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 <linux/rwsem.h> 20 #include <net/sock.h> 21 #include <net/genetlink.h> 22 23 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ 24 static DECLARE_RWSEM(cb_lock); 25 26 atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0); 27 DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq); 28 29 void genl_lock(void) 30 { 31 mutex_lock(&genl_mutex); 32 } 33 EXPORT_SYMBOL(genl_lock); 34 35 void genl_unlock(void) 36 { 37 mutex_unlock(&genl_mutex); 38 } 39 EXPORT_SYMBOL(genl_unlock); 40 41 #ifdef CONFIG_LOCKDEP 42 bool lockdep_genl_is_held(void) 43 { 44 return lockdep_is_held(&genl_mutex); 45 } 46 EXPORT_SYMBOL(lockdep_genl_is_held); 47 #endif 48 49 static void genl_lock_all(void) 50 { 51 down_write(&cb_lock); 52 genl_lock(); 53 } 54 55 static void genl_unlock_all(void) 56 { 57 genl_unlock(); 58 up_write(&cb_lock); 59 } 60 61 #define GENL_FAM_TAB_SIZE 16 62 #define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1) 63 64 static struct list_head family_ht[GENL_FAM_TAB_SIZE]; 65 /* 66 * Bitmap of multicast groups that are currently in use. 67 * 68 * To avoid an allocation at boot of just one unsigned long, 69 * declare it global instead. 70 * Bit 0 is marked as already used since group 0 is invalid. 71 * Bit 1 is marked as already used since the drop-monitor code 72 * abuses the API and thinks it can statically use group 1. 73 * That group will typically conflict with other groups that 74 * any proper users use. 75 * Bit 16 is marked as used since it's used for generic netlink 76 * and the code no longer marks pre-reserved IDs as used. 77 * Bit 17 is marked as already used since the VFS quota code 78 * also abused this API and relied on family == group ID, we 79 * cater to that by giving it a static family and group ID. 80 * Bit 18 is marked as already used since the PMCRAID driver 81 * did the same thing as the VFS quota code (maybe copied?) 82 */ 83 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | 84 BIT(GENL_ID_VFS_DQUOT) | 85 BIT(GENL_ID_PMCRAID); 86 static unsigned long *mc_groups = &mc_group_start; 87 static unsigned long mc_groups_longs = 1; 88 89 static int genl_ctrl_event(int event, struct genl_family *family, 90 const struct genl_multicast_group *grp, 91 int grp_id); 92 93 static inline unsigned int genl_family_hash(unsigned int id) 94 { 95 return id & GENL_FAM_TAB_MASK; 96 } 97 98 static inline struct list_head *genl_family_chain(unsigned int id) 99 { 100 return &family_ht[genl_family_hash(id)]; 101 } 102 103 static struct genl_family *genl_family_find_byid(unsigned int id) 104 { 105 struct genl_family *f; 106 107 list_for_each_entry(f, genl_family_chain(id), family_list) 108 if (f->id == id) 109 return f; 110 111 return NULL; 112 } 113 114 static struct genl_family *genl_family_find_byname(char *name) 115 { 116 struct genl_family *f; 117 int i; 118 119 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 120 list_for_each_entry(f, genl_family_chain(i), family_list) 121 if (strcmp(f->name, name) == 0) 122 return f; 123 124 return NULL; 125 } 126 127 static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family) 128 { 129 int i; 130 131 for (i = 0; i < family->n_ops; i++) 132 if (family->ops[i].cmd == cmd) 133 return &family->ops[i]; 134 135 return NULL; 136 } 137 138 /* Of course we are going to have problems once we hit 139 * 2^16 alive types, but that can only happen by year 2K 140 */ 141 static u16 genl_generate_id(void) 142 { 143 static u16 id_gen_idx = GENL_MIN_ID; 144 int i; 145 146 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) { 147 if (id_gen_idx != GENL_ID_VFS_DQUOT && 148 id_gen_idx != GENL_ID_PMCRAID && 149 !genl_family_find_byid(id_gen_idx)) 150 return id_gen_idx; 151 if (++id_gen_idx > GENL_MAX_ID) 152 id_gen_idx = GENL_MIN_ID; 153 } 154 155 return 0; 156 } 157 158 static int genl_allocate_reserve_groups(int n_groups, int *first_id) 159 { 160 unsigned long *new_groups; 161 int start = 0; 162 int i; 163 int id; 164 bool fits; 165 166 do { 167 if (start == 0) 168 id = find_first_zero_bit(mc_groups, 169 mc_groups_longs * 170 BITS_PER_LONG); 171 else 172 id = find_next_zero_bit(mc_groups, 173 mc_groups_longs * BITS_PER_LONG, 174 start); 175 176 fits = true; 177 for (i = id; 178 i < min_t(int, id + n_groups, 179 mc_groups_longs * BITS_PER_LONG); 180 i++) { 181 if (test_bit(i, mc_groups)) { 182 start = i; 183 fits = false; 184 break; 185 } 186 } 187 188 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) { 189 unsigned long new_longs = mc_groups_longs + 190 BITS_TO_LONGS(n_groups); 191 size_t nlen = new_longs * sizeof(unsigned long); 192 193 if (mc_groups == &mc_group_start) { 194 new_groups = kzalloc(nlen, GFP_KERNEL); 195 if (!new_groups) 196 return -ENOMEM; 197 mc_groups = new_groups; 198 *mc_groups = mc_group_start; 199 } else { 200 new_groups = krealloc(mc_groups, nlen, 201 GFP_KERNEL); 202 if (!new_groups) 203 return -ENOMEM; 204 mc_groups = new_groups; 205 for (i = 0; i < BITS_TO_LONGS(n_groups); i++) 206 mc_groups[mc_groups_longs + i] = 0; 207 } 208 mc_groups_longs = new_longs; 209 } 210 } while (!fits); 211 212 for (i = id; i < id + n_groups; i++) 213 set_bit(i, mc_groups); 214 *first_id = id; 215 return 0; 216 } 217 218 static struct genl_family genl_ctrl; 219 220 static int genl_validate_assign_mc_groups(struct genl_family *family) 221 { 222 int first_id; 223 int n_groups = family->n_mcgrps; 224 int err = 0, i; 225 bool groups_allocated = false; 226 227 if (!n_groups) 228 return 0; 229 230 for (i = 0; i < n_groups; i++) { 231 const struct genl_multicast_group *grp = &family->mcgrps[i]; 232 233 if (WARN_ON(grp->name[0] == '\0')) 234 return -EINVAL; 235 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL)) 236 return -EINVAL; 237 } 238 239 /* special-case our own group and hacks */ 240 if (family == &genl_ctrl) { 241 first_id = GENL_ID_CTRL; 242 BUG_ON(n_groups != 1); 243 } else if (strcmp(family->name, "NET_DM") == 0) { 244 first_id = 1; 245 BUG_ON(n_groups != 1); 246 } else if (family->id == GENL_ID_VFS_DQUOT) { 247 first_id = GENL_ID_VFS_DQUOT; 248 BUG_ON(n_groups != 1); 249 } else if (family->id == GENL_ID_PMCRAID) { 250 first_id = GENL_ID_PMCRAID; 251 BUG_ON(n_groups != 1); 252 } else { 253 groups_allocated = true; 254 err = genl_allocate_reserve_groups(n_groups, &first_id); 255 if (err) 256 return err; 257 } 258 259 family->mcgrp_offset = first_id; 260 261 /* if still initializing, can't and don't need to to realloc bitmaps */ 262 if (!init_net.genl_sock) 263 return 0; 264 265 if (family->netnsok) { 266 struct net *net; 267 268 netlink_table_grab(); 269 rcu_read_lock(); 270 for_each_net_rcu(net) { 271 err = __netlink_change_ngroups(net->genl_sock, 272 mc_groups_longs * BITS_PER_LONG); 273 if (err) { 274 /* 275 * No need to roll back, can only fail if 276 * memory allocation fails and then the 277 * number of _possible_ groups has been 278 * increased on some sockets which is ok. 279 */ 280 break; 281 } 282 } 283 rcu_read_unlock(); 284 netlink_table_ungrab(); 285 } else { 286 err = netlink_change_ngroups(init_net.genl_sock, 287 mc_groups_longs * BITS_PER_LONG); 288 } 289 290 if (groups_allocated && err) { 291 for (i = 0; i < family->n_mcgrps; i++) 292 clear_bit(family->mcgrp_offset + i, mc_groups); 293 } 294 295 return err; 296 } 297 298 static