Edit
IABSD.fr/src/sys/netinet6/nd6_nbr.c
florian
- sys/netinet6/nd6_nbr.c
-
/* $OpenBSD: nd6_nbr.c,v 1.165 2025/09/16 09:52:49 florian Exp $ */ /* $KAME: nd6_nbr.c,v 1.61 2001/02/10 16:06:14 jinmei 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 <sys/param.h> #include <sys/systm.h> #include <sys/malloc.h> #include <sys/mbuf.h> #include <sys/socket.h> #include <sys/syslog.h> #include <sys/queue.h> #include <sys/timeout.h> #include <net/if.h> #include <net/if_var.h> #include <net/if_types.h> #include <net/if_dl.h> #include <net/route.h> #include <netinet/in.h> #include <netinet/if_ether.h> #include <netinet6/in6_var.h> #include <netinet/ip6.h> #include <netinet6/ip6_var.h> #include <netinet6/nd6.h> #include <netinet/icmp6.h> #include "carp.h" #if NCARP > 0 #include <netinet/ip_carp.h> #endif static TAILQ_HEAD(, dadq) dadq = TAILQ_HEAD_INITIALIZER(dadq); /* list of addresses to run DAD on */ struct dadq { TAILQ_ENTRY(dadq) dad_list; struct ifaddr *dad_ifa; int dad_count; /* max NS to send */ int dad_ns_tcount; /* # of trials to send NS */ int dad_ns_ocount; /* NS sent so far */ int dad_ns_icount; int dad_na_icount; struct timeout dad_timer_ch; }; struct dadq *nd6_dad_find(struct ifaddr *); void nd6_dad_destroy(struct dadq *); void nd6_dad_reaper(void *); void nd6_dad_starttimer(struct dadq *); void nd6_dad_stoptimer(struct dadq *); void nd6_dad_timer(void *); void nd6_dad_ns_output(struct dadq *, struct ifaddr *); void nd6_dad_ns_input(struct ifaddr *); void nd6_dad_duplicated(struct dadq *); int nd6_isneighbor(const struct ifnet *, const struct in6_addr *); static int dad_maxtry = 15; /* max # of *tries* to transmit DAD packet */ /* * Input an Neighbor Solicitation Message. * * Based on RFC 2461 * Based on RFC 2462 (duplicated address detection) */ void nd6_ns_input(struct mbuf *m, int off, int icmp6len) { struct ifnet *ifp; struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); struct nd_neighbor_solicit *nd_ns; struct in6_addr saddr6 = ip6->ip6_src; struct in6_addr daddr6 = ip6->ip6_dst; struct in6_addr taddr6; struct in6_addr myaddr6; char *lladdr = NULL; struct ifaddr *ifa = NULL; int lladdrlen = 0; int anycast = 0, proxy = 0, tentative = 0; int i_am_router = (atomic_load_int(&ip6_forwarding) != 0); int tlladdr; struct nd_opts ndopts; struct sockaddr_dl *proxydl = NULL; ifp = if_get(m->m_pkthdr.ph_ifidx); if (ifp == NULL) goto freeit; nd_ns = ip6_exthdr_get(&m, off, icmp6len); if (nd_ns == NULL) { icmp6stat_inc(icp6s_tooshort); if_put(ifp); return; } ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */ taddr6 = nd_ns->nd_ns_target; if (ip6->ip6_hlim != 255) goto bad; if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) { /* dst has to be solicited node multicast address. */ /* don't check ifindex portion */ if (daddr6.s6_addr16[0] == __IPV6_ADDR_INT16_MLL && daddr6.s6_addr32[1] == 0 && daddr6.s6_addr32[2] == __IPV6_ADDR_INT32_ONE && daddr6.s6_addr8[12] == 0xff) { ; /*good*/ } else goto bad; } else { /* * Make sure the source address is from a neighbor's address. */ if (!nd6_isneighbor(ifp, &saddr6)) goto bad; } if (IN6_IS_ADDR_MULTICAST(&taddr6)) goto bad; if (IN6_IS_SCOPE_EMBED(&taddr6)) taddr6.s6_addr16[1] = htons(ifp->if_index); icmp6len -= sizeof(*nd_ns); if (nd6_options(nd_ns + 1, icmp6len, &ndopts) < 0) { /* nd6_options have incremented stats */ goto freeit; } if (ndopts.nd_opts_src_lladdr) { lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1); lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3; } if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) goto bad; /* * Attaching target link-layer address to the NA? * (RFC 2461 7.2.4) * * NS IP dst is unicast/anycast MUST NOT add * NS IP dst is solicited-node multicast MUST add * * In implementation, we add target link-layer