revisit in6_ifattach(). (1) make it more persistent about initializaing an

interface (2) cleanup interface id selection.
run NUD on p2p interface (required by spec for bidir p2p interface).
add "ndp -i interface" (can tweak per-interface ND flag).
(sync with more recent kame)

9 files changed, 747 insertions, 555 deletions

diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index 5e1930cb4e9..44dffbf33cf 100644
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -1,5 +1,4 @@
-/*	$OpenBSD: in6.c,v 1.17 2000/03/22 03:48:30 itojun Exp $	*/
-/*	$KAME: in6.c,v 1.63 2000/03/21 05:18:38 itojun Exp $	*/
+/*	$KAME: in6.c,v 1.75 2000/04/12 03:51:29 itojun Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -82,11 +81,9 @@
 #include <net/if_types.h>
 #include <net/route.h>
 #include "gif.h"
-
 #if NGIF > 0
 #include <net/if_gif.h>
 #endif
-
 #include <net/if_dl.h>
 
 #include <netinet/in.h>
@@ -309,7 +306,7 @@ in6_control(so, cmd, data, ifp, p)
 	struct	in6_aliasreq *ifra = (struct in6_aliasreq *)data;
 	struct	sockaddr_in6 oldaddr;
 #ifdef COMPAT_IN6IFIOCTL
-	struct sockaddr_in6 net;
+	struct	sockaddr_in6 net;
 #endif
 	int error = 0, hostIsNew, prefixIsNew;
 	int newifaddr;
@@ -350,6 +347,7 @@ in6_control(so, cmd, data, ifp, p)
 	case SIOCSPFXFLUSH_IN6:
 	case SIOCSRTRFLUSH_IN6:
 	case SIOCSDEFIFACE_IN6:
+	case SIOCSIFINFO_FLAGS:
 		if (!privileged)
 			return(EPERM);
 		/*fall through*/
@@ -396,8 +394,7 @@ in6_control(so, cmd, data, ifp, p)
 				/* interface ID is not embedded by the user */
 				sa6->sin6_addr.s6_addr16[1] =
 					htons(ifp->if_index);
-			}
-			else if (sa6->sin6_addr.s6_addr16[1] !=
+			} else if (sa6->sin6_addr.s6_addr16[1] !=
 				    htons(ifp->if_index)) {
 				return(EINVAL);	/* ifid is contradict */
 			}
@@ -434,7 +431,7 @@ in6_control(so, cmd, data, ifp, p)
 		 * on a single interface, SIOCSIFxxx ioctls are not suitable
 		 * and should be unused.
 		 */
-#endif 
+#endif
 		if (ifra->ifra_addr.sin6_family != AF_INET6)
 			return(EAFNOSUPPORT);
 		if (!privileged)
@@ -584,8 +581,7 @@ in6_control(so, cmd, data, ifp, p)
 				/* interface ID is not embedded by the user */
 				ia->ia_dstaddr.sin6_addr.s6_addr16[1]
 					= htons(ifp->if_index);
-			}
-			else if (ia->ia_dstaddr.sin6_addr.s6_addr16[1] !=
+			} else if (ia->ia_dstaddr.sin6_addr.s6_addr16[1] !=
 				    htons(ifp->if_index)) {
 				ia->ia_dstaddr = oldaddr;
 				return(EINVAL);	/* ifid is contradict */
@@ -606,7 +602,7 @@ in6_control(so, cmd, data, ifp, p)
 		}
 		break;
 
-#endif 
+#endif
 	case SIOCGIFALIFETIME_IN6:
 		ifr->ifr_ifru.ifru_lifetime = ia->ia6_lifetime;
 		break;
@@ -681,7 +677,7 @@ in6_control(so, cmd, data, ifp, p)
 				ia->ia_prefixmask.sin6_addr.s6_addr32[3];
 		ia->ia_net = net;
 		break;
-#endif 
+#endif
 
 	case SIOCAIFADDR_IN6:
 		prefixIsNew = 0;
@@ -1267,8 +1263,7 @@ in6_savemkludge(oia)
 
 		if (mk->mk_head.lh_first != NULL) {
 			LIST_INSERT_HEAD(&in6_mk, mk, mk_entry);
-		}
-		else {
+		} else {
 			FREE(mk, M_IPMADDR);
 		}
 	}
@@ -1734,7 +1729,7 @@ in6_ifawithscope(oifp, dst)
 	register struct ifnet *oifp;
 	register struct in6_addr *dst;
 {
-	int dst_scope =	in6_addrscope(dst), src_scope, best_scope;
+	int dst_scope =	in6_addrscope(dst), src_scope, best_scope = 0;
 	int blen = -1;
 	struct ifaddr *ifa;
 	struct ifnet *ifp;
@@ -2074,64 +2069,13 @@ in6_if_up(ifp)
 {
 	struct ifaddr *ifa;
 	struct in6_ifaddr *ia;
-	struct sockaddr_dl *sdl;
-	int type;
-	struct ether_addr ea;
-	int off;
 	int dad_delay;		/* delay ticks before DAD output */
 
-	bzero(&ea, sizeof(ea));
-	sdl = NULL;
-
-	for (ifa = ifp->if_addrlist.tqh_first;
-	     ifa;
-	     ifa = ifa->ifa_list.tqe_next)
-	{
-		if (ifa->ifa_addr->sa_family == AF_INET6
-		 && IN6_IS_ADDR_LINKLOCAL(&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr)) {
-			goto dad;
-		}
-		if (ifa->ifa_addr->sa_family != AF_LINK)
-			continue;
-		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
-		break;
-	}
-
-	switch (ifp->if_type) {
-	case IFT_LOOP:
-		in6_ifattach(ifp, IN6_IFT_LOOP, NULL, 1);
-		break;
-	case IFT_SLIP:
-	case IFT_PPP:
-	case IFT_DUMMY:
-	case IFT_GIF:
-	case IFT_FAITH:
-		type = IN6_IFT_P2P;
-		in6_ifattach(ifp, type, 0, 1);
-		break;
-	case IFT_ETHER:
-	case IFT_FDDI:
-	case IFT_ATM:
-		type = IN6_IFT_802;
-		if (sdl == NULL)
-			break;
-		off = sdl->sdl_nlen;
-		if (bcmp(&sdl->sdl_data[off], &ea, sizeof(ea)) != 0)
-			in6_ifattach(ifp, type, LLADDR(sdl), 0);
-		break;
-	case IFT_ARCNET:
-		type = IN6_IFT_ARCNET;
-		if (sdl == NULL)
-			break;
-		off = sdl->sdl_nlen;
-		if (sdl->sdl_data[off] != 0)	/* XXX ?: */
-			in6_ifattach(ifp, type, LLADDR(sdl), 0);
-		break;
-	default:
-		break;
-	}
+	/*
+	 * special cases, like 6to4, are handled in in6_ifattach
+	 */
+	in6_ifattach(ifp, NULL);
 
-dad:
 	dad_delay = 0;
 	for (ifa = ifp->if_addrlist.tqh_first;
 	     ifa;
diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c
index 8a981dd412c..e2d7111ffe7 100644
--- a/sys/netinet6/in6_ifattach.c
+++ b/sys/netinet6/in6_ifattach.c
@@ -1,10 +1,10 @@
-/*	$OpenBSD: in6_ifattach.c,v 1.7 2000/03/02 09:44:28 itojun Exp $	*/
-/*	$KAME: in6_ifattach.c,v 1.39 2000/03/02 09:24:45 itojun Exp $	*/
+/*	$OpenBSD: in6_ifattach.c,v 1.8 2000/04/17 04:44:50 itojun Exp $	*/
+/*	$KAME: in6_ifattach.c,v 1.53 2000/04/16 14:01:42 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:
@@ -16,7 +16,7 @@
  * 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
@@ -55,225 +55,536 @@
 
 #include <net/net_osdep.h>
 
-static	struct in6_addr llsol;
-
 struct in6_ifstat **in6_ifstat = NULL;
 struct icmp6_ifstat **icmp6_ifstat = NULL;
 size_t in6_ifstatmax = 0;
 size_t icmp6_ifstatmax = 0;
 unsigned long in6_maxmtu = 0;
 
-int found_first_ifid = 0;
-#define IFID_LEN 8
-static u_int8_t first_ifid[IFID_LEN];
+static int get_rand_ifid __P((struct ifnet *, struct in6_addr *));
+static int get_hw_ifid __P((struct ifnet *, struct in6_addr *));
+static int get_ifid __P((struct ifnet *, struct ifnet *, struct in6_addr *));
+static int in6_ifattach_addaddr __P((struct ifnet *, struct in6_ifaddr *));
+static int in6_ifattach_linklocal __P((struct ifnet *, struct ifnet *));
+static int in6_ifattach_loopback __P((struct ifnet *));
 
-static int laddr_to_eui64 __P((u_int8_t *, u_int8_t *, size_t));
-static int gen_rand_eui64 __P((u_int8_t *));
+#define EUI64_GBIT	0x01
+#define EUI64_UBIT	0x02
+#define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
+#define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
+#define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
+#define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
+#define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))
 
