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 EXPORT_SYMBOL(genl_unregister_mc_group);
 229
 230 static void genl_unregister_mc_groups(struct genl_family *family)
 231 {
 232         struct genl_multicast_group *grp, *tmp;
 233
 234         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 235                 __genl_unregister_mc_group(family, grp);
 236 }
 237
 238 /**
 239  * genl_register_ops - register generic netlink operations
 240  * @family: generic netlink family
 241  * @ops: operations to be registered
 242  *
 243  * Registers the specified operations and assigns them to the specified
 244  * family. Either a doit or dumpit callback must be specified or the
 245  * operation will fail. Only one operation structure per command
 246  * identifier may be registered.
 247  *
 248  * See include/net/genetlink.h for more documenation on the operations
 249  * structure.
 250  *
 251  * Returns 0 on success or a negative error code.
 252  */
 253 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 254 {
 255         int err = -EINVAL;
 256
 257         if (ops->dumpit == NULL && ops->doit == NULL)
 258                 goto errout;
 259
 260         if (genl_get_cmd(ops->cmd, family)) {
 261                 err = -EEXIST;
 262                 goto errout;
 263         }
 264
 265         if (ops->dumpit)
 266                 ops->flags |= GENL_CMD_CAP_DUMP;
 267         if (ops->doit)
 268                 ops->flags |= GENL_CMD_CAP_DO;
 269         if (ops->policy)
 270                 ops->flags |= GENL_CMD_CAP_HASPOL;
 271
 272         genl_lock();
 273         list_add_tail(&ops->ops_list, &family->ops_list);
 274         genl_unlock();
 275
 276         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 277         err = 0;
 278 errout:
 279         return err;
 280 }
 281
 282 /**
 283  * genl_unregister_ops - unregister generic netlink operations
 284  * @family: generic netlink family
 285  * @ops: operations to be unregistered
 286  *
 287  * Unregisters the specified operations and unassigns them from the
 288  * specified family. The operation blocks until the current message
 289  * processing has finished and doesn't start again until the
 290  * unregister process has finished.
 291  *
 292  * Note: It is not necessary to unregister all operations before
 293  *       unregistering the family, unregistering the family will cause
 294  *       all assigned operations to be unregistered automatically.
 295  *
 296  * Returns 0 on success or a negative error code.
 297  */
 298 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 299 {
 300         struct genl_ops *rc;
 301
 302         genl_lock();
 303         list_for_each_entry(rc, &family->ops_list, ops_list) {
 304                 if (rc == ops) {
 305                         list_del(&ops->ops_list);
 306                         genl_unlock();
 307                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
 308                         return 0;
 309                 }
 310         }
 311         genl_unlock();
 312
 313         return -ENOENT;
 314 }
 315
 316 /**
 317  * genl_register_family - register a generic netlink family
 318  * @family: generic netlink family
 319  *
 320  * Registers the specified family after validating it first. Only one
 321  * family may be registered with the same family name or identifier.
 322  * The family id may equal GENL_ID_GENERATE causing an unique id to
 323  * be automatically generated and assigned.
 324  *
 325  * Return 0 on success or a negative error code.
