/* $OpenBSD: nd6.c,v 1.265 2023/01/24 20:06:16 claudio Exp $ */ /* $KAME: nd6.c,v 1.280 2002/06/08 19:52:07 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 #include #include #include #include #include #include #include #include #include #include #include #include #define ND6_SLOWTIMER_INTERVAL (60 * 60) /* 1 hour */ #define ND6_RECALC_REACHTM_INTERVAL (60 * 120) /* 2 hours */ /* timer values */ int nd6_timer_next = -1; /* at which uptime nd6_timer runs */ time_t nd6_expire_next = -1; /* at which uptime nd6_expire runs */ int nd6_delay = 5; /* delay first probe time 5 second */ int nd6_umaxtries = 3; /* maximum unicast query */ int nd6_mmaxtries = 3; /* maximum multicast query */ int nd6_gctimer = (60 * 60 * 24); /* 1 day: garbage collection timer */ /* preventing too many loops in ND option parsing */ int nd6_maxndopt = 10; /* max # of ND options allowed */ int nd6_maxnudhint = 0; /* max # of subsequent upper layer hints */ #ifdef ND6_DEBUG int nd6_debug = 1; #else int nd6_debug = 0; #endif TAILQ_HEAD(llinfo_nd6_head, llinfo_nd6) nd6_list; struct pool nd6_pool; /* pool for llinfo_nd6 structures */ int nd6_inuse; void nd6_timer(void *); void nd6_slowtimo(void *); void nd6_expire(void *); void nd6_expire_timer(void *); void nd6_invalidate(struct rtentry *); void nd6_free(struct rtentry *); int nd6_llinfo_timer(struct rtentry *); struct timeout nd6_timer_to; struct timeout nd6_slowtimo_ch; struct timeout nd6_expire_timeout; struct task nd6_expire_task; void nd6_init(void) { TAILQ_INIT(&nd6_list); pool_init(&nd6_pool, sizeof(struct llinfo_nd6), 0, IPL_SOFTNET, 0, "nd6", NULL); task_set(&nd6_expire_task, nd6_expire, NULL); /* start timer */ timeout_set_proc(&nd6_timer_to, nd6_timer, NULL); timeout_set_proc(&nd6_slowtimo_ch, nd6_slowtimo, NULL); timeout_add_sec(&nd6_slowtimo_ch, ND6_SLOWTIMER_INTERVAL); timeout_set(&nd6_expire_timeout, nd6_expire_timer, NULL); } void nd6_ifattach(struct ifnet *ifp) { struct nd_ifinfo *nd; nd = malloc(sizeof(*nd), M_IP6NDP, M_WAITOK | M_ZERO); nd->reachable = ND_COMPUTE_RTIME(REACHABLE_TIME); ifp->if_nd = nd; } void nd6_ifdetach(struct ifnet *ifp) { struct nd_ifinfo *nd = ifp->if_nd; free(nd, M_IP6NDP, sizeof(*nd)); } /* * Parse multiple ND options. * This function is much easier to use, for ND routines that do not need * multiple options of the same type. */ int nd6_options(void *opt, int icmp6len, struct nd_opts *ndopts) { struct nd_opt_hdr *nd_opt, *next_opt, *last_opt; int i = 0; bzero(ndopts, sizeof(*ndopts)); if (icmp6len == 0) return 0; next_opt = opt; last_opt = (struct nd_opt_hdr *)((u_char *)opt + icmp6len); while (next_opt != NULL) { int olen; nd_opt = next_opt; /* make sure nd_opt_len is inside the buffer */ if ((caddr_t)&nd_opt->nd_opt_len >= (caddr_t)last_opt) goto invalid; /* every option must have a length greater than zero */ olen = nd_opt->nd_opt_len << 3; if (olen == 0) goto invalid; next_opt = (struct nd_opt_hdr *)((caddr_t)nd_opt + olen); if (next_opt > last_opt) { /* option overruns the end of buffer */ goto invalid; } else if (next_opt == last_opt) { /* reached the end of options chain */ next_opt = NULL; } switch (nd_opt->nd_opt_type) { case ND_OPT_SOURCE_LINKADDR: if (ndopts->nd_opts_src_lladdr != NULL) nd6log((LOG_INFO, "duplicated ND6 option found " "(type=%d)\n", nd_opt->nd_opt_type)); else ndopts->nd_opts_src_lladdr = nd_opt; break; case ND_OPT_TARGET_LINKADDR: if (ndopts->nd_opts_tgt_lladdr != NULL) nd6log((LOG_INFO, "duplicated ND6 option found " "(type=%d)\n", nd_opt->nd_opt_type)); else ndopts->nd_opts_tgt_lladdr = nd_opt; break; case ND_OPT_MTU: case ND_OPT_REDIRECTED_HEADER: case ND_OPT_PREFIX_INFORMATION: case ND_OPT_DNSSL: case ND_OPT_RDNSS: /* Don't warn, not used by kernel */ break; default: /* * Unknown options must be silently ignored, * to accommodate future