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  *      function of layered software devices.
 117  */
 118 int dev_mc_sync(struct net_device *to, struct net_device *from)
 119 {
 120         struct dev_addr_list *da, *next;
 121         int err = 0;
 122
 123         netif_tx_lock_bh(to);
 124         da = from->mc_list;
 125         while (da != NULL) {
 126                 next = da->next;
 127                 if (!da->da_synced) {
 128                         err = __dev_addr_add(&to->mc_list, &to->mc_count,
 129                                              da->da_addr, da->da_addrlen, 0);
 130                         if (err < 0)
 131                                 break;
 132                         da->da_synced = 1;
 133                         da->da_users++;
 134                 } else if (da->da_users == 1) {
 135                         __dev_addr_delete(&to->mc_list, &to->mc_count,
 136                                           da->da_addr, da->da_addrlen, 0);
 137                         __dev_addr_delete(&from->mc_list, &from->mc_count,
 138                                           da->da_addr, da->da_addrlen, 0);
 139                 }
 140                 da = next;
 141         }
 142         if (!err)
 143                 __dev_set_rx_mode(to);
 144         netif_tx_unlock_bh(to);
 145
 146         return err;
 147 }
 148 EXPORT_SYMBOL(dev_mc_sync);
 149
 150
 151 /**
 152  *      dev_mc_unsync   - Remove synchronized addresses from the destination
 153  *                        device
 154  *      @to: destination device
 155  *      @from: source device
 156  *
 157  *      Remove all addresses that were added to the destination device by
 158  *      dev_mc_sync(). This function is intended to be called from the
 159  *      dev->stop function of layered software devices.
 160  */
 161 void dev_mc_unsync(struct net_device *to, struct net_device *from)
 162 {
 163         struct dev_addr_list *da, *next;
 164
 165         netif_tx_lock_bh(from);
 166         netif_tx_lock_bh(to);
 167
 168         da = from->mc_list;
 169         while (da != NULL) {
 170                 next = da->next;
 171                 if (!da->da_synced)
 172                         continue;
 173                 __dev_addr_delete(&to->mc_list, &to->mc_count,
 174                                   da->da_addr, da->da_addrlen, 0);
 175                 da->da_synced = 0;
 176                 __dev_addr_delete(&from->mc_list, &from->mc_count,
 177                                   da->da_addr, da->da_addrlen, 0);
 178                 da = next;
 179         }
 180         __dev_set_rx_mode(to);
 181
 182         netif_tx_unlock_bh(to);
 183         netif_tx_unlock_bh(from);
 184 }
 185 EXPORT_SYMBOL(dev_mc_unsync);
 186
 187 #ifdef CONFIG_PROC_FS
 188 static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
 189 {
 190         struct net *net = seq->private;
 191         struct net_device *dev;
 192         loff_t off = 0;
 193
 194         read_lock(&dev_base_lock);
 195         for_each_netdev(net, dev) {
 196                 if (off++ == *pos)
 197                         return dev;
 198         }
 199         return NULL;
 200 }
 201
 202 static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 203 {
 204         ++*pos;
 205         return next_net_device((struct net_device *)v);
 206 }
 207
 208 static void dev_mc_seq_stop(struct seq_file *seq, void *v)
 209 {
 210         read_unlock(&dev_base_lock);
 211 }
 212
 213
 214 static int dev_mc_seq_show(struct seq_file *seq, void *v)
 215 {
 216         struct dev_addr_list *m;
 217         struct net_device *dev = v;
 218
 219         netif_tx_lock_bh(dev);
 220         for (m = dev->mc_list; m; m = m->next) {
 221                 int i;
 222
 223                 seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
 224                            dev->name, m->dmi_users, m->dmi_gusers);
 225
 226                 for (i = 0; i < m->dmi_addrlen; i++)
 227                         seq_printf(seq, "%02x", m->dmi_addr[i]);
 228
 229                 seq_putc(seq, '\n');
 230         }
 231         netif_tx_unlock_bh(dev);
 232         return 0;
 233 }
 234
 235 static const struct seq_operations dev_mc_seq_ops = {
 236         .start = dev_mc_seq_start,
 237         .next  = dev_mc_seq_next,
 238         .stop  = dev_mc_seq_stop,
 239         .show  = dev_mc_seq_show,
 240 };
 241
 242 static int dev_mc_seq_open(struct inode *inode, struct file *file)
 243 {
 244         struct seq_file *seq;
 245         int res;
 246         res = seq_open(file, &dev_mc_seq_ops);
 247         if (!res) {
 248                 seq = file->private_data;
 249                 seq->private = get_proc_net(inode);
 250                 if (!seq->private) {
 251                         seq_release(inode, file);
 252                         res = -ENXIO;
 253                 }
 254         }
 255         return res;
 256 }
 257
 258 static int dev_mc_seq_release(struct inode *inode, struct file *file)
 259 {
 260         struct seq_file *seq = file->private_data;
 261         struct net *net = seq->private;
 262         put_net(net);
 263         return seq_release(inode, file);
 264 }
 265
 266 static const struct file_operations dev_mc_seq_fops = {
 267         .owner   = THIS_MODULE,
 268         .open    = dev_mc_seq_open,
 269         .read    = seq_read,
 270         .llseek  = seq_lseek,
 271         .release = dev_mc_seq_release,
 272 };
 273
 274 #endif
 275
 276 static int __net_init dev_mc_net_init(struct net *net)
 277 {
 278         if (!proc_net_fops_create(net, "dev_mcast", 0, &dev_mc_seq_fops))
 279                 return -ENOMEM;
 280         return 0;
 281 }
 282
 283 static void __net_exit dev_mc_net_exit(struct net *net)
 284 {
 285         proc_net_remove(net, "dev_mcast");
 286 }
 287
 288 static struct pernet_operations dev_mc_net_ops = {
 289         .init = dev_mc_net_init,
 290         .exit = dev_mc_net_exit,
 291 };
 292
 293 void __init dev_mcast_init(void)
 294 {
 295         register_pernet_subsys(&dev_mc_net_ops);
 296 }
 297
 298 EXPORT_SYMBOL(dev_mc_add);
 299 EXPORT_SYMBOL(dev_mc_delete);