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 } 228 229 static void genl_unregister_mc_groups(struct genl_family *family) 230 { 231 struct genl_multicast_group *grp, *tmp; 232 233 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list) 234 __genl_unregister_mc_group(family, grp); 235 } 236 237 /** 238 * genl_register_ops - register generic netlink operations 239 * @family: generic netlink family 240 * @ops: operations to be registered 241 * 242 * Registers the specified operations and assigns them to the specified 243 * family. Either a doit or dumpit callback must be specified or the 244 * operation will fail. Only one operation structure per command 245 * identifier may be registered. 246 * 247 * See include/net/genetlink.h for more documenation on the operations 248 * structure. 249 * 250 * Returns 0 on success or a negative error code. 251 */ 252 int genl_register_ops(struct genl_family *family, struct genl_ops *ops) 253 { 254 int err = -EINVAL; 255 256 if (ops->dumpit == NULL && ops->doit == NULL) 257 goto errout; 258 259 if (genl_get_cmd(ops->cmd, family)) { 260 err = -EEXIST; 261 goto errout; 262 } 263 264 if (ops->dumpit) 265 ops->flags |= GENL_CMD_CAP_DUMP; 266 if (ops->doit) 267 ops->flags |= GENL_CMD_CAP_DO; 268 if (ops->policy) 269 ops->flags |= GENL_CMD_CAP_HASPOL; 270 271 genl_lock(); 272 list_add_tail(&ops->ops_list, &family->ops_list); 273 genl_unlock(); 274 275 genl_ctrl_event(CTRL_CMD_NEWOPS, ops); 276 err = 0; 277 errout: 278 return err; 279 } 280 281 /** 282 * genl_unregister_ops - unregister generic netlink operations 283 * @family: generic netlink family 284 * @ops: operations to be unregistered 285 * 286 * Unregisters the specified operations and unassigns them from the 287 * specified family. The operation blocks until the current message 288 * processing has finished and doesn't start again until the 289 * unregister process has finished. 290 * 291 * Note: It is not necessary to unregister all operations before 292 * unregistering the family, unregistering the family will cause 293 * all assigned operations to be unregistered automatically. 294 * 295 * Returns 0 on success or a negative error code. 296 */ 297 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops) 298 { 299 struct genl_ops *rc; 300 301 genl_lock(); 302 list_for_each_entry(rc, &family->ops_list, ops_list) { 303 if (rc == ops) { 304 list_del(&ops->ops_list); 305 genl_unlock(); 306 genl_ctrl_event(CTRL_CMD_DELOPS, ops); 307 return 0; 308 } 309 } 310 genl_unlock(); 311 312 return -ENOENT; 313 } 314 315 /** 316 * genl_register_family - register a generic netlink family 317 * @family: generic netlink family 318 * 319 * Registers the specified family after validating it first. Only one 320 * family may be registered with the same family name or identifier. 321 * The family id may equal GENL_ID_GENERATE causing an unique id to 322 * be automatically generated and assigned. 323 * 324 * Return 0 on success or a negative error code. 325 */ 326 int genl_register_family(struct genl_family *family) 327 { 328 int err = -EINVAL; 329 330 if (family->id && family->id < GENL_MIN_ID) 331 goto errout; 332 333 if (family->id > GENL_MAX_ID) 334 goto errout; 335 336 INIT_LIST_HEAD(&family->ops_list); 337 INIT_LIST_HEAD(&family->mcast_groups); 338 339 genl_lock(); 340 341 if (genl_family_find_byname(family->name)) { 342 err = -EEXIST; 343 goto errout_locked; 344 } 345 346 if (genl_family_find_byid(family->id)) { 347 err = -EEXIST; 348 goto errout_locked; 349 } 350 351 if (family->id == GENL_ID_GENERATE) { 352 u16 newid = genl_generate_id(); 353 354 if (!newid) { 355 err = -ENOMEM; 356 goto errout_locked; 357 } 358 359 family->id = newid; 360 } 361 362 if (family->maxattr) { 363 family->attrbuf = kmalloc((family->maxattr+1) * 364 sizeof(struct nlattr *), GFP_KERNEL); 365 if (family->attrbuf == NULL) { 366 err = -ENOMEM; 367 goto errout_locked; 368 } 369 } else 370 family->attrbuf = NULL; 371 372 list_add_tail(&family->family_list, genl_family_chain(family->id)); 373 genl_unlock(); 374 375 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family); 376 377 return 0; 378 379 errout_locked: 380 genl_unlock(); 381 errout: 382 return err; 383 } 384 385 /** 386 * genl_unregister_family - unregister generic netlink family 387 * @family: generic netlink family 388 * 389 * Unregisters the specified family. 