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_free; 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_free: 421 kfree(family->attrbuf); 422 errout_locked: 423 genl_unlock_all(); 424 errout: 425 return err; 426 } 427 EXPORT_SYMBOL(__genl_register_family); 428 429 /** 430 * genl_unregister_family - unregister generic netlink family 431 * @family: generic netlink family 432 * 433 * Unregisters the specified family. 434 * 435 * Returns 0 on success or a negative error code. 436 */ 437 int genl_unregister_family(struct genl_family *family) 438 { 439 struct genl_family *rc; 440 441 genl_lock_all(); 442 443 list_for_each_entry(rc, genl_family_chain(family->id), family_list) { 444 if (family->id != rc->id || strcmp(rc->name, family->name)) 445 continue; 446 447 genl_unregister_mc_groups(family); 448 449 list_del(&rc->family_list); 450 family->n_ops = 0; 451 up_write(&cb_lock); 452 wait_event(genl_sk_destructing_waitq, 453 atomic_read(&genl_sk_destructing_cnt) == 0); 454 genl_unlock(); 455 456 kfree(family->attrbuf); 457 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); 458 return 0; 459 } 460 461 genl_unlock_all(); 462 463 return -ENOENT; 464 } 465 EXPORT_SYMBOL(genl_unregister_family); 466 467 /** 468 * genlmsg_put - Add generic netlink header to netlink message 469 * @skb: socket buffer holding the message 470 * @portid: netlink portid the message is addressed to 471 * @seq: sequence number (usually the one of the sender) 472 * @family: generic netlink family 473 * @flags: netlink message flags 474 * @cmd: generic netlink command 475 * 476 * Returns pointer to user specific header 477 */ 478 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 479 struct genl_family *family, int flags, u8 cmd) 480 { 481 struct nlmsghdr *nlh; 482 struct genlmsghdr *hdr; 483 484 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN + 485 family->hdrsize, flags); 486 if (nlh == NULL) 487 return NULL; 488 489 hdr = nlmsg_data(nlh); 490 hdr->cmd = cmd; 491 hdr->version = family->version; 492 hdr->reserved = 0; 493 494 return (char *) hdr + GENL_HDRLEN; 495 } 496 EXPORT_SYMBOL(genlmsg_put); 497 498 static int genl_lock_start(struct netlink_callback *cb) 499 { 500 /* our ops are always const - netlink API doesn't propagate that */ 501 const struct genl_ops *ops = cb->data; 502 int rc = 0; 503 504 if (ops->start) { 505 genl_lock(); 506 rc = ops->start(cb); 507 genl_unlock(); 508 } 509 return rc; 510 } 511 512 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 513 { 514 /* our ops are always const - netlink API doesn't propagate that */ 515 const struct genl_ops *ops = cb->data; 516 int rc; 517 518 genl_lock(); 519 rc = ops->dumpit(skb, cb); 520 genl_unlock(); 521 return rc; 522 } 523 524 static int genl_lock_done(struct netlink_callback *cb) 525 { 526 /* our ops are always const - netlink API doesn't propagate that */ 527 const struct genl_ops *ops = cb->data; 528 int rc = 0; 529 530 if (ops->done) { 531 genl_lock(); 532 rc = ops->done(cb); 533 genl_unlock(); 534 } 535 return rc; 536 } 537 538 static int genl_family_rcv_msg(struct genl_family *family, 539 struct sk_buff *skb, 540 struct nlmsghdr *nlh) 541 { 542 const struct genl_ops *ops; 543 struct net *net = sock_net(skb->sk); 544 struct genl_info info; 545 struct genlmsghdr *hdr = nlmsg_data(nlh); 546 struct nlattr **attrbuf; 547 int hdrlen, err; 548 549 /* this family doesn't exist in this netns */ 550 if (!family->netnsok && !net_eq(net, &init_net)) 551 return -ENOENT; 552 553 hdrlen = GENL_HDRLEN + family->hdrsize; 554 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 