vtnet_rx_header
new_frame_size = sizeof(struct vtnet_rx_header) +
struct vtnet_rx_header *rxhdr;
rxhdr = (struct vtnet_rx_header *) mdata;
offset += sizeof(struct vtnet_rx_header);
adjsz = sizeof(struct vtnet_rx_header);
howmany(sizeof(struct vtnet_rx_header) + VTNET_MAX_RX_SIZE, \