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 atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
  27 DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
  28
  29 void genl_lock(void)
  30 {
  31         mutex_lock(&genl_mutex);
  32 }
  33 EXPORT_SYMBOL(genl_lock);
  34
  35 void genl_unlock(void)
  36 {
  37         mutex_unlock(&genl_mutex);
  38 }
  39 EXPORT_SYMBOL(genl_unlock);
  40
  41 #ifdef CONFIG_LOCKDEP
  42 bool lockdep_genl_is_held(void)
  43 {
  44         return lockdep_is_held(&genl_mutex);
  45 }
  46 EXPORT_SYMBOL(lockdep_genl_is_held);
  47 #endif
  48
  49 static void genl_lock_all(void)
  50 {
  51         down_write(&cb_lock);
  52         genl_lock();
  53 }
  54
  55 static void genl_unlock_all(void)
  56 {
  57         genl_unlock();
  58         up_write(&cb_lock);
  59 }
  60
  61 #define GENL_FAM_TAB_SIZE       16
  62 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
  63
  64 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  65 /*
  66  * Bitmap of multicast groups that are currently in use.
  67  *
  68  * To avoid an allocation at boot of just one unsigned long,
  69  * declare it global instead.
  70  * Bit 0 is marked as already used since group 0 is invalid.
  71  * Bit 1 is marked as already used since the drop-monitor code
  72  * abuses the API and thinks it can statically use group 1.
  73  * That group will typically conflict with other groups that
  74  * any proper users use.
  75  * Bit 16 is marked as used since it's used for generic netlink
  76  * and the code no longer marks pre-reserved IDs as used.
  77  * Bit 17 is marked as already used since the VFS quota code
  78  * also abused this API and relied on family == group ID, we
  79  * cater to that by giving it a static family and group ID.
  80  * Bit 18 is marked as already used since the PMCRAID driver
  81  * did the same thing as the VFS quota code (maybe copied?)
  82  */
  83 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
  84                                       BIT(GENL_ID_VFS_DQUOT) |
  85                                       BIT(GENL_ID_PMCRAID);
  86 static unsigned long *mc_groups = &mc_group_start;
  87 static unsigned long mc_groups_longs = 1;
  88
  89 static int genl_ctrl_event(int event, struct genl_family *family,
  90                            const struct genl_multicast_group *grp,
  91                            int grp_id);
  92
  93 static inline unsigned int genl_family_hash(unsigned int id)
  94 {
  95         return id & GENL_FAM_TAB_MASK;
  96 }
  97
  98 static inline struct list_head *genl_family_chain(unsigned int id)
  99 {
 100         return &family_ht[genl_family_hash(id)];
 101 }
 102
 103 static struct genl_family *genl_family_find_byid(unsigned int id)
 104 {
 105         struct genl_family *f;
 106
 107         list_for_each_entry(f, genl_family_chain(id), family_list)
 108                 if (f->id == id)
 109                         return f;
 110
 111         return NULL;
 112 }
 113
 114 static struct genl_family *genl_family_find_byname(char *name)
 115 {
 116         struct genl_family *f;
 117         int i;
 118
 119         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 120                 list_for_each_entry(f, genl_family_chain(i), family_list)
 121                         if (strcmp(f->name, name) == 0)
 122                                 return f;
 123
 124         return NULL;
 125 }
 126
 127 static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
 128 {
 129         int i;
 130
 131         for (i = 0; i < family->n_ops; i++)
 132                 if (family->ops[i].cmd == cmd)
 133                         return &family->ops[i];
 134
 135         return NULL;
 136 }
 137
 138 /* Of course we are going to have problems once we hit
 139  * 2^16 alive types, but that can only happen by year 2K
 140 */
 141 static u16 genl_generate_id(void)
 142 {
 143         static u16 id_gen_idx = GENL_MIN_ID;
 144         int i;
 145
 146         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
 147                 if (id_gen_idx != GENL_ID_VFS_DQUOT &&
 148                     id_gen_idx != GENL_ID_PMCRAID &&
 149                     !genl_family_find_byid(id_gen_idx))
 150                         return id_gen_idx;
 151                 if (++id_gen_idx > GENL_MAX_ID)
 152                         id_gen_idx = GENL_MIN_ID;
 153         }
 154
 155         return 0;
 156 }
 157
 158 static int genl_allocate_reserve_groups(int n_groups, int *first_id)
 159 {
 160         unsigned long *new_groups;
 161         int start = 0;
 162         int i;
 163         int id;
 164         bool fits;
 165
 166         do {
 167                 if (start == 0)
 168                         id = find_first_zero_bit(mc_groups,
 169                                                  mc_groups_longs *