555 return -EINVAL; 556 557 ops = genl_get_cmd(hdr->cmd, family); 558 if (ops == NULL) 559 return -EOPNOTSUPP; 560 561 if ((ops->flags & GENL_ADMIN_PERM) && 562 !netlink_capable(skb, CAP_NET_ADMIN)) 563 return -EPERM; 564 565 if ((ops->flags & GENL_UNS_ADMIN_PERM) && 566 !netlink_ns_capable(skb, net->user_ns, 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 .start = genl_lock_start, 581 .dump = genl_lock_dumpit, 582 .done = genl_lock_done, 583 }; 584 585 genl_unlock(); 586 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 587 genl_lock(); 588 589 } else { 590 struct netlink_dump_control c = { 591 .module = family->module, 592 .start = ops->start, 593 .dump = ops->dumpit, 594 .done = ops->done, 595 }; 596 597 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 598 } 599 600 return rc; 601 } 602 603 if (ops->doit == NULL) 604 return -EOPNOTSUPP; 605 606 if (family->maxattr && family->parallel_ops) { 607 attrbuf = kmalloc((family->maxattr+1) * 608 sizeof(struct nlattr *), GFP_KERNEL); 609 if (attrbuf == NULL) 610 return -ENOMEM; 611 } else 612 attrbuf = family->attrbuf; 613 614 if (attrbuf) { 615 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, 616 ops->policy); 617 if (err < 0) 618 goto out; 619 } 620 621 info.snd_seq = nlh->nlmsg_seq; 622 info.snd_portid = NETLINK_CB(skb).portid; 623 info.nlhdr = nlh; 624 info.genlhdr = nlmsg_data(nlh); 625 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 626 info.attrs = attrbuf; 627 genl_info_net_set(&info, net); 628 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 629 630 if (family->pre_doit) { 631 err = family->pre_doit(ops, skb, &info); 632 if (err) 633 goto out; 634 } 635 636 err = ops->doit(skb, &info); 637 638 if (family->post_doit) 639 family->post_doit(ops, skb, &info); 640 641 out: 642 if (family->parallel_ops) 643 kfree(attrbuf); 644 645 return err; 646 } 647 648 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 649 { 650 struct genl_family *family; 651 int err; 652 653 family = genl_family_find_byid(nlh->nlmsg_type); 654 if (family == NULL) 655 return -ENOENT; 656 657 if (!family->parallel_ops) 658 genl_lock(); 659 660 err = genl_family_rcv_msg(family, skb, nlh); 661 662 if (!family->parallel_ops) 663 genl_unlock(); 664 665 return err; 666 } 667 668 static void genl_rcv(struct sk_buff *skb) 669 { 670 down_read(&cb_lock); 671 netlink_rcv_skb(skb, &genl_rcv_msg); 672 up_read(&cb_lock); 673 } 674 675 /************************************************************************** 676 * Controller 677 **************************************************************************/ 678 679 static struct genl_family genl_ctrl = { 680 .id = GENL_ID_CTRL, 681 .name = "nlctrl", 682 .version = 0x2, 683 .maxattr = CTRL_ATTR_MAX, 684 .netnsok = true, 685 }; 686 687 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq, 688 u32 flags, struct sk_buff *skb, u8 cmd) 689 { 690 void *hdr; 691 692 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 693 if (hdr == NULL) 694 return -1; 695 696 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 697 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 698 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 699 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 700 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 701 goto nla_put_failure; 702 703 if (family->n_ops) { 704 struct nlattr *nla_ops; 705 int i; 706 707 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 708 if (nla_ops == NULL) 709 goto nla_put_failure; 710 711 for (i = 0; i < family->n_ops; i++) { 712 struct nlattr *nest; 713 const struct