IP6_REPLY_MARK
mark = IP6_REPLY_MARK(net, skb->mark);
u32 mark = IP6_REPLY_MARK(net, skb->mark);
fl6.flowi6_mark = IP6_REPLY_MARK(net, oldskb->mark);
.flowi6_mark = mark ? mark : IP6_REPLY_MARK(net, skb->mark),
fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark;