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/sched.h>
  31 #include <linux/string.h>
  32 #include <linux/mm.h>
  33 #include <linux/socket.h>
  34 #include <linux/sockios.h>
  35 #include <linux/in.h>
  36 #include <linux/errno.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/if_ether.h>
  39 #include <linux/inet.h>
  40 #include <linux/netdevice.h>
  41 #include <linux/etherdevice.h>
  42 #include <linux/proc_fs.h>
  43 #include <linux/seq_file.h>
  44 #include <linux/init.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  *      Update the multicast list into the physical NIC controller.
  69  */
  70
  71 static void __dev_mc_upload(struct net_device *dev)
  72 {
  73         /* Don't do anything till we up the interface
  74          * [dev_open will call this function so the list will
  75          * stay sane]
  76          */
  77
  78         if (!(dev->flags&IFF_UP))
  79                 return;
  80
  81         /*
  82          *      Devices with no set multicast or which have been
  83          *      detached don't get set.
  84          */
  85
  86         if (dev->set_multicast_list == NULL ||
  87             !netif_device_present(dev))
  88                 return;
  89
  90         dev->set_multicast_list(dev);
  91 }
  92
  93 void dev_mc_upload(struct net_device *dev)
  94 {
  95         netif_tx_lock_bh(dev);
  96         __dev_mc_upload(dev);
  97         netif_tx_unlock_bh(dev);
  98 }
  99
 100 /*
 101  *      Delete a device level multicast
 102  */
 103
 104 int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
 105 {
 106         int err = 0;
 107         struct dev_mc_list *dmi, **dmip;
 108
 109         netif_tx_lock_bh(dev);
 110
 111         for (dmip = &dev->mc_list; (dmi = *dmip) != NULL; dmip = &dmi->next) {
 112                 /*
 113                  *      Find the entry we want to delete. The device could
 114                  *      have variable length entries so check these too.
 115                  */
 116                 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
 117                     alen == dmi->dmi_addrlen) {
 118                         if (glbl) {
 119                                 int old_glbl = dmi->dmi_gusers;
 120                                 dmi->dmi_gusers = 0;
 121                                 if (old_glbl == 0)
 122                                         break;
 123                         }
 124                         if (--dmi->dmi_users)
 125                                 goto done;
 126
 127                         /*
 128                          *      Last user. So delete the entry.
 129                          */
 130                         *dmip = dmi->next;
 131                         dev->mc_count--;
 132
 133                         kfree(dmi);
 134
 135                         /*
 136                          *      We have altered the list, so the card
 137                          *      loaded filter is now wrong. Fix it
 138                          */
 139                         __dev_mc_upload(dev);
 140
 141                         netif_tx_unlock_bh(dev);
 142                         return 0;
 143                 }
 144         }
 145         err = -ENOENT;
 146 done:
 147         netif_tx_unlock_bh(dev);
 148         return err;
 149 }
 150
 151 /*
 152  *      Add a device level multicast
 153  */
 154
 155 int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
 156 {
 157         int err = 0;
 158         struct dev_mc_list *dmi, *dmi1;
 159
 160         dmi1 = kmalloc(sizeof(*dmi), GFP_ATOMIC);
 161
 162         netif_tx_lock_bh(dev);
 163         for (dmi = dev->mc_list; dmi != NULL; dmi = dmi->next) {
 164                 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
 165                     dmi->dmi_addrlen == alen) {
 166                         if (glbl) {
 167                                 int old_glbl = dmi->dmi_gusers;
 168                                 dmi->dmi_gusers = 1;
 169                                 if (old_glbl)
 170                                         goto done;
 171                         }
 172                         dmi->dmi_users++;
 173                         goto done;
 174                 }
 175         }
 176
 177         if ((dmi = dmi1) == NULL) {
 178                 netif_tx_unlock_bh(dev);
 179                 return -ENOMEM;
 180         }
 181         memcpy(dmi->dmi_addr, addr, alen);
 182         dmi->dmi_addrlen = alen;
 183         dmi->next = dev->mc_list;
 184         dmi->dmi_users = 1;
 185         dmi->dmi_gusers = glbl ? 1 : 0;
 186         dev->mc_list = dmi;
 187         dev->mc_count++;
 188
 189         __dev_mc_upload(dev);
 190
 191         netif_tx_unlock_bh(dev);
 192         return 0;
 193
 194 done:
 195         netif_tx_unlock_bh(dev);
 196         kfree(dmi1);
 197         return err;
 198 }
 199
 200 /*
 201  *      Discard multicast list when a device is downed
 202  */
 203
 204 void dev_mc_discard(struct net_device *dev)
 205 {
 206         netif_tx_lock_bh(dev);
 207
 208         while (dev->mc_list != NULL) {
 209                 struct dev_mc_list *tmp = dev->mc_list;
 210                 dev->mc_list = tmp->next;
 211                 if (tmp->dmi_users > tmp->dmi_gusers)
 212                         printk("dev_mc_discard: multicast leakage! dmi_users=%d\n", tmp->dmi_users);
 213                 kfree(tmp);
 214         }
 215         dev->mc_count = 0;
 216
 217         netif_tx_unlock_bh(dev);
 218 }
 219
 220 #ifdef CONFIG_PROC_FS
 221 static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
 222 {
 223         struct net_device *dev;
 224         loff_t off = 0;
 225
 226         read_lock(&dev_base_lock);
 227         for (dev = dev_base; dev; dev = dev->next) {
 228                 if (off++ == *pos)
 229                         return dev;
 230         }
 231         return NULL;
 232 }
 233
 234 static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 235 {
 236         struct net_device *dev = v;
 237         ++*pos;
 238         return dev->next;
 239 }
 240
 241 static void dev_mc_seq_stop(struct seq_file *seq, void *v)
 242 {
 243         read_unlock(&dev_base_lock);
 244 }
 245
 246
 247 static int dev_mc_seq_show(struct seq_file *seq, void *v)
 248 {
 249         struct dev_mc_list *m;
 250         struct net_device *dev = v;
 251
 252         netif_tx_lock_bh(dev);
 253         for (m = dev->mc_list; m; m = m->next) {
 254                 int i;
 255
 256                 seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
 257                            dev->name, m->dmi_users, m->dmi_gusers);
 258
 259                 for (i = 0; i < m->dmi_addrlen; i++)
 260                         seq_printf(seq, "%02x", m->dmi_addr[i]);
 261
 262                 seq_putc(seq, '\n');
 263         }
 264         netif_tx_unlock_bh(dev);
 265         return 0;
 266 }
 267
 268 static struct seq_operations dev_mc_seq_ops = {
 269         .start = dev_mc_seq_start,
 270         .next  = dev_mc_seq_next,
 271         .stop  = dev_mc_seq_stop,
 272         .show  = dev_mc_seq_show,
 273 };
 274
 275 static int dev_mc_seq_open(struct inode *inode, struct file *file)
 276 {
 277         return seq_open(file, &dev_mc_seq_ops);
 278 }
 279
 280 static struct file_operations dev_mc_seq_fops = {
 281         .owner   = THIS_MODULE,
 282         .open    = dev_mc_seq_open,
 283         .read    = seq_read,
 284         .llseek  = seq_lseek,
 285         .release = seq_release,
 286 };
 287
 288 #endif
 289
 290 void __init dev_mcast_init(void)
 291 {
 292         proc_net_fops_create("dev_mcast", 0, &dev_mc_seq_fops);
 293 }
 294
 295 EXPORT_SYMBOL(dev_mc_add);
 296 EXPORT_SYMBOL(dev_mc_delete);
 297 EXPORT_SYMBOL(dev_mc_upload);