XMIT_CSUM_ENC_V4
#define XMIT_CSUM_ENC (XMIT_CSUM_ENC_V4 | XMIT_CSUM_ENC_V6)
rc |= XMIT_CSUM_ENC_V4;
if (xmit_type & XMIT_CSUM_ENC_V4) {