bring in KAME IPv6 code, dated 19991208.

replaces NRL IPv6 layer.  reuses NRL pcb layer.  no IPsec-on-v6 support.
see sys/netinet6/{TODO,IMPLEMENTATION} for more details.

GENERIC configuration should work fine as before.  GENERIC.v6 works fine
as well, but you'll need KAME userland tools to play with IPv6 (will be
bringed into soon).

1 files changed, 1261 insertions, 0 deletions

diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c
new file mode 100644
index 00000000000..274a7d63c1c
--- /dev/null
+++ b/sys/netinet6/nd6_nbr.c
@@ -0,0 +1,1261 @@
+/*	$OpenBSD: nd6_nbr.c,v 1.1 1999/12/08 06:50:23 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.
+ */
+
+#if (defined(__FreeBSD__) && __FreeBSD__ >= 3) || defined(__NetBSD__)
+#include "opt_inet.h"
+#ifdef __NetBSD__	/*XXX*/
+#include "opt_ipsec.h"
+#endif
+#endif
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/sockio.h>
+#include <sys/time.h>
+#include <sys/kernel.h>
+#include <sys/errno.h>
+#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
+#include <sys/ioctl.h>
+#endif 
+#include <sys/syslog.h>
+#include <sys/queue.h>
+
+#include <net/if.h>
+#include <net/if_types.h>
+#include <net/if_dl.h>
+#include <net/route.h>
+
+#include <netinet/in.h>
+#include <netinet/in_var.h>
+#include <netinet6/in6_var.h>
+#include <netinet6/ip6.h>
+#include <netinet6/ip6_var.h>
+#include <netinet6/nd6.h>
+#include <netinet6/icmp6.h>
+
+#include <net/net_osdep.h>
+
+#define SDL(s) ((struct sockaddr_dl *)s)
+
+#if 0
+extern	struct timeval time;
+#endif
+
+struct dadq;
+static struct dadq *nd6_dad_find __P((struct ifaddr *));
+static void nd6_dad_timer __P((struct ifaddr *));
+static void nd6_dad_ns_output __P((struct dadq *, struct ifaddr *));
+static void nd6_dad_ns_input __P((struct ifaddr *));
+static void nd6_dad_na_input __P((struct ifaddr *));
+
+static int dad_ignore_ns = 0;	/* ignore NS in DAD - specwise incorrect*/
+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)
+ *
+ * XXX proxy advertisement
+ */
+void
+nd6_ns_input(m, off, icmp6len)
+	struct mbuf *m;
+	int off, icmp6len;
+{
+	struct ifnet *ifp = m->m_pkthdr.rcvif;
+	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
+	struct nd_neighbor_solicit *nd_ns
+		= (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
+	struct in6_addr saddr6 = ip6->ip6_src;
+	struct in6_addr daddr6 = ip6->ip6_dst;
+	struct in6_addr taddr6 = nd_ns->nd_ns_target;
+	struct in6_addr myaddr6;
+	char *lladdr = NULL;
+	struct ifaddr *ifa;
+	int lladdrlen = 0;
+	int anycast = 0, proxy = 0, tentative = 0;
+	int tlladdr;
+	union nd_opts ndopts;
+
+	if (ip6->ip6_hlim != 255) {
+		log(LOG_ERR,
+		    "nd6_ns_input: invalid hlim %d\n", ip6->ip6_hlim);
+		return;
+	}
+
+	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
+		/* dst has to be solicited node multicast address. */
+		if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL
+		    /*don't check ifindex portion*/
+		    && daddr6.s6_addr32[1] == 0
+		    && daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE
+		    && daddr6.s6_addr8[12] == 0xff) {
+			; /*good*/
+		} else {
+			log(LOG_INFO, "nd6_ns_input: bad DAD packet "
+				"(wrong ip6 dst)\n");
+			goto bad;
+		}
+	}
+
+	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
+		log(LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n");
+		goto bad;
+	}
+
+	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
+		taddr6.s6_addr16[1] = htons(ifp->if_index);
+
+	icmp6len -= sizeof(*nd_ns);
+	nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
+	if (nd6_options(&ndopts) < 0) {
+		log(LOG_INFO, "nd6_ns_input: invalid ND option, ignored\n");
+		goto bad;
+	}
+
+	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) {
+		log(LOG_INFO, "nd6_ns_input: bad DAD packet "
+			"(link-layer address option)\n");
+		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 = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
+	if (ifa && (((struct in6_ifaddr *)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 = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
+
+	/* (2) check. */
+	if (!ifa && nd6_proxyall) {
+		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 = rtalloc1((struct sockaddr *)&tsin6, 0
+#ifdef __FreeBSD__
+			      , 0
+#endif /* __FreeBSD__ */
+			      );
+		if (rt && rt->rt_ifp != ifp) {
+			/*
+			 * search link local addr for ifp, and use it for
+			 * proxy NA.
