 @@ -1,1533 +1,1533 @@
-/*	$NetBSD: nd6_nbr.c,v 1.166.2.4 2019/09/30 15:55:40 martin Exp $	*/
+/*	$NetBSD: nd6_nbr.c,v 1.166.2.5 2020/04/23 13:31:43 martin 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/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.166.2.4 2019/09/30 15:55:40 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.166.2.5 2020/04/23 13:31:43 martin Exp $");
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
 #include "opt_net_mpsafe.h"
 #endif
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kmem.h>
 #include <sys/mbuf.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/sockio.h>
 #include <sys/time.h>
 #include <sys/kernel.h>
 #include <sys/errno.h>
 #include <sys/ioctl.h>
 #include <sys/syslog.h>
 #include <sys/queue.h>
 #include <sys/callout.h>
 #include <sys/cprng.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/in6_ifattach.h>
 #include <netinet/ip6.h>
 #include <netinet6/ip6_var.h>
 #include <netinet6/scope6_var.h>
 #include <netinet6/nd6.h>
 #include <netinet/icmp6.h>
 #include <netinet6/icmp6_private.h>
 #include "carp.h"
 #if NCARP > 0
 #include <netinet/ip_carp.h>
 #endif
 struct dadq;
 static struct dadq *nd6_dad_find(struct ifaddr *, struct nd_opt_nonce *, bool *);
 static bool nd6_dad_ownnonce(struct ifaddr *, struct nd_opt_nonce *nonce);
 static void nd6_dad_starttimer(struct dadq *, int);
 static void nd6_dad_destroytimer(struct dadq *);
 static void nd6_dad_timer(struct dadq *);
 static void nd6_dad_ns_output(struct dadq *, struct ifaddr *);
 static void nd6_dad_input(struct ifaddr *, struct nd_opt_nonce *,
     const struct sockaddr_dl *);
 static void nd6_dad_duplicated(struct ifaddr *, struct dadq *,
     const struct sockaddr_dl *);
 static int dad_maxtry = 15;	/* max # of *tries* to transmit DAD packet */
 /*
  * Input a Neighbor Solicitation Message.
+ *
  * Based on RFC 2461
  * Based on RFC 2462 (duplicate 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 router = ip6_forwarding;
 	int tlladdr;
 	union nd_opts ndopts;
 	const struct sockaddr_dl *proxydl = NULL;
 	struct psref psref;
 	struct psref psref_ia;
 	char ip6buf[INET6_ADDRSTRLEN], ip6buf2[INET6_ADDRSTRLEN];
 	ifp = m_get_rcvif_psref(m, &psref);
 	if (ifp == NULL)
 		goto freeit;
 	IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
 	if (nd_ns == NULL) {
 		ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
 		m_put_rcvif_psref(ifp, &psref);
 		return;
+	}
 	ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
 	taddr6 = nd_ns->nd_ns_target;
 	if (in6_setscope(&taddr6, ifp, NULL) != 0)
 		goto bad;
 	if (ip6->ip6_hlim != 255) {
 		nd6log(LOG_ERR, "invalid hlim (%d) from %s to %s on %s\n",
 		    ip6->ip6_hlim, IN6_PRINT(ip6buf, &ip6->ip6_src),
 		    IN6_PRINT(ip6buf2, &ip6->ip6_dst), if_name(ifp));
 		goto bad;
+	}
 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
 		/* dst has to be a 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 {
 			nd6log(LOG_INFO, "bad DAD packet (wrong ip6 dst)\n");
 			goto bad;
+		}
 	} else {
 		struct sockaddr_in6 ssin6;
 		/*
 		 * Make sure the source address is from a neighbor's address.
 		 */
 		sockaddr_in6_init(&ssin6, &saddr6, 0, 0, 0);
 		if (nd6_is_addr_neighbor(&ssin6, ifp) == 0) {
 			nd6log(LOG_INFO,
 			    "NS packet from non-neighbor %s on %s\n",
 			    IN6_PRINT(ip6buf, &saddr6), if_name(ifp));
 			goto bad;
+		}
+	}
 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
 		nd6log(LOG_INFO, "bad NS target (multicast)\n");
 		goto bad;
+	}
 	icmp6len -= sizeof(*nd_ns);
 	nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
 	if (nd6_options(&ndopts) < 0) {
 		nd6log(LOG_INFO, "invalid ND option, ignored\n");
 		/* 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) {
 		nd6log(LOG_INFO,
 		    "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 multicast			MUST add
 	 * Otherwise					MAY be omitted
+	 *
 	 * In this implementation, we omit the target link-layer address
 	 * in the "MAY" case.
