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); 187