1/*-
2 * Copyright (c) 2014 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by John-Mark Gurney under
6 * the sponsorship of the FreeBSD Foundation and
7 * Rubicon Communications, LLC (Netgate).
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1.  Redistributions of source code must retain the above copyright
12 *     notice, this list of conditions and the following disclaimer.
13 * 2.  Redistributions in binary form must reproduce the above copyright
14 *     notice, this list of conditions and the following disclaimer in the
15 *     documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	$FreeBSD$
30 *
31 */
32
33#ifndef _GFMULT_H_
34#define _GFMULT_H_
35
36#ifdef __APPLE__
37#define	__aligned(x)    __attribute__((__aligned__(x)))
38#define	be64dec(buf)	__builtin_bswap64(*(uint64_t *)buf)
39#define	be64enc(buf, x)	(*(uint64_t *)buf = __builtin_bswap64(x))
40#else
41#include <sys/endian.h>
42#endif
43
44#ifdef _KERNEL
45#include <sys/types.h>
46#else
47#include <stdint.h>
48#include <strings.h>
49#endif
50
51#define REQ_ALIGN	(16 * 4)
52/*
53 * The rows are striped across cache lines.  Note that the indexes
54 * are bit reversed to make accesses quicker.
55 */
56struct gf128table {
57	uint32_t a[16] __aligned(REQ_ALIGN);	/* bits   0 - 31 */
58	uint32_t b[16] __aligned(REQ_ALIGN);	/* bits  63 - 32 */
59	uint32_t c[16] __aligned(REQ_ALIGN);	/* bits  95 - 64 */
60	uint32_t d[16] __aligned(REQ_ALIGN);	/* bits 127 - 96 */
61} __aligned(REQ_ALIGN);
62
63/*
64 * A set of tables that contain h, h^2, h^3, h^4.  To be used w/ gf128_mul4.
65 */
66struct gf128table4 {
67	struct gf128table	tbls[4];
68};
69
70/*
71 * GCM per spec is bit reversed in memory.  So byte 0 is really bit reversed
72 * and contains bits 0-7.  We can deal w/ this by using right shifts and
73 * related math instead of having to bit reverse everything.  This means that
74 * the low bits are in v[0] (bits 0-63) and reverse order, while the high
75 * bits are in v[1] (bits 64-127) and reverse order.  The high bit of v[0] is
76 * bit 0, and the low bit of v[1] is bit 127.
77 */
78struct gf128 {
79	uint64_t v[2];
80};
81
82/* Note that we don't bit reverse in MAKE_GF128. */
83#define MAKE_GF128(a, b)	((struct gf128){.v = { (a), (b) } })
84#define GF128_EQ(a, b)		((((a).v[0] ^ (b).v[0]) | \
85				    ((a).v[1] ^ (b).v[1])) == 0)
86
87static inline struct gf128
88gf128_read(const uint8_t *buf)
89{
90	struct gf128 r;
91
92	r.v[0] = be64dec(buf);
93	buf += sizeof(uint64_t);
94
95	r.v[1] = be64dec(buf);
96
97	return r;
98}
99
100static inline void
101gf128_write(struct gf128 v, uint8_t *buf)
102{
103	uint64_t tmp;
104
105	be64enc(buf, v.v[0]);
106	buf += sizeof tmp;
107
108	be64enc(buf, v.v[1]);
109}
110
111static inline struct gf128 __pure /* XXX - __pure2 instead */
112gf128_add(struct gf128 a, struct gf128 b)
113{
114	a.v[0] ^= b.v[0];
115	a.v[1] ^= b.v[1];
116
117	return a;
118}
119
120void gf128_genmultable(struct gf128 h, struct gf128table *t);
121void gf128_genmultable4(struct gf128 h, struct gf128table4 *t);
122struct gf128 gf128_mul(struct gf128 v, struct gf128table *tbl);
123struct gf128 gf128_mul4(struct gf128 a, struct gf128 b, struct gf128 c,
124    struct gf128 d, struct gf128table4 *tbl);
125struct gf128 gf128_mul4b(struct gf128 r, const uint8_t *v,
126    struct gf128table4 *tbl);
127
128#endif /* _GFMULT_H_ */
129