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 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                                      sizeof(unsigned long) * NETLINK_GENERIC);
 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 0;
 200 }
 201 EXPORT_SYMBOL(genl_register_mc_group);
 202
 203 /**
 204  * genl_unregister_mc_group - unregister a multicast group
 205  *
 206  * Unregisters the specified multicast group and notifies userspace
 207  * about it. All current listeners on the group are removed.
 208  *
 209  * Note: It is not necessary to unregister all multicast groups before
 210  *       unregistering the family, unregistering the family will cause
 211  *       all assigned multicast groups to be unregistered automatically.
 212  *
 213  * @family: Generic netlink family the group belongs to.
 214  * @grp: The group to unregister, must have been registered successfully
 215  *       previously.
 216  */
 217 void genl_unregister_mc_group(struct genl_family *family,
 218                               struct genl_multicast_group *grp)
 219 {
 220         BUG_ON(grp->family != family);
 221         genl_lock();
 222         netlink_clear_multicast_users(genl_sock, grp->id);
 223         clear_bit(grp->id, mc_groups);
 224         list_del(&grp->list);
 225         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 226         grp->id = 0;
 227         grp->family = NULL;
 228         genl_unlock();
 229 }
 230
 231 static void genl_unregister_mc_groups(struct genl_family *family)
 232 {
 233         struct genl_multicast_group *grp, *tmp;
 234
 235         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 236                 genl_unregister_mc_group(family, grp);
 237 }
 238
 239 /**
 240  * genl_register_ops - register generic netlink operations
 241  * @family: generic netlink family
 242  * @ops: operations to be registered
 243  *
 244  * Registers the specified operations and assigns them to the specified
 245  * family. Either a doit or dumpit callback must be specified or the
 246  * operation will fail. Only one operation structure per command
 247  * identifier may be registered.
 248  *
 249  * See include/net/genetlink.h for more documenation on the operations
 250  * structure.
 251  *
 252  * Returns 0 on success or a negative error code.
 253  */
 254 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 255 {
 256         int err = -EINVAL;
 257
 258         if (ops->dumpit == NULL && ops->doit == NULL)
 259                 goto errout;
 260
 261         if (genl_get_cmd(ops->cmd, family)) {
 262                 err = -EEXIST;
 263                 goto errout;
 264         }
 265
 266         if (ops->dumpit)
 267                 ops->flags |= GENL_CMD_CAP_DUMP;
 268         if (ops->doit)
 269                 ops->flags |= GENL_CMD_CAP_DO;
 270         if (ops->policy)
 271                 ops->flags |= GENL_CMD_CAP_HASPOL;
 272
 273         genl_lock();
 274         list_add_tail(&ops->ops_list, &family->ops_list);
 275         genl_unlock();
 276
 277         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 278         err = 0;
 279 errout:
 280         return err;
 281 }
 282
 283 /**
 284  * genl_unregister_ops - unregister generic netlink operations
 285  * @family: generic netlink family
 286  * @ops: operations to be unregistered
 287  *
 288  * Unregisters the specified operations and unassigns them from the
 289  * specified family. The operation blocks until the current message
 290  * processing has finished and doesn't start again until the
 291  * unregister process has finished.
 292  *
 293  * Note: It is not necessary to unregister all operations before
 294  *       unregistering the family, unregistering the family will cause
 295  *       all assigned operations to be unregistered automatically.
 296  *
 297  * Returns 0 on success or a negative error code.
 298  */
 299 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 300 {
 301         struct genl_ops *rc;
 302
 303         genl_lock();
 304         list_for_each_entry(rc, &family->ops_list, ops_list) {
 305                 if (rc == ops) {
 306                         list_del(&ops->ops_list);
 307                         genl_unlock();
 308                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
 309                         return 0;
 310                 }
 311         }
 312         genl_unlock();
 313
 314         return -ENOENT;
 315 }
 316
 317 /**
 318  * genl_register_family - register a generic netlink family
 319  * @family: generic netlink family
 320  *
 321  * Registers the specified family after validating it first. Only one
 322  * family may be registered with the same family name or identifier.
 323  * The family id may equal GENL_ID_GENERATE causing an unique id to
 324  * be automatically generated and assigned.