 	 */
 #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. */
 #if NCARP > 0
 	if (ifp->if_carp && ifp->if_type != IFT_CARP) {
 		int s = pserialize_read_enter();
 		ifa = carp_iamatch6(ifp->if_carp, &taddr6);
 		if (ifa != NULL)
 			ifa_acquire(ifa, &psref_ia);
 		pserialize_read_exit(s);
 	} else
 		ifa = NULL;
 	if (!ifa)
 		ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6,
 		    &psref_ia);
 #else
 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6,
 	    &psref_ia);
 #endif
 	/* (2) check. */
 	if (ifa == NULL) {
 		struct rtentry *rt;
 		struct sockaddr_in6 tsin6;
 		sockaddr_in6_init(&tsin6, &taddr6, 0, 0, 0);
 		rt = rtalloc1(sin6tosa(&tsin6), 0);
 		if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
 		    rt->rt_gateway->sa_family == AF_LINK) {
 			/*
 			 * proxy NDP for single entry
 			 */
 			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal_psref(ifp,
 				IN6_IFF_NOTREADY|IN6_IFF_ANYCAST, &psref_ia);
 			if (ifa) {
 				proxy = 1;
 				proxydl = satocsdl(rt->rt_gateway);
 				router = 0;	/* XXX */
+			}
+		}
 		if (rt)
 			rt_unref(rt);
+	}
 	if (ifa == NULL) {
 		/*
 		 * 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 = ((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)
 		goto freeit;
 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
 		nd6log(LOG_INFO, "lladdrlen mismatch for %s "
 		    "(if %d, NS packet %d)\n",
 		    IN6_PRINT(ip6buf, &taddr6),
 		    ifp->if_addrlen, lladdrlen - 2);
 		goto bad;
+	}
 	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
 		nd6log(LOG_INFO, "duplicate IP6 address %s\n",
 		    IN6_PRINT(ip6buf, &saddr6));
 		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
 		 * duplicate address detection.
+		 *
 		 * If not, the packet is for addess resolution;
 		 * silently ignore it.
 		 */
 		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
 			struct sockaddr_dl sdl, *sdlp;
 			if (lladdr != NULL)
 				sdlp = sockaddr_dl_init(&sdl, sizeof(sdl),
 				    ifp->if_index, ifp->if_type,
 				    NULL, 0, lladdr, lladdrlen);
 			else
 				sdlp = NULL;
 			nd6_dad_input(ifa, ndopts.nd_opts_nonce, sdlp);
+		}
 		goto freeit;
+	}
 	/*
 	 * It looks that sender is performing DAD.
 	 * Check that the nonce is not being used by the same address
 	 * on another interface.
 	 */
 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6) && ndopts.nd_opts_nonce != NULL) {
 		if (nd6_dad_ownnonce(ifa, ndopts.nd_opts_nonce))
 			goto freeit;
+	}
 	ifa_release(ifa, &psref_ia);
 	ifa = NULL;
 	/*
 	 * 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)) {
 		struct in6_addr in6_all;
 		in6_all = in6addr_linklocal_allnodes;
 		if (in6_setscope(&in6_all, ifp, NULL) != 0)
 			goto bad;
 		nd6_na_output(ifp, &in6_all, &taddr6,
 		    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
 		    (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
 		    tlladdr, (const struct sockaddr *)proxydl);
 		goto freeit;
+	}
 	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) |
 	    (router ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
 	    tlladdr, (const struct sockaddr *)proxydl);
  freeit:
 	ifa_release(ifa, &psref_ia);
 	m_put_rcvif_psref(ifp, &psref);
 	m_freem(m);
 	return;
  bad:
 	nd6log(LOG_ERR, "src=%s\n", IN6_PRINT(ip6buf, &saddr6));
 	nd6log(LOG_ERR, "dst=%s\n", IN6_PRINT(ip6buf, &daddr6));
 	nd6log(LOG_ERR, "tgt=%s\n", IN6_PRINT(ip6buf, &taddr6));
 	ICMP6_STATINC(ICMP6_STAT_BADNS);
 	ifa_release(ifa, &psref_ia);
 	m_put_rcvif_psref(ifp, &psref);
 	m_freem(m);
+}
 /*
  * Output a 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 (duplicate address detection)
  */
 void
 nd6_ns_output(struct ifnet *ifp, const struct in6_addr *daddr6,
     const struct in6_addr *taddr6,
     struct in6_addr *hsrc,
     uint8_t *nonce		/* duplicate address detection */)
+{
 	struct mbuf *m;
 	struct ip6_hdr *ip6;
 	struct nd_neighbor_solicit *nd_ns;
 	struct in6_addr *src, src_in;
 	struct ip6_moptions im6o;
 	int icmp6len;
 	int maxlen;
 	const void *mac;
 	struct route ro;
 	if (IN6_IS_ADDR_MULTICAST(taddr6))
 		return;
 	memset(&ro, 0, sizeof(ro));
 	/* estimate the size of message */
 	maxlen = sizeof(*ip6) + sizeof(*nd_ns);
 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
 	KASSERTMSG(max_linkhdr + maxlen <= MCLBYTES,
 	    "max_linkhdr + maxlen > MCLBYTES (%d + %d > %d)",
 	    max_linkhdr, maxlen, MCLBYTES);
 	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_reset_rcvif(m);
 	if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
 		m->m_flags |= M_MCAST;
 		im6o.im6o_multicast_if_index = if_get_index(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;
 	m->m_data += max_linkhdr;	/* or m_align() equivalent? */
 	/* 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;
 	if (daddr6)
 		ip6->ip6_dst = *daddr6;
 	else {
 		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
 		ip6->ip6_dst.s6_addr16[1] = 0;
 		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 (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
 			goto bad;
+	}
 	if (nonce == NULL) {
 		int s;
 		/*
 		 * 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
 		 * (hsrc), if:
 		 * - hsrc is given from the caller (by giving "ln"), and
 		 * - hsrc belongs to the outgoing interface.
