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/config.h>
  25 #include <linux/module.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/system.h>
  28 #include <linux/bitops.h>
  29 #include <linux/types.h>
  30 #include <linux/kernel.h>
  31 #include <linux/sched.h>
  32 #include <linux/string.h>
  33 #include <linux/mm.h>
  34 #include <linux/socket.h>
  35 #include <linux/sockios.h>
  36 #include <linux/in.h>
  37 #include <linux/errno.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/if_ether.h>
  40 #include <linux/inet.h>
  41 #include <linux/netdevice.h>
  42 #include <linux/etherdevice.h>
  43 #include <linux/proc_fs.h>
  44 #include <linux/seq_file.h>
  45 #include <linux/init.h>
  46 #include <net/ip.h>
  47 #include <net/route.h>
  48 #include <linux/skbuff.h>
  49 #include <net/sock.h>
  50 #include <net/arp.h>
  51
  52
  53 /*
  54  *      Device multicast list maintenance.
  55  *
  56  *      This is used both by IP and by the user level maintenance functions.
  57  *      Unlike BSD we maintain a usage count on a given multicast address so
  58  *      that a casual user application can add/delete multicasts used by
  59  *      protocols without doing damage to the protocols when it deletes the
  60  *      entries. It also helps IP as it tracks overlapping maps.
  61  *
  62  *      Device mc lists are changed by bh at least if IPv6 is enabled,
  63  *      so that it must be bh protected.
  64  *
  65  *      We block accesses to device mc filters with dev->xmit_lock.
  66  */
  67
  68 /*
  69  *      Update the multicast list into the physical NIC controller.
  70  */
  71
  72 static void __dev_mc_upload(struct net_device *dev)
  73 {
  74         /* Don't do anything till we up the interface
  75          * [dev_open will call this function so the list will
  76          * stay sane]
  77          */
  78
  79         if (!(dev->flags&IFF_UP))
  80                 return;
  81
  82         /*
  83          *      Devices with no set multicast or which have been
  84          *      detached don't get set.
  85          */
  86
  87         if (dev->set_multicast_list == NULL ||
  88             !netif_device_present(dev))
  89                 return;
  90
  91         dev->set_multicast_list(dev);
  92 }
  93
  94 void dev_mc_upload(struct net_device *dev)
  95 {
  96         spin_lock_bh(&dev->xmit_lock);
  97         __dev_mc_upload(dev);
  98         spin_unlock_bh(&dev->xmit_lock);
  99 }
 100
 101 /*
 102  *      Delete a device level multicast
 103  */
 104
 105 int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
 106 {
 107         int err = 0;
 108         struct dev_mc_list *dmi, **dmip;
 109
 110         spin_lock_bh(&dev->xmit_lock);
 111
 112         for (dmip = &dev->mc_list; (dmi = *dmip) != NULL; dmip = &dmi->next) {
 113                 /*
 114                  *      Find the entry we want to delete. The device could
 115                  *      have variable length entries so check these too.
 116                  */
 117                 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
 118                     alen == dmi->dmi_addrlen) {
 119                         if (glbl) {
 120                                 int old_glbl = dmi->dmi_gusers;
 121                                 dmi->dmi_gusers = 0;
 122                                 if (old_glbl == 0)
 123                                         break;
 124                         }
 125                         if (--dmi->dmi_users)
 126                                 goto done;
 127
 128                         /*
 129                          *      Last user. So delete the entry.
