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 */ 56 struct 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 */ 66 struct 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 */ 78 struct 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 87 static inline struct gf128 88 gf128_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 } 99 100 static inline void 101 gf128_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 } 110 111 static inline struct gf128 __pure /* XXX - __pure2 instead */ 112 gf128_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 } 119 120 void gf128_genmultable(struct gf128 h, struct gf128table *t); 121 void gf128_genmultable4(struct gf128 h, struct gf128table4 *t); 122 struct gf128 gf128_mul(struct gf128 v, struct gf128table *tbl); 123 struct gf128 gf128_mul4(struct gf128 a, struct gf128 b, struct gf128 c, 124 struct gf128 d, struct gf128table4 *tbl); 125 struct gf128 gf128_mul4b(struct gf128 r, const uint8_t *v, 126 struct gf128table4 *tbl); 127 128 #endif /* _GFMULT_H_ */ 129