void genl_unregister_mc_groups(struct genl_family *family) 299 { 300 struct net *net; 301 int i; 302 303 netlink_table_grab(); 304 rcu_read_lock(); 305 for_each_net_rcu(net) { 306 for (i = 0; i < family->n_mcgrps; i++) 307 __netlink_clear_multicast_users( 308 net->genl_sock, family->mcgrp_offset + i); 309 } 310 rcu_read_unlock(); 311 netlink_table_ungrab(); 312 313 for (i = 0; i < family->n_mcgrps; i++) { 314 int grp_id = family->mcgrp_offset + i; 315 316 if (grp_id != 1) 317 clear_bit(grp_id, mc_groups); 318 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, 319 &family->mcgrps[i], grp_id); 320 } 321 } 322 323 static int genl_validate_ops(const struct genl_family *family) 324 { 325 const struct genl_ops *ops = family->ops; 326 unsigned int n_ops = family->n_ops; 327 int i, j; 328 329 if (WARN_ON(n_ops && !ops)) 330 return -EINVAL; 331 332 if (!n_ops) 333 return 0; 334 335 for (i = 0; i < n_ops; i++) { 336 if (ops[i].dumpit == NULL && ops[i].doit == NULL) 337 return -EINVAL; 338 for (j = i + 1; j < n_ops; j++) 339 if (ops[i].cmd == ops[j].cmd) 340 return -EINVAL; 341 } 342 343 return 0; 344 } 345 346 /** 347 * __genl_register_family - register a generic netlink family 348 * @family: generic netlink family 349 * 350 * Registers the specified family after validating it first. Only one 351 * family may be registered with the same family name or identifier. 352 * The family id may equal GENL_ID_GENERATE causing an unique id to 353 * be automatically generated and assigned. 354 * 355 * The family's ops array must already be assigned, you can use the 356 * genl_register_family_with_ops() helper function. 357 * 358 * Return 0 on success or a negative error code. 359 */ 360 int __genl_register_family(struct genl_family *family) 361 { 362 int err = -EINVAL, i; 363 364 if (family->id && family->id < GENL_MIN_ID) 365 goto errout; 366 367 if (family->id > GENL_MAX_ID) 368 goto errout; 369 370 err = genl_validate_ops(family); 371 if (err) 372 return err; 373 374 genl_lock_all(); 375 376 if (genl_family_find_byname(family->name)) { 377 err = -EEXIST; 378 goto errout_locked; 379 } 380 381 if (family->id == GENL_ID_GENERATE) { 382 u16 newid = genl_generate_id(); 383 384 if (!newid) { 385 err = -ENOMEM; 386 goto errout_locked; 387 } 388 389 family->id = newid; 390 } else if (genl_family_find_byid(family->id)) { 391 err = -EEXIST; 392 goto errout_locked; 393 } 394 395 if (family->maxattr && !family->parallel_ops) { 396 family->attrbuf = kmalloc((family->maxattr+1) * 397 sizeof(struct nlattr *), GFP_KERNEL); 398 if (family->attrbuf == NULL) { 399 err = -ENOMEM; 400 goto errout_locked; 401 } 402 } else 403 family->attrbuf = NULL; 404 405 err = genl_validate_assign_mc_groups(family); 406 if (err) 407 goto errout_locked; 408 409 list_add_tail(&family->family_list, genl_family_chain(family->id)); 410 genl_unlock_all(); 411 412 /* send all events */ 413 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0); 414 for (i = 0; i < family->n_mcgrps; i++) 415 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, 416 &family->mcgrps[i], family->mcgrp_offset + i); 417 418 return 0; 419 420 errout_locked: 421 genl_unlock_all(); 422 errout: 423 return err; 424 } 425 EXPORT_SYMBOL(__genl_register_family); 426 427 /** 428 * genl_unregister_family - unregister generic netlink family 429 * @family: generic netlink family 430 * 431 * Unregisters the specified family. 