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_MAX 14
87
88 /* Default trace flags */
89 #define L2TP_DEFAULT_DEBUG_FLAGS 0
90
91 /* Private data stored for received packets in the skb.
92 */
93 struct l2tp_skb_cb {
94 u32 ns;
95 u16 has_seq;
96 u16 length;
97 unsigned long expires;
98 };
99
100 #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
101
102 static atomic_t l2tp_tunnel_count;
103 static atomic_t l2tp_session_count;
104 static struct workqueue_struct *l2tp_wq;
105
106 /* per-net private data for this module */
107 static unsigned int l2tp_net_id;
108 struct l2tp_net {
109 struct list_head l2tp_tunnel_list;
110 spinlock_t l2tp_tunnel_list_lock;
111 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
112 spinlock_t l2tp_session_hlist_lock;
113 };
114
115
116 static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk)
117 {
118 return sk->sk_user_data;
119 }
120
121 static inline struct l2tp_net *l2tp_pernet(const struct net *net)
122 {
123 BUG_ON(!net);
124
125 return net_generic(net, l2tp_net_id);
126 }
127
128 /* Session hash global list for L2TPv3.
129 * The session_id SHOULD be random according to RFC3931, but several
130 * L2TP implementations use incrementing session_ids. So we do a real
131 * hash on the session_id, rather than a simple bitmask.
132 */
133 static inline struct hlist_head *
134 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
135 {
136 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
137
138 }
139
140 /* Lookup the tunnel socket, possibly involving the fs code if the socket is
141 * owned by userspace. A struct sock returned from this function must be
142 * released using l2tp_tunnel_sock_put once you're done with it.
143 */
144 static struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel)
145 {
146 int err = 0;
147 struct socket *sock = NULL;
148 struct sock *sk = NULL;
149
150 if (!tunnel)
151 goto out;
152
153 if (tunnel->fd >= 0) {
154 /* Socket is owned by userspace, who might be in the process
155 * of closing it. Look the socket up using the fd to ensure
156 * consistency.
157 */
158 sock = sockfd_lookup(tunnel->fd, &err);
159 if (sock)
160 sk = sock->sk;
161 } else {
162 /* Socket is owned by kernelspace */
163 sk = tunnel->sock;
164 sock_hold(sk);
165 }
166
167 out:
168 return sk;
169 }
170
171 /* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */
172 static void l2tp_tunnel_sock_put(struct sock *sk)
173 {
174 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
175 if (tunnel) {
176 if (tunnel->fd >= 0) {
177 /* Socket is owned by userspace */
178 sockfd_put(sk->sk_socket);
179 }
180 sock_put(sk);
181 }
182 sock_put(sk);
183 }
184
185 /* Session hash list.
186 * The session_id SHOULD be random according to RFC2661, but several
187 * L2TP implementations (Cisco and Microsoft) use incrementing
188 * session_ids. So we do a real hash on the session_id, rather than a
189 * simple bitmask.
190 */
191 static inline struct hlist_head *
192 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
193 {
194 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
195 }
196
197 /* Lookup a tunnel. A new reference is held on the returned tunnel. */
198 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id)
199 {
200 const struct l2tp_net *pn = l2tp_pernet(net);
201 struct l2tp_tunnel *tunnel;
202
203 rcu_read_lock_bh();
204 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
205 if (tunnel->tunnel_id == tunnel_id) {
206 l2tp_tunnel_inc_refcount(tunnel);
207 rcu_read_unlock_bh();
208
209 return tunnel;
210 }
211 }
212 rcu_read_unlock_bh();
213
214 return NULL;
215 }
216 EXPORT_SYMBOL_GPL(l2tp_tunnel_get);
217
218 /* Lookup a session. A new reference is held on the returned session.
219 * Optionally calls session->ref() too if do_ref is true.
220 */
221 struct l2tp_session *l2tp_session_get(const struct net *net,
222 struct l2tp_tunnel *tunnel,
223 u32 session_id, bool do_ref)
224 {
225 struct hlist_head *session_list;
226 struct l2tp_session *session;
227
228 if (!tunnel) {
229 struct l2tp_net *pn = l2tp_pernet(net);
230
231 session_list = l2tp_session_id_hash_2(pn, session_id);
232
233 rcu_read_lock_bh();
234 hlist_for_each_entry_rcu(session, session_list, global_hlist) {
235 if (session->session_id == session_id) {
236 l2tp_session_inc_refcount(session);
237 if (do_ref && session->ref)
238 session->ref(session);
239 rcu_read_unlock_bh();
240
241 return session;
242 }
243 }
244 rcu_read_unlock_bh();
245
246 return NULL;
247 }
248
249 session_list = l2tp_session_id_hash(tunnel, session_id);
250 read_lock_bh(&tunnel->hlist_lock);
251 hlist_for_each_entry(session, session_list, hlist) {
252 if (session->session_id == session_id) {
253 l2tp_session_inc_refcount(session);
254 if (do_ref && session->ref)
255 session->ref(session);
256 read_unlock_bh(&tunnel->hlist_lock);
257
258 return session;
259 }
260 }
261 read_unlock_bh(&tunnel->hlist_lock);
262
263 return NULL;
264 }
265 EXPORT_SYMBOL_GPL(l2tp_session_get);
266
267 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
268 bool do_ref)
269 {
270 int hash;
271 struct l2tp_session *session;
272 int count = 0;
273
274 read_lock_bh(&tunnel->hlist_lock);
275 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
276 hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) {
277 if (++count > nth) {
278 l2tp_session_inc_refcount(session);
279 if (do_ref && session->ref)
280 session->ref(session);
281 read_unlock_bh(&tunnel->hlist_lock);
282 return session;
283 }
284 }
285 }
286
287 read_unlock_bh(&tunnel->hlist_lock);
288
289 return NULL;
290 }
291 EXPORT_SYMBOL_GPL(l2tp_session_get_nth);
292
293 /* Lookup a session by interface name.
294 * This is very inefficient but is only used by management interfaces.
295 */
296 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
297 const char *ifname,
298 bool do_ref)
299 {
300 struct l2tp_net *pn = l2tp_pernet(net);
301 int hash;
302 struct l2tp_session *session;
303
304 rcu_read_lock_bh();
305 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
306 hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) {
307 if (!strcmp(session->ifname, ifname)) {
308 l2tp_session_inc_refcount(session);
309 if (do_ref && session->ref)
310 session->ref(session);
311 rcu_read_unlock_bh();
312
313 return session;
314 }
315 }
316 }
317
318 rcu_read_unlock_bh();
319
320 return NULL;
321 }
322 EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname);
323
324 int l2tp_session_register(struct l2tp_session *session,
325 struct l2tp_tunnel *tunnel)
326 {
327 struct l2tp_session *session_walk;
328 struct hlist_head *g_head;
329 struct hlist_head *head;
330 struct l2tp_net *pn;
331 int err;
332
333 head = l2tp_session_id_hash(tunnel, session->session_id);
334
335 write_lock_bh(&tunnel->hlist_lock);
336 if (!tunnel->acpt_newsess) {
337 err = -ENODEV;
338 goto err_tlock;
339 }
340
341 hlist_for_each_entry(session_walk, head, hlist)
342 if (session_walk->session_id == session->session_id) {
343 err = -EEXIST;
344 goto err_tlock;
345 }
346
347 if (tunnel->version == L2TP_HDR_VER_3) {
348 pn = l2tp_pernet(tunnel->l2tp_net);
349 g_head = l2tp_session_id_hash_2(l2tp_pernet(tunnel->l2tp_net),
350 session->session_id);
351
352 spin_lock_bh(&pn->l2tp_session_hlist_lock);
353
354 /* IP encap expects session IDs to be globally unique, while
355 * UDP encap doesn't.
