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  * Bit 1 is marked as already used since the drop-monitor code
  69  * abuses the API and thinks it can statically use group 1.
  70  * That group will typically conflict with other groups that
  71  * any proper users use.
  72  * Bit 17 is marked as already used since the VFS quota code
  73  * also abused this API and relied on family == group ID, we
  74  * cater to that by giving it a static family and group ID.
  75  */
  76 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_VFS_DQUOT);
  77 static unsigned long *mc_groups = &mc_group_start;
  78 static unsigned long mc_groups_longs = 1;
  79
  80 static int genl_ctrl_event(int event, void *data);
  81
  82 static inline unsigned int genl_family_hash(unsigned int id)
  83 {
  84         return id & GENL_FAM_TAB_MASK;
  85 }
  86
  87 static inline struct list_head *genl_family_chain(unsigned int id)
  88 {
  89         return &family_ht[genl_family_hash(id)];
  90 }
  91
  92 static struct genl_family *genl_family_find_byid(unsigned int id)
  93 {
  94         struct genl_family *f;
  95
  96         list_for_each_entry(f, genl_family_chain(id), family_list)
  97                 if (f->id == id)
  98                         return f;
  99
 100         return NULL;
 101 }
 102
 103 static struct genl_family *genl_family_find_byname(char *name)
 104 {
 105         struct genl_family *f;
 106         int i;
 107
 108         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 109                 list_for_each_entry(f, genl_family_chain(i), family_list)
 110                         if (strcmp(f->name, name) == 0)
 111                                 return f;
 112
 113         return NULL;
 114 }
 115
 116 static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
 117 {
 118         int i;
 119
 120         for (i = 0; i < family->n_ops; i++)
 121                 if (family->ops[i].cmd == cmd)
 122                         return &family->ops[i];
 123
 124         return NULL;
 125 }
 126
 127 /* Of course we are going to have problems once we hit
 128  * 2^16 alive types, but that can only happen by year 2K
 129 */
 130 static u16 genl_generate_id(void)
 131 {
 132         static u16 id_gen_idx = GENL_MIN_ID;
 133         int i;
 134
 135         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
 136                 if (id_gen_idx != GENL_ID_VFS_DQUOT &&
 137                     !genl_family_find_byid(id_gen_idx))
 138                         return id_gen_idx;
 139                 if (++id_gen_idx > GENL_MAX_ID)
 140                         id_gen_idx = GENL_MIN_ID;
 141         }
 142
 143         return 0;
 144 }
 145
 146 static struct genl_multicast_group notify_grp;
 147
 148 /**
 149  * genl_register_mc_group - register a multicast group
 150  *
 151  * Registers the specified multicast group and notifies userspace
 152  * about the new group.
 153  *
 154  * Returns 0 on success or a negative error code.
 155  *
 156  * @family: The generic netlink family the group shall be registered for.
 157  * @grp: The group to register, must have a name.
