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 <net/sock.h>
  20 #include <net/genetlink.h>
  21
  22 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
  23
  24 static inline void genl_lock(void)
  25 {
  26         mutex_lock(&genl_mutex);
  27 }
  28
  29 static inline void genl_unlock(void)
  30 {
  31         mutex_unlock(&genl_mutex);
  32 }
  33
  34 #define GENL_FAM_TAB_SIZE       16
  35 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)
  36
  37 static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  38 /*
  39  * Bitmap of multicast groups that are currently in use.
  40  *
  41  * To avoid an allocation at boot of just one unsigned long,
  42  * declare it global instead.
  43  * Bit 0 is marked as already used since group 0 is invalid.
  44  */
  45 static unsigned long mc_group_start = 0x1;
  46 static unsigned long *mc_groups = &mc_group_start;
  47 static unsigned long mc_groups_longs = 1;
  48
  49 static int genl_ctrl_event(int event, void *data);
  50
  51 static inline unsigned int genl_family_hash(unsigned int id)
  52 {
  53         return id & GENL_FAM_TAB_MASK;
  54 }
  55
  56 static inline struct list_head *genl_family_chain(unsigned int id)
  57 {
  58         return &family_ht[genl_family_hash(id)];
  59 }
  60
  61 static struct genl_family *genl_family_find_byid(unsigned int id)
  62 {
  63         struct genl_family *f;
  64
  65         list_for_each_entry(f, genl_family_chain(id), family_list)
  66                 if (f->id == id)
  67                         return f;
  68
  69         return NULL;
  70 }
  71
  72 static struct genl_family *genl_family_find_byname(char *name)
  73 {
  74         struct genl_family *f;
  75         int i;
  76
  77         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
  78                 list_for_each_entry(f, genl_family_chain(i), family_list)
  79                         if (strcmp(f->name, name) == 0)
  80                                 return f;
  81
  82         return NULL;
  83 }
  84
  85 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
  86 {
  87         struct genl_ops *ops;
  88
  89         list_for_each_entry(ops, &family->ops_list, ops_list)
  90                 if (ops->cmd == cmd)
  91                         return ops;
  92
  93         return NULL;
  94 }
  95
  96 /* Of course we are going to have problems once we hit
  97  * 2^16 alive types, but that can only happen by year 2K
  98 */
  99 static inline u16 genl_generate_id(void)
 100 {
 101         static u16 id_gen_idx = GENL_MIN_ID;
 102         int i;
 103
 104         for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
 105                 if (!genl_family_find_byid(id_gen_idx))
 106                         return id_gen_idx;
 107                 if (++id_gen_idx > GENL_MAX_ID)
 108                         id_gen_idx = GENL_MIN_ID;
 109         }
 110
 111         return 0;
 112 }
 113
 114 static struct genl_multicast_group notify_grp;
 115
 116 /**
 117  * genl_register_mc_group - register a multicast group
 118  *
 119  * Registers the specified multicast group and notifies userspace
 120  * about the new group.
 121  *
 122  * Returns 0 on success or a negative error code.
 123  *
 124  * @family: The generic netlink family the group shall be registered for.
 125  * @grp: The group to register, must have a name.
