1 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 2 3 #include <linux/workqueue.h> 4 #include <linux/rtnetlink.h> 5 #include <linux/cache.h> 6 #include <linux/slab.h> 7 #include <linux/list.h> 8 #include <linux/delay.h> 9 #include <linux/sched.h> 10 #include <linux/idr.h> 11 #include <linux/rculist.h> 12 #include <linux/nsproxy.h> 13 #include <linux/fs.h> 14 #include <linux/proc_ns.h> 15 #include <linux/file.h> 16 #include <linux/export.h> 17 #include <linux/user_namespace.h> 18 #include <linux/net_namespace.h> 19 #include <net/sock.h> 20 #include <net/netlink.h> 21 #include <net/net_namespace.h> 22 #include <net/netns/generic.h> 23 24 /* 25 * Our network namespace constructor/destructor lists 26 */ 27 28 static LIST_HEAD(pernet_list); 29 static struct list_head *first_device = &pernet_list; 30 DEFINE_MUTEX(net_mutex); 31 32 LIST_HEAD(net_namespace_list); 33 EXPORT_SYMBOL_GPL(net_namespace_list); 34 35 struct net init_net = { 36 .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head), 37 }; 38 EXPORT_SYMBOL(init_net); 39 40 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */ 41 42 static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS; 43 44 static struct net_generic *net_alloc_generic(void) 45 { 46 struct net_generic *ng; 47 size_t generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]); 48 49 ng = kzalloc(generic_size, GFP_KERNEL); 50 if (ng) 51 ng->len = max_gen_ptrs; 52 53 return ng; 54 } 55 56 static int net_assign_generic(struct net *net, int id, void *data) 57 { 58 struct net_generic *ng, *old_ng; 59 60 BUG_ON(!mutex_is_locked(&net_mutex)); 61 BUG_ON(id == 0); 62 63 old_ng = rcu_dereference_protected(net->gen, 64 lockdep_is_held(&net_mutex)); 65 ng = old_ng; 66 if (old_ng->len >= id) 67 goto assign; 68 69 ng = net_alloc_generic(); 70 if (ng == NULL) 71 return -ENOMEM; 72 73 /* 74 * Some synchronisation notes: 75 * 76 * The net_generic explores the net->gen array inside rcu 77 * read section. Besides once set the net->gen->ptr[x] 78 * pointer never changes (see rules in netns/generic.h). 79 * 80 * That said, we simply duplicate this array and schedule 81 * the old copy for kfree after a grace period. 82 */ 83 84 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*)); 85 86 rcu_assign_pointer(net->gen, ng); 87 kfree_rcu(old_ng, rcu); 88 assign: 89 ng->ptr[id - 1] = data; 90 return 0; 91 } 92 93 static int ops_init(const struct pernet_operations *ops, struct net *net) 94 { 95 int err = -ENOMEM; 96 void *data = NULL; 97 98 if (ops->id && ops->size) { 99 data = kzalloc(ops->size, GFP_KERNEL); 100 if (!data) 101 goto out; 102 103 err = net_assign_generic(net, *ops->id, data); 104 if (err) 105 goto cleanup; 106 } 107 err = 0; 108 if (ops->init) 109 err = ops->init(net); 110 if (!err) 111 return 0; 112 113 cleanup: 114 kfree(data); 115 116 out: 117 return err; 118 } 119 120 static void ops_free(const struct pernet_operations *ops, struct net *net) 121 { 122 if (ops->id && ops->size) { 123 int id = *ops->id; 124 kfree(net_generic(net, id)); 125 } 126 } 127 128 static void ops_exit_list(const struct pernet_operations *ops, 129 struct list_head *net_exit_list) 130 { 131 struct net *net; 132 if (ops->exit) { 133 list_for_each_entry(net, net_exit_list, exit_list) 134 ops->exit(net); 135 } 136 if (ops->exit_batch) 137 ops->exit_batch(net_exit_list); 138 } 139 140 static void ops_free_list(const struct pernet_operations *ops, 141 struct list_head *net_exit_list) 142 { 143 struct net *net; 144 if (ops->size && ops->id) { 