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 #ifdef CONFIG_LOCKDEP 37 int lockdep_genl_is_held(void) 38 { 39 return lockdep_is_held(&genl_mutex); 40 } 41 EXPORT_SYMBOL(lockdep_genl_is_held); 42 #endif 43 44 #define GENL_FAM_TAB_SIZE 16 45 #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) 46 47 static struct list_head family_ht[GENL_FAM_TAB_SIZE]; 48 /* 49 * Bitmap of multicast groups that are currently in use. 50 * 51 * To avoid an allocation at boot of just one unsigned long, 52 * declare it global instead. 53 * Bit 0 is marked as already used since group 0 is invalid. 54 */ 55 static unsigned long mc_group_start = 0x1; 56 static unsigned long *mc_groups = &mc_group_start; 57 static unsigned long mc_groups_longs = 1; 58 59 static int genl_ctrl_event(int event, void *data); 60 61 static inline unsigned int genl_family_hash(unsigned int id) 62 { 63 return id & GENL_FAM_TAB_MASK; 64 } 65 66 static inline struct list_head *genl_family_chain(unsigned int id) 67 { 68 return &family_ht[genl_family_hash(id)]; 69 } 70 71 static struct genl_family *genl_family_find_byid(unsigned int id) 72 { 73 struct genl_family *f; 74 75 list_for_each_entry(f, genl_family_chain(id), family_list) 76 if (f->id == id) 77 return f; 78 79 return NULL; 80 } 81 82 static struct genl_family *genl_family_find_byname(char *name) 83 { 84 struct genl_family *f; 85 int i; 86 87 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 88 list_for_each_entry(f, genl_family_chain(i), family_list) 89 if (strcmp(f->name, name) == 0) 90 return f; 91 92 return NULL; 93 } 94 95 static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) 96 { 97 struct genl_ops *ops; 98 99 list_for_each_entry(ops, &family->ops_list, ops_list) 100 if (ops->cmd == cmd) 101 return ops; 102 103 return NULL; 104 } 105 106 /* Of course we are going to have problems once we hit 107 * 2^16 alive types, but that can only happen by year 2K 108 */ 109 static u16 genl_generate_id(void) 110 { 111 static u16 id_gen_idx = GENL_MIN_ID; 112 int i; 113 114 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) { 115 if (!genl_family_find_byid(id_gen_idx)) 116 return id_gen_idx; 117 if (++id_gen_idx > GENL_MAX_ID) 118 id_gen_idx = GENL_MIN_ID; 119 } 120 121 return 0; 122 } 123 124 static struct genl_multicast_group notify_grp; 125 126 /** 127 * genl_register_mc_group - register a multicast group 128 * 129 * Registers the specified multicast group and notifies userspace 130 * about the new group. 131 * 132 * Returns 0 on success or a negative error code. 133 * 134 * @family: The generic netlink family the group shall be registered for. 135 * @grp: The group to register, must have a name. 136 */ 137 int genl_register_mc_group(struct genl_family *family, 138 struct genl_multicast_group *grp) 139 { 140 int id; 141 unsigned long *new_groups; 142 int err = 0; 143 144 BUG_ON(grp->name[0] == '\0'); 145 BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL); 146 147 genl_lock(); 148 149 /* special-case our own group */ 150 if (grp == ¬ify_grp) 151 id = GENL_ID_CTRL; 152 else 153 id = find_first_zero_bit(mc_groups, 154 mc_groups_longs * BITS_PER_LONG); 155 156 157 if (id >= mc_groups_longs * BITS_PER_LONG) { 158 size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long); 159 160 if (mc_groups == &mc_group_start) { 161 new_groups = kzalloc(nlen, GFP_KERNEL); 162 if (!new_groups) { 163 err = -ENOMEM; 164 goto out; 165 } 166 mc_groups = new_groups; 167 *mc_groups = mc_group_start; 168 } else { 169 new_groups = krealloc(mc_groups, nlen, GFP_KERNEL); 170 if (!new_groups) { 171 err = -ENOMEM; 172 goto out; 173 } 174 mc_groups = new_groups; 175 mc_groups[mc_groups_longs] = 