NetBSD/sys/netinet6/ip6_flow.c

523 lines
13 KiB
C

/* $NetBSD: ip6_flow.c,v 1.9 2007/08/20 19:42:34 dyoung Exp $ */
/*-
* Copyright (c) 2007 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 Liam J. Foy
* <liamjfoy@netbsd.org> and Matt Thomas <matt@netbsd.org>.
*
* 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.
*
* IPv6 version was developed by Liam J. Foy. Original source existed in IPv4
* format developed by Matt Thomas. Thanks to Joerg Sonnenberger, Matt
* Thomas and Christos Zoulas.
*
* Thanks to Liverpool John Moores University, especially Dr. David Llewellyn-Jones
* for providing resources (to test) and Professor Madjid Merabti.
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/pool.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/pfil.h>
#include <netinet/in.h>
#include <netinet6/in6_var.h>
#include <netinet/in_systm.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
/*
* IPv6 Fast Forward caches/hashes flows from one source to destination.
*
* Upon a successful forward IPv6FF caches and hashes details such as the
* route, source and destination. Once another packet is received matching
* the source and destination the packet is forwarded straight onto if_output
* using the cached details.
*
* Example:
* ether/fddi_input -> ip6flow_fastfoward -> if_output
*/
POOL_INIT(ip6flow_pool, sizeof(struct ip6flow), 0, 0, 0, "ip6flowpl", NULL,
IPL_NET);
LIST_HEAD(ip6flowhead, ip6flow);
/*
* We could use IPv4 defines (IPFLOW_HASHBITS) but we'll
* use our own (possibly for future expansion).
*/
#define IP6FLOW_TIMER (5 * PR_SLOWHZ)
#define IP6FLOW_DEFAULT_HASHSIZE (1 << IP6FLOW_HASHBITS)
static struct ip6flowhead *ip6flowtable = NULL;
static struct ip6flowhead ip6flowlist;
static int ip6flow_inuse;
/*
* Insert an ip6flow into the list.
*/
#define IP6FLOW_INSERT(bucket, ip6f) \
do { \
LIST_INSERT_HEAD((bucket), (ip6f), ip6f_hash); \
LIST_INSERT_HEAD(&ip6flowlist, (ip6f), ip6f_list); \
} while (/*CONSTCOND*/ 0)
/*
* Remove an ip6flow from the list.
*/
#define IP6FLOW_REMOVE(ip6f) \
do { \
LIST_REMOVE((ip6f), ip6f_hash); \
LIST_REMOVE((ip6f), ip6f_list); \
} while (/*CONSTCOND*/ 0)
#ifndef IP6FLOW_DEFAULT
#define IP6FLOW_DEFAULT 256
#endif
int ip6_maxflows = IP6FLOW_DEFAULT;
int ip6_hashsize = IP6FLOW_DEFAULT_HASHSIZE;
/*
* Calculate hash table position.
*/
static size_t
ip6flow_hash(struct ip6_hdr *ip6)
{
size_t hash;
uint32_t dst_sum, src_sum;
size_t idx;
src_sum = ip6->ip6_src.s6_addr32[0] + ip6->ip6_src.s6_addr32[1]
+ ip6->ip6_src.s6_addr32[2] + ip6->ip6_src.s6_addr32[3];
dst_sum = ip6->ip6_dst.s6_addr32[0] + ip6->ip6_dst.s6_addr32[1]
+ ip6->ip6_dst.s6_addr32[2] + ip6->ip6_dst.s6_addr32[3];
hash = ip6->ip6_flow;
for (idx = 0; idx < 32; idx += IP6FLOW_HASHBITS)
hash += (dst_sum >> (32 - idx)) + (src_sum >> idx);
return hash & (ip6_hashsize-1);
}
/*
* Check to see if a flow already exists - if so return it.
*/
static struct ip6flow *
ip6flow_lookup(struct ip6_hdr *ip6)
{
size_t hash;
struct ip6flow *ip6f;
hash = ip6flow_hash(ip6);
LIST_FOREACH(ip6f, &ip6flowtable[hash], ip6f_hash) {
if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &ip6f->ip6f_dst)
&& IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &ip6f->ip6f_src)
&& ip6f->ip6f_flow == ip6->ip6_flow) {
/* A cached flow has been found. */
return ip6f;
}
}
return NULL;
}
/*
* Allocate memory and initialise lists. This function is called
* from ip6_init and called there after to resize the hash table.
* If a newly sized table cannot be malloc'ed we just continue
* to use the old one.