 		 * Otherwise, we perform the source address selection as usual.
 		 */
 		s = pserialize_read_enter();
 		if (hsrc && in6ifa_ifpwithaddr(ifp, hsrc)) {
 			pserialize_read_exit(s);
 			src = hsrc;
 		} else {
 			int error;
 			struct sockaddr_in6 dst_sa;
 			pserialize_read_exit(s);
 			sockaddr_in6_init(&dst_sa, &ip6->ip6_dst, 0, 0, 0);
 			error = in6_selectsrc(&dst_sa, NULL,
 			    NULL, &ro, NULL, NULL, NULL, &src_in);
 			if (error != 0) {
 				char ip6buf[INET6_ADDRSTRLEN];
 				nd6log(LOG_DEBUG, "source can't be "
 				    "determined: dst=%s, error=%d\n",
 				    IN6_PRINT(ip6buf, &dst_sa.sin6_addr),
 				    error);
 				goto bad;
+			}
 			src = &src_in;
+		}
 	} 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.
 		 */
 		memset(&src_in, 0, sizeof(src_in));
 		src = &src_in;
+	}
 	ip6->ip6_src = *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;
 	in6_clearscope(&nd_ns->nd_ns_target); /* XXX */
 	/*
 	 * 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 (nonce == NULL && (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;
 		memset((void *)nd_opt, 0, optlen);
 		nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
 		nd_opt->nd_opt_len = optlen >> 3;
 		memcpy((void *)(nd_opt + 1), mac, ifp->if_addrlen);
+	}
 	/* Add a nonce option (RFC 3971) to detect looped back NS messages.
 	 * This behavior is documented in RFC 7527. */
 	if (nonce != NULL) {
 		int optlen = sizeof(struct nd_opt_hdr) + ND_OPT_NONCE_LEN;
 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
 		/* 8-byte alignment is required. */
 		optlen = (optlen + 7) & ~7;
 		m->m_pkthdr.len += optlen;
 		m->m_len += optlen;
 		icmp6len += optlen;
 		memset(nd_opt, 0, optlen);
 		nd_opt->nd_opt_type = ND_OPT_NONCE;
 		nd_opt->nd_opt_len = optlen >> 3;
 		memcpy(nd_opt + 1, nonce, ND_OPT_NONCE_LEN);
+	}
 	ip6->ip6_plen = htons((u_int16_t)icmp6len);
 	nd_ns->nd_ns_cksum = 0;
 	nd_ns->nd_ns_cksum =
 	    in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
 	ip6_output(m, NULL, &ro, nonce != NULL ? IPV6_UNSPECSRC : 0,
 	    &im6o, NULL, NULL);
 	icmp6_ifstat_inc(ifp, ifs6_out_msg);
 	icmp6_ifstat_inc(ifp, ifs6_out_neighborsolicit);
 	ICMP6_STATINC(ICMP6_STAT_OUTHIST + ND_NEIGHBOR_SOLICIT);
 	rtcache_free(&ro);
 	return;
   bad:
 	rtcache_free(&ro);
 	m_freem(m);
 	return;
+}
 /*
  * Neighbor advertisement input handling.
