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   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 void genl_lock(void)
  26 {
  27         mutex_lock(&genl_mutex);
  28 }
  29
  30 static int genl_trylock(void)
  31 {
  32         return !mutex_trylock(&genl_mutex);
  33 }
  34
  35 static void genl_unlock(void)
  36 {
  37         mutex_unlock(&genl_mutex);
  38
  39         if (genl_sock && genl_sock->sk_receive_queue.qlen)
  40                 genl_sock->sk_data_ready(genl_sock, 0);
  41 }
  42
  43 #define GENL_FAM_TAB_SIZE       16
  44 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
  45
  46 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  47 /*
  48  * Bitmap of multicast groups that are currently in use.
  49  *
  50  * To avoid an allocation at boot of just one unsigned long,
  51  * declare it global instead.
  52  * Bit 0 is marked as already used since group 0 is invalid.
  53  */
  54 static unsigned long mc_group_start = 0x1;
  55 static unsigned long *mc_groups = &mc_group_start;
  56 static unsigned long mc_groups_longs = 1;
  57
  58 static int genl_ctrl_event(int event, void *data);
  59
  60 static inline unsigned int genl_family_hash(unsigned int id)
  61 {
  62         return id & GENL_FAM_TAB_MASK;
  63 }
  64
  65 static inline struct list_head *genl_family_chain(unsigned int id)
  66 {
  67         return &family_ht[genl_family_hash(id)];
  68 }
  69
  70 static struct genl_family *genl_family_find_byid(unsigned int id)
  71 {
  72         struct genl_family *f;
  73
  74         list_for_each_entry(f, genl_family_chain(id), family_list)
  75                 if (f->id == id)
  76                         return f;
  77
  78         return NULL;
  79 }
  80
  81 static struct genl_family *genl_family_find_byname(char *name)
  82 {
  83         struct genl_family *f;
  84         int i;
  85
  86         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
  87                 list_for_each_entry(f, genl_family_chain(i), family_list)
  88                         if (strcmp(f->name, name) == 0)
  89                                 return f;
  90
  91         return NULL;
  92 }
  93
  94 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
  95 {
  96         struct genl_ops *ops;
  97
  98         list_for_each_entry(ops, &family->ops_list, ops_list)
  99                 if (ops->cmd == cmd)
 100                         return ops;
 101
 102         return NULL;
 103 }
 104
 105 /* Of course we are going to have problems once we hit
 106  * 2^16 alive types, but that can only happen by year 2K
 107 */
 108 static inline u16 genl_generate_id(void)
 109 {
 110         static u16 id_gen_idx;
 111         int overflowed = 0;
 112
 113         do {
 114                 if (id_gen_idx == 0)
 115                         id_gen_idx = GENL_MIN_ID;
 116
 117                 if (++id_gen_idx > GENL_MAX_ID) {
 118                         if (!overflowed) {
 119                                 overflowed = 1;
 120                                 id_gen_idx = 0;
 121                                 continue;
 122                         } else
 123                                 return 0;
 124                 }
 125
 126         } while (genl_family_find_byid(id_gen_idx));
 127
 128         return id_gen_idx;
 129 }
 130
 131 static struct genl_multicast_group notify_grp;
 132
 133 /**
 134  * genl_register_mc_group - register a multicast group
 135  *
 136  * Registers the specified multicast group and notifies userspace
 137  * about the new group.
 138  *
 139  * Returns 0 on success or a negative error code.
 140  *
 141  * @family: The generic netlink family the group shall be registered for.
 142  * @grp: The group to register, must have a name.