*/
int
ip6flow_init(int table_size)
{
struct ip6flowhead *new_table;
size_t i;
new_table = (struct ip6flowhead *)malloc(sizeof(struct ip6flowhead) *
table_size, M_RTABLE, M_NOWAIT);
if (new_table == NULL)
return 1;
if (ip6flowtable != NULL)
free(ip6flowtable, M_RTABLE);
ip6flowtable = new_table;
ip6_hashsize = table_size;
LIST_INIT(&ip6flowlist);
for (i = 0; i < ip6_hashsize; i++)
LIST_INIT(&ip6flowtable[i]);
return 0;
}
/*
* IPv6 Fast Forward routine. Attempt to forward the packet -
* if any problems are found return to the main IPv6 input
* routine to deal with.
*/
int
ip6flow_fastforward(struct mbuf *m)
{
struct ip6flow *ip6f;
struct ip6_hdr *ip6;
struct rtentry *rt;
const struct sockaddr *dst;
int error;
/*
* Are we forwarding packets and have flows?
*/
if (!ip6_forwarding || ip6flow_inuse == 0)
return 0;
/*
* At least size of IPv6 Header?
*/
if (m->m_len < sizeof(struct ip6_hdr))
return 0;
/*
* Was packet received as a link-level multicast or broadcast?
* If so, don't try to fast forward.
*/
if ((m->m_flags & (M_BCAST|M_MCAST)) != 0)
return 0;
if (IP6_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
if ((m = m_copyup(m, sizeof(struct ip6_hdr),
(max_linkhdr + 3) & ~3)) == NULL) {
return 0;
}
} else if (__predict_false(m->m_len < sizeof(struct ip6_hdr))) {
if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
return 0;
}
}
ip6 = mtod(m, struct ip6_hdr *);
if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
/* Bad version. */
return 0;
}
/*
* If we have a hop-by-hop extension we must process it.
* We just leave this up to ip6_input to deal with.
*/
if (ip6->ip6_nxt == IPPROTO_HOPOPTS)
return 0;
/*
* Attempt to find a flow.
*/
if ((ip6f = ip6flow_lookup(ip6)) == NULL) {
/* No flow found. */
return 0;
}
/*
* Route and interface still up?
*/
if (rtcache_down(&ip6f->ip6f_ro) ||
(rt = ip6f->ip6f_ro.ro_rt) == NULL ||
(rt->rt_ifp->if_flags & IFF_UP) == 0) {
/* Route or interface is down */
return 0;
}
/*
* Packet size greater than MTU?
*/
if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) {
/* Return to main IPv6 input function. */
return 0;
}
if (ip6->ip6_hlim <= IPV6_HLIMDEC)
return 0;
/* Decrement hop limit (same as TTL) */
ip6->ip6_hlim -= IPV6_HLIMDEC;
if (rt->rt_flags & RTF_GATEWAY)
dst = rt->rt_gateway;
else
dst = rtcache_getdst(&ip6f->ip6f_ro);
PRT_SLOW_ARM(ip6f->ip6f_timer, IP6FLOW_TIMER);
ip6f->ip6f_uses++;
/* Send on its way - straight to the interface output routine. */
if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, dst, rt)) != 0) {
ip6f->ip6f_dropped++;
} else {
ip6f->ip6f_forwarded++;
}
return 1;
}
/*
* Add the IPv6 flow statistics to the main IPv6 statistics.
*/
static void
ip6flow_addstats(struct ip6flow *ip6f)
{
if (!rtcache_down(&ip6f->ip6f_ro) && ip6f->ip6f_ro.ro_rt != NULL)
ip6f->ip6f_ro.ro_rt->rt_use += ip6f->ip6f_uses;
ip6stat.ip6s_fastforwardflows = ip6flow_inuse;
ip6stat.ip6s_cantforward += ip6f->ip6f_dropped;
ip6stat.ip6s_odropped += ip6f->ip6f_dropped;
ip6stat.ip6s_total += ip6f->ip6f_uses;
ip6stat.ip6s_forward += ip6f->ip6f_forwarded;
ip6stat.ip6s_fastforward += ip6f->ip6f_forwarded;
}
/*
* Add statistics and free the flow.
*/
static void
ip6flow_free(struct ip6flow *ip6f)
{
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 = splnet();
IP6FLOW_REMOVE(ip6f);
splx(s);
ip6flow_inuse--;
ip6flow_addstats(ip6f);
rtcache_free(&ip6f->ip6f_ro);
pool_put(&ip6flow_pool, ip6f);
}
/*
* Reap one or more flows - ip6flow_reap may remove
* multiple flows if net.inet6.ip6.maxflows is reduced.
*/
struct ip6flow *
ip6flow_reap(int just_one)
{
while (just_one || ip6flow_inuse > ip6_maxflows) {
struct ip6flow *ip6f, *maybe_ip6f = NULL;
int s;
ip6f = LIST_FIRST(&ip6flowlist);
while (ip6f != NULL) {
/*
* If this no longer points to a valid route -
* reclaim it.
