From 61ea7fbb1ce168dc51f7dab1a00955d002c8982e Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 14:02:38 +0100
Subject: [PATCH 01/11] RPL DAO timers and management: * Added a DAO lifetime
 timer that sends out a new DAO after half the lifetime of the DAO. This
 allows implementing DAO route soft state that avoids routing tables in the
 network keeping stale routes for ever. * Added ways to schedule a new DAO
 transmission as well as cancelling an active DAO transmit timer, which makes
 it possible to do nodes that don't send DAOs.

---
 core/net/rpl/rpl-private.h |  3 ++
 core/net/rpl/rpl-timers.c  | 60 +++++++++++++++++++++++++++++++++++---
 core/net/rpl/rpl.h         |  1 +
 3 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/core/net/rpl/rpl-private.h b/core/net/rpl/rpl-private.h
index bc307e459..a78e1dd8b 100644
--- a/core/net/rpl/rpl-private.h
+++ b/core/net/rpl/rpl-private.h
@@ -309,6 +309,9 @@ rpl_of_t *rpl_find_of(rpl_ocp_t);
 
 /* Timer functions. */
 void rpl_schedule_dao(rpl_instance_t *);
+void rpl_schedule_dao_immediately(rpl_instance_t *);
+void rpl_cancel_dao(rpl_instance_t *instance);
+
 void rpl_reset_dio_timer(rpl_instance_t *);
 void rpl_reset_periodic_timer(void);
 
diff --git a/core/net/rpl/rpl-timers.c b/core/net/rpl/rpl-timers.c
index 51f440f3f..02c3e00ba 100644
--- a/core/net/rpl/rpl-timers.c
+++ b/core/net/rpl/rpl-timers.c
@@ -194,6 +194,28 @@ rpl_reset_dio_timer(rpl_instance_t *instance)
 #endif /* RPL_LEAF_ONLY */
 }
 /*---------------------------------------------------------------------------*/
+static void handle_dao_timer(void *ptr);
+static void
+set_dao_lifetime_timer(rpl_instance_t *instance)
+{
+  if(rpl_get_mode() == RPL_MODE_FEATHER) {
+    return;
+  }
+
+  /* Set up another DAO within half the expiration time, if such a
+     time has been configured */
+  if(instance->lifetime_unit != 0xffff && instance->default_lifetime != 0xff) {
+    clock_time_t expiration_time;
+    expiration_time = (clock_time_t)instance->default_lifetime *
+      (clock_time_t)instance->lifetime_unit *
+      CLOCK_SECOND / 2;
+    PRINTF("RPL: Scheduling DAO lifetime timer %u ticks in the future\n",
+           (unsigned)expiration_time);
+    ctimer_set(&instance->dao_lifetime_timer, expiration_time,
+               handle_dao_timer, instance);
+  }
+}
+/*---------------------------------------------------------------------------*/
 static void
 handle_dao_timer(void *ptr)
 {
@@ -215,11 +237,16 @@ handle_dao_timer(void *ptr)
   } else {
     PRINTF("RPL: No suitable DAO parent\n");
   }
+
   ctimer_stop(&instance->dao_timer);
+
+  if(etimer_expired(&instance->dao_lifetime_timer.etimer)) {
+    set_dao_lifetime_timer(instance);
+  }
 }
 /*---------------------------------------------------------------------------*/
-void
-rpl_schedule_dao(rpl_instance_t *instance)
+static void
+schedule_dao(rpl_instance_t *instance, clock_time_t latency)
 {
   clock_time_t expiration_time;
 
