Martin K. Petersen | 2341c2f8 | 2014-09-26 19:20:07 -0400 | [diff] [blame] | 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 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 | .tuple_size = sizeof(struct t10_pi_tuple), |
| 168 | .tag_size = 0, |
| 169 | }; |
| 170 | EXPORT_SYMBOL(t10_pi_type1_crc); |
| 171 | |
| 172 | struct blk_integrity t10_pi_type1_ip = { |
| 173 | .name = "T10-DIF-TYPE1-IP", |
| 174 | .generate_fn = t10_pi_type1_generate_ip, |
| 175 | .verify_fn = t10_pi_type1_verify_ip, |
| 176 | .tuple_size = sizeof(struct t10_pi_tuple), |
| 177 | .tag_size = 0, |
| 178 | }; |
| 179 | EXPORT_SYMBOL(t10_pi_type1_ip); |
| 180 | |
| 181 | struct blk_integrity t10_pi_type3_crc = { |
| 182 | .name = "T10-DIF-TYPE3-CRC", |
| 183 | .generate_fn = t10_pi_type3_generate_crc, |
| 184 | .verify_fn = t10_pi_type3_verify_crc, |
| 185 | .tuple_size = sizeof(struct t10_pi_tuple), |
| 186 | .tag_size = 0, |
| 187 | }; |
| 188 | EXPORT_SYMBOL(t10_pi_type3_crc); |
| 189 | |
| 190 | struct blk_integrity t10_pi_type3_ip = { |
| 191 | .name = "T10-DIF-TYPE3-IP", |
| 192 | .generate_fn = t10_pi_type3_generate_ip, |
| 193 | .verify_fn = t10_pi_type3_verify_ip, |
| 194 | .tuple_size = sizeof(struct t10_pi_tuple), |
| 195 | .tag_size = 0, |
| 196 | }; |
| 197 | EXPORT_SYMBOL(t10_pi_type3_ip); |