extension to the protocol. */ nd6log((LOG_DEBUG, "nd6_options: unsupported option %d - " "option ignored\n", nd_opt->nd_opt_type)); break; } i++; if (i > nd6_maxndopt) { icmp6stat_inc(icp6s_nd_toomanyopt); nd6log((LOG_INFO, "too many loop in nd opt\n")); break; } } return 0; invalid: bzero(ndopts, sizeof(*ndopts)); icmp6stat_inc(icp6s_nd_badopt); return -1; } /* * ND6 timer routine to handle ND6 entries */ void nd6_llinfo_settimer(const struct llinfo_nd6 *ln, unsigned int secs) { time_t expire = getuptime() + secs; NET_ASSERT_LOCKED(); KASSERT(!ISSET(ln->ln_rt->rt_flags, RTF_LOCAL)); ln->ln_rt->rt_expire = expire; if (!timeout_pending(&nd6_timer_to) || expire < nd6_timer_next) { nd6_timer_next = expire; timeout_add_sec(&nd6_timer_to, secs); } } void nd6_timer(void *unused) { struct llinfo_nd6 *ln, *nln; time_t expire = getuptime() + nd6_gctimer; int secs; NET_LOCK(); TAILQ_FOREACH_SAFE(ln, &nd6_list, ln_list, nln) { struct rtentry *rt = ln->ln_rt; if (rt->rt_expire && rt->rt_expire <= getuptime()) if (nd6_llinfo_timer(rt)) continue; if (rt->rt_expire && rt->rt_expire < expire) expire = rt->rt_expire; } secs = expire - getuptime(); if (secs < 0) secs = 0; if (!TAILQ_EMPTY(&nd6_list)) { nd6_timer_next = getuptime() + secs; timeout_add_sec(&nd6_timer_to, secs); } NET_UNLOCK(); } /* * ND timer state handling. * * Returns 1 if `rt' should no longer be used, 0 otherwise. */ int nd6_llinfo_timer(struct rtentry *rt) { struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo; struct sockaddr_in6 *dst = satosin6(rt_key(rt)); struct ifnet *ifp; NET_ASSERT_LOCKED(); if ((ifp = if_get(rt->rt_ifidx)) == NULL) return 1; switch (ln->ln_state) { case ND6_LLINFO_INCOMPLETE: if (ln->ln_asked < nd6_mmaxtries) { ln->ln_asked++; nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000); nd6_ns_output(ifp, NULL, &dst->sin6_addr, ln, 0); } else { struct mbuf *m = ln->ln_hold; if (m) { ln->ln_hold = NULL; /* * Fake rcvif to make the ICMP error * more helpful in diagnosing for the * receiver. * XXX: should we consider * older rcvif? */ m->m_pkthdr.ph_ifidx = rt->rt_ifidx; icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR, 0); if (ln->ln_hold == m) { /* m is back in ln_hold. Discard. */ m_freem(ln->ln_hold); ln->ln_hold = NULL; } } nd6_free(rt); ln = NULL; } break; case ND6_LLINFO_REACHABLE: if (!ND6_LLINFO_PERMANENT(ln)) { ln->ln_state = ND6_LLINFO_STALE; nd6_llinfo_settimer(ln, nd6_gctimer); } break; case ND6_LLINFO_STALE: case ND6_LLINFO_PURGE: /* Garbage Collection(RFC 2461 5.3) */ if (!ND6_LLINFO_PERMANENT(ln)) { nd6_free(rt); ln = NULL; } break; case ND6_LLINFO_DELAY: /* We need NUD */ ln->ln_asked = 1; ln->ln_state = ND6_LLINFO_PROBE; nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000); nd6_ns_output(ifp, &dst->sin6_addr, &dst->sin6_addr, ln, 0); break; case ND6_LLINFO_PROBE: if (ln->ln_asked < nd6_umaxtries) { ln->ln_asked++; nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000); nd6_ns_output(ifp, &dst->sin6_addr, &dst->sin6_addr, ln, 0); } else { nd6_free(rt); ln = NULL; } break; } if_put(ifp); return (ln == NULL); } void nd6_expire_timer_update(struct in6_ifaddr *ia6) { time_t expire_time = INT64_MAX; int secs; if (ia6->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) expire_time = ia6->ia6_lifetime.ia6t_expire; if (!