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RPL non-storing defensive link update: make sure the topology is loop-free at all times
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819916668e
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@ -122,6 +122,7 @@ rpl_ns_update_node(rpl_dag_t *dag, const uip_ipaddr_t *child, const uip_ipaddr_t
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{
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rpl_ns_node_t *child_node = rpl_ns_get_node(dag, child);
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rpl_ns_node_t *parent_node = rpl_ns_get_node(dag, parent);
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rpl_ns_node_t *old_parent_node;
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if(parent != NULL) {
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/* No node for the parent, add one with infinite lifetime */
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@ -140,6 +141,7 @@ rpl_ns_update_node(rpl_dag_t *dag, const uip_ipaddr_t *child, const uip_ipaddr_t
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if(child_node == NULL) {
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return NULL;
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}
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child_node->parent = NULL;
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list_add(nodelist, child_node);
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num_nodes++;
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}
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@ -147,9 +149,24 @@ rpl_ns_update_node(rpl_dag_t *dag, const uip_ipaddr_t *child, const uip_ipaddr_t
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/* Initialize node */
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child_node->dag = dag;
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child_node->lifetime = lifetime;
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child_node->parent = parent_node;
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memcpy(child_node->link_identifier, ((const unsigned char *)child) + 8, 8);
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/* Is the node reachable before the update? */
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if(rpl_ns_is_node_reachable(dag, child)) {
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old_parent_node = child_node->parent;
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/* Update node */
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child_node->parent = parent_node;
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/* Has the node become unreachable? May happen if we create a loop. */
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if(!rpl_ns_is_node_reachable(dag, child)) {
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/* The new parent makes the node unreachable, restore old parent.
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* We will take the update next time, with chances we know more of
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* the topology and the loop is gone. */
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child_node->parent = old_parent_node;
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}
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} else {
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child_node->parent = parent_node;
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}
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return child_node;
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}
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/*---------------------------------------------------------------------------*/
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