From 39255ee8f81641a769358b8a0ce426137eaa2ea1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cenk=20G=C3=BCndo=C4=9Fan?= <cnkgndgn@gmail.com>
Date: Tue, 15 Mar 2016 16:34:06 +0100
Subject: [PATCH] gnrc_rpl: make DODAG_CONF optional when joining DODAG

---
 sys/include/net/gnrc/rpl.h                           | 12 +++++++++++-
 sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c |  5 +++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/sys/include/net/gnrc/rpl.h b/sys/include/net/gnrc/rpl.h
index b1c1055cee..d2aa5ba435 100644
--- a/sys/include/net/gnrc/rpl.h
+++ b/sys/include/net/gnrc/rpl.h
@@ -27,7 +27,7 @@
  * CFLAGS
  * ------
  *
- *  - Exclude Prefix Information Options from DIOs
+ * - Exclude Prefix Information Options from DIOs
  *   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.mk}
  *   CFLAGS += -DGNRC_RPL_WITHOUT_PIO
  *   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -39,6 +39,16 @@
  *   CFLAGS += -DGNRC_RPL_DEFAULT_DIO_REDUNDANCY_CONSTANT=10
  *   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
+ * - Make reception of DODAG_CONF optional when joining a DODAG.
+ *   This will use the default trickle parameters until a
+ *   DODAG_CONF is received from the parent. The DODAG_CONF is
+ *   requested once from the parent while joining the DODAG.
+ *   The standard behaviour is to request a DODAG_CONF and join
+ *   only a DODAG once a DODAG_CONF is received.
+ *   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.mk}
+ *   CFLAGS += -DGNRC_RPL_DODAG_CONF_OPTIONAL_ON_JOIN
+ *   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
  * @{
  *
  * @file
diff --git a/sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c b/sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c
index 7563f7189f..e429f60fd5 100644
--- a/sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c
+++ b/sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c
@@ -567,10 +567,15 @@ void gnrc_rpl_recv_DIO(gnrc_rpl_dio_t *dio, ipv6_addr_t *src, uint16_t len)
         }
 
         if (!(included_opts & (((uint32_t) 1) << GNRC_RPL_OPT_DODAG_CONF))) {
+#ifndef GNRC_RPL_DODAG_CONF_OPTIONAL_ON_JOIN
             DEBUG("RPL: DIO without DODAG_CONF option - remove DODAG and request new DIO\n");
             gnrc_rpl_instance_remove(inst);
             gnrc_rpl_send_DIS(NULL, src);
             return;
+#else
+            DEBUG("RPL: DIO without DODAG_CONF option - use default trickle parameters\n");
+            gnrc_rpl_send_DIS(NULL, src);
+#endif
         }
 
         gnrc_rpl_delay_dao(dodag);