+ *
  * Based on RFC 2461
  * Based on RFC 2462 (duplicate 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 saddr6 = ip6->ip6_src;
 	struct in6_addr daddr6 = ip6->ip6_dst;
 	struct in6_addr taddr6;
 	int flags;
 	int is_router;
 	int is_solicited;
 	int is_override;
 	int rt_cmd;
 	char *lladdr = NULL;
 	int lladdrlen = 0;
 	struct ifaddr *ifa;
 	struct llentry *ln = NULL;
 	union nd_opts ndopts;
 	struct sockaddr_in6 ssin6;
 	bool checklink = false;
 	struct psref psref;
 	struct psref psref_ia;
 	char ip6buf[INET6_ADDRSTRLEN], ip6buf2[INET6_ADDRSTRLEN];
 	ifp = m_get_rcvif_psref(m, &psref);
 	if (ifp == NULL)
 		goto freeit;
 	if (ip6->ip6_hlim != 255) {
 		nd6log(LOG_ERR,
 		    "invalid hlim (%d) from %s to %s on %s\n",
 		    ip6->ip6_hlim, IN6_PRINT(ip6buf, &ip6->ip6_src),
 		    IN6_PRINT(ip6buf2, &ip6->ip6_dst), if_name(ifp));
 		goto bad;
+	}
 	IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
 	if (nd_na == NULL) {
 		m_put_rcvif_psref(ifp, &psref);
 		ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
 		return;
+	}
 	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);
 	taddr6 = nd_na->nd_na_target;
 	if (in6_setscope(&taddr6, ifp, NULL)) {
 		goto bad;
+	}
 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
 		nd6log(LOG_ERR, "invalid target address %s\n",
 		    IN6_PRINT(ip6buf, &taddr6));
 		goto bad;
+	}
 	if (is_solicited && IN6_IS_ADDR_MULTICAST(&daddr6)) {
 		nd6log(LOG_ERR, "a solicited adv is multicasted\n");
 		goto bad;
+	}
 	icmp6len -= sizeof(*nd_na);
 	nd6_option_init(nd_na + 1, icmp6len, &ndopts);
 	if (nd6_options(&ndopts) < 0) {
 		nd6log(LOG_INFO, "invalid ND option, ignored\n");
 		/* nd6_options have incremented stats */
 		goto freeit;
+	}
 	if (ndopts.nd_opts_tgt_lladdr != NULL) {
 		struct ifnet *ifp_ll;
 		struct psref psref_ll;
 		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
 		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
 		if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
 			nd6log(LOG_INFO, "lladdrlen mismatch for %s "
 			    "(if %d, NA packet %d)\n", IN6_PRINT(ip6buf, &taddr6),
 			    ifp->if_addrlen, lladdrlen - 2);
 			goto bad;
+		}
 		ifp_ll = if_get_bylla(lladdr, ifp->if_addrlen, &psref_ll);
 		if (ifp_ll != NULL) {
 			/* it's from me, ignore it. */
 			if_put(ifp_ll, &psref_ll);
 			goto freeit;
+		}
+	}
 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr_psref(ifp, &taddr6, &psref_ia);
 	/*
 	 * 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) {
 		if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE) {
 			struct sockaddr_dl sdl, *sdlp;
 			if (lladdr != NULL)
 				sdlp = sockaddr_dl_init(&sdl, sizeof(sdl),
 				    ifp->if_index, ifp->if_type,
 				    NULL, 0, lladdr, lladdrlen);
 			else
 				sdlp = NULL;
 			nd6_dad_input(ifa, NULL, sdlp);
 		} else
 			log(LOG_ERR,
 			    "nd6_na_input: duplicate IP6 address %s\n",
 			    IN6_PRINT(ip6buf, &taddr6));
 		ifa_release(ifa, &psref_ia);
 		ifa = NULL;
 		goto freeit;
+	}
 	/*
 	 * Make sure the source address is from a neighbor's address.
 	 */
 	sockaddr_in6_init(&ssin6, &saddr6, 0, 0, 0);
 	if (nd6_is_addr_neighbor(&ssin6, ifp) == 0) {
 		nd6log(LOG_INFO, "ND packet from non-neighbor %s on %s\n",
 		    IN6_PRINT(ip6buf, &saddr6), if_name(ifp));
 		goto bad;
+	}
 	/*
 	 * If no neighbor cache entry is found, NA SHOULD silently be
 	 * discarded.
 	 */
 	ln = nd6_lookup(&taddr6, ifp, true);
 	if (ln == NULL)
 		goto freeit;
 	rt_cmd = 0;
-	if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
+	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.
 		 */
 		memcpy(&ln->ll_addr, lladdr, ifp->if_addrlen);
 		ln->la_flags |= LLE_VALID;
 		rt_cmd = RTM_ADD;
 		if (is_solicited) {
 			ln->ln_state = ND6_LLINFO_REACHABLE;
 			ln->ln_byhint = 0;
 			if (!ND6_LLINFO_PERMANENT(ln)) {
 				nd6_llinfo_settimer(ln,
 				    ND_IFINFO(ln->lle_tbl->llt_ifp)->reachable * hz);
+			}
 		} else {
 			ln->ln_state = ND6_LLINFO_STALE;
 			nd6_llinfo_settimer(ln, nd6_gctimer * hz);
+		}
 		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..
 			 */
 			checklink = true;
+		}
 	} else {
 		bool llchange;
 		/*
 		 * Check if the link-layer address has changed or not.
 		 */
 		if (lladdr == NULL)
 			llchange = false;
 		else {
 			if (ln->la_flags & LLE_VALID) {
 				if (memcmp(lladdr, &ln->ll_addr, ifp->if_addrlen))
 					llchange = true;
 				else
 					llchange = false;
 			} else
 				llchange = true;
+		}
 		if (llchange)
 			rt_cmd = RTM_CHANGE;
 		/*
 		 * 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 != NULL && 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 * hz);
+			}
 			goto freeit;
 		} else if (is_override				   /* (2a) */
 		    || (!is_override && lladdr != NULL && !llchange) /* (2b) */
 		    || lladdr == NULL) {			   /* (2c) */
 			/*
 			 * Update link-local address, if any.
