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/slab.h>
  12 #include <linux/errno.h>
  13 #include <linux/types.h>
  14 #include <linux/socket.h>
  15 #include <linux/string.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/mutex.h>
  18 #include <linux/bitmap.h>
  19 #include <linux/rwsem.h>
  20 #include <net/sock.h>
  21 #include <net/genetlink.h>
  22
  23 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
  24 static DECLARE_RWSEM(cb_lock);
  25
  26 void genl_lock(void)
  27 {
  28         mutex_lock(&genl_mutex);
  29 }
  30 EXPORT_SYMBOL(genl_lock);
  31
  32 void genl_unlock(void)
  33 {
  34         mutex_unlock(&genl_mutex);
  35 }
  36 EXPORT_SYMBOL(genl_unlock);
  37
  38 #ifdef CONFIG_LOCKDEP
  39 int lockdep_genl_is_held(void)
  40 {
  41         return lockdep_is_held(&genl_mutex);
  42 }
  43 EXPORT_SYMBOL(lockdep_genl_is_held);
  44 #endif
  45
  46 static void genl_lock_all(void)
  47 {
  48         down_write(&cb_lock);
  49         genl_lock();
  50 }
  51
  52 static void genl_unlock_all(void)
  53 {
  54         genl_unlock();
  55         up_write(&cb_lock);
  56 }
  57
  58 #define GENL_FAM_TAB_SIZE       16
  59 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
  60
  61 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  62 /*
  63  * Bitmap of multicast groups that are currently in use.
  64  *
  65  * To avoid an allocation at boot of just one unsigned long,
  66  * declare it global instead.
  67  * Bit 0 is marked as already used since group 0 is invalid.
  68  */
  69 static unsigned long mc_group_start = 0x1;
  70 static unsigned long *mc_groups = &mc_group_start;
  71 static unsigned long mc_groups_longs = 1;
  72
  73 static int genl_ctrl_event(int event, void *data);
  74
  75 static inline unsigned int genl_family_hash(unsigned int id)
  76 {
  77         return id & GENL_FAM_TAB_MASK;
  78 }
  79
  80 static inline struct list_head *genl_family_chain(unsigned int id)
  81 {
  82         return &family_ht[genl_family_hash(id)];
  83 }
  84
  85 static struct genl_family *genl_family_find_byid(unsigned int id)
  86 {
  87         struct genl_family *f;
  88
  89         list_for_each_entry(f, genl_family_chain(id), family_list)
  90                 if (f->id == id)
  91                         return f;
  92
  93         return NULL;
  94 }
  95
  96 static struct genl_family *genl_family_find_byname(char *name)
  97 {
  98         struct genl_family *f;
  99         int i;
 100
 101         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 102                 list_for_each_entry(f, genl_family_chain(i), family_list)
 103                         if (strcmp(f->name, name) == 0)
 104                                 return f;
 105
 106         return NULL;
 107 }
 108
 109 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
 110 {
 111         struct genl_ops *ops;
 112
 113         list_for_each_entry(ops, &family->ops_list, ops_list)
 114                 if (ops->cmd == cmd)
 115                         return ops;
 116
 117         return NULL;
 118 }
 119
 120 /* Of course we are going to have problems once we hit
 121  * 2^16 alive types, but that can only happen by year 2K
 122 */
 123 static u16 genl_generate_id(void)
 124 {
 125         static u16 id_gen_idx = GENL_MIN_ID;
 126         int i;
 127
 128         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
 129                 if (!genl_family_find_byid(id_gen_idx))
 130                         return id_gen_idx;
 131                 if (++id_gen_idx > GENL_MAX_ID)
 132                         id_gen_idx = GENL_MIN_ID;
 133         }
 134
 135         return 0;
 136 }
 137
 138 static struct genl_multicast_group notify_grp;
 139
 140 /**
 141  * genl_register_mc_group - register a multicast group
 142  *
 143  * Registers the specified multicast group and notifies userspace
 144  * about the new group.
 145  *
 146  * Returns 0 on success or a negative error code.
