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 module_put(nlk->module); 476 477 netlink_table_grab(); 478 if (nlk->flags & NETLINK_KERNEL_SOCKET) { 479 kfree(nl_table[sk->sk_protocol].listeners); 480 nl_table[sk->sk_protocol].module = NULL; 481 nl_table[sk->sk_protocol].registered = 0; 482 } else if (nlk->subscriptions) 483 netlink_update_listeners(sk); 484 netlink_table_ungrab(); 485 486 kfree(nlk->groups); 487 nlk->groups = NULL; 488 489 sock_put(sk); 490 return 0; 491 } 492 493 static int netlink_autobind(struct socket *sock) 494 { 495 struct sock *sk = sock->sk; 496 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 497 struct hlist_head *head; 498 struct sock *osk; 499 struct hlist_node *node; 500 s32 pid = current->tgid; 501 int err; 502 static s32 rover = -4097; 503 504 retry: 505 cond_resched(); 506 netlink_table_grab(); 507 head = nl_pid_hashfn(hash, pid); 508 sk_for_each(osk, node, head) { 509 if (nlk_sk(osk)->pid == pid) { 510 /* Bind collision, search negative pid values. */ 511 pid = rover--; 512 if (rover > -4097) 513 rover = -4097; 514 netlink_table_ungrab(); 515 goto retry; 516 } 517 } 518 netlink_table_ungrab(); 519 520 err = netlink_insert(sk, pid); 521 if (err == -EADDRINUSE) 522 goto retry; 523 524 /* If 2 threads race to autobind, that is fine. */ 525 if (err == -EBUSY) 526 err = 0; 527 528 return err; 529 } 530 531 static inline int netlink_capable(struct socket *sock, unsigned int flag) 532 { 533 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) || 534 capable(CAP_NET_ADMIN); 535 } 536 537 static void 538 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 539 { 540 struct netlink_sock *nlk = nlk_sk(sk); 541 542 if (nlk->subscriptions && !subscriptions) 543 __sk_del_bind_node(sk); 544 else if (!nlk->subscriptions && subscriptions) 545 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 546 nlk->subscriptions = subscriptions; 547 } 548 549 static int netlink_alloc_groups(struct sock *sk) 550 { 551 struct netlink_sock *nlk = nlk_sk(sk); 552 unsigned int groups; 553 int err = 0; 554 555 netlink_lock_table(); 556 groups = nl_table[sk->sk_protocol].groups; 557 if (!nl_table[sk->sk_protocol].registered) 558 err = -ENOENT; 559 netlink_unlock_table(); 560 561 if (err) 562 return err; 563 564 nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL); 565 if (nlk->groups == NULL) 566 return -ENOMEM; 567 nlk->ngroups = groups; 568 return 0; 569 } 570 571 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len) 572 { 573 struct sock *sk = sock->sk; 574 struct netlink_sock *nlk = nlk_sk(sk); 575 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 576 int err; 577 578 if (nladdr->nl_family != AF_NETLINK) 579 return -EINVAL; 580 581 /* Only superuser is allowed to listen multicasts */ 582 if (nladdr->nl_groups) { 583 if (!netlink_capable(sock, NL_NONROOT_RECV)) 584 return -EPERM; 585 if (nlk->groups == NULL) { 586 err = netlink_alloc_groups(sk); 587 if (err) 588 return err; 589 } 590 } 591 592 if (nlk->pid) { 593 if (nladdr->nl_pid != nlk->pid) 594 return -EINVAL; 595 } else { 596 err = nladdr->nl_pid ? 597 netlink_insert(sk, nladdr->nl_pid) : 598 netlink_autobind(sock); 599 if (err) 600 return err; 601 } 602 603 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) 604 return 0; 605 606 netlink_table_grab(); 607 netlink_update_subscriptions(sk, nlk->subscriptions + 608 hweight32(nladdr->nl_groups) - 609 hweight32(nlk->groups[0])); 610 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups; 611 netlink_update_listeners(sk); 612 netlink_table_ungrab(); 613 614 return 0; 615 } 616 617 static int netlink_connect(struct socket *sock, struct sockaddr *addr, 618 int alen, int flags) 619 { 620 int err = 