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         genl_lock();
 234         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 235                 __genl_unregister_mc_group(family, grp);
 236         genl_unlock();
 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 sk_buff *skb)
 474 {
 475         genl_lock();
 476         netlink_rcv_skb(skb, &genl_rcv_msg);
 477         genl_unlock();
 478 }
 479
 480 /**************************************************************************
 481  * Controller
 482  **************************************************************************/
 483
 484 static struct genl_family genl_ctrl = {
 485         .id = GENL_ID_CTRL,
 486         .name = "nlctrl",
 487         .version = 0x2,
 488         .maxattr = CTRL_ATTR_MAX,
 489 };
 490
 491 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 492                           u32 flags, struct sk_buff *skb, u8 cmd)
 493 {
 494         void *hdr;
 495
 496         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 497         if (hdr == NULL)
 498                 return -1;
 499
 500         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 501         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 502         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 503         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 504         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 505
 506         if (!list_empty(&family->ops_list)) {
 507                 struct nlattr *nla_ops;
 508                 struct genl_ops *ops;
 509                 int idx = 1;
 510
 511                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 512                 if (nla_ops == NULL)
 513                         goto nla_put_failure;
 514
 515                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 516                         struct nlattr *nest;
 517
 518                         nest = nla_nest_start(skb, idx++);
 519                         if (nest == NULL)
 520                                 goto nla_put_failure;
 521
 522                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 523                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 524
 525                         nla_nest_end(skb, nest);
 526                 }
 527
 528                 nla_nest_end(skb, nla_ops);
 529         }
 530
 531         if (!list_empty(&family->mcast_groups)) {
 532                 struct genl_multicast_group *grp;
 533                 struct nlattr *nla_grps;
 534                 int idx = 1;
 535
 536                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 537                 if (nla_grps == NULL)
 538                         goto nla_put_failure;
 539
 540                 list_for_each_entry(grp, &family->mcast_groups, list) {
 541                         struct nlattr *nest;
 542
 543                         nest = nla_nest_start(skb, idx++);
 544                         if (nest == NULL)
 545                                 goto nla_put_failure;
 546
 547                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 548                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 549                                        grp->name);
 550
 551                         nla_nest_end(skb, nest);
 552                 }
 553                 nla_nest_end(skb, nla_grps);
 554         }
 555
 556         return genlmsg_end(skb, hdr);
 557
 558 nla_put_failure:
 559         return genlmsg_cancel(skb, hdr);
 560 }
 561
 562 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 563                                 u32 seq, u32 flags, struct sk_buff *skb,
 564                                 u8 cmd)
 565 {
 566         void *hdr;
 567         struct nlattr *nla_grps;
 568         struct nlattr *nest;
 569
 570         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 571         if (hdr == NULL)
 572                 return -1;
 573
 574         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 575         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 576
 577         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 578         if (nla_grps == NULL)
 579                 goto nla_put_failure;
 580
 581         nest = nla_nest_start(skb, 1);
 582         if (nest == NULL)
 583                 goto nla_put_failure;
 584
 585         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 586         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 587                        grp->name);
 588
 589         nla_nest_end(skb, nest);
 590         nla_nest_end(skb, nla_grps);
 591
 592         return genlmsg_end(skb, hdr);
 593
 594 nla_put_failure:
 595         return genlmsg_cancel(skb, hdr);
 596 }
 597
 598 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 599 {
 600
 601         int i, n = 0;
 602         struct genl_family *rt;
 603         int chains_to_skip = cb->args[0];
 604         int fams_to_skip = cb->args[1];
 605
 606         if (chains_to_skip != 0)
 607                 genl_lock();
 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         if (chains_to_skip != 0)
 627                 genl_unlock();
 628
 629         cb->args[0] = i;
 630         cb->args[1] = n;
 631
 632         return skb->len;
