1 /* 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 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License version 2 as 18 * published by the Free Software Foundation. 19 */ 20 21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 22 23 #include <linux/module.h> 24 #include <linux/string.h> 25 #include <linux/list.h> 26 #include <linux/rculist.h> 27 #include <linux/uaccess.h> 28 29 #include <linux/kernel.h> 30 #include <linux/spinlock.h> 31 #include <linux/kthread.h> 32 #include <linux/sched.h> 33 #include <linux/slab.h> 34 #include <linux/errno.h> 35 #include <linux/jiffies.h> 36 37 #include <linux/netdevice.h> 38 #include <linux/net.h> 39 #include <linux/inetdevice.h> 40 #include <linux/skbuff.h> 41 #include <linux/init.h> 42 #include <linux/in.h> 43 #include <linux/ip.h> 44 #include <linux/udp.h> 45 #include <linux/l2tp.h> 46 #include <linux/hash.h> 47 #include <linux/sort.h> 48 #include <linux/file.h> 49 #include <linux/nsproxy.h> 50 #include <net/net_namespace.h> 51 #include <net/netns/generic.h> 52 #include <net/dst.h> 53 #include <net/ip.h> 54 #include <net/udp.h> 55 #include <net/udp_tunnel.h> 56 #include <net/inet_common.h> 57 #include <net/xfrm.h> 58 #include <net/protocol.h> 59 #include <net/inet6_connection_sock.h> 60 #include <net/inet_ecn.h> 61 #include <net/ip6_route.h> 62 #include <net/ip6_checksum.h> 63 64 #include <asm/byteorder.h> 65 #include <linux/atomic.h> 66 67 #include "l2tp_core.h" 68 69 #define L2TP_DRV_VERSION "V2.0" 70 71 /* L2TP header constants */ 72 #define L2TP_HDRFLAG_T 0x8000 73 #define L2TP_HDRFLAG_L 0x4000 74 #define L2TP_HDRFLAG_S 0x0800 75 #define L2TP_HDRFLAG_O 0x0200 76 #define L2TP_HDRFLAG_P 0x0100 77 78 #define L2TP_HDR_VER_MASK 0x000F 79 #define L2TP_HDR_VER_2 0x0002 80 #define L2TP_HDR_VER_3 0x0003 81 82 /* L2TPv3 default L2-specific sublayer */ 83 #define L2TP_SLFLAG_S 0x40000000 84 #define L2TP_SL_SEQ_MASK 0x00ffffff 85 86 #define L2TP_HDR_SIZE_SEQ 10 87 #define L2TP_HDR_SIZE_NOSEQ 6 88 89 /* Default trace flags */ 90 #define L2TP_DEFAULT_DEBUG_FLAGS 0 91 92 /* Private data stored for received packets in the skb. 93 */ 94 struct l2tp_skb_cb { 95 u32 ns; 96 u16 has_seq; 97 u16 length; 98 unsigned long expires; 99 }; 100 101 #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) 102 103 static atomic_t l2tp_tunnel_count; 104 static atomic_t l2tp_session_count; 105 static struct workqueue_struct *l2tp_wq; 106 107 /* per-net private data for this module */ 108 static unsigned int l2tp_net_id; 109 struct l2tp_net { 110 struct list_head l2tp_tunnel_list; 111 spinlock_t l2tp_tunnel_list_lock; 112 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2]; 113 spinlock_t l2tp_session_hlist_lock; 114 }; 115 116 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); 117 118 static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk) 119 { 120 return sk->sk_user_data; 121 } 122 123 static inline struct l2tp_net *l2tp_pernet(const struct net *net) 124 { 125 BUG_ON(!net); 126 127 return net_generic(net, l2tp_net_id); 128 } 129 130 /* Tunnel reference counts. Incremented per session that is added to 131 * the tunnel. 132 */ 133 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel) 134 { 135 refcount_inc(&tunnel->ref_count); 136 } 137 138 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel) 139 { 140 if (refcount_dec_and_test(&tunnel->ref_count)) 141 l2tp_tunnel_free(tunnel); 142 } 143 #ifdef L2TP_REFCNT_DEBUG 144 #define l2tp_tunnel_inc_refcount(_t) \ 145 do { \ 146 pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \ 147 __func__, __LINE__, (_t)->name, \ 148 refcount_read(&_t->ref_count)); \ 149 l2tp_tunnel_inc_refcount_1(_t); \ 150 } while (0) 151 #define l2tp_tunnel_dec_refcount(_t) \ 152 do { \ 153 pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \ 154 __func__, __LINE__, (_t)->name, \ 155 refcount_read(&_t->ref_count)); \ 156 l2tp_tunnel_dec_refcount_1(_t); \ 157 } while (0) 158 #else 159 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t) 160 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t) 161 #endif 162 163 /* Session hash global list for L2TPv3. 164 * The session_id SHOULD be random according to RFC3931, but several 165 * L2TP implementations use incrementing session_ids. So we do a real 166 * hash on the session_id, rather than a simple bitmask. 167 */ 168 static inline struct hlist_head * 169 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id) 170 { 171 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)]; 172 173 } 174 175 /* Lookup the tunnel socket, possibly involving the fs code if the socket is 176 * owned by userspace. A struct sock returned from this function must be 177 * released using l2tp_tunnel_sock_put once you're done with it. 178 */ 179 static struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel) 180 { 181 int err = 0; 182 struct socket *sock = NULL; 183 struct sock *sk = NULL; 184 185 if (!tunnel) 186 goto out; 187 188 if (tunnel->fd >= 0) { 189 /* Socket is owned by userspace, who might be in the process 190 * of closing it. Look the socket up using the fd to ensure 191 * consistency. 192 */ 193 sock = sockfd_lookup(tunnel->fd, &err); 194 if (sock) 195 sk = sock->sk; 196 } else { 197 /* Socket is owned by kernelspace */ 198 sk = tunnel->sock; 199 sock_hold(sk); 200 } 201 202 out: 203 return sk; 204 } 205 206 /* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */ 207 static void l2tp_tunnel_sock_put(struct sock *sk) 208 { 209 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); 210 if (tunnel) { 211 if (tunnel->fd >= 0) { 212 /* Socket is owned by userspace */ 213 sockfd_put(sk->sk_socket); 214 } 215 sock_put(sk); 216 } 217 sock_put(sk); 218 } 219 220 /* Session hash list. 221 * The session_id SHOULD be random according to RFC2661, but several 222 * L2TP implementations (Cisco and Microsoft) use incrementing 223 * session_ids. So we do a real hash on the session_id, rather than a 224 * simple bitmask. 225 */ 226 static inline struct hlist_head * 227 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) 228 { 229 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; 230 } 231 232 /* Lookup a session. A new reference is held on the returned session. 