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/errno.h> 12 #include <linux/types.h> 13 #include <linux/socket.h> 14 #include <linux/string.h> 15 #include <linux/skbuff.h> 16 #include <linux/mutex.h> 17 #include <linux/bitmap.h> 18 #include <net/sock.h> 19 #include <net/genetlink.h> 20 21 struct sock *genl_sock = NULL; 22 23 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ 24 25 static inline void genl_lock(void) 26 { 27 mutex_lock(&genl_mutex); 28 } 29 30 static inline void genl_unlock(void) 31 { 32 mutex_unlock(&genl_mutex); 33 } 34 35 #define GENL_FAM_TAB_SIZE 16 36 #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) 37 38 static struct list_head family_ht[GENL_FAM_TAB_SIZE]; 39 /* 40 * Bitmap of multicast groups that are currently in use. 41 * 42 * To avoid an allocation at boot of just one unsigned long, 43 * declare it global instead. 44 * Bit 0 is marked as already used since group 0 is invalid. 45 */ 46 static unsigned long mc_group_start = 0x1; 47 static unsigned long *mc_groups = &mc_group_start; 48 static unsigned long mc_groups_longs = 1; 49 50 static int genl_ctrl_event(int event, void *data); 51 52 static inline unsigned int genl_family_hash(unsigned int id) 53 { 54 return id & GENL_FAM_TAB_MASK; 55 } 56 57 static inline struct list_head *genl_family_chain(unsigned int id) 58 { 59 return &family_ht[genl_family_hash(id)]; 60 } 61 62 static struct genl_family *genl_family_find_byid(unsigned int id) 63 { 64 struct genl_family *f; 65 66 list_for_each_entry(f, genl_family_chain(id), family_list) 67 if (f->id == id) 68 return f; 69 70 return NULL; 71 } 72 73 static struct genl_family *genl_family_find_byname(char *name) 74 { 75 struct genl_family *f; 76 int i; 77 78 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 79 list_for_each_entry(f, genl_family_chain(i), family_list) 80 if (strcmp(f->name, name) == 0) 81 return f; 82 83 return NULL; 84 } 85 86 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) 87 { 88 struct genl_ops *ops; 89 90 list_for_each_entry(ops, &family->ops_list, ops_list) 91 if (ops->cmd == cmd) 92 return ops; 93 94 return NULL; 95 } 96 97 /* Of course we are going to have problems once we hit 98 * 2^16 alive types, but that can only happen by year 2K 99 */ 100 static inline u16 genl_generate_id(void) 101 { 102 static u16 id_gen_idx; 103 int overflowed = 0; 104 105 do { 106 if (id_gen_idx == 0) 107 id_gen_idx = GENL_MIN_ID; 108 109 if (++id_gen_idx > GENL_MAX_ID) { 110 if (!overflowed) { 111 overflowed = 1; 112 id_gen_idx = 0; 113 continue; 114 } else 115 return 0; 116 } 117 118 } while (genl_family_find_byid(id_gen_idx)); 119 120 return id_gen_idx; 121 } 122 123 static struct genl_multicast_group notify_grp; 124 125 /** 126 * genl_register_mc_group - register a multicast group 127 * 128 * Registers the specified multicast group and notifies userspace 129 * about the new group. 130 * 131 * Returns 0 on success or a negative error code. 132 * 133 * @family: The generic netlink family the group shall be registered for. 134 * @grp: The group to register, must have a name. 135 */ 136 int genl_register_mc_group(struct genl_family *family, 137 struct genl_multicast_group *grp) 138 { 139 int id; 140 unsigned long *new_groups; 141 int err; 142 143 BUG_ON(grp->name[0] == '\0'); 144 145 genl_lock(); 146 147 /* special-case our own group */ 148 if (grp == ¬ify_grp) 149 id = GENL_ID_CTRL; 150 else 151 id = find_first_zero_bit(mc_groups, 152 mc_groups_longs * BITS_PER_LONG); 153 154 155 if (id >= mc_groups_longs * BITS_PER_LONG) { 156 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long); 157 158 if (mc_groups == &mc_group_start) { 159 new_groups = kzalloc(nlen, GFP_KERNEL); 160 if (!new_groups) { 161 err = -ENOMEM; 162 goto out; 163 } 164 mc_groups = new_groups; 165 *mc_groups = mc_group_start; 166 } else { 167 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL); 168 if (!new_groups) { 169 err = -ENOMEM; 170 goto out; 171 } 172 mc_groups = new_groups; 173 