diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index 72bc68fef48a..109fbf620ad7 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -35,13 +35,43 @@ u32 inet6_ehashfn(const struct net *net, const struct in6_addr *laddr, const u16 lport, const struct in6_addr *faddr, const __be16 fport) { - u32 lhash, fhash; + u32 a, b, c; - lhash = (__force u32)laddr->s6_addr32[3]; - fhash = __ipv6_addr_jhash(faddr, tcp_ipv6_hash_secret); + /* + * Please look at jhash() implementation for reference. + * Hash laddr + faddr + lport/fport + net_hash_mix. + * Notes: + * We combine laddr[0] (high order 32 bits of local address) + * with net_hash_mix() to avoid using __jhash_final(a, b, c). + * + * We do not include JHASH_INITVAL + 36 contribution + * to initial values of a, b, c. + */ - return lport + __inet6_ehashfn(lhash, 0, fhash, fport, - inet6_ehash_secret + net_hash_mix(net)); + a = b = c = tcp_ipv6_hash_secret; + + a += (__force u32)laddr->s6_addr32[0] ^ net_hash_mix(net); + b += (__force u32)laddr->s6_addr32[1]; + c += (__force u32)laddr->s6_addr32[2]; + __jhash_mix(a, b, c); + + a += (__force u32)laddr->s6_addr32[3]; + b += (__force u32)faddr->s6_addr32[0]; + c += (__force u32)faddr->s6_addr32[1]; + __jhash_mix(a, b, c); + + a += (__force u32)faddr->s6_addr32[2]; + b += (__force u32)faddr->s6_addr32[3]; + c += (__force u32)fport; + __jhash_mix(a, b, c); + + /* Note: We need to add @lport instead of fully hashing it. + * See commits 9544d60a2605 ("inet: change lport contribution + * to inet_ehashfn() and inet6_ehashfn()") and d4438ce68bf1 + * ("inet: call inet6_ehashfn() once from inet6_hash_connect()") + * for references. + */ + return lport + c; } EXPORT_SYMBOL_GPL(inet6_ehashfn);