Minor rpl-lite fixes for DAG leaving/joining

apps/shell/shell-commands.c

@@ -220,7 +220,7 @@ PT_THREAD(cmd_rpl_set_root(struct pt *pt, shell_output_func output, char *args))
   } else {
     if(rpl_dag_root_is_root()) {
       SHELL_OUTPUT(output, "Setting as non-root node: leaving DAG\n");
-      rpl_dag_leave();
+      rpl_dag_poison_and_leave();
     } else {
       SHELL_OUTPUT(output, "Node is not a DAG root\n");
     }

core/net/rpl-lite/rpl-dag.c

@@ -88,8 +88,10 @@ rpl_dag_leave(void)
   LOG_INFO_(", instance %u\n", curr_instance.instance_id);
 
   /* Issue a no-path DAO */
+  if(!rpl_dag_root_is_root()) {
     RPL_LOLLIPOP_INCREMENT(curr_instance.dag.dao_curr_seqno);
     rpl_icmp6_dao_output(0);
+  }
 
   /* Forget past link statistics */
   link_stats_reset();
@@ -111,6 +113,13 @@ rpl_dag_leave(void)
 }
 /*---------------------------------------------------------------------------*/
 void
+rpl_dag_poison_and_leave(void)
+{
+  curr_instance.dag.state = DAG_POISONING;
+  rpl_timers_schedule_state_update();
+}
+/*---------------------------------------------------------------------------*/
+void
 rpl_dag_periodic(unsigned seconds)
 {
   if(curr_instance.used) {
@@ -223,11 +232,13 @@ rpl_dag_ready_to_advertise(void)
 void
 rpl_dag_update_state(void)
 {
-  if(curr_instance.used) {
+  rpl_rank_t old_rank;
-    if(!rpl_dag_root_is_root()) {
-      rpl_nbr_t *old_parent = curr_instance.dag.preferred_parent;
-      rpl_rank_t old_rank = curr_instance.dag.rank;
 
+  if(!curr_instance.used) {
+    return;
+  }
+
+  old_rank = curr_instance.dag.rank;
   /* Any scheduled state update is no longer needed */
   rpl_timers_unschedule_state_update();
 
@@ -240,7 +251,8 @@ rpl_dag_update_state(void)
       rpl_timers_dio_reset("Poison routes");
       rpl_timers_schedule_leaving();
     }
-      } else {
+  } else if(!rpl_dag_root_is_root()) {
+    rpl_nbr_t *old_parent = curr_instance.dag.preferred_parent;
     rpl_nbr_t *nbr;
 
     /* Select and set preferred parent */
@@ -304,16 +316,14 @@ rpl_dag_update_state(void)
         rpl_timers_schedule_leaving();
       }
 
-  #if LOG_INFO_ENABLED
+#if LOG_INFO_ENABLED
       rpl_neighbor_print_list("Parent switch");
-  #endif /* LOG_INFO_ENABLED */
+#endif /* LOG_INFO_ENABLED */
-        }
     }
   }
 
   /* Finally, update metric container */
   curr_instance.of->update_metric_container();
-  }
 }
 /*---------------------------------------------------------------------------*/
 static rpl_nbr_t *

core/net/rpl-lite/rpl-dag.h

@@ -57,6 +57,11 @@
  * \return The description string
 */
 const char *rpl_dag_state_to_str(enum rpl_dag_state state);
+/**
+ * Start poisoning and leave the DAG after a delay
+ *
+*/
+void rpl_dag_poison_and_leave(void);
 /**
  * Leaves the current DAG
  *

core/net/rpl-lite/rpl-icmp6.c

@@ -557,10 +557,19 @@ rpl_icmp6_dao_output(uint8_t lifetime)
   /* Make sure we're up-to-date before sending data out */
   rpl_dag_update_state();
 
-  if(!curr_instance.used || curr_instance.dag.preferred_parent == NULL
+  if(!curr_instance.used) {
-    || prefix == NULL || parent_ipaddr == NULL || curr_instance.mop == RPL_MOP_NO_DOWNWARD_ROUTES) {
+    LOG_WARN("rpl_icmp6_dao_output: not in an instance, skip sending DAO\n");
-    LOG_WARN("rpl_icmp6_dao_output: node not ready to send a DAO (used %u, pref parent %u, prefix %u, mop %u)\n",
+    return;
-        curr_instance.used, curr_instance.dag.preferred_parent != NULL && parent_ipaddr != NULL, prefix != NULL, curr_instance.mop);
+  }
+
+  if(curr_instance.dag.preferred_parent == NULL) {
+    LOG_WARN("rpl_icmp6_dao_output: no preferred parent, skip sending DAO\n");
+    return;
+  }
+
+  if(prefix == NULL || parent_ipaddr == NULL || curr_instance.mop == RPL_MOP_NO_DOWNWARD_ROUTES) {
+    LOG_WARN("rpl_icmp6_dao_output: node not ready to send a DAO (prefix %p, parent addr %p, mop %u)\n",
+                    prefix, parent_ipaddr, curr_instance.mop);
     return;
   }