356 */
357 hlist_for_each_entry(session_walk, g_head, global_hlist)
358 if (session_walk->session_id == session->session_id &&
359 (session_walk->tunnel->encap == L2TP_ENCAPTYPE_IP ||
360 tunnel->encap == L2TP_ENCAPTYPE_IP)) {
361 err = -EEXIST;
362 goto err_tlock_pnlock;
363 }
364
365 l2tp_tunnel_inc_refcount(tunnel);
366 sock_hold(tunnel->sock);
367 hlist_add_head_rcu(&session->global_hlist, g_head);
368
369 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
370 } else {
371 l2tp_tunnel_inc_refcount(tunnel);
372 sock_hold(tunnel->sock);
373 }
374
375 hlist_add_head(&session->hlist, head);
376 write_unlock_bh(&tunnel->hlist_lock);
377
378 /* Ignore management session in session count value */
379 if (session->session_id != 0)
380 atomic_inc(&l2tp_session_count);
381
382 return 0;
383
384 err_tlock_pnlock:
385 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
386 err_tlock:
387 write_unlock_bh(&tunnel->hlist_lock);
388
389 return err;
390 }
391 EXPORT_SYMBOL_GPL(l2tp_session_register);
392
393 /* Lookup a tunnel by id
394 */
395 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id)
396 {
397 struct l2tp_tunnel *tunnel;
398 struct l2tp_net *pn = l2tp_pernet(net);
399
400 rcu_read_lock_bh();
401 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
402 if (tunnel->tunnel_id == tunnel_id) {
403 rcu_read_unlock_bh();
404 return tunnel;
405 }
406 }
407 rcu_read_unlock_bh();
408
409 return NULL;
410 }
411 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
412
413 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth)
414 {
415 struct l2tp_net *pn = l2tp_pernet(net);
416 struct l2tp_tunnel *tunnel;
417 int count = 0;
418
419 rcu_read_lock_bh();
420 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
421 if (++count > nth) {
422 rcu_read_unlock_bh();
423 return tunnel;
424 }
425 }
426
427 rcu_read_unlock_bh();
428
429 return NULL;
430 }
431 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
432
433 /*****************************************************************************
434 * Receive data handling
435 *****************************************************************************/
436
437 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
438 * number.
439 */
440 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
441 {
442 struct sk_buff *skbp;
443 struct sk_buff *tmp;
444 u32 ns = L2TP_SKB_CB(skb)->ns;
445
446 spin_lock_bh(&session->reorder_q.lock);
447 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
448 if (L2TP_SKB_CB(skbp)->ns > ns) {
449 __skb_queue_before(&session->reorder_q, skbp, skb);
450 l2tp_dbg(session, L2TP_MSG_SEQ,
451 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
452 session->name, ns, L2TP_SKB_CB(skbp)->ns,
453 skb_queue_len(&session->reorder_q));
454 atomic_long_inc(&session->stats.rx_oos_packets);
455 goto out;
456 }
457 }
458
459 __skb_queue_tail(&session->reorder_q, skb);
460
461 out:
462 spin_unlock_bh(&session->reorder_q.lock);
463 }
464
465 /* Dequeue a single skb.
466 */
467 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
468 {
469 struct l2tp_tunnel *tunnel = session->tunnel;
470 int length = L2TP_SKB_CB(skb)->length;
471
472 /* We're about to requeue the skb, so return resources
473 * to its current owner (a socket receive buffer).
474 */
475 skb_orphan(skb);
476
477 atomic_long_inc(&tunnel->stats.rx_packets);
478 atomic_long_add(length, &tunnel->stats.rx_bytes);
479 atomic_long_inc(&session->stats.rx_packets);
480 atomic_long_add(length, &session->stats.rx_bytes);
481
482 if (L2TP_SKB_CB(skb)->has_seq) {
483 /* Bump our Nr */
484 session->nr++;
485 session->nr &= session->nr_max;
486
487 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
488 session->name, session->nr);
489 }
490
491 /* call private receive handler */
492 if (session->recv_skb != NULL)
493 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
494 else
495 kfree_skb(skb);
496
497 if (session->deref)
498 (*session->deref)(session);
499 }
500
501 /* Dequeue skbs from the session's reorder_q, subject to packet order.
502 * Skbs that have been in the queue for too long are simply discarded.
503 */
504 static void l2tp_recv_dequeue(struct l2tp_session *session)
505 {
506 struct sk_buff *skb;
507 struct sk_buff *tmp;
508
509 /* If the pkt at the head of the queue has the nr that we
510 * expect to send up next, dequeue it and any other
511 * in-sequence packets behind it.
512 */
513 start:
514 spin_lock_bh(&session->reorder_q.lock);
515 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
516 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
517 atomic_long_inc(&session->stats.rx_seq_discards);
518 atomic_long_inc(&session->stats.rx_errors);
519 l2tp_dbg(session, L2TP_MSG_SEQ,
520 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
521 session->name, L2TP_SKB_CB(skb)->ns,
522 L2TP_SKB_CB(skb)->length, session->nr,
523 skb_queue_len(&session->reorder_q));
524 session->reorder_skip = 1;
525 __skb_unlink(skb, &session->reorder_q);
526 kfree_skb(skb);
527 if (session->deref)
528 (*session->deref)(session);
529 continue;
530 }
531
532 if (L2TP_SKB_CB(skb)->has_seq) {
533 if (session->reorder_skip) {
534 l2tp_dbg(session, L2TP_MSG_SEQ,
535 "%s: advancing nr to next pkt: %u -> %u",
536 session->name, session->nr,
537 L2TP_SKB_CB(skb)->ns);
538 session->reorder_skip = 0;
539 session->nr = L2TP_SKB_CB(skb)->ns;
540 }
541 if (L2TP_SKB_CB(skb)->ns != session->nr) {
542 l2tp_dbg(session, L2TP_MSG_SEQ,
543 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
544 session->name, L2TP_SKB_CB(skb)->ns,
545 L2TP_SKB_CB(skb)->length, session->nr,
546 skb_queue_len(&session->reorder_q));
547 goto out;
548 }
549 }
550 __skb_unlink(skb, &session->reorder_q);
551
552 /* Process the skb. We release the queue lock while we
553 * do so to let other contexts process the queue.
554 */
555 spin_unlock_bh(&session->reorder_q.lock);
556 l2tp_recv_dequeue_skb(session, skb);
557 goto start;
558 }
559
560 out:
561 spin_unlock_bh(&session->reorder_q.lock);
562 }
563
564 static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
565 {
566 u32 nws;
567
568 if (nr >= session->nr)
569 nws = nr - session->nr;
570 else
571 nws = (session->nr_max + 1) - (session->nr - nr);
572
573 return nws < session->nr_window_size;
574 }
575
576 /* If packet has sequence numbers, queue it if acceptable. Returns 0 if
577 * acceptable, else non-zero.
578 */
579 static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb)
580 {
581 if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) {
582 /* Packet sequence number is outside allowed window.
583 * Discard it.
584 */
585 l2tp_dbg(session, L2TP_MSG_SEQ,
586 "%s: pkt %u len %d discarded, outside window, nr=%u\n",
587 session->name, L2TP_SKB_CB(skb)->ns,
588 L2TP_SKB_CB(skb)->length, session->nr);
589 goto discard;
590 }
591
592 if (session->reorder_timeout != 0) {
593 /* Packet reordering enabled. Add skb to session's
594 * reorder queue, in order of ns.
