release/src-rt-6.x/linux/linux-2.6/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 void genl_unlock(void)
  31 {
  32         mutex_unlock(&genl_mutex);
  33
  34         if (genl_sock && genl_sock->sk_receive_queue.qlen)
  35                 genl_sock->sk_data_ready(genl_sock, 0);
  36 }
  37
  38 #define GENL_FAM_TAB_SIZE       16
  39 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
  40
  41 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  42 /*
  43  * Bitmap of multicast groups that are currently in use.
  44  *
  45  * To avoid an allocation at boot of just one unsigned long,
  46  * declare it global instead.
  47  * Bit 0 is marked as already used since group 0 is invalid.
  48  */
  49 static unsigned long mc_group_start = 0x1;
  50 static unsigned long *mc_groups = &mc_group_start;
  51 static unsigned long mc_groups_longs = 1;
  52
  53 static int genl_ctrl_event(int event, void *data);
  54
  55 static inline unsigned int genl_family_hash(unsigned int id)
  56 {
  57         return id & GENL_FAM_TAB_MASK;
  58 }
  59
  60 static inline struct list_head *genl_family_chain(unsigned int id)
  61 {
  62         return &family_ht[genl_family_hash(id)];
  63 }
  64
  65 static struct genl_family *genl_family_find_byid(unsigned int id)
  66 {
  67         struct genl_family *f;
  68
  69         list_for_each_entry(f, genl_family_chain(id), family_list)
  70                 if (f->id == id)
  71                         return f;
  72
  73         return NULL;
  74 }
  75
  76 static struct genl_family *genl_family_find_byname(char *name)
  77 {
  78         struct genl_family *f;
  79         int i;
  80
  81         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
  82                 list_for_each_entry(f, genl_family_chain(i), family_list)
  83                         if (strcmp(f->name, name) == 0)
  84                                 return f;
  85
  86         return NULL;
  87 }
  88
  89 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
  90 {
  91         struct genl_ops *ops;
  92
  93         list_for_each_entry(ops, &family->ops_list, ops_list)
  94                 if (ops->cmd == cmd)
  95                         return ops;
  96
  97         return NULL;
  98 }
  99
 100 /* Of course we are going to have problems once we hit
 101  * 2^16 alive types, but that can only happen by year 2K
 102 */
 103 static inline u16 genl_generate_id(void)
 104 {
 105         static u16 id_gen_idx;
 106         int overflowed = 0;
 107
 108         do {
 109                 if (id_gen_idx == 0)
 110                         id_gen_idx = GENL_MIN_ID;
 111
 112                 if (++id_gen_idx > GENL_MAX_ID) {
 113                         if (!overflowed) {
 114                                 overflowed = 1;
 115                                 id_gen_idx = 0;
 116                                 continue;
 117                         } else
 118                                 return 0;
 119                 }
 120
 121         } while (genl_family_find_byid(id_gen_idx));
 122
 123         return id_gen_idx;
 124 }
 125
 126 static struct genl_multicast_group notify_grp;
 127
 128 /**
 129  * genl_register_mc_group - register a multicast group
 130  *
 131  * Registers the specified multicast group and notifies userspace
 132  * about the new group.
 133  *
 134  * Returns 0 on success or a negative error code.
 135  *
 136  * @family: The generic netlink family the group shall be registered for.
 137  * @grp: The group to register, must have a name.
