Pileus Git - ~andy/linux/blob - 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, struct genl_family *family,
  81                            struct genl_multicast_group *grp);
  82
  83 static inline unsigned int genl_family_hash(unsigned int id)
  84 {
  85         return id & GENL_FAM_TAB_MASK;
  86 }
  87
  88 static inline struct list_head *genl_family_chain(unsigned int id)
  89 {
  90         return &family_ht[genl_family_hash(id)];
  91 }
  92
  93 static struct genl_family *genl_family_find_byid(unsigned int id)
  94 {
  95         struct genl_family *f;
  96
  97         list_for_each_entry(f, genl_family_chain(id), family_list)
  98                 if (f->id == id)
  99                         return f;
 100
 101         return NULL;
 102 }
 103
 104 static struct genl_family *genl_family_find_byname(char *name)
 105 {
 106         struct genl_family *f;
 107         int i;
 108
 109         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 110                 list_for_each_entry(f, genl_family_chain(i), family_list)
 111                         if (strcmp(f->name, name) == 0)
 112                                 return f;
 113
 114         return NULL;
 115 }
 116
 117 static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
 118 {
 119         int i;
 120
 121         for (i = 0; i < family->n_ops; i++)
 122                 if (family->ops[i].cmd == cmd)
 123                         return &family->ops[i];
 124
 125         return NULL;
 126 }
 127
 128 /* Of course we are going to have problems once we hit
 129  * 2^16 alive types, but that can only happen by year 2K
 130 */
 131 static u16 genl_generate_id(void)
 132 {
 133         static u16 id_gen_idx = GENL_MIN_ID;
 134         int i;
 135
 136         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
 137                 if (id_gen_idx != GENL_ID_VFS_DQUOT &&
 138                     !genl_family_find_byid(id_gen_idx))
 139                         return id_gen_idx;
 140                 if (++id_gen_idx > GENL_MAX_ID)
 141                         id_gen_idx = GENL_MIN_ID;
 142         }
 143
 144         return 0;
 145 }
 146
 147 static struct genl_multicast_group notify_grp;
 148
 149 /**
 150  * genl_register_mc_group - register a multicast group
 151  *
 152  * Registers the specified multicast group and notifies userspace
 153  * about the new group.
 154  *
 155  * Returns 0 on success or a negative error code.
 156  *
 157  * @family: The generic netlink family the group shall be registered for.
 158  * @grp: The group to register, must have a name.
 159  */
 160 int genl_register_mc_group(struct genl_family *family,
 161                            struct genl_multicast_group *grp)
 162 {
 163         int id;
 164         unsigned long *new_groups;
 165         int err = 0;
 166
 167         BUG_ON(grp->name[0] == '\0');
 168         BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);
 169
 170         genl_lock_all();
 171
 172         /* special-case our own group and hacks */
 173         if (grp == &notify_grp)
 174                 id = GENL_ID_CTRL;
 175         else if (strcmp(family->name, "NET_DM") == 0)
 176                 id = 1;
 177         else if (strcmp(family->name, "VFS_DQUOT") == 0)
 178                 id = GENL_ID_VFS_DQUOT;
 179         else
 180                 id = find_first_zero_bit(mc_groups,
 181                                          mc_groups_longs * BITS_PER_LONG);
 182
 183
 184         if (id >= mc_groups_longs * BITS_PER_LONG) {
 185                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
 186
 187                 if (mc_groups == &mc_group_start) {
 188                         new_groups = kzalloc(nlen, GFP_KERNEL);
 189                         if (!new_groups) {
 190                                 err = -ENOMEM;
 191                                 goto out;
 192                         }
 193                         mc_groups = new_groups;
 194                         *mc_groups = mc_group_start;
 195                 } else {
 196                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
 197                         if (!new_groups) {
 198                                 err = -ENOMEM;
 199                                 goto out;
 200                         }
 201                         mc_groups = new_groups;
 202                         mc_groups[mc_groups_longs] = 0;
 203                 }
 204                 mc_groups_longs++;
 205         }
 206
 207         if (family->netnsok) {
 208                 struct net *net;
 209
 210                 netlink_table_grab();
 211                 rcu_read_lock();
 212                 for_each_net_rcu(net) {
 213                         err = __netlink_change_ngroups(net->genl_sock,
 214                                         mc_groups_longs * BITS_PER_LONG);
 215                         if (err) {
 216                                 /*
 217                                  * No need to roll back, can only fail if
 218                                  * memory allocation fails and then the
 219                                  * number of _possible_ groups has been
 220                                  * increased on some sockets which is ok.
