1 /* 2 * NETLINK Kernel-user communication protocol. 3 * 4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> 5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith 13 * added netlink_proto_exit 14 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br> 15 * use nlk_sk, as sk->protinfo is on a diet 8) 16 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org> 17 * - inc module use count of module that owns 18 * the kernel socket in case userspace opens 19 * socket of same protocol 20 * - remove all module support, since netlink is 21 * mandatory if CONFIG_NET=y these days 22 */ 23 24 #include <linux/module.h> 25 26 #include <linux/capability.h> 27 #include <linux/kernel.h> 28 #include <linux/init.h> 29 #include <linux/signal.h> 30 #include <linux/sched.h> 31 #include <linux/errno.h> 32 #include <linux/string.h> 33 #include <linux/stat.h> 34 #include <linux/socket.h> 35 #include <linux/un.h> 36 #include <linux/fcntl.h> 37 #include <linux/termios.h> 38 #include <linux/sockios.h> 39 #include <linux/net.h> 40 #include <linux/fs.h> 41 #include <linux/slab.h> 42 #include <asm/uaccess.h> 43 #include <linux/skbuff.h> 44 #include <linux/netdevice.h> 45 #include <linux/rtnetlink.h> 46 #include <linux/proc_fs.h> 47 #include <linux/seq_file.h> 48 #include <linux/notifier.h> 49 #include <linux/security.h> 50 #include <linux/jhash.h> 51 #include <linux/jiffies.h> 52 #include <linux/random.h> 53 #include <linux/bitops.h> 54 #include <linux/mm.h> 55 #include <linux/types.h> 56 #include <linux/audit.h> 57 #include <linux/mutex.h> 58 59 #include <net/net_namespace.h> 60 #include <net/sock.h> 61 #include <net/scm.h> 62 #include <net/netlink.h> 63 64 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) 65 #define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long)) 66 67 struct netlink_sock { 68 /* struct sock has to be the first member of netlink_sock */ 69 struct sock sk; 70 u32 pid; 71 u32 dst_pid; 72 u32 dst_group; 73 u32 flags; 74 u32 subscriptions; 75 u32 ngroups; 76 unsigned long *groups; 77 unsigned long state; 78 wait_queue_head_t wait; 79 struct netlink_callback *cb; 80 struct mutex *cb_mutex; 81 struct mutex cb_def_mutex; 82 void (*netlink_rcv)(struct sk_buff *skb); 83 void (*netlink_bind)(int group); 84 struct module *module; 85 }; 86 87 struct listeners { 88 struct rcu_head rcu; 89 unsigned long masks[0]; 90 }; 91 92 #define NETLINK_KERNEL_SOCKET 0x1 93 #define NETLINK_RECV_PKTINFO 0x2 94 #define NETLINK_BROADCAST_SEND_ERROR 0x4 95 #define NETLINK_RECV_NO_ENOBUFS 0x8 96 97 static inline struct netlink_sock *nlk_sk(struct sock *sk) 98 { 99 return container_of(sk, struct netlink_sock, sk); 100 } 101 102 static inline int netlink_is_kernel(struct sock *sk) 103 { 104 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET; 105 } 106 107 struct nl_pid_hash { 108 struct hlist_head *table; 109 unsigned long rehash_time; 110 111 unsigned int mask; 112 unsigned int shift; 113 114 unsigned int entries; 115 unsigned int max_shift; 116 117 u32 rnd; 118 }; 119 120 struct netlink_table { 121 struct nl_pid_hash hash; 122 struct hlist_head mc_list; 123 struct listeners __rcu *listeners; 124 unsigned int nl_nonroot; 125 unsigned int groups; 126 struct mutex *cb_mutex; 127 struct module *module; 128 void (*bind)(int group); 129 int registered; 130 }; 131 132 static struct netlink_table *nl_table; 133 134 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); 135 136 static int netlink_dump(struct sock *sk); 137 138 static DEFINE_RWLOCK(nl_table_lock); 139 static atomic_t nl_table_users = ATOMIC_INIT(0); 140 141 static ATOMIC_NOTIFIER_HEAD(netlink_chain); 142 143 static inline u32 netlink_group_mask(u32 group) 144 { 145 return group ? 1 << (group - 1) : 0; 146 } 147 148 static inline struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid) 149 { 150 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask]; 151 } 152 153 static void netlink_destroy_callback(struct netlink_callback *cb) 154 { 155 kfree_skb(cb->skb); 156 kfree(cb); 157 } 158 159 static void netlink_consume_callback(struct netlink_callback *cb) 160 { 161 consume_skb(cb->skb); 162 kfree(cb); 163 } 164 165 static void netlink_sock_destruct(struct sock *sk) 166 { 167 struct netlink_sock *nlk = nlk_sk(sk); 168 169 if (nlk->cb) { 170 if (nlk->cb->done) 171 nlk->cb->done(nlk->cb); 172 netlink_destroy_callback(nlk->cb); 173 } 174 175 skb_queue_purge(&sk->sk_receive_queue); 176 177 if (!sock_flag(sk, SOCK_DEAD)) { 178 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk); 179 return; 180 } 181 182 WARN_ON(atomic_read(&sk->sk_rmem_alloc)); 183 WARN_ON(atomic_read(&sk->sk_wmem_alloc)); 184 WARN_ON(nlk_sk(sk)->groups); 185 } 186 187 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on 188 * SMP. Look, when several writers sleep and reader wakes them up, all but one 189 * immediately hit write lock and grab all the cpus. Exclusive sleep solves 190 * this, _but_ remember, it adds useless work on UP machines. 191 */ 192 193 void netlink_table_grab(void) 194 __acquires(nl_table_lock) 195 { 196 might_sleep(); 197 198 write_lock_irq(&nl_table_lock); 199 200 if (atomic_read(&nl_table_users)) { 201 DECLARE_WAITQUEUE(wait, current); 202 203 add_wait_queue_exclusive(&nl_table_wait, &wait); 204 for (;;) { 205 set_current_state(TASK_UNINTERRUPTIBLE); 206 if (atomic_read(&nl_table_users) == 0) 207 break; 208 write_unlock_irq(&nl_table_lock); 209 schedule(); 210 write_lock_irq(&nl_table_lock); 211 } 212 213 __set_current_state(TASK_RUNNING); 214 remove_wait_queue(&nl_table_wait, &wait); 215 } 216 } 217 218 void netlink_table_ungrab(void) 219 __releases(nl_table_lock) 220 { 221 write_unlock_irq(&nl_table_lock); 222 wake_up(&nl_table_wait); 223 } 224 225 static inline void 226 netlink_lock_table(void) 227 { 228 /* read_lock() synchronizes us to netlink_table_grab */ 229 230 read_lock(&nl_table_lock); 231 atomic_inc(&nl_table_users); 232 read_unlock(&nl_table_lock); 233 } 234 235 static inline void 236 netlink_unlock_table(void) 237 { 238 if (atomic_dec_and_test(&nl_table_users)) 239 wake_up(&nl_table_wait); 240 } 241 242 static struct sock *netlink_lookup(struct net *net, int protocol, u32 pid) 243 { 244 struct nl_pid_hash *hash = &nl_table[protocol].hash; 245 struct hlist_head *head; 246 struct sock *sk; 247 struct hlist_node *node; 248 249 read_lock(&nl_table_lock); 250 head = nl_pid_hashfn(hash, pid); 251 sk_for_each(sk, node, head) { 252 if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) { 253 sock_hold(sk); 254 goto found; 255 } 256 } 257 sk = NULL; 258 found: 259 read_unlock(&nl_table_lock); 260 return sk; 261 } 262 263 static struct hlist_head *nl_pid_hash_zalloc(size_t size) 264 { 265 if (size <= PAGE_SIZE) 266 return kzalloc(size, GFP_ATOMIC); 267 else 268 return (struct hlist_head *) 269 __get_free_pages(GFP_ATOMIC | __GFP_ZERO, 270 get_order(size)); 271 } 272 273 static void nl_pid_hash_free(struct hlist_head *table, size_t size) 274 { 275 if (size <= PAGE_SIZE) 276 kfree(table); 277 else 278 free_pages((unsigned