*/
if (rtcache_down(&ip6f->ip6f_ro) ||
ip6f->ip6f_ro.ro_rt == NULL)
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_ip6f == NULL ||
ip6f->ip6f_timer < maybe_ip6f->ip6f_timer ||
(ip6f->ip6f_timer == maybe_ip6f->ip6f_timer &&
ip6f->ip6f_last_uses + ip6f->ip6f_uses <
maybe_ip6f->ip6f_last_uses +
maybe_ip6f->ip6f_uses))
maybe_ip6f = ip6f;
ip6f = LIST_NEXT(ip6f, ip6f_list);
}
ip6f = maybe_ip6f;
done:
/*
* Remove the entry from the flow table
*/
s = splnet();
IP6FLOW_REMOVE(ip6f);
splx(s);
rtcache_free(&ip6f->ip6f_ro);
if (just_one) {
ip6flow_addstats(ip6f);
return ip6f;
}
ip6flow_inuse--;
ip6flow_addstats(ip6f);
pool_put(&ip6flow_pool, ip6f);
}
return NULL;
}
void
ip6flow_slowtimo(void)
{
struct ip6flow *ip6f, *next_ip6f;
for (ip6f = LIST_FIRST(&ip6flowlist); ip6f != NULL; ip6f = next_ip6f) {
next_ip6f = LIST_NEXT(ip6f, ip6f_list);
if (PRT_SLOW_ISEXPIRED(ip6f->ip6f_timer) ||
rtcache_down(&ip6f->ip6f_ro) ||
ip6f->ip6f_ro.ro_rt == NULL) {
ip6flow_free(ip6f);
} else {
ip6f->ip6f_last_uses = ip6f->ip6f_uses;
ip6flow_addstats(ip6f);
ip6f->ip6f_uses = 0;
ip6f->ip6f_dropped = 0;
ip6f->ip6f_forwarded = 0;
}
}
}
/*
* We have successfully forwarded a packet using the normal
* IPv6 stack. Now create/update a flow.
*/
void
ip6flow_create(const struct route *ro, struct mbuf *m)
{
struct ip6_hdr *ip6;
struct ip6flow *ip6f;
size_t hash;
int s;
ip6 = mtod(m, struct ip6_hdr *);
/*
* If IPv6 Fast Forward is disabled, don't create a flow.
* It can be disabled by setting net.inet6.ip6.maxflows to 0.
*
* Don't create a flow for ICMPv6 messages.
*/
if (ip6_maxflows == 0 || ip6->ip6_nxt == IPPROTO_IPV6_ICMP)
return;
/*
* See if an existing flow exists. If so:
* - Remove the flow
* - Add flow statistics
* - Free the route
* - Reset statistics
*
* If a flow doesn't exist allocate a new one if
* ip6_maxflows hasn't reached its limit. If it has
* been reached, reap some flows.
*/
ip6f = ip6flow_lookup(ip6);
if (ip6f == NULL) {
if (ip6flow_inuse >= ip6_maxflows) {
ip6f = ip6flow_reap(1);
} else {
ip6f = pool_get(&ip6flow_pool, PR_NOWAIT);
if (ip6f == NULL)
return;
ip6flow_inuse++;
}
memset(ip6f, 0, sizeof(*ip6f));
} else {
s = splnet();
IP6FLOW_REMOVE(ip6f);
splx(s);
ip6flow_addstats(ip6f);
rtcache_free(&ip6f->ip6f_ro);
ip6f->ip6f_uses = 0;
ip6f->ip6f_last_uses = 0;
ip6f->ip6f_dropped = 0;
ip6f->ip6f_forwarded = 0;
}
/*
* Fill in the updated/new details.
*/
rtcache_copy(&ip6f->ip6f_ro, ro);
ip6f->ip6f_dst = ip6->ip6_dst;
ip6f->ip6f_src = ip6->ip6_src;
ip6f->ip6f_flow = ip6->ip6_flow;
PRT_SLOW_ARM(ip6f->ip6f_timer, IP6FLOW_TIMER);
ip6f->ip6f_start = time_uptime;
/*
* Insert into the approriate bucket of the flow table.
*/
hash = ip6flow_hash(ip6);
s = splnet();
IP6FLOW_INSERT(&ip6flowtable[hash], ip6f);
splx(s);
}
/*
* Invalidate/remove all flows - if new_size is positive we
* resize the hash table.
*/
int
ip6flow_invalidate_all(int new_size)
{
struct ip6flow *ip6f, *next_ip6f;
int s, error;
error = 0;
s = splnet();
for (ip6f = LIST_FIRST(&ip6flowlist); ip6f != NULL; ip6f = next_ip6f) {
next_ip6f = LIST_NEXT(ip6f, ip6f_list);
ip6flow_free(ip6f);
}
if (new_size)
error = ip6flow_init(new_size);
splx(s);
return error;
}