linux/lib/siphash.c

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
/* Copyright (C) 2016-2022 Jason A. Donenfeld <[email protected]>. All Rights Reserved.
 *
 * SipHash: a fast short-input PRF
 * https://131002.net/siphash/
 *
 * This implementation is specifically for SipHash2-4 for a secure PRF
 * and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for
 * hashtables.
 */

#include <linux/siphash.h>
#include <asm/unaligned.h>

#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
#include <linux/dcache.h>
#include <asm/word-at-a-time.h>
#endif

#define SIPROUND …

#define PREAMBLE(len) …

#define POSTAMBLE …

#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key)
{
	const u8 *end = data + len - (len % sizeof(u64));
	const u8 left = len & (sizeof(u64) - 1);
	u64 m;
	PREAMBLE(len)
	for (; data != end; data += sizeof(u64)) {
		m = le64_to_cpup(data);
		v3 ^= m;
		SIPROUND;
		SIPROUND;
		v0 ^= m;
	}
#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
	if (left)
		b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) &
						  bytemask_from_count(left)));
#else
	switch (left) {
	case 7: b |= ((u64)end[6]) << 48; fallthrough;
	case 6: b |= ((u64)end[5]) << 40; fallthrough;
	case 5: b |= ((u64)end[4]) << 32; fallthrough;
	case 4: b |= le32_to_cpup(data); break;
	case 3: b |= ((u64)end[2]) << 16; fallthrough;
	case 2: b |= le16_to_cpup(data); break;
	case 1: b |= end[0];
	}
#endif
	POSTAMBLE
}
EXPORT_SYMBOL(__siphash_aligned);
#endif

u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

/**
 * siphash_1u64 - compute 64-bit siphash PRF value of a u64
 * @first: first u64
 * @key: the siphash key
 */
u64 siphash_1u64(const u64 first, const siphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

/**
 * siphash_2u64 - compute 64-bit siphash PRF value of 2 u64
 * @first: first u64
 * @second: second u64
 * @key: the siphash key
 */
u64 siphash_2u64(const u64 first, const u64 second, const siphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

/**
 * siphash_3u64 - compute 64-bit siphash PRF value of 3 u64
 * @first: first u64
 * @second: second u64
 * @third: third u64
 * @key: the siphash key
 */
u64 siphash_3u64(const u64 first, const u64 second, const u64 third,
		 const siphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

/**
 * siphash_4u64 - compute 64-bit siphash PRF value of 4 u64
 * @first: first u64
 * @second: second u64
 * @third: third u64
 * @forth: forth u64
 * @key: the siphash key
 */
u64 siphash_4u64(const u64 first, const u64 second, const u64 third,
		 const u64 forth, const siphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

u64 siphash_1u32(const u32 first, const siphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

u64 siphash_3u32(const u32 first, const u32 second, const u32 third,
		 const siphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

#if BITS_PER_LONG == 64
/* Note that on 64-bit, we make HalfSipHash1-3 actually be SipHash1-3, for
 * performance reasons. On 32-bit, below, we actually implement HalfSipHash1-3.
 */

#define HSIPROUND …
#define HPREAMBLE(len) …
#define HPOSTAMBLE …

#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
u32 __hsiphash_aligned(const void *data, size_t len, const hsiphash_key_t *key)
{
	const u8 *end = data + len - (len % sizeof(u64));
	const u8 left = len & (sizeof(u64) - 1);
	u64 m;
	HPREAMBLE(len)
	for (; data != end; data += sizeof(u64)) {
		m = le64_to_cpup(data);
		v3 ^= m;
		HSIPROUND;
		v0 ^= m;
	}
#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
	if (left)
		b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) &
						  bytemask_from_count(left)));
#else
	switch (left) {
	case 7: b |= ((u64)end[6]) << 48; fallthrough;
	case 6: b |= ((u64)end[5]) << 40; fallthrough;
	case 5: b |= ((u64)end[4]) << 32; fallthrough;
	case 4: b |= le32_to_cpup(data); break;
	case 3: b |= ((u64)end[2]) << 16; fallthrough;
	case 2: b |= le16_to_cpup(data); break;
	case 1: b |= end[0];
	}
#endif
	HPOSTAMBLE
}
EXPORT_SYMBOL(__hsiphash_aligned);
#endif

u32 __hsiphash_unaligned(const void *data, size_t len,
			 const hsiphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

/**
 * hsiphash_1u32 - compute 64-bit hsiphash PRF value of a u32
 * @first: first u32
 * @key: the hsiphash key
 */
u32 hsiphash_1u32(const u32 first, const hsiphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

/**
 * hsiphash_2u32 - compute 32-bit hsiphash PRF value of 2 u32
 * @first: first u32
 * @second: second u32
 * @key: the hsiphash key
 */
u32 hsiphash_2u32(const u32 first, const u32 second, const hsiphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

