1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://opensource.org/licenses/CDDL-1.0.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright 2013 Saso Kiselkov.  All rights reserved.
23 * Copyright (c) 2016 by Delphix. All rights reserved.
24 */
25#include <sys/zfs_context.h>
26#include <sys/zio.h>
27#ifdef _KERNEL
28#include <crypto/skein/skein.h>
29#else
30#include <skein.h>
31#endif
32#include <sys/abd.h>
33
34static int
35skein_incremental(void *buf, size_t size, void *arg)
36{
37	Skein_512_Ctxt_t *ctx = arg;
38	(void) Skein_512_Update(ctx, buf, size);
39	return (0);
40}
41
42/*
43 * Computes a native 256-bit skein MAC checksum. Please note that this
44 * function requires the presence of a ctx_template that should be allocated
45 * using abd_checksum_skein_tmpl_init.
46 */
47/*ARGSUSED*/
48void
49abd_checksum_skein_native(abd_t *abd, uint64_t size,
50    const void *ctx_template, zio_cksum_t *zcp)
51{
52	Skein_512_Ctxt_t	ctx;
53
54	ASSERT(ctx_template != NULL);
55	bcopy(ctx_template, &ctx, sizeof (ctx));
56	(void) abd_iterate_func(abd, 0, size, skein_incremental, &ctx);
57	(void) Skein_512_Final(&ctx, (uint8_t *)zcp);
58	bzero(&ctx, sizeof (ctx));
59}
60
61/*
62 * Byteswapped version of abd_checksum_skein_native. This just invokes
63 * the native checksum function and byteswaps the resulting checksum (since
64 * skein is internally endian-insensitive).
65 */
66void
67abd_checksum_skein_byteswap(abd_t *abd, uint64_t size,
68    const void *ctx_template, zio_cksum_t *zcp)
69{
70	zio_cksum_t	tmp;
71
72	abd_checksum_skein_native(abd, size, ctx_template, &tmp);
73	zcp->zc_word[0] = BSWAP_64(tmp.zc_word[0]);
74	zcp->zc_word[1] = BSWAP_64(tmp.zc_word[1]);
75	zcp->zc_word[2] = BSWAP_64(tmp.zc_word[2]);
76	zcp->zc_word[3] = BSWAP_64(tmp.zc_word[3]);
77}
78
79/*
80 * Allocates a skein MAC template suitable for using in skein MAC checksum
81 * computations and returns a pointer to it.
82 */
83void *
84abd_checksum_skein_tmpl_init(const zio_cksum_salt_t *salt)
85{
86	Skein_512_Ctxt_t	*ctx;
87
88	ctx = kmem_zalloc(sizeof (*ctx), KM_SLEEP);
89	(void) Skein_512_InitExt(ctx, sizeof (zio_cksum_t) * 8, 0,
90	    salt->zcs_bytes, sizeof (salt->zcs_bytes));
91	return (ctx);
92}
93
94/*
95 * Frees a skein context template previously allocated using
96 * abd_checksum_skein_tmpl_init.
97 */
98void
99abd_checksum_skein_tmpl_free(void *ctx_template)
100{
101	Skein_512_Ctxt_t	*ctx = ctx_template;
102
103	bzero(ctx, sizeof (*ctx));
104	kmem_free(ctx, sizeof (*ctx));
105}
106