centos man page for build_skb

BUILD_SKB(9)							 Linux Networking						      BUILD_SKB(9)

NAME
       build_skb - build a network buffer

SYNOPSIS
       struct sk_buff * build_skb(void * data, unsigned int frag_size);

ARGUMENTS
       data
	   data buffer provided by caller

       frag_size
	   size of fragment, or 0 if head was kmalloced

DESCRIPTION
       Allocate a new sk_buff. Caller provides space holding head and skb_shared_info.	data must have been allocated by kmalloc The return is the
       new skb buffer. On a failure the return is NULL, and data is not freed.

NOTES
       Before IO, driver allocates only data buffer where NIC put incoming frame Driver should add room at head (NET_SKB_PAD) and MUST add room at
       tail (SKB_DATA_ALIGN(skb_shared_info)) After IO, driver calls build_skb, to allocate sk_buff and populate it before giving packet to stack.
       RX rings only contains data buffers, not full skbs.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							      BUILD_SKB(9)