-static int
-laddr_to_eui64(dst, src, len)
-	u_int8_t *dst;
-	u_int8_t *src;
-	size_t len;
-{
-	static u_int8_t zero[8];
-
-	bzero(zero, sizeof(zero));
-
-	switch (len) {
-	case 6:
-		if (bcmp(zero, src, 6) == 0)
-			return EINVAL;
-		dst[0] = src[0];
-		dst[1] = src[1];
-		dst[2] = src[2];
-		dst[3] = 0xff;
-		dst[4] = 0xfe;
-		dst[5] = src[3];
-		dst[6] = src[4];
-		dst[7] = src[5];
-		break;
-	case 8:
-		if (bcmp(zero, src, 8) == 0)
-			return EINVAL;
-		bcopy(src, dst, len);
-		break;
-	default:
-		return EINVAL;
-	}
-
-	return 0;
-}
+#define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
+#define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
 
 /*
  * Generate a last-resort interface identifier, when the machine has no
  * IEEE802/EUI64 address sources.
- * The address should be random, and should not change across reboot.
+ * The goal here is to get an interface identifier that is
+ * (1) random enough and (2) does not change across reboot.
+ * We currently use MD5(hostname) for it.
  */
 static int
-gen_rand_eui64(dst)
-	u_int8_t *dst;
+get_rand_ifid(ifp, in6)
+	struct ifnet *ifp;
+	struct in6_addr *in6;	/*upper 64bits are preserved */
 {
 	MD5_CTX ctxt;
 	u_int8_t digest[16];
 
-	/* generate 8bytes of pseudo-random value. */
+#if 0
+	/* we need at least several letters as seed for ifid */
+	if (hostnamelen < 3)
+		return -1;
+#endif
+
+	/* generate 8 bytes of pseudo-random value. */
 	bzero(&ctxt, sizeof(ctxt));
 	MD5Init(&ctxt);
 	MD5Update(&ctxt, hostname, hostnamelen);
 	MD5Final(digest, &ctxt);
 
-	/* assumes sizeof(digest) > sizeof(first_ifid) */
-	bcopy(digest, dst, 8);
+	/* assumes sizeof(digest) > sizeof(ifid) */
+	bcopy(digest, &in6->s6_addr[8], 8);
 
 	/* make sure to set "u" bit to local, and "g" bit to individual. */
-	dst[0] &= 0xfe;
-	dst[0] |= 0x02;		/* EUI64 "local" */
+	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
+	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
+
+	/* convert EUI64 into IPv6 interface identifier */
+	EUI64_TO_IFID(in6);
 
 	return 0;
 }
 
 /*
- * Find first ifid on list of interfaces.
- * This is assumed that ifp0's interface token (for example, IEEE802 MAC)
- * is globally unique.  We may need to have a flag parameter in the future.
+ * Get interface identifier for the specified interface.
+ * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
  */
-int
-in6_ifattach_getifid(ifp0)
-	struct ifnet *ifp0;
-{
+static int
+get_hw_ifid(ifp, in6)
 	struct ifnet *ifp;
+	struct in6_addr *in6;	/*upper 64bits are preserved */
+{
 	struct ifaddr *ifa;
-	u_int8_t *addr = NULL;
-	int addrlen = 0;
 	struct sockaddr_dl *sdl;
+	u_int8_t *addr;
+	size_t addrlen;
+	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+	static u_int8_t allone[8] =
+		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+
+	for (ifa = ifp->if_addrlist.tqh_first;
+	     ifa;
+	     ifa = ifa->ifa_list.tqe_next)
+	{
+		if (ifa->ifa_addr->sa_family != AF_LINK)
+			continue;
+		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
+		if (sdl == NULL)
+			continue;
+		if (sdl->sdl_alen == 0)
+			continue;
+
+		goto found;
+	}
+
+	return -1;
+
+found:
+	addr = LLADDR(sdl);
+	addrlen = sdl->sdl_alen;
+
+	/* get EUI64 */
+	switch (ifp->if_type) {
+	case IFT_ETHER:
+	case IFT_FDDI:
+	case IFT_ATM:
+		/* IEEE802/EUI64 cases - what others? */
+
+		/* look at IEEE802/EUI64 only */
+		if (addrlen != 8 && addrlen != 6)
+			return -1;
+
+		/*
+		 * check for invalid MAC address - on bsdi, we see it a lot
+		 * since wildboar configures all-zero MAC on pccard before
+		 * card insertion.
+		 */
+		if (bcmp(addr, allzero, addrlen) == 0)
+			return -1;
+		if (bcmp(addr, allone, addrlen) == 0)
+			return -1;
+
+		/* make EUI64 address */
+		if (addrlen == 8)
+			bcopy(addr, &in6->s6_addr[8], 8);
+		else if (addrlen == 6) {
+			in6->s6_addr[8] = addr[0];
+			in6->s6_addr[9] = addr[1];
+			in6->s6_addr[10] = addr[2];
+			in6->s6_addr[11] = 0xff;
+			in6->s6_addr[12] = 0xfe;
+			in6->s6_addr[13] = addr[3];
+			in6->s6_addr[14] = addr[4];
+			in6->s6_addr[15] = addr[5];
+		}
+		break;
+
+	case IFT_ARCNET:
+		if (addrlen != 1)
+			return -1;
+		if (!addr[0])
+			return -1;
+
+		bzero(&in6->s6_addr[8], 8);
+		in6->s6_addr[15] = addr[0];
+
+		/*
+		 * due to insufficient bitwidth, we mark it local.
+		 */
+		in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
+		in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
+		break;
+
+	case IFT_GIF:
+#ifdef IFT_STF
+	case IFT_STF:
+#endif
+		/*
+		 * mech-06 says: "SHOULD use IPv4 address as ifid source".
+		 * however, IPv4 address is not very suitable as unique
+		 * identifier source (can be renumbered).
+		 * we don't do this.
+		 */
+		return -1;
+
+	default:
+		return -1;
+	}
+
+	/* sanity check: g bit must not indicate "group" */
+	if (EUI64_GROUP(in6))
+		return -1;
+
+	/* convert EUI64 into IPv6 interface identifier */
+	EUI64_TO_IFID(in6);
+
+	/*
+	 * sanity check: ifid must not be all zero, avoid conflict with
+	 * subnet router anycast
+	 */
+	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
+	    bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Get interface identifier for the specified interface.  If it is not
+ * available on ifp0, borrow interface identifier from other information
+ * sources.
+ */
+static int
+get_ifid(ifp0, altifp, in6)
+	struct ifnet *ifp0;
+	struct ifnet *altifp;	/*secondary EUI64 source*/
+	struct in6_addr *in6;
+{
+	struct ifnet *ifp;
 
-	if (found_first_ifid)
-		return 0;
+	/* first, try to get it from the interface itself */
+	if (get_hw_ifid(ifp0, in6) == 0) {
+#ifdef ND6_DEBUG
+		printf("%s: got interface identifier from itself\n",
+		    if_name(ifp0));
+#endif
+		goto success;
+	}
 
+	/* try secondary EUI64 source. this basically is for ATM PVC */
+	if (altifp && get_hw_ifid(altifp, in6) == 0) {
+#ifdef ND6_DEBUG
+		printf("%s: got interface identifier from %s\n",
+		    if_name(ifp0), ifname(altifp));
+#endif
+		goto success;
+	}
+
+	/* next, try to get it from some other hardware interface */
 	for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_list.tqe_next)
 	{
-		if (ifp0 != NULL && ifp0 != ifp)
+		if (ifp == ifp0)
 			continue;
-		for (ifa = ifp->if_addrlist.tqh_first;
-		     ifa;
-		     ifa = ifa->ifa_list.tqe_next)
-		{
-			if (ifa->ifa_addr->sa_family != AF_LINK)
-				continue;
-			sdl = (struct sockaddr_dl *)ifa->ifa_addr;
-			if (sdl == NULL)
-				continue;
-			if (sdl->sdl_alen == 0)
-				continue;
-			switch (ifp->if_type) {
-			case IFT_ETHER:
-			case IFT_FDDI:
-			case IFT_ATM:
-				/* IEEE802/EUI64 cases - what others? */
-				addr = LLADDR(sdl);
-				addrlen = sdl->sdl_alen;
-				/*
-				 * to copy ifid from IEEE802/EUI64 interface,
-				 * u bit of the source needs to be 0.
-				 */
-				if ((addr[0] & 0x02) != 0)
-					break;
-				goto found;
-			case IFT_ARCNET:
-				/*
-				 * ARCnet interface token cannot be used as
-				 * globally unique identifier due to its 
-				 * small bitwidth.
-				 */
-				break;
-			default:
-				break;
-			}
+		if (get_hw_ifid(ifp, in6) != 0)
+			continue;
+
+		/*
+		 * to borrow ifid from other interface, ifid needs to be
+		 * globally unique
+		 */
+		if (IFID_UNIVERSAL(in6)) {
+
+#ifdef ND6_DEBUG
+			printf("%s: borrow interface identifier from %s\n",
+			    if_name(ifp0), if_name(ifp));
+#endif
+			goto success;
 		}
 	}
-#ifdef DEBUG
-	printf("in6_ifattach_getifid: failed to get EUI64");
+
+	/* last resort: get from random number source */
+	if (get_rand_ifid(ifp, in6) == 0) {
+#ifdef ND6_DEBUG
+		printf("%s: interface identifier generated by random number\n",
+		    if_name(ifp0));
 #endif
-	return EADDRNOTAVAIL;
+		goto success;
+	}
 
