Make DODAG ID selection RFC 6550-compliant

Some calls to `rpl_set_root` select a hardcoded DODAG ID
(0x1111, 0x1100, 0, 0, 0, 0, 0, 0x0011)

This is against what RFC 6550 says. We change these calls
to select a DODAG ID corresponding to a routable v6 address
corresponding to the root

examples/ipv6/native-border-router/border-router.c

@@ -61,8 +61,6 @@
 
 #define MAX_SENSORS 4
 
-uint16_t dag_id[] = {0x1111, 0x1100, 0, 0, 0, 0, 0, 0x0011};
-
 extern long slip_sent;
 extern long slip_received;
 
@@ -290,19 +288,25 @@ border_router_set_sensors(const char *data, int len)
 static void
 set_prefix_64(const uip_ipaddr_t *prefix_64)
 {
+  rpl_dag_t *dag;
   uip_ipaddr_t ipaddr;
   memcpy(&prefix, prefix_64, 16);
   memcpy(&ipaddr, prefix_64, 16);
 
   prefix_set = 1;
   uip_ds6_set_addr_iid(&ipaddr, &uip_lladdr);
   uip_ds6_addr_add(&ipaddr, 0, ADDR_AUTOCONF);
+
+  dag = rpl_set_root(RPL_DEFAULT_INSTANCE, &ipaddr);
+  if(dag != NULL) {
+    rpl_set_prefix(dag, &prefix, 64);
+    PRINTF("created a new RPL dag\n");
+  }
 }
 /*---------------------------------------------------------------------------*/
 PROCESS_THREAD(border_router_process, ev, data)
 {
   static struct etimer et;
-  rpl_dag_t *dag;
 
   PROCESS_BEGIN();
   prefix_set = 0;
@@ -336,12 +340,6 @@ PROCESS_THREAD(border_router_process, ev, data)
     }
   }
 
-  dag = rpl_set_root(RPL_DEFAULT_INSTANCE,(uip_ip6addr_t *)dag_id);
-  if(dag != NULL) {
-    rpl_set_prefix(dag, &prefix, 64);
-    PRINTF("created a new RPL dag\n");
-  }
-
 #if DEBUG
   print_local_addresses();
 #endif

examples/ipv6/rpl-border-router/border-router.c

@@ -54,8 +54,6 @@
 #define DEBUG DEBUG_NONE
 #include "net/ip/uip-debug.h"
 
-uint16_t dag_id[] = {0x1111, 0x1100, 0, 0, 0, 0, 0, 0x0011};
-
 static uip_ipaddr_t prefix;
 static uint8_t prefix_set;
 
@@ -320,18 +318,24 @@ request_prefix(void)
 void
 set_prefix_64(uip_ipaddr_t *prefix_64)
 {
+  rpl_dag_t *dag;
   uip_ipaddr_t ipaddr;
   memcpy(&prefix, prefix_64, 16);
   memcpy(&ipaddr, prefix_64, 16);
   prefix_set = 1;
   uip_ds6_set_addr_iid(&ipaddr, &uip_lladdr);
   uip_ds6_addr_add(&ipaddr, 0, ADDR_AUTOCONF);
+
+  dag = rpl_set_root(RPL_DEFAULT_INSTANCE, &ipaddr);
+  if(dag != NULL) {
+    rpl_set_prefix(dag, &prefix, 64);
+    PRINTF("created a new RPL dag\n");
+  }
 }
 /*---------------------------------------------------------------------------*/
 PROCESS_THREAD(border_router_process, ev, data)
 {
   static struct etimer et;
-  rpl_dag_t *dag;
 
   PROCESS_BEGIN();
 
@@ -363,12 +367,6 @@ PROCESS_THREAD(border_router_process, ev, data)
     PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));
   }
 
-  dag = rpl_set_root(RPL_DEFAULT_INSTANCE,(uip_ip6addr_t *)dag_id);
-  if(dag != NULL) {
-    rpl_set_prefix(dag, &prefix, 64);
-    PRINTF("created a new RPL dag\n");
-  }
-
   /* Now turn the radio on, but disable radio duty cycling.
    * Since we are the DAG root, reception delays would constrain mesh throughbut.
    */