diff --git a/sys/net/if.c b/sys/net/if.c
index 39dc941..1ce07df 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1593,7 +1593,7 @@ done:
  */
 /*ARGSUSED*/
 struct ifaddr *
-ifa_ifwithdstaddr(struct sockaddr *addr)
+ifa_ifwithdstaddr(const struct sockaddr *addr)
 {
 	struct ifnet *ifp;
 	struct ifaddr *ifa;
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index 41ac056..80b5be6 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -935,7 +935,7 @@ int	ifa_del_loopback_route(struct ifaddr *, struct sockaddr *);
 struct	ifaddr *ifa_ifwithaddr(struct sockaddr *);
 int		ifa_ifwithaddr_check(struct sockaddr *);
 struct	ifaddr *ifa_ifwithbroadaddr(struct sockaddr *);
-struct	ifaddr *ifa_ifwithdstaddr(struct sockaddr *);
+struct	ifaddr *ifa_ifwithdstaddr(const struct sockaddr *);
 struct	ifaddr *ifa_ifwithnet(struct sockaddr *, int);
 struct	ifaddr *ifa_ifwithroute(int, struct sockaddr *, struct sockaddr *);
 struct	ifaddr *ifa_ifwithroute_fib(int, struct sockaddr *, struct sockaddr *, u_int);
diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c
index 12abd0d..e7e96e3 100644
--- a/sys/netinet6/ip6_output.c
+++ b/sys/netinet6/ip6_output.c
@@ -237,6 +237,7 @@ ip6_output(struct mbuf *m0, struct ip6_pktopts *opt,
 	struct route_in6 ip6route;
 	struct rtentry *rt = NULL;
 	struct sockaddr_in6 *dst, src_sa, dst_sa;
+	const struct sockaddr_in6 *gw;
 	struct in6_addr odst;
 	int error = 0;
 	struct in6_ifaddr *ia = NULL;
@@ -519,7 +520,7 @@ skip_ipsec2:;
 	ro_pmtu = ro;
 	if (opt && opt->ip6po_rthdr)
 		ro = &opt->ip6po_route;
-	dst = (struct sockaddr_in6 *)&ro->ro_dst;
+	gw = dst = (struct sockaddr_in6 *)&ro->ro_dst;
 #ifdef FLOWTABLE
 	if (ro->ro_rt == NULL) {
 		struct flentry *fle;
@@ -589,7 +590,7 @@ again:
 
 		m = state.m;
 		ro = (struct route_in6 *)state.ro;
-		dst = (struct sockaddr_in6 *)state.dst;
+		gw = (struct sockaddr_in6 *)state.dst;
 		if (error == EJUSTRETURN) {
 			/*
 			 * We had a SP with a level of 'use' and no SA. We
@@ -636,7 +637,7 @@ again:
 	/* adjust pointer */
 	ip6 = mtod(m, struct ip6_hdr *);
 
-	if (ro->ro_rt && fwd_tag == NULL) {
+	if (ro->ro_rt != NULL && fwd_tag == NULL) {
 		rt = ro->ro_rt;
 		ifp = ro->ro_rt->rt_ifp;
 	} else {
@@ -653,13 +654,13 @@ again:
 				in6_ifstat_inc(ifp, ifs6_out_discard);
 			goto bad;
 		}
-	}
-	if (rt == NULL) {
-		/*
-		 * If in6_selectroute() does not return a route entry,
-		 * dst may not have been updated.
-		 */
-		*dst = dst_sa;	/* XXX */
+		if (rt == NULL) {
+			/*
+			 * If in6_selectroute() does not return a route entry,
+			 * dst may not have been updated.
+			 */
+			*dst = dst_sa;	/* XXX */
+		}
 	}
 
 	/*
@@ -727,10 +728,9 @@ again:
 			 * application.  We assume the next hop is an IPv6
 			 * address.
 			 */
-			dst = (struct sockaddr_in6 *)opt->ip6po_nexthop;
-		}
-		else if ((rt->rt_flags & RTF_GATEWAY))
-			dst = (struct sockaddr_in6 *)rt->rt_gateway;
+			gw = (const struct sockaddr_in6 *)opt->ip6po_nexthop;
+		} else if ((rt->rt_flags & RTF_GATEWAY))
+			gw = (const struct sockaddr_in6 *)rt->rt_gateway;
 	}
 