-found:
-	if (laddr_to_eui64(first_ifid, addr, addrlen) == 0)
-		found_first_ifid = 1;
-
-	if (found_first_ifid) {
-		printf("%s: supplying EUI64: "
-			"%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
-			if_name(ifp),
-			first_ifid[0], first_ifid[1],
-			first_ifid[2], first_ifid[3],
-			first_ifid[4], first_ifid[5],
-			first_ifid[6], first_ifid[7]);
-
-		/* invert u bit to convert EUI64 to RFC2373 interface ID. */
-		first_ifid[0] ^= 0x02;
-
-		return 0;
+	printf("%s: failed to get interface identifier", if_name(ifp0));
+	return -1;
+
+success:
+#ifdef ND6_DEBUG
+	printf("%s: ifid: "
+		"%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
+		if_name(ifp0),
+		in6->s6_addr[8], in6->s6_addr[9],
+		in6->s6_addr[10], in6->s6_addr[11],
+		in6->s6_addr[12], in6->s6_addr[13],
+		in6->s6_addr[14], in6->s6_addr[15]);
+#endif
+	return 0;
+}
+
+/*
+ * configure IPv6 interface address.  XXX code duplicated with in.c
+ */
+static int
+in6_ifattach_addaddr(ifp, ia)
+	struct ifnet *ifp;
+	struct in6_ifaddr *ia;
+{
+	struct in6_ifaddr *oia;
+	struct ifaddr *ifa;
+	int error;
+	int rtflag;
+	struct in6_addr llsol;
+
+	/*
+	 * initialize if_addrlist, if we are the very first one
+	 */
+	ifa = TAILQ_FIRST(&ifp->if_addrlist);
+	if (ifa == NULL) {
+		TAILQ_INIT(&ifp->if_addrlist);
+	}
+
+	/*
+	 * link the interface address to global list
+	 */
+	TAILQ_INSERT_TAIL(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
+	ia->ia_ifa.ifa_refcnt++;
+
+	/*
+	 * Also link into the IPv6 address chain beginning with in6_ifaddr.
+	 * kazu opposed it, but itojun & jinmei wanted.
+	 */
+	if ((oia = in6_ifaddr) != NULL) {
+		for (; oia->ia_next; oia = oia->ia_next)
+			continue;
+		oia->ia_next = ia;
+	} else
+		in6_ifaddr = ia;
+	ia->ia_ifa.ifa_refcnt++;
+
+	/*
+	 * give the interface a chance to initialize, in case this
+	 * is the first address to be added.
+	 */
+	if (ifp->if_ioctl != NULL) {
+		int s;
+		s = splimp();
+		error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia);
+		splx(s);
+	} else
+		error = 0;
+	if (error) {
+		switch (error) {
+		case EAFNOSUPPORT:
+			printf("%s: IPv6 not supported\n", if_name(ifp));
+			break;
+		default:
+			printf("%s: SIOCSIFADDR error %d\n", if_name(ifp),
+			    error);
+			break;
+		}
+
+		/* undo changes */
+		TAILQ_REMOVE(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
+		IFAFREE(&ia->ia_ifa);
+		if (oia)
+			oia->ia_next = ia->ia_next;
+		else
+			in6_ifaddr = ia->ia_next;
+		IFAFREE(&ia->ia_ifa);
+		return -1;
+	}
+
+	/* configure link-layer address resolution */
+	rtflag = 0;
+	if (IN6_ARE_ADDR_EQUAL(&ia->ia_prefixmask.sin6_addr, &in6mask128))
+		rtflag = RTF_HOST;
+	else {
+		switch (ifp->if_type) {
+		case IFT_LOOP:
+#ifdef IFT_STF
+		case IFT_STF:
+#endif
+			rtflag = 0;
+			break;
+		default:
+			ia->ia_ifa.ifa_rtrequest = nd6_rtrequest;
+			ia->ia_ifa.ifa_flags |= RTF_CLONING;
+			rtflag = RTF_CLONING;
+			break;
+		}
+	}
+
+	/* add route to the interface. */
+	rtrequest(RTM_ADD,
+		  (struct sockaddr *)&ia->ia_addr,
+		  (struct sockaddr *)&ia->ia_addr,
+		  (struct sockaddr *)&ia->ia_prefixmask,
+		  RTF_UP | rtflag,
+		  (struct rtentry **)0);
+	ia->ia_flags |= IFA_ROUTE;
+
+	if ((rtflag & RTF_CLONING) != 0 &&
+	    (ifp->if_flags & IFF_MULTICAST) != 0) {
+		/* Restore saved multicast addresses (if any). */
+		in6_restoremkludge(ia, ifp);
+
+		/*
+		 * join solicited multicast address
+		 */
+		bzero(&llsol, sizeof(llsol));
+		llsol.s6_addr16[0] = htons(0xff02);
+		llsol.s6_addr16[1] = htons(ifp->if_index);
+		llsol.s6_addr32[1] = 0;
+		llsol.s6_addr32[2] = htonl(1);
+		llsol.s6_addr32[3] = ia->ia_addr.sin6_addr.s6_addr32[3];
+		llsol.s6_addr8[12] = 0xff;
+		(void)in6_addmulti(&llsol, ifp, &error);
+
+		/* XXX should we run DAD on other interface types? */
+		switch (ifp->if_type) {
+#if 1
+		case IFT_ARCNET:
+		case IFT_ETHER:
+		case IFT_FDDI:
+#else
+		default:
+#endif
+			/* mark the address TENTATIVE, if needed. */
+			ia->ia6_flags |= IN6_IFF_TENTATIVE;
+			/* nd6_dad_start() will be called in in6_if_up */
+		}
+	}
+
+	return 0;
+}
+
+static int
+in6_ifattach_linklocal(ifp, altifp)
+	struct ifnet *ifp;
+	struct ifnet *altifp;	/*secondary EUI64 source*/
+{
+	struct in6_ifaddr *ia;
+
+	/*
+	 * configure link-local address
+	 */
+	ia = (struct in6_ifaddr *)malloc(sizeof(*ia), M_IFADDR, M_WAITOK);
+	bzero((caddr_t)ia, sizeof(*ia));
+	ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
+	if (ifp->if_flags & IFF_POINTOPOINT)
+		ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
+	else
+		ia->ia_ifa.ifa_dstaddr = NULL;
+	ia->ia_ifa.ifa_netmask = (struct sockaddr *)&ia->ia_prefixmask;
+	ia->ia_ifp = ifp;
+
+	bzero(&ia->ia_prefixmask, sizeof(ia->ia_prefixmask));
+	ia->ia_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
+	ia->ia_prefixmask.sin6_family = AF_INET6;
+	ia->ia_prefixmask.sin6_addr = in6mask64;
+
+	/* just in case */
+	bzero(&ia->ia_dstaddr, sizeof(ia->ia_dstaddr));
+	ia->ia_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
+	ia->ia_dstaddr.sin6_family = AF_INET6;
+
+	bzero(&ia->ia_addr, sizeof(ia->ia_addr));
+	ia->ia_addr.sin6_len = sizeof(struct sockaddr_in6);
+	ia->ia_addr.sin6_family = AF_INET6;
+	ia->ia_addr.sin6_addr.s6_addr16[0] = htons(0xfe80);
+	ia->ia_addr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
+	ia->ia_addr.sin6_addr.s6_addr32[1] = 0;
+	if (ifp->if_flags & IFF_LOOPBACK) {
+		ia->ia_addr.sin6_addr.s6_addr32[2] = 0;
+		ia->ia_addr.sin6_addr.s6_addr32[3] = htonl(1);
 	} else {
-#ifdef DEBUG
-		printf("in6_ifattach_getifid: failed to get EUI64");
+		if (get_ifid(ifp, altifp, &ia->ia_addr.sin6_addr) != 0) {
+#ifdef ND6_DEBUG
+			printf("%s: no ifid available\n", if_name(ifp));
 #endif
-		return EADDRNOTAVAIL;
+			free(ia, M_IFADDR);
+			return -1;
+		}
+	}
+
+	ia->ia_ifa.ifa_metric = ifp->if_metric;
+
+	if (in6_ifattach_addaddr(ifp, ia) != 0) {
+		/* ia will be freed on failure */
+		return -1;
+	}
+
+	return 0;
+}
+
+static int
+in6_ifattach_loopback(ifp)
+	struct ifnet *ifp;	/* must be IFT_LOOP */
+{
+	struct in6_ifaddr *ia;
+
+	/*
+	 * configure link-local address
+	 */
+	ia = (struct in6_ifaddr *)malloc(sizeof(*ia), M_IFADDR, M_WAITOK);
+	bzero((caddr_t)ia, sizeof(*ia));
+	ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
+	ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
+	ia->ia_ifa.ifa_netmask = (struct sockaddr *)&ia->ia_prefixmask;
+	ia->ia_ifp = ifp;
+
+	bzero(&ia->ia_prefixmask, sizeof(ia->ia_prefixmask));
+	ia->ia_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
+	ia->ia_prefixmask.sin6_family = AF_INET6;
+	ia->ia_prefixmask.sin6_addr = in6mask128;
+
+	/*
+	 * Always initialize ia_dstaddr (= broadcast address) to loopback
+	 * address, to make getifaddr happier.
+	 *
+	 * For BSDI, it is mandatory.  The BSDI version of
+	 * ifa_ifwithroute() rejects to add a route to the loopback
+	 * interface.  Even for other systems, loopback looks somewhat
+	 * special.
+	 */
+	bzero(&ia->ia_dstaddr, sizeof(ia->ia_dstaddr));
+	ia->ia_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
+	ia->ia_dstaddr.sin6_family = AF_INET6;
+	ia->ia_dstaddr.sin6_addr = in6addr_loopback;
+
+	bzero(&ia->ia_addr, sizeof(ia->ia_addr));
+	ia->ia_addr.sin6_len = sizeof(struct sockaddr_in6);
+	ia->ia_addr.sin6_family = AF_INET6;
+	ia->ia_addr.sin6_addr = in6addr_loopback;
+
+	ia->ia_ifa.ifa_metric = ifp->if_metric;
+
+	if (in6_ifattach_addaddr(ifp, ia) != 0) {
+		/* ia will be freed on failure */
+		return -1;
 	}
+
+	return 0;
 }
 