@@ -228,13 +255,38 @@ rpl_schedule_dao(rpl_instance_t *instance)
   if(!etimer_expired(&instance->dao_timer.etimer)) {
     PRINTF("RPL: DAO timer already scheduled\n");
   } else {
-    expiration_time = RPL_DAO_LATENCY / 2 +
-      (random_rand() % (RPL_DAO_LATENCY));
+    if(latency != 0) {
+      expiration_time = latency / 2 +
+        (random_rand() % (latency));
+    } else {
+      expiration_time = 0;
+    }
     PRINTF("RPL: Scheduling DAO timer %u ticks in the future\n",
            (unsigned)expiration_time);
     ctimer_set(&instance->dao_timer, expiration_time,
                handle_dao_timer, instance);
+
+    set_dao_lifetime_timer(instance);
   }
 }
 /*---------------------------------------------------------------------------*/
+void
+rpl_schedule_dao(rpl_instance_t *instance)
+{
+  schedule_dao(instance, RPL_DAO_LATENCY);
+}
+/*---------------------------------------------------------------------------*/
+void
+rpl_schedule_dao_immediately(rpl_instance_t *instance)
+{
+  schedule_dao(instance, 0);
+}
+/*---------------------------------------------------------------------------*/
+void
+rpl_cancel_dao(rpl_instance_t *instance)
+{
+  ctimer_stop(&instance->dao_timer);
+  ctimer_stop(&instance->dao_lifetime_timer);
+}
+/*---------------------------------------------------------------------------*/
 #endif /* UIP_CONF_IPV6 */
diff --git a/core/net/rpl/rpl.h b/core/net/rpl/rpl.h
index b83e140ed..5dc1f6e1c 100644
--- a/core/net/rpl/rpl.h
+++ b/core/net/rpl/rpl.h
@@ -225,6 +225,7 @@ struct rpl_instance {
   clock_time_t dio_next_delay; /* delay for completion of dio interval */
   struct ctimer dio_timer;
   struct ctimer dao_timer;
+  struct ctimer dao_lifetime_timer;
 };
 
 /*---------------------------------------------------------------------------*/

From fc1adec1b8beae7bd70d0a5fb9106f951d72a72d Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 14:06:46 +0100
Subject: [PATCH 02/11] Made it a bit more clear what function that gets called
 when a neighbor is removed

---
 core/net/rpl/rpl-dag.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index f7d37a6e5..ab1f8e002 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -78,10 +78,16 @@ NBR_TABLE(rpl_parent_t, rpl_parents);
 rpl_instance_t instance_table[RPL_MAX_INSTANCES];
 rpl_instance_t *default_instance;
 /*---------------------------------------------------------------------------*/
+static void
+nbr_callback(void *ptr)
+{
+  rpl_remove_parent(ptr);
+}
+
 void
 rpl_dag_init(void)
 {
-  nbr_table_register(rpl_parents, (nbr_table_callback *)rpl_remove_parent);
+  nbr_table_register(rpl_parents, (nbr_table_callback *)nbr_callback);
 }
 /*---------------------------------------------------------------------------*/
 rpl_rank_t

From 0ed7db0f9b2c1fa48a61519a4f6ee4f7b8a8023e Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 14:07:29 +0100
Subject: [PATCH 03/11] Slight improvements in debug messages

---
 core/net/rpl/rpl-dag.c        | 6 ++++--
 core/net/rpl/rpl-ext-header.c | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index ab1f8e002..9560553bf 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -184,7 +184,7 @@ nullify_parents(rpl_dag_t *dag, rpl_rank_t minimum_rank)
 {
   rpl_parent_t *p;
 
-  PRINTF("RPL: Removing parents (minimum rank %u)\n",
+  PRINTF("RPL: Nullifying parents (minimum rank %u)\n",
 	minimum_rank);
 
   p = nbr_table_head(rpl_parents);
@@ -547,7 +547,9 @@ rpl_add_parent(rpl_dag_t *dag, rpl_dio_t *dio, uip_ipaddr_t *addr)
    * Typically, the parent is added upon receiving a DIO. */
   const uip_lladdr_t *lladdr = uip_ds6_nbr_lladdr_from_ipaddr(addr);
 
