/* $OpenBSD: in6_src.c,v 1.35 2013/10/23 19:57:50 deraadt Exp $ */ /* $KAME: in6_src.c,v 1.36 2001/02/06 04:08:17 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. */ /* * Copyright (c) 1982, 1986, 1991, 1993 * The Regents of the University of California. 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 University 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 REGENTS 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 REGENTS 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. * * @(#)in_pcb.c 8.2 (Berkeley) 1/4/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *, struct ip6_moptions *, struct route_in6 *, struct ifnet **, u_int); int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *, struct ip6_moptions *, struct route_in6 *, struct ifnet **, struct rtentry **, int, u_int); /* * Return an IPv6 address, which is the most appropriate for a given * destination and user specified options. * If necessary, this function lookups the routing table and returns * an entry to the caller for later use. */ struct in6_addr * in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, struct ip6_moptions *mopts, struct route_in6 *ro, struct in6_addr *laddr, int *errorp, u_int rtableid) { struct ifnet *ifp = NULL; struct in6_addr *dst; struct in6_ifaddr *ia6 = NULL; struct in6_pktinfo *pi = NULL; dst = &dstsock->sin6_addr; *errorp = 0; /* * If the source address is explicitly specified by the caller, * check if the requested source address is indeed a unicast address * assigned to the node, and can be used as the packet's source * address. If everything is okay, use the address as source. */ if (opts && (pi = opts->ip6po_pktinfo) && !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { struct sockaddr_in6 sa6; /* get the outgoing interface */ if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp, rtableid)) != 0) return (NULL); bzero(&sa6, sizeof(sa6)); sa6.sin6_family = AF_INET6; sa6.sin6_len = sizeof(sa6); sa6.sin6_addr = pi->ipi6_addr; if (ifp && IN6_IS_SCOPE_EMBED(&sa6.sin6_addr)) sa6.sin6_addr.s6_addr16[1] = htons(ifp->if_index); ia6 = ifatoia6(ifa_ifwithaddr(sin6tosa(&sa6), rtableid)); if (ia6 == NULL || (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) { *errorp = EADDRNOTAVAIL; return (NULL); } pi->ipi6_addr = sa6.sin6_addr; /* XXX: this overrides pi */ return (&pi->ipi6_addr); } /* * If the source address is not specified but the socket(if any) * is already bound, use the bound address. */ if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) return (laddr); /* * If the caller doesn't specify the source address but * the outgoing interface, use an address associated with * the interface. */ if (pi && pi->ipi6_ifindex) { ifp = if_get(pi->ipi6_ifindex); if (ifp == NULL) { *errorp = ENXIO; /* XXX: better error? */ return (0); } ia6 = in6_ifawithscope(ifp, dst, rtableid); if (ia6 == 0) { *errorp = EADDRNOTAVAIL; return (0); } return (&ia6->ia_addr.sin6_addr); } /* * If the destination address is a link-local unicast address or * a link/interface-local multicast address, and if the outgoing * interface is specified by the sin6_scope_id filed, use an address * associated with the interface. * XXX: We're now trying to define more specific semantics of * sin6_scope_id field, so this part will be rewritten in * the near future. */ if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) || IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) { ifp = if_get(dstsock->sin6_scope_id); if (ifp == NULL) { *errorp = ENXIO; /* XXX: better error? */ return (0); } ia6 = in6_ifawithscope(ifp, dst, rtableid); if (ia6 == 0) { *errorp = EADDRNOTAVAIL; return (0); } return (&ia6->ia_addr.sin6_addr); } /* * If the destination address is a multicast address and * the outgoing interface for the address is specified * by the caller, use an address associated with the interface. * Even if the outgoing interface is not specified, we also * choose a loopback interface as the