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