233 * Optionally calls session->ref() too if do_ref is true. 234 */ 235 struct l2tp_session *l2tp_session_get(const struct net *net, 236 struct l2tp_tunnel *tunnel, 237 u32 session_id, bool do_ref) 238 { 239 struct hlist_head *session_list; 240 struct l2tp_session *session; 241 242 if (!tunnel) { 243 struct l2tp_net *pn = l2tp_pernet(net); 244 245 session_list = l2tp_session_id_hash_2(pn, session_id); 246 247 rcu_read_lock_bh(); 248 hlist_for_each_entry_rcu(session, session_list, global_hlist) { 249 if (session->session_id == session_id) { 250 l2tp_session_inc_refcount(session); 251 if (do_ref && session->ref) 252 session->ref(session); 253 rcu_read_unlock_bh(); 254 255 return session; 256 } 257 } 258 rcu_read_unlock_bh(); 259 260 return NULL; 261 } 262 263 session_list = l2tp_session_id_hash(tunnel, session_id); 264 read_lock_bh(&tunnel->hlist_lock); 265 hlist_for_each_entry(session, session_list, hlist) { 266 if (session->session_id == session_id) { 267 l2tp_session_inc_refcount(session); 268 if (do_ref && session->ref) 269 session->ref(session); 270 read_unlock_bh(&tunnel->hlist_lock); 271 272 return session; 273 } 274 } 275 read_unlock_bh(&tunnel->hlist_lock); 276 277 return NULL; 278 } 279 EXPORT_SYMBOL_GPL(l2tp_session_get); 280 281 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth, 282 bool do_ref) 283 { 284 int hash; 285 struct l2tp_session *session; 286 int count = 0; 287 288 read_lock_bh(&tunnel->hlist_lock); 289 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { 290 hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) { 291 if (++count > nth) { 292 l2tp_session_inc_refcount(session); 293 if (do_ref && session->ref) 294 session->ref(session); 295 read_unlock_bh(&tunnel->hlist_lock); 296 return session; 297 } 298 } 299 } 300 301 read_unlock_bh(&tunnel->hlist_lock); 302 303 return NULL; 304 } 305 EXPORT_SYMBOL_GPL(l2tp_session_get_nth); 306 307 /* Lookup a session by interface name. 308 * This is very inefficient but is only used by management interfaces. 309 */ 310 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, 311 const char *ifname, 312 bool do_ref) 313 { 314 struct l2tp_net *pn = l2tp_pernet(net); 315 int hash; 316 struct l2tp_session *session; 317 318 rcu_read_lock_bh(); 319 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) { 320 hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) { 321 if (!strcmp(session->ifname, ifname)) { 322 l2tp_session_inc_refcount(session); 323 if (do_ref && session->ref) 324 session->ref(session); 325 rcu_read_unlock_bh(); 326 327 return session; 328 } 329 } 330 } 331 332 rcu_read_unlock_bh(); 333 334 return NULL; 335 } 336 EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname); 337 338 static int l2tp_session_add_to_tunnel(struct l2tp_tunnel *tunnel, 339 struct l2tp_session *session) 340 { 341 struct l2tp_session *session_walk; 342 struct hlist_head *g_head; 343 struct hlist_head *head; 344 struct l2tp_net *pn; 345 346 head = l2tp_session_id_hash(tunnel, session->session_id); 347 348 write_lock_bh(&tunnel->hlist_lock); 349 hlist_for_each_entry(session_walk, head, hlist) 350 if (session_walk->session_id == session->session_id) 351 goto exist; 352 353 if (tunnel->version == L2TP_HDR_VER_3) { 354 pn = l2tp_pernet(tunnel->l2tp_net); 355 g_head = l2tp_session_id_hash_2(l2tp_pernet(tunnel->l2tp_net), 356 session->session_id); 357 358 spin_lock_bh(&pn->l2tp_session_hlist_lock); 359 hlist_for_each_entry(session_walk, g_head, global_hlist) 360 if (session_walk->session_id == session->session_id) 361 goto exist_glob; 362 363 hlist_add_head_rcu(&session->global_hlist, g_head); 364 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 365 } 366 367 hlist_add_head(&session->hlist, head); 368 write_unlock_bh(&tunnel->hlist_lock); 369 370 return 0; 371 372 exist_glob: 373 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 374 exist: 375 write_unlock_bh(&tunnel->hlist_lock); 376 377 return -EEXIST; 378 } 379 380 /* Lookup a tunnel by id 381 */ 382 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id) 383 { 384 struct l2tp_tunnel *tunnel; 385 struct l2tp_net *pn = l2tp_pernet(net); 386 387 rcu_read_lock_bh(); 388 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 389 if (tunnel->tunnel_id == tunnel_id) { 390 rcu_read_unlock_bh(); 391 return tunnel; 392 } 393 } 394 rcu_read_unlock_bh(); 395 396 return NULL; 397 } 398 EXPORT_SYMBOL_GPL(l2tp_tunnel_find); 399 400 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth) 401 { 402 struct l2tp_net *pn = l2tp_pernet(net); 403 struct l2tp_tunnel *tunnel; 404 int count = 0; 405 406 rcu_read_lock_bh(); 407 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 408 if (++count > nth) { 409 rcu_read_unlock_bh(); 410 return tunnel; 411 } 412 } 413 414 rcu_read_unlock_bh(); 415 416 return NULL; 417 } 418 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); 419 420 /***************************************************************************** 421 * Receive data handling 422 *****************************************************************************/ 423 424 /* Queue a skb in order. We come here only if the skb has an L2TP sequence 425 * number. 426 */ 427 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) 428 { 429 struct sk_buff *skbp; 430 struct sk_buff *tmp; 431 u32 ns = L2TP_SKB_CB(skb)->ns; 432 433 spin_lock_bh(&session->reorder_q.lock); 434 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { 435 if (L2TP_SKB_CB(skbp)->ns > ns) { 436 __skb_queue_before(&session->reorder_q, skbp, skb); 437 l2tp_dbg(session, L2TP_MSG_SEQ, 438 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", 439 session->name, ns, L2TP_SKB_CB(skbp)->ns, 440 skb_queue_len(&session->reorder_q)); 441 atomic_long_inc(&session->stats.rx_oos_packets); 442 goto out; 443 } 444 } 445 446 __skb_queue_tail(&session->reorder_q, skb); 447 448 out: 449 spin_unlock_bh(&session->reorder_q.lock); 450 } 451 452 /* Dequeue a single skb. 453 */ 454 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) 455 { 456 struct l2tp_tunnel *tunnel = session->tunnel; 457 int length = L2TP_SKB_CB(skb)->length; 458 459 /* We're about to requeue the skb, so return resources 460 * to its current owner (a socket receive buffer). 461 */ 462 skb_orphan(skb); 463 464 atomic_long_inc(&tunnel->stats.rx_packets); 465 atomic_long_add(length, &tunnel->stats.rx_bytes); 466 atomic_long_inc(&session->stats.rx_packets); 467 atomic_long_add(length, &session->stats.rx_bytes); 468 469 if (L2TP_SKB_CB(skb)->has_seq) { 470 /* Bump our Nr */ 471 session->nr++; 472 session->nr &= session->nr_max; 473 474 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n", 475 session->name, session->nr); 476 } 477 478 /* call private receive handler */ 479 if (session->recv_skb != NULL) 480 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); 481 else 482 kfree_skb(skb); 483 484 if (session->deref) 485 (*session->deref)(session); 486 } 487 488 /* Dequeue skbs from the session's reorder_q, subject to packet order. 489 * Skbs that have been in the queue for too long are simply discarded. 490 */ 491 static void l2tp_recv_dequeue(struct l2tp_session *session) 492 { 493 struct sk_buff *skb; 494 struct sk_buff *tmp; 495 496 /* If the pkt at the head of the queue has the nr that we 497 * expect to send up next, dequeue it and any other 498 * in-sequence packets behind it. 499 */ 500 start: 501 spin_lock_bh(&session->reorder_q.lock); 502 skb_queue_walk_safe(&session->reorder_q, skb, tmp) { 503 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { 504 atomic_long_inc(&session->stats.rx_seq_discards); 505 atomic_long_inc(&session->stats.rx_errors); 506 l2tp_dbg(session, L2TP_MSG_SEQ, 507 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n", 508 session->name, L2TP_SKB_CB(skb)->ns, 509 L2TP_SKB_CB(skb)->length, session->nr, 510 skb_queue_len(&session->reorder_q)); 511 session->reorder_skip = 1; 512 __skb_unlink(skb, &session->reorder_q); 513 kfree_skb(skb); 514 if (session->deref) 515 (*session->deref)(session); 516 continue; 517 } 518 519 if (L2TP_SKB_CB(skb)->has_seq) { 520 if (session->reorder_skip) { 521 l2tp_dbg(session, L2TP_MSG_SEQ, 522 "%s: advancing nr to next pkt: %u -> %u", 523 session->name, session->nr, 524 L2TP_SKB_CB(skb)->ns); 525 session->reorder_skip = 0; 526 session->nr = L2TP_SKB_CB(skb)->ns; 527 } 528 if (L2TP_SKB_CB(skb)->ns != session->nr) { 529 l2tp_dbg(session, L2TP_MSG_SEQ, 530 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n", 531 session->name, L2TP_SKB_CB(skb)->ns, 532 L2TP_SKB_CB(skb)->length, session->nr, 533 skb_queue_len(&session->reorder_q)); 534 goto out; 535 } 536 } 537 __skb_unlink(skb, &session->reorder_q); 538 539 /* Process the skb. We release the queue lock while we 540 * do so to let other contexts process the queue. 