Provided by: freebsd-manpages_11.1-3_all 
NAME
ng_UI — UI netgraph node type
SYNOPSIS
#include <netgraph/ng_UI.h>
DESCRIPTION
The UI node type has two hooks, upstream and downstream. Packets received on downstream must have 0x03
(indicating unnumbered information) as their first byte; if not the packet is dropped. This byte is then
stripped and the remainder of the packet sent out on upstream.
Conversely, packets received on upstream will have a 0x03 byte prepended to them before being forwarded out
on the downstream hook.
HOOKS
This node type supports the following hooks:
downstream Downstream connection. Packets on this side of the node have a 0x03 as their first byte.
upstream Upstream connection. Packets on this side of the node have the initial 0x03 byte stripped off.
CONTROL MESSAGES
This node type supports only the generic control messages.
SHUTDOWN
This node shuts down upon receipt of a NGM_SHUTDOWN control message, or when both hooks have been
disconnected.
SEE ALSO
netgraph(4), ngctl(8)
HISTORY
The ng_UI node type was implemented in FreeBSD 4.0.
AUTHORS
Julian Elischer <julian@FreeBSD.org>