145 list_for_each_entry(net, net_exit_list, exit_list) 146 ops_free(ops, net); 147 } 148 } 149 150 static int alloc_netid(struct net *net, struct net *peer, int reqid) 151 { 152 int min = 0, max = 0; 153 154 ASSERT_RTNL(); 155 156 if (reqid >= 0) { 157 min = reqid; 158 max = reqid + 1; 159 } 160 161 return idr_alloc(&net->netns_ids, peer, min, max, GFP_KERNEL); 162 } 163 164 /* This function is used by idr_for_each(). If net is equal to peer, the 165 * function returns the id so that idr_for_each() stops. Because we cannot 166 * returns the id 0 (idr_for_each() will not stop), we return the magic value 167 * NET_ID_ZERO (-1) for it. 168 */ 169 #define NET_ID_ZERO -1 170 static int net_eq_idr(int id, void *net, void *peer) 171 { 172 if (net_eq(net, peer)) 173 return id ? : NET_ID_ZERO; 174 return 0; 175 } 176 177 static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc) 178 { 179 int id = idr_for_each(&net->netns_ids, net_eq_idr, peer); 180 bool alloc_it = *alloc; 181 182 ASSERT_RTNL(); 183 184 *alloc = false; 185 186 /* Magic value for id 0. */ 187 if (id == NET_ID_ZERO) 188 return 0; 189 if (id > 0) 190 return id; 191 192 if (alloc_it) { 193 id = alloc_netid(net, peer, -1); 194 *alloc = true; 195 return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED; 196 } 197 198 return NETNSA_NSID_NOT_ASSIGNED; 199 } 200 201 static int __peernet2id(struct net *net, struct net *peer) 202 { 203 bool no = false; 204 205 return __peernet2id_alloc(net, peer, &no); 206 } 207 208 static void rtnl_net_notifyid(struct net *net, int cmd, int id); 209 /* This function returns the id of a peer netns. If no id is assigned, one will 210 * be allocated and returned. 211 */ 212 int peernet2id_alloc(struct net *net, struct net *peer) 213 { 214 bool alloc = atomic_read(&peer->count) == 0 ? false : true; 215 int id; 216 217 id = __peernet2id_alloc(net, peer, &alloc); 218 if (alloc && id >= 0) 219 rtnl_net_notifyid(net, RTM_NEWNSID, id); 220 return id; 221 } 222 EXPORT_SYMBOL(peernet2id_alloc); 223 224 struct net *get_net_ns_by_id(struct net *net, int id) 225 { 226 struct net *peer; 227 228 if (id < 0) 229 return NULL; 230 231 rcu_read_lock(); 232 peer = idr_find(&net->netns_ids, id); 233 if (peer) 234 get_net(peer); 235 rcu_read_unlock(); 236 237 return peer; 238 } 239 240 /* 241 * setup_net runs the initializers for the network namespace object. 242 */ 243 static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) 244 { 245 /* Must be called with net_mutex held */ 246 const struct pernet_operations *ops, *saved_ops; 247 int error = 0; 248 LIST_HEAD(net_exit_list); 249 250 atomic_set(&net->count, 1); 251 atomic_set(&net->passive, 1); 252 net->dev_base_seq = 1; 253 net->user_ns = user_ns; 254 idr_init(&net->netns_ids); 255 256 list_for_each_entry(ops, &pernet_list, list) { 257 error = ops_init(ops, net); 258 if (error < 0) 259 goto out_undo; 260 } 261 out: 262 return error; 263 264 out_undo: 265 /* Walk through the list backwards calling the exit functions 266 * for the pernet modules whose init functions did not fail. 267 */ 268 list_add(&net->exit_list, &net_exit_list); 269 saved_ops = ops; 270 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 271 ops_exit_list(ops, &net_exit_list); 272 273 ops = saved_ops; 274 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 275 ops_free_list(ops, &net_exit_list); 276 277 rcu_barrier(); 278 goto out; 279 } 280 281 282 #ifdef CONFIG_NET_NS 283 static struct kmem_cache *net_cachep; 284 static struct