Index: sys/net/route.h
===================================================================
--- sys/net/route.h
+++ sys/net/route.h
@@ -455,6 +455,14 @@
 /* New API */
 struct nhop_object *rib_lookup(uint32_t fibnum, const struct sockaddr *dst,
 	    uint32_t flags, uint32_t flowid);
+void rt_get_inet_prefix_plen(const struct rtentry *rt, struct in_addr *paddr,
+	    int *plen);
+void rt_get_inet_prefix_pmask(const struct rtentry *rt, struct in_addr *paddr,
+	    struct in_addr *pmask);
+void rt_get_inet6_prefix_plen(const struct rtentry *rt, struct in6_addr *paddr,
+	    int *plen);
+void rt_get_inet6_prefix_pmask(const struct rtentry *rt, struct in6_addr *paddr,
+	    struct in6_addr *pmask);
 #endif
 
 #endif
Index: sys/net/route/route_ctl.c
===================================================================
--- sys/net/route/route_ctl.c
+++ sys/net/route/route_ctl.c
@@ -236,6 +236,84 @@
 	return (weight);
 }
 
+#ifdef INET
+void
+rt_get_inet_prefix_plen(const struct rtentry *rt, struct in_addr *paddr, int *plen)
+{
+	const struct sockaddr_in *dst;
+
+	dst = (const struct sockaddr_in *)rt_key_const(rt);
+	KASSERT((dst->sin_family == AF_INET),
+	    ("rt family is %d, not inet", dst->sin_family));
+	*paddr = dst->sin_addr;
+	dst = (const struct sockaddr_in *)rt_mask_const(rt);
+	if (dst == NULL)
+		*plen = 32;
+	else
+		*plen = bitcount32(dst->sin_addr.s_addr);
+}
+
+void
+rt_get_inet_prefix_pmask(const struct rtentry *rt, struct in_addr *paddr,
+    struct in_addr *pmask)
+{
+	const struct sockaddr_in *dst;
+
+	dst = (const struct sockaddr_in *)rt_key_const(rt);
+	KASSERT((dst->sin_family == AF_INET),
+	    ("rt family is %d, not inet", dst->sin_family));
+	*paddr = dst->sin_addr;
+	dst = (const struct sockaddr_in *)rt_mask_const(rt);
+	if (dst == NULL)
+		*pmask->s_addr = INADDR_BROADCAST;
+	else
+		*plen = bitcount32(dst->sin_addr.s_addr);
+}
+#endif
+
+#ifdef INET6
+static int
+inet6_get_plen(const struct in6_addr *addr)
+{
+
+	return (bitmask32(addr->s6_addr32[0]) + bitmask32(addr->s6_addr32[1]) +
+	    bitmask32(addr->s6_addr32[2]) + bitmask32(addr->s6_addr32[3]));
+}
+
+void
+rt_get_inet6_prefix_plen(const struct rtentry *rt, struct in6_addr *paddr, int *plen)
+{
+	const struct sockaddr_in6 *dst;
+
+	dst = (const struct sockaddr_in6 *)rt_key_const(rt);
+	KASSERT((dst->sin6_family == AF_INET6),
+	    ("rt family is %d, not inet6", dst->sin6_family));
+	*paddr = dst->sin6_addr;
+	dst = (const struct sockaddr_in6 *)rt_mask_const(rt);
+	if (dst == NULL)
+		*plen = 128;
+	else
+		*plen = inet6_get_plen(&dst->sin6_addr);
+}
+
+void
+rt_get_inet6_prefix_pmask(const struct rtentry *rt, struct in6_addr *paddr,
+    struct in6_addr *pmask)
+{
+	const struct sockaddr_in *dst;
+
+	dst = (const struct sockaddr_in *)rt_key_const(rt);
+	KASSERT((dst->sin6_family == AF_INET),
+	    ("rt family is %d, not inet", dst->sin_family));
+	*paddr = dst->sin6_addr;
+	dst = (const struct sockaddr_in6 *)rt_mask_const(rt);
+	if (dst == NULL)
+		memset(pmask, 0xFF, sizeof(struct in6_addr));
+	else
+		*plen = dst->sin6_addr;
+}
+#endif
+
 static void
 rt_set_expire_info(struct rtentry *rt, const struct rt_addrinfo *info)
 {