 143  */
 144 int genl_register_mc_group(struct genl_family *family,
 145                            struct genl_multicast_group *grp)
 146 {
 147         int id;
 148         unsigned long *new_groups;
 149         int err;
 150
 151         BUG_ON(grp->name[0] == '\0');
 152
 153         genl_lock();
 154
 155         /* special-case our own group */
 156         if (grp == &notify_grp)
 157                 id = GENL_ID_CTRL;
 158         else
 159                 id = find_first_zero_bit(mc_groups,
 160                                          mc_groups_longs * BITS_PER_LONG);
 161
 162
 163         if (id >= mc_groups_longs * BITS_PER_LONG) {
 164                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
 165
 166                 if (mc_groups == &mc_group_start) {
 167                         new_groups = kzalloc(nlen, GFP_KERNEL);
 168                         if (!new_groups) {
 169                                 err = -ENOMEM;
 170                                 goto out;
 171                         }
 172                         mc_groups = new_groups;
 173                         *mc_groups = mc_group_start;
 174                 } else {
 175                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
 176                         if (!new_groups) {
 177                                 err = -ENOMEM;
 178                                 goto out;
 179                         }
 180                         mc_groups = new_groups;
 181                         mc_groups[mc_groups_longs] = 0;
 182                 }
 183                 mc_groups_longs++;
 184         }
 185
 186         err = netlink_change_ngroups(genl_sock,
 187                                      mc_groups_longs * BITS_PER_LONG);
 188         if (err)
 189                 goto out;
 190
 191         grp->id = id;
 192         set_bit(id, mc_groups);
 193         list_add_tail(&grp->list, &family->mcast_groups);
 194         grp->family = family;
 195
 196         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
 197  out:
 198         genl_unlock();
 199         return err;
 200 }
 201 EXPORT_SYMBOL(genl_register_mc_group);
 202
 203 static void __genl_unregister_mc_group(struct genl_family *family,
 204                                        struct genl_multicast_group *grp)
 205 {
 206         BUG_ON(grp->family != family);
 207         netlink_clear_multicast_users(genl_sock, grp->id);
 208         clear_bit(grp->id, mc_groups);
 209         list_del(&grp->list);
 210         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 211         grp->id = 0;
 212         grp->family = NULL;
 213 }
 214
 215 /**
 216  * genl_unregister_mc_group - unregister a multicast group
 217  *
 218  * Unregisters the specified multicast group and notifies userspace
 219  * about it. All current listeners on the group are removed.
 220  *
 221  * Note: It is not necessary to unregister all multicast groups before
 222  *       unregistering the family, unregistering the family will cause
 223  *       all assigned multicast groups to be unregistered automatically.
 224  *
 225  * @family: Generic netlink family the group belongs to.
 226  * @grp: The group to unregister, must have been registered successfully
 227  *       previously.
 228  */
 229 void genl_unregister_mc_group(struct genl_family *family,
 230                               struct genl_multicast_group *grp)
 231 {
 232         genl_lock();
 233         __genl_unregister_mc_group(family, grp);
 234         genl_unlock();
 235 }
 236
 237 static void genl_unregister_mc_groups(struct genl_family *family)
 238 {
 239         struct genl_multicast_group *grp, *tmp;
 240
 241         genl_lock();
 242         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 243                 __genl_unregister_mc_group(family, grp);
 244         genl_unlock();
 245 }
 246
 247 /**
 248  * genl_register_ops - register generic netlink operations
 249  * @family: generic netlink family
 250  * @ops: operations to be registered
 251  *
 252  * Registers the specified operations and assigns them to the specified
 253  * family. Either a doit or dumpit callback must be specified or the
 254  * operation will fail. Only one operation structure per command
 255  * identifier may be registered.
 256  *
 257  * See include/net/genetlink.h for more documenation on the operations
 258  * structure.
 259  *
 260  * Returns 0 on success or a negative error code.
 261  */
 262 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 263 {
 264         int err = -EINVAL;
 265
 266         if (ops->dumpit == NULL && ops->doit == NULL)
 267                 goto errout;
 268
 269         if (genl_get_cmd(ops->cmd, family)) {
 270                 err = -EEXIST;
 271                 goto errout;
 272         }
 273
 274         if (ops->dumpit)
 275                 ops->flags |= GENL_CMD_CAP_DUMP;
 276         if (ops->doit)
 277                 ops->flags |= GENL_CMD_CAP_DO;
 278         if (ops->policy)
 279                 ops->flags |= GENL_CMD_CAP_HASPOL;
 280
 281         genl_lock();
 282         list_add_tail(&ops->ops_list, &family->ops_list);
 283         genl_unlock();
 284
 285         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 286         err = 0;
 287 errout:
 288         return err;
 289 }
 290
 291 /**
 292  * genl_unregister_ops - unregister generic netlink operations
 293  * @family: generic netlink family
 294  * @ops: operations to be unregistered
 295  *
 296  * Unregisters the specified operations and unassigns them from the
 297  * specified family. The operation blocks until the current message
 298  * processing has finished and doesn't start again until the
 299  * unregister process has finished.
 300  *
 301  * Note: It is not necessary to unregister all operations before
 302  *       unregistering the family, unregistering the family will cause
 303  *       all assigned operations to be unregistered automatically.
 304  *
 305  * Returns 0 on success or a negative error code.
