net/core/dev_mcast.c

   1 /*
   2  *      Linux NET3:     Multicast List maintenance.
   3  *
   4  *      Authors:
   5  *              Tim Kordas <tjk@nostromo.eeap.cwru.edu>
   6  *              Richard Underwood <richard@wuzz.demon.co.uk>
   7  *
   8  *      Stir fried together from the IP multicast and CAP patches above
   9  *              Alan Cox <Alan.Cox@linux.org>
  10  *
  11  *      Fixes:
  12  *              Alan Cox        :       Update the device on a real delete
  13  *                                      rather than any time but...
  14  *              Alan Cox        :       IFF_ALLMULTI support.
  15  *              Alan Cox        :       New format set_multicast_list() calls.
  16  *              Gleb Natapov    :       Remove dev_mc_lock.
  17  *
  18  *      This program is free software; you can redistribute it and/or
  19  *      modify it under the terms of the GNU General Public License
  20  *      as published by the Free Software Foundation; either version
  21  *      2 of the License, or (at your option) any later version.
  22  */
  23
  24 #include <linux/module.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/system.h>
  27 #include <linux/bitops.h>
  28 #include <linux/types.h>
  29 #include <linux/kernel.h>
  30 #include <linux/string.h>
  31 #include <linux/mm.h>
  32 #include <linux/socket.h>
  33 #include <linux/sockios.h>
  34 #include <linux/in.h>
  35 #include <linux/errno.h>
  36 #include <linux/interrupt.h>
  37 #include <linux/if_ether.h>
  38 #include <linux/inet.h>
  39 #include <linux/netdevice.h>
  40 #include <linux/etherdevice.h>
  41 #include <linux/proc_fs.h>
  42 #include <linux/seq_file.h>
  43 #include <linux/init.h>
  44 #include <net/ip.h>
  45 #include <net/route.h>
  46 #include <linux/skbuff.h>
  47 #include <net/sock.h>
  48 #include <net/arp.h>
  49
  50
  51 /*
  52  *      Device multicast list maintenance.
  53  *
  54  *      This is used both by IP and by the user level maintenance functions.
  55  *      Unlike BSD we maintain a usage count on a given multicast address so
  56  *      that a casual user application can add/delete multicasts used by
  57  *      protocols without doing damage to the protocols when it deletes the
  58  *      entries. It also helps IP as it tracks overlapping maps.
  59  *
  60  *      Device mc lists are changed by bh at least if IPv6 is enabled,
  61  *      so that it must be bh protected.
  62  *
  63  *      We block accesses to device mc filters with netif_tx_lock.
  64  */
  65
  66 /*
  67  *      Delete a device level multicast
  68  */
  69
  70 int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
  71 {
  72         int err;
  73
  74         netif_tx_lock_bh(dev);
  75         err = __dev_addr_delete(&dev->mc_list, addr, alen, glbl);
  76         if (!err) {
  77                 dev->mc_count--;
  78
  79                 /*
  80                  *      We have altered the list, so the card
  81                  *      loaded filter is now wrong. Fix it
  82                  */
  83
  84                 __dev_set_rx_mode(dev);
  85         }
  86         netif_tx_unlock_bh(dev);
  87         return err;
  88 }
  89
  90 /*
  91  *      Add a device level multicast
  92  */
  93
  94 int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
  95 {
  96         int err;
  97
  98         netif_tx_lock_bh(dev);
  99         err = __dev_addr_add(&dev->mc_list, addr, alen, glbl);
 100         if (!err) {
 101                 dev->mc_count++;
 102                 __dev_set_rx_mode(dev);
 103         }
 104         netif_tx_unlock_bh(dev);
 105         return err;
 106 }
 107
 108 /*
 109  *      Discard multicast list when a device is downed
 110  */
 111
 112 void dev_mc_discard(struct net_device *dev)
 113 {
 114         netif_tx_lock_bh(dev);
 115         __dev_addr_discard(&dev->mc_list);
 116         dev->mc_count = 0;
 117         netif_tx_unlock_bh(dev);
 118 }
 119
 120 #ifdef CONFIG_PROC_FS
 121 static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
 122 {
 123         struct net_device *dev;
 124         loff_t off = 0;
 125
 126         read_lock(&dev_base_lock);
 127         for_each_netdev(dev) {
 128                 if (off++ == *pos)
 129                         return dev;
 130         }
 131         return NULL;
 132 }
 133
 134 static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 135 {
 136         ++*pos;
 137         return next_net_device((struct net_device *)v);
 138 }
 139
 140 static void dev_mc_seq_stop(struct seq_file *seq, void *v)
 141 {
 142         read_unlock(&dev_base_lock);
 143 }
 144
 145
 146 static int dev_mc_seq_show(struct seq_file *seq, void *v)
 147 {
 148         struct dev_addr_list *m;
 149         struct net_device *dev = v;
 150
 151         netif_tx_lock_bh(dev);
 152         for (m = dev->mc_list; m; m = m->next) {
 153                 int i;
 154
 155                 seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
 156                            dev->name, m->dmi_users, m->dmi_gusers);
 157
 158                 for (i = 0; i < m->dmi_addrlen; i++)
 159                         seq_printf(seq, "%02x", m->dmi_addr[i]);
 160
 161                 seq_putc(seq, '\n');
 162         }
 163         netif_tx_unlock_bh(dev);
 164         return 0;
 165 }
 166
 167 static const struct seq_operations dev_mc_seq_ops = {
 168         .start = dev_mc_seq_start,
 169         .next  = dev_mc_seq_next,
 170         .stop  = dev_mc_seq_stop,
 171         .show  = dev_mc_seq_show,
 172 };
 173
 174 static int dev_mc_seq_open(struct inode *inode, struct file *file)
 175 {
 176         return seq_open(file, &dev_mc_seq_ops);
 177 }
 178
 179 static const struct file_operations dev_mc_seq_fops = {
 180         .owner   = THIS_MODULE,
 181         .open    = dev_mc_seq_open,
 182         .read    = seq_read,
 183         .llseek  = seq_lseek,
 184         .release = seq_release,
 185 };
 186
 187 #endif
 188
 189 void __init dev_mcast_init(void)
 190 {
 191         proc_net_fops_create("dev_mcast", 0, &dev_mc_seq_fops);
 192 }
 193
 194 EXPORT_SYMBOL(dev_mc_add);
 195 EXPORT_SYMBOL(dev_mc_delete);