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| author | David Gibson <david@gibson.dropbear.id.au> | 2023-09-28 11:20:54 +1000 |
|---|---|---|
| committer | Stefano Brivio <sbrivio@redhat.com> | 2023-09-30 12:40:34 +0200 |
| commit | f7b2be2d2121c403e39586d75af8c34ec545df21 (patch) | |
| tree | cfd8eb8c6f0bc4b9996983659751fec58eef3d43 /siphash.c | |
| parent | ca6e94702cfbe29b279cf18f39a0fe492fae6f83 (diff) | |
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siphash: Make sip round calculations an inline function rather than macro
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>
Diffstat (limited to 'siphash.c')
| -rw-r--r-- | siphash.c | 51 |
1 files changed, 29 insertions, 22 deletions
@@ -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; } |