 /*
  * XXX multiple loopback interface needs more care.  for instance,
  * nodelocal address needs to be configured onto only one of them.
+ * XXX multiple link-local address case
  */
 void
-in6_ifattach(ifp, type, laddr, noloop)
+in6_ifattach(ifp, altifp)
 	struct ifnet *ifp;
-	u_int type;
-	caddr_t laddr;
-	/* size_t laddrlen; */
-	int noloop;
+	struct ifnet *altifp;	/* secondary EUI64 source */
 {
 	static size_t if_indexlim = 8;
 	struct sockaddr_in6 mltaddr;
 	struct sockaddr_in6 mltmask;
 	struct sockaddr_in6 gate;
 	struct sockaddr_in6 mask;
-	struct in6_ifaddr *ia, *ib, *oia;
-	struct ifaddr *ifa;
-	int rtflag = 0;
-
-	if (type == IN6_IFT_P2P && found_first_ifid == 0) {
-		printf("%s: no ifid available for IPv6 link-local address\n",
-			if_name(ifp));
-#if 0
-		return;
-#else
-		/* last resort */
-		if (gen_rand_eui64(first_ifid) == 0) {
-			printf("%s: using random value as EUI64: "
-				"%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
-				if_name(ifp),
-				first_ifid[0], first_ifid[1],
-				first_ifid[2], first_ifid[3],
-				first_ifid[4], first_ifid[5],
-				first_ifid[6], first_ifid[7]);
-			/*
-			 * invert u bit to convert EUI64 to RFC2373 interface
-			 * ID.
-			 */
-			first_ifid[0] ^= 0x02;
-
-			found_first_ifid = 1;
-		}
-#endif
-	}
-
-	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
-		printf("%s: not multicast capable, IPv6 not enabled\n",
-			if_name(ifp));
-		return;
-	}
+	struct in6_ifaddr *ia;
+	struct in6_addr in6;
 
 	/*
 	 * We have some arrays that should be indexed by if_index.
@@ -281,8 +592,8 @@ in6_ifattach(ifp, type, laddr, noloop)
 	 *	struct in6_ifstat **in6_ifstat
 	 *	struct icmp6_ifstat **icmp6_ifstat
 	 */
-	if (in6_ifstat == NULL || icmp6_ifstat == NULL
-	 || if_index >= if_indexlim) {
+	if (in6_ifstat == NULL || icmp6_ifstat == NULL ||
+	    if_index >= if_indexlim) {
 		size_t n;
 		caddr_t q;
 		size_t olim;
@@ -317,155 +628,49 @@ in6_ifattach(ifp, type, laddr, noloop)
 	}
 
 	/*
-	 * To prevent to assign link-local address to PnP network
-	 * cards multiple times. 
-	 * This is lengthy for P2P and LOOP but works.
+	 * quirks based on interface type
 	 */
-	ifa = TAILQ_FIRST(&ifp->if_addrlist);
-	if (ifa != NULL) {
-		for ( ; ifa; ifa = TAILQ_NEXT(ifa, ifa_list)) {
-			if (ifa->ifa_addr->sa_family != AF_INET6)
-				continue;
-			if (IN6_IS_ADDR_LINKLOCAL(&satosin6(ifa->ifa_addr)->sin6_addr))
-				return;
-		}
-	} else {
-		TAILQ_INIT(&ifp->if_addrlist);
+	switch (ifp->if_type) {
+#ifdef IFT_STF
+	case IFT_STF:
+		/*
+		 * 6to4 interface is a very speical kind of beast.
+		 * no multicast, no linklocal (based on 03 draft).
+		 */
+		goto statinit;
+#endif
+	default:
+		break;
 	}
 
 	/*
-	 * link-local address
+	 * usually, we require multicast capability to the interface
 	 */
-	ia = (struct in6_ifaddr *)malloc(sizeof(*ia), M_IFADDR, M_WAITOK);
-	bzero((caddr_t)ia, sizeof(*ia));
-	ia->ia_ifa.ifa_addr =    (struct sockaddr *)&ia->ia_addr;
-	if (ifp->if_flags & IFF_POINTOPOINT)
-		ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
-	else
-		ia->ia_ifa.ifa_dstaddr = NULL;
-	ia->ia_ifa.ifa_netmask = (struct sockaddr *)&ia->ia_prefixmask;
-	ia->ia_ifp = ifp;
-
-	TAILQ_INSERT_TAIL(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
-	ia->ia_ifa.ifa_refcnt++;
+	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
+		printf("%s: not multicast capable, IPv6 not enabled\n",
+		    if_name(ifp));
+		return;
+	}
 
 	/*
-	 * Also link into the IPv6 address chain beginning with in6_ifaddr.
-	 * kazu opposed it, but itojun & jinmei wanted.
+	 * assign link-local address, if there's none 
 	 */
-	if ((oia = in6_ifaddr) != NULL) {
-		for (; oia->ia_next; oia = oia->ia_next)
-			continue;
-		oia->ia_next = ia;
-	} else
-		in6_ifaddr = ia;
-	ia->ia_ifa.ifa_refcnt++;
-
-	ia->ia_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
-	ia->ia_prefixmask.sin6_family = AF_INET6;
-	ia->ia_prefixmask.sin6_addr = in6mask64;
-
-	bzero(&ia->ia_addr, sizeof(struct sockaddr_in6));
-	ia->ia_addr.sin6_len = sizeof(struct sockaddr_in6);
-	ia->ia_addr.sin6_family = AF_INET6;
-	ia->ia_addr.sin6_addr.s6_addr16[0] = htons(0xfe80);
-	ia->ia_addr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
-	ia->ia_addr.sin6_addr.s6_addr32[1] = 0;
-
-	switch (type) {
-	case IN6_IFT_LOOP:
-		ia->ia_addr.sin6_addr.s6_addr32[2] = 0;
-		ia->ia_addr.sin6_addr.s6_addr32[3] = htonl(1);
-		break;
-	case IN6_IFT_802:
-		ia->ia_ifa.ifa_rtrequest = nd6_rtrequest;
-		ia->ia_ifa.ifa_flags |= RTF_CLONING;
-		rtflag = RTF_CLONING;
-		/* fall through */
-	case IN6_IFT_P2P802:
-		if (laddr == NULL)
-			break;
-		/* XXX use laddrlen */
-		if (laddr_to_eui64(&ia->ia_addr.sin6_addr.s6_addr8[8],
-				laddr, 6) != 0) {
-			break;
-		}
-		/* invert u bit to convert EUI64 to RFC2373 interface ID. */
-		ia->ia_addr.sin6_addr.s6_addr8[8] ^= 0x02;
-		if (found_first_ifid == 0)
-			in6_ifattach_getifid(ifp);
-		bzero(&ia->ia_dstaddr, sizeof(struct sockaddr_in6));
-		ia->ia_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
-		ia->ia_dstaddr.sin6_family = AF_INET6;
-		break;
-	case IN6_IFT_P2P:
-		bcopy((caddr_t)first_ifid,
-		      (caddr_t)&ia->ia_addr.sin6_addr.s6_addr8[8],
-		      IFID_LEN);
-		bzero(&ia->ia_dstaddr, sizeof(struct sockaddr_in6));
-		ia->ia_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
-		ia->ia_dstaddr.sin6_family = AF_INET6;
-		break;
-	case IN6_IFT_ARCNET:
-		ia->ia_ifa.ifa_rtrequest = nd6_rtrequest;
-		ia->ia_ifa.ifa_flags |= RTF_CLONING;
-		rtflag = RTF_CLONING;
-		if (laddr == NULL)
-			break;
-
-		/* make non-global IF id out of link-level address */
-		bzero(&ia->ia_addr.sin6_addr.s6_addr8[8], 7);
-		ia->ia_addr.sin6_addr.s6_addr8[15] = *laddr;
-	}
-
-	ia->ia_ifa.ifa_metric = ifp->if_metric;
-
-	if (ifp->if_ioctl != NULL) {
-		int s;
-		int error;
-
-		/*
-		 * give the interface a chance to initialize, in case this
-		 * is the first address to be added.
-		 */
-		s = splimp();
-		error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia);
-		splx(s);
+	ia = in6ifa_ifpforlinklocal(ifp, 0);
+	if (ia == NULL) {
+		if (in6_ifattach_linklocal(ifp, altifp) != 0)
+			return;
+		ia = in6ifa_ifpforlinklocal(ifp, 0);
 