 138  */
 139 int genl_register_mc_group(struct genl_family *family,
 140                            struct genl_multicast_group *grp)
 141 {
 142         int id;
 143         unsigned long *new_groups;
 144         int err;
 145
 146         BUG_ON(grp->name[0] == '\0');
 147
 148         genl_lock();
 149
 150         /* special-case our own group */
 151         if (grp == &notify_grp)
 152                 id = GENL_ID_CTRL;
 153         else
 154                 id = find_first_zero_bit(mc_groups,
 155                                          mc_groups_longs * BITS_PER_LONG);
 156
 157
 158         if (id >= mc_groups_longs * BITS_PER_LONG) {
 159                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
 160
 161                 if (mc_groups == &mc_group_start) {
 162                         new_groups = kzalloc(nlen, GFP_KERNEL);
 163                         if (!new_groups) {
 164                                 err = -ENOMEM;
 165                                 goto out;
 166                         }
 167                         mc_groups = new_groups;
 168                         *mc_groups = mc_group_start;
 169                 } else {
 170                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
 171                         if (!new_groups) {
 172                                 err = -ENOMEM;
 173                                 goto out;
 174                         }
 175                         mc_groups = new_groups;
 176                         mc_groups[mc_groups_longs] = 0;
 177                 }
 178                 mc_groups_longs++;
 179         }
 180
 181         err = netlink_change_ngroups(genl_sock,
 182                                      mc_groups_longs * BITS_PER_LONG);
 183         if (err)
 184                 goto out;
 185
 186         grp->id = id;
 187         set_bit(id, mc_groups);
 188         list_add_tail(&grp->list, &family->mcast_groups);
 189         grp->family = family;
 190
 191         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
 192  out:
 193         genl_unlock();
 194         return 0;
 195 }
 196 EXPORT_SYMBOL(genl_register_mc_group);
 197
 198 static void __genl_unregister_mc_group(struct genl_family *family,
 199                                        struct genl_multicast_group *grp)
 200 {
 201         BUG_ON(grp->family != family);
 202         netlink_clear_multicast_users(genl_sock, grp->id);
 203         clear_bit(grp->id, mc_groups);
 204         list_del(&grp->list);
 205         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 206         grp->id = 0;
 207         grp->family = NULL;
 208 }
 209
 210 /**
 211  * genl_unregister_mc_group - unregister a multicast group
 212  *
 213  * Unregisters the specified multicast group and notifies userspace
 214  * about it. All current listeners on the group are removed.
 215  *
 216  * Note: It is not necessary to unregister all multicast groups before
 217  *       unregistering the family, unregistering the family will cause
 218  *       all assigned multicast groups to be unregistered automatically.
 219  *
 220  * @family: Generic netlink family the group belongs to.
 221  * @grp: The group to unregister, must have been registered successfully
 222  *       previously.
 223  */
 224 void genl_unregister_mc_group(struct genl_family *family,
 225                               struct genl_multicast_group *grp)
 226 {
 227         genl_lock();
 228         __genl_unregister_mc_group(family, grp);
 229         genl_unlock();
 230 }
 231 EXPORT_SYMBOL(genl_unregister_mc_group);
 232
 233 static void genl_unregister_mc_groups(struct genl_family *family)
 234 {
 235         struct genl_multicast_group *grp, *tmp;
 236
 237         genl_lock();
 238         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 239                 __genl_unregister_mc_group(family, grp);
 240         genl_unlock();
 241 }
 242
 243 /**
 244  * genl_register_ops - register generic netlink operations
 245  * @family: generic netlink family
 246  * @ops: operations to be registered
 247  *
 248  * Registers the specified operations and assigns them to the specified
 249  * family. Either a doit or dumpit callback must be specified or the
 250  * operation will fail. Only one operation structure per command
 251  * identifier may be registered.
 252  *
 253  * See include/net/genetlink.h for more documenation on the operations
 254  * structure.
 255  *
 256  * Returns 0 on success or a negative error code.
 257  */
 258 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 259 {
 260         int err = -EINVAL;
 261
 262         if (ops->dumpit == NULL && ops->doit == NULL)
 263                 goto errout;
 264
 265         if (genl_get_cmd(ops->cmd, family)) {
 266                 err = -EEXIST;
 267                 goto errout;
 268         }
 269
 270         if (ops->dumpit)
 271                 ops->flags |= GENL_CMD_CAP_DUMP;
 272         if (ops->doit)
 273                 ops->flags |= GENL_CMD_CAP_DO;
 274         if (ops->policy)
 275                 ops->flags |= GENL_CMD_CAP_HASPOL;
 276
 277         genl_lock();
 278         list_add_tail(&ops->ops_list, &family->ops_list);
 279         genl_unlock();
 280
 281         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 282         err = 0;
 283 errout:
 284         return err;
 285 }
 286
 287 /**
 288  * genl_unregister_ops - unregister generic netlink operations
 289  * @family: generic netlink family
 290  * @ops: operations to be unregistered
 291  *
 292  * Unregisters the specified operations and unassigns them from the
 293  * specified family. The operation blocks until the current message
 294  * processing has finished and doesn't start again until the
 295  * unregister process has finished.
 296  *
 297  * Note: It is not necessary to unregister all operations before
 298  *       unregistering the family, unregistering the family will cause
 299  *       all assigned operations to be unregistered automatically.
 300  *
 301  * Returns 0 on success or a negative error code.
