/* $OpenBSD: if_trunk.c,v 1.30 2007/01/31 06:20:19 reyk Exp $ */
/*
* Copyright (c) 2005, 2006 Reyk Floeter <reyk@openbsd.org>
* Copyright (c) 2007 Andrew Thompson <thompsa@FreeBSD.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/fnv_hash.h>
#include <net/ethernet.h>
#if defined(INET) || defined(INET6)
#include <netinet/in.h>
#endif
#ifdef INET
#include <netinet/ip.h>
#endif
#ifdef INET6
#include <netinet/ip6.h>
#endif
static const void *
m_ether_tcpip_hash_gethdr(const struct mbuf *m, const u_int off,
const u_int len, void *buf)
{
if (m->m_pkthdr.len < (off + len)) {
return (NULL);
} else if (m->m_len < (off + len)) {
m_copydata(m, off, len, buf);
return (buf);
}
return (mtod(m, char *) + off);
}
uint32_t
m_ether_tcpip_hash_init(void)
{
uint32_t seed;
seed = arc4random();
return (fnv_32_buf(&seed, sizeof(seed), FNV1_32_INIT));
}
uint32_t
m_ether_tcpip_hash(const uint32_t flags, const struct mbuf *m,
const uint32_t key)
{
union {
#ifdef INET
struct ip ip;
#endif
#ifdef INET6
struct ip6_hdr ip6;
#endif
struct ether_vlan_header vlan;
uint32_t port;
} buf;
struct ether_header *eh;
const struct ether_vlan_header *vlan;
#ifdef INET
const struct ip *ip;
#endif
#ifdef INET6
const struct ip6_hdr *ip6;
#endif
uint32_t p;
int off;
uint16_t etype;
p = key;
off = sizeof(*eh);
if (m->m_len < off)
goto done;
eh = mtod(m, struct ether_header *);
etype = ntohs(eh->ether_type);
if (flags & MBUF_HASHFLAG_L2) {
p = fnv_32_buf(&eh->ether_shost, ETHER_ADDR_LEN, p);
p = fnv_32_buf(&eh->ether_dhost, ETHER_ADDR_LEN, p);
}
/* Special handling for encapsulating VLAN frames */
if ((m->m_flags & M_VLANTAG) && (flags & MBUF_HASHFLAG_L2)) {
p = fnv_32_buf(&m->m_pkthdr.ether_vtag,
sizeof(m->m_pkthdr.ether_vtag), p);
} else if (etype == ETHERTYPE_VLAN) {
vlan = m_ether_tcpip_hash_gethdr(m, off, sizeof(*vlan), &buf);
if (vlan == NULL)
goto done;
if (flags & MBUF_HASHFLAG_L2)
p = fnv_32_buf(&vlan->evl_tag, sizeof(vlan->evl_tag), p);
etype = ntohs(vlan->evl_proto);
off += sizeof(*vlan) - sizeof(*eh);
}
switch (etype) {
#ifdef INET
case ETHERTYPE_IP:
ip = m_ether_tcpip_hash_gethdr(m, off, sizeof(*ip), &buf);
if (ip == NULL)
break;
if (flags & MBUF_HASHFLAG_L3) {
p = fnv_32_buf(&ip->ip_src, sizeof(struct in_addr), p);
p = fnv_32_buf(&ip->ip_dst, sizeof(struct in_addr), p);
}
if (flags & MBUF_HASHFLAG_L4) {
const uint32_t *ports;
int iphlen;
switch (ip->ip_p) {
case IPPROTO_TCP:
case IPPROTO_UDP:
case IPPROTO_SCTP:
iphlen = ip->ip_hl << 2;
if (iphlen < sizeof(*ip))
break;
off += iphlen;
ports = m_ether_tcpip_hash_gethdr(m,
off, sizeof(*ports), &buf);
if (ports == NULL)
break;
p = fnv_32_buf(ports, sizeof(*ports), p);
break;
default:
break;
}
}
break;
#endif
#ifdef INET6
case ETHERTYPE_IPV6:
ip6 = m_ether_tcpip_hash_gethdr(m, off, sizeof(*ip6), &buf);
if (ip6 == NULL)
break;
if (flags & MBUF_HASHFLAG_L3) {
p = fnv_32_buf(&ip6->ip6_src, sizeof(struct in6_addr), p);
p = fnv_32_buf(&ip6->ip6_dst, sizeof(struct in6_addr), p);
}
if (flags & MBUF_HASHFLAG_L4) {
uint32_t flow;
/* IPv6 flow label */
flow = ip6->ip6_flow & IPV6_FLOWLABEL_MASK;
p = fnv_32_buf(&flow, sizeof(flow), p);
}
break;
#endif
default:
break;
}
done:
return (p);
}
