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_register_family_with_ops - register a generic netlink family
 388  * @family: generic netlink family
 389  * @ops: operations to be registered
 390  * @n_ops: number of elements to register
 391  *
 392  * Registers the specified family and operations from the specified table.
 393  * Only one family may be registered with the same family name or identifier.
 394  *
 395  * The family id may equal GENL_ID_GENERATE causing an unique id to
 396  * be automatically generated and assigned.
 397  *
 398  * Either a doit or dumpit callback must be specified for every registered
 399  * operation or the function will fail. Only one operation structure per
 400  * command identifier may be registered.
 401  *
 402  * See include/net/genetlink.h for more documenation on the operations
 403  * structure.
 404  *
 405  * This is equivalent to calling genl_register_family() followed by
 406  * genl_register_ops() for every operation entry in the table taking
 407  * care to unregister the family on error path.
 408  *
 409  * Return 0 on success or a negative error code.
 410  */
 411 int genl_register_family_with_ops(struct genl_family *family,
 412         struct genl_ops *ops, size_t n_ops)
 413 {
 414         int err, i;
 415
 416         err = genl_register_family(family);
 417         if (err)
 418                 return err;
 419
 420         for (i = 0; i < n_ops; ++i, ++ops) {
 421                 err = genl_register_ops(family, ops);
 422                 if (err)
 423                         goto err_out;
 424         }
 425         return 0;
 426 err_out:
 427         genl_unregister_family(family);
 428         return err;
 429 }
 430 EXPORT_SYMBOL(genl_register_family_with_ops);
 431
 432 /**
 433  * genl_unregister_family - unregister generic netlink family
 434  * @family: generic netlink family
 435  *
 436  * Unregisters the specified family.
 437  *
 438  * Returns 0 on success or a negative error code.
 439  */
 440 int genl_unregister_family(struct genl_family *family)
 441 {
 442         struct genl_family *rc;
 443
 444         genl_lock();
 445
 446         genl_unregister_mc_groups(family);
 447
 448         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 449                 if (family->id != rc->id || strcmp(rc->name, family->name))
 450                         continue;
 451
 452                 list_del(&rc->family_list);
 453                 INIT_LIST_HEAD(&family->ops_list);
 454                 genl_unlock();
 455
 456                 kfree(family->attrbuf);
 457                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 458                 return 0;
 459         }
 460
 461         genl_unlock();
 462
 463         return -ENOENT;
 464 }
 465
 466 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 467 {
 468         struct genl_ops *ops;
 469         struct genl_family *family;
 470         struct genl_info info;
 471         struct genlmsghdr *hdr = nlmsg_data(nlh);
 472         int hdrlen, err;
 473
 474         family = genl_family_find_byid(nlh->nlmsg_type);
 475         if (family == NULL)
 476                 return -ENOENT;
 477
 478         hdrlen = GENL_HDRLEN + family->hdrsize;
 479         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 480                 return -EINVAL;
 481
 482         ops = genl_get_cmd(hdr->cmd, family);
 483         if (ops == NULL)
 484                 return -EOPNOTSUPP;
 485
 486         if ((ops->flags & GENL_ADMIN_PERM) &&
 487             security_netlink_recv(skb, CAP_NET_ADMIN))
 488                 return -EPERM;
 489
 490         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 491                 if (ops->dumpit == NULL)
 492                         return -EOPNOTSUPP;
 493
 494                 genl_unlock();
 495                 err = netlink_dump_start(genl_sock, skb, nlh,
 496                                          ops->dumpit, ops->done);
 497                 genl_lock();
 498                 return err;
 499         }
 500
 501         if (ops->doit == NULL)
 502                 return -EOPNOTSUPP;
 503
 504         if (family->attrbuf) {
 505                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 506                                   ops->policy);
 507                 if (err < 0)
 508                         return err;
 509         }
 510
 511         info.snd_seq = nlh->nlmsg_seq;
 512         info.snd_pid = NETLINK_CB(skb).pid;
 513         info.nlhdr = nlh;
 514         info.genlhdr = nlmsg_data(nlh);
 515         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 516         info.attrs = family->attrbuf;
 517
 518         return ops->doit(skb, &info);
 519 }
 520
 521 static void genl_rcv(struct sk_buff *skb)
 522 {
 523         genl_lock();
 524         netlink_rcv_skb(skb, &genl_rcv_msg);
 525         genl_unlock();
 526 }
 527
 528 /**************************************************************************
 529  * Controller
 530  **************************************************************************/
 531
 532 static struct genl_family genl_ctrl = {
 533         .id = GENL_ID_CTRL,
 534         .name = "nlctrl",
 535         .version = 0x2,
