void freeIpTree(addr_node *root) {
  if(root == NULL)
    return;

  freeIpTree(root->left);
  freeIpTree(root->right);
  free(root);
}
void freeIpTree(addr_node *root) {
  if(root == NULL)
    return;

  freeIpTree(root->left);
  freeIpTree(root->right);
  free(root);
}