From fd97136fee495ac0a261dbff642423a45db0ba0c Mon Sep 17 00:00:00 2001
From: Laurent Deru <laurent.deru@cetic.be>
Date: Fri, 8 Nov 2013 15:41:24 +0100
Subject: [PATCH] As RPL Root, drop an incoming DIO from the same instance but
 different DAG

---
 core/net/rpl/rpl-dag.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index 4bc4c1790..9f396202f 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -1173,6 +1173,11 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
     return;
   }
 
+  if(instance->current_dag->rank == ROOT_RANK(instance) && instance->current_dag != dag) {
+    PRINTF("RPL: Root ignored DIO for different DAG\n");
+    return;
+  }
+
   if(dag == NULL) {
     PRINTF("RPL: Adding new DAG to known instance.\n");
     rpl_add_dag(from, dio);