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