 221                                  */
 222                                 rcu_read_unlock();
 223                                 netlink_table_ungrab();
 224                                 goto out;
 225                         }
 226                 }
 227                 rcu_read_unlock();
 228                 netlink_table_ungrab();
 229         } else {
 230                 err = netlink_change_ngroups(init_net.genl_sock,
 231                                              mc_groups_longs * BITS_PER_LONG);
 232                 if (err)
 233                         goto out;
 234         }
 235
 236         grp->id = id;
 237         set_bit(id, mc_groups);
 238         list_add_tail(&grp->list, &family->mcast_groups);
 239
 240         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, 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
 252         netlink_table_grab();
 253         rcu_read_lock();
 254         for_each_net_rcu(net)
 255                 __netlink_clear_multicast_users(net->genl_sock, grp->id);
 256         rcu_read_unlock();
 257         netlink_table_ungrab();
 258
 259         if (grp->id != 1)
 260                 clear_bit(grp->id, mc_groups);
 261         list_del(&grp->list);
 262         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, grp);
 263         grp->id = 0;
 264 }
 265
 266 static void genl_unregister_mc_groups(struct genl_family *family)
 267 {
 268         struct genl_multicast_group *grp, *tmp;
 269
 270         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 271                 __genl_unregister_mc_group(family, grp);
 272 }
 273
 274 static int genl_validate_ops(struct genl_family *family)
 275 {
 276         const struct genl_ops *ops = family->ops;
 277         unsigned int n_ops = family->n_ops;
 278         int i, j;
 279
 280         if (WARN_ON(n_ops && !ops))
 281                 return -EINVAL;
 282
 283         if (!n_ops)
 284                 return 0;
 285
 286         for (i = 0; i < n_ops; i++) {
 287                 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
 288                         return -EINVAL;
 289                 for (j = i + 1; j < n_ops; j++)
 290                         if (ops[i].cmd == ops[j].cmd)
 291                                 return -EINVAL;
 292         }
 293
 294         /* family is not registered yet, so no locking needed */
 295         family->ops = ops;
 296         family->n_ops = n_ops;
 297
 298         return 0;
 299 }
 300
 301 /**
 302  * __genl_register_family - register a generic netlink family
 303  * @family: generic netlink family
 304  *
 305  * Registers the specified family after validating it first. Only one
 306  * family may be registered with the same family name or identifier.
 307  * The family id may equal GENL_ID_GENERATE causing an unique id to
 308  * be automatically generated and assigned.
 309  *
 310  * The family's ops array must already be assigned, you can use the
 311  * genl_register_family_with_ops() helper function.
 312  *
 313  * Return 0 on success or a negative error code.
 314  */
 315 int __genl_register_family(struct genl_family *family)
 316 {
 317         int err = -EINVAL;
 318
 319         if (family->id && family->id < GENL_MIN_ID)
 320                 goto errout;
 321
 322         if (family->id > GENL_MAX_ID)
 323                 goto errout;
 324
 325         err = genl_validate_ops(family);
 326         if (err)
 327                 return err;
 328
 329         INIT_LIST_HEAD(&family->mcast_groups);
 330
 331         genl_lock_all();
 332
 333         if (genl_family_find_byname(family->name)) {
 334                 err = -EEXIST;
 335                 goto errout_locked;
 336         }
 337
 338         if (family->id == GENL_ID_GENERATE) {
 339                 u16 newid = genl_generate_id();
 340
 341                 if (!newid) {
 342                         err = -ENOMEM;
 343                         goto errout_locked;
 344                 }
 345
 346                 family->id = newid;
 347         } else if (genl_family_find_byid(family->id)) {
 348                 err = -EEXIST;
 349                 goto errout_locked;
 350         }
 351
 352         if (family->maxattr && !family->parallel_ops) {
 353                 family->attrbuf = kmalloc((family->maxattr+1) *
 354                                         sizeof(struct nlattr *), GFP_KERNEL);
 355                 if (family->attrbuf == NULL) {
 356                         err = -ENOMEM;
 357                         goto errout_locked;
 358                 }
 359         } else
 360                 family->attrbuf = NULL;
 361
 362         list_add_tail(&family->family_list, genl_family_chain(family->id));
 363         genl_unlock_all();
 364
 365         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL);
 366
 367         return 0;
 368
 369 errout_locked:
 370         genl_unlock_all();
 371 errout:
 372         return err;
 373 }
 374 EXPORT_SYMBOL(__genl_register_family);
 375
 376 /**
 377  * genl_unregister_family - unregister generic netlink family
 378  * @family: generic netlink family
 379  *
 380  * Unregisters the specified family.
