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_PROVE_LOCKING
  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
 146         genl_lock();
 147
 148         /* special-case our own group */
 149         if (grp == &notify_grp)
 150                 id = GENL_ID_CTRL;
 151         else
 152                 id = find_first_zero_bit(mc_groups,
 153                                          mc_groups_longs * BITS_PER_LONG);
 154
 155
 156         if (id >= mc_groups_longs * BITS_PER_LONG) {
 157                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
 158
 159                 if (mc_groups == &mc_group_start) {
 160                         new_groups = kzalloc(nlen, GFP_KERNEL);
 161                         if (!new_groups) {
 162                                 err = -ENOMEM;
 163                                 goto out;
 164                         }
 165                         mc_groups = new_groups;
 166                         *mc_groups = mc_group_start;
 167                 } else {
 168                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
 169                         if (!new_groups) {
 170                                 err = -ENOMEM;
 171                                 goto out;
 172                         }
 173                         mc_groups = new_groups;
 174                         mc_groups[mc_groups_longs] = 0;
 175                 }
 176                 mc_groups_longs++;
 177         }
 178
 179         if (family->netnsok) {
 180                 struct net *net;
 181
 182                 netlink_table_grab();
 183                 rcu_read_lock();
 184                 for_each_net_rcu(net) {
 185                         err = __netlink_change_ngroups(net->genl_sock,
 186                                         mc_groups_longs * BITS_PER_LONG);
 187                         if (err) {
 188                                 /*
 189                                  * No need to roll back, can only fail if
 190                                  * memory allocation fails and then the
 191                                  * number of _possible_ groups has been
 192                                  * increased on some sockets which is ok.
 193                                  */
 194                                 rcu_read_unlock();
 195                                 netlink_table_ungrab();
 196                                 goto out;
 197                         }
 198                 }
 199                 rcu_read_unlock();
 200                 netlink_table_ungrab();
 201         } else {
 202                 err = netlink_change_ngroups(init_net.genl_sock,
 203                                              mc_groups_longs * BITS_PER_LONG);
 204                 if (err)
 205                         goto out;
 206         }
 207
 208         grp->id = id;
 209         set_bit(id, mc_groups);
 210         list_add_tail(&grp->list, &family->mcast_groups);
 211         grp->family = family;
 212
 213         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
 214  out:
 215         genl_unlock();
 216         return err;
 217 }
 218 EXPORT_SYMBOL(genl_register_mc_group);
 219
 220 static void __genl_unregister_mc_group(struct genl_family *family,
 221                                        struct genl_multicast_group *grp)
 222 {
 223         struct net *net;
 224         BUG_ON(grp->family != family);
 225
 226         netlink_table_grab();
 227         rcu_read_lock();
 228         for_each_net_rcu(net)
 229                 __netlink_clear_multicast_users(net->genl_sock, grp->id);
 230         rcu_read_unlock();
 231         netlink_table_ungrab();
 232
 233         clear_bit(grp->id, mc_groups);
 234         list_del(&grp->list);
 235         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 236         grp->id = 0;
 237         grp->family = NULL;
 238 }
 239
 240 /**
 241  * genl_unregister_mc_group - unregister a multicast group
 242  *
 243  * Unregisters the specified multicast group and notifies userspace
 244  * about it. All current listeners on the group are removed.
 245  *
 246  * Note: It is not necessary to unregister all multicast groups before
 247  *       unregistering the family, unregistering the family will cause
 248  *       all assigned multicast groups to be unregistered automatically.
 249  *
 250  * @family: Generic netlink family the group belongs to.
 251  * @grp: The group to unregister, must have been registered successfully
 252  *       previously.
 253  */
 254 void genl_unregister_mc_group(struct genl_family *family,
 255                               struct genl_multicast_group *grp)
 256 {
 257         genl_lock();
 258         __genl_unregister_mc_group(family, grp);
 259         genl_unlock();
 260 }
 261 EXPORT_SYMBOL(genl_unregister_mc_group);
 262
 263 static void genl_unregister_mc_groups(struct genl_family *family)
 264 {
 265         struct genl_multicast_group *grp, *tmp;
 266
 267         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 268                 __genl_unregister_mc_group(family, grp);
 269 }
 270
 271 /**
 272  * genl_register_ops - register generic netlink operations
 273  * @family: generic netlink family
 274  * @ops: operations to be registered
 275  *
 276  * Registers the specified operations and assigns them to the specified
 277  * family. Either a doit or dumpit callback must be specified or the
 278  * operation will fail. Only one operation structure per command
 279  * identifier may be registered.