0; 176 } 177 mc_groups_longs++; 178 } 179 180 if (family->netnsok) { 181 struct net *net; 182 183 netlink_table_grab(); 184 rcu_read_lock(); 185 for_each_net_rcu(net) { 186 err = __netlink_change_ngroups(net->genl_sock, 187 mc_groups_longs * BITS_PER_LONG); 188 if (err) { 189 /* 190 * No need to roll back, can only fail if 191 * memory allocation fails and then the 192 * number of _possible_ groups has been 193 * increased on some sockets which is ok. 194 */ 195 rcu_read_unlock(); 196 netlink_table_ungrab(); 197 goto out; 198 } 199 } 200 rcu_read_unlock(); 201 netlink_table_ungrab(); 202 } else { 203 err = netlink_change_ngroups(init_net.genl_sock, 204 mc_groups_longs * BITS_PER_LONG); 205 if (err) 206 goto out; 207 } 208 209 grp->id = id; 210 set_bit(id, mc_groups); 211 list_add_tail(&grp->list, &family->mcast_groups); 212 grp->family = family; 213 214 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp); 215 out: 216 genl_unlock(); 217 return err; 218 } 219 EXPORT_SYMBOL(genl_register_mc_group); 220 221 static void __genl_unregister_mc_group(struct genl_family *family, 222 struct genl_multicast_group *grp) 223 { 224 struct net *net; 225 BUG_ON(grp->family != family); 226 227 netlink_table_grab(); 228 rcu_read_lock(); 229 for_each_net_rcu(net) 230 __netlink_clear_multicast_users(net->genl_sock, grp->id); 231 rcu_read_unlock(); 232 netlink_table_ungrab(); 233 234 clear_bit(grp->id, mc_groups); 235 list_del(&grp->list); 236 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp); 237 grp->id = 0; 238 grp->family = NULL; 239 } 240 241 /** 242 * genl_unregister_mc_group - unregister a multicast group 243 * 244 * Unregisters the specified multicast group and notifies userspace 245 * about it. All current listeners on the group are removed. 246 * 247 * Note: It is not necessary to unregister all multicast groups before 248 * unregistering the family, unregistering the family will cause 249 * all assigned multicast groups to be unregistered automatically. 250 * 251 * @family: Generic netlink family the group belongs to. 252 * @grp: The group to unregister, must have been registered successfully 253 * previously. 254 */ 255 void genl_unregister_mc_group(struct genl_family *family, 256 struct genl_multicast_group *grp) 257 { 258 genl_lock(); 259 __genl_unregister_mc_group(family, grp); 260 genl_unlock(); 261 } 262 EXPORT_SYMBOL(genl_unregister_mc_group); 263 264 static void genl_unregister_mc_groups(struct genl_family *family) 265 { 266 struct genl_multicast_group *grp, *tmp; 267 268 list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list) 269 __genl_unregister_mc_group(family, grp); 270 } 271 272 /** 273 * genl_register_ops - register generic netlink operations 274 * @family: generic netlink family 275 * @ops: operations to be registered 276 * 277 * Registers the specified operations and assigns them to the specified 278 * family. Either a doit or dumpit callback must be specified or the 279 * operation will fail. Only one operation structure per command 280 * identifier may be registered. 281 * 282 * See include/net/genetlink.h for more documenation on the operations 283 * structure. 