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 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 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 */ 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