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 const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
 110 {
 111         int i;
 112
 113         for (i = 0; i < family->n_ops; i++)
 114                 if (family->ops[i].cmd == cmd)
 115                         return &family->ops[i];
 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_validate_ops(struct genl_family *family)
 287 {
 288         const struct genl_ops *ops = family->ops;
 289         unsigned int n_ops = family->n_ops;
 290         int i, j;
 291
 292         if (WARN_ON(n_ops && !ops))
 293                 return -EINVAL;
 294
 295         if (!n_ops)
 296                 return 0;
 297
 298         for (i = 0; i < n_ops; i++) {
 299                 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
 300                         return -EINVAL;
 301                 for (j = i + 1; j < n_ops; j++)
 302                         if (ops[i].cmd == ops[j].cmd)
 303                                 return -EINVAL;
 304         }
 305
 306         /* family is not registered yet, so no locking needed */
 307         family->ops = ops;
 308         family->n_ops = n_ops;
 309
 310         return 0;
 311 }
 312
 313 /**
 314  * __genl_register_family - register a generic netlink family
 315  * @family: generic netlink family
 316  *
 317  * Registers the specified family after validating it first. Only one
 318  * family may be registered with the same family name or identifier.
 319  * The family id may equal GENL_ID_GENERATE causing an unique id to
 320  * be automatically generated and assigned.
 321  *
 322  * The family's ops array must already be assigned, you can use the
 323  * genl_register_family_with_ops() helper function.
 324  *
 325  * Return 0 on success or a negative error code.
 326  */
 327 int __genl_register_family(struct genl_family *family)
 328 {
 329         int err = -EINVAL;
 330
 331         if (family->id && family->id < GENL_MIN_ID)
 332                 goto errout;
 333
 334         if (family->id > GENL_MAX_ID)
 335                 goto errout;
 336
 337         err = genl_validate_ops(family);
 338         if (err)
 339                 return err;
 340
 341         INIT_LIST_HEAD(&family->mcast_groups);
 342
 343         genl_lock_all();
 344
 345         if (genl_family_find_byname(family->name)) {
 346                 err = -EEXIST;
 347                 goto errout_locked;
 348         }
 349
 350         if (family->id == GENL_ID_GENERATE) {
 351                 u16 newid = genl_generate_id();
 352
 353                 if (!newid) {
 354                         err = -ENOMEM;
 355                         goto errout_locked;
 356                 }
 357
 358                 family->id = newid;
 359         } else if (genl_family_find_byid(family->id)) {
 360                 err = -EEXIST;
 361                 goto errout_locked;
 362         }
 363
 364         if (family->maxattr && !family->parallel_ops) {
 365                 family->attrbuf = kmalloc((family->maxattr+1) *
 366                                         sizeof(struct nlattr *), GFP_KERNEL);
 367                 if (family->attrbuf == NULL) {
 368                         err = -ENOMEM;
 369                         goto errout_locked;
 370                 }
 371         } else
 372                 family->attrbuf = NULL;
 373
 374         list_add_tail(&family->family_list, genl_family_chain(family->id));
 375         genl_unlock_all();
 376
 377         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 378
 379         return 0;
 380
 381 errout_locked:
 382         genl_unlock_all();
 383 errout:
 384         return err;
 385 }
 386 EXPORT_SYMBOL(__genl_register_family);
 387
 388 /**
 389  * genl_unregister_family - unregister generic netlink family
 390  * @family: generic netlink family
 391  *
 392  * Unregisters the specified family.
 393  *
 394  * Returns 0 on success or a negative error code.
