ip6_forward.c revision 84994
162587Sitojun/* $FreeBSD: head/sys/netinet6/ip6_forward.c 84994 2001-10-15 14:16:18Z darrenr $ */ 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" 3753541Sshin 3853541Sshin#include <sys/param.h> 3953541Sshin#include <sys/systm.h> 4078064Sume#include <sys/malloc.h> 4153541Sshin#include <sys/mbuf.h> 4253541Sshin#include <sys/domain.h> 4353541Sshin#include <sys/protosw.h> 4453541Sshin#include <sys/socket.h> 4553541Sshin#include <sys/errno.h> 4653541Sshin#include <sys/time.h> 4778064Sume#include <sys/kernel.h> 4853541Sshin#include <sys/syslog.h> 4953541Sshin 5053541Sshin#include <net/if.h> 5153541Sshin#include <net/route.h> 5284994Sdarrenr#ifdef PFIL_HOOKS 5384994Sdarrenr#include <net/pfil.h> 5484994Sdarrenr#endif 5553541Sshin 5653541Sshin#include <netinet/in.h> 5753541Sshin#include <netinet/in_var.h> 5878064Sume#include <netinet/in_systm.h> 5978064Sume#include <netinet/ip.h> 6062587Sitojun#include <netinet/ip_var.h> 6178064Sume#include <netinet6/in6_var.h> 6262587Sitojun#include <netinet/ip6.h> 6353541Sshin#include <netinet6/ip6_var.h> 6462587Sitojun#include <netinet/icmp6.h> 6553541Sshin#include <netinet6/nd6.h> 6653541Sshin 6778064Sume#include <netinet/in_pcb.h> 6878064Sume 6963256Sitojun#ifdef IPSEC 7053541Sshin#include <netinet6/ipsec.h> 7178064Sume#ifdef INET6 7262601Sitojun#include <netinet6/ipsec6.h> 7378064Sume#endif 7453541Sshin#include <netkey/key.h> 7563256Sitojun#endif /* IPSEC */ 7653541Sshin 7753541Sshin#include <netinet6/ip6_fw.h> 7853541Sshin 7953541Sshin#include <net/net_osdep.h> 8053541Sshin 8184994Sdarrenr#include <netinet6/ip6protosw.h> 8284994Sdarrenr 8384994Sdarrenrextern struct ip6protosw inet6sw[]; 8484994Sdarrenrextern u_char ip6_protox[IPPROTO_MAX]; 8584994Sdarrenr 8653541Sshinstruct route_in6 ip6_forward_rt; 8753541Sshin 8853541Sshin/* 8953541Sshin * Forward a packet. If some error occurs return the sender 9053541Sshin * an icmp packet. Note we can't always generate a meaningful 9153541Sshin * icmp message because icmp doesn't have a large enough repertoire 9253541Sshin * of codes and types. 9353541Sshin * 9453541Sshin * If not forwarding, just drop the packet. This could be confusing 9553541Sshin * if ipforwarding was zero but some routing protocol was advancing 9653541Sshin * us as a gateway to somewhere. However, we must let the routing 9753541Sshin * protocol deal with that. 9853541Sshin * 9953541Sshin */ 10053541Sshin 10153541Sshinvoid 10253541Sshinip6_forward(m, srcrt) 10353541Sshin struct mbuf *m; 10453541Sshin int srcrt; 10553541Sshin{ 10653541Sshin struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 10778064Sume struct sockaddr_in6 *dst; 10878064Sume struct rtentry *rt; 10953541Sshin int error, type = 0, code = 0; 11062587Sitojun struct mbuf *mcopy = NULL; 11162587Sitojun struct ifnet *origifp; /* maybe unnecessary */ 11284994Sdarrenr#ifdef PFIL_HOOKS 11384994Sdarrenr struct packet_filter_hook *pfh; 11484994Sdarrenr struct mbuf *m1; 11584994Sdarrenr int rv; 11684994Sdarrenr#endif /* PFIL_HOOKS */ 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)) { 13053541Sshin ipsec6stat.in_polvio++; 13153541Sshin m_freem(m); 13253541Sshin return; 13353541Sshin } 13463256Sitojun#endif /*IPSEC*/ 13553541Sshin 13678064Sume /* 13778064Sume * Do not forward packets to multicast destination (should be handled 13878064Sume * by ip6_mforward(). 