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/notifier.h> 49#include <linux/security.h> 50#include <linux/jhash.h> 51#include <linux/jiffies.h> 52#include <linux/random.h> 53#include <linux/bitops.h> 54#include <linux/mm.h> 55#include <linux/types.h> 56#include <linux/audit.h> 57#include <linux/selinux.h> 58#include <linux/mutex.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 66struct 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 struct mutex *cb_mutex; 80 struct mutex cb_def_mutex; 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 88static inline struct netlink_sock *nlk_sk(struct sock *sk) 89{ 90 return (struct netlink_sock *)sk; 91} 92 93struct 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 106struct 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 mutex *cb_mutex; 113 struct module *module; 114 int registered; 115}; 116 117static struct netlink_table *nl_table; 118 119static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); 120 121static int netlink_dump(struct sock *sk); 122static void netlink_destroy_callback(struct netlink_callback *cb); 123static void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb); 124 125static DEFINE_RWLOCK(nl_table_lock); 126static atomic_t nl_table_users = ATOMIC_INIT(0); 127 128static ATOMIC_NOTIFIER_HEAD(netlink_chain); 129 130static u32 netlink_group_mask(u32 group) 131{ 132 return group ? 1 << (group - 1) : 0; 133} 134 135static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid) 136{ 137 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask]; 138} 139 140static void netlink_sock_destruct(struct sock *sk) 141{ 142 struct netlink_sock *nlk = nlk_sk(sk); 143 144 if (nlk->cb) { 145 if (nlk->cb->done) 146 nlk->cb->done(nlk->cb); 147 netlink_destroy_callback(nlk->cb); 148 } 149 150 skb_queue_purge(&sk->sk_receive_queue); 151 152 if (!sock_flag(sk, SOCK_DEAD)) { 153 printk("Freeing alive netlink socket %p\n", sk); 154 return; 155 } 156 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc)); 157 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc)); 158 BUG_TRAP(!nlk_sk(sk)->groups); 159} 160 161/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP. 162 * Look, when several writers sleep and reader wakes them up, all but one 163 * immediately hit write lock and grab all the cpus. Exclusive sleep solves 164 * this, _but_ remember, it adds useless work on UP machines. 165 */ 166 167static void netlink_table_grab(void) 168{ 169 write_lock_irq(&nl_table_lock); 170 171 if (atomic_read(&nl_table_users)) { 172 DECLARE_WAITQUEUE(wait, current); 173 174 add_wait_queue_exclusive(&nl_table_wait, &wait); 175 for(;;) { 176 set_current_state(TASK_UNINTERRUPTIBLE); 177 if (atomic_read(&nl_table_users) == 0) 178 break; 179 write_unlock_irq(&nl_table_lock); 180 schedule(); 181 write_lock_irq(&nl_table_lock); 182 } 183 184 __set_current_state(TASK_RUNNING); 185 remove_wait_queue(&nl_table_wait, &wait); 186 } 187} 188 189static __inline__ void netlink_table_ungrab(void) 190{ 191 write_unlock_irq(&nl_table_lock); 192 wake_up(&nl_table_wait); 193} 194 195static __inline__ void 196netlink_lock_table(void) 197{ 198 /* read_lock() synchronizes us to netlink_table_grab */ 199 200 read_lock(&nl_table_lock); 201 atomic_inc(&nl_table_users); 202 read_unlock(&nl_table_lock); 203} 204 205static __inline__ void 206netlink_unlock_table(void) 207{ 208 if (atomic_dec_and_test(&nl_table_users)) 209 wake_up(&nl_table_wait); 210} 211 212static __inline__ struct sock *netlink_lookup(int protocol, u32 pid) 213{ 214 struct nl_pid_hash *hash = &nl_table[protocol].hash; 215 struct hlist_head *head; 216 struct sock *sk; 217 struct hlist_node *node; 218 219 read_lock(&nl_table_lock); 220 head = nl_pid_hashfn(hash, pid); 221 sk_for_each(sk, node, head) { 222 if (nlk_sk(sk)->pid == pid) { 223 sock_hold(sk); 224 goto found; 225 } 226 } 227 sk = NULL; 228found: 229 read_unlock(&nl_table_lock); 230 return sk; 231} 232 233static inline struct hlist_head *nl_pid_hash_alloc(size_t size) 234{ 235 if (size <= PAGE_SIZE) 236 return kmalloc(size, GFP_ATOMIC); 237 else 238 return (struct hlist_head *) 239 __get_free_pages(GFP_ATOMIC, get_order(size)); 240} 241 242static inline void nl_pid_hash_free(struct hlist_head *table, size_t size) 243{ 244 if (size <= PAGE_SIZE) 245 kfree(table); 246 else 247 free_pages((unsigned long)table, get_order(size)); 248} 249 250static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow) 251{ 252 unsigned int omask, mask, shift; 253 size_t osize, size; 254 struct hlist_head *otable, *table; 255 int i; 256 257 omask = mask = hash->mask; 258 osize = size = (mask + 1) * sizeof(*table); 259 shift = hash->shift; 260 261 if (grow) { 262 if (++shift > hash->max_shift) 263 return 0; 264 mask = mask * 2 + 1; 265 size *= 2; 266 } 267 268 table = nl_pid_hash_alloc(size); 269 if (!table) 270 return 0; 271 272 memset(table, 0, size); 273 otable = hash->table; 274 hash->table = table; 275 hash->mask = mask; 276 hash->shift = shift; 277 get_random_bytes(&hash->rnd, sizeof(hash->rnd)); 278 279 for (i = 0; i <= omask; i++) { 280 struct sock *sk; 281 struct hlist_node *node, *tmp; 282 283 sk_for_each_safe(sk, node, tmp, &otable[i]) 284 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid)); 285 } 286 287 nl_pid_hash_free(otable, osize); 288 hash->rehash_time = jiffies + 10 * 60 * HZ; 289 return 1; 290} 291 292static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len) 293{ 294 int avg = hash->entries >> hash->shift; 295 296 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1)) 297 return 1; 298 299 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) { 300 