When adding a route fails because there is already a route with the same

(mask,value) in the tree, don't immediately return EEXIST.  Instead, check
to see if the pre-existing route was generated by protcol-cloning.  If so,
then it is OK to simply blow away the old route and re-attempt the insertion.
If not, then fall back to the same error code as before.

1 files changed, 23 insertions, 1 deletions

diff --git a/sys/net/route.c b/sys/net/route.c
index 4f5fdf7..e5bae41 100644
--- a/sys/net/route.c
+++ b/sys/net/route.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)route.c	8.2 (Berkeley) 11/15/93
- *	$Id: route.c,v 1.24 1995/07/10 15:22:37 wollman Exp $
+ *	$Id: route.c,v 1.25 1995/07/29 11:41:02 bde Exp $
  */
 
 #include <sys/param.h>
@@ -465,6 +465,28 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
 		rn = rnh->rnh_addaddr((caddr_t)ndst, (caddr_t)netmask,
 					rnh, rt->rt_nodes);
 		if (rn == 0) {
+			struct rtentry *rt2;
+			/*
+			 * Uh-oh, we already have one of these in the tree.
+			 * We do a special hack: if the route that's already
+			 * there was generated by the protocol-cloning
+			 * mechanism, then we just blow it away and retry
+			 * the insertion of the new one.
+			 */
+			rt2 = rtalloc1(dst, 0, RTF_PRCLONING);
+			if (rt2 && rt2->rt_parent) {
+				rtrequest(RTM_DELETE, 
+					  (struct sockaddr *)rt_key(rt2),
+					  rt2->rt_gateway,
+					  rt_mask(rt2), rt2->rt_flags, 0);
+				RTFREE(rt2);
+				rn = rnh->rnh_addaddr((caddr_t)ndst,
+						      (caddr_t)netmask,
+						      rnh, rt->rt_nodes);
+			}
+		}
+
+		if (rn == 0) {
 			if (rt->rt_gwroute)
 				rtfree(rt->rt_gwroute);
 			if (rt->rt_ifa) {