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/config.h> 25 #include <linux/module.h> 26 27 #include <linux/capability.h> 28 #include <linux/kernel.h> 29 #include <linux/init.h> 30 #include <linux/signal.h> 31 #include <linux/sched.h> 32 #include <linux/errno.h> 33 #include <linux/string.h> 34 #include <linux/stat.h> 35 #include <linux/socket.h> 36 #include <linux/un.h> 37 #include <linux/fcntl.h> 38 #include <linux/termios.h> 39 #include <linux/sockios.h> 40 #include <linux/net.h> 41 #include <linux/fs.h> 42 #include <linux/slab.h> 43 #include <asm/uaccess.h> 44 #include <linux/skbuff.h> 45 #include <linux/netdevice.h> 46 #include <linux/rtnetlink.h> 47 #include <linux/proc_fs.h> 48 #include <linux/seq_file.h> 49 #include <linux/smp_lock.h> 50 #include <linux/notifier.h> 51 #include <linux/security.h> 52 #include <linux/jhash.h> 53 #include <linux/jiffies.h> 54 #include <linux/random.h> 55 #include <linux/bitops.h> 56 #include <linux/mm.h> 57 #include <linux/types.h> 58 #include <linux/audit.h> 59 #include <linux/selinux.h> 60 61 #include <net/sock.h> 62 #include <net/scm.h> 63 #include <net/netlink.h> 64 65 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) 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 spinlock_t cb_lock; 81 void (*data_ready)(struct sock *sk, int bytes); 82 struct module *module; 83 }; 84 85 #define NETLINK_KERNEL_SOCKET 0x1 86 #define NETLINK_RECV_PKTINFO 0x2 87 88 static inline struct netlink_sock *nlk_sk(struct sock *sk) 89 { 90 return (struct netlink_sock *)sk; 91 } 92 93 struct nl_pid_hash { 94 struct hlist_head *table; 95 unsigned long rehash_time; 96 97 unsigned int mask; 98 unsigned int shift; 99 100 unsigned int entries; 101 unsigned int max_shift; 102 103 u32 rnd; 104 }; 105 106 struct netlink_table { 107 struct nl_pid_hash hash; 108 struct hlist_head mc_list; 109 unsigned long *listeners; 110 unsigned int nl_nonroot; 111 unsigned int groups; 112 struct module *module; 113 int registered; 114 }; 115 116 static struct netlink_table *nl_table; 117 118 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); 119 120 static int netlink_dump(struct sock *sk); 121 static void netlink_destroy_callback(struct netlink_callback *cb); 122 123 static DEFINE_RWLOCK(nl_table_lock); 124 static atomic_t nl_table_users = ATOMIC_INIT(0); 125 126 static ATOMIC_NOTIFIER_HEAD(netlink_chain); 127 128 static u32 netlink_group_mask(u32 group) 129 { 130 return group ? 1 << (group - 1) : 0; 131 } 132 133 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid) 134 { 135 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask]; 136 } 137 138 static void netlink_sock_destruct(struct sock *sk) 139 { 140 skb_queue_purge(&sk->sk_receive_queue); 141 142 if (!sock_flag(sk, SOCK_DEAD)) { 143 printk("Freeing alive netlink socket %p\n", sk); 144 return; 145 } 146 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc)); 147 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc)); 148 BUG_TRAP(!nlk_sk(sk)->cb); 149 BUG_TRAP(!nlk_sk(sk)->groups); 150 } 151 152 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP. 153 * Look, when several writers sleep and reader wakes them up, all but one 154 * immediately hit write lock and grab all the cpus. Exclusive sleep solves 155 * this, _but_ remember, it adds useless work on UP machines. 156 */ 157 158 static void netlink_table_grab(void) 159 { 160 write_lock_bh(&nl_table_lock); 161 162 if (atomic_read(&nl_table_users)) { 163 DECLARE_WAITQUEUE(wait, current); 164 165 add_wait_queue_exclusive(&nl_table_wait, &wait); 166 for(;;) { 167 set_current_state(TASK_UNINTERRUPTIBLE); 168 if (atomic_read(&nl_table_users) == 0) 169 break; 170 write_unlock_bh(&nl_table_lock); 171 schedule(); 172 write_lock_bh(&nl_table_lock); 173 } 174 175 __set_current_state(TASK_RUNNING); 176 remove_wait_queue(&nl_table_wait, &wait); 177 } 178 } 179 180 static __inline__ void netlink_table_ungrab(void) 181 { 182 write_unlock_bh(&nl_table_lock); 183 wake_up(&nl_table_wait); 184 } 185 186 static __inline__ void 187 netlink_lock_table(void) 188 { 189 /* read_lock() synchronizes us to netlink_table_grab */ 190 191 read_lock(&nl_table_lock); 192 atomic_inc(&nl_table_users); 193 read_unlock(&nl_table_lock); 194 } 195 196 static __inline__ void 197 netlink_unlock_table(void) 198 { 199 if (atomic_dec_and_test(&nl_table_users)) 200 wake_up(&nl_table_wait); 201 } 202 203 static __inline__ struct sock *netlink_lookup(int protocol, u32 pid) 204 { 205 struct nl_pid_hash *hash = &nl_table[protocol].hash; 206 struct hlist_head *head; 207 struct sock *sk; 208 struct hlist_node *node; 209 210 read_lock(&nl_table_lock); 211 head = nl_pid_hashfn(hash, pid); 212 sk_for_each(sk, node, head) { 213 if (nlk_sk(sk)->pid == pid) { 214 sock_hold(sk); 215 goto found; 216 } 217 } 218 sk = NULL; 219 found: 220 read_unlock(&nl_table_lock); 221 return sk; 222 } 223 224 static inline struct hlist_head *nl_pid_hash_alloc(size_t size) 225 { 226 if (size <= PAGE_SIZE) 227 return kmalloc(size, GFP_ATOMIC); 228 else 229 return (struct hlist_head *) 230 __get_free_pages(GFP_ATOMIC, get_order(size)); 231 } 232 233 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size) 234 { 235 if (size <= PAGE_SIZE) 236 kfree(table); 237 else 238 free_pages((unsigned long)table, get_order(size)); 239 } 240 241 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow) 242 { 243 unsigned int omask, mask, shift; 244 size_t osize, size; 245 struct hlist_head *otable, *table; 246 int i; 247 248 omask = mask = hash->mask; 249 osize = size = (mask + 1) * sizeof(*table); 250 shift = hash->shift; 251 252 if (grow) { 253 if (++shift > hash->max_shift) 254 return 0; 255 mask = mask * 2 + 1; 256 size *= 2; 257 } 258 259 table = nl_pid_hash_alloc(size); 260 if (!table) 261 return 0; 262 263 memset(table, 0, size); 264 otable = hash->table; 265 hash->table = table; 266 hash->mask = mask; 267 hash->shift = shift; 268 get_random_bytes(&hash->rnd, sizeof(hash->rnd)); 269 270 for (i = 0; i <= omask; i++) { 271 struct sock *sk; 272 struct hlist_node *node, *tmp; 273 274 sk_for_each_safe(sk, node, tmp, &otable[i]) 275 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid)); 276 } 277 278 nl_pid_hash_free(otable, osize); 279 hash->rehash_time = jiffies + 10 * 60 * HZ; 280 return 1; 281 } 282 283 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len) 284 { 285 int avg = hash->entries >> hash->shift; 286 287 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1)) 288 return 1; 289 290 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) { 291 nl_pid_hash_rehash(hash, 0); 292 return 1; 293 } 294 295 return 0; 296 } 297 298 static const struct proto_ops netlink_ops; 299 300 static void 301 netlink_update_listeners(struct sock *sk) 302 { 303 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 304 struct hlist_node *node; 305 unsigned long mask; 306 unsigned int i; 307 308 for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) { 309 mask = 0; 310 sk_for_each_bound(sk, node, &tbl->mc_list) 311 mask |= nlk_sk(sk)->groups[i]; 312 tbl->listeners[i] = mask; 313 } 314 /* this function is only called with the netlink table "grabbed", which 315 * makes sure updates are visible before bind or setsockopt return. */ 316 } 317 318 static int netlink_insert(struct sock *sk, u32 pid) 319 { 320 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 321 struct hlist_head *head; 322 int err = -EADDRINUSE; 323 struct sock *osk; 324 struct hlist_node *node; 325 int len; 326 327 netlink_table_grab(); 328 head = nl_pid_hashfn(hash, pid); 329 len = 0; 330 sk_for_each(osk, node, head) { 331 if (nlk_sk(osk)->pid == pid) 332 break; 333 len++; 334 } 335 if (node) 336 goto err; 337 338 err = -EBUSY; 339 if (nlk_sk(sk)->pid) 340 goto err; 341 342 err = -ENOMEM; 343 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX)) 344 goto err; 345 346 if (len && nl_pid_hash_dilute(hash, len)) 347 head = nl_pid_hashfn(hash, pid); 348 hash->entries++; 349 nlk_sk(sk)->pid = pid; 350 sk_add_node(sk, head); 351 err = 0; 352 353 err: 354 netlink_table_ungrab(); 355 return err; 356 } 357 358 static void netlink_remove(struct sock *sk) 359 { 360 netlink_table_grab(); 361 if (sk_del_node_init(sk)) 362 nl_table[sk->sk_protocol].hash.entries--; 363 if (nlk_sk(sk)->subscriptions) 364 __sk_del_bind_node(sk); 365 netlink_table_ungrab(); 366 } 367 368 static struct proto netlink_proto = { 369 .name = "NETLINK", 370 .owner = THIS_MODULE, 371 .obj_size = sizeof(struct netlink_sock), 372 }; 373 374 static int __netlink_create(struct socket *sock, int protocol) 375 { 376 struct sock *sk; 377 struct netlink_sock *nlk; 378 379 sock->ops = &netlink_ops; 380 381 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1); 382 if (!sk) 383 return -ENOMEM; 384 385 sock_init_data(sock, sk); 386 387 nlk = nlk_sk(sk); 388 spin_lock_init(&nlk->cb_lock); 389 init_waitqueue_head(&nlk->wait); 390 391 sk->sk_destruct = netlink_sock_destruct; 392 sk->sk_protocol = protocol; 393 return 0; 394 } 395 396 static int netlink_create(struct socket *sock, int protocol) 397 { 398 struct module *module = NULL; 399 struct netlink_sock *nlk; 400 unsigned int groups; 401 int err = 0; 402 403 sock->state = SS_UNCONNECTED; 404 405 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) 406 return -ESOCKTNOSUPPORT; 407 408 if (protocol<0 || protocol >= MAX_LINKS) 409 return -EPROTONOSUPPORT; 410 411 netlink_lock_table(); 412 #ifdef CONFIG_KMOD 413 if (!nl_table[protocol].registered) { 414 netlink_unlock_table(); 415 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); 416 netlink_lock_table(); 417 } 418 #endif 419 if (nl_table[protocol].registered && 420 try_module_get(nl_table[protocol].module)) 421 module = nl_table[protocol].module; 422 groups = nl_table[protocol].groups; 423 netlink_unlock_table(); 424 425 if ((err = __netlink_create(sock, protocol)) < 0) 426 goto out_module; 427 428 nlk = nlk_sk(sock->sk); 429 nlk->module = module; 430 out: 431 return err; 432 433 out_module: 434 module_put(module); 435 goto out; 436 } 437 438 static int netlink_release(struct socket *sock) 439 { 440 struct sock *sk = sock->sk; 441 struct netlink_sock *nlk; 442 443 if (!sk) 444 return 0; 445 446 netlink_remove(sk); 447 nlk = nlk_sk(sk); 448 449 spin_lock(&nlk->cb_lock); 450 if (nlk->cb) { 451 if (nlk->cb->done) 452 nlk->cb->done(nlk->cb); 453 netlink_destroy_callback(nlk->cb); 454 nlk->cb = NULL; 455 } 456 spin_unlock(&nlk->cb_lock); 457 458 /* OK. Socket is unlinked, and, therefore, 459 no new packets will arrive */ 460 461 sock_orphan(sk); 462 sock->sk = NULL; 463 wake_up_interruptible_all(&nlk->wait); 464 465 skb_queue_purge(&sk->sk_write_queue); 466 467 if (nlk->pid && !nlk->subscriptions) { 468 struct netlink_notify n = { 469 .protocol = sk->sk_protocol, 470 .pid = nlk->pid, 471 }; 472 atomic_notifier_call_chain(&netlink_chain, 473 NETLINK_URELEASE, &n); 474 } 475 476 if (nlk->module) 477 module_put(nlk->module); 478 479 netlink_table_grab(); 480 if (nlk->flags & NETLINK_KERNEL_SOCKET) { 481 kfree(nl_table[sk->sk_protocol].listeners); 482 nl_table[sk->sk_protocol].module = NULL; 483 nl_table[sk->sk_protocol].registered = 0; 484 } else if (nlk->subscriptions) 485 netlink_update_listeners(sk); 486 netlink_table_ungrab(); 487 488 kfree(nlk->groups); 489 nlk->groups = NULL; 490 491 sock_put(sk); 492 return 0; 493 } 494 495 static int netlink_autobind(struct socket *sock) 496 { 497 struct sock *sk = sock->sk; 498 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 499 struct hlist_head *head; 500 struct sock *osk; 501 struct hlist_node *node; 502 s32 pid = current->tgid; 503 int err; 504 static s32 rover = -4097; 505 506 retry: 507 cond_resched(); 508 netlink_table_grab(); 509 head = nl_pid_hashfn(hash, pid); 510 sk_for_each(osk, node, head) { 511 if (nlk_sk(osk)->pid == pid) { 512 /* Bind collision, search negative pid values. */ 513 pid = rover--; 514 if (rover > -4097) 515 rover = -4097; 516 netlink_table_ungrab(); 517 goto retry; 518 } 519 } 520 netlink_table_ungrab(); 521 522 err = netlink_insert(sk, pid); 523 if (err == -EADDRINUSE) 524 goto retry; 525 526 /* If 2 threads race to autobind, that is fine. */ 527 if (err == -EBUSY) 528 err = 0; 529 530 return err; 531 } 532 533 static inline int netlink_capable(struct socket *sock, unsigned int flag) 534 { 535 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) || 536 capable(CAP_NET_ADMIN); 537 } 538 539 static void 540 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 541 { 542 struct netlink_sock *nlk = nlk_sk(sk); 543 544 if (nlk->subscriptions && !subscriptions) 545 __sk_del_bind_node(sk); 546 else if (!nlk->subscriptions && subscriptions) 547 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 548 nlk->subscriptions = subscriptions; 549 } 550 551 static int netlink_alloc_groups(struct sock *sk) 552 { 553 struct netlink_sock *nlk = nlk_sk(sk); 554 unsigned int groups; 555 int err = 0; 556 557 netlink_lock_table(); 558 groups = nl_table[sk->sk_protocol].groups; 559 if (!nl_table[sk->sk_protocol].registered) 560 err = -ENOENT; 561 netlink_unlock_table(); 562 563 if (err) 564 return err; 565 566 nlk->groups = kmalloc(NLGRPSZ(groups), GFP_KERNEL); 567 if (nlk->groups == NULL) 568 return -ENOMEM; 569 memset(nlk->groups, 0, NLGRPSZ(groups)); 570 nlk->ngroups = groups; 571 return 0; 572 } 573 574 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len) 575 { 576 struct sock *sk = sock->sk; 577 struct netlink_sock *nlk = nlk_sk(sk); 578 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 579 int err; 580 581 if (nladdr->nl_family != AF_NETLINK) 582 return -EINVAL; 583 584 /* Only superuser is allowed to listen multicasts */ 585 if (nladdr->nl_groups) { 586 if (!netlink_capable(sock, NL_NONROOT_RECV)) 587 return -EPERM; 588 if (nlk->groups == NULL) { 589 err = netlink_alloc_groups(sk); 590 if (err) 591 return err; 592 } 593 } 594 595 if (nlk->pid) { 596 if (nladdr->nl_pid != nlk->pid) 597 return -EINVAL; 598 } else { 599 err = nladdr->nl_pid ? 600 netlink_insert(sk, nladdr->nl_pid) : 601 netlink_autobind(sock); 602 if (err) 603 return err; 604 } 605 606 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) 607 return 0; 608 609 netlink_table_grab(); 610 netlink_update_subscriptions(sk, nlk->subscriptions + 611 hweight32(nladdr->nl_groups) - 612 hweight32(nlk->groups[0])); 613 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups; 614 netlink_update_listeners(sk); 615 netlink_table_ungrab(); 616 617 return 0; 618 } 619 620 static int netlink_connect(struct socket *sock, struct sockaddr *addr, 621 int alen, int flags) 622 { 623 int err = 0; 624 struct sock *sk = sock->sk; 625 struct netlink_sock *nlk = nlk_sk(sk); 626 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr; 627 628 if (addr->sa_family == AF_UNSPEC) { 629 sk->sk_state = NETLINK_UNCONNECTED; 630 nlk->dst_pid = 0; 631 nlk->dst_group = 0; 632 return 0; 633 } 634 if (addr->sa_family != AF_NETLINK) 635 return -EINVAL; 636 637 /* Only superuser is allowed to send multicasts */ 638 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND)) 639 return -EPERM; 640 641 if (!nlk->pid) 642 err = netlink_autobind(sock); 643 644 if (err == 0) { 645 sk->sk_state = NETLINK_CONNECTED; 646 nlk->dst_pid = nladdr->nl_pid; 647 nlk->dst_group = ffs(nladdr->nl_groups); 648 } 649 650 return err; 651 } 652 653 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer) 654 { 655 struct sock *sk = sock->sk; 656 struct netlink_sock *nlk = nlk_sk(sk); 657 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr; 658 659 nladdr->nl_family = AF_NETLINK; 660 nladdr->nl_pad = 0; 661 *addr_len = sizeof(*nladdr); 662 663 if (peer) { 664 nladdr->nl_pid = nlk->dst_pid; 665 nladdr->nl_groups = netlink_group_mask(nlk->dst_group); 666 } else { 667 nladdr->nl_pid = nlk->pid; 668 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 669 } 670 return 0; 671 } 672 673 static void netlink_overrun(struct sock *sk) 674 { 675 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) { 676 sk->sk_err = ENOBUFS; 677 sk->sk_error_report(sk); 678 } 679 } 680 681 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid) 682 { 683 int protocol = ssk->sk_protocol; 684 struct sock *sock; 685 struct netlink_sock *nlk; 686 687 sock = netlink_lookup(protocol, pid); 688 if (!sock) 689 return ERR_PTR(-ECONNREFUSED); 690 691 /* Don't bother queuing skb if kernel socket has no input function */ 692 nlk = nlk_sk(sock); 693 if ((nlk->pid == 0 && !nlk->data_ready) || 694 (sock->sk_state == NETLINK_CONNECTED && 695 nlk->dst_pid != nlk_sk(ssk)->pid)) { 696 sock_put(sock); 697 return ERR_PTR(-ECONNREFUSED); 698 } 699 return sock; 700 } 701 702 struct sock *netlink_getsockbyfilp(struct file *filp) 703 { 704 struct inode *inode = filp->f_dentry->d_inode; 705 struct sock *sock; 706 707 if (!S_ISSOCK(inode->i_mode)) 708 return ERR_PTR(-ENOTSOCK); 709 710 sock = SOCKET_I(inode)->sk; 711 if (sock->sk_family != AF_NETLINK) 712 return ERR_PTR(-EINVAL); 713 714 sock_hold(sock); 715 return sock; 716 } 717 718 /* 719 * Attach a skb to a netlink socket. 