190 lines
6.2 KiB
C
190 lines
6.2 KiB
C
/* $NetBSD: if_tap_lkm.c,v 1.3 2008/04/29 05:46:09 martin Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 2003, 2004, 2005 The NetBSD Foundation.
|
|
* All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to the NetBSD Foundation
|
|
* by Quentin Garnier.
|
|
*
|
|
* 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
* ``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 FOUNDATION OR CONTRIBUTORS
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
* tap is a NetBSD Loadable Kernel Module that demonstrates the use of
|
|
* several kernel mechanisms, mostly in the networking subsytem.
|
|
*
|
|
* 1. it is example LKM, with the standard LKM management routines and
|
|
* 2. example Ethernet driver.
|
|
* 3. example of use of autoconf stuff inside a LKM.
|
|
* 4. example clonable network interface.
|
|
* 5. example sysctl interface use from a LKM.
|
|
* 6. example LKM character device, with read, write, ioctl, poll
|
|
* and kqueue available.
|
|
* 7. example cloning device, using the MOVEFD semantics.
|
|
*
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__KERNEL_RCSID(0, "$NetBSD: if_tap_lkm.c,v 1.3 2008/04/29 05:46:09 martin Exp $");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/conf.h>
|
|
#include <sys/device.h>
|
|
#include <sys/ksyms.h>
|
|
#include <sys/lkm.h>
|
|
#include <sys/sysctl.h>
|
|
|
|
#include <net/if.h>
|
|
|
|
/* autoconf(9) structures */
|
|
|
|
CFDRIVER_DECL(tap, DV_DULL, NULL);
|
|
|
|
/* LKM management routines */
|
|
|
|
int tap_lkmentry(struct lkm_table *, int, int);
|
|
static int tap_lkmload(struct lkm_table *, int);
|
|
static int tap_lkmunload(struct lkm_table *, int);
|
|
|
|
void tapattach(int);
|
|
int tapdetach(void);
|
|
SYSCTL_SETUP_PROTO(sysctl_tap_setup);
|
|
|
|
extern struct cfattach tap_ca;
|
|
extern const struct cdevsw tap_cdevsw;
|
|
extern struct if_clone tap_cloners;
|
|
static struct sysctllog *tap_log;
|
|
|
|
/*
|
|
* The type of the module is actually userland-oriented. For a
|
|
* traditional Ethernet driver, MOD_MISC would be enough since
|
|
* the userland manipulates interfaces through operations on
|
|
* sockets.
|
|
*
|
|
* Here MOD_DEV is chosen because a direct access interface is
|
|
* exposed, and the easiest way to achieve this is through a
|
|
* regular device node.
|
|
*/
|
|
|
|
MOD_DEV("tap", "tap", NULL, -1, &tap_cdevsw, -1);
|
|
|
|
/* We don't have anything to do on 'modstat' */
|
|
int
|
|
tap_lkmentry(struct lkm_table *lkmtp, int cmd, int ver)
|
|
{
|
|
DISPATCH(lkmtp, cmd, ver,
|
|
tap_lkmload, tap_lkmunload, lkm_nofunc);
|
|
}
|
|
|
|
/*
|
|
* autoconf(9) is a rather complicated piece of work, but in the end
|
|
* it is rather flexible, so you can easily add a device somewhere in
|
|
* the tree, and make almost anything attach to something known.
|
|
*
|
|
* Here the idea is taken from Jason R. Thorpe's ataraid(4) pseudo-
|
|
* device. Instead of needing a declaration in the kernel
|
|
* configuration, we teach autoconf(9) the availability of the
|
|
* pseudo-device at run time.
|
|
*
|
|
* Once our autoconf(9) structures are committed to the kernel's
|
|
* arrays, we can attach a device. It is done through config_attach
|
|
* for a real device, but for a pseudo-device it is a bit different
|
|
* and one has to use config_pseudo_attach.
|
|
*
|
|
* And since we want the user to be responsible for creating device,
|
|
* we use the interface cloning mechanism, and advertise our interface
|
|
* to the kernel.
|
|
*/
|
|
static int
|
|
tap_lkmload(struct lkm_table *lkmtp, int cmd)
|
|
{
|
|
int error = 0;
|
|
|
|
error = config_cfdriver_attach(&tap_cd);
|
|
if (error) {
|
|
aprint_error("%s: unable to register cfdriver\n",
|
|
tap_cd.cd_name);
|
|
goto out;
|
|
}
|
|
|
|
/* XXX: no way to detect an error for config_cfattach_attach() */
|
|
tapattach(1);
|
|
|
|
sysctl_tap_setup(&tap_log);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Cleaning up is the most critical part of a LKM, since a module is not
|
|
* actually made to be loadable, but rather "unloadable". If it is only
|
|
* to be loaded, you'd better link it to the kernel in the first place.
|
|
*
|
|
* The interface cloning mechanism is really simple, with only two void
|
|
* returning functions. It will always do its job. You should note though
|
|
* that if an instance of tap can't be detached, the module won't
|
|
* unload and you won't be able to create interfaces anymore.
|
|
*
|
|
* We have to make sure the devices really exist, because they can be
|
|
* destroyed through ifconfig, hence the test whether cd_devs[i] is NULL
|
|
* or not.
|
|
*
|
|
* The cd_devs array is somehow the downside of the whole autoconf(9)
|
|
* mechanism, since if you only create 'tap150', you'll get an array of
|
|
* 150 elements which 149 of them are NULL.
|
|
*/
|
|
static int
|
|
tap_lkmunload(struct lkm_table *lkmtp, int cmd)
|
|
{
|
|
int error, i;
|
|
|
|
if_clone_detach(&tap_cloners);
|
|
|
|
for (i = 0; i < tap_cd.cd_ndevs; i++)
|
|
if (tap_cd.cd_devs[i] != NULL &&
|
|
(error = config_detach(tap_cd.cd_devs[i], 0)) != 0) {
|
|
aprint_error("%s: unable to detach instance\n",
|
|
((struct device *)tap_cd.cd_devs[i])->dv_xname);
|
|
return error;
|
|
}
|
|
|
|
sysctl_teardown(&tap_log);
|
|
|
|
if ((error = config_cfattach_detach(tap_cd.cd_name,
|
|
&tap_ca)) != 0) {
|
|
aprint_error("%s: unable to deregister cfattach\n",
|
|
tap_cd.cd_name);
|
|
return error;
|
|
}
|
|
|
|
if ((error = config_cfdriver_detach(&tap_cd)) != 0) {
|
|
aprint_error("%s: unable to deregister cfdriver\n",
|
|
tap_cd.cd_name);
|
|
return error;
|
|
}
|
|
|
|
return 0;
|
|
}
|