-		if (error) {
-			switch (error) {
-			case EAFNOSUPPORT:
-				printf("%s: IPv6 not supported\n",
-					if_name(ifp));
-				break;
-			default:
-				printf("%s: SIOCSIFADDR error %d\n",
-					if_name(ifp), error);
-				break;
-			}
+		if (ia == NULL) {
+			printf("%s: failed to add link-local address",
+			    if_name(ifp));
 
-			/* undo changes */
-			TAILQ_REMOVE(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
-			IFAFREE(&ia->ia_ifa);
-			if (oia)
-				oia->ia_next = ia->ia_next;
-			else
-				in6_ifaddr = ia->ia_next;
-			IFAFREE(&ia->ia_ifa);
-			return;
+			/* we can't initialize multicasts without link-local */
+			goto statinit;
 		}
 	}
 
-	/* add route to the interface. */
-	rtrequest(RTM_ADD,
-		  (struct sockaddr *)&ia->ia_addr,
-		  (struct sockaddr *)&ia->ia_addr, 
-		  (struct sockaddr *)&ia->ia_prefixmask,
-		  RTF_UP|rtflag,
-		  (struct rtentry **)0);
-	ia->ia_flags |= IFA_ROUTE;
-
-	if (type == IN6_IFT_P2P || type == IN6_IFT_P2P802) {
+	if (ifp->if_flags & IFF_POINTOPOINT) {
 		/*
 		 * route local address to loopback
 		 */
@@ -486,60 +691,30 @@ in6_ifattach(ifp, type, laddr, noloop)
 	}
 
 	/*
-	 * loopback address
+	 * assign loopback address for loopback interface
+	 * XXX multiple loopback interface case
 	 */
-	ib = (struct in6_ifaddr *)NULL;
-	if (type == IN6_IFT_LOOP) {
-		ib = (struct in6_ifaddr *)
-			malloc(sizeof(*ib), M_IFADDR, M_WAITOK);
-		bzero((caddr_t)ib, sizeof(*ib));
-		ib->ia_ifa.ifa_addr = (struct sockaddr *)&ib->ia_addr;
-		ib->ia_ifa.ifa_dstaddr = (struct sockaddr *)&ib->ia_dstaddr;
-		ib->ia_ifa.ifa_netmask = (struct sockaddr *)&ib->ia_prefixmask;
-		ib->ia_ifp = ifp;
-
-		ia->ia_next = ib;
-		TAILQ_INSERT_TAIL(&ifp->if_addrlist, (struct ifaddr *)ib,
-			ifa_list);
-		ib->ia_ifa.ifa_refcnt++;
-
-		ib->ia_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
-		ib->ia_prefixmask.sin6_family = AF_INET6;
-		ib->ia_prefixmask.sin6_addr = in6mask128;
-		ib->ia_addr.sin6_len = sizeof(struct sockaddr_in6);
-		ib->ia_addr.sin6_family = AF_INET6;
-		ib->ia_addr.sin6_addr = in6addr_loopback;
-
-		/*
-		 * Always initialize ia_dstaddr (= broadcast address)
-		 * to loopback address, to make getifaddr happier.
-		 *
-		 * For BSDI, it is mandatory.  The BSDI version of
-		 * ifa_ifwithroute() rejects to add a route to the loopback
-		 * interface.  Even for other systems, loopback looks somewhat
-		 * special.
-		 */
-		ib->ia_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
-		ib->ia_dstaddr.sin6_family = AF_INET6;
-		ib->ia_dstaddr.sin6_addr = in6addr_loopback;
-
-		ib->ia_ifa.ifa_metric = ifp->if_metric;
-
-		rtrequest(RTM_ADD,
-			  (struct sockaddr *)&ib->ia_addr,
-			  (struct sockaddr *)&ib->ia_addr, 
-			  (struct sockaddr *)&ib->ia_prefixmask,
-			  RTF_UP|RTF_HOST,
-			  (struct rtentry **)0);
+	in6 = in6addr_loopback;
+	if (ifp->if_flags & IFF_LOOPBACK) {
+		if (in6ifa_ifpwithaddr(ifp, &in6) == NULL) {
+			if (in6_ifattach_loopback(ifp) != 0)
+				return;
+		}
+	}
 
-		ib->ia_flags |= IFA_ROUTE;
+#ifdef DIAGNOSTIC
+	if (!ia) {
+		panic("ia == NULL in in6_ifattach");
+		/*NOTREACHED*/
 	}
+#endif
 
 	/*
 	 * join multicast
 	 */
 	if (ifp->if_flags & IFF_MULTICAST) {
 		int error;	/* not used */
+		struct in6_multi *in6m;
 
 		/* Restore saved multicast addresses(if any). */
 		in6_restoremkludge(ia, ifp);
@@ -557,41 +732,41 @@ in6_ifattach(ifp, type, laddr, noloop)
 		mltaddr.sin6_family = AF_INET6;
 		mltaddr.sin6_addr = in6addr_linklocal_allnodes;
 		mltaddr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
-		rtrequest(RTM_ADD,
-			  (struct sockaddr *)&mltaddr,
-			  (struct sockaddr *)&ia->ia_addr, 
-			  (struct sockaddr *)&mltmask,
-			  RTF_UP|RTF_CLONING,  /* xxx */
-			  (struct rtentry **)0);
-		(void)in6_addmulti(&mltaddr.sin6_addr, ifp, &error);
 
-		if (type == IN6_IFT_LOOP) {
-			/*
-			 * join node-local all-nodes address
-			 */
-			mltaddr.sin6_addr = in6addr_nodelocal_allnodes;
+		IN6_LOOKUP_MULTI(mltaddr.sin6_addr, ifp, in6m);
+		if (in6m == NULL) {
 			rtrequest(RTM_ADD,
 				  (struct sockaddr *)&mltaddr,
-				  (struct sockaddr *)&ib->ia_addr, 
+				  (struct sockaddr *)&ia->ia_addr,
 				  (struct sockaddr *)&mltmask,
-				  RTF_UP,
+				  RTF_UP|RTF_CLONING,  /* xxx */
 				  (struct rtentry **)0);
 			(void)in6_addmulti(&mltaddr.sin6_addr, ifp, &error);
-		} else {
+		}
+
+		if (ifp->if_flags & IFF_LOOPBACK) {
+			in6 = in6addr_loopback;
+			ia = in6ifa_ifpwithaddr(ifp, &in6);
 			/*
-			 * join solicited multicast address
+			 * join node-local all-nodes address, on loopback
 			 */
-			bzero(&llsol, sizeof(llsol));
-			llsol.s6_addr16[0] = htons(0xff02);
-			llsol.s6_addr16[1] = htons(ifp->if_index);
-			llsol.s6_addr32[1] = 0;
-			llsol.s6_addr32[2] = htonl(1);
-			llsol.s6_addr32[3] = ia->ia_addr.sin6_addr.s6_addr32[3];
-			llsol.s6_addr8[12] = 0xff;
-			(void)in6_addmulti(&llsol, ifp, &error);
+			mltaddr.sin6_addr = in6addr_nodelocal_allnodes;
+
+			IN6_LOOKUP_MULTI(mltaddr.sin6_addr, ifp, in6m);
+			if (in6m == NULL && ia != NULL) {
+				rtrequest(RTM_ADD,
+					  (struct sockaddr *)&mltaddr,
+					  (struct sockaddr *)&ia->ia_addr,
+					  (struct sockaddr *)&mltmask,
+					  RTF_UP,
+					  (struct rtentry **)0);
+				(void)in6_addmulti(&mltaddr.sin6_addr, ifp, &error);
+			}
 		}
 	}
 
+statinit:;
+
 	/* update dynamically. */
 	if (in6_maxmtu < ifp->if_mtu)
 		in6_maxmtu = ifp->if_mtu;
@@ -609,29 +784,6 @@ in6_ifattach(ifp, type, laddr, noloop)
 