nl_pid_hash_rehash(hash, 0); 301 return 1; 302 } 303 304 return 0; 305} 306 307static const struct proto_ops netlink_ops; 308 309static void 310netlink_update_listeners(struct sock *sk) 311{ 312 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 313 struct hlist_node *node; 314 unsigned long mask; 315 unsigned int i; 316 317 for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) { 318 mask = 0; 319 sk_for_each_bound(sk, node, &tbl->mc_list) 320 mask |= nlk_sk(sk)->groups[i]; 321 tbl->listeners[i] = mask; 322 } 323 /* this function is only called with the netlink table "grabbed", which 324 * makes sure updates are visible before bind or setsockopt return. */ 325} 326 327static int netlink_insert(struct sock *sk, u32 pid) 328{ 329 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 330 struct hlist_head *head; 331 int err = -EADDRINUSE; 332 struct sock *osk; 333 struct hlist_node *node; 334 int len; 335 336 netlink_table_grab(); 337 head = nl_pid_hashfn(hash, pid); 338 len = 0; 339 sk_for_each(osk, node, head) { 340 if (nlk_sk(osk)->pid == pid) 341 break; 342 len++; 343 } 344 if (node) 345 goto err; 346 347 err = -EBUSY; 348 if (nlk_sk(sk)->pid) 349 goto err; 350 351 err = -ENOMEM; 352 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX)) 353 goto err; 354 355 if (len && nl_pid_hash_dilute(hash, len)) 356 head = nl_pid_hashfn(hash, pid); 357 hash->entries++; 358 nlk_sk(sk)->pid = pid; 359 sk_add_node(sk, head); 360 err = 0; 361 362err: 363 netlink_table_ungrab(); 364 return err; 365} 366 367static void netlink_remove(struct sock *sk) 368{ 369 netlink_table_grab(); 370 if (sk_del_node_init(sk)) 371 nl_table[sk->sk_protocol].hash.entries--; 372 if (nlk_sk(sk)->subscriptions) 373 __sk_del_bind_node(sk); 374 netlink_table_ungrab(); 375} 376 377static struct proto netlink_proto = { 378 .name = "NETLINK", 379 .owner = THIS_MODULE, 380 .obj_size = sizeof(struct netlink_sock), 381}; 382 383static int __netlink_create(struct socket *sock, struct mutex *cb_mutex, 384 int protocol) 385{ 386 struct sock *sk; 387 struct netlink_sock *nlk; 388 389 sock->ops = &netlink_ops; 390 391 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1); 392 if (!sk) 393 return -ENOMEM; 394 395 sock_init_data(sock, sk); 396 397 nlk = nlk_sk(sk); 398 if (cb_mutex) 399 nlk->cb_mutex = cb_mutex; 400 else { 401 nlk->cb_mutex = &nlk->cb_def_mutex; 402 mutex_init(nlk->cb_mutex); 403 } 404 init_waitqueue_head(&nlk->wait); 405 406 sk->sk_destruct = netlink_sock_destruct; 407 sk->sk_protocol = protocol; 408 return 0; 409} 410 411static int netlink_create(struct socket *sock, int protocol) 412{ 413 struct module *module = NULL; 414 struct mutex *cb_mutex; 415 struct netlink_sock *nlk; 416 int err = 0; 417 418 sock->state = SS_UNCONNECTED; 419 420 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) 421 return -ESOCKTNOSUPPORT; 422 423 if (protocol<0 || protocol >= MAX_LINKS) 424 return -EPROTONOSUPPORT; 425 426 netlink_lock_table(); 427#ifdef CONFIG_KMOD 428 if (!nl_table[protocol].registered) { 429 netlink_unlock_table(); 430 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); 431 netlink_lock_table(); 432 } 433#endif 434 if (nl_table[protocol].registered && 435 try_module_get(nl_table[protocol].module)) 436 module = nl_table[protocol].module; 437 cb_mutex = nl_table[protocol].cb_mutex; 438 netlink_unlock_table(); 439 440 if ((err = __netlink_create(sock, cb_mutex, protocol)) < 0) 441 goto out_module; 442 443 nlk = nlk_sk(sock->sk); 444 nlk->module = module; 445out: 446 return err; 447 448out_module: 449 module_put(module); 450 goto out; 451} 452 453static int netlink_release(struct socket *sock) 454{ 455 struct sock *sk = sock->sk; 456 struct netlink_sock *nlk; 457 458 if (!sk) 459 return 0; 460 461 netlink_remove(sk); 462 sock_orphan(sk); 463 nlk = nlk_sk(sk); 464 465 /* 466 * OK. Socket is unlinked, any packets that arrive now 467 * will be purged. 468 */ 469 470 sock->sk = NULL; 471 wake_up_interruptible_all(&nlk->wait); 472 473 skb_queue_purge(&sk->sk_write_queue); 474 475 if (nlk->pid && !nlk->subscriptions) { 476 struct netlink_notify n = { 477 .protocol = sk->sk_protocol, 478 .pid = nlk->pid, 479 }; 480 atomic_notifier_call_chain(&netlink_chain, 481 NETLINK_URELEASE, &n); 482 } 483 484 module_put(nlk->module); 485 486 netlink_table_grab(); 487 if (nlk->flags & NETLINK_KERNEL_SOCKET) { 488 kfree(nl_table[sk->sk_protocol].listeners); 489 nl_table[sk->sk_protocol].module = NULL; 490 nl_table[sk->sk_protocol].registered = 0; 491 } else if (nlk->subscriptions) 492 netlink_update_listeners(sk); 493 netlink_table_ungrab(); 494 495 kfree(nlk->groups); 496 nlk->groups = NULL; 497 498 sock_put(sk); 499 return 0; 500} 501 502static int netlink_autobind(struct socket *sock) 503{ 504 struct sock *sk = sock->sk; 505 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash; 506 struct hlist_head *head; 507 struct sock *osk; 508 struct hlist_node *node; 509 s32 pid = current->tgid; 510 int err; 511 static s32 rover = -4097; 512 513retry: 514 cond_resched(); 515 netlink_table_grab(); 516 head = nl_pid_hashfn(hash, pid); 517 sk_for_each(osk, node, head) { 518 if (nlk_sk(osk)->pid == pid) { 519 /* Bind collision, search negative pid values. */ 520 pid = rover--; 521 if (rover > -4097) 522 rover = -4097; 523 netlink_table_ungrab(); 524 goto retry; 525 } 526 } 527 netlink_table_ungrab(); 528 529 err = netlink_insert(sk, pid); 530 if (err == -EADDRINUSE) 531 goto retry; 532 533 /* If 2 threads race to autobind, that is fine. */ 534 if (err == -EBUSY) 535 err = 0; 536 537 return err; 538} 539 540static inline int netlink_capable(struct socket *sock, unsigned int flag) 541{ 542 