/*
 *      Linux NET3:     Multicast List maintenance.
 *
 *      Authors:
 *              Tim Kordas <tjk@nostromo.eeap.cwru.edu>
 *              Richard Underwood <richard@wuzz.demon.co.uk>
 *
 *      Stir fried together from the IP multicast and CAP patches above
 *              Alan Cox <Alan.Cox@linux.org>
 *
 *      Fixes:
 *              Alan Cox        :       Update the device on a real delete
 *                                      rather than any time but...
 *              Alan Cox        :       IFF_ALLMULTI support.
 *              Alan Cox        :       New format set_multicast_list() calls.
 *              Gleb Natapov    :       Remove dev_mc_lock.
 *
 *      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 <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/arp.h>


/*
 *      Device multicast list maintenance.
 *
 *      This is used both by IP and by the user level maintenance functions.
 *      Unlike BSD we maintain a usage count on a given multicast address so
 *      that a casual user application can add/delete multicasts used by
 *      protocols without doing damage to the protocols when it deletes the
 *      entries. It also helps IP as it tracks overlapping maps.
 *
 *      Device mc lists are changed by bh at least if IPv6 is enabled,
 *      so that it must be bh protected.
 *
 *      We block accesses to device mc filters with netif_tx_lock.
 */

/*
 *      Delete a device level multicast
 */

int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
{
        int err;

        netif_tx_lock_bh(dev);
        err = __dev_addr_delete(&dev->mc_list, &dev->mc_count,
                                addr, alen, glbl);
        if (!err) {
                /*
                 *      We have altered the list, so the card
                 *      loaded filter is now wrong. Fix it
                 */

                __dev_set_rx_mode(dev);
        }
        netif_tx_unlock_bh(dev);
        return err;
}

/*
 *      Add a device level multicast
 */

int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
{
        int err;

        netif_tx_lock_bh(dev);
        err = __dev_addr_add(&dev->mc_list, &dev->mc_count, addr, alen, glbl);
        if (!err)
                __dev_set_rx_mode(dev);
        netif_tx_unlock_bh(dev);
        return err;
}

/**
 *      dev_mc_sync     - Synchronize device's multicast list to another device
 *      @to: destination device
 *      @from: source device
 *
 *      Add newly added addresses to the destination device and release
 *      addresses that have no users left. The source device must be
 *      locked by netif_tx_lock_bh.
 *
 *      This function is intended to be called from the dev->set_multicast_list
 *      function of layered software devices.
 */
int dev_mc_sync(struct net_device *to, struct net_device *from)
{
        struct dev_addr_list *da, *next;
        int err = 0;

        netif_tx_lock_bh(to);
        da = from->mc_list;
        while (da != NULL) {
                next = da->next;
                if (!da->da_synced) {
                        err = __dev_addr_add(&to->mc_list, &to->mc_count,
                                             da->da_addr, da->da_addrlen, 0);
                        if (err < 0)
                                break;
                        da->da_synced = 1;
                        da->da_users++;
                } else if (da->da_users == 1) {
                        __dev_addr_delete(&to->mc_list, &to->mc_count,
                                          da->da_addr, da->da_addrlen, 0);
                        __dev_addr_delete(&from->mc_list, &from->mc_count,
                                          da->da_addr, da->da_addrlen, 0);
                }
                da = next;
        }
        if (!err)
                __dev_set_rx_mode(to);
        netif_tx_unlock_bh(to);

        return err;
}
EXPORT_SYMBOL(dev_mc_sync);


/**
 *      dev_mc_unsync   - Remove synchronized addresses from the destination
 *                        device
 *      @to: destination device
 *      @from: source device
 *
 *      Remove all addresses that were added to the destination device by
 *      dev_mc_sync(). This function is intended to be called from the
 *      dev->stop function of layered software devices.
 */
void dev_mc_unsync(struct net_device *to, struct net_device *from)
{
        struct dev_addr_list *da, *next;

        netif_tx_lock_bh(from);
        netif_tx_lock_bh(to);

        da = from->mc_list;
        while (da != NULL) {
                next = da->next;
                if (da->da_synced) {
                        __dev_addr_delete(&to->mc_list, &to->mc_count,
                                          da->da_addr, da->da_addrlen, 0);
                        da->da_synced = 0;
                        __dev_addr_delete(&from->mc_list, &from->mc_count,
                                          da->da_addr, da->da_addrlen, 0);
                }
                da = next;
        }
        __dev_set_rx_mode(to);

        netif_tx_unlock_bh(to);
        netif_tx_unlock_bh(from);
}
EXPORT_SYMBOL(dev_mc_unsync);

#ifdef CONFIG_PROC_FS
static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
{
        struct net *net = seq->private;
        struct net_device *dev;
        loff_t off = 0;

        read_lock(&dev_base_lock);
        for_each_netdev(net, dev) {
                if (off++ == *pos)
                        return dev;
        }
        return NULL;
}

static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        ++*pos;
        return next_net_device((struct net_device *)v);
}

static void dev_mc_seq_stop(struct seq_file *seq, void *v)
{
        read_unlock(&dev_base_lock);
}


static int dev_mc_seq_show(struct seq_file *seq, void *v)
{
        struct dev_addr_list *m;
        struct net_device *dev = v;

        netif_tx_lock_bh(dev);
        for (m = dev->mc_list; m; m = m->next) {
                int i;

                seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
                           dev->name, m->dmi_users, m->dmi_gusers);

                for (i = 0; i < m->dmi_addrlen; i++)
                        seq_printf(seq, "%02x", m->dmi_addr[i]);

                seq_putc(seq, '\n');
        }
        netif_tx_unlock_bh(dev);
        return 0;
}

static const struct seq_operations dev_mc_seq_ops = {
        .start = dev_mc_seq_start,
        .next  = dev_mc_seq_next,
        .stop  = dev_mc_seq_stop,
        .show  = dev_mc_seq_show,
};

static int dev_mc_seq_open(struct inode *inode, struct file *file)
{
        struct seq_file *seq;
        int res;
        res = seq_open(file, &dev_mc_seq_ops);
        if (!res) {
                seq = file->private_data;
                seq->private = get_proc_net(inode);
                if (!seq->private) {
                        seq_release(inode, file);
                        res = -ENXIO;
                }
        }
        return res;
}

static int dev_mc_seq_release(struct inode *inode, struct file *file)
{
        struct seq_file *seq = file->private_data;
        struct net *net = seq->private;
        put_net(net);
        return seq_release(inode, file);
}

static const struct file_operations dev_mc_seq_fops = {
        .owner   = THIS_MODULE,
        .open    = dev_mc_seq_open,
        .read    = seq_read,
        .llseek  = seq_lseek,
        .release = dev_mc_seq_release,
};

#endif

static int __net_init dev_mc_net_init(struct net *net)
{
        if (!proc_net_fops_create(net, "dev_mcast", 0, &dev_mc_seq_fops))
                return -ENOMEM;
        return 0;
}

static void __net_exit dev_mc_net_exit(struct net *net)
{
        proc_net_remove(net, "dev_mcast");
}

static struct pernet_operations __net_initdata dev_mc_net_ops = {
        .init = dev_mc_net_init,
        .exit = dev_mc_net_exit,
};

void __init dev_mcast_init(void)
{
        register_pernet_subsys(&dev_mc_net_ops);
}

EXPORT_SYMBOL(dev_mc_add);
EXPORT_SYMBOL(dev_mc_delete);