(ia6->ia6_flags & IN6_IFF_DEPRECATED) && ia6->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME && expire_time > ia6->ia6_lifetime.ia6t_preferred) expire_time = ia6->ia6_lifetime.ia6t_preferred; if (expire_time == INT64_MAX) return; /* * IFA6_IS_INVALID() and IFA6_IS_DEPRECATED() check for uptime * greater than ia6t_expire or ia6t_preferred, not greater or equal. * Schedule timeout one second later so that either IFA6_IS_INVALID() * or IFA6_IS_DEPRECATED() is true. */ expire_time++; if (!timeout_pending(&nd6_expire_timeout) || nd6_expire_next > expire_time) { secs = expire_time - getuptime(); if (secs < 0) secs = 0; timeout_add_sec(&nd6_expire_timeout, secs); nd6_expire_next = expire_time; } } /* * Expire interface addresses. */ void nd6_expire(void *unused) { struct ifnet *ifp; NET_LOCK(); TAILQ_FOREACH(ifp, &ifnetlist, if_list) { struct ifaddr *ifa, *nifa; struct in6_ifaddr *ia6; TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrlist, ifa_list, nifa) { if (ifa->ifa_addr->sa_family != AF_INET6) continue; ia6 = ifatoia6(ifa); /* check address lifetime */ if (IFA6_IS_INVALID(ia6)) { in6_purgeaddr(&ia6->ia_ifa); } else { if (IFA6_IS_DEPRECATED(ia6)) ia6->ia6_flags |= IN6_IFF_DEPRECATED; nd6_expire_timer_update(ia6); } } } NET_UNLOCK(); } void nd6_expire_timer(void *unused) { task_add(net_tq(0), &nd6_expire_task); } /* * Nuke neighbor cache/prefix/default router management table, right before * ifp goes away. */ void nd6_purge(struct ifnet *ifp) { struct llinfo_nd6 *ln, *nln; NET_ASSERT_LOCKED(); /* * Nuke neighbor cache entries for the ifp. */ TAILQ_FOREACH_SAFE(ln, &nd6_list, ln_list, nln) { struct rtentry *rt; struct sockaddr_dl *sdl; rt = ln->ln_rt; if (rt != NULL && rt->rt_gateway != NULL && rt->rt_gateway->sa_family == AF_LINK) { sdl = satosdl(rt->rt_gateway); if (sdl->sdl_index == ifp->if_index) nd6_free(rt); } } } struct rtentry * nd6_lookup(const struct in6_addr *addr6, int create, struct ifnet *ifp, u_int rtableid) { struct rtentry *rt; struct sockaddr_in6 sin6; int flags; bzero(&sin6, sizeof(sin6)); sin6.sin6_len = sizeof(struct sockaddr_in6); sin6.sin6_family = AF_INET6; sin6.sin6_addr = *addr6; flags = (create) ? RT_RESOLVE : 0; rt = rtalloc(sin6tosa(&sin6), flags, rtableid); if (rt != NULL && (rt->rt_flags & RTF_LLINFO) == 0) { /* * This is the case for the default route. * If we want to create a neighbor cache for the address, we * should free the route for the destination and allocate an * interface route. */ if (create) { rtfree(rt); rt = NULL; } } if (rt == NULL) { if (create && ifp) { struct rt_addrinfo info; struct ifaddr *ifa; int error; /* * If no route is available and create is set, * we allocate a host route for the destination * and treat it like an interface route. * This hack is necessary for a neighbor which can't * be covered by our own prefix. */ ifa = ifaof_ifpforaddr(sin6tosa(&sin6), ifp); if (ifa == NULL) return (NULL); /* * Create a new route. RTF_LLINFO is necessary * to create a Neighbor Cache entry for the * destination in nd6_rtrequest which will be * called in rtrequest. */ bzero(&info, sizeof(info)); info.rti_ifa = ifa; info.rti_flags = RTF_HOST | RTF_LLINFO; info.rti_info[RTAX_DST] = sin6tosa(&sin6); info.rti_info[RTAX_GATEWAY] = sdltosa(ifp->if_sadl); error = rtrequest(RTM_ADD, &info, RTP_CONNECTED, &rt, rtableid); if (error) return (NULL); if (rt->rt_llinfo != NULL) { struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo; ln->ln_state = ND6_LLINFO_NOSTATE; } } else return (NULL); } /* * Validation for the entry. * Note that the check for rt_llinfo is necessary because a cloned * route from a parent route that has the L flag (e.g. the default * route to a p2p interface) may have the flag, too, while the * destination is not actually a neighbor. */ if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || rt->rt_gateway->sa_family != AF_LINK || rt->rt_llinfo == NULL || (ifp != NULL && rt->rt_ifidx != ifp->if_index)) { if (create) { char addr[INET6_ADDRSTRLEN]; nd6log((LOG_DEBUG, "%s: failed to lookup %s (if=%s)\n", __func__, inet_ntop(AF_INET6, addr6, addr, sizeof(addr)), ifp ? ifp->if_xname : "unspec")); } rtfree(rt); return (NULL); } return (rt); } /* * Detect if a given IPv6 address identifies a neighbor on a given link. * XXX: should take care of the destination of a p2p