13978064Sume * Do not forward packets with unspecified source. It was discussed 14078064Sume * in July 2000, on ipngwg mailing list. 14178064Sume */ 14262587Sitojun if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 14378064Sume IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 14478064Sume IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 14553541Sshin ip6stat.ip6s_cantforward++; 14653541Sshin /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 14753541Sshin if (ip6_log_time + ip6_log_interval < time_second) { 14853541Sshin ip6_log_time = time_second; 14953541Sshin log(LOG_DEBUG, 15053541Sshin "cannot forward " 15153541Sshin "from %s to %s nxt %d received on %s\n", 15262587Sitojun ip6_sprintf(&ip6->ip6_src), 15362587Sitojun ip6_sprintf(&ip6->ip6_dst), 15453541Sshin ip6->ip6_nxt, 15553541Sshin if_name(m->m_pkthdr.rcvif)); 15653541Sshin } 15753541Sshin m_freem(m); 15853541Sshin return; 15953541Sshin } 16053541Sshin 16153541Sshin if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 16253541Sshin /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 16353541Sshin icmp6_error(m, ICMP6_TIME_EXCEEDED, 16453541Sshin ICMP6_TIME_EXCEED_TRANSIT, 0); 16553541Sshin return; 16653541Sshin } 16753541Sshin ip6->ip6_hlim -= IPV6_HLIMDEC; 16853541Sshin 16962587Sitojun /* 17062587Sitojun * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 17162587Sitojun * size of IPv6 + ICMPv6 headers) bytes of the packet in case 17262587Sitojun * we need to generate an ICMP6 message to the src. 17362587Sitojun * Thanks to M_EXT, in most cases copy will not occur. 17462587Sitojun * 17562587Sitojun * It is important to save it before IPsec processing as IPsec 17662587Sitojun * processing may modify the mbuf. 17762587Sitojun */ 17862587Sitojun mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 17962587Sitojun 18063256Sitojun#ifdef IPSEC 18153541Sshin /* get a security policy for this packet */ 18278064Sume sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING, 18378064Sume &error); 18453541Sshin if (sp == NULL) { 18553541Sshin ipsec6stat.out_inval++; 18653541Sshin ip6stat.ip6s_cantforward++; 18762587Sitojun if (mcopy) { 18862587Sitojun#if 0 18962587Sitojun /* XXX: what icmp ? */ 19062587Sitojun#else 19162587Sitojun m_freem(mcopy); 19262587Sitojun#endif 19362587Sitojun } 19453541Sshin m_freem(m); 19553541Sshin return; 19653541Sshin } 19753541Sshin 19853541Sshin error = 0; 19953541Sshin 20053541Sshin /* check policy */ 20153541Sshin switch (sp->policy) { 20253541Sshin case IPSEC_POLICY_DISCARD: 20353541Sshin /* 20453541Sshin * This packet is just discarded. 20553541Sshin */ 20653541Sshin ipsec6stat.out_polvio++; 20753541Sshin ip6stat.ip6s_cantforward++; 20853541Sshin key_freesp(sp); 20962587Sitojun if (mcopy) { 21062587Sitojun#if 0 21162587Sitojun /* XXX: what icmp ? */ 21262587Sitojun#else 21362587Sitojun m_freem(mcopy); 21462587Sitojun#endif 21562587Sitojun } 21653541Sshin m_freem(m); 21753541Sshin return; 21853541Sshin 21953541Sshin case IPSEC_POLICY_BYPASS: 22053541Sshin case IPSEC_POLICY_NONE: 22153541Sshin /* no need to do IPsec. */ 22253541Sshin key_freesp(sp); 22353541Sshin goto skip_ipsec; 22462587Sitojun 22553541Sshin case IPSEC_POLICY_IPSEC: 22653541Sshin if (sp->req == NULL) { 22753541Sshin /* XXX should be panic ? */ 22853541Sshin printf("ip6_forward: No IPsec request specified.