From 34126173b4581b988c22938867be4b3f245bd979 Mon Sep 17 00:00:00 2001
From: Laurent Deru <laurent.deru@cetic.be>
Date: Wed, 30 Sep 2015 09:39:44 +0200
Subject: [PATCH] Add DAG lifetime

---
 core/net/rpl/rpl-conf.h    | 12 ++++++++++++
 core/net/rpl/rpl-dag.c     |  6 ++++++
 core/net/rpl/rpl-private.h |  1 +
 core/net/rpl/rpl-timers.c  |  1 +
 core/net/rpl/rpl.c         | 28 ++++++++++++++++++++++++++++
 core/net/rpl/rpl.h         |  1 +
 6 files changed, 49 insertions(+)

diff --git a/core/net/rpl/rpl-conf.h b/core/net/rpl/rpl-conf.h
index 69199f9ac..f4b2a14fe 100644
--- a/core/net/rpl/rpl-conf.h
+++ b/core/net/rpl/rpl-conf.h
@@ -121,6 +121,18 @@
 #define RPL_DEFAULT_ROUTE_INFINITE_LIFETIME                    0
 #endif /* RPL_CONF_DEFAULT_ROUTE_INFINITE_LIFETIME */
 
+/*
+ * Maximum lifetime of a DAG
+ * When a DODAG is not updated since RPL_CONF_DAG_LIFETIME times the DODAG
+ * maximum DIO interval the DODAG is removed from the list of DODAGS of the
+ * related instance, except if it is the currently joined DODAG.
+ */
+#ifdef RPL_CONF_DAG_LIFETIME
+#define RPL_DAG_LIFETIME                    RPL_CONF_DAG_LIFETIME
+#else
+#define RPL_DAG_LIFETIME                    3
+#endif /* RPL_CONF_DAG_LIFETIME */
+
 /*
  * 
  */
diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index 9d140fbd4..dc6393e6c 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -1334,6 +1334,12 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
     return;
   }
 
+  /* The DIO comes from a valid DAG, we can refresh its lifetime */
+  dag->lifetime = (1UL << (instance->dio_intmin + instance->dio_intdoubl)) / 1000;
+  PRINTF("Set dag ");
+  PRINT6ADDR(&dag->dag_id);
+  PRINTF(" lifetime to %ld\n", dag->lifetime);
+
   /*
    * At this point, we know that this DIO pertains to a DAG that
    * we are already part of. We consider the sender of the DIO to be
diff --git a/core/net/rpl/rpl-private.h b/core/net/rpl/rpl-private.h
index a1adc0d6f..6f4764b27 100644
--- a/core/net/rpl/rpl-private.h
+++ b/core/net/rpl/rpl-private.h
@@ -284,6 +284,7 @@ rpl_dag_t *rpl_alloc_dag(uint8_t, uip_ipaddr_t *);
 rpl_instance_t *rpl_alloc_instance(uint8_t);
 void rpl_free_dag(rpl_dag_t *);
 void rpl_free_instance(rpl_instance_t *);
+void rpl_purge_dags(void);
 
 /* DAG parent management function. */
 rpl_parent_t *rpl_add_parent(rpl_dag_t *, rpl_dio_t *dio, uip_ipaddr_t *);
diff --git a/core/net/rpl/rpl-timers.c b/core/net/rpl/rpl-timers.c
index 27fff0ddf..c0d6c2850 100644
--- a/core/net/rpl/rpl-timers.c
+++ b/core/net/rpl/rpl-timers.c
@@ -66,6 +66,7 @@ static uint8_t dio_send_ok;
 static void
 handle_periodic_timer(void *ptr)
 {
+  rpl_purge_dags();
   rpl_purge_routes();
   rpl_recalculate_ranks();
 
diff --git a/core/net/rpl/rpl.c b/core/net/rpl/rpl.c
index e4724408e..82b11721a 100644
--- a/core/net/rpl/rpl.c
+++ b/core/net/rpl/rpl.c
@@ -300,6 +300,34 @@ rpl_ipv6_neighbor_callback(uip_ds6_nbr_t *nbr)
 }
 /*---------------------------------------------------------------------------*/
 void
+rpl_purge_dags(void)
+{
+  rpl_instance_t *instance;
+  rpl_instance_t *end;
+  int i;
+
+  for(instance = &instance_table[0], end = instance + RPL_MAX_INSTANCES;
+      instance < end; ++instance) {
+    if(instance->used) {
+      for(i = 0; i < RPL_MAX_DAG_PER_INSTANCE; i++) {
+        if(instance->dag_table[i].used) {
+          if(instance->dag_table[i].lifetime == 0) {
+            if(!instance->dag_table[i].joined) {
+              PRINTF("Removing dag ");
+              PRINT6ADDR(&instance->dag_table[i].dag_id);
+              PRINTF("\n");
+              rpl_free_dag(&instance->dag_table[i]);
+            }
+          } else {
+            instance->dag_table[i].lifetime--;
+          }
+        }
+      }
+    }
+  }
+}
+/*---------------------------------------------------------------------------*/
+void
 rpl_init(void)
 {
   uip_ipaddr_t rplmaddr;
diff --git a/core/net/rpl/rpl.h b/core/net/rpl/rpl.h
index 70c877aeb..3b3c99f9f 100644
--- a/core/net/rpl/rpl.h
+++ b/core/net/rpl/rpl.h
@@ -142,6 +142,7 @@ struct rpl_dag {
   rpl_rank_t rank;
   struct rpl_instance *instance;
   rpl_prefix_t prefix_info;
+  uint32_t lifetime;
 };
 typedef struct rpl_dag rpl_dag_t;
 typedef struct rpl_instance rpl_instance_t;