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, &dev->mc_count,
  76                                 addr, alen, glbl);
  77         if (!err) {
  78                 /*
  79                  *      We have altered the list, so the card
  80                  *      loaded filter is now wrong. Fix it
  81                  */
  82
  83                 __dev_set_rx_mode(dev);
  84         }
  85         netif_tx_unlock_bh(dev);
  86         return err;
  87 }
  88
  89 /*
  90  *      Add a device level multicast
  91  */
  92
  93 int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
  94 {
  95         int err;
  96
  97         netif_tx_lock_bh(dev);
  98         err = __dev_addr_add(&dev->mc_list, &dev->mc_count, addr, alen, glbl);
  99         if (!err)
 100                 __dev_set_rx_mode(dev);
 101         netif_tx_unlock_bh(dev);
 102         return err;
 103 }
 104
 105 /**
 106  *      dev_mc_sync     - Synchronize device's multicast list to another device
 107  *      @to: destination device
 108  *      @from: source device
 109  *
 110  *      Add newly added addresses to the destination device and release
 111  *      addresses that have no users left. The source device must be
 112  *      locked by netif_tx_lock_bh.
 113  *
 114  *      This function is intended to be called from the dev->set_multicast_list
 115  *      function of layered software devices.
 116  */
 117 int dev_mc_sync(struct net_device *to, struct net_device *from)
 118 {
 119         struct dev_addr_list *da;
 120         int err = 0;
 121
 122         netif_tx_lock_bh(to);
 123         for (da = from->mc_list; da != NULL; da = da->next) {
 124                 if (!da->da_synced) {
 125                         err = __dev_addr_add(&to->mc_list, &to->mc_count,
 126                                              da->da_addr, da->da_addrlen, 0);
 127                         if (err < 0)
 128                                 break;
 129                         da->da_synced = 1;
 130                         da->da_users++;
 131                 } else if (da->da_users == 1) {
 132                         __dev_addr_delete(&to->mc_list, &to->mc_count,
 133                                           da->da_addr, da->da_addrlen, 0);
 134                         __dev_addr_delete(&from->mc_list, &from->mc_count,
 135                                           da->da_addr, da->da_addrlen, 0);
 136                 }
 137         }
 138         if (!err)
 139                 __dev_set_rx_mode(to);
 140         netif_tx_unlock_bh(to);
 141
 142         return err;
 143 }
 144 EXPORT_SYMBOL(dev_mc_sync);
 145
 146
 147 /**
 148  *      dev_mc_unsync   - Remove synchronized addresses from the destination
 149  *                        device
 150  *      @to: destination device
 151  *      @from: source device
 152  *
 153  *      Remove all addresses that were added to the destination device by
 154  *      dev_mc_sync(). This function is intended to be called from the
 155  *      dev->stop function of layered software devices.
 156  */
 157 void dev_mc_unsync(struct net_device *to, struct net_device *from)
 158 {
 159         struct dev_addr_list *da;
 160
 161         netif_tx_lock_bh(from);
 162         netif_tx_lock_bh(to);
 163
 164         for (da = from->mc_list; da != NULL; da = da->next) {
 165                 if (!da->da_synced)
 166                         continue;
 167                 __dev_addr_delete(&to->mc_list, &to->mc_count,
 168                                   da->da_addr, da->da_addrlen, 0);
 169                 da->da_synced = 0;
 170                 __dev_addr_delete(&from->mc_list, &from->mc_count,
 171                                   da->da_addr, da->da_addrlen, 0);
 172         }
 173         __dev_set_rx_mode(to);
 174
 175         netif_tx_unlock_bh(to);
 176         netif_tx_unlock_bh(from);
 177 }
 178 EXPORT_SYMBOL(dev_mc_unsync);
 179
 180 /*
 181  *      Discard multicast list when a device is downed
 182  */
 183
 184 void dev_mc_discard(struct net_device *dev)
 185 {
 186         netif_tx_lock_bh(dev);
 187         __dev_addr_discard(&dev->mc_list);
 188         dev->mc_count = 0;
 189         netif_tx_unlock_bh(dev);
 190 }
 191
 192 #ifdef CONFIG_PROC_FS
 193 static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
 194 {
 195         struct net_device *dev;
 196         loff_t off = 0;
 197
 198         read_lock(&dev_base_lock);
 199         for_each_netdev(dev) {
 200                 if (off++ == *pos)
 201                         return dev;
 202         }
 203         return NULL;
 204 }
 205
 206 static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 207 {
 208         ++*pos;
 209         return next_net_device((struct net_device *)v);
 210 }
 211
 212 static void dev_mc_seq_stop(struct seq_file *seq, void *v)
 213 {
 214         read_unlock(&dev_base_lock);
 215 }
 216
 217
 218 static int dev_mc_seq_show(struct seq_file *seq, void *v)
 219 {
 220         struct dev_addr_list *m;
 221         struct net_device *dev = v;
 222
 223         netif_tx_lock_bh(dev);
 224         for (m = dev->mc_list; m; m = m->next) {
 225                 int i;
 226
 227                 seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
 228                            dev->name, m->dmi_users, m->dmi_gusers);
 229
 230                 for (i = 0; i < m->dmi_addrlen; i++)
 231                         seq_printf(seq, "%02x", m->dmi_addr[i]);
 232
 233                 seq_putc(seq, '\n');
 234         }
 235         netif_tx_unlock_bh(dev);
 236         return 0;
 237 }
 238
 239 static const struct seq_operations dev_mc_seq_ops = {
 240         .start = dev_mc_seq_start,
 241         .next  = dev_mc_seq_next,
 242         .stop  = dev_mc_seq_stop,
 243         .show  = dev_mc_seq_show,
 244 };
 245
 246 static int dev_mc_seq_open(struct inode *inode, struct file *file)
 247 {
 248         return seq_open(file, &dev_mc_seq_ops);
 249 }
 250
 251 static const struct file_operations dev_mc_seq_fops = {
 252         .owner   = THIS_MODULE,
 253         .open    = dev_mc_seq_open,
 254         .read    = seq_read,
 255         .llseek  = seq_lseek,
 256         .release = seq_release,
 257 };
 258
 259 #endif
 260
 261 void __init dev_mcast_init(void)
 262 {
 263         proc_net_fops_create("dev_mcast", 0, &dev_mc_seq_fops);
 264 }
 265
 266 EXPORT_SYMBOL(dev_mc_add);
 267 EXPORT_SYMBOL(dev_mc_delete);