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