net/netlink/genetlink.c

   1 /*
   2  * NETLINK      Generic Netlink Family
   3  *
   4  *              Authors:        Jamal Hadi Salim
   5  *                              Thomas Graf <tgraf@suug.ch>
   6  *                              Johannes Berg <johannes@sipsolutions.net>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/kernel.h>
  11 #include <linux/errno.h>
  12 #include <linux/types.h>
  13 #include <linux/socket.h>
  14 #include <linux/string.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/mutex.h>
  17 #include <linux/bitmap.h>
  18 #include <net/sock.h>
  19 #include <net/genetlink.h>
  20
  21 struct sock *genl_sock = NULL;
  22
  23 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
  24
  25 static inline void genl_lock(void)
  26 {
  27         mutex_lock(&genl_mutex);
  28 }
  29
  30 static inline void genl_unlock(void)
  31 {
  32         mutex_unlock(&genl_mutex);
  33 }
  34
  35 #define GENL_FAM_TAB_SIZE       16
  36 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
  37
  38 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  39 /*
  40  * Bitmap of multicast groups that are currently in use.
  41  *
  42  * To avoid an allocation at boot of just one unsigned long,
  43  * declare it global instead.
  44  * Bit 0 is marked as already used since group 0 is invalid.
  45  */
  46 static unsigned long mc_group_start = 0x1;
  47 static unsigned long *mc_groups = &mc_group_start;
  48 static unsigned long mc_groups_longs = 1;
  49
  50 static int genl_ctrl_event(int event, void *data);
  51
  52 static inline unsigned int genl_family_hash(unsigned int id)
  53 {
  54         return id & GENL_FAM_TAB_MASK;
  55 }
  56
  57 static inline struct list_head *genl_family_chain(unsigned int id)
  58 {
  59         return &family_ht[genl_family_hash(id)];
  60 }
  61
  62 static struct genl_family *genl_family_find_byid(unsigned int id)
  63 {
  64         struct genl_family *f;
  65
  66         list_for_each_entry(f, genl_family_chain(id), family_list)
  67                 if (f->id == id)
  68                         return f;
  69
  70         return NULL;
  71 }
  72
  73 static struct genl_family *genl_family_find_byname(char *name)
  74 {
  75         struct genl_family *f;
  76         int i;
  77
  78         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
  79                 list_for_each_entry(f, genl_family_chain(i), family_list)
  80                         if (strcmp(f->name, name) == 0)
  81                                 return f;
  82
  83         return NULL;
  84 }
  85
  86 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
  87 {
  88         struct genl_ops *ops;
  89
  90         list_for_each_entry(ops, &family->ops_list, ops_list)
  91                 if (ops->cmd == cmd)
  92                         return ops;
  93
  94         return NULL;
  95 }
  96
  97 /* Of course we are going to have problems once we hit
  98  * 2^16 alive types, but that can only happen by year 2K
  99 */
 100 static inline u16 genl_generate_id(void)
 101 {
 102         static u16 id_gen_idx;
 103         int overflowed = 0;
 104
 105         do {
 106                 if (id_gen_idx == 0)
 107                         id_gen_idx = GENL_MIN_ID;
 108
 109                 if (++id_gen_idx > GENL_MAX_ID) {
 110                         if (!overflowed) {
 111                                 overflowed = 1;
 112                                 id_gen_idx = 0;
 113                                 continue;
 114                         } else
 115                                 return 0;
 116                 }
 117
 118         } while (genl_family_find_byid(id_gen_idx));
 119
 120         return id_gen_idx;
 121 }
 122
 123 static struct genl_multicast_group notify_grp;
 124
 125 /**
 126  * genl_register_mc_group - register a multicast group
 127  *
 128  * Registers the specified multicast group and notifies userspace
 129  * about the new group.
 130  *
 131  * Returns 0 on success or a negative error code.
 132  *
 133  * @family: The generic netlink family the group shall be registered for.
 134  * @grp: The group to register, must have a name.