720 * The caller must hold a reference to the destination socket. On error, the 721 * reference is dropped. The skb is not send to the destination, just all 722 * all error checks are performed and memory in the queue is reserved. 723 * Return values: 724 * < 0: error. skb freed, reference to sock dropped. 725 * 0: continue 726 * 1: repeat lookup - reference dropped while waiting for socket memory. 727 */ 728 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, 729 long timeo, struct sock *ssk) 730 { 731 struct netlink_sock *nlk; 732 733 nlk = nlk_sk(sk); 734 735 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 736 test_bit(0, &nlk->state)) { 737 DECLARE_WAITQUEUE(wait, current); 738 if (!timeo) { 739 if (!ssk || nlk_sk(ssk)->pid == 0) 740 netlink_overrun(sk); 741 sock_put(sk); 742 kfree_skb(skb); 743 return -EAGAIN; 744 } 745 746 __set_current_state(TASK_INTERRUPTIBLE); 747 add_wait_queue(&nlk->wait, &wait); 748 749 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 750 test_bit(0, &nlk->state)) && 751 !sock_flag(sk, SOCK_DEAD)) 752 timeo = schedule_timeout(timeo); 753 754 __set_current_state(TASK_RUNNING); 755 remove_wait_queue(&nlk->wait, &wait); 756 sock_put(sk); 757 758 if (signal_pending(current)) { 759 kfree_skb(skb); 760 return sock_intr_errno(timeo); 761 } 762 return 1; 763 } 764 skb_set_owner_r(skb, sk); 765 return 0; 766 } 767 768 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol) 769 { 770 int len = skb->len; 771 772 skb_queue_tail(&sk->sk_receive_queue, skb); 773 sk->sk_data_ready(sk, len); 774 sock_put(sk); 775 return len; 776 } 777 778 void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 779 { 780 kfree_skb(skb); 781 sock_put(sk); 782 } 783 784 static inline struct sk_buff *netlink_trim(struct sk_buff *skb, 785 gfp_t allocation) 786 { 787 int delta; 788 789 skb_orphan(skb); 790 791 delta = skb->end - skb->tail; 792 if (delta * 2 < skb->truesize) 793 return skb; 794 795 if (skb_shared(skb)) { 796 struct sk_buff *nskb = skb_clone(skb, allocation); 797 if (!nskb) 798 return skb; 799 kfree_skb(skb); 800 skb = nskb; 801 } 802 803 if (!pskb_expand_head(skb, 0, -delta, allocation)) 804 skb->truesize -= delta; 805 806 return skb; 807 } 808 809 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock) 810 { 811 struct sock *sk; 812 int err; 813 long timeo; 814 815 skb = netlink_trim(skb, gfp_any()); 816 817 timeo = sock_sndtimeo(ssk, nonblock); 818 retry: 819 sk = netlink_getsockbypid(ssk, pid); 820 if (IS_ERR(sk)) { 821 kfree_skb(skb); 822 return PTR_ERR(sk); 823 } 824 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk); 825 if (err == 1) 826 goto retry; 827 if (err) 828 return err; 829 830 return netlink_sendskb(sk, skb, ssk->sk_protocol); 831 } 832 833 int netlink_has_listeners(struct sock *sk, unsigned int group) 834 { 835 int res = 0; 836 837 BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET)); 838 if (group - 1 < nl_table[sk->sk_protocol].groups) 839 res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners); 840 return res; 841 } 842 EXPORT_SYMBOL_GPL(netlink_has_listeners); 843 844 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 845 { 846 struct netlink_sock *nlk = nlk_sk(sk); 847 848 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 849 !test_bit(0, &nlk->state)) { 850 skb_set_owner_r(skb, sk); 851 skb_queue_tail(&sk->sk_receive_queue, skb); 852 sk->sk_data_ready(sk, skb->len); 853 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf; 854 } 855 return -1; 856 } 857 858 struct netlink_broadcast_data { 859 struct sock *exclude_sk; 860 u32 pid; 861 u32 group; 862 int failure; 863 int congested; 864 int delivered; 865 gfp_t allocation; 866 struct sk_buff *skb, *skb2; 867 }; 868 869 static inline int do_one_broadcast(struct sock *sk, 870 struct netlink_broadcast_data *p) 871 { 872 struct netlink_sock *nlk = nlk_sk(sk); 873 int val; 874 875 if (p->exclude_sk == sk) 876 goto out; 877 878 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 879 !test_bit(p->group - 1, nlk->groups)) 880 goto out; 881 882 if (p->failure) { 883 netlink_overrun(sk); 884 goto out; 885 } 886 887 sock_hold(sk); 888 if (p->skb2 == NULL) { 889 if (skb_shared(p->skb)) { 890 p->skb2 = skb_clone(p->skb, p->allocation); 891 } else { 892 p->skb2 = skb_get(p->skb); 893 /* 894 * skb ownership may have been set when 895 * delivered to a previous socket. 896 */ 897 skb_orphan(p->skb2); 898 } 899 } 900 if (p->skb2 == NULL) { 901 netlink_overrun(sk); 902 /* Clone failed. Notify ALL listeners. */ 903 p->failure = 1; 904 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) { 905 netlink_overrun(sk); 906 } else { 907 p->congested |= val; 908 p->delivered = 1; 909 p->skb2 = NULL; 910 } 911 sock_put(sk); 912 913 out: 914 return 0; 915 } 916 917 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid, 918 u32 group, gfp_t allocation) 919 { 920 struct netlink_broadcast_data info; 921 struct hlist_node *node; 922 struct sock *sk; 923 924 skb = netlink_trim(skb, allocation); 925 926 info.exclude_sk = ssk; 927 info.pid = pid; 928 info.group = group; 929 info.failure = 0; 930 info.congested = 0; 931 info.delivered = 0; 932 info.allocation = allocation; 933 info.skb = skb; 934 info.skb2 = NULL; 935 936 /* While we sleep in