From b557000c20d3e0729c5083f04efd106a221c0a41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cenk=20G=C3=BCndo=C4=9Fan?= <cnkgndgn@gmail.com>
Date: Tue, 17 Mar 2015 13:38:38 +0100
Subject: [PATCH] rpl: remove global variable indicating the root node

---
 sys/net/routing/rpl/rpl_control_messages.c | 33 ++++++++++++----------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/sys/net/routing/rpl/rpl_control_messages.c b/sys/net/routing/rpl/rpl_control_messages.c
index 8d08e1524e..65588eaab8 100644
--- a/sys/net/routing/rpl/rpl_control_messages.c
+++ b/sys/net/routing/rpl/rpl_control_messages.c
@@ -35,9 +35,6 @@ static char addr_str[IPV6_MAX_ADDR_STR_LEN];
 #endif
 #include "debug.h"
 
-/* Identification variables */
-static char i_am_root;
-
 /* in send buffer we need space for LL_HDR */
 static uint8_t rpl_send_buffer[BUFFER_SIZE];
 
@@ -244,7 +241,6 @@ void rpl_init_root(rpl_options_t *rpl_opts)
         return;
     }
 
-    i_am_root = 1;
     trickle_start(rpl_process_pid, &dodag->trickle, RPL_MSG_TYPE_TRICKLE_INTERVAL,
                   RPL_MSG_TYPE_TRICKLE_CALLBACK, (1 << dodag->dio_min), dodag->dio_interval_doubling,
                   dodag->dio_redundancy);
@@ -252,9 +248,19 @@ void rpl_init_root(rpl_options_t *rpl_opts)
 
 }
 
+/* TODO: this function is used by the ip layer for source routing (non-storing mode)
+ * to determine if the node is root and change the dodag direction (upwards -> downwards).
+ * This is a hack and needs to be refactored when the new network stack is ready.
+ */
 uint8_t rpl_is_root(void)
 {
-    return i_am_root;
+    rpl_dodag_t *dodag, *end;
+    for (dodag = rpl_dodags, end = dodag + RPL_MAX_DODAGS; dodag < end; dodag++) {
+        if (dodag->node_status == ROOT_NODE) {
+            return 1;
+        }
+    }
+    return 0;
 }
 
 void rpl_send_DIO(rpl_dodag_t *mydodag, ipv6_addr_t *destination)
@@ -345,12 +351,12 @@ void rpl_send_DAO(rpl_dodag_t *my_dodag, ipv6_addr_t *destination, uint8_t lifet
 
 #endif
 
-    if (i_am_root) {
+    if (my_dodag == NULL) {
+        DEBUGF("send_DAO: I have no my_dodag\n");
         return;
     }
 
-    if (my_dodag == NULL) {
-        DEBUGF("send_DAO: I have no my_dodag\n");
+    if (my_dodag->node_status == ROOT_NODE) {
         return;
     }
 
@@ -754,13 +760,9 @@ void rpl_recv_DIO(void)
 void rpl_recv_DAO(void)
 {
 #if RPL_DEFAULT_MOP == RPL_MOP_NON_STORING_MODE
-
-    if (!i_am_root) {
-        DEBUGF("[Error] something went wrong - got a DAO.\n");
-        return;
-    }
-
-#endif
+    DEBUGF("[Error] something went wrong - got a DAO.\n");
+    return;
+#else
     ipv6_buf = get_rpl_ipv6_buf();
     rpl_dao_buf = get_rpl_dao_buf();
     DEBUG("instance %04X ", rpl_dao_buf->rpl_instanceid);
@@ -854,6 +856,7 @@ void rpl_recv_DAO(void)
         RPL_COUNTER_INCREMENT(my_dodag->dao_seq);
         rpl_delay_dao(my_dodag);
     }
+#endif
 }
 
 void rpl_recv_DIS(void)