464 lines
13 KiB
C
464 lines
13 KiB
C
/* $NetBSD: ip6_forward.c,v 1.70 2012/03/22 20:34:40 drochner Exp $ */
|
|
/* $KAME: ip6_forward.c,v 1.109 2002/09/11 08:10:17 sakane Exp $ */
|
|
|
|
/*
|
|
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
|
|
* All rights reserved.
|
|
*
|
|
* 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__KERNEL_RCSID(0, "$NetBSD: ip6_forward.c,v 1.70 2012/03/22 20:34:40 drochner Exp $");
|
|
|
|
#include "opt_gateway.h"
|
|
#include "opt_ipsec.h"
|
|
#include "opt_pfil_hooks.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/errno.h>
|
|
#include <sys/time.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/syslog.h>
|
|
|
|
#include <net/if.h>
|
|
#include <net/route.h>
|
|
|
|
#include <netinet/in.h>
|
|
#include <netinet/in_var.h>
|
|
#include <netinet/ip_var.h>
|
|
#include <netinet/ip6.h>
|
|
#include <netinet6/ip6_var.h>
|
|
#include <netinet6/ip6_private.h>
|
|
#include <netinet6/scope6_var.h>
|
|
#include <netinet/icmp6.h>
|
|
#include <netinet6/nd6.h>
|
|
|
|
#ifdef FAST_IPSEC
|
|
#include <netipsec/ipsec.h>
|
|
#include <netipsec/ipsec6.h>
|
|
#include <netipsec/key.h>
|
|
#include <netipsec/xform.h>
|
|
#endif /* FAST_IPSEC */
|
|
|
|
#ifdef PFIL_HOOKS
|
|
#include <net/pfil.h>
|
|
#endif
|
|
|
|
#include <net/net_osdep.h>
|
|
|
|
struct route ip6_forward_rt;
|
|
|
|
#ifdef PFIL_HOOKS
|
|
extern struct pfil_head inet6_pfil_hook; /* XXX */
|
|
#endif
|
|
|
|
/*
|
|
* Forward a packet. If some error occurs return the sender
|
|
* an icmp packet. Note we can't always generate a meaningful
|
|
* icmp message because icmp doesn't have a large enough repertoire
|
|
* of codes and types.
|
|
*
|
|
* If not forwarding, just drop the packet. This could be confusing
|
|
* if ipforwarding was zero but some routing protocol was advancing
|
|
* us as a gateway to somewhere. However, we must let the routing
|
|
* protocol deal with that.
|
|
*
|
|
*/
|
|
|
|
void
|
|
ip6_forward(struct mbuf *m, int srcrt)
|
|
{
|
|
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
|
|
const struct sockaddr_in6 *dst;
|
|
struct rtentry *rt;
|
|
int error = 0, type = 0, code = 0;
|
|
struct mbuf *mcopy = NULL;
|
|
struct ifnet *origifp; /* maybe unnecessary */
|
|
u_int32_t inzone, outzone;
|
|
struct in6_addr src_in6, dst_in6;
|
|
#ifdef FAST_IPSEC
|
|
struct secpolicy *sp = NULL;
|
|
int needipsec = 0;
|
|
int s;
|
|
#endif
|
|
|
|
/*
|
|
* Clear any in-bound checksum flags for this packet.
|
|
*/
|
|
m->m_pkthdr.csum_flags = 0;
|
|
|
|
/*
|
|
* Do not forward packets to multicast destination (should be handled
|
|
* by ip6_mforward().
|
|
* Do not forward packets with unspecified source. It was discussed
|
|
* in July 2000, on ipngwg mailing list.
