239 lines
6.7 KiB
C
239 lines
6.7 KiB
C
/* $NetBSD: ip6_forward.c,v 1.4 1999/07/30 10:35:36 itojun Exp $ */
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/*
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* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the project nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/domain.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/errno.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <sys/syslog.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_var.h>
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#include <netinet6/ip6.h>
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#if !defined(__FreeBSD__) || __FreeBSD__ < 3
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#include <netinet6/in6_pcb.h>
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#endif
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#include <netinet6/ip6_var.h>
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#include <netinet6/icmp6.h>
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struct route_in6 ip6_forward_rt;
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/*
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* Forward a packet. If some error occurs return the sender
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* an icmp packet. Note we can't always generate a meaningful
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* icmp message because icmp doesn't have a large enough repertoire
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* of codes and types.
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*
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* If not forwarding, just drop the packet. This could be confusing
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* if ipforwarding was zero but some routing protocol was advancing
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* us as a gateway to somewhere. However, we must let the routing
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* protocol deal with that.
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*
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*/
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void
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ip6_forward(m, srcrt)
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struct mbuf *m;
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int srcrt;
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{
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register struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
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register struct sockaddr_in6 *dst;
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register struct rtentry *rt;
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int error, type = 0, code = 0;
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struct mbuf *mcopy;
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if (m->m_flags & (M_BCAST|M_MCAST) ||
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in6_canforward(&ip6->ip6_src, &ip6->ip6_dst) == 0) {
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ip6stat.ip6s_cantforward++;
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ip6stat.ip6s_badscope++;
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#if !defined(__FreeBSD__) || __FreeBSD__ < 3
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if (ip6_log_time + ip6_log_interval < time.tv_sec) {
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ip6_log_time = time.tv_sec;
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#else
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if (ip6_log_time + ip6_log_interval < time_second) {
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ip6_log_time = time_second;
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#endif
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log(LOG_DEBUG,
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"cannot forward "
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"from %s to %s nxt %d received on %s\n",
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ip6_sprintf(&ip6->ip6_src), /* XXX meaningless */
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ip6_sprintf(&ip6->ip6_dst),
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ip6->ip6_nxt,
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m->m_pkthdr.rcvif->if_xname);
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}
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m_freem(m);
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return;
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}
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if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
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icmp6_error(m, ICMP6_TIME_EXCEEDED,
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ICMP6_TIME_EXCEED_TRANSIT, 0);
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return;
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}
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ip6->ip6_hlim -= IPV6_HLIMDEC;
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dst = &ip6_forward_rt.ro_dst;
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if (!srcrt) {
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/*
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* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst
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*/
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if (ip6_forward_rt.ro_rt == 0 ||
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(ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) {
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if (ip6_forward_rt.ro_rt) {
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RTFREE(ip6_forward_rt.ro_rt);
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ip6_forward_rt.ro_rt = 0;
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}
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/* this probably fails but give it a try again */
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#ifdef __NetBSD__
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rtalloc((struct route *)&ip6_forward_rt);
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#else
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rtalloc_ign((struct route *)&ip6_forward_rt,
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RTF_PRCLONING);
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#endif
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}
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if (ip6_forward_rt.ro_rt == 0) {
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ip6stat.ip6s_noroute++;
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icmp6_error(m, ICMP6_DST_UNREACH,
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ICMP6_DST_UNREACH_NOROUTE, 0);
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return;
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}
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} else if ((rt = ip6_forward_rt.ro_rt) == 0 ||
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!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) {
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if (ip6_forward_rt.ro_rt) {
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RTFREE(ip6_forward_rt.ro_rt);
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ip6_forward_rt.ro_rt = 0;
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}
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bzero(dst, sizeof(*dst));
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dst->sin6_len = sizeof(struct sockaddr_in6);
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dst->sin6_family = AF_INET6;
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dst->sin6_addr = ip6->ip6_dst;
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#ifdef __NetBSD__
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rtalloc((struct route *)&ip6_forward_rt);
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#else
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rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING);
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#endif
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if (ip6_forward_rt.ro_rt == 0) {
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ip6stat.ip6s_noroute++;
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icmp6_error(m, ICMP6_DST_UNREACH,
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ICMP6_DST_UNREACH_NOROUTE, 0);
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return;
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}
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}
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rt = ip6_forward_rt.ro_rt;
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if (m->m_pkthdr.len > rt->rt_ifp->if_mtu){
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icmp6_error(m, ICMP6_PACKET_TOO_BIG, 0, rt->rt_ifp->if_mtu);
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return;
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}
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if (rt->rt_flags & RTF_GATEWAY)
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dst = (struct sockaddr_in6 *)rt->rt_gateway;
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/*
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* Save at most 528 bytes of the packet in case
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* we need to generate an ICMP6 message to the src.
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* Thanks to M_EXT, in most cases copy will not occur.
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*/
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mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
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/*
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* If we are to forward the packet using the same interface
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* as one we got the packet from, perhaps we should send a redirect
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* to sender to shortcut a hop.
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* Only send redirect if source is sending directly to us,
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* and if packet was not source routed (or has any options).
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* Also, don't send redirect if forwarding using a route
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* modified by a redirect.
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*/
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if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
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(rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0)
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type = ND_REDIRECT;
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error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m,
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(struct sockaddr *)dst,
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ip6_forward_rt.ro_rt);
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if (error)
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ip6stat.ip6s_cantforward++;
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else {
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ip6stat.ip6s_forward++;
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if (type)
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ip6stat.ip6s_redirectsent++;
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else {
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if (mcopy)
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goto freecopy;
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}
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}
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if (mcopy == NULL)
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return;
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switch (error) {
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case 0:
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#if 1
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if (type == ND_REDIRECT) {
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icmp6_redirect_output(mcopy, rt);
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return;
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}
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#endif
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goto freecopy;
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case EMSGSIZE:
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/* xxx MTU is constant in PPP? */
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goto freecopy;
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case ENOBUFS:
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/* Tell source to slow down like source quench in IP? */
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goto freecopy;
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case ENETUNREACH: /* shouldn't happen, checked above */
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case EHOSTUNREACH:
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case ENETDOWN:
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case EHOSTDOWN:
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default:
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type = ICMP6_DST_UNREACH;
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code = ICMP6_DST_UNREACH_ADDR;
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break;
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}
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icmp6_error(mcopy, type, code, 0);
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return;
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freecopy:
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m_freem(mcopy);
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}
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