genl_ops *ops = &family->ops[i]; 714 u32 op_flags = ops->flags; 715 716 if (ops->dumpit) 717 op_flags |= GENL_CMD_CAP_DUMP; 718 if (ops->doit) 719 op_flags |= GENL_CMD_CAP_DO; 720 if (ops->policy) 721 op_flags |= GENL_CMD_CAP_HASPOL; 722 723 nest = nla_nest_start(skb, i + 1); 724 if (nest == NULL) 725 goto nla_put_failure; 726 727 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 728 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 729 goto nla_put_failure; 730 731 nla_nest_end(skb, nest); 732 } 733 734 nla_nest_end(skb, nla_ops); 735 } 736 737 if (family->n_mcgrps) { 738 struct nlattr *nla_grps; 739 int i; 740 741 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 742 if (nla_grps == NULL) 743 goto nla_put_failure; 744 745 for (i = 0; i < family->n_mcgrps; i++) { 746 struct nlattr *nest; 747 const struct genl_multicast_group *grp; 748 749 grp = &family->mcgrps[i]; 750 751 nest = nla_nest_start(skb, i + 1); 752 if (nest == NULL) 753 goto nla_put_failure; 754 755 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 756 family->mcgrp_offset + i) || 757 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 758 grp->name)) 759 goto nla_put_failure; 760 761 nla_nest_end(skb, nest); 762 } 763 nla_nest_end(skb, nla_grps); 764 } 765 766 genlmsg_end(skb, hdr); 767 return 0; 768 769 nla_put_failure: 770 genlmsg_cancel(skb, hdr); 771 return -EMSGSIZE; 772 } 773 774 static int ctrl_fill_mcgrp_info(struct genl_family *family, 775 const struct genl_multicast_group *grp, 776 int grp_id, u32 portid, u32 seq, u32 flags, 777 struct sk_buff *skb, u8 cmd) 778 { 779 void *hdr; 780 struct nlattr *nla_grps; 781 struct nlattr *nest; 782 783 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 784 if (hdr == NULL) 785 return -1; 786 787 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 788 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 789 goto nla_put_failure; 790 791 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 792 if (nla_grps == NULL) 793 goto nla_put_failure; 794 795 nest = nla_nest_start(skb, 1); 796 if (nest == NULL) 797 goto nla_put_failure; 798 799 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 800 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 801 grp->name)) 802 goto nla_put_failure; 803 804 nla_nest_end(skb, nest); 805 nla_nest_end(skb, nla_grps); 806 807 genlmsg_end(skb, hdr); 808 return 0; 809 810 nla_put_failure: 811 genlmsg_cancel(skb, hdr); 812 return -EMSGSIZE; 813 } 814 815 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 816 { 817 818 int i, n = 0; 819 struct genl_family *rt; 820 struct net *net = sock_net(skb->sk); 821 int chains_to_skip = cb->args[0]; 822 int fams_to_skip = cb->args[1]; 823 824 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) { 825 n = 0; 826 list_for_each_entry(rt, genl_family_chain(i), family_list) { 827 if (!rt->netnsok && !net_eq(net, &init_net)) 828 continue; 829 if (++n < fams_to_skip) 830 continue; 831 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 832 cb->nlh->nlmsg_seq, NLM_F_MULTI, 833 skb, CTRL_CMD_NEWFAMILY) < 0) 834 goto errout; 835 } 836 837 fams_to_skip = 0; 838 } 839 840 errout: 841 cb->args[0] = i; 842 cb->args[1] = n; 843 844 return skb->len; 845 } 846 847 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 848 u32 portid, int seq, u8 cmd) 849 { 850 struct sk_buff *skb; 851 int err; 852 853 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 854 if (skb == NULL) 855 return ERR_PTR(-ENOBUFS); 856 857 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 858 if (err < 0) { 859 nlmsg_free(skb); 860 return ERR_PTR(err); 