dd35516544
PR: kern/11197 Submitted by: Adrian Chadd <adrian@FreeBSD.org> Reviewed by: billf(spelling/style/minor nits) Looked at by: bde(style)
328 lines
8.3 KiB
C
328 lines
8.3 KiB
C
/*-
|
||
* 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.
|
||
*
|
||
* $Id: ip_flow.c,v 1.7 1999/04/11 02:50:42 eivind Exp $
|
||
*/
|
||
|
||
#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);
|
||
}
|