1 /* 2 * NETLINK Kernel-user communication protocol. 3 * 4 * Authors: Alan Cox <alan@redhat.com> 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/smp_lock.h> 49 #include <linux/notifier.h> 50 #include <linux/security.h> 51 #include <linux/jhash.h> 52 #include <linux/jiffies.h> 53 #include <linux/random.h> 54 #include <linux/bitops.h> 55 #include <linux/mm.h> 56 #include <linux/types.h> 57 #include <linux/audit.h> 58 #include <linux/selinux.h> 59 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 66 struct netlink_sock { 67 /* struct sock has to be the first member of netlink_sock */ 68 struct sock sk; 69 u32 pid; 70 u32 dst_pid; 71 u32 dst_group; 72 u32 flags; 73 u32 subscriptions; 74 u32 ngroups; 75 unsigned long *groups; 76 unsigned long state; 77 wait_queue_head_t wait; 78 struct netlink_callback *cb; 79 spinlock_t cb_lock; 80 void (*data_ready)(struct sock *sk, int bytes); 81 struct module *module; 82 }; 83 84 #define NETLINK_KERNEL_SOCKET 0x1 85 #define NETLINK_RECV_PKTINFO 0x2 86 87 static inline struct netlink_sock *nlk_sk(struct sock *sk) 88 { 89 return (struct netlink_sock *)sk; 90 } 91 92 struct nl_pid_hash { 93 struct hlist_head *table; 94 unsigned long rehash_time; 95 96 unsigned int mask; 97 unsigned int shift; 98 99 unsigned int entries; 100 unsigned int max_shift; 101 102 u32 rnd; 103 }; 104 105 struct netlink_table { 106 struct nl_pid_hash hash; 107 struct hlist_head mc_list; 108 unsigned long *listeners; 109 unsigned int nl_nonroot; 110 unsigned int groups; 111 struct module *module; 112 int registered; 113 }; 114 115 static struct netlink_table *nl_table; 116 117 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); 118 119 static int netlink_dump(struct sock *sk); 120 static void netlink_destroy_callback(struct netlink_callback *cb); 121 122 static DEFINE_RWLOCK(nl_table_lock); 123 static atomic_t nl_table_users = ATOMIC_INIT(0); 124 125 static ATOMIC_NOTIFIER_HEAD(netlink_chain); 126 127 static u32 netlink_group_mask(u32 group) 128 { 129 return group ? 1 << (group - 1) : 0; 130 } 131 132 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid) 133 { 134 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask]; 135 } 136 137 static void netlink_sock_destruct(struct sock *sk) 138 { 139 skb_queue_purge(&sk->sk_receive_queue); 140 141 if (!sock_flag(sk, SOCK_DEAD)) { 142 printk("Freeing alive netlink socket %p\n", sk); 143 return; 144 } 145 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc)); 146 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc)); 147 BUG_TRAP(!nlk_sk(sk)->cb); 148 BUG_TRAP(!nlk_sk(sk)->groups); 149 } 150 151 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP. 152 * Look, when several writers sleep and reader wakes them up, all but one 153 * immediately hit write lock and grab all the cpus. Exclusive sleep solves 154 * this, _but_ remember, it adds useless work on UP machines. 155 */ 156 157 static void netlink_table_grab(void) 158 { 159 write_lock_irq(&nl_table_lock); 160 161 if (atomic_read(&nl_table_users)) { 162 DECLARE_WAITQUEUE(wait, current); 163 164 add_wait_queue_exclusive(&nl_table_wait, &wait); 165 for(;;) { 166 set_current_state(TASK_UNINTERRUPTIBLE); 167 if (atomic_read(&nl_table_users) == 0) 168 break; 169 write_unlock_irq(&nl_table_lock); 170 schedule(); 171 write_lock_irq(&nl_table_lock); 172 } 173 174 __set_current_state(TASK_RUNNING); 175 remove_wait_queue(&nl_table_wait, &wait); 176 } 177 } 178 179 static __inline__ void netlink_table_ungrab(void) 180 { 181 write_unlock_irq(&nl_table_lock); 182 wake_up(&nl_table_wait); 183 } 184 185 static __inline__ void 186 netlink_lock_table(void) 187 { 188 /* read_lock() synchronizes us to netlink_table_grab */ 189 190 read_lock(&nl_table_lock); 191 atomic_inc(&nl_table_users); 192 read_unlock(&nl_table_lock); 193 } 194 195 static __inline__ void 196 netlink_unlock_table(void) 197 { 198 if (atomic_dec_and_test(&nl_table_users)) 199 wake_up(&nl_table_wait); 200 } 201 202 static __inline__ struct sock *netlink_lookup(int protocol, u32 pid) 203 { 204 struct nl_pid_hash *hash = &nl_table[protocol].hash; 205 struct hlist_head *head; 206 struct sock *sk; 207 struct hlist_node *node; 208 209 read_lock(&nl_table_lock); 210 head = nl_pid_hashfn(hash, pid); 211 sk_for_each(sk, node, head) { 212 if (nlk_sk(sk)->pid == pid) { 213 sock_hold(sk); 214 goto found; 215 } 216 } 217 sk = NULL; 218 found: 219 read_unlock(&nl_table_lock); 220 return sk; 221 } 222 223 static inline struct hlist_head *nl_pid_hash_alloc(size_t size) 224 { 225 if (size <= PAGE_SIZE) 226 return kmalloc(size, GFP_ATOMIC); 227 else 228 return (struct hlist_head *) 229 __get_free_pages(GFP_ATOMIC, get_order(size)); 230 } 231 232 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size) 233 { 234 if (size <= PAGE_SIZE) 235 kfree(table); 236 else 237 free_pages((unsigned long)table, get_order(size)); 238 } 239 240 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow) 241 { 242 unsigned int omask, mask, shift; 243 size_t osize, size; 244 struct hlist_head *otable, *table; 245 int i; 246 247 omask = mask = hash->mask; 248 osize = size = (mask + 1) * sizeof(*table); 249 shift = hash->shift; 250 251 if (grow) { 252 if (++shift > hash->max_shift) 253 return 0; 254 mask = mask * 2 + 1; 255 size *= 2; 256 } 257 258 table = nl_pid_hash_alloc(size); 259 if (!table) 260 return 0; 261 262 memset(table, 0, size); 263 otable = hash->table; 264 hash->table = table; 265 hash->mask = mask; 266 hash->shift = shift; 267 