 326  */
 327 int genl_register_family(struct genl_family *family)
 328 {
 329         int err = -EINVAL;
 330
 331         if (family->id && family->id < GENL_MIN_ID)
 332                 goto errout;
 333
 334         if (family->id > GENL_MAX_ID)
 335                 goto errout;
 336
 337         INIT_LIST_HEAD(&family->ops_list);
 338         INIT_LIST_HEAD(&family->mcast_groups);
 339
 340         genl_lock();
 341
 342         if (genl_family_find_byname(family->name)) {
 343                 err = -EEXIST;
 344                 goto errout_locked;
 345         }
 346
 347         if (genl_family_find_byid(family->id)) {
 348                 err = -EEXIST;
 349                 goto errout_locked;
 350         }
 351
 352         if (family->id == GENL_ID_GENERATE) {
 353                 u16 newid = genl_generate_id();
 354
 355                 if (!newid) {
 356                         err = -ENOMEM;
 357                         goto errout_locked;
 358                 }
 359
 360                 family->id = newid;
 361         }
 362
 363         if (family->maxattr) {
 364                 family->attrbuf = kmalloc((family->maxattr+1) *
 365                                         sizeof(struct nlattr *), GFP_KERNEL);
 366                 if (family->attrbuf == NULL) {
 367                         err = -ENOMEM;
 368                         goto errout_locked;
 369                 }
 370         } else
 371                 family->attrbuf = NULL;
 372
 373         list_add_tail(&family->family_list, genl_family_chain(family->id));
 374         genl_unlock();
 375
 376         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 377
 378         return 0;
 379
 380 errout_locked:
 381         genl_unlock();
 382 errout:
 383         return err;
 384 }
 385
 386 /**
 387  * genl_unregister_family - unregister generic netlink family
 388  * @family: generic netlink family
 389  *
 390  * Unregisters the specified family.
 391  *
 392  * Returns 0 on success or a negative error code.
 393  */
 394 int genl_unregister_family(struct genl_family *family)
 395 {
 396         struct genl_family *rc;
 397
 398         genl_lock();
 399
 400         genl_unregister_mc_groups(family);
 401
 402         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 403                 if (family->id != rc->id || strcmp(rc->name, family->name))
 404                         continue;
 405
 406                 list_del(&rc->family_list);
 407                 INIT_LIST_HEAD(&family->ops_list);
 408                 genl_unlock();
 409
 410                 kfree(family->attrbuf);
 411                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 412                 return 0;
 413         }
 414
 415         genl_unlock();
 416
 417         return -ENOENT;
 418 }
 419
 420 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 421 {
 422         struct genl_ops *ops;
 423         struct genl_family *family;
 424         struct genl_info info;
 425         struct genlmsghdr *hdr = nlmsg_data(nlh);
 426         int hdrlen, err;
 427
 428         family = genl_family_find_byid(nlh->nlmsg_type);
 429         if (family == NULL)
 430                 return -ENOENT;
 431
 432         hdrlen = GENL_HDRLEN + family->hdrsize;
 433         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 434                 return -EINVAL;
 435
 436         ops = genl_get_cmd(hdr->cmd, family);
 437         if (ops == NULL)
 438                 return -EOPNOTSUPP;
 439
 440         if ((ops->flags & GENL_ADMIN_PERM) &&
 441             security_netlink_recv(skb, CAP_NET_ADMIN))
 442                 return -EPERM;
 443
 444         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 445                 if (ops->dumpit == NULL)
 446                         return -EOPNOTSUPP;
 447
 448                 genl_unlock();
 449                 err = netlink_dump_start(genl_sock, skb, nlh,
 450                                          ops->dumpit, ops->done);
 451                 genl_lock();
 452                 return err;
 453         }
 454
 455         if (ops->doit == NULL)
 456                 return -EOPNOTSUPP;
 457
 458         if (family->attrbuf) {
 459                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 460                                   ops->policy);
 461                 if (err < 0)
 462                         return err;
 463         }
 464
 465         info.snd_seq = nlh->nlmsg_seq;
 466         info.snd_pid = NETLINK_CB(skb).pid;
 467         info.nlhdr = nlh;
 468         info.genlhdr = nlmsg_data(nlh);
 469         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 470         info.attrs = family->attrbuf;
 471
 472         return ops->doit(skb, &info);
 473 }
 474
 475 static void genl_rcv(struct sk_buff *skb)
 476 {
 477         genl_lock();
 478         netlink_rcv_skb(skb, &genl_rcv_msg);
 479         genl_unlock();
 480 }
 481
 482 /**************************************************************************
 483  * Controller
 484  **************************************************************************/
 485
 486 static struct genl_family genl_ctrl = {