 	/* initialize NDP variables */
 	nd6_ifattach(ifp);
-
-	/* mark the address TENTATIVE, if needed. */
-	switch (ifp->if_type) {
-	case IFT_ARCNET:
-	case IFT_ETHER:
-	case IFT_FDDI:
-#if 0
-	case IFT_ATM:
-	case IFT_SLIP:
-	case IFT_PPP:
-#endif
-		ia->ia6_flags |= IN6_IFF_TENTATIVE;
-		/* nd6_dad_start() will be called in in6_if_up */
-		break;
-	case IFT_DUMMY:
-	case IFT_GIF:	/*XXX*/
-	case IFT_LOOP:
-	case IFT_FAITH:
-	default:
-		break;
-	}
-
-	return;
 }
 
 /*
@@ -674,7 +826,7 @@ in6_ifdetach(ifp)
 			rtfree(rt);
 			rtrequest(RTM_DELETE,
 				(struct sockaddr *)&ia->ia_addr,
-				(struct sockaddr *)&ia->ia_addr, 
+				(struct sockaddr *)&ia->ia_addr,
 				(struct sockaddr *)&ia->ia_prefixmask,
 				rtflags, (struct rtentry **)0);
 		}
@@ -691,7 +843,7 @@ in6_ifdetach(ifp)
 				ia = ia->ia_next;
 			if (ia->ia_next)
 				ia->ia_next = oia->ia_next;
-#ifdef DEBUG
+#ifdef ND6_DEBUG
 			else
 				printf("%s: didn't unlink in6ifaddr from "
 				    "list\n", if_name(ifp));
diff --git a/sys/netinet6/in6_ifattach.h b/sys/netinet6/in6_ifattach.h
index d7023e7bfd4..6985bc9be33 100644
--- a/sys/netinet6/in6_ifattach.h
+++ b/sys/netinet6/in6_ifattach.h
@@ -1,9 +1,10 @@
-/*	$OpenBSD: in6_ifattach.h,v 1.1 1999/12/08 06:50:21 itojun Exp $	*/
+/*	$OpenBSD: in6_ifattach.h,v 1.2 2000/04/17 04:44:50 itojun Exp $	*/
+/*	$KAME: in6_ifattach.h,v 1.9 2000/04/12 05:35:48 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:
@@ -15,7 +16,7 @@
  * 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
@@ -33,18 +34,8 @@
 #define _NETINET6_IN6_IFATTACH_H_
 
 #ifdef _KERNEL
-extern int found_first_ifid;
-
-int in6_ifattach_getifid __P((struct ifnet *));
-void in6_ifattach_p2p __P((void));
-void in6_ifattach __P((struct ifnet *, u_int, caddr_t, int));
+void in6_ifattach __P((struct ifnet *, struct ifnet *));
 void in6_ifdetach __P((struct ifnet *));
 #endif /* _KERNEL */
 
-#define IN6_IFT_LOOP	1
-#define IN6_IFT_P2P	2
-#define IN6_IFT_802	3
-#define IN6_IFT_P2P802	4
-#define IN6_IFT_ARCNET	5
-
 #endif /* _NETINET6_IN6_IFATTACH_H_ */
diff --git a/sys/netinet6/in6_var.h b/sys/netinet6/in6_var.h
index 20e3637da9b..c76b625ad4a 100644
--- a/sys/netinet6/in6_var.h
+++ b/sys/netinet6/in6_var.h
@@ -1,10 +1,10 @@
-/*	$OpenBSD: in6_var.h,v 1.9 2000/02/28 11:55:22 itojun Exp $	*/
-/*	$KAME: in6_var.h,v 1.29 2000/02/25 05:20:58 itojun Exp $	*/
+/*	$OpenBSD: in6_var.h,v 1.10 2000/04/17 04:44:50 itojun Exp $	*/
+/*	$KAME: in6_var.h,v 1.31 2000/03/25 07:23:46 sumikawa 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:
@@ -16,7 +16,7 @@
  * 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
@@ -189,7 +189,7 @@ struct icmp6_ifstat {
 	u_quad_t ifs6_in_mlddone;
 
 	/*
-	 * Output statistics. We should solve unresolved routing problem...  
+	 * Output statistics. We should solve unresolved routing problem...
 	 */
 	/* ipv6IfIcmpOutMsgs, total # of output messages */
 	u_quad_t ifs6_out_msg;
@@ -365,7 +365,7 @@ struct	in6_rrenumreq {
  */
 #define SIOCSIFDSTADDR_IN6	 _IOW('i', 14, struct in6_ifreq)
 #define SIOCSIFNETMASK_IN6	 _IOW('i', 22, struct in6_ifreq)
-#endif 
+#endif
 
 #define SIOCGIFDSTADDR_IN6	_IOWR('i', 34, struct in6_ifreq)
 #define SIOCGIFNETMASK_IN6	_IOWR('i', 37, struct in6_ifreq)
@@ -395,6 +395,8 @@ struct	in6_rrenumreq {
 #define SIOCSDEFIFACE_IN6	_IOWR('i', 85, struct in6_ndifreq)
 #define SIOCGDEFIFACE_IN6	_IOWR('i', 86, struct in6_ndifreq)
 
+#define SIOCSIFINFO_FLAGS	_IOWR('i', 87, struct in6_ndireq) /* XXX */
+
 #define SIOCSIFPREFIX_IN6	_IOW('i', 100, struct in6_prefixreq) /* set */
 #define SIOCGIFPREFIX_IN6	_IOWR('i', 101, struct in6_prefixreq) /* get */
 #define SIOCDIFPREFIX_IN6	_IOW('i', 102, struct in6_prefixreq) /* del */
diff --git a/sys/netinet6/ip6_input.c b/sys/netinet6/ip6_input.c
index e39d5513e0b..94370a45385 100644
--- a/sys/netinet6/ip6_input.c
+++ b/sys/netinet6/ip6_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip6_input.c,v 1.9 2000/03/22 03:50:35 itojun Exp $	*/
+/*	$OpenBSD: ip6_input.c,v 1.10 2000/04/17 04:44:50 itojun Exp $	*/
 /*	$KAME: ip6_input.c,v 1.72 2000/03/21 09:23:19 itojun Exp $	*/
 
 /*
@@ -182,17 +182,13 @@ static void
 ip6_init2(dummy)
 	void *dummy;
 {
-	int ret;
-
-	/* get EUI64 from somewhere */
-	ret = in6_ifattach_getifid(NULL);
 
 #if 1
 	/*
 	 * to route local address of p2p link to loopback,
 	 * assign loopback address first. 
 	 */
-	in6_ifattach(&loif[0], IN6_IFT_LOOP, NULL, 0);
+	in6_ifattach(&loif[0], NULL);
 #else
 	/* you MUST bring lo0 up manually, in rc script. */
 #endif
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 30f7120001a..ac3bfb845d0 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -1,10 +1,10 @@
-/*	$OpenBSD: nd6.c,v 1.10 2000/04/13 16:27:26 itojun Exp $	*/
-/*	$KAME: nd6.c,v 1.41 2000/02/24 16:34:50 itojun Exp $	*/
+/*	$OpenBSD: nd6.c,v 1.11 2000/04/17 04:44:51 itojun Exp $	*/
+/*	$KAME: nd6.c,v 1.55 2000/04/16 14:08:30 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:
@@ -16,7 +16,7 @@
  * 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
@@ -158,12 +158,18 @@ nd6_ifattach(ifp)
 	}
 
 #define ND nd_ifinfo[ifp->if_index]
+
+	/* don't initialize if called twice */
+	if (ND.linkmtu)
+		return;
+
 	ND.linkmtu = ifindex2ifnet[ifp->if_index]->if_mtu;
 	ND.chlim = IPV6_DEFHLIM;
 	ND.basereachable = REACHABLE_TIME;
 	ND.reachable = ND_COMPUTE_RTIME(ND.basereachable);
 	ND.retrans = RETRANS_TIMER;
 	ND.receivedra = 0;
+	ND.flags = ND6_IFF_PERFORMNUD;
 	nd6_setmtu(ifp);
 #undef ND
 }
@@ -339,7 +345,7 @@ nd6_options(ndopts)
 			 * Unknown options must be silently ignored,
 			 * to accomodate future extension to the protocol.
 			 */
-			log(LOG_INFO,
+			log(LOG_DEBUG,
 			    "nd6_options: unsupported option %d - "
 			    "option ignored\n", nd_opt->nd_opt_type);
 		}
@@ -383,6 +389,8 @@ nd6_timer(ignored_arg)
 		struct ifnet *ifp;
 		struct sockaddr_in6 *dst;
 		struct llinfo_nd6 *next = ln->ln_next;
+		/* XXX: used for the DELAY case only: */
+		struct nd_ifinfo *ndi = NULL;
 
 		if ((rt = ln->ln_rt) == NULL) {
 			ln = next;
@@ -392,6 +400,7 @@ nd6_timer(ignored_arg)
 			ln = next;
 			continue;
 		}
+		ndi = &nd_ifinfo[ifp->if_index];
 		dst = (struct sockaddr_in6 *)rt_key(rt);
 
 		if (ln->ln_expire > time_second) {
@@ -402,6 +411,9 @@ nd6_timer(ignored_arg)
 		/* sanity check */
 		if (!rt)
 			panic("rt=0 in nd6_timer(ln=%p)\n", ln);
+		if (rt->rt_llinfo && (struct llinfo_nd6 *)rt->rt_llinfo != ln)
+			panic("rt_llinfo(%p) is not equal to ln(%p)\n",
+			      rt->rt_llinfo, ln);
 		if (!dst)
 			panic("dst=0 in nd6_timer(ln=%p)\n", ln);
 
