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 static int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 287 {
 288         int err = -EINVAL;
 289
 290         if (ops->dumpit == NULL && ops->doit == NULL)
 291                 goto errout;
 292
 293         if (genl_get_cmd(ops->cmd, family)) {
 294                 err = -EEXIST;
 295                 goto errout;
 296         }
 297
 298         if (ops->dumpit)
 299                 ops->flags |= GENL_CMD_CAP_DUMP;
 300         if (ops->doit)
 301                 ops->flags |= GENL_CMD_CAP_DO;
 302         if (ops->policy)
 303                 ops->flags |= GENL_CMD_CAP_HASPOL;
 304
 305         genl_lock_all();
 306         list_add_tail(&ops->ops_list, &family->ops_list);
 307         genl_unlock_all();
 308
 309         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 310         err = 0;
 311 errout:
 312         return err;
 313 }
 314
 315 /**
 316  * __genl_register_family - register a generic netlink family
 317  * @family: generic netlink family
 318  *
 319  * Registers the specified family after validating it first. Only one
 320  * family may be registered with the same family name or identifier.
 321  * The family id may equal GENL_ID_GENERATE causing an unique id to
 322  * be automatically generated and assigned.
 323  *
 324  * Return 0 on success or a negative error code.
 325  */
 326 int __genl_register_family(struct genl_family *family)
 327 {
 328         int err = -EINVAL;
 329
 330         if (family->id && family->id < GENL_MIN_ID)
 331                 goto errout;
 332
 333         if (family->id > GENL_MAX_ID)
 334                 goto errout;
 335
 336         INIT_LIST_HEAD(&family->ops_list);
 337         INIT_LIST_HEAD(&family->mcast_groups);
 338
 339         genl_lock_all();
 340
 341         if (genl_family_find_byname(family->name)) {
 342                 err = -EEXIST;
 343                 goto errout_locked;
 344         }
 345
 346         if (family->id == GENL_ID_GENERATE) {
 347                 u16 newid = genl_generate_id();
 348
 349                 if (!newid) {
 350                         err = -ENOMEM;
 351                         goto errout_locked;
 352                 }
 353
 354                 family->id = newid;
 355         } else if (genl_family_find_byid(family->id)) {
 356                 err = -EEXIST;
 357                 goto errout_locked;
 358         }
 359
 360         if (family->maxattr && !family->parallel_ops) {
 361                 family->attrbuf = kmalloc((family->maxattr+1) *
 362                                         sizeof(struct nlattr *), GFP_KERNEL);
 363                 if (family->attrbuf == NULL) {
 364                         err = -ENOMEM;
 365                         goto errout_locked;
 366                 }
 367         } else
 368                 family->attrbuf = NULL;
 369
 370         list_add_tail(&family->family_list, genl_family_chain(family->id));
 371         genl_unlock_all();
 372
 373         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 374
 375         return 0;
 376
 377 errout_locked:
 378         genl_unlock_all();
 379 errout:
 380         return err;
 381 }
 382 EXPORT_SYMBOL(__genl_register_family);
 383
 384 /**
 385  * __genl_register_family_with_ops - register a generic netlink family
 386  * @family: generic netlink family
 387  * @ops: operations to be registered
 388  * @n_ops: number of elements to register
 389  *
 390  * Registers the specified family and operations from the specified table.
 391  * Only one family may be registered with the same family name or identifier.
 392  *
 393  * The family id may equal GENL_ID_GENERATE causing an unique id to
 394  * be automatically generated and assigned.
 395  *
 396  * Either a doit or dumpit callback must be specified for every registered
 397  * operation or the function will fail. Only one operation structure per
 398  * command identifier may be registered.
 399  *
 400  * See include/net/genetlink.h for more documenation on the operations
 401  * structure.
 402  *
 403  * Return 0 on success or a negative error code.
 404  */
 405 int __genl_register_family_with_ops(struct genl_family *family,
 406         struct genl_ops *ops, size_t n_ops)
 407 {
 408         int err, i;
 409
 410         err = __genl_register_family(family);
 411         if (err)
 412                 return err;
 413
 414         for (i = 0; i < n_ops; ++i, ++ops) {
 415                 err = genl_register_ops(family, ops);
 416                 if (err)
 417                         goto err_out;
 418         }
 419         return 0;
 420 err_out:
 421         genl_unregister_family(family);
 422         return err;
 423 }
 424 EXPORT_SYMBOL(__genl_register_family_with_ops);
 425
 426 /**
 427  * genl_unregister_family - unregister generic netlink family
 428  * @family: generic netlink family
 429  *
 430  * Unregisters the specified family.
