skb_ip_make_writable and skbs not owned by a socket

[David S. Miller]

On Sun, 02 Jan 2005 22:19:45 +0100
Patrick McHardy <kaber at trash.net> wrote:

> skb_ip_make_writable copies the packet as soon as the data area needs
> to be touched. This is of course necessary for packets generated locally,
> but can't we mangle the data area of skbs with skb->sk == NULL without
> copying them ?

Not if they are cloned.  tcpdump can still share access to the
packet.