+			 */
+			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp);
+			if (ifa)
+				proxy = 1;
+		}
+		rtfree(rt);
+	}
+	if (!ifa) {
+		/*
+		 * We've got a NS packet, and we don't have that adddress
+		 * assigned for us.  We MUST silently ignore it.
+		 * See RFC2461 7.2.3.
+		 */
+		return;
+	}
+	myaddr6 = *IFA_IN6(ifa);
+	anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
+	tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
+	if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
+		return;
+
+	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
+		log(LOG_INFO,
+		    "nd6_ns_input: lladdrlen mismatch for %s "
+		    "(if %d, NS packet %d)\n",
+			ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2);
+	}
+
+	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
+		log(LOG_INFO,
+		    "nd6_ns_input: duplicate IP6 address %s\n",
+		    ip6_sprintf(&saddr6));
+		return;
+	}
+
+	/*
+	 * 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 addess resolution;
+		 * silently ignore it.
+		 */
+		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
+			nd6_dad_ns_input(ifa);
+
+		return;
+	}
+
+	/*
+	 * 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)
+			      	| (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
+			      tlladdr);
+		return;
+	}
+
+	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0);
+
+	nd6_na_output(ifp, &saddr6, &taddr6,
+		      ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE)
+			| (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0)
+			| ND_NA_FLAG_SOLICITED,
+		      tlladdr);
+	return;
+
+ bad:
+	log(LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6));
+	log(LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6));
+	log(LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6));
+	return;
+}
+
+/*
+ * 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)
+ */
+void
+nd6_ns_output(ifp, daddr6, taddr6, ln, dad)
+	struct ifnet *ifp;
+	struct in6_addr *daddr6, *taddr6;
+	struct llinfo_nd6 *ln;	/* for source address determination */
+	int dad;	/* duplicated address detection */
+{
+	struct mbuf *m;
+	struct ip6_hdr *ip6;
+	struct nd_neighbor_solicit *nd_ns;
+	struct in6_ifaddr *ia = NULL;
+	struct ip6_moptions im6o;
+	int icmp6len;
+	caddr_t mac;
+	struct ifnet *outif = NULL;
+	
+	if (IN6_IS_ADDR_MULTICAST(taddr6))
+		return;
+
+	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
+		return;
+
+	if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
+		m->m_flags |= M_MCAST;
+		im6o.im6o_multicast_ifp = ifp;
+		im6o.im6o_multicast_hlim = 255;
+		im6o.im6o_multicast_loop = 0;
+	}
+
+	icmp6len = sizeof(*nd_ns);
+	m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
+	MH_ALIGN(m, m->m_len + 16); /* 1+1+6 is enought. but just in case */
+
+	/* fill neighbor solicitation packet */
+	ip6 = mtod(m, struct ip6_hdr *);
+	ip6->ip6_flow = 0;
+	ip6->ip6_vfc = IPV6_VERSION;
+	/* ip6->ip6_plen will be set later */
+	ip6->ip6_nxt = IPPROTO_ICMPV6;
+	ip6->ip6_hlim = 255;
+	if (daddr6)
+		ip6->ip6_dst = *daddr6;
+	else {
+		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
+		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
+		ip6->ip6_dst.s6_addr32[1] = 0;
+		ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
+		ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
+		ip6->ip6_dst.s6_addr8[12] = 0xff;
+	}
+	if (!dad) {
+#if 0	/* KAME way, exact address scope match */
+		/*
+		 * Select a source whose scope is the same as that of the dest.
