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04b10a8d90
A number of checksum and hash functions require workarounds for the odd behaviour of Type-Baased Alias Analysis. We have a detailed comment about this on siphash_8b() and other functions reference that. Move the main comment to csume_16b() instead, because we're going to reorganise things in siphash.c. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* PASST - Plug A Simple Socket Transport
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* for qemu/UNIX domain socket mode
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*
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* PASTA - Pack A Subtle Tap Abstraction
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* for network namespace/tap device mode
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*
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* siphash.c - SipHash routines
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*
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* Copyright (c) 2020-2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#include <stddef.h>
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#include <stdint.h>
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#include "siphash.h"
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/**
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* siphash_8b() - Table index or timestamp offset for TCP over IPv4 (8 bytes in)
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* @in: Input data (remote address and two ports, or two addresses)
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* @k: Hash function key, 128 bits
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*
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* Return: the 64-bit hash output
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*/
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/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
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__attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
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/* cppcheck-suppress unusedFunction */
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uint64_t siphash_8b(const uint8_t *in, const uint64_t *k)
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{
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struct siphash_state state = SIPHASH_INIT(k);
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siphash_feed(&state, *(uint64_t *)in);
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return siphash_final(&state, 8, 0);
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}
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/**
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* siphash_12b() - Initial sequence number for TCP over IPv4 (12 bytes in)
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* @in: Input data (two addresses, two ports)
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* @k: Hash function key, 128 bits
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*
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* Return: the 64-bit hash output
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*/
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/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
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__attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
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/* cppcheck-suppress unusedFunction */
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uint64_t siphash_12b(const uint8_t *in, const uint64_t *k)
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{
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struct siphash_state state = SIPHASH_INIT(k);
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uint32_t *in32 = (uint32_t *)in;
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siphash_feed(&state, (uint64_t)(*(in32 + 1)) << 32 | *in32);
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return siphash_final(&state, 12, *(in32 + 2));
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}
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/**
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* siphash_20b() - Table index for TCP over IPv6 (20 bytes in)
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* @in: Input data (remote address, two ports)
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* @k: Hash function key, 128 bits
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*
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* Return: the 64-bit hash output
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*/
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/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
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__attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
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uint64_t siphash_20b(const uint8_t *in, const uint64_t *k)
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{
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struct siphash_state state = SIPHASH_INIT(k);
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uint32_t *in32 = (uint32_t *)in;
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int i;
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for (i = 0; i < 2; i++, in32 += 2)
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siphash_feed(&state, (uint64_t)(*(in32 + 1)) << 32 | *in32);
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return siphash_final(&state, 20, *in32);
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}
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/**
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* siphash_32b() - Timestamp offset for TCP over IPv6 (32 bytes in)
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* @in: Input data (two addresses)
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* @k: Hash function key, 128 bits
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*
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* Return: the 64-bit hash output
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*/
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/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
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__attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
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/* cppcheck-suppress unusedFunction */
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uint64_t siphash_32b(const uint8_t *in, const uint64_t *k)
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{
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struct siphash_state state = SIPHASH_INIT(k);
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uint64_t *in64 = (uint64_t *)in;
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int i;
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for (i = 0; i < 4; i++, in64++)
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siphash_feed(&state, *in64);
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return siphash_final(&state, 32, 0);
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}
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/**
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* siphash_36b() - Initial sequence number for TCP over IPv6 (36 bytes in)
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* @in: Input data (two addresses, two ports)
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* @k: Hash function key, 128 bits
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*
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* Return: the 64-bit hash output
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*/
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/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
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__attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
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uint64_t siphash_36b(const uint8_t *in, const uint64_t *k)
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{
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struct siphash_state state = SIPHASH_INIT(k);
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uint32_t *in32 = (uint32_t *)in;
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int i;
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for (i = 0; i < 4; i++, in32 += 2)
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siphash_feed(&state, (uint64_t)(*(in32 + 1)) << 32 | *in32);
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return siphash_final(&state, 36, *in32);
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}
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