/**
 * hsiphash_3u32 - compute 32-bit hsiphash PRF value of 3 u32
 * @first: first u32
 * @second: second u32
 * @third: third u32
 * @key: the hsiphash key
 */
u32 hsiphash_3u32(const u32 first, const u32 second, const u32 third,
		  const hsiphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);

/**
 * hsiphash_4u32 - compute 32-bit hsiphash PRF value of 4 u32
 * @first: first u32
 * @second: second u32
 * @third: third u32
 * @forth: forth u32
 * @key: the hsiphash key
 */
u32 hsiphash_4u32(const u32 first, const u32 second, const u32 third,
		  const u32 forth, const hsiphash_key_t *key)
{ … }
EXPORT_SYMBOL(…);
#else
#define HSIPROUND …

#define HPREAMBLE …

#define HPOSTAMBLE …

#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
u32 __hsiphash_aligned(const void *data, size_t len, const hsiphash_key_t *key)
{
	const u8 *end = data + len - (len % sizeof(u32));
	const u8 left = len & (sizeof(u32) - 1);
	u32 m;
	HPREAMBLE(len)
	for (; data != end; data += sizeof(u32)) {
		m = le32_to_cpup(data);
		v3 ^= m;
		HSIPROUND;
		v0 ^= m;
	}
	switch (left) {
	case 3: b |= ((u32)end[2]) << 16; fallthrough;
	case 2: b |= le16_to_cpup(data); break;
	case 1: b |= end[0];
	}
	HPOSTAMBLE
}
EXPORT_SYMBOL(__hsiphash_aligned);
#endif

u32 __hsiphash_unaligned(const void *data, size_t len,
			 const hsiphash_key_t *key)
{
	const u8 *end = data + len - (len % sizeof(u32));
	const u8 left = len & (sizeof(u32) - 1);
	u32 m;
	HPREAMBLE(len)
	for (; data != end; data += sizeof(u32)) {
		m = get_unaligned_le32(data);
		v3 ^= m;
		HSIPROUND;
		v0 ^= m;
	}
	switch (left) {
	case 3: b |= ((u32)end[2]) << 16; fallthrough;
	case 2: b |= get_unaligned_le16(end); break;
	case 1: b |= end[0];
	}
	HPOSTAMBLE
}
EXPORT_SYMBOL(__hsiphash_unaligned);

/**
 * hsiphash_1u32 - compute 32-bit hsiphash PRF value of a u32
 * @first: first u32
 * @key: the hsiphash key
 */
u32 hsiphash_1u32(const u32 first, const hsiphash_key_t *key)
{
	HPREAMBLE(4)
	v3 ^= first;
	HSIPROUND;
	v0 ^= first;
	HPOSTAMBLE
}
EXPORT_SYMBOL(hsiphash_1u32);

/**
 * hsiphash_2u32 - compute 32-bit hsiphash PRF value of 2 u32
 * @first: first u32
 * @second: second u32
 * @key: the hsiphash key
 */
u32 hsiphash_2u32(const u32 first, const u32 second, const hsiphash_key_t *key)
{
	HPREAMBLE(8)
	v3 ^= first;
	HSIPROUND;
	v0 ^= first;
	v3 ^= second;
	HSIPROUND;
	v0 ^= second;
	HPOSTAMBLE
}
EXPORT_SYMBOL(hsiphash_2u32);

/**
 * hsiphash_3u32 - compute 32-bit hsiphash PRF value of 3 u32
 * @first: first u32
 * @second: second u32
 * @third: third u32
 * @key: the hsiphash key
 */
u32 hsiphash_3u32(const u32 first, const u32 second, const u32 third,
		  const hsiphash_key_t *key)
{
	HPREAMBLE(12)
	v3 ^= first;
	HSIPROUND;
	v0 ^= first;
	v3 ^= second;
	HSIPROUND;
	v0 ^= second;
	v3 ^= third;
	HSIPROUND;
	v0 ^= third;
	HPOSTAMBLE
}
EXPORT_SYMBOL(hsiphash_3u32);

/**
 * hsiphash_4u32 - compute 32-bit hsiphash PRF value of 4 u32
 * @first: first u32
 * @second: second u32
 * @third: third u32
 * @forth: forth u32
 * @key: the hsiphash key
 */
u32 hsiphash_4u32(const u32 first, const u32 second, const u32 third,
		  const u32 forth, const hsiphash_key_t *key)
{
	HPREAMBLE(16)
	v3 ^= first;
	HSIPROUND;
	v0 ^= first;
	v3 ^= second;
	HSIPROUND;
	v0 ^= second;
	v3 ^= third;
	HSIPROUND;
	v0 ^= third;
	v3 ^= forth;
	HSIPROUND;
	v0 ^= forth;
	HPOSTAMBLE
}
EXPORT_SYMBOL(hsiphash_4u32);
#endif