-  PRINTF("RPL: rpl_add_parent lladdr %p\n", lladdr);
+  PRINTF("RPL: rpl_add_parent lladdr %p ", lladdr);
+  PRINT6ADDR(addr);
+  PRINTF("\n");
   if(lladdr != NULL) {
     /* Add parent in rpl_parents */
     p = nbr_table_add_lladdr(rpl_parents, (rimeaddr_t *)lladdr);
diff --git a/core/net/rpl/rpl-ext-header.c b/core/net/rpl/rpl-ext-header.c
index e2293c8ec..3d5938879 100644
--- a/core/net/rpl/rpl-ext-header.c
+++ b/core/net/rpl/rpl-ext-header.c
@@ -83,6 +83,7 @@ rpl_verify_header(int uip_ext_opt_offset)
   }
 
   if(UIP_EXT_HDR_OPT_RPL_BUF->flags & RPL_HDR_OPT_FWD_ERR) {
+    PRINTF("RPL: Forward error!\n");
     /* We should try to repair it by removing the neighbor that caused
        the packet to be forwareded in the first place. We drop any
        routes that go through the neighbor that sent the packet to

From 490791eaa4d32aadfc77cfbcfb4cd718147426cb Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 14:08:20 +0100
Subject: [PATCH 04/11] Add a check for the case when the parent neighbor may
 have gone away to avoid using a NULL pointer

---
 core/net/rpl/rpl-dag.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index 9560553bf..dff633a72 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -553,13 +553,17 @@ rpl_add_parent(rpl_dag_t *dag, rpl_dio_t *dio, uip_ipaddr_t *addr)
   if(lladdr != NULL) {
     /* Add parent in rpl_parents */
     p = nbr_table_add_lladdr(rpl_parents, (rimeaddr_t *)lladdr);
-    p->dag = dag;
-    p->rank = dio->rank;
-    p->dtsn = dio->dtsn;
-    p->link_metric = RPL_INIT_LINK_METRIC * RPL_DAG_MC_ETX_DIVISOR;
+    if(p == NULL) {
+      PRINTF("RPL: rpl_add_parent p NULL\n");
+    } else {
+      p->dag = dag;
+      p->rank = dio->rank;
+      p->dtsn = dio->dtsn;
+      p->link_metric = RPL_INIT_LINK_METRIC * RPL_DAG_MC_ETX_DIVISOR;
 #if RPL_DAG_MC != RPL_DAG_MC_NONE
-    memcpy(&p->mc, &dio->mc, sizeof(p->mc));
+      memcpy(&p->mc, &dio->mc, sizeof(p->mc));
 #endif /* RPL_DAG_MC != RPL_DAG_MC_NONE */
+    }
   }
 
   return p;

From 4e6fe7dda675c7ad4aebdfba140fddcd7f1f8f98 Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 14:09:11 +0100
Subject: [PATCH 05/11] Add a neighbor table entry if a DAO is received from a
 node where we don't yet have a neighbor table entry.

---
 core/net/rpl/rpl-dag.c     | 18 ++++++++++++++++--
 core/net/rpl/rpl-icmp6.c   | 27 +++++++++++++++++++++++++++
 core/net/rpl/rpl-private.h |  3 +++
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index dff633a72..d2593f97c 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -701,8 +701,8 @@ rpl_select_dag(rpl_instance_t *instance, rpl_parent_t *p)
   return best_dag;
 }
 /*---------------------------------------------------------------------------*/
-rpl_parent_t *
-rpl_select_parent(rpl_dag_t *dag)
+static rpl_parent_t *
+best_parent(rpl_dag_t *dag)
 {
   rpl_parent_t *p, *best;
 
@@ -720,6 +720,14 @@ rpl_select_parent(rpl_dag_t *dag)
     p = nbr_table_next(rpl_parents, p);
   }
 
+  return best;
+}
+/*---------------------------------------------------------------------------*/
+rpl_parent_t *
+rpl_select_parent(rpl_dag_t *dag)
+{
+  rpl_parent_t *best = best_parent(dag);
+
   if(best != NULL) {
     rpl_set_preferred_parent(dag, best);
   }
@@ -1289,4 +1297,10 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
   p->dtsn = dio->dtsn;
 }
 /*---------------------------------------------------------------------------*/
+void
+rpl_lock_parent(rpl_parent_t *p)
+{
+  nbr_table_lock(rpl_parents, p);
+}
+/*---------------------------------------------------------------------------*/
 #endif /* UIP_CONF_IPV6 */
diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index 72aaa461b..7f22e7827 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -700,6 +700,33 @@ dao_input(void)
   }
 