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) || 543 capable(CAP_NET_ADMIN); 544} 545 546static void 547netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 548{ 549 struct netlink_sock *nlk = nlk_sk(sk); 550 551 if (nlk->subscriptions && !subscriptions) 552 __sk_del_bind_node(sk); 553 else if (!nlk->subscriptions && subscriptions) 554 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 555 nlk->subscriptions = subscriptions; 556} 557 558static int netlink_alloc_groups(struct sock *sk) 559{ 560 struct netlink_sock *nlk = nlk_sk(sk); 561 unsigned int groups; 562 int err = 0; 563 564 netlink_lock_table(); 565 groups = nl_table[sk->sk_protocol].groups; 566 if (!nl_table[sk->sk_protocol].registered) 567 err = -ENOENT; 568 netlink_unlock_table(); 569 570 if (err) 571 return err; 572 573 nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL); 574 if (nlk->groups == NULL) 575 return -ENOMEM; 576 nlk->ngroups = groups; 577 return 0; 578} 579 580static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len) 581{ 582 struct sock *sk = sock->sk; 583 struct netlink_sock *nlk = nlk_sk(sk); 584 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 585 int err; 586 587 if (nladdr->nl_family != AF_NETLINK) 588 return -EINVAL; 589 590 /* Only superuser is allowed to listen multicasts */ 591 if (nladdr->nl_groups) { 592 if (!netlink_capable(sock, NL_NONROOT_RECV)) 593 return -EPERM; 594 if (nlk->groups == NULL) { 595 err = netlink_alloc_groups(sk); 596 if (err) 597 return err; 598 } 599 } 600 601 if (nlk->pid) { 602 if (nladdr->nl_pid != nlk->pid) 603 return -EINVAL; 604 } else { 605 err = nladdr->nl_pid ? 606 netlink_insert(sk, nladdr->nl_pid) : 607 netlink_autobind(sock); 608 if (err) 609 return err; 610 } 611 612 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) 613 return 0; 614 615 netlink_table_grab(); 616 netlink_update_subscriptions(sk, nlk->subscriptions + 617 hweight32(nladdr->nl_groups) - 618 hweight32(nlk->groups[0])); 619 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups; 620 netlink_update_listeners(sk); 621 netlink_table_ungrab(); 622 623 return 0; 624} 625 626static int netlink_connect(struct socket *sock, struct sockaddr *addr, 627 int alen, int flags) 628{ 629 int err = 0; 630 struct sock *sk = sock->sk; 631 struct netlink_sock *nlk = nlk_sk(sk); 632 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr; 633 634 if (addr->sa_family == AF_UNSPEC) { 635 sk->sk_state = NETLINK_UNCONNECTED; 636 nlk->dst_pid = 0; 637 nlk->dst_group = 0; 638 return 0; 639 } 640 if (addr->sa_family != AF_NETLINK) 641 return -EINVAL; 642 643 /* Only superuser is allowed to send multicasts */ 644 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND)) 645 return -EPERM; 646 647 if (!nlk->pid) 648 err = netlink_autobind(sock); 649 650 if (err == 0) { 651 sk->sk_state = NETLINK_CONNECTED; 652 nlk->dst_pid = nladdr->nl_pid; 653 nlk->dst_group = ffs(nladdr->nl_groups); 654 } 655 656 return err; 657} 658 659static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer) 660{ 661 struct sock *sk = sock->sk; 662 struct netlink_sock *nlk = nlk_sk(sk); 663 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr; 664 665 nladdr->nl_family = AF_NETLINK; 666 nladdr->nl_pad = 0; 667 *addr_len = sizeof(*nladdr); 668 669 if (peer) { 670 nladdr->nl_pid = nlk->dst_pid; 671 nladdr->nl_groups = netlink_group_mask(nlk->dst_group); 672 } else { 673 nladdr->nl_pid = nlk->pid; 674 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 675 } 676 return 0; 677} 678 679static void netlink_overrun(struct sock *sk) 680{ 681 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) { 682 sk->sk_err = ENOBUFS; 683 sk->sk_error_report(sk); 684 } 685} 686 687static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid) 688{ 689 int protocol = ssk->sk_protocol; 690 struct sock *sock; 691 struct netlink_sock *nlk; 692 693 sock = netlink_lookup(protocol, pid); 694 if (!sock) 695 return ERR_PTR(-ECONNREFUSED); 696 697 /* Don't bother queuing skb if kernel socket has no input function */ 698 nlk = nlk_sk(sock); 699 if ((nlk->pid == 0 && !nlk->data_ready) || 700 (sock->sk_state == NETLINK_CONNECTED && 701 nlk->dst_pid != nlk_sk(ssk)->pid)) { 702 sock_put(sock); 703 return ERR_PTR(-ECONNREFUSED); 704 } 705 return sock; 706} 707 708struct sock *netlink_getsockbyfilp(struct file *filp) 709{ 710 struct inode *inode = filp->f_path.dentry->d_inode; 711 struct sock *sock; 712 713 if (!S_ISSOCK(inode->i_mode)) 714 return ERR_PTR(-ENOTSOCK); 715 716 sock = SOCKET_I(inode)->sk; 717 if (sock->sk_family != AF_NETLINK) 718 return ERR_PTR(-EINVAL); 719 720 sock_hold(sock); 721 return sock; 722} 723 724/* 725 * Attach a skb to a netlink socket. 726 * The caller must hold a reference to the destination socket. On error, the 727 * reference is dropped. The skb is not send to the destination, just all 728 * all error checks are performed and memory in the queue is reserved. 729 * Return values: 730 * < 0: error. skb freed, reference to sock dropped. 731 * 0: continue 732 * 1: repeat lookup - reference dropped while waiting for socket memory. 