 280  *
 281  * See include/net/genetlink.h for more documenation on the operations
 282  * structure.
 283  *
 284  * Returns 0 on success or a negative error code.
 285  */
 286 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();
 306         list_add_tail(&ops->ops_list, &family->ops_list);
 307         genl_unlock();
 308
 309         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 310         err = 0;
 311 errout:
 312         return err;
 313 }
 314 EXPORT_SYMBOL(genl_register_ops);
 315
 316 /**
 317  * genl_unregister_ops - unregister generic netlink operations
 318  * @family: generic netlink family
 319  * @ops: operations to be unregistered
 320  *
 321  * Unregisters the specified operations and unassigns them from the
 322  * specified family. The operation blocks until the current message
 323  * processing has finished and doesn't start again until the
 324  * unregister process has finished.
 325  *
 326  * Note: It is not necessary to unregister all operations before
 327  *       unregistering the family, unregistering the family will cause
 328  *       all assigned operations to be unregistered automatically.
 329  *
 330  * Returns 0 on success or a negative error code.
 331  */
 332 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 333 {
 334         struct genl_ops *rc;
 335
 336         genl_lock();
 337         list_for_each_entry(rc, &family->ops_list, ops_list) {
 338                 if (rc == ops) {
 339                         list_del(&ops->ops_list);
 340                         genl_unlock();
 341                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
 342                         return 0;
 343                 }
 344         }
 345         genl_unlock();
 346
 347         return -ENOENT;
 348 }
 349 EXPORT_SYMBOL(genl_unregister_ops);
 350
 351 /**
 352  * genl_register_family - register a generic netlink family
 353  * @family: generic netlink family
 354  *
 355  * Registers the specified family after validating it first. Only one
 356  * family may be registered with the same family name or identifier.
 357  * The family id may equal GENL_ID_GENERATE causing an unique id to
 358  * be automatically generated and assigned.
 359  *
 360  * Return 0 on success or a negative error code.
 361  */
 362 int genl_register_family(struct genl_family *family)
 363 {
 364         int err = -EINVAL;
 365
 366         if (family->id && family->id < GENL_MIN_ID)
 367                 goto errout;
 368
 369         if (family->id > GENL_MAX_ID)
 370                 goto errout;
 371
 372         INIT_LIST_HEAD(&family->ops_list);
 373         INIT_LIST_HEAD(&family->mcast_groups);
 374
 375         genl_lock();
 376
 377         if (genl_family_find_byname(family->name)) {
 378                 err = -EEXIST;
 379                 goto errout_locked;
 380         }
 381
 382         if (family->id == GENL_ID_GENERATE) {
 383                 u16 newid = genl_generate_id();
 384
 385                 if (!newid) {
 386                         err = -ENOMEM;
 387                         goto errout_locked;
 388                 }
 389
 390                 family->id = newid;
 391         } else if (genl_family_find_byid(family->id)) {
 392                 err = -EEXIST;
 393                 goto errout_locked;
 394         }
 395
 396         if (family->maxattr) {
 397                 family->attrbuf = kmalloc((family->maxattr+1) *
 398                                         sizeof(struct nlattr *), GFP_KERNEL);
 399                 if (family->attrbuf == NULL) {
 400                         err = -ENOMEM;
 401                         goto errout_locked;
 402                 }
 403         } else
 404                 family->attrbuf = NULL;
 405
 406         list_add_tail(&family->family_list, genl_family_chain(family->id));
 407         genl_unlock();
 408
 409         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 410
 411         return 0;
 412
 413 errout_locked:
 414         genl_unlock();
 415 errout:
 416         return err;
 417 }
 418 EXPORT_SYMBOL(genl_register_family);
 419
 420 /**
 421  * genl_register_family_with_ops - register a generic netlink family
 422  * @family: generic netlink family
 423  * @ops: operations to be registered
 424  * @n_ops: number of elements to register
 425  *
 426  * Registers the specified family and operations from the specified table.