clone, do not allow to change socket list */ 937 938 netlink_lock_table(); 939 940 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 941 do_one_broadcast(sk, &info); 942 943 kfree_skb(skb); 944 945 netlink_unlock_table(); 946 947 if (info.skb2) 948 kfree_skb(info.skb2); 949 950 if (info.delivered) { 951 if (info.congested && (allocation & __GFP_WAIT)) 952 yield(); 953 return 0; 954 } 955 if (info.failure) 956 return -ENOBUFS; 957 return -ESRCH; 958 } 959 960 struct netlink_set_err_data { 961 struct sock *exclude_sk; 962 u32 pid; 963 u32 group; 964 int code; 965 }; 966 967 static inline int do_one_set_err(struct sock *sk, 968 struct netlink_set_err_data *p) 969 { 970 struct netlink_sock *nlk = nlk_sk(sk); 971 972 if (sk == p->exclude_sk) 973 goto out; 974 975 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 976 !test_bit(p->group - 1, nlk->groups)) 977 goto out; 978 979 sk->sk_err = p->code; 980 sk->sk_error_report(sk); 981 out: 982 return 0; 983 } 984 985 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code) 986 { 987 struct netlink_set_err_data info; 988 struct hlist_node *node; 989 struct sock *sk; 990 991 info.exclude_sk = ssk; 992 info.pid = pid; 993 info.group = group; 994 info.code = code; 995 996 read_lock(&nl_table_lock); 997 998 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 999 do_one_set_err(sk, &info); 1000 1001 read_unlock(&nl_table_lock); 1002 } 1003 1004 static int netlink_setsockopt(struct socket *sock, int level, int optname, 1005 char __user *optval, int optlen) 1006 { 1007 struct sock *sk = sock->sk; 1008 struct netlink_sock *nlk = nlk_sk(sk); 1009 int val = 0, err; 1010 1011 if (level != SOL_NETLINK) 1012 return -ENOPROTOOPT; 1013 1014 if (optlen >= sizeof(int) && 1015 get_user(val, (int __user *)optval)) 1016 return -EFAULT; 1017 1018 switch (optname) { 1019 case NETLINK_PKTINFO: 1020 if (val) 1021 nlk->flags |= NETLINK_RECV_PKTINFO; 1022 else 1023 nlk->flags &= ~NETLINK_RECV_PKTINFO; 1024 err = 0; 1025 break; 1026 case NETLINK_ADD_MEMBERSHIP: 1027 case NETLINK_DROP_MEMBERSHIP: { 1028 unsigned int subscriptions; 1029 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0; 1030 1031 if (!netlink_capable(sock, NL_NONROOT_RECV)) 1032 return -EPERM; 1033 if (nlk->groups == NULL) { 1034 err = netlink_alloc_groups(sk); 1035 if (err) 1036 return err; 1037 } 1038 if (!val || val - 1 >= nlk->ngroups) 1039 return -EINVAL; 1040 netlink_table_grab(); 1041 old = test_bit(val - 1, nlk->groups); 1042 subscriptions = nlk->subscriptions - old + new; 1043 if (new) 1044 __set_bit(val - 1, nlk->groups); 1045 else 1046 __clear_bit(val - 1, nlk->groups); 1047 netlink_update_subscriptions(sk, subscriptions); 1048 netlink_update_listeners(sk); 1049 netlink_table_ungrab(); 1050 err = 0; 1051 break; 1052 } 1053 default: 1054 err = -ENOPROTOOPT; 1055 } 1056 return err; 1057 } 1058 1059 static int netlink_getsockopt(struct socket *sock, int level, int optname, 1060 char __user *optval, int __user *optlen) 1061 { 1062 struct sock *sk = sock->sk; 1063 struct netlink_sock *nlk = nlk_sk(sk); 1064 int len, val, err; 1065 1066 if (level != SOL_NETLINK) 1067 return -ENOPROTOOPT; 1068 1069 if (get_user(len, optlen)) 1070 return -EFAULT; 1071 if (len < 0) 1072 return -EINVAL; 1073 1074 switch (optname) { 1075 case NETLINK_PKTINFO: 1076 if (len < sizeof(int)) 1077 return -EINVAL; 1078 len = sizeof(int); 1079 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0; 1080 put_user(len, optlen); 1081 put_user(val, optval); 1082 err = 0; 1083 break; 1084 default: 1085 err = -ENOPROTOOPT; 1086 } 1087 return err; 1088 } 1089 1090 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1091 { 1092 struct nl_pktinfo info; 1093 1094 info.group = NETLINK_CB(skb).dst_group; 1095 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1096 } 1097 1098 static inline void netlink_rcv_wake(struct sock *sk) 1099 { 1100 struct netlink_sock *nlk = nlk_sk(sk); 1101 1102 if (skb_queue_empty(&sk->sk_receive_queue)) 1103 clear_bit(0, &nlk->state); 1104 if (!test_bit(0, &nlk->state)) 1105 wake_up_interruptible(&nlk->wait); 1106 } 1107 1108 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock, 1109 struct msghdr *msg, size_t len) 1110 { 1111 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1112 struct sock *sk = sock->sk; 1113 struct netlink_sock *nlk = nlk_sk(sk); 1114 struct sockaddr_nl *addr=msg->msg_name; 1115 u32 dst_pid; 1116 u32 dst_group; 1117 struct sk_buff *skb; 1118 int err; 1119 struct scm_cookie scm; 1120 1121 if (msg->msg_flags&MSG_OOB) 1122 return -EOPNOTSUPP; 1123 1124 if (NULL == siocb->scm) 1125 siocb->scm = &scm; 1126 err = scm_send(sock, msg, siocb->scm); 1127 if (err < 0) 1128 return err; 1129 1130 if (msg->msg_namelen) { 1131 if (addr->nl_family != AF_NETLINK) 1132 return -EINVAL; 1133 dst_pid = addr->nl_pid; 1134 dst_group = ffs(addr->nl_groups); 1135 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND)) 1136 return -EPERM; 1137 } else { 1138 dst_pid = nlk->dst_pid; 1139 dst_group = nlk->dst_group; 1140 } 1141 1142 if (!nlk->pid) { 1143 err = netlink_autobind(sock); 1144 if (err) 1145 goto out; 1146 } 1147 1148 err = -EMSGSIZE; 1149 if (len > sk->sk_sndbuf - 32) 1150 goto out; 1151 err = -ENOBUFS; 1152 skb = alloc_skb(len, GFP_KERNEL); 1153 if (skb==NULL) 1154 goto out; 1155 1156 NETLINK_CB(skb).pid = nlk->pid; 1157 NETLINK_CB(skb).dst_pid = dst_pid; 1158 NETLINK_CB(skb).dst_group = dst_group; 1159 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context); 1160 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid)); 1161 