 395  */
 396 int genl_unregister_family(struct genl_family *family)
 397 {
 398         struct genl_family *rc;
 399
 400         genl_lock_all();
 401
 402         genl_unregister_mc_groups(family);
 403
 404         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 405                 if (family->id != rc->id || strcmp(rc->name, family->name))
 406                         continue;
 407
 408                 list_del(&rc->family_list);
 409                 family->n_ops = 0;
 410                 genl_unlock_all();
 411
 412                 kfree(family->attrbuf);
 413                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 414                 return 0;
 415         }
 416
 417         genl_unlock_all();
 418
 419         return -ENOENT;
 420 }
 421 EXPORT_SYMBOL(genl_unregister_family);
 422
 423 /**
 424  * genlmsg_put - Add generic netlink header to netlink message
 425  * @skb: socket buffer holding the message
 426  * @portid: netlink portid the message is addressed to
 427  * @seq: sequence number (usually the one of the sender)
 428  * @family: generic netlink family
 429  * @flags: netlink message flags
 430  * @cmd: generic netlink command
 431  *
 432  * Returns pointer to user specific header
 433  */
 434 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 435                                 struct genl_family *family, int flags, u8 cmd)
 436 {
 437         struct nlmsghdr *nlh;
 438         struct genlmsghdr *hdr;
 439
 440         nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 441                         family->hdrsize, flags);
 442         if (nlh == NULL)
 443                 return NULL;
 444
 445         hdr = nlmsg_data(nlh);
 446         hdr->cmd = cmd;
 447         hdr->version = family->version;
 448         hdr->reserved = 0;
 449
 450         return (char *) hdr + GENL_HDRLEN;
 451 }
 452 EXPORT_SYMBOL(genlmsg_put);
 453
 454 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 455 {
 456         /* our ops are always const - netlink API doesn't propagate that */
 457         const struct genl_ops *ops = cb->data;
 458         int rc;
 459
 460         genl_lock();
 461         rc = ops->dumpit(skb, cb);
 462         genl_unlock();
 463         return rc;
 464 }
 465
 466 static int genl_lock_done(struct netlink_callback *cb)
 467 {
 468         /* our ops are always const - netlink API doesn't propagate that */
 469         const struct genl_ops *ops = cb->data;
 470         int rc = 0;
 471
 472         if (ops->done) {
 473                 genl_lock();
 474                 rc = ops->done(cb);
 475                 genl_unlock();
 476         }
 477         return rc;
 478 }
 479
 480 static int genl_family_rcv_msg(struct genl_family *family,
 481                                struct sk_buff *skb,
 482                                struct nlmsghdr *nlh)
 483 {
 484         const struct genl_ops *ops;
 485         struct net *net = sock_net(skb->sk);
 486         struct genl_info info;
 487         struct genlmsghdr *hdr = nlmsg_data(nlh);
 488         struct nlattr **attrbuf;
 489         int hdrlen, err;
 490
 491         /* this family doesn't exist in this netns */
 492         if (!family->netnsok && !net_eq(net, &init_net))
 493                 return -ENOENT;
 494
 495         hdrlen = GENL_HDRLEN + family->hdrsize;
 496         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 497                 return -EINVAL;
 498
 499         ops = genl_get_cmd(hdr->cmd, family);
 500         if (ops == NULL)
 501                 return -EOPNOTSUPP;
 502
 503         if ((ops->flags & GENL_ADMIN_PERM) &&
 504             !capable(CAP_NET_ADMIN))
 505                 return -EPERM;
 506
 507         if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
 508                 int rc;
 509
 510                 if (ops->dumpit == NULL)
 511                         return -EOPNOTSUPP;
 512
 513                 if (!family->parallel_ops) {
 514                         struct netlink_dump_control c = {
 515                                 .module = family->module,
 516                                 /* we have const, but the netlink API doesn't */
 517                                 .data = (void *)ops,
 518                                 .dump = genl_lock_dumpit,
 519                                 .done = genl_lock_done,
 520                         };
 521
 522                         genl_unlock();
 523                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 524                         genl_lock();
 525
 526                 } else {
 527                         struct netlink_dump_control c = {
 528                                 .module = family->module,
 529                                 .dump = ops->dumpit,
 530                                 .done = ops->done,
 531                         };
 532
 533                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 534                 }
 535
 536                 return rc;
 537         }
 538
 539         if (ops->doit == NULL)
 540                 return -EOPNOTSUPP;
 541
 542         if (family->maxattr && family->parallel_ops) {
 543                 attrbuf = kmalloc((family->maxattr+1) *
 544                                         sizeof(struct nlattr *), GFP_KERNEL);
 545                 if (attrbuf == NULL)
 546                         return -ENOMEM;
 547         } else
 548                 attrbuf = family->attrbuf;