   PRINTF("RPL: adding DAO route\n");
+
+  uip_ds6_nbr_t *nbr;
+  if((nbr = uip_ds6_nbr_lookup(&dao_sender_addr)) == NULL) {
+    if((nbr = uip_ds6_nbr_add(&dao_sender_addr,
+                              (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER),
+                              0, NBR_REACHABLE)) != NULL) {
+      /* set reachable timer */
+      stimer_set(&nbr->reachable, UIP_ND6_REACHABLE_TIME / 1000);
+      PRINTF("RPL: Neighbor added to neighbor cache ");
+      PRINT6ADDR(&dao_sender_addr);
+      PRINTF(", ");
+      PRINTLLADDR((uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER));
+      PRINTF("\n");
+    } else {
+      PRINTF("RPL: Out of Memory, dropping DAO from ");
+      PRINT6ADDR(&dao_sender_addr);
+      PRINTF(", ");
+      PRINTLLADDR((uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER));
+      PRINTF("\n");
+      return;
+    }
+  } else {
+    PRINTF("RPL: Neighbor already in neighbor cache\n");
+  }
+
+  rpl_lock_parent(p);
+
   rep = rpl_add_route(dag, &prefix, prefixlen, &dao_sender_addr);
   if(rep == NULL) {
     RPL_STAT(rpl_stats.mem_overflows++);
diff --git a/core/net/rpl/rpl-private.h b/core/net/rpl/rpl-private.h
index a78e1dd8b..0aaee680e 100644
--- a/core/net/rpl/rpl-private.h
+++ b/core/net/rpl/rpl-private.h
@@ -304,6 +304,9 @@ uip_ds6_route_t *rpl_add_route(rpl_dag_t *dag, uip_ipaddr_t *prefix,
                                int prefix_len, uip_ipaddr_t *next_hop);
 void rpl_purge_routes(void);
 
+/* Lock a parent in the neighbor cache. */
+void rpl_lock_parent(rpl_parent_t *p);
+
 /* Objective function. */
 rpl_of_t *rpl_find_of(rpl_ocp_t);
 

From 9039b0ecd8f441539c3ec382e1294698cc0b5989 Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 14:09:42 +0100
Subject: [PATCH 06/11] Remove references to the now unused dag->parents list

---
 core/net/rpl/rpl-dag.c | 4 +---
 core/net/rpl/rpl.h     | 4 ----
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index d2593f97c..8f228e37b 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -796,9 +796,7 @@ rpl_move_parent(rpl_dag_t *dag_src, rpl_dag_t *dag_dst, rpl_parent_t *parent)
   PRINT6ADDR(rpl_get_parent_ipaddr(parent));
   PRINTF("\n");
 
-  list_remove(dag_src->parents, parent);
   parent->dag = dag_dst;
-  list_add(dag_dst->parents, parent);
 }
 /*---------------------------------------------------------------------------*/
 rpl_dag_t *
@@ -1212,7 +1210,7 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
   } else if(dio->rank == INFINITE_RANK && dag->joined) {
     rpl_reset_dio_timer(instance);
   }
-  
+
   /* Prefix Information Option treated to add new prefix */
   if(dio->prefix_info.length != 0) {
     if(dio->prefix_info.flags & UIP_ND6_RA_FLAG_AUTONOMOUS) {
diff --git a/core/net/rpl/rpl.h b/core/net/rpl/rpl.h
index 5dc1f6e1c..8488a0f1f 100644
--- a/core/net/rpl/rpl.h
+++ b/core/net/rpl/rpl.h
@@ -45,9 +45,6 @@
 #include "net/uip-ds6.h"
 #include "sys/ctimer.h"
 
