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_family_rcv_msg(struct genl_family *family,
 548                                struct sk_buff *skb,
 549                                struct nlmsghdr *nlh)
 550 {
 551         struct genl_ops *ops;
 552         struct net *net = sock_net(skb->sk);
 553         struct genl_info info;
 554         struct genlmsghdr *hdr = nlmsg_data(nlh);
 555         struct nlattr **attrbuf;
 556         int hdrlen, err;
 557
 558         /* this family doesn't exist in this netns */
 559         if (!family->netnsok && !net_eq(net, &init_net))
 560                 return -ENOENT;
 561
 562         hdrlen = GENL_HDRLEN + family->hdrsize;
 563         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 564                 return -EINVAL;
 565
 566         ops = genl_get_cmd(hdr->cmd, family);
 567         if (ops == NULL)
 568                 return -EOPNOTSUPP;
 569
 570         if ((ops->flags & GENL_ADMIN_PERM) &&
 571             !capable(CAP_NET_ADMIN))
 572                 return -EPERM;
 573
 574         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 575                 struct netlink_dump_control c = {
 576                         .dump = ops->dumpit,
 577                         .done = ops->done,
 578                 };
 579
 580                 if (ops->dumpit == NULL)
 581                         return -EOPNOTSUPP;
 582
 583                 return netlink_dump_start(net->genl_sock, skb, nlh, &c);
 584         }
 585
 586         if (ops->doit == NULL)
 587                 return -EOPNOTSUPP;
 588
 589         if (family->maxattr && family->parallel_ops) {
 590                 attrbuf = kmalloc((family->maxattr+1) *
 591                                         sizeof(struct nlattr *), GFP_KERNEL);
 592                 if (attrbuf == NULL)
 593                         return -ENOMEM;
 594         } else
 595                 attrbuf = family->attrbuf;
 596
 597         if (attrbuf) {
 598                 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
 599                                   ops->policy);
 600                 if (err < 0)
 601                         goto out;
 602         }
 603
 604         info.snd_seq = nlh->nlmsg_seq;
 605         info.snd_portid = NETLINK_CB(skb).portid;
 606         info.nlhdr = nlh;
 607         info.genlhdr = nlmsg_data(nlh);
 608         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 609         info.attrs = attrbuf;
 610         genl_info_net_set(&info, net);
 611         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 612
 613         if (family->pre_doit) {
 614                 err = family->pre_doit(ops, skb, &info);
 615                 if (err)
 616                         goto out;
 617         }
 618
 619         err = ops->doit(skb, &info);
 620
 621         if (family->post_doit)
 622                 family->post_doit(ops, skb, &info);
 623
 624 out:
 625         if (family->parallel_ops)
 626                 kfree(attrbuf);
 627
 628         return err;
 629 }
 630
 631 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 632 {
 633         struct genl_family *family;
 634         int err;
 635
 636         family = genl_family_find_byid(nlh->nlmsg_type);
 637         if (family == NULL)
 638                 return -ENOENT;
 639
 640         if (!family->parallel_ops)
 641                 genl_lock();
 642
 643         err = genl_family_rcv_msg(family, skb, nlh);
 644
 645         if (!family->parallel_ops)
 646                 genl_unlock();
 647
 648         return err;
 649 }
 650
 651 static void genl_rcv(struct sk_buff *skb)
 652 {
 653         down_read(&cb_lock);
 654         netlink_rcv_skb(skb, &genl_rcv_msg);
 655         up_read(&cb_lock);
 656 }
 657
 658 /**************************************************************************
 659  * Controller
 660  **************************************************************************/
 661
 662 static struct genl_family genl_ctrl = {
 663         .id = GENL_ID_CTRL,
 664         .name = "nlctrl",
 665         .version = 0x2,
 666         .maxattr = CTRL_ATTR_MAX,
 667         .netnsok = true,
 668 };
 669
 670 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 671                           u32 flags, struct sk_buff *skb, u8 cmd)
 672 {
 673         void *hdr;
 674
 675         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 676         if (hdr == NULL)
 677                 return -1;
 678
 679         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 680             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 681             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 682             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 683             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 684                 goto nla_put_failure;
 685
 686         if (!list_empty(&family->ops_list)) {
 687                 struct nlattr *nla_ops;
 688                 struct genl_ops *ops;
 689                 int idx = 1;
 690
 691                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 692                 if (nla_ops == NULL)
 693                         goto nla_put_failure;
 694
 695                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 696                         struct nlattr *nest;
 697
 698                         nest = nla_nest_start(skb, idx++);
 699                         if (nest == NULL)
 700                                 goto nla_put_failure;
 701
 702                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
 703                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags))
 704                                 goto nla_put_failure;
 705
 706                         nla_nest_end(skb, nest);
 707                 }
 708
 709                 nla_nest_end(skb, nla_ops);
 710         }
 711
 712         if (!list_empty(&family->mcast_groups)) {