 126  */
 127 int genl_register_mc_group(struct genl_family *family,
 128                            struct genl_multicast_group *grp)
 129 {
 130         int id;
 131         unsigned long *new_groups;
 132         int err = 0;
 133
 134         BUG_ON(grp->name[0] == '\0');
 135
 136         genl_lock();
 137
 138         /* special-case our own group */
 139         if (grp == &notify_grp)
 140                 id = GENL_ID_CTRL;
 141         else
 142                 id = find_first_zero_bit(mc_groups,
 143                                          mc_groups_longs * BITS_PER_LONG);
 144
 145
 146         if (id >= mc_groups_longs * BITS_PER_LONG) {
 147                 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
 148
 149                 if (mc_groups == &mc_group_start) {
 150                         new_groups = kzalloc(nlen, GFP_KERNEL);
 151                         if (!new_groups) {
 152                                 err = -ENOMEM;
 153                                 goto out;
 154                         }
 155                         mc_groups = new_groups;
 156                         *mc_groups = mc_group_start;
 157                 } else {
 158                         new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
 159                         if (!new_groups) {
 160                                 err = -ENOMEM;
 161                                 goto out;
 162                         }
 163                         mc_groups = new_groups;
 164                         mc_groups[mc_groups_longs] = 0;
 165                 }
 166                 mc_groups_longs++;
 167         }
 168
 169         if (family->netnsok) {
 170                 struct net *net;
 171
 172                 netlink_table_grab();
 173                 rcu_read_lock();
 174                 for_each_net_rcu(net) {
 175                         err = __netlink_change_ngroups(net->genl_sock,
 176                                         mc_groups_longs * BITS_PER_LONG);
 177                         if (err) {
 178                                 /*
 179                                  * No need to roll back, can only fail if
 180                                  * memory allocation fails and then the
 181                                  * number of _possible_ groups has been
 182                                  * increased on some sockets which is ok.
 183                                  */
 184                                 rcu_read_unlock();
 185                                 netlink_table_ungrab();
 186                                 goto out;
 187                         }
 188                 }
 189                 rcu_read_unlock();
 190                 netlink_table_ungrab();
 191         } else {
 192                 err = netlink_change_ngroups(init_net.genl_sock,
 193                                              mc_groups_longs * BITS_PER_LONG);
 194                 if (err)
 195                         goto out;
 196         }
 197
 198         grp->id = id;
 199         set_bit(id, mc_groups);
 200         list_add_tail(&grp->list, &family->mcast_groups);
 201         grp->family = family;
 202
 203         genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
 204  out:
 205         genl_unlock();
 206         return err;
 207 }
 208 EXPORT_SYMBOL(genl_register_mc_group);
 209
 210 static void __genl_unregister_mc_group(struct genl_family *family,
 211                                        struct genl_multicast_group *grp)
 212 {
 213         struct net *net;
 214         BUG_ON(grp->family != family);
 215
 216         netlink_table_grab();
 217         rcu_read_lock();
 218         for_each_net_rcu(net)
 219                 __netlink_clear_multicast_users(net->genl_sock, grp->id);
 220         rcu_read_unlock();
 221         netlink_table_ungrab();
 222
 223         clear_bit(grp->id, mc_groups);
 224         list_del(&grp->list);
 225         genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
 226         grp->id = 0;
 227         grp->family = NULL;
 228 }
 229
 230 /**
 231  * genl_unregister_mc_group - unregister a multicast group
 232  *
 233  * Unregisters the specified multicast group and notifies userspace
 234  * about it. All current listeners on the group are removed.
 235  *
 236  * Note: It is not necessary to unregister all multicast groups before
 237  *       unregistering the family, unregistering the family will cause
 238  *       all assigned multicast groups to be unregistered automatically.
 239  *
 240  * @family: Generic netlink family the group belongs to.
 241  * @grp: The group to unregister, must have been registered successfully
 242  *       previously.
 243  */
 244 void genl_unregister_mc_group(struct genl_family *family,
 245                               struct genl_multicast_group *grp)
 246 {
 247         genl_lock();
 248         __genl_unregister_mc_group(family, grp);
 249         genl_unlock();
 250 }
 251 EXPORT_SYMBOL(genl_unregister_mc_group);
 252
 253 static void genl_unregister_mc_groups(struct genl_family *family)
 254 {
 255         struct genl_multicast_group *grp, *tmp;
 256
 257         list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
 258                 __genl_unregister_mc_group(family, grp);
 259 }
 260
 261 /**
 262  * genl_register_ops - register generic netlink operations
 263  * @family: generic netlink family
 264  * @ops: operations to be registered
 265  *
 266  * Registers the specified operations and assigns them to the specified
 267  * family. Either a doit or dumpit callback must be specified or the
 268  * operation will fail. Only one operation structure per command
 269  * identifier may be registered.
