sk_skb_cb
offsetof(struct sk_skb_cb, strp));
offsetof(struct sk_skb_cb, temp_reg);
BUILD_BUG_ON(sizeof_field(struct sk_skb_cb, data) < 20);
offsetof(struct sk_skb_cb, data)) %
off += offsetof(struct sk_skb_cb, data);
offsetof(struct sk_skb_cb, strp));
BUILD_BUG_ON(sizeof(struct sk_skb_cb) >
struct sk_skb_cb *scb = (struct sk_skb_cb *)skb->cb;