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Diffstat (limited to 'fs/bcachefs/siphash.c')
| -rw-r--r-- | fs/bcachefs/siphash.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/fs/bcachefs/siphash.c b/fs/bcachefs/siphash.c new file mode 100644 index 0000000000..dc1a27cc31 --- /dev/null +++ b/fs/bcachefs/siphash.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: BSD-3-Clause +/* $OpenBSD: siphash.c,v 1.3 2015/02/20 11:51:03 tedu Exp $ */ + +/*- + * Copyright (c) 2013 Andre Oppermann <andre@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* + * SipHash is a family of PRFs SipHash-c-d where the integer parameters c and d + * are the number of compression rounds and the number of finalization rounds. + * A compression round is identical to a finalization round and this round + * function is called SipRound. Given a 128-bit key k and a (possibly empty) + * byte string m, SipHash-c-d returns a 64-bit value SipHash-c-d(k; m). + * + * Implemented from the paper "SipHash: a fast short-input PRF", 2012.09.18, + * by Jean-Philippe Aumasson and Daniel J. Bernstein, + * Permanent Document ID b9a943a805fbfc6fde808af9fc0ecdfa + * https://131002.net/siphash/siphash.pdf + * https://131002.net/siphash/ + */ + +#include <asm/byteorder.h> +#include <asm/unaligned.h> +#include <linux/bitops.h> +#include <linux/string.h> + +#include "siphash.h" + +static void SipHash_Rounds(SIPHASH_CTX *ctx, int rounds) +{ + while (rounds--) { + ctx->v[0] += ctx->v[1]; + ctx->v[2] += ctx->v[3]; + ctx->v[1] = rol64(ctx->v[1], 13); + ctx->v[3] = rol64(ctx->v[3], 16); + + ctx->v[1] ^= ctx->v[0]; + ctx->v[3] ^= ctx->v[2]; + ctx->v[0] = rol64(ctx->v[0], 32); + + ctx->v[2] += ctx->v[1]; + ctx->v[0] += ctx->v[3]; + ctx->v[1] = rol64(ctx->v[1], 17); + ctx->v[3] = rol64(ctx->v[3], 21); + + ctx->v[1] ^= ctx->v[2]; + ctx->v[3] ^= ctx->v[0]; + ctx->v[2] = rol64(ctx->v[2], 32); + } +} + +static void SipHash_CRounds(SIPHASH_CTX *ctx, const void *ptr, int rounds) +{ + u64 m = get_unaligned_le64(ptr); + + ctx->v[3] ^= m; + SipHash_Rounds(ctx, rounds); + ctx->v[0] ^= m; +} + +void SipHash_Init(SIPHASH_CTX *ctx, const SIPHASH_KEY *key) +{ + u64 k0, k1; + + k0 = le64_to_cpu(key->k0); + k1 = le64_to_cpu(key->k1); + + ctx->v[0] = 0x736f6d6570736575ULL ^ k0; + ctx->v[1] = 0x646f72616e646f6dULL ^ k1; + ctx->v[2] = 0x6c7967656e657261ULL ^ k0; + ctx->v[3] = 0x7465646279746573ULL ^ k1; + + memset(ctx->buf, 0, sizeof(ctx->buf)); + ctx->bytes = 0; +} + +void SipHash_Update(SIPHASH_CTX *ctx, int rc, int rf, + const void *src, size_t len) +{ + const u8 *ptr = src; + size_t left, used; + + if (len == 0) + return; + + used = ctx->bytes % sizeof(ctx->buf); + ctx->bytes += len; + + if (used > 0) { + left = sizeof(ctx->buf) - used; + + if (len >= left) { + memcpy(&ctx->buf[used], ptr, left); + SipHash_CRounds(ctx, ctx->buf, rc); + len -= left; + ptr += left; + } else { + memcpy(&ctx->buf[used], ptr, len); + return; + } + } + + while (len >= sizeof(ctx->buf)) { + SipHash_CRounds(ctx, ptr, rc); + len -= sizeof(ctx->buf); + ptr += sizeof(ctx->buf); + } + + if (len > 0) + memcpy(&ctx->buf[used], ptr, len); +} + +void SipHash_Final(void *dst, SIPHASH_CTX *ctx, int rc, int rf) +{ + u64 r; + + r = SipHash_End(ctx, rc, rf); + + *((__le64 *) dst) = cpu_to_le64(r); +} + +u64 SipHash_End(SIPHASH_CTX *ctx, int rc, int rf) +{ + u64 r; + size_t left, used; + + used = ctx->bytes % sizeof(ctx->buf); + left = sizeof(ctx->buf) - used; + memset(&ctx->buf[used], 0, left - 1); + ctx->buf[7] = ctx->bytes; + + SipHash_CRounds(ctx, ctx->buf, rc); + ctx->v[2] ^= 0xff; + SipHash_Rounds(ctx, rf); + + r = (ctx->v[0] ^ ctx->v[1]) ^ (ctx->v[2] ^ ctx->v[3]); + memset(ctx, 0, sizeof(*ctx)); + return r; +} + +u64 SipHash(const SIPHASH_KEY *key, int rc, int rf, const void *src, size_t len) +{ + SIPHASH_CTX ctx; + + SipHash_Init(&ctx, key); + SipHash_Update(&ctx, rc, rf, src, len); + return SipHash_End(&ctx, rc, rf); +} |