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  *
  17  *      This program is free software; you can redistribute it and/or
  18  *      modify it under the terms of the GNU General Public License
  19  *      as published by the Free Software Foundation; either version
  20  *      2 of the License, or (at your option) any later version.
  21  */
  22
  23 #include <linux/config.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/system.h>
  26 #include <asm/bitops.h>
  27 #include <linux/types.h>
  28 #include <linux/kernel.h>
  29 #include <linux/sched.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/init.h>
  43 #include <net/ip.h>
  44 #include <net/route.h>
  45 #include <linux/skbuff.h>
  46 #include <net/sock.h>
  47 #include <net/arp.h>
  48
  49
  50 /*
  51  *      Device multicast list maintenance.
  52  *
  53  *      This is used both by IP and by the user level maintenance functions.
  54  *      Unlike BSD we maintain a usage count on a given multicast address so
  55  *      that a casual user application can add/delete multicasts used by
  56  *      protocols without doing damage to the protocols when it deletes the
  57  *      entries. It also helps IP as it tracks overlapping maps.
  58  *
  59  *      Device mc lists are changed by bh at least if IPv6 is enabled,
  60  *      so that it must be bh protected.
  61  *
  62  *      We protect all mc lists with global rw lock
  63  *      and block accesses to device mc filters with dev->xmit_lock.
  64  */
  65 static rwlock_t dev_mc_lock = RW_LOCK_UNLOCKED;
  66
  67 /*
  68  *      Update the multicast list into the physical NIC controller.
  69  */
  70
  71 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         read_lock_bh(&dev_mc_lock);
  91         spin_lock(&dev->xmit_lock);
  92         dev->xmit_lock_owner = smp_processor_id();
  93         dev->set_multicast_list(dev);
  94         dev->xmit_lock_owner = -1;
  95         spin_unlock(&dev->xmit_lock);
  96         read_unlock_bh(&dev_mc_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         write_lock_bh(&dev_mc_lock);
 109         for (dmip = &dev->mc_list; (dmi = *dmip) != NULL; dmip = &dmi->next) {
 110                 /*
 111                  *      Find the entry we want to delete. The device could
 112                  *      have variable length entries so check these too.
 113                  */
 114                 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
 115                     alen == dmi->dmi_addrlen) {
 116                         if (glbl) {
 117                                 int old_glbl = dmi->dmi_gusers;
 118                                 dmi->dmi_gusers = 0;
 119                                 if (old_glbl == 0)
 120                                         break;
 121                         }
 122                         if (--dmi->dmi_users)
 123                                 goto done;
 124
 125                         /*
 126                          *      Last user. So delete the entry.
 127                          */
 128                         *dmip = dmi->next;
 129                         dev->mc_count--;
 130                         write_unlock_bh(&dev_mc_lock);
 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                         return 0;
 140                 }
 141         }
 142         err = -ENOENT;
 143 done:
 144         write_unlock_bh(&dev_mc_lock);
 145         return err;
 146 }
 147
 148 /*
 149  *      Add a device level multicast
 150  */
 151
 152 int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
 153 {
 154         int err = 0;
 155         struct dev_mc_list *dmi, *dmi1;
 156
 157         dmi1 = (struct dev_mc_list *)kmalloc(sizeof(*dmi), GFP_ATOMIC);
 158
 159         write_lock_bh(&dev_mc_lock);
 160         for (dmi = dev->mc_list; dmi != NULL; dmi = dmi->next) {
 161                 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
 162                     dmi->dmi_addrlen == alen) {
 163                         if (glbl) {
 164                                 int old_glbl = dmi->dmi_gusers;
 165                                 dmi->dmi_gusers = 1;
 166                                 if (old_glbl)
 167                                         goto done;
 168                         }
 169                         dmi->dmi_users++;
 170                         goto done;
 171                 }
 172         }
 173
 174         if ((dmi = dmi1) == NULL) {
 175                 write_unlock_bh(&dev_mc_lock);
 176                 return -ENOMEM;
 177         }
 178         memcpy(dmi->dmi_addr, addr, alen);
 179         dmi->dmi_addrlen = alen;
 180         dmi->next = dev->mc_list;
 181         dmi->dmi_users = 1;
 182         dmi->dmi_gusers = glbl ? 1 : 0;
 183         dev->mc_list = dmi;
 184         dev->mc_count++;
 185         write_unlock_bh(&dev_mc_lock);
 186         dev_mc_upload(dev);
 187         return 0;
 188
 189 done:
 190         write_unlock_bh(&dev_mc_lock);
 191         if (dmi1)
 192                 kfree(dmi1);
 193         return err;
 194 }
 195
 196 /*
 197  *      Discard multicast list when a device is downed
 198  */
 199
 200 void dev_mc_discard(struct net_device *dev)
 201 {
 202         write_lock_bh(&dev_mc_lock);
 203         while (dev->mc_list != NULL) {
 204                 struct dev_mc_list *tmp = dev->mc_list;
 205                 dev->mc_list = tmp->next;
 206                 if (tmp->dmi_users > tmp->dmi_gusers)
 207                         printk("dev_mc_discard: multicast leakage! dmi_users=%d\n", tmp->dmi_users);
 208                 kfree(tmp);
 209         }
 210         dev->mc_count = 0;
 211         write_unlock_bh(&dev_mc_lock);
 212 }
 213
 214 #ifdef CONFIG_PROC_FS
 215 static int dev_mc_read_proc(char *buffer, char **start, off_t offset,
 216                             int length, int *eof, void *data)
 217 {
 218         off_t pos = 0, begin = 0;
 219         struct dev_mc_list *m;
 220         int len = 0;
 221         struct net_device *dev;
 222
 223         read_lock(&dev_base_lock);
 224         for (dev = dev_base; dev; dev = dev->next) {
 225                 read_lock_bh(&dev_mc_lock);
 226                 for (m = dev->mc_list; m; m = m->next) {
 227                         int i;
 228
 229                         len += sprintf(buffer+len,"%-4d %-15s %-5d %-5d ", dev->ifindex,
 230                                        dev->name, m->dmi_users, m->dmi_gusers);
 231
 232                         for (i = 0; i < m->dmi_addrlen; i++)
 233                                 len += sprintf(buffer+len, "%02x", m->dmi_addr[i]);
 234
 235                         len += sprintf(buffer+len, "\n");
 236
 237                         pos = begin + len;
 238                         if (pos < offset) {
 239                                 len = 0;
 240                                 begin = pos;
 241                         }
 242                         if (pos > offset + length) {
 243                                 read_unlock_bh(&dev_mc_lock);
 244                                 goto done;
 245                         }
 246                 }
 247                 read_unlock_bh(&dev_mc_lock);
 248         }
 249         *eof = 1;
 250
 251 done:
 252         read_unlock(&dev_base_lock);
 253         *start = buffer + (offset - begin);
 254         len -= (offset - begin);
 255         if (len > length)
 256                 len = length;
 257         if (len < 0)
 258                 len = 0;
 259         return len;
 260 }
 261 #endif
 262
 263 void __init dev_mcast_init(void)
 264 {
 265 #ifdef CONFIG_PROC_FS
 266         create_proc_read_entry("net/dev_mcast", 0, 0, dev_mc_read_proc, NULL);
 267 #endif
 268 }
 269