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l2tp_core.c
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linux-6.19.14/net/l2tp/l2tp_core.c
1// SPDX-License-Identifier: GPL-2.0-only 2/* L2TP core. 3 * 4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd 5 * 6 * This file contains some code of the original L2TPv2 pppol2tp 7 * driver, which has the following copyright: 8 * 9 * Authors: Martijn van Oosterhout <kleptog@svana.org> 10 * James Chapman (jchapman@katalix.com) 11 * Contributors: 12 * Michal Ostrowski <mostrows@speakeasy.net> 13 * Arnaldo Carvalho de Melo <acme@xconectiva.com.br> 14 * David S. Miller (davem@redhat.com) 15 */ 16 17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 19#include <linux/module.h> 20#include <linux/string.h> 21#include <linux/list.h> 22#include <linux/rculist.h> 23#include <linux/uaccess.h> 24 25#include <linux/kernel.h> 26#include <linux/spinlock.h> 27#include <linux/kthread.h> 28#include <linux/sched.h> 29#include <linux/slab.h> 30#include <linux/errno.h> 31#include <linux/jiffies.h> 32 33#include <linux/netdevice.h> 34#include <linux/net.h> 35#include <linux/inetdevice.h> 36#include <linux/skbuff.h> 37#include <linux/init.h> 38#include <linux/in.h> 39#include <linux/ip.h> 40#include <linux/udp.h> 41#include <linux/l2tp.h> 42#include <linux/sort.h> 43#include <linux/file.h> 44#include <linux/nsproxy.h> 45#include <net/net_namespace.h> 46#include <net/netns/generic.h> 47#include <net/dst.h> 48#include <net/ip.h> 49#include <net/udp.h> 50#include <net/udp_tunnel.h> 51#include <net/inet_common.h> 52#include <net/xfrm.h> 53#include <net/protocol.h> 54#include <net/inet6_connection_sock.h> 55#include <net/inet_ecn.h> 56#include <net/ip6_route.h> 57#include <net/ip6_checksum.h> 58 59#include <asm/byteorder.h> 60#include <linux/atomic.h> 61 62#include "l2tp_core.h" 63 64#define CREATE_TRACE_POINTS 65#include "trace.h" 66 67#define L2TP_DRV_VERSION "V2.0" 68 69/* L2TP header constants */ 70#define L2TP_HDRFLAG_T 0x8000 71#define L2TP_HDRFLAG_L 0x4000 72#define L2TP_HDRFLAG_S 0x0800 73#define L2TP_HDRFLAG_O 0x0200 74#define L2TP_HDRFLAG_P 0x0100 75 76#define L2TP_HDR_VER_MASK 0x000F 77#define L2TP_HDR_VER_2 0x0002 78#define L2TP_HDR_VER_3 0x0003 79 80/* L2TPv3 default L2-specific sublayer */ 81#define L2TP_SLFLAG_S 0x40000000 82#define L2TP_SL_SEQ_MASK 0x00ffffff 83 84#define L2TP_HDR_SIZE_MAX 14 85 86/* Default trace flags */ 87#define L2TP_DEFAULT_DEBUG_FLAGS 0 88 89#define L2TP_DEPTH_NESTING 2 90#if L2TP_DEPTH_NESTING == SINGLE_DEPTH_NESTING 91#error "L2TP requires its own lockdep subclass" 92#endif 93 94/* Private data stored for received packets in the skb. 95 */ 96struct l2tp_skb_cb { 97 u32 ns; 98 u16 has_seq; 99 u16 length; 100 unsigned long expires; 101}; 102 103#define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *)&(skb)->cb[sizeof(struct inet_skb_parm)]) 104 105static struct workqueue_struct *l2tp_wq; 106 107/* per-net private data for this module */ 108static unsigned int l2tp_net_id; 109struct l2tp_net { 110 /* Lock for write access to l2tp_tunnel_idr */ 111 spinlock_t l2tp_tunnel_idr_lock; 112 struct idr l2tp_tunnel_idr; 113 /* Lock for write access to l2tp_v[23]_session_idr/htable */ 114 spinlock_t l2tp_session_idr_lock; 115 struct idr l2tp_v2_session_idr; 116 struct idr l2tp_v3_session_idr; 117 struct hlist_head l2tp_v3_session_htable[16]; 118}; 119 120static u32 l2tp_v2_session_key(u16 tunnel_id, u16 session_id) 121{ 122 return ((u32)tunnel_id) << 16 | session_id; 123} 124 125static unsigned long l2tp_v3_session_hashkey(struct sock *sk, u32 session_id) 126{ 127 return ((unsigned long)sk) + session_id; 128} 129 130#if IS_ENABLED(CONFIG_IPV6) 131static bool l2tp_sk_is_v6(struct sock *sk) 132{ 133 return sk->sk_family == PF_INET6 && 134 !ipv6_addr_v4mapped(&sk->sk_v6_daddr); 135} 136#endif 137 138static struct l2tp_net *l2tp_pernet(const struct net *net) 139{ 140 return net_generic(net, l2tp_net_id); 141} 142 143static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) 144{ 145 struct sock *sk = tunnel->sock; 146 147 trace_free_tunnel(tunnel); 148 149 if (sk) { 150 /* Disable udp encapsulation */ 151 switch (tunnel->encap) { 152 case L2TP_ENCAPTYPE_UDP: 153 /* No longer an encapsulation socket. See net/ipv4/udp.c */ 154 WRITE_ONCE(udp_sk(sk)->encap_type, 0); 155 udp_sk(sk)->encap_rcv = NULL; 156 udp_sk(sk)->encap_destroy = NULL; 157 break; 158 case L2TP_ENCAPTYPE_IP: 159 break; 160 } 161 162 tunnel->sock = NULL; 163 sock_put(sk); 164 } 165 166 kfree_rcu(tunnel, rcu); 167} 168 169static void l2tp_session_free(struct l2tp_session *session) 170{ 171 trace_free_session(session); 172 if (session->tunnel) 173 l2tp_tunnel_put(session->tunnel); 174 kfree_rcu(session, rcu); 175} 176 177struct l2tp_tunnel *l2tp_sk_to_tunnel(const struct sock *sk) 178{ 179 const struct net *net = sock_net(sk); 180 unsigned long tunnel_id, tmp; 181 struct l2tp_tunnel *tunnel; 182 struct l2tp_net *pn; 183 184 rcu_read_lock_bh(); 185 pn = l2tp_pernet(net); 186 idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) { 187 if (tunnel && 188 tunnel->sock == sk && 189 refcount_inc_not_zero(&tunnel->ref_count)) { 190 rcu_read_unlock_bh(); 191 return tunnel; 192 } 193 } 194 rcu_read_unlock_bh(); 195 196 return NULL; 197} 198EXPORT_SYMBOL_GPL(l2tp_sk_to_tunnel); 199 200void l2tp_tunnel_put(struct l2tp_tunnel *tunnel) 201{ 202 if (refcount_dec_and_test(&tunnel->ref_count)) 203 l2tp_tunnel_free(tunnel); 204} 205EXPORT_SYMBOL_GPL(l2tp_tunnel_put); 206 207void l2tp_session_put(struct l2tp_session *session) 208{ 209 if (refcount_dec_and_test(&session->ref_count)) 210 l2tp_session_free(session); 211} 212EXPORT_SYMBOL_GPL(l2tp_session_put); 213 214/* Lookup a tunnel. A new reference is held on the returned tunnel. */ 215struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id) 216{ 217 const struct l2tp_net *pn = l2tp_pernet(net); 218 struct l2tp_tunnel *tunnel; 219 220 rcu_read_lock_bh(); 221 tunnel = idr_find(&pn->l2tp_tunnel_idr, tunnel_id); 222 if (tunnel && refcount_inc_not_zero(&tunnel->ref_count)) { 223 rcu_read_unlock_bh(); 224 return tunnel; 225 } 226 rcu_read_unlock_bh(); 227 228 return NULL; 229} 230EXPORT_SYMBOL_GPL(l2tp_tunnel_get); 231 232struct l2tp_tunnel *l2tp_tunnel_get_next(const struct net *net, unsigned long *key) 233{ 234 struct l2tp_net *pn = l2tp_pernet(net); 235 struct l2tp_tunnel *tunnel = NULL; 236 237 rcu_read_lock_bh(); 238again: 239 tunnel = idr_get_next_ul(&pn->l2tp_tunnel_idr, key); 240 if (tunnel) { 241 if (refcount_inc_not_zero(&tunnel->ref_count)) { 242 rcu_read_unlock_bh(); 243 return tunnel; 244 } 245 (*key)++; 246 goto again; 247 } 248 rcu_read_unlock_bh(); 249 250 return NULL; 251} 252EXPORT_SYMBOL_GPL(l2tp_tunnel_get_next); 253 254struct l2tp_session *l2tp_v3_session_get(const struct net *net, struct sock *sk, u32 session_id) 255{ 256 const struct l2tp_net *pn = l2tp_pernet(net); 257 struct l2tp_session *session; 258 259 rcu_read_lock_bh(); 260 session = idr_find(&pn->l2tp_v3_session_idr, session_id); 261 if (session && !hash_hashed(&session->hlist) && 262 refcount_inc_not_zero(&session->ref_count)) { 263 rcu_read_unlock_bh(); 