 170                                                  BITS_PER_LONG);
 171                 else
 172                         id = find_next_zero_bit(mc_groups,
 173                                                 mc_groups_longs * BITS_PER_LONG,
 174                                                 start);
 175
 176                 fits = true;
 177                 for (i = id;
 178                      i < min_t(int, id + n_groups,
 179                                mc_groups_longs * BITS_PER_LONG);
 180                      i++) {
 181                         if (test_bit(i, mc_groups)) {
 182                                 start = i;
 183                                 fits = false;
 184                                 break;
 185                         }
 186                 }
 187
 188                 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
 189                         unsigned long new_longs = mc_groups_longs +
 190                                                   BITS_TO_LONGS(n_groups);
 191                         size_t nlen = new_longs * sizeof(unsigned long);
 192
 193                         if (mc_groups == &mc_group_start) {
 194                                 new_groups = kzalloc(nlen, GFP_KERNEL);
 195                                 if (!new_groups)
 196                                         return -ENOMEM;
 197                                 mc_groups = new_groups;
 198                                 *mc_groups = mc_group_start;
 199                         } else {
 200                                 new_groups = krealloc(mc_groups, nlen,
 201                                                       GFP_KERNEL);
 202                                 if (!new_groups)
 203                                         return -ENOMEM;
 204                                 mc_groups = new_groups;
 205                                 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
 206                                         mc_groups[mc_groups_longs + i] = 0;
 207                         }
 208                         mc_groups_longs = new_longs;
 209                 }
 210         } while (!fits);
 211
 212         for (i = id; i < id + n_groups; i++)
 213                 set_bit(i, mc_groups);
 214         *first_id = id;
 215         return 0;
 216 }
 217
 218 static struct genl_family genl_ctrl;
 219
 220 static int genl_validate_assign_mc_groups(struct genl_family *family)
 221 {
 222         int first_id;
 223         int n_groups = family->n_mcgrps;
 224         int err = 0, i;
 225         bool groups_allocated = false;
 226
 227         if (!n_groups)
 228                 return 0;
 229
 230         for (i = 0; i < n_groups; i++) {
 231                 const struct genl_multicast_group *grp = &family->mcgrps[i];
 232
 233                 if (WARN_ON(grp->name[0] == '\0'))
 234                         return -EINVAL;
 235                 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
 236                         return -EINVAL;
 237         }
 238
 239         /* special-case our own group and hacks */
 240         if (family == &genl_ctrl) {
 241                 first_id = GENL_ID_CTRL;
 242                 BUG_ON(n_groups != 1);
 243         } else if (strcmp(family->name, "NET_DM") == 0) {
 244                 first_id = 1;
 245                 BUG_ON(n_groups != 1);
 246         } else if (family->id == GENL_ID_VFS_DQUOT) {
 247                 first_id = GENL_ID_VFS_DQUOT;
 248                 BUG_ON(n_groups != 1);
 249         } else if (family->id == GENL_ID_PMCRAID) {
 250                 first_id = GENL_ID_PMCRAID;
 251                 BUG_ON(n_groups != 1);
 252         } else {
 253                 groups_allocated = true;
 254                 err = genl_allocate_reserve_groups(n_groups, &first_id);
 255                 if (err)
 256                         return err;
 257         }
 258
 259         family->mcgrp_offset = first_id;
 260
 261         /* if still initializing, can't and don't need to to realloc bitmaps */
 262         if (!init_net.genl_sock)
 263                 return 0;
 264
 265         if (family->netnsok) {
 266                 struct net *net;
 267
 268                 netlink_table_grab();
 269                 rcu_read_lock();
 270                 for_each_net_rcu(net) {
 271                         err = __netlink_change_ngroups(net->genl_sock,
 272                                         mc_groups_longs * BITS_PER_LONG);
 273                         if (err) {
 274                                 /*
 275                                  * No need to roll back, can only fail if
 276                                  * memory allocation fails and then the
 277                                  * number of _possible_ groups has been
 278                                  * increased on some sockets which is ok.