long)table, get_order(size)); 279 } 280 281 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow) 282 { 283 unsigned int omask, mask, shift; 284 size_t osize, size; 285 struct hlist_head *otable, *table; 286 int i; 287 288 omask = mask = hash->mask; 289 osize = size = (mask + 1) * sizeof(*table); 290 shift = hash->shift; 291 292 if (grow) { 293 if (++shift > hash->max_shift) 294 return 0; 295 mask = mask * 2 + 1; 296 size *= 2; 297 } 298 299 table = nl_pid_hash_zalloc(size); 300 if (!table) 301 return 0; 302 303 otable = hash->table; 304 hash->table = table; 305 hash->mask = mask; 306 hash->shift = shift; 307 get_random_bytes(&hash->rnd, sizeof(hash->rnd)); 308 309 for (i = 0; i <= omask; i++) { 310 struct sock *sk; 311 struct hlist_node *node, *tmp; 312 313 sk_for_each_safe(sk, node, tmp, &otable[i]) 314 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid)); 315 } 316 317 nl_pid_hash_free(otable, osize); 318 hash->rehash_time = jiffies + 10 * 60 * HZ; 319 return 1; 320 } 321 322 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len) 323 { 324 int avg = hash->entries >> hash->shift; 325 326 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1)) 327 return 1; 328 329 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) { 330 nl_pid_hash_rehash(hash, 0); 331 return 1; 332 } 333 334 return 0; 335 } 336 337 static const struct proto_ops netlink_ops; 338 339 static void 340 netlink_update_listeners(struct sock *sk) 341 { 342 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 343 struct hlist_node *node; 344 unsigned long mask; 345 unsigned int i; 346 347 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) { 348 mask = 0; 349 sk_for_each_bound(sk, node, &tbl->mc_list) { 350 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups)) 351 mask |= nlk_sk(sk)->groups[i]; 352 } 353 tbl->listeners->masks[i] = mask; 354 } 355 /* this function is only called with the netlink table "grabbed", which 356 * makes sure updates are visible before bind or setsockopt return. */ 357 } 358 359 static int netlink_insert(struct sock *sk, struct net *net, u32 pid) 360 { 361 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 362 struct hlist_head *head; 363 int err = -EADDRINUSE; 364 struct sock *osk; 365 struct hlist_node *node; 366 int len; 367 368 netlink_table_grab(); 369 head = nl_pid_hashfn(hash, pid); 370 len = 0; 371 sk_for_each(osk, node, head) { 372 if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid)) 373 break; 374 len++; 375 } 376 if (node) 377 goto err; 378 379 err = -EBUSY; 380 if (nlk_sk(sk)->pid) 381 goto err; 382 383 err = -ENOMEM; 384 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX)) 385 goto err; 386 387 if (len && nl_pid_hash_dilute(hash, len)) 388 head = nl_pid_hashfn(hash, pid); 389 hash->entries++; 390 nlk_sk(sk)->pid = pid; 391 sk_add_node(sk, head); 392 err = 0; 393 394 err: 395 netlink_table_ungrab(); 396 return err; 397 } 398 399 static void netlink_remove(struct sock *sk) 400 { 401 netlink_table_grab(); 402 if (sk_del_node_init(sk)) 403 nl_table[sk->sk_protocol].hash.entries--; 404 if (nlk_sk(sk)->subscriptions) 405 __sk_del_bind_node(sk); 406 netlink_table_ungrab(); 407 } 408 409 static struct proto netlink_proto = { 410 .name = "NETLINK", 411 .owner = THIS_MODULE, 412 .obj_size = sizeof(struct netlink_sock), 413 }; 414 415 static int __netlink_create(struct net *net, struct socket *sock, 416 struct mutex *cb_mutex, int protocol) 417 { 418 struct sock *sk; 419 struct netlink_sock *nlk; 420 421 sock->ops = &netlink_ops; 422 423 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto); 424 if (!sk) 425 return -ENOMEM; 426 427 sock_init_data(sock, sk); 428 429 nlk = nlk_sk(sk); 430 if (cb_mutex) { 431 nlk->cb_mutex = cb_mutex; 432 } else { 433 nlk->cb_mutex = &nlk->cb_def_mutex; 434 mutex_init(nlk->cb_mutex); 435 } 436 init_waitqueue_head(&nlk->wait); 437 438 sk->sk_destruct = netlink_sock_destruct; 439 sk->sk_protocol = protocol; 440 return 0; 441 } 442 443 static int netlink_create(struct net *net, struct socket *sock, int protocol, 444 int kern) 445 { 446 struct module *module = NULL; 447 struct mutex *cb_mutex; 448 struct netlink_sock *nlk; 449 void (*bind)(int group); 450 int err = 0; 451 452 sock->state = SS_UNCONNECTED; 453 454 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) 455 return -ESOCKTNOSUPPORT; 456 457 if (protocol < 0 || protocol >= MAX_LINKS) 458 return -EPROTONOSUPPORT; 459 460 netlink_lock_table(); 461 #ifdef CONFIG_MODULES 462 if (!nl_table[protocol].registered) { 463 netlink_unlock_table(); 464 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); 465 netlink_lock_table(); 466 } 467 #endif 468 if (nl_table[protocol].registered && 469 try_module_get(nl_table[protocol].module)) 470 module = nl_table[protocol].module; 471 else 472 err = -EPROTONOSUPPORT; 473 cb_mutex = nl_table[protocol].cb_mutex; 474 bind = nl_table[protocol].bind; 475 netlink_unlock_table(); 476 477 if (err < 0) 478 goto out; 479 480 err = __netlink_create(net, sock, cb_mutex, protocol); 481 if (err < 0) 482 goto out_module; 483 484 local_bh_disable(); 485 sock_prot_inuse_add(net, &netlink_proto, 1); 486 local_bh_enable(); 487 488 nlk = nlk_sk(sock->sk); 489 nlk->module = module; 490 nlk->netlink_bind = bind; 491 out: 492 return err; 493 494 out_module: 495 module_put(module); 496 goto out; 497 } 498 499 static int netlink_release(struct socket *sock) 500 { 501 struct sock *sk = sock->sk; 502 struct netlink_sock *nlk; 503 504 if (!sk) 505 return 0; 506 507 netlink_remove(sk); 508 sock_orphan(sk); 509 nlk = nlk_sk(sk); 510 511 /* 512 * OK. Socket is unlinked, any packets that arrive now 513 * will be purged. 514 */ 515 516 sock->sk = NULL; 517 wake_up_interruptible_all(&nlk->wait); 518 519 skb_queue_purge(&sk->sk_write_queue); 520 521 if (nlk->pid) { 522 struct netlink_notify n = { 523 .net = sock_net(sk), 524 .protocol = sk->sk_protocol, 525 .pid = nlk->pid, 526 }; 527 atomic_notifier_call_chain(&netlink_chain, 528 NETLINK_URELEASE, &n); 529 } 530 531 module_put(nlk->module); 532 533 netlink_table_grab(); 534 if (netlink_is_kernel(sk)) { 535 BUG_ON(nl_table[sk->sk_protocol].registered == 0); 536 if (--nl_table[sk->sk_protocol].registered == 0) { 537 kfree(nl_table[sk->sk_protocol].listeners); 538 nl_table[sk->sk_protocol].module = NULL; 539 nl_table[sk->sk_protocol].registered = 0; 540 } 541 } else if (nlk->subscriptions) { 542 netlink_update_listeners(sk); 543 } 544 netlink_table_ungrab(); 545 546 kfree(nlk->groups); 547 nlk->groups = NULL; 548 549 local_bh_disable(); 550 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); 551 local_bh_enable(); 552 sock_put(sk); 553 return 0; 554 } 555 556 static int netlink_autobind(struct socket *sock) 557 { 558 struct sock *sk = sock->sk; 559 struct net *net = sock_net(sk); 560 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 561 struct hlist_head *head; 562 struct sock *osk; 563 struct hlist_node *node; 564 s32 pid = task_tgid_vnr(current); 565 int err; 566 static s32 rover = -4097; 567 568 retry: 569 