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_put - Add generic netlink header to netlink message 467 * @skb: socket buffer holding the message 468 * @portid: netlink portid the message is addressed to 469 * @seq: sequence number (usually the one of the sender) 470 * @family: generic netlink family 471 * @flags: netlink message flags 472 * @cmd: generic netlink command 473 * 474 * Returns pointer to user specific header 475 */ 476 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 477 struct genl_family *family, int flags, u8 cmd) 478 { 479 struct nlmsghdr *nlh; 480 struct genlmsghdr *hdr; 481 482 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN + 483 family->hdrsize, flags); 484 if (nlh == NULL) 485 return NULL; 486 487 hdr = nlmsg_data(nlh); 488 hdr->cmd = cmd; 489 hdr->version = family->version; 490 hdr->reserved = 0; 491 492 return (char *) hdr + GENL_HDRLEN; 493 } 494 EXPORT_SYMBOL(genlmsg_put); 495 496 static int genl_lock_start(struct netlink_callback *cb) 497 { 498 /* our ops are always const - netlink API doesn't propagate that */ 499 const struct genl_ops *ops = cb->data; 500 int rc = 0; 501 502 if (ops->start) { 503 genl_lock(); 504 rc = ops->start(cb); 505 genl_unlock(); 506 } 507 return rc; 508 } 509 510 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 511 { 512 /* our ops are always const - netlink API doesn't propagate that */ 513 const struct genl_ops *ops = cb->data; 514 int rc; 515 516 genl_lock(); 517 rc = ops->dumpit(skb, cb); 518 genl_unlock(); 519 return rc; 520 } 521 522 static int genl_lock_done(struct netlink_callback *cb) 523 { 524 /* our ops are always const - netlink API doesn't propagate that */ 525 const struct genl_ops *ops = cb->data; 526 int rc = 0; 527 528 if (ops->done) { 529 genl_lock(); 530 rc = ops->done(cb); 531 genl_unlock(); 532 } 533 return rc; 534 } 535 536 static int genl_family_rcv_msg(struct genl_family *family, 537 struct sk_buff *skb, 538 struct nlmsghdr *nlh) 539 { 540 const struct genl_ops *ops; 541 struct net *net = sock_net(skb->sk); 542 struct genl_info info; 543 struct genlmsghdr *hdr = nlmsg_data(nlh); 544 struct nlattr **attrbuf; 545 int hdrlen, err; 546 547 /* this family doesn't exist in this netns */ 548 if (!family->netnsok && !net_eq(net, &init_net)) 549 return -ENOENT; 550 551 hdrlen = GENL_HDRLEN + family->hdrsize; 552 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 553 return -EINVAL; 554 555 ops = genl_get_cmd(hdr->cmd, family); 556 if (ops == NULL) 557 return -EOPNOTSUPP; 558 559 if ((ops->flags & GENL_ADMIN_PERM) && 560 !netlink_capable(skb, CAP_NET_ADMIN)) 561 return -EPERM; 562 563 if ((ops->flags & GENL_UNS_ADMIN_PERM) && 564 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) 565 return -EPERM; 566 567 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) { 568 int rc; 569 570 if (ops->dumpit == NULL) 571 return -EOPNOTSUPP; 572 573 if (!family->parallel_ops) { 574 struct netlink_dump_control c = { 575 .module = family->module, 576 /* we have const, but the netlink API doesn't */ 577 .data = (void *)ops, 578 .start = genl_lock_start, 579 .dump = genl_lock_dumpit, 580 .done = genl_lock_done, 581 }; 582 583 genl_unlock(); 584 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 585 genl_lock(); 586 587 } else { 588 struct netlink_dump_control c = { 589 .module = family->module, 590 .start = ops->start, 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 genl_info_net_set(&info, net); 626 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 627 628 if (family->pre_doit) { 629 err = family->pre_doit(ops, skb, &info); 630 if (err) 631 goto out; 632 } 633 634 err = ops->doit(skb, &info); 635 636 if (family->post_doit) 637 family->post_doit(ops, skb, &info); 638 639 out: 640 if (family->parallel_ops) 641 kfree(attrbuf); 642 643 return err; 644 } 645 646 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 647 { 648 struct genl_family *family; 649 int err; 650 651 family = genl_family_find_byid(nlh->nlmsg_type); 652 if (family == NULL) 653 return -ENOENT; 654 655 if (!family->parallel_ops) 656 