 549
 550         if (attrbuf) {
 551                 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
 552                                   ops->policy);
 553                 if (err < 0)
 554                         goto out;
 555         }
 556
 557         info.snd_seq = nlh->nlmsg_seq;
 558         info.snd_portid = NETLINK_CB(skb).portid;
 559         info.nlhdr = nlh;
 560         info.genlhdr = nlmsg_data(nlh);
 561         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 562         info.attrs = attrbuf;
 563         genl_info_net_set(&info, net);
 564         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 565
 566         if (family->pre_doit) {
 567                 err = family->pre_doit(ops, skb, &info);
 568                 if (err)
 569                         goto out;
 570         }
 571
 572         err = ops->doit(skb, &info);
 573
 574         if (family->post_doit)
 575                 family->post_doit(ops, skb, &info);
 576
 577 out:
 578         if (family->parallel_ops)
 579                 kfree(attrbuf);
 580
 581         return err;
 582 }
 583
 584 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 585 {
 586         struct genl_family *family;
 587         int err;
 588
 589         family = genl_family_find_byid(nlh->nlmsg_type);
 590         if (family == NULL)
 591                 return -ENOENT;
 592
 593         if (!family->parallel_ops)
 594                 genl_lock();
 595
 596         err = genl_family_rcv_msg(family, skb, nlh);
 597
 598         if (!family->parallel_ops)
 599                 genl_unlock();
 600
 601         return err;
 602 }
 603
 604 static void genl_rcv(struct sk_buff *skb)
 605 {
 606         down_read(&cb_lock);
 607         netlink_rcv_skb(skb, &genl_rcv_msg);
 608         up_read(&cb_lock);
 609 }
 610
 611 /**************************************************************************
 612  * Controller
 613  **************************************************************************/
 614
 615 static struct genl_family genl_ctrl = {
 616         .id = GENL_ID_CTRL,
 617         .name = "nlctrl",
 618         .version = 0x2,
 619         .maxattr = CTRL_ATTR_MAX,
 620         .netnsok = true,
 621 };
 622
 623 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 624                           u32 flags, struct sk_buff *skb, u8 cmd)
 625 {
 626         void *hdr;
 627
 628         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 629         if (hdr == NULL)
 630                 return -1;
 631
 632         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 633             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 634             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 635             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 636             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 637                 goto nla_put_failure;
 638
 639         if (family->n_ops) {
 640                 struct nlattr *nla_ops;
 641                 int i;
 642
 643                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 644                 if (nla_ops == NULL)
 645                         goto nla_put_failure;
 646
 647                 for (i = 0; i < family->n_ops; i++) {
 648                         struct nlattr *nest;
 649                         const struct genl_ops *ops = &family->ops[i];
 650                         u32 op_flags = ops->flags;
 651
 652                         if (ops->dumpit)
 653                                 op_flags |= GENL_CMD_CAP_DUMP;
 654                         if (ops->doit)
 655                                 op_flags |= GENL_CMD_CAP_DO;
 656                         if (ops->policy)
 657                                 op_flags |= GENL_CMD_CAP_HASPOL;
 658
 659                         nest = nla_nest_start(skb, i + 1);
 660                         if (nest == NULL)
 661                                 goto nla_put_failure;
 662
 663                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
 664                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 665                                 goto nla_put_failure;
 666
 667                         nla_nest_end(skb, nest);
 668                 }
 669
 670                 nla_nest_end(skb, nla_ops);
 671         }
 672
 673         if (!list_empty(&family->mcast_groups)) {
 674                 struct genl_multicast_group *grp;
 675                 struct nlattr *nla_grps;
 676                 int idx = 1;
 677
 678                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 679                 if (nla_grps == NULL)
 680                         goto nla_put_failure;
 681
 682                 list_for_each_entry(grp, &family->mcast_groups, list) {
 683                         struct nlattr *nest;
 684
 685                         nest = nla_nest_start(skb, idx++);
 686                         if (nest == NULL)
 687                                 goto nla_put_failure;
 688
 689                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 690                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 691                                            grp->name))
 692                                 goto nla_put_failure;
 693
 694                         nla_nest_end(skb, nest);
 695                 }
 696                 nla_nest_end(skb, nla_grps);
 697         }