get_random_bytes(&hash->rnd, sizeof(hash->rnd)); 268 269 for (i = 0; i <= omask; i++) { 270 struct sock *sk; 271 struct hlist_node *node, *tmp; 272 273 sk_for_each_safe(sk, node, tmp, &otable[i]) 274 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid)); 275 } 276 277 nl_pid_hash_free(otable, osize); 278 hash->rehash_time = jiffies + 10 * 60 * HZ; 279 return 1; 280 } 281 282 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len) 283 { 284 int avg = hash->entries >> hash->shift; 285 286 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1)) 287 return 1; 288 289 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) { 290 nl_pid_hash_rehash(hash, 0); 291 return 1; 292 } 293 294 return 0; 295 } 296 297 static const struct proto_ops netlink_ops; 298 299 static void 300 netlink_update_listeners(struct sock *sk) 301 { 302 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 303 struct hlist_node *node; 304 unsigned long mask; 305 unsigned int i; 306 307 for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) { 308 mask = 0; 309 sk_for_each_bound(sk, node, &tbl->mc_list) 310 mask |= nlk_sk(sk)->groups[i]; 311 tbl->listeners[i] = mask; 312 } 313 /* this function is only called with the netlink table "grabbed", which 314 * makes sure updates are visible before bind or setsockopt return. */ 315 } 316 317 static int netlink_insert(struct sock *sk, u32 pid) 318 { 319 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 320 struct hlist_head *head; 321 int err = -EADDRINUSE; 322 struct sock *osk; 323 struct hlist_node *node; 324 int len; 325 326 netlink_table_grab(); 327 head = nl_pid_hashfn(hash, pid); 328 len = 0; 329 sk_for_each(osk, node, head) { 330 if (nlk_sk(osk)->pid == pid) 331 break; 332 len++; 333 } 334 if (node) 335 goto err; 336 337 err = -EBUSY; 338 if (nlk_sk(sk)->pid) 339 goto err; 340 341 err = -ENOMEM; 342 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX)) 343 goto err; 344 345 if (len && nl_pid_hash_dilute(hash, len)) 346 head = nl_pid_hashfn(hash, pid); 347 hash->entries++; 348 nlk_sk(sk)->pid = pid; 349 sk_add_node(sk, head); 350 err = 0; 351 352 err: 353 netlink_table_ungrab(); 354 return err; 355 } 356 357 static void netlink_remove(struct sock *sk) 358 { 359 netlink_table_grab(); 360 if (sk_del_node_init(sk)) 361 nl_table[sk->sk_protocol].hash.entries--; 362 if (nlk_sk(sk)->subscriptions) 363 __sk_del_bind_node(sk); 364 netlink_table_ungrab(); 365 } 366 367 static struct proto netlink_proto = { 368 .name = "NETLINK", 369 .owner = THIS_MODULE, 370 .obj_size = sizeof(struct netlink_sock), 371 }; 372 373 static int __netlink_create(struct socket *sock, int protocol) 374 { 375 struct sock *sk; 376 struct netlink_sock *nlk; 377 378 sock->ops = &netlink_ops; 379 380 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1); 381 if (!sk) 382 return -ENOMEM; 383 384 sock_init_data(sock, sk); 385 386 nlk = nlk_sk(sk); 387 spin_lock_init(&nlk->cb_lock); 388 init_waitqueue_head(&nlk->wait); 389 390 sk->sk_destruct = netlink_sock_destruct; 391 sk->sk_protocol = protocol; 392 return 0; 393 } 394 395 static int netlink_create(struct socket *sock, int protocol) 396 { 397 struct module *module = NULL; 398 struct netlink_sock *nlk; 399 unsigned int groups; 400 int err = 0; 401 402 sock->state = SS_UNCONNECTED; 403 404 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) 405 return -ESOCKTNOSUPPORT; 406 407 if (protocol<0 || protocol >= MAX_LINKS) 408 return -EPROTONOSUPPORT; 409 410 netlink_lock_table(); 411 #ifdef CONFIG_KMOD 412 if (!nl_table[protocol].registered) { 413 netlink_unlock_table(); 414 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); 415 netlink_lock_table(); 416 } 417 #endif 418 if (nl_table[protocol].registered && 419 try_module_get(nl_table[protocol].module)) 420 module = nl_table[protocol].module; 421 groups = nl_table[protocol].groups; 422 netlink_unlock_table(); 423 424 if ((err = __netlink_create(sock, protocol)) < 0) 425 goto out_module; 426 427 nlk = nlk_sk(sock->sk); 428 nlk->module = module; 429 out: 430 return err; 431 432 out_module: 433 module_put(module); 434 goto out; 435 } 436 437 static int netlink_release(struct socket *sock) 438 { 439 struct sock *sk = sock->sk; 440 struct netlink_sock *nlk; 441 442 if (!sk) 443 return 0; 444 445 netlink_remove(sk); 446 nlk = nlk_sk(sk); 447 448 spin_lock(&nlk->cb_lock); 449 if (nlk->cb) { 450 if (nlk->cb->done) 451 nlk->cb->done(nlk->cb); 452 netlink_destroy_callback(nlk->cb); 453 nlk->cb = NULL; 454 } 455 spin_unlock(&nlk->cb_lock); 456 457 /* OK. Socket is unlinked, and, therefore, 458 no new packets will arrive */ 459 460 sock_orphan(sk); 461 sock->sk = NULL; 462 wake_up_interruptible_all(&nlk->wait); 463 464 skb_queue_purge(&sk->sk_write_queue); 465 466 if (nlk->pid && !nlk->subscriptions) { 467 struct netlink_notify n = { 468 .protocol = sk->sk_protocol, 469 .pid = nlk->pid, 470 }; 471 atomic_notifier_call_chain(&netlink_chain, 472 NETLINK_URELEASE, &n); 473 } 474 475 if (nlk->module) 476 module_put(nlk->module); 477 478 netlink_table_grab(); 479 if (nlk->flags & NETLINK_KERNEL_SOCKET) { 480 kfree(nl_table[sk->sk_protocol].listeners); 481 nl_table[sk->sk_protocol].module = NULL; 482 nl_table[sk->sk_protocol].registered = 0; 483 } else if (nlk->subscriptions) 484 netlink_update_listeners(sk); 485 netlink_table_ungrab(); 486 487 kfree(nlk->groups); 488 nlk->groups = NULL; 489 490 sock_put(sk); 491 return 0; 492 } 493 494 static int netlink_autobind(struct socket *sock) 495 { 496 struct sock *sk = sock->sk; 497 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 498 struct hlist_head *head; 499 struct sock *osk; 500 struct hlist_node *node; 501 s32 pid = current->tgid; 502 int err; 503 static s32 rover = -4097; 504 505 retry: 506 cond_resched(); 507 netlink_table_grab(); 508 head = nl_pid_hashfn(hash, pid); 509 sk_for_each(osk, node, head) { 510 if (nlk_sk(osk)->pid == pid) { 511 /* Bind collision, search negative pid values. */ 512 pid = rover--; 513 if (rover > -4097) 514 rover = -4097; 515 netlink_table_ungrab(); 516 goto retry; 517 } 518 } 519 netlink_table_ungrab(); 520 521 err = netlink_insert(sk, pid); 522 if (err == -EADDRINUSE) 523 goto retry; 524 525 /* If 2 threads race to autobind, that is fine. */ 526 if (err == -EBUSY) 527 err = 0; 528 529 return err; 530 } 531 532 static inline int netlink_capable(struct socket *sock, unsigned int flag) 533 { 534 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) || 535 capable(CAP_NET_ADMIN); 536 } 537 538 static void 539 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 540 { 541 struct netlink_sock *nlk = nlk_sk(sk); 542 543 if (nlk->subscriptions && !subscriptions) 544 __sk_del_bind_node(sk); 545 else if (!nlk->subscriptions && subscriptions) 546 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 547 nlk->subscriptions = subscriptions; 548 } 549 550 static int netlink_alloc_groups(struct sock *sk) 551 { 552 struct netlink_sock *nlk = nlk_sk(sk); 553 unsigned int groups; 554 int err = 0; 555 556 netlink_lock_table(); 557 groups = nl_table[sk->sk_protocol].groups; 558 if (!nl_table[sk->sk_protocol].registered) 559 err = -ENOENT; 560 netlink_unlock_table(); 561 562 if (err) 563 return err; 564 565 nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL); 566 if (nlk->groups == NULL) 567 return -ENOMEM; 568 nlk->ngroups = groups; 569 return 0; 570 } 571 572 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len) 573 { 574 struct sock *sk = sock->sk; 575 struct netlink_sock *nlk = nlk_sk(sk); 576 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 577 int err; 578 579 if (nladdr->nl_family != AF_NETLINK) 580 return -EINVAL; 581 582 /* Only superuser is allowed to listen multicasts */ 583 if (nladdr->nl_groups) { 584 if (!netlink_capable(sock, NL_NONROOT_RECV)) 585 return -EPERM; 586 if (nlk->groups == NULL) { 587 err = netlink_alloc_groups(sk); 588 if (err) 589 return err; 590 } 591 } 592 593 if (nlk->pid) { 594 if (nladdr->nl_pid != nlk->pid) 595 return -EINVAL; 596 } else { 597 err = nladdr->nl_pid ? 598 netlink_insert(sk, nladdr->nl_pid) : 599 netlink_autobind(sock); 600 if (err) 601 return err; 602 } 603 604 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) 605 return 0; 606 607 netlink_table_grab(); 608 netlink_update_subscriptions(sk, nlk->subscriptions + 609 hweight32(nladdr->nl_groups) - 610 hweight32(nlk->groups[0])); 611 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups; 612 netlink_update_listeners(sk); 613 netlink_table_ungrab(); 614 615 return 0; 616 } 617 618 static int netlink_connect(struct socket *sock, struct sockaddr *addr, 619 int alen, int flags) 620 { 621 int err = 0; 622 struct sock *sk = sock->sk; 623 struct netlink_sock *nlk = nlk_sk(sk); 624 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr; 625 626 if (addr->sa_family == AF_UNSPEC) { 627 sk->sk_state = NETLINK_UNCONNECTED; 628 nlk->dst_pid = 0; 629 nlk->dst_group = 0; 630 return 0; 631 } 632 if (addr->sa_family != AF_NETLINK) 633 return -EINVAL; 634 635 /* Only superuser is allowed to send multicasts */ 636 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND)) 637 return -EPERM; 638 639 if (!nlk->pid) 640 err = netlink_autobind(sock); 641 642 if (err == 0) { 643 sk->sk_state = NETLINK_CONNECTED; 644 nlk->dst_pid = nladdr->nl_pid; 645 nlk->dst_group = ffs(nladdr->nl_groups); 646 } 647 648 return err; 649 } 650 651 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer) 652 { 653 struct sock *sk = sock->sk; 654 struct netlink_sock *nlk = nlk_sk(sk); 655 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr; 656 657 nladdr->nl_family = AF_NETLINK; 658 nladdr->nl_pad = 0; 659 *addr_len = sizeof(*nladdr); 660 661 if (peer) { 662 nladdr->nl_pid = nlk->dst_pid; 663 nladdr->nl_groups = netlink_group_mask(nlk->dst_group); 664 } else { 665 nladdr->nl_pid = nlk->pid; 666 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 667 } 668 return 0; 669 } 670 671 static void netlink_overrun(struct sock *sk) 672 { 673 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) { 674 sk->sk_err = ENOBUFS; 675 sk->sk_error_report(sk); 676 } 677 } 678 679 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid) 680 { 681 int protocol = ssk->sk_protocol; 682 struct sock *sock; 683 struct netlink_sock *nlk; 684 685 sock = netlink_lookup(protocol, pid); 686 if (!sock) 687 return ERR_PTR(-ECONNREFUSED); 688 689 /* Don't bother queuing skb if kernel socket has no input function */ 690 nlk = nlk_sk(sock); 691 if ((nlk->pid == 0 && !nlk->data_ready) || 692 (sock->sk_state == NETLINK_CONNECTED && 693 nlk->dst_pid != nlk_sk(ssk)->pid)) { 694 sock_put(sock); 695 return ERR_PTR(-ECONNREFUSED); 696 } 697 return sock; 698 } 699 700 struct sock *netlink_getsockbyfilp(struct file *filp) 701 { 702 struct inode *inode = filp->f_dentry->d_inode; 703 struct sock *sock; 704 705 if (!S_ISSOCK(inode->i_mode)) 706 return ERR_PTR(-ENOTSOCK); 707 708 sock = SOCKET_I(inode)->sk; 709 if (sock->sk_family != AF_NETLINK) 710 return ERR_PTR(-EINVAL); 711 712 sock_hold(sock); 713 return sock; 714 } 715 716 /* 717 * Attach a skb to a netlink socket. 