outgoing interface. */ if (IN6_IS_ADDR_MULTICAST(dst)) { ifp = mopts ? mopts->im6o_multicast_ifp : NULL; if (!ifp && dstsock->sin6_scope_id) ifp = if_get(htons(dstsock->sin6_scope_id)); if (ifp) { ia6 = in6_ifawithscope(ifp, dst, rtableid); if (ia6 == 0) { *errorp = EADDRNOTAVAIL; return (0); } return (&ia6->ia_addr.sin6_addr); } } /* * If the next hop address for the packet is specified * by caller, use an address associated with the route * to the next hop. */ { struct sockaddr_in6 *sin6_next; struct rtentry *rt; if (opts && opts->ip6po_nexthop) { sin6_next = satosin6(opts->ip6po_nexthop); rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL); if (rt) { ia6 = in6_ifawithscope(rt->rt_ifp, dst, rtableid); if (ia6 == 0) ia6 = ifatoia6(rt->rt_ifa); } if (ia6 == 0) { *errorp = EADDRNOTAVAIL; return (0); } return (&ia6->ia_addr.sin6_addr); } } /* * If route is known or can be allocated now, * our src addr is taken from the i/f, else punt. */ if (ro) { if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst))) { RTFREE(ro->ro_rt); ro->ro_rt = (struct rtentry *)0; } if (ro->ro_rt == (struct rtentry *)0 || ro->ro_rt->rt_ifp == (struct ifnet *)0) { struct sockaddr_in6 *sa6; /* No route yet, so try to acquire one */ bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); ro->ro_tableid = rtableid; sa6 = &ro->ro_dst; sa6->sin6_family = AF_INET6; sa6->sin6_len = sizeof(struct sockaddr_in6); sa6->sin6_addr = *dst; sa6->sin6_scope_id = dstsock->sin6_scope_id; if (IN6_IS_ADDR_MULTICAST(dst)) { rtalloc((struct route *)ro); } else { rtalloc_mpath((struct route *)ro, NULL); } } /* * in_pcbconnect() checks out IFF_LOOPBACK to skip using * the address. But we don't know why it does so. * It is necessary to ensure the scope even for lo0 * so doesn't check out IFF_LOOPBACK. */ if (ro->ro_rt) { ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst, rtableid); if (ia6 == 0) /* xxx scope error ?*/ ia6 = ifatoia6(ro->ro_rt->rt_ifa); } #if 0 /* * xxx The followings are necessary? (kazu) * I don't think so. * It's for SO_DONTROUTE option in IPv4.(jinmei) */ if (ia6 == 0) { struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0}; sin6->sin6_addr = *dst; ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6))); if (ia6 == 0) ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6))); if (ia6 == 0) return (0); return (&ia6->ia_addr.sin6_addr); } #endif /* 0 */ if (ia6 == 0) { *errorp = EHOSTUNREACH; /* no route */ return (0); } return (&ia6->ia_addr.sin6_addr); } *errorp = EADDRNOTAVAIL; return (0); } int selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp, struct rtentry **retrt, int norouteok, u_int rtableid) { int error = 0; struct ifnet *ifp = NULL; struct rtentry *rt = NULL; struct sockaddr_in6 *sin6_next; struct in6_pktinfo *pi = NULL; struct in6_addr *dst; dst = &dstsock->sin6_addr; #if 0 if (dstsock->sin6_addr.s6_addr32[0] == 0 && dstsock->sin6_addr.s6_addr32[1] == 0 && !IN6_IS_ADDR_LOOPBACK(&dstsock->sin6_addr)) { printf("in6_selectroute: strange destination %s\n", ip6_sprintf(&dstsock->sin6_addr)); } else { printf("in6_selectroute: destination = %s%%%d\n", ip6_sprintf(&dstsock->sin6_addr), dstsock->sin6_scope_id); /* for debug */ } #endif /* If the caller specify the outgoing interface explicitly, use it. */ if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { ifp = if_get(pi->ipi6_ifindex); if (ifp != NULL && (norouteok || retrt == NULL || IN6_IS_ADDR_MULTICAST(dst))) { /* * we do not have to check or get the route for * multicast. */ goto done; } else goto getroute; } /* * If the destination address is a multicast address and the outgoing * interface for the address is specified by the caller, use it. */ if (IN6_IS_ADDR_MULTICAST(dst) && mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) { goto done; /* we do not need a route for multicast. */ } getroute: /* * If the next hop address for the packet is specified by the caller, * use it as the gateway. */ if (opts && opts->ip6po_nexthop) { struct route_in6 *ron; sin6_next = satosin6(opts->ip6po_nexthop); /* at this moment, we only support AF_INET6 next hops */ if (sin6_next->sin6_family != AF_INET6) { error = EAFNOSUPPORT; /* or should we proceed? */ goto done; } /* * If the next hop is an IPv6 address, then the node identified * by that address must be a neighbor of the sending host. */ ron = &opts->ip6po_nextroute; if ((ron->ro_rt && (ron->ro_rt->rt_flags & (RTF_UP | RTF_GATEWAY)) != RTF_UP) || !IN6_ARE_ADDR_EQUAL(&ron->ro_dst.sin6_addr, &sin6_next->sin6_addr)) { if (ron->ro_rt) { RTFREE(ron->ro_rt); ron->ro_rt = NULL; } ron->ro_dst = *sin6_next; ron->ro_tableid = rtableid; } if (ron->ro_rt == NULL) { rtalloc((struct route *)ron); /* multi path case? */ if (ron->ro_rt == NULL || (ron->ro_rt->rt_flags & RTF_GATEWAY)) { if (ron->ro_rt) { RTFREE(ron->ro_rt); ron->ro_rt = NULL; } error = EHOSTUNREACH; goto done; } } if (!nd6_is_addr_neighbor(sin6_next, ron->ro_rt->rt_ifp)) { RTFREE(ron->ro_rt); ron->ro_rt = NULL; error = EHOSTUNREACH; goto done; } rt = ron->ro_rt; ifp = rt->rt_ifp; /* * When cloning is required, try to allocate a route to the * destination so that the caller can store path MTU * information. */ goto done; } /* * Use a cached route if it exists and is valid, else try to allocate * a new one. Note that we should check the address family of the * cached destination, in case of sharing the cache with IPv4. */ if (ro) { if (ro->ro_rt && (!(ro->ro_rt->rt_flags & RTF_UP) || sin6tosa(&ro->ro_dst)->sa_family != AF_INET6 || !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst))) { RTFREE(ro->ro_rt); ro->ro_rt = (struct rtentry *)NULL; } if (ro->ro_rt == (struct rtentry *)NULL) { struct sockaddr_in6 *sa6; /* No route yet, so try to acquire one */ bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); ro->ro_tableid = rtableid; sa6 = &ro->ro_dst; *sa6 = *dstsock; sa6->sin6_scope_id = 0; ro->ro_tableid = rtableid; rtalloc_mpath((struct route *)ro, NULL); } /* * do not care about the result if we have the nexthop * explicitly specified. */ if (opts && opts->ip6po_nexthop) goto done; if (ro->ro_rt) { ifp = ro->ro_rt->rt_ifp; if (ifp == NULL) { /* can this really happen? */ RTFREE(ro->ro_rt); ro->ro_rt = NULL; } } if (ro->ro_rt == NULL) error = EHOSTUNREACH; rt = ro->ro_rt; /* * Check if the outgoing interface conflicts with * the interface specified by ipi6_ifindex (if specified). * Note that loopback interface is always okay. * (this may happen when we are sending a packet to one of * our own addresses.) */ if (opts && opts->ip6po_pktinfo && opts->ip6po_pktinfo->ipi6_ifindex) { if (!(ifp->if_flags & IFF_LOOPBACK) && ifp->if_index != opts->ip6po_pktinfo->ipi6_ifindex) { error = EHOSTUNREACH; goto done; } } } done: if (ifp == NULL && rt == NULL) { /* * This can happen if the caller did not pass a cached route * nor any other hints. We treat this case an error. */ error = EHOSTUNREACH; } if (error == EHOSTUNREACH) ip6stat.ip6s_noroute++; if (retifp != NULL) *retifp = ifp; if (retrt != NULL) *retrt = rt; /* rt may be NULL */ return (error); } int in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp, u_int rtableid) { struct rtentry *rt = NULL; int error; if ((error = selectroute(dstsock, opts, mopts, ro, retifp, &rt, 1, rtableid)) != 0) return (error); /* * do not use a rejected or black hole route. * XXX: this check should be done in the L2 output routine. * However, if we skipped this check here, we'd see the following * scenario: * - install a rejected route for a scoped address prefix * (like fe80::/10) * - send a packet to a destination that matches the scoped prefix, * with ambiguity about the scope zone. * - pick the outgoing interface from the route, and disambiguate the * scope zone with the interface. * - ip6_output() would try to get another route with the "new" * destination, which may be valid. * - we'd see no error on output. * Although this may not be very harmful, it should still be