+		 * Typically, the dest is link-local solicitation multicast
+		 * (i.e. neighbor discovery) or link-local/global unicast
+		 * (i.e. neighbor un-reachability detection).
+		 */
+		ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
+		if (ia == NULL) {
+			m_freem(m);
+			return;
+		}
+		ip6->ip6_src = ia->ia_addr.sin6_addr;
+#else	/* spec-wise correct */
+		/*
+		 * 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.
+		 * Otherwise, we perform a scope-wise match.
+		 */
+		struct ip6_hdr *hip6;		/*hold ip6*/
+		struct in6_addr *saddr6;
+
+		if (ln && ln->ln_hold) {
+			hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
+			/* XXX pullup? */
+			if (sizeof(*hip6) < ln->ln_hold->m_len)
+				saddr6 = &hip6->ip6_src;
+			else
+				saddr6 = NULL;
+		} else
+			saddr6 = NULL;
+		if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
+			bcopy(saddr6, &ip6->ip6_src, sizeof(*saddr6));
+		else {
+			ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
+			if (ia == NULL) {
+				m_freem(m);	/*XXX*/
+				return;
+			}
+			ip6->ip6_src = ia->ia_addr.sin6_addr;
+		}
+#endif
+	} else {
+		/*
+		 * Source address for DAD packet must always be IPv6
+		 * unspecified address. (0::0)
+		 */
+		bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
+	}
+	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_LINKLOCAL(&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;
+	nd_ns->nd_ns_cksum
+		= in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
+
+#ifdef IPSEC
+#ifndef __OpenBSD__ /*KAME IPSEC*/
+	m->m_pkthdr.rcvif = NULL;
+#endif
+#endif /*IPSEC*/
+	ip6_output(m, NULL, NULL, dad ? IPV6_DADOUTPUT : 0, &im6o, &outif);
+	if (outif) {
+		icmp6_ifstat_inc(outif, ifs6_out_msg);
+		icmp6_ifstat_inc(outif, ifs6_out_neighborsolicit);
+	}
+	icmp6stat.icp6s_outhist[ND_NEIGHBOR_SOLICIT]++;
+}
+
+/*
+ * Neighbor advertisement input handling.