 	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
@@ -927,7 +927,6 @@ again:
 	/* Or forward to some other address? */
 	if ((m->m_flags & M_IP6_NEXTHOP) &&
 	    (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
-		dst = (struct sockaddr_in6 *)&ro->ro_dst;
 		bcopy((fwd_tag+1), &dst_sa, sizeof(struct sockaddr_in6));
 		m->m_flags |= M_SKIP_FIREWALL;
 		m->m_flags &= ~M_IP6_NEXTHOP;
@@ -1025,7 +1024,7 @@ passout:
 			ia6->ia_ifa.if_obytes += m->m_pkthdr.len;
 			ifa_free(&ia6->ia_ifa);
 		}
-		error = nd6_output(ifp, origifp, m, dst, ro->ro_rt);
+		error = nd6_output(ifp, origifp, m, gw, ro->ro_rt);
 		goto done;
 	}
 
@@ -1179,7 +1178,7 @@ sendorfree:
 				ia->ia_ifa.if_opackets++;
 				ia->ia_ifa.if_obytes += m->m_pkthdr.len;
 			}
-			error = nd6_output(ifp, origifp, m, dst, ro->ro_rt);
+			error = nd6_output(ifp, origifp, m, gw, ro->ro_rt);
 		} else
 			m_freem(m);
 	}
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 0e30825..bc3d115 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -122,7 +122,7 @@ VNET_DEFINE(int, nd6_recalc_reachtm_interval) = ND6_RECALC_REACHTM_INTERVAL;
 
 int	(*send_sendso_input_hook)(struct mbuf *, struct ifnet *, int, int);
 
-static int nd6_is_new_addr_neighbor(struct sockaddr_in6 *,
+static int nd6_is_new_addr_neighbor(const struct sockaddr_in6 *,
 	struct ifnet *);
 static void nd6_setmtu0(struct ifnet *, struct nd_ifinfo *);
 static void nd6_slowtimo(void *);
@@ -824,7 +824,7 @@ nd6_purge(struct ifnet *ifp)
  * Returns the llentry locked
  */
 struct llentry *
-nd6_lookup(struct in6_addr *addr6, int flags, struct ifnet *ifp)
+nd6_lookup(const struct in6_addr *addr6, int flags, struct ifnet *ifp)
 {
 	struct sockaddr_in6 sin6;
 	struct llentry *ln;
@@ -856,7 +856,7 @@ nd6_lookup(struct in6_addr *addr6, int flags, struct ifnet *ifp)
  * to not reenter the routing code from within itself.
  */
 static int
-nd6_is_new_addr_neighbor(struct sockaddr_in6 *addr, struct ifnet *ifp)
+nd6_is_new_addr_neighbor(const struct sockaddr_in6 *addr, struct ifnet *ifp)
 {
 	struct nd_prefix *pr;
 	struct ifaddr *dstaddr;
@@ -929,7 +929,7 @@ nd6_is_new_addr_neighbor(struct sockaddr_in6 *addr, struct ifnet *ifp)
 	 * If the address is assigned on the node of the other side of
 	 * a p2p interface, the address should be a neighbor.
 	 */
-	dstaddr = ifa_ifwithdstaddr((struct sockaddr *)addr);
+	dstaddr = ifa_ifwithdstaddr((const struct sockaddr *)addr);
 	if (dstaddr != NULL) {
 		if (dstaddr->ifa_ifp == ifp) {
 			ifa_free(dstaddr);
@@ -957,7 +957,7 @@ nd6_is_new_addr_neighbor(struct sockaddr_in6 *addr, struct ifnet *ifp)
  * XXX: should take care of the destination of a p2p link?
  */
 int
-nd6_is_addr_neighbor(struct sockaddr_in6 *addr, struct ifnet *ifp)
+nd6_is_addr_neighbor(const struct sockaddr_in6 *addr, struct ifnet *ifp)
 {
 	struct llentry *lle;
 	int rc = 0;
@@ -1808,7 +1808,7 @@ nd6_slowtimo(void *arg)
 