 			 */
 			if (lladdr != NULL) {
 				memcpy(&ln->ll_addr, lladdr, ifp->if_addrlen);
 				ln->la_flags |= LLE_VALID;
+			}
 			/*
 			 * 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;
 				ln->ln_byhint = 0;
 				if (!ND6_LLINFO_PERMANENT(ln)) {
 					nd6_llinfo_settimer(ln,
 					    ND_IFINFO(ifp)->reachable * hz);
+				}
 			} else {
 				if (lladdr && llchange) {
 					ln->ln_state = ND6_LLINFO_STALE;
 					nd6_llinfo_settimer(ln,
 					    nd6_gctimer * hz);
+				}
+			}
+		}
 		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.
 			 */
 			const struct in6_addr *in6 = &ln->r_l3addr.addr6;
 			struct nd_defrouter *dr;
 			ND6_WLOCK();
 			dr = nd6_defrouter_lookup(in6, ln->lle_tbl->llt_ifp);
 			if (dr)
 				nd6_defrtrlist_del(dr, NULL);
 			else if (!ip6_forwarding) {
 				/*
 				 * 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 nd6_rt_flush explicitly.
 				 */
 				nd6_rt_flush(&ip6->ip6_src, ln->lle_tbl->llt_ifp);
+			}
 			ND6_UNLOCK();
+		}
 		ln->ln_router = is_router;
+	}
         /*
 	 * XXX: does this matter?
 	 * rt->rt_flags &= ~RTF_REJECT;
 	 */
 	ln->ln_asked = 0;
 	nd6_llinfo_release_pkts(ln, ifp);
 	if (rt_cmd != 0) {
 		struct sockaddr_in6 sin6;
 		sockaddr_in6_init(&sin6, &ln->r_l3addr.addr6, 0, 0, 0);
 		rt_clonedmsg(rt_cmd, sin6tosa(&sin6),
 		    (char *)&ln->ll_addr, ln->lle_tbl->llt_ifp);
+	}
  freeit:
 	if (ln != NULL)
 		LLE_WUNLOCK(ln);
 	if (checklink) {
 		ND6_WLOCK();
 		nd6_pfxlist_onlink_check();
 		ND6_UNLOCK();
+	}
 	m_put_rcvif_psref(ifp, &psref);
 	m_freem(m);
 	return;
  bad:
 	if (ln != NULL)
 		LLE_WUNLOCK(ln);
 	ICMP6_STATINC(ICMP6_STAT_BADNA);
 	m_put_rcvif_psref(ifp, &psref);
 	m_freem(m);
+}
 /*
  * 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)
  */
 void
 nd6_na_output(
 	struct ifnet *ifp,
 	const struct in6_addr *daddr6_0,
 	const struct in6_addr *taddr6,
 	u_long flags,
 	int tlladdr,		/* 1 if include target link-layer address */
 	const struct sockaddr *sdl0)	/* sockaddr_dl (= proxy NA) or NULL */
+{
 	struct mbuf *m;
 	struct ip6_hdr *ip6;
 	struct nd_neighbor_advert *nd_na;
 	struct ip6_moptions im6o;
 	struct sockaddr *dst;
 	union {
 		struct sockaddr		dst;
 		struct sockaddr_in6	dst6;
 	} u;
 	struct in6_addr daddr6;
 	int icmp6len, maxlen, error;
 	const void *mac;
 	struct route ro;
 	mac = NULL;
 	memset(&ro, 0, sizeof(ro));
 	daddr6 = *daddr6_0;	/* make a local copy for modification */
 	/* estimate the size of message */
 	maxlen = sizeof(*ip6) + sizeof(*nd_na);
 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
 	KASSERTMSG(max_linkhdr + maxlen <= MCLBYTES,
 	    "max_linkhdr + maxlen > MCLBYTES (%d + %d > %d)",
 	    max_linkhdr, maxlen, MCLBYTES);
 	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_reset_rcvif(m);
 	if (IN6_IS_ADDR_MULTICAST(&daddr6)) {
 		m->m_flags |= M_MCAST;
 		im6o.im6o_multicast_if_index = if_get_index(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;
 	m->m_data += max_linkhdr;	/* or m_align() equivalent? */
 	/* 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;
 	if (IN6_IS_ADDR_UNSPECIFIED(&daddr6)) {
 		/* reply to DAD */
 		daddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
 		daddr6.s6_addr16[1] = 0;
 		daddr6.s6_addr32[1] = 0;
 		daddr6.s6_addr32[2] = 0;
 		daddr6.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
 		if (in6_setscope(&daddr6, ifp, NULL))
 			goto bad;
 		flags &= ~ND_NA_FLAG_SOLICITED;
+	}
 	ip6->ip6_dst = daddr6;
 	sockaddr_in6_init(&u.dst6, &daddr6, 0, 0, 0);
 	dst = &u.dst;
 	if (rtcache_setdst(&ro, dst) != 0)
 		goto bad;
 	/*
 	 * Select a source whose scope is the same as that of the dest.
