/*-
* Copyright (c) 1998 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by the 3am Software Foundry ("3am"). It was developed by Matt Thomas.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/ip_flow.h>
#define IPFLOW_TIMER (5 * PR_SLOWHZ)
#define IPFLOW_HASHBITS 6 /* should not be a multiple of 8 */
#define IPFLOW_HASHSIZE (1 << IPFLOW_HASHBITS)
static LIST_HEAD(ipflowhead, ipflow) ipflows[IPFLOW_HASHSIZE];
static int ipflow_inuse;
#define IPFLOW_MAX 256
static int ipflow_active = 0;
SYSCTL_INT(_net_inet_ip, IPCTL_FASTFORWARDING, fastforwarding, CTLFLAG_RW,
&ipflow_active, 0, "Enable flow-based IP forwarding");
static MALLOC_DEFINE(M_IPFLOW, "ip_flow", "IP flow");
static unsigned
ipflow_hash(
struct in_addr dst,
struct in_addr src,
unsigned tos)
{
unsigned hash = tos;
int idx;
for (idx = 0; idx < 32; idx += IPFLOW_HASHBITS)
hash += (dst.s_addr >> (32 - idx)) + (src.s_addr >> idx);
return hash & (IPFLOW_HASHSIZE-1);
}
static struct ipflow *
ipflow_lookup(
const struct ip *ip)
{
unsigned hash;
struct ipflow *ipf;
hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos);
ipf = LIST_FIRST(&ipflows[hash]);
while (ipf != NULL) {
if (ip->ip_dst.s_addr == ipf->ipf_dst.s_addr
&& ip->ip_src.s_addr == ipf->ipf_src.s_addr
&& ip->ip_tos == ipf->ipf_tos)
break;
ipf = LIST_NEXT(ipf, ipf_next);
}
return ipf;
}
int
ipflow_fastforward(
struct mbuf *m)
{
struct ip *ip;
struct ipflow *ipf;
struct rtentry *rt;
int error;
/*
* Are we forwarding packets? Big enough for an IP packet?
*/
if (!ipforwarding || !ipflow_active || m->m_len < sizeof(struct ip))
return 0;
/*
* IP header with no option and valid version and length
*/
ip = mtod(m, struct ip *);
if (ip->ip_v != IPVERSION || ip->ip_hl != (sizeof(struct ip) >> 2)
|| ntohs(ip->ip_len) > m->m_pkthdr.len)
return 0;
/*
* Find a flow.
*/
if ((ipf = ipflow_lookup(ip)) == NULL)
return 0;
/*
* Route and interface still up?
*/
rt = ipf->ipf_ro.ro_rt;
if ((rt->rt_flags & RTF_UP) == 0 || (rt->rt_ifp->if_flags & IFF_UP) == 0)
return 0;
/*
* Packet size OK? TTL?
*/
if (m->m_pkthdr.len > rt->rt_ifp->if_mtu || ip->ip_ttl <= IPTTLDEC)
return 0;
/*
* Everything checks out and so we can forward this packet.
* Modify the TTL and incrementally change the checksum.
*/
ip->ip_ttl -= IPTTLDEC;
if (ip->ip_sum >= htons(0xffff - (IPTTLDEC << 8))) {
ip->ip_sum += htons(IPTTLDEC << 8) + 1;
} else {
ip->ip_sum += htons(IPTTLDEC << 8);
}
/*
* Send the packet on its way. All we can get back is ENOBUFS
*/
ipf->ipf_uses++;
ipf->ipf_timer = IPFLOW_TIMER;
if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, &ipf->ipf_ro.ro_dst, rt)) != 0) {
if (error == ENOBUFS)
ipf->ipf_dropped++;
else
ipf->ipf_errors++;
}
return 1;
}
static void
ipflow_addstats(
struct ipflow *ipf)
{
ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses;
ipstat.ips_cantforward += ipf->ipf_errors + ipf->ipf_dropped;
ipstat.ips_forward += ipf->ipf_uses;
ipstat.ips_fastforward += ipf->ipf_uses;
}
static void
ipflow_free(
struct ipflow *ipf)
{
int s;
/*
* Remove the flow from the hash table (at elevated IPL).
* Once it's off the list, we can deal with it at normal
* network IPL.