 158  */
 159 int genl_register_mc_group(struct genl_family *family,
 160                            struct genl_multicast_group *grp)
 161 {
 162         int id;
 163         unsigned long *new_groups;
 164         int err = 0;
 165
 166         BUG_ON(grp->name[0] == '\0');
 167         BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);
 168
 169         genl_lock_all();
 170
 171         /* special-case our own group and hacks */
 172         if (grp == &notify_grp)
 173                 id = GENL_ID_CTRL;
 174         else if (strcmp(family->name, "NET_DM") == 0)
 175                 id = 1;
 176         else if (strcmp(family->name, "VFS_DQUOT") == 0)
 177                 id = GENL_ID_VFS_DQUOT;
 178         else
 179                 id = find_first_zero_bit(mc_groups,
 180                                          mc_groups_longs * BITS_PER_LONG);
 181
 182
 183         if (id >= mc_groups_longs * BITS_PER_LONG) {
 184                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
 185
 186                 if (mc_groups == &mc_group_start) {
 187                         new_groups = kzalloc(nlen, GFP_KERNEL);
 188                         if (!new_groups) {
 189                                 err = -ENOMEM;
 190                                 goto out;
 191                         }
 192                         mc_groups = new_groups;
 193                         *mc_groups = mc_group_start;
 194                 } else {
 195                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
 196                         if (!new_groups) {
 197                                 err = -ENOMEM;
 198                                 goto out;
 199                         }
 200                         mc_groups = new_groups;
 201                         mc_groups[mc_groups_longs] = 0;
 202                 }
 203                 mc_groups_longs++;
 204         }
 205
 206         if (family->netnsok) {
 207                 struct net *net;
 208
 209                 netlink_table_grab();
 210                 rcu_read_lock();
 211                 for_each_net_rcu(net) {
 212                         err = __netlink_change_ngroups(net->genl_sock,
 213                                         mc_groups_longs * BITS_PER_LONG);
 214                         if (err) {
 215                                 /*
 216                                  * No need to roll back, can only fail if
 217                                  * memory allocation fails and then the
 218                                  * number of _possible_ groups has been
 219                                  * increased on some sockets which is ok.
 220                                  */
 221                                 rcu_read_unlock();
 222                                 netlink_table_ungrab();
 223                                 goto out;
 224                         }
 225                 }
 226                 rcu_read_unlock();
 227                 netlink_table_ungrab();
 228         } else {
 229                 err = netlink_change_ngroups(init_net.genl_sock,
 230                                              mc_groups_longs * BITS_PER_LONG);
 231                 if (err)
 232                         goto out;
 233         }
 234
 235         grp->id = id;
 236         set_bit(id, mc_groups);
 237         list_add_tail(&grp->list, &family->mcast_groups);
 238         grp->family = family;
 239
 240         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
 241  out:
 242         genl_unlock_all();
 243         return err;
 244 }
 245 EXPORT_SYMBOL(genl_register_mc_group);
 246
 247 static void __genl_unregister_mc_group(struct genl_family *family,
 248                                        struct genl_multicast_group *grp)
 249 {
 250         struct net *net;
 251         BUG_ON(grp->family != family);
 252
 253         netlink_table_grab();
 254         rcu_read_lock();
 255         for_each_net_rcu(net)
 256                 __netlink_clear_multicast_users(net->genl_sock, grp->id);
 257         rcu_read_unlock();
 258         netlink_table_ungrab();
 259
 260         if (grp->id != 1)
 261                 clear_bit(grp->id, mc_groups);
 262         list_del(&grp->list);
 263         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 264         grp->id = 0;
 265         grp->family = NULL;
 266 }
 267
 268 static void genl_unregister_mc_groups(struct genl_family *family)
 269 {
 270         struct genl_multicast_group *grp, *tmp;
 271
 272         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 273                 __genl_unregister_mc_group(family, grp);
 274 }
 275
 276 static int genl_validate_ops(struct genl_family *family)
 277 {
 278         const struct genl_ops *ops = family->ops;
 279         unsigned int n_ops = family->n_ops;
 280         int i, j;
 281
 282         if (WARN_ON(n_ops && !ops))
 283                 return -EINVAL;
 284
 285         if (!n_ops)
 286                 return 0;
 287
 288         for (i = 0; i < n_ops; i++) {
 289                 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
 290                         return -EINVAL;
 291                 for (j = i + 1; j < n_ops; j++)
 292                         if (ops[i].cmd == ops[j].cmd)
 293                                 return -EINVAL;
 294         }
 295
 296         /* family is not registered yet, so no locking needed */
 297         family->ops = ops;
 298         family->n_ops = n_ops;
 299
 300         return 0;
 301 }
 302
 303 /**
 304  * __genl_register_family - register a generic netlink family
 305  * @family: generic netlink family
 306  *
 307  * Registers the specified family after validating it first. Only one
 308  * family may be registered with the same family name or identifier.
 309  * The family id may equal GENL_ID_GENERATE causing an unique id to
 310  * be automatically generated and assigned.
