skb_cow_data — Check that a socket buffer's data buffers are writable
int fsfuncskb_cow_data ( | struct sk_buff * skb, |
| int tailbits, | |
struct sk_buff ** trailer); |
skbThe socket buffer to check.
tailbitsAmount of trailing space to be added
trailer
Returned pointer to the skb where the tailbits space begins
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.