 431  *
 432  * Returns 0 on success or a negative error code.
 433  */
 434 int genl_unregister_family(struct genl_family *family)
 435 {
 436         struct genl_family *rc;
 437
 438         genl_lock_all();
 439
 440         genl_unregister_mc_groups(family);
 441
 442         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 443                 if (family->id != rc->id || strcmp(rc->name, family->name))
 444                         continue;
 445
 446                 list_del(&rc->family_list);
 447                 INIT_LIST_HEAD(&family->ops_list);
 448                 genl_unlock_all();
 449
 450                 kfree(family->attrbuf);
 451                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 452                 return 0;
 453         }
 454
 455         genl_unlock_all();
 456
 457         return -ENOENT;
 458 }
 459 EXPORT_SYMBOL(genl_unregister_family);
 460
 461 /**
 462  * genlmsg_put - Add generic netlink header to netlink message
 463  * @skb: socket buffer holding the message
 464  * @portid: netlink portid the message is addressed to
 465  * @seq: sequence number (usually the one of the sender)
 466  * @family: generic netlink family
 467  * @flags: netlink message flags
 468  * @cmd: generic netlink command
 469  *
 470  * Returns pointer to user specific header
 471  */
 472 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 473                                 struct genl_family *family, int flags, u8 cmd)
 474 {
 475         struct nlmsghdr *nlh;
 476         struct genlmsghdr *hdr;
 477
 478         nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 479                         family->hdrsize, flags);
 480         if (nlh == NULL)
 481                 return NULL;
 482
 483         hdr = nlmsg_data(nlh);
 484         hdr->cmd = cmd;
 485         hdr->version = family->version;
 486         hdr->reserved = 0;
 487
 488         return (char *) hdr + GENL_HDRLEN;
 489 }
 490 EXPORT_SYMBOL(genlmsg_put);
 491
 492 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 493 {
 494         struct genl_ops *ops = cb->data;
 495         int rc;
 496
 497         genl_lock();
 498         rc = ops->dumpit(skb, cb);
 499         genl_unlock();
 500         return rc;
 501 }
 502
 503 static int genl_lock_done(struct netlink_callback *cb)
 504 {
 505         struct genl_ops *ops = cb->data;
 506         int rc = 0;
 507
 508         if (ops->done) {
 509                 genl_lock();
 510                 rc = ops->done(cb);
 511                 genl_unlock();
 512         }
 513         return rc;
 514 }
 515
 516 static int genl_family_rcv_msg(struct genl_family *family,
 517                                struct sk_buff *skb,
 518                                struct nlmsghdr *nlh)
 519 {
 520         struct genl_ops *ops;
 521         struct net *net = sock_net(skb->sk);
 522         struct genl_info info;
 523         struct genlmsghdr *hdr = nlmsg_data(nlh);
 524         struct nlattr **attrbuf;
 525         int hdrlen, err;
 526
 527         /* this family doesn't exist in this netns */
 528         if (!family->netnsok && !net_eq(net, &init_net))
 529                 return -ENOENT;
 530
 531         hdrlen = GENL_HDRLEN + family->hdrsize;
 532         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 533                 return -EINVAL;
 534
 535         ops = genl_get_cmd(hdr->cmd, family);
 536         if (ops == NULL)
 537                 return -EOPNOTSUPP;
 538
 539         if ((ops->flags & GENL_ADMIN_PERM) &&
 540             !capable(CAP_NET_ADMIN))
 541                 return -EPERM;
 542
 543         if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
 544                 int rc;
 545
 546                 if (ops->dumpit == NULL)
 547                         return -EOPNOTSUPP;
 548
 549                 if (!family->parallel_ops) {
 550                         struct netlink_dump_control c = {
 551                                 .module = family->module,
 552                                 .data = ops,
 553                                 .dump = genl_lock_dumpit,
 554                                 .done = genl_lock_done,
 555                         };
 556
 557                         genl_unlock();
 558                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 559                         genl_lock();
 560
 561                 } else {
 562                         struct netlink_dump_control c = {
 563                                 .module = family->module,
 564                                 .dump = ops->dumpit,
 565                                 .done = ops->done,
 566                         };
 567
 568                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 569                 }
 570
 571                 return rc;
 572         }
 573
 574         if (ops->doit == NULL)
 575                 return -EOPNOTSUPP;
 576
 577         if (family->maxattr && family->parallel_ops) {
 578                 attrbuf = kmalloc((family->maxattr+1) *
 579                                         sizeof(struct nlattr *), GFP_KERNEL);
 580                 if (attrbuf == NULL)
 581                         return -ENOMEM;
 582         } else
 583                 attrbuf = family->attrbuf;
 584
 585         if (attrbuf) {
