Invalidate cached forwarding route (ipforward_rt) whenever a new route

is added to the routing table, otherwise we may end up using the wrong
route when forwarding.

PR:		kern/10778
Reviewed by:	silence on -net

1 files changed, 12 insertions, 0 deletions

diff --git a/sys/netinet/in_rmx.c b/sys/netinet/in_rmx.c
index 51a5846..16ea5be 100644
--- a/sys/netinet/in_rmx.c
+++ b/sys/netinet/in_rmx.c
@@ -54,6 +54,7 @@
 #include <net/route.h>
 #include <netinet/in.h>
 #include <netinet/in_var.h>
+#include <netinet/ip_var.h>
 
 extern int	in_inithead __P((void **head, int off));
 
@@ -137,6 +138,17 @@ in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
 			RTFREE(rt2);
 		}
 	}
+
+	/*
+	 * If the new route created successfully, and we are forwarding,
+	 * and there is a cached route, free it.  Otherwise, we may end
+	 * up using the wrong route.
+	 */
+	if (ret != NULL && ipforwarding && ipforward_rt.ro_rt) {
+		RTFREE(ipforward_rt.ro_rt);
+		ipforward_rt.ro_rt = 0;
+	}
+
 	return ret;
 }