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 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ 22 23 static inline void genl_lock(void) 24 { 25 mutex_lock(&genl_mutex); 26 } 27 28 static inline void genl_unlock(void) 29 { 30 mutex_unlock(&genl_mutex); 31 } 32 33 #define GENL_FAM_TAB_SIZE 16 34 #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) 35 36 static struct list_head family_ht[GENL_FAM_TAB_SIZE]; 37 /* 38 * Bitmap of multicast groups that are currently in use. 39 * 40 * To avoid an allocation at boot of just one unsigned long, 41 * declare it global instead. 42 * Bit 0 is marked as already used since group 0 is invalid. 43 */ 44 static unsigned long mc_group_start = 0x1; 45 static unsigned long *mc_groups = &mc_group_start; 46 static unsigned long mc_groups_longs = 1; 47 48 static int genl_ctrl_event(int event, void *data); 49 50 static inline unsigned int genl_family_hash(unsigned int id) 51 { 52 return id & GENL_FAM_TAB_MASK; 53 } 54 55 static inline struct list_head *genl_family_chain(unsigned int id) 56 { 57 return &family_ht[genl_family_hash(id)]; 58 } 59 60 static struct genl_family *genl_family_find_byid(unsigned int id) 61 { 62 struct genl_family *f; 63 64 list_for_each_entry(f, genl_family_chain(id), family_list) 65 if (f->id == id) 66 return f; 67 68 return NULL; 69 } 70 71 static struct genl_family *genl_family_find_byname(char *name) 72 { 73 struct genl_family *f; 74 int i; 75 76 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 77 list_for_each_entry(f, genl_family_chain(i), family_list) 78 if (strcmp(f->name, name) == 0) 79 return f; 80 81 return NULL; 82 } 83 84 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) 85 { 86 struct genl_ops *ops; 87 88 list_for_each_entry(ops, &family->ops_list, ops_list) 89 if (ops->cmd == cmd) 90 return ops; 91 92 return NULL; 93 } 94 95 /* Of course we are going to have problems once we hit 96 * 2^16 alive types, but that can only happen by year 2K 97 */ 98 static inline u16 genl_generate_id(void) 99 { 100 static u16 id_gen_idx; 101 int overflowed = 0; 102 103 do { 104 if (id_gen_idx == 0) 105 id_gen_idx = GENL_MIN_ID; 106 107 if (++id_gen_idx > GENL_MAX_ID) { 108 if (!overflowed) { 109 overflowed = 1; 110 id_gen_idx = 0; 111 continue; 112 } else 113 return 0; 114 } 115 116 } while (genl_family_find_byid(id_gen_idx)); 117 118 return id_gen_idx; 119 } 120 121 static struct genl_multicast_group notify_grp; 122 123 /** 124 * genl_register_mc_group - register a multicast group 125 * 126 * Registers the specified multicast group and notifies userspace 127 * about the new group. 128 * 129 * Returns 0 on success or a negative error code. 130 * 131 * @family: The generic netlink family the group shall be registered for. 132 * @grp: The group to register, must have a name. 133 */ 134 int genl_register_mc_group(struct genl_family *family, 135 struct genl_multicast_group *grp) 136 { 137 int id; 138 unsigned long *new_groups; 139 int err = 0; 140 141 BUG_ON(grp->name[0] == '\0'); 142 143 genl_lock(); 144 145 /* special-case our own group */ 146 if (grp == ¬ify_grp) 147 id = GENL_ID_CTRL; 148 else 149 id = find_first_zero_bit(mc_groups, 150 mc_groups_longs * BITS_PER_LONG); 151 152 153 if (id >= mc_groups_longs * BITS_PER_LONG) { 154 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long); 155 156 if (mc_groups == &mc_group_start) { 157 new_groups = kzalloc(nlen, GFP_KERNEL); 158 if (!new_groups) { 159 err = -ENOMEM; 160 goto out; 161 } 162 mc_groups = new_groups; 163 *mc_groups = mc_group_start; 164 } else { 165 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL); 166 if (!new_groups) { 167 err = -ENOMEM; 168 goto out; 169 } 170 mc_groups = new_groups; 171 mc_groups[mc_groups_longs] = 0; 172 } 173 mc_groups_longs++; 174 } 175 176 if (family->netnsok) { 177 struct net *net; 178 179 rcu_read_lock(); 180 for_each_net_rcu(net) { 181 err = netlink_change_ngroups(net->genl_sock, 182 mc_groups_longs * BITS_PER_LONG); 183 if (err) { 184 /* 185 * No need to roll back, can only fail if 186 * memory allocation fails and then the 187 * number of _possible_ groups has been 188 * increased on some sockets which is ok. 189 */ 190 rcu_read_unlock(); 191 goto out; 192 } 193 } 194 rcu_read_unlock(); 195 } else { 196 err = netlink_change_ngroups(init_net.genl_sock, 197 mc_groups_longs * BITS_PER_LONG); 198 if (err) 199 goto out; 200 } 201 202 grp->id = id; 203 set_bit(id, mc_groups); 204 list_add_tail(&grp->list, &family->mcast_groups); 205 grp->family = family; 206 207 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp); 208 out: 209 genl_unlock(); 210 return err; 211 } 212 EXPORT_SYMBOL(genl_register_mc_group); 213 214 static void __genl_unregister_mc_group(struct genl_family *family, 215 struct genl_multicast_group *grp) 216 { 217 struct net *net; 218 BUG_ON(grp->family != family); 219 220 rcu_read_lock(); 221 for_each_net_rcu(net) 222 netlink_clear_multicast_users(net->genl_sock, grp->id); 223 rcu_read_unlock(); 224 225 clear_bit(grp->id, mc_groups); 226 list_del(&grp->list); 227 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp); 228 grp->id = 0; 229 grp->family = NULL; 230 } 231 232 /** 233 * genl_unregister_mc_group - unregister a multicast group 234 * 235 * Unregisters the specified multicast group and notifies userspace 236 * about it. All current listeners on the group are removed. 237 * 238 * Note: It is not necessary to unregister all multicast groups before 239 * unregistering the family, unregistering the family will cause 240 * all assigned multicast groups to be unregistered automatically. 241 * 242 * @family: Generic netlink family the group belongs to. 243 * @grp: The group to unregister, must have been registered successfully 244 * previously. 245 */ 246 void genl_unregister_mc_group(struct genl_family *family, 247 struct genl_multicast_group *grp) 248 { 249 genl_lock(); 250 __genl_unregister_mc_group(family, grp); 251 genl_unlock(); 252 } 253 EXPORT_SYMBOL(genl_unregister_mc_group); 254 255 static void genl_unregister_mc_groups(struct genl_family *family) 256 { 257 struct genl_multicast_group *grp, *tmp; 258 259 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list) 260 __genl_unregister_mc_group(family, grp); 261 } 262 263 /** 264 * genl_register_ops - register generic netlink operations 265 * @family: generic netlink family 266 * @ops: operations to be registered 267 * 268 * Registers the specified operations and assigns them to the specified 269 * family. Either a doit or dumpit callback must be specified or the 270 * operation will fail. Only one operation structure per command 271 * identifier may be registered. 272 * 273 * See include/net/genetlink.h for more documenation on the operations 274 * structure. 275 * 276 * Returns 0 on success or a negative error code. 277 */ 278 int genl_register_ops(struct genl_family *family, struct genl_ops *ops) 279 { 280 int err = -EINVAL; 281 282 if (ops->dumpit == NULL && ops->doit == NULL) 283 goto errout; 284 285 if (genl_get_cmd(ops->cmd, family)) { 286 err = -EEXIST; 287 goto errout; 288 } 289 290 if (ops->dumpit) 291 ops->flags |= GENL_CMD_CAP_DUMP; 292 if (ops->doit) 293 ops->flags |= GENL_CMD_CAP_DO; 294 if (ops->policy) 295 ops->flags |= GENL_CMD_CAP_HASPOL; 296 297 genl_lock(); 298 list_add_tail(&ops->ops_list, &family->ops_list); 299 genl_unlock(); 300 301 genl_ctrl_event(CTRL_CMD_NEWOPS, ops); 302 err = 0; 303 errout: 304 return err; 305 } 306 307 /** 308 * genl_unregister_ops - unregister generic netlink operations 309 * @family: generic netlink family 310 * @ops: operations to be unregistered 311 * 312 * Unregisters the specified operations and unassigns them from the 313 * specified family. The operation blocks until the current message 314 * processing has finished and doesn't start again until the 315 * unregister process has finished. 