 147  *
 148  * @family: The generic netlink family the group shall be registered for.
 149  * @grp: The group to register, must have a name.
 150  */
 151 int genl_register_mc_group(struct genl_family *family,
 152                            struct genl_multicast_group *grp)
 153 {
 154         int id;
 155         unsigned long *new_groups;
 156         int err = 0;
 157
 158         BUG_ON(grp->name[0] == '\0');
 159         BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);
 160
 161         genl_lock_all();
 162
 163         /* special-case our own group */
 164         if (grp == &notify_grp)
 165                 id = GENL_ID_CTRL;
 166         else
 167                 id = find_first_zero_bit(mc_groups,
 168                                          mc_groups_longs * BITS_PER_LONG);
 169
 170
 171         if (id >= mc_groups_longs * BITS_PER_LONG) {
 172                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
 173
 174                 if (mc_groups == &mc_group_start) {
 175                         new_groups = kzalloc(nlen, GFP_KERNEL);
 176                         if (!new_groups) {
 177                                 err = -ENOMEM;
 178                                 goto out;
 179                         }
 180                         mc_groups = new_groups;
 181                         *mc_groups = mc_group_start;
 182                 } else {
 183                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
 184                         if (!new_groups) {
 185                                 err = -ENOMEM;
 186                                 goto out;
 187                         }
 188                         mc_groups = new_groups;
 189                         mc_groups[mc_groups_longs] = 0;
 190                 }
 191                 mc_groups_longs++;
 192         }
 193
 194         if (family->netnsok) {
 195                 struct net *net;
 196
 197                 netlink_table_grab();
 198                 rcu_read_lock();
 199                 for_each_net_rcu(net) {
 200                         err = __netlink_change_ngroups(net->genl_sock,
 201                                         mc_groups_longs * BITS_PER_LONG);
 202                         if (err) {
 203                                 /*
 204                                  * No need to roll back, can only fail if
 205                                  * memory allocation fails and then the
 206                                  * number of _possible_ groups has been
 207                                  * increased on some sockets which is ok.
 208                                  */
 209                                 rcu_read_unlock();
 210                                 netlink_table_ungrab();
 211                                 goto out;
 212                         }
 213                 }
 214                 rcu_read_unlock();
 215                 netlink_table_ungrab();
 216         } else {
 217                 err = netlink_change_ngroups(init_net.genl_sock,
 218                                              mc_groups_longs * BITS_PER_LONG);
 219                 if (err)
 220                         goto out;
 221         }
 222
 223         grp->id = id;
 224         set_bit(id, mc_groups);
 225         list_add_tail(&grp->list, &family->mcast_groups);
 226         grp->family = family;
 227
 228         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
 229  out:
 230         genl_unlock_all();
 231         return err;
 232 }
 233 EXPORT_SYMBOL(genl_register_mc_group);
 234
 235 static void __genl_unregister_mc_group(struct genl_family *family,
 236                                        struct genl_multicast_group *grp)
 237 {
 238         struct net *net;
 239         BUG_ON(grp->family != family);
 240
 241         netlink_table_grab();
 242         rcu_read_lock();
 243         for_each_net_rcu(net)
 244                 __netlink_clear_multicast_users(net->genl_sock, grp->id);
 245         rcu_read_unlock();
 246         netlink_table_ungrab();
 247
 248         clear_bit(grp->id, mc_groups);
 249         list_del(&grp->list);
 250         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 251         grp->id = 0;
 252         grp->family = NULL;
 253 }
 254
 255 /**
 256  * genl_unregister_mc_group - unregister a multicast group
 257  *
 258  * Unregisters the specified multicast group and notifies userspace
 259  * about it. All current listeners on the group are removed.
 260  *
 261  * Note: It is not necessary to unregister all multicast groups before
 262  *       unregistering the family, unregistering the family will cause
 263  *       all assigned multicast groups to be unregistered automatically.
 264  *
 265  * @family: Generic netlink family the group belongs to.
 266  * @grp: The group to unregister, must have been registered successfully
 267  *       previously.