 325  *
 326  * Return 0 on success or a negative error code.
 327  */
 328 int genl_register_family(struct genl_family *family)
 329 {
 330         int err = -EINVAL;
 331
 332         if (family->id && family->id < GENL_MIN_ID)
 333                 goto errout;
 334
 335         if (family->id > GENL_MAX_ID)
 336                 goto errout;
 337
 338         INIT_LIST_HEAD(&family->ops_list);
 339         INIT_LIST_HEAD(&family->mcast_groups);
 340
 341         genl_lock();
 342
 343         if (genl_family_find_byname(family->name)) {
 344                 err = -EEXIST;
 345                 goto errout_locked;
 346         }
 347
 348         if (genl_family_find_byid(family->id)) {
 349                 err = -EEXIST;
 350                 goto errout_locked;
 351         }
 352
 353         if (family->id == GENL_ID_GENERATE) {
 354                 u16 newid = genl_generate_id();
 355
 356                 if (!newid) {
 357                         err = -ENOMEM;
 358                         goto errout_locked;
 359                 }
 360
 361                 family->id = newid;
 362         }
 363
 364         if (family->maxattr) {
 365                 family->attrbuf = kmalloc((family->maxattr+1) *
 366                                         sizeof(struct nlattr *), GFP_KERNEL);
 367                 if (family->attrbuf == NULL) {
 368                         err = -ENOMEM;
 369                         goto errout_locked;
 370                 }
 371         } else
 372                 family->attrbuf = NULL;
 373
 374         list_add_tail(&family->family_list, genl_family_chain(family->id));
 375         genl_unlock();
 376
 377         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 378
 379         return 0;
 380
 381 errout_locked:
 382         genl_unlock();
 383 errout:
 384         return err;
 385 }
 386
 387 /**
 388  * genl_unregister_family - unregister generic netlink family
 389  * @family: generic netlink family
 390  *
 391  * Unregisters the specified family.
 392  *
 393  * Returns 0 on success or a negative error code.
 394  */
 395 int genl_unregister_family(struct genl_family *family)
 396 {
 397         struct genl_family *rc;
 398
 399         genl_unregister_mc_groups(family);
 400
 401         genl_lock();
 402
 403         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 404                 if (family->id != rc->id || strcmp(rc->name, family->name))
 405                         continue;
 406
 407                 list_del(&rc->family_list);
 408                 INIT_LIST_HEAD(&family->ops_list);
 409                 genl_unlock();
 410
 411                 kfree(family->attrbuf);
 412                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 413                 return 0;
 414         }
 415
 416         genl_unlock();
 417
 418         return -ENOENT;
 419 }
 420
 421 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 422 {
 423         struct genl_ops *ops;
 424         struct genl_family *family;
 425         struct genl_info info;
 426         struct genlmsghdr *hdr = nlmsg_data(nlh);
 427         int hdrlen, err;
 428
 429         family = genl_family_find_byid(nlh->nlmsg_type);
 430         if (family == NULL)
 431                 return -ENOENT;
 432
 433         hdrlen = GENL_HDRLEN + family->hdrsize;
 434         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 435                 return -EINVAL;
 436
 437         ops = genl_get_cmd(hdr->cmd, family);
 438         if (ops == NULL)
 439                 return -EOPNOTSUPP;
 440
 441         if ((ops->flags & GENL_ADMIN_PERM) &&
 442             security_netlink_recv(skb, CAP_NET_ADMIN))
 443                 return -EPERM;
 444
 445         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 446                 if (ops->dumpit == NULL)
 447                         return -EOPNOTSUPP;
 448
 449                 return netlink_dump_start(genl_sock, skb, nlh,
 450                                           ops->dumpit, ops->done);
 451         }
 452
 453         if (ops->doit == NULL)
 454                 return -EOPNOTSUPP;
 455
 456         if (family->attrbuf) {
 457                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 458                                   ops->policy);
 459                 if (err < 0)
 460                         return err;
 461         }
 462
 463         info.snd_seq = nlh->nlmsg_seq;
 464         info.snd_pid = NETLINK_CB(skb).pid;
 465         info.nlhdr = nlh;
 466         info.genlhdr = nlmsg_data(nlh);
 467         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 468         info.attrs = family->attrbuf;
 469
 470         return ops->doit(skb, &info);
 471 }
 472
 473 static void genl_rcv(struct sock *sk, int len)
 474 {
 475         unsigned int qlen = 0;
 476
 477         do {
 478                 if (genl_trylock())
 479                         return;
 480                 netlink_run_queue(sk, &qlen, genl_rcv_msg);
 481                 genl_unlock();
 482         } while (qlen && genl_sock && genl_sock->sk_receive_queue.qlen);
 483 }
 484
 485 /**************************************************************************
 486  * Controller