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1162 1163 /* What can I do? Netlink is asynchronous, so that 1164 we will have to save current capabilities to 1165 check them, when this message will be delivered 1166 to corresponding kernel module. --ANK (980802) 1167 */ 1168 1169 err = -EFAULT; 1170 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) { 1171 kfree_skb(skb); 1172 goto out; 1173 } 1174 1175 err = security_netlink_send(sk, skb); 1176 if (err) { 1177 kfree_skb(skb); 1178 goto out; 1179 } 1180 1181 if (dst_group) { 1182 atomic_inc(&skb->users); 1183 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL); 1184 } 1185 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT); 1186 1187 out: 1188 return err; 1189 } 1190 1191 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, 1192 struct msghdr *msg, size_t len, 1193 int flags) 1194 { 1195 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1196 struct scm_cookie scm; 1197 struct sock *sk = sock->sk; 1198 struct netlink_sock *nlk = nlk_sk(sk); 1199 int noblock = flags&MSG_DONTWAIT; 1200 size_t copied; 1201 struct sk_buff *skb; 1202 int err; 1203 1204 if (flags&MSG_OOB) 1205 return -EOPNOTSUPP; 1206 1207 copied = 0; 1208 1209 skb = skb_recv_datagram(sk,flags,noblock,&err); 1210 if (skb==NULL) 1211 goto out; 1212 1213 msg->msg_namelen = 0; 1214 1215 copied = skb->len; 1216 if (len < copied) { 1217 msg->msg_flags |= MSG_TRUNC; 1218 copied = len; 1219 } 1220 1221 skb->h.raw = skb->data; 1222 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); 1223 1224 if (msg->msg_name) { 1225 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name; 1226 addr->nl_family = AF_NETLINK; 1227 addr->nl_pad = 0; 1228 addr->nl_pid = NETLINK_CB(skb).pid; 1229 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1230 msg->msg_namelen = sizeof(*addr); 1231 } 1232 1233 if (nlk->flags & NETLINK_RECV_PKTINFO) 1234 netlink_cmsg_recv_pktinfo(msg, skb); 1235 1236 if (NULL == siocb->scm) { 1237 memset(&scm, 0, sizeof(scm)); 1238 siocb->scm = &scm; 1239 } 1240 siocb->scm->creds = *NETLINK_CREDS(skb); 1241 skb_free_datagram(sk, skb); 1242 1243 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) 1244 netlink_dump(sk); 1245 1246 scm_recv(sock, msg, siocb->scm, flags); 1247 1248 out: 1249 netlink_rcv_wake(sk); 1250 return err ? : copied; 1251 } 1252 1253 static void netlink_data_ready(struct sock *sk, int len) 1254 { 1255 struct netlink_sock *nlk = nlk_sk(sk); 1256 1257 if (nlk->data_ready) 1258 nlk->data_ready(sk, len); 1259 netlink_rcv_wake(sk); 1260 } 1261 1262 /* 1263 * We export these functions to other modules. They provide a 1264 * complete set of kernel non-blocking support for message 1265 * queueing. 1266 */ 1267 1268 struct sock * 1269 netlink_kernel_create(int unit, unsigned int groups, 1270 void (*input)(struct sock *sk, int len), 1271 struct module *module) 1272 { 1273 struct socket *sock; 1274 struct sock *sk; 1275 struct netlink_sock *nlk; 1276 unsigned long *listeners = NULL; 1277 1278 if (!nl_table) 1279 return NULL; 1280 1281 if (unit<0 || unit>=MAX_LINKS) 1282 return NULL; 1283 1284 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 1285 return NULL; 1286 1287 if (__netlink_create(sock, unit) < 0) 1288 goto out_sock_release; 1289 1290 if (groups < 32) 1291 groups = 32; 1292 1293 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL); 1294 if (!listeners) 1295 goto out_sock_release; 1296 1297 sk = sock->sk; 1298 sk->sk_data_ready = netlink_data_ready; 1299 if (input) 1300 nlk_sk(sk)->data_ready = input; 1301 1302 if (netlink_insert(sk, 0)) 1303 goto out_sock_release; 1304 1305 nlk = nlk_sk(sk); 1306 nlk->flags |= NETLINK_KERNEL_SOCKET; 1307 1308 netlink_table_grab(); 1309 nl_table[unit].groups = groups; 1310 nl_table[unit].listeners = listeners; 1311 nl_table[unit].module = module; 1312 nl_table[unit].registered = 1; 1313 netlink_table_ungrab(); 1314 1315 return sk; 1316 1317 out_sock_release: 1318 kfree(listeners); 1319 sock_release(sock); 1320 return NULL; 1321 } 1322 1323 void netlink_set_nonroot(int protocol, unsigned int flags) 1324 { 1325 if ((unsigned int)protocol < MAX_LINKS) 1326 nl_table[protocol].nl_nonroot = flags; 1327 } 1328 1329 static void netlink_destroy_callback(struct netlink_callback *cb) 1330 { 1331 if (cb->skb) 1332 kfree_skb(cb->skb); 1333 kfree(cb); 1334 } 1335 1336 /* 1337 * It looks a bit ugly. 1338 * It would be better to create kernel thread. 1339 */ 1340 1341 static int netlink_dump(struct sock *sk) 1342 { 1343 struct netlink_sock *nlk = nlk_sk(sk); 1344 struct netlink_callback *cb; 1345 struct sk_buff *skb; 1346 struct nlmsghdr *nlh; 1347 int len; 1348 1349 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL); 1350 if (!skb) 1351 return -ENOBUFS; 1352 1353 spin_lock(&nlk->cb_lock); 1354 1355 cb = nlk->cb; 1356 if (cb == NULL) { 1357 spin_unlock(&nlk->cb_lock); 1358 kfree_skb(skb); 1359 return -EINVAL; 1360 } 1361 1362 len = cb->dump(skb, cb); 1363 1364 if (len > 0) { 1365 spin_unlock(&nlk->cb_lock); 1366 skb_queue_tail(&sk->sk_receive_queue, skb); 1367 sk->sk_data_ready(sk, len); 1368 return 0; 1369 } 1370 1371 nlh = NLMSG_NEW_ANSWER(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); 1372 memcpy(NLMSG_DATA(nlh), &len, sizeof(len)); 1373 skb_queue_tail(&sk->sk_receive_queue, skb); 1374 sk->sk_data_ready(sk, skb->len); 1375 1376 if (cb->done) 1377 cb->done(cb); 1378 nlk->cb = NULL; 1379 spin_unlock(&nlk->cb_lock); 1380 1381 netlink_destroy_callback(cb); 1382 return 0; 1383 1384 nlmsg_failure: 1385 return -ENOBUFS; 1386 } 1387 1388 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 