\n"); 22953541Sshin ip6stat.ip6s_cantforward++; 23053541Sshin key_freesp(sp); 23162587Sitojun if (mcopy) { 23262587Sitojun#if 0 23362587Sitojun /* XXX: what icmp ? */ 23462587Sitojun#else 23562587Sitojun m_freem(mcopy); 23662587Sitojun#endif 23762587Sitojun } 23853541Sshin m_freem(m); 23953541Sshin return; 24053541Sshin } 24153541Sshin /* do IPsec */ 24253541Sshin break; 24353541Sshin 24453541Sshin case IPSEC_POLICY_ENTRUST: 24553541Sshin default: 24653541Sshin /* should be panic ?? */ 24753541Sshin printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 24853541Sshin key_freesp(sp); 24953541Sshin goto skip_ipsec; 25053541Sshin } 25153541Sshin 25253541Sshin { 25353541Sshin struct ipsec_output_state state; 25453541Sshin 25553541Sshin /* 25653541Sshin * All the extension headers will become inaccessible 25753541Sshin * (since they can be encrypted). 25853541Sshin * Don't panic, we need no more updates to extension headers 25953541Sshin * on inner IPv6 packet (since they are now encapsulated). 26053541Sshin * 26153541Sshin * IPv6 [ESP|AH] IPv6 [extension headers] payload 26253541Sshin */ 26353541Sshin bzero(&state, sizeof(state)); 26453541Sshin state.m = m; 26553541Sshin state.ro = NULL; /* update at ipsec6_output_tunnel() */ 26653541Sshin state.dst = NULL; /* update at ipsec6_output_tunnel() */ 26753541Sshin 26853541Sshin error = ipsec6_output_tunnel(&state, sp, 0); 26953541Sshin 27053541Sshin m = state.m; 27153541Sshin key_freesp(sp); 27253541Sshin 27353541Sshin if (error) { 27453541Sshin /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 27553541Sshin switch (error) { 27653541Sshin case EHOSTUNREACH: 27753541Sshin case ENETUNREACH: 27853541Sshin case EMSGSIZE: 27953541Sshin case ENOBUFS: 28053541Sshin case ENOMEM: 28153541Sshin break; 28253541Sshin default: 28353541Sshin printf("ip6_output (ipsec): error code %d\n", error); 28453541Sshin /*fall through*/ 28553541Sshin case ENOENT: 28653541Sshin /* don't show these error codes to the user */ 28753541Sshin break; 28853541Sshin } 28953541Sshin ip6stat.ip6s_cantforward++; 29062587Sitojun if (mcopy) { 29162587Sitojun#if 0 29262587Sitojun /* XXX: what icmp ? */ 29362587Sitojun#else 29462587Sitojun m_freem(mcopy); 29562587Sitojun#endif 29662587Sitojun } 29753541Sshin m_freem(m); 29853541Sshin return; 29953541Sshin } 30053541Sshin } 30153541Sshin skip_ipsec: 30263256Sitojun#endif /* IPSEC */ 30353541Sshin 30478064Sume dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst; 30553541Sshin if (!srcrt) { 30653541Sshin /* 30753541Sshin * ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst 30853541Sshin */ 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 } 31553541Sshin /* this probably fails but give it a try again */ 31653541Sshin rtalloc_ign((struct route *)&ip6_forward_rt, 31753541Sshin RTF_PRCLONING); 31853541Sshin } 31962587Sitojun 32053541Sshin if (ip6_forward_rt.ro_rt == 0) { 32153541Sshin ip6stat.ip6s_noroute++; 32278064Sume in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 32362587Sitojun if (mcopy) { 32462587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 32562587Sitojun ICMP6_DST_UNREACH_NOROUTE, 0); 32662587Sitojun } 32762587Sitojun m_freem(m); 32853541Sshin return; 32953541Sshin } 33053541Sshin } else if ((rt = ip6_forward_rt.ro_rt) == 0 || 33153541Sshin !