 268  */
 269 void genl_unregister_mc_group(struct genl_family *family,
 270                               struct genl_multicast_group *grp)
 271 {
 272         genl_lock_all();
 273         __genl_unregister_mc_group(family, grp);
 274         genl_unlock_all();
 275 }
 276 EXPORT_SYMBOL(genl_unregister_mc_group);
 277
 278 static void genl_unregister_mc_groups(struct genl_family *family)
 279 {
 280         struct genl_multicast_group *grp, *tmp;
 281
 282         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 283                 __genl_unregister_mc_group(family, grp);
 284 }
 285
 286 /**
 287  * genl_register_ops - register generic netlink operations
 288  * @family: generic netlink family
 289  * @ops: operations to be registered
 290  *
 291  * Registers the specified operations and assigns them to the specified
 292  * family. Either a doit or dumpit callback must be specified or the
 293  * operation will fail. Only one operation structure per command
 294  * identifier may be registered.
 295  *
 296  * See include/net/genetlink.h for more documenation on the operations
 297  * structure.
 298  *
 299  * Returns 0 on success or a negative error code.
 300  */
 301 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 302 {
 303         int err = -EINVAL;
 304
 305         if (ops->dumpit == NULL && ops->doit == NULL)
 306                 goto errout;
 307
 308         if (genl_get_cmd(ops->cmd, family)) {
 309                 err = -EEXIST;
 310                 goto errout;
 311         }
 312
 313         if (ops->dumpit)
 314                 ops->flags |= GENL_CMD_CAP_DUMP;
 315         if (ops->doit)
 316                 ops->flags |= GENL_CMD_CAP_DO;
 317         if (ops->policy)
 318                 ops->flags |= GENL_CMD_CAP_HASPOL;
 319
 320         genl_lock_all();
 321         list_add_tail(&ops->ops_list, &family->ops_list);
 322         genl_unlock_all();
 323
 324         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 325         err = 0;
 326 errout:
 327         return err;
 328 }
 329 EXPORT_SYMBOL(genl_register_ops);
 330
 331 /**
 332  * genl_unregister_ops - unregister generic netlink operations
 333  * @family: generic netlink family
 334  * @ops: operations to be unregistered
 335  *
 336  * Unregisters the specified operations and unassigns them from the
 337  * specified family. The operation blocks until the current message
 338  * processing has finished and doesn't start again until the
 339  * unregister process has finished.
 340  *
 341  * Note: It is not necessary to unregister all operations before
 342  *       unregistering the family, unregistering the family will cause
 343  *       all assigned operations to be unregistered automatically.
 344  *
 345  * Returns 0 on success or a negative error code.
 346  */
 347 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 348 {
 349         struct genl_ops *rc;
 350
 351         genl_lock_all();
 352         list_for_each_entry(rc, &family->ops_list, ops_list) {
 353                 if (rc == ops) {
 354                         list_del(&ops->ops_list);
 355                         genl_unlock_all();
 356                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
 357                         return 0;
 358                 }
 359         }
 360         genl_unlock_all();
 361
 362         return -ENOENT;
 363 }
 364 EXPORT_SYMBOL(genl_unregister_ops);
 365
 366 /**
 367  * __genl_register_family - register a generic netlink family
 368  * @family: generic netlink family
 369  *
 370  * Registers the specified family after validating it first. Only one
 371  * family may be registered with the same family name or identifier.
 372  * The family id may equal GENL_ID_GENERATE causing an unique id to
 373  * be automatically generated and assigned.
 374  *
 375  * Return 0 on success or a negative error code.
