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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * T10 Data Integrity Field CRC16 calculation
4 *
5 * Copyright (c) 2007 Oracle Corporation. All rights reserved.
6 * Written by Martin K. Petersen <martin.petersen@oracle.com>
7 */
8
9#include <linux/types.h>
10#include <linux/module.h>
11#include <linux/crc-t10dif.h>
12#include <linux/err.h>
13#include <linux/init.h>
14#include <crypto/hash.h>
15#include <crypto/algapi.h>
16#include <linux/static_key.h>
17#include <linux/notifier.h>
18
19static struct crypto_shash __rcu *crct10dif_tfm;
20static DEFINE_STATIC_KEY_TRUE(crct10dif_fallback);
21static DEFINE_MUTEX(crc_t10dif_mutex);
22static struct work_struct crct10dif_rehash_work;
23
24static int crc_t10dif_notify(struct notifier_block *self, unsigned long val, void *data)
25{
26 struct crypto_alg *alg = data;
27
28 if (val != CRYPTO_MSG_ALG_LOADED ||
29 strcmp(alg->cra_name, CRC_T10DIF_STRING))
30 return NOTIFY_DONE;
31
32 schedule_work(&crct10dif_rehash_work);
33 return NOTIFY_OK;
34}
35
36static void crc_t10dif_rehash(struct work_struct *work)
37{
38 struct crypto_shash *new, *old;
39
40 mutex_lock(&crc_t10dif_mutex);
41 old = rcu_dereference_protected(crct10dif_tfm,
42 lockdep_is_held(&crc_t10dif_mutex));
43 new = crypto_alloc_shash(CRC_T10DIF_STRING, 0, 0);
44 if (IS_ERR(new)) {
45 mutex_unlock(&crc_t10dif_mutex);
46 return;
47 }
48 rcu_assign_pointer(crct10dif_tfm, new);
49 mutex_unlock(&crc_t10dif_mutex);
50
51 if (old) {
52 synchronize_rcu();
53 crypto_free_shash(old);
54 } else {
55 static_branch_disable(&crct10dif_fallback);
56 }
57}
58
59static struct notifier_block crc_t10dif_nb = {
60 .notifier_call = crc_t10dif_notify,
61};
62
63__u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len)
64{
65 struct {
66 struct shash_desc shash;
67 __u16 crc;
68 } desc;
69 int err;
70
71 if (static_branch_unlikely(&crct10dif_fallback))
72 return crc_t10dif_generic(crc, buffer, len);
73
74 rcu_read_lock();
75 desc.shash.tfm = rcu_dereference(crct10dif_tfm);
76 desc.crc = crc;
77 err = crypto_shash_update(&desc.shash, buffer, len);
78 rcu_read_unlock();
79
80 BUG_ON(err);
81
82 return desc.crc;
83}
84EXPORT_SYMBOL(crc_t10dif_update);
85
86__u16 crc_t10dif(const unsigned char *buffer, size_t len)
87{
88 return crc_t10dif_update(0, buffer, len);
89}
90EXPORT_SYMBOL(crc_t10dif);
91
92static int __init crc_t10dif_mod_init(void)
93{
94 INIT_WORK(&crct10dif_rehash_work, crc_t10dif_rehash);
95 crypto_register_notifier(&crc_t10dif_nb);
96 crc_t10dif_rehash(&crct10dif_rehash_work);
97 return 0;
98}
99
100static void __exit crc_t10dif_mod_fini(void)
101{
102 crypto_unregister_notifier(&crc_t10dif_nb);
103 cancel_work_sync(&crct10dif_rehash_work);
104 crypto_free_shash(rcu_dereference_protected(crct10dif_tfm, 1));
105}
106
107module_init(crc_t10dif_mod_init);
108module_exit(crc_t10dif_mod_fini);
109
110static int crc_t10dif_transform_show(char *buffer, const struct kernel_param *kp)
111{
112 struct crypto_shash *tfm;
113 int len;
114
115 if (static_branch_unlikely(&crct10dif_fallback))
116 return sprintf(buffer, "fallback\n");
117
118 rcu_read_lock();
119 tfm = rcu_dereference(crct10dif_tfm);
120 len = snprintf(buffer, PAGE_SIZE, "%s\n",
121 crypto_shash_driver_name(tfm));
122 rcu_read_unlock();
123
124 return len;
125}
126
127module_param_call(transform, NULL, crc_t10dif_transform_show, NULL, 0444);
128
129MODULE_DESCRIPTION("T10 DIF CRC calculation (library API)");
130MODULE_LICENSE("GPL");
131MODULE_SOFTDEP("pre: crct10dif");
1/*
2 * T10 Data Integrity Field CRC16 calculation
3 *
4 * Copyright (c) 2007 Oracle Corporation. All rights reserved.
5 * Written by Martin K. Petersen <martin.petersen@oracle.com>
6 *
7 * This source code is licensed under the GNU General Public License,
8 * Version 2. See the file COPYING for more details.
