diff options
Diffstat (limited to 'siphash.h')
| -rw-r--r-- | siphash.h | 113 |
1 files changed, 111 insertions, 2 deletions
@@ -1,11 +1,120 @@ /* SPDX-License-Identifier: GPL-2.0-or-later - * Copyright (c) 2021 Red Hat GmbH + * Copyright Red Hat * Author: Stefano Brivio <sbrivio@redhat.com> - */ + * Author: David Gibson <david@gibson.dropbear.id.au> + * + * This is an implementation of the SipHash-2-4-64 functions needed for TCP + * initial sequence numbers and socket lookup table hash for IPv4 and IPv6, see: + * + * Aumasson, J.P. and Bernstein, D.J., 2012, December. SipHash: a fast + * short-input PRF. In International Conference on Cryptology in India + * (pp. 489-508). Springer, Berlin, Heidelberg. + * + * http://cr.yp.to/siphash/siphash-20120918.pdf + * + * This includes code from the reference SipHash implementation at + * https://github.com/veorq/SipHash/ originally licensed as follows: + * + * -- + * SipHash reference C implementation + * + * Copyright (c) 2012-2021 Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com> + * Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to> + * + * To the extent possible under law, the author(s) have dedicated all copyright + * and related and neighboring rights to this software to the public domain + * worldwide. This software is distributed without any warranty. + * + * You should have received a copy of the CC0 Public Domain Dedication along + * with this software. If not, see + * <http://creativecommons.org/publicdomain/zero/1.0/>. + * -- + * + * and from the Linux kernel implementation (lib/siphash.c), originally licensed + * as follows: + * + * -- + * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + * + * This file is provided under a dual BSD/GPLv2 license. + * -- + * +*/ #ifndef SIPHASH_H #define SIPHASH_H +/** + * struct siphash_state - Internal state of siphash calculation + */ +struct siphash_state { + uint64_t v[4]; +}; + +#define SIPHASH_INIT(k) { { \ + 0x736f6d6570736575ULL ^ (k)[0], \ + 0x646f72616e646f6dULL ^ (k)[1], \ + 0x6c7967656e657261ULL ^ (k)[0], \ + 0x7465646279746573ULL ^ (k)[1] \ + } } + +/** + * sipround() - Perform rounds of SipHash scrambling + * @v: siphash state (4 x 64-bit integers) + * @n: Number of rounds to apply + */ +static inline void sipround(struct siphash_state *state, int n) +{ + int i; + +#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b)))) + + for (i = 0; i < n; i++) { + + state->v[0] += state->v[1]; + state->v[1] = ROTL(state->v[1], 13) ^ state->v[0]; + state->v[0] = ROTL(state->v[0], 32); + state->v[2] += state->v[3]; + state->v[3] = ROTL(state->v[3], 16) ^ state->v[2]; + state->v[0] += state->v[3]; + state->v[3] = ROTL(state->v[3], 21) ^ state->v[0]; + state->v[2] += state->v[1]; + state->v[1] = ROTL(state->v[1], 17) ^ state->v[2]; + state->v[2] = ROTL(state->v[2], 32); + } + +#undef ROTL +} + +/** + * siphash_feed() - Fold 64-bits of data into the hash state + * @v: siphash state (4 x 64-bit integers) + * @in: New value to fold into hash + */ +static inline void siphash_feed(struct siphash_state *state, uint64_t in) +{ + state->v[3] ^= in; + sipround(state, 2); + state->v[0] ^= in; +} + +/** + * siphash_final - Finalize SipHash calculations + * @v: siphash state (4 x 64-bit integers) + * @len: Total length of input data + * @tail: Final data for the hash (<= 7 bytes) + */ +static inline uint64_t siphash_final(struct siphash_state *state, + size_t len, uint64_t tail) +{ + uint64_t b = (uint64_t)(len) << 56 | tail; + + siphash_feed(state, b); + state->v[2] ^= 0xff; + sipround(state, 4); + return state->v[0] ^ state->v[1] ^ state->v[2] ^ state->v[3]; +} + uint64_t siphash_8b(const uint8_t *in, const uint64_t *k); uint64_t siphash_12b(const uint8_t *in, const uint64_t *k); uint64_t siphash_20b(const uint8_t *in, const uint64_t *k); |