 376  */
 377 int __genl_register_family(struct genl_family *family)
 378 {
 379         int err = -EINVAL;
 380
 381         if (family->id && family->id < GENL_MIN_ID)
 382                 goto errout;
 383
 384         if (family->id > GENL_MAX_ID)
 385                 goto errout;
 386
 387         INIT_LIST_HEAD(&family->ops_list);
 388         INIT_LIST_HEAD(&family->mcast_groups);
 389
 390         genl_lock_all();
 391
 392         if (genl_family_find_byname(family->name)) {
 393                 err = -EEXIST;
 394                 goto errout_locked;
 395         }
 396
 397         if (family->id == GENL_ID_GENERATE) {
 398                 u16 newid = genl_generate_id();
 399
 400                 if (!newid) {
 401                         err = -ENOMEM;
 402                         goto errout_locked;
 403                 }
 404
 405                 family->id = newid;
 406         } else if (genl_family_find_byid(family->id)) {
 407                 err = -EEXIST;
 408                 goto errout_locked;
 409         }
 410
 411         if (family->maxattr && !family->parallel_ops) {
 412                 family->attrbuf = kmalloc((family->maxattr+1) *
 413                                         sizeof(struct nlattr *), GFP_KERNEL);
 414                 if (family->attrbuf == NULL) {
 415                         err = -ENOMEM;
 416                         goto errout_locked;
 417                 }
 418         } else
 419                 family->attrbuf = NULL;
 420
 421         list_add_tail(&family->family_list, genl_family_chain(family->id));
 422         genl_unlock_all();
 423
 424         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 425
 426         return 0;
 427
 428 errout_locked:
 429         genl_unlock_all();
 430 errout:
 431         return err;
 432 }
 433 EXPORT_SYMBOL(__genl_register_family);
 434
 435 /**
 436  * __genl_register_family_with_ops - register a generic netlink family
 437  * @family: generic netlink family
 438  * @ops: operations to be registered
 439  * @n_ops: number of elements to register
 440  *
 441  * Registers the specified family and operations from the specified table.
 442  * Only one family may be registered with the same family name or identifier.
 443  *
 444  * The family id may equal GENL_ID_GENERATE causing an unique id to
 445  * be automatically generated and assigned.
 446  *
 447  * Either a doit or dumpit callback must be specified for every registered
 448  * operation or the function will fail. Only one operation structure per
 449  * command identifier may be registered.
 450  *
 451  * See include/net/genetlink.h for more documenation on the operations
 452  * structure.
 453  *
 454  * This is equivalent to calling genl_register_family() followed by
 455  * genl_register_ops() for every operation entry in the table taking
 456  * care to unregister the family on error path.
 457  *
 458  * Return 0 on success or a negative error code.
 459  */
 460 int __genl_register_family_with_ops(struct genl_family *family,
 461         struct genl_ops *ops, size_t n_ops)
 462 {
 463         int err, i;
 464
 465         err = __genl_register_family(family);
 466         if (err)
 467                 return err;
 468
 469         for (i = 0; i < n_ops; ++i, ++ops) {
 470                 err = genl_register_ops(family, ops);
 471                 if (err)
 472                         goto err_out;
 473         }
 474         return 0;
 475 err_out:
 476         genl_unregister_family(family);
 477         return err;
 478 }
 479 EXPORT_SYMBOL(__genl_register_family_with_ops);
 480
 481 /**
 482  * genl_unregister_family - unregister generic netlink family
 483  * @family: generic netlink family
 484  *
 485  * Unregisters the specified family.
 486  *
 487  * Returns 0 on success or a negative error code.
