vlan.c

linux 内核源代码

/*
 * 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 <net/net_namespace.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(struct net *net, 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)
		goto err1;

	err = vlan_netlink_init();
	if (err < 0)
		goto err2;

	vlan_ioctl_set(vlan_ioctl_handler);
	return 0;

err2:
	unregister_netdevice_notifier(&vlan_notifier_block);
err1:
	vlan_proc_cleanup();
	dev_remove_pack(&vlan_packet_type);
	return err;
}

/*
 *     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);
	vlan_netlink_fini();

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

	dev_remove_pack(&vlan_packet_type);

	/* 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 vlan_group_get_device(grp, VID);

	return NULL;
}

static void vlan_group_free(struct vlan_group *grp)
{
	int i;

	for (i=0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++)
		kfree(grp->vlan_devices_arrays[i]);
	kfree(grp);
}

static struct vlan_group *vlan_group_alloc(int ifindex)
{
	struct vlan_group *grp;
	unsigned int size;
	unsigned int i;

	grp = kzalloc(sizeof(struct vlan_group), GFP_KERNEL);
	if (!grp)
		return NULL;

	size = sizeof(struct net_device *) * VLAN_GROUP_ARRAY_PART_LEN;

	for (i = 0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++) {
		grp->vlan_devices_arrays[i] = kzalloc(size, GFP_KERNEL);
		if (!grp->vlan_devices_arrays[i])
			goto err;
	}

	grp->real_dev_ifindex = ifindex;
	hlist_add_head_rcu(&grp->hlist,
			   &vlan_group_hash[vlan_grp_hashfn(ifindex)]);
	return grp;

err:
	vlan_group_free(grp);
	return NULL;
}

static void vlan_rcu_free(struct rcu_head *rcu)
{
	vlan_group_free(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 = vlan_group_get_device(grp, 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_FILTER)
				real_dev->vlan_rx_kill_vid(real_dev, vlan_id);

			vlan_group_set_device(grp, 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 (vlan_group_get_device(grp, 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;
}

int unregister_vlan_device(struct net_device *dev)
{
	int ret;

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

	if (ret == 1)
		ret = 0;
	return ret;
}

/*
 * 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;

static const struct header_ops vlan_header_ops = {
	.create	 = vlan_dev_hard_header,
	.rebuild = vlan_dev_rebuild_header,
	.parse	 = eth_header_parse,
};

static int vlan_dev_init(struct net_device *dev)
{
	struct net_device *real_dev = VLAN_DEV_INFO(dev)->real_dev;
	int subclass = 0;

	/* IFF_BROADCAST|IFF_MULTICAST; ??? */
	dev->flags  = real_dev->flags & ~IFF_UP;
	dev->iflink = real_dev->ifindex;
	dev->state  = (real_dev->state & ((1<<__LINK_STATE_NOCARRIER) |
					  (1<<__LINK_STATE_DORMANT))) |
		      (1<<__LINK_STATE_PRESENT);

	/* ipv6 shared card related stuff */
	dev->dev_id = real_dev->dev_id;

	if (is_zero_ether_addr(dev->dev_addr))
		memcpy(dev->dev_addr, real_dev->dev_addr, dev->addr_len);
	if (is_zero_ether_addr(dev->broadcast))
		memcpy(dev->broadcast, real_dev->broadcast, dev->addr_len);

	if (real_dev->features & NETIF_F_HW_VLAN_TX) {
		dev->header_ops      = real_dev->header_ops;
		dev->hard_header_len = real_dev->hard_header_len;
		dev->hard_start_xmit = vlan_dev_hwaccel_hard_start_xmit;
	} else {
		dev->header_ops      = &vlan_header_ops;
		dev->hard_header_len = real_dev->hard_header_len + VLAN_HLEN;
		dev->hard_start_xmit = vlan_dev_hard_start_xmit;
	}

	if (real_dev->priv_flags & IFF_802_1Q_VLAN)
		subclass = 1;

	lockdep_set_class_and_subclass(&dev->_xmit_lock,
				&vlan_netdev_xmit_lock_key, subclass);
	return 0;
}

void vlan_setup(struct net_device *new_dev)
{
	ether_setup(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->init = vlan_dev_init;
	new_dev->open = vlan_dev_open;
	new_dev->stop = vlan_dev_stop;
	new_dev->set_mac_address = vlan_set_mac_address;
	new_dev->set_multicast_list = vlan_dev_set_multicast_list;
	new_dev->change_rx_flags = vlan_change_rx_flags;
	new_dev->destructor = free_netdev;
	new_dev->do_ioctl = vlan_dev_ioctl;

	memset(new_dev->broadcast, 0, ETH_ALEN);
}

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);
	}
}

int vlan_check_real_dev(struct net_device *real_dev, unsigned short vlan_id)
{
	if (real_dev->features & NETIF_F_VLAN_CHALLENGED) {
		printk(VLAN_DBG "%s: VLANs not supported on %s.\n",
			__FUNCTION__, real_dev->name);
		return -EOPNOTSUPP;
	}

	if ((real_dev->features & NETIF_F_HW_VLAN_RX) &&
	    !real_dev->vlan_rx_register) {
		printk(VLAN_DBG "%s: Device %s has buggy VLAN hw accel.\n",
			__FUNCTION__, real_dev->name);
		return -EOPNOTSUPP;
	}

	if ((real_dev->features & NETIF_F_HW_VLAN_FILTER) &&
	    (!real_dev->vlan_rx_add_vid || !real_dev->vlan_rx_kill_vid)) {
		printk(VLAN_DBG "%s: Device %s has buggy VLAN hw accel.\n",
			__FUNCTION__, real_dev->name);