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