 713                 struct genl_multicast_group *grp;
 714                 struct nlattr *nla_grps;
 715                 int idx = 1;
 716
 717                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 718                 if (nla_grps == NULL)
 719                         goto nla_put_failure;
 720
 721                 list_for_each_entry(grp, &family->mcast_groups, list) {
 722                         struct nlattr *nest;
 723
 724                         nest = nla_nest_start(skb, idx++);
 725                         if (nest == NULL)
 726                                 goto nla_put_failure;
 727
 728                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 729                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 730                                            grp->name))
 731                                 goto nla_put_failure;
 732
 733                         nla_nest_end(skb, nest);
 734                 }
 735                 nla_nest_end(skb, nla_grps);
 736         }
 737
 738         return genlmsg_end(skb, hdr);
 739
 740 nla_put_failure:
 741         genlmsg_cancel(skb, hdr);
 742         return -EMSGSIZE;
 743 }
 744
 745 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
 746                                 u32 seq, u32 flags, struct sk_buff *skb,
 747                                 u8 cmd)
 748 {
 749         void *hdr;
 750         struct nlattr *nla_grps;
 751         struct nlattr *nest;
 752
 753         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 754         if (hdr == NULL)
 755                 return -1;
 756
 757         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
 758             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
 759                 goto nla_put_failure;
 760
 761         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 762         if (nla_grps == NULL)
 763                 goto nla_put_failure;
 764
 765         nest = nla_nest_start(skb, 1);
 766         if (nest == NULL)
 767                 goto nla_put_failure;
 768
 769         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 770             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 771                            grp->name))
 772                 goto nla_put_failure;
 773
 774         nla_nest_end(skb, nest);
 775         nla_nest_end(skb, nla_grps);
 776
 777         return genlmsg_end(skb, hdr);
 778
 779 nla_put_failure:
 780         genlmsg_cancel(skb, hdr);
 781         return -EMSGSIZE;
 782 }
 783
 784 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 785 {
 786
 787         int i, n = 0;
 788         struct genl_family *rt;
 789         struct net *net = sock_net(skb->sk);
 790         int chains_to_skip = cb->args[0];
 791         int fams_to_skip = cb->args[1];
 792
 793         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 794                 n = 0;
 795                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 796                         if (!rt->netnsok && !net_eq(net, &init_net))
 797                                 continue;
 798                         if (++n < fams_to_skip)
 799                                 continue;
 800                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 801                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 802                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 803                                 goto errout;
 804                 }
 805
 806                 fams_to_skip = 0;
 807         }
 808
 809 errout:
 810         cb->args[0] = i;
 811         cb->args[1] = n;
 812
 813         return skb->len;
 814 }
 815
 816 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 817                                              u32 portid, int seq, u8 cmd)
 818 {
 819         struct sk_buff *skb;
 820         int err;
 821
 822         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 823         if (skb == NULL)
 824                 return ERR_PTR(-ENOBUFS);
 825
 826         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 827         if (err < 0) {
 828                 nlmsg_free(skb);
 829                 return ERR_PTR(err);
 830         }
 831
 832         return skb;
 833 }
 834
 835 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 836                                             u32 portid, int seq, u8 cmd)
 837 {
 838         struct sk_buff *skb;
 839         int err;
 840
 841         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 842         if (skb == NULL)
 843                 return ERR_PTR(-ENOBUFS);
 844
 845         err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd);
 846         if (err < 0) {
 847                 nlmsg_free(skb);
 848                 return ERR_PTR(err);
 849         }
 850
 851         return skb;
 852 }
 853
 854 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 855         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 856         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 857                                     .len = GENL_NAMSIZ - 1 },
 858 };
 859
 860 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 861 {
 862         struct sk_buff *msg;
 863         struct genl_family *res = NULL;
 864         int err = -EINVAL;
 865
 866         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 867                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 868                 res = genl_family_find_byid(id);
 869                 err = -ENOENT;
 870         }
 871
 872         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 873                 char *name;
 874
 875                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 876                 res = genl_family_find_byname(name);
 877 #ifdef CONFIG_MODULES
 878                 if (res == NULL) {
 879                         genl_unlock();