0; 621 struct sock *sk = sock->sk; 622 struct netlink_sock *nlk = nlk_sk(sk); 623 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr; 624 625 if (addr->sa_family == AF_UNSPEC) { 626 sk->sk_state = NETLINK_UNCONNECTED; 627 nlk->dst_pid = 0; 628 nlk->dst_group = 0; 629 return 0; 630 } 631 if (addr->sa_family != AF_NETLINK) 632 return -EINVAL; 633 634 /* Only superuser is allowed to send multicasts */ 635 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND)) 636 return -EPERM; 637 638 if (!nlk->pid) 639 err = netlink_autobind(sock); 640 641 if (err == 0) { 642 sk->sk_state = NETLINK_CONNECTED; 643 nlk->dst_pid = nladdr->nl_pid; 644 nlk->dst_group = ffs(nladdr->nl_groups); 645 } 646 647 return err; 648 } 649 650 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer) 651 { 652 struct sock *sk = sock->sk; 653 struct netlink_sock *nlk = nlk_sk(sk); 654 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr; 655 656 nladdr->nl_family = AF_NETLINK; 657 nladdr->nl_pad = 0; 658 *addr_len = sizeof(*nladdr); 659 660 if (peer) { 661 nladdr->nl_pid = nlk->dst_pid; 662 nladdr->nl_groups = netlink_group_mask(nlk->dst_group); 663 } else { 664 nladdr->nl_pid = nlk->pid; 665 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 666 } 667 return 0; 668 } 669 670 static void netlink_overrun(struct sock *sk) 671 { 672 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) { 673 sk->sk_err = ENOBUFS; 674 sk->sk_error_report(sk); 675 } 676 } 677 678 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid) 679 { 680 int protocol = ssk->sk_protocol; 681 struct sock *sock; 682 struct netlink_sock *nlk; 683 684 sock = netlink_lookup(protocol, pid); 685 if (!sock) 686 return ERR_PTR(-ECONNREFUSED); 687 688 /* Don't bother queuing skb if kernel socket has no input function */ 689 nlk = nlk_sk(sock); 690 if ((nlk->pid == 0 && !nlk->data_ready) || 691 (sock->sk_state == NETLINK_CONNECTED && 692 nlk->dst_pid != nlk_sk(ssk)->pid)) { 693 sock_put(sock); 694 return ERR_PTR(-ECONNREFUSED); 695 } 696 return sock; 697 } 698 699 struct sock *netlink_getsockbyfilp(struct file *filp) 700 { 701 struct inode *inode = filp->f_path.dentry->d_inode; 702 struct sock *sock; 703 704 if (!S_ISSOCK(inode->i_mode)) 705 return ERR_PTR(-ENOTSOCK); 706 707 sock = SOCKET_I(inode)->sk; 708 if (sock->sk_family != AF_NETLINK) 709 return ERR_PTR(-EINVAL); 710 711 sock_hold(sock); 712 return sock; 713 } 714 715 /* 716 * Attach a skb to a netlink socket. 717 * The caller must hold a reference to the destination socket. On error, the 718 * reference is dropped. The skb is not send to the destination, just all 719 * all error checks are performed and memory in the queue is reserved. 720 * Return values: 721 * < 0: error. skb freed, reference to sock dropped. 722 * 0: continue 723 * 1: repeat lookup - reference dropped while waiting for socket memory. 724 */ 725 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, 726 long timeo, struct sock *ssk) 727 { 728 struct netlink_sock *nlk; 729 730 nlk = nlk_sk(sk); 731 732 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 733 test_bit(0, &nlk->state)) { 734 DECLARE_WAITQUEUE(wait, current); 735 if (!timeo) { 736 if (!ssk || nlk_sk(ssk)->pid == 0) 737 netlink_overrun(sk); 738 sock_put(sk); 739 kfree_skb(skb); 740 return -EAGAIN; 741 } 742 743 __set_current_state(TASK_INTERRUPTIBLE); 744 add_wait_queue(&nlk->wait, &wait); 745 746 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 747 test_bit(0, &nlk->state)) && 748 !sock_flag(sk, SOCK_DEAD)) 749 timeo = schedule_timeout(timeo); 750 751 __set_current_state(TASK_RUNNING); 752 remove_wait_queue(&nlk->wait, &wait); 753 sock_put(sk); 754 755 if (signal_pending(current)) { 756 kfree_skb(skb); 