 586                 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
 587                                   ops->policy);
 588                 if (err < 0)
 589                         goto out;
 590         }
 591
 592         info.snd_seq = nlh->nlmsg_seq;
 593         info.snd_portid = NETLINK_CB(skb).portid;
 594         info.nlhdr = nlh;
 595         info.genlhdr = nlmsg_data(nlh);
 596         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 597         info.attrs = attrbuf;
 598         genl_info_net_set(&info, net);
 599         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 600
 601         if (family->pre_doit) {
 602                 err = family->pre_doit(ops, skb, &info);
 603                 if (err)
 604                         goto out;
 605         }
 606
 607         err = ops->doit(skb, &info);
 608
 609         if (family->post_doit)
 610                 family->post_doit(ops, skb, &info);
 611
 612 out:
 613         if (family->parallel_ops)
 614                 kfree(attrbuf);
 615
 616         return err;
 617 }
 618
 619 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 620 {
 621         struct genl_family *family;
 622         int err;
 623
 624         family = genl_family_find_byid(nlh->nlmsg_type);
 625         if (family == NULL)
 626                 return -ENOENT;
 627
 628         if (!family->parallel_ops)
 629                 genl_lock();
 630
 631         err = genl_family_rcv_msg(family, skb, nlh);
 632
 633         if (!family->parallel_ops)
 634                 genl_unlock();
 635
 636         return err;
 637 }
 638
 639 static void genl_rcv(struct sk_buff *skb)
 640 {
 641         down_read(&cb_lock);
 642         netlink_rcv_skb(skb, &genl_rcv_msg);
 643         up_read(&cb_lock);
 644 }
 645
 646 /**************************************************************************
 647  * Controller
 648  **************************************************************************/
 649
 650 static struct genl_family genl_ctrl = {
 651         .id = GENL_ID_CTRL,
 652         .name = "nlctrl",
 653         .version = 0x2,
 654         .maxattr = CTRL_ATTR_MAX,
 655         .netnsok = true,
 656 };
 657
 658 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 659                           u32 flags, struct sk_buff *skb, u8 cmd)
 660 {
 661         void *hdr;
 662
 663         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 664         if (hdr == NULL)
 665                 return -1;
 666
 667         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 668             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 669             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 670             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 671             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 672                 goto nla_put_failure;
 673
 674         if (!list_empty(&family->ops_list)) {
 675                 struct nlattr *nla_ops;
 676                 struct genl_ops *ops;
 677                 int idx = 1;
 678
 679                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 680                 if (nla_ops == NULL)
 681                         goto nla_put_failure;
 682
 683                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 684                         struct nlattr *nest;
 685
 686                         nest = nla_nest_start(skb, idx++);
 687                         if (nest == NULL)
 688                                 goto nla_put_failure;
 689
 690                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
 691                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags))
 692                                 goto nla_put_failure;
 693
 694                         nla_nest_end(skb, nest);
 695                 }
 696
 697                 nla_nest_end(skb, nla_ops);
 698         }
 699
 700         if (!list_empty(&family->mcast_groups)) {
 701                 struct genl_multicast_group *grp;
 702                 struct nlattr *nla_grps;
 703                 int idx = 1;
 704
 705                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 706                 if (nla_grps == NULL)
 707                         goto nla_put_failure;
 708
 709                 list_for_each_entry(grp, &family->mcast_groups, list) {
 710                         struct nlattr *nest;
 711
 712                         nest = nla_nest_start(skb, idx++);
 713                         if (nest == NULL)
 714                                 goto nla_put_failure;
 715
 716                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 717                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 718                                            grp->name))
 719                                 goto nla_put_failure;
 720
 721                         nla_nest_end(skb, nest);
 722                 }
 723                 nla_nest_end(skb, nla_grps);
 724         }
 725
 726         return genlmsg_end(skb, hdr);
 727
 728 nla_put_failure:
 729         genlmsg_cancel(skb, hdr);
 730         return -EMSGSIZE;
 731 }
 732
 733 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
 734                                 u32 seq, u32 flags, struct sk_buff *skb,