316 * 317 * Note: It is not necessary to unregister all operations before 318 * unregistering the family, unregistering the family will cause 319 * all assigned operations to be unregistered automatically. 320 * 321 * Returns 0 on success or a negative error code. 322 */ 323 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops) 324 { 325 struct genl_ops *rc; 326 327 genl_lock(); 328 list_for_each_entry(rc, &family->ops_list, ops_list) { 329 if (rc == ops) { 330 list_del(&ops->ops_list); 331 genl_unlock(); 332 genl_ctrl_event(CTRL_CMD_DELOPS, ops); 333 return 0; 334 } 335 } 336 genl_unlock(); 337 338 return -ENOENT; 339 } 340 341 /** 342 * genl_register_family - register a generic netlink family 343 * @family: generic netlink family 344 * 345 * Registers the specified family after validating it first. Only one 346 * family may be registered with the same family name or identifier. 347 * The family id may equal GENL_ID_GENERATE causing an unique id to 348 * be automatically generated and assigned. 349 * 350 * Return 0 on success or a negative error code. 351 */ 352 int genl_register_family(struct genl_family *family) 353 { 354 int err = -EINVAL; 355 356 if (family->id && family->id < GENL_MIN_ID) 357 goto errout; 358 359 if (family->id > GENL_MAX_ID) 360 goto errout; 361 362 INIT_LIST_HEAD(&family->ops_list); 363 INIT_LIST_HEAD(&family->mcast_groups); 364 365 genl_lock(); 366 367 if (genl_family_find_byname(family->name)) { 368 err = -EEXIST; 369 goto errout_locked; 370 } 371 372 if (genl_family_find_byid(family->id)) { 373 err = -EEXIST; 374 goto errout_locked; 375 } 376 377 if (family->id == GENL_ID_GENERATE) { 378 u16 newid = genl_generate_id(); 379 380 if (!newid) { 381 err = -ENOMEM; 382 goto errout_locked; 383 } 384 385 family->id = newid; 386 } 387 388 if (family->maxattr) { 389 family->attrbuf = kmalloc((family->maxattr+1) * 390 sizeof(struct nlattr *), GFP_KERNEL); 391 if (family->attrbuf == NULL) { 392 err = -ENOMEM; 393 goto errout_locked; 394 } 395 } else 396 family->attrbuf = NULL; 397 398 list_add_tail(&family->family_list, genl_family_chain(family->id)); 399 genl_unlock(); 400 401 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family); 402 403 return 0; 404 405 errout_locked: 406 genl_unlock(); 407 errout: 408 return err; 409 } 410 411 /** 412 * genl_register_family_with_ops - register a generic netlink family 413 * @family: generic netlink family 414 * @ops: operations to be registered 415 * @n_ops: number of elements to register 416 * 417 * Registers the specified family and operations from the specified table. 418 * Only one family may be registered with the same family name or identifier. 419 * 420 * The family id may equal GENL_ID_GENERATE causing an unique id to 421 * be automatically generated and assigned. 422 * 423 * Either a doit or dumpit callback must be specified for every registered 424 * operation or the function will fail. Only one operation structure per 425 * command identifier may be registered. 426 * 427 * See include/net/genetlink.h for more documenation on the operations 428 * structure. 429 * 430 * This is equivalent to calling genl_register_family() followed by 431 * genl_register_ops() for every operation entry in the table taking 432 * care to unregister the family on error path. 433 * 434 * Return 0 on success or a negative error code. 435 */ 436 int genl_register_family_with_ops(struct genl_family *family, 437 struct genl_ops *ops, size_t n_ops) 438 { 439 int err, i; 440 441 err = genl_register_family(family); 442 if (err) 443 return err; 444 445 for (i = 0; i < n_ops; ++i, ++ops) { 446 err = genl_register_ops(family, ops); 447 if (err) 448 goto err_out; 449 } 450 return 0; 451 err_out: 452 genl_unregister_family(family); 453 return err; 454 } 455 EXPORT_SYMBOL(genl_register_family_with_ops); 456 457 /** 458 * genl_unregister_family - unregister generic netlink family 459 * @family: generic netlink family 460 * 461 * Unregisters the specified family. 