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A node that creates a device entry in /dev (yay devfs)

Browse Source 
so that /dev/mumble can be the entrypoint to some networking graph,
e.g. a tunnel or a remote tape drive or whatever...

Not fully tested (by me) yet.

Submitted by:	Mark Santcroos <marks@ripe.net>
MFC after:	3 weeks
This commit is contained in:
Julian Elischer 2002-06-18 21:32:33 +00:00
parent d8dbc77c56
commit a835396035
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=98402
5 changed files with 798 additions and 0 deletions
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109
share/man/man4/ng_device.4 Normal file
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.\" Copyright (c) 2002 Mark Santcroos <marks@ripe.net>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. The name of the author may not be used to endorse or promote products
.\" derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd June 15, 2002
.Dt NG_DEVICE 4
.Os
.Sh NAME
.Nm ng_device
.Nd device netgraph node type
.Sh SYNOPSIS
.In netgraph/ng_device.h
.Sh DESCRIPTION
A
.Nm device
node is both a netgraph node and a system device interface. When an
.Nm device
node is created, a new device entry appears which is accessible via the
regular file operators such as
.Xr open 2 ,
.Xr close 2 ,
.Xr read 2 ,
.Xr write 2 , etc.
.Pp
The first node is created as /dev/ngd0, all subsequent nodes /dev/ngd1,
/dev/ngd2, etc. The only way a
.Nm device
node can be created is by a connection to the main
.Nm device
node by another type of
.Xr netgraph 4
node.
.Pp
When a node is shut down, the corresponding device is removed
and the device name becomes available for reuse by future
.Nm device
nodes.
.Pp
A
.Nm device
node has a single hook to which it connects to the requesting
.Xr netgraph 4
node. All data coming in over the hook will be presented to the device
for
.Xr read 2 .
All data coming in from the device entry by
.Xr write 2
will be forwarded to the hook.
.Sh HOOKS
The
.Nm device
node has no named hooks. There is one hook which is used for all
interactions. This is the hook created by the calling node.
.Sh CONTROL MESSAGES
The
.Nm device
node supports no special control messages. All incoming messages from the
hook will be returned to the sender.
Additionally the node accepts
.Xr ioctl 2 's from the device entry. These will be encapsulated into
.Xr netgraph 4
messages and send out to the hook.
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message. The associated interface is removed and becomes available
for use by future
.Nm device
nodes.
.Pp
Unlike most other node types, a
.Nm iface
node does
.Em not
go away when all hooks have been disconnected; rather, and explicit
.Dv NGM_SHUTDOWN
control message is required.
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr ngctl 8
.Sh HISTORY
The
.Nm device
node type was first implemented in
.Fx 5.0 .
.Sh AUTHORS
.An Mark Santcroos Aq marks@ripe.net

1
sys/conf/files
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@ -1112,6 +1112,7 @@ netgraph/ng_bpf.c optional netgraph_bpf
net/bpf_filter.c optional netgraph_bpf
netgraph/ng_bridge.c optional netgraph_bridge
netgraph/ng_cisco.c optional netgraph_cisco
netgraph/ng_device.c optional netgraph_device
netgraph/ng_echo.c optional netgraph_echo
netgraph/ng_ether.c optional netgraph_ether
netgraph/ng_frame_relay.c optional netgraph_frame_relay

7
sys/modules/netgraph/device/Makefile Normal file
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# $FreeBSD$
KMOD= ng_device
SRCS= ng_device.c
SRCS+= device_if.h
.include <bsd.kmod.mk>