 279                                  */
 280                                 break;
 281                         }
 282                 }
 283                 rcu_read_unlock();
 284                 netlink_table_ungrab();
 285         } else {
 286                 err = netlink_change_ngroups(init_net.genl_sock,
 287                                              mc_groups_longs * BITS_PER_LONG);
 288         }
 289
 290         if (groups_allocated && err) {
 291                 for (i = 0; i < family->n_mcgrps; i++)
 292                         clear_bit(family->mcgrp_offset + i, mc_groups);
 293         }
 294
 295         return err;
 296 }
 297
 298 static void genl_unregister_mc_groups(struct genl_family *family)
 299 {
 300         struct net *net;
 301         int i;
 302
 303         netlink_table_grab();
 304         rcu_read_lock();
 305         for_each_net_rcu(net) {
 306                 for (i = 0; i < family->n_mcgrps; i++)
 307                         __netlink_clear_multicast_users(
 308                                 net->genl_sock, family->mcgrp_offset + i);
 309         }
 310         rcu_read_unlock();
 311         netlink_table_ungrab();
 312
 313         for (i = 0; i < family->n_mcgrps; i++) {
 314                 int grp_id = family->mcgrp_offset + i;
 315
 316                 if (grp_id != 1)
 317                         clear_bit(grp_id, mc_groups);
 318                 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
 319                                 &family->mcgrps[i], grp_id);
 320         }
 321 }
 322
 323 static int genl_validate_ops(const struct genl_family *family)
 324 {
 325         const struct genl_ops *ops = family->ops;
 326         unsigned int n_ops = family->n_ops;
 327         int i, j;
 328
 329         if (WARN_ON(n_ops && !ops))
 330                 return -EINVAL;
 331
 332         if (!n_ops)
 333                 return 0;
 334
 335         for (i = 0; i < n_ops; i++) {
 336                 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
 337                         return -EINVAL;
 338                 for (j = i + 1; j < n_ops; j++)
 339                         if (ops[i].cmd == ops[j].cmd)
 340                                 return -EINVAL;
 341         }
 342
 343         return 0;
 344 }
 345
 346 /**
 347  * __genl_register_family - register a generic netlink family
 348  * @family: generic netlink family
 349  *
 350  * Registers the specified family after validating it first. Only one
 351  * family may be registered with the same family name or identifier.
 352  * The family id may equal GENL_ID_GENERATE causing an unique id to
 353  * be automatically generated and assigned.
 354  *
 355  * The family's ops array must already be assigned, you can use the
 356  * genl_register_family_with_ops() helper function.
 357  *
 358  * Return 0 on success or a negative error code.
 359  */
 360 int __genl_register_family(struct genl_family *family)
 361 {
 362         int err = -EINVAL, i;
 363
 364         if (family->id && family->id < GENL_MIN_ID)
 365                 goto errout;
 366
 367         if (family->id > GENL_MAX_ID)
 368                 goto errout;
 369
 370         err = genl_validate_ops(family);
 371         if (err)
 372                 return err;
 373
 374         genl_lock_all();
 375
 376         if (genl_family_find_byname(family->name)) {
 377                 err = -EEXIST;
 378                 goto errout_locked;
 379         }
 380
 381         if (family->id == GENL_ID_GENERATE) {
 382                 u16 newid = genl_generate_id();
 383
 384                 if (!newid) {
 385                         err = -ENOMEM;
 386                         goto errout_locked;
 387                 }
 388
 389                 family->id = newid;
 390         } else if (genl_family_find_byid(family->id)) {
 391                 err = -EEXIST;
 392                 goto errout_locked;
 393         }
 394
 395         if (family->maxattr && !family->parallel_ops) {
 396                 family->attrbuf = kmalloc((family->maxattr+1) *
 397                                         sizeof(struct nlattr *), GFP_KERNEL);
 398                 if (family->attrbuf == NULL) {
 399                         err = -ENOMEM;
 400                         goto errout_locked;
 401                 }
 402         } else
 403                 family->attrbuf = NULL;
 404
 405         err = genl_validate_assign_mc_groups(family);
 406         if (err)
 407                 goto errout_free;
 408
 409         list_add_tail(&family->family_list, genl_family_chain(family->id));
 410         genl_unlock_all();
 411
 412         /* send all events */
 413         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
 414         for (i = 0; i < family->n_mcgrps; i++)
 415                 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
 416                                 &family->mcgrps[i], family->mcgrp_offset + i);
 417
 418         return 0;
 419
 420 errout_free:
 421         kfree(family->attrbuf);
 422 errout_locked:
 423         genl_unlock_all();
 424 errout:
 425         return err;
 426 }
 427 EXPORT_SYMBOL(__genl_register_family);
 428
 429 /**
 430  * genl_unregister_family - unregister generic netlink family
 431  * @family: generic netlink family
 432  *
 433  * Unregisters the specified family.