432 * 433 * Returns 0 on success or a negative error code. 434 */ 435 int genl_unregister_family(struct genl_family *family) 436 { 437 struct genl_family *rc; 438 439 genl_lock_all(); 440 441 list_for_each_entry(rc, genl_family_chain(family->id), family_list) { 442 if (family->id != rc->id || strcmp(rc->name, family->name)) 443 continue; 444 445 genl_unregister_mc_groups(family); 446 447 list_del(&rc->family_list); 448 family->n_ops = 0; 449 up_write(&cb_lock); 450 wait_event(genl_sk_destructing_waitq, 451 atomic_read(&genl_sk_destructing_cnt) == 0); 452 genl_unlock(); 453 454 kfree(family->attrbuf); 455 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); 456 return 0; 457 } 458 459 genl_unlock_all(); 460 461 return -ENOENT; 462 } 463 EXPORT_SYMBOL(genl_unregister_family); 464 465 /** 466 * genlmsg_new_unicast - Allocate generic netlink message for unicast 467 * @payload: size of the message payload 468 * @info: information on destination 469 * @flags: the type of memory to allocate 470 * 471 * Allocates a new sk_buff large enough to cover the specified payload 472 * plus required Netlink headers. Will check receiving socket for 473 * memory mapped i/o capability and use it if enabled. Will fall back 474 * to non-mapped skb if message size exceeds the frame size of the ring. 475 */ 476 struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info, 477 gfp_t flags) 478 { 479 size_t len = nlmsg_total_size(genlmsg_total_size(payload)); 480 481 return netlink_alloc_skb(info->dst_sk, len, info->snd_portid, flags); 482 } 483 EXPORT_SYMBOL_GPL(genlmsg_new_unicast); 484 485 /** 486 * genlmsg_put - Add generic netlink header to netlink message 487 * @skb: socket buffer holding the message 488 * @portid: netlink portid the message is addressed to 489 * @seq: sequence number (usually the one of the sender) 490 * @family: generic netlink family 491 * @flags: netlink message flags 492 * @cmd: generic netlink command 493 * 494 * Returns pointer to user specific header 495 */ 496 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 497 struct genl_family *family, int flags, u8 cmd) 498 { 499 struct nlmsghdr *nlh; 500 struct genlmsghdr *hdr; 501 502 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN + 503 family->hdrsize, flags); 504 if (nlh == NULL) 505 return NULL; 506 507 hdr = nlmsg_data(nlh); 508 hdr->cmd = cmd; 509 hdr->version = family->version; 510 hdr->reserved = 0; 511 512 return (char *) hdr + GENL_HDRLEN; 513 } 514 EXPORT_SYMBOL(genlmsg_put); 515 516 static int genl_lock_start(struct netlink_callback *cb) 517 { 518 /* our ops are always const - netlink API doesn't propagate that */ 519 const struct genl_ops *ops = cb->data; 520 int rc = 0; 521 522 if (ops->start) { 523 genl_lock(); 524 rc = ops->start(cb); 525 genl_unlock(); 526 } 527 return rc; 528 } 529 530 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 531 { 532 /* our ops are always const - netlink API doesn't propagate that */ 533 const struct genl_ops *ops = cb->data; 534 int rc; 535 536 genl_lock(); 537 rc = ops->dumpit(skb, cb); 538 genl_unlock(); 539 return rc; 540 } 541 542 static int genl_lock_done(struct netlink_callback *cb) 543 { 544 /* our ops are always const - netlink API doesn't propagate that */ 545 const struct genl_ops *ops = cb->data; 546 int rc = 0; 547 548 if (ops->done) { 549 genl_lock(); 550 rc = ops->done(cb); 551 genl_unlock(); 552 } 553 return rc; 554 } 555 556 static int genl_family_rcv_msg(struct genl_family *family, 557 struct sk_buff *skb, 558 struct nlmsghdr *nlh) 559 { 560 const struct genl_ops *ops; 561 struct net *net = sock_net(skb->sk); 562 struct genl_info info; 563 struct genlmsghdr *hdr = nlmsg_data(nlh); 564 struct nlattr **attrbuf; 565 int hdrlen, err; 566 567 /* this family doesn't exist in this netns */ 568 if (!family->netnsok && !net_eq(net, &init_net)) 569 return -ENOENT; 570 571 hdrlen = GENL_HDRLEN + family->hdrsize; 