637
sys/netgraph/ng_device.c Normal file
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/*
* Copyright (c) 2002 Mark Santcroos <marks@ripe.net>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Netgraph "device" node
*
* This node presents a /dev/ngd%d device that interfaces to an other
* netgraph node.
*
* $FreeBSD$
*
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/uio.h>
#include <sys/queue.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/poll.h>
#include <sys/ioccom.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include "ng_device.h"
/* turn this on for verbose messages */
#define NGD_DEBUG
/* Netgraph methods */
static ng_constructor_t ng_device_cons;
static ng_rcvmsg_t ng_device_rcvmsg;
static ng_newhook_t ng_device_newhook;
static ng_connect_t ng_device_connect;
static ng_rcvdata_t ng_device_rcvdata;
static ng_disconnect_t ng_device_disconnect;
static int ng_device_mod_event(module_t mod, int event, void *data);
static int ng_device_init(void);
static int get_free_unit(void);
/* Netgraph type */
static struct ng_type typestruct = {
NG_ABI_VERSION, /* version */
NG_DEVICE_NODE_TYPE, /* name */
ng_device_mod_event, /* modevent */
ng_device_cons, /* constructor */
ng_device_rcvmsg, /* receive msg */
NULL, /* shutdown */
ng_device_newhook, /* newhook */
NULL, /* findhook */
ng_device_connect, /* connect */
ng_device_rcvdata, /* receive data */
ng_device_disconnect, /* disconnect */
NULL
};
NETGRAPH_INIT(device, &typestruct);
/* per hook data */
struct ngd_connection {
SLIST_ENTRY(ngd_connection) links;
dev_t ngddev;
struct ng_hook *active_hook;
char *readq;
int loc;
int unit;
};
/* global data */
struct ngd_softc {
SLIST_HEAD(, ngd_connection) head;
node_p node;
char nodename[NG_NODELEN + 1];
} ngd_softc;
/* helper definition */
#define MIN(a, b) ((a) < (b) ? (a) : (b))
/* the per connection receiving queue maximum */
#define NGD_QUEUE_SIZE (1024*10)
/* Maximum number of NGD devices */
#define MAX_NGD 25 /* should be more than enough for now */
static d_close_t ngdclose;
static d_open_t ngdopen;
static d_read_t ngdread;
static d_write_t ngdwrite;
static d_ioctl_t ngdioctl;
static d_poll_t ngdpoll;
#define NGD_CDEV_MAJOR 20
static struct cdevsw ngd_cdevsw = {
/* open */ ngdopen,
/* close */ ngdclose,
/* read */ ngdread,
/* write */ ngdwrite,
/* ioctl */ ngdioctl,
/* poll */ ngdpoll,
/* mmap */ nommap,
/* strategy */ nostrategy,
/* name */ "ngd",
/* maj */ NGD_CDEV_MAJOR,
/* dump */ nodump,
/* psize */ nopsize,
/* flags */ 0,
};
/*
* this holds all the stuff that should be done at load time
*/
static int
ng_device_mod_event(module_t mod, int event, void *data)
{
int error = 0;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
switch (event) {
case MOD_LOAD:
ng_device_init();
break;
case MOD_UNLOAD:
/* XXX do we need to do something specific ? */
/* ng_device_breakdown */
break;
default:
error = EOPNOTSUPP;
break;
}
return(error);
}
static int
ng_device_init()
{
struct ngd_softc *sc = &ngd_softc;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
SLIST_INIT(&sc->head);
if (ng_make_node_common(&typestruct, &sc->node) != 0) {
printf("%s(): ng_make_node_common failed\n",__func__);
return(ENXIO);
}
sprintf(sc->nodename, "%s", NG_DEVICE_NODE_TYPE);
if (ng_name_node(sc->node, sc->nodename)) {
NG_NODE_UNREF(sc->node); /* make it go away again */
printf("%s(): ng_name_node failed\n",__func__);
return(ENXIO);
}
NG_NODE_SET_PRIVATE(sc->node, sc);
return(0);
}
/*
* don't allow to be created, only the device can do that
*/
static int
ng_device_cons(node_p node)
{
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
return(EINVAL);
}
/*
* Receive control message. We just bounce it back as a reply.
*/
static int
ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
struct ngd_softc *sc = &ngd_softc;
struct ng_mesg *msg;
int error = 0;
struct ngd_connection * connection = NULL;
struct ngd_connection *tmp = NULL;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
NGI_GET_MSG(item, msg);
SLIST_FOREACH(tmp,&sc->head,links) {
if(tmp->active_hook == lasthook) {
connection = tmp;
}
}
if(connection == NULL) {