 434  *
 435  * Returns 0 on success or a negative error code.
 436  */
 437 int genl_unregister_family(struct genl_family *family)
 438 {
 439         struct genl_family *rc;
 440
 441         genl_lock_all();
 442
 443         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 444                 if (family->id != rc->id || strcmp(rc->name, family->name))
 445                         continue;
 446
 447                 genl_unregister_mc_groups(family);
 448
 449                 list_del(&rc->family_list);
 450                 family->n_ops = 0;
 451                 up_write(&cb_lock);
 452                 wait_event(genl_sk_destructing_waitq,
 453                            atomic_read(&genl_sk_destructing_cnt) == 0);
 454                 genl_unlock();
 455
 456                 kfree(family->attrbuf);
 457                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
 458                 return 0;
 459         }
 460
 461         genl_unlock_all();
 462
 463         return -ENOENT;
 464 }
 465 EXPORT_SYMBOL(genl_unregister_family);
 466
 467 /**
 468  * genlmsg_put - Add generic netlink header to netlink message
 469  * @skb: socket buffer holding the message
 470  * @portid: netlink portid the message is addressed to
 471  * @seq: sequence number (usually the one of the sender)
 472  * @family: generic netlink family
 473  * @flags: netlink message flags
 474  * @cmd: generic netlink command
 475  *
 476  * Returns pointer to user specific header
 477  */
 478 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 479                                 struct genl_family *family, int flags, u8 cmd)
 480 {
 481         struct nlmsghdr *nlh;
 482         struct genlmsghdr *hdr;
 483
 484         nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 485                         family->hdrsize, flags);
 486         if (nlh == NULL)
 487                 return NULL;
 488
 489         hdr = nlmsg_data(nlh);
 490         hdr->cmd = cmd;
 491         hdr->version = family->version;
 492         hdr->reserved = 0;
 493
 494         return (char *) hdr + GENL_HDRLEN;
 495 }
 496 EXPORT_SYMBOL(genlmsg_put);
 497
 498 static int genl_lock_start(struct netlink_callback *cb)
 499 {
 500         /* our ops are always const - netlink API doesn't propagate that */
 501         const struct genl_ops *ops = cb->data;
 502         int rc = 0;
 503
 504         if (ops->start) {
 505                 genl_lock();
 506                 rc = ops->start(cb);
 507                 genl_unlock();
 508         }
 509         return rc;
 510 }
 511
 512 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 513 {
 514         /* our ops are always const - netlink API doesn't propagate that */
 515         const struct genl_ops *ops = cb->data;
 516         int rc;
 517
 518         genl_lock();
 519         rc = ops->dumpit(skb, cb);
 520         genl_unlock();
 521         return rc;
 522 }
 523
 524 static int genl_lock_done(struct netlink_callback *cb)
 525 {
 526         /* our ops are always const - netlink API doesn't propagate that */
 527         const struct genl_ops *ops = cb->data;
 528         int rc = 0;
 529
 530         if (ops->done) {
 531                 genl_lock();
 532                 rc = ops->done(cb);
 533                 genl_unlock();
 534         }
 535         return rc;
 536 }
 537
 538 static int genl_family_rcv_msg(struct genl_family *family,
 539                                struct sk_buff *skb,
 540                                struct nlmsghdr *nlh)
 541 {
 542         const struct genl_ops *ops;
 543         struct net *net = sock_net(skb->sk);
 544         struct genl_info info;
 545         struct genlmsghdr *hdr = nlmsg_data(nlh);
 546         struct nlattr **attrbuf;
 547         int hdrlen, err;
 548
 549         /* this family doesn't exist in this netns */
 550         if (!family->netnsok && !net_eq(net, &init_net))
 551                 return -ENOENT;
 552
 553         hdrlen = GENL_HDRLEN + family->hdrsize;
 554         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 555                 return -EINVAL;
 556
 557         ops = genl_get_cmd(hdr->cmd, family);
 558         if (ops == NULL)
 559                 return -EOPNOTSUPP;
 560
 561         if ((ops->flags & GENL_ADMIN_PERM) &&
 562             !netlink_capable(skb, CAP_NET_ADMIN))
 563                 return -EPERM;
 564
 565         if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
 566             !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 567                 return -EPERM;
 568
 569         if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
 570                 int rc;
 571
 572                 if (ops->dumpit == NULL)
 573                         return -EOPNOTSUPP;
 574
 575                 if (!family->parallel_ops) {
 576                         struct netlink_dump_control c = {
 577                                 .module = family->module,
 578                                 /* we have const, but the netlink API doesn't */
 579                                 .data = (void *)ops,
