static unsigned long bpf_skb_copy(void *dst_buff, const void *skb,
				  unsigned long off, unsigned long len)
{
	void *ptr = skb_header_pointer(skb, off, len, dst_buff);

	if (unlikely(!ptr))
		return len;
	if (ptr != dst_buff)
		memcpy(dst_buff, ptr, len);

	return 0;
}
Unknown