vlan.c

嵌入式系统设计与实验教材二源码linux内核移植与编译

/*
 * INET		802.1Q VLAN
 *		Ethernet-type device handling.
 *
 * Authors:	Ben Greear <[e-mail]>
 *              Please send support related email to: [e-mail]
 *              VLAN Home Page: http://www.candelatech.com/~greear/vlan.html
 * 
 * Fixes:
 *              Fix for packet capture - Nick Eggleston <[e-mail]>;
 *
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */

#include <asm/uaccess.h> /* for copy_from_user */
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/datalink.h>
#include <linux/mm.h>
#include <linux/in.h>
#include <linux/init.h>
#include <net/p8022.h>
#include <net/arp.h>
#include <linux/rtnetlink.h>
#include <linux/brlock.h>
#include <linux/notifier.h>

#include <linux/if_vlan.h>
#include "vlan.h"
#include "vlanproc.h"

/* Global VLAN variables */

/* Our listing of VLAN group(s) */
struct vlan_group *p802_1Q_vlan_list;

static char vlan_fullname[] = "802.1Q VLAN Support";
static unsigned int vlan_version = 1;
static unsigned int vlan_release = 6;
static char vlan_copyright[] = " Ben Greear <[e-mail]>";

static int vlan_device_event(struct notifier_block *, unsigned long, void *);

struct notifier_block vlan_notifier_block = {
	notifier_call: vlan_device_event,
};

/* These may be changed at run-time through IOCTLs */

/* Determines interface naming scheme. */
unsigned short vlan_name_type = VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD;

/* Counter for how many NON-VLAN protos we've received on a VLAN. */
unsigned long vlan_bad_proto_recvd = 0;

/* DO reorder the header by default */
unsigned short vlan_default_dev_flags = 1;

static struct packet_type vlan_packet_type = {
	type: __constant_htons(ETH_P_8021Q),
	dev:  NULL,
	func: vlan_skb_recv, /* VLAN receive method */
	data: (void *)(-1),  /* Set here '(void *)1' when this code can SHARE SKBs */
	next: NULL
};

/* End of global variables definitions. */

/*
 * Function vlan_proto_init (pro)
 *
 *    Initialize VLAN protocol layer, 
 *
 */
static int __init vlan_proto_init(void)
{
	int err;

	printk(VLAN_INF "%s v%u.%u %s\n",
	       vlan_fullname, vlan_version, vlan_release, vlan_copyright);

	/* proc file system initialization */
	err = vlan_proc_init();
	if (err < 0) {
		printk(KERN_ERR __FUNCTION__
		       "%s: can't create entry in proc filesystem!\n",
		       VLAN_NAME);
		return 1;
	}

	dev_add_pack(&vlan_packet_type);

	/* Register us to receive netdevice events */
	register_netdevice_notifier(&vlan_notifier_block);

	vlan_ioctl_hook = vlan_ioctl_handler;

	printk(VLAN_INF "%s Initialization complete.\n", VLAN_NAME);
	return 0;
}

/*
 * Cleanup of groups before exit
 */

static void vlan_group_cleanup(void)
{
	struct vlan_group *grp = NULL;
	struct vlan_group *nextgroup;

	for (grp = p802_1Q_vlan_list; (grp != NULL);) {
		nextgroup = grp->next;
		kfree(grp);
		grp = nextgroup;
	}
	p802_1Q_vlan_list = NULL;
}

/*
 *     Module 'remove' entry point.
 *     o delete /proc/net/router directory and static entries.
 */ 
static void __exit vlan_cleanup_module(void)
{
	/* Un-register us from receiving netdevice events */
	unregister_netdevice_notifier(&vlan_notifier_block);

	dev_remove_pack(&vlan_packet_type);
	vlan_proc_cleanup();
	vlan_group_cleanup();
	vlan_ioctl_hook = NULL;
}

module_init(vlan_proto_init);
module_exit(vlan_cleanup_module);

/**  Will search linearly for now, based on device index.  Could
 * hash, or directly link, this some day. --Ben
 * TODO:  Potential performance issue here.  Linear search where N is
 *        the number of 'real' devices used by VLANs.
 */
struct vlan_group* vlan_find_group(int real_dev_ifindex)
{
	struct vlan_group *grp = NULL;

	br_read_lock_bh(BR_NETPROTO_LOCK);
	for (grp = p802_1Q_vlan_list;
	     ((grp != NULL) && (grp->real_dev_ifindex != real_dev_ifindex));
	     grp = grp->next) {
		/* nothing */ ;
	}
	br_read_unlock_bh(BR_NETPROTO_LOCK);

	return grp;
}

/*  Find the protocol handler.  Assumes VID < 0xFFF.
 */
struct net_device *find_802_1Q_vlan_dev(struct net_device *real_dev,
                                        unsigned short VID)
{
	struct vlan_group *grp = vlan_find_group(real_dev->ifindex);

	if (grp)
                return grp->vlan_devices[VID];

	return NULL;
}

/** This method will explicitly do a dev_put on the device if do_dev_put
 * is TRUE.  This gets around a difficulty with reference counting, and
 * the unregister-by-name (below).  If do_locks is true, it will grab
 * a lock before un-registering.  If do_locks is false, it is assumed that
 * the lock has already been grabbed externally...  --Ben
 */
int unregister_802_1Q_vlan_dev(int real_dev_ifindex, unsigned short vlan_id,
			       int do_dev_put, int do_locks)
{
	struct net_device *dev = NULL;
	struct vlan_group *grp;