 735                                 u8 cmd)
 736 {
 737         void *hdr;
 738         struct nlattr *nla_grps;
 739         struct nlattr *nest;
 740
 741         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 742         if (hdr == NULL)
 743                 return -1;
 744
 745         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
 746             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
 747                 goto nla_put_failure;
 748
 749         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 750         if (nla_grps == NULL)
 751                 goto nla_put_failure;
 752
 753         nest = nla_nest_start(skb, 1);
 754         if (nest == NULL)
 755                 goto nla_put_failure;
 756
 757         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 758             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 759                            grp->name))
 760                 goto nla_put_failure;
 761
 762         nla_nest_end(skb, nest);
 763         nla_nest_end(skb, nla_grps);
 764
 765         return genlmsg_end(skb, hdr);
 766
 767 nla_put_failure:
 768         genlmsg_cancel(skb, hdr);
 769         return -EMSGSIZE;
 770 }
 771
 772 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 773 {
 774
 775         int i, n = 0;
 776         struct genl_family *rt;
 777         struct net *net = sock_net(skb->sk);
 778         int chains_to_skip = cb->args[0];
 779         int fams_to_skip = cb->args[1];
 780
 781         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 782                 n = 0;
 783                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 784                         if (!rt->netnsok && !net_eq(net, &init_net))
 785                                 continue;
 786                         if (++n < fams_to_skip)
 787                                 continue;
 788                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 789                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 790                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 791                                 goto errout;
 792                 }
 793
 794                 fams_to_skip = 0;
 795         }
 796
 797 errout:
 798         cb->args[0] = i;
 799         cb->args[1] = n;
 800
 801         return skb->len;
 802 }
 803
 804 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 805                                              u32 portid, int seq, u8 cmd)
 806 {
 807         struct sk_buff *skb;
 808         int err;
 809
 810         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 811         if (skb == NULL)
 812                 return ERR_PTR(-ENOBUFS);
 813
 814         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 815         if (err < 0) {
 816                 nlmsg_free(skb);
 817                 return ERR_PTR(err);
 818         }
 819
 820         return skb;
 821 }
 822
 823 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 824                                             u32 portid, int seq, u8 cmd)
 825 {
 826         struct sk_buff *skb;
 827         int err;
 828
 829         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 830         if (skb == NULL)
 831                 return ERR_PTR(-ENOBUFS);
 832
 833         err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd);
 834         if (err < 0) {
 835                 nlmsg_free(skb);
 836                 return ERR_PTR(err);
 837         }
 838
 839         return skb;
 840 }
 841
 842 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 843         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 844         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 845                                     .len = GENL_NAMSIZ - 1 },
 846 };
 847
 848 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 849 {
 850         struct sk_buff *msg;
 851         struct genl_family *res = NULL;
 852         int err = -EINVAL;
 853
 854         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 855                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 856                 res = genl_family_find_byid(id);
 857                 err = -ENOENT;
 858         }
 859
 860         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 861                 char *name;
 862
 863                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 864                 res = genl_family_find_byname(name);
 865 #ifdef CONFIG_MODULES
 866                 if (res == NULL) {
 867                         genl_unlock();
 868                         up_read(&cb_lock);
 869                         request_module("net-pf-%d-proto-%d-family-%s",
 870                                        PF_NETLINK, NETLINK_GENERIC, name);
 871                         down_read(&cb_lock);
 872                         genl_lock();
 873                         res = genl_family_find_byname(name);
 874                 }
 875 #endif
 876                 err = -ENOENT;
 877         }
 878
 879         if (res == NULL)
 880                 return err;
 881
 882         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 883                 /* family doesn't exist here */
 884                 return -ENOENT;
 885         }
 886