595 */
596 l2tp_recv_queue_skb(session, skb);
597 goto out;
598 }
599
600 /* Packet reordering disabled. Discard out-of-sequence packets, while
601 * tracking the number if in-sequence packets after the first OOS packet
602 * is seen. After nr_oos_count_max in-sequence packets, reset the
603 * sequence number to re-enable packet reception.
604 */
605 if (L2TP_SKB_CB(skb)->ns == session->nr) {
606 skb_queue_tail(&session->reorder_q, skb);
607 } else {
608 u32 nr_oos = L2TP_SKB_CB(skb)->ns;
609 u32 nr_next = (session->nr_oos + 1) & session->nr_max;
610
611 if (nr_oos == nr_next)
612 session->nr_oos_count++;
613 else
614 session->nr_oos_count = 0;
615
616 session->nr_oos = nr_oos;
617 if (session->nr_oos_count > session->nr_oos_count_max) {
618 session->reorder_skip = 1;
619 l2tp_dbg(session, L2TP_MSG_SEQ,
620 "%s: %d oos packets received. Resetting sequence numbers\n",
621 session->name, session->nr_oos_count);
622 }
623 if (!session->reorder_skip) {
624 atomic_long_inc(&session->stats.rx_seq_discards);
625 l2tp_dbg(session, L2TP_MSG_SEQ,
626 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
627 session->name, L2TP_SKB_CB(skb)->ns,
628 L2TP_SKB_CB(skb)->length, session->nr,
629 skb_queue_len(&session->reorder_q));
630 goto discard;
631 }
632 skb_queue_tail(&session->reorder_q, skb);
633 }
634
635 out:
636 return 0;
637
638 discard:
639 return 1;
640 }
641
642 /* Do receive processing of L2TP data frames. We handle both L2TPv2
643 * and L2TPv3 data frames here.
644 *
645 * L2TPv2 Data Message Header
646 *
647 * 0 1 2 3
648 * 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
649 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
650 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
651 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
652 * | Tunnel ID | Session ID |
653 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
654 * | Ns (opt) | Nr (opt) |
655 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
656 * | Offset Size (opt) | Offset pad... (opt)
657 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
658 *
659 * Data frames are marked by T=0. All other fields are the same as
660 * those in L2TP control frames.
661 *
662 * L2TPv3 Data Message Header
663 *
664 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
665 * | L2TP Session Header |
666 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
667 * | L2-Specific Sublayer |
668 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
669 * | Tunnel Payload ...
670 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
671 *
672 * L2TPv3 Session Header Over IP
673 *
674 * 0 1 2 3
675 * 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
676 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
677 * | Session ID |
678 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
679 * | Cookie (optional, maximum 64 bits)...
680 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
681 * |
682 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
683 *
684 * L2TPv3 L2-Specific Sublayer Format
685 *
686 * 0 1 2 3
687 * 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
688 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
689 * |x|S|x|x|x|x|x|x| Sequence Number |
690 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
691 *
692 * Cookie value, sublayer format and offset (pad) are negotiated with
693 * the peer when the session is set up. Unlike L2TPv2, we do not need
694 * to parse the packet header to determine if optional fields are
695 * present.
696 *
697 * Caller must already have parsed the frame and determined that it is
698 * a data (not control) frame before coming here. Fields up to the
699 * session-id have already been parsed and ptr points to the data
700 * after the session-id.
701 *
702 * session->ref() must have been called prior to l2tp_recv_common().
703 * session->deref() will be called automatically after skb is processed.
704 */
705 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
706 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
707 int length, int (*payload_hook)(struct sk_buff *skb))
708 {
709 struct l2tp_tunnel *tunnel = session->tunnel;
710 int offset;
711 u32 ns, nr;
712
713 /* Parse and check optional cookie */
714 if (session->peer_cookie_len > 0) {
715 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
716 l2tp_info(tunnel, L2TP_MSG_DATA,
717 "%s: cookie mismatch (%u/%u). Discarding.\n",
718 tunnel->name, tunnel->tunnel_id,
719 session->session_id);
720 atomic_long_inc(&session->stats.rx_cookie_discards);
721 goto discard;
722 }
723 ptr += session->peer_cookie_len;
724 }
725
726 /* Handle the optional sequence numbers. Sequence numbers are
727 * in different places for L2TPv2 and L2TPv3.
728 *
729 * If we are the LAC, enable/disable sequence numbers under
730 * the control of the LNS. If no sequence numbers present but
731 * we were expecting them, discard frame.
732 */
733 ns = nr = 0;
734 L2TP_SKB_CB(skb)->has_seq = 0;
735 if (tunnel->version == L2TP_HDR_VER_2) {
736 if (hdrflags & L2TP_HDRFLAG_S) {
737 ns = ntohs(*(__be16 *) ptr);
738 ptr += 2;
739 nr = ntohs(*(__be16 *) ptr);
740 ptr += 2;
741
742 /* Store L2TP info in the skb */
743 L2TP_SKB_CB(skb)->ns = ns;
744 L2TP_SKB_CB(skb)->has_seq = 1;
745
746 l2tp_dbg(session, L2TP_MSG_SEQ,
747 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
748 session->name, ns, nr, session->nr);
749 }
750 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
751 u32 l2h = ntohl(*(__be32 *) ptr);
752
753 if (l2h & 0x40000000) {
754 ns = l2h & 0x00ffffff;
755
756 /* Store L2TP info in the skb */
757 L2TP_SKB_CB(skb)->ns = ns;
758 L2TP_SKB_CB(skb)->has_seq = 1;
759
760 l2tp_dbg(session, L2TP_MSG_SEQ,
761 "%s: recv data ns=%u, session nr=%u\n",
762 session->name, ns, session->nr);
763 }
764 ptr += 4;
765 }
766
767 if (L2TP_SKB_CB(skb)->has_seq) {
768 /* Received a packet with sequence numbers. If we're the LNS,
769 * check if we sre sending sequence numbers and if not,
770 * configure it so.
771 */
772 if ((!session->lns_mode) && (!session->send_seq)) {
773 l2tp_info(session, L2TP_MSG_SEQ,
774 "%s: requested to enable seq numbers by LNS\n",
775 session->name);
776 session->send_seq = -1;
777 l2tp_session_set_header_len(session, tunnel->version);
778 }
779 } else {
780 /* No sequence numbers.
781 * If user has configured mandatory sequence numbers, discard.
782 */
783 if (session->recv_seq) {
784 l2tp_warn(session, L2TP_MSG_SEQ,
785 "%s: recv data has no seq numbers when required. Discarding.\n",
786 session->name);
787 atomic_long_inc(&session->stats.rx_seq_discards);
788 goto discard;
789 }
790
791 /* If we're the LAC and we're sending sequence numbers, the
792 * LNS has requested that we no longer send sequence numbers.
793 * If we're the LNS and we're sending sequence numbers, the
794 * LAC is broken. Discard the frame.
795 */
796 if ((!session->lns_mode) && (session->send_seq)) {
797 l2tp_info(session, L2TP_MSG_SEQ,
798 "%s: requested to disable seq numbers by LNS\n",
799 session->name);
800 session->send_seq = 0;
801 l2tp_session_set_header_len(session, tunnel->version);
802 } else if (session->send_seq) {
803 l2tp_warn(session, L2TP_MSG_SEQ,
804 "%s: recv data has no seq numbers when required. Discarding.\n",
805 session->name);
806 atomic_long_inc(&session->stats.rx_seq_discards);
807 goto discard;
808 }
809 }
810
811 /* Session data offset is handled differently for L2TPv2 and
812 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
813 * the header. For L2TPv3, the offset is negotiated using AVPs
814 * in the session setup control protocol.