@@ -437,19 +449,24 @@ nd6_timer(ignored_arg)
 			if (ln->ln_expire)
 				ln->ln_state = ND6_LLINFO_STALE;
 			break;
-		/* 
+		/*
 		 * ND6_LLINFO_STALE state requires nothing for timer
 		 * routine.
 		 */
 		case ND6_LLINFO_DELAY:
-			ln->ln_asked = 1;
-			ln->ln_state = ND6_LLINFO_PROBE;
-			ln->ln_expire = time_second +
-				nd_ifinfo[ifp->if_index].retrans / 1000;
-			nd6_ns_output(ifp, &dst->sin6_addr, &dst->sin6_addr,
-				ln, 0);
+			if (ndi && (ndi->flags & ND6_IFF_PERFORMNUD) != 0) {
+				/* We need NUD */
+				ln->ln_asked = 1;
+				ln->ln_state = ND6_LLINFO_PROBE;
+				ln->ln_expire = time_second +
+					ndi->retrans / 1000;
+				nd6_ns_output(ifp, &dst->sin6_addr,
+					      &dst->sin6_addr,
+					      ln, 0);
+			}
+			else
+				ln->ln_state = ND6_LLINFO_STALE; /* XXX */
 			break;
-
 		case ND6_LLINFO_PROBE:
 			if (ln->ln_asked < nd6_umaxtries) {
 				ln->ln_asked++;
@@ -639,7 +656,7 @@ nd6_lookup(addr6, create, ifp)
 	if (rt && (rt->rt_flags & RTF_LLINFO) == 0) {
 		/*
 		 * This is the case for the default route.
-		 * If we want to create a neighbor cache for the address, we 
+		 * If we want to create a neighbor cache for the address, we
 		 * should free the route for the destination and allocate an
 		 * interface route.
 		 */
@@ -650,6 +667,8 @@ nd6_lookup(addr6, create, ifp)
 	}
 	if (!rt) {
 		if (create && ifp) {
+			int e;
+
 			/*
 			 * If no route is available and create is set,
 			 * we allocate a host route for the destination
@@ -666,17 +685,19 @@ nd6_lookup(addr6, create, ifp)
 			 * Create a new route. RTF_LLINFO is necessary
 			 * to create a Neighbor Cache entry for the
 			 * destination in nd6_rtrequest which will be
-			 * called in rtequest via ifa->ifa_rtrequest. 
+			 * called in rtequest via ifa->ifa_rtrequest.
 			 */
-			if (rtrequest(RTM_ADD, (struct sockaddr *)&sin6,
-				      ifa->ifa_addr,
-				      (struct sockaddr *)&all1_sa,
-				      (ifa->ifa_flags |
-				       RTF_HOST | RTF_LLINFO) & ~RTF_CLONING,
-				      &rt))
+			if ((e = rtrequest(RTM_ADD, (struct sockaddr *)&sin6,
+					   ifa->ifa_addr,
+					   (struct sockaddr *)&all1_sa,
+					   (ifa->ifa_flags |
+					    RTF_HOST | RTF_LLINFO) &
+					   ~RTF_CLONING,
+					   &rt)) != 0)
 				log(LOG_ERR,
 				    "nd6_lookup: failed to add route for a "
-				    "neighbor(%s)\n", ip6_sprintf(addr6));
+				    "neighbor(%s), errno=%d\n",
+				    ip6_sprintf(addr6), e);
 			if (rt == NULL)
 				return(NULL);
 			if (rt->rt_llinfo) {
@@ -711,7 +732,7 @@ nd6_lookup(addr6, create, ifp)
 
 /*
  * Detect if a given IPv6 address identifies a neighbor on a given link.
- * XXX: should take care of the destination of a p2p link? 
+ * XXX: should take care of the destination of a p2p link?
  */
 int
 nd6_is_addr_neighbor(addr, ifp)
@@ -1058,14 +1079,21 @@ nd6_rtrequest(req, rt, sa)
 #endif
 		/* FALLTHROUGH */
 	case RTM_RESOLVE:
-		if (gate->sa_family != AF_LINK ||
-		    gate->sa_len < sizeof(null_sdl)) {
-			log(LOG_DEBUG, "nd6_rtrequest: bad gateway value\n");
-			break;
+		if ((ifp->if_flags & IFF_POINTOPOINT) == 0) {
+			/*
+			 * Address resolution isn't necessary for a point to
+			 * point link, so we can skip this test for a p2p link.
+			 */
+			if (gate->sa_family != AF_LINK ||
+			    gate->sa_len < sizeof(null_sdl)) {
+				log(LOG_DEBUG,
+				    "nd6_rtrequest: bad gateway value\n");
+				break;
+			}
+			SDL(gate)->sdl_type = ifp->if_type;
+			SDL(gate)->sdl_index = ifp->if_index;
 		}
-		SDL(gate)->sdl_type = ifp->if_type;
-		SDL(gate)->sdl_index = ifp->if_index;
-		if (ln != 0)
+		if (ln != NULL)
 			break;	/* This happens on a route change */
 		/*
 		 * Case 2: This route may come from cloning, or a manual route
@@ -1090,7 +1118,7 @@ nd6_rtrequest(req, rt, sa)
 			 */
 			ln->ln_state = ND6_LLINFO_REACHABLE;
 		} else {
-		        /* 
+		        /*
 			 * When req == RTM_RESOLVE, rt is created and
 			 * initialized in rtrequest(), so rt_expire is 0.
 			 */
@@ -1364,6 +1392,10 @@ nd6_ioctl(cmd, data, ifp)
 	case SIOCGIFINFO_IN6:
 		ndi->ndi = nd_ifinfo[ifp->if_index];
 		break;
+	case SIOCSIFINFO_FLAGS:
+		/* XXX: almost all other fields of ndi->ndi is unused */
+		nd_ifinfo[ifp->if_index].flags = ndi->ndi.flags;
+		break;
 	case SIOCSNDFLUSH_IN6:	/* XXX: the ioctl name is confusing... */
 		/* flush default router list */
 		/*
@@ -1585,7 +1617,7 @@ fail:
 				nd6_output(ifp, ln->ln_hold,
 					   (struct sockaddr_in6 *)rt_key(rt),
 					   rt);
-#endif 
+#endif
 				ln->ln_hold = 0;
 			}
 		} else if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
@@ -1634,9 +1666,8 @@ fail:
 	case ND_REDIRECT:
 		/*
 		 * If the icmp is a redirect to a better router, always set the
-		 * is_router flag. Otherwise, if the entry is newly created, 
+		 * is_router flag. Otherwise, if the entry is newly created,
 		 * clear the flag. [RFC 2461, sec 8.3]
-		 * 
 		 */
 		if (code == ND_REDIRECT_ROUTER)
 			ln->ln_router = 1;
@@ -1708,19 +1739,27 @@ nd6_output(ifp, m0, dst, rt0)
 
 	/*
 	 * XXX: we currently do not make neighbor cache on any interface
-	 * other than ARCnet, Ethernet and FDDI.
+	 * other than ARCnet, Ethernet, FDDI and GIF.
+	 *
+	 * draft-ietf-ngtrans-mech-04.txt says:
+	 * - unidirectional tunnels needs no ND
 	 */
 	switch (ifp->if_type) {
 	case IFT_ARCNET:
 	case IFT_ETHER:
 	case IFT_FDDI:
+	case IFT_GIF:		/* XXX need more cases? */
 		break;
 	default:
 		goto sendpkt;
 	}
 
+	if ((ifp->if_flags & IFF_POINTOPOINT) != 0 &&
+	    (nd_ifinfo[ifp->if_index].flags & ND6_IFF_PERFORMNUD) == 0)
+		goto sendpkt;
+
 	/*
-	 * next hop determination. This routine is derived from ether_outpout. 
+	 * next hop determination. This routine is derived from ether_outpout.
 	 */
 	if (rt) {
 		if ((rt->rt_flags & RTF_UP) == 0) {
@@ -1730,7 +1769,7 @@ nd6_output(ifp, m0, dst, rt0)
 				rt->rt_refcnt--;
 				if (rt->rt_ifp != ifp)
 					return nd6_output(ifp, m0, dst, rt); /* XXX: loop care? */
-			} else 
+			} else
 				senderr(EHOSTUNREACH);
 		}
 		if (rt->rt_flags & RTF_GATEWAY) {
@@ -1768,6 +1807,10 @@ nd6_output(ifp, m0, dst, rt0)
 		senderr(EIO);	/* XXX: good error? */
 	}
 
+	/* We don't have to do link-layer address resolution on a p2p link. */
+	if ((ifp->if_flags & IFF_POINTOPOINT) != 0 &&
+	    ln->ln_state < ND6_LLINFO_REACHABLE)
+		ln->ln_state = ND6_LLINFO_STALE;
 