733 */ 734int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, 735 long timeo, struct sock *ssk) 736{ 737 struct netlink_sock *nlk; 738 739 nlk = nlk_sk(sk); 740 741 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 742 test_bit(0, &nlk->state)) { 743 DECLARE_WAITQUEUE(wait, current); 744 if (!timeo) { 745 if (!ssk || nlk_sk(ssk)->pid == 0) 746 netlink_overrun(sk); 747 sock_put(sk); 748 kfree_skb(skb); 749 return -EAGAIN; 750 } 751 752 __set_current_state(TASK_INTERRUPTIBLE); 753 add_wait_queue(&nlk->wait, &wait); 754 755 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 756 test_bit(0, &nlk->state)) && 757 !sock_flag(sk, SOCK_DEAD)) 758 timeo = schedule_timeout(timeo); 759 760 __set_current_state(TASK_RUNNING); 761 remove_wait_queue(&nlk->wait, &wait); 762 sock_put(sk); 763 764 if (signal_pending(current)) { 765 kfree_skb(skb); 766 return sock_intr_errno(timeo); 767 } 768 return 1; 769 } 770 skb_set_owner_r(skb, sk); 771 return 0; 772} 773 774int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol) 775{ 776 int len = skb->len; 777 778 skb_queue_tail(&sk->sk_receive_queue, skb); 779 sk->sk_data_ready(sk, len); 780 sock_put(sk); 781 return len; 782} 783 784void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 785{ 786 kfree_skb(skb); 787 sock_put(sk); 788} 789 790static inline struct sk_buff *netlink_trim(struct sk_buff *skb, 791 gfp_t allocation) 792{ 793 int delta; 794 795 skb_orphan(skb); 796 797 delta = skb->end - skb->tail; 798 if (delta * 2 < skb->truesize) 799 return skb; 800 801 if (skb_shared(skb)) { 802 struct sk_buff *nskb = skb_clone(skb, allocation); 803 if (!nskb) 804 return skb; 805 kfree_skb(skb); 806 skb = nskb; 807 } 808 809 if (!pskb_expand_head(skb, 0, -delta, allocation)) 810 skb->truesize -= delta; 811 812 return skb; 813} 814 815int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock) 816{ 817 struct sock *sk; 818 int err; 819 long timeo; 820 821 skb = netlink_trim(skb, gfp_any()); 822 823 timeo = sock_sndtimeo(ssk, nonblock); 824retry: 825 sk = netlink_getsockbypid(ssk, pid); 826 if (IS_ERR(sk)) { 827 kfree_skb(skb); 828 return PTR_ERR(sk); 829 } 830 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk); 831 if (err == 1) 832 goto retry; 833 if (err) 834 return err; 835 836 return netlink_sendskb(sk, skb, ssk->sk_protocol); 837} 838 839int netlink_has_listeners(struct sock *sk, unsigned int group) 840{ 841 int res = 0; 842 843 BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET)); 844 if (group - 1 < nl_table[sk->sk_protocol].groups) 845 res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners); 846 return res; 847} 848EXPORT_SYMBOL_GPL(netlink_has_listeners); 849 850static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 851{ 852 struct netlink_sock *nlk = nlk_sk(sk); 853 854 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 855 !test_bit(0, &nlk->state)) { 856 skb_set_owner_r(skb, sk); 857 skb_queue_tail(&sk->sk_receive_queue, skb); 858 sk->sk_data_ready(sk, skb->len); 859 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf; 860 } 861 return -1; 862} 863 864struct netlink_broadcast_data { 865 struct sock *exclude_sk; 866 u32 pid; 867 u32 group; 868 int failure; 869 int congested; 870 int delivered; 871 gfp_t allocation; 872 struct sk_buff *skb, *skb2; 873}; 874 875static inline int do_one_broadcast(struct sock *sk, 876 struct netlink_broadcast_data *p) 877{ 878 struct netlink_sock *nlk = nlk_sk(sk); 879 int val; 880 881 if (p->exclude_sk == sk) 882 goto out; 883 884 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 885 !test_bit(p->group - 1, nlk->groups)) 886 goto out; 887 888 if (p->failure) { 889 netlink_overrun(sk); 890 goto out; 891 } 892 893 sock_hold(sk); 894 if (p->skb2 == NULL) { 895 if (skb_shared(p->skb)) { 896 p->skb2 = skb_clone(p->skb, p->allocation); 897 } else { 898 p->skb2 = skb_get(p->skb); 899 /* 900 * skb ownership may have been set when 901 * delivered to a previous socket. 902 */ 903 skb_orphan(p->skb2); 904 } 905 } 906 if (p->skb2 == NULL) { 907 netlink_overrun(sk); 908 /* Clone failed. Notify ALL listeners. */ 909 p->failure = 1; 910 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) { 911 netlink_overrun(sk); 912 } else { 913 p->congested |= val; 914 p->delivered = 1; 915 p->skb2 = NULL; 916 } 917 sock_put(sk); 918 919out: 920 return 0; 921} 922 923int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid, 924 u32 group, gfp_t allocation) 925{ 926 struct netlink_broadcast_data info; 927 struct hlist_node *node; 928 struct sock *sk; 929 930 skb = netlink_trim(skb, allocation); 931 932 info.exclude_sk = ssk; 933 info.pid = pid; 934 info.group = group; 935 info.failure = 0; 936 info.congested = 0; 937 info.delivered = 0; 938 info.allocation = allocation; 939 info.skb = skb; 940 info.skb2 = NULL; 941 942 /* While we sleep in clone, do not allow to change socket list */ 943 944 netlink_lock_table(); 945 946 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 947 do_one_broadcast(sk, &info); 948 949 kfree_skb(skb); 950 951 netlink_unlock_table(); 952 953 if (info.skb2) 954 kfree_skb(info.skb2); 955 956 if (info.delivered) { 957 if (info.congested && (allocation & __GFP_WAIT)) 958 yield(); 959 return 0; 960 } 961 if (info.failure) 962 return -ENOBUFS; 963 return -ESRCH; 964} 965 966struct netlink_set_err_data { 967 struct sock *exclude_sk; 968 u32 pid; 969 u32 group; 970 int code; 971}; 972 973static inline int do_one_set_err(struct sock *sk, 974 struct netlink_set_err_data *p) 975{ 976 struct netlink_sock *nlk = nlk_sk(sk); 977 978 if (sk == p->exclude_sk) 979 goto out; 980 981 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups || 982 !test_bit(p->group - 1, nlk->groups)) 983 goto out; 984 985 sk->sk_err = p->code; 986 sk->sk_error_report(sk); 987out: 988 return 0; 989} 990 991void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code) 992{ 993 struct netlink_set_err_data info; 994 struct hlist_node *node; 995 struct sock *sk; 996 997 info.exclude_sk = ssk; 998 info.pid = pid; 999 info.group = group; 1000 info.code = code; 1001 1002 read_lock(&nl_table_lock); 1003 1004 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list) 1005 do_one_set_err(sk, &info); 1006 1007 