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NG_H4(4)	       FreeBSD 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 cre-
     ated 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.

FreeBSD	10.1			 June 14, 2002			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | HOOKS | CONTROL MESSAGES | SHUTDOWN | SEE ALSO | HISTORY | AUTHORS | BUGS

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