 	/*
 	 * The first time we send a packet to a neighbor whose entry is
@@ -1818,7 +1861,7 @@ nd6_output(ifp, m0, dst, rt0)
 	
   sendpkt:
 	return((*ifp->if_output)(ifp, m, (struct sockaddr *)dst, rt));
-	
+
   bad:
 	if (m)
 		m_freem(m);
diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h
index 1051468ccff..71ff81a8ce2 100644
--- a/sys/netinet6/nd6.h
+++ b/sys/netinet6/nd6.h
@@ -1,10 +1,10 @@
-/*	$OpenBSD: nd6.h,v 1.4 2000/02/28 11:55:22 itojun Exp $	*/
-/*	$KAME: nd6.h,v 1.16 2000/02/24 16:34:51 itojun Exp $	*/
+/*	$OpenBSD: nd6.h,v 1.5 2000/04/17 04:44:51 itojun Exp $	*/
+/*	$KAME: nd6.h,v 1.19 2000/03/25 07:23:57 sumikawa 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:
@@ -16,7 +16,7 @@
  * 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
@@ -67,11 +67,14 @@ struct nd_ifinfo {
 	u_int32_t basereachable;	/* BaseReachableTime */
 	u_int32_t reachable;		/* Reachable Time */
 	u_int32_t retrans;		/* Retrans Timer */
+	u_int32_t flags;		/* Flags */
 	int recalctm;			/* BaseReacable re-calculation timer */
 	u_int8_t chlim;			/* CurHopLimit */
 	u_int8_t receivedra;
 };
 
+#define ND6_IFF_PERFORMNUD	0x1
+
 struct in6_nbrinfo {
 	char ifname[IFNAMSIZ];	/* if name, e.g. "en0" */
 	struct in6_addr addr;	/* IPv6 address of the neighbor */
diff --git a/usr.sbin/ndp/ndp.8 b/usr.sbin/ndp/ndp.8
index 70282196a97..3ffcf015ec4 100644
--- a/usr.sbin/ndp/ndp.8
+++ b/usr.sbin/ndp/ndp.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ndp.8,v 1.6 2000/04/12 21:47:55 aaron Exp $
+.\"	$OpenBSD: ndp.8,v 1.7 2000/04/17 04:44:51 itojun Exp $
 .\"
 .\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 .\" All rights reserved.
@@ -27,7 +27,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"     KAME Id: ndp.8,v 1.5 2000/02/17 05:35:56 itojun Exp
+.\"     KAME Id: ndp.8,v 1.9 2000/04/16 15:17:33 itojun Exp
 .\"
 .Dd May 17, 1998
 .Dt NDP 8
@@ -63,6 +63,7 @@
 .Nm ndp
 .Fl i
 .Ar interface
+.Op Ar flags...
 .Nm ndp
 .Fl p
 .Nm ndp
@@ -105,18 +106,33 @@ Harmonize consistency between the routing table and the default router
 list; install the top entry of the list into the kernel routing table.
 .It Fl I Op delete \(ba Ar interface
 Shows or specifies the default interface used as the default route when
-there is no default router.
-If no argument is given to the option,
-the current deafult interface will be shown.
+there is no default router. If no argument is given to the option,
+the current default interface will be shown.
 If an
 .Ar interface
 is specified, the interface will be used as the default.
 If a special keyword
 .Ic delete
 is specified, the current default interface will be deleted from the kernel.
-.It Fl i
-.Ar interface
-view ND information for specified interface.
+.It Fl i Ar interface Op Ar flags...
+View ND information for the specified interface.
+If additional arguments
+.Ar flags
+are given,
+.Nm
+sets or clears the specified flags for the interface.
+Possible flags are as follows. All of the flags can begin with the
+special character
+.Ql - ,
+which means the flag should be cleared.
+.\"
+.Bl -tag -width Ds -compact
+.It Xo
+.Ic nud
+.Xc
+turn on or off NUD (Neighbor Unreachability Detection) on the
+interface. NUD is usually turned on by default.
+.El
 .It Fl l
 Do not truncate numeric IPv6 address.
 .It Fl n
diff --git a/usr.sbin/ndp/ndp.c b/usr.sbin/ndp/ndp.c
index e02383d527a..cdf24ffc974 100644
--- a/usr.sbin/ndp/ndp.c
+++ b/usr.sbin/ndp/ndp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ndp.c,v 1.4 2000/02/28 11:56:41 itojun Exp $	*/
+/*	$OpenBSD: ndp.c,v 1.5 2000/04/17 04:44:51 itojun Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996, 1997, 1998, and 1999 WIDE Project.
@@ -150,7 +150,7 @@ static char *ether_str __P((struct sockaddr_dl *));
 int ndp_ether_aton __P((char *, u_char *));
 void usage __P((void));
 int rtmsg __P((int));
-void ifinfo __P((char *));
+void ifinfo __P((int, char **));
 void rtrlist __P((void));
 void plist __P((void));
 void pfx_flush __P((void));
@@ -200,9 +200,11 @@ main(argc, argv)
 			/*NOTREACHED*/
 #endif
 		case 'i' :
-			if (argc != 3)
+			argc -= optind;
+			argv += optind;
+			if (argc < 1)
 				usage();
-			ifinfo(argv[2]);
+			ifinfo(argc, argv);
 			exit(0);
 		case 'n':
 			nflag = 1;
@@ -484,12 +486,16 @@ delete(host)
 	if (IN6_ARE_ADDR_EQUAL(&sin->sin6_addr, &sin_m.sin6_addr)) {
 		if (sdl->sdl_family == AF_LINK &&
 		    (rtm->rtm_flags & RTF_LLINFO) &&
-		    !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
-		case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
-		case IFT_ISO88024: case IFT_ISO88025:
-			goto delete;
+		    !(rtm->rtm_flags & RTF_GATEWAY)) {
+			switch (sdl->sdl_type) {
+			case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
+			case IFT_ISO88024: case IFT_ISO88025:
+				goto delete;
+			}
 		}
 	}
+	return 0;
+
 delete:
 	if (sdl->sdl_family != AF_LINK) {
 		printf("cannot locate %s\n", host);
@@ -692,7 +698,7 @@ getnbrinfo(addr, ifindex, warning)
 	nbi.addr = *addr;
 	if (ioctl(s, SIOCGNBRINFO_IN6, (caddr_t)&nbi) < 0) {
 		if (warning)
-			warn("ioctl");
+			warn("ioctl(SIOCGNBRINFO_IN6)");
 		close(s);
 		return(NULL);
 	}
@@ -747,7 +753,7 @@ usage()
 	printf("       ndp -c[nt]\n");
 	printf("       ndp -d[nt] hostname\n");
 	printf("       ndp -f[nt] filename\n");
-	printf("       ndp -i interface\n");
+	printf("       ndp -i interface [flags...]\n");
 #ifdef SIOCSDEFIFACE_IN6
 	printf("       ndp -I [interface|delete]\n");
 #endif
@@ -824,11 +830,14 @@ doit:
 }
 
 void
-ifinfo(ifname)
-	char *ifname;
+ifinfo(argc, argv)
+	int argc;
+	char **argv;
 {
 	struct in6_ndireq nd;
-	int s;
+	int i, s;
+	char *ifname = argv[0];
+	u_int32_t newflags;
 
 	if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
 		perror("ndp: socket");
@@ -841,13 +850,49 @@ ifinfo(ifname)
  		exit(1);
  	}
 #define ND nd.ndi
+	newflags = ND.flags;
+	for (i = 1; i < argc; i++) {
+		int clear = 0;
+		char *cp = argv[i];
+
+		if (*cp == '-') {
+			clear = 1;
+			cp++;
+		}
+
+#define SETFLAG(s, f) \
+	do {\
+		if (strcmp(cp, (s)) == 0) {\
+			if (clear)\
+				newflags &= ~(f);\
+			else\
+				newflags |= (f);\
+		}\
+	} while (0)
+		SETFLAG("nud", ND6_IFF_PERFORMNUD);
+
+		ND.flags = newflags;
+		if (ioctl(s, SIOCSIFINFO_FLAGS, (caddr_t)&nd) < 0) {
+			perror("ioctl(SIOCSIFINFO_FLAGS)");
+			exit(1);
+		}
+#undef SETFLAG
+	}
+
 	printf("linkmtu=%d", ND.linkmtu);
 	printf(", curhlim=%d", ND.chlim);
 	printf(", basereachable=%ds%dms",
 	       ND.basereachable / 1000, ND.basereachable % 1000);
 	printf(", reachable=%ds", ND.reachable);
-	printf(", retrans=%ds%dms\n", ND.retrans / 1000, ND.retrans % 1000);
+	printf(", retrans=%ds%dms", ND.retrans / 1000, ND.retrans % 1000);
+	if (ND.flags) {
+		printf("\nFlags: ");
+		if ((ND.flags & ND6_IFF_PERFORMNUD) != 0)
+			printf("PERFORMNUD ");
+	}
+	putc('\n', stdout);
 #undef ND
+	
 	close(s);
 }