861 } 862 863 return skb; 864 } 865 866 static struct sk_buff * 867 ctrl_build_mcgrp_msg(struct genl_family *family, 868 const struct genl_multicast_group *grp, 869 int grp_id, u32 portid, int seq, u8 cmd) 870 { 871 struct sk_buff *skb; 872 int err; 873 874 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 875 if (skb == NULL) 876 return ERR_PTR(-ENOBUFS); 877 878 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 879 seq, 0, skb, cmd); 880 if (err < 0) { 881 nlmsg_free(skb); 882 return ERR_PTR(err); 883 } 884 885 return skb; 886 } 887 888 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 889 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 890 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 891 .len = GENL_NAMSIZ - 1 }, 892 }; 893 894 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 895 { 896 struct sk_buff *msg; 897 struct genl_family *res = NULL; 898 int err = -EINVAL; 899 900 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 901 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 902 res = genl_family_find_byid(id); 903 err = -ENOENT; 904 } 905 906 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 907 char *name; 908 909 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 910 res = genl_family_find_byname(name); 911 #ifdef CONFIG_MODULES 912 if (res == NULL) { 913 genl_unlock(); 914 up_read(&cb_lock); 915 request_module("net-pf-%d-proto-%d-family-%s", 916 PF_NETLINK, NETLINK_GENERIC, name); 917 down_read(&cb_lock); 918 genl_lock(); 919 res = genl_family_find_byname(name); 920 } 921 #endif 922 err = -ENOENT; 923 } 924 925 if (res == NULL) 926 return err; 927 928 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 929 /* family doesn't exist here */ 930 return -ENOENT; 931 } 932 933 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 934 CTRL_CMD_NEWFAMILY); 935 if (IS_ERR(msg)) 936 return PTR_ERR(msg); 937 938 return genlmsg_reply(msg, info); 939 } 940 941 static int genl_ctrl_event(int event, struct genl_family *family, 942 const struct genl_multicast_group *grp, 943 int grp_id) 944 { 945 struct sk_buff *msg; 946 947 /* genl is still initialising */ 948 if (!init_net.genl_sock) 949 return 0; 950 951 switch (event) { 952 case CTRL_CMD_NEWFAMILY: 953 case CTRL_CMD_DELFAMILY: 954 WARN_ON(grp); 955 msg = ctrl_build_family_msg(family, 0, 0, event); 956 break; 957 case CTRL_CMD_NEWMCAST_GRP: 958 case CTRL_CMD_DELMCAST_GRP: 959 BUG_ON(!grp); 960 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 961 break; 962 default: 963 return -EINVAL; 964 } 965 966 if (IS_ERR(msg)) 967 return PTR_ERR(msg); 968 969 if (!family->netnsok) { 970 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 971 0, GFP_KERNEL); 972 } else { 973 rcu_read_lock(); 974 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 975 0, GFP_ATOMIC); 976 rcu_read_unlock(); 977 } 978 979 return 0; 980 } 981 982 static const struct genl_ops genl_ctrl_ops[] = { 983 { 984 .cmd = CTRL_CMD_GETFAMILY, 985 .doit = ctrl_getfamily, 986 .dumpit = ctrl_dumpfamily, 987 .policy = ctrl_policy, 988 }, 989 }; 990 991 static const struct genl_multicast_group genl_ctrl_groups[] = { 992 { .name = "notify", }, 993 }; 994 995 static int genl_bind(struct net *net, int group) 996 { 997 int i, err = -ENOENT; 998 999 down_read(&cb_lock); 1000 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 1001 struct genl_family *f; 1002 1003 list_for_each_entry(f, genl_family_chain(i), family_list) { 1004 if (group >= f->mcgrp_offset && 1005 group < f->mcgrp_offset + f->n_mcgrps) { 1006 int fam_grp = group - f->mcgrp_offset; 1007 1008 if (!f->netnsok && net != &init_net) 1009 err = -ENOENT; 1010 else if (f->mcast_bind) 1011 err = f->mcast_bind(net, fam_grp); 1012 else 1013 err = 0; 1014 break; 1015 } 1016 } 1017 } 1018 up_read(&cb_lock); 1019 1020 return err; 1021 } 1022 1023 static void genl_unbind(struct net *net, int group) 1024 { 1025 int i; 1026 1027 down_read(&cb_lock); 1028 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 1029 struct genl_family *f; 1030 1031 list_for_each_entry(f, genl_family_chain(i), family_list) { 1032 if (group >= f->mcgrp_offset && 1033 group < f->mcgrp_offset + f->n_mcgrps) { 1034 int fam_grp = group - f->mcgrp_offset; 1035 1036 if (f->mcast_unbind) 1037 f->mcast_unbind(net, fam_grp); 1038 break; 1039 } 1040 } 1041 } 1042 up_read(&cb_lock); 1043 } 1044 1045 static int __net_init genl_pernet_init(struct net *net) 1046 { 1047 struct netlink_kernel_cfg cfg = { 1048 .input = genl_rcv, 1049 .flags = NL_CFG_F_NONROOT_RECV, 1050 .bind = genl_bind, 1051 .unbind = genl_unbind, 1052 }; 1053 1054 /* we'll bump the group number right afterwards */ 1055 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1056 1057 if (!net->genl_sock && net_eq(net, &init_net)) 1058 panic("GENL: Cannot initialize generic netlink\n"); 1059 1060 if (!net->genl_sock) 1061 return -ENOMEM; 1062 1063 return 0; 1064 } 1065 1066 static void __net_exit genl_pernet_exit(struct net *net) 1067 { 1068 netlink_kernel_release(net->genl_sock); 1069 net->genl_sock = NULL; 1070 } 1071 1072 static struct pernet_operations genl_pernet_ops = { 1073 .init = genl_pernet_init, 1074 .exit = genl_pernet_exit, 1075 }; 1076 1077 static int __init genl_init(void) 1078 { 1079 int i, err; 1080 1081 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 1082 INIT_LIST_HEAD(&family_ht[i]); 1083 1084 err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops, 1085 genl_ctrl_groups); 1086 if (err < 0) 1087 goto problem; 1088 1089 err = register_pernet_subsys(&genl_pernet_ops); 1090 if (err) 1091 goto problem; 1092 1093 return 0; 1094 1095 problem: 1096 panic("GENL: Cannot register controller: %d\n", err); 1097 } 1098 1099 subsys_initcall(genl_init); 1100 1101 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1102 gfp_t flags) 1103 { 1104 struct sk_buff *tmp; 1105 struct net *net, *prev = NULL; 1106 int err; 1107 1108 for_each_net_rcu(net) { 1109 if (prev) { 1110 tmp = skb_clone(skb, flags); 1111 if (!tmp) { 1112 err = -ENOMEM; 1113 goto error; 1114 } 1115 err = nlmsg_multicast(prev->genl_sock, tmp, 1116 portid, group, flags); 1117 if (err) 1118 goto error; 1119 } 1120 1121 prev = net; 1122 } 1123 1124 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1125 error: 1126 kfree_skb(skb); 1127 return err; 1128 } 1129 1130 int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb, 1131 u32 portid, unsigned int group, gfp_t flags) 1132 { 1133 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1134 return -EINVAL; 1135 group = family->mcgrp_offset + group; 1136 return genlmsg_mcast(skb, portid, group, flags); 1137 } 1138 EXPORT_SYMBOL(genlmsg_multicast_allns); 1139 1140 void genl_notify(struct genl_family *family, struct sk_buff *skb, 1141 struct genl_info *info, u32 group, gfp_t flags) 1142 { 1143 struct net *net = genl_info_net(info); 1144 struct sock *sk = net->genl_sock; 1145 int report = 0; 1146 1147 if (info->nlhdr) 1148 report = nlmsg_report(info->nlhdr); 1149 1150 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1151 return; 1152 group = family->mcgrp_offset + group; 1153 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); 1154 } 1155 EXPORT_SYMBOL(genl_notify); 1156