 306  */
 307 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 308 {
 309         struct genl_ops *rc;
 310
 311         genl_lock();
 312         list_for_each_entry(rc, &family->ops_list, ops_list) {
 313                 if (rc == ops) {
 314                         list_del(&ops->ops_list);
 315                         genl_unlock();
 316                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
 317                         return 0;
 318                 }
 319         }
 320         genl_unlock();
 321
 322         return -ENOENT;
 323 }
 324
 325 /**
 326  * genl_register_family - register a generic netlink family
 327  * @family: generic netlink family
 328  *
 329  * Registers the specified family after validating it first. Only one
 330  * family may be registered with the same family name or identifier.
 331  * The family id may equal GENL_ID_GENERATE causing an unique id to
 332  * be automatically generated and assigned.
 333  *
 334  * Return 0 on success or a negative error code.
 335  */
 336 int genl_register_family(struct genl_family *family)
 337 {
 338         int err = -EINVAL;
 339
 340         if (family->id && family->id < GENL_MIN_ID)
 341                 goto errout;
 342
 343         if (family->id > GENL_MAX_ID)
 344                 goto errout;
 345
 346         INIT_LIST_HEAD(&family->ops_list);
 347         INIT_LIST_HEAD(&family->mcast_groups);
 348
 349         genl_lock();
 350
 351         if (genl_family_find_byname(family->name)) {
 352                 err = -EEXIST;
 353                 goto errout_locked;
 354         }
 355
 356         if (genl_family_find_byid(family->id)) {
 357                 err = -EEXIST;
 358                 goto errout_locked;
 359         }
 360
 361         if (family->id == GENL_ID_GENERATE) {
 362                 u16 newid = genl_generate_id();
 363
 364                 if (!newid) {
 365                         err = -ENOMEM;
 366                         goto errout_locked;
 367                 }
 368
 369                 family->id = newid;
 370         }
 371
 372         if (family->maxattr) {
 373                 family->attrbuf = kmalloc((family->maxattr+1) *
 374                                         sizeof(struct nlattr *), GFP_KERNEL);
 375                 if (family->attrbuf == NULL) {
 376                         err = -ENOMEM;
 377                         goto errout_locked;
 378                 }
 379         } else
 380                 family->attrbuf = NULL;
 381
 382         list_add_tail(&family->family_list, genl_family_chain(family->id));
 383         genl_unlock();
 384
 385         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 386
 387         return 0;
 388
 389 errout_locked:
 390         genl_unlock();
 391 errout:
 392         return err;
 393 }
 394
 395 /**
 396  * genl_unregister_family - unregister generic netlink family
 397  * @family: generic netlink family
 398  *
 399  * Unregisters the specified family.
 400  *
 401  * Returns 0 on success or a negative error code.
 402  */
 403 int genl_unregister_family(struct genl_family *family)
 404 {
 405         struct genl_family *rc;
 406
 407         genl_unregister_mc_groups(family);
 408
 409         genl_lock();
 410
 411         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 412                 if (family->id != rc->id || strcmp(rc->name, family->name))
 413                         continue;
 414
 415                 list_del(&rc->family_list);
 416                 INIT_LIST_HEAD(&family->ops_list);
 417                 genl_unlock();
 418
 419                 kfree(family->attrbuf);
 420                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 421                 return 0;
 422         }
 423
 424         genl_unlock();
 425
 426         return -ENOENT;
 427 }
 428
 429 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 430 {
 431         struct genl_ops *ops;
 432         struct genl_family *family;
 433         struct genl_info info;
 434         struct genlmsghdr *hdr = nlmsg_data(nlh);
 435         int hdrlen, err;
 436
 437         family = genl_family_find_byid(nlh->nlmsg_type);
 438         if (family == NULL)
 439                 return -ENOENT;
 440
 441         hdrlen = GENL_HDRLEN + family->hdrsize;
 442         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 443                 return -EINVAL;
 444
 445         ops = genl_get_cmd(hdr->cmd, family);
 446         if (ops == NULL)
 447                 return -EOPNOTSUPP;
 448
 449         if ((ops->flags & GENL_ADMIN_PERM) &&
 450             security_netlink_recv(skb, CAP_NET_ADMIN))
 451                 return -EPERM;
 452
 453         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 454                 if (ops->dumpit == NULL)
 455                         return -EOPNOTSUPP;
 456
 457                 return netlink_dump_start(genl_sock, skb, nlh,
 458                                           ops->dumpit, ops->done);
 459         }
 460
 461         if (ops->doit == NULL)
 462                 return -EOPNOTSUPP;
 463
 464         if (family->attrbuf) {
 465                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 466                                   ops->policy);
 467                 if (err < 0)
 468                         return err;
 469         }
 470
 471         info.snd_seq = nlh->nlmsg_seq;
 472         info.snd_pid = NETLINK_CB(skb).pid;
 473         info.nlhdr = nlh;
 474         info.genlhdr = nlmsg_data(nlh);
 475         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 476         info.attrs = family->attrbuf;
 477