 270  *
 271  * See include/net/genetlink.h for more documenation on the operations
 272  * structure.
 273  *
 274  * Returns 0 on success or a negative error code.
 275  */
 276 int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
 277 {
 278         int err = -EINVAL;
 279
 280         if (ops->dumpit == NULL && ops->doit == NULL)
 281                 goto errout;
 282
 283         if (genl_get_cmd(ops->cmd, family)) {
 284                 err = -EEXIST;
 285                 goto errout;
 286         }
 287
 288         if (ops->dumpit)
 289                 ops->flags |= GENL_CMD_CAP_DUMP;
 290         if (ops->doit)
 291                 ops->flags |= GENL_CMD_CAP_DO;
 292         if (ops->policy)
 293                 ops->flags |= GENL_CMD_CAP_HASPOL;
 294
 295         genl_lock();
 296         list_add_tail(&ops->ops_list, &family->ops_list);
 297         genl_unlock();
 298
 299         genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
 300         err = 0;
 301 errout:
 302         return err;
 303 }
 304
 305 /**
 306  * genl_unregister_ops - unregister generic netlink operations
 307  * @family: generic netlink family
 308  * @ops: operations to be unregistered
 309  *
 310  * Unregisters the specified operations and unassigns them from the
 311  * specified family. The operation blocks until the current message
 312  * processing has finished and doesn't start again until the
 313  * unregister process has finished.
 314  *
 315  * Note: It is not necessary to unregister all operations before
 316  *       unregistering the family, unregistering the family will cause
 317  *       all assigned operations to be unregistered automatically.
 318  *
 319  * Returns 0 on success or a negative error code.
 320  */
 321 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 322 {
 323         struct genl_ops *rc;
 324
 325         genl_lock();
 326         list_for_each_entry(rc, &family->ops_list, ops_list) {
 327                 if (rc == ops) {
 328                         list_del(&ops->ops_list);
 329                         genl_unlock();
 330                         genl_ctrl_event(CTRL_CMD_DELOPS, ops);
 331                         return 0;
 332                 }
 333         }
 334         genl_unlock();
 335
 336         return -ENOENT;
 337 }
 338
 339 /**
 340  * genl_register_family - register a generic netlink family
 341  * @family: generic netlink family
 342  *
 343  * Registers the specified family after validating it first. Only one
 344  * family may be registered with the same family name or identifier.
 345  * The family id may equal GENL_ID_GENERATE causing an unique id to
 346  * be automatically generated and assigned.
 347  *
 348  * Return 0 on success or a negative error code.
 349  */
 350 int genl_register_family(struct genl_family *family)
 351 {
 352         int err = -EINVAL;
 353
 354         if (family->id && family->id < GENL_MIN_ID)
 355                 goto errout;
 356
 357         if (family->id > GENL_MAX_ID)
 358                 goto errout;
 359
 360         INIT_LIST_HEAD(&family->ops_list);
 361         INIT_LIST_HEAD(&family->mcast_groups);
 362
 363         genl_lock();
 364
 365         if (genl_family_find_byname(family->name)) {
 366                 err = -EEXIST;
 367                 goto errout_locked;
 368         }
 369
 370         if (family->id == GENL_ID_GENERATE) {
 371                 u16 newid = genl_generate_id();
 372
 373                 if (!newid) {
 374                         err = -ENOMEM;
 375                         goto errout_locked;
 376                 }
 377
 378                 family->id = newid;
 379         } else if (genl_family_find_byid(family->id)) {
 380                 err = -EEXIST;
 381                 goto errout_locked;
 382         }
 383
 384         if (family->maxattr) {
 385                 family->attrbuf = kmalloc((family->maxattr+1) *
 386                                         sizeof(struct nlattr *), GFP_KERNEL);
 387                 if (family->attrbuf == NULL) {
 388                         err = -ENOMEM;
 389                         goto errout_locked;
 390                 }
 391         } else
 392                 family->attrbuf = NULL;
 393
 394         list_add_tail(&family->family_list, genl_family_chain(family->id));
 395         genl_unlock();
 396
 397         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
 398
 399         return 0;
 400
 401 errout_locked:
 402         genl_unlock();
 403 errout:
 404         return err;
 405 }
 406
 407 /**
 408  * genl_register_family_with_ops - register a generic netlink family
 409  * @family: generic netlink family
 410  * @ops: operations to be registered
 411  * @n_ops: number of elements to register
 412  *
 413  * Registers the specified family and operations from the specified table.