read_unlock(&nl_table_lock); 1008} 1009 1010static int netlink_setsockopt(struct socket *sock, int level, int optname, 1011 char __user *optval, int optlen) 1012{ 1013 struct sock *sk = sock->sk; 1014 struct netlink_sock *nlk = nlk_sk(sk); 1015 int val = 0, err; 1016 1017 if (level != SOL_NETLINK) 1018 return -ENOPROTOOPT; 1019 1020 if (optlen >= sizeof(int) && 1021 get_user(val, (int __user *)optval)) 1022 return -EFAULT; 1023 1024 switch (optname) { 1025 case NETLINK_PKTINFO: 1026 if (val) 1027 nlk->flags |= NETLINK_RECV_PKTINFO; 1028 else 1029 nlk->flags &= ~NETLINK_RECV_PKTINFO; 1030 err = 0; 1031 break; 1032 case NETLINK_ADD_MEMBERSHIP: 1033 case NETLINK_DROP_MEMBERSHIP: { 1034 unsigned int subscriptions; 1035 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0; 1036 1037 if (!netlink_capable(sock, NL_NONROOT_RECV)) 1038 return -EPERM; 1039 if (nlk->groups == NULL) { 1040 err = netlink_alloc_groups(sk); 1041 if (err) 1042 return err; 1043 } 1044 if (!val || val - 1 >= nlk->ngroups) 1045 return -EINVAL; 1046 netlink_table_grab(); 1047 old = test_bit(val - 1, nlk->groups); 1048 subscriptions = nlk->subscriptions - old + new; 1049 if (new) 1050 __set_bit(val - 1, nlk->groups); 1051 else 1052 __clear_bit(val - 1, nlk->groups); 1053 netlink_update_subscriptions(sk, subscriptions); 1054 netlink_update_listeners(sk); 1055 netlink_table_ungrab(); 1056 err = 0; 1057 break; 1058 } 1059 default: 1060 err = -ENOPROTOOPT; 1061 } 1062 return err; 1063} 1064 1065static int netlink_getsockopt(struct socket *sock, int level, int optname, 1066 char __user *optval, int __user *optlen) 1067{ 1068 struct sock *sk = sock->sk; 1069 struct netlink_sock *nlk = nlk_sk(sk); 1070 int len, val, err; 1071 1072 if (level != SOL_NETLINK) 1073 return -ENOPROTOOPT; 1074 1075 if (get_user(len, optlen)) 1076 return -EFAULT; 1077 if (len < 0) 1078 return -EINVAL; 1079 1080 switch (optname) { 1081 case NETLINK_PKTINFO: 1082 if (len < sizeof(int)) 1083 return -EINVAL; 1084 len = sizeof(int); 1085 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0; 1086 if (put_user(len, optlen) || 1087 put_user(val, optval)) 1088 return -EFAULT; 1089 err = 0; 1090 break; 1091 default: 1092 err = -ENOPROTOOPT; 1093 } 1094 return err; 1095} 1096 1097static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1098{ 1099 struct nl_pktinfo info; 1100 1101 info.group = NETLINK_CB(skb).dst_group; 1102 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1103} 1104 1105static inline void netlink_rcv_wake(struct sock *sk) 1106{ 1107 struct netlink_sock *nlk = nlk_sk(sk); 1108 1109 if (skb_queue_empty(&sk->sk_receive_queue)) 1110 clear_bit(0, &nlk->state); 1111 if (!test_bit(0, &nlk->state)) 1112 wake_up_interruptible(&nlk->wait); 1113} 1114 1115static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock, 1116 struct msghdr *msg, size_t len) 1117{ 1118 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1119 struct sock *sk = sock->sk; 1120 struct netlink_sock *nlk = nlk_sk(sk); 1121 struct sockaddr_nl *addr=msg->msg_name; 1122 u32 dst_pid; 1123 u32 dst_group; 1124 struct sk_buff *skb; 1125 int err; 1126 struct scm_cookie scm; 1127 1128 if (msg->msg_flags&MSG_OOB) 1129 return -EOPNOTSUPP; 1130 1131 if (NULL == siocb->scm) 1132 siocb->scm = &scm; 1133 err = scm_send(sock, msg, siocb->scm); 1134 if (err < 0) 1135 return err; 1136 1137 if (msg->msg_namelen) { 1138 if (addr->nl_family != AF_NETLINK) 1139 return -EINVAL; 1140 dst_pid = addr->nl_pid; 1141 dst_group = ffs(addr->nl_groups); 1142 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND)) 1143 return -EPERM; 1144 } else { 1145 dst_pid = nlk->dst_pid; 1146 dst_group = nlk->dst_group; 1147 } 1148 1149 if (!nlk->pid) { 1150 err = netlink_autobind(sock); 1151 if (err) 1152 goto out; 1153 } 1154 1155 err = -EMSGSIZE; 1156 if (len > sk->sk_sndbuf - 32) 1157 goto out; 1158 err = -ENOBUFS; 1159 skb = alloc_skb(len, GFP_KERNEL); 1160 if (skb==NULL) 1161 goto out; 1162 1163 NETLINK_CB(skb).pid = nlk->pid; 1164 NETLINK_CB(skb).dst_group = dst_group; 1165 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context); 1166 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid)); 1167 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1168 1169 /* What can I do? Netlink is asynchronous, so that 1170 we will have to save current capabilities to 1171 check them, when this message will be delivered 1172 to corresponding kernel module. --ANK (980802) 1173 */ 1174 1175 err = -EFAULT; 1176 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) { 1177 kfree_skb(skb); 1178 goto out; 1179 } 1180 1181 err = security_netlink_send(sk, skb); 1182 if (err) { 1183 kfree_skb(skb); 1184 goto out; 1185 } 1186 1187 if (dst_group) { 1188 atomic_inc(&skb->users); 1189 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL); 1190 } 1191 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT); 1192 1193out: 1194 return err; 1195} 1196 1197static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, 1198 struct msghdr *msg, size_t len, 1199 int flags) 1200{ 1201 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1202 struct scm_cookie scm; 1203 struct sock *sk = sock->sk; 1204 struct netlink_sock *nlk = nlk_sk(sk); 1205 int noblock = flags&MSG_DONTWAIT; 1206 size_t copied; 1207 struct sk_buff *skb; 1208 int err; 1209 1210 if (flags&MSG_OOB) 1211 return -EOPNOTSUPP; 1212 1213 copied = 0; 1214 1215 skb = skb_recv_datagram(sk,flags,noblock,&err); 1216 if (skb==NULL) 1217 goto out; 1218 1219 msg->msg_namelen = 0; 1220 1221 copied = skb->len; 1222 if (len < copied) { 1223 msg->msg_flags |= MSG_TRUNC; 1224 copied = len; 1225 } 1226 1227 skb_reset_transport_header(skb); 