 130                          */
 131                         *dmip = dmi->next;
 132                         dev->mc_count--;
 133
 134                         kfree(dmi);
 135
 136                         /*
 137                          *      We have altered the list, so the card
 138                          *      loaded filter is now wrong. Fix it
 139                          */
 140                         __dev_mc_upload(dev);
 141
 142                         spin_unlock_bh(&dev->xmit_lock);
 143                         return 0;
 144                 }
 145         }
 146         err = -ENOENT;
 147 done:
 148         spin_unlock_bh(&dev->xmit_lock);
 149         return err;
 150 }
 151
 152 /*
 153  *      Add a device level multicast
 154  */
 155
 156 int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
 157 {
 158         int err = 0;
 159         struct dev_mc_list *dmi, *dmi1;
 160
 161         dmi1 = kmalloc(sizeof(*dmi), GFP_ATOMIC);
 162
 163         spin_lock_bh(&dev->xmit_lock);
 164         for (dmi = dev->mc_list; dmi != NULL; dmi = dmi->next) {
 165                 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
 166                     dmi->dmi_addrlen == alen) {
 167                         if (glbl) {
 168                                 int old_glbl = dmi->dmi_gusers;
 169                                 dmi->dmi_gusers = 1;
 170                                 if (old_glbl)
 171                                         goto done;
 172                         }
 173                         dmi->dmi_users++;
 174                         goto done;
 175                 }
 176         }
 177
 178         if ((dmi = dmi1) == NULL) {
 179                 spin_unlock_bh(&dev->xmit_lock);
 180                 return -ENOMEM;
 181         }
 182         memcpy(dmi->dmi_addr, addr, alen);
 183         dmi->dmi_addrlen = alen;
 184         dmi->next = dev->mc_list;
 185         dmi->dmi_users = 1;
 186         dmi->dmi_gusers = glbl ? 1 : 0;
 187         dev->mc_list = dmi;
 188         dev->mc_count++;
 189
 190         __dev_mc_upload(dev);
 191
 192         spin_unlock_bh(&dev->xmit_lock);
 193         return 0;
 194
 195 done:
 196         spin_unlock_bh(&dev->xmit_lock);
 197         kfree(dmi1);
 198         return err;
 199 }
 200
 201 /*
 202  *      Discard multicast list when a device is downed
 203  */
 204
 205 void dev_mc_discard(struct net_device *dev)
 206 {
 207         spin_lock_bh(&dev->xmit_lock);
 208
 209         while (dev->mc_list != NULL) {
 210                 struct dev_mc_list *tmp = dev->mc_list;
 211                 dev->mc_list = tmp->next;
 212                 if (tmp->dmi_users > tmp->dmi_gusers)
 213                         printk("dev_mc_discard: multicast leakage! dmi_users=%d\n", tmp->dmi_users);
 214                 kfree(tmp);
 215         }
 216         dev->mc_count = 0;
 217
 218         spin_unlock_bh(&dev->xmit_lock);
 219 }
 220
 221 #ifdef CONFIG_PROC_FS
 222 static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
 223 {
 224         struct net_device *dev;
 225         loff_t off = 0;
 226
 227         read_lock(&dev_base_lock);
 228         for (dev = dev_base; dev; dev = dev->next) {
 229                 if (off++ == *pos)
 230                         return dev;
 231         }
 232         return NULL;
 233 }
 234
 235 static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 236 {
 237         struct net_device *dev = v;
 238         ++*pos;
 239         return dev->next;
 240 }
 241
 242 static void dev_mc_seq_stop(struct seq_file *seq, void *v)
 243 {
 244         read_unlock(&dev_base_lock);
 245 }
 246
 247
 248 static int dev_mc_seq_show(struct seq_file *seq, void *v)
 249 {
 250         struct dev_mc_list *m;
 251         struct net_device *dev = v;
 252
 253         spin_lock_bh(&dev->xmit_lock);
 254         for (m = dev->mc_list; m; m = m->next) {
 255                 int i;
 256
 257                 seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
 258                            dev->name, m->dmi_users, m->dmi_gusers);
 259
 260                 for (i = 0; i < m->dmi_addrlen; i++)
 261                         seq_printf(seq, "%02x", m->dmi_addr[i]);
 262
 263                 seq_putc(seq, '\n');
 264         }
 265         spin_unlock_bh(&dev->xmit_lock);
 266         return 0;
 267 }
 268
 269 static struct seq_operations dev_mc_seq_ops = {
 270         .start = dev_mc_seq_start,
 271         .next  = dev_mc_seq_next,
 272         .stop  = dev_mc_seq_stop,
 273         .show  = dev_mc_seq_show,
 274 };
 275
 276 static int dev_mc_seq_open(struct inode *inode, struct file *file)
 277 {
 278         return seq_open(file, &dev_mc_seq_ops);
 279 }
 280
 281 static struct file_operations dev_mc_seq_fops = {
 282         .owner   = THIS_MODULE,
 283         .open    = dev_mc_seq_open,
 284         .read    = seq_read,
 285         .llseek  = seq_lseek,
 286         .release = seq_release,
 287 };
 288
 289 #endif
 290
 291 void __init dev_mcast_init(void)
 292 {
 293         proc_net_fops_create("dev_mcast", 0, &dev_mc_seq_fops);
 294 }
 295
 296 EXPORT_SYMBOL(dev_mc_add);
 297 EXPORT_SYMBOL(dev_mc_delete);
 298 EXPORT_SYMBOL(dev_mc_upload);