f9656ee690
is too big for the outgoing interface and no firewall is involed. This problem was introduced in https://svnweb.freebsd.org/changeset/base/324996 Thanks to Irene Ruengeler for finding the bug and testing the fix. Reviewed by: kp@ MFC after: 3 days
306 lines
8.2 KiB
C
306 lines
8.2 KiB
C
/*-
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* Copyright (c) 2014-2016 Andrey V. Elsukov <ae@FreeBSD.org>
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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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*
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet6.h"
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#include "opt_ipstealth.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/route.h>
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#include <net/pfil.h>
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#include <net/vnet.h>
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#include <netinet/in.h>
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#include <netinet/in_kdtrace.h>
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#include <netinet/in_var.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip6.h>
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#include <netinet/icmp6.h>
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#include <netinet6/in6_var.h>
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#include <netinet6/in6_fib.h>
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#include <netinet6/ip6_var.h>
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#include <netinet6/nd6.h>
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static int
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ip6_findroute(struct nhop6_basic *pnh, const struct sockaddr_in6 *dst,
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struct mbuf *m)
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{
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if (fib6_lookup_nh_basic(M_GETFIB(m), &dst->sin6_addr,
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dst->sin6_scope_id, 0, dst->sin6_flowinfo, pnh) != 0) {
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IP6STAT_INC(ip6s_noroute);
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IP6STAT_INC(ip6s_cantforward);
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icmp6_error(m, ICMP6_DST_UNREACH,
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ICMP6_DST_UNREACH_NOROUTE, 0);
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return (EHOSTUNREACH);
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}
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if (pnh->nh_flags & NHF_BLACKHOLE) {
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IP6STAT_INC(ip6s_cantforward);
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m_freem(m);
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return (EHOSTUNREACH);
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}
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if (pnh->nh_flags & NHF_REJECT) {
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IP6STAT_INC(ip6s_cantforward);
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icmp6_error(m, ICMP6_DST_UNREACH,
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ICMP6_DST_UNREACH_REJECT, 0);
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return (EHOSTUNREACH);
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}
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return (0);
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}
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struct mbuf*
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ip6_tryforward(struct mbuf *m)
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{
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struct sockaddr_in6 dst;
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struct nhop6_basic nh;
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struct m_tag *fwd_tag;
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struct ip6_hdr *ip6;
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struct ifnet *rcvif;
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uint32_t plen;
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int error;
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/*
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* Fallback conditions to ip6_input for slow path processing.
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*/
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ip6 = mtod(m, struct ip6_hdr *);
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if ((m->m_flags & (M_BCAST | M_MCAST)) != 0 ||
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ip6->ip6_nxt == IPPROTO_HOPOPTS ||
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IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
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IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst) ||
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IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src) ||
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IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) ||
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in6_localip(&ip6->ip6_dst))
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return (m);
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/*
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* Check that the amount of data in the buffers
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* is as at least much as the IPv6 header would have us expect.
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* Trim mbufs if longer than we expect.
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* Drop packet if shorter than we expect.
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*/
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rcvif = m->m_pkthdr.rcvif;
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plen = ntohs(ip6->ip6_plen);
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if (plen == 0) {
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/*
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* Jumbograms must have hop-by-hop header and go via
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* slow path.
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*/
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IP6STAT_INC(ip6s_badoptions);
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goto dropin;
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}
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if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
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IP6STAT_INC(ip6s_tooshort);
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in6_ifstat_inc(rcvif, ifs6_in_truncated);
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goto dropin;
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}
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if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
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if (m->m_len == m->m_pkthdr.len) {
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m->m_len = sizeof(struct ip6_hdr) + plen;
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m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
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} else
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m_adj(m, sizeof(struct ip6_hdr) + plen -
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m->m_pkthdr.len);
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}
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/*
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* Hop limit.
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*/
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#ifdef IPSTEALTH
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if (!V_ip6stealth)
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#endif
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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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m = NULL;
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goto dropin;
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}
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bzero(&dst, sizeof(dst));
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dst.sin6_family = AF_INET6;
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dst.sin6_len = sizeof(dst);
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dst.sin6_addr = ip6->ip6_dst;
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/*
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* Incoming packet firewall processing.
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*/
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if (!PFIL_HOOKED(&V_inet6_pfil_hook))
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goto passin;
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if (pfil_run_hooks(&V_inet6_pfil_hook, &m, rcvif, PFIL_IN, 0,
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NULL) != 0 || m == NULL)
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goto dropin;
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/*
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* If packet filter sets the M_FASTFWD_OURS flag, this means
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* that new destination or next hop is our local address.
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* So, we can just go back to ip6_input.
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* XXX: should we decrement ip6_hlim in such case?
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*
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* Also it can forward packet to another destination, e.g.
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* M_IP6_NEXTHOP flag is set and fwd_tag is attached to mbuf.
