... In this article, we will look at the way the memory management and buffering is implemented for network layers and network device drivers under the existing Linux kernel, as well as explain how and why some things have changed over time. ... There are two primary sets of functions provided in the sk_buff library. ... A buffer can be told not to be freed when kfree_skb() (see below) is called. kfree_skb() releases a buffer, and if skb->sk is set it lowers the memory use counts of the socket ( sk ). ...