link? */ int nd6_is_addr_neighbor(const struct sockaddr_in6 *addr, struct ifnet *ifp) { struct in6_ifaddr *ia6; struct ifaddr *ifa; struct rtentry *rt; /* * A link-local address is always a neighbor. * XXX: we should use the sin6_scope_id field rather than the embedded * interface index. * XXX: a link does not necessarily specify a single interface. */ if (IN6_IS_ADDR_LINKLOCAL(&addr->sin6_addr) && ntohs(*(u_int16_t *)&addr->sin6_addr.s6_addr[2]) == ifp->if_index) return (1); TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { if (ifa->ifa_addr->sa_family != AF_INET6) continue; ia6 = ifatoia6(ifa); /* Prefix check down below. */ if (ia6->ia6_flags & IN6_IFF_AUTOCONF) continue; if (IN6_ARE_MASKED_ADDR_EQUAL(&addr->sin6_addr, &ia6->ia_addr.sin6_addr, &ia6->ia_prefixmask.sin6_addr)) return (1); } /* * Even if the address matches none of our addresses, it might be * in the neighbor cache. */ rt = nd6_lookup(&addr->sin6_addr, 0, ifp, ifp->if_rdomain); if (rt != NULL) { rtfree(rt); return (1); } return (0); } void nd6_invalidate(struct rtentry *rt) { struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo; struct sockaddr_dl *sdl = satosdl(rt->rt_gateway); m_freem(ln->ln_hold); sdl->sdl_alen = 0; ln->ln_hold = NULL; ln->ln_state = ND6_LLINFO_INCOMPLETE; ln->ln_asked = 0; } /* * Free an nd6 llinfo entry. */ void nd6_free(struct rtentry *rt) { struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo; struct in6_addr in6 = satosin6(rt_key(rt))->sin6_addr; struct ifnet *ifp; NET_ASSERT_LOCKED(); ifp = if_get(rt->rt_ifidx); if (!ip6_forwarding) { if (ln->ln_router) { /* * rt6_flush must be called whether or not the neighbor * is in the Default Router List. * See a corresponding comment in nd6_na_input(). */ rt6_flush(&in6, ifp); } } KASSERT(!ISSET(rt->rt_flags, RTF_LOCAL)); nd6_invalidate(rt); /* * Detach the route from the routing tree and the list of neighbor * caches, and disable the route entry not to be used in already * cached routes. */ if (!ISSET(rt->rt_flags, RTF_STATIC|RTF_CACHED)) rtdeletemsg(rt, ifp, ifp->if_rdomain); if_put(ifp); } /* * Upper-layer reachability hint for Neighbor Unreachability Detection. * * XXX cost-effective methods? */ void nd6_nud_hint(struct rtentry *rt) { struct llinfo_nd6 *ln; struct ifnet *ifp; ifp = if_get(rt->rt_ifidx); if (ifp == NULL) return; if ((rt->rt_flags & RTF_GATEWAY) != 0 || (rt->rt_flags & RTF_LLINFO) == 0 || rt->rt_llinfo == NULL || rt->rt_gateway == NULL || rt->rt_gateway->sa_family != AF_LINK) { /* This is not a host route. */ goto out; } ln = (struct llinfo_nd6 *)rt->rt_llinfo; if (ln->ln_state < ND6_LLINFO_REACHABLE) goto out; /* * if we get upper-layer reachability confirmation many times, * it is possible we have false information. */ ln->ln_byhint++; if (ln->ln_byhint > nd6_maxnudhint) goto out; ln->ln_state = ND6_LLINFO_REACHABLE; if (!ND6_LLINFO_PERMANENT(ln)) nd6_llinfo_settimer(ln, ifp->if_nd->reachable); out: if_put(ifp); } void nd6_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt) { struct sockaddr *gate = rt->rt_gateway; struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo; struct ifaddr *ifa; struct in6_ifaddr *ifa6; if (ISSET(rt->rt_flags, RTF_GATEWAY|RTF_MULTICAST|RTF_MPLS)) return; if (nd6_need_cache(ifp) == 0 && (rt->rt_flags & RTF_HOST) == 0) { /* * This is probably an interface direct route for a link * which does not need neighbor caches (e.g. fe80::%lo0/64). * We do not need special treatment below for such a route. * Moreover, the RTF_LLINFO flag which would be set below * would annoy the ndp(8) command. */ return; } if (req == RTM_RESOLVE && nd6_need_cache(ifp) == 0) { /* * For routing daemons like ospf6d we allow neighbor discovery * based on the cloning route only. This allows us to send * packets directly into a network without having an