 311  *
 312  * The family's ops array must already be assigned, you can use the
 313  * genl_register_family_with_ops() helper function.
 314  *
 315  * Return 0 on success or a negative error code.
 316  */
 317 int __genl_register_family(struct genl_family *family)
 318 {
 319         int err = -EINVAL;
 320
 321         if (family->id && family->id < GENL_MIN_ID)
 322                 goto errout;
 323
 324         if (family->id > GENL_MAX_ID)
 325                 goto errout;
 326
 327         err = genl_validate_ops(family);
 328         if (err)
 329                 return err;
 330
 331         INIT_LIST_HEAD(&family->mcast_groups);
 332
 333         genl_lock_all();
 334
 335         if (genl_family_find_byname(family->name)) {
 336                 err = -EEXIST;
 337                 goto errout_locked;
 338         }
 339
 340         if (family->id == GENL_ID_GENERATE) {
 341                 u16 newid = genl_generate_id();
 342
 343                 if (!newid) {
 344                         err = -ENOMEM;
 345                         goto errout_locked;
 346                 }
 347
 348                 family->id = newid;
 349         } else if (genl_family_find_byid(family->id)) {
 350                 err = -EEXIST;
 351                 goto errout_locked;
 352         }
 353
 354         if (family->maxattr && !family->parallel_ops) {
 355                 family->attrbuf = kmalloc((family->maxattr+1) *
 356                                         sizeof(struct nlattr *), GFP_KERNEL);
 357                 if (family->attrbuf == NULL) {
 358                         err = -ENOMEM;
 359                         goto errout_locked;
 360                 }
 361         } else
 362                 family->attrbuf = NULL;
 363
 364         list_add_tail(&family->family_list, genl_family_chain(family->id));
 365         genl_unlock_all();
 366
 367         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 368
 369         return 0;
 370
 371 errout_locked:
 372         genl_unlock_all();
 373 errout:
 374         return err;
 375 }
 376 EXPORT_SYMBOL(__genl_register_family);
 377
 378 /**
 379  * genl_unregister_family - unregister generic netlink family
 380  * @family: generic netlink family
 381  *
 382  * Unregisters the specified family.
 383  *
 384  * Returns 0 on success or a negative error code.
 385  */
 386 int genl_unregister_family(struct genl_family *family)
 387 {
 388         struct genl_family *rc;
 389
 390         genl_lock_all();
 391
 392         genl_unregister_mc_groups(family);
 393
 394         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 395                 if (family->id != rc->id || strcmp(rc->name, family->name))
 396                         continue;
 397
 398                 list_del(&rc->family_list);
 399                 family->n_ops = 0;
 400                 genl_unlock_all();
 401
 402                 kfree(family->attrbuf);
 403                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 404                 return 0;
 405         }
 406
 407         genl_unlock_all();
 408
 409         return -ENOENT;
 410 }
 411 EXPORT_SYMBOL(genl_unregister_family);
 412
 413 /**
 414  * genlmsg_put - Add generic netlink header to netlink message
 415  * @skb: socket buffer holding the message
 416  * @portid: netlink portid the message is addressed to
 417  * @seq: sequence number (usually the one of the sender)
 418  * @family: generic netlink family
 419  * @flags: netlink message flags
 420  * @cmd: generic netlink command
 421  *
 422  * Returns pointer to user specific header
 423  */
 424 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 425                                 struct genl_family *family, int flags, u8 cmd)
 426 {
 427         struct nlmsghdr *nlh;
 428         struct genlmsghdr *hdr;
 429
 430         nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 431                         family->hdrsize, flags);
 432         if (nlh == NULL)
 433                 return NULL;
 434
 435         hdr = nlmsg_data(nlh);
 436         hdr->cmd = cmd;
 437         hdr->version = family->version;
 438         hdr->reserved = 0;
 439
 440         return (char *) hdr + GENL_HDRLEN;
 441 }
 442 EXPORT_SYMBOL(genlmsg_put);
 443
 444 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 445 {
 446         /* our ops are always const - netlink API doesn't propagate that */
 447         const struct genl_ops *ops = cb->data;
 448         int rc;
 449
 450         genl_lock();
 451         rc = ops->dumpit(skb, cb);
 452         genl_unlock();
 453         return rc;
 454 }
 455
 456 static int genl_lock_done(struct netlink_callback *cb)
 457 {
 458         /* our ops are always const - netlink API doesn't propagate that */