264 return session; 265 } 266 267 /* If we get here and session is non-NULL, the session_id 268 * collides with one in another tunnel. If sk is non-NULL, 269 * find the session matching sk. 270 */ 271 if (session && sk) { 272 unsigned long key = l2tp_v3_session_hashkey(sk, session->session_id); 273 274 hash_for_each_possible_rcu(pn->l2tp_v3_session_htable, session, 275 hlist, key) { 276 /* session->tunnel may be NULL if another thread is in 277 * l2tp_session_register and has added an item to 278 * l2tp_v3_session_htable but hasn't yet added the 279 * session to its tunnel's session_list. 280 */ 281 struct l2tp_tunnel *tunnel = READ_ONCE(session->tunnel); 282 283 if (session->session_id == session_id && 284 tunnel && tunnel->sock == sk && 285 refcount_inc_not_zero(&session->ref_count)) { 286 rcu_read_unlock_bh(); 287 return session; 288 } 289 } 290 } 291 rcu_read_unlock_bh(); 292 293 return NULL; 294} 295EXPORT_SYMBOL_GPL(l2tp_v3_session_get); 296 297struct l2tp_session *l2tp_v2_session_get(const struct net *net, u16 tunnel_id, u16 session_id) 298{ 299 u32 session_key = l2tp_v2_session_key(tunnel_id, session_id); 300 const struct l2tp_net *pn = l2tp_pernet(net); 301 struct l2tp_session *session; 302 303 rcu_read_lock_bh(); 304 session = idr_find(&pn->l2tp_v2_session_idr, session_key); 305 if (session && refcount_inc_not_zero(&session->ref_count)) { 306 rcu_read_unlock_bh(); 307 return session; 308 } 309 rcu_read_unlock_bh(); 310 311 return NULL; 312} 313EXPORT_SYMBOL_GPL(l2tp_v2_session_get); 314 315struct l2tp_session *l2tp_session_get(const struct net *net, struct sock *sk, int pver, 316 u32 tunnel_id, u32 session_id) 317{ 318 if (pver == L2TP_HDR_VER_2) 319 return l2tp_v2_session_get(net, tunnel_id, session_id); 320 else 321 return l2tp_v3_session_get(net, sk, session_id); 322} 323EXPORT_SYMBOL_GPL(l2tp_session_get); 324 325static struct l2tp_session *l2tp_v2_session_get_next(const struct net *net, 326 u16 tid, 327 unsigned long *key) 328{ 329 struct l2tp_net *pn = l2tp_pernet(net); 330 struct l2tp_session *session = NULL; 331 332 /* Start searching within the range of the tid */ 333 if (*key == 0) 334 *key = l2tp_v2_session_key(tid, 0); 335 336 rcu_read_lock_bh(); 337again: 338 session = idr_get_next_ul(&pn->l2tp_v2_session_idr, key); 339 if (session) { 340 struct l2tp_tunnel *tunnel = READ_ONCE(session->tunnel); 341 342 /* ignore sessions with id 0 as they are internal for pppol2tp */ 343 if (session->session_id == 0) { 344 (*key)++; 345 goto again; 346 } 347 348 if (tunnel->tunnel_id == tid && 349 refcount_inc_not_zero(&session->ref_count)) { 350 rcu_read_unlock_bh(); 351 return session; 352 } 353 354 (*key)++; 355 if (tunnel->tunnel_id == tid) 356 goto again; 357 } 358 rcu_read_unlock_bh(); 359 360 return NULL; 361} 362 363static struct l2tp_session *l2tp_v3_session_get_next(const struct net *net, 364 u32 tid, struct sock *sk, 365 unsigned long *key) 366{ 367 struct l2tp_net *pn = l2tp_pernet(net); 368 struct l2tp_session *session = NULL; 369 370 rcu_read_lock_bh(); 371again: 372 session = idr_get_next_ul(&pn->l2tp_v3_session_idr, key); 373 if (session && !hash_hashed(&session->hlist)) { 374 struct l2tp_tunnel *tunnel = READ_ONCE(session->tunnel); 375 376 if (tunnel && tunnel->tunnel_id == tid && 377 refcount_inc_not_zero(&session->ref_count)) { 378 rcu_read_unlock_bh(); 379 return session; 380 } 381 382 (*key)++; 383 goto again; 384 } 385 386 /* If we get here and session is non-NULL, the IDR entry may be one 387 * where the session_id collides with one in another tunnel. Check 388 * session_htable for a match. There can only be one session of a given 389 * ID per tunnel so we can return as soon as a match is found. 390 */ 391 if (session && hash_hashed(&session->hlist)) { 392 unsigned long hkey = l2tp_v3_session_hashkey(sk, session->session_id); 393 u32 sid = session->session_id; 394 395 hash_for_each_possible_rcu(pn->l2tp_v3_session_htable, session, 396 hlist, hkey) { 397 struct l2tp_tunnel *tunnel = READ_ONCE(session->tunnel); 398 399 if (session->session_id == sid && 400 tunnel && tunnel->tunnel_id == tid && 401 refcount_inc_not_zero(&session->ref_count)) { 402 rcu_read_unlock_bh(); 403 return session; 404 } 405 } 406 407 /* If no match found, the colliding session ID isn't in our 408 * tunnel so try the next session ID. 409 */ 410 (*key)++; 411 goto again; 412 } 413 414 rcu_read_unlock_bh(); 415 416 return NULL; 417} 418 419struct l2tp_session *l2tp_session_get_next(const struct net *net, struct sock *sk, int pver, 420 u32 tunnel_id, unsigned long *key) 421{ 422 if (pver == L2TP_HDR_VER_2) 423 return l2tp_v2_session_get_next(net, tunnel_id, key); 424 else 425 return l2tp_v3_session_get_next(net, tunnel_id, sk, key); 426} 427EXPORT_SYMBOL_GPL(l2tp_session_get_next); 428 429/* Lookup a session by interface name. 430 * This is very inefficient but is only used by management interfaces. 431 */ 432struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, 433 const char *ifname) 434{ 435 struct l2tp_net *pn = l2tp_pernet(net); 436 unsigned long tunnel_id, tmp; 437 struct l2tp_session *session; 438 struct l2tp_tunnel *tunnel; 439 440 rcu_read_lock_bh(); 441 idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) { 442 if (tunnel) { 443 list_for_each_entry_rcu(session, &tunnel->session_list, list) { 444 if (!strcmp(session->ifname, ifname)) { 445 refcount_inc(&session->ref_count); 446 rcu_read_unlock_bh(); 447 448 return session; 449 } 450 } 451 } 452 } 453 rcu_read_unlock_bh(); 454 455 return NULL; 456} 457EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname); 458 459static void l2tp_session_coll_list_add(struct l2tp_session_coll_list *clist, 460 struct l2tp_session *session) 461{ 462 refcount_inc(&session->ref_count); 463 WARN_ON_ONCE(session->coll_list); 464 session->coll_list = clist; 465 spin_lock(&clist->lock); 466 list_add(&session->clist, &clist->list); 467 spin_unlock(&clist->lock); 468} 469 470static int l2tp_session_collision_add(struct l2tp_net *pn, 471 struct l2tp_session *session1, 472 struct l2tp_session *session2) 473{ 474 struct l2tp_session_coll_list *clist; 475 476 lockdep_assert_held(&pn->l2tp_session_idr_lock); 477 478 if (!session2) 479 return -EEXIST; 480 481 /* If existing session is in IP-encap tunnel, refuse new session */ 482 if (session2->tunnel->encap == L2TP_ENCAPTYPE_IP) 483 return -EEXIST; 484 485 clist = session2->coll_list; 486 if (!clist) { 487 /* First collision. Allocate list to manage the collided sessions 488 * and add the existing session to the list. 489 */ 490 clist = kmalloc(sizeof(*clist), GFP_ATOMIC); 491 if (!clist) 492 return -ENOMEM; 493 494 spin_lock_init(&clist->lock); 495 INIT_LIST_HEAD(&clist->list); 496 refcount_set(&clist->ref_count, 1); 497 l2tp_session_coll_list_add(clist, session2); 498 } 499 500 /* If existing session isn't already in the session hlist, add it. */ 501 if (!hash_hashed(&session2->hlist)) 502 hash_add_rcu(pn->l2tp_v3_session_htable, &session2->hlist, 503 session2->hlist_key); 504 505 /* Add new session to the hlist and collision list */ 506 hash_add_rcu(pn->l2tp_v3_session_htable, &session1->hlist, 507 session1->hlist_key); 508 refcount_inc(&clist->ref_count); 509 l2tp_session_coll_list_add(clist, session1); 510 511 return 0; 512} 513 514static void l2tp_session_collision_del(struct l2tp_net *pn, 515 struct l2tp_session *session) 516{ 517 struct l2tp_session_coll_list *clist = session->coll_list; 518 unsigned long session_key = session->session_id; 519 struct l2tp_session *session2; 520 521 lockdep_assert_held(&pn->l2tp_session_idr_lock); 522 523 hash_del_rcu(&session->hlist); 524 525 if (clist) { 526 /* Remove session from its collision list. If there 527 * are other sessions with the same ID, replace this 528 * session's IDR entry with that session, otherwise 529 * remove the IDR entry. If this is the last session, 530 * the collision list data is freed. 