workqueue_struct *netns_wq; 285 286 static struct net *net_alloc(void) 287 { 288 struct net *net = NULL; 289 struct net_generic *ng; 290 291 ng = net_alloc_generic(); 292 if (!ng) 293 goto out; 294 295 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL); 296 if (!net) 297 goto out_free; 298 299 rcu_assign_pointer(net->gen, ng); 300 out: 301 return net; 302 303 out_free: 304 kfree(ng); 305 goto out; 306 } 307 308 static void net_free(struct net *net) 309 { 310 kfree(rcu_access_pointer(net->gen)); 311 kmem_cache_free(net_cachep, net); 312 } 313 314 void net_drop_ns(void *p) 315 { 316 struct net *ns = p; 317 if (ns && atomic_dec_and_test(&ns->passive)) 318 net_free(ns); 319 } 320 321 struct net *copy_net_ns(unsigned long flags, 322 struct user_namespace *user_ns, struct net *old_net) 323 { 324 struct net *net; 325 int rv; 326 327 if (!(flags & CLONE_NEWNET)) 328 return get_net(old_net); 329 330 net = net_alloc(); 331 if (!net) 332 return ERR_PTR(-ENOMEM); 333 334 get_user_ns(user_ns); 335 336 mutex_lock(&net_mutex); 337 rv = setup_net(net, user_ns); 338 if (rv == 0) { 339 rtnl_lock(); 340 list_add_tail_rcu(&net->list, &net_namespace_list); 341 rtnl_unlock(); 342 } 343 mutex_unlock(&net_mutex); 344 if (rv < 0) { 345 put_user_ns(user_ns); 346 net_drop_ns(net); 347 return ERR_PTR(rv); 348 } 349 return net; 350 } 351 352 static DEFINE_SPINLOCK(cleanup_list_lock); 353 static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */ 354 355 static void cleanup_net(struct work_struct *work) 356 { 357 const struct pernet_operations *ops; 358 struct net *net, *tmp; 359 struct list_head net_kill_list; 360 LIST_HEAD(net_exit_list); 361 362 /* Atomically snapshot the list of namespaces to cleanup */ 363 spin_lock_irq(&cleanup_list_lock); 364 list_replace_init(&cleanup_list, &net_kill_list); 365 spin_unlock_irq(&cleanup_list_lock); 366 367 mutex_lock(&net_mutex); 368 369 /* Don't let anyone else find us. */ 370 rtnl_lock(); 371 list_for_each_entry(net, &net_kill_list, cleanup_list) { 372 list_del_rcu(&net->list); 373 list_add_tail(&net->exit_list, &net_exit_list); 374 for_each_net(tmp) { 375 int id = __peernet2id(tmp, net); 376 377 if (id >= 0) { 378 rtnl_net_notifyid(tmp, RTM_DELNSID, id); 379 idr_remove(&tmp->netns_ids, id); 380 } 381 } 382 idr_destroy(&net->netns_ids); 383 384 } 385 rtnl_unlock(); 386 387 /* 388 * Another CPU might be rcu-iterating the list, wait for it. 389 * This needs to be before calling the exit() notifiers, so 390 * the rcu_barrier() below isn't sufficient alone. 391 */ 392 synchronize_rcu(); 393 394 /* Run all of the network namespace exit methods */ 395 list_for_each_entry_reverse(ops, &pernet_list, list) 396 ops_exit_list(ops, &net_exit_list); 397 398 /* Free the net generic variables */ 399 list_for_each_entry_reverse(ops, &pernet_list, list) 400 ops_free_list(ops, &net_exit_list); 401 402 mutex_unlock(&net_mutex); 403 404 /* Ensure there are no outstanding rcu callbacks using this 405 * network namespace. 406 */ 407 rcu_barrier(); 408 409 /* Finally it is safe to free my network namespace structure */ 410 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { 411 list_del_init(&net->exit_list); 412 put_user_ns(net->user_ns); 413 net_drop_ns(net); 414 } 415 } 416 static DECLARE_WORK(net_cleanup_work, cleanup_net); 417 418 void __put_net(struct net *net) 419 { 420 /* Cleanup the network namespace in process context */ 421 unsigned long flags; 422 423 spin_lock_irqsave(&cleanup_list_lock, flags); 424 list_add(&net->cleanup_list, &cleanup_list); 