hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
hdr->csum_start = gho.l4_hdr_offset; // 0x22;
hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
hdr->csum_start = gho.l4_hdr_offset; // 0x22;
hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);