 427  * Only one family may be registered with the same family name or identifier.
 428  *
 429  * The family id may equal GENL_ID_GENERATE causing an unique id to
 430  * be automatically generated and assigned.
 431  *
 432  * Either a doit or dumpit callback must be specified for every registered
 433  * operation or the function will fail. Only one operation structure per
 434  * command identifier may be registered.
 435  *
 436  * See include/net/genetlink.h for more documenation on the operations
 437  * structure.
 438  *
 439  * This is equivalent to calling genl_register_family() followed by
 440  * genl_register_ops() for every operation entry in the table taking
 441  * care to unregister the family on error path.
 442  *
 443  * Return 0 on success or a negative error code.
 444  */
 445 int genl_register_family_with_ops(struct genl_family *family,
 446         struct genl_ops *ops, size_t n_ops)
 447 {
 448         int err, i;
 449
 450         err = genl_register_family(family);
 451         if (err)
 452                 return err;
 453
 454         for (i = 0; i < n_ops; ++i, ++ops) {
 455                 err = genl_register_ops(family, ops);
 456                 if (err)
 457                         goto err_out;
 458         }
 459         return 0;
 460 err_out:
 461         genl_unregister_family(family);
 462         return err;
 463 }
 464 EXPORT_SYMBOL(genl_register_family_with_ops);
 465
 466 /**
 467  * genl_unregister_family - unregister generic netlink family
 468  * @family: generic netlink family
 469  *
 470  * Unregisters the specified family.
 471  *
 472  * Returns 0 on success or a negative error code.
 473  */
 474 int genl_unregister_family(struct genl_family *family)
 475 {
 476         struct genl_family *rc;
 477
 478         genl_lock();
 479
 480         genl_unregister_mc_groups(family);
 481
 482         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 483                 if (family->id != rc->id || strcmp(rc->name, family->name))
 484                         continue;
 485
 486                 list_del(&rc->family_list);
 487                 INIT_LIST_HEAD(&family->ops_list);
 488                 genl_unlock();
 489
 490                 kfree(family->attrbuf);
 491                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 492                 return 0;
 493         }
 494
 495         genl_unlock();
 496
 497         return -ENOENT;
 498 }
 499 EXPORT_SYMBOL(genl_unregister_family);
 500
 501 /**
 502  * genlmsg_put - Add generic netlink header to netlink message
 503  * @skb: socket buffer holding the message
 504  * @pid: netlink pid the message is addressed to
 505  * @seq: sequence number (usually the one of the sender)
 506  * @family: generic netlink family
 507  * @flags netlink message flags
 508  * @cmd: generic netlink command
 509  *
 510  * Returns pointer to user specific header
 511  */
 512 void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 513                                 struct genl_family *family, int flags, u8 cmd)
 514 {
 515         struct nlmsghdr *nlh;
 516         struct genlmsghdr *hdr;
 517
 518         nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN +
 519                         family->hdrsize, flags);
 520         if (nlh == NULL)
 521                 return NULL;
 522
 523         hdr = nlmsg_data(nlh);
 524         hdr->cmd = cmd;
 525         hdr->version = family->version;
 526         hdr->reserved = 0;
 527
 528         return (char *) hdr + GENL_HDRLEN;
 529 }
 530 EXPORT_SYMBOL(genlmsg_put);
 531
 532 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 533 {
 534         struct genl_ops *ops;
 535         struct genl_family *family;
 536         struct net *net = sock_net(skb->sk);
 537         struct genl_info info;
 538         struct genlmsghdr *hdr = nlmsg_data(nlh);
 539         int hdrlen, err;
 540
 541         family = genl_family_find_byid(nlh->nlmsg_type);
 542         if (family == NULL)
 543                 return -ENOENT;
 544
 545         /* this family doesn't exist in this netns */
 546         if (!family->netnsok && !net_eq(net, &init_net))
 547                 return -ENOENT;
 548
 549         hdrlen = GENL_HDRLEN + family->hdrsize;
 550         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 551                 return -EINVAL;
 552
 553         ops = genl_get_cmd(hdr->cmd, family);
 554         if (ops == NULL)
 555                 return -EOPNOTSUPP;
 556
 557         if ((ops->flags & GENL_ADMIN_PERM) &&
 558             !capable(CAP_NET_ADMIN))
 559                 return -EPERM;
 560
 561         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 562                 if (ops->dumpit == NULL)
 563                         return -EOPNOTSUPP;
 564
 565                 genl_unlock();
 566                 err = netlink_dump_start(net->genl_sock, skb, nlh,
 567                                          ops->dumpit, ops->done, 0);