572 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 573 return -EINVAL; 574 575 ops = genl_get_cmd(hdr->cmd, family); 576 if (ops == NULL) 577 return -EOPNOTSUPP; 578 579 if ((ops->flags & GENL_ADMIN_PERM) && 580 !netlink_capable(skb, CAP_NET_ADMIN)) 581 return -EPERM; 582 583 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) { 584 int rc; 585 586 if (ops->dumpit == NULL) 587 return -EOPNOTSUPP; 588 589 if (!family->parallel_ops) { 590 struct netlink_dump_control c = { 591 .module = family->module, 592 /* we have const, but the netlink API doesn't */ 593 .data = (void *)ops, 594 .start = genl_lock_start, 595 .dump = genl_lock_dumpit, 596 .done = genl_lock_done, 597 }; 598 599 genl_unlock(); 600 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 601 genl_lock(); 602 603 } else { 604 struct netlink_dump_control c = { 605 .module = family->module, 606 .start = ops->start, 607 .dump = ops->dumpit, 608 .done = ops->done, 609 }; 610 611 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 612 } 613 614 return rc; 615 } 616 617 if (ops->doit == NULL) 618 return -EOPNOTSUPP; 619 620 if (family->maxattr && family->parallel_ops) { 621 attrbuf = kmalloc((family->maxattr+1) * 622 sizeof(struct nlattr *), GFP_KERNEL); 623 if (attrbuf == NULL) 624 return -ENOMEM; 625 } else 626 attrbuf = family->attrbuf; 627 628 if (attrbuf) { 629 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, 630 ops->policy); 631 if (err < 0) 632 goto out; 633 } 634 635 info.snd_seq = nlh->nlmsg_seq; 636 info.snd_portid = NETLINK_CB(skb).portid; 637 info.nlhdr = nlh; 638 info.genlhdr = nlmsg_data(nlh); 639 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 640 info.attrs = attrbuf; 641 info.dst_sk = skb->sk; 642 genl_info_net_set(&info, net); 643 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 644 645 if (family->pre_doit) { 646 err = family->pre_doit(ops, skb, &info); 647 if (err) 648 goto out; 649 } 650 651 err = ops->doit(skb, &info); 652 653 if (family->post_doit) 654 family->post_doit(ops, skb, &info); 655 656 out: 657 if (family->parallel_ops) 658 kfree(attrbuf); 659 660 return err; 661 } 662 663 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 664 { 665 struct genl_family *family; 666 int err; 667 668 family = genl_family_find_byid(nlh->nlmsg_type); 669 if (family == NULL) 670 return -ENOENT; 671 672 if (!family->parallel_ops) 673 genl_lock(); 674 675 err = genl_family_rcv_msg(family, skb, nlh); 676 677 if (!family->parallel_ops) 678 genl_unlock(); 679 680 return err; 681 } 682 683 static void genl_rcv(struct sk_buff *skb) 684 { 685 down_read(&cb_lock); 686 netlink_rcv_skb(skb, &genl_rcv_msg); 687 up_read(&cb_lock); 688 } 689 690 /************************************************************************** 691 * Controller 692 **************************************************************************/ 693 694 static struct genl_family genl_ctrl = { 695 .id = GENL_ID_CTRL, 696 .name = "nlctrl", 697 .version = 0x2, 698 .maxattr = CTRL_ATTR_MAX, 699 .netnsok = true, 700 }; 701 702 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq, 703 u32 flags, struct sk_buff *skb, u8 cmd) 704 { 705 void *hdr; 706 707 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 708 if (hdr == NULL) 709 return -1; 710 711 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 712 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 713 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 714 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 715 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 716 goto nla_put_failure; 717 718 if (family->n_ops) { 719 struct nlattr *nla_ops; 720 int i; 721 