1389 struct nlmsghdr *nlh, 1390 int (*dump)(struct sk_buff *skb, struct netlink_callback*), 1391 int (*done)(struct netlink_callback*)) 1392 { 1393 struct netlink_callback *cb; 1394 struct sock *sk; 1395 struct netlink_sock *nlk; 1396 1397 cb = kmalloc(sizeof(*cb), GFP_KERNEL); 1398 if (cb == NULL) 1399 return -ENOBUFS; 1400 1401 memset(cb, 0, sizeof(*cb)); 1402 cb->dump = dump; 1403 cb->done = done; 1404 cb->nlh = nlh; 1405 atomic_inc(&skb->users); 1406 cb->skb = skb; 1407 1408 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid); 1409 if (sk == NULL) { 1410 netlink_destroy_callback(cb); 1411 return -ECONNREFUSED; 1412 } 1413 nlk = nlk_sk(sk); 1414 /* A dump is in progress... */ 1415 spin_lock(&nlk->cb_lock); 1416 if (nlk->cb) { 1417 spin_unlock(&nlk->cb_lock); 1418 netlink_destroy_callback(cb); 1419 sock_put(sk); 1420 return -EBUSY; 1421 } 1422 nlk->cb = cb; 1423 spin_unlock(&nlk->cb_lock); 1424 1425 netlink_dump(sk); 1426 sock_put(sk); 1427 return 0; 1428 } 1429 1430 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) 1431 { 1432 struct sk_buff *skb; 1433 struct nlmsghdr *rep; 1434 struct nlmsgerr *errmsg; 1435 int size; 1436 1437 if (err == 0) 1438 size = NLMSG_SPACE(sizeof(struct nlmsgerr)); 1439 else 1440 size = NLMSG_SPACE(4 + NLMSG_ALIGN(nlh->nlmsg_len)); 1441 1442 skb = alloc_skb(size, GFP_KERNEL); 1443 if (!skb) { 1444 struct sock *sk; 1445 1446 sk = netlink_lookup(in_skb->sk->sk_protocol, 1447 NETLINK_CB(in_skb).pid); 1448 if (sk) { 1449 sk->sk_err = ENOBUFS; 1450 sk->sk_error_report(sk); 1451 sock_put(sk); 1452 } 1453 return; 1454 } 1455 1456 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, 1457 NLMSG_ERROR, sizeof(struct nlmsgerr), 0); 1458 errmsg = NLMSG_DATA(rep); 1459 errmsg->error = err; 1460 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(struct nlmsghdr)); 1461 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT); 1462 } 1463 1464 static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 1465 struct nlmsghdr *, int *)) 1466 { 1467 unsigned int total_len; 1468 struct nlmsghdr *nlh; 1469 int err; 1470 1471 while (skb->len >= nlmsg_total_size(0)) { 1472 nlh = (struct nlmsghdr *) skb->data; 1473 1474 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 1475 return 0; 1476 1477 total_len = min(NLMSG_ALIGN(nlh->nlmsg_len), skb->len); 1478 1479 if (cb(skb, nlh, &err) < 0) { 1480 /* Not an error, but we have to interrupt processing 1481 * here. Note: that in this case we do not pull 1482 * message from skb, it will be processed later. 1483 */ 1484 if (err == 0) 1485 return -1; 1486 netlink_ack(skb, nlh, err); 1487 } else if (nlh->nlmsg_flags & NLM_F_ACK) 1488 netlink_ack(skb, nlh, 0); 1489 1490 skb_pull(skb, total_len); 1491 } 1492 1493 return 0; 1494 } 1495 1496 /** 1497 * nelink_run_queue - Process netlink receive queue. 1498 * @sk: Netlink socket containing the queue 1499 * @qlen: Place to store queue length upon entry 1500 * @cb: Callback function invoked for each netlink message found 1501 * 1502 * Processes as much as there was in the queue upon entry and invokes 1503 * a callback function for each netlink message found. The callback 1504 * function may refuse a message by returning a negative error code 1505 * but setting the error pointer to 0 in which case this function 1506 * returns with a qlen != 0. 1507 * 1508 * qlen must be initialized to 0 before the initial entry, afterwards 1509 * the function may be called repeatedly until qlen reaches 0. 1510 */ 1511 void netlink_run_queue(struct sock *sk, unsigned int *qlen, 1512 int (*cb)(struct sk_buff *, struct nlmsghdr *, int *)) 1513 { 1514 struct sk_buff *skb; 1515 1516 if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue)) 1517 *qlen = skb_queue_len(&sk->sk_receive_queue); 1518 1519 for (; *qlen; (*qlen)--) { 1520 skb = skb_dequeue(&sk->sk_receive_queue); 1521 if (netlink_rcv_skb(skb, cb)) { 1522 if (skb->len) 1523 skb_queue_head(&sk->sk_receive_queue, skb); 1524 else { 1525 kfree_skb(skb); 1526 (*qlen)--; 1527 } 1528 break; 1529 } 1530 1531 kfree_skb(skb); 1532 } 1533 } 1534 1535 /** 1536 * netlink_queue_skip - Skip netlink message while processing queue. 1537 * @nlh: Netlink message to be skipped 1538 * @skb: Socket buffer containing the netlink messages. 1539 * 1540 * Pulls the given netlink message off the socket buffer so the next 1541 * call to netlink_queue_run() will not reconsider the message. 1542 */ 1543 void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb) 1544 { 1545 int msglen = NLMSG_ALIGN(nlh->nlmsg_len); 1546 1547 if (msglen > skb->len) 1548 msglen = skb->len; 1549 1550 skb_pull(skb, msglen); 1551 } 1552 1553 #ifdef CONFIG_PROC_FS 1554 struct nl_seq_iter { 1555 int link; 1556 int hash_idx; 1557 }; 1558 1559 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos) 1560 { 1561 struct nl_seq_iter *iter = seq->private; 1562 int i, j; 1563 struct sock *s; 1564 struct hlist_node *node; 1565 loff_t off = 0; 1566 1567 for (i=0; i<MAX_LINKS; i++) { 1568 struct nl_pid_hash *hash = &nl_table[i].hash; 1569 1570 for (j = 0; j <= hash->mask; j++) { 1571 sk_for_each(s, node, &hash->table[j]) { 1572 if (off == pos) { 1573 iter->link = i; 1574 iter->hash_idx = j; 1575 return s; 1576 } 1577 ++off; 1578 } 1579 } 1580 } 1581 return NULL; 1582 } 1583 1584 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos) 1585 { 1586 read_lock(&nl_table_lock); 1587 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN; 1588 } 1589 1590 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1591 { 1592 struct sock *s; 1593 struct nl_seq_iter *iter; 