mc_groups[mc_groups_longs] = 0; 174 } 175 mc_groups_longs++; 176 } 177 178 err = netlink_change_ngroups(genl_sock, 179 mc_groups_longs * BITS_PER_LONG); 180 if (err) 181 goto out; 182 183 grp->id = id; 184 set_bit(id, mc_groups); 185 list_add_tail(&grp->list, &family->mcast_groups); 186 grp->family = family; 187 188 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp); 189 out: 190 genl_unlock(); 191 return err; 192 } 193 EXPORT_SYMBOL(genl_register_mc_group); 194 195 static void __genl_unregister_mc_group(struct genl_family *family, 196 struct genl_multicast_group *grp) 197 { 198 BUG_ON(grp->family != family); 199 netlink_clear_multicast_users(genl_sock, grp->id); 200 clear_bit(grp->id, mc_groups); 201 list_del(&grp->list); 202 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp); 203 grp->id = 0; 204 grp->family = NULL; 205 } 206 207 /** 208 * genl_unregister_mc_group - unregister a multicast group 209 * 210 * Unregisters the specified multicast group and notifies userspace 211 * about it. All current listeners on the group are removed. 212 * 213 * Note: It is not necessary to unregister all multicast groups before 214 * unregistering the family, unregistering the family will cause 215 * all assigned multicast groups to be unregistered automatically. 216 * 217 * @family: Generic netlink family the group belongs to. 218 * @grp: The group to unregister, must have been registered successfully 219 * previously. 220 */ 221 void genl_unregister_mc_group(struct genl_family *family, 222 struct genl_multicast_group *grp) 223 { 224 genl_lock(); 225 __genl_unregister_mc_group(family, grp); 226 genl_unlock(); 227 } 228 EXPORT_SYMBOL(genl_unregister_mc_group); 229 230 static void genl_unregister_mc_groups(struct genl_family *family) 231 { 232 struct genl_multicast_group *grp, *tmp; 233 234 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list) 235 __genl_unregister_mc_group(family, grp); 236 } 237 238 /** 239 * genl_register_ops - register generic netlink operations 240 * @family: generic netlink family 241 * @ops: operations to be registered 242 * 243 * Registers the specified operations and assigns them to the specified 244 * family. Either a doit or dumpit callback must be specified or the 245 * operation will fail. Only one operation structure per command 246 * identifier may be registered. 247 * 248 * See include/net/genetlink.h for more documenation on the operations 249 * structure. 250 * 251 * Returns 0 on success or a negative error code. 252 */ 253 int genl_register_ops(struct genl_family *family, struct genl_ops *ops) 254 { 255 int err = -EINVAL; 256 257 if (ops->dumpit == NULL && ops->doit == NULL) 258 goto errout; 259 260 if (genl_get_cmd(ops->cmd, family)) { 261 err = -EEXIST; 262 goto errout; 263 } 264 265 if (ops->dumpit) 266 ops->flags |= GENL_CMD_CAP_DUMP; 267 if (ops->doit) 268 ops->flags |= GENL_CMD_CAP_DO; 269 if (ops->policy) 270 ops->flags |= GENL_CMD_CAP_HASPOL; 271 272 genl_lock(); 273 list_add_tail(&ops->ops_list, &family->ops_list); 274 genl_unlock(); 275 276 genl_ctrl_event(CTRL_CMD_NEWOPS, ops); 277 err = 0; 278 errout: 279 return err; 280 } 281 282 /** 283 * genl_unregister_ops - unregister generic netlink operations 284 * @family: generic netlink family 285 * @ops: operations to be unregistered 286 * 287 * Unregisters the specified operations and unassigns them from the 288 * specified family. The operation blocks until the current message 289 * processing has finished and doesn't start again until the 290 * unregister process has finished. 291 * 292 * Note: It is not necessary to unregister all operations before 293 * unregistering the family, unregistering the family will cause 294 * all assigned operations to be unregistered automatically. 