722 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 723 if (nla_ops == NULL) 724 goto nla_put_failure; 725 726 for (i = 0; i < family->n_ops; i++) { 727 struct nlattr *nest; 728 const struct genl_ops *ops = &family->ops[i]; 729 u32 op_flags = ops->flags; 730 731 if (ops->dumpit) 732 op_flags |= GENL_CMD_CAP_DUMP; 733 if (ops->doit) 734 op_flags |= GENL_CMD_CAP_DO; 735 if (ops->policy) 736 op_flags |= GENL_CMD_CAP_HASPOL; 737 738 nest = nla_nest_start(skb, i + 1); 739 if (nest == NULL) 740 goto nla_put_failure; 741 742 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 743 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 744 goto nla_put_failure; 745 746 nla_nest_end(skb, nest); 747 } 748 749 nla_nest_end(skb, nla_ops); 750 } 751 752 if (family->n_mcgrps) { 753 struct nlattr *nla_grps; 754 int i; 755 756 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 757 if (nla_grps == NULL) 758 goto nla_put_failure; 759 760 for (i = 0; i < family->n_mcgrps; i++) { 761 struct nlattr *nest; 762 const struct genl_multicast_group *grp; 763 764 grp = &family->mcgrps[i]; 765 766 nest = nla_nest_start(skb, i + 1); 767 if (nest == NULL) 768 goto nla_put_failure; 769 770 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 771 family->mcgrp_offset + i) || 772 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 773 grp->name)) 774 goto nla_put_failure; 775 776 nla_nest_end(skb, nest); 777 } 778 nla_nest_end(skb, nla_grps); 779 } 780 781 genlmsg_end(skb, hdr); 782 return 0; 783 784 nla_put_failure: 785 genlmsg_cancel(skb, hdr); 786 return -EMSGSIZE; 787 } 788 789 static int ctrl_fill_mcgrp_info(struct genl_family *family, 790 const struct genl_multicast_group *grp, 791 int grp_id, u32 portid, u32 seq, u32 flags, 792 struct sk_buff *skb, u8 cmd) 793 { 794 void *hdr; 795 struct nlattr *nla_grps; 796 struct nlattr *nest; 797 798 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 799 if (hdr == NULL) 800 return -1; 801 802 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 803 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 804 goto nla_put_failure; 805 806 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 807 if (nla_grps == NULL) 808 goto nla_put_failure; 809 810 nest = nla_nest_start(skb, 1); 811 if (nest == NULL) 812 goto nla_put_failure; 813 814 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 815 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 816 grp->name)) 817 goto nla_put_failure; 818 819 nla_nest_end(skb, nest); 820 nla_nest_end(skb, nla_grps); 821 822 genlmsg_end(skb, hdr); 823 return 0; 824 825 nla_put_failure: 826 genlmsg_cancel(skb, hdr); 827 return -EMSGSIZE; 828 } 829 830 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 831 { 832 833 int i, n = 0; 834 struct genl_family *rt; 835 struct net *net = sock_net(skb->sk); 836 int chains_to_skip = cb->args[0]; 837 int fams_to_skip = cb->args[1]; 838 839 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) { 840 n = 0; 841 list_for_each_entry(rt, genl_family_chain(i), family_list) { 842 if (!rt->netnsok && !net_eq(net, &init_net)) 843 continue; 844 if (++n < fams_to_skip) 845 continue; 846 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 847 cb->nlh->nlmsg_seq, NLM_F_MULTI, 848 skb, CTRL_CMD_NEWFAMILY) < 0) 849 goto errout; 850 } 851 852 fams_to_skip = 0; 853 } 854 855 errout: 856 cb->args[0] = i; 857 cb->args[1] = n; 858 859 return skb->len; 860 } 861 862 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 863 u32 portid, int seq, u8 cmd) 864 { 865 struct sk_buff *skb; 866 int err; 867 868 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 869 if (skb == NULL) 870 return ERR_PTR(-ENOBUFS); 