NG_DEVICE(4)           FreeBSD Kernel Interfaces Manual           NG_DEVICE(4)

NAME
     ng_device - device netgraph node type

SYNOPSIS
     #include <netgraph/ng_device.h>

DESCRIPTION
     A device node is both a netgraph node and a system device interface.
     When a device node is created, a new device entry appears which is
     accessible via the regular file operators such as open(2), close(2),
     read(2), write(2), etc.

     The first node is created as /dev/ngd0, subsequent nodes are /dev/ngd1,
     /dev/ngd2, etc.

HOOKS
     A device node has a single hook with an arbitrary name.  All data coming
     in over the hook will be presented to the device for read(2).  All data
     coming in from the device entry by write(2) will be forwarded to the
     hook.

CONTROL MESSAGES
     The device node supports the generic control messages, plus the
     following:

     NGM_DEVICE_GET_DEVNAME
          Returns the device name corresponding to the node.

     NGM_DEVICE_ETHERALIGN
          Apply the system ETHER_ALIGN offset to mbufs sent out the node's
          hook, if running on an architecture that requires strict alignment.
          Use this option when the data being injected via the device node
          ultimately ends up being fed into the protocol stack as ethernet
          packets (e.g., via an ng_eiface(4) node).

SHUTDOWN
     This node shuts down upon receipt of a NGM_SHUTDOWN control message, or
     upon hook disconnection.  The associated device entry is removed and
     becomes available for use by future device nodes.

SEE ALSO
     netgraph(4), ngctl(8)

HISTORY
     The device node type was first implemented in FreeBSD 5.0.

AUTHORS
     Mark Santcroos <marks@ripe.net>
     Gleb Smirnoff <glebius@FreeBSD.org>

FreeBSD 13.1-RELEASE-p6        November 8, 2021        FreeBSD 13.1-RELEASE-p6