531 */ 532 spin_lock(&clist->lock); 533 list_del_init(&session->clist); 534 session2 = list_first_entry_or_null(&clist->list, struct l2tp_session, clist); 535 if (session2) { 536 void *old = idr_replace(&pn->l2tp_v3_session_idr, session2, session_key); 537 538 WARN_ON_ONCE(IS_ERR_VALUE(old)); 539 } else { 540 void *removed = idr_remove(&pn->l2tp_v3_session_idr, session_key); 541 542 WARN_ON_ONCE(removed != session); 543 } 544 session->coll_list = NULL; 545 spin_unlock(&clist->lock); 546 if (refcount_dec_and_test(&clist->ref_count)) 547 kfree(clist); 548 l2tp_session_put(session); 549 } 550} 551 552int l2tp_session_register(struct l2tp_session *session, 553 struct l2tp_tunnel *tunnel) 554{ 555 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 556 struct l2tp_session *other_session = NULL; 557 void *old = NULL; 558 u32 session_key; 559 int err; 560 561 spin_lock_bh(&tunnel->list_lock); 562 spin_lock_bh(&pn->l2tp_session_idr_lock); 563 564 if (!tunnel->acpt_newsess) { 565 err = -ENODEV; 566 goto out; 567 } 568 569 if (tunnel->version == L2TP_HDR_VER_3) { 570 session_key = session->session_id; 571 err = idr_alloc_u32(&pn->l2tp_v3_session_idr, NULL, 572 &session_key, session_key, GFP_ATOMIC); 573 /* IP encap expects session IDs to be globally unique, while 574 * UDP encap doesn't. This isn't per the RFC, which says that 575 * sessions are identified only by the session ID, but is to 576 * support existing userspace which depends on it. 577 */ 578 if (err == -ENOSPC && tunnel->encap == L2TP_ENCAPTYPE_UDP) { 579 other_session = idr_find(&pn->l2tp_v3_session_idr, 580 session_key); 581 err = l2tp_session_collision_add(pn, session, 582 other_session); 583 } 584 } else { 585 session_key = l2tp_v2_session_key(tunnel->tunnel_id, 586 session->session_id); 587 err = idr_alloc_u32(&pn->l2tp_v2_session_idr, NULL, 588 &session_key, session_key, GFP_ATOMIC); 589 } 590 591 if (err) { 592 if (err == -ENOSPC) 593 err = -EEXIST; 594 goto out; 595 } 596 597 refcount_inc(&tunnel->ref_count); 598 WRITE_ONCE(session->tunnel, tunnel); 599 list_add_rcu(&session->list, &tunnel->session_list); 600 601 /* this makes session available to lockless getters */ 602 if (tunnel->version == L2TP_HDR_VER_3) { 603 if (!other_session) 604 old = idr_replace(&pn->l2tp_v3_session_idr, session, session_key); 605 } else { 606 old = idr_replace(&pn->l2tp_v2_session_idr, session, session_key); 607 } 608 609 /* old should be NULL, unless something removed or modified 610 * the IDR entry after our idr_alloc_32 above (which shouldn't 611 * happen). 612 */ 613 WARN_ON_ONCE(old); 614out: 615 spin_unlock_bh(&pn->l2tp_session_idr_lock); 616 spin_unlock_bh(&tunnel->list_lock); 617 618 if (!err) 619 trace_register_session(session); 620 621 return err; 622} 623EXPORT_SYMBOL_GPL(l2tp_session_register); 624 625/***************************************************************************** 626 * Receive data handling 627 *****************************************************************************/ 628 629/* Queue a skb in order. We come here only if the skb has an L2TP sequence 630 * number. 631 */ 632static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) 633{ 634 struct sk_buff *skbp; 635 struct sk_buff *tmp; 636 u32 ns = L2TP_SKB_CB(skb)->ns; 637 638 spin_lock_bh(&session->reorder_q.lock); 639 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { 640 if (L2TP_SKB_CB(skbp)->ns > ns) { 641 __skb_queue_before(&session->reorder_q, skbp, skb); 642 atomic_long_inc(&session->stats.rx_oos_packets); 643 goto out; 644 } 645 } 646 647 __skb_queue_tail(&session->reorder_q, skb); 648 649out: 650 spin_unlock_bh(&session->reorder_q.lock); 651} 652 653/* Dequeue a single skb. 654 */ 655static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) 656{ 657 struct l2tp_tunnel *tunnel = session->tunnel; 658 int length = L2TP_SKB_CB(skb)->length; 659 660 /* We're about to requeue the skb, so return resources 661 * to its current owner (a socket receive buffer). 662 */ 663 skb_orphan(skb); 664 665 atomic_long_inc(&tunnel->stats.rx_packets); 666 atomic_long_add(length, &tunnel->stats.rx_bytes); 667 atomic_long_inc(&session->stats.rx_packets); 668 atomic_long_add(length, &session->stats.rx_bytes); 669 670 if (L2TP_SKB_CB(skb)->has_seq) { 671 /* Bump our Nr */ 672 session->nr++; 673 session->nr &= session->nr_max; 674 trace_session_seqnum_update(session); 675 } 676 677 /* call private receive handler */ 678 if (session->recv_skb) 679 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); 680 else 681 kfree_skb(skb); 682} 683 684/* Dequeue skbs from the session's reorder_q, subject to packet order. 685 * Skbs that have been in the queue for too long are simply discarded. 686 */ 687static void l2tp_recv_dequeue(struct l2tp_session *session) 688{ 689 struct sk_buff *skb; 690 struct sk_buff *tmp; 691 692 /* If the pkt at the head of the queue has the nr that we 693 * expect to send up next, dequeue it and any other 694 * in-sequence packets behind it. 695 */ 696start: 697 spin_lock_bh(&session->reorder_q.lock); 698 skb_queue_walk_safe(&session->reorder_q, skb, tmp) { 699 struct l2tp_skb_cb *cb = L2TP_SKB_CB(skb); 700 701 /* If the packet has been pending on the queue for too long, discard it */ 702 if (time_after(jiffies, cb->expires)) { 703 atomic_long_inc(&session->stats.rx_seq_discards); 704 atomic_long_inc(&session->stats.rx_errors); 705 trace_session_pkt_expired(session, cb->ns); 706 session->reorder_skip = 1; 707 __skb_unlink(skb, &session->reorder_q); 708 kfree_skb(skb); 709 continue; 710 } 711 712 if (cb->has_seq) { 713 if (session->reorder_skip) { 714 session->reorder_skip = 0; 715 session->nr = cb->ns; 716 trace_session_seqnum_reset(session); 717 } 718 if (cb->ns != session->nr) 719 goto out; 720 } 721 __skb_unlink(skb, &session->reorder_q); 722 723 /* Process the skb. We release the queue lock while we 724 * do so to let other contexts process the queue. 725 */ 726 spin_unlock_bh(&session->reorder_q.lock); 727 l2tp_recv_dequeue_skb(session, skb); 728 goto start; 729 } 730 731out: 732 spin_unlock_bh(&session->reorder_q.lock); 733} 734 735static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr) 736{ 737 u32 nws; 738 739 if (nr >= session->nr) 740 nws = nr - session->nr; 741 else 742 nws = (session->nr_max + 1) - (session->nr - nr); 743 744 return nws < session->nr_window_size; 745} 746 747/* If packet has sequence numbers, queue it if acceptable. Returns 0 if 748 * acceptable, else non-zero. 749 */ 750static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb) 751{ 752 struct l2tp_skb_cb *cb = L2TP_SKB_CB(skb); 753 754 if (!l2tp_seq_check_rx_window(session, cb->ns)) { 755 /* Packet sequence number is outside allowed window. 