 580                                 .start = genl_lock_start,
 581                                 .dump = genl_lock_dumpit,
 582                                 .done = genl_lock_done,
 583                         };
 584
 585                         genl_unlock();
 586                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 587                         genl_lock();
 588
 589                 } else {
 590                         struct netlink_dump_control c = {
 591                                 .module = family->module,
 592                                 .start = ops->start,
 593                                 .dump = ops->dumpit,
 594                                 .done = ops->done,
 595                         };
 596
 597                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 598                 }
 599
 600                 return rc;
 601         }
 602
 603         if (ops->doit == NULL)
 604                 return -EOPNOTSUPP;
 605
 606         if (family->maxattr && family->parallel_ops) {
 607                 attrbuf = kmalloc((family->maxattr+1) *
 608                                         sizeof(struct nlattr *), GFP_KERNEL);
 609                 if (attrbuf == NULL)
 610                         return -ENOMEM;
 611         } else
 612                 attrbuf = family->attrbuf;
 613
 614         if (attrbuf) {
 615                 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
 616                                   ops->policy);
 617                 if (err < 0)
 618                         goto out;
 619         }
 620
 621         info.snd_seq = nlh->nlmsg_seq;
 622         info.snd_portid = NETLINK_CB(skb).portid;
 623         info.nlhdr = nlh;
 624         info.genlhdr = nlmsg_data(nlh);
 625         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 626         info.attrs = attrbuf;
 627         genl_info_net_set(&info, net);
 628         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 629
 630         if (family->pre_doit) {
 631                 err = family->pre_doit(ops, skb, &info);
 632                 if (err)
 633                         goto out;
 634         }
 635
 636         err = ops->doit(skb, &info);
 637
 638         if (family->post_doit)
 639                 family->post_doit(ops, skb, &info);
 640
 641 out:
 642         if (family->parallel_ops)
 643                 kfree(attrbuf);
 644
 645         return err;
 646 }
 647
 648 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 649 {
 650         struct genl_family *family;
 651         int err;
 652
 653         family = genl_family_find_byid(nlh->nlmsg_type);
 654         if (family == NULL)
 655                 return -ENOENT;
 656
 657         if (!family->parallel_ops)
 658                 genl_lock();
 659
 660         err = genl_family_rcv_msg(family, skb, nlh);
 661
 662         if (!family->parallel_ops)
 663                 genl_unlock();
 664
 665         return err;
 666 }
 667
 668 static void genl_rcv(struct sk_buff *skb)
 669 {
 670         down_read(&cb_lock);
 671         netlink_rcv_skb(skb, &genl_rcv_msg);
 672         up_read(&cb_lock);
 673 }
 674
 675 /**************************************************************************
 676  * Controller
 677  **************************************************************************/
 678
 679 static struct genl_family genl_ctrl = {
 680         .id = GENL_ID_CTRL,
 681         .name = "nlctrl",
 682         .version = 0x2,
 683         .maxattr = CTRL_ATTR_MAX,
 684         .netnsok = true,
 685 };
 686
 687 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 688                           u32 flags, struct sk_buff *skb, u8 cmd)
 689 {
 690         void *hdr;
 691
 692         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 693         if (hdr == NULL)
 694                 return -1;
 695
 696         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 697             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 698             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 699             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 700             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 701                 goto nla_put_failure;
 702
 703         if (family->n_ops) {
 704                 struct nlattr *nla_ops;
 705                 int i;
 706
 707                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 708                 if (nla_ops == NULL)
 709                         goto nla_put_failure;
 710
 711                 for (i = 0; i < family->n_ops; i++) {
 712                         struct nlattr *nest;
 713                         const struct genl_ops *ops = &family->ops[i];
 714                         u32 op_flags = ops->flags;
 715
 716                         if (ops->dumpit)
 717                                 op_flags |= GENL_CMD_CAP_DUMP;
 718                         if (ops->doit)
 719                                 op_flags |= GENL_CMD_CAP_DO;
 720                         if (ops->policy)
 721                                 op_flags |= GENL_CMD_CAP_HASPOL;
 722