390 * 391 * Returns 0 on success or a negative error code. 392 */ 393 int genl_unregister_family(struct genl_family *family) 394 { 395 struct genl_family *rc; 396 397 genl_lock(); 398 399 genl_unregister_mc_groups(family); 400 401 list_for_each_entry(rc, genl_family_chain(family->id), family_list) { 402 if (family->id != rc->id || strcmp(rc->name, family->name)) 403 continue; 404 405 list_del(&rc->family_list); 406 INIT_LIST_HEAD(&family->ops_list); 407 genl_unlock(); 408 409 kfree(family->attrbuf); 410 genl_ctrl_event(CTRL_CMD_DELFAMILY, family); 411 return 0; 412 } 413 414 genl_unlock(); 415 416 return -ENOENT; 417 } 418 419 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 420 { 421 struct genl_ops *ops; 422 struct genl_family *family; 423 struct genl_info info; 424 struct genlmsghdr *hdr = nlmsg_data(nlh); 425 int hdrlen, err; 426 427 family = genl_family_find_byid(nlh->nlmsg_type); 428 if (family == NULL) 429 return -ENOENT; 430 431 hdrlen = GENL_HDRLEN + family->hdrsize; 432 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 433 return -EINVAL; 434 435 ops = genl_get_cmd(hdr->cmd, family); 436 if (ops == NULL) 437 return -EOPNOTSUPP; 438 439 if ((ops->flags & GENL_ADMIN_PERM) && 440 security_netlink_recv(skb, CAP_NET_ADMIN)) 441 return -EPERM; 442 443 if (nlh->nlmsg_flags & NLM_F_DUMP) { 444 if (ops->dumpit == NULL) 445 return -EOPNOTSUPP; 446 447 genl_unlock(); 448 err = netlink_dump_start(genl_sock, skb, nlh, 449 ops->dumpit, ops->done); 450 genl_lock(); 451 return err; 452 } 453 454 if (ops->doit == NULL) 455 return -EOPNOTSUPP; 456 457 if (family->attrbuf) { 458 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr, 459 ops->policy); 460 if (err < 0) 461 return err; 462 } 463 464 info.snd_seq = nlh->nlmsg_seq; 465 info.snd_pid = NETLINK_CB(skb).pid; 466 info.nlhdr = nlh; 467 info.genlhdr = nlmsg_data(nlh); 468 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 469 info.attrs = family->attrbuf; 470 471 return ops->doit(skb, &info); 472 } 473 474 static void genl_rcv(struct sk_buff *skb) 475 { 476 genl_lock(); 477 netlink_rcv_skb(skb, &genl_rcv_msg); 478 genl_unlock(); 479 } 480 481 /************************************************************************** 482 * Controller 483 **************************************************************************/ 484 485 static struct genl_family genl_ctrl = { 486 .id = GENL_ID_CTRL, 487 .name = "nlctrl", 488 .version = 0x2, 489 .maxattr = CTRL_ATTR_MAX, 490 }; 491 492 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq, 493 u32 flags, struct sk_buff *skb, u8 cmd) 494 { 495 void *hdr; 496 497 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); 498 if (hdr == NULL) 499 return -1; 500 501 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name); 502 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id); 503 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version); 504 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize); 505 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr); 506 507 if (!list_empty(&family->ops_list)) { 508 struct nlattr *nla_ops; 509 struct genl_ops *ops; 510 int idx = 1; 511 512 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 513 if (nla_ops == NULL) 514 goto nla_put_failure; 515 516 list_for_each_entry(ops, &family->ops_list, ops_list) { 517 struct nlattr *nest; 518 519 nest = nla_nest_start(skb, idx++); 520 if (nest == NULL) 521 goto nla_put_failure; 522 523 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd); 524 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags); 525 526 nla_nest_end(skb, nest); 527 } 528 529 nla_nest_end(skb, nla_ops); 530 } 531 532 if (!list_empty(&family->mcast_groups)) { 533 struct genl_multicast_group *grp; 534 struct nlattr *nla_grps; 535 int idx = 1; 536 537 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 538 if (nla_grps == NULL) 539 goto nla_put_failure; 540 541 list_for_each_entry(grp, &family->mcast_groups, list) { 542 struct nlattr *nest; 543 544 nest = nla_nest_start(skb, idx++); 545 if (nest == NULL) 546 goto nla_put_failure; 547 548 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); 549 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, 550 grp->name); 551 552 nla_nest_end(skb, nest); 553 } 554 nla_nest_end(skb, nla_grps); 555 } 556 557 return genlmsg_end(skb, hdr); 558 559 nla_put_failure: 560 genlmsg_cancel(skb, hdr); 561 return -EMSGSIZE; 562 } 563 564 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid, 565 u32 seq, u32 flags, struct sk_buff *skb, 566 u8 cmd) 567 { 568 void *hdr; 569 struct nlattr *nla_grps; 570 struct nlattr *nest; 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, grp->family->name); 577 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id); 578 579 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 580 if (nla_grps == NULL) 581 goto nla_put_failure; 582 583 nest = nla_nest_start(skb, 1); 584 if (nest == NULL) 585 goto nla_put_failure; 586 587 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); 588 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, 589 grp->name); 590 591 nla_nest_end(skb, nest); 592 nla_nest_end(skb, nla_grps); 