SKB_COW_DATA(9)                          Linux Networking                         SKB_COW_DATA(9)



NAME
       skb_cow_data - Check that a socket buffer's data buffers are writable

SYNOPSIS
       int skb_cow_data(struct sk_buff * skb, int tailbits, struct sk_buff ** trailer);

ARGUMENTS
       skb
           The socket buffer to check.

       tailbits
           Amount of trailing space to be added

       trailer
           Returned pointer to the skb where the tailbits space begins

DESCRIPTION
       Make sure that the data buffers attached to a socket buffer are writable. If they are not,
       private copies are made of the data buffers and the socket buffer is set to use these
       instead.

       If tailbits is given, make sure that there is space to write tailbits bytes of data beyond
       current end of socket buffer.  trailer will be set to point to the skb in which this space
       begins.

       The number of scatterlist elements required to completely map the COW'd and extended
       socket buffer will be returned.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                           SKB_COW_DATA(9)