cond_resched(); 570 netlink_table_grab(); 571 head = nl_pid_hashfn(hash, pid); 572 sk_for_each(osk, node, head) { 573 if (!net_eq(sock_net(osk), net)) 574 continue; 575 if (nlk_sk(osk)->pid == pid) { 576 /* Bind collision, search negative pid values. */ 577 pid = rover--; 578 if (rover > -4097) 579 rover = -4097; 580 netlink_table_ungrab(); 581 goto retry; 582 } 583 } 584 netlink_table_ungrab(); 585 586 err = netlink_insert(sk, net, pid); 587 if (err == -EADDRINUSE) 588 goto retry; 589 590 /* If 2 threads race to autobind, that is fine. */ 591 if (err == -EBUSY) 592 err = 0; 593 594 return err; 595 } 596 597 static inline int netlink_capable(const struct socket *sock, unsigned int flag) 598 { 599 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) || 600 capable(CAP_NET_ADMIN); 601 } 602 603 static void 604 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 605 { 606 struct netlink_sock *nlk = nlk_sk(sk); 607 608 if (nlk->subscriptions && !subscriptions) 609 __sk_del_bind_node(sk); 610 else if (!nlk->subscriptions && subscriptions) 611 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 612 nlk->subscriptions = subscriptions; 613 } 614 615 static int netlink_realloc_groups(struct sock *sk) 616 { 617 struct netlink_sock *nlk = nlk_sk(sk); 618 unsigned int groups; 619 unsigned long *new_groups; 620 int err = 0; 621 622 netlink_table_grab(); 623 624 groups = nl_table[sk->sk_protocol].groups; 625 if (!nl_table[sk->sk_protocol].registered) { 626 err = -ENOENT; 627 goto out_unlock; 628 } 629 630 if (nlk->ngroups >= groups) 631 goto out_unlock; 632 633 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC); 634 if (new_groups == NULL) { 635 err = -ENOMEM; 636 goto out_unlock; 637 } 638 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0, 639 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups)); 640 641 nlk->groups = new_groups; 642 nlk->ngroups = groups; 643 out_unlock: 644 netlink_table_ungrab(); 645 return err; 646 } 647 648 static int netlink_bind(struct socket *sock, struct sockaddr *addr, 649 int addr_len) 650 { 651 struct sock *sk = sock->sk; 652 struct net *net = sock_net(sk); 653 struct netlink_sock *nlk = nlk_sk(sk); 654 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 655 int err; 656 657 if (nladdr->nl_family != AF_NETLINK) 658 return -EINVAL; 659 660 /* Only superuser is allowed to listen multicasts */ 661 if (nladdr->nl_groups) { 662 if (!netlink_capable(sock, NL_NONROOT_RECV)) 663 return -EPERM; 664 err = netlink_realloc_groups(sk); 665 if (err) 666 return err; 667 } 668 669 if (nlk->pid) { 670 if (nladdr->nl_pid != nlk->pid) 671 return -EINVAL; 672 } else { 673 err = nladdr->nl_pid ? 674 netlink_insert(sk, net, nladdr->nl_pid) : 675 netlink_autobind(sock); 676 if (err) 677 return err; 678 } 679 680 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) 681 return 0; 682 683 netlink_table_grab(); 684 netlink_update_subscriptions(sk, nlk->subscriptions + 685 hweight32(nladdr->nl_groups) - 686 hweight32(nlk->groups[0])); 687 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups; 688 netlink_update_listeners(sk); 689 netlink_table_ungrab(); 690 691 if (nlk->netlink_bind && nlk->groups[0]) { 692 int i; 693 694 for (i=0; i<nlk->ngroups; i++) { 695 if (test_bit(i, nlk->groups)) 696 nlk->netlink_bind(i); 697 } 698 } 699 700 return 0; 701 } 702 703 static int netlink_connect(struct socket *sock, struct sockaddr *addr, 704 int alen, int flags) 705 { 706 int err = 0; 707 struct sock *sk = sock->sk; 708 struct netlink_sock *nlk = nlk_sk(sk); 709 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 710 711 if (alen < sizeof(addr->sa_family)) 712 return -EINVAL; 713 714 if (addr->sa_family == AF_UNSPEC) { 715 sk->sk_state = NETLINK_UNCONNECTED; 716 nlk->dst_pid = 0; 717 nlk->dst_group = 0; 718 return 0; 719 } 720 if (addr->sa_family != AF_NETLINK) 721 return -EINVAL; 722 723 /* Only superuser is allowed to send multicasts */ 724 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND)) 725 return -EPERM; 726 727 if (!nlk->pid) 728 err = netlink_autobind(sock); 729 730 if (err == 0) { 731 sk->sk_state = NETLINK_CONNECTED; 732 nlk->dst_pid = nladdr->nl_pid; 733 nlk->dst_group = ffs(nladdr->nl_groups); 734 } 735 736 return err; 737 } 738 739 static int netlink_getname(struct socket *sock, struct sockaddr *addr, 740 int *addr_len, int peer) 741 { 742 struct sock *sk = sock->sk; 743 struct netlink_sock *nlk = nlk_sk(sk); 744 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr); 745 746 nladdr->nl_family = AF_NETLINK; 747 nladdr->nl_pad = 0; 748 *addr_len = sizeof(*nladdr); 749 750 if (peer) { 751 nladdr->nl_pid = nlk->dst_pid; 752 nladdr->nl_groups = netlink_group_mask(nlk->dst_group); 753 } else { 754 nladdr->nl_pid = nlk->pid; 755 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 756 } 757 return 0; 758 } 759 760 static void netlink_overrun(struct sock *sk) 761 { 762 struct netlink_sock *nlk = nlk_sk(sk); 763 764 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) { 765 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) { 766 sk->sk_err = ENOBUFS; 767 sk->sk_error_report(sk); 768 } 769 } 770 atomic_inc(&sk->sk_drops); 771 } 772 773 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid) 774 { 775 struct sock *sock; 776 struct netlink_sock *nlk; 777 778 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid); 779 if (!sock) 780 return ERR_PTR(-ECONNREFUSED); 781 782 /* Don't bother queuing skb if kernel socket has no input function */ 783 nlk = nlk_sk(sock); 784 if (sock->sk_state == NETLINK_CONNECTED && 785 nlk->dst_pid != nlk_sk(ssk)->pid) { 786 sock_put(sock); 787 return ERR_PTR(-ECONNREFUSED); 788 } 789 return sock; 790 } 791 792 struct sock *netlink_getsockbyfilp(struct file *filp) 793 { 794 struct inode *inode = filp->f_path.dentry->d_inode; 795 struct sock *sock; 796 797 if (!S_ISSOCK(inode->i_mode)) 798 return ERR_PTR(-ENOTSOCK); 799 800 sock = SOCKET_I(inode)->sk; 801 if (sock->sk_family != AF_NETLINK) 802 return ERR_PTR(-EINVAL); 803 804 sock_hold(sock); 805 return sock; 806 } 807 808 /* 809 * Attach a skb to a netlink socket. 810 * The caller must hold a reference to the destination socket. On error, the 811 * reference is dropped. The skb is not send to the destination, just all 812 * all error checks are performed and memory in the queue is reserved. 813 * Return values: 814 * < 0: error. skb freed, reference to sock dropped. 815 * 0: continue 816 * 1: repeat lookup - reference dropped while waiting for socket memory. 817 */ 818 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, 819 long *timeo, struct sock *ssk) 820 { 821 struct netlink_sock *nlk; 822 823 nlk = nlk_sk(sk); 824 825 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 826 test_bit(0, &nlk->state)) { 827 DECLARE_WAITQUEUE(wait, current); 828 if (!