284 * 285 * Returns 0 on success or a negative error code. 286 */ 287 int genl_register_ops(struct genl_family *family, struct genl_ops *ops) 288 { 289 int err = -EINVAL; 290 291 if (ops->dumpit == NULL && ops->doit == NULL) 292 goto errout; 293 294 if (genl_get_cmd(ops->cmd, family)) { 295 err = -EEXIST; 296 goto errout; 297 } 298 299 if (ops->dumpit) 300 ops->flags |= GENL_CMD_CAP_DUMP; 301 if (ops->doit) 302 ops->flags |= GENL_CMD_CAP_DO; 303 if (ops->policy) 304 ops->flags |= GENL_CMD_CAP_HASPOL; 305 306 genl_lock(); 307 list_add_tail(&ops->ops_list, &family->ops_list); 308 genl_unlock(); 309 310 genl_ctrl_event(CTRL_CMD_NEWOPS, ops); 311 err = 0; 312 errout: 313 return err; 314 } 315 EXPORT_SYMBOL(genl_register_ops); 316 317 /** 318 * genl_unregister_ops - unregister generic netlink operations 319 * @family: generic netlink family 320 * @ops: operations to be unregistered 321 * 322 * Unregisters the specified operations and unassigns them from the 323 * specified family. The operation blocks until the current message 324 * processing has finished and doesn't start again until the 325 * unregister process has finished. 326 * 327 * Note: It is not necessary to unregister all operations before 328 * unregistering the family, unregistering the family will cause 329 * all assigned operations to be unregistered automatically. 330 * 331 * Returns 0 on success or a negative error code. 332 */ 333 int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops) 334 { 335 struct genl_ops *rc; 336 337 genl_lock(); 338 list_for_each_entry(rc, &family->ops_list, ops_list) { 339 if (rc == ops) { 340 list_del(&ops->ops_list); 341 genl_unlock(); 342 genl_ctrl_event(CTRL_CMD_DELOPS, ops); 343 return 0; 344 } 345 } 346 genl_unlock(); 347 348 return -ENOENT; 349 } 350 EXPORT_SYMBOL(genl_unregister_ops); 351 352 /** 353 * genl_register_family - register a generic netlink family 354 * @family: generic netlink family 355 * 356 * Registers the specified family after validating it first. Only one 357 * family may be registered with the same family name or identifier. 358 * The family id may equal GENL_ID_GENERATE causing an unique id to 359 * be automatically generated and assigned. 360 * 361 * Return 0 on success or a negative error code. 362 */ 363 int genl_register_family(struct genl_family *family) 364 { 365 int err = -EINVAL; 366 367 if (family->id && family->id < GENL_MIN_ID) 368 goto errout; 369 370 if (family->id > GENL_MAX_ID) 371 goto errout; 372 373 INIT_LIST_HEAD(&family->ops_list); 374 INIT_LIST_HEAD(&family->mcast_groups); 375 376 genl_lock(); 377 378 if (genl_family_find_byname(family->name)) { 379 err = -EEXIST; 380 goto errout_locked; 381 } 382 383 if (family->id == GENL_ID_GENERATE) { 384 u16 newid = genl_generate_id(); 385 386 if (!newid) { 387 err = -ENOMEM; 388 goto errout_locked; 389 } 390 391 family->id = newid; 392 } else if (genl_family_find_byid(family->id)) { 393 err = -EEXIST; 394 goto errout_locked; 395 } 396 397 if (family->maxattr) { 398 family->attrbuf = kmalloc((family->maxattr+1) * 399 sizeof(struct nlattr *), GFP_KERNEL); 400 if (family->attrbuf == NULL) { 401 err = -ENOMEM; 402 goto errout_locked; 403 } 404 } else 405 family->attrbuf = NULL; 406 407 list_add_tail(&family->family_list, genl_family_chain(family->id)); 408 genl_unlock(); 409 410 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family); 411 412 return 0; 413 414 errout_locked: 415 genl_unlock(); 416 errout: 417 return err; 418 } 419 EXPORT_SYMBOL(genl_register_family); 420 421 /** 422 * genl_register_family_with_ops - register a generic netlink family 423 * @family: generic netlink family 424 * @ops: operations to be registered 425 * @n_ops: number of elements to register 426 * 427 * Registers the specified family and operations from the specified table. 428 * Only one family may be registered with the same family name or identifier. 429 * 430 * The family id may equal GENL_ID_GENERATE causing an unique id to 431 * be automatically generated and assigned. 432 * 433 * Either a doit or dumpit callback must be specified for every registered 434 * operation or the function will fail. Only one operation structure per 435 * command identifier may be registered. 