Add three new route flags to help determine what sort of address

the destination represents.  For IP:

- Iff it is a host route, RTF_LOCAL and RTF_BROADCAST indicate local
  (belongs to this host) and broadcast addresses, respectively.

- For all routes, RTF_MULTICAST is set if the destination is multicast.

The RTF_BROADCAST flag is used by ip_output() to eliminate a call to
in_broadcast() in a common case; this gives about 1% in our packet-generation
experiments.  All three flags might be used (although they aren't now)
to determine whether a packet can be forwarded; a given host route can
represent a forwardable address if:

	(rt->rt_flags & (RTF_HOST | RTF_LOCAL | RTF_BROADCAST | RTF_MULTICAST))
	== RTF_HOST

Obviously, one still has to do all the work if a host route is not present,
but this code allows one to cache the results of such a lookup if rtalloc1()
is called without masking RTF_PRCLONING.

3 files changed, 48 insertions, 11 deletions

diff --git a/sys/net/route.h b/sys/net/route.h
index e6e504a..fa1a1bb 100644
--- a/sys/net/route.h
+++ b/sys/net/route.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)route.h	8.3 (Berkeley) 4/19/94
- * $Id: route.h,v 1.19 1995/12/14 09:53:28 phk Exp $
+ * $Id: route.h,v 1.20 1996/01/30 22:58:00 mpp Exp $
  */
 
 #ifndef _NET_ROUTE_H_
@@ -154,7 +154,10 @@ struct ortentry {
 #define RTF_PROTO3	0x40000		/* protocol specific routing flag */
 #define RTF_CHAINDELETE	0x80000		/* chain is being deleted (internal) */
 #define RTF_PINNED	0x100000	/* future use */
-					/* 0x200000 and up unassigned */
+#define	RTF_LOCAL	0x200000 	/* route represents a local address */
+#define	RTF_BROADCAST	0x400000	/* route represents a bcast address */
+#define	RTF_MULTICAST	0x800000	/* route represents a mcast address */
+					/* 0x1000000 and up unassigned */
 
 /*
  * Routing statistics.
diff --git a/sys/netinet/in_rmx.c b/sys/netinet/in_rmx.c
index df4fc3b..2d671e5 100644
--- a/sys/netinet/in_rmx.c
+++ b/sys/netinet/in_rmx.c
@@ -26,7 +26,7 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: in_rmx.c,v 1.23 1996/01/23 05:15:30 fenner Exp $
+ * $Id: in_rmx.c,v 1.24 1996/04/26 18:31:41 wollman Exp $
  */
 
 /*
@@ -84,9 +84,38 @@ in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
 	/*
 	 * For IP, all unicast non-host routes are automatically cloning.
 	 */
-	if(!(rt->rt_flags & (RTF_HOST | RTF_CLONING))) {
-		if(!IN_MULTICAST(ntohl(sin->sin_addr.s_addr))) {
-			rt->rt_flags |= RTF_PRCLONING;
+	if(IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
+		rt->rt_flags |= RTF_MULTICAST;
+
+	if(!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) {
+		rt->rt_flags |= RTF_PRCLONING;
+	}
+
+	/*
+	 * A little bit of help for both IP output and input:
+	 *   For host routes, we make sure that RTF_BROADCAST
+	 *   is set for anything that looks like a broadcast address.
+	 *   This way, we can avoid an expensive call to in_broadcast()
+	 *   in ip_output() most of the time (because the route passed
+	 *   to ip_output() is almost always a host route).
+	 *
+	 *   We also do the same for local addresses, with the thought
+	 *   that this might one day be used to speed up ip_input().
+	 *
+	 * We also mark routes to multicast addresses as such, because
+	 * it's easy to do and might be useful (but this is much more
+	 * dubious since it's so easy to inspect the address).  (This
+	 * is done above.)
+	 */
+	if (rt->rt_flags & RTF_HOST) {
+		if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
+			rt->rt_flags |= RTF_BROADCAST;
+		} else {
+#define satosin(sa) ((struct sockaddr_in *)sa)
+			if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr
+			    == sin->sin_addr.s_addr)
+				rt->rt_flags |= RTF_LOCAL;
+#undef satosin
 		}
 	}
 
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 5e82035..d937c28 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
- *	$Id: ip_output.c,v 1.35 1996/04/18 15:49:06 wollman Exp $
+ *	$Id: ip_output.c,v 1.36 1996/04/21 13:47:43 bde Exp $
  */
 
 #define _IP_VHL
@@ -94,6 +94,7 @@ ip_output(m0, opt, ro, flags, imo)
 	int len, off, error = 0;
 	struct sockaddr_in *dst;
 	struct in_ifaddr *ia;
+	int isbroadcast;
 
 #ifdef	DIAGNOSTIC
 	if ((m->m_flags & M_PKTHDR) == 0)
@@ -150,6 +151,7 @@ ip_output(m0, opt, ro, flags, imo)
 		}
 		ifp = ia->ia_ifp;
 		ip->ip_ttl = 1;
+		isbroadcast = in_broadcast(dst->sin_addr, ifp);
 	} else {
 		/*
 		 * If this is the case, we probably don't want to allocate
@@ -172,6 +174,10 @@ ip_output(m0, opt, ro, flags, imo)
 		ro->ro_rt->rt_use++;
 		if (ro->ro_rt->rt_flags & RTF_GATEWAY)
 			dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
+		if (ro->ro_rt->rt_flags & RTF_HOST)
+			isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
+		else
+			isbroadcast = in_broadcast(dst->sin_addr, ifp);
 	}
 	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
 		struct in_multi *inm;
@@ -296,7 +302,7 @@ ip_output(m0, opt, ro, flags, imo)
 	 * and verify user is allowed to send
 	 * such a packet.
 	 */
-	if (in_broadcast(dst->sin_addr, ifp)) {
+	if (isbroadcast) {
 		if ((ifp->if_flags & IFF_BROADCAST) == 0) {
 			error = EADDRNOTAVAIL;
 			goto bad;
@@ -311,8 +317,9 @@ ip_output(m0, opt, ro, flags, imo)
 			goto bad;
 		}
 		m->m_flags |= M_BCAST;
-	} else
+	} else {
 		m->m_flags &= ~M_BCAST;
+	}
 
 sendit:
 	/*
@@ -345,7 +352,6 @@ sendit:
 	 */
 	if (ip->ip_off & IP_DF) {
 		error = EMSGSIZE;
-#if 1
 		/*
 		 * This case can happen if the user changed the MTU
 		 * of an interface after enabling IP on it.  Because
@@ -358,7 +364,6 @@ sendit:
 		    && (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
 			ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
 		}
-#endif
 		ipstat.ips_cantfrag++;
 		goto bad;
 	}