+ *
+ * Based on RFC 2461
+ * Based on RFC 2462 (duplicated address detection)
+ */
+void
+nd6_na_input(m, off, icmp6len)
+	struct mbuf *m;
+	int off, icmp6len;
+{
+	struct ifnet *ifp = m->m_pkthdr.rcvif;
+	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
+	struct nd_neighbor_advert *nd_na
+		= (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
+#if 0
+	struct in6_addr saddr6 = ip6->ip6_src;
+#endif
+	struct in6_addr daddr6 = ip6->ip6_dst;
+	struct in6_addr taddr6 = nd_na->nd_na_target;
+	int flags = nd_na->nd_na_flags_reserved;
+	int is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
+	int is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
+	int is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
+	char *lladdr = NULL;
+	int lladdrlen = 0;
+	struct ifaddr *ifa;
+	struct llinfo_nd6 *ln;
+	struct rtentry *rt;
+	struct sockaddr_dl *sdl;
+	union nd_opts ndopts;
+
+	if (ip6->ip6_hlim != 255) {
+		log(LOG_ERR,
+		    "nd6_na_input: invalid hlim %d\n", ip6->ip6_hlim);
+		return;
+	}
+
+	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
+		taddr6.s6_addr16[1] = htons(ifp->if_index);
+
+	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
+		log(LOG_ERR,
+		    "nd6_na_input: invalid target address %s\n",
+		    ip6_sprintf(&taddr6));
+		return;
+	}
+	if (IN6_IS_ADDR_MULTICAST(&daddr6))
+		if (is_solicited) {
+			log(LOG_ERR,
+			    "nd6_na_input: a solicited adv is multicasted\n");
+			return;
+		}
+
+	icmp6len -= sizeof(*nd_na);
+	nd6_option_init(nd_na + 1, icmp6len, &ndopts);
+	if (nd6_options(&ndopts) < 0) {
+		log(LOG_INFO, "nd6_na_input: invalid ND option, ignored\n");
+		return;
+	}
+
+	if (ndopts.nd_opts_tgt_lladdr) {
+		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
+		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
+	}
+
+	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
+
+	/*
+	 * 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
+	 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
+		nd6_dad_na_input(ifa);
+		return;
+	}
+
+	/* Just for safety, maybe unnecessery. */
+	if (ifa) {
+		log(LOG_ERR,
+		    "nd6_na_input: duplicate IP6 address %s\n",
+		    ip6_sprintf(&taddr6));
+		return;
+	}
+
+	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
+		log(LOG_INFO,
+		    "nd6_na_input: lladdrlen mismatch for %s "
+		    "(if %d, NA packet %d)\n",
+			ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2);
+	}
+
+	/*
+	 * If no neighbor cache entry is found, NA SHOULD silently be discarded.
+	 */
+	rt = nd6_lookup(&taddr6, 0, ifp);
+	if ((rt == NULL) ||
+	   ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
+	   ((sdl = SDL(rt->rt_gateway)) == NULL))
+		return;
+
+	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)
+			return;
+
+		/*
+		 * 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;
+			if (ln->ln_expire)
+#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
+				ln->ln_expire = time.tv_sec +
+#else
+				ln->ln_expire = time_second +
+#endif
+					nd_ifinfo[rt->rt_ifp->if_index].reachable;
+		} else
+			ln->ln_state = ND6_LLINFO_STALE;
+		ln->ln_router = is_router;
+	} 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;
+			return;
+		} else if (is_override				   /* (2a) */
+			|| (!is_override && (lladdr && !llchange)) /* (2b) */
+			|| !lladdr) {				   /* (2c) */
+			/*
+			 * Update link-local address, if any.
+			 */
+			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 (ln->ln_expire) {
+#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
+					ln->ln_expire = time.tv_sec +
+#else
+					ln->ln_expire = time_second +
+#endif
+						nd_ifinfo[ifp->if_index].reachable;
+				}
+			} else {
+				if (lladdr && llchange)
+					ln->ln_state = ND6_LLINFO_STALE;
+			}
+		}
+
+		if (ln->ln_router && !is_router) {
+			/*
+			 * The peer dropped the router flag.
+			 * Remove the sender from the Default Router List and
+			 * update the Destination Cache entries.
+			 */
+			struct nd_defrouter *dr;
+			struct in6_addr *in6;
+			int s;
+
+			in6 = &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr;
+#ifdef __NetBSD__
+			s = splsoftnet();
+#else
+			s = splnet();
+#endif
+			dr = defrouter_lookup(in6, rt->rt_ifp);
+			if (dr)
+				defrtrlist_del(dr);
+			else if (!ip6_forwarding && ip6_accept_rtadv) {
+				/*
+				 * Even if the neighbor is not in the default
+				 * router list, 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, rt->rt_ifp);
+			}
+			splx(s);
+		}
+		ln->ln_router = is_router;
+	}
+	rt->rt_flags &= ~RTF_REJECT;
+	ln->ln_asked = 0;
+	if (ln->ln_hold) {
+#ifdef OLDIP6OUTPUT
+		(*ifp->if_output)(ifp, ln->ln_hold, rt_key(rt), rt);
+#else
+		nd6_output(ifp, ln->ln_hold,
+			   (struct sockaddr_in6 *)rt_key(rt), rt);
+#endif 
+		ln->ln_hold = 0;
+	}
+}
+
+/*
+ * Neighbor advertisement output handling.