 488  */
 489 int genl_unregister_family(struct genl_family *family)
 490 {
 491         struct genl_family *rc;
 492
 493         genl_lock_all();
 494
 495         genl_unregister_mc_groups(family);
 496
 497         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 498                 if (family->id != rc->id || strcmp(rc->name, family->name))
 499                         continue;
 500
 501                 list_del(&rc->family_list);
 502                 INIT_LIST_HEAD(&family->ops_list);
 503                 genl_unlock_all();
 504
 505                 kfree(family->attrbuf);
 506                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 507                 return 0;
 508         }
 509
 510         genl_unlock_all();
 511
 512         return -ENOENT;
 513 }
 514 EXPORT_SYMBOL(genl_unregister_family);
 515
 516 /**
 517  * genlmsg_put - Add generic netlink header to netlink message
 518  * @skb: socket buffer holding the message
 519  * @portid: netlink portid the message is addressed to
 520  * @seq: sequence number (usually the one of the sender)
 521  * @family: generic netlink family
 522  * @flags: netlink message flags
 523  * @cmd: generic netlink command
 524  *
 525  * Returns pointer to user specific header
 526  */
 527 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 528                                 struct genl_family *family, int flags, u8 cmd)
 529 {
 530         struct nlmsghdr *nlh;
 531         struct genlmsghdr *hdr;
 532
 533         nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 534                         family->hdrsize, flags);
 535         if (nlh == NULL)
 536                 return NULL;
 537
 538         hdr = nlmsg_data(nlh);
 539         hdr->cmd = cmd;
 540         hdr->version = family->version;
 541         hdr->reserved = 0;
 542
 543         return (char *) hdr + GENL_HDRLEN;
 544 }
 545 EXPORT_SYMBOL(genlmsg_put);
 546
 547 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 548 {
 549         struct genl_ops *ops = cb->data;
 550         int rc;
 551
 552         genl_lock();
 553         rc = ops->dumpit(skb, cb);
 554         genl_unlock();
 555         return rc;
 556 }
 557
 558 static int genl_lock_done(struct netlink_callback *cb)
 559 {
 560         struct genl_ops *ops = cb->data;
 561         int rc = 0;
 562
 563         if (ops->done) {
 564                 genl_lock();
 565                 rc = ops->done(cb);
 566                 genl_unlock();
 567         }
 568         return rc;
 569 }
 570
 571 static int genl_family_rcv_msg(struct genl_family *family,
 572                                struct sk_buff *skb,
 573                                struct nlmsghdr *nlh)
 574 {
 575         struct genl_ops *ops;
 576         struct net *net = sock_net(skb->sk);
 577         struct genl_info info;
 578         struct genlmsghdr *hdr = nlmsg_data(nlh);
 579         struct nlattr **attrbuf;
 580         int hdrlen, err;
 581
 582         /* this family doesn't exist in this netns */
 583         if (!family->netnsok && !net_eq(net, &init_net))
 584                 return -ENOENT;
 585
 586         hdrlen = GENL_HDRLEN + family->hdrsize;
 587         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 588                 return -EINVAL;
 589
 590         ops = genl_get_cmd(hdr->cmd, family);
 591         if (ops == NULL)
 592                 return -EOPNOTSUPP;
 593
 594         if ((ops->flags & GENL_ADMIN_PERM) &&
 595             !capable(CAP_NET_ADMIN))
 596                 return -EPERM;
 597
 598         if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
 599                 int rc;
 600
 601                 if (ops->dumpit == NULL)
 602                         return -EOPNOTSUPP;
 603
 604                 if (!family->parallel_ops) {
 605                         struct netlink_dump_control c = {
 606                                 .module = family->module,
 607                                 .data = ops,
 608                                 .dump = genl_lock_dumpit,
 609                                 .done = genl_lock_done,
 610                         };
 611
 612                         genl_unlock();
 613                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 614                         genl_lock();
 615
 616                 } else {
 617                         struct netlink_dump_control c = {
 618                                 .module = family->module,
 619                                 .dump = ops->dumpit,
 620                                 .done = ops->done,
 621                         };
 622
 623                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 624                 }
 625
 626                 return rc;
 627         }
 628
 629         if (ops->doit == NULL)
 630                 return -EOPNOTSUPP;
 631
 632         if (family->maxattr && family->parallel_ops) {
 633                 attrbuf = kmalloc((family->maxattr+1) *
 634                                         sizeof(struct nlattr *), GFP_KERNEL);
 635                 if (attrbuf == NULL)
 636                         return -ENOMEM;
 637         } else
 638                 attrbuf = family->attrbuf;
 639
 640         if (attrbuf) {
 641                 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
