blob: 2c97912335a90944e04927eb7be8219f361e92e0
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 const __be16 APP_ESCAPE = (__force __be16) 0xffff; |
32 | static const __be32 REF_ESCAPE = (__force __be32) 0xffffffff; |
33 | |
34 | static __be16 t10_pi_crc_fn(void *data, unsigned int len) |
35 | { |
36 | return cpu_to_be16(crc_t10dif(data, len)); |
37 | } |
38 | |
39 | static __be16 t10_pi_ip_fn(void *data, unsigned int len) |
40 | { |
41 | return (__force __be16)ip_compute_csum(data, len); |
42 | } |
43 | |
44 | /* |
45 | * Type 1 and Type 2 protection use the same format: 16 bit guard tag, |
46 | * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref |
47 | * tag. |
48 | */ |
49 | static int t10_pi_generate(struct blk_integrity_iter *iter, csum_fn *fn, |
50 | unsigned int type) |
51 | { |
52 | unsigned int i; |
53 | |
54 | for (i = 0 ; i < iter->data_size ; i += iter->interval) { |
55 | struct t10_pi_tuple *pi = iter->prot_buf; |
56 | |
57 | pi->guard_tag = fn(iter->data_buf, iter->interval); |
58 | pi->app_tag = 0; |
59 | |
60 | if (type == 1) |
61 | pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed)); |
62 | else |
63 | pi->ref_tag = 0; |
64 | |
65 | iter->data_buf += iter->interval; |
66 | iter->prot_buf += sizeof(struct t10_pi_tuple); |
67 | iter->seed++; |
68 | } |
69 | |
70 | return 0; |
71 | } |
72 | |
73 | static int t10_pi_verify(struct blk_integrity_iter *iter, csum_fn *fn, |
74 | unsigned int type) |
75 | { |
76 | unsigned int i; |
77 | |
78 | for (i = 0 ; i < iter->data_size ; i += iter->interval) { |
79 | struct t10_pi_tuple *pi = iter->prot_buf; |
80 | __be16 csum; |
81 | |
82 | switch (type) { |
83 | case 1: |
84 | case 2: |
85 | if (pi->app_tag == APP_ESCAPE) |
86 | goto next; |
87 | |
88 | if (be32_to_cpu(pi->ref_tag) != |
89 | lower_32_bits(iter->seed)) { |
90 | pr_err("%s: ref tag error at location %llu " \ |
91 | "(rcvd %u)\n", iter->disk_name, |
92 | (unsigned long long) |
93 | iter->seed, be32_to_cpu(pi->ref_tag)); |
94 | return -EILSEQ; |
95 | } |
96 | break; |
97 | case 3: |
98 | if (pi->app_tag == APP_ESCAPE && |
99 | pi->ref_tag == REF_ESCAPE) |
100 | goto next; |
101 | break; |
102 | } |
103 | |
104 | csum = fn(iter->data_buf, iter->interval); |
105 | |
106 | if (pi->guard_tag != csum) { |
107 | pr_err("%s: guard tag error at sector %llu " \ |
108 | "(rcvd %04x, want %04x)\n", iter->disk_name, |
109 | (unsigned long long)iter->seed, |
110 | be16_to_cpu(pi->guard_tag), be16_to_cpu(csum)); |
111 | return -EILSEQ; |
112 | } |
113 | |
114 | next: |
115 | iter->data_buf += iter->interval; |
116 | iter->prot_buf += sizeof(struct t10_pi_tuple); |
117 | iter->seed++; |
118 | } |
119 | |
120 | return 0; |
121 | } |
122 | |
123 | static int t10_pi_type1_generate_crc(struct blk_integrity_iter *iter) |
124 | { |
125 | return t10_pi_generate(iter, t10_pi_crc_fn, 1); |
126 | } |
127 | |
128 | static int t10_pi_type1_generate_ip(struct blk_integrity_iter *iter) |
129 | { |
130 | return t10_pi_generate(iter, t10_pi_ip_fn, 1); |
131 | } |
132 | |
133 | static int t10_pi_type1_verify_crc(struct blk_integrity_iter *iter) |
134 | { |
135 | return t10_pi_verify(iter, t10_pi_crc_fn, 1); |
136 | } |
137 | |
138 | static int t10_pi_type1_verify_ip(struct blk_integrity_iter *iter) |
139 | { |
140 | return t10_pi_verify(iter, t10_pi_ip_fn, 1); |
141 | } |
142 | |
143 | static int t10_pi_type3_generate_crc(struct blk_integrity_iter *iter) |
144 | { |
145 | return t10_pi_generate(iter, t10_pi_crc_fn, 3); |
146 | } |
147 | |
148 | static int t10_pi_type3_generate_ip(struct blk_integrity_iter *iter) |
149 | { |
150 | return t10_pi_generate(iter, t10_pi_ip_fn, 3); |
151 | } |
152 | |
153 | static int t10_pi_type3_verify_crc(struct blk_integrity_iter *iter) |
154 | { |
155 | return t10_pi_verify(iter, t10_pi_crc_fn, 3); |
156 | } |
157 | |
158 | static int t10_pi_type3_verify_ip(struct blk_integrity_iter *iter) |
159 | { |
160 | return t10_pi_verify(iter, t10_pi_ip_fn, 3); |
161 | } |
162 | |
163 | struct blk_integrity_profile t10_pi_type1_crc = { |
164 | .name = "T10-DIF-TYPE1-CRC", |
165 | .generate_fn = t10_pi_type1_generate_crc, |
166 | .verify_fn = t10_pi_type1_verify_crc, |
167 | }; |
168 | EXPORT_SYMBOL(t10_pi_type1_crc); |
169 | |
170 | struct blk_integrity_profile t10_pi_type1_ip = { |
171 | .name = "T10-DIF-TYPE1-IP", |
172 | .generate_fn = t10_pi_type1_generate_ip, |
173 | .verify_fn = t10_pi_type1_verify_ip, |
174 | }; |
175 | EXPORT_SYMBOL(t10_pi_type1_ip); |
176 | |
177 | struct blk_integrity_profile t10_pi_type3_crc = { |
178 | .name = "T10-DIF-TYPE3-CRC", |
179 | .generate_fn = t10_pi_type3_generate_crc, |
180 | .verify_fn = t10_pi_type3_verify_crc, |
181 | }; |
182 | EXPORT_SYMBOL(t10_pi_type3_crc); |
183 | |
184 | struct blk_integrity_profile t10_pi_type3_ip = { |
185 | .name = "T10-DIF-TYPE3-IP", |
186 | .generate_fn = t10_pi_type3_generate_ip, |
187 | .verify_fn = t10_pi_type3_verify_ip, |
188 | }; |
189 | EXPORT_SYMBOL(t10_pi_type3_ip); |
190 |