718 * The caller must hold a reference to the destination socket. On error, the 719 * reference is dropped. The skb is not send to the destination, just all 720 * all error checks are performed and memory in the queue is reserved. 721 * Return values: 722 * < 0: error. skb freed, reference to sock dropped. 723 * 0: continue 724 * 1: repeat lookup - reference dropped while waiting for socket memory. 725 */ 726 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, 727 long timeo, struct sock *ssk) 728 { 729 struct netlink_sock *nlk; 730 731 nlk = nlk_sk(sk); 732 733 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 734 test_bit(0, &nlk->state)) { 735 DECLARE_WAITQUEUE(wait, current); 736 if (!timeo) { 737 if (!ssk || nlk_sk(ssk)->pid == 0) 738 netlink_overrun(sk); 739 sock_put(sk); 740 kfree_skb(skb); 741 return -EAGAIN; 742 } 743 744 __set_current_state(TASK_INTERRUPTIBLE); 745 add_wait_queue(&nlk->wait, &wait); 746 747 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 748 test_bit(0, &nlk->state)) && 749 !sock_flag(sk, SOCK_DEAD)) 750 timeo = schedule_timeout(timeo); 751 752 __set_current_state(TASK_RUNNING); 753 remove_wait_queue(&nlk->wait, &wait); 754 sock_put(sk); 755 756 if (signal_pending(current)) { 757 kfree_skb(skb); 758 return sock_intr_errno(timeo); 759 } 760 return 1; 761 } 762 skb_set_owner_r(skb, sk); 763 return 0; 764 } 765 766 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol) 767 { 768 int len = skb->len; 769 770 skb_queue_tail(&sk->sk_receive_queue, skb); 771 sk->sk_data_ready(sk, len); 772 sock_put(sk); 773 return len; 774 } 775 776 void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 777 { 778 kfree_skb(skb); 779 sock_put(sk); 780 } 781 782 static inline struct sk_buff *netlink_trim(struct sk_buff *skb, 783 gfp_t allocation) 784 { 785 int delta; 786 787 skb_orphan(skb); 788 789 delta = skb->end - skb->tail; 790 if (delta * 2 < skb->truesize) 791 return skb; 792 793 if (skb_shared(skb)) { 794 struct sk_buff *nskb = skb_clone(skb, allocation); 795 if (!nskb) 796 return skb; 797 kfree_skb(skb); 798 skb = nskb; 799 } 800 801 if (!pskb_expand_head(skb, 0, -delta, allocation)) 802 skb->truesize -= delta; 803 804 return skb; 805 } 806 807 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock) 808 { 809 struct sock *sk; 810 int err; 811 long timeo; 812 813 skb = netlink_trim(skb, gfp_any()); 814 815 timeo = sock_sndtimeo(ssk, nonblock); 816 retry: 817 sk = netlink_getsockbypid(ssk, pid); 818 if (IS_ERR(sk)) { 819 kfree_skb(skb); 820 return PTR_ERR(sk); 821 } 822 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk); 823 if (err == 1) 824 goto retry; 825 if (err) 826 return err; 827 828 return netlink_sendskb(sk, skb, ssk->sk_protocol); 829 } 830 831 int netlink_has_listeners(struct sock *sk, unsigned int group) 832 { 833 int res = 0; 834 835 BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET)); 836 if (group - 1 < nl_table[sk->sk_protocol].groups) 837 res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners); 838 return res; 839 } 840 EXPORT_SYMBOL_GPL(netlink_has_listeners); 841 842 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 843 { 844 struct netlink_sock *nlk = nlk_sk(sk); 845 846 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 847 !test_bit(0, &nlk->state)) { 848 skb_set_owner_r(skb, sk); 849 skb_queue_tail(&sk->sk_receive_queue, skb); 850 sk->sk_data_ready(sk, skb->len); 851 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf; 852 } 853 return -1; 854 } 855 856 struct netlink_broadcast_data { 857 struct sock *exclude_sk; 858 u32 pid; 859 u32 group; 860 int failure; 861 int congested; 862 int delivered; 863 gfp_t allocation; 864 struct sk_buff *skb, *skb2; 865 }; 866 867 static inline int do_one_broadcast(struct sock *sk, 868 struct netlink_broadcast_data *p) 869 { 870 struct netlink_sock *nlk = nlk_sk(sk); 871 int val; 872 873 if (p->exclude_sk == sk) 874 goto out; 875 876 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 877 !test_bit(p->group - 1, nlk->groups)) 878 goto out; 879 880 if (p->failure) { 881 netlink_overrun(sk); 882 goto out; 883 } 884 885 sock_hold(sk); 886 if (p->skb2 == NULL) { 887 if (skb_shared(p->skb)) { 888 p->skb2 = skb_clone(p->skb, p->allocation); 889 } else { 890 p->skb2 = skb_get(p->skb); 891 /* 892 * skb ownership may have been set when 893 * delivered to a previous socket. 894 */ 895 skb_orphan(p->skb2); 896 } 897 } 898 if (p->skb2 == NULL) { 899 netlink_overrun(sk); 900 /* Clone failed. Notify ALL listeners. */ 901 p->failure = 1; 902 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) { 903 netlink_overrun(sk); 904 } else { 905 p->congested |= val; 906 p->delivered = 1; 907 p->skb2 = NULL; 908 } 909 sock_put(sk); 910 911 out: 912 return 0; 913 } 914 915 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid, 916 u32 group, gfp_t allocation) 917 { 918 struct netlink_broadcast_data info; 919 struct hlist_node *node; 920 struct sock *sk; 921 922 skb = netlink_trim(skb, allocation); 923 924 info.exclude_sk = ssk; 925 info.pid = pid; 926 info.group = group; 927 info.failure = 0; 928 info.congested = 0; 929 info.delivered = 0; 930 info.allocation = allocation; 931 info.skb = skb; 932 info.skb2 = NULL; 933 934 /* While we sleep in clone, do not allow to change socket list */ 935 936 netlink_lock_table(); 937 938 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 939 do_one_broadcast(sk, &info); 