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/net_namespace.h>
  45 #include <net/ip.h>
  46 #include <net/route.h>
  47 #include <linux/skbuff.h>
  48 #include <net/sock.h>
  49 #include <net/arp.h>
  50
  51
  52 /*
  53  *      Device multicast list maintenance.
  54  *
  55  *      This is used both by IP and by the user level maintenance functions.
  56  *      Unlike BSD we maintain a usage count on a given multicast address so
  57  *      that a casual user application can add/delete multicasts used by
  58  *      protocols without doing damage to the protocols when it deletes the
  59  *      entries. It also helps IP as it tracks overlapping maps.
  60  *
  61  *      Device mc lists are changed by bh at least if IPv6 is enabled,
  62  *      so that it must be bh protected.
  63  *
  64  *      We block accesses to device mc filters with netif_tx_lock.
  65  */
  66
  67 /*
  68  *      Delete a device level multicast
  69  */
  70
  71 int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
  72 {
  73         int err;
  74
  75         netif_tx_lock_bh(dev);
  76         err = __dev_addr_delete(&dev->mc_list, &dev->mc_count,
  77                                 addr, alen, glbl);
  78         if (!err) {
  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, &dev->mc_count, addr, alen, glbl);
 100         if (!err)
 101                 __dev_set_rx_mode(dev);
 102         netif_tx_unlock_bh(dev);
 103         return err;
 104 }
 105
 106 /**
 107  *      dev_mc_sync     - Synchronize device's multicast list to another device
 108  *      @to: destination device
 109  *      @from: source device
 110  *
 111  *      Add newly added addresses to the destination device and release
 112  *      addresses that have no users left. The source device must be
 113  *      locked by netif_tx_lock_bh.
 114  *
 115  *      This function is intended to be called from the dev->set_multicast_list
 116  *      or dev->set_rx_mode function of layered software devices.
 117  */
 118 int dev_mc_sync(struct net_device *to, struct net_device *from)
 119 {
 120         int err = 0;
 121
 122         netif_tx_lock_bh(to);
 123         err = __dev_addr_sync(&to->mc_list, &to->mc_count,
 124                               &from->mc_list, &from->mc_count);
 125         if (!err)
 126                 __dev_set_rx_mode(to);
 127         netif_tx_unlock_bh(to);
 128
 129         return err;
 130 }
 131 EXPORT_SYMBOL(dev_mc_sync);
 132
 133
 134 /**
 135  *      dev_mc_unsync   - Remove synchronized addresses from the destination
 136  *                        device
 137  *      @to: destination device
 138  *      @from: source device
 139  *
 140  *      Remove all addresses that were added to the destination device by
 141  *      dev_mc_sync(). This function is intended to be called from the
 142  *      dev->stop function of layered software devices.
 143  */
 144 void dev_mc_unsync(struct net_device *to, struct net_device *from)
 145 {
 146         netif_tx_lock_bh(from);
 147         netif_tx_lock_bh(to);
 148
 149         __dev_addr_unsync(&to->mc_list, &to->mc_count,
 150                           &from->mc_list, &from->mc_count);
 151         __dev_set_rx_mode(to);
 152
 153         netif_tx_unlock_bh(to);
 154         netif_tx_unlock_bh(from);
 155 }
 156 EXPORT_SYMBOL(dev_mc_unsync);
 157
 158 #ifdef CONFIG_PROC_FS
 159 static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
 160         __acquires(dev_base_lock)
 161 {
 162         struct net *net = seq_file_net(seq);
 163         struct net_device *dev;
 164         loff_t off = 0;
 165
 166         read_lock(&dev_base_lock);
 167         for_each_netdev(net, dev) {
 168                 if (off++ == *pos)
 169                         return dev;
 170         }
 171         return NULL;
 172 }
 173
 174 static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 175 {
 176         ++*pos;
 177         return next_net_device((struct net_device *)v);
 178 }
 179
 180 static void dev_mc_seq_stop(struct seq_file *seq, void *v)
 181         __releases(dev_base_lock)
 182 {
 183         read_unlock(&dev_base_lock);
 184 }
 185
 186
 187 static int dev_mc_seq_show(struct seq_file *seq, void *v)
 188 {
 189         struct dev_addr_list *m;
 190         struct net_device *dev = v;
 191
 192         netif_tx_lock_bh(dev);
 193         for (m = dev->mc_list; m; m = m->next) {
 194                 int i;
 195
 196                 seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
 197                            dev->name, m->dmi_users, m->dmi_gusers);
 198
 199                 for (i = 0; i < m->dmi_addrlen; i++)
 200                         seq_printf(seq, "%02x", m->dmi_addr[i]);
 201
 202                 seq_putc(seq, '\n');
 203         }
 204         netif_tx_unlock_bh(dev);
 205         return 0;
 206 }
 207
 208 static const struct seq_operations dev_mc_seq_ops = {
 209         .start = dev_mc_seq_start,
 210         .next  = dev_mc_seq_next,
 211         .stop  = dev_mc_seq_stop,
 212         .show  = dev_mc_seq_show,
 213 };
 214
 215 static int dev_mc_seq_open(struct inode *inode, struct file *file)
 216 {
 217         return seq_open_net(inode, file, &dev_mc_seq_ops,
 218                             sizeof(struct seq_net_private));
 219 }
 220
 221 static const struct file_operations dev_mc_seq_fops = {
 222         .owner   = THIS_MODULE,
 223         .open    = dev_mc_seq_open,
 224         .read    = seq_read,
 225         .llseek  = seq_lseek,
 226         .release = seq_release_net,
 227 };
 228
 229 #endif
 230
 231 static int __net_init dev_mc_net_init(struct net *net)
 232 {
 233         if (!proc_net_fops_create(net, "dev_mcast", 0, &dev_mc_seq_fops))
 234                 return -ENOMEM;
 235         return 0;
 236 }
 237
 238 static void __net_exit dev_mc_net_exit(struct net *net)
 239 {
 240         proc_net_remove(net, "dev_mcast");
 241 }
 242
 243 static struct pernet_operations __net_initdata dev_mc_net_ops = {
 244         .init = dev_mc_net_init,
 245         .exit = dev_mc_net_exit,
 246 };
 247
 248 void __init dev_mcast_init(void)
 249 {
 250         register_pernet_subsys(&dev_mc_net_ops);
 251 }
 252
 253 EXPORT_SYMBOL(dev_mc_add);
 254 EXPORT_SYMBOL(dev_mc_delete);