reset Dodag if global address is lost.

If we lose the dodag_id address we need to restart Border router

Author: Mika Tervonen

source/6LoWPAN/ws/ws_bbr_api.c

@@ -41,6 +41,9 @@
 
 #ifdef HAVE_WS
 
+static uint8_t static_dodag_prefix[8] = {0xfd,0x00,0x61, 0x72, 0x6d};
+static uint8_t static_dodag_id[16] = {0};
+
 static void ws_bbr_rpl_root_activate(uint8_t *dodag_prefix, uint8_t *dodag_id)
 {
     tr_debug("RPL root Activate");
@@ -61,10 +64,18 @@ static void ws_bbr_rpl_root_activate(uint8_t *dodag_prefix, uint8_t *dodag_id)
     };
 
     rpl_data_init_root();
+
+    if (protocol_6lowpan_rpl_root_dodag) {
+        rpl_control_delete_dodag_root(protocol_6lowpan_rpl_domain, protocol_6lowpan_rpl_root_dodag);
+        protocol_6lowpan_rpl_root_dodag = NULL;
+    }
+
     protocol_6lowpan_rpl_root_dodag = rpl_control_create_dodag_root(protocol_6lowpan_rpl_domain, RPL_INSTANCE_ID, dodag_id, &new_conf, new_conf.min_hop_rank_increase, RPL_GROUNDED | RPL_MODE_NON_STORING | RPL_DODAG_PREF(0));
     if (!protocol_6lowpan_rpl_root_dodag) {
         tr_err("RPL dodag init failed");
+        return;
     }
+    memcpy(static_dodag_id,dodag_id,16);
 
     // RPL memory limits set larger for Border router
     rpl_control_set_memory_limits(64*1024, 0);
@@ -76,8 +87,6 @@ static void ws_bbr_rpl_root_activate(uint8_t *dodag_prefix, uint8_t *dodag_id)
     rpl_control_update_dodag_route(protocol_6lowpan_rpl_root_dodag, NULL, 0, 0, 0xffffffff, false);
 }
 
-static uint8_t static_dodag_prefix[8] = {0xfd,0x00,0x61, 0x72, 0x6d};
-
 static void ws_bbr_root_start(protocol_interface_info_entry_t *cur)
 {
     uint8_t *bbr_prefix_ptr = NULL;
@@ -119,6 +128,15 @@ void ws_bbr_seconds_timer(protocol_interface_info_entry_t *cur, uint32_t seconds
        return;
    }
 
+   if (protocol_6lowpan_rpl_root_dodag){
+       // Border router is active
+       if (0 != protocol_interface_address_compare(static_dodag_id)) {
+           // Dodag has become invalid need to delete
+           tr_info("RPL dodag not valid anymore");
+           rpl_control_delete_dodag_root(protocol_6lowpan_rpl_domain, protocol_6lowpan_rpl_root_dodag);
+           protocol_6lowpan_rpl_root_dodag = NULL;
+       }
+   }
    if (!protocol_6lowpan_rpl_root_dodag) {
        // RPL configured
        // 1. Wait for backend connection

source/RPL/rpl_control.c

@@ -455,7 +455,7 @@ void rpl_control_delete_dodag_root(rpl_domain_t *domain, rpl_dodag_t *dodag)
 {
     (void)domain;
 
-    rpl_delete_dodag(dodag);
+    rpl_delete_dodag_root(dodag);
 }
 
 void rpl_control_update_dodag_route(rpl_dodag_t *dodag, const uint8_t *prefix, uint8_t prefix_len, uint8_t flags, uint32_t lifetime, bool age)

source/RPL/rpl_upward.c

@@ -542,6 +542,14 @@ void rpl_delete_dodag_version(rpl_dodag_version_t *version)
     rpl_dodag_t *dodag = version->dodag;
     rpl_instance_t *instance = dodag->instance;
 
+    if (instance->current_dodag_version == version) {
+        // Don't call rpl_instance_set_dodag_version(NULL) - that would pre-empt parent reselection,
+        // triggering poison immediately.
+        // Give parent selection a chance to select another version (but will it have any info on-hand?)
+        instance->current_dodag_version = NULL;
+        rpl_instance_trigger_parent_selection(instance, 5);
+    }
+
     ns_list_foreach_safe(rpl_neighbour_t, neighbour, &instance->candidate_neighbours) {
         if (neighbour->dodag_version == version) {
             rpl_delete_neighbour(instance, neighbour);
@@ -649,6 +657,21 @@ void rpl_delete_dodag(rpl_dodag_t *dodag)
     rpl_free(dodag, sizeof(*dodag));
 }
 
+void rpl_delete_dodag_root(rpl_dodag_t *dodag)
+{
+    // This should trigger immediate poison
+    rpl_instance_set_dodag_version(dodag->instance, NULL, RPL_RANK_INFINITE);
+    // Deleting DODAG is not ideal - we will just pick up adverts from our
+    // former children, and recreate, possibly violating the MaxRankIncrease.
+    // Should retain DODAG version info and just unset root flag, which will
+    // limit what happens when we hear adverts.
+    // Problem is rpl_control_create_dodag_root which can't handle the
+    // case where DODAG already exists. This would always be a problem if
+    // we'd heard adverts in between delete and create, but would be an instant
+    // problem without this delete. Need to fix.
+    rpl_delete_dodag(dodag);
+}
+
 /* Convert RPL configuration to generic trickle parameters. Returns true if
  * the value in the generic object has changed.
  */

source/RPL/rpl_upward.h

@@ -88,6 +88,7 @@ void rpl_instance_slow_timer(rpl_instance_t *instance, uint16_t seconds);
 rpl_dodag_t *rpl_lookup_dodag(const rpl_instance_t *instance, const uint8_t *dodagid);
 rpl_dodag_t *rpl_create_dodag(rpl_instance_t *instance, const uint8_t *dodagid, uint8_t g_mop_prf);
 void rpl_delete_dodag(rpl_dodag_t *dodag);
+void rpl_delete_dodag_root(rpl_dodag_t *dodag);
 uint8_t rpl_dodag_mop(const rpl_dodag_t *dodag);
 void rpl_dodag_set_root(rpl_dodag_t *dodag, bool root);
 #ifdef HAVE_RPL_ROOT

test/nanostack/unittest/stub/rpl_upward_stub.c

@@ -238,6 +238,9 @@ rpl_dodag_version_t *rpl_create_dodag_version(rpl_dodag_t *dodag, uint8_t versio
 void rpl_delete_dodag_version(rpl_dodag_version_t *version)
 {
 }
+void rpl_delete_dodag_root(rpl_dodag_t *dodag)
+{
+}
 
 bool rpl_dodag_version_is_current(const rpl_dodag_version_t *version)
 {