 487  **************************************************************************/
 488
 489 static struct genl_family genl_ctrl = {
 490         .id = GENL_ID_CTRL,
 491         .name = "nlctrl",
 492         .version = 0x2,
 493         .maxattr = CTRL_ATTR_MAX,
 494 };
 495
 496 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 497                           u32 flags, struct sk_buff *skb, u8 cmd)
 498 {
 499         void *hdr;
 500
 501         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 502         if (hdr == NULL)
 503                 return -1;
 504
 505         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 506         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 507         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 508         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 509         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 510
 511         if (!list_empty(&family->ops_list)) {
 512                 struct nlattr *nla_ops;
 513                 struct genl_ops *ops;
 514                 int idx = 1;
 515
 516                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 517                 if (nla_ops == NULL)
 518                         goto nla_put_failure;
 519
 520                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 521                         struct nlattr *nest;
 522
 523                         nest = nla_nest_start(skb, idx++);
 524                         if (nest == NULL)
 525                                 goto nla_put_failure;
 526
 527                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 528                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 529
 530                         nla_nest_end(skb, nest);
 531                 }
 532
 533                 nla_nest_end(skb, nla_ops);
 534         }
 535
 536         if (!list_empty(&family->mcast_groups)) {
 537                 struct genl_multicast_group *grp;
 538                 struct nlattr *nla_grps;
 539                 int idx = 1;
 540
 541                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 542                 if (nla_grps == NULL)
 543                         goto nla_put_failure;
 544
 545                 list_for_each_entry(grp, &family->mcast_groups, list) {
 546                         struct nlattr *nest;
 547
 548                         nest = nla_nest_start(skb, idx++);
 549                         if (nest == NULL)
 550                                 goto nla_put_failure;
 551
 552                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 553                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 554                                        grp->name);
 555
 556                         nla_nest_end(skb, nest);
 557                 }
 558                 nla_nest_end(skb, nla_grps);
 559         }
 560
 561         return genlmsg_end(skb, hdr);
 562
 563 nla_put_failure:
 564         return genlmsg_cancel(skb, hdr);
 565 }
 566
 567 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 568                                 u32 seq, u32 flags, struct sk_buff *skb,
 569                                 u8 cmd)
 570 {
 571         void *hdr;
 572         struct nlattr *nla_grps;
 573         struct nlattr *nest;
 574
 575         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 576         if (hdr == NULL)
 577                 return -1;
 578
 579         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 580         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 581
 582         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 583         if (nla_grps == NULL)
 584                 goto nla_put_failure;
 585
 586         nest = nla_nest_start(skb, 1);
 587         if (nest == NULL)
 588                 goto nla_put_failure;
 589
 590         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 591         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 592                        grp->name);
 593
 594         nla_nest_end(skb, nest);
 595         nla_nest_end(skb, nla_grps);
 596
 597         return genlmsg_end(skb, hdr);
 598
 599 nla_put_failure:
 600         return genlmsg_cancel(skb, hdr);
 601 }
 602
 603 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 604 {
 605
 606         int i, n = 0;
 607         struct genl_family *rt;
 608         int chains_to_skip = cb->args[0];
 609         int fams_to_skip = cb->args[1];
 610
 611         if (chains_to_skip != 0)
 612                 genl_lock();
 613
 614         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
 615                 if (i < chains_to_skip)
 616                         continue;
 617                 n = 0;
 618                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 619                         if (++n < fams_to_skip)
 620                                 continue;
 621                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
 622                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 623                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 624                                 goto errout;
 625                 }
