diff --git a/sys/netinet/in.c b/sys/netinet/in.c
index c91df4a2744..9edd74768cb 100644
--- a/sys/netinet/in.c
+++ b/sys/netinet/in.c
@@ -234,16 +234,42 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 	 * in_lifaddr_ioctl() and ifp->if_ioctl().
 	 */
 	switch (cmd) {
-	case SIOCAIFADDR:
-	case SIOCDIFADDR:
 	case SIOCGIFADDR:
 	case SIOCGIFBRDADDR:
 	case SIOCGIFDSTADDR:
 	case SIOCGIFNETMASK:
+	case SIOCDIFADDR:
+		break;
+	case SIOCAIFADDR:
+		/*
+		 * ifra_addr must be present and be of INET family.
+		 * ifra_broadaddr and ifra_mask are optional.
+		 */
+		if (ifra->ifra_addr.sin_len != sizeof(struct sockaddr_in) ||
+		    ifra->ifra_addr.sin_family != AF_INET)
+			return (EINVAL);
+		if (ifra->ifra_broadaddr.sin_len != 0 &&
+		    (ifra->ifra_broadaddr.sin_len != sizeof(struct sockaddr_in) ||
+		    ifra->ifra_broadaddr.sin_family != AF_INET))
+			return (EINVAL);
+#if 0
+		/*
+		 * ifconfig(8) historically doesn't set af_family for mask
+		 * for unknown reason.
+		 */
+		if (ifra->ifra_mask.sin_len != 0 &&
+		    (ifra->ifra_mask.sin_len != sizeof(struct sockaddr_in) ||
+		    ifra->ifra_mask.sin_family != AF_INET))
+			return (EINVAL);
+#endif
+		break;
 	case SIOCSIFADDR:
 	case SIOCSIFBRDADDR:
 	case SIOCSIFDSTADDR:
 	case SIOCSIFNETMASK:
+		if (ifr->ifr_addr.sa_family != AF_INET ||
+		    ifr->ifr_addr.sa_len != sizeof(struct sockaddr_in))
+			return (EINVAL);
 		break;
 
 	case SIOCALIFADDR:
@@ -349,7 +375,7 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 	switch (cmd) {
 	case SIOCAIFADDR:
 	case SIOCDIFADDR:
-		if (ifra->ifra_addr.sin_family == AF_INET) {
+		{
 			struct in_ifaddr *oia;
 
 			IN_IFADDR_RLOCK();
@@ -506,7 +532,7 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 		goto out;
 
 	case SIOCSIFNETMASK:
-		ia->ia_sockmask.sin_addr = ifra->ifra_addr.sin_addr;
+		ia->ia_sockmask = *(struct sockaddr_in *)&ifr->ifr_addr;
 		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr);
 		goto out;
 
@@ -514,14 +540,12 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 		maskIsNew = 0;
 		hostIsNew = 1;
 		error = 0;
-		if (ia->ia_addr.sin_family == AF_INET) {
-			if (ifra->ifra_addr.sin_len == 0) {
-				ifra->ifra_addr = ia->ia_addr;
-				hostIsNew = 0;
-			} else if (ifra->ifra_addr.sin_addr.s_addr ==
-					       ia->ia_addr.sin_addr.s_addr)
-				hostIsNew = 0;
-		}
+		if (ifra->ifra_addr.sin_len == 0) {
+			ifra->ifra_addr = ia->ia_addr;
+			hostIsNew = 0;
+		} else if (ifra->ifra_addr.sin_addr.s_addr ==
+			    ia->ia_addr.sin_addr.s_addr)
+			hostIsNew = 0;
 		if (ifra->ifra_mask.sin_len) {
 			/* 
 			 * QL: XXX
@@ -552,7 +576,7 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 			break;
 
 		if ((ifp->if_flags & IFF_BROADCAST) &&
-		    (ifra->ifra_broadaddr.sin_family == AF_INET))
+		    ifra->ifra_broadaddr.sin_len)
 			ia->ia_broadaddr = ifra->ifra_broadaddr;
 		if (error == 0) {
 			ii = ((struct in_ifinfo *)ifp->if_afdata[AF_INET]);
@@ -608,31 +632,26 @@ in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
 
 	IN_IFADDR_WLOCK();
 	TAILQ_REMOVE(&V_in_ifaddrhead, ia, ia_link);
-	if (ia->ia_addr.sin_family == AF_INET) {
-		struct in_ifaddr *if_ia;
 