|
|
*/
|
|
if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
|
|
IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
|
|
IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
|
|
IP6_STATINC(IP6_STAT_CANTFORWARD);
|
|
/* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
|
|
if (ip6_log_time + ip6_log_interval < time_second) {
|
|
ip6_log_time = time_second;
|
|
log(LOG_DEBUG,
|
|
"cannot forward "
|
|
"from %s to %s nxt %d received on %s\n",
|
|
ip6_sprintf(&ip6->ip6_src),
|
|
ip6_sprintf(&ip6->ip6_dst),
|
|
ip6->ip6_nxt,
|
|
if_name(m->m_pkthdr.rcvif));
|
|
}
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
|
|
if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
|
|
/* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
|
|
icmp6_error(m, ICMP6_TIME_EXCEEDED,
|
|
ICMP6_TIME_EXCEED_TRANSIT, 0);
|
|
return;
|
|
}
|
|
ip6->ip6_hlim -= IPV6_HLIMDEC;
|
|
|
|
/*
|
|
* Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
|
|
* size of IPv6 + ICMPv6 headers) bytes of the packet in case
|
|
* we need to generate an ICMP6 message to the src.
|
|
* Thanks to M_EXT, in most cases copy will not occur.
|
|
*
|
|
* It is important to save it before IPsec processing as IPsec
|
|
* processing may modify the mbuf.
|
|
*/
|
|
mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
|
|
|
|
#ifdef FAST_IPSEC
|
|
/* Check the security policy (SP) for the packet */
|
|
|
|
sp = ipsec6_check_policy(m,NULL,0,&needipsec,&error);
|
|
if (error != 0) {
|
|
/*
|
|
* Hack: -EINVAL is used to signal that a packet
|
|
* should be silently discarded. This is typically
|
|
* because we asked key management for an SA and
|
|
* it was delayed (e.g. kicked up to IKE).
|
|
*/
|
|
if (error == -EINVAL)
|
|
error = 0;
|
|
goto freecopy;
|
|
}
|
|
#endif /* FAST_IPSEC */
|
|
|
|
if (srcrt) {
|
|
union {
|
|
struct sockaddr dst;
|
|
struct sockaddr_in6 dst6;
|
|
} u;
|
|
|
|
sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0);
|
|
if ((rt = rtcache_lookup(&ip6_forward_rt, &u.dst)) == NULL) {
|
|
IP6_STATINC(IP6_STAT_NOROUTE);
|
|
/* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */
|
|
if (mcopy) {
|
|
icmp6_error(mcopy, ICMP6_DST_UNREACH,
|
|
ICMP6_DST_UNREACH_NOROUTE, 0);
|
|
}
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
} else if ((rt = rtcache_validate(&ip6_forward_rt)) == NULL &&
|
|
(rt = rtcache_update(&ip6_forward_rt, 1)) == NULL) {
|
|
/*
|
|
* rtcache_getdst(ip6_forward_rt)->sin6_addr was equal to
|
|
* ip6->ip6_dst
|
|
*/
|
|
IP6_STATINC(IP6_STAT_NOROUTE);
|
|
/* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */
|
|
if (mcopy) {
|
|
icmp6_error(mcopy, ICMP6_DST_UNREACH,
|
|
ICMP6_DST_UNREACH_NOROUTE, 0);
|
|
}
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
dst = satocsin6(rtcache_getdst(&ip6_forward_rt));
|
|
|
|
/*
|
|
* Source scope check: if a packet can't be delivered to its
|
|
* destination for the reason that the destination is beyond the scope
|
|
* of the source address, discard the packet and return an icmp6
|
|
* destination unreachable error with Code 2 (beyond scope of source
|
|
* address). We use a local copy of ip6_src, since in6_setscope()
|
|
* will possibly modify its first argument.
