Pass client to some core functions to make it possible to check
permissions when iterating globals.
Check permissions of factory before using it.
Check permissions in link factory, only allow linking of nodes we can
see.
Check permissions in the autolink module, only try to link to nodes
we can see.
Make client permissions update behave like an atomic update of an
unordered set of permissions, which is perhaps a bit more intuitive.
Don't unlink the ports of an inactive link because then it might be
possible that the scheduler can't recycle a buffer, instead use
a port flag to mark the ports disabled and change to scheduler to
skip those ports.
Make a method to find the memory block for the given ptr. We can
use this to find the memfd of the memory if there is any. We can
then remove the Shared metadata on buffers.
ringbuffer: remove size and mask from the ringbuffer, we have that
elsewhere in the user of the ringbuffer.
Remove the buffer data offset and size fields and replace with a
ringbuffer. We then have a ringbuffer in all buffer data, which
simplifies things.
We can now remove the ringbuffer metadata.