871 872 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 873 if (err < 0) { 874 nlmsg_free(skb); 875 return ERR_PTR(err); 876 } 877 878 return skb; 879 } 880 881 static struct sk_buff * 882 ctrl_build_mcgrp_msg(struct genl_family *family, 883 const struct genl_multicast_group *grp, 884 int grp_id, u32 portid, int seq, u8 cmd) 885 { 886 struct sk_buff *skb; 887 int err; 888 889 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 890 if (skb == NULL) 891 return ERR_PTR(-ENOBUFS); 892 893 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 894 seq, 0, skb, cmd); 895 if (err < 0) { 896 nlmsg_free(skb); 897 return ERR_PTR(err); 898 } 899 900 return skb; 901 } 902 903 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 904 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 905 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 906 .len = GENL_NAMSIZ - 1 }, 907 }; 908 909 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 910 { 911 struct sk_buff *msg; 912 struct genl_family *res = NULL; 913 int err = -EINVAL; 914 915 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 916 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 917 res = genl_family_find_byid(id); 918 err = -ENOENT; 919 } 920 921 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 922 char *name; 923 924 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 925 res = genl_family_find_byname(name); 926 #ifdef CONFIG_MODULES 927 if (res == NULL) { 928 genl_unlock(); 929 up_read(&cb_lock); 930 request_module("net-pf-%d-proto-%d-family-%s", 931 PF_NETLINK, NETLINK_GENERIC, name); 932 down_read(&cb_lock); 933 genl_lock(); 934 res = genl_family_find_byname(name); 935 } 936 #endif 937 err = -ENOENT; 938 } 939 940 if (res == NULL) 941 return err; 942 943 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 944 /* family doesn't exist here */ 945 return -ENOENT; 946 } 947 948 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 949 CTRL_CMD_NEWFAMILY); 950 if (IS_ERR(msg)) 951 return PTR_ERR(msg); 952 953 return genlmsg_reply(msg, info); 954 } 955 956 static int genl_ctrl_event(int event, struct genl_family *family, 957 const struct genl_multicast_group *grp, 958 int grp_id) 959 { 960 struct sk_buff *msg; 961 962 /* genl is still initialising */ 963 if (!init_net.genl_sock) 964 return 0; 965 966 switch (event) { 967 case CTRL_CMD_NEWFAMILY: 968 case CTRL_CMD_DELFAMILY: 969 WARN_ON(grp); 970 msg = ctrl_build_family_msg(family, 0, 0, event); 971 break; 972 case CTRL_CMD_NEWMCAST_GRP: 973 case CTRL_CMD_DELMCAST_GRP: 974 BUG_ON(!grp); 975 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 976 break; 977 default: 978 return -EINVAL; 979 } 980 981 if (IS_ERR(msg)) 982 return PTR_ERR(msg); 983 984 if (!family->netnsok) { 985 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 986 0, GFP_KERNEL); 987 } else { 988 rcu_read_lock(); 989 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 990 0, GFP_ATOMIC); 991 rcu_read_unlock(); 992 } 993 994 return 0; 995 } 996 997 static struct genl_ops genl_ctrl_ops[] = { 998 { 999 .cmd = CTRL_CMD_GETFAMILY, 1000 .doit = ctrl_getfamily, 1001 .dumpit = ctrl_dumpfamily, 1002 .policy = ctrl_policy, 1003 }, 1004 }; 1005 1006 static struct genl_multicast_group genl_ctrl_groups[] = { 1007 { .name = "notify", }, 1008 }; 1009 1010 static int genl_bind(struct net *net, int group) 1011 { 1012 int i, err = -ENOENT; 1013 1014 down_read(&cb_lock); 1015 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 1016 struct genl_family *f; 1017 1018 list_for_each_entry(f, genl_family_chain(i), family_list) { 1019 if (group >= f->mcgrp_offset && 1020 group < f->mcgrp_offset + f->n_mcgrps) { 