 414  * Only one family may be registered with the same family name or identifier.
 415  *
 416  * The family id may equal GENL_ID_GENERATE causing an unique id to
 417  * be automatically generated and assigned.
 418  *
 419  * Either a doit or dumpit callback must be specified for every registered
 420  * operation or the function will fail. Only one operation structure per
 421  * command identifier may be registered.
 422  *
 423  * See include/net/genetlink.h for more documenation on the operations
 424  * structure.
 425  *
 426  * This is equivalent to calling genl_register_family() followed by
 427  * genl_register_ops() for every operation entry in the table taking
 428  * care to unregister the family on error path.
 429  *
 430  * Return 0 on success or a negative error code.
 431  */
 432 int genl_register_family_with_ops(struct genl_family *family,
 433         struct genl_ops *ops, size_t n_ops)
 434 {
 435         int err, i;
 436
 437         err = genl_register_family(family);
 438         if (err)
 439                 return err;
 440
 441         for (i = 0; i < n_ops; ++i, ++ops) {
 442                 err = genl_register_ops(family, ops);
 443                 if (err)
 444                         goto err_out;
 445         }
 446         return 0;
 447 err_out:
 448         genl_unregister_family(family);
 449         return err;
 450 }
 451 EXPORT_SYMBOL(genl_register_family_with_ops);
 452
 453 /**
 454  * genl_unregister_family - unregister generic netlink family
 455  * @family: generic netlink family
 456  *
 457  * Unregisters the specified family.
 458  *
 459  * Returns 0 on success or a negative error code.
 460  */
 461 int genl_unregister_family(struct genl_family *family)
 462 {
 463         struct genl_family *rc;
 464
 465         genl_lock();
 466
 467         genl_unregister_mc_groups(family);
 468
 469         list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
 470                 if (family->id != rc->id || strcmp(rc->name, family->name))
 471                         continue;
 472
 473                 list_del(&rc->family_list);
 474                 INIT_LIST_HEAD(&family->ops_list);
 475                 genl_unlock();
 476
 477                 kfree(family->attrbuf);
 478                 genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
 479                 return 0;
 480         }
 481
 482         genl_unlock();
 483
 484         return -ENOENT;
 485 }
 486
 487 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 488 {
 489         struct genl_ops *ops;
 490         struct genl_family *family;
 491         struct net *net = sock_net(skb->sk);
 492         struct genl_info info;
 493         struct genlmsghdr *hdr = nlmsg_data(nlh);
 494         int hdrlen, err;
 495
 496         family = genl_family_find_byid(nlh->nlmsg_type);
 497         if (family == NULL)
 498                 return -ENOENT;
 499
 500         /* this family doesn't exist in this netns */
 501         if (!family->netnsok && !net_eq(net, &init_net))
 502                 return -ENOENT;
 503
 504         hdrlen = GENL_HDRLEN + family->hdrsize;
 505         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 506                 return -EINVAL;
 507
 508         ops = genl_get_cmd(hdr->cmd, family);
 509         if (ops == NULL)
 510                 return -EOPNOTSUPP;
 511
 512         if ((ops->flags & GENL_ADMIN_PERM) &&
 513             security_netlink_recv(skb, CAP_NET_ADMIN))
 514                 return -EPERM;
 515
 516         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 517                 if (ops->dumpit == NULL)
 518                         return -EOPNOTSUPP;
 519
 520                 genl_unlock();
 521                 err = netlink_dump_start(net->genl_sock, skb, nlh,
 522                                          ops->dumpit, ops->done);
 523                 genl_lock();
 524                 return err;
 525         }
 526
 527         if (ops->doit == NULL)
 528                 return -EOPNOTSUPP;
 529
 530         if (family->attrbuf) {
 531                 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 532                                   ops->policy);
 533                 if (err < 0)
 534                         return err;
 535         }
 536
 537         info.snd_seq = nlh->nlmsg_seq;
 538         info.snd_pid = NETLINK_CB(skb).pid;
 539         info.nlhdr = nlh;
 540         info.genlhdr = nlmsg_data(nlh);
 541         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 542         info.attrs = family->attrbuf;