 880                         request_module("net-pf-%d-proto-%d-family-%s",
 881                                        PF_NETLINK, NETLINK_GENERIC, name);
 882                         genl_lock();
 883                         res = genl_family_find_byname(name);
 884                 }
 885 #endif
 886                 err = -ENOENT;
 887         }
 888
 889         if (res == NULL)
 890                 return err;
 891
 892         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 893                 /* family doesn't exist here */
 894                 return -ENOENT;
 895         }
 896
 897         msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
 898                                     CTRL_CMD_NEWFAMILY);
 899         if (IS_ERR(msg))
 900                 return PTR_ERR(msg);
 901
 902         return genlmsg_reply(msg, info);
 903 }
 904
 905 static int genl_ctrl_event(int event, void *data)
 906 {
 907         struct sk_buff *msg;
 908         struct genl_family *family;
 909         struct genl_multicast_group *grp;
 910
 911         /* genl is still initialising */
 912         if (!init_net.genl_sock)
 913                 return 0;
 914
 915         switch (event) {
 916         case CTRL_CMD_NEWFAMILY:
 917         case CTRL_CMD_DELFAMILY:
 918                 family = data;
 919                 msg = ctrl_build_family_msg(family, 0, 0, event);
 920                 break;
 921         case CTRL_CMD_NEWMCAST_GRP:
 922         case CTRL_CMD_DELMCAST_GRP:
 923                 grp = data;
 924                 family = grp->family;
 925                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 926                 break;
 927         default:
 928                 return -EINVAL;
 929         }
 930
 931         if (IS_ERR(msg))
 932                 return PTR_ERR(msg);
 933
 934         if (!family->netnsok) {
 935                 genlmsg_multicast_netns(&init_net, msg, 0,
 936                                         GENL_ID_CTRL, GFP_KERNEL);
 937         } else {
 938                 rcu_read_lock();
 939                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
 940                 rcu_read_unlock();
 941         }
 942
 943         return 0;
 944 }
 945
 946 static struct genl_ops genl_ctrl_ops = {
 947         .cmd            = CTRL_CMD_GETFAMILY,
 948         .doit           = ctrl_getfamily,
 949         .dumpit         = ctrl_dumpfamily,
 950         .policy         = ctrl_policy,
 951 };
 952
 953 static struct genl_multicast_group notify_grp = {
 954         .name           = "notify",
 955 };
 956
 957 static int __net_init genl_pernet_init(struct net *net)
 958 {
 959         struct netlink_kernel_cfg cfg = {
 960                 .input          = genl_rcv,
 961                 .flags          = NL_CFG_F_NONROOT_RECV,
 962         };
 963
 964         /* we'll bump the group number right afterwards */
 965         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
 966
 967         if (!net->genl_sock && net_eq(net, &init_net))
 968                 panic("GENL: Cannot initialize generic netlink\n");
 969
 970         if (!net->genl_sock)
 971                 return -ENOMEM;
 972
 973         return 0;
 974 }
 975
 976 static void __net_exit genl_pernet_exit(struct net *net)
 977 {
 978         netlink_kernel_release(net->genl_sock);
 979         net->genl_sock = NULL;
 980 }
 981
 982 static struct pernet_operations genl_pernet_ops = {
 983         .init = genl_pernet_init,
 984         .exit = genl_pernet_exit,
 985 };
 986
 987 static int __init genl_init(void)
 988 {
 989         int i, err;
 990
 991         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 992                 INIT_LIST_HEAD(&family_ht[i]);
 993
 994         err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
 995         if (err < 0)
 996                 goto problem;
 997
 998         err = register_pernet_subsys(&genl_pernet_ops);
 999         if (err)
1000                 goto problem;
1001
1002         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
1003         if (err < 0)
1004                 goto problem;
1005
1006         return 0;
1007
1008 problem:
1009         panic("GENL: Cannot register controller: %d\n", err);
1010 }
1011
1012 subsys_initcall(genl_init);
1013
1014 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1015                          gfp_t flags)
1016 {
1017         struct sk_buff *tmp;
1018         struct net *net, *prev = NULL;
1019         int err;
1020
1021         for_each_net_rcu(net) {
1022                 if (prev) {
1023                         tmp = skb_clone(skb, flags);
1024                         if (!tmp) {
1025                                 err = -ENOMEM;
1026                                 goto error;
1027                         }
1028                         err = nlmsg_multicast(prev->genl_sock, tmp,
1029                                               portid, group, flags);
1030                         if (err)
1031                                 goto error;
1032                 }
1033
1034                 prev = net;
1035         }
1036
1037         return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1038  error:
1039         kfree_skb(skb);
1040         return err;
1041 }
1042
1043 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group,
1044                             gfp_t flags)
1045 {
1046         return genlmsg_mcast(skb, portid, group, flags);
1047 }
1048 EXPORT_SYMBOL(genlmsg_multicast_allns);
1049
1050 void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
1051                  struct nlmsghdr *nlh, gfp_t flags)
1052 {
1053         struct sock *sk = net->genl_sock;
1054         int report = 0;
1055
1056         if (nlh)
1057                 report = nlmsg_report(nlh);
1058
1059         nlmsg_notify(sk, skb, portid, group, report, flags);
1060 }
1061 EXPORT_SYMBOL(genl_notify);