+ *
+ * Based on RFC 2461
+ *
+ * XXX NA delay for anycast address is not implemented yet
+ *      (RFC 2461 7.2.7)
+ * XXX proxy advertisement?
+ */
+void
+nd6_na_output(ifp, daddr6, taddr6, flags, tlladdr)
+	struct ifnet *ifp;
+	struct in6_addr *daddr6, *taddr6;
+	u_long flags;
+	int tlladdr;	/* 1 if include target link-layer address */
+{
+	struct mbuf *m;
+	struct ip6_hdr *ip6;
+	struct nd_neighbor_advert *nd_na;
+	struct in6_ifaddr *ia = NULL;
+	struct ip6_moptions im6o;
+	int icmp6len;
+	caddr_t mac;
+	struct ifnet *outif = NULL;
+	
+	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
+		return;
+
+	if (IN6_IS_ADDR_MULTICAST(daddr6)) {
+		m->m_flags |= M_MCAST;
+		im6o.im6o_multicast_ifp = ifp;
+		im6o.im6o_multicast_hlim = 255;
+		im6o.im6o_multicast_loop = 0;
+	}
+
+	icmp6len = sizeof(*nd_na);
+	m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
+	MH_ALIGN(m, m->m_len + 16); /* 1+1+6 is enough. but just in case */
+
+	/* fill neighbor advertisement packet */
+	ip6 = mtod(m, struct ip6_hdr *);
+	ip6->ip6_flow = 0;
+	ip6->ip6_vfc = IPV6_VERSION;
+	ip6->ip6_nxt = IPPROTO_ICMPV6;
+	ip6->ip6_hlim = 255;
+	if (IN6_IS_ADDR_UNSPECIFIED(daddr6)) {
+		/* reply to DAD */
+		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
+		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
+		ip6->ip6_dst.s6_addr32[1] = 0;
+		ip6->ip6_dst.s6_addr32[2] = 0;
+		ip6->ip6_dst.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
+		flags &= ~ND_NA_FLAG_SOLICITED;
+	} else
+		ip6->ip6_dst = *daddr6;
+
+	/*
+	 * Select a source whose scope is the same as that of the dest.
+	 */
+	ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
+	if (ia == NULL) {
+		m_freem(m);
+		return;
+	}
+	ip6->ip6_src = ia->ia_addr.sin6_addr;
+	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_LINKLOCAL(&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 && (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_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;
+	nd_na->nd_na_cksum =
+		in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
+
+#ifdef IPSEC
+#ifndef __OpenBSD__ /*KAME IPSEC*/
+	m->m_pkthdr.rcvif = NULL;
+#endif
+#endif /*IPSEC*/
+	ip6_output(m, NULL, NULL, 0, &im6o, &outif);
+	if (outif) {
+		icmp6_ifstat_inc(outif, ifs6_out_msg);
+		icmp6_ifstat_inc(outif, ifs6_out_neighboradvert);
+	}
+	icmp6stat.icp6s_outhist[ND_NEIGHBOR_ADVERT]++;
+}
+
+caddr_t
+nd6_ifptomac(ifp)
+	struct ifnet *ifp;
+{
+	switch (ifp->if_type) {
+	case IFT_ARCNET:
+	case IFT_ETHER:
+	case IFT_FDDI:
+#ifdef __NetBSD__
+		return LLADDR(ifp->if_sadl);
+#else
+		return ((caddr_t)(ifp + 1));
+#endif
+		break;
+	default:
+		return NULL;
+	}
+}
+
+TAILQ_HEAD(dadq_head, dadq);
+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;
+#if defined(__FreeBSD__) && __FreeBSD__ >= 3
+	struct callout_handle dad_timer;
+#endif
+};
+
+static struct dadq_head dadq;
+
+static struct dadq *
+nd6_dad_find(ifa)
+	struct ifaddr *ifa;
+{
+	struct dadq *dp;
+
+	for (dp = dadq.tqh_first; dp; dp = dp->dad_list.tqe_next) {
+		if (dp->dad_ifa == ifa)
+			return dp;
+	}
+	return NULL;
+}
+
+/*
+ * Start Duplicated Address Detection (DAD) for specified interface address.