9 */
10
11#include <linux/types.h>
12#include <linux/module.h>
13#include <linux/crc-t10dif.h>
14
15/* Table generated using the following polynomium:
16 * x^16 + x^15 + x^11 + x^9 + x^8 + x^7 + x^5 + x^4 + x^2 + x + 1
17 * gt: 0x8bb7
18 */
19static const __u16 t10_dif_crc_table[256] = {
20 0x0000, 0x8BB7, 0x9CD9, 0x176E, 0xB205, 0x39B2, 0x2EDC, 0xA56B,
21 0xEFBD, 0x640A, 0x7364, 0xF8D3, 0x5DB8, 0xD60F, 0xC161, 0x4AD6,
22 0x54CD, 0xDF7A, 0xC814, 0x43A3, 0xE6C8, 0x6D7F, 0x7A11, 0xF1A6,
23 0xBB70, 0x30C7, 0x27A9, 0xAC1E, 0x0975, 0x82C2, 0x95AC, 0x1E1B,
24 0xA99A, 0x222D, 0x3543, 0xBEF4, 0x1B9F, 0x9028, 0x8746, 0x0CF1,
25 0x4627, 0xCD90, 0xDAFE, 0x5149, 0xF422, 0x7F95, 0x68FB, 0xE34C,
26 0xFD57, 0x76E0, 0x618E, 0xEA39, 0x4F52, 0xC4E5, 0xD38B, 0x583C,
27 0x12EA, 0x995D, 0x8E33, 0x0584, 0xA0EF, 0x2B58, 0x3C36, 0xB781,
28 0xD883, 0x5334, 0x445A, 0xCFED, 0x6A86, 0xE131, 0xF65F, 0x7DE8,
29 0x373E, 0xBC89, 0xABE7, 0x2050, 0x853B, 0x0E8C, 0x19E2, 0x9255,
30 0x8C4E, 0x07F9, 0x1097, 0x9B20, 0x3E4B, 0xB5FC, 0xA292, 0x2925,
31 0x63F3, 0xE844, 0xFF2A, 0x749D, 0xD1F6, 0x5A41, 0x4D2F, 0xC698,
32 0x7119, 0xFAAE, 0xEDC0, 0x6677, 0xC31C, 0x48AB, 0x5FC5, 0xD472,
33 0x9EA4, 0x1513, 0x027D, 0x89CA, 0x2CA1, 0xA716, 0xB078, 0x3BCF,
34 0x25D4, 0xAE63, 0xB90D, 0x32BA, 0x97D1, 0x1C66, 0x0B08, 0x80BF,
35 0xCA69, 0x41DE, 0x56B0, 0xDD07, 0x786C, 0xF3DB, 0xE4B5, 0x6F02,
36 0x3AB1, 0xB106, 0xA668, 0x2DDF, 0x88B4, 0x0303, 0x146D, 0x9FDA,
37 0xD50C, 0x5EBB, 0x49D5, 0xC262, 0x6709, 0xECBE, 0xFBD0, 0x7067,
38 0x6E7C, 0xE5CB, 0xF2A5, 0x7912, 0xDC79, 0x57CE, 0x40A0, 0xCB17,
39 0x81C1, 0x0A76, 0x1D18, 0x96AF, 0x33C4, 0xB873, 0xAF1D, 0x24AA,
40 0x932B, 0x189C, 0x0FF2, 0x8445, 0x212E, 0xAA99, 0xBDF7, 0x3640,
41 0x7C96, 0xF721, 0xE04F, 0x6BF8, 0xCE93, 0x4524, 0x524A, 0xD9FD,
42 0xC7E6, 0x4C51, 0x5B3F, 0xD088, 0x75E3, 0xFE54, 0xE93A, 0x628D,
43 0x285B, 0xA3EC, 0xB482, 0x3F35, 0x9A5E, 0x11E9, 0x0687, 0x8D30,
44 0xE232, 0x6985, 0x7EEB, 0xF55C, 0x5037, 0xDB80, 0xCCEE, 0x4759,
45 0x0D8F, 0x8638, 0x9156, 0x1AE1, 0xBF8A, 0x343D, 0x2353, 0xA8E4,
46 0xB6FF, 0x3D48, 0x2A26, 0xA191, 0x04FA, 0x8F4D, 0x9823, 0x1394,
47 0x5942, 0xD2F5, 0xC59B, 0x4E2C, 0xEB47, 0x60F0, 0x779E, 0xFC29,
48 0x4BA8, 0xC01F, 0xD771, 0x5CC6, 0xF9AD, 0x721A, 0x6574, 0xEEC3,
49 0xA415, 0x2FA2, 0x38CC, 0xB37B, 0x1610, 0x9DA7, 0x8AC9, 0x017E,
50 0x1F65, 0x94D2, 0x83BC, 0x080B, 0xAD60, 0x26D7, 0x31B9, 0xBA0E,
51 0xF0D8, 0x7B6F, 0x6C01, 0xE7B6, 0x42DD, 0xC96A, 0xDE04, 0x55B3
52};
53
54__u16 crc_t10dif(const unsigned char *buffer, size_t len)
55{
56 __u16 crc = 0;
57 unsigned int i;
58
59 for (i = 0 ; i < len ; i++)
60 crc = (crc << 8) ^ t10_dif_crc_table[((crc >> 8) ^ buffer[i]) & 0xff];
61
62 return crc;
63}
64EXPORT_SYMBOL(crc_t10dif);
65
66MODULE_DESCRIPTION("T10 DIF CRC calculation");
67MODULE_LICENSE("GPL");