 459         const struct genl_ops *ops = cb->data;
 460         int rc = 0;
 461
 462         if (ops->done) {
 463                 genl_lock();
 464                 rc = ops->done(cb);
 465                 genl_unlock();
 466         }
 467         return rc;
 468 }
 469
 470 static int genl_family_rcv_msg(struct genl_family *family,
 471                                struct sk_buff *skb,
 472                                struct nlmsghdr *nlh)
 473 {
 474         const struct genl_ops *ops;
 475         struct net *net = sock_net(skb->sk);
 476         struct genl_info info;
 477         struct genlmsghdr *hdr = nlmsg_data(nlh);
 478         struct nlattr **attrbuf;
 479         int hdrlen, err;
 480
 481         /* this family doesn't exist in this netns */
 482         if (!family->netnsok && !net_eq(net, &init_net))
 483                 return -ENOENT;
 484
 485         hdrlen = GENL_HDRLEN + family->hdrsize;
 486         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 487                 return -EINVAL;
 488
 489         ops = genl_get_cmd(hdr->cmd, family);
 490         if (ops == NULL)
 491                 return -EOPNOTSUPP;
 492
 493         if ((ops->flags & GENL_ADMIN_PERM) &&
 494             !capable(CAP_NET_ADMIN))
 495                 return -EPERM;
 496
 497         if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
 498                 int rc;
 499
 500                 if (ops->dumpit == NULL)
 501                         return -EOPNOTSUPP;
 502
 503                 if (!family->parallel_ops) {
 504                         struct netlink_dump_control c = {
 505                                 .module = family->module,
 506                                 /* we have const, but the netlink API doesn't */
 507                                 .data = (void *)ops,
 508                                 .dump = genl_lock_dumpit,
 509                                 .done = genl_lock_done,
 510                         };
 511
 512                         genl_unlock();
 513                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 514                         genl_lock();
 515
 516                 } else {
 517                         struct netlink_dump_control c = {
 518                                 .module = family->module,
 519                                 .dump = ops->dumpit,
 520                                 .done = ops->done,
 521                         };
 522
 523                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 524                 }
 525
 526                 return rc;
 527         }
 528
 529         if (ops->doit == NULL)
 530                 return -EOPNOTSUPP;
 531
 532         if (family->maxattr && family->parallel_ops) {
 533                 attrbuf = kmalloc((family->maxattr+1) *
 534                                         sizeof(struct nlattr *), GFP_KERNEL);
 535                 if (attrbuf == NULL)
 536                         return -ENOMEM;
 537         } else
 538                 attrbuf = family->attrbuf;
 539
 540         if (attrbuf) {
 541                 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
 542                                   ops->policy);
 543                 if (err < 0)
 544                         goto out;
 545         }
 546
 547         info.snd_seq = nlh->nlmsg_seq;
 548         info.snd_portid = NETLINK_CB(skb).portid;
 549         info.nlhdr = nlh;
 550         info.genlhdr = nlmsg_data(nlh);
 551         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 552         info.attrs = attrbuf;
 553         genl_info_net_set(&info, net);
 554         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 555
 556         if (family->pre_doit) {
 557                 err = family->pre_doit(ops, skb, &info);
 558                 if (err)
 559                         goto out;
 560         }
 561
 562         err = ops->doit(skb, &info);
 563
 564         if (family->post_doit)
 565                 family->post_doit(ops, skb, &info);
 566
 567 out:
 568         if (family->parallel_ops)
 569                 kfree(attrbuf);
 570
 571         return err;
 572 }
 573
 574 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 575 {
 576         struct genl_family *family;
 577         int err;
 578
 579         family = genl_family_find_byid(nlh->nlmsg_type);
 580         if (family == NULL)
 581                 return -ENOENT;
 582
 583         if (!family->parallel_ops)
 584                 genl_lock();
 585
 586         err = genl_family_rcv_msg(family, skb, nlh);
 587
 588         if (!family->parallel_ops)
 589                 genl_unlock();
 590
 591         return err;
 592 }
 593