757 return sock_intr_errno(timeo); 758 } 759 return 1; 760 } 761 skb_set_owner_r(skb, sk); 762 return 0; 763 } 764 765 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol) 766 { 767 int len = skb->len; 768 769 skb_queue_tail(&sk->sk_receive_queue, skb); 770 sk->sk_data_ready(sk, len); 771 sock_put(sk); 772 return len; 773 } 774 775 void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 776 { 777 kfree_skb(skb); 778 sock_put(sk); 779 } 780 781 static inline struct sk_buff *netlink_trim(struct sk_buff *skb, 782 gfp_t allocation) 783 { 784 int delta; 785 786 skb_orphan(skb); 787 788 delta = skb->end - skb->tail; 789 if (delta * 2 < skb->truesize) 790 return skb; 791 792 if (skb_shared(skb)) { 793 struct sk_buff *nskb = skb_clone(skb, allocation); 794 if (!nskb) 795 return skb; 796 kfree_skb(skb); 797 skb = nskb; 798 } 799 800 if (!pskb_expand_head(skb, 0, -delta, allocation)) 801 skb->truesize -= delta; 802 803 return skb; 804 } 805 806 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock) 807 { 808 struct sock *sk; 809 int err; 810 long timeo; 811 812 skb = netlink_trim(skb, gfp_any()); 813 814 timeo = sock_sndtimeo(ssk, nonblock); 815 retry: 816 sk = netlink_getsockbypid(ssk, pid); 817 if (IS_ERR(sk)) { 818 kfree_skb(skb); 819 return PTR_ERR(sk); 820 } 821 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk); 822 if (err == 1) 823 goto retry; 824 if (err) 825 return err; 826 827 return netlink_sendskb(sk, skb, ssk->sk_protocol); 828 } 829 830 int netlink_has_listeners(struct sock *sk, unsigned int group) 831 { 832 int res = 0; 833 834 BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET)); 835 if (group - 1 < nl_table[sk->sk_protocol].groups) 836 res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners); 837 return res; 838 } 839 EXPORT_SYMBOL_GPL(netlink_has_listeners); 840 841 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 842 { 843 struct netlink_sock *nlk = nlk_sk(sk); 844 845 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 846 !test_bit(0, &nlk->state)) { 847 skb_set_owner_r(skb, sk); 848 skb_queue_tail(&sk->sk_receive_queue, skb); 849 sk->sk_data_ready(sk, skb->len); 850 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf; 851 } 852 return -1; 853 } 854 855 struct netlink_broadcast_data { 856 struct sock *exclude_sk; 857 u32 pid; 858 u32 group; 859 int failure; 860 int congested; 861 int delivered; 862 gfp_t allocation; 863 struct sk_buff *skb, *skb2; 864 }; 865 866 static inline int do_one_broadcast(struct sock *sk, 867 struct netlink_broadcast_data *p) 868 { 869 struct netlink_sock *nlk = nlk_sk(sk); 870 int val; 871 872 if (p->exclude_sk == sk) 873 goto out; 874 875 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 876 !test_bit(p->group - 1, nlk->groups)) 877 goto out; 878 879 if (p->failure) { 880 netlink_overrun(sk); 881 goto out; 882 } 883 884 sock_hold(sk); 885 if (p->skb2 == NULL) { 886 if (skb_shared(p->skb)) { 887 p->skb2 = skb_clone(p->skb, p->allocation); 888 } else { 889 p->skb2 = skb_get(p->skb); 890 /* 891 * skb ownership may have been set when 892 * delivered to a previous socket. 893 */ 894 skb_orphan(p->skb2); 895 } 896 } 897 if (p->skb2 == NULL) { 898 netlink_overrun(sk); 899 /* Clone failed. Notify ALL listeners. */ 900 p->failure = 1; 901 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) { 902 netlink_overrun(sk); 903 } else { 904 p->congested |= val; 905 p->delivered = 1; 906 p->skb2 = NULL; 907 } 908 sock_put(sk); 909 910 out: 911 return 0; 912 } 913 914 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid, 915 u32 group, gfp_t allocation) 916 { 917 struct netlink_broadcast_data info; 918 struct hlist_node *node; 919 struct sock *sk; 920 921 skb = netlink_trim(skb, allocation); 922 923 info.exclude_sk = ssk; 924 info.pid = pid; 925 info.group = group; 926 info.failure = 0; 927 info.congested = 0; 928 info.delivered = 0; 929 info.allocation = allocation; 930 info.skb = skb; 931 info.skb2 = NULL; 932 933 /* While we sleep in clone, do not allow to change socket list */ 934 935 netlink_lock_table(); 936 937 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 938 do_one_broadcast(sk, &info); 939 940 kfree_skb(skb); 941 942 netlink_unlock_table(); 943 944 if (info.skb2) 945 kfree_skb(info.skb2); 946 947 if (info.delivered) { 948 if (info.congested && (allocation & __GFP_WAIT)) 949 yield(); 950 return 0; 951 } 952 if (info.failure) 953 return -ENOBUFS; 954 return -ESRCH; 955 } 956 957 struct netlink_set_err_data { 958 struct sock *exclude_sk; 959 u32 pid; 960 u32 group; 961 int code; 962 }; 963 964 static inline int do_one_set_err(struct sock *sk, 965 struct netlink_set_err_data *p) 966 { 967 struct netlink_sock *nlk = nlk_sk(sk); 968 969 if (sk == p->exclude_sk) 970 goto out; 971 972 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 973 !test_bit(p->group - 1, nlk->groups)) 974 goto out; 975 976 sk->sk_err = p->code; 977 sk->sk_error_report(sk); 978 out: 979 return 0; 980 } 981 982 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code) 983 { 984 struct netlink_set_err_data info; 985 struct hlist_node *node; 986 struct sock *sk; 987 988 info.exclude_sk = ssk; 989 info.pid = pid; 990 info.group = group; 991 info.code = code; 992 993 read_lock(&nl_table_lock); 994 995 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 996 do_one_set_err(sk, &info); 997 998 read_unlock(&nl_table_lock); 999 } 1000 1001 static int netlink_setsockopt(struct socket *sock, int level, int optname, 1002 char __user *optval, int optlen) 1003 { 1004 struct sock *sk = sock->sk; 1005 struct netlink_sock *nlk = nlk_sk(sk); 1006 int val = 0, err; 1007 1008 if (level != SOL_NETLINK) 1009 return -ENOPROTOOPT; 1010 1011 if (optlen >= sizeof(int) && 1012 get_user(val, (int __user *)optval)) 1013 return -EFAULT; 1014 1015 switch (optname) { 1016 case NETLINK_PKTINFO: 1017 if (val) 1018 nlk->flags |= NETLINK_RECV_PKTINFO; 1019 else 1020 nlk->flags &= ~NETLINK_RECV_PKTINFO; 1021 err = 0; 1022 break; 1023 case NETLINK_ADD_MEMBERSHIP: 1024 case NETLINK_DROP_MEMBERSHIP: { 1025 unsigned int subscriptions; 1026 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0; 1027 1028 if (!netlink_capable(sock, NL_NONROOT_RECV)) 1029 return -EPERM; 1030 if (nlk->groups == NULL) { 1031 err = netlink_alloc_groups(sk); 1032 if (err) 1033 return err; 1034 } 1035 if (!val || val - 1 >= nlk->ngroups) 1036 return -EINVAL; 1037 netlink_table_grab(); 1038 old = test_bit(val - 1, nlk->groups); 1039 subscriptions = nlk->subscriptions - old + new; 1040 if (new) 1041 __set_bit(val - 1, nlk->groups); 1042 else 1043 __clear_bit(val - 1, nlk->groups); 1044 netlink_update_subscriptions(sk, subscriptions); 1045 netlink_update_listeners(sk); 1046 netlink_table_ungrab(); 1047 err = 0; 1048 break; 1049 } 1050 default: 1051 err = -ENOPROTOOPT; 1052 } 1053 return err; 1054 } 1055 1056 static int netlink_getsockopt(struct socket *sock, int level, int optname, 1057 char __user *optval, int __user *optlen) 1058 { 1059 struct sock *sk = sock->sk; 1060 struct netlink_sock *nlk = nlk_sk(sk); 1061 int len, val, err; 1062 1063 if (level != SOL_NETLINK) 1064 return -ENOPROTOOPT; 1065 1066 if (get_user(len, optlen)) 1067 return -EFAULT; 1068 if (len < 0) 1069 return -EINVAL; 1070 1071 switch (optname) { 1072 case NETLINK_PKTINFO: 1073 if (len < sizeof(int)) 1074 return -EINVAL; 1075 len = sizeof(int); 1076 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0; 