void ip6_forward(struct mbuf *m, int srcrt) { struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); struct sockaddr_in6 *dst; struct rtentry *rt; int error, type = 0, code = 0; struct mbuf *mcopy = NULL; struct ifnet *origifp; /* maybe unnecessary */ #ifdef IPSEC struct secpolicy *sp = NULL; #endif #ifdef IPSEC /* * Check AH/ESP integrity. */ /* * Don't increment ip6s_cantforward because this is the check * before forwarding packet actually. */ if (ipsec6_in_reject(m, NULL)) { #if !defined(FAST_IPSEC) ipsec6stat.in_polvio++; #endif m_freem(m); return; } #endif /* IPSEC */ /* * 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)) { ip6stat.ip6s_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 IPSEC /* get a security policy for this packet */ sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING, &error); if (sp == NULL) { ipsec6stat.out_inval++; ip6stat.ip6s_cantforward++; if (mcopy) { #if 0 /* XXX: what icmp ? */ #else m_freem(mcopy); #endif } m_freem(m); return; } error = 0; /* check policy */ switch (sp->policy) { case IPSEC_POLICY_DISCARD: /* * This packet is just discarded. */ ipsec6stat.out_polvio++; ip6stat.ip6s_cantforward++; key_freesp(sp); if (mcopy) { #if 0 /* XXX: what icmp ? */ #else m_freem(mcopy); #endif } m_freem(m); return; case IPSEC_POLICY_BYPASS: case IPSEC_POLICY_NONE: /* no need to do IPsec. */ key_freesp(sp); goto skip_ipsec; case IPSEC_POLICY_IPSEC: if (sp->req == NULL) { /* XXX should be panic ? */ kprintf("ip6_forward: No IPsec request specified.\n"); ip6stat.ip6s_cantforward++; key_freesp(sp); if (mcopy) { #if 0 /* XXX: what icmp ? */ #else m_freem(mcopy); #endif } m_freem(m); return; } /* do IPsec */ break; case IPSEC_POLICY_ENTRUST: default: /* should be panic ?? */ kprintf("ip6_forward: Invalid policy found. %d\n", sp->policy); key_freesp(sp); goto skip_ipsec; } { struct ipsec_output_state state; /* * All the extension headers will become inaccessible * (since they can be encrypted). * Don't panic, we need no more updates to extension headers * on inner IPv6 packet (since they are now encapsulated). * * IPv6 [ESP|AH] IPv6 [extension headers] payload */ bzero(&state, sizeof(state)); state.m = m; state.ro = NULL; /* update at ipsec6_output_tunnel() */ state.dst = NULL; /* update at ipsec6_output_tunnel() */ error = ipsec6_output_tunnel(&state, sp, 0); m = state.m; key_freesp(sp); if (error) { /* mbuf is already reclaimed in ipsec6_output_tunnel. */ switch (error) { case EHOSTUNREACH: case ENETUNREACH: case EMSGSIZE: case ENOBUFS: case ENOMEM: break; default: kprintf("ip6_output (ipsec): error code %d\n", error); /* fall through */ case ENOENT: /* don't show these error codes to the user */ break; } ip6stat.ip6s_cantforward++; if (mcopy) { #if 0 /* XXX: what icmp ? */ #else m_freem(mcopy); #endif } m_freem(m); return; } } skip_ipsec: #endif /* IPSEC */ dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst; if (!srcrt) { /* * ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */ if (ip6_forward_rt.ro_rt == NULL || !(ip6_forward_rt.ro_rt->rt_flags & RTF_UP)) { if (ip6_forward_rt.ro_rt) { RTFREE(ip6_forward_rt.ro_rt); ip6_forward_rt.ro_rt = 0; } /* this probably fails but give it a try again */ rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING); } if (ip6_forward_rt.ro_rt == NULL) { ip6stat.ip6s_noroute++; in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); if (mcopy) { icmp6_error(mcopy, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE, 0); } m_freem(m); return; } } else if ((rt = ip6_forward_rt.ro_rt) == NULL || !