*timeo) { 829 if (!ssk || netlink_is_kernel(ssk)) 830 netlink_overrun(sk); 831 sock_put(sk); 832 kfree_skb(skb); 833 return -EAGAIN; 834 } 835 836 __set_current_state(TASK_INTERRUPTIBLE); 837 add_wait_queue(&nlk->wait, &wait); 838 839 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 840 test_bit(0, &nlk->state)) && 841 !sock_flag(sk, SOCK_DEAD)) 842 *timeo = schedule_timeout(*timeo); 843 844 __set_current_state(TASK_RUNNING); 845 remove_wait_queue(&nlk->wait, &wait); 846 sock_put(sk); 847 848 if (signal_pending(current)) { 849 kfree_skb(skb); 850 return sock_intr_errno(*timeo); 851 } 852 return 1; 853 } 854 skb_set_owner_r(skb, sk); 855 return 0; 856 } 857 858 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) 859 { 860 int len = skb->len; 861 862 skb_queue_tail(&sk->sk_receive_queue, skb); 863 sk->sk_data_ready(sk, len); 864 return len; 865 } 866 867 int netlink_sendskb(struct sock *sk, struct sk_buff *skb) 868 { 869 int len = __netlink_sendskb(sk, skb); 870 871 sock_put(sk); 872 return len; 873 } 874 875 void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 876 { 877 kfree_skb(skb); 878 sock_put(sk); 879 } 880 881 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation) 882 { 883 int delta; 884 885 skb_orphan(skb); 886 887 delta = skb->end - skb->tail; 888 if (delta * 2 < skb->truesize) 889 return skb; 890 891 if (skb_shared(skb)) { 892 struct sk_buff *nskb = skb_clone(skb, allocation); 893 if (!nskb) 894 return skb; 895 consume_skb(skb); 896 skb = nskb; 897 } 898 899 if (!pskb_expand_head(skb, 0, -delta, allocation)) 900 skb->truesize -= delta; 901 902 return skb; 903 } 904 905 static void netlink_rcv_wake(struct sock *sk) 906 { 907 struct netlink_sock *nlk = nlk_sk(sk); 908 909 if (skb_queue_empty(&sk->sk_receive_queue)) 910 clear_bit(0, &nlk->state); 911 if (!test_bit(0, &nlk->state)) 912 wake_up_interruptible(&nlk->wait); 913 } 914 915 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb) 916 { 917 int ret; 918 struct netlink_sock *nlk = nlk_sk(sk); 919 920 ret = -ECONNREFUSED; 921 if (nlk->netlink_rcv != NULL) { 922 ret = skb->len; 923 skb_set_owner_r(skb, sk); 924 nlk->netlink_rcv(skb); 925 consume_skb(skb); 926 } else { 927 kfree_skb(skb); 928 } 929 sock_put(sk); 930 return ret; 931 } 932 933 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, 934 u32 pid, int nonblock) 935 { 936 struct sock *sk; 937 int err; 938 long timeo; 939 940 skb = netlink_trim(skb, gfp_any()); 941 942 timeo = sock_sndtimeo(ssk, nonblock); 943 retry: 944 sk = netlink_getsockbypid(ssk, pid); 945 if (IS_ERR(sk)) { 946 kfree_skb(skb); 947 return PTR_ERR(sk); 948 } 949 if (netlink_is_kernel(sk)) 950 return netlink_unicast_kernel(sk, skb); 951 952 if (sk_filter(sk, skb)) { 953 err = skb->len; 954 kfree_skb(skb); 955 sock_put(sk); 956 return err; 957 } 958 959 err = netlink_attachskb(sk, skb, &timeo, ssk); 960 if (err == 1) 961 goto retry; 962 if (err) 963 return err; 964 965 return netlink_sendskb(sk, skb); 966 } 967 EXPORT_SYMBOL(netlink_unicast); 968 969 int netlink_has_listeners(struct sock *sk, unsigned int group) 970 { 971 int res = 0; 972 struct listeners *listeners; 973 974 BUG_ON(!netlink_is_kernel(sk)); 975 976 rcu_read_lock(); 977 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners); 978 979 if (group - 1 < nl_table[sk->sk_protocol].groups) 980 res = test_bit(group - 1, listeners->masks); 981 982 rcu_read_unlock(); 983 984 return res; 985 } 986 EXPORT_SYMBOL_GPL(netlink_has_listeners); 987 988 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 989 { 990 struct netlink_sock *nlk = nlk_sk(sk); 991 992 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 993 !test_bit(0, &nlk->state)) { 994 skb_set_owner_r(skb, sk); 995 __netlink_sendskb(sk, skb); 996 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1); 997 } 998 return -1; 999 } 1000 1001 struct netlink_broadcast_data { 1002 struct sock *exclude_sk; 1003 struct net *net; 1004 u32 pid; 1005 u32 group; 1006 int failure; 1007 int delivery_failure; 1008 int congested; 1009 int delivered; 1010 gfp_t allocation; 1011 struct sk_buff *skb, *skb2; 1012 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data); 1013 void *tx_data; 1014 }; 1015 1016 static int do_one_broadcast(struct sock *sk, 1017 struct netlink_broadcast_data *p) 1018 { 1019 struct netlink_sock *nlk = nlk_sk(sk); 1020 int val; 1021 1022 if (p->exclude_sk == sk) 1023 goto out; 1024 1025 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 1026 !test_bit(p->group - 1, nlk->groups)) 1027 goto out; 1028 1029 if (!net_eq(sock_net(sk), p->net)) 1030 goto out; 1031 1032 if (p->failure) { 1033 netlink_overrun(sk); 1034 goto out; 1035 } 1036 1037 sock_hold(sk); 1038 if (p->skb2 == NULL) { 1039 if (skb_shared(p->skb)) { 1040 p->skb2 = skb_clone(p->skb, p->allocation); 1041 } else { 1042 p->skb2 = skb_get(p->skb); 1043 /* 1044 * skb ownership may have been set when 1045 * delivered to a previous socket. 1046 */ 1047 skb_orphan(p->skb2); 1048 } 1049 } 1050 if (p->skb2 == NULL) { 1051 netlink_overrun(sk); 1052 /* Clone failed. Notify ALL listeners. */ 1053 p->failure = 1; 1054 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR) 1055 p->delivery_failure = 1; 1056 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) { 1057 kfree_skb(p->skb2); 1058 p->skb2 = NULL; 1059 } else if (sk_filter(sk, p->skb2)) { 1060 kfree_skb(p->skb2); 1061 p->skb2 = NULL; 1062 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) { 1063 netlink_overrun(sk); 1064 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR) 1065 p->delivery_failure = 1; 1066 } else { 1067 p->congested |= val; 1068 p->delivered = 1; 1069 p->skb2 = NULL; 1070 } 1071 sock_put(sk); 1072 1073 out: 1074 return 0; 1075 } 1076 1077 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 pid, 1078 u32 group, gfp_t allocation, 1079 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data), 1080 void *filter_data) 1081 { 1082 struct net *net = sock_net(ssk); 1083 struct netlink_broadcast_data info; 1084 struct hlist_node *node; 1085 struct sock *sk; 1086 1087 skb = netlink_trim(skb, allocation); 1088 1089 info.exclude_sk = ssk; 1090 info.net = net; 1091 info.pid = pid; 1092 info.group = group; 1093 info.failure = 0; 1094 info.delivery_failure = 0; 1095 info.congested = 0; 1096 info.delivered = 0; 1097 info.allocation = allocation; 1098 info.skb = skb; 1099 info.skb2 = NULL; 1100 info.tx_filter = filter; 1101 info.tx_data = filter_data; 1102 1103 /* While we sleep in clone, do not allow to change socket list */ 1104 1105 netlink_lock_table(); 1106 1107 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 1108 do_one_broadcast(sk, &info); 1109 1110 consume_skb(skb); 1111 1112 netlink_unlock_table(); 1113 1114 if (info.delivery_failure) { 1115 kfree_skb(info.skb2); 1116 return -ENOBUFS; 1117 } 1118 consume_skb(info.skb2); 1119 1120 if (info.delivered) { 1121 if (info.congested && (allocation & __GFP_WAIT)) 1122 yield(); 1123 return 0; 1124 } 1125 return -ESRCH; 1126 } 1127 EXPORT_SYMBOL(netlink_broadcast_filtered); 1128 1129 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid, 1130 u32 group, gfp_t allocation) 1131 { 1132 return netlink_broadcast_filtered(ssk, skb, pid, group, allocation, 1133 NULL, NULL); 1134 } 1135 