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/*
SipHash reference C implementation
Written in 2012 by
Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
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/>.
(Minimal changes made by Lennart Poettering, to make clean for inclusion in systemd)
(Refactored by Tom Gundersen to split up in several functions and follow systemd
coding style)
*/
#include "siphash24.h"
#include "macro.h"
#include "unaligned.h"
static inline uint64_t rotate_left(uint64_t x, uint8_t b) {
assert(b < 64);
return (x << b) | (x >> (64 - b));
}
static inline void sipround(struct siphash *state) {
assert(state);
state->v0 += state->v1;
state->v1 = rotate_left(state->v1, 13);
state->v1 ^= state->v0;
state->v0 = rotate_left(state->v0, 32);
state->v2 += state->v3;
state->v3 = rotate_left(state->v3, 16);
state->v3 ^= state->v2;
state->v0 += state->v3;
state->v3 = rotate_left(state->v3, 21);
state->v3 ^= state->v0;
state->v2 += state->v1;
state->v1 = rotate_left(state->v1, 17);
state->v1 ^= state->v2;
state->v2 = rotate_left(state->v2, 32);
}
void siphash24_init(struct siphash *state, const uint8_t k[16]) {
uint64_t k0, k1;
assert(state);
assert(k);
k0 = unaligned_read_le64(k);
k1 = unaligned_read_le64(k + 8);
*state = (struct siphash) {
/* "somepseudorandomlygeneratedbytes" */
.v0 = 0x736f6d6570736575ULL ^ k0,
.v1 = 0x646f72616e646f6dULL ^ k1,
.v2 = 0x6c7967656e657261ULL ^ k0,
.v3 = 0x7465646279746573ULL ^ k1,
.padding = 0,
.inlen = 0,
};
}
void siphash24_compress(const void *_in, size_t inlen, struct siphash *state) {
const uint8_t *in = _in;
const uint8_t *end = in + inlen;
size_t left = state->inlen & 7;
uint64_t m;
assert(in);
assert(state);
/* Update total length */
state->inlen += inlen;
/* If padding exists, fill it out */
if (left > 0) {
for ( ; in < end && left < 8; in ++, left ++)
state->padding |= ((uint64_t) *in) << (left * 8);
if (in == end && left < 8)
/* We did not have enough input to fill out the padding completely */
return;
#ifdef DEBUG
printf("(%3zu) v0 %08x %08x\n", state->inlen, (uint32_t) (state->v0 >> 32), (uint32_t) state->v0);
printf("(%3zu) v1 %08x %08x\n", state->inlen, (uint32_t) (state->v1 >> 32), (uint32_t) state->v1);
printf("(%3zu) v2 %08x %08x\n", state->inlen, (uint32_t) (state->v2 >> 32), (uint32_t) state->v2);
printf("(%3zu) v3 %08x %08x\n", state->inlen, (uint32_t) (state->v3 >> 32), (uint32_t) state->v3);
printf("(%3zu) compress padding %08x %08x\n", state->inlen, (uint32_t) (state->padding >> 32), (uint32_t)state->padding);
#endif
state->v3 ^= state->padding;
sipround(state);
sipround(state);
state->v0 ^= state->padding;
state->padding = 0;
}
end -= (state->inlen % sizeof(uint64_t));
for ( ; in < end; in += 8) {
m = unaligned_read_le64(in);
#ifdef DEBUG
printf("(%3zu) v0 %08x %08x\n", state->inlen, (uint32_t) (state->v0 >> 32), (uint32_t) state->v0);
printf("(%3zu) v1 %08x %08x\n", state->inlen, (uint32_t) (state->v1 >> 32), (uint32_t) state->v1);
printf("(%3zu) v2 %08x %08x\n", state->inlen, (uint32_t) (state->v2 >> 32), (uint32_t) state->v2);
printf("(%3zu) v3 %08x %08x\n", state->inlen, (uint32_t) (state->v3 >> 32), (uint32_t) state->v3);
printf("(%3zu) compress %08x %08x\n", state->inlen, (uint32_t) (m >> 32), (uint32_t) m);
#endif
state->v3 ^= m;
sipround(state);
sipround(state);
state->v0 ^= m;
}
left = state->inlen & 7;
switch (left) {
case 7:
state->padding |= ((uint64_t) in[6]) << 48;
case 6:
state->padding |= ((uint64_t) in[5]) << 40;
case 5:
state->padding |= ((uint64_t) in[4]) << 32;
case 4:
state->padding |= ((uint64_t) in[3]) << 24;
case 3:
state->padding |= ((uint64_t) in[2]) << 16;
case 2:
state->padding |= ((uint64_t) in[1]) << 8;
case 1:
state->padding |= ((uint64_t) in[0]);
case 0:
break;
}
}
uint64_t siphash24_finalize(struct siphash *state) {
uint64_t b;
assert(state);
b = state->padding | (((uint64_t) state->inlen) << 56);
#ifdef DEBUG
printf("(%3zu) v0 %08x %08x\n", state->inlen, (uint32_t) (state->v0 >> 32), (uint32_t) state->v0);
printf("(%3zu) v1 %08x %08x\n", state->inlen, (uint32_t) (state->v1 >> 32), (uint32_t) state->v1);
printf("(%3zu) v2 %08x %08x\n", state->inlen, (uint32_t) (state->v2 >> 32), (uint32_t) state->v2);
printf("(%3zu) v3 %08x %08x\n", state->inlen, (uint32_t) (state->v3 >> 32), (uint32_t) state->v3);
printf("(%3zu) padding %08x %08x\n", state->inlen, (uint32_t) (state->padding >> 32), (uint32_t) state->padding);
#endif
state->v3 ^= b;
sipround(state);
sipround(state);
state->v0 ^= b;
#ifdef DEBUG
printf("(%3zu) v0 %08x %08x\n", state->inlen, (uint32_t) (state->v0 >> 32), (uint32_t) state->v0);
printf("(%3zu) v1 %08x %08x\n", state->inlen, (uint32_t) (state->v1 >> 32), (uint32_t) state->v1);
printf("(%3zu) v2 %08x %08x\n", state->inlen, (uint32_t) (state->v2 >> 32), (uint32_t) state->v2);
printf("(%3zu) v3 %08x %08x\n", state->inlen, (uint32_t) (state->v3 >> 32), (uint32_t) state->v3);
#endif
state->v2 ^= 0xff;
sipround(state);
sipround(state);
sipround(state);
sipround(state);
return state->v0 ^ state->v1 ^ state->v2 ^ state->v3;
}
uint64_t siphash24(const void *in, size_t inlen, const uint8_t k[16]) {
struct siphash state;
assert(in);
assert(k);
siphash24_init(&state, k);
siphash24_compress(in, inlen, &state);
return siphash24_finalize(&state);
}
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