From ca6e94702cfbe29b279cf18f39a0fe492fae6f83 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 28 Sep 2023 11:20:53 +1000 Subject: siphash: Make siphash functions consistently return 64-bit results 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 Signed-off-by: Stefano Brivio --- tcp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'tcp.c') diff --git a/tcp.c b/tcp.c index 2933123..19baba5 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; } /** -- cgit v1.2.3