address by default. * We do not add one in MUST NOT cases. */ #if 0 /* too much! */ ifa = &in6ifa_ifpwithaddr(ifp, &daddr6)->ia_ifa; if (ifa && (ifatoia6(ifa)->ia6_flags & IN6_IFF_ANYCAST)) tlladdr = 0; else #endif if (!IN6_IS_ADDR_MULTICAST(&daddr6)) tlladdr = 0; else tlladdr = 1; /* * Target address (taddr6) must be either: * (1) Valid unicast/anycast address for my receiving interface, * (2) Unicast address for which I'm offering proxy service, or * (3) "tentative" address on which DAD is being performed. */ /* (1) and (3) check. */ ifa = &in6ifa_ifpwithaddr(ifp, &taddr6)->ia_ifa; #if NCARP > 0 if (ifp->if_type == IFT_CARP && ifa && !carp_iamatch(ifp)) ifa = NULL; #endif /* (2) check. */ if (!ifa) { struct rtentry *rt; struct sockaddr_in6 tsin6; bzero(&tsin6, sizeof tsin6); tsin6.sin6_len = sizeof(struct sockaddr_in6); tsin6.sin6_family = AF_INET6; tsin6.sin6_addr = taddr6; rt = rtalloc(sin6tosa(&tsin6), 0, m->m_pkthdr.ph_rtableid); if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 && rt->rt_gateway->sa_family == AF_LINK) { /* * proxy NDP for single entry */ ifa = &in6ifa_ifpforlinklocal(ifp, IN6_IFF_TENTATIVE| IN6_IFF_DUPLICATED|IN6_IFF_ANYCAST)->ia_ifa; if (ifa) { proxy = 1; proxydl = satosdl(rt->rt_gateway); i_am_router = 0; /* XXX */ } } if (rt) rtfree(rt); } if (!ifa) { /* * We've got an NS packet, and we don't have that address * assigned for us. We MUST silently ignore it. * See RFC2461 7.2.3. */ goto freeit; } myaddr6 = *IFA_IN6(ifa); anycast = ifatoia6(ifa)->ia6_flags & IN6_IFF_ANYCAST; tentative = ifatoia6(ifa)->ia6_flags & IN6_IFF_TENTATIVE; if (ifatoia6(ifa)->ia6_flags & IN6_IFF_DUPLICATED) goto freeit; if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) goto bad; if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) { char addr[INET6_ADDRSTRLEN]; log(LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n", inet_ntop(AF_INET6, &saddr6, addr, sizeof(addr))); goto freeit; } /* * We have neighbor solicitation packet, with target address equals to * one of my tentative address. * * src addr how to process? * --- --- * multicast of course, invalid (rejected in ip6_input) * unicast somebody is doing address resolution -> ignore * unspec dup address detection * * The processing is defined in RFC 2462. */ if (tentative) { /* * If source address is unspecified address, it is for * duplicated address detection. * * If not, the packet is for address resolution; * silently ignore it. */ if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) nd6_dad_ns_input(ifa); goto freeit; } /* * If the source address is unspecified address, entries must not * be created or updated. * It looks that sender is performing DAD. Output NA toward * all-node multicast address, to tell the sender that I'm using * the address. * S bit ("solicited") must be zero. */ if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) { saddr6 = in6addr_linklocal_allnodes; saddr6.s6_addr16[1] = htons(ifp->if_index); nd6_na_output(ifp, &saddr6, &taddr6, ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) | (i_am_router ? ND_NA_FLAG_ROUTER : 0), tlladdr, sdltosa(proxydl)); goto freeit; } nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0, i_am_router); nd6_na_output(ifp, &saddr6, &taddr6, ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) | (i_am_router ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED, tlladdr, sdltosa(proxydl)); freeit: m_freem(m); if_put(ifp); return; bad: icmp6stat_inc(icp6s_badns); m_freem(m); if_put(ifp); } /* * Output an Neighbor Solicitation Message. Caller specifies: * - ICMP6 header source IP6 address * - ND6 header target IP6 address * - ND6 header source datalink address * * Based on RFC 2461 * Based on RFC 2462 (duplicated address detection) * * ln - for source address