EXPORT_SYMBOL(netlink_broadcast); 1136 1137 struct netlink_set_err_data { 1138 struct sock *exclude_sk; 1139 u32 pid; 1140 u32 group; 1141 int code; 1142 }; 1143 1144 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p) 1145 { 1146 struct netlink_sock *nlk = nlk_sk(sk); 1147 int ret = 0; 1148 1149 if (sk == p->exclude_sk) 1150 goto out; 1151 1152 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk))) 1153 goto out; 1154 1155 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 1156 !test_bit(p->group - 1, nlk->groups)) 1157 goto out; 1158 1159 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) { 1160 ret = 1; 1161 goto out; 1162 } 1163 1164 sk->sk_err = p->code; 1165 sk->sk_error_report(sk); 1166 out: 1167 return ret; 1168 } 1169 1170 /** 1171 * netlink_set_err - report error to broadcast listeners 1172 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create() 1173 * @pid: the PID of a process that we want to skip (if any) 1174 * @groups: the broadcast group that will notice the error 1175 * @code: error code, must be negative (as usual in kernelspace) 1176 * 1177 * This function returns the number of broadcast listeners that have set the 1178 * NETLINK_RECV_NO_ENOBUFS socket option. 1179 */ 1180 int netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code) 1181 { 1182 struct netlink_set_err_data info; 1183 struct hlist_node *node; 1184 struct sock *sk; 1185 int ret = 0; 1186 1187 info.exclude_sk = ssk; 1188 info.pid = pid; 1189 info.group = group; 1190 /* sk->sk_err wants a positive error value */ 1191 info.code = -code; 1192 1193 read_lock(&nl_table_lock); 1194 1195 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 1196 ret += do_one_set_err(sk, &info); 1197 1198 read_unlock(&nl_table_lock); 1199 return ret; 1200 } 1201 EXPORT_SYMBOL(netlink_set_err); 1202 1203 /* must be called with netlink table grabbed */ 1204 static void netlink_update_socket_mc(struct netlink_sock *nlk, 1205 unsigned int group, 1206 int is_new) 1207 { 1208 int old, new = !!is_new, subscriptions; 1209 1210 old = test_bit(group - 1, nlk->groups); 1211 subscriptions = nlk->subscriptions - old + new; 1212 if (new) 1213 __set_bit(group - 1, nlk->groups); 1214 else 1215 __clear_bit(group - 1, nlk->groups); 1216 netlink_update_subscriptions(&nlk->sk, subscriptions); 1217 netlink_update_listeners(&nlk->sk); 1218 } 1219 1220 static int netlink_setsockopt(struct socket *sock, int level, int optname, 1221 char __user *optval, unsigned int optlen) 1222 { 1223 struct sock *sk = sock->sk; 1224 struct netlink_sock *nlk = nlk_sk(sk); 1225 unsigned int val = 0; 1226 int err; 1227 1228 if (level != SOL_NETLINK) 1229 return -ENOPROTOOPT; 1230 1231 if (optlen >= sizeof(int) && 1232 get_user(val, (unsigned int __user *)optval)) 1233 return -EFAULT; 1234 1235 switch (optname) { 1236 case NETLINK_PKTINFO: 1237 if (val) 1238 nlk->flags |= NETLINK_RECV_PKTINFO; 1239 else 1240 nlk->flags &= ~NETLINK_RECV_PKTINFO; 1241 err = 0; 1242 break; 1243 case NETLINK_ADD_MEMBERSHIP: 1244 case NETLINK_DROP_MEMBERSHIP: { 1245 if (!netlink_capable(sock, NL_NONROOT_RECV)) 1246 return -EPERM; 1247 err = netlink_realloc_groups(sk); 1248 if (err) 1249 return err; 1250 if (!val || val - 1 >= nlk->ngroups) 1251 return -EINVAL; 1252 netlink_table_grab(); 1253 netlink_update_socket_mc(nlk, val, 1254 optname == NETLINK_ADD_MEMBERSHIP); 1255 netlink_table_ungrab(); 1256 1257 if (nlk->netlink_bind) 1258 nlk->netlink_bind(val); 1259 1260 err = 0; 1261 break; 1262 } 1263 case NETLINK_BROADCAST_ERROR: 1264 if (val) 1265 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR; 1266 else 1267 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR; 1268 err = 0; 1269 break; 1270 case NETLINK_NO_ENOBUFS: 1271 if (val) { 1272 nlk->flags |= NETLINK_RECV_NO_ENOBUFS; 1273 clear_bit(0, &nlk->state); 1274 wake_up_interruptible(&nlk->wait); 1275 } else { 1276 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS; 1277 } 1278 err = 0; 1279 break; 1280 default: 1281 err = -ENOPROTOOPT; 1282 } 1283 return err; 1284 } 1285 1286 static int netlink_getsockopt(struct socket *sock, int level, int optname, 1287 char __user *optval, int __user *optlen) 1288 { 1289 struct sock *sk = sock->sk; 1290 struct netlink_sock *nlk = nlk_sk(sk); 1291 int len, val, err; 1292 1293 if (level != SOL_NETLINK) 1294 return -ENOPROTOOPT; 1295 1296 if (get_user(len, optlen)) 1297 return -EFAULT; 1298 if (len < 0) 1299 return -EINVAL; 1300 1301 switch (optname) { 1302 case NETLINK_PKTINFO: 1303 if (len < sizeof(int)) 1304 return -EINVAL; 1305 len = sizeof(int); 1306 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0; 1307 if (put_user(len, optlen) || 1308 put_user(val, optval)) 1309 return -EFAULT; 1310 err = 0; 1311 break; 1312 case NETLINK_BROADCAST_ERROR: 1313 if (len < sizeof(int)) 1314 return -EINVAL; 1315 len = sizeof(int); 1316 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0; 1317 if (put_user(len, optlen) || 1318 put_user(val, optval)) 1319 return -EFAULT; 1320 err = 0; 1321 break; 1322 case NETLINK_NO_ENOBUFS: 1323 if (len < sizeof(int)) 1324 return -EINVAL; 1325 len = sizeof(int); 1326 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0; 1327 if (put_user(len, optlen) || 1328 put_user(val, optval)) 1329 return -EFAULT; 1330 err = 0; 1331 break; 1332 default: 1333 err = -ENOPROTOOPT; 1334 } 1335 return err; 1336 } 1337 1338 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1339 { 1340 struct nl_pktinfo info; 1341 1342 info.group = NETLINK_CB(skb).dst_group; 1343 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1344 } 1345 1346 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock, 1347 struct msghdr *msg, size_t len) 1348 { 1349 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1350 struct sock *sk = sock->sk; 1351 struct netlink_sock *nlk = nlk_sk(sk); 1352 struct sockaddr_nl *addr = msg->msg_name; 1353 u32 dst_pid; 1354 u32 dst_group; 1355 struct sk_buff *skb; 1356 int err; 1357 struct scm_cookie scm; 1358 1359 if (msg->msg_flags&MSG_OOB) 1360 return -EOPNOTSUPP; 1361 1362 if (NULL == siocb->scm) 1363 siocb->scm = &scm; 1364 1365 err = scm_send(sock, msg, siocb->scm, true); 1366 if (err < 0) 1367 return err; 1368 1369 if (msg->msg_namelen) { 1370 err = -EINVAL; 1371 if (addr->nl_family != AF_NETLINK) 1372 goto out; 1373 dst_pid = addr->nl_pid; 1374 dst_group = ffs(addr->nl_groups); 1375 err = -EPERM; 1376 if ((dst_group || dst_pid) && 1377 !netlink_capable(sock, NL_NONROOT_SEND)) 1378 goto out; 1379 } else { 1380 dst_pid = nlk->dst_pid; 1381 dst_group = nlk->dst_group; 1382 } 1383 1384 if (!nlk->pid) { 1385 err = netlink_autobind(sock); 1386 if (err) 1387 goto out; 1388 } 1389 1390 err = -EMSGSIZE; 1391 if (len > sk->sk_sndbuf - 32) 1392 goto out; 1393 err = -ENOBUFS; 1394 skb = alloc_skb(len, GFP_KERNEL); 1395 if (skb == NULL) 1396 goto out; 1397 1398 NETLINK_CB(skb).pid = nlk->pid; 1399 NETLINK_CB(skb).dst_group = dst_group; 1400 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1401 1402 err = -EFAULT; 1403 