815 */
816 if (tunnel->version == L2TP_HDR_VER_2) {
817 /* If offset bit set, skip it. */
818 if (hdrflags & L2TP_HDRFLAG_O) {
819 offset = ntohs(*(__be16 *)ptr);
820 ptr += 2 + offset;
821 }
822 } else
823 ptr += session->offset;
824
825 offset = ptr - optr;
826 if (!pskb_may_pull(skb, offset))
827 goto discard;
828
829 __skb_pull(skb, offset);
830
831 /* If caller wants to process the payload before we queue the
832 * packet, do so now.
833 */
834 if (payload_hook)
835 if ((*payload_hook)(skb))
836 goto discard;
837
838 /* Prepare skb for adding to the session's reorder_q. Hold
839 * packets for max reorder_timeout or 1 second if not
840 * reordering.
841 */
842 L2TP_SKB_CB(skb)->length = length;
843 L2TP_SKB_CB(skb)->expires = jiffies +
844 (session->reorder_timeout ? session->reorder_timeout : HZ);
845
846 /* Add packet to the session's receive queue. Reordering is done here, if
847 * enabled. Saved L2TP protocol info is stored in skb->sb[].
848 */
849 if (L2TP_SKB_CB(skb)->has_seq) {
850 if (l2tp_recv_data_seq(session, skb))
851 goto discard;
852 } else {
853 /* No sequence numbers. Add the skb to the tail of the
854 * reorder queue. This ensures that it will be
855 * delivered after all previous sequenced skbs.
856 */
857 skb_queue_tail(&session->reorder_q, skb);
858 }
859
860 /* Try to dequeue as many skbs from reorder_q as we can. */
861 l2tp_recv_dequeue(session);
862
863 return;
864
865 discard:
866 atomic_long_inc(&session->stats.rx_errors);
867 kfree_skb(skb);
868
869 if (session->deref)
870 (*session->deref)(session);
871 }
872 EXPORT_SYMBOL(l2tp_recv_common);
873
874 /* Drop skbs from the session's reorder_q
875 */
876 int l2tp_session_queue_purge(struct l2tp_session *session)
877 {
878 struct sk_buff *skb = NULL;
879 BUG_ON(!session);
880 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
881 while ((skb = skb_dequeue(&session->reorder_q))) {
882 atomic_long_inc(&session->stats.rx_errors);
883 kfree_skb(skb);
884 if (session->deref)
885 (*session->deref)(session);
886 }
887 return 0;
888 }
889 EXPORT_SYMBOL_GPL(l2tp_session_queue_purge);
890
891 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
892 * here. The skb is not on a list when we get here.
893 * Returns 0 if the packet was a data packet and was successfully passed on.
894 * Returns 1 if the packet was not a good data packet and could not be
895 * forwarded. All such packets are passed up to userspace to deal with.
896 */
897 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
898 int (*payload_hook)(struct sk_buff *skb))
899 {
900 struct l2tp_session *session = NULL;
901 unsigned char *ptr, *optr;
902 u16 hdrflags;
903 u32 tunnel_id, session_id;
904 u16 version;
905 int length;
906
907 /* UDP has verifed checksum */
908
909 /* UDP always verifies the packet length. */
910 __skb_pull(skb, sizeof(struct udphdr));
911
912 /* Short packet? */
913 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_MAX)) {
914 l2tp_info(tunnel, L2TP_MSG_DATA,
915 "%s: recv short packet (len=%d)\n",
916 tunnel->name, skb->len);
917 goto error;
918 }
919
920 /* Trace packet contents, if enabled */
921 if (tunnel->debug & L2TP_MSG_DATA) {
922 length = min(32u, skb->len);
923 if (!pskb_may_pull(skb, length))
924 goto error;
925
926 pr_debug("%s: recv\n", tunnel->name);
927 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
928 }
929
930 /* Point to L2TP header */
931 optr = ptr = skb->data;
932
933 /* Get L2TP header flags */
934 hdrflags = ntohs(*(__be16 *) ptr);
935
936 /* Check protocol version */
937 version = hdrflags & L2TP_HDR_VER_MASK;
938 if (version != tunnel->version) {
939 l2tp_info(tunnel, L2TP_MSG_DATA,
940 "%s: recv protocol version mismatch: got %d expected %d\n",
941 tunnel->name, version, tunnel->version);
942 goto error;
943 }
944
945 /* Get length of L2TP packet */
946 length = skb->len;
947
948 /* If type is control packet, it is handled by userspace. */
949 if (hdrflags & L2TP_HDRFLAG_T) {
950 l2tp_dbg(tunnel, L2TP_MSG_DATA,
951 "%s: recv control packet, len=%d\n",
952 tunnel->name, length);
953 goto error;
954 }
955
956 /* Skip flags */
957 ptr += 2;
958
959 if (tunnel->version == L2TP_HDR_VER_2) {
960 /* If length is present, skip it */
961 if (hdrflags & L2TP_HDRFLAG_L)
962 ptr += 2;
963
964 /* Extract tunnel and session ID */
965 tunnel_id = ntohs(*(__be16 *) ptr);
966 ptr += 2;
967 session_id = ntohs(*(__be16 *) ptr);
968 ptr += 2;
969 } else {
970 ptr += 2; /* skip reserved bits */
971 tunnel_id = tunnel->tunnel_id;
972 session_id = ntohl(*(__be32 *) ptr);
973 ptr += 4;
974 }
975
976 /* Find the session context */
977 session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id, true);
978 if (!session || !session->recv_skb) {
979 if (session) {
980 if (session->deref)
981 session->deref(session);
982 l2tp_session_dec_refcount(session);
983 }
984
985 /* Not found? Pass to userspace to deal with */
986 l2tp_info(tunnel, L2TP_MSG_DATA,
987 "%s: no session found (%u/%u). Passing up.\n",
988 tunnel->name, tunnel_id, session_id);
989 goto error;
990 }
991
992 if (tunnel->version == L2TP_HDR_VER_3 &&
993 l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) {
994 l2tp_session_dec_refcount(session);
995 goto error;
996 }
997
998 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
999 l2tp_session_dec_refcount(session);
1000
1001 return 0;
1002
1003 error:
1004 /* Put UDP header back */
1005 __skb_push(skb, sizeof(struct udphdr));
1006
1007 return 1;
1008 }
1009
1010 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
1011 * Return codes:
1012 * 0 : success.
1013 * <0: error
1014 * >0: skb should be passed up to userspace as UDP.
1015 */
1016 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
1017 {
1018 struct l2tp_tunnel *tunnel;
1019
1020 tunnel = l2tp_sock_to_tunnel(sk);
1021 if (tunnel == NULL)
1022 goto pass_up;
1023
1024 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
1025 tunnel->name, skb->len);
1026
1027 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
1028 goto pass_up_put;
1029
1030 sock_put(sk);
1031 return 0;
1032
1033 pass_up_put:
1034 sock_put(sk);
1035 pass_up:
1036 return 1;
1037 }
1038 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
1039
1040 /************************************************************************
1041 * Transmit handling
1042 ***********************************************************************/
1043
1044 /* Build an L2TP header for the session into the buffer provided.