 594 static void genl_rcv(struct sk_buff *skb)
 595 {
 596         down_read(&cb_lock);
 597         netlink_rcv_skb(skb, &genl_rcv_msg);
 598         up_read(&cb_lock);
 599 }
 600
 601 /**************************************************************************
 602  * Controller
 603  **************************************************************************/
 604
 605 static struct genl_family genl_ctrl = {
 606         .id = GENL_ID_CTRL,
 607         .name = "nlctrl",
 608         .version = 0x2,
 609         .maxattr = CTRL_ATTR_MAX,
 610         .netnsok = true,
 611 };
 612
 613 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 614                           u32 flags, struct sk_buff *skb, u8 cmd)
 615 {
 616         void *hdr;
 617
 618         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 619         if (hdr == NULL)
 620                 return -1;
 621
 622         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 623             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 624             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 625             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 626             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 627                 goto nla_put_failure;
 628
 629         if (family->n_ops) {
 630                 struct nlattr *nla_ops;
 631                 int i;
 632
 633                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 634                 if (nla_ops == NULL)
 635                         goto nla_put_failure;
 636
 637                 for (i = 0; i < family->n_ops; i++) {
 638                         struct nlattr *nest;
 639                         const struct genl_ops *ops = &family->ops[i];
 640                         u32 op_flags = ops->flags;
 641
 642                         if (ops->dumpit)
 643                                 op_flags |= GENL_CMD_CAP_DUMP;
 644                         if (ops->doit)
 645                                 op_flags |= GENL_CMD_CAP_DO;
 646                         if (ops->policy)
 647                                 op_flags |= GENL_CMD_CAP_HASPOL;
 648
 649                         nest = nla_nest_start(skb, i + 1);
 650                         if (nest == NULL)
 651                                 goto nla_put_failure;
 652
 653                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
 654                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 655                                 goto nla_put_failure;
 656
 657                         nla_nest_end(skb, nest);
 658                 }
 659
 660                 nla_nest_end(skb, nla_ops);
 661         }
 662
 663         if (!list_empty(&family->mcast_groups)) {
 664                 struct genl_multicast_group *grp;
 665                 struct nlattr *nla_grps;
 666                 int idx = 1;
 667
 668                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 669                 if (nla_grps == NULL)
 670                         goto nla_put_failure;
 671
 672                 list_for_each_entry(grp, &family->mcast_groups, list) {
 673                         struct nlattr *nest;
 674
 675                         nest = nla_nest_start(skb, idx++);
 676                         if (nest == NULL)
 677                                 goto nla_put_failure;
 678
 679                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 680                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 681                                            grp->name))
 682                                 goto nla_put_failure;
 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 portid,
 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, portid, seq, &genl_ctrl, flags, cmd);
 705         if (hdr == NULL)
 706                 return -1;
 707
 708         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) ||
 709             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id))
 710                 goto nla_put_failure;
 711
 712         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 713         if (nla_grps == NULL)
 714                 goto nla_put_failure;
 715
 716         nest = nla_nest_start(skb, 1);
 717         if (nest == NULL)
 718                 goto nla_put_failure;
 719
 720         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 721             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 722                            grp->name))
 723                 goto nla_put_failure;
 724
 725         nla_nest_end(skb, nest);
 726         nla_nest_end(skb, nla_grps);
 727
 728         return genlmsg_end(skb, hdr);
 729
 730 nla_put_failure:
 731         genlmsg_cancel(skb, hdr);