940 941 kfree_skb(skb); 942 943 netlink_unlock_table(); 944 945 if (info.skb2) 946 kfree_skb(info.skb2); 947 948 if (info.delivered) { 949 if (info.congested && (allocation & __GFP_WAIT)) 950 yield(); 951 return 0; 952 } 953 if (info.failure) 954 return -ENOBUFS; 955 return -ESRCH; 956 } 957 958 struct netlink_set_err_data { 959 struct sock *exclude_sk; 960 u32 pid; 961 u32 group; 962 int code; 963 }; 964 965 static inline int do_one_set_err(struct sock *sk, 966 struct netlink_set_err_data *p) 967 { 968 struct netlink_sock *nlk = nlk_sk(sk); 969 970 if (sk == p->exclude_sk) 971 goto out; 972 973 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 974 !test_bit(p->group - 1, nlk->groups)) 975 goto out; 976 977 sk->sk_err = p->code; 978 sk->sk_error_report(sk); 979 out: 980 return 0; 981 } 982 983 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code) 984 { 985 struct netlink_set_err_data info; 986 struct hlist_node *node; 987 struct sock *sk; 988 989 info.exclude_sk = ssk; 990 info.pid = pid; 991 info.group = group; 992 info.code = code; 993 994 read_lock(&nl_table_lock); 995 996 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 997 do_one_set_err(sk, &info); 998 999 read_unlock(&nl_table_lock); 1000 } 1001 1002 static int netlink_setsockopt(struct socket *sock, int level, int optname, 1003 char __user *optval, int optlen) 1004 { 1005 struct sock *sk = sock->sk; 1006 struct netlink_sock *nlk = nlk_sk(sk); 1007 int val = 0, err; 1008 1009 if (level != SOL_NETLINK) 1010 return -ENOPROTOOPT; 1011 1012 if (optlen >= sizeof(int) && 1013 get_user(val, (int __user *)optval)) 1014 return -EFAULT; 1015 1016 switch (optname) { 1017 case NETLINK_PKTINFO: 1018 if (val) 1019 nlk->flags |= NETLINK_RECV_PKTINFO; 1020 else 1021 nlk->flags &= ~NETLINK_RECV_PKTINFO; 1022 err = 0; 1023 break; 1024 case NETLINK_ADD_MEMBERSHIP: 1025 case NETLINK_DROP_MEMBERSHIP: { 1026 unsigned int subscriptions; 1027 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0; 1028 1029 if (!netlink_capable(sock, NL_NONROOT_RECV)) 1030 return -EPERM; 1031 if (nlk->groups == NULL) { 1032 err = netlink_alloc_groups(sk); 1033 if (err) 1034 return err; 1035 } 1036 if (!val || val - 1 >= nlk->ngroups) 1037 return -EINVAL; 1038 netlink_table_grab(); 1039 old = test_bit(val - 1, nlk->groups); 1040 subscriptions = nlk->subscriptions - old + new; 1041 if (new) 1042 __set_bit(val - 1, nlk->groups); 1043 else 1044 __clear_bit(val - 1, nlk->groups); 1045 netlink_update_subscriptions(sk, subscriptions); 1046 netlink_update_listeners(sk); 1047 netlink_table_ungrab(); 1048 err = 0; 1049 break; 1050 } 1051 default: 1052 err = -ENOPROTOOPT; 1053 } 1054 return err; 1055 } 1056 1057 static int netlink_getsockopt(struct socket *sock, int level, int optname, 1058 char __user *optval, int __user *optlen) 1059 { 1060 struct sock *sk = sock->sk; 1061 struct netlink_sock *nlk = nlk_sk(sk); 1062 int len, val, err; 1063 1064 if (level != SOL_NETLINK) 1065 return -ENOPROTOOPT; 1066 1067 if (get_user(len, optlen)) 1068 return -EFAULT; 1069 if (len < 0) 1070 return -EINVAL; 1071 1072 switch (optname) { 1073 case NETLINK_PKTINFO: 1074 if (len < sizeof(int)) 1075 return -EINVAL; 1076 len = sizeof(int); 1077 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0; 1078 put_user(len, optlen); 1079 put_user(val, optval); 1080 err = 0; 1081 break; 1082 default: 1083 err = -ENOPROTOOPT; 1084 } 1085 return err; 1086 } 1087 1088 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1089 { 1090 struct nl_pktinfo info; 1091 1092 info.group = NETLINK_CB(skb).dst_group; 1093 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1094 } 1095 1096 static inline void netlink_rcv_wake(struct sock *sk) 1097 { 1098 struct netlink_sock *nlk = nlk_sk(sk); 1099 1100 if (skb_queue_empty(&sk->sk_receive_queue)) 1101 clear_bit(0, &nlk->state); 1102 if (!test_bit(0, &nlk->state)) 1103 wake_up_interruptible(&nlk->wait); 1104 } 1105 1106 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock, 1107 struct msghdr *msg, size_t len) 1108 { 1109 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1110 struct sock *sk = sock->sk; 1111 struct netlink_sock *nlk = nlk_sk(sk); 1112 struct sockaddr_nl *addr=msg->msg_name; 1113 u32 dst_pid; 1114 u32 dst_group; 1115 struct sk_buff *skb; 1116 int err; 1117 struct scm_cookie scm; 1118 1119 if (msg->msg_flags&MSG_OOB) 1120 return -EOPNOTSUPP; 1121 1122 if (NULL == siocb->scm) 1123 siocb->scm = &scm; 1124 err = scm_send(sock, msg, siocb->scm); 1125 if (err < 0) 1126 return err; 1127 1128 if (msg->msg_namelen) { 1129 if (addr->nl_family != AF_NETLINK) 1130 return -EINVAL; 1131 dst_pid = addr->nl_pid; 1132 dst_group = ffs(addr->nl_groups); 1133 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND)) 1134 return -EPERM; 1135 } else { 1136 dst_pid = nlk->dst_pid; 1137 dst_group = nlk->dst_group; 1138 } 1139 1140 if (!nlk->pid) { 1141 err = netlink_autobind(sock); 1142 if (err) 1143 goto out; 1144 } 1145 1146 err = -EMSGSIZE; 1147 if (len > sk->sk_sndbuf - 32) 1148 goto out; 1149 err = -ENOBUFS; 1150 skb = alloc_skb(len, GFP_KERNEL); 1151 if (skb==NULL) 1152 goto out; 1153 1154 NETLINK_CB(skb).pid = nlk->pid; 1155 NETLINK_CB(skb).dst_pid = dst_pid; 1156 NETLINK_CB(skb).dst_group = dst_group; 1157 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context); 1158 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid)); 1159 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1160 1161 /* What can I do? Netlink is