 487         .id = GENL_ID_CTRL,
 488         .name = "nlctrl",
 489         .version = 0x2,
 490         .maxattr = CTRL_ATTR_MAX,
 491 };
 492
 493 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 494                           u32 flags, struct sk_buff *skb, u8 cmd)
 495 {
 496         void *hdr;
 497
 498         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 499         if (hdr == NULL)
 500                 return -1;
 501
 502         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 503         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 504         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 505         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 506         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 507
 508         if (!list_empty(&family->ops_list)) {
 509                 struct nlattr *nla_ops;
 510                 struct genl_ops *ops;
 511                 int idx = 1;
 512
 513                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 514                 if (nla_ops == NULL)
 515                         goto nla_put_failure;
 516
 517                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 518                         struct nlattr *nest;
 519
 520                         nest = nla_nest_start(skb, idx++);
 521                         if (nest == NULL)
 522                                 goto nla_put_failure;
 523
 524                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 525                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 526
 527                         nla_nest_end(skb, nest);
 528                 }
 529
 530                 nla_nest_end(skb, nla_ops);
 531         }
 532
 533         if (!list_empty(&family->mcast_groups)) {
 534                 struct genl_multicast_group *grp;
 535                 struct nlattr *nla_grps;
 536                 int idx = 1;
 537
 538                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 539                 if (nla_grps == NULL)
 540                         goto nla_put_failure;
 541
 542                 list_for_each_entry(grp, &family->mcast_groups, list) {
 543                         struct nlattr *nest;
 544
 545                         nest = nla_nest_start(skb, idx++);
 546                         if (nest == NULL)
 547                                 goto nla_put_failure;
 548
 549                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 550                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 551                                        grp->name);
 552
 553                         nla_nest_end(skb, nest);
 554                 }
 555                 nla_nest_end(skb, nla_grps);
 556         }
 557
 558         return genlmsg_end(skb, hdr);
 559
 560 nla_put_failure:
 561         genlmsg_cancel(skb, hdr);
 562         return -EMSGSIZE;
 563 }
 564
 565 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 566                                 u32 seq, u32 flags, struct sk_buff *skb,
 567                                 u8 cmd)
 568 {
 569         void *hdr;
 570         struct nlattr *nla_grps;
 571         struct nlattr *nest;
 572
 573         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 574         if (hdr == NULL)
 575                 return -1;
 576
 577         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 578         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 579
 580         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 581         if (nla_grps == NULL)
 582                 goto nla_put_failure;
 583
 584         nest = nla_nest_start(skb, 1);
 585         if (nest == NULL)
 586                 goto nla_put_failure;
 587
 588         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 589         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 590                        grp->name);
 591
 592         nla_nest_end(skb, nest);
 593         nla_nest_end(skb, nla_grps);
 594
 595         return genlmsg_end(skb, hdr);
 596
 597 nla_put_failure:
 598         genlmsg_cancel(skb, hdr);
 599         return -EMSGSIZE;
 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         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
 611                 if (i < chains_to_skip)
 612                         continue;
 613                 n = 0;
 614                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 615                         if (++n < fams_to_skip)
 616                                 continue;
 617                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
 618                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 619                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 620                                 goto errout;
 621                 }
 622
 623                 fams_to_skip = 0;
 624         }
 625
 626 errout:
 627         cb->args[0] = i;
 628         cb->args[1] = n;
 629
 630         return skb->len;
 631 }
 632
 633 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 634                                              u32 pid, int seq, u8 cmd)