 536         .maxattr = CTRL_ATTR_MAX,
 537 };
 538
 539 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 540                           u32 flags, struct sk_buff *skb, u8 cmd)
 541 {
 542         void *hdr;
 543
 544         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 545         if (hdr == NULL)
 546                 return -1;
 547
 548         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 549         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 550         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 551         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 552         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 553
 554         if (!list_empty(&family->ops_list)) {
 555                 struct nlattr *nla_ops;
 556                 struct genl_ops *ops;
 557                 int idx = 1;
 558
 559                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 560                 if (nla_ops == NULL)
 561                         goto nla_put_failure;
 562
 563                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 564                         struct nlattr *nest;
 565
 566                         nest = nla_nest_start(skb, idx++);
 567                         if (nest == NULL)
 568                                 goto nla_put_failure;
 569
 570                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 571                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 572
 573                         nla_nest_end(skb, nest);
 574                 }
 575
 576                 nla_nest_end(skb, nla_ops);
 577         }
 578
 579         if (!list_empty(&family->mcast_groups)) {
 580                 struct genl_multicast_group *grp;
 581                 struct nlattr *nla_grps;
 582                 int idx = 1;
 583
 584                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 585                 if (nla_grps == NULL)
 586                         goto nla_put_failure;
 587
 588                 list_for_each_entry(grp, &family->mcast_groups, list) {
 589                         struct nlattr *nest;
 590
 591                         nest = nla_nest_start(skb, idx++);
 592                         if (nest == NULL)
 593                                 goto nla_put_failure;
 594
 595                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 596                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 597                                        grp->name);
 598
 599                         nla_nest_end(skb, nest);
 600                 }
 601                 nla_nest_end(skb, nla_grps);
 602         }
 603
 604         return genlmsg_end(skb, hdr);
 605
 606 nla_put_failure:
 607         genlmsg_cancel(skb, hdr);
 608         return -EMSGSIZE;
 609 }
 610
 611 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 612                                 u32 seq, u32 flags, struct sk_buff *skb,
 613                                 u8 cmd)
 614 {
 615         void *hdr;
 616         struct nlattr *nla_grps;
 617         struct nlattr *nest;
 618
 619         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 620         if (hdr == NULL)
 621                 return -1;
 622
 623         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 624         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 625
 626         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 627         if (nla_grps == NULL)
 628                 goto nla_put_failure;
 629
 630         nest = nla_nest_start(skb, 1);
 631         if (nest == NULL)
 632                 goto nla_put_failure;
 633
 634         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 635         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 636                        grp->name);
 637
 638         nla_nest_end(skb, nest);
 639         nla_nest_end(skb, nla_grps);
 640
 641         return genlmsg_end(skb, hdr);
 642
 643 nla_put_failure:
 644         genlmsg_cancel(skb, hdr);
 645         return -EMSGSIZE;
 646 }
 647
 648 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 649 {
 650
 651         int i, n = 0;
 652         struct genl_family *rt;
 653         int chains_to_skip = cb->args[0];
 654         int fams_to_skip = cb->args[1];
 655
 656         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
 657                 if (i < chains_to_skip)
 658                         continue;
 659                 n = 0;
 660                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 661                         if (++n < fams_to_skip)
 662                                 continue;
 663                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
 664                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 665                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 666                                 goto errout;
 667                 }
 668
 669                 fams_to_skip = 0;
 670         }
 671
 672 errout:
 673         cb->args[0] = i;
 674         cb->args[1] = n;
 675
 676         return skb->len;
 677 }
 678
 679 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 680                                              u32 pid, int seq, u8 cmd)