confusing. * We thus reject the case here. */ if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) return (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); /* * Adjust the "outgoing" interface. If we're going to loop the packet * back to ourselves, the ifp would be the loopback interface. * However, we'd rather know the interface associated to the * destination address (which should probably be one of our own * addresses.) */ if (rt && rt->rt_ifa && rt->rt_ifa->ifa_ifp) *retifp = rt->rt_ifa->ifa_ifp; return (0); } int in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp, struct rtentry **retrt, u_int rtableid) { return (selectroute(dstsock, opts, mopts, ro, retifp, retrt, 0, rtableid)); } /* * Default hop limit selection. The precedence is as follows: * 1. Hoplimit value specified via ioctl. * 2. (If the outgoing interface is detected) the current * hop limit of the interface specified by router advertisement. * 3. The system default hoplimit. */ int in6_selecthlim(struct inpcb *in6p, struct ifnet *ifp) { if (in6p && in6p->inp_hops >= 0) return (in6p->inp_hops); else if (ifp) return (ND_IFINFO(ifp)->chlim); else return (ip6_defhlim); } /* * generate kernel-internal form (scopeid embedded into s6_addr16[1]). * If the address scope of is link-local, embed the interface index in the * address. The routine determines our precedence * between advanced API scope/interface specification and basic API * specification. * * this function should be nuked in the future, when we get rid of * embedded scopeid thing. * * XXX actually, it is over-specification to return ifp against sin6_scope_id. * there can be multiple interfaces that belong to a particular scope zone * (in specification, we have 1:N mapping between a scope zone and interfaces). * we may want to change the function to return something other than ifp. */ int in6_embedscope(in6, sin6, in6p, ifpp) struct in6_addr *in6; const struct sockaddr_in6 *sin6; struct inpcb *in6p; struct ifnet **ifpp; { struct ifnet *ifp = NULL; u_int32_t scopeid; *in6 = sin6->sin6_addr; scopeid = sin6->sin6_scope_id; if (ifpp) *ifpp = NULL; /* * don't try to read sin6->sin6_addr beyond here, since the caller may * ask us to overwrite existing sockaddr_in6 */ if (IN6_IS_SCOPE_EMBED(in6)) { struct in6_pktinfo *pi; /* * KAME assumption: link id == interface id */ if (in6p && in6p->inp_outputopts6 && (pi = in6p->inp_outputopts6->ip6po_pktinfo) && pi->ipi6_ifindex) { ifp = if_get(pi->ipi6_ifindex); if (ifp == NULL) return ENXIO; /* XXX EINVAL? */ in6->s6_addr16[1] = htons(pi->ipi6_ifindex); } else if (in6p && IN6_IS_ADDR_MULTICAST(in6) && in6p->inp_moptions6 && in6p->inp_moptions6->im6o_multicast_ifp) { ifp = in6p->inp_moptions6->im6o_multicast_ifp; in6->s6_addr16[1] = htons(ifp->if_index); } else if (scopeid) { ifp = if_get(scopeid); if (ifp == NULL) return ENXIO; /* XXX EINVAL? */ /*XXX assignment to 16bit from 32bit variable */ in6->s6_addr16[1] = htons(scopeid & 0xffff); } if (ifpp) *ifpp = ifp; } return 0; } /* * generate standard sockaddr_in6 from embedded form. * touches sin6_addr and sin6_scope_id only. * * this function should be nuked in the future, when we get rid of * embedded scopeid thing. */ int in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6, struct ifnet *ifp) { u_int32_t scopeid; sin6->sin6_addr = *in6; /* * don't try to read *in6 beyond here, since the caller may * ask us to overwrite existing sockaddr_in6 */ sin6->sin6_scope_id = 0; if (IN6_IS_SCOPE_EMBED(in6)) { /* * KAME assumption: link id == interface id */ scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]); if (scopeid) { /* sanity check */ if (if_get(scopeid) == NULL) return ENXIO; if (ifp && ifp->if_index != scopeid) return ENXIO; sin6->sin6_addr.s6_addr16[1] = 0; sin6->sin6_scope_id = scopeid; } } return 0; } /* * just clear the embedded scope identifer. */ void in6_clearscope(struct in6_addr *addr) { if (IN6_IS_SCOPE_EMBED(addr)) addr->s6_addr16[1] = 0; }