1077 if (put_user(len, optlen) || 1078 put_user(val, optval)) 1079 return -EFAULT; 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_group = dst_group; 1156 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context); 1157 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid)); 1158 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1159 1160 /* What can I do? Netlink is asynchronous, so that 1161 we will have to save current capabilities to 1162 check them, when this message will be delivered 1163 to corresponding kernel module. --ANK (980802) 1164 */ 1165 1166 err = -EFAULT; 1167 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) { 1168 kfree_skb(skb); 1169 goto out; 1170 } 1171 1172 err = security_netlink_send(sk, skb); 1173 if (err) { 1174 kfree_skb(skb); 1175 goto out; 1176 } 1177 1178 if (dst_group) { 1179 atomic_inc(&skb->users); 1180 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL); 1181 } 1182 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT); 1183 1184 out: 1185 return err; 1186 } 1187 1188 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, 1189 struct msghdr *msg, size_t len, 1190 int flags) 1191 { 1192 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1193 struct scm_cookie scm; 1194 struct sock *sk = sock->sk; 1195 struct netlink_sock *nlk = nlk_sk(sk); 1196 int noblock = flags&MSG_DONTWAIT; 1197 size_t copied; 1198 struct sk_buff *skb; 1199 int err; 1200 1201 if (flags&MSG_OOB) 1202 return -EOPNOTSUPP; 1203 1204 copied = 0; 1205 1206 skb = skb_recv_datagram(sk,flags,noblock,&err); 1207 if (skb==NULL) 1208 goto out; 1209 1210 msg->msg_namelen = 0; 1211 1212 copied = skb->len; 1213 if (len < copied) { 1214 msg->msg_flags |= MSG_TRUNC; 1215 copied = len; 1216 } 1217 1218 skb->h.raw = skb->data; 1219 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); 1220 1221 if (msg->msg_name) { 1222 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name; 1223 addr->nl_family = AF_NETLINK; 1224 addr->nl_pad = 0; 1225 addr->nl_pid = NETLINK_CB(skb).pid; 1226 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1227 msg->msg_namelen = sizeof(*addr); 1228 } 1229 1230 if (nlk->flags & NETLINK_RECV_PKTINFO) 1231 netlink_cmsg_recv_pktinfo(msg, skb); 1232 1233 if (NULL == siocb->scm) { 1234 memset(&scm, 0, sizeof(scm)); 1235 siocb->scm = &scm; 1236 } 1237 siocb->scm->creds = *NETLINK_CREDS(skb); 1238 skb_free_datagram(sk, skb); 1239 1240 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) 1241 netlink_dump(sk); 1242 1243 scm_recv(sock, msg, siocb->scm, flags); 1244 1245 out: 1246 netlink_rcv_wake(sk); 1247 return err ? : copied; 1248 } 1249 1250 static void netlink_data_ready(struct sock *sk, int len) 1251 { 1252 struct netlink_sock *nlk = nlk_sk(sk); 1253 1254 if (nlk->data_ready) 1255 nlk->data_ready(sk, len); 1256 netlink_rcv_wake(sk); 1257 } 1258 1259 /* 1260 * We export these functions to other modules. They provide a 1261 * complete set of kernel non-blocking support for message 1262 * queueing. 1263 */ 1264 1265 struct sock * 1266 netlink_kernel_create(int unit, unsigned int groups, 1267 void (*input)(struct sock *sk, int len), 1268 struct module *module) 1269 { 1270 struct socket *sock; 1271 struct sock *sk; 1272 struct netlink_sock *nlk; 1273 unsigned long *listeners = NULL; 1274 1275 BUG_ON(!nl_table); 1276 1277 if (unit<0 || unit>=MAX_LINKS) 1278 return NULL; 1279 1280 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 1281 return NULL; 1282 1283 if (__netlink_create(sock, unit) < 0) 1284 goto out_sock_release; 1285 1286 if (groups < 32) 1287 groups = 32; 1288 1289 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL); 1290 if (!listeners) 1291 goto out_sock_release; 