hash.h

/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2020 Authors of Cilium */

#ifndef __HASH_H_
#define __HASH_H_

#include "common.h"
#include "jhash.h"

/* The daddr is explicitly excluded from the hash here in order to allow for
 * backend selection to choose the same backend even on different service VIPs.
 */
static __always_inline __u32 hash_from_tuple_v4(const struct ipv4_ct_tuple *tuple)
{
	return jhash_3words(tuple->saddr,
			    ((__u32)tuple->dport << 16) | tuple->sport,
			    tuple->nexthdr, HASH_INIT4_SEED);
}

static __always_inline __u32 hash_from_tuple_v6(const struct ipv6_ct_tuple *tuple)
{
	__u32 a, b, c;

	a = tuple->saddr.p1;
	b = tuple->saddr.p2;
	c = tuple->saddr.p3;
	__jhash_mix(a, b, c);
	a += tuple->saddr.p4;
	b += ((__u32)tuple->dport << 16) | tuple->sport;
	c += tuple->nexthdr;
	__jhash_mix(a, b, c);
	a += HASH_INIT6_SEED;
	__jhash_final(a, b, c);
	return c;
}

#endif /* __HASH_H_ */