 135  */
 136 int genl_register_mc_group(struct genl_family *family,
 137                            struct genl_multicast_group *grp)
 138 {
 139         int id;
 140         unsigned long *new_groups;
 141         int err;
 142
 143         BUG_ON(grp->name[0] == '\0');
 144
 145         genl_lock();
 146
 147         /* special-case our own group */
 148         if (grp == &notify_grp)
 149                 id = GENL_ID_CTRL;
 150         else
 151                 id = find_first_zero_bit(mc_groups,
 152                                          mc_groups_longs * BITS_PER_LONG);
 153
 154
 155         if (id >= mc_groups_longs * BITS_PER_LONG) {
 156                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
 157
 158                 if (mc_groups == &mc_group_start) {
 159                         new_groups = kzalloc(nlen, GFP_KERNEL);
 160                         if (!new_groups) {
 161                                 err = -ENOMEM;
 162                                 goto out;
 163                         }
 164                         mc_groups = new_groups;
 165                         *mc_groups = mc_group_start;
 166                 } else {
 167                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
 168                         if (!new_groups) {
 169                                 err = -ENOMEM;
 170                                 goto out;
 171                         }
 172                         mc_groups = new_groups;
 173                         mc_groups[mc_groups_longs] = 0;
 174                 }
 175                 mc_groups_longs++;
 176         }
 177
 178         err = netlink_change_ngroups(genl_sock,
 179                                      mc_groups_longs * BITS_PER_LONG);
 180         if (err)
 181                 goto out;
 182
 183         grp->id = id;
 184         set_bit(id, mc_groups);
 185         list_add_tail(&grp->list, &family->mcast_groups);
 186         grp->family = family;
 187
 188         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
 189  out:
 190         genl_unlock();
 191         return err;
 192 }
 193 EXPORT_SYMBOL(genl_register_mc_group);
 194
 195 static void __genl_unregister_mc_group(struct genl_family *family,
 196                                        struct genl_multicast_group *grp)
 197 {
 198         BUG_ON(grp->family != family);
 199         netlink_clear_multicast_users(genl_sock, grp->id);
 200         clear_bit(grp->id, mc_groups);
 201         list_del(&grp->list);
 202         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 203         grp->id = 0;
 204         grp->family = NULL;
 205 }
 206
 207 /**
 208  * genl_unregister_mc_group - unregister a multicast group
 209  *
 210  * Unregisters the specified multicast group and notifies userspace
 211  * about it. All current listeners on the group are removed.
 212  *
 213  * Note: It is not necessary to unregister all multicast groups before
 214  *       unregistering the family, unregistering the family will cause
 215  *       all assigned multicast groups to be unregistered automatically.
 216  *
 217  * @family: Generic netlink family the group belongs to.
 218  * @grp: The group to unregister, must have been registered successfully
 219  *       previously.
 220  */
 221 void genl_unregister_mc_group(struct genl_family *family,
 222                               struct genl_multicast_group *grp)
 223 {
 224         genl_lock();
 225         __genl_unregister_mc_group(family, grp);
 226         genl_unlock();
 227 }
 228
 229 static void genl_unregister_mc_groups(struct genl_family *family)
 230 {
 231         struct genl_multicast_group *grp, *tmp;
 232
 233         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 234                 __genl_unregister_mc_group(family, grp);
 235 }
 236
 237 /**
 238  * genl_register_ops - register generic netlink operations
 239  * @family: generic netlink family
 240  * @ops: operations to be registered
 241  *
 242  * Registers the specified operations and assigns them to the specified
 243  * family. Either a doit or dumpit callback must be specified or the
 244  * operation will fail. Only one operation structure per command
 245  * identifier may be registered.
 246  *
 247  * See include/net/genetlink.h for more documenation on the operations
 248  * structure.
 249  *
 250  * Returns 0 on success or a negative error code.
 251  */
 252 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 253 {
 254         int err = -EINVAL;
 255
 256         if (ops->dumpit == NULL && ops->doit == NULL)
 257                 goto errout;
 258
 259         if (genl_get_cmd(ops->cmd, family)) {
 260                 err = -EEXIST;
 261                 goto errout;
 262         }
 263
 264         if (ops->dumpit)
 265                 ops->flags |= GENL_CMD_CAP_DUMP;
 266         if (ops->doit)
 267                 ops->flags |= GENL_CMD_CAP_DO;
 268         if (ops->policy)
 269                 ops->flags |= GENL_CMD_CAP_HASPOL;
 270
 271         genl_lock();
 272         list_add_tail(&ops->ops_list, &family->ops_list);
 273         genl_unlock();
 274
 275         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 276         err = 0;
 277 errout:
 278         return err;
 279 }
 280
 281 /**
 282  * genl_unregister_ops - unregister generic netlink operations
 283  * @family: generic netlink family
 284  * @ops: operations to be unregistered
 285  *
 286  * Unregisters the specified operations and unassigns them from the
 287  * specified family. The operation blocks until the current message
 288  * processing has finished and doesn't start again until the
 289  * unregister process has finished.