593 594 return genlmsg_end(skb, hdr); 595 596 nla_put_failure: 597 genlmsg_cancel(skb, hdr); 598 return -EMSGSIZE; 599 } 600 601 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 602 { 603 604 int i, n = 0; 605 struct genl_family *rt; 606 int chains_to_skip = cb->args[0]; 607 int fams_to_skip = cb->args[1]; 608 609 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 610 if (i < chains_to_skip) 611 continue; 612 n = 0; 613 list_for_each_entry(rt, genl_family_chain(i), family_list) { 614 if (++n < fams_to_skip) 615 continue; 616 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid, 617 cb->nlh->nlmsg_seq, NLM_F_MULTI, 618 skb, CTRL_CMD_NEWFAMILY) < 0) 619 goto errout; 620 } 621 622 fams_to_skip = 0; 623 } 624 625 errout: 626 cb->args[0] = i; 627 cb->args[1] = n; 628 629 return skb->len; 630 } 631 632 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 633 u32 pid, int seq, u8 cmd) 634 { 635 struct sk_buff *skb; 636 int err; 637 638 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 639 if (skb == NULL) 640 return ERR_PTR(-ENOBUFS); 641 642 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd); 643 if (err < 0) { 644 nlmsg_free(skb); 645 return ERR_PTR(err); 646 } 647 648 return skb; 649 } 650 651 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp, 652 u32 pid, int seq, u8 cmd) 653 { 654 struct sk_buff *skb; 655 int err; 656 657 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 658 if (skb == NULL) 659 return ERR_PTR(-ENOBUFS); 660 661 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd); 662 if (err < 0) { 663 nlmsg_free(skb); 664 return ERR_PTR(err); 665 } 666 667 return skb; 668 } 669 670 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 671 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 672 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 673 .len = GENL_NAMSIZ - 1 }, 674 }; 675 676 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 677 { 678 struct sk_buff *msg; 679 struct genl_family *res = NULL; 680 int err = -EINVAL; 681 682 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 683 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 684 res = genl_family_find_byid(id); 685 } 686 687 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 688 char *name; 689 690 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 691 res = genl_family_find_byname(name); 692 } 693 694 if (res == NULL) { 695 err = -ENOENT; 696 goto errout; 697 } 698 699 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq, 700 CTRL_CMD_NEWFAMILY); 701 if (IS_ERR(msg)) { 702 err = PTR_ERR(msg); 703 goto errout; 704 } 705 706 err = genlmsg_reply(msg, info); 707 errout: 708 return err; 709 } 710 711 static int genl_ctrl_event(int event, void *data) 712 { 713 struct sk_buff *msg; 714 715 if (genl_sock == NULL) 716 return 0; 717 718 switch (event) { 719 case CTRL_CMD_NEWFAMILY: 720 case CTRL_CMD_DELFAMILY: 721 msg = ctrl_build_family_msg(data, 0, 0, event); 722 if (IS_ERR(msg)) 723 return PTR_ERR(msg); 724 725 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL); 726 break; 727 case CTRL_CMD_NEWMCAST_GRP: 728 case CTRL_CMD_DELMCAST_GRP: 729 msg = ctrl_build_mcgrp_msg(data, 0, 0, event); 730 if (IS_ERR(msg)) 731 return PTR_ERR(msg); 732 733 genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL); 734 break; 735 } 736 737 return 0; 738 } 739 740 static struct genl_ops genl_ctrl_ops = { 741 .cmd = CTRL_CMD_GETFAMILY, 742 .doit = ctrl_getfamily, 743 .dumpit = ctrl_dumpfamily, 744 .policy = ctrl_policy, 745 }; 746 747 static struct genl_multicast_group notify_grp = { 748 .name = "notify", 749 }; 750 751 static int __init genl_init(void) 752 { 753 int i, err; 754 755 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 756 INIT_LIST_HEAD(&family_ht[i]); 757 758 err = genl_register_family(&genl_ctrl); 759 if (err < 0) 760 goto errout; 761 762 err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops); 763 if (err < 0) 764 goto errout_register; 765 766 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV); 767 768 /* we'll bump the group number right afterwards */ 769 genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0, 770 genl_rcv, &genl_mutex, THIS_MODULE); 771 if (genl_sock == NULL) 772 panic("GENL: Cannot initialize generic netlink\n"); 773 774 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp); 775 if (err < 0) 776 goto errout_register; 777 778 return 0; 779 780 errout_register: 781 genl_unregister_family(&genl_ctrl); 782 errout: 783 panic("GENL: Cannot register controller: %d\n", err); 784 } 785 786 subsys_initcall(genl_init); 787 788 EXPORT_SYMBOL(genl_sock); 789 EXPORT_SYMBOL(genl_register_ops); 790 EXPORT_SYMBOL(genl_unregister_ops); 791 EXPORT_SYMBOL(genl_register_family); 792 EXPORT_SYMBOL(genl_unregister_family); 793