ipv6_change_dsfield
ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
ipv6_change_dsfield(ipv6_hdr(skb), 0xff, ecn);
ipv6_change_dsfield(ipv6_hdr(skb), 0xff, ecn);
ipv6_change_dsfield(iph, 0, dsfield);
ipv6_change_dsfield(iph, 0, nv);
ipv6_change_dsfield(ipv6_hdr(skb), XT_DSCP_ECN_MASK,
ipv6_change_dsfield(nh, ~mask, ipv6_tclass);
ipv6_change_dsfield(ipv6_hdr(skb),
ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
ipv6_change_dsfield(iph, 0, XFRM_MODE_SKB_CB(skb)->tos);
ipv6_change_dsfield(top_iph, 0, dsfield);
ipv6_change_dsfield(top_iph, 0, dsfield);