 698
 699         return genlmsg_end(skb, hdr);
 700
 701 nla_put_failure:
 702         genlmsg_cancel(skb, hdr);
 703         return -EMSGSIZE;
 704 }
 705
 706 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid,
 707                                 u32 seq, u32 flags, struct sk_buff *skb,
 708                                 u8 cmd)
 709 {
 710         void *hdr;
 711         struct nlattr *nla_grps;
 712         struct nlattr *nest;
 713
 714         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 715         if (hdr == NULL)
 716                 return -1;
 717
 718         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
 719             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
 720                 goto nla_put_failure;
 721
 722         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 723         if (nla_grps == NULL)
 724                 goto nla_put_failure;
 725
 726         nest = nla_nest_start(skb, 1);
 727         if (nest == NULL)
 728                 goto nla_put_failure;
 729
 730         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 731             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 732                            grp->name))
 733                 goto nla_put_failure;
 734
 735         nla_nest_end(skb, nest);
 736         nla_nest_end(skb, nla_grps);
 737
 738         return genlmsg_end(skb, hdr);
 739
 740 nla_put_failure:
 741         genlmsg_cancel(skb, hdr);
 742         return -EMSGSIZE;
 743 }
 744
 745 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 746 {
 747
 748         int i, n = 0;
 749         struct genl_family *rt;
 750         struct net *net = sock_net(skb->sk);
 751         int chains_to_skip = cb->args[0];
 752         int fams_to_skip = cb->args[1];
 753
 754         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 755                 n = 0;
 756                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 757                         if (!rt->netnsok && !net_eq(net, &init_net))
 758                                 continue;
 759                         if (++n < fams_to_skip)
 760                                 continue;
 761                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 762                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 763                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 764                                 goto errout;
 765                 }
 766
 767                 fams_to_skip = 0;
 768         }
 769
 770 errout:
 771         cb->args[0] = i;
 772         cb->args[1] = n;
 773
 774         return skb->len;
 775 }
 776
 777 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 778                                              u32 portid, int seq, u8 cmd)
 779 {
 780         struct sk_buff *skb;
 781         int err;
 782
 783         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 784         if (skb == NULL)
 785                 return ERR_PTR(-ENOBUFS);
 786
 787         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 788         if (err < 0) {
 789                 nlmsg_free(skb);
 790                 return ERR_PTR(err);
 791         }
 792
 793         return skb;
 794 }
 795
 796 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 797                                             u32 portid, int seq, u8 cmd)
 798 {
 799         struct sk_buff *skb;
 800         int err;
 801
 802         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 803         if (skb == NULL)
 804                 return ERR_PTR(-ENOBUFS);
 805
 806         err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd);
 807         if (err < 0) {
 808                 nlmsg_free(skb);
 809                 return ERR_PTR(err);
 810         }
 811
 812         return skb;
 813 }
 814
 815 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 816         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 817         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 818                                     .len = GENL_NAMSIZ - 1 },
 819 };
 820
 821 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 822 {
 823         struct sk_buff *msg;
 824         struct genl_family *res = NULL;
 825         int err = -EINVAL;
 826
 827         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 828                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 829                 res = genl_family_find_byid(id);
 830                 err = -ENOENT;
 831         }
 832
 833         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 834                 char *name;
 835
 836                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 837                 res = genl_family_find_byname(name);
 838 #ifdef CONFIG_MODULES
 839                 if (res == NULL) {
 840                         genl_unlock();
 841                         up_read(&cb_lock);
 842                         request_module("net-pf-%d-proto-%d-family-%s",
 843                                        PF_NETLINK, NETLINK_GENERIC, name);
 844                         down_read(&cb_lock);
 845                         genl_lock();
 846                         res = genl_family_find_byname(name);
 847                 }
 848 #endif
 849                 err = -ENOENT;
 850         }
 851
 852         if (res == NULL)
 853                 return err;
 854