address * with matching prefix on the interface. If the cloning * route is used for an 6to4 interface, we would mistakenly * make a neighbor cache for the host route, and would see * strange neighbor solicitation for the corresponding * destination. In order to avoid confusion, we check if the * interface is suitable for neighbor discovery, and stop the * process if not. Additionally, we remove the LLINFO flag * so that ndp(8) will not try to get the neighbor information * of the destination. */ rt->rt_flags &= ~RTF_LLINFO; return; } switch (req) { case RTM_ADD: if ((rt->rt_flags & RTF_CLONING) || ((rt->rt_flags & (RTF_LLINFO | RTF_LOCAL)) && ln == NULL)) { if (ln != NULL) nd6_llinfo_settimer(ln, 0); if ((rt->rt_flags & RTF_CLONING) != 0) break; } /* * In IPv4 code, we try to announce new RTF_ANNOUNCE entry here. * We don't do that here since llinfo is not ready yet. * * There are also couple of other things to be discussed: * - unsolicited NA code needs improvement beforehand * - RFC2461 says we MAY send multicast unsolicited NA * (7.2.6 paragraph 4), however, it also says that we * SHOULD provide a mechanism to prevent multicast NA storm. * we don't have anything like it right now. * note that the mechanism needs a mutual agreement * between proxies, which means that we need to implement * a new protocol, or a new kludge. * - from RFC2461 6.2.4, host MUST NOT send an unsolicited NA. * we need to check ip6forwarding before sending it. * (or should we allow proxy ND configuration only for * routers? there's no mention about proxy ND from hosts) */ #if 0 /* XXX it does not work */ if (rt->rt_flags & RTF_ANNOUNCE) nd6_na_output(ifp, &satosin6(rt_key(rt))->sin6_addr, &satosin6(rt_key(rt))->sin6_addr, ip6_forwarding ? ND_NA_FLAG_ROUTER : 0, 1, NULL); #endif /* FALLTHROUGH */ case RTM_RESOLVE: if (gate->sa_family != AF_LINK || gate->sa_len < sizeof(struct sockaddr_dl)) { log(LOG_DEBUG, "%s: bad gateway value: %s\n", __func__, ifp->if_xname); break; } satosdl(gate)->sdl_type = ifp->if_type; satosdl(gate)->sdl_index = ifp->if_index; if (ln != NULL) break; /* This happens on a route change */ /* * Case 2: This route may come from cloning, or a manual route * add with a LL address. */ ln = pool_get(&nd6_pool, PR_NOWAIT | PR_ZERO); rt->rt_llinfo = (caddr_t)ln; if (ln == NULL) { log(LOG_DEBUG, "%s: pool get failed\n", __func__); break; } nd6_inuse++; ln->ln_rt = rt; /* this is required for "ndp" command. - shin */ if (req == RTM_ADD) { /* * gate should have some valid AF_LINK entry, * and ln expire should have some lifetime * which is specified by ndp command. */ ln->ln_state = ND6_LLINFO_REACHABLE; ln->ln_byhint = 0; } else { /* * When req == RTM_RESOLVE, rt is created and * initialized in rtrequest(), so rt_expire is 0. */ ln->ln_state = ND6_LLINFO_NOSTATE; nd6_llinfo_settimer(ln, 0); } rt->rt_flags |= RTF_LLINFO; TAILQ_INSERT_HEAD(&nd6_list, ln, ln_list); /* * If we have too many cache entries, initiate immediate * purging for some "less recently used" entries. Note that * we cannot directly call nd6_free() here because it would * cause re-entering rtable related routines triggering * lock-order-reversal problems. */ if (ip6_neighborgcthresh >= 0 && nd6_inuse >= ip6_neighborgcthresh) { int i; for (i = 0; i < 10; i++) { struct llinfo_nd6 *ln_end; ln_end = TAILQ_LAST(&nd6_list, llinfo_nd6_head); if (ln_end == ln) break; /* Move this entry to the head */ TAILQ_REMOVE(&nd6_list, ln_end, ln_list); TAILQ_INSERT_HEAD(&nd6_list, ln_end, ln_list); if (ND6_LLINFO_PERMANENT(ln_end)) continue; if (ln_end->ln_state > ND6_LLINFO_INCOMPLETE) ln_end->ln_state = ND6_LLINFO_STALE; else ln_end->ln_state = ND6_LLINFO_PURGE; nd6_llinfo_settimer(ln_end, 0); } } /* * check if rt_key(rt) is one of my address assigned * to the interface. */ ifa6 = in6ifa_ifpwithaddr(ifp, &satosin6(rt_key(rt))->sin6_addr); ifa = ifa6 ? &ifa6->ia_ifa : NULL; if (ifa) { ln->ln_state = ND6_LLINFO_REACHABLE; ln->ln_byhint = 0; rt->rt_expire = 0; KASSERT(ifa == rt->rt_ifa); } else if (rt->rt_flags & RTF_ANNOUNCE) { ln->ln_state = ND6_LLINFO_REACHABLE; ln->ln_byhint = 0; rt->rt_expire = 0; /* join solicited node multicast for proxy ND */ if (ifp->if_flags & IFF_MULTICAST) { struct in6_addr llsol; int error; llsol = satosin6(rt_key(rt))->sin6_addr; llsol.s6_addr16[0] = htons(0xff02); llsol.s6_addr16[1] = htons(ifp->if_index); llsol.s6_addr32[1] = 0; llsol.s6_addr32[2] = htonl(1); llsol.s6_addr8[12] = 0xff; if (in6_addmulti(&llsol, ifp, &error)) { char addr[INET6_ADDRSTRLEN]; nd6log((LOG_ERR, "%s: failed to join " "%s (errno=%d)\n", ifp->if_xname, inet_ntop(AF_INET6, &llsol, addr, sizeof(addr)), error)); } } } break; case RTM_DELETE: if (ln == NULL) break; /* leave from solicited node multicast for proxy ND */ if ((rt->rt_flags & RTF_ANNOUNCE) != 0 && (ifp->if_flags & IFF_MULTICAST) != 0) { struct in6_addr llsol; struct in6_multi *in6m; llsol = satosin6(rt_key(rt))->sin6_addr; llsol.s6_addr16[0] = htons(0xff02); llsol.s6_addr16[1] = htons(ifp->if_index); llsol.s6_addr32[1] = 0; llsol.s6_addr32[2] = htonl(1); llsol.s6_addr8[12] = 0xff; IN6_LOOKUP_MULTI(llsol, ifp, in6m); if (in6m) in6_delmulti(in6m); } nd6_inuse--; TAILQ_REMOVE(&nd6_list, ln, ln_list); rt->rt_expire = 0; rt->rt_llinfo = NULL; rt->rt_flags &= ~RTF_LLINFO; m_freem(ln->ln_hold); pool_put(&nd6_pool, ln); break; case RTM_INVALIDATE: if (ln == NULL) break; if (!ISSET(rt->rt_flags, RTF_LOCAL)) nd6_invalidate(rt); break; } } int nd6_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp) { struct in6_ndireq *ndi = (struct in6_ndireq *)data; struct in6_nbrinfo *nbi = (struct in6_nbrinfo *)data; struct rtentry *rt; switch (cmd) { case SIOCGIFINFO_IN6: NET_LOCK_SHARED(); ndi->ndi = *ifp->if_nd; NET_UNLOCK_SHARED(); return (0); case SIOCGNBRINFO_IN6: { struct llinfo_nd6 *ln; struct in6_addr nb_addr = nbi->addr; /* make local for safety */ time_t expire; NET_LOCK_SHARED(); /* * XXX: KAME specific hack for scoped addresses * XXXX: for other scopes than link-local? */ if (IN6_IS_ADDR_LINKLOCAL(&nb_addr) || IN6_IS_ADDR_MC_LINKLOCAL(&nb_addr)) { u_int16_t *idp = (u_int16_t *)&nb_addr.s6_addr[2]; if (*idp == 0) *idp = htons(ifp->if_index); } rt = nd6_lookup(&nb_addr, 0, ifp, ifp->if_rdomain); if (rt == NULL || (ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) { rtfree(rt); NET_UNLOCK_SHARED(); return (EINVAL); } expire = ln->ln_rt->rt_expire; if (expire != 0) { expire -= getuptime(); expire += gettime(); } nbi->state = ln->ln_state; nbi->asked = ln->ln_asked; nbi->isrouter = ln->ln_router; nbi->expire = expire; rtfree(rt); NET_UNLOCK_SHARED(); return (0); } } return (0); } /* * Create neighbor cache entry and cache link-layer address, * on reception of inbound ND6 packets. (RS/RA/NS/redirect) * * type - ICMP6 type * code - type dependent information */ void nd6_cache_lladdr(struct ifnet *ifp, const struct in6_addr *from, char *lladdr, int lladdrlen, int type, int code) { struct rtentry *rt = NULL; struct llinfo_nd6 *ln = NULL; int is_newentry; struct sockaddr_dl *sdl = NULL; int do_update; int olladdr; int llchange; int newstate = 0; if (!ifp) panic("%s: ifp == NULL", __func__); if (!from) panic("%s: from == NULL", __func__); /* nothing must be updated for unspecified address */ if (IN6_IS_ADDR_UNSPECIFIED(from)) return; /* * Validation about ifp->if_addrlen and lladdrlen must be done in * the caller. * * XXX If the link does not have link-layer address, what should * we do? (ifp->if_addrlen == 0) * Spec says nothing in sections for RA, RS and NA. There's small * description on it in NS section (RFC 2461 7.2.3). */ rt = nd6_lookup(from, 0, ifp, ifp->if_rdomain); if (rt == NULL) { rt = nd6_lookup(from, 1, ifp, ifp->if_rdomain); is_newentry = 1; } else { /* do not overwrite local or static entry */ if (ISSET(rt->rt_flags, RTF_STATIC|RTF_LOCAL)) { rtfree(rt); return; } is_newentry = 0; } if (!rt) return; if ((rt->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) != RTF_LLINFO) { fail: nd6_free(rt); rtfree(rt); return; } ln = (struct llinfo_nd6 *)rt->rt_llinfo; if (ln == NULL) goto fail; if (rt->rt_gateway == NULL) goto fail; if (rt->rt_gateway->sa_family != AF_LINK) goto fail; sdl = satosdl(rt->rt_gateway); olladdr = (sdl->sdl_alen) ? 1 : 0; if (olladdr && lladdr) { if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen)) llchange = 1; else llchange = 0; } else llchange = 0; /* * newentry olladdr lladdr llchange (*=record) * 0 n n -- (1) * 0 y n -- (2) * 0 n y -- (3) * STALE * 0 y y n (4) * * 0 y y y (5) * STALE * 1 -- n -- (6) NOSTATE(= PASSIVE) * 1 -- y -- (7) * STALE */ if (llchange) { char addr[INET6_ADDRSTRLEN]; log(LOG_INFO, "ndp info overwritten for %s by %s on %s\n", inet_ntop(AF_INET6, from, addr, sizeof(addr)), ether_sprintf(lladdr), ifp->if_xname); } if (lladdr) { /* (3-5) and (7) */ /* * Record source link-layer address * XXX is it dependent to ifp->if_type? */ sdl->sdl_alen = ifp->if_addrlen; bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen); } if (!is_newentry) { if ((!olladdr && lladdr) || /* (3) */ (olladdr && lladdr && llchange)) { /* (5) */ do_update = 1; newstate = ND6_LLINFO_STALE; } else /* (1-2,4) */ do_update = 0; } else { do_update = 1; if (!lladdr) /* (6) */ newstate = ND6_LLINFO_NOSTATE; else /* (7) */ newstate = ND6_LLINFO_STALE; } if (do_update) { /* * Update the state of the neighbor cache. */ ln->ln_state = newstate; if (ln->ln_state == ND6_LLINFO_STALE) { /* * Since nd6_resolve() in ifp->if_output() will cause * state transition to DELAY and reset the timer, * we must set the timer now, although it is actually * meaningless. */ nd6_llinfo_settimer(ln, nd6_gctimer); if (ln->ln_hold) { struct mbuf *n = ln->ln_hold; ln->ln_hold = NULL; /* * we assume ifp is not a p2p here, so just * set the 2nd argument as the 1st one. */ ifp->if_output(ifp, n, rt_key(rt), rt); if (ln->ln_hold == n) { /* n is back in ln_hold. Discard. */ m_freem(ln->ln_hold); ln->ln_hold = NULL; } } } else if (ln->ln_state == ND6_LLINFO_INCOMPLETE) { /* probe right away */ nd6_llinfo_settimer(ln, 0); } } /* * ICMP6 type dependent behavior. * * NS: clear IsRouter if new entry * RS: clear IsRouter * RA: set IsRouter if there's lladdr * redir: clear IsRouter if new entry * * RA case, (1): * The spec says that we must set IsRouter in the following cases: * - If lladdr exist, set IsRouter. This means (1-5). * - If it is old entry (!newentry), set IsRouter. This means (7). * So, based on the spec, in (1-5) and (7) cases we must set IsRouter. * A question arises for (1) case. (1) case has no lladdr in the * neighbor cache, this is similar to (6). * This case is rare but we figured that we MUST NOT set IsRouter. * * newentry olladdr lladdr llchange NS RS RA redir * D R * 0 n n -- (1) c ? s * 0 y n -- (2) c s s * 0 n y -- (3) c s s * 0 y y n (4) c s s * 0 y y y (5) c s s * 1 -- n -- (6) c c c s * 1 -- y -- (7) c c s c s * * (c=clear s=set) */ switch (type & 0xff) { case ND_NEIGHBOR_SOLICIT: /* * New entry must have is_router flag cleared. */ if (is_newentry) /* (6-7) */ ln->ln_router = 0; break; case ND_REDIRECT: /* * If the icmp is a redirect to a better router, always set the * is_router flag. Otherwise, if the entry is newly created, * clear the flag. [RFC 2461, sec 8.3] */ if (code == ND_REDIRECT_ROUTER) ln->ln_router = 1; else if (is_newentry) /* (6-7) */ ln->ln_router = 0; break; case ND_ROUTER_SOLICIT: /* * is_router flag must always be cleared. */ ln->ln_router = 0; break; case