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
  63 /*
  64  *      Update the multicast list into the physical NIC controller.
  65  */
  66
  67 void dev_mc_upload(struct device *dev)
  68 {
  69         /* Don't do anything till we up the interface
  70            [dev_open will call this function so the list will
  71             stay sane] */
  72
  73         if(!(dev->flags&IFF_UP))
  74                 return;
  75
  76         /*
  77          *      Devices with no set multicast don't get set
  78          */
  79
  80         if(dev->set_multicast_list==NULL)
  81                 return;
  82
  83         start_bh_atomic();
  84         dev->set_multicast_list(dev);
  85         end_bh_atomic();
  86 }
  87
  88 /*
  89  *      Delete a device level multicast
  90  */
  91
  92 int dev_mc_delete(struct device *dev, void *addr, int alen, int glbl)
  93 {
  94         int err = 0;
  95         struct dev_mc_list *dmi, **dmip;
  96
  97         start_bh_atomic();
  98         for (dmip=&dev->mc_list; (dmi=*dmip)!=NULL; dmip=&dmi->next) {
  99                 /*
 100                  *      Find the entry we want to delete. The device could
 101                  *      have variable length entries so check these too.
 102                  */
 103                 if (memcmp(dmi->dmi_addr,addr,dmi->dmi_addrlen)==0 && alen==dmi->dmi_addrlen) {
 104                         if (glbl) {
 105                                 int old_glbl = dmi->dmi_gusers;
 106                                 dmi->dmi_gusers = 0;
 107                                 if (old_glbl == 0)
 108                                         break;
 109                         }
 110                         if(--dmi->dmi_users)
 111                                 goto done;
 112
 113                         /*
 114                          *      Last user. So delete the entry.
 115                          */
 116                         *dmip = dmi->next;
 117                         dev->mc_count--;
 118                         kfree_s(dmi,sizeof(*dmi));
 119                         /*
 120                          *      We have altered the list, so the card
 121                          *      loaded filter is now wrong. Fix it
 122                          */
 123                         end_bh_atomic();
 124                         dev_mc_upload(dev);
 125                         return 0;
 126                 }
 127         }
 128         err = -ENOENT;
 129 done:
 130         end_bh_atomic();
 131         return err;
 132 }
 133
 134 /*
 135  *      Add a device level multicast
 136  */
 137
 138 int dev_mc_add(struct device *dev, void *addr, int alen, int glbl)
 139 {
 140         int err = 0;
 141         struct dev_mc_list *dmi, *dmi1;
 142
 143         dmi1 = (struct dev_mc_list *)kmalloc(sizeof(*dmi), gfp_any());
 144
 145         start_bh_atomic();
 146         for(dmi=dev->mc_list; dmi!=NULL; dmi=dmi->next) {
 147                 if (memcmp(dmi->dmi_addr,addr,dmi->dmi_addrlen)==0 && dmi->dmi_addrlen==alen) {
 148                         if (glbl) {
 149                                 int old_glbl = dmi->dmi_gusers;
 150                                 dmi->dmi_gusers = 1;
 151                                 if (old_glbl)
 152                                         goto done;
 153                         }
 154                         dmi->dmi_users++;
 155                         goto done;
 156                 }
 157         }
 158
 159         if ((dmi=dmi1)==NULL)
 160                 return -ENOMEM;
 161         memcpy(dmi->dmi_addr, addr, alen);
 162         dmi->dmi_addrlen=alen;
 163         dmi->next=dev->mc_list;
 164         dmi->dmi_users=1;
 165         dmi->dmi_gusers=glbl ? 1 : 0;
 166         dev->mc_list=dmi;
 167         dev->mc_count++;
 168         end_bh_atomic();
 169         dev_mc_upload(dev);
 170         return 0;
 171
 172 done:
 173         end_bh_atomic();
 174         if (dmi1)
 175                 kfree(dmi1);
 176         return err;
 177 }
 178
 179 /*
 180  *      Discard multicast list when a device is downed
 181  */
 182
 183 void dev_mc_discard(struct device *dev)
 184 {
 185         start_bh_atomic();
 186         while (dev->mc_list!=NULL) {
 187                 struct dev_mc_list *tmp=dev->mc_list;
 188                 dev->mc_list=tmp->next;
 189                 if (tmp->dmi_users > tmp->dmi_gusers)
 190                         printk("dev_mc_discard: multicast leakage! dmi_users=%d\n", tmp->dmi_users);
 191                 kfree_s(tmp,sizeof(*tmp));
 192         }
 193         dev->mc_count=0;
 194         end_bh_atomic();
 195 }
 196
 197 #ifdef CONFIG_PROC_FS
 198 static int dev_mc_read_proc(char *buffer, char **start, off_t offset,
 199                             int length, int *eof, void *data)
 200 {
 201         off_t pos=0, begin=0;
 202         struct dev_mc_list *m;
 203         int len=0;
 204         struct device *dev;
 205
 206         start_bh_atomic();
 207
 208         for (dev = dev_base; dev; dev = dev->next) {
 209                 for (m = dev->mc_list; m; m = m->next) {
 210                         int i;
 211
 212                         len += sprintf(buffer+len,"%-4d %-15s %-5d %-5d ", dev->ifindex, dev->name,
 213                                        m->dmi_users, m->dmi_gusers);
 214
 215                         for (i=0; i<m->dmi_addrlen; i++)
 216                                 len += sprintf(buffer+len, "%02x", m->dmi_addr[i]);
 217
 218                         len+=sprintf(buffer+len, "\n");
 219
 220                         pos=begin+len;
 221                         if (pos < offset) {
 222                                 len=0;
 223                                 begin=pos;
 224                         }
 225                         if (pos > offset+length)
 226                                 goto done;
 227                 }
 228         }
 229         *eof = 1;
 230
 231 done:
 232         end_bh_atomic();
 233         *start=buffer+(offset-begin);
 234         len-=(offset-begin);
 235         if(len>length)
 236                 len=length;
 237         if(len<0)
 238                 len=0;
 239         return len;
 240 }
 241 #endif
 242
 243 __initfunc(void dev_mcast_init(void))
 244 {
 245 #ifdef CONFIG_PROC_FS
 246         struct proc_dir_entry *ent;
 247
 248         ent = create_proc_entry("net/dev_mcast", 0, 0);
 249         ent->read_proc = dev_mc_read_proc;
 250 #endif
 251 }
 252