 302  */
 303 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 304 {
 305         struct genl_ops *rc;
 306
 307         genl_lock();
 308         list_for_each_entry(rc, &family->ops_list, ops_list) {
 309                 if (rc == ops) {
 310                         list_del(&ops->ops_list);
 311                         genl_unlock();
 312                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
 313                         return 0;
 314                 }
 315         }
 316         genl_unlock();
 317
 318         return -ENOENT;
 319 }
 320
 321 /**
 322  * genl_register_family - register a generic netlink family
 323  * @family: generic netlink family
 324  *
 325  * Registers the specified family after validating it first. Only one
 326  * family may be registered with the same family name or identifier.
 327  * The family id may equal GENL_ID_GENERATE causing an unique id to
 328  * be automatically generated and assigned.
 329  *
 330  * Return 0 on success or a negative error code.
 331  */
 332 int genl_register_family(struct genl_family *family)
 333 {
 334         int err = -EINVAL;
 335
 336         if (family->id && family->id < GENL_MIN_ID)
 337                 goto errout;
 338
 339         if (family->id > GENL_MAX_ID)
 340                 goto errout;
 341
 342         INIT_LIST_HEAD(&family->ops_list);
 343         INIT_LIST_HEAD(&family->mcast_groups);
 344
 345         genl_lock();
 346
 347         if (genl_family_find_byname(family->name)) {
 348                 err = -EEXIST;
 349                 goto errout_locked;
 350         }
 351
 352         if (genl_family_find_byid(family->id)) {
 353                 err = -EEXIST;
 354                 goto errout_locked;
 355         }
 356
 357         if (family->id == GENL_ID_GENERATE) {
 358                 u16 newid = genl_generate_id();
 359
 360                 if (!newid) {
 361                         err = -ENOMEM;
 362                         goto errout_locked;
 363                 }
 364
 365                 family->id = newid;
 366         }
 367
 368         if (family->maxattr) {
 369                 family->attrbuf = kmalloc((family->maxattr+1) *
 370                                         sizeof(struct nlattr *), GFP_KERNEL);
 371                 if (family->attrbuf == NULL) {
 372                         err = -ENOMEM;
 373                         goto errout_locked;
 374                 }
 375         } else
 376                 family->attrbuf = NULL;
 377
 378         list_add_tail(&family->family_list, genl_family_chain(family->id));
 379         genl_unlock();
 380
 381         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 382
 383         return 0;
 384
 385 errout_locked:
 386         genl_unlock();
 387 errout:
 388         return err;
 389 }
 390
 391 /**
 392  * genl_unregister_family - unregister generic netlink family
 393  * @family: generic netlink family
 394  *
 395  * Unregisters the specified family.
 396  *
 397  * Returns 0 on success or a negative error code.
 398  */
 399 int genl_unregister_family(struct genl_family *family)
 400 {
 401         struct genl_family *rc;
 402
 403         genl_unregister_mc_groups(family);
 404
 405         genl_lock();
 406
 407         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 408                 if (family->id != rc->id || strcmp(rc->name, family->name))
 409                         continue;
 410
 411                 list_del(&rc->family_list);
 412                 INIT_LIST_HEAD(&family->ops_list);
 413                 genl_unlock();
 414
 415                 kfree(family->attrbuf);
 416                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 417                 return 0;
 418         }
 419
 420         genl_unlock();
 421
 422         return -ENOENT;
 423 }
 424
 425 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 426 {
 427         struct genl_ops *ops;
 428         struct genl_family *family;
 429         struct genl_info info;
 430         struct genlmsghdr *hdr = nlmsg_data(nlh);
 431         int hdrlen, err;
 432
 433         family = genl_family_find_byid(nlh->nlmsg_type);
 434         if (family == NULL)
 435                 return -ENOENT;
 436
 437         hdrlen = GENL_HDRLEN + family->hdrsize;
 438         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 439                 return -EINVAL;
 440
 441         ops = genl_get_cmd(hdr->cmd, family);
 442         if (ops == NULL)
 443                 return -EOPNOTSUPP;
 444
 445         if ((ops->flags & GENL_ADMIN_PERM) &&
 446             security_netlink_recv(skb, CAP_NET_ADMIN))
 447                 return -EPERM;
 448
 449         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 450                 if (ops->dumpit == NULL)
 451                         return -EOPNOTSUPP;
 452
 453                 return netlink_dump_start(genl_sock, skb, nlh,
 454                                           ops->dumpit, ops->done);
 455         }
 456
 457         if (ops->doit == NULL)
 458                 return -EOPNOTSUPP;
 459
 460         if (family->attrbuf) {
 461                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 462                                   ops->policy);
 463                 if (err < 0)
 464                         return err;
 465         }
 466
 467         info.snd_seq = nlh->nlmsg_seq;
 468         info.snd_pid = NETLINK_CB(skb).pid;
 469         info.nlhdr = nlh;
 470         info.genlhdr = nlmsg_data(nlh);