1228 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); 1229 1230 if (msg->msg_name) { 1231 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name; 1232 addr->nl_family = AF_NETLINK; 1233 addr->nl_pad = 0; 1234 addr->nl_pid = NETLINK_CB(skb).pid; 1235 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1236 msg->msg_namelen = sizeof(*addr); 1237 } 1238 1239 if (nlk->flags & NETLINK_RECV_PKTINFO) 1240 netlink_cmsg_recv_pktinfo(msg, skb); 1241 1242 if (NULL == siocb->scm) { 1243 memset(&scm, 0, sizeof(scm)); 1244 siocb->scm = &scm; 1245 } 1246 siocb->scm->creds = *NETLINK_CREDS(skb); 1247 if (flags & MSG_TRUNC) 1248 copied = skb->len; 1249 skb_free_datagram(sk, skb); 1250 1251 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) 1252 netlink_dump(sk); 1253 1254 scm_recv(sock, msg, siocb->scm, flags); 1255out: 1256 netlink_rcv_wake(sk); 1257 return err ? : copied; 1258} 1259 1260static void netlink_data_ready(struct sock *sk, int len) 1261{ 1262 struct netlink_sock *nlk = nlk_sk(sk); 1263 1264 if (nlk->data_ready) 1265 nlk->data_ready(sk, len); 1266 netlink_rcv_wake(sk); 1267} 1268 1269/* 1270 * We export these functions to other modules. They provide a 1271 * complete set of kernel non-blocking support for message 1272 * queueing. 1273 */ 1274 1275struct sock * 1276netlink_kernel_create(int unit, unsigned int groups, 1277 void (*input)(struct sock *sk, int len), 1278 struct mutex *cb_mutex, struct module *module) 1279{ 1280 struct socket *sock; 1281 struct sock *sk; 1282 struct netlink_sock *nlk; 1283 unsigned long *listeners = NULL; 1284 1285 BUG_ON(!nl_table); 1286 1287 if (unit<0 || unit>=MAX_LINKS) 1288 return NULL; 1289 1290 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 1291 return NULL; 1292 1293 if (__netlink_create(sock, cb_mutex, unit) < 0) 1294 goto out_sock_release; 1295 1296 if (groups < 32) 1297 groups = 32; 1298 1299 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL); 1300 if (!listeners) 1301 goto out_sock_release; 1302 1303 sk = sock->sk; 1304 sk->sk_data_ready = netlink_data_ready; 1305 if (input) 1306 nlk_sk(sk)->data_ready = input; 1307 1308 if (netlink_insert(sk, 0)) 1309 goto out_sock_release; 1310 1311 nlk = nlk_sk(sk); 1312 nlk->flags |= NETLINK_KERNEL_SOCKET; 1313 1314 netlink_table_grab(); 1315 nl_table[unit].groups = groups; 1316 nl_table[unit].listeners = listeners; 1317 nl_table[unit].cb_mutex = cb_mutex; 1318 nl_table[unit].module = module; 1319 nl_table[unit].registered = 1; 1320 netlink_table_ungrab(); 1321 1322 return sk; 1323 1324out_sock_release: 1325 kfree(listeners); 1326 sock_release(sock); 1327 return NULL; 1328} 1329 1330void netlink_set_nonroot(int protocol, unsigned int flags) 1331{ 1332 if ((unsigned int)protocol < MAX_LINKS) 1333 nl_table[protocol].nl_nonroot = flags; 1334} 1335 1336static void netlink_destroy_callback(struct netlink_callback *cb) 1337{ 1338 if (cb->skb) 1339 kfree_skb(cb->skb); 1340 kfree(cb); 1341} 1342 1343/* 1344 * It looks a bit ugly. 1345 * It would be better to create kernel thread. 1346 */ 1347 1348static int netlink_dump(struct sock *sk) 1349{ 1350 struct netlink_sock *nlk = nlk_sk(sk); 1351 struct netlink_callback *cb; 1352 struct sk_buff *skb; 1353 struct nlmsghdr *nlh; 1354 int len, err = -ENOBUFS; 1355 1356 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL); 1357 if (!skb) 1358 goto errout; 1359 1360 mutex_lock(nlk->cb_mutex); 1361 1362 cb = nlk->cb; 1363 if (cb == NULL) { 1364 err = -EINVAL; 1365 goto errout_skb; 1366 } 1367 1368 len = cb->dump(skb, cb); 1369 1370 if (len > 0) { 1371 mutex_unlock(nlk->cb_mutex); 1372 skb_queue_tail(&sk->sk_receive_queue, skb); 1373 sk->sk_data_ready(sk, len); 1374 return 0; 1375 } 1376 1377 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); 1378 if (!nlh) 1379 goto errout_skb; 1380 1381 memcpy(nlmsg_data(nlh), &len, sizeof(len)); 1382 1383 skb_queue_tail(&sk->sk_receive_queue, skb); 1384 sk->sk_data_ready(sk, skb->len); 1385 1386 if (cb->done) 1387 cb->done(cb); 1388 nlk->cb = NULL; 1389 mutex_unlock(nlk->cb_mutex); 1390 1391 netlink_destroy_callback(cb); 1392 return 0; 1393 1394errout_skb: 1395 mutex_unlock(nlk->cb_mutex); 1396 kfree_skb(skb); 1397errout: 1398 return err; 1399} 1400 1401int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 1402 struct nlmsghdr *nlh, 1403 int (*dump)(struct sk_buff *skb, struct netlink_callback*), 1404 int (*done)(struct netlink_callback*)) 1405{ 1406 struct netlink_callback *cb; 1407 struct sock *sk; 1408 struct netlink_sock *nlk; 1409 1410 cb = kzalloc(sizeof(*cb), GFP_KERNEL); 1411 if (cb == NULL) 1412 return -ENOBUFS; 1413 1414 cb->dump = dump; 1415 cb->done = done; 1416 cb->nlh = nlh; 1417 atomic_inc(&skb->users); 1418 cb->skb = skb; 1419 1420 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid); 1421 if (sk == NULL) { 1422 netlink_destroy_callback(cb); 1423 return -ECONNREFUSED; 1424 } 1425 nlk = nlk_sk(sk); 1426 /* A dump is in progress... */ 1427 mutex_lock(nlk->cb_mutex); 1428 if (nlk->cb) { 1429 mutex_unlock(nlk->cb_mutex); 1430 netlink_destroy_callback(cb); 1431 sock_put(sk); 1432 return -EBUSY; 1433 } 1434 nlk->cb = cb; 1435 mutex_unlock(nlk->cb_mutex); 1436 1437 netlink_dump(sk); 1438 sock_put(sk); 1439 1440 /* We successfully started a dump, by returning -EINTR we 1441 * signal the queue mangement to interrupt processing of 1442 * any netlink messages so userspace gets a chance to read 1443 * the results. */ 1444 return -EINTR; 1445} 1446 1447void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) 1448{ 1449 struct sk_buff *skb; 1450 struct nlmsghdr *rep; 1451 struct nlmsgerr *errmsg; 1452 size_t payload = sizeof(*errmsg); 1453 1454 /* error messages get the original request appened */ 1455 if (err) 1456 payload += nlmsg_len(nlh); 1457 1458 skb = nlmsg_new(payload, GFP_KERNEL); 1459 if (!skb) { 1460 struct sock *sk; 1461 1462 sk = netlink_lookup(in_skb->sk->sk_protocol, 1463 NETLINK_CB(in_skb).pid); 1464 if (sk) { 1465 sk->sk_err = ENOBUFS; 1466 sk->sk_error_report(sk); 1467 sock_put(sk); 1468 } 1469 return; 1470 } 1471 1472 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, 1473 NLMSG_ERROR, sizeof(struct nlmsgerr), 0); 1474 errmsg = nlmsg_data(rep); 1475 errmsg->error = err; 1476 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh)); 1477 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT); 1478} 1479 1480static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 1481 struct nlmsghdr *)) 1482{ 1483 struct nlmsghdr *nlh; 1484 int err; 1485 1486 while (skb->len >= nlmsg_total_size(0)) { 1487 nlh = nlmsg_hdr(skb); 1488 err = 0; 1489 1490 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 1491 return 0; 1492 1493 /* Only requests are handled by the kernel */ 1494 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) 1495 goto skip; 1496 1497 /* Skip control messages */ 1498 if (nlh->nlmsg_type < NLMSG_MIN_TYPE) 1499 goto skip; 1500 1501 err = cb(skb, nlh); 1502 if (err == -EINTR) { 1503 /* Not an error, but we interrupt processing */ 1504 netlink_queue_skip(nlh, skb); 1505 return err; 1506 } 1507skip: 1508 if (nlh->nlmsg_flags & NLM_F_ACK || err) 1509 netlink_ack(skb, nlh, err); 1510 1511 netlink_queue_skip(nlh, skb); 1512 } 1513 1514 return 0; 1515} 1516 1517/** 1518 * nelink_run_queue - Process netlink receive queue. 1519 * @sk: Netlink socket containing the queue 1520 * @qlen: Place to store queue length upon entry 1521 * @cb: Callback function invoked for each netlink message found 1522 * 1523 * Processes as much as there was in the queue upon entry and invokes 1524 * a callback function for each netlink message found. The callback 1525 * function may refuse a message by returning a negative error code 1526 * but setting the error pointer to 0 in which case this function 1527 * returns with a qlen != 0. 1528 * 1529 * qlen must be initialized to 0 before the initial entry, afterwards 1530 * the function may be called repeatedly until qlen reaches 0. 1531 * 1532 * The callback function may return -EINTR to signal that processing 1533 * of netlink messages shall be interrupted. In this case the message 1534 * currently being processed will NOT be requeued onto the receive 1535 * queue. 1536 */ 1537void netlink_run_queue(struct sock *sk, unsigned int *qlen, 1538 int (*cb)(struct sk_buff *, struct nlmsghdr *)) 1539{ 1540 struct sk_buff *skb; 1541 1542 if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue)) 1543 *qlen = skb_queue_len(&sk->sk_receive_queue); 1544 1545 for (; *qlen; (*qlen)--) { 1546 skb = skb_dequeue(&sk->sk_receive_queue); 1547 if (netlink_rcv_skb(skb, cb)) { 1548 if (skb->len) 1549 skb_queue_head(&sk->sk_receive_queue, skb); 1550 else { 1551 kfree_skb(skb); 1552 (*qlen)--; 1553 } 1554 break; 1555 } 1556 1557 kfree_skb(skb); 1558 } 1559} 1560 1561/** 1562 * netlink_queue_skip - Skip netlink message while processing queue. 1563 * @nlh: Netlink message to be skipped 1564 * @skb: Socket buffer containing the netlink messages. 1565 * 1566 * Pulls the given netlink message off the socket buffer so the next 1567 * call to netlink_queue_run() will not reconsider the message. 1568 */ 1569static void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb) 1570{ 1571 int msglen = NLMSG_ALIGN(nlh->nlmsg_len); 1572 1573 if (msglen > skb->len) 1574 msglen = skb->len; 1575 1576 skb_pull(skb, msglen); 1577} 1578 1579/** 1580 * nlmsg_notify - send a notification netlink message 1581 * @sk: netlink socket to use 1582 * @skb: notification message 1583 * @pid: destination netlink pid for reports or 0 1584 * @group: destination multicast group or 0 1585 * @report: 1 to report back, 0 to disable 1586 * @flags: allocation flags 1587 */ 1588int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid, 1589 unsigned int group, int report, gfp_t flags) 1590{ 1591 int err = 0; 1592 1593 if (group) { 1594 int exclude_pid = 0; 1595 1596 if (report) { 1597 atomic_inc(&skb->users); 1598 exclude_pid = pid; 1599 } 1600 1601 /* errors reported via destination sk->sk_err */ 1602 nlmsg_multicast(sk, skb, exclude_pid, group, flags); 1603 } 1604 1605 if (report) 1606 err = nlmsg_unicast(sk, skb, pid); 1607 1608 return err; 1609} 1610 1611#ifdef CONFIG_PROC_FS 1612struct nl_seq_iter { 1613 int link; 1614 int hash_idx; 1615}; 1616 1617static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos) 1618{ 1619 struct nl_seq_iter *iter = seq->private; 1620 int i, j; 1621 struct sock *s; 1622 struct hlist_node *node; 1623 loff_t off = 0; 1624 1625 for (i=0; i<MAX_LINKS; i++) { 1626 struct nl_pid_hash *hash = &nl_table[i].hash; 1627 1628 for (j = 0; j <= hash->mask; j++) { 1629 sk_for_each(s, node, &hash->table[j]) { 1630 if (off == pos) { 1631 iter->link = i; 1632 iter->hash_idx = j; 1633 return s; 1634 } 1635 ++off; 1636 } 1637 } 1638 } 1639 return NULL; 1640} 1641 1642static void *netlink_seq_start(struct seq_file *seq, loff_t *pos) 1643{ 1644 read_lock(&nl_table_lock); 1645 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN; 1646} 1647 1648static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1649{ 1650 struct sock *s; 1651 struct nl_seq_iter *iter; 1652 int i, j; 1653 1654 ++*pos; 1655 1656 if (v == SEQ_START_TOKEN) 1657 return netlink_seq_socket_idx(seq, 0); 1658 1659 s = sk_next(v); 1660 if (s) 1661 return s; 1662 1663 iter = seq->private; 1664 i = iter->link; 