struct sk_buff * pskb_copy (struct sk_buff * skb, int gfp_mask);
Make a copy of both an &sk_buff and part of its data, located in header. Fragmented data remain shared. This is used when the caller wishes to modify only header of &sk_buff and needs private copy of the header to alter. Returns NULL on failure or the pointer to the buffer on success. The returned buffer has a reference count of 1.