 478         return ops->doit(skb, &info);
 479 }
 480
 481 static void genl_rcv(struct sock *sk, int len)
 482 {
 483         unsigned int qlen = 0;
 484
 485         do {
 486                 if (genl_trylock())
 487                         return;
 488                 netlink_run_queue(sk, &qlen, genl_rcv_msg);
 489                 genl_unlock();
 490         } while (qlen && genl_sock && genl_sock->sk_receive_queue.qlen);
 491 }
 492
 493 /**************************************************************************
 494  * Controller
 495  **************************************************************************/
 496
 497 static struct genl_family genl_ctrl = {
 498         .id = GENL_ID_CTRL,
 499         .name = "nlctrl",
 500         .version = 0x2,
 501         .maxattr = CTRL_ATTR_MAX,
 502 };
 503
 504 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 505                           u32 flags, struct sk_buff *skb, u8 cmd)
 506 {
 507         void *hdr;
 508
 509         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 510         if (hdr == NULL)
 511                 return -1;
 512
 513         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 514         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 515         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 516         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 517         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 518
 519         if (!list_empty(&family->ops_list)) {
 520                 struct nlattr *nla_ops;
 521                 struct genl_ops *ops;
 522                 int idx = 1;
 523
 524                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 525                 if (nla_ops == NULL)
 526                         goto nla_put_failure;
 527
 528                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 529                         struct nlattr *nest;
 530
 531                         nest = nla_nest_start(skb, idx++);
 532                         if (nest == NULL)
 533                                 goto nla_put_failure;
 534
 535                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 536                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 537
 538                         nla_nest_end(skb, nest);
 539                 }
 540
 541                 nla_nest_end(skb, nla_ops);
 542         }
 543
 544         if (!list_empty(&family->mcast_groups)) {
 545                 struct genl_multicast_group *grp;
 546                 struct nlattr *nla_grps;
 547                 int idx = 1;
 548
 549                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 550                 if (nla_grps == NULL)
 551                         goto nla_put_failure;
 552
 553                 list_for_each_entry(grp, &family->mcast_groups, list) {
 554                         struct nlattr *nest;
 555
 556                         nest = nla_nest_start(skb, idx++);
 557                         if (nest == NULL)
 558                                 goto nla_put_failure;
 559
 560                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 561                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 562                                        grp->name);
 563
 564                         nla_nest_end(skb, nest);
 565                 }
 566                 nla_nest_end(skb, nla_grps);
 567         }
 568
 569         return genlmsg_end(skb, hdr);
 570
 571 nla_put_failure:
 572         return genlmsg_cancel(skb, hdr);
 573 }
 574
 575 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 576                                 u32 seq, u32 flags, struct sk_buff *skb,
 577                                 u8 cmd)
 578 {
 579         void *hdr;
 580         struct nlattr *nla_grps;
 581         struct nlattr *nest;
 582
 583         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 584         if (hdr == NULL)
 585                 return -1;
 586
 587         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 588         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 589
 590         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 591         if (nla_grps == NULL)
 592                 goto nla_put_failure;
 593
 594         nest = nla_nest_start(skb, 1);
 595         if (nest == NULL)
 596                 goto nla_put_failure;
 597
 598         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 599         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 600                        grp->name);
 601
 602         nla_nest_end(skb, nest);
 603         nla_nest_end(skb, nla_grps);
 604
 605         return genlmsg_end(skb, hdr);
 606
 607 nla_put_failure:
 608         return genlmsg_cancel(skb, hdr);
 609 }
 610
 611 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 612 {
 613
 614         int i, n = 0;
 615         struct genl_family *rt;
 616         int chains_to_skip = cb->args[0];
 617         int fams_to_skip = cb->args[1];
 618
 619         if (chains_to_skip != 0)
 620                 genl_lock();
 621
 622         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
 623                 if (i < chains_to_skip)
 624                         continue;
 625                 n = 0;
 626                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 627                         if (++n < fams_to_skip)
 628                                 continue;
 629                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
 630                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 631                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 632                                 goto errout;