 	 */
 	error = in6_selectsrc(satosin6(dst), NULL, NULL, &ro, NULL, NULL, NULL,
 	    &ip6->ip6_src);
 	if (error != 0) {
 		char ip6buf[INET6_ADDRSTRLEN];
 		nd6log(LOG_DEBUG, "source can't be "
 		    "determined: dst=%s, error=%d\n",
 		    IN6_PRINT(ip6buf, &satocsin6(dst)->sin6_addr), error);
 		goto bad;
+	}
 	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;
 	in6_clearscope(&nd_na->nd_na_target); /* XXX */
 	/*
 	 * "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) {
 			const struct sockaddr_dl *sdl;
 			sdl = satocsdl(sdl0);
 			if (sdl->sdl_alen == ifp->if_addrlen)
 				mac = CLLADDR(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;
 		memset((void *)nd_opt, 0, optlen);
 		nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
 		nd_opt->nd_opt_len = optlen >> 3;
 		memcpy((void *)(nd_opt + 1), mac, ifp->if_addrlen);
 	} else
 		flags &= ~ND_NA_FLAG_OVERRIDE;
 	ip6->ip6_plen = htons((u_int16_t)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);
 	ip6_output(m, NULL, NULL, 0, &im6o, NULL, NULL);
 	icmp6_ifstat_inc(ifp, ifs6_out_msg);
 	icmp6_ifstat_inc(ifp, ifs6_out_neighboradvert);
 	ICMP6_STATINC(ICMP6_STAT_OUTHIST + ND_NEIGHBOR_ADVERT);
 	rtcache_free(&ro);
 	return;
   bad:
 	rtcache_free(&ro);
 	m_freem(m);
 	return;
+}
 const void *
 nd6_ifptomac(const struct ifnet *ifp)
+{
 	switch (ifp->if_type) {
 	case IFT_ARCNET:
 	case IFT_ETHER:
 	case IFT_FDDI:
 	case IFT_IEEE1394:
 	case IFT_PROPVIRTUAL:
 	case IFT_CARP:
 	case IFT_L2VLAN:
 	case IFT_IEEE80211:
 		return CLLADDR(ifp->if_sadl);
 	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_lcount;		/* looped back NS */
 	struct callout dad_timer_ch;
 #define	ND_OPT_NONCE_STORE	3	/* dad_count should not exceed this */
 	/*
 	 * The default ip6_dad_count is 1 as specified by RFC 4862 and
 	 * practically must users won't exceed this.
 	 * A storage of 3 is defaulted to here, in-case the administrator wants
 	 * to match the equivalent behaviour in our ARP implementation.
 	 * This constraint could be removed by sending the on wire nonce as
 	 * hmac(key, dad_ns_ocount), but that would increase the nonce size
 	 * sent on the wire.
 	 */
 	uint8_t dad_nonce[ND_OPT_NONCE_STORE][ND_OPT_NONCE_LEN];
 };
 static struct dadq_head dadq;
 static kmutex_t nd6_dad_lock;
 void
 nd6_nbr_init(void)
+{
 	TAILQ_INIT(&dadq);
 	mutex_init(&nd6_dad_lock, MUTEX_DEFAULT, IPL_NONE);
+}
 static struct dadq *
 nd6_dad_find(struct ifaddr *ifa, struct nd_opt_nonce *nonce, bool *found_nonce)
+{
 	struct in6_addr *myaddr6, *dadaddr6;
 	bool match_ifa;
 	struct dadq *dp;
 	int i, nonce_max;
 	KASSERT(mutex_owned(&nd6_dad_lock));
 	KASSERT(ifa != NULL);
 	myaddr6 = IFA_IN6(ifa);
 	if (nonce != NULL &&
 	    nonce->nd_opt_nonce_len != (ND_OPT_NONCE_LEN + 2) / 8)
 		nonce = NULL;
 	match_ifa = nonce == NULL || found_nonce == NULL || *found_nonce == false;
 	if (found_nonce != NULL)
 		*found_nonce = false;
 	TAILQ_FOREACH(dp, &dadq, dad_list) {
 		if (match_ifa) {
 			if (dp->dad_ifa != ifa)
 				continue;
 		} else {
 			dadaddr6 = IFA_IN6(dp->dad_ifa);
 			if (!IN6_ARE_ADDR_EQUAL(myaddr6, dadaddr6))
 				continue;
+		}
 		if (nonce == NULL)
 			break;
 		nonce_max = MIN(dp->dad_ns_ocount, ND_OPT_NONCE_STORE);
 		for (i = 0; i < nonce_max; i++) {
 			if (memcmp(nonce->nd_opt_nonce,
 			    dp->dad_nonce[i],
 			    ND_OPT_NONCE_LEN) == 0)
 				break;
+		}
 		if (i < nonce_max) {
 			char ip6buf[INET6_ADDRSTRLEN];
 			*found_nonce = true;
 			log(LOG_DEBUG,
 			    "%s: detected a looped back NS message for %s\n",
 			    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???",
 			    IN6_PRINT(ip6buf, myaddr6));
 			dp->dad_ns_lcount++;
 			continue;
+		}
 		break;
+	}
 	return dp;
+}
 static bool
 nd6_dad_ownnonce(struct ifaddr *ifa, struct nd_opt_nonce *nonce)
+{
 	bool found_nonce = true;
 	mutex_enter(&nd6_dad_lock);
 	nd6_dad_find(ifa, nonce, &found_nonce);
 	mutex_exit(&nd6_dad_lock);
 	return found_nonce;
+}
 static void
 nd6_dad_starttimer(struct dadq *dp, int ticks)
+{
 	callout_reset(&dp->dad_timer_ch, ticks,
 	    (void (*)(void *))nd6_dad_timer, dp);
+}
 static void
 nd6_dad_stoptimer(struct dadq *dp)
+{
 	KASSERT(mutex_owned(&nd6_dad_lock));
 	TAILQ_REMOVE(&dadq, dp, dad_list);
 	/* Tell the timer that dp is being destroyed. */
 	dp->dad_ifa = NULL;
 	callout_halt(&dp->dad_timer_ch, &nd6_dad_lock);
+}
 static void
 nd6_dad_destroytimer(struct dadq *dp)
+{
 	KASSERT(dp->dad_ifa == NULL);
 	callout_destroy(&dp->dad_timer_ch);
 	kmem_intr_free(dp, sizeof(*dp));
+}
 /*
  * Start Duplicate Address Detection (DAD) for specified interface address.