 471         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 472         info.attrs = family->attrbuf;
 473
 474         return ops->doit(skb, &info);
 475 }
 476
 477 static void genl_rcv(struct sk_buff *skb)
 478 {
 479         genl_lock();
 480         netlink_rcv_skb(skb, &genl_rcv_msg);
 481         genl_unlock();
 482 }
 483
 484 /**************************************************************************
 485  * Controller
 486  **************************************************************************/
 487
 488 static struct genl_family genl_ctrl = {
 489         .id = GENL_ID_CTRL,
 490         .name = "nlctrl",
 491         .version = 0x2,
 492         .maxattr = CTRL_ATTR_MAX,
 493 };
 494
 495 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 496                           u32 flags, struct sk_buff *skb, u8 cmd)
 497 {
 498         void *hdr;
 499
 500         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 501         if (hdr == NULL)
 502                 return -1;
 503
 504         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 505         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 506         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 507         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 508         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 509
 510         if (!list_empty(&family->ops_list)) {
 511                 struct nlattr *nla_ops;
 512                 struct genl_ops *ops;
 513                 int idx = 1;
 514
 515                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 516                 if (nla_ops == NULL)
 517                         goto nla_put_failure;
 518
 519                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 520                         struct nlattr *nest;
 521
 522                         nest = nla_nest_start(skb, idx++);
 523                         if (nest == NULL)
 524                                 goto nla_put_failure;
 525
 526                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 527                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 528
 529                         nla_nest_end(skb, nest);
 530                 }
 531
 532                 nla_nest_end(skb, nla_ops);
 533         }
 534
 535         if (!list_empty(&family->mcast_groups)) {
 536                 struct genl_multicast_group *grp;
 537                 struct nlattr *nla_grps;
 538                 int idx = 1;
 539
 540                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 541                 if (nla_grps == NULL)
 542                         goto nla_put_failure;
 543
 544                 list_for_each_entry(grp, &family->mcast_groups, list) {
 545                         struct nlattr *nest;
 546
 547                         nest = nla_nest_start(skb, idx++);
 548                         if (nest == NULL)
 549                                 goto nla_put_failure;
 550
 551                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 552                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 553                                        grp->name);
 554
 555                         nla_nest_end(skb, nest);
 556                 }
 557                 nla_nest_end(skb, nla_grps);
 558         }
 559
 560         return genlmsg_end(skb, hdr);
 561
 562 nla_put_failure:
 563         return genlmsg_cancel(skb, hdr);
 564 }
 565
 566 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 567                                 u32 seq, u32 flags, struct sk_buff *skb,
 568                                 u8 cmd)
 569 {
 570         void *hdr;
 571         struct nlattr *nla_grps;
 572         struct nlattr *nest;
 573
 574         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 575         if (hdr == NULL)
 576                 return -1;
 577
 578         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 579         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 580
 581         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 582         if (nla_grps == NULL)
 583                 goto nla_put_failure;
 584
 585         nest = nla_nest_start(skb, 1);
 586         if (nest == NULL)
 587                 goto nla_put_failure;
 588
 589         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 590         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 591                        grp->name);
 592
 593         nla_nest_end(skb, nest);
 594         nla_nest_end(skb, nla_grps);
 595
 596         return genlmsg_end(skb, hdr);
 597
 598 nla_put_failure:
 599         return genlmsg_cancel(skb, hdr);
 600 }
 601
 602 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 603 {
 604
 605         int i, n = 0;
 606         struct genl_family *rt;
 607         int chains_to_skip = cb->args[0];
 608         int fams_to_skip = cb->args[1];
 609
 610         if (chains_to_skip != 0)
 611                 genl_lock();
 612
 613         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
 614                 if (i < chains_to_skip)
 615                         continue;
 616                 n = 0;
 617                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 618                         if (++n < fams_to_skip)
 619                                 continue;
 620                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
 621                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 622                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 623                                 goto errout;