|
|
* [draft-ietf-ipngwg-icmp-v3-07, Section 3.1]
|
|
*/
|
|
src_in6 = ip6->ip6_src;
|
|
if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) {
|
|
/* XXX: this should not happen */
|
|
uint64_t *ip6s = IP6_STAT_GETREF();
|
|
ip6s[IP6_STAT_CANTFORWARD]++;
|
|
ip6s[IP6_STAT_BADSCOPE]++;
|
|
IP6_STAT_PUTREF();
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) {
|
|
uint64_t *ip6s = IP6_STAT_GETREF();
|
|
ip6s[IP6_STAT_CANTFORWARD]++;
|
|
ip6s[IP6_STAT_BADSCOPE]++;
|
|
IP6_STAT_PUTREF();
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
if (inzone != outzone) {
|
|
uint64_t *ip6s = IP6_STAT_GETREF();
|
|
ip6s[IP6_STAT_CANTFORWARD]++;
|
|
ip6s[IP6_STAT_BADSCOPE]++;
|
|
IP6_STAT_PUTREF();
|
|
in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
|
|
|
|
if (ip6_log_time + ip6_log_interval < time_second) {
|
|
ip6_log_time = time_second;
|
|
log(LOG_DEBUG,
|
|
"cannot forward "
|
|
"src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
|
|
ip6_sprintf(&ip6->ip6_src),
|
|
ip6_sprintf(&ip6->ip6_dst),
|
|
ip6->ip6_nxt,
|
|
if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
|
|
}
|
|
if (mcopy)
|
|
icmp6_error(mcopy, ICMP6_DST_UNREACH,
|
|
ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
#ifdef FAST_IPSEC
|
|
/*
|
|
* If we need to encapsulate the packet, do it here
|
|
* ipsec6_proces_packet will send the packet using ip6_output
|
|
*/
|
|
if (needipsec) {
|
|
s = splsoftnet();
|
|
error = ipsec6_process_packet(m,sp->req);
|
|
splx(s);
|
|
if (mcopy)
|
|
goto freecopy;
|
|
}
|
|
#endif
|
|
|
|
|
|
|
|
/*
|
|
* Destination scope check: if a packet is going to break the scope
|
|
* zone of packet's destination address, discard it. This case should
|
|
* usually be prevented by appropriately-configured routing table, but
|
|
* we need an explicit check because we may mistakenly forward the
|
|
* packet to a different zone by (e.g.) a default route.
|
|
*/
|
|
dst_in6 = ip6->ip6_dst;
|
|
if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
|
|
in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
|
|
inzone != outzone) {
|
|
uint64_t *ip6s = IP6_STAT_GETREF();
|
|
ip6s[IP6_STAT_CANTFORWARD]++;
|
|
ip6s[IP6_STAT_BADSCOPE]++;
|
|
IP6_STAT_PUTREF();
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
|
|
if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
|
|
in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
|
|
if (mcopy) {
|
|
u_long mtu;
|
|
|
|
mtu = IN6_LINKMTU(rt->rt_ifp);
|
|
icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
|
|
}
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
|
|
if (rt->rt_flags & RTF_GATEWAY)
|
|
dst = (struct sockaddr_in6 *)rt->rt_gateway;
|
|
|
|
/*
|
|
* If we are to forward the packet using the same interface
|
|
* as one we got the packet from, perhaps we should send a redirect
|
|
* to sender to shortcut a hop.
|
|
* Only send redirect if source is sending directly to us,
|
|
* and if packet was not source routed (or has any options).
|
|
* Also, don't send redirect if forwarding using a route
|
|
* modified by a redirect.
|
|
*/
|
|
if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && ip6_sendredirects &&
|
|
(rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
|
|
if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) &&
|
|
nd6_is_addr_neighbor(
|
|
satocsin6(rtcache_getdst(&ip6_forward_rt)),
|
|
rt->rt_ifp)) {
|
|
/*
|
|
* If the incoming interface is equal to the outgoing
|
|
* one, the link attached to the interface is
|
|
* point-to-point, and the IPv6 destination is
|
|
* regarded as on-link on the link, then it will be
|
|
* highly probable that the destination address does
|
|
* not exist on the link and that the packet is going
|
|
* to loop. Thus, we immediately drop the packet and
|
|
* send an ICMPv6 error message.
|
|
* For other routing loops, we dare to let the packet
|
|
* go to the loop, so that a remote diagnosing host
|
|
* can detect the loop by traceroute.
|
|
* type/code is based on suggestion by Rich Draves.
|
|
* not sure if it is the best pick.
|
|
*/
|
|
icmp6_error(mcopy, ICMP6_DST_UNREACH,
|
|
ICMP6_DST_UNREACH_ADDR, 0);
|
|
m_freem(m);
|
|
return;
|
|
}
|
|
type = ND_REDIRECT;
|
|
}
|
|
|
|
/*
|
|
* Fake scoped addresses. Note that even link-local source or
|
|
* destinaion can appear, if the originating node just sends the
|
|
* packet to us (without address resolution for the destination).
