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 */
53 struct 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 */
63 struct 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 */
75 struct 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
84 static inline struct gf128
gf128_read(const uint8_t * buf)85 gf128_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
97 static inline void
gf128_write(struct gf128 v,uint8_t * buf)98 gf128_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
108 static inline struct gf128 __pure /* XXX - __pure2 instead */
gf128_add(struct gf128 a,struct gf128 b)109 gf128_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
117 void gf128_genmultable(struct gf128 h, struct gf128table *t);
118 void gf128_genmultable4(struct gf128 h, struct gf128table4 *t);
119 struct gf128 gf128_mul(struct gf128 v, struct gf128table *tbl);
120 struct gf128 gf128_mul4(struct gf128 a, struct gf128 b, struct gf128 c,
121 struct gf128 d, struct gf128table4 *tbl);
122 struct gf128 gf128_mul4b(struct gf128 r, const uint8_t *v,
123 struct gf128table4 *tbl);
124
125 #endif /* _GFMULT_H_ */
126