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1 | /* | |
2 | * t10_pi.c - Functions for generating and verifying T10 Protection | |
3 | * Information. | |
4 | * | |
5 | * Copyright (C) 2007, 2008, 2014 Oracle Corporation | |
6 | * Written by: Martin K. Petersen <martin.petersen@oracle.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License version | |
10 | * 2 as published by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, but | |
13 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; see the file COPYING. If not, write to | |
19 | * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, | |
20 | * USA. | |
21 | * | |
22 | */ | |
23 | ||
24 | #include <linux/t10-pi.h> | |
25 | #include <linux/blkdev.h> | |
26 | #include <linux/crc-t10dif.h> | |
27 | #include <net/checksum.h> | |
28 | ||
29 | typedef __be16 (csum_fn) (void *, unsigned int); | |
30 | ||
31 | static __be16 t10_pi_crc_fn(void *data, unsigned int len) | |
32 | { | |
33 | return cpu_to_be16(crc_t10dif(data, len)); | |
34 | } | |
35 | ||
36 | static __be16 t10_pi_ip_fn(void *data, unsigned int len) | |
37 | { | |
38 | return (__force __be16)ip_compute_csum(data, len); | |
39 | } | |
40 | ||
41 | /* | |
42 | * Type 1 and Type 2 protection use the same format: 16 bit guard tag, | |
43 | * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref | |
44 | * tag. | |
45 | */ | |
46 | static blk_status_t t10_pi_generate(struct blk_integrity_iter *iter, | |
47 | csum_fn *fn, unsigned int type) | |
48 | { | |
49 | unsigned int i; | |
50 | ||
51 | for (i = 0 ; i < iter->data_size ; i += iter->interval) { | |
52 | struct t10_pi_tuple *pi = iter->prot_buf; | |
53 | ||
54 | pi->guard_tag = fn(iter->data_buf, iter->interval); | |
55 | pi->app_tag = 0; | |
56 | ||
57 | if (type == 1) | |
58 | pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed)); | |
59 | else | |
60 | pi->ref_tag = 0; | |
61 | ||
62 | iter->data_buf += iter->interval; | |
63 | iter->prot_buf += sizeof(struct t10_pi_tuple); | |
64 | iter->seed++; | |
65 | } | |
66 | ||
67 | return BLK_STS_OK; | |
68 | } | |
69 | ||
70 | static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter, | |
71 | csum_fn *fn, unsigned int type) | |
72 | { | |
73 | unsigned int i; | |
74 | ||
75 | for (i = 0 ; i < iter->data_size ; i += iter->interval) { | |
76 | struct t10_pi_tuple *pi = iter->prot_buf; | |
77 | __be16 csum; | |
78 | ||
79 | switch (type) { | |
80 | case 1: | |
81 | case 2: | |
82 | if (pi->app_tag == T10_PI_APP_ESCAPE) | |
83 | goto next; | |
84 | ||
85 | if (be32_to_cpu(pi->ref_tag) != | |
86 | lower_32_bits(iter->seed)) { | |
87 | pr_err("%s: ref tag error at location %llu " \ | |
88 | "(rcvd %u)\n", iter->disk_name, | |
89 | (unsigned long long) | |
90 | iter->seed, be32_to_cpu(pi->ref_tag)); | |
91 | return BLK_STS_PROTECTION; | |
92 | } | |
93 | break; | |
94 | case 3: | |
95 | if (pi->app_tag == T10_PI_APP_ESCAPE && | |
96 | pi->ref_tag == T10_PI_REF_ESCAPE) | |
97 | goto next; | |
98 | break; | |
99 | } | |
100 | ||
101 | csum = fn(iter->data_buf, iter->interval); | |
102 | ||
103 | if (pi->guard_tag != csum) { | |
104 | pr_err("%s: guard tag error at sector %llu " \ | |
105 | "(rcvd %04x, want %04x)\n", iter->disk_name, | |
106 | (unsigned long long)iter->seed, | |
107 | be16_to_cpu(pi->guard_tag), be16_to_cpu(csum)); | |
108 | return BLK_STS_PROTECTION; | |
109 | } | |
110 | ||
111 | next: | |
112 | iter->data_buf += iter->interval; | |
113 | iter->prot_buf += sizeof(struct t10_pi_tuple); | |
114 | iter->seed++; | |
115 | } | |
116 | ||
117 | return BLK_STS_OK; | |
118 | } | |
119 | ||
120 | static blk_status_t t10_pi_type1_generate_crc(struct blk_integrity_iter *iter) | |
121 | { | |
122 | return t10_pi_generate(iter, t10_pi_crc_fn, 1); | |
123 | } | |
124 | ||
125 | static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter) | |
126 | { | |
127 | return t10_pi_generate(iter, t10_pi_ip_fn, 1); | |
128 | } | |
129 | ||
130 | static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter) | |
131 | { | |
132 | return t10_pi_verify(iter, t10_pi_crc_fn, 1); | |
133 | } | |
134 | ||
135 | static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter) | |
136 | { | |
137 | return t10_pi_verify(iter, t10_pi_ip_fn, 1); | |
138 | } | |
139 | ||
140 | static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter) | |
141 | { | |
142 | return t10_pi_generate(iter, t10_pi_crc_fn, 3); | |
143 | } | |
144 | ||
145 | static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter) | |
146 | { | |
147 | return t10_pi_generate(iter, t10_pi_ip_fn, 3); | |
148 | } | |
149 | ||
150 | static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter) | |
151 | { | |
152 | return t10_pi_verify(iter, t10_pi_crc_fn, 3); | |
153 | } | |
154 | ||
155 | static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter) | |
156 | { | |
157 | return t10_pi_verify(iter, t10_pi_ip_fn, 3); | |
158 | } | |
159 | ||
160 | const struct blk_integrity_profile t10_pi_type1_crc = { | |
161 | .name = "T10-DIF-TYPE1-CRC", | |
162 | .generate_fn = t10_pi_type1_generate_crc, | |
163 | .verify_fn = t10_pi_type1_verify_crc, | |
164 | }; | |
165 | EXPORT_SYMBOL(t10_pi_type1_crc); | |
166 | ||
167 | const struct blk_integrity_profile t10_pi_type1_ip = { | |
168 | .name = "T10-DIF-TYPE1-IP", | |
169 | .generate_fn = t10_pi_type1_generate_ip, | |
170 | .verify_fn = t10_pi_type1_verify_ip, | |
171 | }; | |
172 | EXPORT_SYMBOL(t10_pi_type1_ip); | |
173 | ||
174 | const struct blk_integrity_profile t10_pi_type3_crc = { | |
175 | .name = "T10-DIF-TYPE3-CRC", | |
176 | .generate_fn = t10_pi_type3_generate_crc, | |
177 | .verify_fn = t10_pi_type3_verify_crc, | |
178 | }; | |
179 | EXPORT_SYMBOL(t10_pi_type3_crc); | |
180 | ||
181 | const struct blk_integrity_profile t10_pi_type3_ip = { | |
182 | .name = "T10-DIF-TYPE3-IP", | |
183 | .generate_fn = t10_pi_type3_generate_ip, | |
184 | .verify_fn = t10_pi_type3_verify_ip, | |
185 | }; | |
186 | EXPORT_SYMBOL(t10_pi_type3_ip); |