462 * 463 * Returns 0 on success or a negative error code. 464 */ 465 int genl_unregister_family(struct genl_family *family) 466 { 467 struct genl_family *rc; 468 469 genl_lock(); 470 471 genl_unregister_mc_groups(family); 472 473 list_for_each_entry(rc, genl_family_chain(family->id), family_list) { 474 if (family->id != rc->id || strcmp(rc->name, family->name)) 475 continue; 476 477 list_del(&rc->family_list); 478 INIT_LIST_HEAD(&family->ops_list); 479 genl_unlock(); 480 481 kfree(family->attrbuf); 482 genl_ctrl_event(CTRL_CMD_DELFAMILY, family); 483 return 0; 484 } 485 486 genl_unlock(); 487 488 return -ENOENT; 489 } 490 491 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 492 { 493 struct genl_ops *ops; 494 struct genl_family *family; 495 struct net *net = sock_net(skb->sk); 496 struct genl_info info; 497 struct genlmsghdr *hdr = nlmsg_data(nlh); 498 int hdrlen, err; 499 500 family = genl_family_find_byid(nlh->nlmsg_type); 501 if (family == NULL) 502 return -ENOENT; 503 504 /* this family doesn't exist in this netns */ 505 if (!family->netnsok && !net_eq(net, &init_net)) 506 return -ENOENT; 507 508 hdrlen = GENL_HDRLEN + family->hdrsize; 509 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 510 return -EINVAL; 511 512 ops = genl_get_cmd(hdr->cmd, family); 513 if (ops == NULL) 514 return -EOPNOTSUPP; 515 516 if ((ops->flags & GENL_ADMIN_PERM) && 517 security_netlink_recv(skb, CAP_NET_ADMIN)) 518 return -EPERM; 519 520 if (nlh->nlmsg_flags & NLM_F_DUMP) { 521 if (ops->dumpit == NULL) 522 return -EOPNOTSUPP; 523 524 genl_unlock(); 525 err = netlink_dump_start(net->genl_sock, skb, nlh, 526 ops->dumpit, ops->done); 527 genl_lock(); 528 return err; 529 } 530 531 if (ops->doit == NULL) 532 return -EOPNOTSUPP; 533 534 if (family->attrbuf) { 535 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr, 536 ops->policy); 537 if (err < 0) 538 return err; 539 } 540 541 info.snd_seq = nlh->nlmsg_seq; 542 info.snd_pid = NETLINK_CB(skb).pid; 543 info.nlhdr = nlh; 544 info.genlhdr = nlmsg_data(nlh); 545 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 546 info.attrs = family->attrbuf; 547 genl_info_net_set(&info, net); 548 549 return ops->doit(skb, &info); 550 } 551 552 static void genl_rcv(struct sk_buff *skb) 553 { 554 genl_lock(); 555 netlink_rcv_skb(skb, &genl_rcv_msg); 556 genl_unlock(); 557 } 558 559 /************************************************************************** 560 * Controller 561 **************************************************************************/ 562 563 static struct genl_family genl_ctrl = { 564 .id = GENL_ID_CTRL, 565 .name = "nlctrl", 566 .version = 0x2, 567 .maxattr = CTRL_ATTR_MAX, 568 .netnsok = true, 569 }; 570 571 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq, 572 u32 flags, struct sk_buff *skb, u8 cmd) 573 { 574 void *hdr; 575 576 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); 577 if (hdr == NULL) 578 return -1; 579 580 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name); 581 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id); 582 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version); 583 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize); 584 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr); 585 586 if (!list_empty(&family->ops_list)) { 587 struct nlattr *nla_ops; 588 struct genl_ops *ops; 589 int idx = 1; 590 591 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 592 if (nla_ops == NULL) 593 goto nla_put_failure; 594 595 list_for_each_entry(ops, &family->ops_list, ops_list) { 596 struct nlattr *nest; 597 598 nest = nla_nest_start(skb, idx++); 599 if (nest == NULL) 600 goto nla_put_failure; 601 602 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd); 603 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags); 604 605 nla_nest_end(skb, nest); 606 } 607 608 nla_nest_end(skb, nla_ops); 609 } 610 611 if (!list_empty(&family->mcast_groups)) { 612 struct genl_multicast_group *grp; 613 struct