1665 j = iter->hash_idx + 1; 1666 1667 do { 1668 struct nl_pid_hash *hash = &nl_table[i].hash; 1669 1670 for (; j <= hash->mask; j++) { 1671 s = sk_head(&hash->table[j]); 1672 if (s) { 1673 iter->link = i; 1674 iter->hash_idx = j; 1675 return s; 1676 } 1677 } 1678 1679 j = 0; 1680 } while (++i < MAX_LINKS); 1681 1682 return NULL; 1683} 1684 1685static void netlink_seq_stop(struct seq_file *seq, void *v) 1686{ 1687 read_unlock(&nl_table_lock); 1688} 1689 1690 1691static int netlink_seq_show(struct seq_file *seq, void *v) 1692{ 1693 if (v == SEQ_START_TOKEN) 1694 seq_puts(seq, 1695 "sk Eth Pid Groups " 1696 "Rmem Wmem Dump Locks\n"); 1697 else { 1698 struct sock *s = v; 1699 struct netlink_sock *nlk = nlk_sk(s); 1700 1701 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n", 1702 s, 1703 s->sk_protocol, 1704 nlk->pid, 1705 nlk->groups ? (u32)nlk->groups[0] : 0, 1706 atomic_read(&s->sk_rmem_alloc), 1707 atomic_read(&s->sk_wmem_alloc), 1708 nlk->cb, 1709 atomic_read(&s->sk_refcnt) 1710 ); 1711 1712 } 1713 return 0; 1714} 1715 1716static struct seq_operations netlink_seq_ops = { 1717 .start = netlink_seq_start, 1718 .next = netlink_seq_next, 1719 .stop = netlink_seq_stop, 1720 .show = netlink_seq_show, 1721}; 1722 1723 1724static int netlink_seq_open(struct inode *inode, struct file *file) 1725{ 1726 struct seq_file *seq; 1727 struct nl_seq_iter *iter; 1728 int err; 1729 1730 iter = kzalloc(sizeof(*iter), GFP_KERNEL); 1731 if (!iter) 1732 return -ENOMEM; 1733 1734 err = seq_open(file, &netlink_seq_ops); 1735 if (err) { 1736 kfree(iter); 1737 return err; 1738 } 1739 1740 seq = file->private_data; 1741 seq->private = iter; 1742 return 0; 1743} 1744 1745static const struct file_operations netlink_seq_fops = { 1746 .owner = THIS_MODULE, 1747 .open = netlink_seq_open, 1748 .read = seq_read, 1749 .llseek = seq_lseek, 1750 .release = seq_release_private, 1751}; 1752 1753#endif 1754 1755int netlink_register_notifier(struct notifier_block *nb) 1756{ 1757 return atomic_notifier_chain_register(&netlink_chain, nb); 1758} 1759 1760int netlink_unregister_notifier(struct notifier_block *nb) 1761{ 1762 return atomic_notifier_chain_unregister(&netlink_chain, nb); 1763} 1764 1765/* Foxconn added start pling 02/24/2011 */ 1766int netlink_ioctl(struct sock *sk, int cmd, unsigned long arg) 1767{ 1768 /* there are no netlink specific IOCTLs but if we have 1769 * the handler, the generic one will take of things 1770 * such as SIOCGIFNAME and SIOCGIFINDEX, etc. 1771 */ 1772 return -ENOIOCTLCMD; 1773} 1774/* Foxconn added end pling 02/24/2011 */ 1775 1776static const struct proto_ops netlink_ops = { 1777 .family = PF_NETLINK, 1778 .owner = THIS_MODULE, 1779 .release = netlink_release, 1780 .bind = netlink_bind, 1781 .connect = netlink_connect, 1782 .socketpair = sock_no_socketpair, 1783 .accept = sock_no_accept, 1784 .getname = netlink_getname, 1785 .poll = datagram_poll, 1786 /* Foxconn modified start pling 02/24/2011 */ 1787 /* For zeroconf (auto ip) */ 1788 /*.ioctl = sock_no_ioctl,*/ 1789 .ioctl = netlink_ioctl, 1790 /* Foxconn modified end pling 02/24/2011 */ 1791 .listen = sock_no_listen, 1792 .shutdown = sock_no_shutdown, 1793 .setsockopt = netlink_setsockopt, 1794 .getsockopt = netlink_getsockopt, 1795 .sendmsg = netlink_sendmsg, 1796 .recvmsg = netlink_recvmsg, 1797 .mmap = sock_no_mmap, 1798 .sendpage = sock_no_sendpage, 1799}; 1800 1801static struct net_proto_family netlink_family_ops = { 1802 .family = PF_NETLINK, 1803 .create = netlink_create, 1804 .owner = THIS_MODULE, /* for consistency 8) */ 1805}; 1806 1807static int __init netlink_proto_init(void) 1808{ 1809 struct sk_buff *dummy_skb; 1810 int i; 1811 unsigned long max; 1812 unsigned int order; 1813 int err = proto_register(&netlink_proto, 0); 1814 1815 if (err != 0) 1816 goto out; 1817 1818 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb)); 1819 1820 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 1821 if (!nl_table) 1822 goto panic; 1823 1824 if (num_physpages >= (128 * 1024)) 1825 max = num_physpages >> (21 - PAGE_SHIFT); 1826 else 1827 max = num_physpages >> (23 - PAGE_SHIFT); 1828 1829 order = get_bitmask_order(max) - 1 + PAGE_SHIFT; 1830 max = (1UL << order) / sizeof(struct hlist_head); 1831 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1; 1832 1833 for (i = 0; i < MAX_LINKS; i++) { 1834 struct nl_pid_hash *hash = &nl_table[i].hash; 1835 1836 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table)); 1837 if (!hash->table) { 1838 while (i-- > 0) 1839 nl_pid_hash_free(nl_table[i].hash.table, 1840 1 * sizeof(*hash->table)); 1841 kfree(nl_table); 1842 goto panic; 1843 } 1844 memset(hash->table, 0, 1 * sizeof(*hash->table)); 1845 hash->max_shift = order; 1846 hash->shift = 0; 1847 hash->mask = 0; 1848 hash->rehash_time = jiffies; 1849 } 1850 1851 sock_register(&netlink_family_ops); 1852#ifdef CONFIG_PROC_FS 1853 proc_net_fops_create("netlink", 0, &netlink_seq_fops); 1854#endif 1855 /* The netlink device handler may be needed early. */ 1856 rtnetlink_init(); 1857out: 1858 return err; 1859panic: 1860 panic("netlink_init: Cannot allocate nl_table\n"); 1861} 1862 1863core_initcall(netlink_proto_init); 1864 1865EXPORT_SYMBOL(netlink_ack); 1866EXPORT_SYMBOL(netlink_run_queue); 1867EXPORT_SYMBOL(netlink_broadcast); 1868EXPORT_SYMBOL(netlink_dump_start); 1869EXPORT_SYMBOL(netlink_kernel_create); 1870EXPORT_SYMBOL(netlink_register_notifier); 1871EXPORT_SYMBOL(netlink_set_nonroot); 1872EXPORT_SYMBOL(netlink_unicast); 1873EXPORT_SYMBOL(netlink_unregister_notifier); 1874EXPORT_SYMBOL(nlmsg_notify); 1875EXPORT_SYMBOL(netlink_ioctl); /* Foxconn added pling 02/24/2011 */ 1876