425 spin_unlock_irqrestore(&cleanup_list_lock, flags); 426 427 queue_work(netns_wq, &net_cleanup_work); 428 } 429 EXPORT_SYMBOL_GPL(__put_net); 430 431 struct net *get_net_ns_by_fd(int fd) 432 { 433 struct file *file; 434 struct ns_common *ns; 435 struct net *net; 436 437 file = proc_ns_fget(fd); 438 if (IS_ERR(file)) 439 return ERR_CAST(file); 440 441 ns = get_proc_ns(file_inode(file)); 442 if (ns->ops == &netns_operations) 443 net = get_net(container_of(ns, struct net, ns)); 444 else 445 net = ERR_PTR(-EINVAL); 446 447 fput(file); 448 return net; 449 } 450 451 #else 452 struct net *get_net_ns_by_fd(int fd) 453 { 454 return ERR_PTR(-EINVAL); 455 } 456 #endif 457 EXPORT_SYMBOL_GPL(get_net_ns_by_fd); 458 459 struct net *get_net_ns_by_pid(pid_t pid) 460 { 461 struct task_struct *tsk; 462 struct net *net; 463 464 /* Lookup the network namespace */ 465 net = ERR_PTR(-ESRCH); 466 rcu_read_lock(); 467 tsk = find_task_by_vpid(pid); 468 if (tsk) { 469 struct nsproxy *nsproxy; 470 task_lock(tsk); 471 nsproxy = tsk->nsproxy; 472 if (nsproxy) 473 net = get_net(nsproxy->net_ns); 474 task_unlock(tsk); 475 } 476 rcu_read_unlock(); 477 return net; 478 } 479 EXPORT_SYMBOL_GPL(get_net_ns_by_pid); 480 481 static __net_init int net_ns_net_init(struct net *net) 482 { 483 #ifdef CONFIG_NET_NS 484 net->ns.ops = &netns_operations; 485 #endif 486 return ns_alloc_inum(&net->ns); 487 } 488 489 static __net_exit void net_ns_net_exit(struct net *net) 490 { 491 ns_free_inum(&net->ns); 492 } 493 494 static struct pernet_operations __net_initdata net_ns_ops = { 495 .init = net_ns_net_init, 496 .exit = net_ns_net_exit, 497 }; 498 499 static struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = { 500 [NETNSA_NONE] = { .type = NLA_UNSPEC }, 501 [NETNSA_NSID] = { .type = NLA_S32 }, 502 [NETNSA_PID] = { .type = NLA_U32 }, 503 [NETNSA_FD] = { .type = NLA_U32 }, 504 }; 505 506 static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh) 507 { 508 struct net *net = sock_net(skb->sk); 509 struct nlattr *tb[NETNSA_MAX + 1]; 510 struct net *peer; 511 int nsid, err; 512 513 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, 514 rtnl_net_policy); 515 if (err < 0) 516 return err; 517 if (!tb[NETNSA_NSID]) 518 return -EINVAL; 519 nsid = nla_get_s32(tb[NETNSA_NSID]); 520 521 if (tb[NETNSA_PID]) 522 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 523 else if (tb[NETNSA_FD]) 524 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 525 else 526 return -EINVAL; 527 if (IS_ERR(peer)) 528 return PTR_ERR(peer); 529 530 if (__peernet2id(net, peer) >= 0) { 531 err = -EEXIST; 532 goto out; 533 } 534 535 err = alloc_netid(net, peer, nsid); 536 if (err >= 0) { 537 rtnl_net_notifyid(net, RTM_NEWNSID, err); 538 err = 0; 539 } 540 out: 541 put_net(peer); 542 return err; 543 } 544 545 static int rtnl_net_get_size(void) 546 { 547 return NLMSG_ALIGN(sizeof(struct rtgenmsg)) 548 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */ 549 ; 550 } 551 552 static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags, 553 int cmd, struct net *net, int nsid) 554 { 555 struct nlmsghdr *nlh; 556 struct rtgenmsg *rth; 557 558 nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rth), flags); 559 if (!nlh) 560 return -EMSGSIZE; 561 562 rth = nlmsg_data(nlh); 563 rth->rtgen_family = AF_UNSPEC; 564 565 if (nla_put_s32(skb, NETNSA_NSID, nsid)) 566 goto nla_put_failure; 567 568 nlmsg_end(skb, nlh); 569 return 0; 570 571 nla_put_failure: 572 nlmsg_cancel(skb, nlh); 573 return -EMSGSIZE; 574 } 575 576 static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh) 577 { 578 struct net *net = sock_net(skb->sk); 579 struct nlattr *tb[NETNSA_MAX + 1]; 580 struct sk_buff *msg; 581 struct net *peer; 582 int err, id; 583 584 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, 585 rtnl_net_policy); 586 if (err < 0) 587 return err; 588 if (tb[NETNSA_PID]) 589 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 590 else if (tb[NETNSA_FD]) 591 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 592 else 593 return -EINVAL; 594 595 if (IS_ERR(peer)) 596 return PTR_ERR(peer); 597 598 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 599 if (!msg) { 600 err = -ENOMEM; 601 goto out; 602 } 603 604 id = __peernet2id(net, peer); 605 err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0, 606 RTM_GETNSID, net, id); 607 if (err < 0) 608 goto err_out; 609 610 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid); 611 goto out; 612 613 err_out: 614 nlmsg_free(msg); 615 out: 616 put_net(peer); 617 return err; 618 } 619 620 struct rtnl_net_dump_cb { 621 struct net *net; 622 struct sk_buff *skb; 623 struct netlink_callback *cb; 624 int idx; 625 int s_idx; 626 }; 627 628 static int rtnl_net_dumpid_one(int id, void *peer, void *data) 629 { 630 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data; 631 int ret; 632 633 if (net_cb->idx < net_cb->s_idx) 634 goto cont; 635 636 ret = rtnl_net_fill(net_cb->skb, NETLINK_CB(net_cb->cb->skb).portid, 637 net_cb->cb->nlh->nlmsg_seq, NLM_F_MULTI, 638 RTM_NEWNSID, net_cb->net, id); 639 if (ret < 0) 640 return ret; 641 642 cont: 643 net_cb->idx++; 644 return 0; 645 } 646 647 static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb) 648 { 649 struct net *net = sock_net(skb->sk); 650 struct rtnl_net_dump_cb net_cb = { 651 .net = net, 652 .skb = skb, 653 .cb = cb, 654 .idx = 0, 655 .s_idx = cb->args[0], 656 }; 657 658 ASSERT_RTNL(); 659 660 idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb); 661 662 cb->args[0] = net_cb.idx; 663 return skb->len; 664 } 665 666 static void rtnl_net_notifyid(struct net *net, int cmd, int id) 667 { 668 struct sk_buff *msg; 669 int err = -ENOMEM; 670 671 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 672 if (!msg) 673 goto out; 674 675 err = rtnl_net_fill(msg, 0, 0, 0, cmd, net, id); 676 if (err < 0) 677 goto err_out; 678 679 rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0); 680 return; 681 682 err_out: 683 nlmsg_free(msg); 684 out: 685 rtnl_set_sk_err(net, RTNLGRP_NSID, err); 686 } 687 688 static int __init net_ns_init(void) 689 { 690 struct net_generic *ng; 691 692 #ifdef CONFIG_NET_NS 693 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), 694 SMP_CACHE_BYTES, 695 SLAB_PANIC, NULL); 696 697 /* Create workqueue for cleanup */ 698 netns_wq = create_singlethread_workqueue("netns"); 699 if (!netns_wq) 700 panic("Could not create netns workq"); 701 #endif 702 703 ng = net_alloc_generic(); 704 if (!ng) 705 panic("Could not allocate generic netns"); 706 707 rcu_assign_pointer(init_net.gen, ng); 708 709 mutex_lock(&net_mutex); 710 if (setup_net(&init_net, &init_user_ns)) 711 panic("Could not setup the initial network namespace"); 712 713 rtnl_lock(); 714 list_add_tail_rcu(&init_net.list, &net_namespace_list); 715 rtnl_unlock(); 716 717 mutex_unlock(&net_mutex); 718 719 register_pernet_subsys(&net_ns_ops); 720 721 rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, NULL); 722 rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid, 