asynchronous, so that 1162 we will have to save current capabilities to 1163 check them, when this message will be delivered 1164 to corresponding kernel module. --ANK (980802) 1165 */ 1166 1167 err = -EFAULT; 1168 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) { 1169 kfree_skb(skb); 1170 goto out; 1171 } 1172 1173 err = security_netlink_send(sk, skb); 1174 if (err) { 1175 kfree_skb(skb); 1176 goto out; 1177 } 1178 1179 if (dst_group) { 1180 atomic_inc(&skb->users); 1181 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL); 1182 } 1183 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT); 1184 1185 out: 1186 return err; 1187 } 1188 1189 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, 1190 struct msghdr *msg, size_t len, 1191 int flags) 1192 { 1193 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1194 struct scm_cookie scm; 1195 struct sock *sk = sock->sk; 1196 struct netlink_sock *nlk = nlk_sk(sk); 1197 int noblock = flags&MSG_DONTWAIT; 1198 size_t copied; 1199 struct sk_buff *skb; 1200 int err; 1201 1202 if (flags&MSG_OOB) 1203 return -EOPNOTSUPP; 1204 1205 copied = 0; 1206 1207 skb = skb_recv_datagram(sk,flags,noblock,&err); 1208 if (skb==NULL) 1209 goto out; 1210 1211 msg->msg_namelen = 0; 1212 1213 copied = skb->len; 1214 if (len < copied) { 1215 msg->msg_flags |= MSG_TRUNC; 1216 copied = len; 1217 } 1218 1219 skb->h.raw = skb->data; 1220 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); 1221 1222 if (msg->msg_name) { 1223 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name; 1224 addr->nl_family = AF_NETLINK; 1225 addr->nl_pad = 0; 1226 addr->nl_pid = NETLINK_CB(skb).pid; 1227 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1228 msg->msg_namelen = sizeof(*addr); 1229 } 1230 1231 if (nlk->flags & NETLINK_RECV_PKTINFO) 1232 netlink_cmsg_recv_pktinfo(msg, skb); 1233 1234 if (NULL == siocb->scm) { 1235 memset(&scm, 0, sizeof(scm)); 1236 siocb->scm = &scm; 1237 } 1238 siocb->scm->creds = *NETLINK_CREDS(skb); 1239 skb_free_datagram(sk, skb); 1240 1241 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) 1242 netlink_dump(sk); 1243 1244 scm_recv(sock, msg, siocb->scm, flags); 1245 1246 out: 1247 netlink_rcv_wake(sk); 1248 return err ? : copied; 1249 } 1250 1251 static void netlink_data_ready(struct sock *sk, int len) 1252 { 1253 struct netlink_sock *nlk = nlk_sk(sk); 1254 1255 if (nlk->data_ready) 1256 nlk->data_ready(sk, len); 1257 netlink_rcv_wake(sk); 1258 } 1259 1260 /* 1261 * We export these functions to other modules. They provide a 1262 * complete set of kernel non-blocking support for message 1263 * queueing. 1264 */ 1265 1266 struct sock * 1267 netlink_kernel_create(int unit, unsigned int groups, 1268 void (*input)(struct sock *sk, int len), 1269 struct module *module) 1270 { 1271 struct socket *sock; 1272 struct sock *sk; 1273 struct netlink_sock *nlk; 1274 unsigned long *listeners = NULL; 1275 1276 if (!nl_table) 1277 return NULL; 1278 1279 if (unit<0 || unit>=MAX_LINKS) 1280 return NULL; 1281 1282 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 1283 return NULL; 1284 1285 if (__netlink_create(sock, unit) < 0) 1286 goto out_sock_release; 1287 1288 if (groups < 32) 1289 groups = 32; 1290 1291 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL); 1292 if (!listeners) 1293 goto out_sock_release; 1294 1295 sk = sock->sk; 1296 sk->sk_data_ready = netlink_data_ready; 1297 if (input) 1298 nlk_sk(sk)->data_ready = input; 1299 1300 if (netlink_insert(sk, 0)) 1301 goto out_sock_release; 1302 1303 nlk = nlk_sk(sk); 1304 nlk->flags |= NETLINK_KERNEL_SOCKET; 1305 1306 netlink_table_grab(); 1307 nl_table[unit].groups = groups; 1308 nl_table[unit].listeners = listeners; 1309 nl_table[unit].module = module; 1310 nl_table[unit].registered = 1; 1311 netlink_table_ungrab(); 1312 1313 return sk; 1314 1315 out_sock_release: 1316 kfree(listeners); 1317 sock_release(sock); 1318 return NULL; 1319 } 1320 1321 void netlink_set_nonroot(int protocol, unsigned int flags) 1322 { 1323 if ((unsigned int)protocol < MAX_LINKS) 1324 nl_table[protocol].nl_nonroot = flags; 1325 } 1326 1327 static void netlink_destroy_callback(struct netlink_callback *cb) 1328 { 1329 if (cb->skb) 1330 kfree_skb(cb->skb); 1331 kfree(cb); 1332 } 1333 1334 /* 1335 * It looks a bit ugly. 1336 * It would be better to create kernel thread. 1337 */ 1338 1339 static int netlink_dump(struct sock *sk) 1340 { 1341 struct netlink_sock *nlk = nlk_sk(sk); 1342 struct netlink_callback *cb; 1343 struct sk_buff *skb; 1344 struct nlmsghdr *nlh; 1345 int len; 1346 1347 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL); 1348 if (!skb) 1349 return -ENOBUFS; 1350 1351 spin_lock(&nlk->cb_lock); 1352 1353 cb = nlk->cb; 1354 if (cb == NULL) { 1355 spin_unlock(&nlk->cb_lock); 1356 kfree_skb(skb); 1357 return -EINVAL; 1358 } 1359 1360 len = cb->dump(skb, cb); 1361 1362 if (len > 0) { 1363 spin_unlock(&nlk->cb_lock); 1364 skb_queue_tail(&sk->sk_receive_queue, skb); 1365 sk->sk_data_ready(sk, len); 1366 return 0; 1367 } 1368 1369 nlh = NLMSG_NEW_ANSWER(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); 1370 memcpy(NLMSG_DATA(nlh), &len, sizeof(len)); 1371 skb_queue_tail(&sk->sk_receive_queue, skb); 1372 sk->sk_data_ready(sk, skb->len); 1373 1374 if (cb->done) 1375 cb->done(cb); 1376 nlk->cb = NULL; 1377 spin_unlock(&nlk->cb_lock); 1378 1379 netlink_destroy_callback(cb); 1380 return 0; 1381 1382 nlmsg_failure: 1383 return -ENOBUFS; 1384 } 1385 1386 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 