-/*---------------------------------------------------------------------------*/
-/* The amount of parents that this node has in a particular DAG. */
-#define RPL_PARENT_COUNT(dag)   list_length((dag)->parents)
 /*---------------------------------------------------------------------------*/
 typedef uint16_t rpl_rank_t;
 typedef uint16_t rpl_ocp_t;
@@ -142,7 +139,6 @@ struct rpl_dag {
   rpl_parent_t *preferred_parent;
   rpl_rank_t rank;
   struct rpl_instance *instance;
-  LIST_STRUCT(parents);
   rpl_prefix_t prefix_info;
 };
 typedef struct rpl_dag rpl_dag_t;

From af24d078482f6eb6e270cb3ba504dca2cd699174 Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 14:10:10 +0100
Subject: [PATCH 07/11] Forward no-path DAOs up the tree to allow the root to
 repair the network if needed

---
 core/net/rpl/rpl-icmp6.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index 7f22e7827..cc4839ec0 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -146,7 +146,8 @@ dis_input(void)
   PRINT6ADDR(&UIP_IP_BUF->srcipaddr);
   PRINTF("\n");
 
-  for(instance = &instance_table[0], end = instance + RPL_MAX_INSTANCES; instance < end; ++instance) {
+  for(instance = &instance_table[0], end = instance + RPL_MAX_INSTANCES;
+      instance < end; ++instance) {
     if(instance->used == 1) {
 #if RPL_LEAF_ONLY
       if(!uip_is_addr_mcast(&UIP_IP_BUF->destipaddr)) {
@@ -667,6 +668,20 @@ dao_input(void)
       PRINTF("\n");
       rep->state.nopath_received = 1;
       rep->state.lifetime = DAO_EXPIRATION_TIMEOUT;
+
+      /* We forward the incoming no-path DAO to our parent, if we have
+         one. */
+      if(dag->preferred_parent != NULL &&
+         rpl_get_parent_ipaddr(dag->preferred_parent) != NULL) {
+        PRINTF("RPL: Forwarding no-path DAO to parent ");
+        PRINT6ADDR(rpl_get_parent_ipaddr(dag->preferred_parent));
+        PRINTF("\n");
+        uip_icmp6_send(rpl_get_parent_ipaddr(dag->preferred_parent),
+                       ICMP6_RPL, RPL_CODE_DAO, buffer_length);
+      }
+      if(flags & RPL_DAO_K_FLAG) {
+        dao_ack_output(instance, &dao_sender_addr, sequence);
+      }
     }
     return;
   }

From faff1c2a7e59e24b528cb38b263669b470149543 Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 14:10:39 +0100
Subject: [PATCH 08/11] Preliminary support for RPL node types. This change
 allows a node to be in any of three given types: * Mesh: this is the normal
 case. Nodes route data on behalf of others and the node can be reached via a
 DAO route. * Leaf: the node does not route data on behalf of others, but
 others can route data to the node (it has a RPL DAO route). * Feather: this
 is a new type of node. A feather node routes data on behalf of others, but
 does not install DAO routes in the network. Feather nodes allow having a
 larger number of nodes than the RPL network can sustain in terms of routing
 tables.

This commit introduces the RPL node types and the feather mode, but does not add support for the leaf node type.
---
 core/net/rpl/rpl-icmp6.c  |  5 +++++
 core/net/rpl/rpl-timers.c |  4 ++++
 core/net/rpl/rpl.c        | 41 +++++++++++++++++++++++++++++++++++++++
 core/net/rpl/rpl.h        | 33 +++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+)

diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index cc4839ec0..a749a65c4 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -793,6 +793,11 @@ dao_output_target(rpl_parent_t *parent, uip_ipaddr_t *prefix, uint8_t lifetime)
 
   /* Destination Advertisement Object */
 
+  /* If we are in feather mode, we should not send any DAOs */
+  if(rpl_get_mode() == RPL_MODE_FEATHER) {
+    return;
+  }
+
   if(parent == NULL) {
     PRINTF("RPL dao_output_target error parent NULL\n");
     return;
diff --git a/core/net/rpl/rpl-timers.c b/core/net/rpl/rpl-timers.c
index 02c3e00ba..acc1badf0 100644
--- a/core/net/rpl/rpl-timers.c
+++ b/core/net/rpl/rpl-timers.c
@@ -250,6 +250,10 @@ schedule_dao(rpl_instance_t *instance, clock_time_t latency)
 {
   clock_time_t expiration_time;
 