#ifdef VLAN_DEBUG
	printk(VLAN_DBG __FUNCTION__ ": VID: %i\n", vlan_id);
#endif

	/* sanity check */
	if ((vlan_id >= 0xFFF) || (vlan_id <= 0))
		return -EINVAL;

	grp = vlan_find_group(real_dev_ifindex);
	if (grp) {
		dev = grp->vlan_devices[vlan_id];
		if (dev) {
			/* Remove proc entry */
			vlan_proc_rem_dev(dev);

			/* Take it out of our own structures */
			grp->vlan_devices[vlan_id] = NULL;

			/* Take it out of the global list of devices.
			 *  NOTE:  This deletes dev, don't access it again!!
			 */

			if (do_dev_put)
				dev_put(dev);

			/* TODO:  Please review this code. */
			if (do_locks) {
				rtnl_lock();
				unregister_netdevice(dev);
				rtnl_unlock();
			} else {
				unregister_netdevice(dev);
			}

			MOD_DEC_USE_COUNT;
		}
	}
        
        return 0;
}

int unregister_802_1Q_vlan_device(const char *vlan_IF_name)
{
	struct net_device *dev = NULL;

#ifdef VLAN_DEBUG
	printk(VLAN_DBG __FUNCTION__ ": unregister VLAN by name, name -:%s:-\n",
	       vlan_IF_name);
#endif

	dev = dev_get_by_name(vlan_IF_name);
	if (dev) {
		if (dev->priv_flags & IFF_802_1Q_VLAN) {
			return unregister_802_1Q_vlan_dev(
				VLAN_DEV_INFO(dev)->real_dev->ifindex,
				(unsigned short)(VLAN_DEV_INFO(dev)->vlan_id),
				1 /* do dev_put */, 1 /* do locking */);
		} else {
			printk(VLAN_ERR __FUNCTION__
			       ": ERROR:	Tried to remove a non-vlan device "
			       "with VLAN code, name: %s  priv_flags: %hX\n",
			       dev->name, dev->priv_flags);
			dev_put(dev);
			return -EPERM;
		}
	} else {
#ifdef VLAN_DEBUG
		printk(VLAN_DBG __FUNCTION__ ": WARNING: Could not find dev.\n");
#endif
		return -EINVAL;
	}
}

/*  Attach a VLAN device to a mac address (ie Ethernet Card).
 *  Returns the device that was created, or NULL if there was
 *  an error of some kind.
 */
struct net_device *register_802_1Q_vlan_device(const char* eth_IF_name,
					       unsigned short VLAN_ID)
{
	struct vlan_group *grp;
	struct net_device *new_dev;
	struct net_device *real_dev; /* the ethernet device */
	int malloc_size = 0;

#ifdef VLAN_DEBUG
	printk(VLAN_DBG __FUNCTION__ ": if_name -:%s:-	vid: %i\n",
	       eth_IF_name, VLAN_ID);
#endif

	if (VLAN_ID >= 0xfff)
		goto out_ret_null;

	/* find the device relating to eth_IF_name. */
	real_dev = dev_get_by_name(eth_IF_name);
	if (!real_dev)
		goto out_ret_null;

	/* TODO:  Make sure this device can really handle having a VLAN attached
	 * to it...
	 */
	if (find_802_1Q_vlan_dev(real_dev, VLAN_ID)) {
		/* was already registered. */
		printk(VLAN_DBG __FUNCTION__ ": ALREADY had VLAN registered\n");
		dev_put(real_dev);
		return NULL;
	}

	malloc_size = (sizeof(struct net_device));
	new_dev = (struct net_device *) kmalloc(malloc_size, GFP_KERNEL);
	VLAN_MEM_DBG("net_device malloc, addr: %p  size: %i\n",
		     new_dev, malloc_size);

	if (new_dev == NULL)
		goto out_put_dev;

	memset(new_dev, 0, malloc_size);

	/* set us up to not use a Qdisc, as the underlying Hardware device
	 * can do all the queueing we could want.
	 */
	/* new_dev->qdisc_sleeping = &noqueue_qdisc;   Not needed it seems. */
	new_dev->tx_queue_len = 0; /* This should effectively give us no queue. */

	/* Gotta set up the fields for the device. */
#ifdef VLAN_DEBUG
	printk(VLAN_DBG "About to allocate name, vlan_name_type: %i\n",
	       vlan_name_type);
#endif
	switch (vlan_name_type) {
	case VLAN_NAME_TYPE_RAW_PLUS_VID:
		/* name will look like:	 eth1.0005 */
		sprintf(new_dev->name, "%s.%.4i", real_dev->name, VLAN_ID);
		break;