2.1. The Socket Buffer: sk_buff Structure2.1.1. Networking Options and Kernel Structures2.1.2. Layout Fields2.1.3. General Fields2.1.4. Feature-Specific Fields2.1.5. Management Functions2.1.5.1. Allocating memory: alloc_skb and dev_alloc_skb2.1.5.2. Freeing memory: kfree_skb and dev_kfree_skb2.1.5.3. Data reservation and alignment: skb_reserve, skb_put, skb_push, and skb_pull2.1.5.4. The skb_shared_info structure and the skb_shinfo function2.1.5.5. Cloning and copying buffers2.1.5.6. List management functions