debian man page for ng_h4

NG_H4(4)						   BSD Kernel Interfaces Manual 						  NG_H4(4)

NAME
     ng_h4 -- Netgraph node type that is also an H4 line discipline

SYNOPSIS
     #include <sys/types.h>
     #include <netgraph/bluetooth/include/ng_h4.h>

DESCRIPTION
     The h4 node type is both a persistent Netgraph node type and a H4 line discipline.  It implements a Bluetooth HCI UART transport layer as per
     chapter H4 of the Bluetooth Specification Book v1.1.  A new node is created when the corresponding line discipline, H4DISC, is registered on
     a tty device (see tty(4)).

     The node has a single hook called hook.  Incoming bytes received on the tty device are re-assembled into HCI frames (according to the
     length).  Full HCI frames are sent out on the hook.  HCI frames received on hook are transmitted out on the tty device.  No modification to
     the data is performed in either direction.  While the line discipline is installed on a tty, the normal read and write operations are
     unavailable, returning EIO.

     Information about the node is available via the netgraph ioctl(2) command NGIOCGINFO.  This command returns a struct nodeinfo similar to the
     NGM_NODEINFO netgraph(4) control message.

HOOKS
     This node type supports the following hooks:

     hook    single HCI frame contained in single mbuf structure.

CONTROL MESSAGES
     This node type supports the generic control messages, plus the following:

     NGM_H4_NODE_RESET
	     Reset the node.

     NGM_H4_NODE_GET_STATE
	     Returns current receiving state for the node.

     NGM_H4_NODE_GET_DEBUG
	     Returns an integer containing the current debug level for the node.

     NGM_H4_NODE_SET_DEBUG
	     This command takes an integer argument and sets current debug level for the node.

     NGM_H4_NODE_GET_QLEN
	     Returns current length of outgoing queue for the node.

     NGM_H4_NODE_SET_QLEN
	     This command takes an integer argument and sets maximum length of outgoing queue for the node.

     NGM_H4_NODE_GET_STAT
	     Returns various statistic information for the node, such as: number of bytes (frames) sent, number of bytes (frames) received and
	     number of input (output) errors.

     NGM_H4_NODE_RESET_STAT
	     Reset all statistic counters to zero.

SHUTDOWN
     This node shuts down when the corresponding device is closed (or the line discipline is uninstalled on the device).

SEE ALSO
     ioctl(2), netgraph(4), tty(4), ngctl(8)

HISTORY
     The h4 node type was implemented in FreeBSD 5.0.

AUTHORS
     Maksim Yevmenkin <m_evmenkin@yahoo.com>

BUGS
     This node still uses spltty(9) to lock tty layer.	This is wrong.

BSD
								   June 14, 2002							       BSD