 732         return -EMSGSIZE;
 733 }
 734
 735 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 736 {
 737
 738         int i, n = 0;
 739         struct genl_family *rt;
 740         struct net *net = sock_net(skb->sk);
 741         int chains_to_skip = cb->args[0];
 742         int fams_to_skip = cb->args[1];
 743
 744         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 745                 n = 0;
 746                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 747                         if (!rt->netnsok && !net_eq(net, &init_net))
 748                                 continue;
 749                         if (++n < fams_to_skip)
 750                                 continue;
 751                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 752                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 753                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 754                                 goto errout;
 755                 }
 756
 757                 fams_to_skip = 0;
 758         }
 759
 760 errout:
 761         cb->args[0] = i;
 762         cb->args[1] = n;
 763
 764         return skb->len;
 765 }
 766
 767 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 768                                              u32 portid, int seq, u8 cmd)
 769 {
 770         struct sk_buff *skb;
 771         int err;
 772
 773         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 774         if (skb == NULL)
 775                 return ERR_PTR(-ENOBUFS);
 776
 777         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 778         if (err < 0) {
 779                 nlmsg_free(skb);
 780                 return ERR_PTR(err);
 781         }
 782
 783         return skb;
 784 }
 785
 786 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 787                                             u32 portid, int seq, u8 cmd)
 788 {
 789         struct sk_buff *skb;
 790         int err;
 791
 792         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 793         if (skb == NULL)
 794                 return ERR_PTR(-ENOBUFS);
 795
 796         err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd);
 797         if (err < 0) {
 798                 nlmsg_free(skb);
 799                 return ERR_PTR(err);
 800         }
 801
 802         return skb;
 803 }
 804
 805 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 806         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 807         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 808                                     .len = GENL_NAMSIZ - 1 },
 809 };
 810
 811 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 812 {
 813         struct sk_buff *msg;
 814         struct genl_family *res = NULL;
 815         int err = -EINVAL;
 816
 817         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 818                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 819                 res = genl_family_find_byid(id);
 820                 err = -ENOENT;
 821         }
 822
 823         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 824                 char *name;
 825
 826                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 827                 res = genl_family_find_byname(name);
 828 #ifdef CONFIG_MODULES
 829                 if (res == NULL) {
 830                         genl_unlock();
 831                         up_read(&cb_lock);
 832                         request_module("net-pf-%d-proto-%d-family-%s",
 833                                        PF_NETLINK, NETLINK_GENERIC, name);
 834                         down_read(&cb_lock);
 835                         genl_lock();
 836                         res = genl_family_find_byname(name);
 837                 }
 838 #endif
 839                 err = -ENOENT;
 840         }
 841
 842         if (res == NULL)
 843                 return err;
 844
 845         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 846                 /* family doesn't exist here */
 847                 return -ENOENT;
 848         }
 849
 850         msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
 851                                     CTRL_CMD_NEWFAMILY);
 852         if (IS_ERR(msg))
 853                 return PTR_ERR(msg);
 854
 855         return genlmsg_reply(msg, info);
 856 }
 857
 858 static int genl_ctrl_event(int event, void *data)
 859 {
 860         struct sk_buff *msg;
 861         struct genl_family *family;
 862         struct genl_multicast_group *grp;
 863
 864         /* genl is still initialising */
 865         if (!init_net.genl_sock)
 866                 return 0;
 867
 868         switch (event) {
 869         case CTRL_CMD_NEWFAMILY:
