RE_CSUM_FEATURES
if (((*m_head)->m_pkthdr.csum_flags & RE_CSUM_FEATURES) != 0) {
if_sethwassistbits(ifp, 0, (RE_CSUM_FEATURES | CSUM_TSO));
if_sethwassistbits(ifp, RE_CSUM_FEATURES, 0);
if_sethwassistbits(ifp, 0, RE_CSUM_FEATURES);