/* * t10_pi.c - Functions for generating and verifying T10 Protection * Information. * * Copyright (C) 2007, 2008, 2014 Oracle Corporation * Written by: Martin K. Petersen <martin.petersen@oracle.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; see the file COPYING. If not, write to * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, * USA. * */ #include <linux/t10-pi.h> #include <linux/blkdev.h> #include <linux/crc-t10dif.h> #include <net/checksum.h> typedef __be16 (csum_fn) (void *, unsigned int); static const __be16 APP_ESCAPE = (__force __be16) 0xffff; static const __be32 REF_ESCAPE = (__force __be32) 0xffffffff; static __be16 t10_pi_crc_fn(void *data, unsigned int len) { return cpu_to_be16(crc_t10dif(data, len)); } static __be16 t10_pi_ip_fn(void *data, unsigned int len) { return (__force __be16)ip_compute_csum(data, len); } /* * Type 1 and Type 2 protection use the same format: 16 bit guard tag, * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref * tag. */ static int t10_pi_generate(struct blk_integrity_iter *iter, csum_fn *fn, unsigned int type) { unsigned int i; for (i = 0 ; i < iter->data_size ; i += iter->interval) { struct t10_pi_tuple *pi = iter->prot_buf; pi->guard_tag = fn(iter->data_buf, iter->interval); pi->app_tag = 0; if (type == 1) pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed)); else pi->ref_tag = 0; iter->data_buf += iter->interval; iter->prot_buf += sizeof(struct t10_pi_tuple); iter->seed++; } return 0; } static int t10_pi_verify(struct blk_integrity_iter *iter, csum_fn *fn, unsigned int type) { unsigned int i; for (i = 0 ; i < iter->data_size ; i += iter->interval) { struct t10_pi_tuple *pi = iter->prot_buf; __be16 csum; switch (type) { case 1: case 2: if (pi->app_tag == APP_ESCAPE) goto next; if (be32_to_cpu(pi->ref_tag) != lower_32_bits(iter->seed)) { pr_err("%s: ref tag error at location %llu " \ "(rcvd %u)\n", iter->disk_name, (unsigned long long) iter->seed, be32_to_cpu(pi->ref_tag)); return -EILSEQ; } break; case 3: if (pi->app_tag == APP_ESCAPE && pi->ref_tag == REF_ESCAPE) goto next; break; } csum = fn(iter->data_buf, iter->interval); if (pi->guard_tag != csum) { pr_err("%s: guard tag error at sector %llu " \ "(rcvd %04x, want %04x)\n", iter->disk_name, (unsigned long long)iter->seed, be16_to_cpu(pi->guard_tag), be16_to_cpu(csum)); return -EILSEQ; } next: iter->data_buf += iter->interval; iter->prot_buf += sizeof(struct t10_pi_tuple); iter->seed++; } return 0; } static int t10_pi_type1_generate_crc(struct blk_integrity_iter *iter) { return t10_pi_generate(iter, t10_pi_crc_fn, 1); } static int t10_pi_type1_generate_ip(struct blk_integrity_iter *iter) { return t10_pi_generate(iter, t10_pi_ip_fn, 1); } static int t10_pi_type1_verify_crc(struct blk_integrity_iter *iter) { return t10_pi_verify(iter, t10_pi_crc_fn, 1); } static int t10_pi_type1_verify_ip(struct blk_integrity_iter *iter) { return t10_pi_verify(iter, t10_pi_ip_fn, 1); } static int t10_pi_type3_generate_crc(struct blk_integrity_iter *iter) { return t10_pi_generate(iter, t10_pi_crc_fn, 3); } static int t10_pi_type3_generate_ip(struct blk_integrity_iter *iter) { return t10_pi_generate(iter, t10_pi_ip_fn, 3); } static int t10_pi_type3_verify_crc(struct blk_integrity_iter *iter) { return t10_pi_verify(iter, t10_pi_crc_fn, 3); } static int t10_pi_type3_verify_ip(struct blk_integrity_iter *iter) { return t10_pi_verify(iter, t10_pi_ip_fn, 3); } struct blk_integrity t10_pi_type1_crc = { .name = "T10-DIF-TYPE1-CRC", .generate_fn = t10_pi_type1_generate_crc, .verify_fn = t10_pi_type1_verify_crc, .tuple_size = sizeof(struct t10_pi_tuple), .tag_size = 0, }; EXPORT_SYMBOL(t10_pi_type1_crc); struct blk_integrity t10_pi_type1_ip = { .name = "T10-DIF-TYPE1-IP", .generate_fn = t10_pi_type1_generate_ip, .verify_fn = t10_pi_type1_verify_ip, .tuple_size = sizeof(struct t10_pi_tuple), .tag_size = 0, }; EXPORT_SYMBOL(t10_pi_type1_ip); struct blk_integrity t10_pi_type3_crc = { .name = "T10-DIF-TYPE3-CRC", .generate_fn = t10_pi_type3_generate_crc, .verify_fn = t10_pi_type3_verify_crc, .tuple_size = sizeof(struct t10_pi_tuple), .tag_size = 0, }; EXPORT_SYMBOL(t10_pi_type3_crc); struct blk_integrity t10_pi_type3_ip = { .name = "T10-DIF-TYPE3-IP", .generate_fn = t10_pi_type3_generate_ip, .verify_fn = t10_pi_type3_verify_ip, .tuple_size = sizeof(struct t10_pi_tuple), .tag_size = 0, }; EXPORT_SYMBOL(t10_pi_type3_ip);