vlan.c

linux 下对8021q协议的配置和实现的增强

/*
 * 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]>;
 *		Add HW acceleration hooks - David S. Miller <[e-mail]>;
 *		Correct all the locking - David S. Miller <[e-mail]>;
 *		Use hash table for VLAN groups - David S. Miller <[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/capability.h>
#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/notifier.h>

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

#define DRV_VERSION "1.8"

/* Global VLAN variables */

/* Our listing of VLAN group(s) */
static struct hlist_head vlan_group_hash[VLAN_GRP_HASH_SIZE];
#define vlan_grp_hashfn(IDX)	((((IDX) >> VLAN_GRP_HASH_SHIFT) ^ (IDX)) & VLAN_GRP_HASH_MASK)

static char vlan_fullname[] = "802.1Q VLAN Support";
static char vlan_version[] = DRV_VERSION;
static char vlan_copyright[] = "Ben Greear <[e-mail]>";
static char vlan_buggyright[] = "David S. Miller <[e-mail]>";

static int vlan_device_event(struct notifier_block *, unsigned long, void *);
static int vlan_ioctl_handler(void __user *);
static int unregister_vlan_dev(struct net_device *, unsigned short );

static 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;

static struct packet_type vlan_packet_type = {
	.type = __constant_htons(ETH_P_8021Q),
	.func = vlan_skb_recv, /* VLAN receive method */
};

/* 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%s %s\n",
	       vlan_fullname, vlan_version, vlan_copyright);
	printk(VLAN_INF "All bugs added by %s\n",
	       vlan_buggyright);

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

	dev_add_pack(&vlan_packet_type);

	/* Register us to receive netdevice events */
	err = register_netdevice_notifier(&vlan_notifier_block);
	if (err < 0) {
		dev_remove_pack(&vlan_packet_type);
		vlan_proc_cleanup();
		return err;
	}

	vlan_ioctl_set(vlan_ioctl_handler);

	return 0;
}

/* Cleanup all vlan devices 
 * Note: devices that have been registered that but not
 * brought up will exist but have no module ref count.
 */
static void __exit vlan_cleanup_devices(void)
{
	struct net_device *dev, *nxt;

	rtnl_lock();
	for (dev = dev_base; dev; dev = nxt) {
		nxt = dev->next;
		if (dev->priv_flags & IFF_802_1Q_VLAN) {
			unregister_vlan_dev(VLAN_DEV_INFO(dev)->real_dev,
					    VLAN_DEV_INFO(dev)->vlan_id);

			unregister_netdevice(dev);
		}
	}
	rtnl_unlock();
}

/*
 *     Module 'remove' entry point.
 *     o delete /proc/net/router directory and static entries.
 */ 
static void __exit vlan_cleanup_module(void)
{
	int i;

	vlan_ioctl_set(NULL);

	/* Un-register us from receiving netdevice events */
	unregister_netdevice_notifier(&vlan_notifier_block);

	dev_remove_pack(&vlan_packet_type);
	vlan_cleanup_devices();

	/* This table must be empty if there are no module
	 * references left.
	 */
	for (i = 0; i < VLAN_GRP_HASH_SIZE; i++) {
		BUG_ON(!hlist_empty(&vlan_group_hash[i]));
	}
	vlan_proc_cleanup();

	synchronize_net();
}

module_init(vlan_proto_init);
module_exit(vlan_cleanup_module);

/* Must be invoked with RCU read lock (no preempt) */
static struct vlan_group *__vlan_find_group(int real_dev_ifindex)
{
	struct vlan_group *grp;
	struct hlist_node *n;
	int hash = vlan_grp_hashfn(real_dev_ifindex);

	hlist_for_each_entry_rcu(grp, n, &vlan_group_hash[hash], hlist) {
		if (grp->real_dev_ifindex == real_dev_ifindex)
			return grp;
	}

	return NULL;
}

/*  Find the protocol handler.  Assumes VID < VLAN_VID_MASK.
 *
 * Must be invoked with RCU read lock (no preempt)
 */
struct net_device *__find_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;
}

static void vlan_rcu_free(struct rcu_head *rcu)
{
	kfree(container_of(rcu, struct vlan_group, rcu));
}


/* This returns 0 if everything went fine.
 * It will return 1 if the group was killed as a result.
 * A negative return indicates failure.
 *
 * The RTNL lock must be held.
 */
static int unregister_vlan_dev(struct net_device *real_dev,
			       unsigned short vlan_id)
{
	struct net_device *dev = NULL;
	int real_dev_ifindex = real_dev->ifindex;
	struct vlan_group *grp;
	int i, ret;

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

	/* sanity check */
	if (vlan_id >= VLAN_VID_MASK)
		return -EINVAL;

	ASSERT_RTNL();
	grp = __vlan_find_group(real_dev_ifindex);

	ret = 0;

