IP_FLAG_DONT_FRAGMENT
(protocol->flags & IP_FLAG_DONT_FRAGMENT) != 0);
protocol->flags |= IP_FLAG_DONT_FRAGMENT;
protocol->flags &= ~IP_FLAG_DONT_FRAGMENT;
if ((protocol->flags & IP_FLAG_DONT_FRAGMENT) != 0)
if (protocol != NULL && (protocol->flags & IP_FLAG_DONT_FRAGMENT) != 0)