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 33253541Sshin if (ip6_forward_rt.ro_rt) { 33353541Sshin RTFREE(ip6_forward_rt.ro_rt); 33453541Sshin ip6_forward_rt.ro_rt = 0; 33553541Sshin } 33653541Sshin bzero(dst, sizeof(*dst)); 33753541Sshin dst->sin6_len = sizeof(struct sockaddr_in6); 33853541Sshin dst->sin6_family = AF_INET6; 33953541Sshin dst->sin6_addr = ip6->ip6_dst; 34053541Sshin 34153541Sshin rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING); 34253541Sshin if (ip6_forward_rt.ro_rt == 0) { 34353541Sshin ip6stat.ip6s_noroute++; 34478064Sume in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 34562587Sitojun if (mcopy) { 34662587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 34762587Sitojun ICMP6_DST_UNREACH_NOROUTE, 0); 34862587Sitojun } 34962587Sitojun m_freem(m); 35053541Sshin return; 35153541Sshin } 35253541Sshin } 35353541Sshin rt = ip6_forward_rt.ro_rt; 35462587Sitojun 35562587Sitojun /* 35662587Sitojun * Scope check: if a packet can't be delivered to its destination 35762587Sitojun * for the reason that the destination is beyond the scope of the 35862587Sitojun * source address, discard the packet and return an icmp6 destination 35962587Sitojun * unreachable error with Code 2 (beyond scope of source address). 36062587Sitojun * [draft-ietf-ipngwg-icmp-v3-00.txt, Section 3.1] 36162587Sitojun */ 36262587Sitojun if (in6_addr2scopeid(m->m_pkthdr.rcvif, &ip6->ip6_src) != 36362587Sitojun in6_addr2scopeid(rt->rt_ifp, &ip6->ip6_src)) { 36462587Sitojun ip6stat.ip6s_cantforward++; 36562587Sitojun ip6stat.ip6s_badscope++; 36662587Sitojun in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 36762587Sitojun 36862587Sitojun if (ip6_log_time + ip6_log_interval < time_second) { 36962587Sitojun ip6_log_time = time_second; 37062587Sitojun log(LOG_DEBUG, 37162587Sitojun "cannot forward " 37262587Sitojun "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 37362587Sitojun ip6_sprintf(&ip6->ip6_src), 37462587Sitojun ip6_sprintf(&ip6->ip6_dst), 37562587Sitojun ip6->ip6_nxt, 37662587Sitojun if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 37762587Sitojun } 37862587Sitojun if (mcopy) 37962587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 38062587Sitojun ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 38162587Sitojun m_freem(m); 38262587Sitojun return; 38362587Sitojun } 38462587Sitojun 38562587Sitojun if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { 38653541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 38762587Sitojun if (mcopy) { 38862587Sitojun u_long mtu; 38963256Sitojun#ifdef IPSEC 39062587Sitojun struct secpolicy *sp; 39162587Sitojun int ipsecerror; 39262587Sitojun size_t ipsechdrsiz; 39362587Sitojun#endif 39462587Sitojun 39562587Sitojun mtu = rt->rt_ifp->if_mtu; 39663256Sitojun#ifdef IPSEC 39762587Sitojun /* 39862587Sitojun * When we do IPsec tunnel ingress, we need to play 39962587Sitojun * with if_mtu value (decrement IPsec header size 40062587Sitojun * from mtu value). The code is much simpler than v4 40162587Sitojun * case, as we have the outgoing interface for 40262587Sitojun * encapsulated packet as "rt->rt_ifp". 40362587Sitojun */ 40462587Sitojun sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 40562587Sitojun IP_FORWARDING, &ipsecerror); 40662587Sitojun if (sp) { 40762587Sitojun ipsechdrsiz = ipsec6_hdrsiz(mcopy, 40862587Sitojun IPSEC_DIR_OUTBOUND, NULL); 40962587Sitojun if (ipsechdrsiz < mtu) 41062587Sitojun mtu -= ipsechdrsiz; 41162587Sitojun } 41262587Sitojun 41362587Sitojun /* 41462587Sitojun * if mtu becomes less than minimum MTU, 41562587Sitojun * tell minimum MTU (and I'll need to fragment it). 