+ *
  * Note that callout is used when xtick > 0 and not when xtick == 0.
+ *
  * xtick: minimum delay ticks for IFF_UP event
  */
 void
 nd6_dad_start(struct ifaddr *ifa, int xtick)
+{
 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 	struct dadq *dp;
 	char ip6buf[INET6_ADDRSTRLEN];
 	/*
 	 * If we don't need DAD, don't do it.
 	 * There are several cases:
 	 * - DAD is disabled
 	 * - the interface address is anycast
 	 */
 	if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
 		log(LOG_DEBUG,
 			"nd6_dad_start: called with non-tentative address "
 			"%s(%s)\n",
 			IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr),
 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 		return;
+	}
 	if (ia->ia6_flags & IN6_IFF_ANYCAST || !ip6_dad_enabled()) {
 		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 		rt_addrmsg(RTM_NEWADDR, ifa);
 		return;
+	}
 	KASSERT(ifa->ifa_ifp != NULL);
 	if (!(ifa->ifa_ifp->if_flags & IFF_UP))
 		return;
 	dp = kmem_intr_alloc(sizeof(*dp), KM_NOSLEEP);
 	mutex_enter(&nd6_dad_lock);
 	if (nd6_dad_find(ifa, NULL, NULL) != NULL) {
 		mutex_exit(&nd6_dad_lock);
 		/* DAD already in progress */
 		if (dp != NULL)
 			kmem_intr_free(dp, sizeof(*dp));
 		return;
+	}
 	if (dp == NULL) {
 		mutex_exit(&nd6_dad_lock);
 		log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
 			"%s(%s)\n",
 			IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr),
 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 		return;
+	}
 	/*
 	 * 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.
 	 */
 	callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE);
 	dp->dad_ifa = ifa;
 	ifaref(ifa);	/* just for safety */
 	dp->dad_count = ip6_dad_count;
 	dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
 	dp->dad_ns_lcount = 0;
 	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
 	nd6log(LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
 	    IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr));
 	if (xtick == 0) {
 		nd6_dad_ns_output(dp, ifa);
 		nd6_dad_starttimer(dp,
 		    (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
 	} else
 		nd6_dad_starttimer(dp, xtick);
 	mutex_exit(&nd6_dad_lock);
+}
 /*
  * terminate DAD unconditionally.  used for address removals.
  */
 void
 nd6_dad_stop(struct ifaddr *ifa)
+{
 	struct dadq *dp;
 	mutex_enter(&nd6_dad_lock);
 	dp = nd6_dad_find(ifa, NULL, NULL);
 	if (dp == NULL) {
 		mutex_exit(&nd6_dad_lock);
 		/* DAD wasn't started yet */
 		return;
+	}
 	/* Prevent the timer from running anymore. */
 	nd6_dad_stoptimer(dp);
 	mutex_exit(&nd6_dad_lock);
 	nd6_dad_destroytimer(dp);
 	ifafree(ifa);
+}
 static void
 nd6_dad_timer(struct dadq *dp)
+{
 	struct ifaddr *ifa;
 	struct in6_ifaddr *ia;
 	char ip6buf[INET6_ADDRSTRLEN];
 	bool need_free = false;
 	KERNEL_LOCK_UNLESS_NET_MPSAFE();
 	mutex_enter(&nd6_dad_lock);
 	ifa = dp->dad_ifa;
 	if (ifa == NULL) {
 		/* dp is being destroyed by someone.  Do nothing. */
 		goto done;
+	}
 	ia = (struct in6_ifaddr *)ifa;
 	if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
 		log(LOG_ERR, "nd6_dad_timer: called with duplicate address "
 			"%s(%s)\n",
 			IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr),
 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
 		goto done;
+	}
 	if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
 		log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
 			"%s(%s)\n",
 			IN6_PRINT(ip6buf, &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) {
 		nd6log(LOG_INFO, "%s: could not run DAD, driver problem?\n",
 			if_name(ifa->ifa_ifp));
 		nd6_dad_stoptimer(dp);
 		need_free = true;
 		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,
 		    (long)ND_IFINFO(ifa->ifa_ifp)->retrans * hz / 1000);
 	} else {
 		/*
 		 * We are done with DAD.  No NA came, no NS came.