756 * Discard it. 757 */ 758 trace_session_pkt_outside_rx_window(session, cb->ns); 759 goto discard; 760 } 761 762 if (session->reorder_timeout != 0) { 763 /* Packet reordering enabled. Add skb to session's 764 * reorder queue, in order of ns. 765 */ 766 l2tp_recv_queue_skb(session, skb); 767 goto out; 768 } 769 770 /* Packet reordering disabled. Discard out-of-sequence packets, while 771 * tracking the number if in-sequence packets after the first OOS packet 772 * is seen. After nr_oos_count_max in-sequence packets, reset the 773 * sequence number to re-enable packet reception. 774 */ 775 if (cb->ns == session->nr) { 776 skb_queue_tail(&session->reorder_q, skb); 777 } else { 778 u32 nr_oos = cb->ns; 779 u32 nr_next = (session->nr_oos + 1) & session->nr_max; 780 781 if (nr_oos == nr_next) 782 session->nr_oos_count++; 783 else 784 session->nr_oos_count = 0; 785 786 session->nr_oos = nr_oos; 787 if (session->nr_oos_count > session->nr_oos_count_max) { 788 session->reorder_skip = 1; 789 } 790 if (!session->reorder_skip) { 791 atomic_long_inc(&session->stats.rx_seq_discards); 792 trace_session_pkt_oos(session, cb->ns); 793 goto discard; 794 } 795 skb_queue_tail(&session->reorder_q, skb); 796 } 797 798out: 799 return 0; 800 801discard: 802 return 1; 803} 804 805/* Do receive processing of L2TP data frames. We handle both L2TPv2 806 * and L2TPv3 data frames here. 807 * 808 * L2TPv2 Data Message Header 809 * 810 * 0 1 2 3 811 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 812 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 813 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | 814 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 815 * | Tunnel ID | Session ID | 816 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 817 * | Ns (opt) | Nr (opt) | 818 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 819 * | Offset Size (opt) | Offset pad... (opt) 820 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 821 * 822 * Data frames are marked by T=0. All other fields are the same as 823 * those in L2TP control frames. 824 * 825 * L2TPv3 Data Message Header 826 * 827 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 828 * | L2TP Session Header | 829 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 830 * | L2-Specific Sublayer | 831 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 832 * | Tunnel Payload ... 833 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 834 * 835 * L2TPv3 Session Header Over IP 836 * 837 * 0 1 2 3 838 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 839 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 840 * | Session ID | 841 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 842 * | Cookie (optional, maximum 64 bits)... 843 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 844 * | 845 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 846 * 847 * L2TPv3 L2-Specific Sublayer Format 848 * 849 * 0 1 2 3 850 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 851 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 852 * |x|S|x|x|x|x|x|x| Sequence Number | 853 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 854 * 855 * Cookie value and sublayer format are negotiated with the peer when 856 * the session is set up. Unlike L2TPv2, we do not need to parse the 857 * packet header to determine if optional fields are present. 858 * 859 * Caller must already have parsed the frame and determined that it is 860 * a data (not control) frame before coming here. Fields up to the 861 * session-id have already been parsed and ptr points to the data 862 * after the session-id. 863 */ 864void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 865 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 866 int length) 867{ 868 struct l2tp_tunnel *tunnel = session->tunnel; 869 int offset; 870 871 /* Parse and check optional cookie */ 872 if (session->peer_cookie_len > 0) { 873 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { 874 pr_debug_ratelimited("%s: cookie mismatch (%u/%u). Discarding.\n", 875 tunnel->name, tunnel->tunnel_id, 876 session->session_id); 877 atomic_long_inc(&session->stats.rx_cookie_discards); 878 goto discard; 879 } 880 ptr += session->peer_cookie_len; 881 } 882 883 /* Handle the optional sequence numbers. Sequence numbers are 884 * in different places for L2TPv2 and L2TPv3. 885 * 886 * If we are the LAC, enable/disable sequence numbers under 887 * the control of the LNS. If no sequence numbers present but 888 * we were expecting them, discard frame. 889 */ 890 L2TP_SKB_CB(skb)->has_seq = 0; 891 if (tunnel->version == L2TP_HDR_VER_2) { 892 if (hdrflags & L2TP_HDRFLAG_S) { 893 /* Store L2TP info in the skb */ 894 L2TP_SKB_CB(skb)->ns = ntohs(*(__be16 *)ptr); 895 L2TP_SKB_CB(skb)->has_seq = 1; 896 ptr += 2; 897 /* Skip past nr in the header */ 898 ptr += 2; 899 900 } 901 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 902 u32 l2h = ntohl(*(__be32 *)ptr); 903 904 if (l2h & 0x40000000) { 905 /* Store L2TP info in the skb */ 906 L2TP_SKB_CB(skb)->ns = l2h & 0x00ffffff; 907 L2TP_SKB_CB(skb)->has_seq = 1; 908 } 909 ptr += 4; 910 } 911 912 if (L2TP_SKB_CB(skb)->has_seq) { 913 /* Received a packet with sequence numbers. If we're the LAC, 914 * check if we sre sending sequence numbers and if not, 915 * configure it so. 916 */ 917 if (!session->lns_mode && !session->send_seq) { 918 trace_session_seqnum_lns_enable(session); 919 session->send_seq = 1; 920 l2tp_session_set_header_len(session, tunnel->version, 921 tunnel->encap); 922 } 923 } else { 924 /* No sequence numbers. 925 * If user has configured mandatory sequence numbers, discard. 926 */ 927 if (session->recv_seq) { 928 pr_debug_ratelimited("%s: recv data has no seq numbers when required. Discarding.\n", 929 session->name); 930 atomic_long_inc(&session->stats.rx_seq_discards); 931 goto discard; 932 } 933 934 /* If we're the LAC and we're sending sequence numbers, the 935 * LNS has requested that we no longer send sequence numbers. 936 * If we're the LNS and we're sending sequence numbers, the 937 * LAC is broken. Discard the frame. 938 */ 939 if (!session->lns_mode && session->send_seq) { 940 trace_session_seqnum_lns_disable(session); 941 session->send_seq = 0; 942 l2tp_session_set_header_len(session, tunnel->version, 943 tunnel->encap); 944 } else if (session->send_seq) { 945 pr_debug_ratelimited("%s: recv data has no seq numbers when required. Discarding.\n", 946 session->name); 947 atomic_long_inc(&session->stats.rx_seq_discards); 948 goto discard; 949 } 950 } 951 952 /* Session data offset is defined only for L2TPv2 and is 953 * indicated by an optional 16-bit value in the header. 