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
t10_pi_crc_fn(void * data,unsigned int len)34 static __be16 t10_pi_crc_fn(void *data, unsigned int len)
35 {
36 return cpu_to_be16(crc_t10dif(data, len));
37 }
38
t10_pi_ip_fn(void * data,unsigned int len)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 */
t10_pi_generate(struct blk_integrity_iter * iter,csum_fn * fn,unsigned int type)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
t10_pi_verify(struct blk_integrity_iter * iter,csum_fn * fn,unsigned int type)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
t10_pi_type1_generate_crc(struct blk_integrity_iter * iter)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
t10_pi_type1_generate_ip(struct blk_integrity_iter * iter)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
t10_pi_type1_verify_crc(struct blk_integrity_iter * iter)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
t10_pi_type1_verify_ip(struct blk_integrity_iter * iter)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
t10_pi_type3_generate_crc(struct blk_integrity_iter * iter)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
t10_pi_type3_generate_ip(struct blk_integrity_iter * iter)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
t10_pi_type3_verify_crc(struct blk_integrity_iter * iter)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
t10_pi_type3_verify_ip(struct blk_integrity_iter * iter)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