723 NULL); 724 725 return 0; 726 } 727 728 pure_initcall(net_ns_init); 729 730 #ifdef CONFIG_NET_NS 731 static int __register_pernet_operations(struct list_head *list, 732 struct pernet_operations *ops) 733 { 734 struct net *net; 735 int error; 736 LIST_HEAD(net_exit_list); 737 738 list_add_tail(&ops->list, list); 739 if (ops->init || (ops->id && ops->size)) { 740 for_each_net(net) { 741 error = ops_init(ops, net); 742 if (error) 743 goto out_undo; 744 list_add_tail(&net->exit_list, &net_exit_list); 745 } 746 } 747 return 0; 748 749 out_undo: 750 /* If I have an error cleanup all namespaces I initialized */ 751 list_del(&ops->list); 752 ops_exit_list(ops, &net_exit_list); 753 ops_free_list(ops, &net_exit_list); 754 return error; 755 } 756 757 static void __unregister_pernet_operations(struct pernet_operations *ops) 758 { 759 struct net *net; 760 LIST_HEAD(net_exit_list); 761 762 list_del(&ops->list); 763 for_each_net(net) 764 list_add_tail(&net->exit_list, &net_exit_list); 765 ops_exit_list(ops, &net_exit_list); 766 ops_free_list(ops, &net_exit_list); 767 } 768 769 #else 770 771 static int __register_pernet_operations(struct list_head *list, 772 struct pernet_operations *ops) 773 { 774 return ops_init(ops, &init_net); 775 } 776 777 static void __unregister_pernet_operations(struct pernet_operations *ops) 778 { 779 LIST_HEAD(net_exit_list); 780 list_add(&init_net.exit_list, &net_exit_list); 781 ops_exit_list(ops, &net_exit_list); 782 ops_free_list(ops, &net_exit_list); 783 } 784 785 #endif /* CONFIG_NET_NS */ 786 787 static DEFINE_IDA(net_generic_ids); 788 789 static int register_pernet_operations(struct list_head *list, 790 struct pernet_operations *ops) 791 { 792 int error; 793 794 if (ops->id) { 795 again: 796 error = ida_get_new_above(&net_generic_ids, 1, ops->id); 797 if (error < 0) { 798 if (error == -EAGAIN) { 799 ida_pre_get(&net_generic_ids, GFP_KERNEL); 800 goto again; 801 } 802 return error; 803 } 804 max_gen_ptrs = max_t(unsigned int, max_gen_ptrs, *ops->id); 805 } 806 error = __register_pernet_operations(list, ops); 807 if (error) { 808 rcu_barrier(); 809 if (ops->id) 810 ida_remove(&net_generic_ids, *ops->id); 811 } 812 813 return error; 814 } 815 816 static void unregister_pernet_operations(struct pernet_operations *ops) 817 { 818 819 __unregister_pernet_operations(ops); 820 rcu_barrier(); 821 if (ops->id) 822 ida_remove(&net_generic_ids, *ops->id); 823 } 824 825 /** 826 * register_pernet_subsys - register a network namespace subsystem 827 * @ops: pernet operations structure for the subsystem 828 * 829 * Register a subsystem which has init and exit functions 830 * that are called when network namespaces are created and 831 * destroyed respectively. 832 * 833 * When registered all network namespace init functions are 834 * called for every existing network namespace. Allowing kernel 835 * modules to have a race free view of the set of network namespaces. 836 * 837 * When a new network namespace is created all of the init 838 * methods are called in the order in which they were registered. 839 * 840 * When a network namespace is destroyed all of the exit methods 841 * are called in the reverse of the order with which they were 842 * registered. 