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 November 8, 2021 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 , 51subsequent nodes are 52.Pa /dev/ngd1 , /dev/ngd2 , 53etc. 54.Sh HOOKS 55A 56.Nm device 57node has a single hook with an arbitrary name. 58All data coming in over the hook will be presented to the device 59for 60.Xr read 2 . 61All data coming in from the device entry by 62.Xr write 2 63will be forwarded to the hook. 64.Sh CONTROL MESSAGES 65The 66.Nm device 67node supports the generic control messages, plus the following: 68.Bl -tag -width 3n 69.It Dv NGM_DEVICE_GET_DEVNAME 70Returns the device name corresponding to the node. 71.It Dv NGM_DEVICE_ETHERALIGN 72Apply the system ETHER_ALIGN offset to mbufs sent out the node's hook, 73if running on an architecture that requires strict alignment. 74Use this option when the data being injected via the device node ultimately 75ends up being fed into the protocol stack as ethernet packets (e.g., via 76an 77.Xr ng_eiface 4 78node). 79.El 80.\" Additionally, the node accepts 81.\" .Xr ioctl 2 Ns s 82.\" from the device entry. 83.\" These will be encapsulated into 84.\" .Xr netgraph 4 85.\" messages and send out to the hook. 86.Sh SHUTDOWN 87This node shuts down upon receipt of a 88.Dv NGM_SHUTDOWN 89control message, or upon hook disconnection. 90The associated device entry is removed and becomes available 91for use by future 92.Nm device 93nodes. 94.Sh SEE ALSO 95.Xr netgraph 4 , 96.Xr ngctl 8 97.Sh HISTORY 98The 99.Nm device 100node type was first implemented in 101.Fx 5.0 . 102.Sh AUTHORS 103.An Mark Santcroos Aq Mt marks@ripe.net 104.An Gleb Smirnoff Aq Mt glebius@FreeBSD.org 105