436 * 437 * See include/net/genetlink.h for more documenation on the operations 438 * structure. 439 * 440 * This is equivalent to calling genl_register_family() followed by 441 * genl_register_ops() for every operation entry in the table taking 442 * care to unregister the family on error path. 443 * 444 * Return 0 on success or a negative error code. 445 */ 446 int genl_register_family_with_ops(struct genl_family *family, 447 struct genl_ops *ops, size_t n_ops) 448 { 449 int err, i; 450 451 err = genl_register_family(family); 452 if (err) 453 return err; 454 455 for (i = 0; i < n_ops; ++i, ++ops) { 456 err = genl_register_ops(family, ops); 457 if (err) 458 goto err_out; 459 } 460 return 0; 461 err_out: 462 genl_unregister_family(family); 463 return err; 464 } 465 EXPORT_SYMBOL(genl_register_family_with_ops); 466 467 /** 468 * genl_unregister_family - unregister generic netlink family 469 * @family: generic netlink family 470 * 471 * Unregisters the specified family. 472 * 473 * Returns 0 on success or a negative error code. 474 */ 475 int genl_unregister_family(struct genl_family *family) 476 { 477 struct genl_family *rc; 478 479 genl_lock(); 480 481 genl_unregister_mc_groups(family); 482 483 list_for_each_entry(rc, genl_family_chain(family->id), family_list) { 484 if (family->id != rc->id || strcmp(rc->name, family->name)) 485 continue; 486 487 list_del(&rc->family_list); 488 INIT_LIST_HEAD(&family->ops_list); 489 genl_unlock(); 490 491 kfree(family->attrbuf); 492 genl_ctrl_event(CTRL_CMD_DELFAMILY, family); 493 return 0; 494 } 495 496 genl_unlock(); 497 498 return -ENOENT; 499 } 500 EXPORT_SYMBOL(genl_unregister_family); 501 502 /** 503 * genlmsg_put - Add generic netlink header to netlink message 504 * @skb: socket buffer holding the message 505 * @portid: netlink portid the message is addressed to 506 * @seq: sequence number (usually the one of the sender) 507 * @family: generic netlink family 508 * @flags: netlink message flags 509 * @cmd: generic netlink command 510 * 511 * Returns pointer to user specific header 512 */ 513 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 514 struct genl_family *family, int flags, u8 cmd) 515 { 516 struct nlmsghdr *nlh; 517 struct genlmsghdr *hdr; 518 519 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN + 520 family->hdrsize, flags); 521 if (nlh == NULL) 522 return NULL; 523 524 hdr = nlmsg_data(nlh); 525 hdr->cmd = cmd; 526 hdr->version = family->version; 527 hdr->reserved = 0; 528 529 return (char *) hdr + GENL_HDRLEN; 530 } 531 EXPORT_SYMBOL(genlmsg_put); 532 533 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 534 { 535 struct genl_ops *ops; 536 struct genl_family *family; 537 struct net *net = sock_net(skb->sk); 538 struct genl_info info; 539 struct genlmsghdr *hdr = nlmsg_data(nlh); 540 int hdrlen, err; 541 542 family = genl_family_find_byid(nlh->nlmsg_type); 543 if (family == NULL) 544 return -ENOENT; 545 546 /* this family doesn't exist in this netns */ 547 if (!family->netnsok && !net_eq(net, &init_net)) 548 return -ENOENT; 549 550 hdrlen = GENL_HDRLEN + family->hdrsize; 551 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 552 return -EINVAL; 553 554 ops = genl_get_cmd(hdr->cmd, family); 555 if (ops == NULL) 556 return -EOPNOTSUPP; 557 558 if ((ops->flags & GENL_ADMIN_PERM) && 559 !capable(CAP_NET_ADMIN)) 560 return -EPERM; 561 562 if (nlh->nlmsg_flags & NLM_F_DUMP) { 563 if (ops->dumpit == NULL) 564 return -EOPNOTSUPP; 565 566 genl_unlock(); 567 { 568 struct netlink_dump_control c = { 569 .dump = ops->dumpit, 570 .done = ops->done, 571 }; 572 err = netlink_dump_start(net->genl_sock, skb, nlh, &c); 573 } 574 genl_lock(); 575 return err; 576 } 577 578 if (ops->doit == NULL) 579 return -EOPNOTSUPP; 580 581 if (family->attrbuf) { 582 err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr, 583 ops->policy); 584 if (err < 0) 585 return err; 586 } 587 588 info.snd_seq = nlh->nlmsg_seq; 589 info.snd_portid = NETLINK_CB(skb).portid; 590 info.nlhdr = nlh; 591 info.genlhdr = nlmsg_data(nlh); 592 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 593 info.attrs = family->attrbuf; 594 genl_info_net_set(&info, net); 595 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 596 597 if (family->pre_doit) { 598 err = family->pre_doit(ops, skb, &info); 599 if (err) 600 return err; 601 } 602 603 err = ops->doit(skb, &info); 604 605 if (family->post_doit) 606 family->post_doit(ops, skb, &info); 607 608 return err; 609 } 610 611 static void genl_rcv(struct sk_buff *skb) 612 { 613 genl_lock(); 614 netlink_rcv_skb(skb, &genl_rcv_msg); 615 genl_unlock(); 616 } 617 618 /************************************************************************** 619 * Controller 620 **************************************************************************/ 621 622 static struct genl_family genl_ctrl = { 623 .id = GENL_ID_CTRL, 624 .name = "nlctrl", 625 .version = 0x2, 626 .maxattr = CTRL_ATTR_MAX, 627 .netnsok = true, 628 }; 629 630 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq, 631 u32 flags, struct sk_buff *skb, u8 cmd) 632 { 633 void *hdr; 634 635 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 636 if (hdr == NULL) 637 return -1; 638 639 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 640 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 641 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 642 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 643 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 644 goto nla_put_failure; 645 646 if (!list_empty(&family->ops_list)) { 647 struct nlattr *nla_ops; 648 struct genl_ops *ops; 649 int idx = 1; 650 651 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 652 if (nla_ops == NULL) 653 goto nla_put_failure; 654 655 list_for_each_entry(ops, &family->ops_list, ops_list) { 656 struct nlattr *nest; 657 658 nest = nla_nest_start(skb, idx++); 659 if (nest == NULL) 660 goto nla_put_failure; 661 662 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 663 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, ops->flags)) 664 goto nla_put_failure; 665 666 nla_nest_end(skb, nest); 667 } 668 669 nla_nest_end(skb, nla_ops); 670 } 671 672 if (!list_empty(&family->mcast_groups)) { 673 struct genl_multicast_group *grp; 674 struct nlattr *nla_grps; 675 int idx = 1; 676 677 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 678 if (nla_grps == NULL) 679 goto nla_put_failure; 680 681 list_for_each_entry(grp, &family->mcast_groups, list) { 682 struct nlattr *nest; 683 684 nest = nla_nest_start(skb, idx++); 685 if (nest == NULL) 686 goto nla_put_failure; 687 688 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) || 689 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 690 grp->name)) 691 goto nla_put_failure; 692 693 nla_nest_end(skb, nest); 694 } 695 nla_nest_end(skb, nla_grps); 696 } 697 698 return genlmsg_end(skb, hdr); 699 700 nla_put_failure: 701 genlmsg_cancel(skb, hdr); 702 return -EMSGSIZE; 703 } 704 705 static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid, 706 u32 seq, u32 flags, struct sk_buff *skb, 707 u8 cmd) 708 { 709 void *hdr; 710 struct nlattr *nla_grps; 711 struct nlattr *nest; 712 713 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 714 if (hdr == NULL) 715 return -1; 716 717 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) || 718 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id)) 719 goto nla_put_failure; 720 721 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 722 if (nla_grps == NULL) 723 goto nla_put_failure; 724 725 nest = nla_nest_start(skb, 1); 726 if (nest == NULL) 727 goto nla_put_failure; 728 729 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) || 730 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 731 grp->name)) 732 goto nla_put_failure; 733 734 nla_nest_end(skb, nest); 735 nla_nest_end(skb, nla_grps); 736 737 return genlmsg_end(skb, hdr); 738 739 nla_put_failure: 740 genlmsg_cancel(skb, hdr); 741 return -EMSGSIZE; 742 } 743 744 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 745 { 746 747 int i, n = 0; 748 struct genl_family *rt; 749 struct net *net = sock_net(skb->sk); 750 int chains_to_skip = cb->args[0]; 751 int fams_to_skip = cb->args[1]; 752 753 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) { 754 n = 0; 755 list_for_each_entry(rt, genl_family_chain(i), family_list) { 756 if (!rt->netnsok && !net_eq(net, &init_net)) 757 continue; 758 if (++n < fams_to_skip) 759 continue; 760 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 761 cb->nlh->nlmsg_seq, NLM_F_MULTI, 762 skb, CTRL_CMD_NEWFAMILY) < 0) 763 goto errout; 764 } 765 766 fams_to_skip = 0; 767 } 768 769 errout: 770 cb->args[0] = i; 771 cb->args[1] = n; 772 773 return skb->len; 774 } 775 776 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 777 u32 portid, int seq, u8 cmd) 778 { 779 struct sk_buff *skb; 780 int err; 781 782 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 783 if (skb == NULL) 784 return ERR_PTR(-ENOBUFS); 785 786 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 787 if (err < 0) { 788 nlmsg_free(skb); 789 return ERR_PTR(err); 790 } 791 792 return skb; 793 } 794 795 static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp, 796 u32 portid, int seq, u8 cmd) 797 { 798 struct sk_buff *skb; 799 int err; 800 801 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 802 if (skb == NULL) 803 return ERR_PTR(-ENOBUFS); 804 805 err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd); 806 if (err < 0) { 807 nlmsg_free(skb); 808 return ERR_PTR(err); 809 } 810 811 return skb; 812 } 813 814 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 815 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 816 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 817 .len = GENL_NAMSIZ - 1 }, 818 }; 819 820 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 821 { 822 struct sk_buff *msg; 823 struct genl_family *res = NULL; 824 int err = -EINVAL; 825 826 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 827 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 828 res = genl_family_find_byid(id); 829 err = -ENOENT; 830 } 831 832 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 833 char *name; 834 835 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 836 res = genl_family_find_byname(name); 837 #ifdef CONFIG_MODULES 838 if (res == NULL) { 839 genl_unlock(); 840 request_module("net-pf-%d-proto-%d-family-%s", 841 PF_NETLINK, NETLINK_GENERIC, name); 842 genl_lock(); 843 res = genl_family_find_byname(name); 844 } 845 #endif 846 err = -ENOENT; 847 } 848 849 if (res == NULL) 850 return err; 851 852 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 853 /* family doesn't exist here */ 854 return -ENOENT; 855 } 856 857 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 858 CTRL_CMD_NEWFAMILY); 859 if (IS_ERR(msg)) 860 return PTR_ERR(msg); 861 862 return genlmsg_reply(msg, info); 