 633 }
 634
 635 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 636                                              u32 pid, int seq, u8 cmd)
 637 {
 638         struct sk_buff *skb;
 639         int err;
 640
 641         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 642         if (skb == NULL)
 643                 return ERR_PTR(-ENOBUFS);
 644
 645         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 646         if (err < 0) {
 647                 nlmsg_free(skb);
 648                 return ERR_PTR(err);
 649         }
 650
 651         return skb;
 652 }
 653
 654 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 655                                             u32 pid, int seq, u8 cmd)
 656 {
 657         struct sk_buff *skb;
 658         int err;
 659
 660         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 661         if (skb == NULL)
 662                 return ERR_PTR(-ENOBUFS);
 663
 664         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 665         if (err < 0) {
 666                 nlmsg_free(skb);
 667                 return ERR_PTR(err);
 668         }
 669
 670         return skb;
 671 }
 672
 673 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 674         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 675         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 676                                     .len = GENL_NAMSIZ - 1 },
 677 };
 678
 679 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 680 {
 681         struct sk_buff *msg;
 682         struct genl_family *res = NULL;
 683         int err = -EINVAL;
 684
 685         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 686                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 687                 res = genl_family_find_byid(id);
 688         }
 689
 690         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 691                 char *name;
 692
 693                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 694                 res = genl_family_find_byname(name);
 695         }
 696
 697         if (res == NULL) {
 698                 err = -ENOENT;
 699                 goto errout;
 700         }
 701
 702         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 703                                     CTRL_CMD_NEWFAMILY);
 704         if (IS_ERR(msg)) {
 705                 err = PTR_ERR(msg);
 706                 goto errout;
 707         }
 708
 709         err = genlmsg_reply(msg, info);
 710 errout:
 711         return err;
 712 }
 713
 714 static int genl_ctrl_event(int event, void *data)
 715 {
 716         struct sk_buff *msg;
 717
 718         if (genl_sock == NULL)
 719                 return 0;
 720
 721         switch (event) {
 722         case CTRL_CMD_NEWFAMILY:
 723         case CTRL_CMD_DELFAMILY:
 724                 msg = ctrl_build_family_msg(data, 0, 0, event);
 725                 if (IS_ERR(msg))
 726                         return PTR_ERR(msg);
 727
 728                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 729                 break;
 730         case CTRL_CMD_NEWMCAST_GRP:
 731         case CTRL_CMD_DELMCAST_GRP:
 732                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 733                 if (IS_ERR(msg))
 734                         return PTR_ERR(msg);
 735
 736                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 737                 break;
 738         }
 739
 740         return 0;
 741 }
 742
 743 static struct genl_ops genl_ctrl_ops = {
 744         .cmd            = CTRL_CMD_GETFAMILY,
 745         .doit           = ctrl_getfamily,
 746         .dumpit         = ctrl_dumpfamily,
 747         .policy         = ctrl_policy,
 748 };
 749
 750 static struct genl_multicast_group notify_grp = {
 751         .name           = "notify",
 752 };
 753
 754 static int __init genl_init(void)
 755 {
 756         int i, err;
 757
 758         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 759                 INIT_LIST_HEAD(&family_ht[i]);
 760
 761         err = genl_register_family(&genl_ctrl);
 762         if (err < 0)
 763                 goto errout;
 764
 765         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
 766         if (err < 0)
 767                 goto errout_register;
 768
 769         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 770
 771         /* we'll bump the group number right afterwards */
 772         genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
 773                                           genl_rcv, NULL, THIS_MODULE);
 774         if (genl_sock == NULL)
 775                 panic("GENL: Cannot initialize generic netlink\n");
 776
 777         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 778         if (err < 0)
 779                 goto errout_register;
 780
 781         return 0;
 782
 783 errout_register:
 784         genl_unregister_family(&genl_ctrl);
 785 errout:
 786         panic("GENL: Cannot register controller: %d\n", err);
 787 }
 788
 789 subsys_initcall(genl_init);
 790
 791 EXPORT_SYMBOL(genl_sock);
 792 EXPORT_SYMBOL(genl_register_ops);
 793 EXPORT_SYMBOL(genl_unregister_ops);
 794 EXPORT_SYMBOL(genl_register_family);
 795 EXPORT_SYMBOL(genl_unregister_family);