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 int 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 >= 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_dumpit(struct sk_buff *skb, 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; 521 522 genl_lock(); 523 rc = ops->dumpit(skb, cb); 524 genl_unlock(); 525 return rc; 526 } 527 528 static int genl_lock_done(struct netlink_callback *cb) 529 { 530 /* our ops are always const - netlink API doesn't propagate that */ 531 const struct genl_ops *ops = cb->data; 532 int rc = 0; 533 534 if (ops->done) { 535 genl_lock(); 536 rc = ops->done(cb); 537 genl_unlock(); 538 } 539 return rc; 540 } 541 542 static int genl_family_rcv_msg(struct genl_family *family, 543 struct sk_buff *skb, 544 struct nlmsghdr *nlh) 545 { 546 const struct genl_ops *ops; 547 struct net *net = sock_net(skb->sk); 548 struct genl_info info; 549 struct genlmsghdr *hdr = nlmsg_data(nlh); 550 struct nlattr **attrbuf; 551 int hdrlen, err; 552 553 /* this family doesn't exist in this netns */ 554 if (!family->netnsok && !net_eq(net, &init_net)) 555 return -ENOENT; 556 557 hdrlen = GENL_HDRLEN + family->hdrsize; 558 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 559 return -EINVAL; 560 561 ops = genl_get_cmd(hdr->cmd, family); 562 if (ops == NULL) 563 return -EOPNOTSUPP; 564 565 if ((ops->flags & GENL_ADMIN_PERM) && 566 !netlink_capable(skb, CAP_NET_ADMIN)) 567 return -EPERM; 568 569 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) { 570 int rc; 571 572 if (ops->dumpit == NULL) 573 return -EOPNOTSUPP; 574 575 if (!family->parallel_ops) { 576 struct netlink_dump_control c = { 577 .module = family->module, 578 /* we have const, but the netlink API doesn't */ 579 .data = (void *)ops, 580 .dump = genl_lock_dumpit, 581 .done = genl_lock_done, 582 }; 583 584 genl_unlock(); 585 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 586 genl_lock(); 587 588 } else { 589 struct netlink_dump_control c = { 590 .module = family->module, 591 .dump = ops->dumpit, 592 .done = ops->done, 593 }; 594 595 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 596 } 597 598 return rc; 599 } 600 601 if (ops->doit == NULL) 602 return -EOPNOTSUPP; 603 604 if (family->maxattr && family->parallel_ops) { 605 attrbuf = kmalloc((family->maxattr+1) * 606 sizeof(struct nlattr *), GFP_KERNEL); 607 if (attrbuf == NULL) 608 return -ENOMEM; 609 } else 610 attrbuf = family->attrbuf; 611 612 if (attrbuf) { 613 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, 614 ops->policy); 615 if (err < 0) 616 goto out; 617 } 618 619 info.snd_seq = nlh->nlmsg_seq; 620 info.snd_portid = NETLINK_CB(skb).portid; 621 info.nlhdr = nlh; 622 info.genlhdr = nlmsg_data(nlh); 623 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 624 info.attrs = attrbuf; 625 info.dst_sk = skb->sk; 626 genl_info_net_set(&info, net); 627 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 628 629 if (family->pre_doit) { 630 err = family->pre_doit(ops, skb, &info); 631 if (err) 632 goto out; 633 } 634 635 err = ops->doit(skb, &info); 636 637 if (family->post_doit) 638 family->post_doit(ops, skb, &info); 639 640 out: 641 if (family->parallel_ops) 642 kfree(attrbuf); 643 644 return err; 645 } 646 647 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 648 { 649 struct genl_family *family; 650 int err; 651 652 family = genl_family_find_byid(nlh->nlmsg_type); 653 if (family == NULL) 654 return -ENOENT; 655 656 if (!family->parallel_ops) 657 genl_lock(); 658 659 err = genl_family_rcv_msg(family, skb, nlh); 660 661 if (!family->parallel_ops) 662 genl_unlock(); 663 664 return err; 665 } 666 667 static void genl_rcv(struct sk_buff *skb) 668 { 669 down_read(&cb_lock); 670 netlink_rcv_skb(skb, &genl_rcv_msg); 671 up_read(&cb_lock); 672 } 673 674 /************************************************************************** 675 * Controller 676 **************************************************************************/ 677 678 static struct genl_family genl_ctrl = { 679 .id = GENL_ID_CTRL, 680 .name = "nlctrl", 681 .version = 0x2, 682 .maxattr = CTRL_ATTR_MAX, 683 .netnsok = true, 684 }; 685 686 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq, 687 u32 flags, struct sk_buff *skb, u8 cmd) 688 { 689 void *hdr; 690 691 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 692 if (hdr == NULL) 693 return -1; 694 695 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 696 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 697 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 698 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 699 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 700 goto nla_put_failure; 701 702 if (family->n_ops) { 703 struct nlattr *nla_ops; 704 int i; 705 706 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 707 if (nla_ops == NULL) 708 goto nla_put_failure; 709 710 for (i = 0; i < family->n_ops; i++) { 711 struct nlattr *nest; 712 const struct genl_ops *ops = &family->ops[i]; 713 u32 op_flags = ops->flags; 714 715 if (ops->dumpit) 716 op_flags |= GENL_CMD_CAP_DUMP; 717 if (ops->doit) 718 op_flags |= GENL_CMD_CAP_DO; 719 if (ops->policy) 720 op_flags |= GENL_CMD_CAP_HASPOL; 721 722 nest = nla_nest_start(skb, i + 1); 723 if (nest == NULL) 724 goto nla_put_failure; 725 726 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 727 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 728 goto nla_put_failure; 729 730 nla_nest_end(skb, nest); 731 } 732 733 nla_nest_end(skb, nla_ops); 734 } 735 736 if (family->n_mcgrps) { 737 struct nlattr *nla_grps; 738 int i; 739 740 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 741 if (nla_grps == NULL) 742 goto nla_put_failure; 743 744 for (i = 0; i < family->n_mcgrps; i++) { 745 struct nlattr *nest; 746 const struct genl_multicast_group *grp; 747 748 grp = &family->mcgrps[i]; 749 750 nest = nla_nest_start(skb, i + 1); 751 if (nest == NULL) 752 goto nla_put_failure; 753 754 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 755 family->mcgrp_offset + i) || 756 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 757 grp->name)) 758 goto nla_put_failure; 759 760 nla_nest_end(skb, nest); 761 } 762 nla_nest_end(skb, nla_grps); 763 } 764 765 genlmsg_end(skb, hdr); 766 return 0; 767 768 nla_put_failure: 769 genlmsg_cancel(skb, hdr); 770 return -EMSGSIZE; 771 } 772 773 static int ctrl_fill_mcgrp_info(struct genl_family *family, 774 const struct genl_multicast_group *grp, 775 int grp_id, u32 portid, u32 seq, u32 flags, 776 struct sk_buff *skb, u8 cmd) 777 { 778 void *hdr; 779 struct nlattr *nla_grps; 780 struct nlattr *nest; 781 782 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 783 if (hdr == NULL) 784 return -1; 785 786 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 787 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 788 goto nla_put_failure; 789 790 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 791 if (nla_grps == NULL) 792 goto nla_put_failure; 793 794 nest = nla_nest_start(skb, 1); 795 if (nest == NULL) 796 goto nla_put_failure; 797 798 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 799 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 800 grp->name)) 801 goto nla_put_failure; 802 803 nla_nest_end(skb, nest); 804 nla_nest_end(skb, nla_grps); 805 806 genlmsg_end(skb, hdr); 807 return 0; 808 809 nla_put_failure: 810 genlmsg_cancel(skb, hdr); 811 return -EMSGSIZE; 812 } 813 814 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 815 { 816 817 int i, n = 0; 818 struct genl_family *rt; 819 struct net *net = sock_net(skb->sk); 820 int chains_to_skip = cb->args[0]; 821 int fams_to_skip = cb->args[1]; 822 823 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) { 824 n = 0; 825 list_for_each_entry(rt, genl_family_chain(i), family_list) { 826 if (!rt->netnsok && !net_eq(net, &init_net)) 827 