 635 {
 636         struct sk_buff *skb;
 637         int err;
 638
 639         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 640         if (skb == NULL)
 641                 return ERR_PTR(-ENOBUFS);
 642
 643         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 644         if (err < 0) {
 645                 nlmsg_free(skb);
 646                 return ERR_PTR(err);
 647         }
 648
 649         return skb;
 650 }
 651
 652 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 653                                             u32 pid, int seq, u8 cmd)
 654 {
 655         struct sk_buff *skb;
 656         int err;
 657
 658         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 659         if (skb == NULL)
 660                 return ERR_PTR(-ENOBUFS);
 661
 662         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 663         if (err < 0) {
 664                 nlmsg_free(skb);
 665                 return ERR_PTR(err);
 666         }
 667
 668         return skb;
 669 }
 670
 671 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 672         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 673         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 674                                     .len = GENL_NAMSIZ - 1 },
 675 };
 676
 677 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 678 {
 679         struct sk_buff *msg;
 680         struct genl_family *res = NULL;
 681         int err = -EINVAL;
 682
 683         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 684                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 685                 res = genl_family_find_byid(id);
 686         }
 687
 688         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 689                 char *name;
 690
 691                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 692                 res = genl_family_find_byname(name);
 693         }
 694
 695         if (res == NULL) {
 696                 err = -ENOENT;
 697                 goto errout;
 698         }
 699
 700         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 701                                     CTRL_CMD_NEWFAMILY);
 702         if (IS_ERR(msg)) {
 703                 err = PTR_ERR(msg);
 704                 goto errout;
 705         }
 706
 707         err = genlmsg_reply(msg, info);
 708 errout:
 709         return err;
 710 }
 711
 712 static int genl_ctrl_event(int event, void *data)
 713 {
 714         struct sk_buff *msg;
 715
 716         if (genl_sock == NULL)
 717                 return 0;
 718
 719         switch (event) {
 720         case CTRL_CMD_NEWFAMILY:
 721         case CTRL_CMD_DELFAMILY:
 722                 msg = ctrl_build_family_msg(data, 0, 0, event);
 723                 if (IS_ERR(msg))
 724                         return PTR_ERR(msg);
 725
 726                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 727                 break;
 728         case CTRL_CMD_NEWMCAST_GRP:
 729         case CTRL_CMD_DELMCAST_GRP:
 730                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 731                 if (IS_ERR(msg))
 732                         return PTR_ERR(msg);
 733
 734                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 735                 break;
 736         }
 737
 738         return 0;
 739 }
 740
 741 static struct genl_ops genl_ctrl_ops = {
 742         .cmd            = CTRL_CMD_GETFAMILY,
 743         .doit           = ctrl_getfamily,
 744         .dumpit         = ctrl_dumpfamily,
 745         .policy         = ctrl_policy,
 746 };
 747
 748 static struct genl_multicast_group notify_grp = {
 749         .name           = "notify",
 750 };
 751
 752 static int __init genl_init(void)
 753 {
 754         int i, err;
 755
 756         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 757                 INIT_LIST_HEAD(&family_ht[i]);
 758
 759         err = genl_register_family(&genl_ctrl);
 760         if (err < 0)
 761                 goto errout;
 762
 763         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
 764         if (err < 0)
 765                 goto errout_register;
 766
 767         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 768
 769         /* we'll bump the group number right afterwards */
 770         genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
 771                                           genl_rcv, &genl_mutex, THIS_MODULE);
 772         if (genl_sock == NULL)
 773                 panic("GENL: Cannot initialize generic netlink\n");
 774
 775         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 776         if (err < 0)
 777                 goto errout_register;
 778
 779         return 0;
 780
 781 errout_register:
 782         genl_unregister_family(&genl_ctrl);
 783 errout:
 784         panic("GENL: Cannot register controller: %d\n", err);
 785 }
 786
 787 subsys_initcall(genl_init);
 788
 789 EXPORT_SYMBOL(genl_sock);
 790 EXPORT_SYMBOL(genl_register_ops);
 791 EXPORT_SYMBOL(genl_unregister_ops);
 792 EXPORT_SYMBOL(genl_register_family);
 793 EXPORT_SYMBOL(genl_unregister_family);