541 */ 542 spin_unlock_bh(&session->reorder_q.lock); 543 l2tp_recv_dequeue_skb(session, skb); 544 goto start; 545 } 546 547 out: 548 spin_unlock_bh(&session->reorder_q.lock); 549 } 550 551 static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr) 552 { 553 u32 nws; 554 555 if (nr >= session->nr) 556 nws = nr - session->nr; 557 else 558 nws = (session->nr_max + 1) - (session->nr - nr); 559 560 return nws < session->nr_window_size; 561 } 562 563 /* If packet has sequence numbers, queue it if acceptable. Returns 0 if 564 * acceptable, else non-zero. 565 */ 566 static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb) 567 { 568 if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) { 569 /* Packet sequence number is outside allowed window. 570 * Discard it. 571 */ 572 l2tp_dbg(session, L2TP_MSG_SEQ, 573 "%s: pkt %u len %d discarded, outside window, nr=%u\n", 574 session->name, L2TP_SKB_CB(skb)->ns, 575 L2TP_SKB_CB(skb)->length, session->nr); 576 goto discard; 577 } 578 579 if (session->reorder_timeout != 0) { 580 /* Packet reordering enabled. Add skb to session's 581 * reorder queue, in order of ns. 582 */ 583 l2tp_recv_queue_skb(session, skb); 584 goto out; 585 } 586 587 /* Packet reordering disabled. Discard out-of-sequence packets, while 588 * tracking the number if in-sequence packets after the first OOS packet 589 * is seen. After nr_oos_count_max in-sequence packets, reset the 590 * sequence number to re-enable packet reception. 591 */ 592 if (L2TP_SKB_CB(skb)->ns == session->nr) { 593 skb_queue_tail(&session->reorder_q, skb); 594 } else { 595 u32 nr_oos = L2TP_SKB_CB(skb)->ns; 596 u32 nr_next = (session->nr_oos + 1) & session->nr_max; 597 598 if (nr_oos == nr_next) 599 session->nr_oos_count++; 600 else 601 session->nr_oos_count = 0; 602 603 session->nr_oos = nr_oos; 604 if (session->nr_oos_count > session->nr_oos_count_max) { 605 session->reorder_skip = 1; 606 l2tp_dbg(session, L2TP_MSG_SEQ, 607 "%s: %d oos packets received. Resetting sequence numbers\n", 608 session->name, session->nr_oos_count); 609 } 610 if (!session->reorder_skip) { 611 atomic_long_inc(&session->stats.rx_seq_discards); 612 l2tp_dbg(session, L2TP_MSG_SEQ, 613 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n", 614 session->name, L2TP_SKB_CB(skb)->ns, 615 L2TP_SKB_CB(skb)->length, session->nr, 616 skb_queue_len(&session->reorder_q)); 617 goto discard; 618 } 619 skb_queue_tail(&session->reorder_q, skb); 620 } 621 622 out: 623 return 0; 624 625 discard: 626 return 1; 627 } 628 629 /* Do receive processing of L2TP data frames. We handle both L2TPv2 630 * and L2TPv3 data frames here. 631 * 632 * L2TPv2 Data Message Header 633 * 634 * 0 1 2 3 635 * 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 1 636 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 637 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | 638 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 639 * | Tunnel ID | Session ID | 640 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 641 * | Ns (opt) | Nr (opt) | 642 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 643 * | Offset Size (opt) | Offset pad... (opt) 644 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 645 * 646 * Data frames are marked by T=0. All other fields are the same as 647 * those in L2TP control frames. 648 * 649 * L2TPv3 Data Message Header 650 * 651 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 652 * | L2TP Session Header | 653 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 654 * | L2-Specific Sublayer | 655 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 656 * | Tunnel Payload ... 657 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 658 * 659 * L2TPv3 Session Header Over IP 660 * 661 * 0 1 2 3 662 * 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 1 663 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 664 * | Session ID | 665 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 666 * | Cookie (optional, maximum 64 bits)... 667 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 668 * | 669 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 670 * 671 * L2TPv3 L2-Specific Sublayer Format 672 * 673 * 0 1 2 3 674 * 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 1 675 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 676 * |x|S|x|x|x|x|x|x| Sequence Number | 677 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 678 * 679 * Cookie value, sublayer format and offset (pad) are negotiated with 680 * the peer when the session is set up. Unlike L2TPv2, we do not need 681 * to parse the packet header to determine if optional fields are 682 * present. 683 * 684 * Caller must already have parsed the frame and determined that it is 685 * a data (not control) frame before coming here. Fields up to the 686 * session-id have already been parsed and ptr points to the data 687 * after the session-id. 688 * 689 * session->ref() must have been called prior to l2tp_recv_common(). 690 * session->deref() will be called automatically after skb is processed. 691 */ 692 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 693 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 694 int length, int (*payload_hook)(struct sk_buff *skb)) 695 { 696 struct l2tp_tunnel *tunnel = session->tunnel; 697 int offset; 698 u32 ns, nr; 699 700 /* Parse and check optional cookie */ 701 if (session->peer_cookie_len > 0) { 702 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { 703 l2tp_info(tunnel, L2TP_MSG_DATA, 704 "%s: cookie mismatch (%u/%u). Discarding.\n", 705 tunnel->name, tunnel->tunnel_id, 706 session->session_id); 707 atomic_long_inc(&session->stats.rx_cookie_discards); 708 goto discard; 709 } 710 ptr += session->peer_cookie_len; 711 } 712 713 /* Handle the optional sequence numbers. Sequence numbers are 714 * in different places for L2TPv2 and L2TPv3. 715 * 716 * If we are the LAC, enable/disable sequence numbers under 717 * the control of the LNS. If no sequence numbers present but 718 * we were expecting them, discard frame. 