 381  *
 382  * Returns 0 on success or a negative error code.
 383  */
 384 int genl_unregister_family(struct genl_family *family)
 385 {
 386         struct genl_family *rc;
 387
 388         genl_lock_all();
 389
 390         genl_unregister_mc_groups(family);
 391
 392         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 393                 if (family->id != rc->id || strcmp(rc->name, family->name))
 394                         continue;
 395
 396                 list_del(&rc->family_list);
 397                 family->n_ops = 0;
 398                 genl_unlock_all();
 399
 400                 kfree(family->attrbuf);
 401                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL);
 402                 return 0;
 403         }
 404
 405         genl_unlock_all();
 406
 407         return -ENOENT;
 408 }
 409 EXPORT_SYMBOL(genl_unregister_family);
 410
 411 /**
 412  * genlmsg_put - Add generic netlink header to netlink message
 413  * @skb: socket buffer holding the message
 414  * @portid: netlink portid the message is addressed to
 415  * @seq: sequence number (usually the one of the sender)
 416  * @family: generic netlink family
 417  * @flags: netlink message flags
 418  * @cmd: generic netlink command
 419  *
 420  * Returns pointer to user specific header
 421  */
 422 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 423                                 struct genl_family *family, int flags, u8 cmd)
 424 {
 425         struct nlmsghdr *nlh;
 426         struct genlmsghdr *hdr;
 427
 428         nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 429                         family->hdrsize, flags);
 430         if (nlh == NULL)
 431                 return NULL;
 432
 433         hdr = nlmsg_data(nlh);
 434         hdr->cmd = cmd;
 435         hdr->version = family->version;
 436         hdr->reserved = 0;
 437
 438         return (char *) hdr + GENL_HDRLEN;
 439 }
 440 EXPORT_SYMBOL(genlmsg_put);
 441
 442 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 443 {
 444         /* our ops are always const - netlink API doesn't propagate that */
 445         const struct genl_ops *ops = cb->data;
 446         int rc;
 447
 448         genl_lock();
 449         rc = ops->dumpit(skb, cb);
 450         genl_unlock();
 451         return rc;
 452 }
 453
 454 static int genl_lock_done(struct netlink_callback *cb)
 455 {
 456         /* our ops are always const - netlink API doesn't propagate that */
 457         const struct genl_ops *ops = cb->data;
 458         int rc = 0;
 459
 460         if (ops->done) {
 461                 genl_lock();
 462                 rc = ops->done(cb);
 463                 genl_unlock();
 464         }
 465         return rc;
 466 }
 467
 468 static int genl_family_rcv_msg(struct genl_family *family,
 469                                struct sk_buff *skb,
 470                                struct nlmsghdr *nlh)
 471 {
 472         const struct genl_ops *ops;
 473         struct net *net = sock_net(skb->sk);
 474         struct genl_info info;
 475         struct genlmsghdr *hdr = nlmsg_data(nlh);
 476         struct nlattr **attrbuf;
 477         int hdrlen, err;
 478
 479         /* this family doesn't exist in this netns */
 480         if (!family->netnsok && !net_eq(net, &init_net))
 481                 return -ENOENT;
 482
 483         hdrlen = GENL_HDRLEN + family->hdrsize;
 484         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 485                 return -EINVAL;
 486
 487         ops = genl_get_cmd(hdr->cmd, family);
 488         if (ops == NULL)
 489                 return -EOPNOTSUPP;
 490
 491         if ((ops->flags & GENL_ADMIN_PERM) &&
 492             !capable(CAP_NET_ADMIN))
 493                 return -EPERM;
 494
 495         if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
 496                 int rc;
 497
 498                 if (ops->dumpit == NULL)
 499                         return -EOPNOTSUPP;
 500
 501                 if (!family->parallel_ops) {
 502                         struct netlink_dump_control c = {
 503                                 .module = family->module,
 504                                 /* we have const, but the netlink API doesn't */
 505                                 .data = (void *)ops,
 506                                 .dump = genl_lock_dumpit,
 507                                 .done = genl_lock_done,
 508                         };
 509
 510                         genl_unlock();
 511                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 512                         genl_lock();
 513
 514                 } else {
 515                         struct netlink_dump_control c = {
 516                                 .module = family->module,
 517                                 .dump = ops->dumpit,
 518                                 .done = ops->done,