	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, but be sure to
			 * interlock with HW accelerating devices or SW vlan
			 * input packet processing.
			 */
			if (real_dev->features &
			    (NETIF_F_HW_VLAN_RX | NETIF_F_HW_VLAN_FILTER)) {
				real_dev->vlan_rx_kill_vid(real_dev, vlan_id);
			}

			grp->vlan_devices[vlan_id] = NULL;
			synchronize_net();


			/* Caller unregisters (and if necessary, puts)
			 * VLAN device, but we get rid of the reference to
			 * real_dev here.
			 */
			dev_put(real_dev);

			/* If the group is now empty, kill off the
			 * group.
			 */
			for (i = 0; i < VLAN_VID_MASK; i++)
				if (grp->vlan_devices[i])
					break;

			if (i == VLAN_VID_MASK) {
				if (real_dev->features & NETIF_F_HW_VLAN_RX)
					real_dev->vlan_rx_register(real_dev, NULL);

				hlist_del_rcu(&grp->hlist);

				/* Free the group, after all cpu's are done. */
				call_rcu(&grp->rcu, vlan_rcu_free);

				grp = NULL;
				ret = 1;
			}
		}
	}

        return ret;
}

static int unregister_vlan_device(const char *vlan_IF_name)
{
	struct net_device *dev = NULL;
	int ret;


	dev = dev_get_by_name(vlan_IF_name);
	ret = -EINVAL;
	if (dev) {
		if (dev->priv_flags & IFF_802_1Q_VLAN) {
			rtnl_lock();

			ret = unregister_vlan_dev(VLAN_DEV_INFO(dev)->real_dev,
						  VLAN_DEV_INFO(dev)->vlan_id);

			dev_put(dev);
			unregister_netdevice(dev);

			rtnl_unlock();

			if (ret == 1)
				ret = 0;
		} else {
			printk(VLAN_ERR 
			       "%s: ERROR:	Tried to remove a non-vlan device "
			       "with VLAN code, name: %s  priv_flags: %hX\n",
			       __FUNCTION__, dev->name, dev->priv_flags);
			dev_put(dev);
			ret = -EPERM;
		}
	} else {
#ifdef VLAN_DEBUG
		printk(VLAN_DBG "%s: WARNING: Could not find dev.\n", __FUNCTION__);
#endif
		ret = -EINVAL;
	}

	return ret;
}

static void vlan_setup(struct net_device *new_dev)
{
	SET_MODULE_OWNER(new_dev);
	    
	/* new_dev->ifindex = 0;  it will be set when added to
	 * the global list.
	 * iflink is set as well.
	 */
	new_dev->get_stats = vlan_dev_get_stats;

	/* Make this thing known as a VLAN device */
	new_dev->priv_flags |= IFF_802_1Q_VLAN;
				
	/* Set us up to have no queue, as the underlying Hardware device
	 * can do all the queueing we could want.
	 */
	new_dev->tx_queue_len = 0;

	/* set up method calls */
	new_dev->change_mtu = vlan_dev_change_mtu;
	new_dev->open = vlan_dev_open;
	new_dev->stop = vlan_dev_stop;
	new_dev->set_mac_address = vlan_dev_set_mac_address;
	new_dev->set_multicast_list = vlan_dev_set_multicast_list;
	new_dev->destructor = free_netdev;
	new_dev->do_ioctl = vlan_dev_ioctl;
}

static void vlan_transfer_operstate(const struct net_device *dev, struct net_device *vlandev)
{
	/* Have to respect userspace enforced dormant state
	 * of real device, also must allow supplicant running
	 * on VLAN device
	 */
	if (dev->operstate == IF_OPER_DORMANT)
		netif_dormant_on(vlandev);
	else
		netif_dormant_off(vlandev);

	if (netif_carrier_ok(dev)) {
		if (!netif_carrier_ok(vlandev))
			netif_carrier_on(vlandev);
	} else {
		if (netif_carrier_ok(vlandev))
			netif_carrier_off(vlandev);
	}
}

/*
 * vlan network devices have devices nesting below it, and are a special
 * "super class" of normal network devices; split their locks off into a
 * separate class since they always nest.
 */
static struct lock_class_key vlan_netdev_xmit_lock_key;


/*  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.
 */
static struct net_device *register_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 */
	char name[IFNAMSIZ];

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

	if (VLAN_ID >= VLAN_VID_MASK)
		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;

	if (real_dev->features & NETIF_F_VLAN_CHALLENGED) {
		printk(VLAN_DBG "%s: VLANs not supported on %s.\n",
			__FUNCTION__, real_dev->name);
		goto out_put_dev;
	}

	if ((real_dev->features & NETIF_F_HW_VLAN_RX) &&
	    (real_dev->vlan_rx_register == NULL ||
	     real_dev->vlan_rx_kill_vid == NULL)) {