ip6_forward.c revision 120913
162587Sitojun/* $FreeBSD: head/sys/netinet6/ip6_forward.c 120913 2003-10-08 18:26:08Z ume $ */ 278064Sume/* $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $ */ 362587Sitojun 453541Sshin/* 553541Sshin * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 653541Sshin * All rights reserved. 753541Sshin * 853541Sshin * Redistribution and use in source and binary forms, with or without 953541Sshin * modification, are permitted provided that the following conditions 1053541Sshin * are met: 1153541Sshin * 1. Redistributions of source code must retain the above copyright 1253541Sshin * notice, this list of conditions and the following disclaimer. 1353541Sshin * 2. Redistributions in binary form must reproduce the above copyright 1453541Sshin * notice, this list of conditions and the following disclaimer in the 1553541Sshin * documentation and/or other materials provided with the distribution. 1653541Sshin * 3. Neither the name of the project nor the names of its contributors 1753541Sshin * may be used to endorse or promote products derived from this software 1853541Sshin * without specific prior written permission. 1953541Sshin * 2053541Sshin * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 2153541Sshin * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2253541Sshin * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2353541Sshin * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 2453541Sshin * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2553541Sshin * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2653541Sshin * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2753541Sshin * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2853541Sshin * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2953541Sshin * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3053541Sshin * SUCH DAMAGE. 3153541Sshin */ 3253541Sshin 3362587Sitojun#include "opt_ip6fw.h" 3462587Sitojun#include "opt_inet.h" 3562587Sitojun#include "opt_inet6.h" 3655009Sshin#include "opt_ipsec.h" 37120386Ssam#include "opt_pfil_hooks.h" 3853541Sshin 3953541Sshin#include <sys/param.h> 4053541Sshin#include <sys/systm.h> 4178064Sume#include <sys/malloc.h> 4253541Sshin#include <sys/mbuf.h> 4353541Sshin#include <sys/domain.h> 4453541Sshin#include <sys/protosw.h> 4553541Sshin#include <sys/socket.h> 4653541Sshin#include <sys/errno.h> 4753541Sshin#include <sys/time.h> 4878064Sume#include <sys/kernel.h> 4953541Sshin#include <sys/syslog.h> 5053541Sshin 5153541Sshin#include <net/if.h> 5253541Sshin#include <net/route.h> 5384994Sdarrenr#ifdef PFIL_HOOKS 5484994Sdarrenr#include <net/pfil.h> 5584994Sdarrenr#endif 5653541Sshin 5753541Sshin#include <netinet/in.h> 5853541Sshin#include <netinet/in_var.h> 5978064Sume#include <netinet/in_systm.h> 6078064Sume#include <netinet/ip.h> 6162587Sitojun#include <netinet/ip_var.h> 6278064Sume#include <netinet6/in6_var.h> 6362587Sitojun#include <netinet/ip6.h> 6453541Sshin#include <netinet6/ip6_var.h> 6562587Sitojun#include <netinet/icmp6.h> 6653541Sshin#include <netinet6/nd6.h> 6753541Sshin 6878064Sume#include <netinet/in_pcb.h> 6978064Sume 7063256Sitojun#ifdef IPSEC 7153541Sshin#include <netinet6/ipsec.h> 7278064Sume#ifdef INET6 7362601Sitojun#include <netinet6/ipsec6.h> 7478064Sume#endif 7553541Sshin#include <netkey/key.h> 7663256Sitojun#endif /* IPSEC */ 7753541Sshin 78105199Ssam#ifdef FAST_IPSEC 79105199Ssam#include <netipsec/ipsec.h> 80105199Ssam#include <netipsec/ipsec6.h> 81105199Ssam#include <netipsec/key.h> 82105199Ssam#define IPSEC 83105199Ssam#endif /* FAST_IPSEC */ 84105199Ssam 8553541Sshin#include <netinet6/ip6_fw.h> 8653541Sshin 8753541Sshin#include <net/net_osdep.h> 8853541Sshin 8984994Sdarrenr#include <netinet6/ip6protosw.h> 9084994Sdarrenr 9153541Sshinstruct route_in6 ip6_forward_rt; 9253541Sshin 9353541Sshin/* 9453541Sshin * Forward a packet. If some error occurs return the sender 9553541Sshin * an icmp packet. Note we can't always generate a meaningful 9653541Sshin * icmp message because icmp doesn't have a large enough repertoire 9753541Sshin * of codes and types. 