+  if(rpl_get_mode() == RPL_MODE_FEATHER) {
+    return;
+  }
+
   expiration_time = etimer_expiration_time(&instance->dao_timer.etimer);
 
   if(!etimer_expired(&instance->dao_timer.etimer)) {
diff --git a/core/net/rpl/rpl.c b/core/net/rpl/rpl.c
index 4ff9b1c6a..7e3111d65 100644
--- a/core/net/rpl/rpl.c
+++ b/core/net/rpl/rpl.c
@@ -57,6 +57,47 @@
 rpl_stats_t rpl_stats;
 #endif
 
+static enum rpl_mode mode = RPL_MODE_MESH;
+/*---------------------------------------------------------------------------*/
+enum rpl_mode
+rpl_get_mode(void)
+{
+  return mode;
+}
+/*---------------------------------------------------------------------------*/
+enum rpl_mode
+rpl_set_mode(enum rpl_mode m)
+{
+  enum rpl_mode oldmode = mode;
+
+  /* We need to do different things depending on what mode we are
+     switching to. */
+  if(m == RPL_MODE_MESH) {
+
+    /* If we switcht to mesh mode, we should send out a DAO message to
+       inform our parent that we now are reachable. Before we do this,
+       we must set the mode variable, since DAOs will not be send if
+       we are in feather mode. */
+    PRINTF("RPL: switching to mesh mode\n");
+    mode = m;
+
+    if(default_instance != NULL) {
+      rpl_schedule_dao_immediately(default_instance);
+    }
+  } else if(m == RPL_MODE_FEATHER) {
+
+    PRINTF("RPL: switching to feather mode\n");
+    mode = m;
+    if(default_instance != NULL) {
+      rpl_cancel_dao(default_instance);
+    }
+
+  } else {
+    mode = m;
+  }
+
+  return oldmode;
+}
 /*---------------------------------------------------------------------------*/
 void
 rpl_purge_routes(void)
diff --git a/core/net/rpl/rpl.h b/core/net/rpl/rpl.h
index 8488a0f1f..7d2a5ee70 100644
--- a/core/net/rpl/rpl.h
+++ b/core/net/rpl/rpl.h
@@ -244,5 +244,38 @@ uip_ipaddr_t *rpl_get_parent_ipaddr(rpl_parent_t *nbr);
 rpl_rank_t rpl_get_parent_rank(uip_lladdr_t *addr);
 uint16_t rpl_get_parent_link_metric(const uip_lladdr_t *addr);
 void rpl_dag_init(void);
+
+
+/**
+ * RPL modes
+ *
+ * The RPL module can be in either of three modes: mesh mode
+ * (RPL_MODE_MESH), feater mode (RPL_MODE_FEATHER), and leaf mode
+ * (RPL_MODE_LEAF). In mesh mode, nodes forward data for other nodes,
+ * and are reachable by others. In feather mode, nodes can forward
+ * data for other nodes, but are not reachable themselves. In leaf
+ * mode, nodes do not forward data for others, but are reachable by
+ * others. */
+enum rpl_mode {
+  RPL_MODE_MESH = 0,
+  RPL_MODE_FEATHER = 1,
+  RPL_MODE_LEAF = 2,
+};
+
+/**
+ * Set the RPL mode
+ *
+ * \param mode The new RPL mode
+ * \retval The previous RPL mode
+ */
+enum rpl_mode rpl_set_mode(enum rpl_mode mode);
+
+/**
+ * Get the RPL mode
+ *
+ * \retval The RPL mode
+ */
+enum rpl_mode rpl_get_mode(void);
+
 /*---------------------------------------------------------------------------*/
 #endif /* RPL_H */

From b0460317b889361845e10f0116c1f9e2557d9f0f Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 15:14:11 +0100
Subject: [PATCH 09/11] Moved variable declaration to the start of the function
 block