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) { 1404 kfree_skb(skb); 1405 goto out; 1406 } 1407 1408 err = security_netlink_send(sk, skb); 1409 if (err) { 1410 kfree_skb(skb); 1411 goto out; 1412 } 1413 1414 if (dst_group) { 1415 atomic_inc(&skb->users); 1416 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL); 1417 } 1418 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT); 1419 1420 out: 1421 scm_destroy(siocb->scm); 1422 return err; 1423 } 1424 1425 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, 1426 struct msghdr *msg, size_t len, 1427 int flags) 1428 { 1429 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1430 struct scm_cookie scm; 1431 struct sock *sk = sock->sk; 1432 struct netlink_sock *nlk = nlk_sk(sk); 1433 int noblock = flags&MSG_DONTWAIT; 1434 size_t copied; 1435 struct sk_buff *skb, *data_skb; 1436 int err, ret; 1437 1438 if (flags&MSG_OOB) 1439 return -EOPNOTSUPP; 1440 1441 copied = 0; 1442 1443 skb = skb_recv_datagram(sk, flags, noblock, &err); 1444 if (skb == NULL) 1445 goto out; 1446 1447 data_skb = skb; 1448 1449 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES 1450 if (unlikely(skb_shinfo(skb)->frag_list)) { 1451 /* 1452 * If this skb has a frag_list, then here that means that we 1453 * will have to use the frag_list skb's data for compat tasks 1454 * and the regular skb's data for normal (non-compat) tasks. 1455 * 1456 * If we need to send the compat skb, assign it to the 1457 * 'data_skb' variable so that it will be used below for data 1458 * copying. We keep 'skb' for everything else, including 1459 * freeing both later. 1460 */ 1461 if (flags & MSG_CMSG_COMPAT) 1462 data_skb = skb_shinfo(skb)->frag_list; 1463 } 1464 #endif 1465 1466 msg->msg_namelen = 0; 1467 1468 copied = data_skb->len; 1469 if (len < copied) { 1470 msg->msg_flags |= MSG_TRUNC; 1471 copied = len; 1472 } 1473 1474 skb_reset_transport_header(data_skb); 1475 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied); 1476 1477 if (msg->msg_name) { 1478 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name; 1479 addr->nl_family = AF_NETLINK; 1480 addr->nl_pad = 0; 1481 addr->nl_pid = NETLINK_CB(skb).pid; 1482 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1483 msg->msg_namelen = sizeof(*addr); 1484 } 1485 1486 if (nlk->flags & NETLINK_RECV_PKTINFO) 1487 netlink_cmsg_recv_pktinfo(msg, skb); 1488 1489 if (NULL == siocb->scm) { 1490 memset(&scm, 0, sizeof(scm)); 1491 siocb->scm = &scm; 1492 } 1493 siocb->scm->creds = *NETLINK_CREDS(skb); 1494 if (flags & MSG_TRUNC) 1495 copied = data_skb->len; 1496 1497 skb_free_datagram(sk, skb); 1498 1499 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { 1500 ret = netlink_dump(sk); 1501 if (ret) { 1502 sk->sk_err = ret; 1503 sk->sk_error_report(sk); 1504 } 1505 } 1506 1507 scm_recv(sock, msg, siocb->scm, flags); 1508 out: 1509 netlink_rcv_wake(sk); 1510 return err ? : copied; 1511 } 1512 1513 static void netlink_data_ready(struct sock *sk, int len) 1514 { 1515 BUG(); 1516 } 1517 1518 /* 1519 * We export these functions to other modules. They provide a 1520 * complete set of kernel non-blocking support for message 1521 * queueing. 1522 */ 1523 1524 struct sock * 1525 netlink_kernel_create(struct net *net, int unit, 1526 struct module *module, 1527 struct netlink_kernel_cfg *cfg) 1528 { 1529 struct socket *sock; 1530 struct sock *sk; 1531 struct netlink_sock *nlk; 1532 struct listeners *listeners = NULL; 1533 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL; 1534 unsigned int groups; 1535 1536 BUG_ON(!nl_table); 1537 1538 if (unit < 0 || unit >= MAX_LINKS) 1539 return NULL; 1540 1541 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 1542 return NULL; 1543 1544 /* 1545 * We have to just have a reference on the net from sk, but don't 1546 * get_net it. Besides, we cannot get and then put the net here. 1547 * So we create one inside init_net and the move it to net. 1548 */ 1549 1550 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0) 1551 goto out_sock_release_nosk; 1552 1553 sk = sock->sk; 1554 sk_change_net(sk, net); 1555 1556 if (!cfg || cfg->groups < 32) 1557 groups = 32; 1558 else 1559 groups = cfg->groups; 1560 1561 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 1562 if (!listeners) 1563 goto out_sock_release; 1564 1565 sk->sk_data_ready = netlink_data_ready; 1566 if (cfg && cfg->input) 1567 nlk_sk(sk)->netlink_rcv = cfg->input; 1568 1569 if (netlink_insert(sk, net, 0)) 1570 goto out_sock_release; 1571 1572 nlk = nlk_sk(sk); 1573 nlk->flags |= NETLINK_KERNEL_SOCKET; 1574 1575 netlink_table_grab(); 1576 if (!nl_table[unit].registered) { 1577 nl_table[unit].groups = groups; 1578 rcu_assign_pointer(nl_table[unit].listeners, listeners); 1579 nl_table[unit].cb_mutex = cb_mutex; 1580 nl_table[unit].module = module; 1581 nl_table[unit].bind = cfg ? cfg->bind : NULL; 1582 nl_table[unit].registered = 1; 1583 } else { 1584 kfree(listeners); 1585 nl_table[unit].registered++; 1586 } 1587 netlink_table_ungrab(); 1588 return sk; 1589 1590 out_sock_release: 1591 kfree(listeners); 1592 netlink_kernel_release(sk); 1593 return NULL; 1594 1595 out_sock_release_nosk: 1596 sock_release(sock); 1597 return NULL; 1598 } 1599 EXPORT_SYMBOL(netlink_kernel_create); 1600 1601 1602 void 1603 netlink_kernel_release(struct sock *sk) 1604 { 1605 sk_release_kernel(sk); 1606 } 1607 EXPORT_SYMBOL(netlink_kernel_release); 1608 1609 int __netlink_change_ngroups(struct sock *sk, unsigned int groups) 1610 { 1611 struct listeners *new, *old; 1612 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 1613 1614 if (groups < 32) 1615 groups = 32; 1616 1617 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { 1618 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); 1619 if (!new) 1620 return -ENOMEM; 1621 old = rcu_dereference_protected(tbl->listeners, 1); 1622 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); 1623 rcu_assign_pointer(tbl->listeners, new); 1624 1625 kfree_rcu(old, rcu); 1626 } 1627 tbl->groups = groups; 1628 1629 return 0; 1630 } 1631 1632 /** 1633 * netlink_change_ngroups - change number of multicast groups 1634 * 1635 * This changes the number of multicast groups that are available 1636 * on a certain netlink family. Note that it is not possible to 1637 * change the number of groups to below 32. Also note that it does 1638 * not implicitly call netlink_clear_multicast_users() when the 1639 * number of groups is reduced. 1640 * 1641 * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). 1642 * @groups: The new number of groups. 1643 */ 1644 int netlink_change_ngroups(struct sock *sk, unsigned int groups) 1645 { 1646 int err; 1647 1648 netlink_table_grab(); 1649 err = __netlink_change_ngroups(sk, groups); 1650 netlink_table_ungrab(); 1651 1652 return err; 1653 } 1654 1655 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) 1656 { 1657 struct sock *sk; 1658 struct hlist_node *node; 1659 struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; 1660 1661 sk_for_each_bound(sk, node, &tbl->mc_list) 1662 netlink_update_socket_mc(nlk_sk(sk), group, 0); 1663 } 1664 1665 /** 1666 * netlink_clear_multicast_users - kick off multicast listeners 1667 * 1668 * This function removes all listeners from the given group. 