 543         genl_info_net_set(&info, net);
 544
 545         return ops->doit(skb, &info);
 546 }
 547
 548 static void genl_rcv(struct sk_buff *skb)
 549 {
 550         genl_lock();
 551         netlink_rcv_skb(skb, &genl_rcv_msg);
 552         genl_unlock();
 553 }
 554
 555 /**************************************************************************
 556  * Controller
 557  **************************************************************************/
 558
 559 static struct genl_family genl_ctrl = {
 560         .id = GENL_ID_CTRL,
 561         .name = "nlctrl",
 562         .version = 0x2,
 563         .maxattr = CTRL_ATTR_MAX,
 564         .netnsok = true,
 565 };
 566
 567 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 568                           u32 flags, struct sk_buff *skb, u8 cmd)
 569 {
 570         void *hdr;
 571
 572         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 573         if (hdr == NULL)
 574                 return -1;
 575
 576         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
 577         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
 578         NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
 579         NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
 580         NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
 581
 582         if (!list_empty(&family->ops_list)) {
 583                 struct nlattr *nla_ops;
 584                 struct genl_ops *ops;
 585                 int idx = 1;
 586
 587                 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 588                 if (nla_ops == NULL)
 589                         goto nla_put_failure;
 590
 591                 list_for_each_entry(ops, &family->ops_list, ops_list) {
 592                         struct nlattr *nest;
 593
 594                         nest = nla_nest_start(skb, idx++);
 595                         if (nest == NULL)
 596                                 goto nla_put_failure;
 597
 598                         NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
 599                         NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
 600
 601                         nla_nest_end(skb, nest);
 602                 }
 603
 604                 nla_nest_end(skb, nla_ops);
 605         }
 606
 607         if (!list_empty(&family->mcast_groups)) {
 608                 struct genl_multicast_group *grp;
 609                 struct nlattr *nla_grps;
 610                 int idx = 1;
 611
 612                 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 613                 if (nla_grps == NULL)
 614                         goto nla_put_failure;
 615
 616                 list_for_each_entry(grp, &family->mcast_groups, list) {
 617                         struct nlattr *nest;
 618
 619                         nest = nla_nest_start(skb, idx++);
 620                         if (nest == NULL)
 621                                 goto nla_put_failure;
 622
 623                         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 624                         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 625                                        grp->name);
 626
 627                         nla_nest_end(skb, nest);
 628                 }
 629                 nla_nest_end(skb, nla_grps);
 630         }
 631
 632         return genlmsg_end(skb, hdr);
 633
 634 nla_put_failure:
 635         genlmsg_cancel(skb, hdr);
 636         return -EMSGSIZE;
 637 }
 638
 639 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
 640                                 u32 seq, u32 flags, struct sk_buff *skb,
 641                                 u8 cmd)
 642 {
 643         void *hdr;
 644         struct nlattr *nla_grps;
 645         struct nlattr *nest;
 646
 647         hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 648         if (hdr == NULL)
 649                 return -1;
 650
 651         NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
 652         NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
 653
 654         nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 655         if (nla_grps == NULL)
 656                 goto nla_put_failure;
 657
 658         nest = nla_nest_start(skb, 1);
 659         if (nest == NULL)
 660                 goto nla_put_failure;
 661
 662         NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
 663         NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
 664                        grp->name);