genl_lock(); 657 658 err = genl_family_rcv_msg(family, skb, nlh); 659 660 if (!family->parallel_ops) 661 genl_unlock(); 662 663 return err; 664 } 665 666 static void genl_rcv(struct sk_buff *skb) 667 { 668 down_read(&cb_lock); 669 netlink_rcv_skb(skb, &genl_rcv_msg); 670 up_read(&cb_lock); 671 } 672 673 /************************************************************************** 674 * Controller 675 **************************************************************************/ 676 677 static struct genl_family genl_ctrl = { 678 .id = GENL_ID_CTRL, 679 .name = "nlctrl", 680 .version = 0x2, 681 .maxattr = CTRL_ATTR_MAX, 682 .netnsok = true, 683 }; 684 685 static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq, 686 u32 flags, struct sk_buff *skb, u8 cmd) 687 { 688 void *hdr; 689 690 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 691 if (hdr == NULL) 692 return -1; 693 694 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 695 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 696 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 697 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 698 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 699 goto nla_put_failure; 700 701 if (family->n_ops) { 702 struct nlattr *nla_ops; 703 int i; 704 705 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); 706 if (nla_ops == NULL) 707 goto nla_put_failure; 708 709 for (i = 0; i < family->n_ops; i++) { 710 struct nlattr *nest; 711 const struct genl_ops *ops = &family->ops[i]; 712 u32 op_flags = ops->flags; 713 714 if (ops->dumpit) 715 op_flags |= GENL_CMD_CAP_DUMP; 716 if (ops->doit) 717 op_flags |= GENL_CMD_CAP_DO; 718 if (ops->policy) 719 op_flags |= GENL_CMD_CAP_HASPOL; 720 721 nest = nla_nest_start(skb, i + 1); 722 if (nest == NULL) 723 goto nla_put_failure; 724 725 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 726 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 727 goto nla_put_failure; 728 729 nla_nest_end(skb, nest); 730 } 731 732 nla_nest_end(skb, nla_ops); 733 } 734 735 if (family->n_mcgrps) { 736 struct nlattr *nla_grps; 737 int i; 738 739 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 740 if (nla_grps == NULL) 741 goto nla_put_failure; 742 743 for (i = 0; i < family->n_mcgrps; i++) { 744 struct nlattr *nest; 745 const struct genl_multicast_group *grp; 746 747 grp = &family->mcgrps[i]; 748 749 nest = nla_nest_start(skb, i + 1); 750 if (nest == NULL) 751 goto nla_put_failure; 752 753 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 754 family->mcgrp_offset + i) || 755 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 756 grp->name)) 757 goto nla_put_failure; 758 759 nla_nest_end(skb, nest); 760 } 761 nla_nest_end(skb, nla_grps); 762 } 763 764 genlmsg_end(skb, hdr); 765 return 0; 766 767 nla_put_failure: 768 genlmsg_cancel(skb, hdr); 769 return -EMSGSIZE; 770 } 771 772 static int ctrl_fill_mcgrp_info(struct genl_family *family, 773 const struct genl_multicast_group *grp, 774 int grp_id, u32 portid, u32 seq, u32 flags, 775 struct sk_buff *skb, u8 cmd) 776 { 777 void *hdr; 778 struct nlattr *nla_grps; 779 struct nlattr *nest; 780 781 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 782 if (hdr == NULL) 783 return -1; 784 785 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 786 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 787 goto nla_put_failure; 788 789 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); 790 if (nla_grps == NULL) 791 goto nla_put_failure; 792 793 nest = nla_nest_start(skb, 1); 794 if (nest == NULL) 795 goto nla_put_failure; 796 797 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 798 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 799 grp->name)) 800 goto nla_put_failure; 801 802 nla_nest_end(skb, nest); 803 nla_nest_end(skb, nla_grps); 804 805 genlmsg_end(skb, hdr); 806 return 0; 807 808 nla_put_failure: 809 genlmsg_cancel(skb, hdr); 810 return -EMSGSIZE; 811 } 812 813 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 814 { 815 816 int i, n = 0; 817 struct genl_family *rt; 818 struct net *net = sock_net(skb->sk); 819 int chains_to_skip = cb->args[0]; 820 int fams_to_skip = cb->args[1]; 821 822 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) { 823 n = 0; 824 list_for_each_entry(rt, genl_family_chain(i), family_list) { 825 if (!rt->netnsok && !net_eq(net, &init_net)) 826 continue; 827 if (++n < fams_to_skip) 828 continue; 829 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 830 cb->nlh->nlmsg_seq, NLM_F_MULTI, 831 skb, CTRL_CMD_NEWFAMILY) < 0) 832 goto errout; 833 } 834 835 fams_to_skip = 0; 836 } 837 838 errout: 839 cb->args[0] = i; 840 cb->args[1] = n; 841 842 return skb->len; 843 } 844 845 static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, 846 u32 portid, int seq, u8 cmd) 847 { 848 struct sk_buff *skb; 849 int err; 850 851 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 852 if (skb == NULL) 853 return ERR_PTR(-ENOBUFS); 854 855 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 856 if (err < 0) { 857 nlmsg_free(skb); 858 return ERR_PTR(err); 859 } 860 861 return skb; 862 } 863 864 static struct sk_buff * 865 ctrl_build_mcgrp_msg(struct genl_family *family, 866 const struct genl_multicast_group *grp, 867 int grp_id, u32 portid, int seq, u8 cmd) 868 { 869 struct sk_buff *skb; 870 int err; 871 872 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 873 if (skb == NULL) 874 return ERR_PTR(-ENOBUFS); 875 876 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 877 seq, 0, skb, cmd); 878 if (err < 0) { 879 nlmsg_free(skb); 880 return ERR_PTR(err); 881 } 882 883 return skb; 884 } 885 886 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 887 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 888 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 889 .len = GENL_NAMSIZ - 1 }, 890 }; 891 892 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 893 { 894 struct sk_buff *msg; 895 struct genl_family *res = NULL; 896 int err = -EINVAL; 897 898 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 899 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 900 res = genl_family_find_byid(id); 901 err = -ENOENT; 902 } 903 904 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 905 char *name; 906 907 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 908 res = genl_family_find_byname(name); 909 #ifdef CONFIG_MODULES 910 if (res == NULL) { 911 genl_unlock(); 912 up_read(&cb_lock); 913 request_module("net-pf-%d-proto-%d-family-%s", 914 PF_NETLINK, NETLINK_GENERIC, name); 915 down_read(&cb_lock); 916 genl_lock(); 917 res = genl_family_find_byname(name); 918 } 919 #endif 920 err = -ENOENT; 921 } 922 923 if (res == NULL) 924 return err; 925 926 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 927 /* family doesn't exist here */ 928 return -ENOENT; 929 } 930 931 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 932 CTRL_CMD_NEWFAMILY); 933 if (IS_ERR(msg)) 934 return PTR_ERR(msg); 935 936 return genlmsg_reply(msg, info); 937 } 938 939 static int genl_ctrl_event(int event, struct genl_family *family, 940 const struct genl_multicast_group *grp, 941 int grp_id) 942 { 943 struct sk_buff *msg; 944 945 /* genl is still initialising */ 946 if (!init_net.genl_sock) 947 return 0; 948 949 switch (event) { 950 case CTRL_CMD_NEWFAMILY: 951 case CTRL_CMD_DELFAMILY: 952 WARN_ON(grp); 953 msg = ctrl_build_family_msg(family, 0, 0, event); 954 break; 955 case CTRL_CMD_NEWMCAST_GRP: 956 case CTRL_CMD_DELMCAST_GRP: 957 BUG_ON(!grp); 958 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 959 break; 960 default: 961 return -EINVAL; 962 } 963 964 if (IS_ERR(msg)) 965 return PTR_ERR(msg); 966 967 if (!family->netnsok) { 968 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 969 0, GFP_KERNEL); 970 } else { 971 rcu_read_lock(); 972 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 973 0, GFP_ATOMIC); 974 rcu_read_unlock(); 975 } 976 977 return 0; 978 } 979 980 static struct genl_ops genl_ctrl_ops[] = { 981 { 982 .cmd = CTRL_CMD_GETFAMILY, 983 .doit = ctrl_getfamily, 984 .dumpit = ctrl_dumpfamily, 985 .policy = ctrl_policy, 986 }, 987 }; 988 989 static struct