-		LIST_REMOVE(ia, ia_hash);
-		IN_IFADDR_WUNLOCK();
-		/*
-		 * If this is the last IPv4 address configured on this
-		 * interface, leave the all-hosts group.
-		 * No state-change report need be transmitted.
-		 */
-		if_ia = NULL;
-		IFP_TO_IA(ifp, if_ia);
-		if (if_ia == NULL) {
-			ii = ((struct in_ifinfo *)ifp->if_afdata[AF_INET]);
-			IN_MULTI_LOCK();
-			if (ii->ii_allhosts) {
-				(void)in_leavegroup_locked(ii->ii_allhosts,
-				    NULL);
-				ii->ii_allhosts = NULL;
-			}
-			IN_MULTI_UNLOCK();
-		} else
-			ifa_free(&if_ia->ia_ifa);
+	LIST_REMOVE(ia, ia_hash);
+	IN_IFADDR_WUNLOCK();
+	/*
+	 * If this is the last IPv4 address configured on this
+	 * interface, leave the all-hosts group.
+	 * No state-change report need be transmitted.
+	 */
+	IFP_TO_IA(ifp, iap);
+	if (iap == NULL) {
+		ii = ((struct in_ifinfo *)ifp->if_afdata[AF_INET]);
+		IN_MULTI_LOCK();
+		if (ii->ii_allhosts) {
+			(void)in_leavegroup_locked(ii->ii_allhosts, NULL);
+			ii->ii_allhosts = NULL;
+		}
+		IN_MULTI_UNLOCK();
 	} else
-		IN_IFADDR_WUNLOCK();
+		ifa_free(&iap->ia_ifa);
+
 	ifa_free(&ia->ia_ifa);				/* in_ifaddrhead */
 out:
 	if (ia != NULL)
@@ -828,50 +847,29 @@ in_ifinit(struct ifnet *ifp, struct in_ifaddr *ia, struct sockaddr_in *sin,
     int scrub)
 {
 	register u_long i = ntohl(sin->sin_addr.s_addr);
-	struct sockaddr_in oldaddr;
 	int flags = RTF_UP, error = 0;
 
-	oldaddr = ia->ia_addr;
-	if (oldaddr.sin_family == AF_INET)
+	if (scrub)
+		in_scrubprefix(ia, LLE_STATIC);
+
+	IN_IFADDR_WLOCK();
+	if (ia->ia_addr.sin_family == AF_INET)
 		LIST_REMOVE(ia, ia_hash);
 	ia->ia_addr = *sin;
-	if (ia->ia_addr.sin_family == AF_INET) {
-		IN_IFADDR_WLOCK();
-		LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
-		    ia, ia_hash);
-		IN_IFADDR_WUNLOCK();
-	}
+	LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
+	    ia, ia_hash);
+	IN_IFADDR_WUNLOCK();
+
 	/*
 	 * Give the interface a chance to initialize
 	 * if this is its first address,
 	 * and to validate the address if necessary.
 	 */
-	if (ifp->if_ioctl != NULL) {
-		error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia);
-		if (error) {
+	if (ifp->if_ioctl != NULL &&
+	    (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia)) != 0)
 			/* LIST_REMOVE(ia, ia_hash) is done in in_control */
-			ia->ia_addr = oldaddr;
-			IN_IFADDR_WLOCK();
-			if (ia->ia_addr.sin_family == AF_INET)
-				LIST_INSERT_HEAD(INADDR_HASH(
-				    ia->ia_addr.sin_addr.s_addr), ia, ia_hash);
-			else 
-				/* 
-				 * If oldaddr family is not AF_INET (e.g. 
-				 * interface has been just created) in_control 
-				 * does not call LIST_REMOVE, and we end up 
-				 * with bogus ia entries in hash
-				 */
-				LIST_REMOVE(ia, ia_hash);
-			IN_IFADDR_WUNLOCK();
 			return (error);
-		}
-	}
-	if (scrub) {
-		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
-		in_ifscrub(ifp, ia, LLE_STATIC);
-		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
-	}
+
 	/*
 	 * Be compatible with network classes, if netmask isn't supplied,
 	 * guess it based on classes.
@@ -916,11 +914,9 @@ in_ifinit(struct ifnet *ifp, struct in_ifaddr *ia, struct sockaddr_in *sin,
 	if (ia->ia_addr.sin_addr.s_addr == INADDR_ANY)
 		return (0);
 
-	if (ifp->if_flags & IFF_POINTOPOINT) {
-		if (ia->ia_dstaddr.sin_addr.s_addr == ia->ia_addr.sin_addr.s_addr)
+	if (ifp->if_flags & IFF_POINTOPOINT &&
+	    ia->ia_dstaddr.sin_addr.s_addr == ia->ia_addr.sin_addr.s_addr)
 			return (0);
-	}
-
 
 	/*
 	 * add a loopback route to self