1594 int i, j; 1595 1596 ++*pos; 1597 1598 if (v == SEQ_START_TOKEN) 1599 return netlink_seq_socket_idx(seq, 0); 1600 1601 s = sk_next(v); 1602 if (s) 1603 return s; 1604 1605 iter = seq->private; 1606 i = iter->link; 1607 j = iter->hash_idx + 1; 1608 1609 do { 1610 struct nl_pid_hash *hash = &nl_table[i].hash; 1611 1612 for (; j <= hash->mask; j++) { 1613 s = sk_head(&hash->table[j]); 1614 if (s) { 1615 iter->link = i; 1616 iter->hash_idx = j; 1617 return s; 1618 } 1619 } 1620 1621 j = 0; 1622 } while (++i < MAX_LINKS); 1623 1624 return NULL; 1625 } 1626 1627 static void netlink_seq_stop(struct seq_file *seq, void *v) 1628 { 1629 read_unlock(&nl_table_lock); 1630 } 1631 1632 1633 static int netlink_seq_show(struct seq_file *seq, void *v) 1634 { 1635 if (v == SEQ_START_TOKEN) 1636 seq_puts(seq, 1637 "sk Eth Pid Groups " 1638 "Rmem Wmem Dump Locks\n"); 1639 else { 1640 struct sock *s = v; 1641 struct netlink_sock *nlk = nlk_sk(s); 1642 1643 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n", 1644 s, 1645 s->sk_protocol, 1646 nlk->pid, 1647 nlk->groups ? (u32)nlk->groups[0] : 0, 1648 atomic_read(&s->sk_rmem_alloc), 1649 atomic_read(&s->sk_wmem_alloc), 1650 nlk->cb, 1651 atomic_read(&s->sk_refcnt) 1652 ); 1653 1654 } 1655 return 0; 1656 } 1657 1658 static struct seq_operations netlink_seq_ops = { 1659 .start = netlink_seq_start, 1660 .next = netlink_seq_next, 1661 .stop = netlink_seq_stop, 1662 .show = netlink_seq_show, 1663 }; 1664 1665 1666 static int netlink_seq_open(struct inode *inode, struct file *file) 1667 { 1668 struct seq_file *seq; 1669 struct nl_seq_iter *iter; 1670 int err; 1671 1672 iter = kmalloc(sizeof(*iter), GFP_KERNEL); 1673 if (!iter) 1674 return -ENOMEM; 1675 1676 err = seq_open(file, &netlink_seq_ops); 1677 if (err) { 1678 kfree(iter); 1679 return err; 1680 } 1681 1682 memset(iter, 0, sizeof(*iter)); 1683 seq = file->private_data; 1684 seq->private = iter; 1685 return 0; 1686 } 1687 1688 static struct file_operations netlink_seq_fops = { 1689 .owner = THIS_MODULE, 1690 .open = netlink_seq_open, 1691 .read = seq_read, 1692 .llseek = seq_lseek, 1693 .release = seq_release_private, 1694 }; 1695 1696 #endif 1697 1698 int netlink_register_notifier(struct notifier_block *nb) 1699 { 1700 return atomic_notifier_chain_register(&netlink_chain, nb); 1701 } 1702 1703 int netlink_unregister_notifier(struct notifier_block *nb) 1704 { 1705 return atomic_notifier_chain_unregister(&netlink_chain, nb); 1706 } 1707 1708 static const struct proto_ops netlink_ops = { 1709 .family = PF_NETLINK, 1710 .owner = THIS_MODULE, 1711 .release = netlink_release, 1712 .bind = netlink_bind, 1713 .connect = netlink_connect, 1714 .socketpair = sock_no_socketpair, 1715 .accept = sock_no_accept, 1716 .getname = netlink_getname, 1717 .poll = datagram_poll, 1718 .ioctl = sock_no_ioctl, 1719 .listen = sock_no_listen, 1720 .shutdown = sock_no_shutdown, 1721 .setsockopt = netlink_setsockopt, 1722 .getsockopt = netlink_getsockopt, 1723 .sendmsg = netlink_sendmsg, 1724 .recvmsg = netlink_recvmsg, 1725 .mmap = sock_no_mmap, 1726 .sendpage = sock_no_sendpage, 1727 }; 1728 1729 static struct net_proto_family netlink_family_ops = { 1730 .family = PF_NETLINK, 1731 .create = netlink_create, 1732 .owner = THIS_MODULE, /* for consistency 8) */ 1733 }; 1734 1735 extern void netlink_skb_parms_too_large(void); 1736 1737 static int __init netlink_proto_init(void) 1738 { 1739 struct sk_buff *dummy_skb; 1740 int i; 1741 unsigned long max; 1742 unsigned int order; 1743 int err = proto_register(&netlink_proto, 0); 1744 1745 if (err != 0) 1746 goto out; 1747 1748 if (sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb)) 1749 netlink_skb_parms_too_large(); 1750 1751 nl_table = kmalloc(sizeof(*nl_table) * MAX_LINKS, GFP_KERNEL); 1752 if (!nl_table) { 1753 enomem: 1754 printk(KERN_CRIT "netlink_init: Cannot allocate nl_table\n"); 1755 return -ENOMEM; 1756 } 1757 1758 memset(nl_table, 0, sizeof(*nl_table) * MAX_LINKS); 1759 1760 if (num_physpages >= (128 * 1024)) 1761 max = num_physpages >> (21 - PAGE_SHIFT); 1762 else 1763 max = num_physpages >> (23 - PAGE_SHIFT); 1764 1765 order = get_bitmask_order(max) - 1 + PAGE_SHIFT; 1766 max = (1UL << order) / sizeof(struct hlist_head); 1767 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1; 1768 1769 for (i = 0; i < MAX_LINKS; i++) { 1770 struct nl_pid_hash *hash = &nl_table[i].hash; 1771 1772 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table)); 1773 if (!hash->table) { 1774 while (i-- > 0) 1775 nl_pid_hash_free(nl_table[i].hash.table, 1776 1 * sizeof(*hash->table)); 1777 kfree(nl_table); 1778 goto enomem; 1779 } 1780 memset(hash->table, 0, 1 * sizeof(*hash->table)); 1781 hash->max_shift = order; 1782 hash->shift = 0; 1783 hash->mask = 0; 1784 hash->rehash_time = jiffies; 1785 } 1786 1787 sock_register(&netlink_family_ops); 1788 #ifdef CONFIG_PROC_FS 1789 proc_net_fops_create("netlink", 0, &netlink_seq_fops); 1790 #endif 1791 /* The netlink device handler may be needed early. */ 1792 rtnetlink_init(); 1793 out: 1794 return err; 1795 } 1796 1797 core_initcall(netlink_proto_init); 1798 1799 EXPORT_SYMBOL(netlink_ack); 1800 EXPORT_SYMBOL(netlink_run_queue); 1801 EXPORT_SYMBOL(netlink_queue_skip); 1802 EXPORT_SYMBOL(netlink_broadcast); 1803 EXPORT_SYMBOL(netlink_dump_start); 1804 EXPORT_SYMBOL(netlink_kernel_create); 1805 EXPORT_SYMBOL(netlink_register_notifier); 1806 EXPORT_SYMBOL(netlink_set_err); 1807 EXPORT_SYMBOL(netlink_set_nonroot); 1808 EXPORT_SYMBOL(netlink_unicast); 1809 EXPORT_SYMBOL(netlink_unregister_notifier); 1810 1811