xref: /freebsd/sys/net80211/ieee80211_crypto.h (revision 6af83ee0d2941d18880b6aaa2b4facd1d30c6106)
1 /*-
2  * Copyright (c) 2001 Atsushi Onoe
3  * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * Alternatively, this software may be distributed under the terms of the
18  * GNU General Public License ("GPL") version 2 as published by the Free
19  * Software Foundation.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  *
32  * $FreeBSD$
33  */
34 #ifndef _NET80211_IEEE80211_CRYPTO_H_
35 #define _NET80211_IEEE80211_CRYPTO_H_
36 
37 /*
38  * 802.11 protocol crypto-related definitions.
39  */
40 #define	IEEE80211_KEYBUF_SIZE	16
41 #define	IEEE80211_MICBUF_SIZE	(8+8)	/* space for both tx+rx keys */
42 
43 /*
44  * Old WEP-style key.  Deprecated.
45  */
46 struct ieee80211_wepkey {
47 	u_int		wk_len;		/* key length in bytes */
48 	u_int8_t	wk_key[IEEE80211_KEYBUF_SIZE];
49 };
50 
51 struct ieee80211_cipher;
52 
53 /*
54  * Crypto key state.  There is sufficient room for all supported
55  * ciphers (see below).  The underlying ciphers are handled
56  * separately through loadable cipher modules that register with
57  * the generic crypto support.  A key has a reference to an instance
58  * of the cipher; any per-key state is hung off wk_private by the
59  * cipher when it is attached.  Ciphers are automatically called
60  * to detach and cleanup any such state when the key is deleted.
61  *
62  * The generic crypto support handles encap/decap of cipher-related
63  * frame contents for both hardware- and software-based implementations.
64  * A key requiring software crypto support is automatically flagged and
65  * the cipher is expected to honor this and do the necessary work.
66  * Ciphers such as TKIP may also support mixed hardware/software
67  * encrypt/decrypt and MIC processing.
68  */
69 /* XXX need key index typedef */
70 /* XXX pack better? */
71 /* XXX 48-bit rsc/tsc */
72 struct ieee80211_key {
73 	u_int8_t	wk_keylen;	/* key length in bytes */
74 	u_int8_t	wk_flags;
75 #define	IEEE80211_KEY_XMIT	0x01	/* key used for xmit */
76 #define	IEEE80211_KEY_RECV	0x02	/* key used for recv */
77 #define	IEEE80211_KEY_SWCRYPT	0x04	/* host-based encrypt/decrypt */
78 #define	IEEE80211_KEY_SWMIC	0x08	/* host-based enmic/demic */
79 	u_int16_t	wk_keyix;	/* key index */
80 	u_int8_t	wk_key[IEEE80211_KEYBUF_SIZE+IEEE80211_MICBUF_SIZE];
81 #define	wk_txmic	wk_key+IEEE80211_KEYBUF_SIZE+0	/* XXX can't () right */
82 #define	wk_rxmic	wk_key+IEEE80211_KEYBUF_SIZE+8	/* XXX can't () right */
83 	u_int64_t	wk_keyrsc;	/* key receive sequence counter */
84 	u_int64_t	wk_keytsc;	/* key transmit sequence counter */
85 	const struct ieee80211_cipher *wk_cipher;
86 	void		*wk_private;	/* private cipher state */
87 };
88 
89 /*
90  * NB: these values are ordered carefully; there are lots of
91  * of implications in any reordering.  In particular beware
92  * that 4 is not used to avoid conflicting with IEEE80211_F_PRIVACY.
93  */
94 #define	IEEE80211_CIPHER_WEP		0
95 #define	IEEE80211_CIPHER_TKIP		1
96 #define	IEEE80211_CIPHER_AES_OCB	2
97 #define	IEEE80211_CIPHER_AES_CCM	3
98 #define	IEEE80211_CIPHER_CKIP		5
99 #define	IEEE80211_CIPHER_NONE		6	/* pseudo value */
100 
101 #define	IEEE80211_CIPHER_MAX		(IEEE80211_CIPHER_NONE+1)
102 
103 #define	IEEE80211_KEYIX_NONE	((u_int16_t) -1)
104 
105 #if defined(__KERNEL__) || defined(_KERNEL)
106 
107 struct ieee80211com;
108 struct ieee80211_node;
109 struct mbuf;
110 
111 /*
112  * Crypto state kept in each ieee80211com.  Some of this
113  * can/should be shared when virtual AP's are supported.
114  *
115  * XXX save reference to ieee80211com to properly encapsulate state.