9853541Sshin * 9953541Sshin * If not forwarding, just drop the packet. This could be confusing 10053541Sshin * if ipforwarding was zero but some routing protocol was advancing 10153541Sshin * us as a gateway to somewhere. However, we must let the routing 10253541Sshin * protocol deal with that. 10353541Sshin * 10453541Sshin */ 10553541Sshin 10653541Sshinvoid 10753541Sshinip6_forward(m, srcrt) 10853541Sshin struct mbuf *m; 10953541Sshin int srcrt; 11053541Sshin{ 11153541Sshin struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 11278064Sume struct sockaddr_in6 *dst; 11378064Sume struct rtentry *rt; 11453541Sshin int error, type = 0, code = 0; 11562587Sitojun struct mbuf *mcopy = NULL; 11662587Sitojun struct ifnet *origifp; /* maybe unnecessary */ 11763256Sitojun#ifdef IPSEC 11853541Sshin struct secpolicy *sp = NULL; 11953541Sshin#endif 12053541Sshin 12163256Sitojun#ifdef IPSEC 12253541Sshin /* 12353541Sshin * Check AH/ESP integrity. 12453541Sshin */ 12553541Sshin /* 12653541Sshin * Don't increment ip6s_cantforward because this is the check 12753541Sshin * before forwarding packet actually. 12853541Sshin */ 12953541Sshin if (ipsec6_in_reject(m, NULL)) { 130105199Ssam#if !defined(FAST_IPSEC) 13153541Sshin ipsec6stat.in_polvio++; 132105199Ssam#endif 13353541Sshin m_freem(m); 13453541Sshin return; 13553541Sshin } 13695023Ssuz#endif /* IPSEC */ 13753541Sshin 13878064Sume /* 13978064Sume * Do not forward packets to multicast destination (should be handled 14078064Sume * by ip6_mforward(). 14178064Sume * Do not forward packets with unspecified source. It was discussed 142120913Sume * in July 2000, on the ipngwg mailing list. 14378064Sume */ 14462587Sitojun if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 14578064Sume IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 14678064Sume IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 14753541Sshin ip6stat.ip6s_cantforward++; 14853541Sshin /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 14953541Sshin if (ip6_log_time + ip6_log_interval < time_second) { 15053541Sshin ip6_log_time = time_second; 15153541Sshin log(LOG_DEBUG, 15253541Sshin "cannot forward " 15353541Sshin "from %s to %s nxt %d received on %s\n", 15462587Sitojun ip6_sprintf(&ip6->ip6_src), 15562587Sitojun ip6_sprintf(&ip6->ip6_dst), 15653541Sshin ip6->ip6_nxt, 15753541Sshin if_name(m->m_pkthdr.rcvif)); 15853541Sshin } 15953541Sshin m_freem(m); 16053541Sshin return; 16153541Sshin } 16253541Sshin 16353541Sshin if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 16453541Sshin /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 16553541Sshin icmp6_error(m, ICMP6_TIME_EXCEEDED, 16653541Sshin ICMP6_TIME_EXCEED_TRANSIT, 0); 16753541Sshin return; 16853541Sshin } 16953541Sshin ip6->ip6_hlim -= IPV6_HLIMDEC; 17053541Sshin 17162587Sitojun /* 17262587Sitojun * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 17362587Sitojun * size of IPv6 + ICMPv6 headers) bytes of the packet in case 17462587Sitojun * we need to generate an ICMP6 message to the src. 17562587Sitojun * Thanks to M_EXT, in most cases copy will not occur. 