 665
 666         nla_nest_end(skb, nest);
 667         nla_nest_end(skb, nla_grps);
 668
 669         return genlmsg_end(skb, hdr);
 670
 671 nla_put_failure:
 672         genlmsg_cancel(skb, hdr);
 673         return -EMSGSIZE;
 674 }
 675
 676 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 677 {
 678
 679         int i, n = 0;
 680         struct genl_family *rt;
 681         struct net *net = sock_net(skb->sk);
 682         int chains_to_skip = cb->args[0];
 683         int fams_to_skip = cb->args[1];
 684
 685         for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 686                 n = 0;
 687                 list_for_each_entry(rt, genl_family_chain(i), family_list) {
 688                         if (!rt->netnsok && !net_eq(net, &init_net))
 689                                 continue;
 690                         if (++n < fams_to_skip)
 691                                 continue;
 692                         if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
 693                                            cb->nlh->nlmsg_seq, NLM_F_MULTI,
 694                                            skb, CTRL_CMD_NEWFAMILY) < 0)
 695                                 goto errout;
 696                 }
 697
 698                 fams_to_skip = 0;
 699         }
 700
 701 errout:
 702         cb->args[0] = i;
 703         cb->args[1] = n;
 704
 705         return skb->len;
 706 }
 707
 708 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 709                                              u32 pid, int seq, u8 cmd)
 710 {
 711         struct sk_buff *skb;
 712         int err;
 713
 714         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 715         if (skb == NULL)
 716                 return ERR_PTR(-ENOBUFS);
 717
 718         err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
 719         if (err < 0) {
 720                 nlmsg_free(skb);
 721                 return ERR_PTR(err);
 722         }
 723
 724         return skb;
 725 }
 726
 727 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
 728                                             u32 pid, int seq, u8 cmd)
 729 {
 730         struct sk_buff *skb;
 731         int err;
 732
 733         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 734         if (skb == NULL)
 735                 return ERR_PTR(-ENOBUFS);
 736
 737         err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
 738         if (err < 0) {
 739                 nlmsg_free(skb);
 740                 return ERR_PTR(err);
 741         }
 742
 743         return skb;
 744 }
 745
 746 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 747         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
 748         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
 749                                     .len = GENL_NAMSIZ - 1 },
 750 };
 751
 752 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 753 {
 754         struct sk_buff *msg;
 755         struct genl_family *res = NULL;
 756         int err = -EINVAL;
 757
 758         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 759                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 760                 res = genl_family_find_byid(id);
 761                 err = -ENOENT;
 762         }
 763
 764         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 765                 char *name;
 766
 767                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 768                 res = genl_family_find_byname(name);
 769                 err = -ENOENT;
 770         }
 771
 772         if (res == NULL)
 773                 return err;
 774
 775         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 776                 /* family doesn't exist here */
 777                 return -ENOENT;
 778         }
 779
 780         msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
 781                                     CTRL_CMD_NEWFAMILY);
 782         if (IS_ERR(msg))
 783                 return PTR_ERR(msg);
 784
 785         return genlmsg_reply(msg, info);
 786 }
 787
 788 static int genl_ctrl_event(int event, void *data)
 789 {
 790         struct sk_buff *msg;
 791         struct genl_family *family;
 792         struct genl_multicast_group *grp;
 793
 794         /* genl is still initialising */
 795         if (!init_net.genl_sock)
 796                 return 0;
 797
 798         switch (event) {
 799         case CTRL_CMD_NEWFAMILY:
 800         case CTRL_CMD_DELFAMILY:
 801                 family = data;