1045 */
1046 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
1047 {
1048 struct l2tp_tunnel *tunnel = session->tunnel;
1049 __be16 *bufp = buf;
1050 __be16 *optr = buf;
1051 u16 flags = L2TP_HDR_VER_2;
1052 u32 tunnel_id = tunnel->peer_tunnel_id;
1053 u32 session_id = session->peer_session_id;
1054
1055 if (session->send_seq)
1056 flags |= L2TP_HDRFLAG_S;
1057
1058 /* Setup L2TP header. */
1059 *bufp++ = htons(flags);
1060 *bufp++ = htons(tunnel_id);
1061 *bufp++ = htons(session_id);
1062 if (session->send_seq) {
1063 *bufp++ = htons(session->ns);
1064 *bufp++ = 0;
1065 session->ns++;
1066 session->ns &= 0xffff;
1067 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
1068 session->name, session->ns);
1069 }
1070
1071 return bufp - optr;
1072 }
1073
1074 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
1075 {
1076 struct l2tp_tunnel *tunnel = session->tunnel;
1077 char *bufp = buf;
1078 char *optr = bufp;
1079
1080 /* Setup L2TP header. The header differs slightly for UDP and
1081 * IP encapsulations. For UDP, there is 4 bytes of flags.
1082 */
1083 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1084 u16 flags = L2TP_HDR_VER_3;
1085 *((__be16 *) bufp) = htons(flags);
1086 bufp += 2;
1087 *((__be16 *) bufp) = 0;
1088 bufp += 2;
1089 }
1090
1091 *((__be32 *) bufp) = htonl(session->peer_session_id);
1092 bufp += 4;
1093 if (session->cookie_len) {
1094 memcpy(bufp, &session->cookie[0], session->cookie_len);
1095 bufp += session->cookie_len;
1096 }
1097 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
1098 u32 l2h = 0;
1099
1100 if (session->send_seq) {
1101 l2h = 0x40000000 | session->ns;
1102 session->ns++;
1103 session->ns &= 0xffffff;
1104 l2tp_dbg(session, L2TP_MSG_SEQ,
1105 "%s: updated ns to %u\n",
1106 session->name, session->ns);
1107 }
1108
1109 *((__be32 *)bufp) = htonl(l2h);
1110 bufp += 4;
1111 }
1112 if (session->offset)
1113 bufp += session->offset;
1114
1115 return bufp - optr;
1116 }
1117
1118 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1119 struct flowi *fl, size_t data_len)
1120 {
1121 struct l2tp_tunnel *tunnel = session->tunnel;
1122 unsigned int len = skb->len;
1123 int error;
1124
1125 /* Debug */
1126 if (session->send_seq)
1127 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes, ns=%u\n",
1128 session->name, data_len, session->ns - 1);
1129 else
1130 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes\n",
1131 session->name, data_len);
1132
1133 if (session->debug & L2TP_MSG_DATA) {
1134 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1135 unsigned char *datap = skb->data + uhlen;
1136
1137 pr_debug("%s: xmit\n", session->name);
1138 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
1139 datap, min_t(size_t, 32, len - uhlen));
1140 }
1141
1142 /* Queue the packet to IP for output */
1143 skb->ignore_df = 1;
1144 skb_dst_drop(skb);
1145 #if IS_ENABLED(CONFIG_IPV6)
1146 if (tunnel->sock->sk_family == PF_INET6 && !tunnel->v4mapped)
1147 error = inet6_csk_xmit(tunnel->sock, skb, NULL);
1148 else
1149 #endif
1150 error = ip_queue_xmit(tunnel->sock, skb, fl);
1151
1152 /* Update stats */
1153 if (error >= 0) {
1154 atomic_long_inc(&tunnel->stats.tx_packets);
1155 atomic_long_add(len, &tunnel->stats.tx_bytes);
1156 atomic_long_inc(&session->stats.tx_packets);
1157 atomic_long_add(len, &session->stats.tx_bytes);
1158 } else {
1159 atomic_long_inc(&tunnel->stats.tx_errors);
1160 atomic_long_inc(&session->stats.tx_errors);
1161 }
1162
1163 return 0;
1164 }
1165
1166 /* If caller requires the skb to have a ppp header, the header must be
1167 * inserted in the skb data before calling this function.
1168 */
1169 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1170 {
1171 int data_len = skb->len;
1172 struct l2tp_tunnel *tunnel = session->tunnel;
1173 struct sock *sk = tunnel->sock;
1174 struct flowi *fl;
1175 struct udphdr *uh;
1176 struct inet_sock *inet;
1177 int headroom;
1178 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1179 int udp_len;
1180 int ret = NET_XMIT_SUCCESS;
1181
1182 /* Check that there's enough headroom in the skb to insert IP,
1183 * UDP and L2TP headers. If not enough, expand it to
1184 * make room. Adjust truesize.
1185 */
1186 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1187 uhlen + hdr_len;
1188 if (skb_cow_head(skb, headroom)) {
1189 kfree_skb(skb);
1190 return NET_XMIT_DROP;
1191 }
1192
1193 /* Setup L2TP header */
1194 session->build_header(session, __skb_push(skb, hdr_len));
1195
1196 /* Reset skb netfilter state */
1197 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1198 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1199 IPSKB_REROUTED);
1200 nf_reset(skb);
1201
1202 bh_lock_sock(sk);
1203 if (sock_owned_by_user(sk)) {
1204 kfree_skb(skb);
1205 ret = NET_XMIT_DROP;
1206 goto out_unlock;
1207 }
1208
1209 inet = inet_sk(sk);
1210 fl = &inet->cork.fl;
1211 switch (tunnel->encap) {
1212 case L2TP_ENCAPTYPE_UDP:
1213 /* Setup UDP header */
1214 __skb_push(skb, sizeof(*uh));
1215 skb_reset_transport_header(skb);
1216 uh = udp_hdr(skb);
1217 uh->source = inet->inet_sport;
1218 uh->dest = inet->inet_dport;
1219 udp_len = uhlen + hdr_len + data_len;
1220 uh->len = htons(udp_len);
1221
1222 /* Calculate UDP checksum if configured to do so */
1223 #if IS_ENABLED(CONFIG_IPV6)
1224 if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
1225 udp6_set_csum(udp_get_no_check6_tx(sk),
1226 skb, &inet6_sk(sk)->saddr,
1227 &sk->sk_v6_daddr, udp_len);
1228 else
1229 #endif
1230 udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr,
1231 inet->inet_daddr, udp_len);
1232 break;
1233
1234 case L2TP_ENCAPTYPE_IP:
1235 break;
1236 }
1237
1238 l2tp_xmit_core(session, skb, fl, data_len);
1239 out_unlock:
1240 bh_unlock_sock(sk);
1241
1242 return ret;
1243 }
1244 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1245
1246 /*****************************************************************************
1247 * Tinnel and session create/destroy.
1248 *****************************************************************************/
1249
1250 /* Tunnel socket destruct hook.
1251 * The tunnel context is deleted only when all session sockets have been
1252 * closed.