+ */
+void
+nd6_dad_start(ifa, tick)
+	struct ifaddr *ifa;
+	int *tick;	/* minimum delay ticks for IFF_UP event */
+{
+	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
+	struct dadq *dp;
+	static int dad_init = 0;
+
+	if (!dad_init) {
+		TAILQ_INIT(&dadq);
+		dad_init++;
+	}
+
+	/*
+	 * 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
+	 */
+	if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
+		printf("nd6_dad_start: called with non-tentative address "
+			"%s(%s)\n",
+			ip6_sprintf(&ia->ia_addr.sin6_addr),
+			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
+		return;
+	}
+	if (ia->ia6_flags & IN6_IFF_ANYCAST) {
+		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
+		return;
+	}
+	if (!ip6_dad_count) {
+		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
+		return;
+	}
+	if (!ifa->ifa_ifp)
+		panic("nd6_dad_start: ifa->ifa_ifp == NULL");
+	if (!(ifa->ifa_ifp->if_flags & IFF_UP))
+		return;
+	if (nd6_dad_find(ifa) != NULL) {
+		/* DAD already in progress */
+		return;
+	}
+
+	dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
+	if (dp == NULL) {
+		printf("nd6_dad_start: memory allocation failed for "
+			"%s(%s)\n",
+			ip6_sprintf(&ia->ia_addr.sin6_addr),
+			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
+		return;
+	}
+	bzero(dp, sizeof(*dp));
+	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
+
+	/* XXXJRT This is probably a purely debugging message. */
+	printf("%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
+	    ip6_sprintf(&ia->ia_addr.sin6_addr));
+
+	/*
+	 * 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 = ifa;
+	ifa->ifa_refcnt++;	/*just for safety*/
+	dp->dad_count = ip6_dad_count;
+	dp->dad_ns_icount = dp->dad_na_icount = 0;
+	dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
+	if (!tick) {
+		nd6_dad_ns_output(dp, ifa);
+#if defined(__FreeBSD__) && __FreeBSD__ >= 3
+		dp->dad_timer =
+#endif
+		timeout((void (*) __P((void *)))nd6_dad_timer, (void *)ifa,
+			nd_ifinfo[ifa->ifa_ifp->if_index].retrans * hz / 1000);
+	} else {
+		int ntick;
+
+		if (*tick == 0)
+			ntick = random() % (MAX_RTR_SOLICITATION_DELAY * hz);
+		else
+			ntick = *tick + random() % (hz / 2);
+		*tick = ntick;
+#if defined(__FreeBSD__) && __FreeBSD__ >= 3
+		dp->dad_timer =
+#endif
+		timeout((void (*) __P((void *)))nd6_dad_timer, (void *)ifa,
+			ntick);
+	}
+}
+
+static void
+nd6_dad_timer(ifa)
+	struct ifaddr *ifa;
+{
+	int s;
+	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
+	struct dadq *dp;
+
+#ifdef __NetBSD__
+	s = splsoftnet();	/*XXX*/
+#else
+	s = splnet();		/*XXX*/
+#endif
+
+	/* Sanity check */