719 */ 720 ns = nr = 0; 721 L2TP_SKB_CB(skb)->has_seq = 0; 722 if (tunnel->version == L2TP_HDR_VER_2) { 723 if (hdrflags & L2TP_HDRFLAG_S) { 724 ns = ntohs(*(__be16 *) ptr); 725 ptr += 2; 726 nr = ntohs(*(__be16 *) ptr); 727 ptr += 2; 728 729 /* Store L2TP info in the skb */ 730 L2TP_SKB_CB(skb)->ns = ns; 731 L2TP_SKB_CB(skb)->has_seq = 1; 732 733 l2tp_dbg(session, L2TP_MSG_SEQ, 734 "%s: recv data ns=%u, nr=%u, session nr=%u\n", 735 session->name, ns, nr, session->nr); 736 } 737 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 738 u32 l2h = ntohl(*(__be32 *) ptr); 739 740 if (l2h & 0x40000000) { 741 ns = l2h & 0x00ffffff; 742 743 /* Store L2TP info in the skb */ 744 L2TP_SKB_CB(skb)->ns = ns; 745 L2TP_SKB_CB(skb)->has_seq = 1; 746 747 l2tp_dbg(session, L2TP_MSG_SEQ, 748 "%s: recv data ns=%u, session nr=%u\n", 749 session->name, ns, session->nr); 750 } 751 } 752 753 /* Advance past L2-specific header, if present */ 754 ptr += session->l2specific_len; 755 756 if (L2TP_SKB_CB(skb)->has_seq) { 757 /* Received a packet with sequence numbers. If we're the LNS, 758 * check if we sre sending sequence numbers and if not, 759 * configure it so. 760 */ 761 if ((!session->lns_mode) && (!session->send_seq)) { 762 l2tp_info(session, L2TP_MSG_SEQ, 763 "%s: requested to enable seq numbers by LNS\n", 764 session->name); 765 session->send_seq = 1; 766 l2tp_session_set_header_len(session, tunnel->version); 767 } 768 } else { 769 /* No sequence numbers. 770 * If user has configured mandatory sequence numbers, discard. 771 */ 772 if (session->recv_seq) { 773 l2tp_warn(session, L2TP_MSG_SEQ, 774 "%s: recv data has no seq numbers when required. Discarding.\n", 775 session->name); 776 atomic_long_inc(&session->stats.rx_seq_discards); 777 goto discard; 778 } 779 780 /* If we're the LAC and we're sending sequence numbers, the 781 * LNS has requested that we no longer send sequence numbers. 782 * If we're the LNS and we're sending sequence numbers, the 783 * LAC is broken. Discard the frame. 784 */ 785 if ((!session->lns_mode) && (session->send_seq)) { 786 l2tp_info(session, L2TP_MSG_SEQ, 787 "%s: requested to disable seq numbers by LNS\n", 788 session->name); 789 session->send_seq = 0; 790 l2tp_session_set_header_len(session, tunnel->version); 791 } else if (session->send_seq) { 792 l2tp_warn(session, L2TP_MSG_SEQ, 793 "%s: recv data has no seq numbers when required. Discarding.\n", 794 session->name); 795 atomic_long_inc(&session->stats.rx_seq_discards); 796 goto discard; 797 } 798 } 799 800 /* Session data offset is handled differently for L2TPv2 and 801 * L2TPv3. For L2TPv2, there is an optional 16-bit value in 802 * the header. For L2TPv3, the offset is negotiated using AVPs 803 * in the session setup control protocol. 804 */ 805 if (tunnel->version == L2TP_HDR_VER_2) { 806 /* If offset bit set, skip it. */ 807 if (hdrflags & L2TP_HDRFLAG_O) { 808 offset = ntohs(*(__be16 *)ptr); 809 ptr += 2 + offset; 810 } 811 } else 812 ptr += session->offset; 813 814 offset = ptr - optr; 815 if (!pskb_may_pull(skb, offset)) 816 goto discard; 817 818 __skb_pull(skb, offset); 819 820 /* If caller wants to process the payload before we queue the 821 * packet, do so now. 822 */ 823 if (payload_hook) 824 if ((*payload_hook)(skb)) 825 goto discard; 826 827 /* Prepare skb for adding to the session's reorder_q. Hold 828 * packets for max reorder_timeout or 1 second if not 829 * reordering. 830 */ 831 L2TP_SKB_CB(skb)->length = length; 832 L2TP_SKB_CB(skb)->expires = jiffies + 833 (session->reorder_timeout ? session->reorder_timeout : HZ); 834 835 /* Add packet to the session's receive queue. Reordering is done here, if 836 * enabled. Saved L2TP protocol info is stored in skb->sb[]. 837 */ 838 if (L2TP_SKB_CB(skb)->has_seq) { 839 if (l2tp_recv_data_seq(session, skb)) 840 goto discard; 841 } else { 842 /* No sequence numbers. Add the skb to the tail of the 843 * reorder queue. This ensures that it will be 844 * delivered after all previous sequenced skbs. 845 */ 846 skb_queue_tail(&session->reorder_q, skb); 847 } 848 849 /* Try to dequeue as many skbs from reorder_q as we can. */ 850 l2tp_recv_dequeue(session); 851 852 return; 853 854 discard: 855 atomic_long_inc(&session->stats.rx_errors); 856 kfree_skb(skb); 857 858 if (session->deref) 859 (*session->deref)(session); 860 } 861 EXPORT_SYMBOL(l2tp_recv_common); 862 863 /* Drop skbs from the session's reorder_q 864 */ 865 int l2tp_session_queue_purge(struct l2tp_session *session) 866 { 867 struct sk_buff *skb = NULL; 868 BUG_ON(!session); 869 BUG_ON(session->magic != L2TP_SESSION_MAGIC); 870 while ((skb = skb_dequeue(&session->reorder_q))) { 871 atomic_long_inc(&session->stats.rx_errors); 872 kfree_skb(skb); 873 if (session->deref) 874 (*session->deref)(session); 875 } 876 return 0; 877 } 878 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge); 879 880 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame 881 * here. The skb is not on a list when we get here. 882 * Returns 0 if the packet was a data packet and was successfully passed on. 883 * Returns 1 if the packet was not a good data packet and could not be 884 * forwarded. All such packets are passed up to userspace to deal with. 885 */ 886 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, 887 int (*payload_hook)(struct sk_buff *skb)) 888 { 889 struct l2tp_session *session = NULL; 890 unsigned char *ptr, *optr; 891 u16 hdrflags; 892 u32 tunnel_id, session_id; 893 u16 version; 894 int length; 895 896 /* UDP has verifed checksum */ 897 898 /* UDP always verifies the packet length. */ 899 __skb_pull(skb, sizeof(struct udphdr)); 900 901 /* Short packet? */ 902 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { 903 l2tp_info(tunnel, L2TP_MSG_DATA, 904 "%s: recv short packet (len=%d)\n", 905 tunnel->name, skb->len); 906 goto error; 907 } 908 909 /* Trace packet contents, if enabled */ 910 if (tunnel->debug & L2TP_MSG_DATA) { 911 length = min(32u, skb->len); 912 if (!pskb_may_pull(skb, length)) 913 goto error; 914 915 pr_debug("%s: recv\n", tunnel->name); 916 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length); 917 } 918 919 /* Point to L2TP header */ 920 optr = ptr = skb->data; 921 922 /* Get L2TP header flags */ 923 hdrflags = ntohs(*(__be16 *) ptr); 924 925 /* Check protocol version */ 926 version = hdrflags & L2TP_HDR_VER_MASK; 927 if (version != tunnel->version) { 928 l2tp_info(tunnel, L2TP_MSG_DATA, 929 "%s: recv protocol version mismatch: got %d expected %d\n", 930 tunnel->name, version, tunnel->version); 931 goto error; 932 } 933 934 /* Get length of L2TP packet */ 935 length = skb->len; 936 937 /* If type is control packet, it is handled by userspace. */ 938 if (hdrflags & L2TP_HDRFLAG_T) { 939 l2tp_dbg(tunnel, L2TP_MSG_DATA, 940 "%s: recv control packet, len=%d\n", 941 tunnel->name, length); 942 goto error; 943 } 944 945 /* Skip flags */ 946 ptr += 2; 947 948 if (tunnel->version == L2TP_HDR_VER_2) { 949 /* If length is present, skip it */ 950 if (hdrflags & L2TP_HDRFLAG_L) 951 ptr += 2; 952 953 /* Extract tunnel and session ID */ 954 tunnel_id = ntohs(*(__be16 *) ptr); 955 ptr += 2; 956 session_id = ntohs(*(__be16 *) ptr); 957 ptr += 2; 958 } else { 959 ptr += 2; /* skip reserved bits */ 960 tunnel_id = tunnel->tunnel_id; 961 session_id = ntohl(*(__be32 *) ptr); 962 ptr += 4; 963 } 964 965 /* Find the session context */ 966 session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id, true); 967 if (!session || !session->recv_skb) { 968 if (session) { 969 if (session->deref) 970 session->deref(session); 971 l2tp_session_dec_refcount(session); 972 } 973 974 /* Not found? Pass to userspace to deal with */ 975 l2tp_info(tunnel, L2TP_MSG_DATA, 976 "%s: no session found (%u/%u). Passing up.