printf("%s(): connection is still NULL, no hook found\n",__func__);
return(-1);
}
return(error);
}
static int
get_free_unit()
{
struct ngd_connection *tmp = NULL;
struct ngd_softc *sc = &ngd_softc;
int n = 0;
int unit = -1;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
/* When there is no list yet, the first device unit is always 0. */
if SLIST_EMPTY(&sc->head) {
unit = 0;
return(unit);
}
/* Just do a brute force loop to find the first free unit that is
* smaller than MAX_NGD.
* Set MAX_NGD to a large value, doesn't impact performance.
*/
for(n = 0;n<MAX_NGD && unit == -1;n++) {
SLIST_FOREACH(tmp,&sc->head,links) {
if(tmp->unit == n) {
unit = -1;
break;
}
unit = n;
}
}
return(unit);
}
/*
* incoming hook
*/
static int
ng_device_newhook(node_p node, hook_p hook, const char *name)
{
struct ngd_softc *sc = &ngd_softc;
struct ngd_connection * new_connection = NULL;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
new_connection = malloc(sizeof(struct ngd_connection), M_DEVBUF, M_NOWAIT);
if(new_connection == NULL) {
printf("%s(): ERROR: new_connection == NULL\n",__func__);
return(-1);
}
new_connection->unit = get_free_unit();
if(new_connection->unit<0) {
printf("%s: No free unit found by get_free_unit(), "
"increas MAX_NGD\n",__func__);
return(-1);
}
new_connection->ngddev = make_dev(&ngd_cdevsw, new_connection->unit, 0, 0,0600,"ngd%d",new_connection->unit);
if(new_connection->ngddev == NULL) {
printf("%s(): make_dev failed\n",__func__);
return(-1);
}
new_connection->readq = malloc(sizeof(char)*NGD_QUEUE_SIZE, M_DEVBUF, M_NOWAIT | M_ZERO);
if(new_connection->readq == NULL) {
printf("%s(): readq malloc failed\n",__func__);
return(-1);
}
/* point to begin of buffer */
new_connection->loc = 0;
new_connection->active_hook = hook;
SLIST_INSERT_HEAD(&sc->head, new_connection, links);
return(0);
}
/*
* we gave ok to a new hook
* now connect
*/
static int
ng_device_connect(hook_p hook)
{
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
return(0);
}
/*
* Receive data from hook
*/
static int
ng_device_rcvdata(hook_p hook, item_p item)
{
struct mbuf *m;
struct ngd_softc *sc = &ngd_softc;
struct ngd_connection * connection = NULL;
struct ngd_connection * tmp;
char *buffer;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
SLIST_FOREACH(tmp,&sc->head,links) {
if(tmp->active_hook == hook) {
connection = tmp;
}
}
if(connection == NULL) {
printf("%s(): connection is still NULL, no hook found\n",__func__);
return(-1);
}
NGI_GET_M(item, m);
NG_FREE_ITEM(item);
m = m_pullup(m,m->m_len);
if(m == NULL) {
printf("%s(): ERROR: m_pullup failed\n",__func__);
return(-1);
}
buffer = malloc(sizeof(char)*m->m_len, M_DEVBUF, M_NOWAIT | M_ZERO);
if(buffer == NULL) {
printf("%s(): ERROR: buffer malloc failed\n",__func__);
return(-1);
}
buffer = mtod(m,char *);
if( (connection->loc+m->m_len) < NGD_QUEUE_SIZE) {
memcpy(connection->readq+connection->loc, buffer, m->m_len);
connection->loc += m->m_len;
} else
printf("%s(): queue full, first read out a bit\n",__func__);
free(buffer,M_DEVBUF);
return(0);
}
/*
* Removal of the last link destroys the node
*/
static int
ng_device_disconnect(hook_p hook)
{
struct ngd_softc *sc = &ngd_softc;
struct ngd_connection * connection = NULL;
struct ngd_connection * tmp;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
SLIST_FOREACH(tmp,&sc->head,links) {
if(tmp->active_hook == hook) {
connection = tmp;
}
}
if(connection == NULL) {
printf("%s(): connection is still NULL, no hook found\n",__func__);
return(-1);
}
free(connection->readq,M_DEVBUF);
destroy_dev(connection->ngddev);
SLIST_REMOVE(&sc->head,connection,ngd_connection,links);
return(0);
}
/*
* the device is opened
*/
static int
ngdopen(dev_t dev, int flag, int mode, struct thread *td)
{
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
return(0);
}
/*
* the device is closed
*/
static int
ngdclose(dev_t dev, int flag, int mode, struct thread *td)
{
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif
return(0);
}
/*
* process ioctl
*
* they are translated into netgraph messages and passed on
*
*/
static int
ngdioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
{
struct ngd_softc *sc = &ngd_softc;