863 } 864 865 static int genl_ctrl_event(int event, void *data) 866 { 867 struct sk_buff *msg; 868 struct genl_family *family; 869 struct genl_multicast_group *grp; 870 871 /* genl is still initialising */ 872 if (!init_net.genl_sock) 873 return 0; 874 875 switch (event) { 876 case CTRL_CMD_NEWFAMILY: 877 case CTRL_CMD_DELFAMILY: 878 family = data; 879 msg = ctrl_build_family_msg(family, 0, 0, event); 880 break; 881 case CTRL_CMD_NEWMCAST_GRP: 882 case CTRL_CMD_DELMCAST_GRP: 883 grp = data; 884 family = grp->family; 885 msg = ctrl_build_mcgrp_msg(data, 0, 0, event); 886 break; 887 default: 888 return -EINVAL; 889 } 890 891 if (IS_ERR(msg)) 892 return PTR_ERR(msg); 893 894 if (!family->netnsok) { 895 genlmsg_multicast_netns(&init_net, msg, 0, 896 GENL_ID_CTRL, GFP_KERNEL); 897 } else { 898 rcu_read_lock(); 899 genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC); 900 rcu_read_unlock(); 901 } 902 903 return 0; 904 } 905 906 static struct genl_ops genl_ctrl_ops = { 907 .cmd = CTRL_CMD_GETFAMILY, 908 .doit = ctrl_getfamily, 909 .dumpit = ctrl_dumpfamily, 910 .policy = ctrl_policy, 911 }; 912 913 static struct genl_multicast_group notify_grp = { 914 .name = "notify", 915 }; 916 917 static int __net_init genl_pernet_init(struct net *net) 918 { 919 struct netlink_kernel_cfg cfg = { 920 .input = genl_rcv, 921 .cb_mutex = &genl_mutex, 922 .flags = NL_CFG_F_NONROOT_RECV, 923 }; 924 925 /* we'll bump the group number right afterwards */ 926 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 927 928 if (!net->genl_sock && net_eq(net, &init_net)) 929 panic("GENL: Cannot initialize generic netlink\n"); 930 931 if (!net->genl_sock) 932 return -ENOMEM; 933 934 return 0; 935 } 936 937 static void __net_exit genl_pernet_exit(struct net *net) 938 { 939 netlink_kernel_release(net->genl_sock); 940 net->genl_sock = NULL; 941 } 942 943 static struct pernet_operations genl_pernet_ops = { 944 .init = genl_pernet_init, 945 .exit = genl_pernet_exit, 946 }; 947 948 static int __init genl_init(void) 949 { 950 int i, err; 951 952 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 953 INIT_LIST_HEAD(&family_ht[i]); 954 955 err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1); 956 if (err < 0) 957 goto problem; 958 959 err = register_pernet_subsys(&genl_pernet_ops); 960 if (err) 961 goto problem; 962 963 err = genl_register_mc_group(&genl_ctrl, ¬ify_grp); 964 if (err < 0) 965 goto problem; 966 967 return 0; 968 969 problem: 970 panic("GENL: Cannot register controller: %d\n", err); 971 } 972 973 subsys_initcall(genl_init); 974 975 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 976 gfp_t flags) 977 { 978 struct sk_buff *tmp; 979 struct net *net, *prev = NULL; 980 int err; 981 982 for_each_net_rcu(net) { 983 if (prev) { 984 tmp = skb_clone(skb, flags); 985 if (!tmp) { 986 err = -ENOMEM; 987 goto error; 988 } 989 err = nlmsg_multicast(prev->genl_sock, tmp, 990 portid, group, flags); 991 if (err) 992 goto error; 993 } 994 995 prev = net; 996 } 997 998 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 999 error: 1000 kfree_skb(skb); 1001 return err; 1002 } 1003 1004 int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group, 1005 gfp_t flags) 1006 { 1007 return genlmsg_mcast(skb, portid, group, flags); 1008 } 1009 EXPORT_SYMBOL(genlmsg_multicast_allns); 1010 1011 void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group, 1012 struct nlmsghdr *nlh, gfp_t flags) 1013 { 1014 struct sock *sk = net->genl_sock; 1015 int report = 0; 1016 1017 if (nlh) 1018 report = nlmsg_report(nlh); 1019 1020 nlmsg_notify(sk, skb, portid, group, report, flags); 1021 } 1022 EXPORT_SYMBOL(genl_notify); 1023