17662587Sitojun * 17762587Sitojun * It is important to save it before IPsec processing as IPsec 17862587Sitojun * processing may modify the mbuf. 17962587Sitojun */ 18062587Sitojun mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 18162587Sitojun 18263256Sitojun#ifdef IPSEC 18353541Sshin /* get a security policy for this packet */ 184120913Sume sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 185120913Sume IP_FORWARDING, &error); 18653541Sshin if (sp == NULL) { 18753541Sshin ipsec6stat.out_inval++; 18853541Sshin ip6stat.ip6s_cantforward++; 18962587Sitojun if (mcopy) { 19062587Sitojun#if 0 19162587Sitojun /* XXX: what icmp ? */ 19262587Sitojun#else 19362587Sitojun m_freem(mcopy); 19462587Sitojun#endif 19562587Sitojun } 19653541Sshin m_freem(m); 19753541Sshin return; 19853541Sshin } 19953541Sshin 20053541Sshin error = 0; 20153541Sshin 20253541Sshin /* check policy */ 20353541Sshin switch (sp->policy) { 20453541Sshin case IPSEC_POLICY_DISCARD: 20553541Sshin /* 20653541Sshin * This packet is just discarded. 20753541Sshin */ 20853541Sshin ipsec6stat.out_polvio++; 20953541Sshin ip6stat.ip6s_cantforward++; 21053541Sshin key_freesp(sp); 21162587Sitojun if (mcopy) { 21262587Sitojun#if 0 21362587Sitojun /* XXX: what icmp ? */ 21462587Sitojun#else 21562587Sitojun m_freem(mcopy); 21662587Sitojun#endif 21762587Sitojun } 21853541Sshin m_freem(m); 21953541Sshin return; 22053541Sshin 22153541Sshin case IPSEC_POLICY_BYPASS: 22253541Sshin case IPSEC_POLICY_NONE: 22353541Sshin /* no need to do IPsec. */ 22453541Sshin key_freesp(sp); 22553541Sshin goto skip_ipsec; 22662587Sitojun 22753541Sshin case IPSEC_POLICY_IPSEC: 22853541Sshin if (sp->req == NULL) { 22953541Sshin /* XXX should be panic ? */ 23053541Sshin printf("ip6_forward: No IPsec request specified.\n"); 23153541Sshin ip6stat.ip6s_cantforward++; 23253541Sshin key_freesp(sp); 23362587Sitojun if (mcopy) { 23462587Sitojun#if 0 23562587Sitojun /* XXX: what icmp ? */ 23662587Sitojun#else 23762587Sitojun m_freem(mcopy); 23862587Sitojun#endif 23962587Sitojun } 24053541Sshin m_freem(m); 24153541Sshin return; 24253541Sshin } 24353541Sshin /* do IPsec */ 24453541Sshin break; 24553541Sshin 24653541Sshin case IPSEC_POLICY_ENTRUST: 24753541Sshin default: 24853541Sshin /* should be panic ?? */ 24953541Sshin printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 25053541Sshin key_freesp(sp); 25153541Sshin goto skip_ipsec; 25253541Sshin } 25353541Sshin 25453541Sshin { 25553541Sshin struct ipsec_output_state state; 25653541Sshin 25753541Sshin /* 25853541Sshin * All the extension headers will become inaccessible 25953541Sshin * (since they can be encrypted). 26053541Sshin * Don't panic, we need no more updates to extension headers 26153541Sshin * on inner IPv6 packet (since they are now encapsulated). 26253541Sshin * 26353541Sshin * IPv6 [ESP|AH] IPv6 [extension headers] payload 26453541Sshin */ 26553541Sshin bzero(&state, sizeof(state)); 26653541Sshin state.m = m; 26753541Sshin state.ro = NULL; /* update at ipsec6_output_tunnel() */ 26853541Sshin state.dst = NULL; /* update at ipsec6_output_tunnel() */ 26953541Sshin 27053541Sshin error = ipsec6_output_tunnel(&state, sp, 0); 27153541Sshin 27253541Sshin m = state.m; 27353541Sshin key_freesp(sp); 27453541Sshin 27553541Sshin if (error) { 27653541Sshin /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 27753541Sshin switch (error) { 27853541Sshin case EHOSTUNREACH: 27953541Sshin case ENETUNREACH: 28053541Sshin case EMSGSIZE: 28153541Sshin case ENOBUFS: 28253541Sshin case ENOMEM: 28353541Sshin break; 28453541Sshin default: 28553541Sshin printf("ip6_output (ipsec): error code %d\n", error); 286120913Sume /* FALLTHROUGH */ 28753541Sshin case ENOENT: 28853541Sshin /* don't show these error codes to the user */ 28953541Sshin break; 29053541Sshin } 29153541Sshin ip6stat.ip6s_cantforward++; 29262587Sitojun if (mcopy) { 29362587Sitojun#if 0 29462587Sitojun /* XXX: what icmp ? */ 29562587Sitojun#else 29662587Sitojun m_freem(mcopy); 29762587Sitojun#endif 29862587Sitojun } 