 887         msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
 888                                     CTRL_CMD_NEWFAMILY);
 889         if (IS_ERR(msg))
 890                 return PTR_ERR(msg);
 891
 892         return genlmsg_reply(msg, info);
 893 }
 894
 895 static int genl_ctrl_event(int event, void *data)
 896 {
 897         struct sk_buff *msg;
 898         struct genl_family *family;
 899         struct genl_multicast_group *grp;
 900
 901         /* genl is still initialising */
 902         if (!init_net.genl_sock)
 903                 return 0;
 904
 905         switch (event) {
 906         case CTRL_CMD_NEWFAMILY:
 907         case CTRL_CMD_DELFAMILY:
 908                 family = data;
 909                 msg = ctrl_build_family_msg(family, 0, 0, event);
 910                 break;
 911         case CTRL_CMD_NEWMCAST_GRP:
 912         case CTRL_CMD_DELMCAST_GRP:
 913                 grp = data;
 914                 family = grp->family;
 915                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 916                 break;
 917         default:
 918                 return -EINVAL;
 919         }
 920
 921         if (IS_ERR(msg))
 922                 return PTR_ERR(msg);
 923
 924         if (!family->netnsok) {
 925                 genlmsg_multicast_netns(&init_net, msg, 0,
 926                                         GENL_ID_CTRL, GFP_KERNEL);
 927         } else {
 928                 rcu_read_lock();
 929                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
 930                 rcu_read_unlock();
 931         }
 932
 933         return 0;
 934 }
 935
 936 static struct genl_ops genl_ctrl_ops = {
 937         .cmd            = CTRL_CMD_GETFAMILY,
 938         .doit           = ctrl_getfamily,
 939         .dumpit         = ctrl_dumpfamily,
 940         .policy         = ctrl_policy,
 941 };
 942
 943 static struct genl_multicast_group notify_grp = {
 944         .name           = "notify",
 945 };
 946
 947 static int __net_init genl_pernet_init(struct net *net)
 948 {
 949         struct netlink_kernel_cfg cfg = {
 950                 .input          = genl_rcv,
 951                 .flags          = NL_CFG_F_NONROOT_RECV,
 952         };
 953
 954         /* we'll bump the group number right afterwards */
 955         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
 956
 957         if (!net->genl_sock && net_eq(net, &init_net))
 958                 panic("GENL: Cannot initialize generic netlink\n");
 959
 960         if (!net->genl_sock)
 961                 return -ENOMEM;
 962
 963         return 0;
 964 }
 965
 966 static void __net_exit genl_pernet_exit(struct net *net)
 967 {
 968         netlink_kernel_release(net->genl_sock);
 969         net->genl_sock = NULL;
 970 }
 971
 972 static struct pernet_operations genl_pernet_ops = {
 973         .init = genl_pernet_init,
 974         .exit = genl_pernet_exit,
 975 };
 976
 977 static int __init genl_init(void)
 978 {
 979         int i, err;
 980
 981         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 982                 INIT_LIST_HEAD(&family_ht[i]);
 983
 984         err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
 985         if (err < 0)
 986                 goto problem;
 987
 988         err = register_pernet_subsys(&genl_pernet_ops);
 989         if (err)
 990                 goto problem;
 991
 992         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 993         if (err < 0)
 994                 goto problem;
 995
 996         return 0;
 997
 998 problem:
 999         panic("GENL: Cannot register controller: %d\n", err);
1000 }
1001
1002 subsys_initcall(genl_init);
1003
1004 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1005                          gfp_t flags)
1006 {
1007         struct sk_buff *tmp;
1008         struct net *net, *prev = NULL;
1009         int err;
1010
1011         for_each_net_rcu(net) {
1012                 if (prev) {
1013                         tmp = skb_clone(skb, flags);
1014                         if (!tmp) {
1015                                 err = -ENOMEM;
1016                                 goto error;
1017                         }
1018                         err = nlmsg_multicast(prev->genl_sock, tmp,
1019                                               portid, group, flags);
1020                         if (err)
1021                                 goto error;
1022                 }
1023
1024                 prev = net;
1025         }
1026
1027         return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1028  error:
1029         kfree_skb(skb);
1030         return err;
1031 }
1032
1033 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group,
1034                             gfp_t flags)
1035 {
1036         return genlmsg_mcast(skb, portid, group, flags);
1037 }
1038 EXPORT_SYMBOL(genlmsg_multicast_allns);
1039
1040 void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
1041                  struct nlmsghdr *nlh, gfp_t flags)
1042 {
1043         struct sock *sk = net->genl_sock;
1044         int report = 0;
1045
1046         if (nlh)
1047                 report = nlmsg_report(nlh);
1048
1049         nlmsg_notify(sk, skb, portid, group, report, flags);
1050 }
1051 EXPORT_SYMBOL(genl_notify);