function restore(fn, obj) {
  var props = new Array(arguments.length - 2);
  var vals = new Array(arguments.length - 2);

  for (var i = 0; i < props.length; i++) {
    props[i] = arguments[i + 2];
    vals[i] = obj[props[i]];
  }

  return function () {
    // restore vals
    for (var i = 0; i < props.length; i++) {
      obj[props[i]] = vals[i];
    }

    return fn.apply(this, arguments);
  };
}
Compile trust function for single subnet.

@param {Object} subnet
@private