1253 */
1254 static void l2tp_tunnel_destruct(struct sock *sk)
1255 {
1256 struct l2tp_tunnel *tunnel = l2tp_tunnel(sk);
1257 struct l2tp_net *pn;
1258
1259 if (tunnel == NULL)
1260 goto end;
1261
1262 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
1263
1264
1265 /* Disable udp encapsulation */
1266 switch (tunnel->encap) {
1267 case L2TP_ENCAPTYPE_UDP:
1268 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1269 (udp_sk(sk))->encap_type = 0;
1270 (udp_sk(sk))->encap_rcv = NULL;
1271 (udp_sk(sk))->encap_destroy = NULL;
1272 break;
1273 case L2TP_ENCAPTYPE_IP:
1274 break;
1275 }
1276
1277 /* Remove hooks into tunnel socket */
1278 sk->sk_destruct = tunnel->old_sk_destruct;
1279 sk->sk_user_data = NULL;
1280
1281 /* Remove the tunnel struct from the tunnel list */
1282 pn = l2tp_pernet(tunnel->l2tp_net);
1283 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1284 list_del_rcu(&tunnel->list);
1285 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1286 atomic_dec(&l2tp_tunnel_count);
1287
1288 l2tp_tunnel_closeall(tunnel);
1289
1290 tunnel->sock = NULL;
1291 l2tp_tunnel_dec_refcount(tunnel);
1292
1293 /* Call the original destructor */
1294 if (sk->sk_destruct)
1295 (*sk->sk_destruct)(sk);
1296 end:
1297 return;
1298 }
1299
1300 /* When the tunnel is closed, all the attached sessions need to go too.
1301 */
1302 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1303 {
1304 int hash;
1305 struct hlist_node *walk;
1306 struct hlist_node *tmp;
1307 struct l2tp_session *session;
1308
1309 BUG_ON(tunnel == NULL);
1310
1311 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
1312 tunnel->name);
1313
1314 write_lock_bh(&tunnel->hlist_lock);
1315 tunnel->acpt_newsess = false;
1316 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1317 again:
1318 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1319 session = hlist_entry(walk, struct l2tp_session, hlist);
1320
1321 l2tp_info(session, L2TP_MSG_CONTROL,
1322 "%s: closing session\n", session->name);
1323
1324 hlist_del_init(&session->hlist);
1325
1326 if (test_and_set_bit(0, &session->dead))
1327 goto again;
1328
1329 if (session->ref != NULL)
1330 (*session->ref)(session);
1331
1332 write_unlock_bh(&tunnel->hlist_lock);
1333
1334 __l2tp_session_unhash(session);
1335 l2tp_session_queue_purge(session);
1336
1337 if (session->session_close != NULL)
1338 (*session->session_close)(session);
1339
1340 if (session->deref != NULL)
1341 (*session->deref)(session);
1342
1343 l2tp_session_dec_refcount(session);
1344
1345 write_lock_bh(&tunnel->hlist_lock);
1346
1347 /* Now restart from the beginning of this hash
1348 * chain. We always remove a session from the
1349 * list so we are guaranteed to make forward
1350 * progress.
1351 */
1352 goto again;
1353 }
1354 }
1355 write_unlock_bh(&tunnel->hlist_lock);
1356 }
1357 EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall);
1358
1359 /* Tunnel socket destroy hook for UDP encapsulation */
1360 static void l2tp_udp_encap_destroy(struct sock *sk)
1361 {
1362 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
1363 if (tunnel) {
1364 l2tp_tunnel_closeall(tunnel);
1365 sock_put(sk);
1366 }
1367 }
1368
1369 /* Workqueue tunnel deletion function */
1370 static void l2tp_tunnel_del_work(struct work_struct *work)
1371 {
1372 struct l2tp_tunnel *tunnel = NULL;
1373 struct socket *sock = NULL;
1374 struct sock *sk = NULL;
1375
1376 tunnel = container_of(work, struct l2tp_tunnel, del_work);
1377
1378 l2tp_tunnel_closeall(tunnel);
1379
1380 sk = l2tp_tunnel_sock_lookup(tunnel);
1381 if (!sk)
1382 goto out;
1383
1384 sock = sk->sk_socket;
1385
1386 /* If the tunnel socket was created by userspace, then go through the
1387 * inet layer to shut the socket down, and let userspace close it.
1388 * Otherwise, if we created the socket directly within the kernel, use
1389 * the sk API to release it here.
1390 * In either case the tunnel resources are freed in the socket
1391 * destructor when the tunnel socket goes away.
1392 */
1393 if (tunnel->fd >= 0) {
1394 if (sock)
1395 inet_shutdown(sock, 2);
1396 } else {
1397 if (sock) {
1398 kernel_sock_shutdown(sock, SHUT_RDWR);
1399 sock_release(sock);
1400 }
1401 }
1402
1403 l2tp_tunnel_sock_put(sk);
1404 out:
1405 l2tp_tunnel_dec_refcount(tunnel);
1406 }
1407
1408 /* Create a socket for the tunnel, if one isn't set up by
1409 * userspace. This is used for static tunnels where there is no
1410 * managing L2TP daemon.
1411 *
1412 * Since we don't want these sockets to keep a namespace alive by
1413 * themselves, we drop the socket's namespace refcount after creation.
1414 * These sockets are freed when the namespace exits using the pernet
1415 * exit hook.
1416 */
1417 static int l2tp_tunnel_sock_create(struct net *net,
1418 u32 tunnel_id,
1419 u32 peer_tunnel_id,
1420 struct l2tp_tunnel_cfg *cfg,
1421 struct socket **sockp)
1422 {
1423 int err = -EINVAL;
1424 struct socket *sock = NULL;
1425 struct udp_port_cfg udp_conf;
1426
1427 switch (cfg->encap) {
1428 case L2TP_ENCAPTYPE_UDP:
1429 memset(&udp_conf, 0, sizeof(udp_conf));
1430
1431 #if IS_ENABLED(CONFIG_IPV6)
1432 if (cfg->local_ip6 && cfg->peer_ip6) {
1433 udp_conf.family = AF_INET6;
1434 memcpy(&udp_conf.local_ip6, cfg->local_ip6,
1435 sizeof(udp_conf.local_ip6));
1436 memcpy(&udp_conf.peer_ip6, cfg->peer_ip6,
1437 sizeof(udp_conf.peer_ip6));
1438 udp_conf.use_udp6_tx_checksums =
1439 cfg->udp6_zero_tx_checksums;
1440 udp_conf.use_udp6_rx_checksums =
1441 cfg->udp6_zero_rx_checksums;
1442 } else
1443 #endif
1444 {
1445 udp_conf.family = AF_INET;
1446 udp_conf.local_ip = cfg->local_ip;
1447 udp_conf.peer_ip = cfg->peer_ip;
1448 udp_conf.use_udp_checksums = cfg->use_udp_checksums;
1449 }
1450
1451 udp_conf.local_udp_port = htons(cfg->local_udp_port);
1452 udp_conf.peer_udp_port = htons(cfg->peer_udp_port);
1453
1454 err = udp_sock_create(net, &udp_conf, &sock);
1455 if (err < 0)
1456 goto out;
1457
1458 break;
1459
1460 case L2TP_ENCAPTYPE_IP:
1461 #if IS_ENABLED(CONFIG_IPV6)
1462 if (cfg->local_ip6 && cfg->peer_ip6) {
1463 struct sockaddr_l2tpip6 ip6_addr = {0};
1464
1465 err = sock_create_kern(net, AF_INET6, SOCK_DGRAM,
1466 IPPROTO_L2TP, &sock);
1467 if (err < 0)
1468 goto out;
1469
1470 ip6_addr.l2tp_family = AF_INET6;
1471 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
1472 sizeof(ip6_addr.l2tp_addr));
1473 ip6_addr.l2tp_conn_id = tunnel_id;
1474 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
1475 sizeof(ip6_addr));
1476 if (err < 0)
1477 goto out;
1478
1479 ip6_addr.l2tp_family = AF_INET6;
1480 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
1481 sizeof(ip6_addr.l2tp_addr));
1482 ip6_addr.l2tp_conn_id = peer_tunnel_id;
1483 err = kernel_connect(sock,
1484 (struct sockaddr *) &ip6_addr,
1485 sizeof(ip6_addr), 0);
1486 if (err < 0)
1487 goto out;
1488 } else
1489 #endif
1490 {
1491 struct sockaddr_l2tpip ip_addr = {0};
1492
1493 err = sock_create_kern(net, AF_INET, SOCK_DGRAM,
1494 IPPROTO_L2TP, &sock);
1495 if (err < 0)
1496 goto out;
1497
1498 ip_addr.l2tp_family = AF_INET;
1499 ip_addr.l2tp_addr = cfg->local_ip;
1500 ip_addr.l2tp_conn_id = tunnel_id;
1501 err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
1502 sizeof(ip_addr));
1503 if (err < 0)
1504 goto out;
1505
1506 ip_addr.l2tp_family = AF_INET;
1507 ip_addr.l2tp_addr = cfg->peer_ip;
1508 ip_addr.l2tp_conn_id = peer_tunnel_id;
1509 err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
1510 sizeof(ip_addr), 0);
1511 if (err < 0)
1512 goto out;
1513 }
1514 break;
1515
1516 default:
1517 goto out;
1518 }
1519
1520 out:
1521 *sockp = sock;
1522 if ((err < 0) && sock) {
1523 kernel_sock_shutdown(sock, SHUT_RDWR);
1524 sock_release(sock);
1525 *sockp = NULL;
1526 }
1527
1528 return err;
1529 }
1530
1531 static struct lock_class_key l2tp_socket_class;
1532
1533 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)
1534 {
1535 struct l2tp_tunnel *tunnel = NULL;
1536 int err;
1537 struct socket *sock = NULL;
1538 struct sock *sk = NULL;
1539 struct l2tp_net *pn;
1540 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1541
1542 /* Get the tunnel socket from the fd, which was opened by
1543 * the userspace L2TP daemon. If not specified, create a
1544 * kernel socket.
