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); 198