 568                 genl_lock();
 569                 return err;
 570         }
 571
 572         if (ops->doit == NULL)
 573                 return -EOPNOTSUPP;
 574
 575         if (family->attrbuf) {
 576                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 577                                   ops->policy);
 578                 if (err < 0)
 579                         return err;
 580         }
 581
 582         info.snd_seq = nlh->nlmsg_seq;
 583         info.snd_pid = NETLINK_CB(skb).pid;
 584         info.nlhdr = nlh;
 585         info.genlhdr = nlmsg_data(nlh);
 586         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 587         info.attrs = family->attrbuf;
 588         genl_info_net_set(&info, net);
 589         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 590
 591         if (family->pre_doit) {
 592                 err = family->pre_doit(ops, skb, &info);
 593                 if (err)
 594                         return err;
 595         }
 596
 597         err = ops->doit(skb, &info);
 598
 599         if (family->post_doit)
 600                 family->post_doit(ops, skb, &info);
 601
 602         return err;
 603 }
 604
 605 static void genl_rcv(struct sk_buff *skb)
 606 {
 607         genl_lock();
 608         netlink_rcv_skb(skb, &genl_rcv_msg);
 609         genl_unlock();
 610 }
 611
 612 /**************************************************************************
 613  * Controller
 614  **************************************************************************/
 615
 616 static struct genl_family genl_ctrl = {
 617         .id = GENL_ID_CTRL,
 618         .name = "nlctrl",
 619         .version = 0x2,
 620         .maxattr = CTRL_ATTR_MAX,
 621         .netnsok = true,
 622 };
 623
 624 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 625                           u32 flags, struct sk_buff *skb, u8 cmd)
 626 {
 627         void *hdr;
 628
 629         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 630         if (hdr == NULL)
 631                 return -1;
 632
 633         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 634         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 635         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 636         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 637         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 638
 639         if (!list_empty(&family->ops_list)) {
 640                 struct nlattr *nla_ops;
 641                 struct genl_ops *ops;
 642                 int idx = 1;
 643
 644                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 645                 if (nla_ops == NULL)
 646                         goto nla_put_failure;
 647
 648                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 649                         struct nlattr *nest;
 650
 651                         nest = nla_nest_start(skb, idx++);
 652                         if (nest == NULL)
 653                                 goto nla_put_failure;
 654
 655                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 656                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 657
 658                         nla_nest_end(skb, nest);
 659                 }
 660
 661                 nla_nest_end(skb, nla_ops);
 662         }
 663
 664         if (!list_empty(&family->mcast_groups)) {
 665                 struct genl_multicast_group *grp;
 666                 struct nlattr *nla_grps;
 667                 int idx = 1;
 668
 669                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 670                 if (nla_grps == NULL)
 671                         goto nla_put_failure;
 672
 673                 list_for_each_entry(grp, &family->mcast_groups, list) {
 674                         struct nlattr *nest;
 675
 676                         nest = nla_nest_start(skb, idx++);
 677                         if (nest == NULL)
 678                                 goto nla_put_failure;
 679
 680                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 681                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 682                                        grp->name);
 683
 684                         nla_nest_end(skb, nest);
 685                 }
 686                 nla_nest_end(skb, nla_grps);
 687         }
 688
 689         return genlmsg_end(skb, hdr);
 690
 691 nla_put_failure:
 692         genlmsg_cancel(skb, hdr);
 693         return -EMSGSIZE;
 694 }
 695
 696 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 697                                 u32 seq, u32 flags, struct sk_buff *skb,
 698                                 u8 cmd)
 699 {
 700         void *hdr;
 701         struct nlattr *nla_grps;
 702         struct nlattr *nest;
 703
 704         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 705         if (hdr == NULL)
 706                 return -1;
 707
