Some of the siphas_*b() functions return 64-bit results, others 32-bit
results, with no obvious pattern. siphash_32b() also appears to do this
incorrectly - taking the 64-bit hash value and simply returning it
truncated, rather than folding the two halves together.
Since SipHash proper is defined to give a 64-bit hash, make all of them
return 64-bit results. In the one caller which needs a 32-bit value,
tcp_seq_init() do the fold down to 32-bits ourselves.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
siphash.c | 17 +++++++----------
siphash.h | 6 +++---
tcp.c | 7 ++++---
3 files changed, 14 insertions(+), 16 deletions(-)
diff --git a/siphash.c b/siphash.c
index e266e15..20009fe 100644
--- a/siphash.c
+++ b/siphash.c
@@ -61,7 +61,6 @@
uint64_t v[4] = { 0x736f6d6570736575ULL, 0x646f72616e646f6dULL, \
0x6c7967656e657261ULL, 0x7465646279746573ULL }; \
uint64_t b = (uint64_t)(len) << 56; \
- uint32_t ret; \
int __i; \
\
do { \
@@ -93,8 +92,6 @@
v[2] ^= 0xff; \
SIPROUND(4); \
b = (v[0] ^ v[1]) ^ (v[2] ^ v[3]); \
- ret = (uint32_t)(b >> 32) ^ (uint32_t)b; \
- (void)ret; \
} while (0)
/**
@@ -132,12 +129,12 @@ uint64_t siphash_8b(const uint8_t *in, const uint64_t *k)
* @in: Input data (two addresses, two ports)
* @k: Hash function key, 128 bits
*
- * Return: 32 bits obtained by XORing the two halves of the 64-bit hash output
+ * Return: the 64-bit hash output
*/
/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
__attribute__((optimize("-fno-strict-aliasing"))) /* See siphash_8b() */
/* cppcheck-suppress unusedFunction */
-uint32_t siphash_12b(const uint8_t *in, const uint64_t *k)
+uint64_t siphash_12b(const uint8_t *in, const uint64_t *k)
{
uint32_t *in32 = (uint32_t *)in;
uint64_t combined;
@@ -151,7 +148,7 @@ uint32_t siphash_12b(const uint8_t *in, const uint64_t *k)
b |= *(in32 + 2);
POSTAMBLE;
- return ret;
+ return b;
}
/**
@@ -194,7 +191,7 @@ uint64_t siphash_20b(const uint8_t *in, const uint64_t *k)
/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
__attribute__((optimize("-fno-strict-aliasing"))) /* See siphash_8b() */
/* cppcheck-suppress unusedFunction */
-uint32_t siphash_32b(const uint8_t *in, const uint64_t *k)
+uint64_t siphash_32b(const uint8_t *in, const uint64_t *k)
{
uint64_t *in64 = (uint64_t *)in;
int i;
@@ -217,11 +214,11 @@ uint32_t siphash_32b(const uint8_t *in, const uint64_t *k)
* @in: Input data (two addresses, two ports)
* @k: Hash function key, 128 bits
*
- * Return: 32 bits obtained by XORing the two halves of the 64-bit hash output
+ * Return: the 64-bit hash output
*/
/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
__attribute__((optimize("-fno-strict-aliasing"))) /* See siphash_8b() */
-uint32_t siphash_36b(const uint8_t *in, const uint64_t *k)
+uint64_t siphash_36b(const uint8_t *in, const uint64_t *k)
{
uint32_t *in32 = (uint32_t *)in;
int i;
@@ -239,5 +236,5 @@ uint32_t siphash_36b(const uint8_t *in, const uint64_t *k)
b |= *in32;
POSTAMBLE;
- return ret;
+ return b;
}
diff --git a/siphash.h b/siphash.h
index 5b0d0c3..de04c56 100644
--- a/siphash.h
+++ b/siphash.h
@@ -7,9 +7,9 @@
#define SIPHASH_H
uint64_t siphash_8b(const uint8_t *in, const uint64_t *k);
-uint32_t siphash_12b(const uint8_t *in, const uint64_t *k);
+uint64_t siphash_12b(const uint8_t *in, const uint64_t *k);
uint64_t siphash_20b(const uint8_t *in, const uint64_t *k);
-uint32_t siphash_32b(const uint8_t *in, const uint64_t *k);
-uint32_t siphash_36b(const uint8_t *in, const uint64_t *k);
+uint64_t siphash_32b(const uint8_t *in, const uint64_t *k);
+uint64_t siphash_36b(const uint8_t *in, const uint64_t *k);
#endif /* SIPHASH_H */
diff --git a/tcp.c b/tcp.c
index dd3142d..9f28020 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1826,7 +1826,8 @@ static void tcp_seq_init(const struct ctx *c, struct tcp_tap_conn
*conn,
.srcport = conn->fport,
.dstport = conn->eport,
};
- uint32_t ns, seq = 0;
+ uint64_t hash;
+ uint32_t ns;
if (CONN_V4(conn))
inany_from_af(&aany, AF_INET, &c->ip4.addr);
@@ -1834,12 +1835,12 @@ static void tcp_seq_init(const struct ctx *c, struct tcp_tap_conn
*conn,
inany_from_af(&aany, AF_INET6, &c->ip6.addr);
in.dst = aany;
- seq = siphash_36b((uint8_t *)&in, c->tcp.hash_secret);
+ hash = siphash_36b((uint8_t *)&in, c->tcp.hash_secret);
/* 32ns ticks, overflows 32 bits every 137s */
ns = (now->tv_sec * 1000000000 + now->tv_nsec) >> 5;
- conn->seq_to_tap = seq + ns;
+ conn->seq_to_tap = ((uint32_t)(hash >> 32) ^ (uint32_t)hash) + ns;
}
/**
--
2.41.0