 624                 }
 625
 626                 fams_to_skip = 0;
 627         }
 628
 629 errout:
 630         if (chains_to_skip != 0)
 631                 genl_unlock();
 632
 633         cb->args[0] = i;
 634         cb->args[1] = n;
 635
 636         return skb->len;
 637 }
 638
 639 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 640                                              u32 pid, int seq, u8 cmd)
 641 {
 642         struct sk_buff *skb;
 643         int err;
 644
 645         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 646         if (skb == NULL)
 647                 return ERR_PTR(-ENOBUFS);
 648
 649         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 650         if (err < 0) {
 651                 nlmsg_free(skb);
 652                 return ERR_PTR(err);
 653         }
 654
 655         return skb;
 656 }
 657
 658 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 659                                             u32 pid, int seq, u8 cmd)
 660 {
 661         struct sk_buff *skb;
 662         int err;
 663
 664         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 665         if (skb == NULL)
 666                 return ERR_PTR(-ENOBUFS);
 667
 668         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 669         if (err < 0) {
 670                 nlmsg_free(skb);
 671                 return ERR_PTR(err);
 672         }
 673
 674         return skb;
 675 }
 676
 677 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 678         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 679         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 680                                     .len = GENL_NAMSIZ - 1 },
 681 };
 682
 683 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 684 {
 685         struct sk_buff *msg;
 686         struct genl_family *res = NULL;
 687         int err = -EINVAL;
 688
 689         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 690                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 691                 res = genl_family_find_byid(id);
 692         }
 693
 694         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 695                 char *name;
 696
 697                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 698                 res = genl_family_find_byname(name);
 699         }
 700
 701         if (res == NULL) {
 702                 err = -ENOENT;
 703                 goto errout;
 704         }
 705
 706         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 707                                     CTRL_CMD_NEWFAMILY);
 708         if (IS_ERR(msg)) {
 709                 err = PTR_ERR(msg);
 710                 goto errout;
 711         }
 712
 713         err = genlmsg_reply(msg, info);
 714 errout:
 715         return err;
 716 }
 717
 718 static int genl_ctrl_event(int event, void *data)
 719 {
 720         struct sk_buff *msg;
 721
 722         if (genl_sock == NULL)
 723                 return 0;
 724
 725         switch (event) {
 726         case CTRL_CMD_NEWFAMILY:
 727         case CTRL_CMD_DELFAMILY:
 728                 msg = ctrl_build_family_msg(data, 0, 0, event);
 729                 if (IS_ERR(msg))
 730                         return PTR_ERR(msg);
 731
 732                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 733                 break;
 734         case CTRL_CMD_NEWMCAST_GRP:
 735         case CTRL_CMD_DELMCAST_GRP:
 736                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 737                 if (IS_ERR(msg))
 738                         return PTR_ERR(msg);
 739
 740                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 741                 break;
 742         }
 743
 744         return 0;
 745 }
 746
 747 static struct genl_ops genl_ctrl_ops = {
 748         .cmd            = CTRL_CMD_GETFAMILY,
 749         .doit           = ctrl_getfamily,
 750         .dumpit         = ctrl_dumpfamily,
 751         .policy         = ctrl_policy,
 752 };
 753
 754 static struct genl_multicast_group notify_grp = {
 755         .name           = "notify",
 756 };
 757
 758 static int __init genl_init(void)
 759 {
 760         int i, err;
 761
 762         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 763                 INIT_LIST_HEAD(&family_ht[i]);
 764
 765         err = genl_register_family(&genl_ctrl);
 766         if (err < 0)
 767                 goto errout;
 768
 769         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
 770         if (err < 0)
 771                 goto errout_register;
 772
 773         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 774
 775         /* we'll bump the group number right afterwards */
 776         genl_sock = netlink_kernel_create(NETLINK_GENERIC, 0, genl_rcv,
 777                                           NULL, THIS_MODULE);
 778         if (genl_sock == NULL)
 779                 panic("GENL: Cannot initialize generic netlink\n");
 780
 781         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 782         if (err < 0)
 783                 goto errout_register;
 784
 785         return 0;
 786
 787 errout_register:
 788         genl_unregister_family(&genl_ctrl);
 789 errout:
 790         panic("GENL: Cannot register controller: %d\n", err);
 791 }
 792
 793 subsys_initcall(genl_init);
 794
 795 EXPORT_SYMBOL(genl_sock);
 796 EXPORT_SYMBOL(genl_register_ops);
 797 EXPORT_SYMBOL(genl_unregister_ops);
 798 EXPORT_SYMBOL(genl_register_family);
 799 EXPORT_SYMBOL(genl_unregister_family);