determination * dad - duplicated address detection */ void nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6, const struct in6_addr *taddr6, const struct in6_addr *saddr6, int dad) { struct mbuf *m; struct ip6_hdr *ip6; struct nd_neighbor_solicit *nd_ns; struct sockaddr_in6 src_sa, dst_sa; struct ip6_moptions im6o; int icmp6len; int maxlen; caddr_t mac; if (IN6_IS_ADDR_MULTICAST(taddr6)) return; /* estimate the size of message */ maxlen = sizeof(*ip6) + sizeof(*nd_ns); maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7; #ifdef DIAGNOSTIC if (max_linkhdr + maxlen >= MCLBYTES) { printf("%s: max_linkhdr + maxlen >= MCLBYTES (%d + %d > %d)\n", __func__, max_linkhdr, maxlen, MCLBYTES); panic("%s: insufficient MCLBYTES", __func__); /* NOTREACHED */ } #endif MGETHDR(m, M_DONTWAIT, MT_DATA); if (m && max_linkhdr + maxlen >= MHLEN) { MCLGET(m, M_DONTWAIT); if ((m->m_flags & M_EXT) == 0) { m_free(m); m = NULL; } } if (m == NULL) return; m->m_pkthdr.ph_ifidx = 0; m->m_pkthdr.ph_rtableid = ifp->if_rdomain; if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) { m->m_flags |= M_MCAST; im6o.im6o_ifidx = ifp->if_index; im6o.im6o_hlim = 255; im6o.im6o_loop = 0; } icmp6len = sizeof(*nd_ns); m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len; m_align(m, maxlen); /* fill neighbor solicitation packet */ ip6 = mtod(m, struct ip6_hdr *); ip6->ip6_flow = 0; ip6->ip6_vfc &= ~IPV6_VERSION_MASK; ip6->ip6_vfc |= IPV6_VERSION; /* ip6->ip6_plen will be set later */ ip6->ip6_nxt = IPPROTO_ICMPV6; ip6->ip6_hlim = 255; /* determine the source and destination addresses */ bzero(&src_sa, sizeof(src_sa)); bzero(&dst_sa, sizeof(dst_sa)); src_sa.sin6_family = dst_sa.sin6_family = AF_INET6; src_sa.sin6_len = dst_sa.sin6_len = sizeof(struct sockaddr_in6); if (daddr6 != NULL) dst_sa.sin6_addr = *daddr6; else { dst_sa.sin6_addr.s6_addr16[0] = __IPV6_ADDR_INT16_MLL; dst_sa.sin6_addr.s6_addr16[1] = htons(ifp->if_index); dst_sa.sin6_addr.s6_addr32[1] = 0; dst_sa.sin6_addr.s6_addr32[2] = __IPV6_ADDR_INT32_ONE; dst_sa.sin6_addr.s6_addr32[3] = taddr6->s6_addr32[3]; dst_sa.sin6_addr.s6_addr8[12] = 0xff; } ip6->ip6_dst = dst_sa.sin6_addr; if (!dad) { /* * RFC2461 7.2.2: * "If the source address of the packet prompting the * solicitation is the same as one of the addresses assigned * to the outgoing interface, that address SHOULD be placed * in the IP Source Address of the outgoing solicitation. * Otherwise, any one of the addresses assigned to the * interface should be used." * * We use the source address for the prompting packet * (saddr6), if: * - saddr6 is given from the caller (by giving "ln"), and * - saddr6 belongs to the outgoing interface and * - if taddr is link local saddr6 must be link local as well * Otherwise, we perform the source address selection as usual. */ if (saddr6 != NULL) src_sa.sin6_addr = *saddr6; if (!IN6_IS_ADDR_LINKLOCAL(taddr6) || IN6_IS_ADDR_UNSPECIFIED(&src_sa.sin6_addr) || IN6_IS_ADDR_LINKLOCAL(&src_sa.sin6_addr) || !in6ifa_ifpwithaddr(ifp, &src_sa.sin6_addr)) { struct rtentry *rt; rt = rtalloc(sin6tosa(&dst_sa), RT_RESOLVE, m->m_pkthdr.ph_rtableid); if (!rtisvalid(rt)) { rtfree(rt); goto bad; } src_sa.sin6_addr = ifatoia6(rt->rt_ifa)->ia_addr.sin6_addr; rtfree(rt); } } else { /* * Source address for DAD packet must always be IPv6 * unspecified address. (0::0) * We actually don't have to 0-clear the address (we did it * above), but we do so here explicitly to make the intention * clearer. */ bzero(&src_sa.sin6_addr, sizeof(src_sa.sin6_addr)); } ip6->ip6_src = src_sa.sin6_addr; nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1); nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT; nd_ns->nd_ns_code = 0; nd_ns->nd_ns_reserved = 0; nd_ns->nd_ns_target = *taddr6; if (IN6_IS_SCOPE_EMBED(&nd_ns->nd_ns_target)) nd_ns->nd_ns_target.s6_addr16[1] = 0; /* * Add source link-layer address option. * * spec implementation * --- --- * DAD packet MUST NOT do not add the option * there's no link layer address: * impossible do not add the option * there's link layer address: * Multicast NS MUST add one add the option * Unicast NS SHOULD add one add the option */ if (!dad && (mac = nd6_ifptomac(ifp))) { int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen; struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1); /* 8 byte alignments... */ optlen = (optlen + 7) & ~7; m->m_pkthdr.len += optlen; m->m_len += optlen; icmp6len += optlen; bzero((caddr_t)nd_opt, optlen); nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; nd_opt->nd_opt_len = optlen >> 3; bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen); } ip6->ip6_plen = htons((u_short)icmp6len); nd_ns->nd_ns_cksum = 0; m->m_pkthdr.csum_flags |= M_ICMP_CSUM_OUT; ip6_output(m, NULL, NULL, dad ? IPV6_UNSPECSRC : 0, &im6o, NULL); icmp6stat_inc(icp6s_outhist + ND_NEIGHBOR_SOLICIT); return; bad: m_freem(m); } /* * Neighbor advertisement input handling. * * Based on RFC 2461 * Based on RFC 2462 (duplicated address detection) * * the following items are not implemented yet: * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD) * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD) */ void nd6_na_input(struct mbuf *m, int off, int icmp6len) { struct ifnet *ifp; struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); struct nd_neighbor_advert *nd_na; struct in6_addr daddr6 = ip6->ip6_dst; struct in6_addr taddr6; int flags; int is_router; int is_solicited; int is_override; char *lladdr = NULL; int lladdrlen = 0; int i_am_router = (atomic_load_int(&ip6_forwarding) != 0); struct ifaddr *ifa; struct in6_ifaddr *ifa6; struct llinfo_nd6 *ln; struct rtentry *rt = NULL; struct sockaddr_dl *sdl; struct nd_opts ndopts; NET_ASSERT_LOCKED_EXCLUSIVE(); ifp = if_get(m->m_pkthdr.ph_ifidx); if (ifp == NULL) goto freeit; if (ip6->ip6_hlim != 255) goto bad; nd_na = ip6_exthdr_get(&m, off, icmp6len); if (nd_na == NULL) { icmp6stat_inc(icp6s_tooshort); if_put(ifp); return; } taddr6 = nd_na->nd_na_target; flags = nd_na->nd_na_flags_reserved; is_router = ((flags & ND_NA_FLAG_ROUTER) != 0); is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0); is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0); if (IN6_IS_SCOPE_EMBED(&taddr6)) taddr6.s6_addr16[1] = htons(ifp->if_index); if (IN6_IS_ADDR_MULTICAST(&taddr6)) goto bad; if (is_solicited && IN6_IS_ADDR_MULTICAST(&daddr6)) goto bad; icmp6len -= sizeof(*nd_na); if (nd6_options(nd_na + 1, icmp6len, &ndopts) < 0) { /* nd6_options have incremented stats */ goto freeit; } if (IN6_IS_ADDR_MULTICAST(&daddr6) && !ndopts.nd_opts_tgt_lladdr) goto bad; if (ndopts.nd_opts_tgt_lladdr) { lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1); lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3; } ifa6 = in6ifa_ifpwithaddr(ifp, &taddr6); ifa = ifa6 ? &ifa6->ia_ifa : NULL; /* * Target address matches one of my interface address. * * If my address is tentative, this means that there's somebody * already using the same address as mine. This indicates DAD failure. * This is defined in RFC 2462. * * Otherwise, process as defined in RFC 2461. */ if (ifa && (ifatoia6(ifa)->ia6_flags & IN6_IFF_TENTATIVE)) { struct dadq *dp; dp = nd6_dad_find(ifa); if (dp) { dp->dad_na_icount++; /* remove the address. */ nd6_dad_duplicated(dp); } goto freeit; } if (ifa) { char addr[INET6_ADDRSTRLEN]; #if NCARP > 0 /* * Ignore NAs silently for carp addresses if we're not * the CARP master. */ if (ifp->if_type == IFT_CARP && !carp_iamatch(ifp)) goto freeit; #endif log(LOG_ERR, "nd6_na_input: duplicate IP6 address %s\n", inet_ntop(AF_INET6, &taddr6, addr, sizeof(addr))); goto