|
|
* Since both icmp6_error and icmp6_redirect_output fill the embedded
|
|
* link identifiers, we can do this stuff after making a copy for
|
|
* returning an error.
|
|
*/
|
|
if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
|
|
/*
|
|
* See corresponding comments in ip6_output.
|
|
* XXX: but is it possible that ip6_forward() sends a packet
|
|
* to a loopback interface? I don't think so, and thus
|
|
* I bark here. (jinmei@kame.net)
|
|
* XXX: it is common to route invalid packets to loopback.
|
|
* also, the codepath will be visited on use of ::1 in
|
|
* rthdr. (itojun)
|
|
*/
|
|
#if 1
|
|
if (0)
|
|
#else
|
|
if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
|
|
#endif
|
|
{
|
|
printf("ip6_forward: outgoing interface is loopback. "
|
|
"src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
|
|
ip6_sprintf(&ip6->ip6_src),
|
|
ip6_sprintf(&ip6->ip6_dst),
|
|
ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
|
|
if_name(rt->rt_ifp));
|
|
}
|
|
|
|
/* we can just use rcvif in forwarding. */
|
|
origifp = m->m_pkthdr.rcvif;
|
|
}
|
|
else
|
|
origifp = rt->rt_ifp;
|
|
/*
|
|
* clear embedded scope identifiers if necessary.
|
|
* in6_clearscope will touch the addresses only when necessary.
|
|
*/
|
|
in6_clearscope(&ip6->ip6_src);
|
|
in6_clearscope(&ip6->ip6_dst);
|
|
|
|
#ifdef PFIL_HOOKS
|
|
/*
|
|
* Run through list of hooks for output packets.
|
|
*/
|
|
if ((error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp,
|
|
PFIL_OUT)) != 0)
|
|
goto senderr;
|
|
if (m == NULL)
|
|
goto freecopy;
|
|
ip6 = mtod(m, struct ip6_hdr *);
|
|
#endif /* PFIL_HOOKS */
|
|
|
|
error = nd6_output(rt->rt_ifp, origifp, m, dst, rt);
|
|
if (error) {
|
|
in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
|
|
IP6_STATINC(IP6_STAT_CANTFORWARD);
|
|
} else {
|
|
IP6_STATINC(IP6_STAT_FORWARD);
|
|
in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
|
|
if (type)
|
|
IP6_STATINC(IP6_STAT_REDIRECTSENT);
|
|
else {
|
|
#ifdef GATEWAY
|
|
if (m->m_flags & M_CANFASTFWD)
|
|
ip6flow_create(&ip6_forward_rt, m);
|
|
#endif
|
|
if (mcopy)
|
|
goto freecopy;
|
|
}
|
|
}
|
|
|
|
#ifdef PFIL_HOOKS
|
|
senderr:
|
|
#endif
|
|
if (mcopy == NULL)
|
|
return;
|
|
switch (error) {
|
|
case 0:
|
|
if (type == ND_REDIRECT) {
|
|
icmp6_redirect_output(mcopy, rt);
|
|
return;
|
|
}
|
|
goto freecopy;
|
|
|
|
case EMSGSIZE:
|
|
/* xxx MTU is constant in PPP? */
|
|
goto freecopy;
|
|
|
|
case ENOBUFS:
|
|
/* Tell source to slow down like source quench in IP? */
|
|
goto freecopy;
|
|
|
|
case ENETUNREACH: /* shouldn't happen, checked above */
|
|
case EHOSTUNREACH:
|
|
case ENETDOWN:
|
|
case EHOSTDOWN:
|
|
default:
|
|
type = ICMP6_DST_UNREACH;
|
|
code = ICMP6_DST_UNREACH_ADDR;
|
|
break;
|
|
}
|
|
icmp6_error(mcopy, type, code, 0);
|
|
return;
|
|
|
|
freecopy:
|
|
m_freem(mcopy);
|
|
return;
|
|
}
|