29953541Sshin m_freem(m); 30053541Sshin return; 30153541Sshin } 30253541Sshin } 30353541Sshin skip_ipsec: 30463256Sitojun#endif /* IPSEC */ 30553541Sshin 30678064Sume dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst; 30753541Sshin if (!srcrt) { 308120913Sume /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */ 30953541Sshin if (ip6_forward_rt.ro_rt == 0 || 31053541Sshin (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) { 31153541Sshin if (ip6_forward_rt.ro_rt) { 31253541Sshin RTFREE(ip6_forward_rt.ro_rt); 31353541Sshin ip6_forward_rt.ro_rt = 0; 31453541Sshin } 315120913Sume 31653541Sshin /* this probably fails but give it a try again */ 31753541Sshin rtalloc_ign((struct route *)&ip6_forward_rt, 31853541Sshin RTF_PRCLONING); 31953541Sshin } 32062587Sitojun 32153541Sshin if (ip6_forward_rt.ro_rt == 0) { 32253541Sshin ip6stat.ip6s_noroute++; 32378064Sume in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 32462587Sitojun if (mcopy) { 32562587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 32662587Sitojun ICMP6_DST_UNREACH_NOROUTE, 0); 32762587Sitojun } 32862587Sitojun m_freem(m); 32953541Sshin return; 33053541Sshin } 33153541Sshin } else if ((rt = ip6_forward_rt.ro_rt) == 0 || 332120913Sume !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 33353541Sshin if (ip6_forward_rt.ro_rt) { 33453541Sshin RTFREE(ip6_forward_rt.ro_rt); 33553541Sshin ip6_forward_rt.ro_rt = 0; 33653541Sshin } 33753541Sshin bzero(dst, sizeof(*dst)); 33853541Sshin dst->sin6_len = sizeof(struct sockaddr_in6); 33953541Sshin dst->sin6_family = AF_INET6; 34053541Sshin dst->sin6_addr = ip6->ip6_dst; 34153541Sshin 34253541Sshin rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING); 34353541Sshin if (ip6_forward_rt.ro_rt == 0) { 34453541Sshin ip6stat.ip6s_noroute++; 34578064Sume in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 34662587Sitojun if (mcopy) { 34762587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 34862587Sitojun ICMP6_DST_UNREACH_NOROUTE, 0); 34962587Sitojun } 35062587Sitojun m_freem(m); 35153541Sshin return; 35253541Sshin } 35353541Sshin } 35453541Sshin rt = ip6_forward_rt.ro_rt; 35562587Sitojun 35662587Sitojun /* 35762587Sitojun * Scope check: if a packet can't be delivered to its destination 35862587Sitojun * for the reason that the destination is beyond the scope of the 35962587Sitojun * source address, discard the packet and return an icmp6 destination 36062587Sitojun * unreachable error with Code 2 (beyond scope of source address). 36195023Ssuz * [draft-ietf-ipngwg-icmp-v3-02.txt, Section 3.1] 36262587Sitojun */ 36362587Sitojun if (in6_addr2scopeid(m->m_pkthdr.rcvif, &ip6->ip6_src) != 36462587Sitojun in6_addr2scopeid(rt->rt_ifp, &ip6->ip6_src)) { 36562587Sitojun ip6stat.ip6s_cantforward++; 36662587Sitojun ip6stat.ip6s_badscope++; 36762587Sitojun in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 36862587Sitojun 36962587Sitojun if (ip6_log_time + ip6_log_interval < time_second) { 37062587Sitojun ip6_log_time = time_second; 37162587Sitojun log(LOG_DEBUG, 37262587Sitojun "cannot forward " 37362587Sitojun "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 37462587Sitojun ip6_sprintf(&ip6->ip6_src), 37562587Sitojun ip6_sprintf(&ip6->ip6_dst), 37662587Sitojun ip6->ip6_nxt, 37762587Sitojun if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 37862587Sitojun } 37962587Sitojun if (mcopy) 38062587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 38162587Sitojun ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 38262587Sitojun m_freem(m); 38362587Sitojun return; 38462587Sitojun } 38562587Sitojun 38662587Sitojun if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { 38753541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 38862587Sitojun