Provided by: linux-doc-2.6.15_2.6.15-23.39_all
skb_copy_expand - copy and expand sk_buff
struct sk_buff * skb_copy_expand (const struct sk_buff * skb,
int newheadroom, int newtailroom,
skb buffer to copy
new free bytes at head
new free bytes at tail
Make a copy of both an &sk_buff and its data and while doing so
allocate additional space.
This is used when the caller wishes to modify the data and needs a
private copy of the data to alter as well as more space for new fields.
Returns NULL on failure or the pointer to the buffer on success. The
returned buffer has a reference count of 1.
You must pass GFP_ATOMIC as the allocation priority if this function is
called from an interrupt.
ip_summed is not copied. Why does this work? Is it used only by
netfilter in the cases when checksum is recalculated? --ANK