\n", 977 tunnel->name, tunnel_id, session_id); 978 goto error; 979 } 980 981 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); 982 l2tp_session_dec_refcount(session); 983 984 return 0; 985 986 error: 987 /* Put UDP header back */ 988 __skb_push(skb, sizeof(struct udphdr)); 989 990 return 1; 991 } 992 993 /* UDP encapsulation receive handler. See net/ipv4/udp.c. 994 * Return codes: 995 * 0 : success. 996 * <0: error 997 * >0: skb should be passed up to userspace as UDP. 998 */ 999 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 1000 { 1001 struct l2tp_tunnel *tunnel; 1002 1003 tunnel = l2tp_sock_to_tunnel(sk); 1004 if (tunnel == NULL) 1005 goto pass_up; 1006 1007 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n", 1008 tunnel->name, skb->len); 1009 1010 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) 1011 goto pass_up_put; 1012 1013 sock_put(sk); 1014 return 0; 1015 1016 pass_up_put: 1017 sock_put(sk); 1018 pass_up: 1019 return 1; 1020 } 1021 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); 1022 1023 /************************************************************************ 1024 * Transmit handling 1025 ***********************************************************************/ 1026 1027 /* Build an L2TP header for the session into the buffer provided. 1028 */ 1029 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) 1030 { 1031 struct l2tp_tunnel *tunnel = session->tunnel; 1032 __be16 *bufp = buf; 1033 __be16 *optr = buf; 1034 u16 flags = L2TP_HDR_VER_2; 1035 u32 tunnel_id = tunnel->peer_tunnel_id; 1036 u32 session_id = session->peer_session_id; 1037 1038 if (session->send_seq) 1039 flags |= L2TP_HDRFLAG_S; 1040 1041 /* Setup L2TP header. */ 1042 *bufp++ = htons(flags); 1043 *bufp++ = htons(tunnel_id); 1044 *bufp++ = htons(session_id); 1045 if (session->send_seq) { 1046 *bufp++ = htons(session->ns); 1047 *bufp++ = 0; 1048 session->ns++; 1049 session->ns &= 0xffff; 1050 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n", 1051 session->name, session->ns); 1052 } 1053 1054 return bufp - optr; 1055 } 1056 1057 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) 1058 { 1059 struct l2tp_tunnel *tunnel = session->tunnel; 1060 char *bufp = buf; 1061 char *optr = bufp; 1062 1063 /* Setup L2TP header. The header differs slightly for UDP and 1064 * IP encapsulations. For UDP, there is 4 bytes of flags. 1065 */ 1066 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { 1067 u16 flags = L2TP_HDR_VER_3; 1068 *((__be16 *) bufp) = htons(flags); 1069 bufp += 2; 1070 *((__be16 *) bufp) = 0; 1071 bufp += 2; 1072 } 1073 1074 *((__be32 *) bufp) = htonl(session->peer_session_id); 1075 bufp += 4; 1076 if (session->cookie_len) { 1077 memcpy(bufp, &session->cookie[0], session->cookie_len); 1078 bufp += session->cookie_len; 1079 } 1080 if (session->l2specific_len) { 1081 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 1082 u32 l2h = 0; 1083 if (session->send_seq) { 1084 l2h = 0x40000000 | session->ns; 1085 session->ns++; 1086 session->ns &= 0xffffff; 1087 l2tp_dbg(session, L2TP_MSG_SEQ, 1088 "%s: updated ns to %u\n", 1089 session->name, session->ns); 1090 } 1091 1092 *((__be32 *) bufp) = htonl(l2h); 1093 } 1094 bufp += session->l2specific_len; 1095 } 1096 if (session->offset) 1097 bufp += session->offset; 1098 1099 return bufp - optr; 1100 } 1101 1102 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, 1103 struct flowi *fl, size_t data_len) 1104 { 1105 struct l2tp_tunnel *tunnel = session->tunnel; 1106 unsigned int len = skb->len; 1107 int error; 1108 1109 /* Debug */ 1110 if (session->send_seq) 1111 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes, ns=%u\n", 1112 session->name, data_len, session->ns - 1); 1113 else 1114 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %zd bytes\n", 1115 session->name, data_len); 1116 1117 if (session->debug & L2TP_MSG_DATA) { 1118 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; 1119 unsigned char *datap = skb->data + uhlen; 1120 1121 pr_debug("%s: xmit\n", session->name); 1122 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, 1123 datap, min_t(size_t, 32, len - uhlen)); 1124 } 1125 1126 /* Queue the packet to IP for output */ 1127 skb->ignore_df = 1; 1128 #if IS_ENABLED(CONFIG_IPV6) 1129 if (tunnel->sock->sk_family == PF_INET6 && !tunnel->v4mapped) 1130 error = inet6_csk_xmit(tunnel->sock, skb, NULL); 1131 else 1132 #endif 1133 error = ip_queue_xmit(tunnel->sock, skb, fl); 1134 1135 /* Update stats */ 1136 if (error >= 0) { 1137 atomic_long_inc(&tunnel->stats.tx_packets); 1138 atomic_long_add(len, &tunnel->stats.tx_bytes); 1139 atomic_long_inc(&session->stats.tx_packets); 1140 atomic_long_add(len, &session->stats.tx_bytes); 1141 } else { 1142 atomic_long_inc(&tunnel->stats.tx_errors); 1143 atomic_long_inc(&session->stats.tx_errors); 1144 } 1145 1146 return 0; 1147 } 1148 1149 /* If caller requires the skb to have a ppp header, the header must be 1150 * inserted in the skb data before calling this function. 1151 */ 1152 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) 1153 { 1154 int data_len = skb->len; 1155 struct l2tp_tunnel *tunnel = session->tunnel; 1156 struct sock *sk = tunnel->sock; 1157 struct flowi *fl; 1158 struct udphdr *uh; 1159 struct inet_sock *inet; 1160 int headroom; 1161 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; 1162 int udp_len; 1163 int ret = NET_XMIT_SUCCESS; 1164 1165 /* Check that there's enough headroom in the skb to insert IP, 1166 * UDP and L2TP headers. If not enough, expand it to 1167 * make room. Adjust truesize. 1168 */ 1169 headroom = NET_SKB_PAD + sizeof(struct iphdr) + 1170 uhlen + hdr_len; 1171 if (skb_cow_head(skb, headroom)) { 1172 kfree_skb(skb); 1173 return NET_XMIT_DROP; 1174 } 1175 1176 /* Setup L2TP header */ 1177 session->build_header(session, __skb_push(skb, hdr_len)); 1178 1179 /* Reset skb netfilter state */ 1180 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 1181 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | 1182 IPSKB_REROUTED); 1183 nf_reset(skb); 1184 1185 bh_lock_sock(sk); 1186 if (sock_owned_by_user(sk)) { 1187 kfree_skb(skb); 1188 ret = NET_XMIT_DROP; 1189 goto out_unlock; 1190 } 1191 1192 /* Get routing info from the tunnel socket */ 1193 skb_dst_drop(skb); 1194 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0))); 1195 1196 inet = inet_sk(sk); 1197 fl = &inet->cork.fl; 1198 switch (tunnel->encap) { 1199 case L2TP_ENCAPTYPE_UDP: 1200 /* Setup UDP header */ 1201 __skb_push(skb, sizeof(*uh)); 1202 skb_reset_transport_header(skb); 1203 uh = udp_hdr(skb); 1204 uh->source = inet->inet_sport; 1205 uh->dest = inet->inet_dport; 1206 udp_len = uhlen + hdr_len + data_len; 1207 uh->len = htons(udp_len); 1208 1209 /* Calculate UDP checksum if configured to do so */ 1210 #if IS_ENABLED(CONFIG_IPV6) 1211 if (sk->sk_family == PF_INET6 && !tunnel->v4mapped) 1212 udp6_set_csum(udp_get_no_check6_tx(sk), 1213 skb, &inet6_sk(sk)->saddr, 1214 &sk->sk_v6_daddr, udp_len); 1215 else 1216 #endif 1217 udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr, 1218 inet->inet_daddr, udp_len); 1219 break; 1220 1221 case L2TP_ENCAPTYPE_IP: 1222 break; 1223 } 1224 1225 l2tp_xmit_core(session, skb, fl, data_len); 1226 out_unlock: 1227 bh_unlock_sock(sk); 1228 1229 return ret; 1230 } 1231 EXPORT_SYMBOL_GPL(l2tp_xmit_skb); 1232 1233 /***************************************************************************** 1234 * Tinnel and session create/destroy. 