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