+	if (ia == NULL) {
+		printf("nd6_dad_timer: called with null parameter\n");
+		goto done;
+	}
+	dp = nd6_dad_find(ifa);
+	if (dp == NULL) {
+		printf("nd6_dad_timer: DAD structure not found\n");
+		goto done;
+	}
+	if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
+		printf("nd6_dad_timer: called with duplicated address "
+			"%s(%s)\n",
+			ip6_sprintf(&ia->ia_addr.sin6_addr),
+			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
+		goto done;
+	}
+	if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
+		printf("nd6_dad_timer: called with non-tentative address "
+			"%s(%s)\n",
+			ip6_sprintf(&ia->ia_addr.sin6_addr),
+			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
+		goto done;
+	}
+
+	/* timeouted with IFF_{RUNNING,UP} check */
+	if (dp->dad_ns_tcount > dad_maxtry) {
+		printf("%s: could not run DAD, driver problem?\n",
+		    if_name(ifa->ifa_ifp));
+
+		TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
+		free(dp, M_IP6NDP);
+		dp = NULL;
+		ifa->ifa_refcnt--;
+		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);
+#if defined(__FreeBSD__) && __FreeBSD__ >= 3
+		dp->dad_timer =
+#endif
+		timeout((void (*) __P((void *)))nd6_dad_timer, (void *)ifa,
+			nd_ifinfo[ifa->ifa_ifp->if_index].retrans * hz / 1000);
+	} else {
+		/*
+		 * We have transmitted sufficient number of DAD packets.
+		 * See what we've got.
+		 */
+		int duplicate;
+
+		duplicate = 0;
+
+		if (dp->dad_na_icount) {
+			/*
+			 * the check is in nd6_dad_na_input(),
+			 * but just in case
+			 */
+			duplicate++;
+		}
+
+		if (dp->dad_ns_icount) {
+#if 0 /*heuristics*/
+			/*
+			 * if
+			 * - we have sent many(?) DAD NS, and
+			 * - the number of NS we sent equals to the
+			 *   number of NS we've got, and
+			 * - we've got no NA
+			 * we may have a faulty network card/driver which
+			 * loops back multicasts to myself.
+			 */
+			if (3 < dp->dad_count
+			 && dp->dad_ns_icount == dp->dad_count
+			 && dp->dad_na_icount == 0) {
+				log(LOG_INFO, "DAD questionable for %s(%s): "
+					"network card loops back multicast?\n",
+					ip6_sprintf(&ia->ia_addr.sin6_addr),
+					if_name(ifa->ifa_ifp));
+				/* XXX consider it a duplicate or not? */
+				/* duplicate++; */
+			} else {
+				/* We've seen NS, means DAD has failed. */
+				duplicate++;
+			}
+#else
+			/* We've seen NS, means DAD has failed. */
+			duplicate++;
+#endif
+		}
+
+		if (duplicate) {
+			/* (*dp) will be freed in nd6_dad_duplicated() */
+			dp = NULL;
+			nd6_dad_duplicated(ifa);
+		} else {
+			/*
+			 * We are done with DAD.  No NA came, no NS came.
+			 * duplicated address found.
