Index: net/if.c
===================================================================
RCS file: /cvs/src/sys/net/if.c,v
retrieving revision 1.547
diff -u -p -r1.547 if.c
--- net/if.c	20 Feb 2018 03:46:45 -0000	1.547
+++ net/if.c	27 Feb 2018 21:40:27 -0000
@@ -1447,16 +1447,17 @@ ifaof_ifpforaddr(struct sockaddr *addr, 
 	return (ifa_maybe);
 }
 
-void
+int
 if_rtrequest_dummy(struct ifnet *ifp, int req, struct rtentry *rt)
 {
+	return (0);
 }
 
 /*
  * Default action when installing a local route on a point-to-point
  * interface.
  */
-void
+int
 p2p_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt)
 {
 	struct ifnet *lo0ifp;
@@ -1497,6 +1498,8 @@ p2p_rtrequest(struct ifnet *ifp, int req
 	default:
 		break;
 	}
+
+	return (0);
 }
 
 
Index: net/if_ethersubr.c
===================================================================
RCS file: /cvs/src/sys/net/if_ethersubr.c,v
retrieving revision 1.251
diff -u -p -r1.251 if_ethersubr.c
--- net/if_ethersubr.c	2 Feb 2018 22:00:39 -0000	1.251
+++ net/if_ethersubr.c	27 Feb 2018 21:40:27 -0000
@@ -162,21 +162,26 @@ ether_ioctl(struct ifnet *ifp, struct ar
 }
 
 
-void
+int
 ether_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt)
 {
+	int error;
+
 	switch (rt_key(rt)->sa_family) {
 	case AF_INET:
-		arp_rtrequest(ifp, req, rt);
+		error = arp_rtrequest(ifp, req, rt);
 		break;
 #ifdef INET6
 	case AF_INET6:
-		nd6_rtrequest(ifp, req, rt);
+		error = nd6_rtrequest(ifp, req, rt);
 		break;
 #endif
 	default:
+		error = 0;
 		break;
 	}
+
+	return (error);
 }
 /*
  * Ethernet output routine.
Index: net/if_loop.c
===================================================================
RCS file: /cvs/src/sys/net/if_loop.c,v
retrieving revision 1.86
diff -u -p -r1.86 if_loop.c
--- net/if_loop.c	10 Feb 2018 05:32:21 -0000	1.86
+++ net/if_loop.c	27 Feb 2018 21:40:27 -0000
@@ -143,7 +143,7 @@
 int	loioctl(struct ifnet *, u_long, caddr_t);
 void	loopattach(int);
 void	loop_delayed_create(void *);
-void	lortrequest(struct ifnet *, int, struct rtentry *);
+int	lortrequest(struct ifnet *, int, struct rtentry *);
 int	loinput(struct ifnet *, struct mbuf *, void *);
 int	looutput(struct ifnet *,
 	    struct mbuf *, struct sockaddr *, struct rtentry *);
@@ -253,11 +253,13 @@ looutput(struct ifnet *ifp, struct mbuf 
 	return (if_output_local(ifp, m, dst->sa_family));
 }
 
-void
+int
 lortrequest(struct ifnet *ifp, int cmd, struct rtentry *rt)
 {
 	if (rt && rt->rt_mtu == 0)
 		rt->rt_mtu = LOMTU;
+
+	return (0);
 }
 
 /*
Index: net/if_var.h
===================================================================
RCS file: /cvs/src/sys/net/if_var.h,v
retrieving revision 1.89
diff -u -p -r1.89 if_var.h
--- net/if_var.h	10 Jan 2018 23:50:39 -0000	1.89
+++ net/if_var.h	27 Feb 2018 21:40:27 -0000
@@ -124,7 +124,7 @@ struct ifnet {				/* and the entries */
 	struct hook_desc_head *if_linkstatehooks; /* [I] link change callbacks*/
 	struct hook_desc_head *if_detachhooks; /* [I] detach callbacks */
 				/* [I] check or clean routes (+ or -)'d */
-	void	(*if_rtrequest)(struct ifnet *, int, struct rtentry *);
+	int	(*if_rtrequest)(struct ifnet *, int, struct rtentry *);
 	char	if_xname[IFNAMSIZ];	/* [I] external name (name + unit) */
 	int	if_pcount;		/* [k] # of promiscuous listeners */
 	caddr_t	if_bpf;			/* packet filter structure */
@@ -317,8 +317,8 @@ void	if_input(struct ifnet *, struct mbu
 void	if_input_process(struct ifnet *, struct mbuf_list *);
 int	if_input_local(struct ifnet *, struct mbuf *, sa_family_t);
 int	if_output_local(struct ifnet *, struct mbuf *, sa_family_t);
-void	if_rtrequest_dummy(struct ifnet *, int, struct rtentry *);
-void	p2p_rtrequest(struct ifnet *, int, struct rtentry *);
+int	if_rtrequest_dummy(struct ifnet *, int, struct rtentry *);
+int	p2p_rtrequest(struct ifnet *, int, struct rtentry *);
 
 struct	ifaddr *ifa_ifwithaddr(struct sockaddr *, u_int);
 struct	ifaddr *ifa_ifwithdstaddr(struct sockaddr *, u_int);
Index: netinet/if_ether.c
===================================================================
RCS file: /cvs/src/sys/netinet/if_ether.c,v
retrieving revision 1.233
diff -u -p -r1.233 if_ether.c
--- netinet/if_ether.c	16 Jan 2018 10:33:55 -0000	1.233
+++ netinet/if_ether.c	27 Feb 2018 21:40:27 -0000
@@ -123,7 +123,7 @@ arptimer(void *arg)
 	NET_UNLOCK();
 }
 