954 */ 955 if (tunnel->version == L2TP_HDR_VER_2) { 956 /* If offset bit set, skip it. */ 957 if (hdrflags & L2TP_HDRFLAG_O) { 958 offset = ntohs(*(__be16 *)ptr); 959 ptr += 2 + offset; 960 } 961 } 962 963 offset = ptr - optr; 964 if (!pskb_may_pull(skb, offset)) 965 goto discard; 966 967 __skb_pull(skb, offset); 968 969 /* Prepare skb for adding to the session's reorder_q. Hold 970 * packets for max reorder_timeout or 1 second if not 971 * reordering. 972 */ 973 L2TP_SKB_CB(skb)->length = length; 974 L2TP_SKB_CB(skb)->expires = jiffies + 975 (session->reorder_timeout ? session->reorder_timeout : HZ); 976 977 /* Add packet to the session's receive queue. Reordering is done here, if 978 * enabled. Saved L2TP protocol info is stored in skb->sb[]. 979 */ 980 if (L2TP_SKB_CB(skb)->has_seq) { 981 if (l2tp_recv_data_seq(session, skb)) 982 goto discard; 983 } else { 984 /* No sequence numbers. Add the skb to the tail of the 985 * reorder queue. This ensures that it will be 986 * delivered after all previous sequenced skbs. 987 */ 988 skb_queue_tail(&session->reorder_q, skb); 989 } 990 991 /* Try to dequeue as many skbs from reorder_q as we can. */ 992 l2tp_recv_dequeue(session); 993 994 return; 995 996discard: 997 atomic_long_inc(&session->stats.rx_errors); 998 kfree_skb(skb); 999} 1000EXPORT_SYMBOL_GPL(l2tp_recv_common); 1001 1002/* Drop skbs from the session's reorder_q 1003 */ 1004static void l2tp_session_queue_purge(struct l2tp_session *session) 1005{ 1006 struct sk_buff *skb = NULL; 1007 1008 while ((skb = skb_dequeue(&session->reorder_q))) { 1009 atomic_long_inc(&session->stats.rx_errors); 1010 kfree_skb(skb); 1011 } 1012} 1013 1014/* UDP encapsulation receive handler. See net/ipv4/udp.c for details. */ 1015int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 1016{ 1017 struct l2tp_session *session = NULL; 1018 struct l2tp_tunnel *tunnel = NULL; 1019 struct net *net = sock_net(sk); 1020 unsigned char *ptr, *optr; 1021 u16 hdrflags; 1022 u16 version; 1023 int length; 1024 1025 /* UDP has verified checksum */ 1026 1027 /* UDP always verifies the packet length. */ 1028 __skb_pull(skb, sizeof(struct udphdr)); 1029 1030 /* Short packet? */ 1031 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_MAX)) 1032 goto pass; 1033 1034 /* Point to L2TP header */ 1035 optr = skb->data; 1036 ptr = skb->data; 1037 1038 /* Get L2TP header flags */ 1039 hdrflags = ntohs(*(__be16 *)ptr); 1040 1041 /* Get protocol version */ 1042 version = hdrflags & L2TP_HDR_VER_MASK; 1043 1044 /* Get length of L2TP packet */ 1045 length = skb->len; 1046 1047 /* If type is control packet, it is handled by userspace. */ 1048 if (hdrflags & L2TP_HDRFLAG_T) 1049 goto pass; 1050 1051 /* Skip flags */ 1052 ptr += 2; 1053 1054 if (version == L2TP_HDR_VER_2) { 1055 u16 tunnel_id, session_id; 1056 1057 /* If length is present, skip it */ 1058 if (hdrflags & L2TP_HDRFLAG_L) 1059 ptr += 2; 1060 1061 /* Extract tunnel and session ID */ 1062 tunnel_id = ntohs(*(__be16 *)ptr); 1063 ptr += 2; 1064 session_id = ntohs(*(__be16 *)ptr); 1065 ptr += 2; 1066 1067 session = l2tp_v2_session_get(net, tunnel_id, session_id); 1068 } else { 1069 u32 session_id; 1070 1071 ptr += 2; /* skip reserved bits */ 1072 session_id = ntohl(*(__be32 *)ptr); 1073 ptr += 4; 1074 1075 session = l2tp_v3_session_get(net, sk, session_id); 1076 } 1077 1078 if (!session || !session->recv_skb) { 1079 if (session) 1080 l2tp_session_put(session); 1081 1082 /* Not found? Pass to userspace to deal with */ 1083 goto pass; 1084 } 1085 1086 tunnel = session->tunnel; 1087 1088 /* Check protocol version */ 1089 if (version != tunnel->version) { 1090 l2tp_session_put(session); 1091 goto invalid; 1092 } 1093 1094 if (version == L2TP_HDR_VER_3 && 1095 l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) { 1096 l2tp_session_put(session); 1097 goto invalid; 1098 } 1099 1100 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length); 1101 l2tp_session_put(session); 1102 1103 return 0; 1104 1105invalid: 1106 atomic_long_inc(&tunnel->stats.rx_invalid); 1107 1108pass: 1109 /* Put UDP header back */ 1110 __skb_push(skb, sizeof(struct udphdr)); 1111 1112 return 1; 1113} 1114EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); 1115 1116/* UDP encapsulation receive error handler. See net/ipv4/udp.c for details. */ 1117static void l2tp_udp_encap_err_recv(struct sock *sk, struct sk_buff *skb, int err, 1118 __be16 port, u32 info, u8 *payload) 1119{ 1120 sk->sk_err = err; 1121 sk_error_report(sk); 1122 1123 if (ip_hdr(skb)->version == IPVERSION) { 1124 if (inet_test_bit(RECVERR, sk)) 1125 return ip_icmp_error(sk, skb, err, port, info, payload); 1126#if IS_ENABLED(CONFIG_IPV6) 1127 } else { 1128 if (inet6_test_bit(RECVERR6, sk)) 1129 return ipv6_icmp_error(sk, skb, err, port, info, payload); 1130#endif 1131 } 1132} 1133 1134/************************************************************************ 1135 * Transmit handling 1136 ***********************************************************************/ 1137 1138/* Build an L2TP header for the session into the buffer provided. 1139 */ 1140static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) 1141{ 1142 struct l2tp_tunnel *tunnel = session->tunnel; 1143 __be16 *bufp = buf; 1144 __be16 *optr = buf; 1145 u16 flags = L2TP_HDR_VER_2; 1146 u32 tunnel_id = tunnel->peer_tunnel_id; 1147 u32 session_id = session->peer_session_id; 1148 1149 if (session->send_seq) 1150 flags |= L2TP_HDRFLAG_S; 1151 1152 /* Setup L2TP header. */ 1153 *bufp++ = htons(flags); 1154 *bufp++ = htons(tunnel_id); 1155 *bufp++ = htons(session_id); 1156 if (session->send_seq) { 1157 *bufp++ = htons(session->ns); 1158 *bufp++ = 0; 1159 session->ns++; 1160 session->ns &= 0xffff; 1161 trace_session_seqnum_update(session); 1162 } 1163 1164 return bufp - optr; 1165} 1166 1167static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) 1168{ 1169 struct l2tp_tunnel *tunnel = session->tunnel; 1170 char *bufp = buf; 1171 char *optr = bufp; 1172 1173 /* Setup L2TP header. The header differs slightly for UDP and 1174 * IP encapsulations. For UDP, there is 4 bytes of flags. 1175 */ 1176 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { 1177 u16 flags = L2TP_HDR_VER_3; 1178 *((__be16 *)bufp) = htons(flags); 1179 bufp += 2; 1180 *((__be16 *)bufp) = 0; 1181 bufp += 2; 1182 } 1183 1184 *((__be32 *)bufp) = htonl(session->peer_session_id); 1185 bufp += 4; 1186 if (session->cookie_len) { 1187 memcpy(bufp, &session->cookie[0], session->cookie_len); 1188 bufp += session->cookie_len; 1189 } 1190 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 1191 u32 l2h = 0; 1192 1193 if (session->send_seq) { 1194 l2h = 0x40000000 | session->ns; 1195 session->ns++; 1196 session->ns &= 0xffffff; 1197 trace_session_seqnum_update(session); 1198 } 1199 1200 *((__be32 *)bufp) = htonl(l2h); 1201 bufp += 4; 1202 } 1203 1204 return bufp - optr; 1205} 1206 1207/* Queue the packet to IP for output: tunnel socket lock must be held */ 1208static int l2tp_xmit_queue(struct l2tp_tunnel *tunnel, struct sk_buff *skb, struct flowi *fl) 1209{ 1210 int err; 1211 1212 skb->ignore_df = 1; 1213 skb_dst_drop(skb); 1214#if IS_ENABLED(CONFIG_IPV6) 1215 if (l2tp_sk_is_v6(tunnel->sock)) 1216 err = inet6_csk_xmit(tunnel->sock, skb, NULL); 1217 else 1218#endif 1219 err = ip_queue_xmit(tunnel->sock, skb, fl); 1220 1221 return err >= 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP; 1222} 1223 1224static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, unsigned int *len) 1225{ 1226 struct l2tp_tunnel *tunnel = session->tunnel; 1227 unsigned int data_len = skb->len; 1228 struct sock *sk = tunnel->sock; 1229 int headroom, uhlen, udp_len; 1230 int ret = NET_XMIT_SUCCESS; 1231 struct inet_sock *inet; 1232 struct udphdr *uh; 1233 1234 /* Check that there's enough headroom in the skb to insert IP, 1235 * UDP and L2TP headers. If not enough, expand it to 1236 * make room. Adjust truesize. 