Stuart Henderson(st...@openbsd.org) on 2014.12.11 23:52:44 +0000:
> I'm wondering what reception this will get. It feeds TCP/UDP port
> numbers into the hash for trunk(4) load balancing, so connections
> between a single pair of hosts will get distributed across NICs.
> Taken from FreeBSD r232629, they also added SIOC[CS]LAGGHASH ioctls
> so that the hash type can be configured in ifconfig (l2/l3/l4),
> I haven't done that but could if there's no general objection to
> this.
i like this, and i think it might be good to have it optional in case it
causes problems with other equipment.
Benno
> This method is used on some switches too (e.g. "trunk-load-balance
> L4-based" on HP 2530 and 5400zl).
>
> Index: if_trunk.c
> ===================================================================
> RCS file: /cvs/src/sys/net/if_trunk.c,v
> retrieving revision 1.93
> diff -u -p -r1.93 if_trunk.c
> --- if_trunk.c 4 Dec 2014 00:01:53 -0000 1.93
> +++ if_trunk.c 11 Dec 2014 23:45:20 -0000
> @@ -978,12 +978,23 @@ trunk_hashmbuf(struct mbuf *m, SIPHASH_K
> int off;
> struct ether_header *eh;
> #ifdef INET
> - struct ip *ip, ipbuf;
> + struct ip *ip;
> + u_int32_t *ports;
> + int iphlen;
> #endif
> #ifdef INET6
> u_int32_t flow;
> struct ip6_hdr *ip6, ip6buf;
> #endif
> + union {
> +#ifdef INET
> + struct ip ip;
> +#endif
> +#ifdef INET6
> + struct ip6_hdr ip6;
> +#endif
> + uint32_t port;
> + } buf;
> SIPHASH_CTX ctx;
>
> SipHash24_Init(&ctx, key);
> @@ -1013,10 +1024,25 @@ trunk_hashmbuf(struct mbuf *m, SIPHASH_K
> #ifdef INET
> case ETHERTYPE_IP:
> if ((ip = (struct ip *)
> - trunk_gethdr(m, off, sizeof(*ip), &ipbuf)) == NULL)
> + trunk_gethdr(m, off, sizeof(*ip), &buf)) == NULL)
> return (p);
> SipHash24_Update(&ctx, &ip->ip_src, sizeof(struct in_addr));
> SipHash24_Update(&ctx, &ip->ip_dst, sizeof(struct in_addr));
> +
> + /* l4 hash */
> + switch (ip->ip_p) {
> + case IPPROTO_TCP:
> + case IPPROTO_UDP:
> + iphlen = ip->ip_hl << 2;
> + if (iphlen < sizeof(*ip))
> + break;
> + off += iphlen;
> + ports = (u_int32_t *) trunk_gethdr(m, off,
> sizeof(*ports), &buf);
> + if (ports == NULL)
> + break;
> + SipHash24_Update(&ctx, ports, sizeof(*ports));
> + break;
> + }
> break;
> #endif
> #ifdef INET6
>
--