295 * 296 * Returns 0 on success or a negative error code. 297 */ 298 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops) 299 { 300 struct genl_ops *rc; 301 302 genl_lock(); 303 list_for_each_entry(rc, &family->ops_list, ops_list) { 304 if (rc == ops) { 305 list_del(&ops->ops_list); 306 genl_unlock(); 307 genl_ctrl_event(CTRL_CMD_DELOPS, ops); 308 return 0; 309 } 310 } 311 genl_unlock(); 312 313 return -ENOENT; 314 } 315 316 /** 317 * genl_register_family - register a generic netlink family 318 * @family: generic netlink family 319 * 320 * Registers the specified family after validating it first. Only one 321 * family may be registered with the same family name or identifier. 322 * The family id may equal GENL_ID_GENERATE causing an unique id to 323 * be automatically generated and assigned. 324 * 325 * Return 0 on success or a negative error code. 326 */ 327 int genl_register_family(struct genl_family *family) 328 { 329 int err = -EINVAL; 330 331 if (family->id && family->id < GENL_MIN_ID) 332 goto errout; 333 334 if (family->id > GENL_MAX_ID) 335 goto errout; 336 337 INIT_LIST_HEAD(&family->ops_list); 338 INIT_LIST_HEAD(&family->mcast_groups); 339 340 genl_lock(); 341 342 if (genl_family_find_byname(family->name)) { 343 err = -EEXIST; 344 goto errout_locked; 345 } 346 347 if (genl_family_find_byid(family->id)) { 348 err = -EEXIST; 349 goto errout_locked; 350 } 351 352 if (family->id == GENL_ID_GENERATE) { 353 u16 newid = genl_generate_id(); 354 355 if (!newid) { 356 err = -ENOMEM; 357 goto errout_locked; 358 } 359 360 family->id = newid; 361 } 362 363 if (family->maxattr) { 364 family->attrbuf = kmalloc((family->maxattr+1) * 365 sizeof(struct nlattr *), GFP_KERNEL); 366 if (family->attrbuf == NULL) { 367 err = -ENOMEM; 368 goto errout_locked; 369 } 370 } else 371 family->attrbuf = NULL; 372 373 list_add_tail(&family->family_list, genl_family_chain(family->id)); 374 genl_unlock(); 375 376 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family); 377 378 return 0; 379 380 errout_locked: 381 genl_unlock(); 382 errout: 383 return err; 384 } 385 386 /** 387 * genl_unregister_family - unregister generic netlink family 388 * @family: generic netlink family 389 * 390 * Unregisters the specified family. 391 * 392 * Returns 0 on success or a negative error code. 393 */ 394 int genl_unregister_family(struct genl_family *family) 395 { 396 struct genl_family *rc; 397 398 genl_lock(); 399 400 genl_unregister_mc_groups(family); 401 402 list_for_each_entry(rc, genl_family_chain(family->id), family_list) { 403 if (family->id != rc->id || strcmp(rc->name, family->name)) 404 continue; 405 406 list_del(&rc->family_list); 407 INIT_LIST_HEAD(&family->ops_list); 408 genl_unlock(); 409 410 kfree(family->attrbuf); 411 genl_ctrl_event(CTRL_CMD_DELFAMILY, family); 412 return 0; 413 } 414 415 genl_unlock(); 416 417 return -ENOENT; 418 } 419 420 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 421 { 422 struct genl_ops *ops; 423 struct genl_family *family; 424 struct genl_info info; 425 struct genlmsghdr *hdr = nlmsg_data(nlh); 426 int hdrlen, err; 427 428 family = genl_family_find_byid(nlh->nlmsg_type); 429 if (family == NULL) 430 return -ENOENT; 431 432 hdrlen = GENL_HDRLEN + family->hdrsize; 433 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 434 return -EINVAL; 435 436 ops = genl_get_cmd(hdr->cmd, family); 437 if (ops == NULL) 438 return -EOPNOTSUPP; 439 440 if ((ops->flags & GENL_ADMIN_PERM) && 441 security_netlink_recv(skb, CAP_NET_ADMIN)) 442 return -EPERM; 443 444 if (nlh->nlmsg_flags & NLM_F_DUMP) { 445 if (ops->dumpit == NULL) 446 return -EOPNOTSUPP; 447 448 genl_unlock(); 449 err = netlink_dump_start(genl_sock, skb, nlh, 450 ops->dumpit, ops->done); 451 genl_lock(); 452 return err; 453 } 454 455 if (ops->doit == NULL) 456 return -EOPNOTSUPP; 457 458 if (family->attrbuf) { 459 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr, 460 ops->policy); 461 if (err < 0) 462 return err; 463 } 464 465 info.snd_seq = nlh->nlmsg_seq; 466 info.snd_pid = NETLINK_CB(skb).pid; 467 info.nlhdr = nlh; 468 info.genlhdr = nlmsg_data(nlh); 469 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 470 info.attrs = family->attrbuf; 471 472 return ops->doit(skb, &info); 473 } 474 475 