1237 */ 1238 uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(*uh) : 0; 1239 headroom = NET_SKB_PAD + sizeof(struct iphdr) + uhlen + session->hdr_len; 1240 if (skb_cow_head(skb, headroom)) { 1241 kfree_skb(skb); 1242 return NET_XMIT_DROP; 1243 } 1244 1245 /* Setup L2TP header */ 1246 if (tunnel->version == L2TP_HDR_VER_2) 1247 l2tp_build_l2tpv2_header(session, __skb_push(skb, session->hdr_len)); 1248 else 1249 l2tp_build_l2tpv3_header(session, __skb_push(skb, session->hdr_len)); 1250 1251 /* Reset control buffer */ 1252 memset(skb->cb, 0, sizeof(skb->cb)); 1253 1254 nf_reset_ct(skb); 1255 1256 /* L2TP uses its own lockdep subclass to avoid lockdep splats caused by 1257 * nested socket calls on the same lockdep socket class. This can 1258 * happen when data from a user socket is routed over l2tp, which uses 1259 * another userspace socket. 1260 */ 1261 spin_lock_nested(&sk->sk_lock.slock, L2TP_DEPTH_NESTING); 1262 1263 if (sock_owned_by_user(sk)) { 1264 kfree_skb(skb); 1265 ret = NET_XMIT_DROP; 1266 goto out_unlock; 1267 } 1268 1269 /* The user-space may change the connection status for the user-space 1270 * provided socket at run time: we must check it under the socket lock 1271 */ 1272 if (tunnel->fd >= 0 && sk->sk_state != TCP_ESTABLISHED) { 1273 kfree_skb(skb); 1274 ret = NET_XMIT_DROP; 1275 goto out_unlock; 1276 } 1277 1278 /* Report transmitted length before we add encap header, which keeps 1279 * statistics consistent for both UDP and IP encap tx/rx paths. 1280 */ 1281 *len = skb->len; 1282 1283 inet = inet_sk(sk); 1284 switch (tunnel->encap) { 1285 case L2TP_ENCAPTYPE_UDP: 1286 /* Setup UDP header */ 1287 __skb_push(skb, sizeof(*uh)); 1288 skb_reset_transport_header(skb); 1289 uh = udp_hdr(skb); 1290 uh->source = inet->inet_sport; 1291 uh->dest = inet->inet_dport; 1292 udp_len = uhlen + session->hdr_len + data_len; 1293 if (udp_len > U16_MAX) { 1294 kfree_skb(skb); 1295 ret = NET_XMIT_DROP; 1296 goto out_unlock; 1297 } 1298 uh->len = htons(udp_len); 1299 1300 /* Calculate UDP checksum if configured to do so */ 1301#if IS_ENABLED(CONFIG_IPV6) 1302 if (l2tp_sk_is_v6(sk)) 1303 udp6_set_csum(udp_get_no_check6_tx(sk), 1304 skb, &inet6_sk(sk)->saddr, 1305 &sk->sk_v6_daddr, udp_len); 1306 else 1307#endif 1308 udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr, 1309 inet->inet_daddr, udp_len); 1310 break; 1311 1312 case L2TP_ENCAPTYPE_IP: 1313 break; 1314 } 1315 1316 ret = l2tp_xmit_queue(tunnel, skb, &inet->cork.fl); 1317 1318out_unlock: 1319 spin_unlock(&sk->sk_lock.slock); 1320 1321 return ret; 1322} 1323 1324/* If caller requires the skb to have a ppp header, the header must be 1325 * inserted in the skb data before calling this function. 1326 */ 1327int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) 1328{ 1329 unsigned int len = 0; 1330 int ret; 1331 1332 ret = l2tp_xmit_core(session, skb, &len); 1333 if (ret == NET_XMIT_SUCCESS) { 1334 atomic_long_inc(&session->tunnel->stats.tx_packets); 1335 atomic_long_add(len, &session->tunnel->stats.tx_bytes); 1336 atomic_long_inc(&session->stats.tx_packets); 1337 atomic_long_add(len, &session->stats.tx_bytes); 1338 } else { 1339 atomic_long_inc(&session->tunnel->stats.tx_errors); 1340 atomic_long_inc(&session->stats.tx_errors); 1341 } 1342 return ret; 1343} 1344EXPORT_SYMBOL_GPL(l2tp_xmit_skb); 1345 1346/***************************************************************************** 1347 * Tinnel and session create/destroy. 1348 *****************************************************************************/ 1349 1350/* Remove an l2tp session from l2tp_core's lists. */ 1351static void l2tp_session_unhash(struct l2tp_session *session) 1352{ 1353 struct l2tp_tunnel *tunnel = session->tunnel; 1354 1355 if (tunnel) { 1356 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1357 struct l2tp_session *removed = session; 1358 1359 spin_lock_bh(&tunnel->list_lock); 1360 spin_lock_bh(&pn->l2tp_session_idr_lock); 1361 1362 /* Remove from the per-tunnel list */ 1363 list_del_init(&session->list); 1364 1365 /* Remove from per-net IDR */ 1366 if (tunnel->version == L2TP_HDR_VER_3) { 1367 if (hash_hashed(&session->hlist)) 1368 l2tp_session_collision_del(pn, session); 1369 else 1370 removed = idr_remove(&pn->l2tp_v3_session_idr, 1371 session->session_id); 1372 } else { 1373 u32 session_key = l2tp_v2_session_key(tunnel->tunnel_id, 1374 session->session_id); 1375 removed = idr_remove(&pn->l2tp_v2_session_idr, 1376 session_key); 1377 } 1378 WARN_ON_ONCE(removed && removed != session); 1379 1380 spin_unlock_bh(&pn->l2tp_session_idr_lock); 1381 spin_unlock_bh(&tunnel->list_lock); 1382 } 1383} 1384 1385/* When the tunnel is closed, all the attached sessions need to go too. 1386 */ 1387static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) 1388{ 1389 struct l2tp_session *session; 1390 1391 spin_lock_bh(&tunnel->list_lock); 1392 tunnel->acpt_newsess = false; 1393 list_for_each_entry(session, &tunnel->session_list, list) 1394 l2tp_session_delete(session); 1395 spin_unlock_bh(&tunnel->list_lock); 1396} 1397 1398/* Tunnel socket destroy hook for UDP encapsulation */ 1399static void l2tp_udp_encap_destroy(struct sock *sk) 1400{ 1401 struct l2tp_tunnel *tunnel; 1402 1403 tunnel = l2tp_sk_to_tunnel(sk); 1404 if (tunnel) { 1405 l2tp_tunnel_delete(tunnel); 1406 l2tp_tunnel_put(tunnel); 1407 } 1408} 1409 1410static void l2tp_tunnel_remove(struct net *net, struct l2tp_tunnel *tunnel) 1411{ 1412 struct l2tp_net *pn = l2tp_pernet(net); 1413 1414 spin_lock_bh(&pn->l2tp_tunnel_idr_lock); 1415 idr_remove(&pn->l2tp_tunnel_idr, tunnel->tunnel_id); 1416 spin_unlock_bh(&pn->l2tp_tunnel_idr_lock); 1417} 1418 1419/* Workqueue tunnel deletion function */ 1420static void l2tp_tunnel_del_work(struct work_struct *work) 1421{ 1422 struct l2tp_tunnel *tunnel = container_of(work, struct l2tp_tunnel, 1423 del_work); 1424 1425 l2tp_tunnel_closeall(tunnel); 1426 1427 /* If the tunnel socket was created within the kernel, use 1428 * the sk API to release it here. 1429 */ 1430 if (tunnel->fd < 0) { 1431 struct socket *sock = tunnel->sock->sk_socket; 1432 1433 if (sock) { 1434 kernel_sock_shutdown(sock, SHUT_RDWR); 1435 sock_release(sock); 1436 } 1437 } 1438 1439 l2tp_tunnel_remove(tunnel->l2tp_net, tunnel); 1440 /* drop initial ref */ 1441 l2tp_tunnel_put(tunnel); 1442 1443 /* drop workqueue ref */ 1444 l2tp_tunnel_put(tunnel); 1445} 1446 1447/* Create a socket for the tunnel, if one isn't set up by 1448 * userspace. This is used for static tunnels where there is no 1449 * managing L2TP daemon. 