 681 {
 682         struct sk_buff *skb;
 683         int err;
 684
 685         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 686         if (skb == NULL)
 687                 return ERR_PTR(-ENOBUFS);
 688
 689         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 690         if (err < 0) {
 691                 nlmsg_free(skb);
 692                 return ERR_PTR(err);
 693         }
 694
 695         return skb;
 696 }
 697
 698 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 699                                             u32 pid, int seq, u8 cmd)
 700 {
 701         struct sk_buff *skb;
 702         int err;
 703
 704         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 705         if (skb == NULL)
 706                 return ERR_PTR(-ENOBUFS);
 707
 708         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 709         if (err < 0) {
 710                 nlmsg_free(skb);
 711                 return ERR_PTR(err);
 712         }
 713
 714         return skb;
 715 }
 716
 717 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 718         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 719         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 720                                     .len = GENL_NAMSIZ - 1 },
 721 };
 722
 723 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 724 {
 725         struct sk_buff *msg;
 726         struct genl_family *res = NULL;
 727         int err = -EINVAL;
 728
 729         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 730                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 731                 res = genl_family_find_byid(id);
 732         }
 733
 734         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 735                 char *name;
 736
 737                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 738                 res = genl_family_find_byname(name);
 739         }
 740
 741         if (res == NULL) {
 742                 err = -ENOENT;
 743                 goto errout;
 744         }
 745
 746         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 747                                     CTRL_CMD_NEWFAMILY);
 748         if (IS_ERR(msg)) {
 749                 err = PTR_ERR(msg);
 750                 goto errout;
 751         }
 752
 753         err = genlmsg_reply(msg, info);
 754 errout:
 755         return err;
 756 }
 757
 758 static int genl_ctrl_event(int event, void *data)
 759 {
 760         struct sk_buff *msg;
 761
 762         if (genl_sock == NULL)
 763                 return 0;
 764
 765         switch (event) {
 766         case CTRL_CMD_NEWFAMILY:
 767         case CTRL_CMD_DELFAMILY:
 768                 msg = ctrl_build_family_msg(data, 0, 0, event);
 769                 if (IS_ERR(msg))
 770                         return PTR_ERR(msg);
 771
 772                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 773                 break;
 774         case CTRL_CMD_NEWMCAST_GRP:
 775         case CTRL_CMD_DELMCAST_GRP:
 776                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 777                 if (IS_ERR(msg))
 778                         return PTR_ERR(msg);
 779
 780                 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
 781                 break;
 782         }
 783
 784         return 0;
 785 }
 786
 787 static struct genl_ops genl_ctrl_ops = {
 788         .cmd            = CTRL_CMD_GETFAMILY,
 789         .doit           = ctrl_getfamily,
 790         .dumpit         = ctrl_dumpfamily,
 791         .policy         = ctrl_policy,
 792 };
 793
 794 static struct genl_multicast_group notify_grp = {
 795         .name           = "notify",
 796 };
 797
 798 static int __init genl_init(void)
 799 {
 800         int i, err;
 801
 802         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 803                 INIT_LIST_HEAD(&family_ht[i]);
 804
 805         err = genl_register_family(&genl_ctrl);
 806         if (err < 0)
 807                 goto errout;
 808
 809         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
 810         if (err < 0)
 811                 goto errout_register;
 812
 813         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 814
 815         /* we'll bump the group number right afterwards */
 816         genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
 817                                           genl_rcv, &genl_mutex, THIS_MODULE);
 818         if (genl_sock == NULL)
 819                 panic("GENL: Cannot initialize generic netlink\n");
 820
 821         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 822         if (err < 0)
 823                 goto errout_register;
 824
 825         return 0;
 826
 827 errout_register:
 828         genl_unregister_family(&genl_ctrl);
 829 errout:
 830         panic("GENL: Cannot register controller: %d\n", err);
 831 }
 832
 833 subsys_initcall(genl_init);
 834
 835 EXPORT_SYMBOL(genl_sock);
 836 EXPORT_SYMBOL(genl_register_ops);
 837 EXPORT_SYMBOL(genl_unregister_ops);
 838 EXPORT_SYMBOL(genl_register_family);
 839 EXPORT_SYMBOL(genl_unregister_family);