 708         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 709         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 710
 711         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 712         if (nla_grps == NULL)
 713                 goto nla_put_failure;
 714
 715         nest = nla_nest_start(skb, 1);
 716         if (nest == NULL)
 717                 goto nla_put_failure;
 718
 719         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 720         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 721                        grp->name);
 722
 723         nla_nest_end(skb, nest);
 724         nla_nest_end(skb, nla_grps);
 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_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 734 {
 735
 736         int i, n = 0;
 737         struct genl_family *rt;
 738         struct net *net = sock_net(skb->sk);
 739         int chains_to_skip = cb->args[0];
 740         int fams_to_skip = cb->args[1];
 741
 742         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 743                 n = 0;
 744                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 745                         if (!rt->netnsok && !net_eq(net, &init_net))
 746                                 continue;
 747                         if (++n < fams_to_skip)
 748                                 continue;
 749                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
 750                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 751                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 752                                 goto errout;
 753                 }
 754
 755                 fams_to_skip = 0;
 756         }
 757
 758 errout:
 759         cb->args[0] = i;
 760         cb->args[1] = n;
 761
 762         return skb->len;
 763 }
 764
 765 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 766                                              u32 pid, int seq, u8 cmd)
 767 {
 768         struct sk_buff *skb;
 769         int err;
 770
 771         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 772         if (skb == NULL)
 773                 return ERR_PTR(-ENOBUFS);
 774
 775         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 776         if (err < 0) {
 777                 nlmsg_free(skb);
 778                 return ERR_PTR(err);
 779         }
 780
 781         return skb;
 782 }
 783
 784 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 785                                             u32 pid, int seq, u8 cmd)
 786 {
 787         struct sk_buff *skb;
 788         int err;
 789
 790         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 791         if (skb == NULL)
 792                 return ERR_PTR(-ENOBUFS);
 793
 794         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 795         if (err < 0) {
 796                 nlmsg_free(skb);
 797                 return ERR_PTR(err);
 798         }
 799
 800         return skb;
 801 }
 802
 803 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 804         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 805         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 806                                     .len = GENL_NAMSIZ - 1 },
 807 };
 808
 809 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 810 {
 811         struct sk_buff *msg;
 812         struct genl_family *res = NULL;
 813         int err = -EINVAL;
 814
 815         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 816                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 817                 res = genl_family_find_byid(id);
 818                 err = -ENOENT;
 819         }
 820
 821         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 822                 char *name;
 823
 824                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 825                 res = genl_family_find_byname(name);
 826 #ifdef CONFIG_MODULES
 827                 if (res == NULL) {
 828                         genl_unlock();
 829                         request_module("net-pf-%d-proto-%d-type-%s",
 830                                        PF_NETLINK, NETLINK_GENERIC, name);
 831                         genl_lock();
 832                         res = genl_family_find_byname(name);
 833                 }
 834 #endif
 835                 err = -ENOENT;
 836         }
 837
 838         if (res == NULL)
 839                 return err;
 840
 841         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 842                 /* family doesn't exist here */
 843                 return -ENOENT;
 844         }
 845
 846         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 847                                     CTRL_CMD_NEWFAMILY);
 848         if (IS_ERR(msg))
 849                 return PTR_ERR(msg);
 850
 851         return genlmsg_reply(msg, info);
 852 }
 853
 854 static int genl_ctrl_event(int event, void *data)
 855 {
 856         struct sk_buff *msg;