 626
 627                 fams_to_skip = 0;
 628         }
 629
 630 errout:
 631         if (chains_to_skip != 0)
 632                 genl_unlock();
 633
 634         cb->args[0] = i;
 635         cb->args[1] = n;
 636
 637         return skb->len;
 638 }
 639
 640 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 641                                              u32 pid, int seq, u8 cmd)
 642 {
 643         struct sk_buff *skb;
 644         int err;
 645
 646         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 647         if (skb == NULL)
 648                 return ERR_PTR(-ENOBUFS);
 649
 650         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 651         if (err < 0) {
 652                 nlmsg_free(skb);
 653                 return ERR_PTR(err);
 654         }
 655
 656         return skb;
 657 }
 658
 659 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 660                                             u32 pid, int seq, u8 cmd)
 661 {
 662         struct sk_buff *skb;
 663         int err;
 664
 665         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 666         if (skb == NULL)
 667                 return ERR_PTR(-ENOBUFS);
 668
 669         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 670         if (err < 0) {
 671                 nlmsg_free(skb);
 672                 return ERR_PTR(err);
 673         }
 674
 675         return skb;
 676 }
 677
 678 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 679         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 680         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 681                                     .len = GENL_NAMSIZ - 1 },
 682 };
 683
 684 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 685 {
 686         struct sk_buff *msg;
 687         struct genl_family *res = NULL;
 688         int err = -EINVAL;
 689
 690         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 691                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 692                 res = genl_family_find_byid(id);
 693         }
 694
 695         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 696                 char *name;
 697
 698                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 699                 res = genl_family_find_byname(name);
 700         }
 701
 702         if (res == NULL) {
 703                 err = -ENOENT;
 704                 goto errout;
 705         }
 706
 707         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 708                                     CTRL_CMD_NEWFAMILY);
 709         if (IS_ERR(msg)) {
 710                 err = PTR_ERR(msg);
 711                 goto errout;
 712         }
 713
 714         err = genlmsg_reply(msg, info);
 715 errout:
 716         return err;
 717 }
 718
 719 static int genl_ctrl_event(int event, void *data)
 720 {
 721         struct sk_buff *msg;
 722
 723         if (genl_sock == NULL)
 724                 return 0;
 725
 726         switch (event) {
 727         case CTRL_CMD_NEWFAMILY:
 728         case CTRL_CMD_DELFAMILY:
 729                 msg = ctrl_build_family_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         case CTRL_CMD_NEWMCAST_GRP:
 736         case CTRL_CMD_DELMCAST_GRP:
 737                 msg = ctrl_build_mcgrp_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         }
 744
 745         return 0;
 746 }
 747
 748 static struct genl_ops genl_ctrl_ops = {
 749         .cmd            = CTRL_CMD_GETFAMILY,
 750         .doit           = ctrl_getfamily,
 751         .dumpit         = ctrl_dumpfamily,
 752         .policy         = ctrl_policy,
 753 };
 754
 755 static struct genl_multicast_group notify_grp = {
 756         .name           = "notify",
 757 };
 758
 759 static int __init genl_init(void)
 760 {
 761         int i, err;
 762
 763         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 764                 INIT_LIST_HEAD(&family_ht[i]);
 765
 766         err = genl_register_family(&genl_ctrl);
 767         if (err < 0)
 768                 goto errout;
 769
 770         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
 771         if (err < 0)
 772                 goto errout_register;
 773
 774         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 775
 776         /* we'll bump the group number right afterwards */
 777         genl_sock = netlink_kernel_create(NETLINK_GENERIC, 0, genl_rcv,
 778                                           NULL, THIS_MODULE);
 779         if (genl_sock == NULL)
 780                 panic("GENL: Cannot initialize generic netlink\n");
 781
 782         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 783         if (err < 0)
 784                 goto errout_register;
 785
 786         return 0;
 787
 788 errout_register:
 789         genl_unregister_family(&genl_ctrl);
 790 errout:
 791         panic("GENL: Cannot register controller: %d\n", err);
 792 }
 793
 794 subsys_initcall(genl_init);
 795
 796 EXPORT_SYMBOL(genl_sock);
 797 EXPORT_SYMBOL(genl_register_ops);
 798 EXPORT_SYMBOL(genl_unregister_ops);
 799 EXPORT_SYMBOL(genl_register_family);
 800 EXPORT_SYMBOL(genl_unregister_family);