ND_ROUTER_ADVERT: /* * Mark an entry with lladdr as a router. */ if ((!is_newentry && (olladdr || lladdr)) || /* (2-5) */ (is_newentry && lladdr)) { /* (7) */ ln->ln_router = 1; } break; } rtfree(rt); } void nd6_slowtimo(void *ignored_arg) { struct nd_ifinfo *nd6if; struct ifnet *ifp; NET_LOCK(); timeout_add_sec(&nd6_slowtimo_ch, ND6_SLOWTIMER_INTERVAL); TAILQ_FOREACH(ifp, &ifnetlist, if_list) { nd6if = ifp->if_nd; if ((nd6if->recalctm -= ND6_SLOWTIMER_INTERVAL) <= 0) { /* * Since reachable time rarely changes by router * advertisements, we SHOULD insure that a new random * value gets recomputed at least once every few hours. * (RFC 2461, 6.3.4) */ nd6if->recalctm = ND6_RECALC_REACHTM_INTERVAL; nd6if->reachable = ND_COMPUTE_RTIME(REACHABLE_TIME); } } NET_UNLOCK(); } int nd6_resolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, struct sockaddr *dst, u_char *desten) { struct sockaddr_dl *sdl; struct rtentry *rt; struct llinfo_nd6 *ln = NULL; if (m->m_flags & M_MCAST) { ETHER_MAP_IPV6_MULTICAST(&satosin6(dst)->sin6_addr, desten); return (0); } rt = rt_getll(rt0); if (ISSET(rt->rt_flags, RTF_REJECT) && (rt->rt_expire == 0 || getuptime() < rt->rt_expire)) { m_freem(m); return (rt == rt0 ? EHOSTDOWN : EHOSTUNREACH); } /* * Address resolution or Neighbor Unreachability Detection * for the next hop. * At this point, the destination of the packet must be a unicast * or an anycast address(i.e. not a multicast). */ if (!ISSET(rt->rt_flags, RTF_LLINFO)) { char addr[INET6_ADDRSTRLEN]; log(LOG_DEBUG, "%s: %s: route contains no ND information\n", __func__, inet_ntop(AF_INET6, &satosin6(rt_key(rt))->sin6_addr, addr, sizeof(addr))); m_freem(m); return (EINVAL); } if (rt->rt_gateway->sa_family != AF_LINK) { printf("%s: something odd happens\n", __func__); m_freem(m); return (EINVAL); } ln = (struct llinfo_nd6 *)rt->rt_llinfo; KASSERT(ln != NULL); /* * Move this entry to the head of the queue so that it is less likely * for this entry to be a target of forced garbage collection (see * nd6_rtrequest()). */ TAILQ_REMOVE(&nd6_list, ln, ln_list); TAILQ_INSERT_HEAD(&nd6_list, ln, ln_list); /* * The first time we send a packet to a neighbor whose entry is * STALE, we have to change the state to DELAY and set a timer to * expire in DELAY_FIRST_PROBE_TIME seconds to ensure we do * neighbor unreachability detection on expiration. * (RFC 2461 7.3.3) */ if (ln->ln_state == ND6_LLINFO_STALE) { ln->ln_asked = 0; ln->ln_state = ND6_LLINFO_DELAY; nd6_llinfo_settimer(ln, nd6_delay); } /* * If the neighbor cache entry has a state other than INCOMPLETE * (i.e. its link-layer address is already resolved), just * send the packet. */ if (ln->ln_state > ND6_LLINFO_INCOMPLETE) { sdl = satosdl(rt->rt_gateway); if (sdl->sdl_alen != ETHER_ADDR_LEN) { char addr[INET6_ADDRSTRLEN]; log(LOG_DEBUG, "%s: %s: incorrect nd6 information\n", __func__, inet_ntop(AF_INET6, &satosin6(dst)->sin6_addr, addr, sizeof(addr))); m_freem(m); return (EINVAL); } bcopy(LLADDR(sdl), desten, sdl->sdl_alen); return (0); } /* * There is a neighbor cache entry, but no ethernet address * response yet. Replace the held mbuf (if any) with this * latest one. */ if (ln->ln_state == ND6_LLINFO_NOSTATE) ln->ln_state = ND6_LLINFO_INCOMPLETE; m_freem(ln->ln_hold); ln->ln_hold = m; /* * If there has been no NS for the neighbor after entering the * INCOMPLETE state, send the first solicitation. */ if (!ND6_LLINFO_PERMANENT(ln) && ln->ln_asked == 0) { ln->ln_asked++; nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000); nd6_ns_output(ifp, NULL, &satosin6(dst)->sin6_addr, ln, 0); } return (EAGAIN); } int nd6_need_cache(struct ifnet *ifp) { /* * RFC2893 says: * - unidirectional tunnels needs no ND */ switch (ifp->if_type) { case IFT_ETHER: case IFT_IEEE80211: case IFT_CARP: return (1); default: return (0); } }