 519                         };
 520
 521                         rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 522                 }
 523
 524                 return rc;
 525         }
 526
 527         if (ops->doit == NULL)
 528                 return -EOPNOTSUPP;
 529
 530         if (family->maxattr && family->parallel_ops) {
 531                 attrbuf = kmalloc((family->maxattr+1) *
 532                                         sizeof(struct nlattr *), GFP_KERNEL);
 533                 if (attrbuf == NULL)
 534                         return -ENOMEM;
 535         } else
 536                 attrbuf = family->attrbuf;
 537
 538         if (attrbuf) {
 539                 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
 540                                   ops->policy);
 541                 if (err < 0)
 542                         goto out;
 543         }
 544
 545         info.snd_seq = nlh->nlmsg_seq;
 546         info.snd_portid = NETLINK_CB(skb).portid;
 547         info.nlhdr = nlh;
 548         info.genlhdr = nlmsg_data(nlh);
 549         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 550         info.attrs = attrbuf;
 551         genl_info_net_set(&info, net);
 552         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 553
 554         if (family->pre_doit) {
 555                 err = family->pre_doit(ops, skb, &info);
 556                 if (err)
 557                         goto out;
 558         }
 559
 560         err = ops->doit(skb, &info);
 561
 562         if (family->post_doit)
 563                 family->post_doit(ops, skb, &info);
 564
 565 out:
 566         if (family->parallel_ops)
 567                 kfree(attrbuf);
 568
 569         return err;
 570 }
 571
 572 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 573 {
 574         struct genl_family *family;
 575         int err;
 576
 577         family = genl_family_find_byid(nlh->nlmsg_type);
 578         if (family == NULL)
 579                 return -ENOENT;
 580
 581         if (!family->parallel_ops)
 582                 genl_lock();
 583
 584         err = genl_family_rcv_msg(family, skb, nlh);
 585
 586         if (!family->parallel_ops)
 587                 genl_unlock();
 588
 589         return err;
 590 }
 591
 592 static void genl_rcv(struct sk_buff *skb)
 593 {
 594         down_read(&cb_lock);
 595         netlink_rcv_skb(skb, &genl_rcv_msg);
 596         up_read(&cb_lock);
 597 }
 598
 599 /**************************************************************************
 600  * Controller
 601  **************************************************************************/
 602
 603 static struct genl_family genl_ctrl = {
 604         .id = GENL_ID_CTRL,
 605         .name = "nlctrl",
 606         .version = 0x2,
 607         .maxattr = CTRL_ATTR_MAX,
 608         .netnsok = true,
 609 };
 610
 611 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 612                           u32 flags, struct sk_buff *skb, u8 cmd)
 613 {
 614         void *hdr;
 615
 616         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 617         if (hdr == NULL)
 618                 return -1;
 619
 620         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 621             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 622             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 623             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 624             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 625                 goto nla_put_failure;
 626
 627         if (family->n_ops) {
 628                 struct nlattr *nla_ops;
 629                 int i;
 630
 631                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 632                 if (nla_ops == NULL)
 633                         goto nla_put_failure;
 634
 635                 for (i = 0; i < family->n_ops; i++) {
 636                         struct nlattr *nest;
 637                         const struct genl_ops *ops = &family->ops[i];
 638                         u32 op_flags = ops->flags;
 639
 640                         if (ops->dumpit)
 641                                 op_flags |= GENL_CMD_CAP_DUMP;
 642                         if (ops->doit)
 643                                 op_flags |= GENL_CMD_CAP_DO;
 644                         if (ops->policy)
 645                                 op_flags |= GENL_CMD_CAP_HASPOL;
 646
 647                         nest = nla_nest_start(skb, i + 1);
 648                         if (nest == NULL)
 649                                 goto nla_put_failure;
 650
 651                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
 652                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 653                                 goto nla_put_failure;
 654
 655                         nla_nest_end(skb, nest);