41662587Sitojun */ 41762587Sitojun if (mtu < IPV6_MMTU) 41862587Sitojun mtu = IPV6_MMTU; 41962587Sitojun#endif 42062587Sitojun icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 42162587Sitojun } 42262587Sitojun m_freem(m); 42353541Sshin return; 42453541Sshin } 42553541Sshin 42653541Sshin if (rt->rt_flags & RTF_GATEWAY) 42753541Sshin dst = (struct sockaddr_in6 *)rt->rt_gateway; 42853541Sshin 42953541Sshin /* 43053541Sshin * If we are to forward the packet using the same interface 43153541Sshin * as one we got the packet from, perhaps we should send a redirect 43253541Sshin * to sender to shortcut a hop. 43353541Sshin * Only send redirect if source is sending directly to us, 43453541Sshin * and if packet was not source routed (or has any options). 43553541Sshin * Also, don't send redirect if forwarding using a route 43653541Sshin * modified by a redirect. 43753541Sshin */ 43853541Sshin if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 43978064Sume (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 44078064Sume if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 44178064Sume /* 44278064Sume * If the incoming interface is equal to the outgoing 44378064Sume * one, and the link attached to the interface is 44478064Sume * point-to-point, then it will be highly probable 44578064Sume * that a routing loop occurs. Thus, we immediately 44678064Sume * drop the packet and send an ICMPv6 error message. 44778064Sume * 44878064Sume * type/code is based on suggestion by Rich Draves. 44978064Sume * not sure if it is the best pick. 45078064Sume */ 45178064Sume icmp6_error(mcopy, ICMP6_DST_UNREACH, 45278064Sume ICMP6_DST_UNREACH_ADDR, 0); 45378064Sume m_freem(m); 45478064Sume return; 45578064Sume } 45653541Sshin type = ND_REDIRECT; 45778064Sume } 45853541Sshin 45953541Sshin /* 46053541Sshin * Check with the firewall... 46153541Sshin */ 46266303Sume if (ip6_fw_enable && ip6_fw_chk_ptr) { 46353541Sshin u_short port = 0; 46453541Sshin /* If ipfw says divert, we have to just drop packet */ 46553541Sshin if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) { 46653541Sshin m_freem(m); 46753541Sshin goto freecopy; 46853541Sshin } 46953541Sshin if (!m) 47053541Sshin goto freecopy; 47153541Sshin } 47253541Sshin 47362587Sitojun /* 47462587Sitojun * Fake scoped addresses. Note that even link-local source or 47562587Sitojun * destinaion can appear, if the originating node just sends the 47662587Sitojun * packet to us (without address resolution for the destination). 47762587Sitojun * Since both icmp6_error and icmp6_redirect_output fill the embedded 47878064Sume * link identifiers, we can do this stuff after making a copy for 47978064Sume * returning an error. 48062587Sitojun */ 48162587Sitojun if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 48262587Sitojun /* 48362587Sitojun * See corresponding comments in ip6_output. 48462587Sitojun * XXX: but is it possible that ip6_forward() sends a packet 48562587Sitojun * to a loopback interface? I don't think so, and thus 48662587Sitojun * I bark here. (jinmei@kame.net) 48762587Sitojun * XXX: it is common to route invalid packets to loopback. 