 290  *
 291  * Note: It is not necessary to unregister all operations before
 292  *       unregistering the family, unregistering the family will cause
 293  *       all assigned operations to be unregistered automatically.
 294  *
 295  * Returns 0 on success or a negative error code.
 296  */
 297 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 298 {
 299         struct genl_ops *rc;
 300
 301         genl_lock();
 302         list_for_each_entry(rc, &family->ops_list, ops_list) {
 303                 if (rc == ops) {
 304                         list_del(&ops->ops_list);
 305                         genl_unlock();
 306                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
 307                         return 0;
 308                 }
 309         }
 310         genl_unlock();
 311
 312         return -ENOENT;
 313 }
 314
 315 /**
 316  * genl_register_family - register a generic netlink family
 317  * @family: generic netlink family
 318  *
 319  * Registers the specified family after validating it first. Only one
 320  * family may be registered with the same family name or identifier.
 321  * The family id may equal GENL_ID_GENERATE causing an unique id to
 322  * be automatically generated and assigned.
 323  *
 324  * Return 0 on success or a negative error code.
 325  */
 326 int genl_register_family(struct genl_family *family)
 327 {
 328         int err = -EINVAL;
 329
 330         if (family->id && family->id < GENL_MIN_ID)
 331                 goto errout;
 332
 333         if (family->id > GENL_MAX_ID)
 334                 goto errout;
 335
 336         INIT_LIST_HEAD(&family->ops_list);
 337         INIT_LIST_HEAD(&family->mcast_groups);
 338
 339         genl_lock();
 340
 341         if (genl_family_find_byname(family->name)) {
 342                 err = -EEXIST;
 343                 goto errout_locked;
 344         }
 345
 346         if (genl_family_find_byid(family->id)) {
 347                 err = -EEXIST;
 348                 goto errout_locked;
 349         }
 350
 351         if (family->id == GENL_ID_GENERATE) {
 352                 u16 newid = genl_generate_id();
 353
 354                 if (!newid) {
 355                         err = -ENOMEM;
 356                         goto errout_locked;
 357                 }
 358
 359                 family->id = newid;
 360         }
 361
 362         if (family->maxattr) {
 363                 family->attrbuf = kmalloc((family->maxattr+1) *
 364                                         sizeof(struct nlattr *), GFP_KERNEL);
 365                 if (family->attrbuf == NULL) {
 366                         err = -ENOMEM;
 367                         goto errout_locked;
 368                 }
 369         } else
 370                 family->attrbuf = NULL;
 371
 372         list_add_tail(&family->family_list, genl_family_chain(family->id));
 373         genl_unlock();
 374
 375         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 376
 377         return 0;
 378
 379 errout_locked:
 380         genl_unlock();
 381 errout:
 382         return err;
 383 }
 384
 385 /**
 386  * genl_unregister_family - unregister generic netlink family
 387  * @family: generic netlink family
 388  *
 389  * Unregisters the specified family.
 390  *
 391  * Returns 0 on success or a negative error code.
 392  */
 393 int genl_unregister_family(struct genl_family *family)
 394 {
 395         struct genl_family *rc;
 396
 397         genl_lock();
 398
 399         genl_unregister_mc_groups(family);
 400
 401         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 402                 if (family->id != rc->id || strcmp(rc->name, family->name))
 403                         continue;
 404
 405                 list_del(&rc->family_list);
 406                 INIT_LIST_HEAD(&family->ops_list);
 407                 genl_unlock();
 408
 409                 kfree(family->attrbuf);
 410                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 411                 return 0;
 412         }
 413
 414         genl_unlock();
 415
 416         return -ENOENT;
 417 }
 418
 419 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 420 {
 421         struct genl_ops *ops;
 422         struct genl_family *family;
 423         struct genl_info info;
 424         struct genlmsghdr *hdr = nlmsg_data(nlh);
 425         int hdrlen, err;
 426
 427         family = genl_family_find_byid(nlh->nlmsg_type);
 428         if (family == NULL)
 429                 return -ENOENT;
 430
 431         hdrlen = GENL_HDRLEN + family->hdrsize;
 432         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 433                 return -EINVAL;
 434
 435         ops = genl_get_cmd(hdr->cmd, family);
 436         if (ops == NULL)
 437                 return -EOPNOTSUPP;
 438
 439         if ((ops->flags & GENL_ADMIN_PERM) &&
 440             security_netlink_recv(skb, CAP_NET_ADMIN))
 441                 return -EPERM;
 442
 443         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 444                 if (ops->dumpit == NULL)
 445                         return -EOPNOTSUPP;
 446
 447                 genl_unlock();
 448                 err = netlink_dump_start(genl_sock, skb, nlh,
 449                                          ops->dumpit, ops->done);
 450                 genl_lock();
 451                 return err;
 452         }
 453
 454         if (ops->doit == NULL)
 455                 return -EOPNOTSUPP;
 456
 457         if (family->attrbuf) {
 458                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 459                                   ops->policy);
 460                 if (err < 0)
