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 <asm/uaccess.h>
  26 #include <asm/system.h>
  27 #include <asm/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/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 dev->xmit_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         spin_lock_bh(&dev->xmit_lock);
  95         __dev_mc_upload(dev);
  96         spin_unlock_bh(&dev->xmit_lock);
  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 = 0;
 106         struct dev_mc_list *dmi, **dmip;
 107
 108         spin_lock_bh(&dev->xmit_lock);
 109
 110         for (dmip = &dev->mc_list; (dmi = *dmip) != NULL; dmip = &dmi->next) {
 111                 /*
 112                  *      Find the entry we want to delete. The device could
 113                  *      have variable length entries so check these too.
 114                  */
 115                 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
 116                     alen == dmi->dmi_addrlen) {
 117                         if (glbl) {
 118                                 int old_glbl = dmi->dmi_gusers;
 119                                 dmi->dmi_gusers = 0;
 120                                 if (old_glbl == 0)
 121                                         break;
 122                         }
 123                         if (--dmi->dmi_users)
 124                                 goto done;
 125
 126                         /*
 127                          *      Last user. So delete the entry.
 128                          */
 129                         *dmip = dmi->next;
 130                         dev->mc_count--;
 131
 132                         kfree(dmi);
 133
 134                         /*
 135                          *      We have altered the list, so the card
 136                          *      loaded filter is now wrong. Fix it
 137                          */
 138                         __dev_mc_upload(dev);
 139
 140                         spin_unlock_bh(&dev->xmit_lock);
 141                         return 0;
 142                 }
 143         }
 144         err = -ENOENT;
 145 done:
 146         spin_unlock_bh(&dev->xmit_lock);
 147         return err;
 148 }
 149
 150 /*
 151  *      Add a device level multicast
 152  */
 153
 154 int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
 155 {
 156         int err = 0;
 157         struct dev_mc_list *dmi, *dmi1;
 158
 159         dmi1 = (struct dev_mc_list *)kmalloc(sizeof(*dmi), GFP_ATOMIC);
 160
 161         spin_lock_bh(&dev->xmit_lock);
 162         for (dmi = dev->mc_list; dmi != NULL; dmi = dmi->next) {
 163                 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
 164                     dmi->dmi_addrlen == alen) {
 165                         if (glbl) {
 166                                 int old_glbl = dmi->dmi_gusers;
 167                                 dmi->dmi_gusers = 1;
 168                                 if (old_glbl)
 169                                         goto done;
 170                         }
 171                         dmi->dmi_users++;
 172                         goto done;
 173                 }
 174         }
 175
 176         if ((dmi = dmi1) == NULL) {
 177                 spin_unlock_bh(&dev->xmit_lock);
 178                 return -ENOMEM;
 179         }
 180         memcpy(dmi->dmi_addr, addr, alen);
 181         dmi->dmi_addrlen = alen;
 182         dmi->next = dev->mc_list;
 183         dmi->dmi_users = 1;
 184         dmi->dmi_gusers = glbl ? 1 : 0;
 185         dev->mc_list = dmi;
 186         dev->mc_count++;
 187
 188         __dev_mc_upload(dev);
 189
 190         spin_unlock_bh(&dev->xmit_lock);
 191         return 0;
 192
 193 done:
 194         spin_unlock_bh(&dev->xmit_lock);
 195         if (dmi1)
 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         spin_lock_bh(&dev->xmit_lock);
 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         spin_unlock_bh(&dev->xmit_lock);
 218 }
 219
 220 #ifdef CONFIG_PROC_FS
 221 static int dev_mc_read_proc(char *buffer, char **start, off_t offset,
 222                             int length, int *eof, void *data)
 223 {
 224         off_t pos = 0, begin = 0;
 225         struct dev_mc_list *m;
 226         int len = 0;
 227         struct net_device *dev;
 228
 229         read_lock(&dev_base_lock);
 230         for (dev = dev_base; dev; dev = dev->next) {
 231                 spin_lock_bh(&dev->xmit_lock);
 232                 for (m = dev->mc_list; m; m = m->next) {
 233                         int i;
 234
 235                         len += sprintf(buffer+len,"%-4d %-15s %-5d %-5d ", dev->ifindex,
 236                                        dev->name, m->dmi_users, m->dmi_gusers);
 237
 238                         for (i = 0; i < m->dmi_addrlen; i++)
 239                                 len += sprintf(buffer+len, "%02x", m->dmi_addr[i]);
 240
 241                         len += sprintf(buffer+len, "\n");
 242
 243                         pos = begin + len;
 244                         if (pos < offset) {
 245                                 len = 0;
 246                                 begin = pos;
 247                         }
 248                         if (pos > offset + length) {
 249                                 spin_unlock_bh(&dev->xmit_lock);
 250                                 goto done;
 251                         }
 252                 }
 253                 spin_unlock_bh(&dev->xmit_lock);
 254         }
 255         *eof = 1;
 256
 257 done:
 258         read_unlock(&dev_base_lock);
 259         *start = buffer + (offset - begin);
 260         len -= (offset - begin);
 261         if (len > length)
 262                 len = length;
 263         if (len < 0)
 264                 len = 0;
 265         return len;
 266 }
 267 #endif
 268
 269 void __init dev_mcast_init(void)
 270 {
 271 #ifdef CONFIG_PROC_FS
 272         create_proc_read_entry("net/dev_mcast", 0, 0, dev_mc_read_proc, NULL);
 273 #endif
 274 }
 275