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { if (ip6_forward_rt.ro_rt) { RTFREE(ip6_forward_rt.ro_rt); ip6_forward_rt.ro_rt = 0; } bzero(dst, sizeof(*dst)); dst->sin6_len = sizeof(struct sockaddr_in6); dst->sin6_family = AF_INET6; dst->sin6_addr = ip6->ip6_dst; rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING); if (ip6_forward_rt.ro_rt == NULL) { ip6stat.ip6s_noroute++; in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); if (mcopy) { icmp6_error(mcopy, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE, 0); } m_freem(m); return; } } rt = ip6_forward_rt.ro_rt; /* * 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). * [draft-ietf-ipngwg-icmp-v3-02.txt, Section 3.1] */ if (in6_addr2scopeid(m->m_pkthdr.rcvif, &ip6->ip6_src) != in6_addr2scopeid(rt->rt_ifp, &ip6->ip6_src)) { ip6stat.ip6s_cantforward++; ip6stat.ip6s_badscope++; 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; } if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); if (mcopy) { u_long mtu; #ifdef IPSEC struct secpolicy *sp; int ipsecerror; size_t ipsechdrsiz; #endif mtu = rt->rt_ifp->if_mtu; #ifdef IPSEC /* * When we do IPsec tunnel ingress, we need to play * with if_mtu value (decrement IPsec header size * from mtu value). The code is much simpler than v4 * case, as we have the outgoing interface for * encapsulated packet as "rt->rt_ifp". */ sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, IP_FORWARDING, &ipsecerror); if (sp) { ipsechdrsiz = ipsec6_hdrsiz(mcopy, IPSEC_DIR_OUTBOUND, NULL); if (ipsechdrsiz < mtu) mtu -= ipsechdrsiz; } /* * if mtu becomes less than minimum MTU, * tell minimum MTU (and I'll need to fragment it). */ if (mtu < IPV6_MMTU) mtu = IPV6_MMTU; #endif 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 && (rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) == 0) { if (rt->rt_ifp->if_flags & IFF_POINTOPOINT) { /* * If the incoming interface is equal to the outgoing * one, and the link attached to the interface is * point-to-point, then it will be highly probable * that a routing loop occurs. Thus, we immediately * drop the packet and send an ICMPv6 error message. * * 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; } /* * Check with the firewall... */ if (ip6_fw_enable && ip6_fw_chk_ptr) { u_short port = 0; /* If ipfw says divert, we have to just drop packet */ if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) { m_freem(m); goto freecopy; } if (!m) goto freecopy; } /* * 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) { /* * 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. ([email protected]) * 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 { kprintf("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); /* * Run through list of hooks for output packets. */ if (pfil_has_hooks(&inet6_pfil_hook)) { error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT); if (error != 0) goto senderr; if (m == NULL) goto freecopy; ip6 = mtod(m, struct ip6_hdr *); }
void ip6_forward(struct mbuf *m, int srcrt) { struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); struct sockaddr_in6 *dst; struct rtentry *rt; int error = 0, type = 0, code = 0; struct mbuf *mcopy = NULL; struct ifnet *origifp; /* maybe unnecessary */ #ifdef IPSEC u_int8_t sproto = 0; struct m_tag *mtag; union sockaddr_union sdst; struct tdb_ident *tdbi; u_int32_t sspi; struct tdb *tdb; int s; #if NPF > 0 struct ifnet *encif; #endif #endif /* IPSEC */ u_int rtableid = 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)) { ip6stat.ip6s_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, m->m_pkthdr.rcvif->if_xname); } 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; #if NPF > 0 reroute: #endif #ifdef IPSEC if (!ipsec_in_use) goto done_spd; s = splnet(); /* * Check if there was an outgoing SA bound to the flow * from a transport protocol. */ /* Do we have any pending SAs to apply ? */ mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); if (mtag != NULL) { #ifdef DIAGNOSTIC if (mtag->m_tag_len != sizeof (struct tdb_ident)) panic("ip6_forward: tag of length %d (should be %d", mtag->m_tag_len, sizeof (struct tdb_ident)); #endif tdbi = (struct tdb_ident *)(mtag + 1); tdb = gettdb(tdbi->rdomain, tdbi->spi, &tdbi->dst, tdbi->proto); if (tdb == NULL) error = -EINVAL; m_tag_delete(m, mtag); } else tdb = ipsp_spd_lookup(m, AF_INET6, sizeof(struct ip6_hdr), &error, IPSP_DIRECTION_OUT, NULL, NULL); if (tdb == NULL) { splx(s); if (error == 0) { /* * No IPsec processing required, we'll just send the * packet out. */ sproto = 0; /* Fall through to routing/multicast handling */ } else { /* * -EINVAL is used to indicate that the packet should * be silently dropped, typically because we've asked * key management for an SA. */ if (error == -EINVAL) /* Should silently drop packet */ error = 0; goto freecopy; } } else { /* Loop detection */ for (mtag = m_tag_first(m); mtag != NULL; mtag = m_tag_next(m, mtag)) { if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE && mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED) continue; tdbi = (struct tdb_ident *)(mtag + 1); if (tdbi->spi == tdb->tdb_spi && tdbi->proto == tdb->tdb_sproto && tdbi->rdomain == tdb->tdb_rdomain && !bcmp(&tdbi->dst, &tdb->tdb_dst, sizeof(union sockaddr_union))) { splx(s); sproto = 0; /* mark as no-IPsec-needed */ goto done_spd; } } /* We need to do IPsec */ bcopy(&tdb->tdb_dst, &sdst, sizeof(sdst)); sspi = tdb->tdb_spi; sproto = tdb->tdb_sproto; splx(s); } /* Fall through to the routing/multicast handling code */ done_spd: #endif /* IPSEC */ #if NPF > 0 rtableid = m->m_pkthdr.rdomain; #endif /* * 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)); dst = &ip6_forward_rt.ro_dst; if (!srcrt) { /* * ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */ if (ip6_forward_rt.ro_rt == 0 || (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0 || ip6_forward_rt.ro_tableid != rtableid) { if (ip6_forward_rt.ro_rt) { RTFREE(ip6_forward_rt.ro_rt); ip6_forward_rt.ro_rt = 0; } /* this probably fails but give it a try again */ ip6_forward_rt.ro_tableid = rtableid; rtalloc_mpath((struct route *)&ip6_forward_rt, &ip6->ip6_src.s6_addr32[0]); } if (ip6_forward_rt.ro_rt == 0) { ip6stat.ip6s_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 (ip6_forward_rt.ro_rt == 0 || (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0 || !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr) || ip6_forward_rt.ro_tableid != rtableid) { if (ip6_forward_rt.ro_rt) { RTFREE(ip6_forward_rt.ro_rt); ip6_forward_rt.ro_rt = 0; } bzero(dst, sizeof(*dst)); dst->sin6_len = sizeof(struct sockaddr_in6); dst->sin6_family = AF_INET6; dst->sin6_addr = ip6->ip6_dst; ip6_forward_rt.ro_tableid = rtableid; rtalloc_mpath((struct route *)&ip6_forward_rt, &ip6->ip6_src.s6_addr32[0]); if (ip6_forward_rt.ro_rt == 0) { ip6stat.ip6s_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; } } rt = ip6_forward_rt.ro_rt; /* * 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). * [draft-ietf-ipngwg-icmp-v3-00.txt, Section 3.1] */ if (in6_addr2scopeid(m->m_pkthdr.rcvif, &ip6->ip6_src) != in6_addr2scopeid(rt->rt_ifp, &ip6->ip6_src)) { ip6stat.ip6s_cantforward++; ip6stat.ip6s_badscope++; 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, m->m_pkthdr.rcvif->if_xname, rt->rt_ifp->if_xname); } if (mcopy) icmp6_error(mcopy, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_BEYONDSCOPE, 0); m_freem(m); goto freert; } #ifdef IPSEC /* * Check if the packet needs encapsulation. * ipsp_process_packet will never come back to here. * XXX ipsp_process_packet() calls ip6_output(), and there'll be no * PMTU notification. is it okay? */ if (sproto != 0) { s = splnet(); tdb = gettdb(rtable_l2(m->m_pkthdr.rdomain), sspi, &sdst, sproto); if (tdb == NULL) { splx(s); error = EHOSTUNREACH; m_freem(m); goto senderr; /*XXX*/ } #if NPF > 0 if ((encif = enc_getif(tdb->tdb_rdomain, tdb->tdb_tap)) == NULL || pf_test6(PF_FWD, encif, &m, NULL) != PF_PASS) { splx(s); error = EHOSTUNREACH; m_freem(m); goto senderr; } if (m == NULL) { splx(s); goto senderr; } ip6 = mtod(m, struct ip6_hdr *); /* * PF_TAG_REROUTE handling or not... * Packet is entering IPsec so the routing is * already overruled by the IPsec policy. * Until now the change was not reconsidered. * What's the behaviour? */ #endif m->m_flags &= ~(M_BCAST | M_MCAST); /* just in case */ /* Callee frees mbuf */ error = ipsp_process_packet(m, tdb, AF_INET6, 0); splx(s); m_freem(mcopy); goto freert; }