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  *      Update the multicast list into the physical NIC controller.
  68  */
  69
  70 static void __dev_mc_upload(struct net_device *dev)
  71 {
  72         /* Don't do anything till we up the interface
  73          * [dev_open will call this function so the list will
  74          * stay sane]
  75          */
  76
  77         if (!(dev->flags&IFF_UP))
  78                 return;
  79
  80         /*
  81          *      Devices with no set multicast or which have been
  82          *      detached don't get set.
  83          */
  84
  85         if (dev->set_multicast_list == NULL ||
  86             !netif_device_present(dev))
  87                 return;
  88
  89         dev->set_multicast_list(dev);
  90 }
  91
  92 void dev_mc_upload(struct net_device *dev)
  93 {
  94         netif_tx_lock_bh(dev);
  95         __dev_mc_upload(dev);
  96         netif_tx_unlock_bh(dev);
  97 }
  98
  99 /*
 100  *      Delete a device level multicast
 101  */
 102
 103 int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
 104 {
 105         int err;
 106
 107         netif_tx_lock_bh(dev);
 108         err = __dev_addr_delete(&dev->mc_list, addr, alen, glbl);
 109         if (!err) {
 110                 dev->mc_count--;
 111
 112                 /*
 113                  *      We have altered the list, so the card
 114                  *      loaded filter is now wrong. Fix it
 115                  */
 116
 117                 __dev_mc_upload(dev);
 118         }
 119         netif_tx_unlock_bh(dev);
 120         return err;
 121 }
 122
 123 /*
 124  *      Add a device level multicast
 125  */
 126
 127 int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
 128 {
 129         int err;
 130
 131         netif_tx_lock_bh(dev);
 132         err = __dev_addr_add(&dev->mc_list, addr, alen, glbl);
 133         if (!err) {
 134                 dev->mc_count++;
 135                 __dev_mc_upload(dev);
 136         }
 137         netif_tx_unlock_bh(dev);
 138         return err;
 139 }
 140
 141 /*
 142  *      Discard multicast list when a device is downed
 143  */
 144
 145 void dev_mc_discard(struct net_device *dev)
 146 {
 147         netif_tx_lock_bh(dev);
 148         __dev_addr_discard(&dev->mc_list);
 149         dev->mc_count = 0;
 150         netif_tx_unlock_bh(dev);
 151 }
 152
 153 #ifdef CONFIG_PROC_FS
 154 static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
 155 {
 156         struct net_device *dev;
 157         loff_t off = 0;
 158
 159         read_lock(&dev_base_lock);
 160         for_each_netdev(dev) {
 161                 if (off++ == *pos)
 162                         return dev;
 163         }
 164         return NULL;
 165 }
 166
 167 static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 168 {
 169         ++*pos;
 170         return next_net_device((struct net_device *)v);
 171 }
 172
 173 static void dev_mc_seq_stop(struct seq_file *seq, void *v)
 174 {
 175         read_unlock(&dev_base_lock);
 176 }
 177
 178
 179 static int dev_mc_seq_show(struct seq_file *seq, void *v)
 180 {
 181         struct dev_addr_list *m;
 182         struct net_device *dev = v;
 183
 184         netif_tx_lock_bh(dev);
 185         for (m = dev->mc_list; m; m = m->next) {
 186                 int i;
 187
 188                 seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
 189                            dev->name, m->dmi_users, m->dmi_gusers);
 190
 191                 for (i = 0; i < m->dmi_addrlen; i++)
 192                         seq_printf(seq, "%02x", m->dmi_addr[i]);
 193
 194                 seq_putc(seq, '\n');
 195         }
 196         netif_tx_unlock_bh(dev);
 197         return 0;
 198 }
 199
 200 static const struct seq_operations dev_mc_seq_ops = {
 201         .start = dev_mc_seq_start,
 202         .next  = dev_mc_seq_next,
 203         .stop  = dev_mc_seq_stop,
 204         .show  = dev_mc_seq_show,
 205 };
 206
 207 static int dev_mc_seq_open(struct inode *inode, struct file *file)
 208 {
 209         return seq_open(file, &dev_mc_seq_ops);
 210 }
 211
 212 static const struct file_operations dev_mc_seq_fops = {
 213         .owner   = THIS_MODULE,
 214         .open    = dev_mc_seq_open,
 215         .read    = seq_read,
 216         .llseek  = seq_lseek,
 217         .release = seq_release,
 218 };
 219
 220 #endif
 221
 222 void __init dev_mcast_init(void)
 223 {
 224         proc_net_fops_create("dev_mcast", 0, &dev_mc_seq_fops);
 225 }
 226
 227 EXPORT_SYMBOL(dev_mc_add);
 228 EXPORT_SYMBOL(dev_mc_delete);