nlattr *nla_grps; 614 int idx = 1; 615 616 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 617 if (nla_grps == NULL) 618 goto nla_put_failure; 619 620 list_for_each_entry(grp, &family->mcast_groups, list) { 621 struct nlattr *nest; 622 623 nest = nla_nest_start(skb, idx++); 624 if (nest == NULL) 625 goto nla_put_failure; 626 627 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); 628 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, 629 grp->name); 630 631 nla_nest_end(skb, nest); 632 } 633 nla_nest_end(skb, nla_grps); 634 } 635 636 return genlmsg_end(skb, hdr); 637 638 nla_put_failure: 639 genlmsg_cancel(skb, hdr); 640 return -EMSGSIZE; 641 } 642 643 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid, 644 u32 seq, u32 flags, struct sk_buff *skb, 645 u8 cmd) 646 { 647 void *hdr; 648 struct nlattr *nla_grps; 649 struct nlattr *nest; 650 651 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); 652 if (hdr == NULL) 653 return -1; 654 655 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name); 656 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id); 657 658 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 659 if (nla_grps == NULL) 660 goto nla_put_failure; 661 662 nest = nla_nest_start(skb, 1); 663 if (nest == NULL) 664 goto nla_put_failure; 665 666 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); 667 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, 668 grp->name); 669 670 nla_nest_end(skb, nest); 671 nla_nest_end(skb, nla_grps); 672 673 return genlmsg_end(skb, hdr); 674 675 nla_put_failure: 676 genlmsg_cancel(skb, hdr); 677 return -EMSGSIZE; 678 } 679 680 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 681 { 682 683 int i, n = 0; 684 struct genl_family *rt; 685 struct net *net = sock_net(skb->sk); 686 int chains_to_skip = cb->args[0]; 687 int fams_to_skip = cb->args[1]; 688 689 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 690 if (i < chains_to_skip) 691 continue; 692 n = 0; 693 list_for_each_entry(rt, genl_family_chain(i), family_list) { 694 if (!rt->netnsok && !net_eq(net, &init_net)) 695 continue; 696 if (++n < fams_to_skip) 697 continue; 698 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid, 699 cb->nlh->nlmsg_seq, NLM_F_MULTI, 700 skb, CTRL_CMD_NEWFAMILY) < 0) 701 goto errout; 702 } 703 704 fams_to_skip = 0; 705 } 706 707 errout: 708 cb->args[0] = i; 709 cb->args[1] = n; 710 711 return skb->len; 712 } 713 714 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 715 u32 pid, int seq, u8 cmd) 716 { 717 struct sk_buff *skb; 718 int err; 719 720 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 721 if (skb == NULL) 722 return ERR_PTR(-ENOBUFS); 723 724 err = ctrl_fill_info(family, pid, seq, 0, skb, cmd); 725 if (err < 0) { 726 nlmsg_free(skb); 727 return ERR_PTR(err); 728 } 729 730 return skb; 731 } 732 733 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp, 734 u32 pid, int seq, u8 cmd) 735 { 736 struct sk_buff *skb; 737 int err; 738 739 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 740 if (skb == NULL) 741 return ERR_PTR(-ENOBUFS); 742 743 err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd); 744 if (err < 0) { 745 nlmsg_free(skb); 746 return ERR_PTR(err); 747 } 748 749 return skb; 750 } 751 752 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 753 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 754 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 755 .len = GENL_NAMSIZ - 1 }, 756 }; 757 758 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 759 { 760 struct sk_buff *msg; 761 struct genl_family *res = NULL; 762 int err = -EINVAL; 763 764 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 765 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 766 res = genl_family_find_byid(id); 767 err = -ENOENT; 768 } 769 770 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 771 char *name; 772 773 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 774 res = genl_family_find_byname(name); 775 err = -ENOENT; 776 } 777 778 if (res == NULL) 779 return err; 780 781 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 782 /* family doesn't exist here */ 783 return -ENOENT; 784 } 785 786 msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq, 787 CTRL_CMD_NEWFAMILY); 788 if (IS_ERR(msg)) 789 return PTR_ERR(msg); 790 791 return genlmsg_reply(msg, info); 792 } 793 794 static int genl_ctrl_event(int event, void *data) 795 { 796 struct sk_buff *msg; 797 struct genl_family *family; 798 struct genl_multicast_group *grp; 799 800 /* genl is still initialising */ 801 if (!init_net.genl_sock) 802 return 0; 803 804 switch (event) { 805 case CTRL_CMD_NEWFAMILY: 806 case CTRL_CMD_DELFAMILY: 807 family = data; 808 msg = ctrl_build_family_msg(family, 0, 0, event); 809 break; 810 case CTRL_CMD_NEWMCAST_GRP: 811 case CTRL_CMD_DELMCAST_GRP: 812 grp = data; 813 family = grp->family; 814 msg = ctrl_build_mcgrp_msg(data, 0, 0, event); 815 break; 816 default: 817 return -EINVAL; 818 } 819 820 if (IS_ERR(msg)) 821 return PTR_ERR(msg); 822 823 if (!family->netnsok) { 824 genlmsg_multicast_netns(&init_net, msg, 0, 825 GENL_ID_CTRL, GFP_KERNEL); 826 } else { 827 rcu_read_lock(); 828 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC); 829 rcu_read_unlock(); 830 } 831 832 return 0; 833 } 834 835 static struct genl_ops genl_ctrl_ops = { 836 .cmd = CTRL_CMD_GETFAMILY, 837 .doit = ctrl_getfamily, 838 .dumpit = ctrl_dumpfamily, 839 .policy = ctrl_policy, 840 }; 841 842 static struct genl_multicast_group notify_grp = { 843 .name = "notify", 844 }; 845 846 static int __net_init genl_pernet_init(struct net *net) 847 { 848 /* we'll bump the group number right afterwards */ 849 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0, 850 genl_rcv, &genl_mutex, 851 THIS_MODULE); 852 853 if (!net->genl_sock && net_eq(net, &init_net)) 854 panic("GENL: Cannot initialize generic netlink\n"); 855 856 if (!net->genl_sock) 857 return -ENOMEM; 858 859 return 0; 860 } 861 862 static void __net_exit genl_pernet_exit(struct net *net) 863 { 864 netlink_kernel_release(net->genl_sock); 865 net->genl_sock = NULL; 866 } 867 868 static struct pernet_operations genl_pernet_ops = { 869 .init = genl_pernet_init, 870 .exit = genl_pernet_exit, 871 }; 872 873 static int __init genl_init(void) 874 { 875 int i, err; 876 877 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 878 INIT_LIST_HEAD(&family_ht[i]); 879 880 err = genl_register_family(&genl_ctrl); 881 if (err < 0) 882 goto problem; 883 884 err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops); 885 if (err < 0) 886 goto problem; 887 888 netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV); 889 890 err = register_pernet_subsys(&genl_pernet_ops); 891 if (err) 892 goto problem; 893 894 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp); 895 if (err < 0) 896 goto problem; 897 898 return 0; 899 900 problem: 901 panic("GENL: Cannot register controller: %d\n", err); 902 } 903 904 subsys_initcall(genl_init); 905 906 EXPORT_SYMBOL(genl_register_ops); 907 EXPORT_SYMBOL(genl_unregister_ops); 908 EXPORT_SYMBOL(genl_register_family); 909 EXPORT_SYMBOL(genl_unregister_family); 910 911 static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group, 912 gfp_t flags) 913 { 914 struct sk_buff *tmp; 915 struct net *net, *prev = NULL; 916 int err; 917 918 for_each_net_rcu(net) { 919 if (prev) { 920 tmp = skb_clone(skb, flags); 921 if (!tmp) { 922 err = -ENOMEM; 923 goto error; 924 } 925 err = nlmsg_multicast(prev->genl_sock, tmp, 926 pid, group, flags); 927 if (err) 928 goto error; 929 } 930 931 prev = net; 932 } 933 934 return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags); 935 error: 936 kfree_skb(skb); 937 return err; 938 } 939 940 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group, 941 gfp_t flags) 942 { 943 return genlmsg_mcast(skb, pid, group, flags); 944 } 945 EXPORT_SYMBOL(genlmsg_multicast_allns); 946