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*/
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if (m->m_flags & M_FASTFWD_OURS)
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return (m);
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ip6 = mtod(m, struct ip6_hdr *);
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if ((m->m_flags & M_IP6_NEXTHOP) &&
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(fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
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/*
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* Now we will find route to forwarded by pfil destination.
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*/
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bcopy((fwd_tag + 1), &dst, sizeof(dst));
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m->m_flags &= ~M_IP6_NEXTHOP;
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m_tag_delete(m, fwd_tag);
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} else {
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/* Update dst since pfil could change it */
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dst.sin6_addr = ip6->ip6_dst;
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}
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passin:
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/*
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* Find route to destination.
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*/
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if (ip6_findroute(&nh, &dst, m) != 0) {
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m = NULL;
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in6_ifstat_inc(rcvif, ifs6_in_noroute);
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goto dropin;
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}
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if (!PFIL_HOOKED(&V_inet6_pfil_hook)) {
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if (m->m_pkthdr.len > nh.nh_mtu) {
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in6_ifstat_inc(nh.nh_ifp, ifs6_in_toobig);
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icmp6_error(m, ICMP6_PACKET_TOO_BIG, 0, nh.nh_mtu);
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m = NULL;
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goto dropout;
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}
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goto passout;
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}
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/*
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* Outgoing packet firewall processing.
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*/
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if (pfil_run_hooks(&V_inet6_pfil_hook, &m, nh.nh_ifp, PFIL_OUT,
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PFIL_FWD, NULL) != 0 || m == NULL)
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goto dropout;
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/*
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* We used slow path processing for packets with scoped addresses.
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* So, scope checks aren't needed here.
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*/
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if (m->m_pkthdr.len > nh.nh_mtu) {
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in6_ifstat_inc(nh.nh_ifp, ifs6_in_toobig);
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icmp6_error(m, ICMP6_PACKET_TOO_BIG, 0, nh.nh_mtu);
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m = NULL;
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goto dropout;
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}
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/*
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* If packet filter sets the M_FASTFWD_OURS flag, this means
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* that new destination or next hop is our local address.
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* So, we can just go back to ip6_input.
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*
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* Also it can forward packet to another destination, e.g.
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* M_IP6_NEXTHOP flag is set and fwd_tag is attached to mbuf.
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*/
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if (m->m_flags & M_FASTFWD_OURS) {
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/*
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* XXX: we did one hop and should decrement hop limit. But
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* now we are the destination and just don't pay attention.
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*/
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return (m);
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}
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/*
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* Again. A packet filter could change the destination address.
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*/
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ip6 = mtod(m, struct ip6_hdr *);
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if (m->m_flags & M_IP6_NEXTHOP)
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fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
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else
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fwd_tag = NULL;
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if (fwd_tag != NULL ||
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!IN6_ARE_ADDR_EQUAL(&dst.sin6_addr, &ip6->ip6_dst)) {
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if (fwd_tag != NULL) {
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bcopy((fwd_tag + 1), &dst, sizeof(dst));
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m->m_flags &= ~M_IP6_NEXTHOP;
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m_tag_delete(m, fwd_tag);
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} else
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dst.sin6_addr = ip6->ip6_dst;
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/*
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* Redo route lookup with new destination address
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*/
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if (ip6_findroute(&nh, &dst, m) != 0) {
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m = NULL;
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goto dropout;
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}
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}
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passout:
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#ifdef IPSTEALTH
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if (!V_ip6stealth)
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#endif
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{
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ip6->ip6_hlim -= IPV6_HLIMDEC;
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}
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m_clrprotoflags(m); /* Avoid confusing lower layers. */
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IP_PROBE(send, NULL, NULL, ip6, nh.nh_ifp, NULL, ip6);
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/*
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* XXX: we need to use destination address with embedded scope
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* zone id, because LLTABLE uses such form of addresses for lookup.
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*/
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dst.sin6_addr = nh.nh_addr;
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if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6_addr))
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dst.sin6_addr.s6_addr16[1] = htons(nh.nh_ifp->if_index & 0xffff);
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error = (*nh.nh_ifp->if_output)(nh.nh_ifp, m,
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(struct sockaddr *)&dst, NULL);
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if (error != 0) {
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in6_ifstat_inc(nh.nh_ifp, ifs6_out_discard);
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IP6STAT_INC(ip6s_cantforward);
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} else {
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in6_ifstat_inc(nh.nh_ifp, ifs6_out_forward);
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IP6STAT_INC(ip6s_forward);
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}
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return (NULL);
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dropin:
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in6_ifstat_inc(rcvif, ifs6_in_discard);
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goto drop;
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dropout:
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in6_ifstat_inc(nh.nh_ifp, ifs6_out_discard);
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drop:
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if (m != NULL)
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m_freem(m);
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return (NULL);
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}
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