 642                                   ops->policy);
 643                 if (err < 0)
 644                         goto out;
 645         }
 646
 647         info.snd_seq = nlh->nlmsg_seq;
 648         info.snd_portid = NETLINK_CB(skb).portid;
 649         info.nlhdr = nlh;
 650         info.genlhdr = nlmsg_data(nlh);
 651         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 652         info.attrs = attrbuf;
 653         genl_info_net_set(&info, net);
 654         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 655
 656         if (family->pre_doit) {
 657                 err = family->pre_doit(ops, skb, &info);
 658                 if (err)
 659                         goto out;
 660         }
 661
 662         err = ops->doit(skb, &info);
 663
 664         if (family->post_doit)
 665                 family->post_doit(ops, skb, &info);
 666
 667 out:
 668         if (family->parallel_ops)
 669                 kfree(attrbuf);
 670
 671         return err;
 672 }
 673
 674 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 675 {
 676         struct genl_family *family;
 677         int err;
 678
 679         family = genl_family_find_byid(nlh->nlmsg_type);
 680         if (family == NULL)
 681                 return -ENOENT;
 682
 683         if (!family->parallel_ops)
 684                 genl_lock();
 685
 686         err = genl_family_rcv_msg(family, skb, nlh);
 687
 688         if (!family->parallel_ops)
 689                 genl_unlock();
 690
 691         return err;
 692 }
 693
 694 static void genl_rcv(struct sk_buff *skb)
 695 {
 696         down_read(&cb_lock);
 697         netlink_rcv_skb(skb, &genl_rcv_msg);
 698         up_read(&cb_lock);
 699 }
 700
 701 /**************************************************************************
 702  * Controller
 703  **************************************************************************/
 704
 705 static struct genl_family genl_ctrl = {
 706         .id = GENL_ID_CTRL,
 707         .name = "nlctrl",
 708         .version = 0x2,
 709         .maxattr = CTRL_ATTR_MAX,
 710         .netnsok = true,
 711 };
 712
 713 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 714                           u32 flags, struct sk_buff *skb, u8 cmd)
 715 {
 716         void *hdr;
 717
 718         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 719         if (hdr == NULL)
 720                 return -1;
 721
 722         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 723             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 724             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 725             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 726             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 727                 goto nla_put_failure;
 728
 729         if (!list_empty(&family->ops_list)) {
 730                 struct nlattr *nla_ops;
 731                 struct genl_ops *ops;
 732                 int idx = 1;
 733
 734                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 735                 if (nla_ops == NULL)
 736                         goto nla_put_failure;
 737
 738                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 739                         struct nlattr *nest;
 740
 741                         nest = nla_nest_start(skb, idx++);
 742                         if (nest == NULL)
 743                                 goto nla_put_failure;
 744
 745                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
 746                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags))
 747                                 goto nla_put_failure;
 748
 749                         nla_nest_end(skb, nest);
 750                 }
 751
 752                 nla_nest_end(skb, nla_ops);
 753         }
 754
 755         if (!list_empty(&family->mcast_groups)) {
 756                 struct genl_multicast_group *grp;
 757                 struct nlattr *nla_grps;
 758                 int idx = 1;
 759
 760                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 761                 if (nla_grps == NULL)
 762                         goto nla_put_failure;
 763
 764                 list_for_each_entry(grp, &family->mcast_groups, list) {
 765                         struct nlattr *nest;
 766
 767                         nest = nla_nest_start(skb, idx++);
 768                         if (nest == NULL)
 769                                 goto nla_put_failure;
 770
 771                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 772                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 773                                            grp->name))
 774                                 goto nla_put_failure;
 775
 776                         nla_nest_end(skb, nest);
 777                 }
 778                 nla_nest_end(skb, nla_grps);
 779         }
 780
 781         return genlmsg_end(skb, hdr);
 782
 783 nla_put_failure:
 784         genlmsg_cancel(skb, hdr);
 785         return -EMSGSIZE;
 786 }
 787
 788 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
 789                                 u32 seq, u32 flags, struct sk_buff *skb,
 790                                 u8 cmd)