843 */ 844 int register_pernet_subsys(struct pernet_operations *ops) 845 { 846 int error; 847 mutex_lock(&net_mutex); 848 error = register_pernet_operations(first_device, ops); 849 mutex_unlock(&net_mutex); 850 return error; 851 } 852 EXPORT_SYMBOL_GPL(register_pernet_subsys); 853 854 /** 855 * unregister_pernet_subsys - unregister a network namespace subsystem 856 * @ops: pernet operations structure to manipulate 857 * 858 * Remove the pernet operations structure from the list to be 859 * used when network namespaces are created or destroyed. In 860 * addition run the exit method for all existing network 861 * namespaces. 862 */ 863 void unregister_pernet_subsys(struct pernet_operations *ops) 864 { 865 mutex_lock(&net_mutex); 866 unregister_pernet_operations(ops); 867 mutex_unlock(&net_mutex); 868 } 869 EXPORT_SYMBOL_GPL(unregister_pernet_subsys); 870 871 /** 872 * register_pernet_device - register a network namespace device 873 * @ops: pernet operations structure for the subsystem 874 * 875 * Register a device which has init and exit functions 876 * that are called when network namespaces are created and 877 * destroyed respectively. 878 * 879 * When registered all network namespace init functions are 880 * called for every existing network namespace. Allowing kernel 881 * modules to have a race free view of the set of network namespaces. 882 * 883 * When a new network namespace is created all of the init 884 * methods are called in the order in which they were registered. 885 * 886 * When a network namespace is destroyed all of the exit methods 887 * are called in the reverse of the order with which they were 888 * registered. 889 */ 890 int register_pernet_device(struct pernet_operations *ops) 891 { 892 int error; 893 mutex_lock(&net_mutex); 894 error = register_pernet_operations(&pernet_list, ops); 895 if (!error && (first_device == &pernet_list)) 896 first_device = &ops->list; 897 mutex_unlock(&net_mutex); 898 return error; 899 } 900 EXPORT_SYMBOL_GPL(register_pernet_device); 901 902 /** 903 * unregister_pernet_device - unregister a network namespace netdevice 904 * @ops: pernet operations structure to manipulate 905 * 906 * Remove the pernet operations structure from the list to be 907 * used when network namespaces are created or destroyed. In 908 * addition run the exit method for all existing network 909 * namespaces. 910 */ 911 void unregister_pernet_device(struct pernet_operations *ops) 912 { 913 mutex_lock(&net_mutex); 914 if (&ops->list == first_device) 915 first_device = first_device->next; 916 unregister_pernet_operations(ops); 917 mutex_unlock(&net_mutex); 918 } 919 EXPORT_SYMBOL_GPL(unregister_pernet_device); 920 921 #ifdef CONFIG_NET_NS 922 static struct ns_common *netns_get(struct task_struct *task) 923 { 924 struct net *net = NULL; 925 struct nsproxy *nsproxy; 926 927 task_lock(task); 928 nsproxy = task->nsproxy; 929 if (nsproxy) 930 net = get_net(nsproxy->net_ns); 931 task_unlock(task); 932 933 return net ? &net->ns : NULL; 934 } 935 936 static inline struct net *to_net_ns(struct ns_common *ns) 937 { 938 return container_of(ns, struct net, ns); 939 } 940 941 static void netns_put(struct ns_common *ns) 942 { 943 put_net(to_net_ns(ns)); 944 } 945 946 static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns) 947 { 948 struct net *net = to_net_ns(ns); 949 950 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) || 951 !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) 952 return -EPERM; 953 954 put_net(nsproxy->net_ns); 955 nsproxy->net_ns = get_net(net); 956 return 0; 957 } 958 959 const struct proc_ns_operations netns_operations = { 960 .name = "net", 961 .type = CLONE_NEWNET, 962 .get = netns_get, 963 .put = netns_put, 964 .install = netns_install, 965 }; 966 #endif 967