1450 * 1451 * Since we don't want these sockets to keep a namespace alive by 1452 * themselves, we drop the socket's namespace refcount after creation. 1453 * These sockets are freed when the namespace exits using the pernet 1454 * exit hook. 1455 */ 1456static int l2tp_tunnel_sock_create(struct net *net, 1457 u32 tunnel_id, 1458 u32 peer_tunnel_id, 1459 struct l2tp_tunnel_cfg *cfg, 1460 struct socket **sockp) 1461{ 1462 int err = -EINVAL; 1463 struct socket *sock = NULL; 1464 struct udp_port_cfg udp_conf; 1465 1466 switch (cfg->encap) { 1467 case L2TP_ENCAPTYPE_UDP: 1468 memset(&udp_conf, 0, sizeof(udp_conf)); 1469 1470#if IS_ENABLED(CONFIG_IPV6) 1471 if (cfg->local_ip6 && cfg->peer_ip6) { 1472 udp_conf.family = AF_INET6; 1473 memcpy(&udp_conf.local_ip6, cfg->local_ip6, 1474 sizeof(udp_conf.local_ip6)); 1475 memcpy(&udp_conf.peer_ip6, cfg->peer_ip6, 1476 sizeof(udp_conf.peer_ip6)); 1477 udp_conf.use_udp6_tx_checksums = 1478 !cfg->udp6_zero_tx_checksums; 1479 udp_conf.use_udp6_rx_checksums = 1480 !cfg->udp6_zero_rx_checksums; 1481 } else 1482#endif 1483 { 1484 udp_conf.family = AF_INET; 1485 udp_conf.local_ip = cfg->local_ip; 1486 udp_conf.peer_ip = cfg->peer_ip; 1487 udp_conf.use_udp_checksums = cfg->use_udp_checksums; 1488 } 1489 1490 udp_conf.local_udp_port = htons(cfg->local_udp_port); 1491 udp_conf.peer_udp_port = htons(cfg->peer_udp_port); 1492 1493 err = udp_sock_create(net, &udp_conf, &sock); 1494 if (err < 0) 1495 goto out; 1496 1497 break; 1498 1499 case L2TP_ENCAPTYPE_IP: 1500#if IS_ENABLED(CONFIG_IPV6) 1501 if (cfg->local_ip6 && cfg->peer_ip6) { 1502 struct sockaddr_l2tpip6 ip6_addr = {0}; 1503 1504 err = sock_create_kern(net, AF_INET6, SOCK_DGRAM, 1505 IPPROTO_L2TP, &sock); 1506 if (err < 0) 1507 goto out; 1508 1509 ip6_addr.l2tp_family = AF_INET6; 1510 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6, 1511 sizeof(ip6_addr.l2tp_addr)); 1512 ip6_addr.l2tp_conn_id = tunnel_id; 1513 err = kernel_bind(sock, (struct sockaddr_unsized *)&ip6_addr, 1514 sizeof(ip6_addr)); 1515 if (err < 0) 1516 goto out; 1517 1518 ip6_addr.l2tp_family = AF_INET6; 1519 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6, 1520 sizeof(ip6_addr.l2tp_addr)); 1521 ip6_addr.l2tp_conn_id = peer_tunnel_id; 1522 err = kernel_connect(sock, 1523 (struct sockaddr_unsized *)&ip6_addr, 1524 sizeof(ip6_addr), 0); 1525 if (err < 0) 1526 goto out; 1527 } else 1528#endif 1529 { 1530 struct sockaddr_l2tpip ip_addr = {0}; 1531 1532 err = sock_create_kern(net, AF_INET, SOCK_DGRAM, 1533 IPPROTO_L2TP, &sock); 1534 if (err < 0) 1535 goto out; 1536 1537 ip_addr.l2tp_family = AF_INET; 1538 ip_addr.l2tp_addr = cfg->local_ip; 1539 ip_addr.l2tp_conn_id = tunnel_id; 1540 err = kernel_bind(sock, (struct sockaddr_unsized *)&ip_addr, 1541 sizeof(ip_addr)); 1542 if (err < 0) 1543 goto out; 1544 1545 ip_addr.l2tp_family = AF_INET; 1546 ip_addr.l2tp_addr = cfg->peer_ip; 1547 ip_addr.l2tp_conn_id = peer_tunnel_id; 1548 err = kernel_connect(sock, (struct sockaddr_unsized *)&ip_addr, 1549 sizeof(ip_addr), 0); 1550 if (err < 0) 1551 goto out; 1552 } 1553 break; 1554 1555 default: 1556 goto out; 1557 } 1558 1559out: 1560 *sockp = sock; 1561 if (err < 0 && sock) { 1562 kernel_sock_shutdown(sock, SHUT_RDWR); 1563 sock_release(sock); 1564 *sockp = NULL; 1565 } 1566 1567 return err; 1568} 1569 1570int l2tp_tunnel_create(int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, 1571 struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp) 1572{ 1573 struct l2tp_tunnel *tunnel = NULL; 1574 int err; 1575 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; 1576 1577 if (cfg) 1578 encap = cfg->encap; 1579 1580 tunnel = kzalloc(sizeof(*tunnel), GFP_KERNEL); 1581 if (!tunnel) { 1582 err = -ENOMEM; 1583 goto err; 1584 } 1585 1586 tunnel->version = version; 1587 tunnel->tunnel_id = tunnel_id; 1588 tunnel->peer_tunnel_id = peer_tunnel_id; 1589 1590 sprintf(&tunnel->name[0], "tunl %u", tunnel_id); 1591 spin_lock_init(&tunnel->list_lock); 1592 tunnel->acpt_newsess = true; 1593 INIT_LIST_HEAD(&tunnel->session_list); 1594 1595 tunnel->encap = encap; 1596 1597 refcount_set(&tunnel->ref_count, 1); 1598 tunnel->fd = fd; 1599 1600 /* Init delete workqueue struct */ 1601 INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work); 1602 1603 err = 0; 1604err: 1605 if (tunnelp) 1606 *tunnelp = tunnel; 1607 1608 return err; 1609} 1610EXPORT_SYMBOL_GPL(l2tp_tunnel_create); 1611 1612static int l2tp_validate_socket(const struct sock *sk, const struct net *net, 1613 enum l2tp_encap_type encap) 1614{ 1615 struct l2tp_tunnel *tunnel; 1616 1617 if (!net_eq(sock_net(sk), net)) 1618 return -EINVAL; 1619 1620 if (sk->sk_type != SOCK_DGRAM) 1621 return -EPROTONOSUPPORT; 1622 1623 if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6) 1624 return -EPROTONOSUPPORT; 1625 1626 if ((encap == L2TP_ENCAPTYPE_UDP && sk->sk_protocol != IPPROTO_UDP) || 1627 (encap == L2TP_ENCAPTYPE_IP && sk->sk_protocol != IPPROTO_L2TP)) 1628 return -EPROTONOSUPPORT; 1629 1630 if (encap == L2TP_ENCAPTYPE_UDP && sk->sk_user_data) 1631 return -EBUSY; 1632 1633 tunnel = l2tp_sk_to_tunnel(sk); 1634 if (tunnel) { 1635 l2tp_tunnel_put(tunnel); 1636 return -EBUSY; 1637 } 1638 1639 return 0; 1640} 1641 1642int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, 1643 struct l2tp_tunnel_cfg *cfg) 1644{ 1645 struct l2tp_net *pn = l2tp_pernet(net); 1646 u32 tunnel_id = tunnel->tunnel_id; 1647 struct socket *sock; 1648 struct sock *sk; 1649 int ret; 1650 1651 spin_lock_bh(&pn->l2tp_tunnel_idr_lock); 1652 ret = idr_alloc_u32(&pn->l2tp_tunnel_idr, NULL, &tunnel_id, tunnel_id, 1653 GFP_ATOMIC); 1654 spin_unlock_bh(&pn->l2tp_tunnel_idr_lock); 1655 if (ret) 1656 return ret == -ENOSPC ? -EEXIST : ret; 1657 1658 if (tunnel->fd < 0) { 1659 ret = l2tp_tunnel_sock_create(net, tunnel->tunnel_id, 1660 tunnel->peer_tunnel_id, cfg, 1661 &sock); 1662 if (ret < 0) 1663 goto err; 1664 } else { 1665 sock = sockfd_lookup(tunnel->fd, &ret); 1666 if (!sock) 1667 goto err; 1668 } 1669 1670 sk = sock->sk; 1671 lock_sock(sk); 1672 write_lock_bh(&sk->sk_callback_lock); 1673 ret = l2tp_validate_socket(sk, net, tunnel->encap); 1674 if (ret < 0) 1675 goto err_inval_sock; 1676 write_unlock_bh(&sk->sk_callback_lock); 1677 1678 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { 1679 struct udp_tunnel_sock_cfg udp_cfg = { 1680 .encap_type = UDP_ENCAP_L2TPINUDP, 1681 .encap_rcv = l2tp_udp_encap_recv, 1682 .encap_err_rcv = l2tp_udp_encap_err_recv, 1683 .encap_destroy = l2tp_udp_encap_destroy, 1684 }; 1685 1686 setup_udp_tunnel_sock(net, sock, &udp_cfg); 1687 } 1688 1689 sk->sk_allocation = GFP_ATOMIC; 1690 release_sock(sk); 1691 1692 sock_hold(sk); 1693 tunnel->sock = sk; 1694 tunnel->l2tp_net = net; 1695 1696 spin_lock_bh(&pn->l2tp_tunnel_idr_lock); 1697 idr_replace(&pn->l2tp_tunnel_idr, tunnel, tunnel->tunnel_id); 1698 spin_unlock_bh(&pn->l2tp_tunnel_idr_lock); 1699 1700 trace_register_tunnel(tunnel); 1701 1702 if (tunnel->fd >= 0) 1703 sockfd_put(sock); 1704 1705 return 0; 1706 1707err_inval_sock: 1708 write_unlock_bh(&sk->sk_callback_lock); 1709 release_sock(sk); 1710 1711 if (tunnel->fd < 0) 1712 sock_release(sock); 1713 else 1714 sockfd_put(sock); 1715err: 1716 l2tp_tunnel_remove(net, tunnel); 1717 return ret; 1718} 1719EXPORT_SYMBOL_GPL(l2tp_tunnel_register); 1720 1721/* This function is used by the netlink TUNNEL_DELETE command. 