static void genl_rcv(struct sk_buff *skb) 476 { 477 genl_lock(); 478 netlink_rcv_skb(skb, &genl_rcv_msg); 479 genl_unlock(); 480 } 481 482 /************************************************************************** 483 * Controller 484 **************************************************************************/ 485 486 static struct genl_family genl_ctrl = { 487 .id = GENL_ID_CTRL, 488 .name = "nlctrl", 489 .version = 0x2, 490 .maxattr = CTRL_ATTR_MAX, 491 }; 492 493 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq, 494 u32 flags, struct sk_buff *skb, u8 cmd) 495 { 496 void *hdr; 497 498 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); 499 if (hdr == NULL) 500 return -1; 501 502 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name); 503 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id); 504 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version); 505 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize); 506 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr); 507 508 if (!list_empty(&family->ops_list)) { 509 struct nlattr *nla_ops; 510 struct genl_ops *ops; 511 int idx = 1; 512 513 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 514 if (nla_ops == NULL) 515 goto nla_put_failure; 516 517 list_for_each_entry(ops, &family->ops_list, ops_list) { 518 struct nlattr *nest; 519 520 nest = nla_nest_start(skb, idx++); 521 if (nest == NULL) 522 goto nla_put_failure; 523 524 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd); 525 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags); 526 527 nla_nest_end(skb, nest); 528 } 529 530 nla_nest_end(skb, nla_ops); 531 } 532 533 if (!list_empty(&family->mcast_groups)) { 534 struct genl_multicast_group *grp; 535 struct nlattr *nla_grps; 536 int idx = 1; 537 538 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 539 if (nla_grps == NULL) 540 goto nla_put_failure; 541 542 list_for_each_entry(grp, &family->mcast_groups, list) { 543 struct nlattr *nest; 544 545 nest = nla_nest_start(skb, idx++); 546 if (nest == NULL) 547 goto nla_put_failure; 548 549 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); 550 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, 551 grp->name); 552 553 nla_nest_end(skb, nest); 554 } 555 nla_nest_end(skb, nla_grps); 556 } 557 558 return genlmsg_end(skb, hdr); 559 560 nla_put_failure: 561 genlmsg_cancel(skb, hdr); 562 return -EMSGSIZE; 563 } 564 565 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid, 566 u32 seq, u32 flags, struct sk_buff *skb, 567 u8 cmd) 568 { 569 void *hdr; 570 struct nlattr *nla_grps; 571 struct nlattr *nest; 572 573 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); 574 if (hdr == NULL) 575 return -1; 576 577 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name); 578 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id); 579 580 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 581 if (nla_grps == NULL) 582 goto nla_put_failure; 583 584 nest = nla_nest_start(skb, 1); 585 if (nest == NULL) 586 goto nla_put_failure; 587 588 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); 589 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, 590 grp->name); 591 592 nla_nest_end(skb, nest); 593 nla_nest_end(skb, nla_grps); 594 595 return genlmsg_end(skb, hdr); 596 597 nla_put_failure: 598 genlmsg_cancel(skb, hdr); 599 return -EMSGSIZE; 600 } 601 602 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 603 { 604 605 int i, n = 0; 606 struct genl_family *rt; 607 int chains_to_skip = cb->args[0]; 608 int fams_to_skip = cb->args[1]; 609 610 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 611 if (i < chains_to_skip) 612 continue; 613 n = 0; 614 list_for_each_entry(rt, genl_family_chain(i), family_list) { 615 if (++n < fams_to_skip) 616 continue; 617 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid, 618 cb->nlh->nlmsg_seq, NLM_F_MULTI, 619 skb, CTRL_CMD_NEWFAMILY) < 0) 620 goto errout; 621 } 622 623 fams_to_skip = 0; 624 } 625 626 errout: 627 cb->args[0] = i; 