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siphash: Make sip round calculations an inline function rather than macro

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The SIPROUND(n) macro implements n rounds of SipHash shuffling.  It relies
on 'v' and '__i' variables being available in the context it's used in
which isn't great hygeine.  Replace it with an inline function instead.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2023-09-28 11:20:54 +10:00 committed by Stefano Brivio
parent ca6e94702c
commit f7b2be2d21
1 changed files with 29 additions and 22 deletions
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51
siphash.c
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@ -68,29 +68,36 @@
v[__i] = k[__i % 2]; \
} while (0)
#define SIPROUND(n) \
do { \
for (__i = 0; __i < (n); __i++) { \
v[0] += v[1]; \
v[1] = ROTL(v[1], 13) ^ v[0]; \
v[0] = ROTL(v[0], 32); \
v[2] += v[3]; \
v[3] = ROTL(v[3], 16) ^ v[2]; \
v[0] += v[3]; \
v[3] = ROTL(v[3], 21) ^ v[0]; \
v[2] += v[1]; \
v[1] = ROTL(v[1], 17) ^ v[2]; \
v[2] = ROTL(v[2], 32); \
} \
} while (0)
/**
* sipround() - Perform rounds of SipHash scrambling
* @v: siphash state (4 x 64-bit integers)
* @n: Number of rounds to apply
*/
static inline void sipround(uint64_t *v, int n)
{
int i;
for (i = 0; i < n; i++) {
v[0] += v[1];
v[1] = ROTL(v[1], 13) ^ v[0];
v[0] = ROTL(v[0], 32);
v[2] += v[3];
v[3] = ROTL(v[3], 16) ^ v[2];
v[0] += v[3];
v[3] = ROTL(v[3], 21) ^ v[0];
v[2] += v[1];
v[1] = ROTL(v[1], 17) ^ v[2];
v[2] = ROTL(v[2], 32);
}
}
#define POSTAMBLE \
do { \
v[3] ^= b; \
SIPROUND(2); \
sipround(v, 2); \
v[0] ^= b; \
v[2] ^= 0xff; \
SIPROUND(4); \
sipround(v, 4); \
b = (v[0] ^ v[1]) ^ (v[2] ^ v[3]); \
} while (0)
@ -117,7 +124,7 @@ uint64_t siphash_8b(const uint8_t *in, const uint64_t *k)
{
PREAMBLE(8);
v[3] ^= *(uint64_t *)in;
SIPROUND(2);
sipround(v, 2);
v[0] ^= *(uint64_t *)in;
POSTAMBLE;
@ -143,7 +150,7 @@ uint64_t siphash_12b(const uint8_t *in, const uint64_t *k)
PREAMBLE(12);
v[3] ^= combined;
SIPROUND(2);
sipround(v, 2);
v[0] ^= combined;
b |= *(in32 + 2);
POSTAMBLE;
@ -171,7 +178,7 @@ uint64_t siphash_20b(const uint8_t *in, const uint64_t *k)
uint64_t combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
v[3] ^= combined;
SIPROUND(2);
sipround(v, 2);
v[0] ^= combined;
}
@ -200,7 +207,7 @@ uint64_t siphash_32b(const uint8_t *in, const uint64_t *k)
for (i = 0; i < 4; i++, in64++) {
v[3] ^= *in64;
SIPROUND(2);
sipround(v, 2);
v[0] ^= *in64;
}
@ -229,7 +236,7 @@ uint64_t siphash_36b(const uint8_t *in, const uint64_t *k)
uint64_t combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
v[3] ^= combined;
SIPROUND(2);
sipround(v, 2);
v[0] ^= combined;
}