1.\" Copyright (c) 2002 Mark Santcroos <marks@ripe.net> 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright 9.\" notice, this list of conditions and the following disclaimer in the 10.\" documentation and/or other materials provided with the distribution. 11.\" 3. The name of the author may not be used to endorse or promote products 12.\" derived from this software without specific prior written permission. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd June 15, 2002 28.Dt NG_DEVICE 4 29.Os 30.Sh NAME 31.Nm ng_device 32.Nd device netgraph node type 33.Sh SYNOPSIS 34.In netgraph/ng_device.h 35.Sh DESCRIPTION 36A 37.Nm device 38node is both a netgraph node and a system device interface. 39When a 40.Nm device 41node is created, a new device entry appears which is accessible via the 42regular file operators such as 43.Xr open 2 , 44.Xr close 2 , 45.Xr read 2 , 46.Xr write 2 , 47etc. 48.Pp 49The first node is created as 50.Pa /dev/ngd0 , 51all subsequent nodes 52.Pa /dev/ngd1 , /dev/ngd2 , 53etc. 54The only way a 55.Nm device 56node can be created is by a connection to the main 57.Nm device 58node by another type of 59.Xr netgraph 4 60node. 61.Pp 62When a node is shut down, the corresponding device is removed 63and the device name becomes available for reuse by future 64.Nm device 65nodes. 66.Pp 67A 68.Nm device 69node has a single hook to which it connects to the requesting 70.Xr netgraph 4 71node. 72All data coming in over the hook will be presented to the device 73for 74.Xr read 2 . 75All data coming in from the device entry by 76.Xr write 2 77will be forwarded to the hook. 78.Sh HOOKS 79The 80.Nm device 81node has no named hooks. 82There is one hook which is used for all interactions. 83This is the hook created by the calling node. 84.Sh CONTROL MESSAGES 85The 86.Nm device 87node supports no special control messages. 88All incoming messages from the 89hook will be returned to the sender. 90Additionally the node accepts 91.Xr ioctl 2 Ns s 92from the device entry. 93These will be encapsulated into 94.Xr netgraph 4 95messages and send out to the hook. 96.Sh SHUTDOWN 97This node shuts down upon receipt of a 98.Dv NGM_SHUTDOWN 99control message. 100The associated interface is removed and becomes available 101for use by future 102.Nm device 103nodes. 104.Pp 105Unlike most other node types, a 106.Nm device 107node does 108.Em not 109go away when all hooks have been disconnected; rather, an explicit 110.Dv NGM_SHUTDOWN 111control message is required. 112.Sh SEE ALSO 113.Xr netgraph 4 , 114.Xr ngctl 8 115.Sh HISTORY 116The 117.Nm device 118node type was first implemented in 119.Fx 5.0 . 120.Sh AUTHORS 121.An Mark Santcroos Aq marks@ripe.net 122