1669 * @ksk: The kernel netlink socket, as returned by 1670 * netlink_kernel_create(). 1671 * @group: The multicast group to clear. 1672 */ 1673 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group) 1674 { 1675 netlink_table_grab(); 1676 __netlink_clear_multicast_users(ksk, group); 1677 netlink_table_ungrab(); 1678 } 1679 1680 void netlink_set_nonroot(int protocol, unsigned int flags) 1681 { 1682 if ((unsigned int)protocol < MAX_LINKS) 1683 nl_table[protocol].nl_nonroot = flags; 1684 } 1685 EXPORT_SYMBOL(netlink_set_nonroot); 1686 1687 struct nlmsghdr * 1688 __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags) 1689 { 1690 struct nlmsghdr *nlh; 1691 int size = NLMSG_LENGTH(len); 1692 1693 nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size)); 1694 nlh->nlmsg_type = type; 1695 nlh->nlmsg_len = size; 1696 nlh->nlmsg_flags = flags; 1697 nlh->nlmsg_pid = pid; 1698 nlh->nlmsg_seq = seq; 1699 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) 1700 memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size); 1701 return nlh; 1702 } 1703 EXPORT_SYMBOL(__nlmsg_put); 1704 1705 /* 1706 * It looks a bit ugly. 1707 * It would be better to create kernel thread. 1708 */ 1709 1710 static int netlink_dump(struct sock *sk) 1711 { 1712 struct netlink_sock *nlk = nlk_sk(sk); 1713 struct netlink_callback *cb; 1714 struct sk_buff *skb = NULL; 1715 struct nlmsghdr *nlh; 1716 int len, err = -ENOBUFS; 1717 int alloc_size; 1718 1719 mutex_lock(nlk->cb_mutex); 1720 1721 cb = nlk->cb; 1722 if (cb == NULL) { 1723 err = -EINVAL; 1724 goto errout_skb; 1725 } 1726 1727 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); 1728 1729 skb = sock_rmalloc(sk, alloc_size, 0, GFP_KERNEL); 1730 if (!skb) 1731 goto errout_skb; 1732 1733 len = cb->dump(skb, cb); 1734 1735 if (len > 0) { 1736 mutex_unlock(nlk->cb_mutex); 1737 1738 if (sk_filter(sk, skb)) 1739 kfree_skb(skb); 1740 else 1741 __netlink_sendskb(sk, skb); 1742 return 0; 1743 } 1744 1745 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); 1746 if (!nlh) 1747 goto errout_skb; 1748 1749 nl_dump_check_consistent(cb, nlh); 1750 1751 memcpy(nlmsg_data(nlh), &len, sizeof(len)); 1752 1753 if (sk_filter(sk, skb)) 1754 kfree_skb(skb); 1755 else 1756 __netlink_sendskb(sk, skb); 1757 1758 if (cb->done) 1759 cb->done(cb); 1760 nlk->cb = NULL; 1761 mutex_unlock(nlk->cb_mutex); 1762 1763 netlink_consume_callback(cb); 1764 return 0; 1765 1766 errout_skb: 1767 mutex_unlock(nlk->cb_mutex); 1768 kfree_skb(skb); 1769 return err; 1770 } 1771 1772 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 1773 const struct nlmsghdr *nlh, 1774 struct netlink_dump_control *control) 1775 { 1776 struct netlink_callback *cb; 1777 struct sock *sk; 1778 struct netlink_sock *nlk; 1779 int ret; 1780 1781 cb = kzalloc(sizeof(*cb), GFP_KERNEL); 1782 if (cb == NULL) 1783 return -ENOBUFS; 1784 1785 cb->dump = control->dump; 1786 cb->done = control->done; 1787 cb->nlh = nlh; 1788 cb->data = control->data; 1789 cb->min_dump_alloc = control->min_dump_alloc; 1790 atomic_inc(&skb->users); 1791 cb->skb = skb; 1792 1793 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid); 1794 if (sk == NULL) { 1795 netlink_destroy_callback(cb); 1796 return -ECONNREFUSED; 1797 } 1798 nlk = nlk_sk(sk); 1799 /* A dump is in progress... */ 1800 mutex_lock(nlk->cb_mutex); 1801 if (nlk->cb) { 1802 mutex_unlock(nlk->cb_mutex); 1803 netlink_destroy_callback(cb); 1804 sock_put(sk); 1805 return -EBUSY; 1806 } 1807 nlk->cb = cb; 1808 mutex_unlock(nlk->cb_mutex); 1809 1810 ret = netlink_dump(sk); 1811 1812 sock_put(sk); 1813 1814 if (ret) 1815 return ret; 1816 1817 /* We successfully started a dump, by returning -EINTR we 1818 * signal not to send ACK even if it was requested. 1819 */ 1820 return -EINTR; 1821 } 1822 EXPORT_SYMBOL(netlink_dump_start); 1823 1824 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) 1825 { 1826 struct sk_buff *skb; 1827 struct nlmsghdr *rep; 1828 struct nlmsgerr *errmsg; 1829 size_t payload = sizeof(*errmsg); 1830 1831 /* error messages get the original request appened */ 1832 if (err) 1833 payload += nlmsg_len(nlh); 1834 1835 skb = nlmsg_new(payload, GFP_KERNEL); 1836 if (!skb) { 1837 struct sock *sk; 1838 1839 sk = netlink_lookup(sock_net(in_skb->sk), 1840 in_skb->sk->sk_protocol, 1841 NETLINK_CB(in_skb).pid); 1842 if (sk) { 1843 sk->sk_err = ENOBUFS; 1844 sk->sk_error_report(sk); 1845 sock_put(sk); 1846 } 1847 return; 1848 } 1849 1850 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, 1851 NLMSG_ERROR, payload, 0); 1852 errmsg = nlmsg_data(rep); 1853 errmsg->error = err; 1854 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh)); 1855 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT); 1856 } 1857 EXPORT_SYMBOL(netlink_ack); 1858 1859 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 1860 struct nlmsghdr *)) 1861 { 1862 struct nlmsghdr *nlh; 1863 int err; 1864 1865 while (skb->len >= nlmsg_total_size(0)) { 1866 int msglen; 1867 1868 nlh = nlmsg_hdr(skb); 1869 err = 0; 1870 1871 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 1872 return 0; 1873 1874 /* Only requests are handled by the kernel */ 1875 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) 1876 goto ack; 1877 1878 /* Skip control messages */ 1879 if (nlh->nlmsg_type < NLMSG_MIN_TYPE) 1880 goto ack; 1881 1882 err = cb(skb, nlh); 1883 if (err == -EINTR) 1884 goto skip; 1885 1886 ack: 1887 if (nlh->nlmsg_flags & NLM_F_ACK || err) 1888 netlink_ack(skb, nlh, err); 1889 1890 skip: 1891 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 1892 if (msglen > skb->len) 1893 msglen = skb->len; 1894 skb_pull(skb, msglen); 1895 } 1896 1897 return 0; 1898 } 1899 EXPORT_SYMBOL(netlink_rcv_skb); 1900 1901 /** 1902 * nlmsg_notify - send a notification netlink message 1903 * @sk: netlink socket to use 1904 * @skb: notification message 1905 * @pid: destination netlink pid for reports or 0 1906 * @group: destination multicast group or 0 1907 * @report: 1 to report back, 0 to disable 1908 * @flags: allocation flags 1909 */ 1910 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid, 1911 unsigned int group, int report, gfp_t flags) 1912 { 1913 int err = 0; 1914 1915 if (group) { 1916 int exclude_pid = 0; 1917 1918 if (report) { 1919 atomic_inc(&skb->users); 1920 exclude_pid = pid; 1921 } 1922 1923 /* errors reported via destination sk->sk_err, but propagate 1924 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ 1925 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags); 1926 } 1927 1928 if (report) { 1929 int err2; 1930 1931 err2 = nlmsg_unicast(sk, skb, pid); 1932 if (!err || err == -ESRCH) 1933 err = err2; 1934 } 1935 1936 return err; 1937 } 1938 EXPORT_SYMBOL(nlmsg_notify); 1939 1940 #ifdef CONFIG_PROC_FS 1941 struct nl_seq_iter { 1942 struct seq_net_private p; 1943 int link; 1944 int hash_idx; 