if (mcopy) { 38962587Sitojun u_long mtu; 39063256Sitojun#ifdef IPSEC 39162587Sitojun struct secpolicy *sp; 39262587Sitojun int ipsecerror; 39362587Sitojun size_t ipsechdrsiz; 39462587Sitojun#endif 39562587Sitojun 39662587Sitojun mtu = rt->rt_ifp->if_mtu; 39763256Sitojun#ifdef IPSEC 39862587Sitojun /* 39962587Sitojun * When we do IPsec tunnel ingress, we need to play 40062587Sitojun * with if_mtu value (decrement IPsec header size 40162587Sitojun * from mtu value). The code is much simpler than v4 40262587Sitojun * case, as we have the outgoing interface for 40362587Sitojun * encapsulated packet as "rt->rt_ifp". 40462587Sitojun */ 40562587Sitojun sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 40662587Sitojun IP_FORWARDING, &ipsecerror); 40762587Sitojun if (sp) { 40862587Sitojun ipsechdrsiz = ipsec6_hdrsiz(mcopy, 40962587Sitojun IPSEC_DIR_OUTBOUND, NULL); 41062587Sitojun if (ipsechdrsiz < mtu) 41162587Sitojun mtu -= ipsechdrsiz; 41262587Sitojun } 41362587Sitojun 41462587Sitojun /* 41562587Sitojun * if mtu becomes less than minimum MTU, 41662587Sitojun * tell minimum MTU (and I'll need to fragment it). 41762587Sitojun */ 41862587Sitojun if (mtu < IPV6_MMTU) 41962587Sitojun mtu = IPV6_MMTU; 42062587Sitojun#endif 42162587Sitojun icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 42262587Sitojun } 42362587Sitojun m_freem(m); 42453541Sshin return; 425120913Sume } 42653541Sshin 42753541Sshin if (rt->rt_flags & RTF_GATEWAY) 42853541Sshin dst = (struct sockaddr_in6 *)rt->rt_gateway; 42953541Sshin 43053541Sshin /* 43153541Sshin * If we are to forward the packet using the same interface 43253541Sshin * as one we got the packet from, perhaps we should send a redirect 43353541Sshin * to sender to shortcut a hop. 43453541Sshin * Only send redirect if source is sending directly to us, 43553541Sshin * and if packet was not source routed (or has any options). 43653541Sshin * Also, don't send redirect if forwarding using a route 43753541Sshin * modified by a redirect. 43853541Sshin */ 43953541Sshin if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 44078064Sume (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 44178064Sume if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 44278064Sume /* 44378064Sume * If the incoming interface is equal to the outgoing 44478064Sume * one, and the link attached to the interface is 44578064Sume * point-to-point, then it will be highly probable 44678064Sume * that a routing loop occurs. Thus, we immediately 44778064Sume * drop the packet and send an ICMPv6 error message. 44878064Sume * 44978064Sume * type/code is based on suggestion by Rich Draves. 45078064Sume * not sure if it is the best pick. 45178064Sume */ 45278064Sume icmp6_error(mcopy, ICMP6_DST_UNREACH, 45378064Sume ICMP6_DST_UNREACH_ADDR, 0); 45478064Sume m_freem(m); 45578064Sume return; 45678064Sume } 45753541Sshin type = ND_REDIRECT; 45878064Sume } 45953541Sshin 46053541Sshin /* 46153541Sshin * Check with the firewall... 46253541Sshin */ 46366303Sume if (ip6_fw_enable && ip6_fw_chk_ptr) { 46453541Sshin u_short port = 0; 46553541Sshin /* If ipfw says divert, we have to just drop packet */ 46653541Sshin if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) { 46753541Sshin m_freem(m); 46853541Sshin goto freecopy; 46953541Sshin } 47053541Sshin if (!m) 47153541Sshin goto freecopy; 47253541Sshin } 47353541Sshin 47462587Sitojun /* 47562587Sitojun * Fake scoped addresses. Note that even link-local source or 47662587Sitojun * destinaion can appear, if the originating node just sends the 47762587Sitojun * packet to us (without address resolution for the destination). 47862587Sitojun * Since both icmp6_error and icmp6_redirect_output fill the embedded 47978064Sume * link identifiers, we can do this stuff after making a copy for 48078064Sume * returning an error. 