 857         struct genl_family *family;
 858         struct genl_multicast_group *grp;
 859
 860         /* genl is still initialising */
 861         if (!init_net.genl_sock)
 862                 return 0;
 863
 864         switch (event) {
 865         case CTRL_CMD_NEWFAMILY:
 866         case CTRL_CMD_DELFAMILY:
 867                 family = data;
 868                 msg = ctrl_build_family_msg(family, 0, 0, event);
 869                 break;
 870         case CTRL_CMD_NEWMCAST_GRP:
 871         case CTRL_CMD_DELMCAST_GRP:
 872                 grp = data;
 873                 family = grp->family;
 874                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 875                 break;
 876         default:
 877                 return -EINVAL;
 878         }
 879
 880         if (IS_ERR(msg))
 881                 return PTR_ERR(msg);
 882
 883         if (!family->netnsok) {
 884                 genlmsg_multicast_netns(&init_net, msg, 0,
 885                                         GENL_ID_CTRL, GFP_KERNEL);
 886         } else {
 887                 rcu_read_lock();
 888                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
 889                 rcu_read_unlock();
 890         }
 891
 892         return 0;
 893 }
 894
 895 static struct genl_ops genl_ctrl_ops = {
 896         .cmd            = CTRL_CMD_GETFAMILY,
 897         .doit           = ctrl_getfamily,
 898         .dumpit         = ctrl_dumpfamily,
 899         .policy         = ctrl_policy,
 900 };
 901
 902 static struct genl_multicast_group notify_grp = {
 903         .name           = "notify",
 904 };
 905
 906 static int __net_init genl_pernet_init(struct net *net)
 907 {
 908         /* we'll bump the group number right afterwards */
 909         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
 910                                                genl_rcv, &genl_mutex,
 911                                                THIS_MODULE);
 912
 913         if (!net->genl_sock && net_eq(net, &init_net))
 914                 panic("GENL: Cannot initialize generic netlink\n");
 915
 916         if (!net->genl_sock)
 917                 return -ENOMEM;
 918
 919         return 0;
 920 }
 921
 922 static void __net_exit genl_pernet_exit(struct net *net)
 923 {
 924         netlink_kernel_release(net->genl_sock);
 925         net->genl_sock = NULL;
 926 }
 927
 928 static struct pernet_operations genl_pernet_ops = {
 929         .init = genl_pernet_init,
 930         .exit = genl_pernet_exit,
 931 };
 932
 933 static int __init genl_init(void)
 934 {
 935         int i, err;
 936
 937         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 938                 INIT_LIST_HEAD(&family_ht[i]);
 939
 940         err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
 941         if (err < 0)
 942                 goto problem;
 943
 944         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 945
 946         err = register_pernet_subsys(&genl_pernet_ops);
 947         if (err)
 948                 goto problem;
 949
 950         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 951         if (err < 0)
 952                 goto problem;
 953
 954         return 0;
 955
 956 problem:
 957         panic("GENL: Cannot register controller: %d\n", err);
 958 }
 959
 960 subsys_initcall(genl_init);
 961
 962 static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
 963                          gfp_t flags)
 964 {
 965         struct sk_buff *tmp;
 966         struct net *net, *prev = NULL;
 967         int err;
 968
 969         for_each_net_rcu(net) {
 970                 if (prev) {
 971                         tmp = skb_clone(skb, flags);
 972                         if (!tmp) {
 973                                 err = -ENOMEM;
 974                                 goto error;
 975                         }
 976                         err = nlmsg_multicast(prev->genl_sock, tmp,
 977                                               pid, group, flags);
 978                         if (err)
 979                                 goto error;
 980                 }
 981
 982                 prev = net;
 983         }
 984
 985         return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
 986  error:
 987         kfree_skb(skb);
 988         return err;
 989 }
 990
 991 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
 992                             gfp_t flags)
 993 {
 994         return genlmsg_mcast(skb, pid, group, flags);
 995 }
 996 EXPORT_SYMBOL(genlmsg_multicast_allns);
 997
 998 void genl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group,
 999                  struct nlmsghdr *nlh, gfp_t flags)
1000 {
1001         struct sock *sk = net->genl_sock;
1002         int report = 0;
1003
1004         if (nlh)
1005                 report = nlmsg_report(nlh);
1006
1007         nlmsg_notify(sk, skb, pid, group, report, flags);
1008 }
1009 EXPORT_SYMBOL(genl_notify);