 723                         nest = nla_nest_start(skb, i + 1);
 724                         if (nest == NULL)
 725                                 goto nla_put_failure;
 726
 727                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
 728                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 729                                 goto nla_put_failure;
 730
 731                         nla_nest_end(skb, nest);
 732                 }
 733
 734                 nla_nest_end(skb, nla_ops);
 735         }
 736
 737         if (family->n_mcgrps) {
 738                 struct nlattr *nla_grps;
 739                 int i;
 740
 741                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 742                 if (nla_grps == NULL)
 743                         goto nla_put_failure;
 744
 745                 for (i = 0; i < family->n_mcgrps; i++) {
 746                         struct nlattr *nest;
 747                         const struct genl_multicast_group *grp;
 748
 749                         grp = &family->mcgrps[i];
 750
 751                         nest = nla_nest_start(skb, i + 1);
 752                         if (nest == NULL)
 753                                 goto nla_put_failure;
 754
 755                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
 756                                         family->mcgrp_offset + i) ||
 757                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 758                                            grp->name))
 759                                 goto nla_put_failure;
 760
 761                         nla_nest_end(skb, nest);
 762                 }
 763                 nla_nest_end(skb, nla_grps);
 764         }
 765
 766         genlmsg_end(skb, hdr);
 767         return 0;
 768
 769 nla_put_failure:
 770         genlmsg_cancel(skb, hdr);
 771         return -EMSGSIZE;
 772 }
 773
 774 static int ctrl_fill_mcgrp_info(struct genl_family *family,
 775                                 const struct genl_multicast_group *grp,
 776                                 int grp_id, u32 portid, u32 seq, u32 flags,
 777                                 struct sk_buff *skb, u8 cmd)
 778 {
 779         void *hdr;
 780         struct nlattr *nla_grps;
 781         struct nlattr *nest;
 782
 783         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 784         if (hdr == NULL)
 785                 return -1;
 786
 787         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 788             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
 789                 goto nla_put_failure;
 790
 791         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 792         if (nla_grps == NULL)
 793                 goto nla_put_failure;
 794
 795         nest = nla_nest_start(skb, 1);
 796         if (nest == NULL)
 797                 goto nla_put_failure;
 798
 799         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
 800             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 801                            grp->name))
 802                 goto nla_put_failure;
 803
 804         nla_nest_end(skb, nest);
 805         nla_nest_end(skb, nla_grps);
 806
 807         genlmsg_end(skb, hdr);
 808         return 0;
 809
 810 nla_put_failure:
 811         genlmsg_cancel(skb, hdr);
 812         return -EMSGSIZE;
 813 }
 814
 815 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 816 {
 817
 818         int i, n = 0;
 819         struct genl_family *rt;
 820         struct net *net = sock_net(skb->sk);
 821         int chains_to_skip = cb->args[0];
 822         int fams_to_skip = cb->args[1];
 823
 824         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 825                 n = 0;
 826                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 827                         if (!rt->netnsok && !net_eq(net, &init_net))
 828                                 continue;
 829                         if (++n < fams_to_skip)
 830                                 continue;
 831                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 832                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 833                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 834                                 goto errout;
 835                 }
 836
 837                 fams_to_skip = 0;
 838         }
 839
 840 errout:
 841         cb->args[0] = i;
 842         cb->args[1] = n;
 843
 844         return skb->len;
 845 }
 846
 847 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 848                                              u32 portid, int seq, u8 cmd)
 849 {
 850         struct sk_buff *skb;
 851         int err;
 852
 853         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 854         if (skb == NULL)
 855                 return ERR_PTR(-ENOBUFS);
 856
 857         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 858         if (err < 0) {
 859                 nlmsg_free(skb);
 860                 return ERR_PTR(err);
 861         }
 862
 863         return skb;
 864 }
 865
 866 static struct sk_buff *
