xref: /freebsd/sys/cddl/boot/zfs/skein_zfs.c (revision 783d3ff6d7fae619db8a7990b8a6387de0c677b5)
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  */
24 #include <skein.h>
25 
26 /*
27  * Computes a native 256-bit skein MAC checksum. Please note that this
28  * function requires the presence of a ctx_template that should be allocated
29  * using zio_checksum_skein_tmpl_init.
30  */
31 /*ARGSUSED*/
32 static void
33 zio_checksum_skein_native(const void *buf, uint64_t size,
34     const void *ctx_template, zio_cksum_t *zcp)
35 {
36 	Skein_512_Ctxt_t	ctx;
37 
38 	ASSERT(ctx_template != NULL);
39 	bcopy(ctx_template, &ctx, sizeof (ctx));
40 	(void) Skein_512_Update(&ctx, buf, size);
41 	(void) Skein_512_Final(&ctx, (uint8_t *)zcp);
42 	bzero(&ctx, sizeof (ctx));
43 }
44 
45 /*
46  * Byteswapped version of zio_checksum_skein_native. This just invokes
47  * the native checksum function and byteswaps the resulting checksum (since
48  * skein is internally endian-insensitive).
49  */
50 static void
51 zio_checksum_skein_byteswap(const void *buf, uint64_t size,
52     const void *ctx_template, zio_cksum_t *zcp)
53 {
54 	zio_cksum_t	tmp;
55 
56 	zio_checksum_skein_native(buf, size, ctx_template, &tmp);
57 	zcp->zc_word[0] = BSWAP_64(tmp.zc_word[0]);
58 	zcp->zc_word[1] = BSWAP_64(tmp.zc_word[1]);
59 	zcp->zc_word[2] = BSWAP_64(tmp.zc_word[2]);
60 	zcp->zc_word[3] = BSWAP_64(tmp.zc_word[3]);
61 }
62 
63 /*
64  * Allocates a skein MAC template suitable for using in skein MAC checksum
65  * computations and returns a pointer to it.
66  */
67 static void *
68 zio_checksum_skein_tmpl_init(const zio_cksum_salt_t *salt)
69 {
70 	Skein_512_Ctxt_t	*ctx;
71 
72 	ctx = malloc(sizeof (*ctx));
73 	bzero(ctx, sizeof (*ctx));
74 	(void) Skein_512_InitExt(ctx, sizeof (zio_cksum_t) * 8, 0,
75 	    salt->zcs_bytes, sizeof (salt->zcs_bytes));
76 	return (ctx);
77 }
78 
79 /*
80  * Frees a skein context template previously allocated using
81  * zio_checksum_skein_tmpl_init.
82  */
83 static void
84 zio_checksum_skein_tmpl_free(void *ctx_template)
85 {
86 	Skein_512_Ctxt_t	*ctx = ctx_template;
87 
88 	bzero(ctx, sizeof (*ctx));
89 	free(ctx);
90 }
91