struct ngd_connection * connection = NULL;
struct ngd_connection * tmp;
int error = 0;
struct ng_mesg *msg;
struct ngd_param_s * datap;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
SLIST_FOREACH(tmp,&sc->head,links) {
if(tmp->ngddev == dev) {
connection = tmp;
}
}
if(connection == NULL) {
printf("%s(): connection is still NULL, no dev found\n",__func__);
return(-1);
}
/* NG_MKMESSAGE(msg, cookie, cmdid, len, how) */
NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
M_NOWAIT);
if (msg == NULL) {
printf("%s(): msg == NULL\n",__func__);
goto nomsg;
}
/* pass the ioctl data into the ->data area */
datap = (struct ngd_param_s *)msg->data;
datap->p = addr;
/* NG_SEND_MSG_HOOK(error, here, msg, hook, retaddr) */
NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, NULL);
if(error)
printf("%s(): NG_SEND_MSG_HOOK error: %d\n",__func__,error);
nomsg:
return(0);
}
/*
* This function is called when a read(2) is done to our device.
* We pass the data available in kernelspace on into userland using
* uiomove.
*/
static int
ngdread(dev_t dev, struct uio *uio, int flag)
{
int ret = 0, amnt;
char buffer[uio->uio_resid+1];
struct ngd_softc *sc = &ngd_softc;
struct ngd_connection * connection = NULL;
struct ngd_connection * tmp;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
SLIST_FOREACH(tmp,&sc->head,links) {
if(tmp->ngddev == dev) {
connection = tmp;
}
}
if(connection == NULL) {
printf("%s(): connection is still NULL, no dev found\n",__func__);
return(-1);
}
while ( ( uio->uio_resid > 0 ) && ( connection->loc > 0 ) ) {
amnt = MIN(uio->uio_resid,connection->loc);
memcpy(buffer,connection->readq, amnt);
memcpy(connection->readq, connection->readq+amnt,
connection->loc-amnt);
connection->loc -= amnt;
ret = uiomove((caddr_t)buffer, amnt, uio);
if(ret != 0)
goto error;
}
return(0);
error:
printf("%s(): uiomove returns error %d\n",__func__,ret);
/* do error cleanup here */
return(ret);
}
/*
* This function is called when our device is written to.
* We read the data from userland into our local buffer and pass it on
* into the remote hook.
*
*/
static int
ngdwrite(dev_t dev, struct uio *uio, int flag)
{
int ret;
int error = 0;
struct mbuf *m;
char buffer[uio->uio_resid];
int len = uio->uio_resid;
struct ngd_softc *sc =& ngd_softc;
struct ngd_connection * connection = NULL;
struct ngd_connection * tmp;
#ifdef NGD_DEBUG
printf("%s()\n",__func__);
#endif /* NGD_DEBUG */
SLIST_FOREACH(tmp,&sc->head,links) {
if(tmp->ngddev == dev) {
connection = tmp;
}
}
if(connection == NULL) {
printf("%s(): connection is still NULL, no dev found\n",__func__);
return(-1);
}
if (len > 0) {
if ((ret = uiomove((caddr_t)buffer, len, uio)) != 0)
goto error;
} else
printf("%s(): len <= 0 : is this supposed to happen?!\n",__func__);
m = m_devget(buffer,len,0,NULL,NULL);
NG_SEND_DATA_ONLY(error,connection->active_hook,m);
return(0);
error:
/* do error cleanup here */
printf("%s(): uiomove returned err: %d\n",__func__,ret);
return(ret);
}
/*
* we are being polled/selected
* check if there is data available for read
*/
static int
ngdpoll(dev_t dev, int events, struct thread *td)
{
int revents = 0;
struct ngd_softc *sc = &ngd_softc;
struct ngd_connection * connection = NULL;
struct ngd_connection * tmp;
if (events & (POLLIN | POLLRDNORM)) {
/* get the connection we have to know the loc from */
SLIST_FOREACH(tmp,&sc->head,links) {
if(tmp->ngddev == dev) {
connection = tmp;
}
}
if(connection == NULL) {
printf("%s(): ERROR: connection is still NULL,"
"no dev found\n",__func__);
return(-1);
}
if (connection->loc > 0)
revents |= events & (POLLIN | POLLRDNORM);
}
return(revents);
}

44
sys/netgraph/ng_device.h Normal file
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@ -0,0 +1,44 @@
/*
* Copyright (c) 2002 Mark Santcroos <marks@ripe.net>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* $FreeBSD$
*
*/
#ifndef _NETGRAPH_DEVICE_H_
#define _NETGRAPH_DEVICE_H_
/* Node type name and magic cookie */
#define NG_DEVICE_NODE_TYPE "device"
#define NGM_DEVICE_COOKIE 1009920473
/* passing ioctl params */
struct ngd_param_s {
void * p;
};
#endif /* _NETGRAPH_DEVICE_H_ */