48862587Sitojun * also, the codepath will be visited on use of ::1 in 48962587Sitojun * rthdr. (itojun) 49062587Sitojun */ 49162587Sitojun#if 1 49262587Sitojun if (0) 49362587Sitojun#else 49462587Sitojun if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 49562587Sitojun#endif 49662587Sitojun { 49762587Sitojun printf("ip6_forward: outgoing interface is loopback. " 49862587Sitojun "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 49962587Sitojun ip6_sprintf(&ip6->ip6_src), 50062587Sitojun ip6_sprintf(&ip6->ip6_dst), 50162587Sitojun ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 50262587Sitojun if_name(rt->rt_ifp)); 50362587Sitojun } 50462587Sitojun 50578064Sume /* we can just use rcvif in forwarding. */ 50678064Sume origifp = m->m_pkthdr.rcvif; 50762587Sitojun } 50862587Sitojun else 50962587Sitojun origifp = rt->rt_ifp; 51078064Sume#ifndef SCOPEDROUTING 51178064Sume /* 51278064Sume * clear embedded scope identifiers if necessary. 51378064Sume * in6_clearscope will touch the addresses only when necessary. 51478064Sume */ 51578064Sume in6_clearscope(&ip6->ip6_src); 51678064Sume in6_clearscope(&ip6->ip6_dst); 51762587Sitojun#endif 51862587Sitojun 51984994Sdarrenr#ifdef PFIL_HOOKS 52084994Sdarrenr /* 52184994Sdarrenr * Run through list of hooks for output packets. 52284994Sdarrenr */ 52384994Sdarrenr m1 = m; 52484994Sdarrenr pfh = pfil_hook_get(PFIL_OUT, &inet6sw[ip6_protox[IPPROTO_IPV6]].pr_pfh); 52584994Sdarrenr for (; pfh; pfh = pfh->pfil_link.tqe_next) 52684994Sdarrenr if (pfh->pfil_func) { 52784994Sdarrenr rv = pfh->pfil_func(ip6, sizeof(*ip6), 52884994Sdarrenr rt->rt_ifp, 1, &m1); 52984994Sdarrenr if (rv) { 53084994Sdarrenr error = EHOSTUNREACH; 53184994Sdarrenr goto freecopy; 53284994Sdarrenr } 53384994Sdarrenr m = m1; 53484994Sdarrenr if (m == NULL) 53584994Sdarrenr goto freecopy; 53684994Sdarrenr ip6 = mtod(m, struct ip6_hdr *); 53784994Sdarrenr } 53884994Sdarrenr#endif /* PFIL_HOOKS */ 53984994Sdarrenr 54062587Sitojun error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 54153541Sshin if (error) { 54253541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 54353541Sshin ip6stat.ip6s_cantforward++; 54453541Sshin } else { 54553541Sshin ip6stat.ip6s_forward++; 54653541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 54753541Sshin if (type) 54853541Sshin ip6stat.ip6s_redirectsent++; 54953541Sshin else { 55053541Sshin if (mcopy) 55153541Sshin goto freecopy; 55253541Sshin } 55353541Sshin } 55453541Sshin if (mcopy == NULL) 55553541Sshin return; 55653541Sshin 55753541Sshin switch (error) { 55853541Sshin case 0: 55962587Sitojun#if 1 56053541Sshin if (type == ND_REDIRECT) { 56153541Sshin icmp6_redirect_output(mcopy, rt); 56253541Sshin return; 56353541Sshin } 56462587Sitojun#endif 56553541Sshin goto freecopy; 56653541Sshin 56753541Sshin case EMSGSIZE: 56853541Sshin /* xxx MTU is constant in PPP? */ 56953541Sshin goto freecopy; 57053541Sshin 57153541Sshin case ENOBUFS: 57253541Sshin /* Tell source to slow down like source quench in IP? */ 57353541Sshin goto freecopy; 57453541Sshin 57553541Sshin case ENETUNREACH: /* shouldn't happen, checked above */ 57653541Sshin case EHOSTUNREACH: 57753541Sshin case ENETDOWN: 57853541Sshin case EHOSTDOWN: 57953541Sshin default: 58053541Sshin type = ICMP6_DST_UNREACH; 58153541Sshin code = ICMP6_DST_UNREACH_ADDR; 58253541Sshin break; 58353541Sshin } 58453541Sshin icmp6_error(mcopy, type, code, 0); 58553541Sshin return; 58653541Sshin 58753541Sshin freecopy: 58853541Sshin m_freem(mcopy); 58953541Sshin return; 59053541Sshin} 591