1545 */
1546 if (fd < 0) {
1547 err = l2tp_tunnel_sock_create(net, tunnel_id, peer_tunnel_id,
1548 cfg, &sock);
1549 if (err < 0)
1550 goto err;
1551 } else {
1552 sock = sockfd_lookup(fd, &err);
1553 if (!sock) {
1554 pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n",
1555 tunnel_id, fd, err);
1556 err = -EBADF;
1557 goto err;
1558 }
1559
1560 /* Reject namespace mismatches */
1561 if (!net_eq(sock_net(sock->sk), net)) {
1562 pr_err("tunl %u: netns mismatch\n", tunnel_id);
1563 err = -EINVAL;
1564 goto err;
1565 }
1566 }
1567
1568 sk = sock->sk;
1569
1570 if (cfg != NULL)
1571 encap = cfg->encap;
1572
1573 /* Quick sanity checks */
1574 err = -EPROTONOSUPPORT;
1575 if (sk->sk_type != SOCK_DGRAM) {
1576 pr_debug("tunl %hu: fd %d wrong socket type\n",
1577 tunnel_id, fd);
1578 goto err;
1579 }
1580 if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
1581 goto err;
1582 switch (encap) {
1583 case L2TP_ENCAPTYPE_UDP:
1584 if (sk->sk_protocol != IPPROTO_UDP) {
1585 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1586 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1587 goto err;
1588 }
1589 break;
1590 case L2TP_ENCAPTYPE_IP:
1591 if (sk->sk_protocol != IPPROTO_L2TP) {
1592 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1593 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1594 goto err;
1595 }
1596 break;
1597 }
1598
1599 /* Check if this socket has already been prepped */
1600 tunnel = l2tp_tunnel(sk);
1601 if (tunnel != NULL) {
1602 /* This socket has already been prepped */
1603 err = -EBUSY;
1604 goto err;
1605 }
1606
1607 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1608 if (tunnel == NULL) {
1609 err = -ENOMEM;
1610 goto err;
1611 }
1612
1613 tunnel->version = version;
1614 tunnel->tunnel_id = tunnel_id;
1615 tunnel->peer_tunnel_id = peer_tunnel_id;
1616 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1617
1618 tunnel->magic = L2TP_TUNNEL_MAGIC;
1619 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1620 rwlock_init(&tunnel->hlist_lock);
1621 tunnel->acpt_newsess = true;
1622
1623 /* The net we belong to */
1624 tunnel->l2tp_net = net;
1625 pn = l2tp_pernet(net);
1626
1627 if (cfg != NULL)
1628 tunnel->debug = cfg->debug;
1629
1630 #if IS_ENABLED(CONFIG_IPV6)
1631 if (sk->sk_family == PF_INET6) {
1632 struct ipv6_pinfo *np = inet6_sk(sk);
1633
1634 if (ipv6_addr_v4mapped(&np->saddr) &&
1635 ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
1636 struct inet_sock *inet = inet_sk(sk);
1637
1638 tunnel->v4mapped = true;
1639 inet->inet_saddr = np->saddr.s6_addr32[3];
1640 inet->inet_rcv_saddr = sk->sk_v6_rcv_saddr.s6_addr32[3];
1641 inet->inet_daddr = sk->sk_v6_daddr.s6_addr32[3];
1642 } else {
1643 tunnel->v4mapped = false;
1644 }
1645 }
1646 #endif
1647
1648 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1649 tunnel->encap = encap;
1650 if (encap == L2TP_ENCAPTYPE_UDP) {
1651 struct udp_tunnel_sock_cfg udp_cfg = { };
1652
1653 udp_cfg.sk_user_data = tunnel;
1654 udp_cfg.encap_type = UDP_ENCAP_L2TPINUDP;
1655 udp_cfg.encap_rcv = l2tp_udp_encap_recv;
1656 udp_cfg.encap_destroy = l2tp_udp_encap_destroy;
1657
1658 setup_udp_tunnel_sock(net, sock, &udp_cfg);
1659 } else {
1660 sk->sk_user_data = tunnel;
1661 }
1662
1663 /* Hook on the tunnel socket destructor so that we can cleanup
1664 * if the tunnel socket goes away.
1665 */
1666 tunnel->old_sk_destruct = sk->sk_destruct;
1667 sk->sk_destruct = &l2tp_tunnel_destruct;
1668 tunnel->sock = sk;
1669 tunnel->fd = fd;
1670 lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock");
1671
1672 sk->sk_allocation = GFP_ATOMIC;
1673
1674 /* Init delete workqueue struct */
1675 INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work);
1676
1677 /* Add tunnel to our list */
1678 INIT_LIST_HEAD(&tunnel->list);
1679 atomic_inc(&l2tp_tunnel_count);
1680
1681 /* Bump the reference count. The tunnel context is deleted
1682 * only when this drops to zero. Must be done before list insertion
1683 */
1684 l2tp_tunnel_inc_refcount(tunnel);
1685 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1686 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1687 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1688
1689 err = 0;
1690 err:
1691 if (tunnelp)
1692 *tunnelp = tunnel;
1693
1694 /* If tunnel's socket was created by the kernel, it doesn't
1695 * have a file.
1696 */
1697 if (sock && sock->file)
1698 sockfd_put(sock);
1699
1700 return err;
1701 }
1702 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1703
1704 /* This function is used by the netlink TUNNEL_DELETE command.
1705 */
1706 void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1707 {
1708 if (!test_and_set_bit(0, &tunnel->dead)) {
1709 l2tp_tunnel_inc_refcount(tunnel);
1710 queue_work(l2tp_wq, &tunnel->del_work);
1711 }
1712 }
1713 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1714
1715 /* Really kill the session.