*/
s = splimp();
LIST_REMOVE(ipf, ipf_next);
splx(s);
ipflow_addstats(ipf);
RTFREE(ipf->ipf_ro.ro_rt);
ipflow_inuse--;
FREE(ipf, M_IPFLOW);
}
static struct ipflow *
ipflow_reap(
void)
{
struct ipflow *ipf, *maybe_ipf = NULL;
int idx;
int s;
for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) {
ipf = LIST_FIRST(&ipflows[idx]);
while (ipf != NULL) {
/*
* If this no longer points to a valid route
* reclaim it.
*/
if ((ipf->ipf_ro.ro_rt->rt_flags & RTF_UP) == 0)
goto done;
/*
* choose the one that's been least recently used
* or has had the least uses in the last 1.5
* intervals.
*/
if (maybe_ipf == NULL
|| ipf->ipf_timer < maybe_ipf->ipf_timer
|| (ipf->ipf_timer == maybe_ipf->ipf_timer
&& ipf->ipf_last_uses + ipf->ipf_uses <
maybe_ipf->ipf_last_uses +
maybe_ipf->ipf_uses))
maybe_ipf = ipf;
ipf = LIST_NEXT(ipf, ipf_next);
}
}
ipf = maybe_ipf;
done:
/*
* Remove the entry from the flow table.
*/
s = splimp();
LIST_REMOVE(ipf, ipf_next);
splx(s);
ipflow_addstats(ipf);
RTFREE(ipf->ipf_ro.ro_rt);
return ipf;
}
void
ipflow_slowtimo(
void)
{
struct ipflow *ipf;
int idx;
for (idx = 0; idx < IPFLOW_HASHSIZE; idx++) {
ipf = LIST_FIRST(&ipflows[idx]);
while (ipf != NULL) {
struct ipflow *next_ipf = LIST_NEXT(ipf, ipf_next);
if (--ipf->ipf_timer == 0) {
ipflow_free(ipf);
} else {
ipf->ipf_last_uses = ipf->ipf_uses;
ipf->ipf_ro.ro_rt->rt_use += ipf->ipf_uses;
ipstat.ips_forward += ipf->ipf_uses;
ipstat.ips_fastforward += ipf->ipf_uses;
ipf->ipf_uses = 0;
}
ipf = next_ipf;
}
}
}
void
ipflow_create(
const struct route *ro,
struct mbuf *m)
{
const struct ip *const ip = mtod(m, struct ip *);
struct ipflow *ipf;
unsigned hash;
int s;
/*
* Don't create cache entries for ICMP messages.
*/
if (!ipflow_active || ip->ip_p == IPPROTO_ICMP)
return;
/*
* See if an existing flow struct exists. If so remove it from it's
* list and free the old route. If not, try to malloc a new one
* (if we aren't at our limit).
*/
ipf = ipflow_lookup(ip);
if (ipf == NULL) {
if (ipflow_inuse == IPFLOW_MAX) {
ipf = ipflow_reap();
} else {
ipf = (struct ipflow *) malloc(sizeof(*ipf), M_IPFLOW,
M_NOWAIT);
if (ipf == NULL)
return;
ipflow_inuse++;
}
bzero((caddr_t) ipf, sizeof(*ipf));
} else {
s = splimp();
LIST_REMOVE(ipf, ipf_next);
splx(s);
ipflow_addstats(ipf);
RTFREE(ipf->ipf_ro.ro_rt);
ipf->ipf_uses = ipf->ipf_last_uses = 0;
ipf->ipf_errors = ipf->ipf_dropped = 0;
}
/*
* Fill in the updated information.
*/
ipf->ipf_ro = *ro;
ro->ro_rt->rt_refcnt++;
ipf->ipf_dst = ip->ip_dst;
ipf->ipf_src = ip->ip_src;
ipf->ipf_tos = ip->ip_tos;
ipf->ipf_timer = IPFLOW_TIMER;
/*
* Insert into the approriate bucket of the flow table.
*/
hash = ipflow_hash(ip->ip_dst, ip->ip_src, ip->ip_tos);
s = splimp();
LIST_INSERT_HEAD(&ipflows[hash], ipf, ipf_next);
splx(s);
}