1945 }; 1946 1947 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos) 1948 { 1949 struct nl_seq_iter *iter = seq->private; 1950 int i, j; 1951 struct sock *s; 1952 struct hlist_node *node; 1953 loff_t off = 0; 1954 1955 for (i = 0; i < MAX_LINKS; i++) { 1956 struct nl_pid_hash *hash = &nl_table[i].hash; 1957 1958 for (j = 0; j <= hash->mask; j++) { 1959 sk_for_each(s, node, &hash->table[j]) { 1960 if (sock_net(s) != seq_file_net(seq)) 1961 continue; 1962 if (off == pos) { 1963 iter->link = i; 1964 iter->hash_idx = j; 1965 return s; 1966 } 1967 ++off; 1968 } 1969 } 1970 } 1971 return NULL; 1972 } 1973 1974 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos) 1975 __acquires(nl_table_lock) 1976 { 1977 read_lock(&nl_table_lock); 1978 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN; 1979 } 1980 1981 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1982 { 1983 struct sock *s; 1984 struct nl_seq_iter *iter; 1985 int i, j; 1986 1987 ++*pos; 1988 1989 if (v == SEQ_START_TOKEN) 1990 return netlink_seq_socket_idx(seq, 0); 1991 1992 iter = seq->private; 1993 s = v; 1994 do { 1995 s = sk_next(s); 1996 } while (s && sock_net(s) != seq_file_net(seq)); 1997 if (s) 1998 return s; 1999 2000 i = iter->link; 2001 j = iter->hash_idx + 1; 2002 2003 do { 2004 struct nl_pid_hash *hash = &nl_table[i].hash; 2005 2006 for (; j <= hash->mask; j++) { 2007 s = sk_head(&hash->table[j]); 2008 while (s && sock_net(s) != seq_file_net(seq)) 2009 s = sk_next(s); 2010 if (s) { 2011 iter->link = i; 2012 iter->hash_idx = j; 2013 return s; 2014 } 2015 } 2016 2017 j = 0; 2018 } while (++i < MAX_LINKS); 2019 2020 return NULL; 2021 } 2022 2023 static void netlink_seq_stop(struct seq_file *seq, void *v) 2024 __releases(nl_table_lock) 2025 { 2026 read_unlock(&nl_table_lock); 2027 } 2028 2029 2030 static int netlink_seq_show(struct seq_file *seq, void *v) 2031 { 2032 if (v == SEQ_START_TOKEN) { 2033 seq_puts(seq, 2034 "sk Eth Pid Groups " 2035 "Rmem Wmem Dump Locks Drops Inode\n"); 2036 } else { 2037 struct sock *s = v; 2038 struct netlink_sock *nlk = nlk_sk(s); 2039 2040 seq_printf(seq, "%pK %-3d %-6d %08x %-8d %-8d %pK %-8d %-8d %-8lu\n", 2041 s, 2042 s->sk_protocol, 2043 nlk->pid, 2044 nlk->groups ? (u32)nlk->groups[0] : 0, 2045 sk_rmem_alloc_get(s), 2046 sk_wmem_alloc_get(s), 2047 nlk->cb, 2048 atomic_read(&s->sk_refcnt), 2049 atomic_read(&s->sk_drops), 2050 sock_i_ino(s) 2051 ); 2052 2053 } 2054 return 0; 2055 } 2056 2057 static const struct seq_operations netlink_seq_ops = { 2058 .start = netlink_seq_start, 2059 .next = netlink_seq_next, 2060 .stop = netlink_seq_stop, 2061 .show = netlink_seq_show, 2062 }; 2063 2064 2065 static int netlink_seq_open(struct inode *inode, struct file *file) 2066 { 2067 return seq_open_net(inode, file, &netlink_seq_ops, 2068 sizeof(struct nl_seq_iter)); 2069 } 2070 2071 static const struct file_operations netlink_seq_fops = { 2072 .owner = THIS_MODULE, 2073 .open = netlink_seq_open, 2074 .read = seq_read, 2075 .llseek = seq_lseek, 2076 .release = seq_release_net, 2077 }; 2078 2079 #endif 2080 2081 int netlink_register_notifier(struct notifier_block *nb) 2082 { 2083 return atomic_notifier_chain_register(&netlink_chain, nb); 2084 } 2085 EXPORT_SYMBOL(netlink_register_notifier); 2086 2087 int netlink_unregister_notifier(struct notifier_block *nb) 2088 { 2089 return atomic_notifier_chain_unregister(&netlink_chain, nb); 2090 } 2091 EXPORT_SYMBOL(netlink_unregister_notifier); 2092 2093 static const struct proto_ops netlink_ops = { 2094 .family = PF_NETLINK, 2095 .owner = THIS_MODULE, 2096 .release = netlink_release, 2097 .bind = netlink_bind, 2098 .connect = netlink_connect, 2099 .socketpair = sock_no_socketpair, 2100 .accept = sock_no_accept, 2101 .getname = netlink_getname, 2102 .poll = datagram_poll, 2103 .ioctl = sock_no_ioctl, 2104 .listen = sock_no_listen, 2105 .shutdown = sock_no_shutdown, 2106 .setsockopt = netlink_setsockopt, 2107 .getsockopt = netlink_getsockopt, 2108 .sendmsg = netlink_sendmsg, 2109 .recvmsg = netlink_recvmsg, 2110 .mmap = sock_no_mmap, 2111 .sendpage = sock_no_sendpage, 2112 }; 2113 2114 static const struct net_proto_family netlink_family_ops = { 2115 .family = PF_NETLINK, 2116 .create = netlink_create, 2117 .owner = THIS_MODULE, /* for consistency 8) */ 2118 }; 2119 2120 static int __net_init netlink_net_init(struct net *net) 2121 { 2122 #ifdef CONFIG_PROC_FS 2123 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops)) 2124 return -ENOMEM; 2125 #endif 2126 return 0; 2127 } 2128 2129 static void __net_exit netlink_net_exit(struct net *net) 2130 { 2131 #ifdef CONFIG_PROC_FS 2132 proc_net_remove(net, "netlink"); 2133 #endif 2134 } 2135 2136 static void __init netlink_add_usersock_entry(void) 2137 { 2138 struct listeners *listeners; 2139 int groups = 32; 2140 2141 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2142 if (!listeners) 2143 panic("netlink_add_usersock_entry: Cannot allocate listeners\n"); 2144 2145 netlink_table_grab(); 2146 2147 nl_table[NETLINK_USERSOCK].groups = groups; 2148 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners); 2149 nl_table[NETLINK_USERSOCK].module = THIS_MODULE; 2150 nl_table[NETLINK_USERSOCK].registered = 1; 2151 nl_table[NETLINK_USERSOCK].nl_nonroot = NL_NONROOT_SEND; 2152 2153 netlink_table_ungrab(); 2154 } 2155 2156 static struct pernet_operations __net_initdata netlink_net_ops = { 2157 .init = netlink_net_init, 2158 .exit = netlink_net_exit, 2159 }; 2160 2161 static int __init netlink_proto_init(void) 2162 { 2163 struct sk_buff *dummy_skb; 2164 int i; 2165 unsigned long limit; 2166 unsigned int order; 2167 int err = proto_register(&netlink_proto, 0); 2168 2169 if (err != 0) 2170 goto out; 2171 2172 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb)); 2173 2174 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 2175 if (!nl_table) 2176 goto panic; 2177 2178 if (totalram_pages >= (128 * 1024)) 2179 limit = totalram_pages >> (21 - PAGE_SHIFT); 2180 else 2181 limit = totalram_pages >> (23 - PAGE_SHIFT); 2182 2183 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT; 2184 limit = (1UL << order) / sizeof(struct hlist_head); 2185 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1; 2186 2187 for (i = 0; i < MAX_LINKS; i++) { 2188 struct nl_pid_hash *hash = &nl_table[i].hash; 2189 2190 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table)); 2191 if (!hash->table) { 2192 while (i-- > 0) 2193 nl_pid_hash_free(nl_table[i].hash.table, 2194 1 * sizeof(*hash->table)); 2195 kfree(nl_table); 2196 goto panic; 2197 } 2198 hash->max_shift = order; 2199 hash->shift = 0; 2200 hash->mask = 0; 2201 hash->rehash_time = jiffies; 2202 } 2203 2204 netlink_add_usersock_entry(); 2205 2206 sock_register(&netlink_family_ops); 2207 register_pernet_subsys(&netlink_net_ops); 2208 /* The netlink device handler may be needed early. */ 2209 rtnetlink_init(); 2210 out: 2211 return err; 2212 panic: 2213 panic("netlink_init: Cannot allocate nl_table\n"); 2214 } 2215 2216 core_initcall(netlink_proto_init); 2217