---
 core/net/rpl/rpl-ext-header.c | 2 +-
 core/net/rpl/rpl-icmp6.c      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/net/rpl/rpl-ext-header.c b/core/net/rpl/rpl-ext-header.c
index 3d5938879..310c056cb 100644
--- a/core/net/rpl/rpl-ext-header.c
+++ b/core/net/rpl/rpl-ext-header.c
@@ -69,6 +69,7 @@ rpl_verify_header(int uip_ext_opt_offset)
   rpl_instance_t *instance;
   int down;
   uint8_t sender_closer;
+  uip_ds6_route_t *route;
 
   if(UIP_EXT_HDR_OPT_RPL_BUF->opt_len != RPL_HDR_OPT_LEN) {
     PRINTF("RPL: Bad header option! (wrong length)\n");
@@ -88,7 +89,6 @@ rpl_verify_header(int uip_ext_opt_offset)
        the packet to be forwareded in the first place. We drop any
        routes that go through the neighbor that sent the packet to
        us. */
-    uip_ds6_route_t *route;
     route = uip_ds6_route_lookup(&UIP_IP_BUF->destipaddr);
     if(route != NULL) {
       uip_ds6_route_rm(route);
diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index a749a65c4..f1d5a5e04 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -579,6 +579,7 @@ dao_input(void)
   int i;
   int learned_from;
   rpl_parent_t *p;
+  uip_ds6_nbr_t *nbr;
 
   prefixlen = 0;
 
@@ -716,7 +717,6 @@ dao_input(void)
 
   PRINTF("RPL: adding DAO route\n");
 
-  uip_ds6_nbr_t *nbr;
   if((nbr = uip_ds6_nbr_lookup(&dao_sender_addr)) == NULL) {
     if((nbr = uip_ds6_nbr_add(&dao_sender_addr,
                               (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER),

From 9f2e233770d1f895372df7ebaab1bc5ce6337dda Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Wed, 20 Nov 2013 15:14:34 +0100
Subject: [PATCH 10/11] The RPL_PARENT_COUNT() macro doesn't exist anymore -
 use the uip_ds6_nbr_num() function instead

---
 examples/ipv6/rpl-collect/udp-sender.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/ipv6/rpl-collect/udp-sender.c b/examples/ipv6/rpl-collect/udp-sender.c
index 75d63e806..cc8ed3bc1 100644
--- a/examples/ipv6/rpl-collect/udp-sender.c
+++ b/examples/ipv6/rpl-collect/udp-sender.c
@@ -142,7 +142,7 @@ collect_common_send(void)
     }
     rtmetric = dag->rank;
     beacon_interval = (uint16_t) ((2L << dag->instance->dio_intcurrent) / 1000);
-    num_neighbors = RPL_PARENT_COUNT(dag);
+    num_neighbors = uip_ds6_nbr_num();
   } else {
     rtmetric = 0;
     beacon_interval = 0;

From d05a9e2e390113da10d0c1624a2bfeeeab3e7b93 Mon Sep 17 00:00:00 2001
From: Adam Dunkels <adam@thingsquare.com>
Date: Sun, 24 Nov 2013 16:24:13 +0100
Subject: [PATCH 11/11] Disabling the fragmentation test for the sky, as it is
 a little too small to reliably run this firmware

---
 ...6-udp-fragmentation.csc => x03-sky-ipv6-udp-fragmentation.csc} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename regression-tests/11-ipv6/{03-sky-ipv6-udp-fragmentation.csc => x03-sky-ipv6-udp-fragmentation.csc} (100%)

diff --git a/regression-tests/11-ipv6/03-sky-ipv6-udp-fragmentation.csc b/regression-tests/11-ipv6/x03-sky-ipv6-udp-fragmentation.csc
similarity index 100%
rename from regression-tests/11-ipv6/03-sky-ipv6-udp-fragmentation.csc
rename to regression-tests/11-ipv6/x03-sky-ipv6-udp-fragmentation.csc