 		 * No duplicate address found.
 		 */
 		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 		rt_addrmsg(RTM_NEWADDR, ifa);
 		nd6log(LOG_DEBUG,
 		    "%s: DAD complete for %s - no duplicates found\n",
 		    if_name(ifa->ifa_ifp),
 		    IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr));
 		nd6_dad_stoptimer(dp);
 		need_free = true;
+	}
 done:
 	mutex_exit(&nd6_dad_lock);
 	if (need_free) {
 		nd6_dad_destroytimer(dp);
 		KASSERT(ifa != NULL);
 		ifafree(ifa);
+	}
 	KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
+}
 static void
 nd6_dad_duplicated(struct ifaddr *ifa, struct dadq *dp,
     const struct sockaddr_dl *from)
+{
 	struct in6_ifaddr *ia;
 	struct ifnet *ifp;
 	char ip6buf[INET6_ADDRSTRLEN], llabuf[LLA_ADDRSTRLEN], *llastr;
 	KASSERT(mutex_owned(&nd6_dad_lock));
 	KASSERT(ifa != NULL);
 	ifp = ifa->ifa_ifp;
 	ia = (struct in6_ifaddr *)ifa;
 	ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 	ia->ia6_flags |= IN6_IFF_DUPLICATED;
 	if (__predict_false(from == NULL))
 		llastr = NULL;
 	else
 		llastr = lla_snprintf(llabuf, sizeof(llabuf),
 		    CLLADDR(from), from->sdl_alen);
 	log(LOG_ERR, "%s: DAD duplicate address %s from %s\n",
 	    if_name(ifp), IN6_PRINT(ip6buf, &ia->ia_addr.sin6_addr), llastr);
 	/* Inform the routing socket that DAD has completed */
 	rt_addrmsg_src(RTM_NEWADDR, ifa, (const struct sockaddr *)from);
 	/*
 	 * If the address is a link-local address formed from an interface
 	 * identifier based on the hardware address which is supposed to be
 	 * uniquely assigned (e.g., EUI-64 for an Ethernet interface), IP
 	 * operation on the interface SHOULD be disabled.
 	 * [rfc2462bis-03 Section 5.4.5]
 	 */
 	if (IN6_IS_ADDR_LINKLOCAL(&ia->ia_addr.sin6_addr)) {
 		struct in6_addr in6;
 		/*
 		 * To avoid over-reaction, we only apply this logic when we are
 		 * very sure that hardware addresses are supposed to be unique.
 		 */
 		switch (ifp->if_type) {
 		case IFT_ETHER:
 		case IFT_FDDI:
 		case IFT_ATM:
 		case IFT_IEEE1394:
 		case IFT_IEEE80211:
 			in6 = ia->ia_addr.sin6_addr;
 			if (in6_get_hw_ifid(ifp, &in6) == 0 &&
 			    IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, &in6)) {
 				ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED;
 				log(LOG_ERR, "%s: possible hardware address "
 				    "duplication detected, disable IPv6\n",
 				    if_name(ifp));
+			}
 			break;
+		}
+	}
+}
 static void
 nd6_dad_ns_output(struct dadq *dp, struct ifaddr *ifa)
+{
 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
 	struct ifnet *ifp = ifa->ifa_ifp;
 	uint8_t *nonce;
 	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_tcount = 0;
 	nonce = dp->dad_nonce[dp->dad_ns_ocount % ND_OPT_NONCE_STORE];
 	cprng_fast(nonce, ND_OPT_NONCE_LEN);
 	dp->dad_ns_ocount++;
 	nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, nonce);
+}
 static void
 nd6_dad_input(struct ifaddr *ifa, struct nd_opt_nonce *nonce,
     const struct sockaddr_dl *from)
+{
 	struct dadq *dp;
 	bool found_nonce = false;
 	KASSERT(ifa != NULL);
 	mutex_enter(&nd6_dad_lock);
 	dp = nd6_dad_find(ifa, nonce, &found_nonce);
 	if (!found_nonce) {
 		nd6_dad_duplicated(ifa, dp, from);
 		if (dp != NULL)
 			nd6_dad_stoptimer(dp);
+	}
 	mutex_exit(&nd6_dad_lock);
 	if (dp != NULL) {
 		nd6_dad_destroytimer(dp);
 		ifafree(ifa);
+	}
+}