__IPV6_TCLASS_FROM_FLOW
dscp = __IPV6_TCLASS_FROM_FLOW(ip6_hdr->ip6_vcf);
header->dsfield = __IPV6_TCLASS_FROM_FLOW(ip6h->ip6_vcf);
packet->dsfield = __IPV6_TCLASS_FROM_FLOW(ip6h->ip6_vcf);
dscp = __IPV6_TCLASS_FROM_FLOW(ip6_hdr->ip6_vcf);