1/* Orinoco MIC helpers
 2 *
 3 * See copyright notice in main.c
 4 */
 5#include <linux/kernel.h>
 6#include <linux/string.h>
 7#include <linux/if_ether.h>
 8#include <linux/scatterlist.h>
 9#include <crypto/hash.h>
10
11#include "orinoco.h"
12#include "mic.h"
13
14/********************************************************************/
15/* Michael MIC crypto setup                                         */
16/********************************************************************/
17int orinoco_mic_init(struct orinoco_private *priv)
18{
19	priv->tx_tfm_mic = crypto_alloc_ahash("michael_mic", 0,
20					      CRYPTO_ALG_ASYNC);
21	if (IS_ERR(priv->tx_tfm_mic)) {
22		printk(KERN_DEBUG "orinoco_mic_init: could not allocate "
23		       "crypto API michael_mic\n");
24		priv->tx_tfm_mic = NULL;
25		return -ENOMEM;
26	}
27
28	priv->rx_tfm_mic = crypto_alloc_ahash("michael_mic", 0,
29					      CRYPTO_ALG_ASYNC);
30	if (IS_ERR(priv->rx_tfm_mic)) {
31		printk(KERN_DEBUG "orinoco_mic_init: could not allocate "
32		       "crypto API michael_mic\n");
33		priv->rx_tfm_mic = NULL;
34		return -ENOMEM;
35	}
36
37	return 0;
38}
39
40void orinoco_mic_free(struct orinoco_private *priv)
41{
42	if (priv->tx_tfm_mic)
43		crypto_free_ahash(priv->tx_tfm_mic);
44	if (priv->rx_tfm_mic)
45		crypto_free_ahash(priv->rx_tfm_mic);
46}
47
48int orinoco_mic(struct crypto_ahash *tfm_michael, u8 *key,
49		u8 *da, u8 *sa, u8 priority,
50		u8 *data, size_t data_len, u8 *mic)
51{
52	AHASH_REQUEST_ON_STACK(req, tfm_michael);
53	struct scatterlist sg[2];
54	u8 hdr[ETH_HLEN + 2]; /* size of header + padding */
55	int err;
56
57	if (tfm_michael == NULL) {
58		printk(KERN_WARNING "orinoco_mic: tfm_michael == NULL\n");
59		return -1;
60	}
61
62	/* Copy header into buffer. We need the padding on the end zeroed */
63	memcpy(&hdr[0], da, ETH_ALEN);
64	memcpy(&hdr[ETH_ALEN], sa, ETH_ALEN);
65	hdr[ETH_ALEN * 2] = priority;
66	hdr[ETH_ALEN * 2 + 1] = 0;
67	hdr[ETH_ALEN * 2 + 2] = 0;
68	hdr[ETH_ALEN * 2 + 3] = 0;
69
70	/* Use scatter gather to MIC header and data in one go */
71	sg_init_table(sg, 2);
72	sg_set_buf(&sg[0], hdr, sizeof(hdr));
73	sg_set_buf(&sg[1], data, data_len);
74
75	if (crypto_ahash_setkey(tfm_michael, key, MIC_KEYLEN))
76		return -1;
77
78	ahash_request_set_tfm(req, tfm_michael);
79	ahash_request_set_callback(req, 0, NULL, NULL);
80	ahash_request_set_crypt(req, sg, mic, data_len + sizeof(hdr));
81	err = crypto_ahash_digest(req);
82	ahash_request_zero(req);
83	return err;
84}