 855         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 856                 /* family doesn't exist here */
 857                 return -ENOENT;
 858         }
 859
 860         msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
 861                                     CTRL_CMD_NEWFAMILY);
 862         if (IS_ERR(msg))
 863                 return PTR_ERR(msg);
 864
 865         return genlmsg_reply(msg, info);
 866 }
 867
 868 static int genl_ctrl_event(int event, void *data)
 869 {
 870         struct sk_buff *msg;
 871         struct genl_family *family;
 872         struct genl_multicast_group *grp;
 873
 874         /* genl is still initialising */
 875         if (!init_net.genl_sock)
 876                 return 0;
 877
 878         switch (event) {
 879         case CTRL_CMD_NEWFAMILY:
 880         case CTRL_CMD_DELFAMILY:
 881                 family = data;
 882                 msg = ctrl_build_family_msg(family, 0, 0, event);
 883                 break;
 884         case CTRL_CMD_NEWMCAST_GRP:
 885         case CTRL_CMD_DELMCAST_GRP:
 886                 grp = data;
 887                 family = grp->family;
 888                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 889                 break;
 890         default:
 891                 return -EINVAL;
 892         }
 893
 894         if (IS_ERR(msg))
 895                 return PTR_ERR(msg);
 896
 897         if (!family->netnsok) {
 898                 genlmsg_multicast_netns(&init_net, msg, 0,
 899                                         GENL_ID_CTRL, GFP_KERNEL);
 900         } else {
 901                 rcu_read_lock();
 902                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
 903                 rcu_read_unlock();
 904         }
 905
 906         return 0;
 907 }
 908
 909 static struct genl_ops genl_ctrl_ops = {
 910         .cmd            = CTRL_CMD_GETFAMILY,
 911         .doit           = ctrl_getfamily,
 912         .dumpit         = ctrl_dumpfamily,
 913         .policy         = ctrl_policy,
 914 };
 915
 916 static struct genl_multicast_group notify_grp = {
 917         .name           = "notify",
 918 };
 919
 920 static int __net_init genl_pernet_init(struct net *net)
 921 {
 922         struct netlink_kernel_cfg cfg = {
 923                 .input          = genl_rcv,
 924                 .flags          = NL_CFG_F_NONROOT_RECV,
 925         };
 926
 927         /* we'll bump the group number right afterwards */
 928         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
 929
 930         if (!net->genl_sock && net_eq(net, &init_net))
 931                 panic("GENL: Cannot initialize generic netlink\n");
 932
 933         if (!net->genl_sock)
 934                 return -ENOMEM;
 935
 936         return 0;
 937 }
 938
 939 static void __net_exit genl_pernet_exit(struct net *net)
 940 {
 941         netlink_kernel_release(net->genl_sock);
 942         net->genl_sock = NULL;
 943 }
 944
 945 static struct pernet_operations genl_pernet_ops = {
 946         .init = genl_pernet_init,
 947         .exit = genl_pernet_exit,
 948 };
 949
 950 static int __init genl_init(void)
 951 {
 952         int i, err;
 953
 954         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 955                 INIT_LIST_HEAD(&family_ht[i]);
 956
 957         err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1);
 958         if (err < 0)
 959                 goto problem;
 960
 961         err = register_pernet_subsys(&genl_pernet_ops);
 962         if (err)
 963                 goto problem;
 964
 965         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 966         if (err < 0)
 967                 goto problem;
 968
 969         return 0;
 970
 971 problem:
 972         panic("GENL: Cannot register controller: %d\n", err);
 973 }
 974
 975 subsys_initcall(genl_init);
 976
 977 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
 978                          gfp_t flags)
 979 {
 980         struct sk_buff *tmp;
 981         struct net *net, *prev = NULL;
 982         int err;
 983
 984         for_each_net_rcu(net) {
 985                 if (prev) {
 986                         tmp = skb_clone(skb, flags);
 987                         if (!tmp) {
 988                                 err = -ENOMEM;
 989                                 goto error;
 990                         }
 991                         err = nlmsg_multicast(prev->genl_sock, tmp,
 992                                               portid, group, flags);
 993                         if (err)
 994                                 goto error;
 995                 }
 996
 997                 prev = net;
 998         }
 999
1000         return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1001  error:
1002         kfree_skb(skb);
1003         return err;
1004 }
1005
1006 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group,
1007                             gfp_t flags)
1008 {
1009         return genlmsg_mcast(skb, portid, group, flags);
1010 }
1011 EXPORT_SYMBOL(genlmsg_multicast_allns);
1012
1013 void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
1014                  struct nlmsghdr *nlh, gfp_t flags)
1015 {
1016         struct sock *sk = net->genl_sock;
1017         int report = 0;
1018
1019         if (nlh)
1020                 report = nlmsg_report(nlh);
1021
1022         nlmsg_notify(sk, skb, portid, group, report, flags);
1023 }
1024 EXPORT_SYMBOL(genl_notify);