1722 */ 1723void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) 1724{ 1725 if (!test_and_set_bit(0, &tunnel->dead)) { 1726 trace_delete_tunnel(tunnel); 1727 refcount_inc(&tunnel->ref_count); 1728 queue_work(l2tp_wq, &tunnel->del_work); 1729 } 1730} 1731EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); 1732 1733void l2tp_session_delete(struct l2tp_session *session) 1734{ 1735 if (!test_and_set_bit(0, &session->dead)) { 1736 trace_delete_session(session); 1737 refcount_inc(&session->ref_count); 1738 queue_work(l2tp_wq, &session->del_work); 1739 } 1740} 1741EXPORT_SYMBOL_GPL(l2tp_session_delete); 1742 1743/* Workqueue session deletion function */ 1744static void l2tp_session_del_work(struct work_struct *work) 1745{ 1746 struct l2tp_session *session = container_of(work, struct l2tp_session, 1747 del_work); 1748 1749 l2tp_session_unhash(session); 1750 l2tp_session_queue_purge(session); 1751 if (session->session_close) 1752 (*session->session_close)(session); 1753 1754 /* drop initial ref */ 1755 l2tp_session_put(session); 1756 1757 /* drop workqueue ref */ 1758 l2tp_session_put(session); 1759} 1760 1761/* We come here whenever a session's send_seq, cookie_len or 1762 * l2specific_type parameters are set. 1763 */ 1764void l2tp_session_set_header_len(struct l2tp_session *session, int version, 1765 enum l2tp_encap_type encap) 1766{ 1767 if (version == L2TP_HDR_VER_2) { 1768 session->hdr_len = 6; 1769 if (session->send_seq) 1770 session->hdr_len += 4; 1771 } else { 1772 session->hdr_len = 4 + session->cookie_len; 1773 session->hdr_len += l2tp_get_l2specific_len(session); 1774 if (encap == L2TP_ENCAPTYPE_UDP) 1775 session->hdr_len += 4; 1776 } 1777} 1778EXPORT_SYMBOL_GPL(l2tp_session_set_header_len); 1779 1780struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, 1781 u32 peer_session_id, struct l2tp_session_cfg *cfg) 1782{ 1783 struct l2tp_session *session; 1784 1785 session = kzalloc(sizeof(*session) + priv_size, GFP_KERNEL); 1786 if (session) { 1787 session->magic = L2TP_SESSION_MAGIC; 1788 1789 session->session_id = session_id; 1790 session->peer_session_id = peer_session_id; 1791 session->nr = 0; 1792 if (tunnel->version == L2TP_HDR_VER_2) 1793 session->nr_max = 0xffff; 1794 else 1795 session->nr_max = 0xffffff; 1796 session->nr_window_size = session->nr_max / 2; 1797 session->nr_oos_count_max = 4; 1798 1799 /* Use NR of first received packet */ 1800 session->reorder_skip = 1; 1801 1802 sprintf(&session->name[0], "sess %u/%u", 1803 tunnel->tunnel_id, session->session_id); 1804 1805 skb_queue_head_init(&session->reorder_q); 1806 1807 session->hlist_key = l2tp_v3_session_hashkey(tunnel->sock, session->session_id); 1808 INIT_HLIST_NODE(&session->hlist); 1809 INIT_LIST_HEAD(&session->clist); 1810 INIT_LIST_HEAD(&session->list); 1811 INIT_WORK(&session->del_work, l2tp_session_del_work); 1812 1813 if (cfg) { 1814 session->pwtype = cfg->pw_type; 1815 session->send_seq = cfg->send_seq; 1816 session->recv_seq = cfg->recv_seq; 1817 session->lns_mode = cfg->lns_mode; 1818 session->reorder_timeout = cfg->reorder_timeout; 1819 session->l2specific_type = cfg->l2specific_type; 1820 session->cookie_len = cfg->cookie_len; 1821 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); 1822 session->peer_cookie_len = cfg->peer_cookie_len; 1823 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); 1824 } 1825 1826 l2tp_session_set_header_len(session, tunnel->version, tunnel->encap); 1827 1828 refcount_set(&session->ref_count, 1); 1829 1830 return session; 1831 } 1832 1833 return ERR_PTR(-ENOMEM); 1834} 1835EXPORT_SYMBOL_GPL(l2tp_session_create); 1836 1837/***************************************************************************** 1838 * Init and cleanup 1839 *****************************************************************************/ 1840 1841static __net_init int l2tp_init_net(struct net *net) 1842{ 1843 struct l2tp_net *pn = net_generic(net, l2tp_net_id); 1844 1845 idr_init(&pn->l2tp_tunnel_idr); 1846 spin_lock_init(&pn->l2tp_tunnel_idr_lock); 1847 1848 idr_init(&pn->l2tp_v2_session_idr); 1849 idr_init(&pn->l2tp_v3_session_idr); 1850 spin_lock_init(&pn->l2tp_session_idr_lock); 1851 1852 return 0; 1853} 1854 1855static __net_exit void l2tp_pre_exit_net(struct net *net) 1856{ 1857 struct l2tp_net *pn = l2tp_pernet(net); 1858 struct l2tp_tunnel *tunnel = NULL; 1859 unsigned long tunnel_id, tmp; 1860 1861 rcu_read_lock_bh(); 1862 idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) { 1863 if (tunnel) 1864 l2tp_tunnel_delete(tunnel); 1865 } 1866 rcu_read_unlock_bh(); 1867 1868 if (l2tp_wq) { 1869 /* Run all TUNNEL_DELETE work items just queued. */ 1870 __flush_workqueue(l2tp_wq); 1871 1872 /* Each TUNNEL_DELETE work item will queue a SESSION_DELETE 1873 * work item for each session in the tunnel. Flush the 1874 * workqueue again to process these. 1875 */ 1876 __flush_workqueue(l2tp_wq); 1877 } 1878} 1879 1880static int l2tp_idr_item_unexpected(int id, void *p, void *data) 1881{ 1882 const char *idr_name = data; 1883 1884 pr_err("l2tp: %s IDR not empty at net %d exit\n", idr_name, id); 1885 WARN_ON_ONCE(1); 1886 return 1; 1887} 1888 1889static __net_exit void l2tp_exit_net(struct net *net) 1890{ 1891 struct l2tp_net *pn = l2tp_pernet(net); 1892 1893 /* Our per-net IDRs should be empty. Check that is so, to 1894 * help catch cleanup races or refcnt leaks. 1895 */ 1896 idr_for_each(&pn->l2tp_v2_session_idr, l2tp_idr_item_unexpected, 1897 "v2_session"); 1898 idr_for_each(&pn->l2tp_v3_session_idr, l2tp_idr_item_unexpected, 1899 "v3_session"); 1900 idr_for_each(&pn->l2tp_tunnel_idr, l2tp_idr_item_unexpected, 1901 "tunnel"); 1902 1903 idr_destroy(&pn->l2tp_v2_session_idr); 1904 idr_destroy(&pn->l2tp_v3_session_idr); 1905 idr_destroy(&pn->l2tp_tunnel_idr); 1906} 1907 1908static struct pernet_operations l2tp_net_ops = { 1909 .init = l2tp_init_net, 1910 .exit = l2tp_exit_net, 1911 .pre_exit = l2tp_pre_exit_net, 1912 .id = &l2tp_net_id, 1913 .size = sizeof(struct l2tp_net), 1914}; 1915 1916static int __init l2tp_init(void) 1917{ 1918 int rc = 0; 1919 1920 rc = register_pernet_device(&l2tp_net_ops); 1921 if (rc) 1922 goto out; 1923 1924 l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0); 1925 if (!l2tp_wq) { 1926 pr_err("alloc_workqueue failed\n"); 1927 unregister_pernet_device(&l2tp_net_ops); 1928 rc = -ENOMEM; 1929 goto out; 1930 } 1931 1932 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION); 1933 1934out: 1935 return rc; 1936} 1937 1938static void __exit l2tp_exit(void) 1939{ 1940 unregister_pernet_device(&l2tp_net_ops); 1941 if (l2tp_wq) { 1942 destroy_workqueue(l2tp_wq); 1943 l2tp_wq = NULL; 1944 } 1945} 1946 1947module_init(l2tp_init); 1948module_exit(l2tp_exit); 1949 1950MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 1951MODULE_DESCRIPTION("L2TP core"); 1952MODULE_LICENSE("GPL"); 1953MODULE_VERSION(L2TP_DRV_VERSION);
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