vtnet_rx_header
framesz = sizeof(struct vtnet_rx_header);
struct vtnet_rx_header *rxhdr =
mtod(m, struct vtnet_rx_header *);
m->m_len - sizeof(struct vtnet_rx_header));
adjsz = sizeof(struct vtnet_rx_header);
sc->vtnet_rx_nmbufs = howmany(sizeof(struct vtnet_rx_header) +