Provided by: linux-doc-2.6.15_2.6.15-23.39_all bug

NAME

       skb_cow - copy header of skb when it is required

SYNOPSIS

       int skb_cow  (struct sk_buff * skb, unsigned int headroom);

ARGUMENTS

       skb    buffer to cow

       headroom
              needed headroom

DESCRIPTION

       If the skb passed lacks sufficient headroom or its data part is shared,
       data is reallocated. If reallocation fails, an error  is  returned  and
       original skb is not changed.

       The result is skb with writable area skb->head...skb->tail and at least
       headroom of space at head.