1387 struct nlmsghdr *nlh, 1388 int (*dump)(struct sk_buff *skb, struct netlink_callback*), 1389 int (*done)(struct netlink_callback*)) 1390 { 1391 struct netlink_callback *cb; 1392 struct sock *sk; 1393 struct netlink_sock *nlk; 1394 1395 cb = kzalloc(sizeof(*cb), GFP_KERNEL); 1396 if (cb == NULL) 1397 return -ENOBUFS; 1398 1399 cb->dump = dump; 1400 cb->done = done; 1401 cb->nlh = nlh; 1402 atomic_inc(&skb->users); 1403 cb->skb = skb; 1404 1405 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid); 1406 if (sk == NULL) { 1407 netlink_destroy_callback(cb); 1408 return -ECONNREFUSED; 1409 } 1410 nlk = nlk_sk(sk); 1411 /* A dump is in progress... */ 1412 spin_lock(&nlk->cb_lock); 1413 if (nlk->cb) { 1414 spin_unlock(&nlk->cb_lock); 1415 netlink_destroy_callback(cb); 1416 sock_put(sk); 1417 return -EBUSY; 1418 } 1419 nlk->cb = cb; 1420 spin_unlock(&nlk->cb_lock); 1421 1422 netlink_dump(sk); 1423 sock_put(sk); 1424 return 0; 1425 } 1426 1427 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) 1428 { 1429 struct sk_buff *skb; 1430 struct nlmsghdr *rep; 1431 struct nlmsgerr *errmsg; 1432 int size; 1433 1434 if (err == 0) 1435 size = NLMSG_SPACE(sizeof(struct nlmsgerr)); 1436 else 1437 size = NLMSG_SPACE(4 + NLMSG_ALIGN(nlh->nlmsg_len)); 1438 1439 skb = alloc_skb(size, GFP_KERNEL); 1440 if (!skb) { 1441 struct sock *sk; 1442 1443 sk = netlink_lookup(in_skb->sk->sk_protocol, 1444 NETLINK_CB(in_skb).pid); 1445 if (sk) { 1446 sk->sk_err = ENOBUFS; 1447 sk->sk_error_report(sk); 1448 sock_put(sk); 1449 } 1450 return; 1451 } 1452 1453 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, 1454 NLMSG_ERROR, sizeof(struct nlmsgerr), 0); 1455 errmsg = NLMSG_DATA(rep); 1456 errmsg->error = err; 1457 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(struct nlmsghdr)); 1458 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT); 1459 } 1460 1461 static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 1462 struct nlmsghdr *, int *)) 1463 { 1464 unsigned int total_len; 1465 struct nlmsghdr *nlh; 1466 int err; 1467 1468 while (skb->len >= nlmsg_total_size(0)) { 1469 nlh = (struct nlmsghdr *) skb->data; 1470 1471 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 1472 return 0; 1473 1474 total_len = min(NLMSG_ALIGN(nlh->nlmsg_len), skb->len); 1475 1476 if (cb(skb, nlh, &err) < 0) { 1477 /* Not an error, but we have to interrupt processing 1478 * here. Note: that in this case we do not pull 1479 * message from skb, it will be processed later. 1480 */ 1481 if (err == 0) 1482 return -1; 1483 netlink_ack(skb, nlh, err); 1484 } else if (nlh->nlmsg_flags & NLM_F_ACK) 1485 netlink_ack(skb, nlh, 0); 1486 1487 skb_pull(skb, total_len); 1488 } 1489 1490 return 0; 1491 } 1492 1493 /** 1494 * nelink_run_queue - Process netlink receive queue. 1495 * @sk: Netlink socket containing the queue 1496 * @qlen: Place to store queue length upon entry 1497 * @cb: Callback function invoked for each netlink message found 1498 * 1499 * Processes as much as there was in the queue upon entry and invokes 1500 * a callback function for each netlink message found. The callback 1501 * function may refuse a message by returning a negative error code 1502 * but setting the error pointer to 0 in which case this function 1503 * returns with a qlen != 0. 1504 * 1505 * qlen must be initialized to 0 before the initial entry, afterwards 1506 * the function may be called repeatedly until qlen reaches 0. 1507 */ 1508 void netlink_run_queue(struct sock *sk, unsigned int *qlen, 1509 int (*cb)(struct sk_buff *, struct nlmsghdr *, int *)) 1510 { 1511 struct sk_buff *skb; 1512 1513 if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue)) 1514 *qlen = skb_queue_len(&sk->sk_receive_queue); 1515 1516 for (; *qlen; (*qlen)--) { 1517 skb = skb_dequeue(&sk->sk_receive_queue); 1518 if (netlink_rcv_skb(skb, cb)) { 1519 if (skb->len) 1520 skb_queue_head(&sk->sk_receive_queue, skb); 1521 else { 1522 kfree_skb(skb); 1523 (*qlen)--; 1524 } 1525 break; 1526 } 1527 1528 kfree_skb(skb); 1529 } 1530 } 1531 1532 /** 1533 * netlink_queue_skip - Skip netlink message while processing queue. 1534 * @nlh: Netlink message to be skipped 1535 * @skb: Socket buffer containing the netlink messages. 1536 * 1537 * Pulls the given netlink message off the socket buffer so the next 1538 * call to netlink_queue_run() will not reconsider the message. 1539 */ 1540 void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb) 1541 { 1542 int msglen = NLMSG_ALIGN(nlh->nlmsg_len); 1543 1544 if (msglen > skb->len) 1545 msglen = skb->len; 1546 1547 skb_pull(skb, msglen); 1548 } 1549 1550 #ifdef CONFIG_PROC_FS 1551 struct nl_seq_iter { 1552 int link; 1553 int hash_idx; 1554 }; 1555 1556 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos) 1557 { 1558 struct nl_seq_iter *iter = seq->private; 1559 int i, j; 1560 struct sock *s; 1561 struct hlist_node *node; 1562 loff_t off = 0; 1563 1564 for (i=0; i<MAX_LINKS; i++) { 1565 struct nl_pid_hash *hash = &nl_table[i].hash; 1566 1567 for (j = 0; j <= hash->mask; j++) { 1568 sk_for_each(s, node, &hash->table[j]) { 1569 if (off == pos) { 1570 iter->link = i; 1571 iter->hash_idx = j; 1572 return s; 1573 } 1574 ++off; 1575 } 1576 } 1577 } 1578 return NULL; 1579 } 1580 1581 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos) 1582 { 1583 read_lock(&nl_table_lock); 1584 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN; 1585 } 1586 1587 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1588 { 1589 struct sock *s; 1590 struct nl_seq_iter *iter; 1591 int i, j; 1592 1593 ++*pos; 1594 1595 if (v == SEQ_START_TOKEN) 1596 return netlink_seq_socket_idx(seq, 0); 1597 1598 s = sk_next(v); 1599 if (s) 1600 return s; 1601 1602 iter = seq->private; 1603 i = iter->link; 1604 j = iter->hash_idx + 1; 1605 1606 do { 1607 struct nl_pid_hash *hash = &nl_table[i].hash; 1608 1609 for (; j <= hash->mask; j++) { 1610 s = sk_head(&hash->table[j]); 1611 if (s) { 1612 iter->link = i; 1613 iter->hash_idx = j; 1614 return s; 1615 } 1616 } 1617 1618 j = 0; 1619 } while (++i < MAX_LINKS); 1620 1621 return NULL; 1622 } 1623 1624 static void netlink_seq_stop(struct seq_file *seq, void *v) 1625 { 1626 read_unlock(&nl_table_lock); 1627 } 1628 1629 1630 static int netlink_seq_show(struct seq_file *seq, void *v) 1631 { 1632 if (v == SEQ_START_TOKEN) 1633 seq_puts(seq, 1634 "sk Eth Pid Groups " 1635 "Rmem Wmem Dump Locks\n"); 1636 else { 1637 struct sock *s = v; 1638 struct netlink_sock *nlk = nlk_sk(s); 1639 1640 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n", 1641 s, 1642 s->sk_protocol, 1643 nlk->pid, 1644 nlk->groups ? (u32)nlk->groups[0] : 0, 1645 atomic_read(&s->sk_rmem_alloc), 1646 atomic_read(&s->sk_wmem_alloc), 1647 nlk->cb, 1648 atomic_read(&s->sk_refcnt) 1649 ); 1650 1651 } 1652 return 0; 1653 } 1654 1655 static struct seq_operations netlink_seq_ops = { 1656 .start = netlink_seq_start, 1657 .next = netlink_seq_next, 1658 .stop = netlink_seq_stop, 1659 .show = netlink_seq_show, 1660 }; 1661 1662 1663 static int netlink_seq_open(struct inode *inode, struct file *file) 1664 { 1665 struct seq_file *seq; 1666 struct nl_seq_iter *iter; 1667 int err; 1668 1669 iter = kzalloc(sizeof(*iter), GFP_KERNEL); 1670 if (!iter) 1671 return -ENOMEM; 1672 1673 err = seq_open(file, &netlink_seq_ops); 1674 if (err) { 1675 kfree(iter); 1676 return err; 1677 } 1678 1679 seq = file->private_data; 1680 seq->private = iter; 1681 return 0; 1682 } 1683 1684 static struct file_operations netlink_seq_fops = { 1685 .owner = THIS_MODULE, 1686 .open = netlink_seq_open, 1687 .read = seq_read, 1688 .llseek = seq_lseek, 1689 .release = seq_release_private, 1690 }; 1691 1692 #endif 1693 1694 int netlink_register_notifier(struct notifier_block *nb) 1695 { 1696 return atomic_notifier_chain_register(&netlink_chain, nb); 1697 } 1698 1699 int netlink_unregister_notifier(struct notifier_block *nb) 1700 { 1701 return atomic_notifier_chain_unregister(&netlink_chain, nb); 1702 } 1703 1704 static const struct proto_ops netlink_ops = { 1705 .family = PF_NETLINK, 1706 .owner = THIS_MODULE, 1707 .release = netlink_release, 1708 .bind = netlink_bind, 1709 .connect = netlink_connect, 1710 .socketpair = sock_no_socketpair, 1711 .accept = sock_no_accept, 1712 .getname = netlink_getname, 1713 .poll = datagram_poll, 1714 .ioctl = sock_no_ioctl, 1715 .listen = sock_no_listen, 1716 .shutdown = sock_no_shutdown, 1717 .setsockopt = netlink_setsockopt, 1718 .getsockopt = netlink_getsockopt, 1719 .sendmsg = netlink_sendmsg, 1720 .recvmsg = netlink_recvmsg, 1721 .mmap = sock_no_mmap, 1722 .sendpage = sock_no_sendpage, 1723 }; 1724 1725 static struct net_proto_family netlink_family_ops = { 1726 .family = PF_NETLINK, 1727 .create = netlink_create, 1728 .owner = THIS_MODULE, /* for consistency 8) */ 1729 }; 1730 1731 extern void netlink_skb_parms_too_large(void); 1732 1733 static int __init netlink_proto_init(void) 1734 { 1735 struct sk_buff *dummy_skb; 1736 int i; 1737 unsigned long max; 1738 unsigned int order; 1739 int err = proto_register(&netlink_proto, 0); 1740 1741 if (err != 0) 1742 goto out; 1743 1744 if (sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb)) 1745 netlink_skb_parms_too_large(); 1746 1747 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 1748 if (!nl_table) { 1749 enomem: 1750 printk(KERN_CRIT "netlink_init: Cannot allocate nl_table\n"); 1751 return -ENOMEM; 1752 } 1753 1754 if (num_physpages >= (128 * 1024)) 1755 max = num_physpages >> (21 - PAGE_SHIFT); 1756 else 1757 max = num_physpages >> (23 - PAGE_SHIFT); 1758 1759 order = get_bitmask_order(max) - 1 + PAGE_SHIFT; 1760 max = (1UL << order) / sizeof(struct hlist_head); 1761 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1; 1762 1763 for (i = 0; i < MAX_LINKS; i++) { 1764 struct nl_pid_hash *hash = &nl_table[i].hash; 1765 1766 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table)); 1767 if (!hash->table) { 1768 while (i-- > 0) 1769 nl_pid_hash_free(nl_table[i].hash.table, 1770 1 * sizeof(*hash->table)); 1771 kfree(nl_table); 1772 goto enomem; 1773 } 1774 memset(hash->table, 0, 1 * sizeof(*hash->table)); 1775 hash->max_shift = order; 1776 hash->shift = 0; 1777 hash->mask = 0; 1778 hash->rehash_time = jiffies; 1779 } 1780 1781 sock_register(&netlink_family_ops); 1782 #ifdef CONFIG_PROC_FS 1783 proc_net_fops_create("netlink", 0, &netlink_seq_fops); 1784 #endif 1785 /* The netlink device handler may be needed early. */ 1786 rtnetlink_init(); 1787 out: 1788 return err; 1789 } 1790 1791 core_initcall(netlink_proto_init); 1792 1793 EXPORT_SYMBOL(netlink_ack); 1794 EXPORT_SYMBOL(netlink_run_queue); 1795 EXPORT_SYMBOL(netlink_queue_skip); 1796 EXPORT_SYMBOL(netlink_broadcast); 1797 EXPORT_SYMBOL(netlink_dump_start); 1798 EXPORT_SYMBOL(netlink_kernel_create); 1799 EXPORT_SYMBOL(netlink_register_notifier); 1800 EXPORT_SYMBOL(netlink_set_err); 1801 EXPORT_SYMBOL(netlink_set_nonroot); 1802 EXPORT_SYMBOL(netlink_unicast); 1803 EXPORT_SYMBOL(netlink_unregister_notifier); 1804 1805