 867 ctrl_build_mcgrp_msg(struct genl_family *family,
 868                      const struct genl_multicast_group *grp,
 869                      int grp_id, u32 portid, int seq, u8 cmd)
 870 {
 871         struct sk_buff *skb;
 872         int err;
 873
 874         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 875         if (skb == NULL)
 876                 return ERR_PTR(-ENOBUFS);
 877
 878         err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
 879                                    seq, 0, skb, cmd);
 880         if (err < 0) {
 881                 nlmsg_free(skb);
 882                 return ERR_PTR(err);
 883         }
 884
 885         return skb;
 886 }
 887
 888 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 889         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 890         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 891                                     .len = GENL_NAMSIZ - 1 },
 892 };
 893
 894 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 895 {
 896         struct sk_buff *msg;
 897         struct genl_family *res = NULL;
 898         int err = -EINVAL;
 899
 900         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 901                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 902                 res = genl_family_find_byid(id);
 903                 err = -ENOENT;
 904         }
 905
 906         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 907                 char *name;
 908
 909                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 910                 res = genl_family_find_byname(name);
 911 #ifdef CONFIG_MODULES
 912                 if (res == NULL) {
 913                         genl_unlock();
 914                         up_read(&cb_lock);
 915                         request_module("net-pf-%d-proto-%d-family-%s",
 916                                        PF_NETLINK, NETLINK_GENERIC, name);
 917                         down_read(&cb_lock);
 918                         genl_lock();
 919                         res = genl_family_find_byname(name);
 920                 }
 921 #endif
 922                 err = -ENOENT;
 923         }
 924
 925         if (res == NULL)
 926                 return err;
 927
 928         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 929                 /* family doesn't exist here */
 930                 return -ENOENT;
 931         }
 932
 933         msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
 934                                     CTRL_CMD_NEWFAMILY);
 935         if (IS_ERR(msg))
 936                 return PTR_ERR(msg);
 937
 938         return genlmsg_reply(msg, info);
 939 }
 940
 941 static int genl_ctrl_event(int event, struct genl_family *family,
 942                            const struct genl_multicast_group *grp,
 943                            int grp_id)
 944 {
 945         struct sk_buff *msg;
 946
 947         /* genl is still initialising */
 948         if (!init_net.genl_sock)
 949                 return 0;
 950
 951         switch (event) {
 952         case CTRL_CMD_NEWFAMILY:
 953         case CTRL_CMD_DELFAMILY:
 954                 WARN_ON(grp);
 955                 msg = ctrl_build_family_msg(family, 0, 0, event);
 956                 break;
 957         case CTRL_CMD_NEWMCAST_GRP:
 958         case CTRL_CMD_DELMCAST_GRP:
 959                 BUG_ON(!grp);
 960                 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
 961                 break;
 962         default:
 963                 return -EINVAL;
 964         }
 965
 966         if (IS_ERR(msg))
 967                 return PTR_ERR(msg);
 968
 969         if (!family->netnsok) {
 970                 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
 971                                         0, GFP_KERNEL);
 972         } else {
 973                 rcu_read_lock();
 974                 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
 975                                         0, GFP_ATOMIC);
 976                 rcu_read_unlock();
 977         }
 978
 979         return 0;
 980 }
 981
 982 static const struct genl_ops genl_ctrl_ops[] = {
 983         {
 984                 .cmd            = CTRL_CMD_GETFAMILY,
 985                 .doit           = ctrl_getfamily,
 986                 .dumpit         = ctrl_dumpfamily,
 987                 .policy         = ctrl_policy,
 988         },
 989 };
 990
 991 static const struct genl_multicast_group genl_ctrl_groups[] = {
 992         { .name = "notify", },
 993 };
 994
 995 static int genl_bind(struct net *net, int group)
 996 {
 997         int i, err = -ENOENT;
 998
 999         down_read(&cb_lock);
1000         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
1001                 struct genl_family *f;
1002
1003                 list_for_each_entry(f, genl_family_chain(i), family_list) {
1004                         if (group >= f->mcgrp_offset &&
1005                             group < f->mcgrp_offset + f->n_mcgrps) {
1006                                 int fam_grp = group - f->mcgrp_offset;
1007