 461                         return err;
 462         }
 463
 464         info.snd_seq = nlh->nlmsg_seq;
 465         info.snd_pid = NETLINK_CB(skb).pid;
 466         info.nlhdr = nlh;
 467         info.genlhdr = nlmsg_data(nlh);
 468         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 469         info.attrs = family->attrbuf;
 470
 471         return ops->doit(skb, &info);
 472 }
 473
 474 static void genl_rcv(struct sk_buff *skb)
 475 {
 476         genl_lock();
 477         netlink_rcv_skb(skb, &genl_rcv_msg);
 478         genl_unlock();
 479 }
 480
 481 /**************************************************************************
 482  * Controller
 483  **************************************************************************/
 484
 485 static struct genl_family genl_ctrl = {
 486         .id = GENL_ID_CTRL,
 487         .name = "nlctrl",
 488         .version = 0x2,
 489         .maxattr = CTRL_ATTR_MAX,
 490 };
 491
 492 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 493                           u32 flags, struct sk_buff *skb, u8 cmd)
 494 {
 495         void *hdr;
 496
 497         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 498         if (hdr == NULL)
 499                 return -1;
 500
 501         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 502         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 503         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 504         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 505         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 506
 507         if (!list_empty(&family->ops_list)) {
 508                 struct nlattr *nla_ops;
 509                 struct genl_ops *ops;
 510                 int idx = 1;
 511
 512                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 513                 if (nla_ops == NULL)
 514                         goto nla_put_failure;
 515
 516                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 517                         struct nlattr *nest;
 518
 519                         nest = nla_nest_start(skb, idx++);
 520                         if (nest == NULL)
 521                                 goto nla_put_failure;
 522
 523                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 524                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 525
 526                         nla_nest_end(skb, nest);
 527                 }
 528
 529                 nla_nest_end(skb, nla_ops);
 530         }
 531
 532         if (!list_empty(&family->mcast_groups)) {
 533                 struct genl_multicast_group *grp;
 534                 struct nlattr *nla_grps;
 535                 int idx = 1;
 536
 537                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 538                 if (nla_grps == NULL)
 539                         goto nla_put_failure;
 540
 541                 list_for_each_entry(grp, &family->mcast_groups, list) {
 542                         struct nlattr *nest;
 543
 544                         nest = nla_nest_start(skb, idx++);
 545                         if (nest == NULL)
 546                                 goto nla_put_failure;
 547
 548                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 549                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 550                                        grp->name);
 551
 552                         nla_nest_end(skb, nest);
 553                 }
 554                 nla_nest_end(skb, nla_grps);
 555         }
 556
 557         return genlmsg_end(skb, hdr);
 558
 559 nla_put_failure:
 560         genlmsg_cancel(skb, hdr);
 561         return -EMSGSIZE;
 562 }
 563
 564 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 565                                 u32 seq, u32 flags, struct sk_buff *skb,
 566                                 u8 cmd)
 567 {
 568         void *hdr;
 569         struct nlattr *nla_grps;
 570         struct nlattr *nest;
 571
 572         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 573         if (hdr == NULL)
 574                 return -1;
 575
 576         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 577         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 578
 579         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 580         if (nla_grps == NULL)
 581                 goto nla_put_failure;
 582
 583         nest = nla_nest_start(skb, 1);
 584         if (nest == NULL)
 585                 goto nla_put_failure;
 586
 587         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 588         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 589                        grp->name);
 590
 591         nla_nest_end(skb, nest);
 592         nla_nest_end(skb, nla_grps);
 593
 594         return genlmsg_end(skb, hdr);
 595
 596 nla_put_failure:
 597         genlmsg_cancel(skb, hdr);
 598         return -EMSGSIZE;
 599 }
 600
 601 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 602 {
 603
 604         int i, n = 0;
 605         struct genl_family *rt;
 606         int chains_to_skip = cb->args[0];
 607         int fams_to_skip = cb->args[1];
 608
 609         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
 610                 if (i < chains_to_skip)
 611                         continue;
 612                 n = 0;
 613                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 614                         if (++n < fams_to_skip)
 615                                 continue;
 616                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