116  * XXX split out crypto capabilities from ic_caps
117  */
118 struct ieee80211_crypto_state {
119 	struct ieee80211_key	cs_nw_keys[IEEE80211_WEP_NKID];
120 	u_int16_t		cs_def_txkey;	/* default/group tx key index */
121 
122 	int			(*cs_key_alloc)(struct ieee80211com *,
123 					const struct ieee80211_key *);
124 	int			(*cs_key_delete)(struct ieee80211com *,
125 					const struct ieee80211_key *);
126 	int			(*cs_key_set)(struct ieee80211com *,
127 					const struct ieee80211_key *,
128 					const u_int8_t mac[IEEE80211_ADDR_LEN]);
129 	void			(*cs_key_update_begin)(struct ieee80211com *);
130 	void			(*cs_key_update_end)(struct ieee80211com *);
131 };
132 
133 extern	void ieee80211_crypto_attach(struct ieee80211com *);
134 extern	void ieee80211_crypto_detach(struct ieee80211com *);
135 extern	int ieee80211_crypto_newkey(struct ieee80211com *,
136 		int cipher, struct ieee80211_key *);
137 extern	int ieee80211_crypto_delkey(struct ieee80211com *,
138 		struct ieee80211_key *);
139 extern	int ieee80211_crypto_setkey(struct ieee80211com *,
140 		struct ieee80211_key *, const u_int8_t macaddr[IEEE80211_ADDR_LEN]);
141 extern	void ieee80211_crypto_delglobalkeys(struct ieee80211com *);
142 
143 /*
144  * Template for a supported cipher.  Ciphers register with the
145  * crypto code and are typically loaded as separate modules
146  * (the null cipher is always present).
147  * XXX may need refcnts
148  */
149 struct ieee80211_cipher {
150 	const char *ic_name;		/* printable name */
151 	u_int	ic_cipher;		/* IEEE80211_CIPHER_* */
152 	u_int	ic_header;		/* size of privacy header (bytes) */
153 	u_int	ic_trailer;		/* size of privacy trailer (bytes) */
154 	u_int	ic_miclen;		/* size of mic trailer (bytes) */
155 	void*	(*ic_attach)(struct ieee80211com *, struct ieee80211_key *);
156 	void	(*ic_detach)(struct ieee80211_key *);
157 	int	(*ic_setkey)(struct ieee80211_key *);
158 	int	(*ic_encap)(struct ieee80211_key *, struct mbuf *,
159 			u_int8_t keyid);
160 	int	(*ic_decap)(struct ieee80211_key *, struct mbuf *);
161 	int	(*ic_enmic)(struct ieee80211_key *, struct mbuf *);
162 	int	(*ic_demic)(struct ieee80211_key *, struct mbuf *);
163 };
164 extern	const struct ieee80211_cipher ieee80211_cipher_none;
165 
166 extern	void ieee80211_crypto_register(const struct ieee80211_cipher *);
167 extern	void ieee80211_crypto_unregister(const struct ieee80211_cipher *);
168 extern	int ieee80211_crypto_available(u_int cipher);
169 
170 extern	struct ieee80211_key *ieee80211_crypto_encap(struct ieee80211com *,
171 		struct ieee80211_node *, struct mbuf *);
172 extern	struct ieee80211_key *ieee80211_crypto_decap(struct ieee80211com *,
173 		struct ieee80211_node *, struct mbuf *);
174 
175 /*
176  * Check and remove any MIC.
177  */
178 static __inline int
179 ieee80211_crypto_demic(struct ieee80211com *ic, struct ieee80211_key *k,
180 	struct mbuf *m)
181 {
182 	const struct ieee80211_cipher *cip = k->wk_cipher;
183 	return (cip->ic_miclen > 0 ? cip->ic_demic(k, m) : 1);
184 }
185 
186 /*
187  * Add any MIC.
188  */
189 static __inline int
190 ieee80211_crypto_enmic(struct ieee80211com *ic,
191 	struct ieee80211_key *k, struct mbuf *m)
192 {
193 	const struct ieee80211_cipher *cip = k->wk_cipher;
194 	return (cip->ic_miclen > 0 ? cip->ic_enmic(k, m) : 1);
195 }
196 
197 /*
198  * Reset key state to an unused state.  The crypto
199  * key allocation mechanism insures other state (e.g.
200  * key data) is properly setup before a key is used.
201  */
202 static __inline void
203 ieee80211_crypto_resetkey(struct ieee80211com *ic,
204 	struct ieee80211_key *k, u_int16_t ix)
205 {
206 	k->wk_cipher = &ieee80211_cipher_none;;
207 	k->wk_private = k->wk_cipher->ic_attach(ic, k);
208 	k->wk_keyix = ix;
209 	k->wk_flags = IEEE80211_KEY_XMIT | IEEE80211_KEY_RECV;
210 }
211 
212 /*
213  * Crypt-related notification methods.
214  */
215 extern	void ieee80211_notify_replay_failure(struct ieee80211com *,
216 		const struct ieee80211_frame *, const struct ieee80211_key *,
217 		u_int64_t rsc);
218 extern	void ieee80211_notify_michael_failure(struct ieee80211com *,
219 		const struct ieee80211_frame *, u_int keyix);
220 #endif /* defined(__KERNEL__) || defined(_KERNEL) */
221 #endif /* _NET80211_IEEE80211_CRYPTO_H_ */
222