freeit; } if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) goto bad; /* Check if we already have this neighbor in our cache. */ rt = nd6_lookup(&taddr6, 0, ifp, ifp->if_rdomain); /* * If we are a router, we may create new stale cache entries upon * receiving Unsolicited Neighbor Advertisements. */ if (rt == NULL && i_am_router) { rt = nd6_lookup(&taddr6, 1, ifp, ifp->if_rdomain); if (rt == NULL || lladdr == NULL || ((sdl = satosdl(rt->rt_gateway)) == NULL)) goto freeit; ln = (struct llinfo_nd6 *)rt->rt_llinfo; sdl->sdl_alen = ifp->if_addrlen; bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen); /* * RFC9131 6.1.1 * * Routers SHOULD create a new entry for the target address * with the reachability state set to STALE. */ ln->ln_state = ND6_LLINFO_STALE; nd6_llinfo_settimer(ln, nd6_gctimer); goto freeit; } /* * Host: * If no neighbor cache entry is found, NA SHOULD silently be * discarded. */ if ((rt == NULL) || ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) || ((sdl = satosdl(rt->rt_gateway)) == NULL)) goto freeit; if (ln->ln_state == ND6_LLINFO_INCOMPLETE) { /* * If the link-layer has address, and no lladdr option came, * discard the packet. */ if (ifp->if_addrlen && !lladdr) goto freeit; /* * Record link-layer address, and update the state. */ sdl->sdl_alen = ifp->if_addrlen; bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen); if (is_solicited) { ln->ln_state = ND6_LLINFO_REACHABLE; /* Notify userland that a new ND entry is reachable. */ rtm_send(rt, RTM_RESOLVE, 0, ifp->if_rdomain); if (!ND6_LLINFO_PERMANENT(ln)) { nd6_llinfo_settimer(ln, ifp->if_nd->reachable); } } else { ln->ln_state = ND6_LLINFO_STALE; nd6_llinfo_settimer(ln, nd6_gctimer); } if ((ln->ln_router = is_router) != 0) { /* * This means a router's state has changed from * non-reachable to probably reachable, and might * affect the status of associated prefixes.. */ if ((rt->rt_flags & RTF_LLINFO) == 0) goto freeit; /* ln is gone */ } } else { int llchange; /* * Check if the link-layer address has changed or not. */ if (!lladdr) llchange = 0; else { if (sdl->sdl_alen) { if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen)) llchange = 1; else llchange = 0; } else llchange = 1; } /* * This is VERY complex. Look at it with care. * * override solicit lladdr llchange action * (L: record lladdr) * * 0 0 n -- (2c) * 0 0 y n (2b) L * 0 0 y y (1) REACHABLE->STALE * 0 1 n -- (2c) *->REACHABLE * 0 1 y n (2b) L *->REACHABLE * 0 1 y y (1) REACHABLE->STALE * 1 0 n -- (2a) * 1 0 y n (2a) L * 1 0 y y (2a) L *->STALE * 1 1 n -- (2a) *->REACHABLE * 1 1 y n (2a) L *->REACHABLE * 1 1 y y (2a) L *->REACHABLE */ if (!is_override && (lladdr && llchange)) { /* (1) */ /* * If state is REACHABLE, make it STALE. * no other updates should be done. */ if (ln->ln_state == ND6_LLINFO_REACHABLE) { ln->ln_state = ND6_LLINFO_STALE; nd6_llinfo_settimer(ln, nd6_gctimer); } goto freeit; } else if (is_override /* (2a) */ || (!is_override && (lladdr && !llchange)) /* (2b) */ || !lladdr) { /* (2c) */ /* * Update link-local address, if any. */ if (llchange) { char addr[INET6_ADDRSTRLEN]; log(LOG_INFO, "ndp info overwritten for %s " "by %s on %s\n", inet_ntop(AF_INET6, &taddr6, addr, sizeof(addr)), ether_sprintf(lladdr), ifp->if_xname); } if (lladdr) { sdl->sdl_alen = ifp->if_addrlen; bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen); } /* * If solicited, make the state REACHABLE. * If not solicited and the link-layer address was * changed, make it STALE. */ if (is_solicited) { ln->ln_state = ND6_LLINFO_REACHABLE; if (!ND6_LLINFO_PERMANENT(ln)) { nd6_llinfo_settimer(ln, ifp->if_nd->reachable); } } else { if (lladdr && llchange) { ln->ln_state = ND6_LLINFO_STALE; nd6_llinfo_settimer(ln, nd6_gctimer); } } } if (ln->ln_router && !is_router) { if (!i_am_router) { /* * The neighbor may be used * as a next hop for some destinations * (e.g. redirect case). So we must * call rt6_flush explicitly. */ rt6_flush(&ip6->ip6_src, ifp); } } ln->ln_router = is_router; } rt->rt_flags &= ~RTF_REJECT; ln->ln_asked = 0; if_output_mq(ifp, &ln->ln_mq, &ln_hold_total, rt_key(rt), rt); freeit: rtfree(rt); m_freem(m); if_put(ifp); return; bad: icmp6stat_inc(icp6s_badna); m_freem(m); if_put(ifp); } /* * Neighbor advertisement output handling. * * Based on RFC 2461 * * the following items are not implemented yet: * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD) * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD) * * tlladdr - 1 if include target link-layer address * sdl0 - sockaddr_dl (= proxy NA) or NULL */ void nd6_na_output(struct ifnet *ifp, const struct in6_addr *daddr6, const struct in6_addr *taddr6, u_long flags, int tlladdr, struct sockaddr *sdl0) { struct mbuf *m; struct rtentry *rt = NULL; struct ip6_hdr *ip6; struct nd_neighbor_advert *nd_na; struct ip6_moptions im6o; struct sockaddr_in6 dst_sa; int icmp6len, maxlen; caddr_t mac = NULL; #if NCARP > 0 /* Do not send NAs for carp addresses if we're not the CARP master. */ if (ifp->if_type == IFT_CARP && !carp_iamatch(ifp)) return; #endif /* estimate the size of message */ maxlen = sizeof(*ip6) + sizeof(*nd_na); maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7; #ifdef DIAGNOSTIC if (max_linkhdr + maxlen >= MCLBYTES) { printf("%s: max_linkhdr + maxlen >= MCLBYTES (%d + %d > %d)\n", __func__, max_linkhdr, maxlen, MCLBYTES); panic("%s: insufficient MCLBYTES", __func__); /* NOTREACHED */ } #endif MGETHDR(m, M_DONTWAIT, MT_DATA); if (m && max_linkhdr + maxlen >= MHLEN) { MCLGET(m, M_DONTWAIT); if ((m->m_flags & M_EXT) == 0) { m_free(m); m = NULL; } } if (m == NULL) return; m->m_pkthdr.ph_rtableid = ifp->if_rdomain; if (IN6_IS_ADDR_MULTICAST(daddr6)) { m->m_flags |= M_MCAST; im6o.im6o_ifidx = ifp->if_index; im6o.im6o_hlim = 255; im6o.im6o_loop = 0; } icmp6len = sizeof(*nd_na); m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len; m_align(m, maxlen); /* fill neighbor advertisement packet */ ip6 = mtod(m, struct ip6_hdr *); ip6->ip6_flow = 0; ip6->ip6_vfc &= ~IPV6_VERSION_MASK; ip6->ip6_vfc |= IPV6_VERSION; ip6->ip6_nxt = IPPROTO_ICMPV6; ip6->ip6_hlim = 255; bzero(&dst_sa, sizeof(dst_sa)); dst_sa.sin6_len = sizeof(struct sockaddr_in6); dst_sa.sin6_family = AF_INET6; dst_sa.sin6_addr = *daddr6; if (IN6_IS_ADDR_UNSPECIFIED(daddr6)) { /* reply to DAD */ dst_sa.sin6_addr.s6_addr16[0] = __IPV6_ADDR_INT16_MLL; dst_sa.sin6_addr.s6_addr16[1] = htons(ifp->if_index); dst_sa.sin6_addr.s6_addr32[1] = 0; dst_sa.sin6_addr.s6_addr32[2] = 0; dst_sa.sin6_addr.s6_addr32[3] = __IPV6_ADDR_INT32_ONE; flags &= ~ND_NA_FLAG_SOLICITED; } ip6->ip6_dst = dst_sa.sin6_addr; /* * Select a source whose scope is the same as that of the dest. */ rt = rtalloc(sin6tosa(&dst_sa), RT_RESOLVE, ifp->if_rdomain); if (!rtisvalid(rt)) { rtfree(rt); goto bad; } ip6->ip6_src = ifatoia6(rt->rt_ifa)->ia_addr.sin6_addr; rtfree(rt); nd_na = (struct nd_neighbor_advert *)(ip6 + 1); nd_na->nd_na_type = ND_NEIGHBOR_ADVERT; nd_na->nd_na_code = 0; nd_na->nd_na_target = *taddr6; if (IN6_IS_SCOPE_EMBED(&nd_na->nd_na_target)) nd_na->nd_na_target.s6_addr16[1] = 0; /* * "tlladdr" indicates NS's condition for adding tlladdr or not. * see nd6_ns_input() for details. * Basically, if NS packet is sent to unicast/anycast addr, * target lladdr option SHOULD NOT be included. */ if (tlladdr) { /* * sdl0 != NULL indicates proxy NA. If we do proxy, use * lladdr in sdl0. If we are not proxying (sending NA for * my address) use lladdr configured for the interface. */ if (sdl0 == NULL) { mac = nd6_ifptomac(ifp); } else if (sdl0->sa_family == AF_LINK) { struct sockaddr_dl *sdl; sdl = satosdl(sdl0); if (sdl->sdl_alen == ifp->if_addrlen) mac = LLADDR(sdl); } } if (tlladdr && mac) { int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen; struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1); /* roundup to 8 bytes alignment! */ optlen = (optlen + 7) & ~7; m->m_pkthdr.len += optlen; m->m_len += optlen; icmp6len += optlen; bzero((caddr_t)nd_opt, optlen); nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR; nd_opt->nd_opt_len = optlen >> 3; bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen); } else flags &= ~ND_NA_FLAG_OVERRIDE; ip6->ip6_plen = htons((u_short)icmp6len); nd_na->nd_na_flags_reserved = flags; nd_na->nd_na_cksum = 0; m->m_pkthdr.csum_flags |= M_ICMP_CSUM_OUT; ip6_output(m, NULL, NULL, 0, &im6o, NULL); icmp6stat_inc(icp6s_outhist + ND_NEIGHBOR_ADVERT); return; bad: m_freem(m); } caddr_t nd6_ifptomac(struct ifnet *ifp) { switch (ifp->if_type) { case IFT_ETHER: case IFT_IEEE1394: case IFT_PROPVIRTUAL: case IFT_CARP: case IFT_IEEE80211: return ((caddr_t)(ifp + 1)); default: return NULL; } } struct dadq * nd6_dad_find(struct ifaddr *ifa) { struct dadq *dp; TAILQ_FOREACH(dp, &dadq, dad_list) { if (dp->dad_ifa == ifa) return dp; } return NULL; } void nd6_dad_destroy(struct dadq *dp) { TAILQ_REMOVE(&dadq, dp, dad_list); ip6_dad_pending--; timeout_set_proc(&dp->dad_timer_ch, nd6_dad_reaper, dp); timeout_add(&dp->dad_timer_ch, 0); } void nd6_dad_reaper(void *arg) { struct dadq *dp = arg; ifafree(dp->dad_ifa); free(dp, M_IP6NDP, sizeof(*dp)); } void nd6_dad_starttimer(struct dadq *dp) { timeout_set_proc(&dp->dad_timer_ch, nd6_dad_timer, dp->dad_ifa); timeout_add_msec(&dp->dad_timer_ch, RETRANS_TIMER); } void nd6_dad_stoptimer(struct dadq *dp) { timeout_del(&dp->dad_timer_ch); } /* * Start Duplicated Address Detection (DAD) for specified interface address. */ void nd6_dad_start(struct ifaddr *ifa) { struct in6_ifaddr *ia6 = ifatoia6(ifa); struct dadq *dp; char addr[INET6_ADDRSTRLEN]; int ip6_dad_count_local = atomic_load_int(&ip6_dad_count); NET_ASSERT_LOCKED(); /* * If we don't need DAD, don't do it. * There are several cases: * - DAD is disabled (ip6_dad_count == 0) * - the interface address is anycast */ KASSERT(ia6->ia6_flags & IN6_IFF_TENTATIVE); if ((ia6->ia6_flags & IN6_IFF_ANYCAST) || ip6_dad_count_local == 0) { ia6->ia6_flags &= ~IN6_IFF_TENTATIVE; rtm_addr(RTM_CHGADDRATTR, ifa); return; } /* DAD already in progress */ if (nd6_dad_find(ifa) != NULL) return; dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT | M_ZERO); if (dp == NULL) { log(LOG_ERR, "%s: memory allocation failed for %s(%s)\n", __func__, inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr, addr, sizeof(addr)), ifa->ifa_ifp ? ifa->ifa_ifp->if_xname : "???"); return; } TAILQ_INSERT_TAIL(&dadq, dp, dad_list); ip6_dad_pending++; /* * Send NS packet for DAD, ip6_dad_count times. * Note that we must delay the first transmission, if this is the * first packet to be sent from the interface after interface * (re)initialization. */ dp->dad_ifa = ifaref(ifa); dp->dad_count = ip6_dad_count_local; dp->dad_ns_icount = dp->dad_na_icount = 0; dp->dad_ns_ocount = dp->dad_ns_tcount = 0; nd6_dad_ns_output(dp, ifa); nd6_dad_starttimer(dp); } /* * terminate DAD unconditionally. used for address removals. */ void nd6_dad_stop(struct ifaddr *ifa) { struct dadq *dp; dp = nd6_dad_find(ifa); if (!dp) { /* DAD wasn't started yet */ return; } nd6_dad_stoptimer(dp); nd6_dad_destroy(dp); } void nd6_dad_timer(void *arg) { struct ifaddr *ifa = arg; struct in6_ifaddr *ia6; struct in6_addr daddr6, taddr6; struct ifnet *ifp; struct dadq *dp; char addr[INET6_ADDRSTRLEN]; NET_LOCK(); ia6 = ifatoia6(ifa); taddr6 = ia6->ia_addr.sin6_addr; ifp = ifa->ifa_ifp; dp = nd6_dad_find(ifa); if (dp == NULL) { log(LOG_ERR, "%s: DAD structure not found\n", __func__); goto done; } if (ia6->ia6_flags & IN6_IFF_DUPLICATED) { log(LOG_ERR, "%s: called with duplicated address %s(%s)\n", __func__, inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr, addr, sizeof(addr)), ifa->ifa_ifp ? ifa->ifa_ifp->if_xname : "???"); goto done; } if ((ia6->ia6_flags & IN6_IFF_TENTATIVE) == 0) { log(LOG_ERR, "%s: called with non-tentative address %s(%s)\n", __func__, inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr, addr, sizeof(addr)), ifa->ifa_ifp ? ifa->ifa_ifp->if_xname : "???"); goto done; } /* timeouted with IFF_{RUNNING,UP} check */ if (dp->dad_ns_tcount > dad_maxtry) { nd6_dad_destroy(dp); goto done; } /* Need more checks? */ if (dp->dad_ns_ocount < dp->dad_count) { /* * We have more NS to go. Send NS packet for DAD. */ nd6_dad_ns_output(dp, ifa); nd6_dad_starttimer(dp); } else { /* * We have transmitted sufficient number of DAD packets. */ if (dp->dad_na_icount || dp->dad_ns_icount) { /* dp will be freed in nd6_dad_duplicated() */ nd6_dad_duplicated(dp); } else { /* * We are done with DAD. No NA came, no NS came. */ ia6->ia6_flags &= ~IN6_IFF_TENTATIVE; rtm_addr(RTM_CHGADDRATTR, ifa); daddr6 = in6addr_linklocal_allrouters; daddr6.s6_addr16[1] = htons(ifp->if_index); /* RFC9131 - inform routers about our new address */ nd6_na_output(ifp, &daddr6, &taddr6, 0, 1, NULL); nd6_dad_destroy(dp); } } done: NET_UNLOCK(); } void nd6_dad_duplicated(struct dadq *dp) { struct in6_ifaddr *ia6 = ifatoia6(dp->dad_ifa); char addr[INET6_ADDRSTRLEN]; log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: " "NS in/out=%d/%d, NA in=%d\n", ia6->ia_ifp->if_xname, inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr, addr, sizeof(addr)), dp->dad_ns_icount, dp->dad_ns_ocount, dp->dad_na_icount); ia6->ia6_flags &= ~IN6_IFF_TENTATIVE; ia6->ia6_flags |= IN6_IFF_DUPLICATED; /* We are done with DAD, with duplicated address found. (failure) */ nd6_dad_stoptimer(dp); log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n", ia6->ia_ifp->if_xname, inet_ntop(AF_INET6, &ia6->ia_addr.sin6_addr, addr, sizeof(addr))); log(LOG_ERR, "%s: manual intervention required\n", ia6->ia_ifp->if_xname); rtm_addr(RTM_CHGADDRATTR, dp->dad_ifa); nd6_dad_destroy(dp); } void nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa) { struct in6_ifaddr *ia6 = ifatoia6(ifa); struct ifnet *ifp = ifa->ifa_ifp; dp->dad_ns_tcount++; if ((ifp->if_flags & IFF_UP) == 0) return; if ((ifp->if_flags & IFF_RUNNING) == 0) return; dp->dad_ns_ocount++; nd6_ns_output(ifp, NULL, &ia6->ia_addr.sin6_addr, NULL, 1); } void nd6_dad_ns_input(struct ifaddr *ifa) { struct dadq *dp; if (!ifa) panic("%s: ifa == NULL", __func__); dp = nd6_dad_find(ifa); if (dp == NULL) { log(LOG_ERR, "%s: DAD structure not found\n", __func__); return; } /* * if I'm yet to start DAD, someone else started using this address * first. I have a duplicate and you win. */ /* XXX more checks for loopback situation - see nd6_dad_timer too */ if (dp->dad_ns_ocount == 0) { /* dp will be freed in nd6_dad_duplicated() */ nd6_dad_duplicated(dp); } else { /* * not sure if I got a duplicate. * increment ns count and see what happens. */ dp->dad_ns_icount++; } } /* * Check whether ``addr'' is a neighbor address connected to ``ifp''. */ int nd6_isneighbor(const struct ifnet *ifp, const struct in6_addr *addr) { struct rtentry *rt; struct sockaddr_in6 sin6; unsigned int tableid = ifp->if_rdomain; int rv = 0; memset(&sin6, 0, sizeof(sin6)); sin6.sin6_len = sizeof(struct sockaddr_in6); sin6.sin6_family = AF_INET6; sin6.sin6_addr = *addr; rt = rtalloc(sin6tosa(&sin6), 0, tableid); if (rtisvalid(rt) && ISSET(rt->rt_flags, RTF_CLONING|RTF_CLONED)) rv = if_isconnected(ifp, rt->rt_ifidx); rtfree(rt); return (rv); }