1ce9cdac | 81 | memcpy(skbdesc->iv, skb->data + header_length, iv_len); |
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82 | |
83 | /* Move ieee80211 header */ | |
84 | memmove(skb->data + iv_len, skb->data, header_length); | |
85 | ||
86 | /* Pull buffer to correct size */ | |
87 | skb_pull(skb, iv_len); | |
88 | ||
89 | /* IV/EIV data has officially be stripped */ | |
90 | skbdesc->flags |= FRAME_DESC_IV_STRIPPED; | |
91 | } | |
92 | ||
93 | void rt2x00crypto_tx_insert_iv(struct sk_buff *skb) | |
94 | { | |
95 | struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); | |
96 | unsigned int header_length = ieee80211_get_hdrlen_from_skb(skb); | |
97 | const unsigned int iv_len = | |
1ce9cdac | 98 | ((!!(skbdesc->iv[0])) * 4) + ((!!(skbdesc->iv[1])) * 4); |
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99 | |
100 | if (!(skbdesc->flags & FRAME_DESC_IV_STRIPPED)) | |
101 | return; | |
102 | ||
103 | skb_push(skb, iv_len); | |
104 | ||
105 | /* Move ieee80211 header */ | |
106 | memmove(skb->data, skb->data + iv_len, header_length); | |
107 | ||
108 | /* Copy IV/EIV data */ | |
1ce9cdac | 109 | memcpy(skb->data + header_length, skbdesc->iv, iv_len); |
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110 | |
111 | /* IV/EIV data has returned into the frame */ | |
112 | skbdesc->flags &= ~FRAME_DESC_IV_STRIPPED; | |
113 | } | |
114 | ||
115 | void rt2x00crypto_rx_insert_iv(struct sk_buff *skb, unsigned int align, | |
116 | unsigned int header_length, | |
117 | struct rxdone_entry_desc *rxdesc) | |
118 | { | |
119 | unsigned int payload_len = rxdesc->size - header_length; | |
120 | unsigned int iv_len; | |
121 | unsigned int icv_len; | |
122 | unsigned int transfer = 0; | |
123 | ||
124 | /* | |
125 | * WEP64/WEP128: Provides IV & ICV | |
126 | * TKIP: Provides IV/EIV & ICV | |
127 | * AES: Provies IV/EIV & ICV | |
128 | */ | |
129 | switch (rxdesc->cipher) { | |
130 | case CIPHER_WEP64: | |
131 | case CIPHER_WEP128: | |
132 | iv_len = 4; | |
133 | icv_len = 4; | |
134 | break; | |
135 | case CIPHER_TKIP: | |
136 | iv_len = 8; | |
137 | icv_len = 4; | |
138 | break; | |
139 | case CIPHER_AES: | |
140 | iv_len = 8; | |
141 | icv_len = 8; | |
142 | break; | |
143 | default: | |
144 | /* Unsupport type */ | |
145 | return; | |
146 | } | |
147 | ||
148 | /* | |
149 | * Make room for new data, note that we increase both | |
150 | * headsize and tailsize when required. The tailsize is | |
151 | * only needed when ICV data needs to be inserted and | |
152 | * the padding is smaller then the ICV data. | |
153 | * When alignment requirements is greater then the | |
154 | * ICV data we must trim the skb to the correct size | |
155 | * because we need to remove the extra bytes. | |
156 | */ | |
157 | skb_push(skb, iv_len + align); | |
158 | if (align < icv_len) | |
159 | skb_put(skb, icv_len - align); | |
160 | else if (align > icv_len) | |
161 | skb_trim(skb, rxdesc->size + iv_len + icv_len); | |
162 | ||
163 | /* Move ieee80211 header */ | |
164 | memmove(skb->data + transfer, | |
165 | skb->data + transfer + iv_len + align, | |
166 | header_length); | |
167 | transfer += header_length; | |
168 | ||
1ce9cdac ID |
169 | /* Copy IV/EIV data */ |
170 | memcpy(skb->data + transfer, rxdesc->iv, iv_len); | |
171 | transfer += iv_len; | |
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172 | |
173 | /* Move payload */ | |
174 | if (align) { | |
175 | memmove(skb->data + transfer, | |
176 | skb->data + transfer + align, | |
177 | payload_len); | |
178 | } | |
179 | ||
180 | /* | |
181 | * NOTE: Always count the payload as transfered, | |
182 | * even when alignment was set to zero. This is required | |
183 | * for determining the correct offset for the ICV data. | |
184 | */ | |
185 | transfer += payload_len; | |
186 | ||
1ce9cdac ID |
187 | /* |
188 | * Copy ICV data | |
189 | * AES appends 8 bytes, we can't fill the upper | |
190 | * 4 bytes, but mac80211 doesn't care about what | |
191 | * we provide here anyway and strips it immediately. | |
192 | */ | |
193 | memcpy(skb->data + transfer, &rxdesc->icv, 4); | |
194 | transfer += icv_len; | |
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195 | |
196 | /* IV/EIV/ICV has been inserted into frame */ | |
197 | rxdesc->size = transfer; | |
198 | rxdesc->flags &= ~RX_FLAG_IV_STRIPPED; | |
199 | } |