 802                 msg = ctrl_build_family_msg(family, 0, 0, event);
 803                 break;
 804         case CTRL_CMD_NEWMCAST_GRP:
 805         case CTRL_CMD_DELMCAST_GRP:
 806                 grp = data;
 807                 family = grp->family;
 808                 msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
 809                 break;
 810         default:
 811                 return -EINVAL;
 812         }
 813
 814         if (IS_ERR(msg))
 815                 return PTR_ERR(msg);
 816
 817         if (!family->netnsok) {
 818                 genlmsg_multicast_netns(&init_net, msg, 0,
 819                                         GENL_ID_CTRL, GFP_KERNEL);
 820         } else {
 821                 rcu_read_lock();
 822                 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC);
 823                 rcu_read_unlock();
 824         }
 825
 826         return 0;
 827 }
 828
 829 static struct genl_ops genl_ctrl_ops = {
 830         .cmd            = CTRL_CMD_GETFAMILY,
 831         .doit           = ctrl_getfamily,
 832         .dumpit         = ctrl_dumpfamily,
 833         .policy         = ctrl_policy,
 834 };
 835
 836 static struct genl_multicast_group notify_grp = {
 837         .name           = "notify",
 838 };
 839
 840 static int __net_init genl_pernet_init(struct net *net)
 841 {
 842         /* we'll bump the group number right afterwards */
 843         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
 844                                                genl_rcv, &genl_mutex,
 845                                                THIS_MODULE);
 846
 847         if (!net->genl_sock && net_eq(net, &init_net))
 848                 panic("GENL: Cannot initialize generic netlink\n");
 849
 850         if (!net->genl_sock)
 851                 return -ENOMEM;
 852
 853         return 0;
 854 }
 855
 856 static void __net_exit genl_pernet_exit(struct net *net)
 857 {
 858         netlink_kernel_release(net->genl_sock);
 859         net->genl_sock = NULL;
 860 }
 861
 862 static struct pernet_operations genl_pernet_ops = {
 863         .init = genl_pernet_init,
 864         .exit = genl_pernet_exit,
 865 };
 866
 867 static int __init genl_init(void)
 868 {
 869         int i, err;
 870
 871         for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 872                 INIT_LIST_HEAD(&family_ht[i]);
 873
 874         err = genl_register_family(&genl_ctrl);
 875         if (err < 0)
 876                 goto problem;
 877
 878         err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
 879         if (err < 0)
 880                 goto problem;
 881
 882         netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
 883
 884         err = register_pernet_subsys(&genl_pernet_ops);
 885         if (err)
 886                 goto problem;
 887
 888         err = genl_register_mc_group(&genl_ctrl, &notify_grp);
 889         if (err < 0)
 890                 goto problem;
 891
 892         return 0;
 893
 894 problem:
 895         panic("GENL: Cannot register controller: %d\n", err);
 896 }
 897
 898 subsys_initcall(genl_init);
 899
 900 EXPORT_SYMBOL(genl_register_ops);
 901 EXPORT_SYMBOL(genl_unregister_ops);
 902 EXPORT_SYMBOL(genl_register_family);
 903 EXPORT_SYMBOL(genl_unregister_family);
 904
 905 static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
 906                          gfp_t flags)
 907 {
 908         struct sk_buff *tmp;
 909         struct net *net, *prev = NULL;
 910         int err;
 911
 912         for_each_net_rcu(net) {
 913                 if (prev) {
 914                         tmp = skb_clone(skb, flags);
 915                         if (!tmp) {
 916                                 err = -ENOMEM;
 917                                 goto error;
 918                         }
 919                         err = nlmsg_multicast(prev->genl_sock, tmp,
 920                                               pid, group, flags);
 921                         if (err)
 922                                 goto error;
 923                 }
 924
 925                 prev = net;
 926         }
 927
 928         return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags);
 929  error:
 930         kfree_skb(skb);
 931         return err;
 932 }
 933
 934 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group,
 935                             gfp_t flags)
 936 {
 937         return genlmsg_mcast(skb, pid, group, flags);
 938 }
 939 EXPORT_SYMBOL(genlmsg_multicast_allns);