 791 {
 792         void *hdr;
 793         struct nlattr *nla_grps;
 794         struct nlattr *nest;
 795
 796         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 797         if (hdr == NULL)
 798                 return -1;
 799
 800         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
 801             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
 802                 goto nla_put_failure;
 803
 804         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 805         if (nla_grps == NULL)
 806                 goto nla_put_failure;
 807
 808         nest = nla_nest_start(skb, 1);
 809         if (nest == NULL)
 810                 goto nla_put_failure;
 811
 812         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 813             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 814                            grp->name))
 815                 goto nla_put_failure;
 816
 817         nla_nest_end(skb, nest);
 818         nla_nest_end(skb, nla_grps);
 819
 820         return genlmsg_end(skb, hdr);
 821
 822 nla_put_failure:
 823         genlmsg_cancel(skb, hdr);
 824         return -EMSGSIZE;
 825 }
 826
 827 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 828 {
 829
 830         int i, n = 0;
 831         struct genl_family *rt;
 832         struct net *net = sock_net(skb->sk);
 833         int chains_to_skip = cb->args[0];
 834         int fams_to_skip = cb->args[1];
 835
 836         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 837                 n = 0;
 838                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 839                         if (!rt->netnsok && !net_eq(net, &init_net))
 840                                 continue;
 841                         if (++n < fams_to_skip)
 842                                 continue;
 843                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 844                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 845                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 846                                 goto errout;
 847                 }
 848
 849                 fams_to_skip = 0;
 850         }
 851
 852 errout:
 853         cb->args[0] = i;
 854         cb->args[1] = n;
 855
 856         return skb->len;
 857 }
 858
 859 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 860                                              u32 portid, int seq, u8 cmd)
 861 {
 862         struct sk_buff *skb;
 863         int err;
 864
 865         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 866         if (skb == NULL)
 867                 return ERR_PTR(-ENOBUFS);
 868
 869         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 870         if (err < 0) {
 871                 nlmsg_free(skb);
 872                 return ERR_PTR(err);
 873         }
 874
 875         return skb;
 876 }
 877
 878 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 879                                             u32 portid, int seq, u8 cmd)
 880 {
 881         struct sk_buff *skb;
 882         int err;
 883
 884         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 885         if (skb == NULL)
 886                 return ERR_PTR(-ENOBUFS);
 887
 888         err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd);
 889         if (err < 0) {
 890                 nlmsg_free(skb);
 891                 return ERR_PTR(err);
 892         }
 893
 894         return skb;
 895 }
 896
 897 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 898         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 899         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 900                                     .len = GENL_NAMSIZ - 1 },
 901 };
 902
 903 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 904 {
 905         struct sk_buff *msg;
 906         struct genl_family *res = NULL;
 907         int err = -EINVAL;
 908
 909         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 910                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 911                 res = genl_family_find_byid(id);
 912                 err = -ENOENT;
 913         }
 914
 915         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 916                 char *name;
 917
 918                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 919                 res = genl_family_find_byname(name);
 920 #ifdef CONFIG_MODULES
 921                 if (res == NULL) {
 922                         genl_unlock();
 923                         up_read(&cb_lock);
 924                         request_module("net-pf-%d-proto-%d-family-%s",
 925                                        PF_NETLINK, NETLINK_GENERIC, name);
 926                         down_read(&cb_lock);
 927                         genl_lock();
 928                         res = genl_family_find_byname(name);
 929                 }
 930 #endif
 931                 err = -ENOENT;
 932         }
 933
 934         if (res == NULL)
 935                 return err;
 936
 937         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 938                 /* family doesn't exist here */
 939                 return -ENOENT;
 940         }
 941