628 cb->args[1] = n; 629 630 return skb->len; 631 } 632 633 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 634 u32 pid, int seq, u8 cmd) 635 { 636 struct sk_buff *skb; 637 int err; 638 639 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 640 if (skb == NULL) 641 return ERR_PTR(-ENOBUFS); 642 643 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd); 644 if (err < 0) { 645 nlmsg_free(skb); 646 return ERR_PTR(err); 647 } 648 649 return skb; 650 } 651 652 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp, 653 u32 pid, int seq, u8 cmd) 654 { 655 struct sk_buff *skb; 656 int err; 657 658 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 659 if (skb == NULL) 660 return ERR_PTR(-ENOBUFS); 661 662 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd); 663 if (err < 0) { 664 nlmsg_free(skb); 665 return ERR_PTR(err); 666 } 667 668 return skb; 669 } 670 671 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 672 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 673 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 674 .len = GENL_NAMSIZ - 1 }, 675 }; 676 677 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 678 { 679 struct sk_buff *msg; 680 struct genl_family *res = NULL; 681 int err = -EINVAL; 682 683 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 684 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 685 res = genl_family_find_byid(id); 686 } 687 688 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 689 char *name; 690 691 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 692 res = genl_family_find_byname(name); 693 } 694 695 if (res == NULL) { 696 err = -ENOENT; 697 goto errout; 698 } 699 700 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq, 701 CTRL_CMD_NEWFAMILY); 702 if (IS_ERR(msg)) { 703 err = PTR_ERR(msg); 704 goto errout; 705 } 706 707 err = genlmsg_reply(msg, info); 708 errout: 709 return err; 710 } 711 712 static int genl_ctrl_event(int event, void *data) 713 { 714 struct sk_buff *msg; 715 716 if (genl_sock == NULL) 717 return 0; 718 719 switch (event) { 720 case CTRL_CMD_NEWFAMILY: 721 case CTRL_CMD_DELFAMILY: 722 msg = ctrl_build_family_msg(data, 0, 0, event); 723 if (IS_ERR(msg)) 724 return PTR_ERR(msg); 725 726 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL); 727 break; 728 case CTRL_CMD_NEWMCAST_GRP: 729 case CTRL_CMD_DELMCAST_GRP: 730 msg = ctrl_build_mcgrp_msg(data, 0, 0, event); 731 if (IS_ERR(msg)) 732 return PTR_ERR(msg); 733 734 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL); 735 break; 736 } 737 738 return 0; 739 } 740 741 static struct genl_ops genl_ctrl_ops = { 742 .cmd = CTRL_CMD_GETFAMILY, 743 .doit = ctrl_getfamily, 744 .dumpit = ctrl_dumpfamily, 745 .policy = ctrl_policy, 746 }; 747 748 static struct genl_multicast_group notify_grp = { 749 .name = "notify", 750 }; 751 752 static int __init genl_init(void) 753 { 754 int i, err; 755 756 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 757 INIT_LIST_HEAD(&family_ht[i]); 758 759 err = genl_register_family(&genl_ctrl); 760 if (err < 0) 761 goto errout; 762 763 err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops); 764 if (err < 0) 765 goto errout_register; 766 767 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV); 768 769 /* we'll bump the group number right afterwards */ 770 genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0, 771 genl_rcv, &genl_mutex, THIS_MODULE); 772 if (genl_sock == NULL) 773 panic("GENL: Cannot initialize generic netlink\n"); 774 775 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp); 776 if (err < 0) 777 goto errout_register; 778 779 return 0; 780 781 errout_register: 782 genl_unregister_family(&genl_ctrl); 783 errout: 784 panic("GENL: Cannot register controller: %d\n", err); 785 } 786 787 subsys_initcall(genl_init); 788 789 EXPORT_SYMBOL(genl_sock); 790 EXPORT_SYMBOL(genl_register_ops); 791 EXPORT_SYMBOL(genl_unregister_ops); 792 EXPORT_SYMBOL(genl_register_family); 793 EXPORT_SYMBOL(genl_unregister_family); 794