1292 1293 sk = sock->sk; 1294 sk->sk_data_ready = netlink_data_ready; 1295 if (input) 1296 nlk_sk(sk)->data_ready = input; 1297 1298 if (netlink_insert(sk, 0)) 1299 goto out_sock_release; 1300 1301 nlk = nlk_sk(sk); 1302 nlk->flags |= NETLINK_KERNEL_SOCKET; 1303 1304 netlink_table_grab(); 1305 nl_table[unit].groups = groups; 1306 nl_table[unit].listeners = listeners; 1307 nl_table[unit].module = module; 1308 nl_table[unit].registered = 1; 1309 netlink_table_ungrab(); 1310 1311 return sk; 1312 1313 out_sock_release: 1314 kfree(listeners); 1315 sock_release(sock); 1316 return NULL; 1317 } 1318 1319 void netlink_set_nonroot(int protocol, unsigned int flags) 1320 { 1321 if ((unsigned int)protocol < MAX_LINKS) 1322 nl_table[protocol].nl_nonroot = flags; 1323 } 1324 1325 static void netlink_destroy_callback(struct netlink_callback *cb) 1326 { 1327 if (cb->skb) 1328 kfree_skb(cb->skb); 1329 kfree(cb); 1330 } 1331 1332 /* 1333 * It looks a bit ugly. 1334 * It would be better to create kernel thread. 1335 */ 1336 1337 static int netlink_dump(struct sock *sk) 1338 { 1339 struct netlink_sock *nlk = nlk_sk(sk); 1340 struct netlink_callback *cb; 1341 struct sk_buff *skb; 1342 struct nlmsghdr *nlh; 1343 int len, err = -ENOBUFS; 1344 1345 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL); 1346 if (!skb) 1347 goto errout; 1348 1349 spin_lock(&nlk->cb_lock); 1350 1351 cb = nlk->cb; 1352 if (cb == NULL) { 1353 err = -EINVAL; 1354 goto errout_skb; 1355 } 1356 1357 len = cb->dump(skb, cb); 1358 1359 if (len > 0) { 1360 spin_unlock(&nlk->cb_lock); 1361 skb_queue_tail(&sk->sk_receive_queue, skb); 1362 sk->sk_data_ready(sk, len); 1363 return 0; 1364 } 1365 1366 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); 1367 if (!nlh) 1368 goto errout_skb; 1369 1370 memcpy(nlmsg_data(nlh), &len, sizeof(len)); 1371 1372 skb_queue_tail(&sk->sk_receive_queue, skb); 1373 sk->sk_data_ready(sk, skb->len); 1374 1375 if (cb->done) 1376 cb->done(cb); 1377 nlk->cb = NULL; 1378 spin_unlock(&nlk->cb_lock); 1379 1380 netlink_destroy_callback(cb); 1381 return 0; 1382 1383 errout_skb: 1384 spin_unlock(&nlk->cb_lock); 1385 kfree_skb(skb); 1386 errout: 1387 return err; 1388 } 1389 1390 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 1391 struct nlmsghdr *nlh, 1392 int (*dump)(struct sk_buff *skb, struct netlink_callback*), 1393 int (*done)(struct netlink_callback*)) 1394 { 1395 struct netlink_callback *cb; 1396 struct sock *sk; 1397 struct netlink_sock *nlk; 1398 1399 cb = kzalloc(sizeof(*cb), GFP_KERNEL); 1400 if (cb == NULL) 1401 return -ENOBUFS; 1402 1403 cb->dump = dump; 1404 cb->done = done; 1405 cb->nlh = nlh; 1406 atomic_inc(&skb->users); 1407 cb->skb = skb; 1408 1409 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid); 1410 if (sk == NULL) { 1411 netlink_destroy_callback(cb); 1412 return -ECONNREFUSED; 1413 } 1414 nlk = nlk_sk(sk); 1415 /* A dump is in progress... */ 1416 spin_lock(&nlk->cb_lock); 1417 if (nlk->cb) { 1418 spin_unlock(&nlk->cb_lock); 1419 netlink_destroy_callback(cb); 1420 sock_put(sk); 1421 return -EBUSY; 1422 } 1423 nlk->cb = cb; 1424 spin_unlock(&nlk->cb_lock); 1425 1426 netlink_dump(sk); 1427 sock_put(sk); 1428 return 0; 1429 } 1430 1431 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) 1432 { 1433 struct sk_buff *skb; 1434 struct nlmsghdr *rep; 1435 struct nlmsgerr *errmsg; 1436 size_t payload = sizeof(*errmsg); 1437 1438 /* error messages get the original request appened */ 1439 if (err) 1440 payload += nlmsg_len(nlh); 1441 1442 skb = nlmsg_new(payload, 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(*nlh)); 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 struct nlmsghdr *nlh; 1468 int err; 1469 1470 while (skb->len >= nlmsg_total_size(0)) { 1471 nlh = (struct nlmsghdr *) skb->data; 1472 1473 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 1474 return 0; 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 netlink_queue_skip(nlh, skb); 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 /** 1551 * nlmsg_notify - send a notification netlink message 1552 * @sk: netlink socket to use 1553 * @skb: notification message 1554 * @pid: destination netlink pid for reports or 0 1555 * @group: destination multicast group or 0 1556 * @report: 1 to report back, 0 to disable 1557 * @flags: allocation flags 1558 */ 1559 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid, 1560 unsigned int group, int report, gfp_t flags) 1561 { 1562 int err = 0; 1563 1564 if (group) { 1565 int exclude_pid = 0; 1566 1567 if (report) { 1568 atomic_inc(&skb->users); 1569 exclude_pid = pid; 1570 } 1571 1572 /* errors reported via destination sk->sk_err */ 1573 nlmsg_multicast(sk, skb, exclude_pid, group, flags); 1574 } 1575 1576 if (report) 1577 err = nlmsg_unicast(sk, skb, pid); 1578 1579 return err; 1580 } 1581 1582 #ifdef CONFIG_PROC_FS 1583 struct nl_seq_iter { 1584 int link; 1585 int hash_idx; 1586 }; 1587 1588 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos) 1589 { 1590 struct nl_seq_iter *iter = seq->private; 1591 int i, j; 1592 struct sock *s; 1593 struct hlist_node *node; 1594 loff_t off = 0; 1595 1596 for (i=0; i<MAX_LINKS; i++) { 1597 struct nl_pid_hash *hash = &nl_table[i].hash; 1598 1599 for (j = 0; j <= hash->mask; j++) { 1600 sk_for_each(s, node, &hash->table[j]) { 1601 if (off == pos) { 1602 iter->link = i; 1603 iter->hash_idx = j; 1604 return s; 1605 } 1606 ++off; 1607 } 1608 } 1609 } 1610 return NULL; 1611 } 1612 1613 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos) 1614 { 1615 read_lock(&nl_table_lock); 1616 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN; 1617 } 1618 1619 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1620 { 1621 struct sock *s; 1622 struct nl_seq_iter *iter; 1623 int i, j; 1624 1625 ++*pos; 1626 1627 if (v == SEQ_START_TOKEN) 1628 return netlink_seq_socket_idx(seq, 0); 1629 1630 s = sk_next(v); 1631 if (s) 1632 return s; 1633 1634 iter = seq->private; 1635 i = iter->link; 1636 j = iter->hash_idx + 1; 1637 1638 do { 1639 struct nl_pid_hash *hash = &nl_table[i].hash; 1640 1641 for (; j <= hash->mask; j++) { 1642 s = sk_head(&hash->table[j]); 1643 if (s) { 1644 iter->link = i; 1645 iter->hash_idx = j; 1646 return s; 1647 } 1648 } 1649 1650 j = 0; 1651 } while (++i < MAX_LINKS); 1652 1653 return NULL; 1654 } 1655 1656 static void netlink_seq_stop(struct seq_file *seq, void *v) 1657 { 1658 read_unlock(&nl_table_lock); 1659 } 1660 1661 1662 static int netlink_seq_show(struct seq_file *seq, void *v) 1663 { 1664 if (v == SEQ_START_TOKEN) 1665 seq_puts(seq, 1666 "sk Eth Pid Groups " 1667 "Rmem Wmem Dump Locks\n"); 1668 else { 1669 struct sock *s = v; 1670 struct netlink_sock *nlk = nlk_sk(s); 1671 1672 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n", 1673 s, 1674 s->sk_protocol, 1675 nlk->pid, 1676 nlk->groups ? (u32)nlk->groups[0] : 0, 1677 atomic_read(&s->sk_rmem_alloc), 1678 atomic_read(&s->sk_wmem_alloc), 1679 nlk->cb, 1680 atomic_read(&s->sk_refcnt) 1681 ); 1682 1683 } 1684 return 0; 1685 } 1686 1687 static struct seq_operations netlink_seq_ops = { 1688 .start = netlink_seq_start, 1689 .next = netlink_seq_next, 1690 .stop = netlink_seq_stop, 1691 .show = netlink_seq_show, 1692 }; 1693 1694 1695 static int netlink_seq_open(struct inode *inode, struct file *file) 1696 { 1697 struct seq_file *seq; 1698 struct nl_seq_iter *iter; 1699 int err; 1700 1701 iter = kzalloc(sizeof(*iter), GFP_KERNEL); 