1235 *****************************************************************************/ 1236 1237 /* Tunnel socket destruct hook. 1238 * The tunnel context is deleted only when all session sockets have been 1239 * closed. 1240 */ 1241 static void l2tp_tunnel_destruct(struct sock *sk) 1242 { 1243 struct l2tp_tunnel *tunnel = l2tp_tunnel(sk); 1244 struct l2tp_net *pn; 1245 1246 if (tunnel == NULL) 1247 goto end; 1248 1249 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name); 1250 1251 1252 /* Disable udp encapsulation */ 1253 switch (tunnel->encap) { 1254 case L2TP_ENCAPTYPE_UDP: 1255 /* No longer an encapsulation socket. See net/ipv4/udp.c */ 1256 (udp_sk(sk))->encap_type = 0; 1257 (udp_sk(sk))->encap_rcv = NULL; 1258 (udp_sk(sk))->encap_destroy = NULL; 1259 break; 1260 case L2TP_ENCAPTYPE_IP: 1261 break; 1262 } 1263 1264 /* Remove hooks into tunnel socket */ 1265 sk->sk_destruct = tunnel->old_sk_destruct; 1266 sk->sk_user_data = NULL; 1267 tunnel->sock = NULL; 1268 1269 /* Remove the tunnel struct from the tunnel list */ 1270 pn = l2tp_pernet(tunnel->l2tp_net); 1271 spin_lock_bh(&pn->l2tp_tunnel_list_lock); 1272 list_del_rcu(&tunnel->list); 1273 spin_unlock_bh(&pn->l2tp_tunnel_list_lock); 1274 atomic_dec(&l2tp_tunnel_count); 1275 1276 l2tp_tunnel_closeall(tunnel); 1277 l2tp_tunnel_dec_refcount(tunnel); 1278 1279 /* Call the original destructor */ 1280 if (sk->sk_destruct) 1281 (*sk->sk_destruct)(sk); 1282 end: 1283 return; 1284 } 1285 1286 /* When the tunnel is closed, all the attached sessions need to go too. 1287 */ 1288 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) 1289 { 1290 int hash; 1291 struct hlist_node *walk; 1292 struct hlist_node *tmp; 1293 struct l2tp_session *session; 1294 1295 BUG_ON(tunnel == NULL); 1296 1297 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n", 1298 tunnel->name); 1299 1300 write_lock_bh(&tunnel->hlist_lock); 1301 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { 1302 again: 1303 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { 1304 session = hlist_entry(walk, struct l2tp_session, hlist); 1305 1306 l2tp_info(session, L2TP_MSG_CONTROL, 1307 "%s: closing session\n", session->name); 1308 1309 hlist_del_init(&session->hlist); 1310 1311 if (session->ref != NULL) 1312 (*session->ref)(session); 1313 1314 write_unlock_bh(&tunnel->hlist_lock); 1315 1316 __l2tp_session_unhash(session); 1317 l2tp_session_queue_purge(session); 1318 1319 if (session->session_close != NULL) 1320 (*session->session_close)(session); 1321 1322 if (session->deref != NULL) 1323 (*session->deref)(session); 1324 1325 l2tp_session_dec_refcount(session); 1326 1327 write_lock_bh(&tunnel->hlist_lock); 1328 1329 /* Now restart from the beginning of this hash 1330 * chain. We always remove a session from the 1331 * list so we are guaranteed to make forward 1332 * progress. 1333 */ 1334 goto again; 1335 } 1336 } 1337 write_unlock_bh(&tunnel->hlist_lock); 1338 } 1339 EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall); 1340 1341 /* Tunnel socket destroy hook for UDP encapsulation */ 1342 static void l2tp_udp_encap_destroy(struct sock *sk) 1343 { 1344 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); 1345 if (tunnel) { 1346 l2tp_tunnel_closeall(tunnel); 1347 sock_put(sk); 1348 } 1349 } 1350 1351 /* Really kill the tunnel. 1352 * Come here only when all sessions have been cleared from the tunnel. 1353 */ 1354 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) 1355 { 1356 BUG_ON(refcount_read(&tunnel->ref_count) != 0); 1357 BUG_ON(tunnel->sock != NULL); 1358 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name); 1359 kfree_rcu(tunnel, rcu); 1360 } 1361 1362 /* Workqueue tunnel deletion function */ 1363 static void l2tp_tunnel_del_work(struct work_struct *work) 1364 { 1365 struct l2tp_tunnel *tunnel = NULL; 1366 struct socket *sock = NULL; 1367 struct sock *sk = NULL; 1368 1369 tunnel = container_of(work, struct l2tp_tunnel, del_work); 1370 1371 l2tp_tunnel_closeall(tunnel); 1372 1373 sk = l2tp_tunnel_sock_lookup(tunnel); 1374 if (!sk) 1375 goto out; 1376 1377 sock = sk->sk_socket; 1378 1379 /* If the tunnel socket was created by userspace, then go through the 1380 * inet layer to shut the socket down, and let userspace close it. 1381 * Otherwise, if we created the socket directly within the kernel, use 1382 * the sk API to release it here. 1383 * In either case the tunnel resources are freed in the socket 1384 * destructor when the tunnel socket goes away. 1385 */ 1386 if (tunnel->fd >= 0) { 1387 if (sock) 1388 inet_shutdown(sock, 2); 1389 } else { 1390 if (sock) { 1391 kernel_sock_shutdown(sock, SHUT_RDWR); 1392 sock_release(sock); 1393 } 1394 } 1395 1396 l2tp_tunnel_sock_put(sk); 1397 out: 1398 l2tp_tunnel_dec_refcount(tunnel); 1399 } 1400 1401 /* Create a socket for the tunnel, if one isn't set up by 1402 * userspace. This is used for static tunnels where there is no 1403 * managing L2TP daemon. 1404 * 1405 * Since we don't want these sockets to keep a namespace alive by 1406 * themselves, we drop the socket's namespace refcount after creation. 1407 * These sockets are freed when the namespace exits using the pernet 1408 * exit hook. 1409 */ 1410 static int l2tp_tunnel_sock_create(struct net *net, 1411 u32 tunnel_id, 1412 u32 peer_tunnel_id, 1413 struct l2tp_tunnel_cfg *cfg, 1414 struct socket **sockp) 1415 { 1416 int err = -EINVAL; 1417 struct socket *sock = NULL; 1418 struct udp_port_cfg udp_conf; 1419 1420 switch (cfg->encap) { 1421 case L2TP_ENCAPTYPE_UDP: 1422 memset(&udp_conf, 0, sizeof(udp_conf)); 1423 1424 #if IS_ENABLED(CONFIG_IPV6) 1425 if (cfg->local_ip6 && cfg->peer_ip6) { 1426 udp_conf.family = AF_INET6; 1427 memcpy(&udp_conf.local_ip6, cfg->local_ip6, 1428 sizeof(udp_conf.local_ip6)); 1429 memcpy(&udp_conf.peer_ip6, cfg->peer_ip6, 1430 sizeof(udp_conf.peer_ip6)); 1431 udp_conf.use_udp6_tx_checksums = 1432 ! cfg->udp6_zero_tx_checksums; 1433 udp_conf.use_udp6_rx_checksums = 1434 ! cfg->udp6_zero_rx_checksums; 1435 } else 1436 #endif 1437 { 1438 udp_conf.family = AF_INET; 1439 udp_conf.local_ip = cfg->local_ip; 1440 udp_conf.peer_ip = cfg->peer_ip; 1441 udp_conf.use_udp_checksums = cfg->use_udp_checksums; 1442 } 1443 1444 