1021 int fam_grp = group - f->mcgrp_offset; 1022 1023 if (!f->netnsok && net != &init_net) 1024 err = -ENOENT; 1025 else if (f->mcast_bind) 1026 err = f->mcast_bind(net, fam_grp); 1027 else 1028 err = 0; 1029 break; 1030 } 1031 } 1032 } 1033 up_read(&cb_lock); 1034 1035 return err; 1036 } 1037 1038 static void genl_unbind(struct net *net, int group) 1039 { 1040 int i; 1041 1042 down_read(&cb_lock); 1043 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 1044 struct genl_family *f; 1045 1046 list_for_each_entry(f, genl_family_chain(i), family_list) { 1047 if (group >= f->mcgrp_offset && 1048 group < f->mcgrp_offset + f->n_mcgrps) { 1049 int fam_grp = group - f->mcgrp_offset; 1050 1051 if (f->mcast_unbind) 1052 f->mcast_unbind(net, fam_grp); 1053 break; 1054 } 1055 } 1056 } 1057 up_read(&cb_lock); 1058 } 1059 1060 static int __net_init genl_pernet_init(struct net *net) 1061 { 1062 struct netlink_kernel_cfg cfg = { 1063 .input = genl_rcv, 1064 .flags = NL_CFG_F_NONROOT_RECV, 1065 .bind = genl_bind, 1066 .unbind = genl_unbind, 1067 }; 1068 1069 /* we'll bump the group number right afterwards */ 1070 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1071 1072 if (!net->genl_sock && net_eq(net, &init_net)) 1073 panic("GENL: Cannot initialize generic netlink\n"); 1074 1075 if (!net->genl_sock) 1076 return -ENOMEM; 1077 1078 return 0; 1079 } 1080 1081 static void __net_exit genl_pernet_exit(struct net *net) 1082 { 1083 netlink_kernel_release(net->genl_sock); 1084 net->genl_sock = NULL; 1085 } 1086 1087 static struct pernet_operations genl_pernet_ops = { 1088 .init = genl_pernet_init, 1089 .exit = genl_pernet_exit, 1090 }; 1091 1092 static int __init genl_init(void) 1093 { 1094 int i, err; 1095 1096 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 1097 INIT_LIST_HEAD(&family_ht[i]); 1098 1099 err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops, 1100 genl_ctrl_groups); 1101 if (err < 0) 1102 goto problem; 1103 1104 err = register_pernet_subsys(&genl_pernet_ops); 1105 if (err) 1106 goto problem; 1107 1108 return 0; 1109 1110 problem: 1111 panic("GENL: Cannot register controller: %d\n", err); 1112 } 1113 1114 subsys_initcall(genl_init); 1115 1116 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1117 gfp_t flags) 1118 { 1119 struct sk_buff *tmp; 1120 struct net *net, *prev = NULL; 1121 int err; 1122 1123 for_each_net_rcu(net) { 1124 if (prev) { 1125 tmp = skb_clone(skb, flags); 1126 if (!tmp) { 1127 err = -ENOMEM; 1128 goto error; 1129 } 1130 err = nlmsg_multicast(prev->genl_sock, tmp, 1131 portid, group, flags); 1132 if (err) 1133 goto error; 1134 } 1135 1136 prev = net; 1137 } 1138 1139 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1140 error: 1141 kfree_skb(skb); 1142 return err; 1143 } 1144 1145 int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb, 1146 u32 portid, unsigned int group, gfp_t flags) 1147 { 1148 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1149 return -EINVAL; 1150 group = family->mcgrp_offset + group; 1151 return genlmsg_mcast(skb, portid, group, flags); 1152 } 1153 EXPORT_SYMBOL(genlmsg_multicast_allns); 1154 1155 void genl_notify(struct genl_family *family, struct sk_buff *skb, 1156 struct genl_info *info, u32 group, gfp_t flags) 1157 { 1158 struct net *net = genl_info_net(info); 1159 struct sock *sk = net->genl_sock; 1160 int report = 0; 1161 1162 if (info->nlhdr) 1163 report = nlmsg_report(info->nlhdr); 1164 1165 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1166 return; 1167 group = family->mcgrp_offset + group; 1168 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); 1169 } 1170 EXPORT_SYMBOL(genl_notify); 1171