When a transition from link alive to link dead configuration or vice
versa occurs, notify any upstream and / or downstream peers using
NGM_FLOW messagges.
Link state notification using NGM_FLOW messages is modelled around
around already existing code in ng_ether.c.
MFC after: 3 days
to provide serialization of calls into the node, which is accomplished
by markng the node as single-threaded (NGF_FORCE_WRITER).
The price we pay is that each ng_pipe instance now has its own callout
handler which polls for queued frames on each clock tick, as long as
the pipe has any frames in its internal queues. OTOH, we got rid of
the global ng_pipe mutex, so from now on multiple ng_pipe instances
can operate in parallel. This change also fixes counting of forwarded
frames when an ng_pipe node is not enforcing any packet impairments.
While here, attempt to improve adherance to style(9) throughout
otherwise mostly unreadable code.
MFC after: 3 days
vnet.h, we now use jails (rather than vimages) as the abstraction
for virtualization management, and what remained was specific to
virtual network stacks. Minor cleanups are done in the process,
and comments updated to reflect these changes.
Reviewed by: bz
Approved by: re (vimage blanket)