+			 */
+			ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
+
+			/* XXXJRT This is probably a purely debugging message */
+			printf("%s: DAD complete for %s - no duplicates "
+			    "found\n", if_name(ifa->ifa_ifp),
+			    ip6_sprintf(&ia->ia_addr.sin6_addr));
+
+			TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
+			free(dp, M_IP6NDP);
+			dp = NULL;
+			ifa->ifa_refcnt--;
+		}
+	}
+
+done:
+	splx(s);
+}
+
+void
+nd6_dad_duplicated(ifa)
+	struct ifaddr *ifa;
+{
+	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
+	struct dadq *dp;
+
+	dp = nd6_dad_find(ifa);
+	if (dp == NULL) {
+		printf("nd6_dad_duplicated: DAD structure not found\n");
+		return;
+	}
+
+	log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: %d NS, "
+	    "%d NA\n", if_name(ifa->ifa_ifp),
+	    ip6_sprintf(&ia->ia_addr.sin6_addr),
+	    dp->dad_ns_icount, dp->dad_na_icount);
+
+	ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
+	ia->ia6_flags |= IN6_IFF_DUPLICATED;
+
+	/* We are done with DAD, with duplicated address found. (failure) */
+	untimeout((void (*) __P((void *)))nd6_dad_timer, (void *)ifa
+#if defined(__FreeBSD__) && __FreeBSD__ >= 3
+		, dp->dad_timer
+#endif
+		);
+
+	printf("%s: DAD complete for %s - duplicate found\n",
+	    if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr));
+	printf("%s: manual intervention required\n", if_name(ifa->ifa_ifp));
+
+	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
+	free(dp, M_IP6NDP);
+	dp = NULL;
+	ifa->ifa_refcnt--;
+}
+
+static void
+nd6_dad_ns_output(dp, ifa)
+	struct dadq *dp;
+	struct ifaddr *ifa;
+{
+	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
+	struct ifnet *ifp = ifa->ifa_ifp;
+
+	dp->dad_ns_tcount++;
+	if ((ifp->if_flags & IFF_UP) == 0) {
+#if 0
+		printf("%s: interface down?\n", if_name(ifp));
+#endif
+		return;
+	}
+	if ((ifp->if_flags & IFF_RUNNING) == 0) {
+#if 0
+		printf("%s: interface not running?\n", if_name(ifp));
+#endif
+		return;
+	}
+
+	dp->dad_ns_ocount++;
+	nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
+}
+
+static void
+nd6_dad_ns_input(ifa)
+	struct ifaddr *ifa;
+{
+	struct in6_ifaddr *ia;
+	struct ifnet *ifp;
+	struct in6_addr *taddr6;
+	struct dadq *dp;
+	int duplicate;
+
+	if (!ifa)
+		panic("ifa == NULL in nd6_dad_ns_input");
+
+	ia = (struct in6_ifaddr *)ifa;
+	ifp = ifa->ifa_ifp;
+	taddr6 = &ia->ia_addr.sin6_addr;
+	duplicate = 0;
+	dp = nd6_dad_find(ifa);
+
+	/*
+	 * If it is from myself, ignore this.
+	 */
+	if (ifp && (ifp->if_flags & IFF_LOOPBACK))
+		return;
+
+	/* Quickhack - completely ignore DAD NS packets */
+	if (dad_ignore_ns) {
+		log(LOG_INFO, "nd6_dad_ns_input: ignoring DAD NS packet for "
+		    "address %s(%s)\n", ip6_sprintf(taddr6),
+		    if_name(ifa->ifa_ifp));
+		return;
+	}
+
+	/*
+	 * if I'm yet to start DAD, someone else started using this address
+	 * first.  I have a duplicate and you win.
+	 */
+	if (!dp || dp->dad_ns_ocount == 0)
+		duplicate++;
+
+	/* XXX more checks for loopback situation - see nd6_dad_timer too */
+
+	if (duplicate) {
+		dp = NULL;	/* will be freed in nd6_dad_duplicated() */
+		nd6_dad_duplicated(ifa);
+	} else {
+		/*
+		 * not sure if I got a duplicate.
+		 * increment ns count and see what happens.
+		 */
+		if (dp)
+			dp->dad_ns_icount++;
+	}
+}
+
+static void
+nd6_dad_na_input(ifa)
+	struct ifaddr *ifa;
+{
+	struct dadq *dp;
+
+	if (!ifa)
+		panic("ifa == NULL in nd6_dad_na_input");
+
+	dp = nd6_dad_find(ifa);
+	if (dp)
+		dp->dad_na_icount++;
+
+	/* remove the address. */
+	nd6_dad_duplicated(ifa);
+}