udp_conf.local_udp_port = htons(cfg->local_udp_port); 1445 udp_conf.peer_udp_port = htons(cfg->peer_udp_port); 1446 1447 err = udp_sock_create(net, &udp_conf, &sock); 1448 if (err < 0) 1449 goto out; 1450 1451 break; 1452 1453 case L2TP_ENCAPTYPE_IP: 1454 #if IS_ENABLED(CONFIG_IPV6) 1455 if (cfg->local_ip6 && cfg->peer_ip6) { 1456 struct sockaddr_l2tpip6 ip6_addr = {0}; 1457 1458 err = sock_create_kern(net, AF_INET6, SOCK_DGRAM, 1459 IPPROTO_L2TP, &sock); 1460 if (err < 0) 1461 goto out; 1462 1463 ip6_addr.l2tp_family = AF_INET6; 1464 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6, 1465 sizeof(ip6_addr.l2tp_addr)); 1466 ip6_addr.l2tp_conn_id = tunnel_id; 1467 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr, 1468 sizeof(ip6_addr)); 1469 if (err < 0) 1470 goto out; 1471 1472 ip6_addr.l2tp_family = AF_INET6; 1473 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6, 1474 sizeof(ip6_addr.l2tp_addr)); 1475 ip6_addr.l2tp_conn_id = peer_tunnel_id; 1476 err = kernel_connect(sock, 1477 (struct sockaddr *) &ip6_addr, 1478 sizeof(ip6_addr), 0); 1479 if (err < 0) 1480 goto out; 1481 } else 1482 #endif 1483 { 1484 struct sockaddr_l2tpip ip_addr = {0}; 1485 1486 err = sock_create_kern(net, AF_INET, SOCK_DGRAM, 1487 IPPROTO_L2TP, &sock); 1488 if (err < 0) 1489 goto out; 1490 1491 ip_addr.l2tp_family = AF_INET; 1492 ip_addr.l2tp_addr = cfg->local_ip; 1493 ip_addr.l2tp_conn_id = tunnel_id; 1494 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, 1495 sizeof(ip_addr)); 1496 if (err < 0) 1497 goto out; 1498 1499 ip_addr.l2tp_family = AF_INET; 1500 ip_addr.l2tp_addr = cfg->peer_ip; 1501 ip_addr.l2tp_conn_id = peer_tunnel_id; 1502 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, 1503 sizeof(ip_addr), 0); 1504 if (err < 0) 1505 goto out; 1506 } 1507 break; 1508 1509 default: 1510 goto out; 1511 } 1512 1513 out: 1514 *sockp = sock; 1515 if ((err < 0) && sock) { 1516 kernel_sock_shutdown(sock, SHUT_RDWR); 1517 sock_release(sock); 1518 *sockp = NULL; 1519 } 1520 1521 return err; 1522 } 1523 1524 static struct lock_class_key l2tp_socket_class; 1525 1526 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp) 1527 { 1528 struct l2tp_tunnel *tunnel = NULL; 1529 int err; 1530 struct socket *sock = NULL; 1531 struct sock *sk = NULL; 1532 struct l2tp_net *pn; 1533 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; 1534 1535 /* Get the tunnel socket from the fd, which was opened by 1536 * the userspace L2TP daemon. If not specified, create a 1537 * kernel socket. 1538 */ 1539 if (fd < 0) { 1540 err = l2tp_tunnel_sock_create(net, tunnel_id, peer_tunnel_id, 1541 cfg, &sock); 1542 if (err < 0) 1543 goto err; 1544 } else { 1545 sock = sockfd_lookup(fd, &err); 1546 if (!sock) { 1547 pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n", 1548 tunnel_id, fd, err); 1549 err = -EBADF; 1550 goto err; 1551 } 1552 1553 /* Reject namespace mismatches */ 1554 if (!net_eq(sock_net(sock->sk), net)) { 1555 pr_err("tunl %u: netns mismatch\n", tunnel_id); 1556 err = -EINVAL; 1557 goto err; 1558 } 1559 } 1560 1561 sk = sock->sk; 1562 1563 if (cfg != NULL) 1564 encap = cfg->encap; 1565 1566 /* Quick sanity checks */ 1567 switch (encap) { 1568 case L2TP_ENCAPTYPE_UDP: 1569 err = -EPROTONOSUPPORT; 1570 if (sk->sk_protocol != IPPROTO_UDP) { 1571 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n", 1572 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); 1573 goto err; 1574 } 1575 break; 1576 case L2TP_ENCAPTYPE_IP: 1577 err = -EPROTONOSUPPORT; 1578 if (sk->sk_protocol != IPPROTO_L2TP) { 1579 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n", 1580 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP); 1581 goto err; 1582 } 1583 break; 1584 } 1585 1586 /* Check if this socket has already been prepped */ 1587 tunnel = l2tp_tunnel(sk); 1588 if (tunnel != NULL) { 1589 /* This socket has already been prepped */ 1590 err = -EBUSY; 1591 goto err; 1592 } 1593 1594 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); 1595 if (tunnel == NULL) { 1596 err = -ENOMEM; 1597 goto err; 1598 } 1599 1600 tunnel->version = version; 1601 tunnel->tunnel_id = tunnel_id; 1602 tunnel->peer_tunnel_id = peer_tunnel_id; 1603 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; 1604 1605 tunnel->magic = L2TP_TUNNEL_MAGIC; 1606 sprintf(&tunnel->name[0], "tunl %u", tunnel_id); 1607 rwlock_init(&tunnel->hlist_lock); 1608 1609 /* The net we belong to */ 1610 tunnel->l2tp_net = net; 1611 pn = l2tp_pernet(net); 1612 1613 if (cfg != NULL) 1614 tunnel->debug = cfg->debug; 1615 1616 #if IS_ENABLED(CONFIG_IPV6) 1617 if (sk->sk_family == PF_INET6) { 1618 struct ipv6_pinfo *np = inet6_sk(sk); 1619 1620 if (ipv6_addr_v4mapped(&np->saddr) && 1621 ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { 1622 struct inet_sock *inet = inet_sk(sk); 1623 1624 tunnel->v4mapped = true; 1625 inet->inet_saddr = np->saddr.s6_addr32[3]; 1626 inet->inet_rcv_saddr = sk->sk_v6_rcv_saddr.s6_addr32[3]; 1627 inet->inet_daddr = sk->sk_v6_daddr.s6_addr32[3]; 1628 } else { 1629 tunnel->v4mapped = false; 1630 } 1631 } 1632 #endif 1633 1634 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ 1635 tunnel->encap = encap; 1636 if (encap == L2TP_ENCAPTYPE_UDP) { 1637 struct udp_tunnel_sock_cfg udp_cfg = { }; 1638 1639 udp_cfg.sk_user_data = tunnel; 1640 udp_cfg.encap_type = UDP_ENCAP_L2TPINUDP; 1641 udp_cfg.encap_rcv = l2tp_udp_encap_recv; 1642 udp_cfg.encap_destroy = l2tp_udp_encap_destroy; 1643 1644 setup_udp_tunnel_sock(net, sock, &udp_cfg); 1645 } else { 1646 sk->sk_user_data = tunnel; 1647 } 1648 1649 /* Hook on the tunnel socket destructor so that we can cleanup 1650 * if the tunnel socket goes away. 1651 */ 1652 tunnel->old_sk_destruct = sk->sk_destruct; 1653 sk->sk_destruct = &l2tp_tunnel_destruct; 1654 tunnel->sock = sk; 1655 tunnel->fd = fd; 1656 lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock"); 1657 1658 sk->sk_allocation = GFP_ATOMIC; 1659 1660 /* Init delete workqueue struct */ 1661 INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work); 1662 1663 /* Add tunnel to our list */ 1664 INIT_LIST_HEAD(&tunnel->list); 1665 atomic_inc(&l2tp_tunnel_count); 1666 1667 /* Bump the reference count. The tunnel context is deleted 1668 * only when this drops to zero. Must be done before list insertion 1669 */ 1670 refcount_set(&tunnel->ref_count, 1); 1671 spin_lock_bh(&pn->l2tp_tunnel_list_lock); 1672 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); 1673 spin_unlock_bh(&pn->l2tp_tunnel_list_lock); 1674 1675 err = 0; 1676 err: 1677 if (tunnelp) 1678 *tunnelp = tunnel; 1679 1680 /* If tunnel's socket was created by the kernel, it doesn't 1681 * have a file. 1682 */ 1683 if (sock && sock->file) 1684 sockfd_put(sock); 1685 1686 return err; 1687 } 1688 EXPORT_SYMBOL_GPL(l2tp_tunnel_create); 1689 1690 /* This function is used by the netlink TUNNEL_DELETE command. 1691 */ 1692 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) 1693 { 1694 l2tp_tunnel_inc_refcount(tunnel); 1695 if (false == queue_work(l2tp_wq, &tunnel->del_work)) { 1696 l2tp_tunnel_dec_refcount(tunnel); 1697 return 1; 1698 } 1699 return 0; 1700 } 1701 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); 1702 1703 /* Really kill the session. 