1008                                 if (!f->netnsok && net != &init_net)
1009                                         err = -ENOENT;
1010                                 else if (f->mcast_bind)
1011                                         err = f->mcast_bind(net, fam_grp);
1012                                 else
1013                                         err = 0;
1014                                 break;
1015                         }
1016                 }
1017         }
1018         up_read(&cb_lock);
1019
1020         return err;
1021 }
1022
1023 static void genl_unbind(struct net *net, int group)
1024 {
1025         int i;
1026
1027         down_read(&cb_lock);
1028         for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
1029                 struct genl_family *f;
1030
1031                 list_for_each_entry(f, genl_family_chain(i), family_list) {
1032                         if (group >= f->mcgrp_offset &&
1033                             group < f->mcgrp_offset + f->n_mcgrps) {
1034                                 int fam_grp = group - f->mcgrp_offset;
1035
1036                                 if (f->mcast_unbind)
1037                                         f->mcast_unbind(net, fam_grp);
1038                                 break;
1039                         }
1040                 }
1041         }
1042         up_read(&cb_lock);
1043 }
1044
1045 static int __net_init genl_pernet_init(struct net *net)
1046 {
1047         struct netlink_kernel_cfg cfg = {
1048                 .input          = genl_rcv,
1049                 .flags          = NL_CFG_F_NONROOT_RECV,
1050                 .bind           = genl_bind,
1051                 .unbind         = genl_unbind,
1052         };
1053
1054         /* we'll bump the group number right afterwards */
1055         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1056
1057         if (!net->genl_sock && net_eq(net, &init_net))
1058                 panic("GENL: Cannot initialize generic netlink\n");
1059
1060         if (!net->genl_sock)
1061                 return -ENOMEM;
1062
1063         return 0;
1064 }
1065
1066 static void __net_exit genl_pernet_exit(struct net *net)
1067 {
1068         netlink_kernel_release(net->genl_sock);
1069         net->genl_sock = NULL;
1070 }
1071
1072 static struct pernet_operations genl_pernet_ops = {
1073         .init = genl_pernet_init,
1074         .exit = genl_pernet_exit,
1075 };
1076
1077 static int __init genl_init(void)
1078 {
1079         int i, err;
1080
1081         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
1082                 INIT_LIST_HEAD(&family_ht[i]);
1083
1084         err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
1085                                                    genl_ctrl_groups);
1086         if (err < 0)
1087                 goto problem;
1088
1089         err = register_pernet_subsys(&genl_pernet_ops);
1090         if (err)
1091                 goto problem;
1092
1093         return 0;
1094
1095 problem:
1096         panic("GENL: Cannot register controller: %d\n", err);
1097 }
1098
1099 subsys_initcall(genl_init);
1100
1101 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1102                          gfp_t flags)
1103 {
1104         struct sk_buff *tmp;
1105         struct net *net, *prev = NULL;
1106         int err;
1107
1108         for_each_net_rcu(net) {
1109                 if (prev) {
1110                         tmp = skb_clone(skb, flags);
1111                         if (!tmp) {
1112                                 err = -ENOMEM;
1113                                 goto error;
1114                         }
1115                         err = nlmsg_multicast(prev->genl_sock, tmp,
1116                                               portid, group, flags);
1117                         if (err)
1118                                 goto error;
1119                 }
1120
1121                 prev = net;
1122         }
1123
1124         return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1125  error:
1126         kfree_skb(skb);
1127         return err;
1128 }
1129
1130 int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
1131                             u32 portid, unsigned int group, gfp_t flags)
1132 {
1133         if (WARN_ON_ONCE(group >= family->n_mcgrps))
1134                 return -EINVAL;
1135         group = family->mcgrp_offset + group;
1136         return genlmsg_mcast(skb, portid, group, flags);
1137 }
1138 EXPORT_SYMBOL(genlmsg_multicast_allns);
1139
1140 void genl_notify(struct genl_family *family, struct sk_buff *skb,
1141                  struct genl_info *info, u32 group, gfp_t flags)
1142 {
1143         struct net *net = genl_info_net(info);
1144         struct sock *sk = net->genl_sock;
1145         int report = 0;
1146
1147         if (info->nlhdr)
1148                 report = nlmsg_report(info->nlhdr);
1149
1150         if (WARN_ON_ONCE(group >= family->n_mcgrps))
1151                 return;
1152         group = family->mcgrp_offset + group;
1153         nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1154 }
1155 EXPORT_SYMBOL(genl_notify);