continue; 828 if (++n < fams_to_skip) 829 continue; 830 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 831 cb->nlh->nlmsg_seq, NLM_F_MULTI, 832 skb, CTRL_CMD_NEWFAMILY) < 0) 833 goto errout; 834 } 835 836 fams_to_skip = 0; 837 } 838 839 errout: 840 cb->args[0] = i; 841 cb->args[1] = n; 842 843 return skb->len; 844 } 845 846 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 847 u32 portid, int seq, u8 cmd) 848 { 849 struct sk_buff *skb; 850 int err; 851 852 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 853 if (skb == NULL) 854 return ERR_PTR(-ENOBUFS); 855 856 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 857 if (err < 0) { 858 nlmsg_free(skb); 859 return ERR_PTR(err); 860 } 861 862 return skb; 863 } 864 865 static struct sk_buff * 866 ctrl_build_mcgrp_msg(struct genl_family *family, 867 const struct genl_multicast_group *grp, 868 int grp_id, u32 portid, int seq, u8 cmd) 869 { 870 struct sk_buff *skb; 871 int err; 872 873 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 874 if (skb == NULL) 875 return ERR_PTR(-ENOBUFS); 876 877 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 878 seq, 0, skb, cmd); 879 if (err < 0) { 880 nlmsg_free(skb); 881 return ERR_PTR(err); 882 } 883 884 return skb; 885 } 886 887 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 888 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 889 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 890 .len = GENL_NAMSIZ - 1 }, 891 }; 892 893 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 894 { 895 struct sk_buff *msg; 896 struct genl_family *res = NULL; 897 int err = -EINVAL; 898 899 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 900 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 901 res = genl_family_find_byid(id); 902 err = -ENOENT; 903 } 904 905 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 906 char *name; 907 908 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 909 res = genl_family_find_byname(name); 910 #ifdef CONFIG_MODULES 911 if (res == NULL) { 912 genl_unlock(); 913 up_read(&cb_lock); 914 request_module("net-pf-%d-proto-%d-family-%s", 915 PF_NETLINK, NETLINK_GENERIC, name); 916 down_read(&cb_lock); 917 genl_lock(); 918 res = genl_family_find_byname(name); 919 } 920 #endif 921 err = -ENOENT; 922 } 923 924 if (res == NULL) 925 return err; 926 927 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 928 /* family doesn't exist here */ 929 return -ENOENT; 930 } 931 932 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 933 CTRL_CMD_NEWFAMILY); 934 if (IS_ERR(msg)) 935 return PTR_ERR(msg); 936 937 return genlmsg_reply(msg, info); 938 } 939 940 static int genl_ctrl_event(int event, struct genl_family *family, 941 const struct genl_multicast_group *grp, 942 int grp_id) 943 { 944 struct sk_buff *msg; 945 946 /* genl is still initialising */ 947 if (!init_net.genl_sock) 948 return 0; 949 950 switch (event) { 951 case CTRL_CMD_NEWFAMILY: 952 case CTRL_CMD_DELFAMILY: 953 WARN_ON(grp); 954 msg = ctrl_build_family_msg(family, 0, 0, event); 955 break; 956 case CTRL_CMD_NEWMCAST_GRP: 957 case CTRL_CMD_DELMCAST_GRP: 958 BUG_ON(!grp); 959 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 960 break; 961 default: 962 return -EINVAL; 963 } 964 965 if (IS_ERR(msg)) 966 return PTR_ERR(msg); 967 968 if (!family->netnsok) { 969 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 970 0, GFP_KERNEL); 971 } else { 972 rcu_read_lock(); 973 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 974 0, GFP_ATOMIC); 975 rcu_read_unlock(); 976 } 977 978 return 0; 979 } 980 981 static struct genl_ops genl_ctrl_ops[] = { 982 { 983 .cmd = CTRL_CMD_GETFAMILY, 984 .doit = ctrl_getfamily, 985 .dumpit = ctrl_dumpfamily, 986 .policy = ctrl_policy, 987 }, 988 }; 989 990 static struct genl_multicast_group genl_ctrl_groups[] = { 991 { .name = "notify", }, 992 }; 993 994 static int genl_bind(struct net *net, int group) 995 { 996 int i, err = -ENOENT; 997 998 down_read(&cb_lock); 999 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 1000 struct genl_family *f; 1001 1002 list_for_each_entry(f, genl_family_chain(i), family_list) { 1003 if (group >= f->mcgrp_offset && 1004 group < f->mcgrp_offset + f->n_mcgrps) { 1005 int fam_grp = group - f->mcgrp_offset; 1006 1007 if (!f->netnsok && net != &init_net) 1008 err = -ENOENT; 1009 else if (f->mcast_bind) 1010 err = f->mcast_bind(net, fam_grp); 1011 else 1012 err = 0; 1013 break; 1014 } 1015 } 1016 } 1017 up_read(&cb_lock); 1018 1019 return err; 1020 } 1021 1022 static void genl_unbind(struct net *net, int group) 1023 { 1024 int i; 1025 1026 down_read(&cb_lock); 1027 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 1028 struct genl_family *f; 1029 1030 list_for_each_entry(f, genl_family_chain(i), family_list) { 1031 if (group >= f->mcgrp_offset && 1032 group < f->mcgrp_offset + f->n_mcgrps) { 1033 int fam_grp = group - f->mcgrp_offset; 1034 1035 if (f->mcast_unbind) 1036 f->mcast_unbind(net, fam_grp); 1037 break; 1038 } 1039 } 1040 } 1041 up_read(&cb_lock); 1042 } 1043 1044 static int __net_init genl_pernet_init(struct net *net) 1045 { 1046 struct netlink_kernel_cfg cfg = { 1047 .input = genl_rcv, 1048 .flags = NL_CFG_F_NONROOT_RECV, 1049 .bind = genl_bind, 1050 .unbind = genl_unbind, 1051 }; 1052 1053 /* we'll bump the group number right afterwards */ 1054 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1055 1056 if (!net->genl_sock && net_eq(net, &init_net)) 1057 panic("GENL: Cannot initialize generic netlink\n"); 1058 1059 if (!net->genl_sock) 1060 return -ENOMEM; 1061 1062 return 0; 1063 } 1064 1065 static void __net_exit genl_pernet_exit(struct net *net) 1066 { 1067 netlink_kernel_release(net->genl_sock); 1068 net->genl_sock = NULL; 1069 } 1070 1071 static struct pernet_operations genl_pernet_ops = { 1072 .init = genl_pernet_init, 1073 .exit = genl_pernet_exit, 1074 }; 1075 1076 static int __init genl_init(void) 1077 { 1078 int i, err; 1079 1080 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 1081 INIT_LIST_HEAD(&family_ht[i]); 1082 1083 err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops, 1084 genl_ctrl_groups); 1085 if (err < 0) 1086 goto problem; 1087 1088 err = register_pernet_subsys(&genl_pernet_ops); 1089 if (err) 1090 goto problem; 1091 1092 return 0; 1093 1094 problem: 1095 panic("GENL: Cannot register controller: %d\n", err); 1096 } 1097 1098 subsys_initcall(genl_init); 1099 1100 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1101 gfp_t flags) 1102 { 1103 struct sk_buff *tmp; 1104 struct net *net, *prev = NULL; 1105 int err; 1106 1107 for_each_net_rcu(net) { 1108 if (prev) { 1109 tmp = skb_clone(skb, flags); 1110 if (!tmp) { 1111 err = -ENOMEM; 1112 goto error; 1113 } 1114 err = nlmsg_multicast(prev->genl_sock, tmp, 1115 portid, group, flags); 1116 if (err) 1117 goto error; 1118 } 1119 1120 prev = net; 1121 } 1122 1123 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1124 error: 1125 kfree_skb(skb); 1126 return err; 1127 } 1128 1129 int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb, 1130 u32 portid, unsigned int group, gfp_t flags) 1131 { 1132 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1133 return -EINVAL; 1134 group = family->mcgrp_offset + group; 1135 return genlmsg_mcast(skb, portid, group, flags); 1136 } 1137 EXPORT_SYMBOL(genlmsg_multicast_allns); 1138 1139 void genl_notify(struct genl_family *family, 1140 struct sk_buff *skb, struct net *net, u32 portid, u32 group, 1141 struct nlmsghdr *nlh, gfp_t flags) 1142 { 1143 struct sock *sk = net->genl_sock; 1144 int report = 0; 1145 1146 if (nlh) 1147 report = nlmsg_report(nlh); 1148 1149 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1150 return; 1151 group = family->mcgrp_offset + group; 1152 nlmsg_notify(sk, skb, portid, group, report, flags); 1153 } 1154 EXPORT_SYMBOL(genl_notify); 1155