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.Dd November 8, 2021 26.Dt NG_DEVICE 4 27.Os 28.Sh NAME 29.Nm ng_device 30.Nd device netgraph node type 31.Sh SYNOPSIS 32.In netgraph/ng_device.h 33.Sh DESCRIPTION 34A 35.Nm device 36node is both a netgraph node and a system device interface. 37When a 38.Nm device 39node is created, a new device entry appears which is accessible via the 40regular file operators such as 41.Xr open 2 , 42.Xr close 2 , 43.Xr read 2 , 44.Xr write 2 , 45etc. 46.Pp 47The first node is created as 48.Pa /dev/ngd0 , 49subsequent nodes are 50.Pa /dev/ngd1 , /dev/ngd2 , 51etc. 52.Sh HOOKS 53A 54.Nm device 55node has a single hook with an arbitrary name. 56All data coming in over the hook will be presented to the device 57for 58.Xr read 2 . 59All data coming in from the device entry by 60.Xr write 2 61will be forwarded to the hook. 62.Sh CONTROL MESSAGES 63The 64.Nm device 65node supports the generic control messages, plus the following: 66.Bl -tag -width 3n 67.It Dv NGM_DEVICE_GET_DEVNAME 68Returns the device name corresponding to the node. 69.It Dv NGM_DEVICE_ETHERALIGN 70Apply the system ETHER_ALIGN offset to mbufs sent out the node's hook, 71if running on an architecture that requires strict alignment. 72Use this option when the data being injected via the device node ultimately 73ends up being fed into the protocol stack as ethernet packets (e.g., via 74an 75.Xr ng_eiface 4 76node). 77.El 78.\" Additionally, the node accepts 79.\" .Xr ioctl 2 Ns s 80.\" from the device entry. 81.\" These will be encapsulated into 82.\" .Xr netgraph 4 83.\" messages and send out to the hook. 84.Sh SHUTDOWN 85This node shuts down upon receipt of a 86.Dv NGM_SHUTDOWN 87control message, or upon hook disconnection. 88The associated device entry is removed and becomes available 89for use by future 90.Nm device 91nodes. 92.Sh SEE ALSO 93.Xr netgraph 4 , 94.Xr ngctl 8 95.Sh HISTORY 96The 97.Nm device 98node type was first implemented in 99.Fx 5.0 . 100.Sh AUTHORS 101.An Mark Santcroos Aq Mt marks@ripe.net 102.An Gleb Smirnoff Aq Mt glebius@FreeBSD.org 103