 942         msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
 943                                     CTRL_CMD_NEWFAMILY);
 944         if (IS_ERR(msg))
 945                 return PTR_ERR(msg);
 946
 947         return genlmsg_reply(msg, info);
 948 }
 949
 950 static int genl_ctrl_event(int event, void *data)
 951 {
 952         struct sk_buff *msg;
 953         struct genl_family *family;
 954         struct genl_multicast_group *grp;
 955
 956         /* genl is still initialising */
 957         if (!init_net.genl_sock)
 958                 return 0;
 959
 960         switch (event) {
 961         case CTRL_CMD_NEWFAMILY:
 962         case CTRL_CMD_DELFAMILY:
 963                 family = data;
 964                 msg = ctrl_build_family_msg(family, 0, 0, event);
 965                 break;
 966         case CTRL_CMD_NEWMCAST_GRP:
 967         case CTRL_CMD_DELMCAST_GRP:
 968                 grp = data;
 969                 family = grp->family;
 970                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 971                 break;
 972         default:
 973                 return -EINVAL;
 974         }
 975
 976         if (IS_ERR(msg))
 977                 return PTR_ERR(msg);
 978
 979         if (!family->netnsok) {
 980                 genlmsg_multicast_netns(&init_net, msg, 0,
 981                                         GENL_ID_CTRL, GFP_KERNEL);
 982         } else {
 983                 rcu_read_lock();
 984                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
 985                 rcu_read_unlock();
 986         }
 987
 988         return 0;
 989 }
 990
 991 static struct genl_ops genl_ctrl_ops = {
 992         .cmd            = CTRL_CMD_GETFAMILY,
 993         .doit           = ctrl_getfamily,
 994         .dumpit         = ctrl_dumpfamily,
 995         .policy         = ctrl_policy,
 996 };
 997
 998 static struct genl_multicast_group notify_grp = {
 999         .name           = "notify",
1000 };
1001
1002 static int __net_init genl_pernet_init(struct net *net)
1003 {
1004         struct netlink_kernel_cfg cfg = {
1005                 .input          = genl_rcv,
1006                 .flags          = NL_CFG_F_NONROOT_RECV,
1007         };
1008
1009         /* we'll bump the group number right afterwards */
1010         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1011
1012         if (!net->genl_sock && net_eq(net, &init_net))
1013                 panic("GENL: Cannot initialize generic netlink\n");
1014
1015         if (!net->genl_sock)
1016                 return -ENOMEM;
1017
1018         return 0;
1019 }
1020
1021 static void __net_exit genl_pernet_exit(struct net *net)
1022 {
1023         netlink_kernel_release(net->genl_sock);
1024         net->genl_sock = NULL;
1025 }
1026
1027 static struct pernet_operations genl_pernet_ops = {
1028         .init = genl_pernet_init,
1029         .exit = genl_pernet_exit,
1030 };
1031
1032 static int __init genl_init(void)
1033 {
1034         int i, err;
1035
1036         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
1037                 INIT_LIST_HEAD(&family_ht[i]);
1038
1039         err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
1040         if (err < 0)
1041                 goto problem;
1042
1043         err = register_pernet_subsys(&genl_pernet_ops);
1044         if (err)
1045                 goto problem;
1046
1047         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
1048         if (err < 0)
1049                 goto problem;
1050
1051         return 0;
1052
1053 problem:
1054         panic("GENL: Cannot register controller: %d\n", err);
1055 }
1056
1057 subsys_initcall(genl_init);
1058
1059 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1060                          gfp_t flags)
1061 {
1062         struct sk_buff *tmp;
1063         struct net *net, *prev = NULL;
1064         int err;
1065
1066         for_each_net_rcu(net) {
1067                 if (prev) {
1068                         tmp = skb_clone(skb, flags);
1069                         if (!tmp) {
1070                                 err = -ENOMEM;
1071                                 goto error;
1072                         }
1073                         err = nlmsg_multicast(prev->genl_sock, tmp,
1074                                               portid, group, flags);
1075                         if (err)
1076                                 goto error;
1077                 }
1078
1079                 prev = net;
1080         }
1081
1082         return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1083  error:
1084         kfree_skb(skb);
1085         return err;
1086 }
1087
1088 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group,
1089                             gfp_t flags)
1090 {
1091         return genlmsg_mcast(skb, portid, group, flags);
1092 }
1093 EXPORT_SYMBOL(genlmsg_multicast_allns);
1094
1095 void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
1096                  struct nlmsghdr *nlh, gfp_t flags)
1097 {
1098         struct sock *sk = net->genl_sock;
1099         int report = 0;
1100
1101         if (nlh)
1102                 report = nlmsg_report(nlh);
1103
1104         nlmsg_notify(sk, skb, portid, group, report, flags);
1105 }
1106 EXPORT_SYMBOL(genl_notify);