 656                 }
 657
 658                 nla_nest_end(skb, nla_ops);
 659         }
 660
 661         if (!list_empty(&family->mcast_groups)) {
 662                 struct genl_multicast_group *grp;
 663                 struct nlattr *nla_grps;
 664                 int idx = 1;
 665
 666                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 667                 if (nla_grps == NULL)
 668                         goto nla_put_failure;
 669
 670                 list_for_each_entry(grp, &family->mcast_groups, list) {
 671                         struct nlattr *nest;
 672
 673                         nest = nla_nest_start(skb, idx++);
 674                         if (nest == NULL)
 675                                 goto nla_put_failure;
 676
 677                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 678                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 679                                            grp->name))
 680                                 goto nla_put_failure;
 681
 682                         nla_nest_end(skb, nest);
 683                 }
 684                 nla_nest_end(skb, nla_grps);
 685         }
 686
 687         return genlmsg_end(skb, hdr);
 688
 689 nla_put_failure:
 690         genlmsg_cancel(skb, hdr);
 691         return -EMSGSIZE;
 692 }
 693
 694 static int ctrl_fill_mcgrp_info(struct genl_family *family,
 695                                 struct genl_multicast_group *grp, u32 portid,
 696                                 u32 seq, u32 flags, struct sk_buff *skb,
 697                                 u8 cmd)
 698 {
 699         void *hdr;
 700         struct nlattr *nla_grps;
 701         struct nlattr *nest;
 702
 703         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 704         if (hdr == NULL)
 705                 return -1;
 706
 707         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 708             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
 709                 goto nla_put_failure;
 710
 711         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 712         if (nla_grps == NULL)
 713                 goto nla_put_failure;
 714
 715         nest = nla_nest_start(skb, 1);
 716         if (nest == NULL)
 717                 goto nla_put_failure;
 718
 719         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
 720             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 721                            grp->name))
 722                 goto nla_put_failure;
 723
 724         nla_nest_end(skb, nest);
 725         nla_nest_end(skb, nla_grps);
 726
 727         return genlmsg_end(skb, hdr);
 728
 729 nla_put_failure:
 730         genlmsg_cancel(skb, hdr);
 731         return -EMSGSIZE;
 732 }
 733
 734 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 735 {
 736
 737         int i, n = 0;
 738         struct genl_family *rt;
 739         struct net *net = sock_net(skb->sk);
 740         int chains_to_skip = cb->args[0];
 741         int fams_to_skip = cb->args[1];
 742
 743         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 744                 n = 0;
 745                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 746                         if (!rt->netnsok && !net_eq(net, &init_net))
 747                                 continue;
 748                         if (++n < fams_to_skip)
 749                                 continue;
 750                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 751                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 752                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 753                                 goto errout;
 754                 }
 755
 756                 fams_to_skip = 0;
 757         }
 758
 759 errout:
 760         cb->args[0] = i;
 761         cb->args[1] = n;
 762
 763         return skb->len;
 764 }
 765
 766 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 767                                              u32 portid, int seq, u8 cmd)
 768 {
 769         struct sk_buff *skb;
 770         int err;
 771
 772         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 773         if (skb == NULL)
 774                 return ERR_PTR(-ENOBUFS);
 775
 776         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 777         if (err < 0) {
 778                 nlmsg_free(skb);
 779                 return ERR_PTR(err);
 780         }
 781
 782         return skb;
 783 }
 784
 785 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_family *family,
 786                                             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(family, 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, struct genl_family *family,
 859                            struct genl_multicast_group *grp)
 860 {
 861         struct sk_buff *msg;
 862
