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 EXPORT_SYMBOL(genl_register_ops); 307 308 /** 309 * genl_unregister_ops - unregister generic netlink operations 310 * @family: generic netlink family 311 * @ops: operations to be unregistered 312 * 313 * Unregisters the specified operations and unassigns them from the 314 * specified family. The operation blocks until the current message 315 * processing has finished and doesn't start again until the 316 * unregister process has finished. 317 * 318 * Note: It is not necessary to unregister all operations before 319 * unregistering the family, unregistering the family will cause 320 * all assigned operations to be unregistered automatically. 321 * 322 * Returns 0 on success or a negative error code. 323 */ 324 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops) 325 { 326 struct genl_ops *rc; 327 328 genl_lock(); 329 list_for_each_entry(rc, &family->ops_list, ops_list) { 330 if (rc == ops) { 331 list_del(&ops->ops_list); 332 genl_unlock(); 333 genl_ctrl_event(CTRL_CMD_DELOPS, ops); 334 return 0; 335 } 336 } 337 genl_unlock(); 338 339 return -ENOENT; 340 } 341 EXPORT_SYMBOL(genl_unregister_ops); 342 343 /** 344 * genl_register_family - register a generic netlink family 345 * @family: generic netlink family 346 * 347 * Registers the specified family after validating it first. Only one 348 * family may be registered with the same family name or identifier. 349 * The family id may equal GENL_ID_GENERATE causing an unique id to 350 * be automatically generated and assigned. 351 * 352 * Return 0 on success or a negative error code. 353 */ 354 int genl_register_family(struct genl_family *family) 355 { 356 int err = -EINVAL; 357 358 if (family->id && family->id < GENL_MIN_ID) 359 goto errout; 360 361 if (family->id > GENL_MAX_ID) 362 goto errout; 363 364 INIT_LIST_HEAD(&family->ops_list); 365 INIT_LIST_HEAD(&family->mcast_groups); 366 367 genl_lock(); 368 369 if (genl_family_find_byname(family->name)) { 370 err = -EEXIST; 371 goto errout_locked; 372 } 373 374 if (family->id == GENL_ID_GENERATE) { 375 u16 newid = genl_generate_id(); 376 377 if (!newid) { 378 err = -ENOMEM; 379 goto errout_locked; 380 } 381 382 family->id = newid; 383 } else if (genl_family_find_byid(family->id)) { 384 err = -EEXIST; 385 goto errout_locked; 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 EXPORT_SYMBOL(genl_register_family); 411 412 /** 413 * genl_register_family_with_ops - register a generic netlink family 414 * @family: generic netlink family 415 * @ops: operations to be registered 416 * @n_ops: number of elements to register 417 * 418 * Registers the specified family and operations from the specified table. 419 * Only one family may be registered with the same family name or identifier. 420 * 421 * The family id may equal GENL_ID_GENERATE causing an unique id to 422 * be automatically generated and assigned. 423 * 424 * Either a doit or dumpit callback must be specified for every registered 425 * operation or the function will fail. Only one operation structure per 426 * command identifier may be registered. 427 * 428 * See include/net/genetlink.h for more documenation on the operations 429 * structure. 430 * 431 * This is equivalent to calling genl_register_family() followed by 432 * genl_register_ops() for every operation entry in the table taking 433 * care to unregister the family on error path. 434 * 435 * Return 0 on success or a negative error code. 436 */ 437 int genl_register_family_with_ops(struct genl_family *family, 438 struct genl_ops *ops, size_t n_ops) 439 { 440 int err, i; 441 442 err = genl_register_family(family); 443 if (err) 444 return err; 445 446 for (i = 0; i < n_ops; ++i, ++ops) { 447 err = genl_register_ops(family, ops); 448 if (err) 449 goto err_out; 450 } 451 return 0; 452 err_out: 453 genl_unregister_family(family); 454 return err; 455 } 456 EXPORT_SYMBOL(genl_register_family_with_ops); 457 458 /** 459 * genl_unregister_family - unregister generic netlink family 460 * @family: generic netlink family 461 * 462 * Unregisters the specified family. 463 * 464 * Returns 0 on success or a negative error code. 465 */ 466 int genl_unregister_family(struct genl_family *family) 467 { 468 struct genl_family *rc; 469 470 genl_lock(); 471 472 genl_unregister_mc_groups(family); 473 474 list_for_each_entry(rc, genl_family_chain(family->id), family_list) { 475 if (family->id != rc->id || strcmp(rc->name, family->name)) 476 continue; 477 478 list_del(&rc->family_list); 479 INIT_LIST_HEAD(&family->ops_list); 480 genl_unlock(); 481 482 kfree(family->attrbuf); 483 genl_ctrl_event(CTRL_CMD_DELFAMILY, family); 484 return 0; 485 } 486 487 genl_unlock(); 488 489 return -ENOENT; 490 } 491 EXPORT_SYMBOL(genl_unregister_family); 492 493 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 494 { 495 struct genl_ops *ops; 496 struct genl_family *family; 497 struct net *net = sock_net(skb->sk); 498 struct genl_info info; 499 struct genlmsghdr *hdr = nlmsg_data(nlh); 500 int hdrlen, err; 501 502 family = genl_family_find_byid(nlh->nlmsg_type); 503 if (family == NULL) 504 return -ENOENT; 505 506 /* this family doesn't exist in this netns */ 507 if (!family->netnsok && !net_eq(net, &init_net)) 508 return -ENOENT; 509 510 hdrlen = GENL_HDRLEN + family->hdrsize; 511 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 512 return -EINVAL; 513 514 ops = genl_get_cmd(hdr->cmd, family); 515 if (ops == NULL) 516 return -EOPNOTSUPP; 517 518 if ((ops->flags & GENL_ADMIN_PERM) && 519 security_netlink_recv(skb, CAP_NET_ADMIN)) 520 return -EPERM; 521 522 if (nlh->nlmsg_flags & NLM_F_DUMP) { 523 if (ops->dumpit == NULL) 524 return -EOPNOTSUPP; 525 526 genl_unlock(); 527 err = netlink_dump_start(net->genl_sock, skb, nlh, 528 ops->dumpit, ops->done); 529 genl_lock(); 530 return err; 531 } 532 533 if (ops->doit == NULL) 534 return -EOPNOTSUPP; 535 536 if (family->attrbuf) { 537 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr, 538 ops->policy); 539 if (err < 0) 540 return err; 541 } 542 543 info.snd_seq = nlh->nlmsg_seq; 544 info.snd_pid = NETLINK_CB(skb).pid; 545 info.nlhdr = nlh; 546 info.genlhdr = nlmsg_data(nlh); 547 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 548 info.attrs = family->attrbuf; 549 genl_info_net_set(&info, net); 550 551 return ops->doit(skb, &info); 552 } 553 554 static void genl_rcv(struct sk_buff *skb) 555 { 556 genl_lock(); 557 netlink_rcv_skb(skb, &genl_rcv_msg); 558 genl_unlock(); 559 } 560 561 /************************************************************************** 562 * Controller 563 **************************************************************************/ 564 565 static struct genl_family genl_ctrl = { 566 .id = GENL_ID_CTRL, 567 .name = "nlctrl", 568 .version = 0x2, 569 .maxattr = CTRL_ATTR_MAX, 570 .netnsok = true, 571 }; 572 573 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq, 574 u32 flags, struct sk_buff *skb, u8 cmd) 575 { 576 void *hdr; 577 578 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); 579 if (hdr == NULL) 580 return -1; 581 582 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name); 583 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id); 584 NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version); 585 NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize); 586 NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr); 587 588 if (!list_empty(&family->ops_list)) { 589 struct nlattr *nla_ops; 590 struct genl_ops *ops; 591 int idx = 1; 592 593 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 594 if (nla_ops == NULL) 595 goto nla_put_failure; 596 597 list_for_each_entry(ops, &family->ops_list, ops_list) { 598 struct nlattr *nest; 599 600 nest = nla_nest_start(skb, idx++); 601 if (nest == NULL) 602 goto nla_put_failure; 603 604 NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd); 605 NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags); 606 607 nla_nest_end(skb, nest); 608 } 609 610 nla_nest_end(skb, nla_ops); 611 } 612 613 if (!list_empty(&family->mcast_groups)) { 614 struct genl_multicast_group *grp; 615 struct nlattr *nla_grps; 616 int idx = 1; 617 618 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 619 if (nla_grps == NULL) 620 goto nla_put_failure; 621 622 list_for_each_entry(grp, &family->mcast_groups, list) { 623 struct nlattr *nest; 624 625 nest = nla_nest_start(skb, idx++); 626 if (nest == NULL) 627 goto nla_put_failure; 628 629 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); 630 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, 631 grp->name); 632 633 nla_nest_end(skb, nest); 634 } 635 nla_nest_end(skb, nla_grps); 636 } 637 638 return genlmsg_end(skb, hdr); 639 640 nla_put_failure: 641 genlmsg_cancel(skb, hdr); 642 return -EMSGSIZE; 643 } 644 645 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid, 646 u32 seq, u32 flags, struct sk_buff *skb, 647 u8 cmd) 648 { 649 void *hdr; 650 struct nlattr *nla_grps; 651 struct nlattr *nest; 652 653 hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd); 654 if (hdr == NULL) 655 return -1; 656 657 NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name); 658 NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id); 659 660 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 661 if (nla_grps == NULL) 662 goto nla_put_failure; 663 664 nest = nla_nest_start(skb, 1); 665 if (nest == NULL) 666 goto nla_put_failure; 667 668 NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id); 669 NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME, 670 grp->name); 671 672 nla_nest_end(skb, nest); 673 nla_nest_end(skb, nla_grps); 674 675 return genlmsg_end(skb, hdr); 676 677 nla_put_failure: 678 genlmsg_cancel(skb, hdr); 679 return -EMSGSIZE; 680 } 681 682 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 683 { 684 685 int i, n = 0; 686 struct genl_family *rt; 687 struct net *net = sock_net(skb->sk); 688 int chains_to_skip = cb->args[0]; 689 int fams_to_skip = cb->args[1]; 690 691 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) { 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_with_ops(&genl_ctrl, &genl_ctrl_ops, 1); 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 static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group, 903 gfp_t flags) 904 { 905 struct sk_buff *tmp; 906 struct net *net, *prev = NULL; 907 int err; 908 909 for_each_net_rcu(net) { 910 if (prev) { 911 tmp = skb_clone(skb, flags); 912 if (!tmp) { 913 err = -ENOMEM; 914 goto error; 915 } 916 err = nlmsg_multicast(prev->genl_sock, tmp, 917 pid, group, flags); 918 if (err) 919 goto error; 920 } 921 922 prev = net; 923 } 924 925 return nlmsg_multicast(prev->genl_sock, skb, pid, group, flags); 926 error: 927 kfree_skb(skb); 928 return err; 929 } 930 931 int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid, unsigned int group, 932 gfp_t flags) 933 { 934 return genlmsg_mcast(skb, pid, group, flags); 935 } 936 EXPORT_SYMBOL(genlmsg_multicast_allns); 937