 870         case CTRL_CMD_DELFAMILY:
 871                 family = data;
 872                 msg = ctrl_build_family_msg(family, 0, 0, event);
 873                 break;
 874         case CTRL_CMD_NEWMCAST_GRP:
 875         case CTRL_CMD_DELMCAST_GRP:
 876                 grp = data;
 877                 family = grp->family;
 878                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 879                 break;
 880         default:
 881                 return -EINVAL;
 882         }
 883
 884         if (IS_ERR(msg))
 885                 return PTR_ERR(msg);
 886
 887         if (!family->netnsok) {
 888                 genlmsg_multicast_netns(&init_net, msg, 0,
 889                                         GENL_ID_CTRL, GFP_KERNEL);
 890         } else {
 891                 rcu_read_lock();
 892                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
 893                 rcu_read_unlock();
 894         }
 895
 896         return 0;
 897 }
 898
 899 static struct genl_ops genl_ctrl_ops[] = {
 900         {
 901                 .cmd            = CTRL_CMD_GETFAMILY,
 902                 .doit           = ctrl_getfamily,
 903                 .dumpit         = ctrl_dumpfamily,
 904                 .policy         = ctrl_policy,
 905         },
 906 };
 907
 908 static struct genl_multicast_group notify_grp = {
 909         .name           = "notify",
 910 };
 911
 912 static int __net_init genl_pernet_init(struct net *net)
 913 {
 914         struct netlink_kernel_cfg cfg = {
 915                 .input          = genl_rcv,
 916                 .flags          = NL_CFG_F_NONROOT_RECV,
 917         };
 918
 919         /* we'll bump the group number right afterwards */
 920         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
 921
 922         if (!net->genl_sock && net_eq(net, &init_net))
 923                 panic("GENL: Cannot initialize generic netlink\n");
 924
 925         if (!net->genl_sock)
 926                 return -ENOMEM;
 927
 928         return 0;
 929 }
 930
 931 static void __net_exit genl_pernet_exit(struct net *net)
 932 {
 933         netlink_kernel_release(net->genl_sock);
 934         net->genl_sock = NULL;
 935 }
 936
 937 static struct pernet_operations genl_pernet_ops = {
 938         .init = genl_pernet_init,
 939         .exit = genl_pernet_exit,
 940 };
 941
 942 static int __init genl_init(void)
 943 {
 944         int i, err;
 945
 946         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 947                 INIT_LIST_HEAD(&family_ht[i]);
 948
 949         err = genl_register_family_with_ops(&genl_ctrl, genl_ctrl_ops);
 950         if (err < 0)
 951                 goto problem;
 952
 953         err = register_pernet_subsys(&genl_pernet_ops);
 954         if (err)
 955                 goto problem;
 956
 957         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 958         if (err < 0)
 959                 goto problem;
 960
 961         return 0;
 962
 963 problem:
 964         panic("GENL: Cannot register controller: %d\n", err);
 965 }
 966
 967 subsys_initcall(genl_init);
 968
 969 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
 970                          gfp_t flags)
 971 {
 972         struct sk_buff *tmp;
 973         struct net *net, *prev = NULL;
 974         int err;
 975
 976         for_each_net_rcu(net) {
 977                 if (prev) {
 978                         tmp = skb_clone(skb, flags);
 979                         if (!tmp) {
 980                                 err = -ENOMEM;
 981                                 goto error;
 982                         }
 983                         err = nlmsg_multicast(prev->genl_sock, tmp,
 984                                               portid, group, flags);
 985                         if (err)
 986                                 goto error;
 987                 }
 988
 989                 prev = net;
 990         }
 991
 992         return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
 993  error:
 994         kfree_skb(skb);
 995         return err;
 996 }
 997
 998 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group,
 999                             gfp_t flags)
1000 {
1001         return genlmsg_mcast(skb, portid, group, flags);
1002 }
1003 EXPORT_SYMBOL(genlmsg_multicast_allns);
1004
1005 void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
1006                  struct nlmsghdr *nlh, gfp_t flags)
1007 {
1008         struct sock *sk = net->genl_sock;
1009         int report = 0;
1010
1011         if (nlh)
1012                 report = nlmsg_report(nlh);
1013
1014         nlmsg_notify(sk, skb, portid, group, report, flags);
1015 }
1016 EXPORT_SYMBOL(genl_notify);