 633                 }
 634
 635                 fams_to_skip = 0;
 636         }
 637
 638 errout:
 639         if (chains_to_skip != 0)
 640                 genl_unlock();
 641
 642         cb->args[0] = i;
 643         cb->args[1] = n;
 644
 645         return skb->len;
 646 }
 647
 648 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 649                                              u32 pid, int seq, u8 cmd)
 650 {
 651         struct sk_buff *skb;
 652         int err;
 653
 654         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 655         if (skb == NULL)
 656                 return ERR_PTR(-ENOBUFS);
 657
 658         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 659         if (err < 0) {
 660                 nlmsg_free(skb);
 661                 return ERR_PTR(err);
 662         }
 663
 664         return skb;
 665 }
 666
 667 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 668                                             u32 pid, int seq, u8 cmd)
 669 {
 670         struct sk_buff *skb;
 671         int err;
 672
 673         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 674         if (skb == NULL)
 675                 return ERR_PTR(-ENOBUFS);
 676
 677         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 678         if (err < 0) {
 679                 nlmsg_free(skb);
 680                 return ERR_PTR(err);
 681         }
 682
 683         return skb;
 684 }
 685
 686 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 687         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 688         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 689                                     .len = GENL_NAMSIZ - 1 },
 690 };
 691
 692 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 693 {
 694         struct sk_buff *msg;
 695         struct genl_family *res = NULL;
 696         int err = -EINVAL;
 697
 698         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 699                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 700                 res = genl_family_find_byid(id);
 701         }
 702
 703         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 704                 char *name;
 705
 706                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 707                 res = genl_family_find_byname(name);
 708         }
 709
 710         if (res == NULL) {
 711                 err = -ENOENT;
 712                 goto errout;
 713         }
 714
 715         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 716                                     CTRL_CMD_NEWFAMILY);
 717         if (IS_ERR(msg)) {
 718                 err = PTR_ERR(msg);
 719                 goto errout;
 720         }
 721
 722         err = genlmsg_reply(msg, info);
 723 errout:
 724         return err;
 725 }
 726
 727 static int genl_ctrl_event(int event, void *data)
 728 {
 729         struct sk_buff *msg;
 730
 731         if (genl_sock == NULL)
 732                 return 0;
 733
 734         switch (event) {
 735         case CTRL_CMD_NEWFAMILY:
 736         case CTRL_CMD_DELFAMILY:
 737                 msg = ctrl_build_family_msg(data, 0, 0, event);
 738                 if (IS_ERR(msg))
 739                         return PTR_ERR(msg);
 740
 741                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 742                 break;
 743         case CTRL_CMD_NEWMCAST_GRP:
 744         case CTRL_CMD_DELMCAST_GRP:
 745                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 746                 if (IS_ERR(msg))
 747                         return PTR_ERR(msg);
 748
 749                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 750                 break;
 751         }
 752
 753         return 0;
 754 }
 755
 756 static struct genl_ops genl_ctrl_ops = {
 757         .cmd            = CTRL_CMD_GETFAMILY,
 758         .doit           = ctrl_getfamily,
 759         .dumpit         = ctrl_dumpfamily,
 760         .policy         = ctrl_policy,
 761 };
 762
 763 static struct genl_multicast_group notify_grp = {
 764         .name           = "notify",
 765 };
 766
 767 static int __init genl_init(void)
 768 {
 769         int i, err;
 770
 771         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 772                 INIT_LIST_HEAD(&family_ht[i]);
 773
 774         err = genl_register_family(&genl_ctrl);
 775         if (err < 0)
 776                 goto errout;
 777
 778         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
 779         if (err < 0)
 780                 goto errout_register;
 781
 782         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 783
 784         /* we'll bump the group number right afterwards */
 785         genl_sock = netlink_kernel_create(NETLINK_GENERIC, 0, genl_rcv,
 786                                           NULL, THIS_MODULE);
 787         if (genl_sock == NULL)
 788                 panic("GENL: Cannot initialize generic netlink\n");
 789
 790         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 791         if (err < 0)
 792                 goto errout_register;
 793
 794         return 0;
 795
 796 errout_register:
 797         genl_unregister_family(&genl_ctrl);
 798 errout:
 799         panic("GENL: Cannot register controller: %d\n", err);
 800 }
 801
 802 subsys_initcall(genl_init);
 803
 804 EXPORT_SYMBOL(genl_sock);
 805 EXPORT_SYMBOL(genl_register_ops);
 806 EXPORT_SYMBOL(genl_unregister_ops);
 807 EXPORT_SYMBOL(genl_register_family);
 808 EXPORT_SYMBOL(genl_unregister_family);