 int
 nd6_output(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
-    struct sockaddr_in6 *dst, struct rtentry *rt0)
+    const struct sockaddr_in6 *dst, struct rtentry *rt0)
 {
 
 	return (nd6_output_lle(ifp, origifp, m0, dst, rt0, NULL, NULL));
@@ -1827,7 +1827,7 @@ nd6_output(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
 
 int
 nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
-    struct sockaddr_in6 *dst, struct rtentry *rt0, struct llentry *lle,
+    const struct sockaddr_in6 *dst, struct rtentry *rt0, struct llentry *lle,
 	struct mbuf **chain)
 {
 	struct mbuf *m = m0;
@@ -1867,7 +1867,8 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
 	if (ln == NULL) {
 	retry:
 		IF_AFDATA_LOCK(ifp);
-		ln = lla_lookup(LLTABLE6(ifp), flags, (struct sockaddr *)dst);
+		ln = lla_lookup(LLTABLE6(ifp), flags,
+		    (const struct sockaddr *)dst);
 		IF_AFDATA_UNLOCK(ifp);
 		if ((ln == NULL) && nd6_is_addr_neighbor(dst, ifp))  {
 			/*
@@ -2063,10 +2064,10 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
 	/* Reset layer specific mbuf flags to avoid confusing lower layers. */
 	m->m_flags &= ~(M_PROTOFLAGS);  
 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
-		return ((*ifp->if_output)(origifp, m, (struct sockaddr *)dst,
-		    NULL));
+		return ((*ifp->if_output)(origifp, m,
+		    (const struct sockaddr *)dst, NULL));
 	}
-	error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst, NULL);
+	error = (*ifp->if_output)(ifp, m, (const struct sockaddr *)dst, NULL);
 	return (error);
 
   bad:
diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h
index 25d8c5d..728734e 100644
--- a/sys/netinet6/nd6.h
+++ b/sys/netinet6/nd6.h
@@ -391,11 +391,11 @@ void nd6_destroy(void);
 #endif
 struct nd_ifinfo *nd6_ifattach(struct ifnet *);
 void nd6_ifdetach(struct nd_ifinfo *);
-int nd6_is_addr_neighbor(struct sockaddr_in6 *, struct ifnet *);
+int nd6_is_addr_neighbor(const struct sockaddr_in6 *, struct ifnet *);
 void nd6_option_init(void *, int, union nd_opts *);
 struct nd_opt_hdr *nd6_option(union nd_opts *);
 int nd6_options(union nd_opts *);
-struct	llentry *nd6_lookup(struct in6_addr *, int, struct ifnet *);
+struct	llentry *nd6_lookup(const struct in6_addr *, int, struct ifnet *);
 void nd6_setmtu(struct ifnet *);
 void nd6_llinfo_settimer(struct llentry *, long);
 void nd6_llinfo_settimer_locked(struct llentry *, long);
@@ -409,9 +409,9 @@ int nd6_ioctl(u_long, caddr_t, struct ifnet *);
 struct llentry *nd6_cache_lladdr(struct ifnet *, struct in6_addr *,
 	char *, int, int, int);
 int nd6_output(struct ifnet *, struct ifnet *, struct mbuf *,
-	struct sockaddr_in6 *, struct rtentry *);
+	const struct sockaddr_in6 *, struct rtentry *);
 int nd6_output_lle(struct ifnet *, struct ifnet *, struct mbuf *,
-	struct sockaddr_in6 *, struct rtentry *, struct llentry *,
+	const struct sockaddr_in6 *, struct rtentry *, struct llentry *,
 	struct mbuf **);
 int nd6_output_flush(struct ifnet *, struct ifnet *, struct mbuf *,
 	struct sockaddr_in6 *, struct route *);