 617                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 618                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 619                                 goto errout;
 620                 }
 621
 622                 fams_to_skip = 0;
 623         }
 624
 625 errout:
 626         cb->args[0] = i;
 627         cb->args[1] = n;
 628
 629         return skb->len;
 630 }
 631
 632 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 633                                              u32 pid, int seq, u8 cmd)
 634 {
 635         struct sk_buff *skb;
 636         int err;
 637
 638         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 639         if (skb == NULL)
 640                 return ERR_PTR(-ENOBUFS);
 641
 642         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 643         if (err < 0) {
 644                 nlmsg_free(skb);
 645                 return ERR_PTR(err);
 646         }
 647
 648         return skb;
 649 }
 650
 651 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 652                                             u32 pid, int seq, u8 cmd)
 653 {
 654         struct sk_buff *skb;
 655         int err;
 656
 657         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 658         if (skb == NULL)
 659                 return ERR_PTR(-ENOBUFS);
 660
 661         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 662         if (err < 0) {
 663                 nlmsg_free(skb);
 664                 return ERR_PTR(err);
 665         }
 666
 667         return skb;
 668 }
 669
 670 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 671         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 672         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 673                                     .len = GENL_NAMSIZ - 1 },
 674 };
 675
 676 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 677 {
 678         struct sk_buff *msg;
 679         struct genl_family *res = NULL;
 680         int err = -EINVAL;
 681
 682         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 683                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 684                 res = genl_family_find_byid(id);
 685         }
 686
 687         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 688                 char *name;
 689
 690                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 691                 res = genl_family_find_byname(name);
 692         }
 693
 694         if (res == NULL) {
 695                 err = -ENOENT;
 696                 goto errout;
 697         }
 698
 699         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 700                                     CTRL_CMD_NEWFAMILY);
 701         if (IS_ERR(msg)) {
 702                 err = PTR_ERR(msg);
 703                 goto errout;
 704         }
 705
 706         err = genlmsg_reply(msg, info);
 707 errout:
 708         return err;
 709 }
 710
 711 static int genl_ctrl_event(int event, void *data)
 712 {
 713         struct sk_buff *msg;
 714
 715         if (genl_sock == NULL)
 716                 return 0;
 717
 718         switch (event) {
 719         case CTRL_CMD_NEWFAMILY:
 720         case CTRL_CMD_DELFAMILY:
 721                 msg = ctrl_build_family_msg(data, 0, 0, event);
 722                 if (IS_ERR(msg))
 723                         return PTR_ERR(msg);
 724
 725                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 726                 break;
 727         case CTRL_CMD_NEWMCAST_GRP:
 728         case CTRL_CMD_DELMCAST_GRP:
 729                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 730                 if (IS_ERR(msg))
 731                         return PTR_ERR(msg);
 732
 733                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 734                 break;
 735         }
 736
 737         return 0;
 738 }
 739
 740 static struct genl_ops genl_ctrl_ops = {
 741         .cmd            = CTRL_CMD_GETFAMILY,
 742         .doit           = ctrl_getfamily,
 743         .dumpit         = ctrl_dumpfamily,
 744         .policy         = ctrl_policy,
 745 };
 746
 747 static struct genl_multicast_group notify_grp = {
 748         .name           = "notify",
 749 };
 750
 751 static int __init genl_init(void)
 752 {
 753         int i, err;
 754
 755         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 756                 INIT_LIST_HEAD(&family_ht[i]);
 757
 758         err = genl_register_family(&genl_ctrl);
 759         if (err < 0)
 760                 goto errout;
 761
 762         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
 763         if (err < 0)
 764                 goto errout_register;
 765
 766         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 767
 768         /* we'll bump the group number right afterwards */
 769         genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
 770                                           genl_rcv, &genl_mutex, THIS_MODULE);
 771         if (genl_sock == NULL)
 772                 panic("GENL: Cannot initialize generic netlink\n");
 773
 774         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 775         if (err < 0)
 776                 goto errout_register;
 777
 778         return 0;
 779
 780 errout_register:
 781         genl_unregister_family(&genl_ctrl);
 782 errout:
 783         panic("GENL: Cannot register controller: %d\n", err);
 784 }
 785
 786 subsys_initcall(genl_init);
 787
 788 EXPORT_SYMBOL(genl_sock);
 789 EXPORT_SYMBOL(genl_register_ops);
 790 EXPORT_SYMBOL(genl_unregister_ops);
 791 EXPORT_SYMBOL(genl_register_family);
 792 EXPORT_SYMBOL(genl_unregister_family);