1704 */ 1705 void l2tp_session_free(struct l2tp_session *session) 1706 { 1707 struct l2tp_tunnel *tunnel = session->tunnel; 1708 1709 BUG_ON(refcount_read(&session->ref_count) != 0); 1710 1711 if (tunnel) { 1712 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 1713 if (session->session_id != 0) 1714 atomic_dec(&l2tp_session_count); 1715 sock_put(tunnel->sock); 1716 session->tunnel = NULL; 1717 l2tp_tunnel_dec_refcount(tunnel); 1718 } 1719 1720 kfree(session); 1721 } 1722 EXPORT_SYMBOL_GPL(l2tp_session_free); 1723 1724 /* Remove an l2tp session from l2tp_core's hash lists. 1725 * Provides a tidyup interface for pseudowire code which can't just route all 1726 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close 1727 * callback. 1728 */ 1729 void __l2tp_session_unhash(struct l2tp_session *session) 1730 { 1731 struct l2tp_tunnel *tunnel = session->tunnel; 1732 1733 /* Remove the session from core hashes */ 1734 if (tunnel) { 1735 /* Remove from the per-tunnel hash */ 1736 write_lock_bh(&tunnel->hlist_lock); 1737 hlist_del_init(&session->hlist); 1738 write_unlock_bh(&tunnel->hlist_lock); 1739 1740 /* For L2TPv3 we have a per-net hash: remove from there, too */ 1741 if (tunnel->version != L2TP_HDR_VER_2) { 1742 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1743 spin_lock_bh(&pn->l2tp_session_hlist_lock); 1744 hlist_del_init_rcu(&session->global_hlist); 1745 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 1746 synchronize_rcu(); 1747 } 1748 } 1749 } 1750 EXPORT_SYMBOL_GPL(__l2tp_session_unhash); 1751 1752 /* This function is used by the netlink SESSION_DELETE command and by 1753 pseudowire modules. 1754 */ 1755 int l2tp_session_delete(struct l2tp_session *session) 1756 { 1757 if (session->ref) 1758 (*session->ref)(session); 1759 __l2tp_session_unhash(session); 1760 l2tp_session_queue_purge(session); 1761 if (session->session_close != NULL) 1762 (*session->session_close)(session); 1763 if (session->deref) 1764 (*session->deref)(session); 1765 l2tp_session_dec_refcount(session); 1766 return 0; 1767 } 1768 EXPORT_SYMBOL_GPL(l2tp_session_delete); 1769 1770 /* We come here whenever a session's send_seq, cookie_len or 1771 * l2specific_len parameters are set. 1772 */ 1773 void l2tp_session_set_header_len(struct l2tp_session *session, int version) 1774 { 1775 if (version == L2TP_HDR_VER_2) { 1776 session->hdr_len = 6; 1777 if (session->send_seq) 1778 session->hdr_len += 4; 1779 } else { 1780 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset; 1781 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP) 1782 session->hdr_len += 4; 1783 } 1784 1785 } 1786 EXPORT_SYMBOL_GPL(l2tp_session_set_header_len); 1787 1788 struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) 1789 { 1790 struct l2tp_session *session; 1791 int err; 1792 1793 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); 1794 if (session != NULL) { 1795 session->magic = L2TP_SESSION_MAGIC; 1796 session->tunnel = tunnel; 1797 1798 session->session_id = session_id; 1799 session->peer_session_id = peer_session_id; 1800 session->nr = 0; 1801 if (tunnel->version == L2TP_HDR_VER_2) 1802 session->nr_max = 0xffff; 1803 else 1804 session->nr_max = 0xffffff; 1805 session->nr_window_size = session->nr_max / 2; 1806 session->nr_oos_count_max = 4; 1807 1808 /* Use NR of first received packet */ 1809 session->reorder_skip = 1; 1810 1811 sprintf(&session->name[0], "sess %u/%u", 1812 tunnel->tunnel_id, session->session_id); 1813 1814 skb_queue_head_init(&session->reorder_q); 1815 1816 INIT_HLIST_NODE(&session->hlist); 1817 INIT_HLIST_NODE(&session->global_hlist); 1818 1819 /* Inherit debug options from tunnel */ 1820 session->debug = tunnel->debug; 1821 1822 if (cfg) { 1823 session->pwtype = cfg->pw_type; 1824 session->debug = cfg->debug; 1825 session->mtu = cfg->mtu; 1826 session->mru = cfg->mru; 1827 session->send_seq = cfg->send_seq; 1828 session->recv_seq = cfg->recv_seq; 1829 session->lns_mode = cfg->lns_mode; 1830 session->reorder_timeout = cfg->reorder_timeout; 1831 session->offset = cfg->offset; 1832 session->l2specific_type = cfg->l2specific_type; 1833 session->l2specific_len = cfg->l2specific_len; 1834 session->cookie_len = cfg->cookie_len; 1835 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); 1836 session->peer_cookie_len = cfg->peer_cookie_len; 1837 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); 1838 } 1839 1840 if (tunnel->version == L2TP_HDR_VER_2) 1841 session->build_header = l2tp_build_l2tpv2_header; 1842 else 1843 session->build_header = l2tp_build_l2tpv3_header; 1844 1845 l2tp_session_set_header_len(session, tunnel->version); 1846 1847 err = l2tp_session_add_to_tunnel(tunnel, session); 1848 if (err) { 1849 kfree(session); 1850 1851 return ERR_PTR(err); 1852 } 1853 1854 /* Bump the reference count. The session context is deleted 1855 * only when this drops to zero. 1856 */ 1857 refcount_set(&session->ref_count, 1); 1858 l2tp_tunnel_inc_refcount(tunnel); 1859 1860 /* Ensure tunnel socket isn't deleted */ 1861 sock_hold(tunnel->sock); 1862 1863 /* Ignore management session in session count value */ 1864 if (session->session_id != 0) 1865 atomic_inc(&l2tp_session_count); 1866 1867 return session; 1868 } 1869 1870 return ERR_PTR(-ENOMEM); 1871 } 1872 EXPORT_SYMBOL_GPL(l2tp_session_create); 1873 1874 /***************************************************************************** 1875 * Init and cleanup 1876 *****************************************************************************/ 1877 1878 static __net_init int l2tp_init_net(struct net *net) 1879 { 1880 struct l2tp_net *pn = net_generic(net, l2tp_net_id); 1881 int hash; 1882 1883 INIT_LIST_HEAD(&pn->l2tp_tunnel_list); 1884 spin_lock_init(&pn->l2tp_tunnel_list_lock); 1885 1886 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) 1887 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]); 1888 1889 spin_lock_init(&pn->l2tp_session_hlist_lock); 1890 1891 return 0; 1892 } 1893 1894 static __net_exit void l2tp_exit_net(struct net *net) 1895 { 1896 struct l2tp_net *pn = l2tp_pernet(net); 1897 struct l2tp_tunnel *tunnel = NULL; 1898 1899 rcu_read_lock_bh(); 1900 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 1901 (void)l2tp_tunnel_delete(tunnel); 1902 } 1903 rcu_read_unlock_bh(); 1904 1905 flush_workqueue(l2tp_wq); 1906 rcu_barrier(); 1907 } 1908 1909 static struct pernet_operations l2tp_net_ops = { 1910 .init = l2tp_init_net, 1911 .exit = l2tp_exit_net, 1912 .id = &l2tp_net_id, 1913 .size = sizeof(struct l2tp_net), 1914 }; 1915 1916 static 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 1934 out: 1935 return rc; 1936 } 1937 1938 static 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 1947 module_init(l2tp_init); 1948 module_exit(l2tp_exit); 1949 1950 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 1951 MODULE_DESCRIPTION("L2TP core"); 1952 MODULE_LICENSE("GPL"); 1953 MODULE_VERSION(L2TP_DRV_VERSION); 1954 1955