1716 */
1717 void l2tp_session_free(struct l2tp_session *session)
1718 {
1719 struct l2tp_tunnel *tunnel = session->tunnel;
1720
1721 BUG_ON(atomic_read(&session->ref_count) != 0);
1722
1723 if (tunnel) {
1724 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1725 if (session->session_id != 0)
1726 atomic_dec(&l2tp_session_count);
1727 sock_put(tunnel->sock);
1728 session->tunnel = NULL;
1729 l2tp_tunnel_dec_refcount(tunnel);
1730 }
1731
1732 kfree(session);
1733 }
1734 EXPORT_SYMBOL_GPL(l2tp_session_free);
1735
1736 /* Remove an l2tp session from l2tp_core's hash lists.
1737 * Provides a tidyup interface for pseudowire code which can't just route all
1738 * shutdown via. l2tp_session_delete and a pseudowire-specific session_close
1739 * callback.
1740 */
1741 void __l2tp_session_unhash(struct l2tp_session *session)
1742 {
1743 struct l2tp_tunnel *tunnel = session->tunnel;
1744
1745 /* Remove the session from core hashes */
1746 if (tunnel) {
1747 /* Remove from the per-tunnel hash */
1748 write_lock_bh(&tunnel->hlist_lock);
1749 hlist_del_init(&session->hlist);
1750 write_unlock_bh(&tunnel->hlist_lock);
1751
1752 /* For L2TPv3 we have a per-net hash: remove from there, too */
1753 if (tunnel->version != L2TP_HDR_VER_2) {
1754 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1755 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1756 hlist_del_init_rcu(&session->global_hlist);
1757 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1758 synchronize_rcu();
1759 }
1760 }
1761 }
1762 EXPORT_SYMBOL_GPL(__l2tp_session_unhash);
1763
1764 /* This function is used by the netlink SESSION_DELETE command and by
1765 pseudowire modules.
1766 */
1767 int l2tp_session_delete(struct l2tp_session *session)
1768 {
1769 if (test_and_set_bit(0, &session->dead))
1770 return 0;
1771
1772 if (session->ref)
1773 (*session->ref)(session);
1774 __l2tp_session_unhash(session);
1775 l2tp_session_queue_purge(session);
1776 if (session->session_close != NULL)
1777 (*session->session_close)(session);
1778 if (session->deref)
1779 (*session->deref)(session);
1780 l2tp_session_dec_refcount(session);
1781 return 0;
1782 }
1783 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1784
1785 /* We come here whenever a session's send_seq, cookie_len or
1786 * l2specific_type parameters are set.
1787 */
1788 void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1789 {
1790 if (version == L2TP_HDR_VER_2) {
1791 session->hdr_len = 6;
1792 if (session->send_seq)
1793 session->hdr_len += 4;
1794 } else {
1795 session->hdr_len = 4 + session->cookie_len + session->offset;
1796 session->hdr_len += l2tp_get_l2specific_len(session);
1797 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1798 session->hdr_len += 4;
1799 }
1800
1801 }
1802 EXPORT_SYMBOL_GPL(l2tp_session_set_header_len);
1803
1804 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)
1805 {
1806 struct l2tp_session *session;
1807
1808 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1809 if (session != NULL) {
1810 session->magic = L2TP_SESSION_MAGIC;
1811 session->tunnel = tunnel;
1812
1813 session->session_id = session_id;
1814 session->peer_session_id = peer_session_id;
1815 session->nr = 0;
1816 if (tunnel->version == L2TP_HDR_VER_2)
1817 session->nr_max = 0xffff;
1818 else
1819 session->nr_max = 0xffffff;
1820 session->nr_window_size = session->nr_max / 2;
1821 session->nr_oos_count_max = 4;
1822
1823 /* Use NR of first received packet */
1824 session->reorder_skip = 1;
1825
1826 sprintf(&session->name[0], "sess %u/%u",
1827 tunnel->tunnel_id, session->session_id);
1828
1829 skb_queue_head_init(&session->reorder_q);
1830
1831 INIT_HLIST_NODE(&session->hlist);
1832 INIT_HLIST_NODE(&session->global_hlist);
1833
1834 /* Inherit debug options from tunnel */
1835 session->debug = tunnel->debug;
1836
1837 if (cfg) {
1838 session->pwtype = cfg->pw_type;
1839 session->debug = cfg->debug;
1840 session->mtu = cfg->mtu;
1841 session->mru = cfg->mru;
1842 session->send_seq = cfg->send_seq;
1843 session->recv_seq = cfg->recv_seq;
1844 session->lns_mode = cfg->lns_mode;
1845 session->reorder_timeout = cfg->reorder_timeout;
1846 session->offset = cfg->offset;
1847 session->l2specific_type = cfg->l2specific_type;
1848 session->l2specific_len = cfg->l2specific_len;
1849 session->cookie_len = cfg->cookie_len;
1850 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1851 session->peer_cookie_len = cfg->peer_cookie_len;
1852 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1853 }
1854
1855 if (tunnel->version == L2TP_HDR_VER_2)
1856 session->build_header = l2tp_build_l2tpv2_header;
1857 else
1858 session->build_header = l2tp_build_l2tpv3_header;
1859
1860 l2tp_session_set_header_len(session, tunnel->version);
1861
1862 l2tp_session_inc_refcount(session);
1863
1864 return session;
1865 }
1866
1867 return ERR_PTR(-ENOMEM);
1868 }
1869 EXPORT_SYMBOL_GPL(l2tp_session_create);
1870
1871 /*****************************************************************************
1872 * Init and cleanup
1873 *****************************************************************************/
1874
1875 static __net_init int l2tp_init_net(struct net *net)
1876 {
1877 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1878 int hash;
1879
1880 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1881 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1882
1883 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1884 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1885
1886 spin_lock_init(&pn->l2tp_session_hlist_lock);
1887
1888 return 0;
1889 }
1890
1891 static __net_exit void l2tp_exit_net(struct net *net)
1892 {
1893 struct l2tp_net *pn = l2tp_pernet(net);
1894 struct l2tp_tunnel *tunnel = NULL;
1895
1896 rcu_read_lock_bh();
1897 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
1898 l2tp_tunnel_delete(tunnel);
1899 }
1900 rcu_read_unlock_bh();
1901
1902 flush_workqueue(l2tp_wq);
1903 rcu_barrier();
1904 }
1905
1906 static struct pernet_operations l2tp_net_ops = {
1907 .init = l2tp_init_net,
1908 .exit = l2tp_exit_net,
1909 .id = &l2tp_net_id,
1910 .size = sizeof(struct l2tp_net),
1911 };
1912
1913 static int __init l2tp_init(void)
1914 {
1915 int rc = 0;
1916
1917 rc = register_pernet_device(&l2tp_net_ops);
1918 if (rc)
1919 goto out;
1920
1921 l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0);
1922 if (!l2tp_wq) {
1923 pr_err("alloc_workqueue failed\n");
1924 unregister_pernet_device(&l2tp_net_ops);
1925 rc = -ENOMEM;
1926 goto out;
1927 }
1928
1929 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
1930
1931 out:
1932 return rc;
1933 }
1934
1935 static void __exit l2tp_exit(void)
1936 {
1937 unregister_pernet_device(&l2tp_net_ops);
1938 if (l2tp_wq) {
1939 destroy_workqueue(l2tp_wq);
1940 l2tp_wq = NULL;
1941 }
1942 }
1943
1944 module_init(l2tp_init);
1945 module_exit(l2tp_exit);
1946
1947 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1948 MODULE_DESCRIPTION("L2TP core");
1949 MODULE_LICENSE("GPL");
1950 MODULE_VERSION(L2TP_DRV_VERSION);
1951
1952
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