1702 if (!iter) 1703 return -ENOMEM; 1704 1705 err = seq_open(file, &netlink_seq_ops); 1706 if (err) { 1707 kfree(iter); 1708 return err; 1709 } 1710 1711 seq = file->private_data; 1712 seq->private = iter; 1713 return 0; 1714 } 1715 1716 static const struct file_operations netlink_seq_fops = { 1717 .owner = THIS_MODULE, 1718 .open = netlink_seq_open, 1719 .read = seq_read, 1720 .llseek = seq_lseek, 1721 .release = seq_release_private, 1722 }; 1723 1724 #endif 1725 1726 int netlink_register_notifier(struct notifier_block *nb) 1727 { 1728 return atomic_notifier_chain_register(&netlink_chain, nb); 1729 } 1730 1731 int netlink_unregister_notifier(struct notifier_block *nb) 1732 { 1733 return atomic_notifier_chain_unregister(&netlink_chain, nb); 1734 } 1735 1736 static const struct proto_ops netlink_ops = { 1737 .family = PF_NETLINK, 1738 .owner = THIS_MODULE, 1739 .release = netlink_release, 1740 .bind = netlink_bind, 1741 .connect = netlink_connect, 1742 .socketpair = sock_no_socketpair, 1743 .accept = sock_no_accept, 1744 .getname = netlink_getname, 1745 .poll = datagram_poll, 1746 .ioctl = sock_no_ioctl, 1747 .listen = sock_no_listen, 1748 .shutdown = sock_no_shutdown, 1749 .setsockopt = netlink_setsockopt, 1750 .getsockopt = netlink_getsockopt, 1751 .sendmsg = netlink_sendmsg, 1752 .recvmsg = netlink_recvmsg, 1753 .mmap = sock_no_mmap, 1754 .sendpage = sock_no_sendpage, 1755 }; 1756 1757 static struct net_proto_family netlink_family_ops = { 1758 .family = PF_NETLINK, 1759 .create = netlink_create, 1760 .owner = THIS_MODULE, /* for consistency 8) */ 1761 }; 1762 1763 static int __init netlink_proto_init(void) 1764 { 1765 struct sk_buff *dummy_skb; 1766 int i; 1767 unsigned long max; 1768 unsigned int order; 1769 int err = proto_register(&netlink_proto, 0); 1770 1771 if (err != 0) 1772 goto out; 1773 1774 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb)); 1775 1776 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 1777 if (!nl_table) 1778 goto panic; 1779 1780 if (num_physpages >= (128 * 1024)) 1781 max = num_physpages >> (21 - PAGE_SHIFT); 1782 else 1783 max = num_physpages >> (23 - PAGE_SHIFT); 1784 1785 order = get_bitmask_order(max) - 1 + PAGE_SHIFT; 1786 max = (1UL << order) / sizeof(struct hlist_head); 1787 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1; 1788 1789 for (i = 0; i < MAX_LINKS; i++) { 1790 struct nl_pid_hash *hash = &nl_table[i].hash; 1791 1792 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table)); 1793 if (!hash->table) { 1794 while (i-- > 0) 1795 nl_pid_hash_free(nl_table[i].hash.table, 1796 1 * sizeof(*hash->table)); 1797 kfree(nl_table); 1798 goto panic; 1799 } 1800 memset(hash->table, 0, 1 * sizeof(*hash->table)); 1801 hash->max_shift = order; 1802 hash->shift = 0; 1803 hash->mask = 0; 1804 hash->rehash_time = jiffies; 1805 } 1806 1807 sock_register(&netlink_family_ops); 1808 #ifdef CONFIG_PROC_FS 1809 proc_net_fops_create("netlink", 0, &netlink_seq_fops); 1810 #endif 1811 /* The netlink device handler may be needed early. */ 1812 rtnetlink_init(); 1813 out: 1814 return err; 1815 panic: 1816 panic("netlink_init: Cannot allocate nl_table\n"); 1817 } 1818 1819 core_initcall(netlink_proto_init); 1820 1821 EXPORT_SYMBOL(netlink_ack); 1822 EXPORT_SYMBOL(netlink_run_queue); 1823 EXPORT_SYMBOL(netlink_queue_skip); 1824 EXPORT_SYMBOL(netlink_broadcast); 1825 EXPORT_SYMBOL(netlink_dump_start); 1826 EXPORT_SYMBOL(netlink_kernel_create); 1827 EXPORT_SYMBOL(netlink_register_notifier); 1828 EXPORT_SYMBOL(netlink_set_err); 1829 EXPORT_SYMBOL(netlink_set_nonroot); 1830 EXPORT_SYMBOL(netlink_unicast); 1831 EXPORT_SYMBOL(netlink_unregister_notifier); 1832 EXPORT_SYMBOL(nlmsg_notify); 1833