 863         /* genl is still initialising */
 864         if (!init_net.genl_sock)
 865                 return 0;
 866
 867         switch (event) {
 868         case CTRL_CMD_NEWFAMILY:
 869         case CTRL_CMD_DELFAMILY:
 870                 WARN_ON(grp);
 871                 msg = ctrl_build_family_msg(family, 0, 0, event);
 872                 break;
 873         case CTRL_CMD_NEWMCAST_GRP:
 874         case CTRL_CMD_DELMCAST_GRP:
 875                 BUG_ON(!grp);
 876                 msg = ctrl_build_mcgrp_msg(family, grp, 0, 0, event);
 877                 break;
 878         default:
 879                 return -EINVAL;
 880         }
 881
 882         if (IS_ERR(msg))
 883                 return PTR_ERR(msg);
 884
 885         if (!family->netnsok) {
 886                 genlmsg_multicast_netns(&init_net, msg, 0,
 887                                         GENL_ID_CTRL, GFP_KERNEL);
 888         } else {
 889                 rcu_read_lock();
 890                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
 891                 rcu_read_unlock();
 892         }
 893
 894         return 0;
 895 }
 896
 897 static struct genl_ops genl_ctrl_ops[] = {
 898         {
 899                 .cmd            = CTRL_CMD_GETFAMILY,
 900                 .doit           = ctrl_getfamily,
 901                 .dumpit         = ctrl_dumpfamily,
 902                 .policy         = ctrl_policy,
 903         },
 904 };
 905
 906 static struct genl_multicast_group notify_grp = {
 907         .name           = "notify",
 908 };
 909
 910 static int __net_init genl_pernet_init(struct net *net)
 911 {
 912         struct netlink_kernel_cfg cfg = {
 913                 .input          = genl_rcv,
 914                 .flags          = NL_CFG_F_NONROOT_RECV,
 915         };
 916
 917         /* we'll bump the group number right afterwards */
 918         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
 919
 920         if (!net->genl_sock && net_eq(net, &init_net))
 921                 panic("GENL: Cannot initialize generic netlink\n");
 922
 923         if (!net->genl_sock)
 924                 return -ENOMEM;
 925
 926         return 0;
 927 }
 928
 929 static void __net_exit genl_pernet_exit(struct net *net)
 930 {
 931         netlink_kernel_release(net->genl_sock);
 932         net->genl_sock = NULL;
 933 }
 934
 935 static struct pernet_operations genl_pernet_ops = {
 936         .init = genl_pernet_init,
 937         .exit = genl_pernet_exit,
 938 };
 939
 940 static int __init genl_init(void)
 941 {
 942         int i, err;
 943
 944         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 945                 INIT_LIST_HEAD(&family_ht[i]);
 946
 947         err = genl_register_family_with_ops(&genl_ctrl, genl_ctrl_ops);
 948         if (err < 0)
 949                 goto problem;
 950
 951         err = register_pernet_subsys(&genl_pernet_ops);
 952         if (err)
 953                 goto problem;
 954
 955         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 956         if (err < 0)
 957                 goto problem;
 958
 959         return 0;
 960
 961 problem:
 962         panic("GENL: Cannot register controller: %d\n", err);
 963 }
 964
 965 subsys_initcall(genl_init);
 966
 967 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
 968                          gfp_t flags)
 969 {
 970         struct sk_buff *tmp;
 971         struct net *net, *prev = NULL;
 972         int err;
 973
 974         for_each_net_rcu(net) {
 975                 if (prev) {
 976                         tmp = skb_clone(skb, flags);
 977                         if (!tmp) {
 978                                 err = -ENOMEM;
 979                                 goto error;
 980                         }
 981                         err = nlmsg_multicast(prev->genl_sock, tmp,
 982                                               portid, group, flags);
 983                         if (err)
 984                                 goto error;
 985                 }
 986
 987                 prev = net;
 988         }
 989
 990         return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
 991  error:
 992         kfree_skb(skb);
 993         return err;
 994 }
 995
 996 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group,
 997                             gfp_t flags)
 998 {
 999         return genlmsg_mcast(skb, portid, group, flags);
1000 }
1001 EXPORT_SYMBOL(genlmsg_multicast_allns);
1002
1003 void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group,
1004                  struct nlmsghdr *nlh, gfp_t flags)
1005 {
1006         struct sock *sk = net->genl_sock;
1007         int report = 0;
1008
1009         if (nlh)
1010                 report = nlmsg_report(nlh);
1011
1012         nlmsg_notify(sk, skb, portid, group, report, flags);
1013 }
1014 EXPORT_SYMBOL(genl_notify);