genl_multicast_group genl_ctrl_groups[] = { 990 { .name = "notify", }, 991 }; 992 993 static int genl_bind(struct net *net, int group) 994 { 995 int i, err = -ENOENT; 996 997 down_read(&cb_lock); 998 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 999 struct genl_family *f; 1000 1001 list_for_each_entry(f, genl_family_chain(i), family_list) { 1002 if (group >= f->mcgrp_offset && 1003 group < f->mcgrp_offset + f->n_mcgrps) { 1004 int fam_grp = group - f->mcgrp_offset; 1005 1006 if (!f->netnsok && net != &init_net) 1007 err = -ENOENT; 1008 else if (f->mcast_bind) 1009 err = f->mcast_bind(net, fam_grp); 1010 else 1011 err = 0; 1012 break; 1013 } 1014 } 1015 } 1016 up_read(&cb_lock); 1017 1018 return err; 1019 } 1020 1021 static void genl_unbind(struct net *net, int group) 1022 { 1023 int i; 1024 1025 down_read(&cb_lock); 1026 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { 1027 struct genl_family *f; 1028 1029 list_for_each_entry(f, genl_family_chain(i), family_list) { 1030 if (group >= f->mcgrp_offset && 1031 group < f->mcgrp_offset + f->n_mcgrps) { 1032 int fam_grp = group - f->mcgrp_offset; 1033 1034 if (f->mcast_unbind) 1035 f->mcast_unbind(net, fam_grp); 1036 break; 1037 } 1038 } 1039 } 1040 up_read(&cb_lock); 1041 } 1042 1043 static int __net_init genl_pernet_init(struct net *net) 1044 { 1045 struct netlink_kernel_cfg cfg = { 1046 .input = genl_rcv, 1047 .flags = NL_CFG_F_NONROOT_RECV, 1048 .bind = genl_bind, 1049 .unbind = genl_unbind, 1050 }; 1051 1052 /* we'll bump the group number right afterwards */ 1053 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1054 1055 if (!net->genl_sock && net_eq(net, &init_net)) 1056 panic("GENL: Cannot initialize generic netlink\n"); 1057 1058 if (!net->genl_sock) 1059 return -ENOMEM; 1060 1061 return 0; 1062 } 1063 1064 static void __net_exit genl_pernet_exit(struct net *net) 1065 { 1066 netlink_kernel_release(net->genl_sock); 1067 net->genl_sock = NULL; 1068 } 1069 1070 static struct pernet_operations genl_pernet_ops = { 1071 .init = genl_pernet_init, 1072 .exit = genl_pernet_exit, 1073 }; 1074 1075 static int __init genl_init(void) 1076 { 1077 int i, err; 1078 1079 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) 1080 INIT_LIST_HEAD(&family_ht[i]); 1081 1082 err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops, 1083 genl_ctrl_groups); 1084 if (err < 0) 1085 goto problem; 1086 1087 err = register_pernet_subsys(&genl_pernet_ops); 1088 if (err) 1089 goto problem; 1090 1091 return 0; 1092 1093 problem: 1094 panic("GENL: Cannot register controller: %d\n", err); 1095 } 1096 1097 subsys_initcall(genl_init); 1098 1099 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1100 gfp_t flags) 1101 { 1102 struct sk_buff *tmp; 1103 struct net *net, *prev = NULL; 1104 int err; 1105 1106 for_each_net_rcu(net) { 1107 if (prev) { 1108 tmp = skb_clone(skb, flags); 1109 if (!tmp) { 1110 err = -ENOMEM; 1111 goto error; 1112 } 1113 err = nlmsg_multicast(prev->genl_sock, tmp, 1114 portid, group, flags); 1115 if (err) 1116 goto error; 1117 } 1118 1119 prev = net; 1120 } 1121 1122 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1123 error: 1124 kfree_skb(skb); 1125 return err; 1126 } 1127 1128 int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb, 1129 u32 portid, unsigned int group, gfp_t flags) 1130 { 1131 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1132 return -EINVAL; 1133 group = family->mcgrp_offset + group; 1134 return genlmsg_mcast(skb, portid, group, flags); 1135 } 1136 EXPORT_SYMBOL(genlmsg_multicast_allns); 1137 1138 void genl_notify(struct genl_family *family, struct sk_buff *skb, 1139 struct genl_info *info, u32 group, gfp_t flags) 1140 { 1141 struct net *net = genl_info_net(info); 1142 struct sock *sk = net->genl_sock; 1143 int report = 0; 1144 1145 if (info->nlhdr) 1146 report = nlmsg_report(info->nlhdr); 1147 1148 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1149 return; 1150 group = family->mcgrp_offset + group; 1151 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); 1152 } 1153 EXPORT_SYMBOL(genl_notify); 1154