+ dhcp_transaction_t *transaction;
+
+ if (!vip)
+ {
+ return NULL;
+ }
+ this->mutex->lock(this->mutex);
+ transaction = this->transactions->get(this->transactions,
+ (void*)hash_id_host(id, vip));
+ if (!transaction)
+ {
+ this->mutex->unlock(this->mutex);
+ return NULL;
+ }
+ return enumerator_create_cleaner(
+ transaction->create_attribute_enumerator(transaction),
+ (void*)this->mutex->unlock, this->mutex);