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