48162587Sitojun */ 48262587Sitojun if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 48362587Sitojun /* 48462587Sitojun * See corresponding comments in ip6_output. 48562587Sitojun * XXX: but is it possible that ip6_forward() sends a packet 48662587Sitojun * to a loopback interface? I don't think so, and thus 48762587Sitojun * I bark here. (jinmei@kame.net) 48862587Sitojun * XXX: it is common to route invalid packets to loopback. 48962587Sitojun * also, the codepath will be visited on use of ::1 in 49062587Sitojun * rthdr. (itojun) 49162587Sitojun */ 49262587Sitojun#if 1 49362587Sitojun if (0) 49462587Sitojun#else 49562587Sitojun if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 49662587Sitojun#endif 49762587Sitojun { 49862587Sitojun printf("ip6_forward: outgoing interface is loopback. " 499120913Sume "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 500120913Sume ip6_sprintf(&ip6->ip6_src), 501120913Sume ip6_sprintf(&ip6->ip6_dst), 502120913Sume ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 503120913Sume if_name(rt->rt_ifp)); 50462587Sitojun } 50562587Sitojun 50678064Sume /* we can just use rcvif in forwarding. */ 50778064Sume origifp = m->m_pkthdr.rcvif; 50862587Sitojun } 50962587Sitojun else 51062587Sitojun origifp = rt->rt_ifp; 51178064Sume#ifndef SCOPEDROUTING 51278064Sume /* 51378064Sume * clear embedded scope identifiers if necessary. 51478064Sume * in6_clearscope will touch the addresses only when necessary. 51578064Sume */ 51678064Sume in6_clearscope(&ip6->ip6_src); 51778064Sume in6_clearscope(&ip6->ip6_dst); 51862587Sitojun#endif 51962587Sitojun 52084994Sdarrenr#ifdef PFIL_HOOKS 52184994Sdarrenr /* 52284994Sdarrenr * Run through list of hooks for output packets. 52384994Sdarrenr */ 524120593Ssam error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT); 525120593Ssam if (error != 0) 526120593Ssam goto senderr; 527120386Ssam if (m == NULL) 528120386Ssam goto freecopy; 529120386Ssam ip6 = mtod(m, struct ip6_hdr *); 53084994Sdarrenr#endif /* PFIL_HOOKS */ 53184994Sdarrenr 53262587Sitojun error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 53353541Sshin if (error) { 53453541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 53553541Sshin ip6stat.ip6s_cantforward++; 53653541Sshin } else { 53753541Sshin ip6stat.ip6s_forward++; 53853541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 53953541Sshin if (type) 54053541Sshin ip6stat.ip6s_redirectsent++; 54153541Sshin else { 54253541Sshin if (mcopy) 54353541Sshin goto freecopy; 54453541Sshin } 54553541Sshin } 546120913Sume 547120593Ssam#ifdef PFIL_HOOKS 548120593Ssamsenderr: 549120593Ssam#endif 55053541Sshin if (mcopy == NULL) 55153541Sshin return; 55253541Sshin switch (error) { 55353541Sshin case 0: 55453541Sshin if (type == ND_REDIRECT) { 55553541Sshin icmp6_redirect_output(mcopy, rt); 55653541Sshin return; 55753541Sshin } 55853541Sshin goto freecopy; 55953541Sshin 56053541Sshin case EMSGSIZE: 56153541Sshin /* xxx MTU is constant in PPP? */ 56253541Sshin goto freecopy; 56353541Sshin 56453541Sshin case ENOBUFS: 56553541Sshin /* Tell source to slow down like source quench in IP? */ 56653541Sshin goto freecopy; 56753541Sshin 56853541Sshin case ENETUNREACH: /* shouldn't happen, checked above */ 56953541Sshin case EHOSTUNREACH: 57053541Sshin case ENETDOWN: 57153541Sshin case EHOSTDOWN: 57253541Sshin default: 57353541Sshin type = ICMP6_DST_UNREACH; 57453541Sshin code = ICMP6_DST_UNREACH_ADDR; 57553541Sshin break; 57653541Sshin } 57753541Sshin icmp6_error(mcopy, type, code, 0); 57853541Sshin return; 57953541Sshin 58053541Sshin freecopy: 58153541Sshin m_freem(mcopy); 58253541Sshin return; 58353541Sshin} 584