-void
+int
 arp_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt)
 {
 	struct sockaddr *gate = rt->rt_gateway;
@@ -142,7 +142,7 @@ arp_rtrequest(struct ifnet *ifp, int req
 	}
 
 	if (ISSET(rt->rt_flags, RTF_GATEWAY|RTF_BROADCAST|RTF_MULTICAST))
-		return;
+		return (0);
 
 	switch (req) {
 
@@ -222,6 +222,8 @@ arp_rtrequest(struct ifnet *ifp, int req
 			arpinvalidate(rt);
 		break;
 	}
+
+	return (0);
 }
 
 /*
Index: netinet/if_ether.h
===================================================================
RCS file: /cvs/src/sys/netinet/if_ether.h,v
retrieving revision 1.73
diff -u -p -r1.73 if_ether.h
--- netinet/if_ether.h	29 Nov 2016 10:09:57 -0000	1.73
+++ netinet/if_ether.h	27 Feb 2018 21:40:27 -0000
@@ -230,7 +230,7 @@ void	arpwhohas(struct arpcom *, struct i
 int	arpproxy(struct in_addr, unsigned int);
 int	arpresolve(struct ifnet *, struct rtentry *, struct mbuf *,
 	    struct sockaddr *, u_char *);
-void	arp_rtrequest(struct ifnet *, int, struct rtentry *);
+int	arp_rtrequest(struct ifnet *, int, struct rtentry *);
 
 void	ether_fakeaddr(struct ifnet *);
 int	ether_addmulti(struct ifreq *, struct arpcom *);
@@ -242,7 +242,7 @@ int	ether_ioctl(struct ifnet *, struct a
 int	ether_input(struct ifnet *, struct mbuf *, void *);
 int	ether_output(struct ifnet *,
 	    struct mbuf *, struct sockaddr *, struct rtentry *);
-void	ether_rtrequest(struct ifnet *, int, struct rtentry *);
+int	ether_rtrequest(struct ifnet *, int, struct rtentry *);
 char	*ether_sprintf(u_char *);
 
 
Index: netinet6/nd6.c
===================================================================
RCS file: /cvs/src/sys/netinet6/nd6.c,v
retrieving revision 1.223
diff -u -p -r1.223 nd6.c
--- netinet6/nd6.c	15 Jan 2018 13:48:31 -0000	1.223
+++ netinet6/nd6.c	27 Feb 2018 21:40:27 -0000
@@ -778,7 +778,7 @@ out:
 	if_put(ifp);
 }
 
-void
+int
 nd6_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt)
 {
 	struct sockaddr *gate = rt->rt_gateway;
@@ -786,7 +786,7 @@ nd6_rtrequest(struct ifnet *ifp, int req
 	struct ifaddr *ifa;
 
 	if (ISSET(rt->rt_flags, RTF_GATEWAY|RTF_MULTICAST))
-		return;
+		return (0);
 
 	if (nd6_need_cache(ifp) == 0 && (rt->rt_flags & RTF_HOST) == 0) {
 		/*
@@ -796,7 +796,7 @@ nd6_rtrequest(struct ifnet *ifp, int req
 		 * Moreover, the RTF_LLINFO flag which would be set below
 		 * would annoy the ndp(8) command.
 		 */
-		return;
+		return (0);
 	}
 
 	if (req == RTM_RESOLVE && nd6_need_cache(ifp) == 0) {
@@ -815,7 +815,7 @@ nd6_rtrequest(struct ifnet *ifp, int req
 		 * of the destination.
 		 */
 		rt->rt_flags &= ~RTF_LLINFO;
-		return;
+		return (0);
 	}
 
 	switch (req) {
@@ -1006,6 +1006,8 @@ nd6_rtrequest(struct ifnet *ifp, int req
 			nd6_invalidate(rt);
 		break;
 	}
+
+	return (0);
 }
 
 int
Index: netinet6/nd6.h
===================================================================
RCS file: /cvs/src/sys/netinet6/nd6.h,v
retrieving revision 1.74
diff -u -p -r1.74 nd6.h
--- netinet6/nd6.h	27 Nov 2017 15:41:30 -0000	1.74
+++ netinet6/nd6.h	27 Feb 2018 21:40:27 -0000
@@ -173,7 +173,7 @@ void nd6_setmtu(struct ifnet *);
 void nd6_llinfo_settimer(struct llinfo_nd6 *, unsigned int);
 void nd6_purge(struct ifnet *);
 void nd6_nud_hint(struct rtentry *);
-void nd6_rtrequest(struct ifnet *, int, struct rtentry *);
+int nd6_rtrequest(struct ifnet *, int, struct rtentry *);
 int nd6_ioctl(u_long, caddr_t, struct ifnet *);
 void nd6_cache_lladdr(struct ifnet *, struct in6_addr *, char *, int, int, int);
 int nd6_resolve(struct ifnet *, struct rtentry *, struct mbuf *,