?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Linux 3.7.4
[linux/fpc-iii.git] / net / l2tp / l2tp_core.c
blob1a9f3723c13cb45b608bbc07fe4a9803df926523
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/inet_common.h>
56 #include <net/xfrm.h>
57 #include <net/protocol.h>
58 #include <net/inet6_connection_sock.h>
59 #include <net/inet_ecn.h>
60 #include <net/ip6_route.h>
61 #include <net/ip6_checksum.h>
62
63 #include <asm/byteorder.h>
64 #include <linux/atomic.h>
65
66 #include "l2tp_core.h"
67
68 #define L2TP_DRV_VERSION "V2.0"
69
70 /* L2TP header constants */
71 #define L2TP_HDRFLAG_T 0x8000
72 #define L2TP_HDRFLAG_L 0x4000
73 #define L2TP_HDRFLAG_S 0x0800
74 #define L2TP_HDRFLAG_O 0x0200
75 #define L2TP_HDRFLAG_P 0x0100
76
77 #define L2TP_HDR_VER_MASK 0x000F
78 #define L2TP_HDR_VER_2 0x0002
79 #define L2TP_HDR_VER_3 0x0003
80
81 /* L2TPv3 default L2-specific sublayer */
82 #define L2TP_SLFLAG_S 0x40000000
83 #define L2TP_SL_SEQ_MASK 0x00ffffff
84
85 #define L2TP_HDR_SIZE_SEQ 10
86 #define L2TP_HDR_SIZE_NOSEQ 6
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
105 /* per-net private data for this module */
106 static unsigned int l2tp_net_id;
107 struct l2tp_net {
108 struct list_head l2tp_tunnel_list;
109 spinlock_t l2tp_tunnel_list_lock;
110 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
111 spinlock_t l2tp_session_hlist_lock;
112 };
113
114 static void l2tp_session_set_header_len(struct l2tp_session *session, int version);
115 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
116 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
117
118 static inline struct l2tp_net *l2tp_pernet(struct net *net)
119 {
120 BUG_ON(!net);
121
122 return net_generic(net, l2tp_net_id);
123 }
124
125
126 /* Tunnel reference counts. Incremented per session that is added to
127 * the tunnel.
128 */
129 static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
130 {
131 atomic_inc(&tunnel->ref_count);
132 }
133
134 static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
135 {
136 if (atomic_dec_and_test(&tunnel->ref_count))
137 l2tp_tunnel_free(tunnel);
138 }
139 #ifdef L2TP_REFCNT_DEBUG
140 #define l2tp_tunnel_inc_refcount(_t) \
141 do { \
142 pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \
143 __func__, __LINE__, (_t)->name, \
144 atomic_read(&_t->ref_count)); \
145 l2tp_tunnel_inc_refcount_1(_t); \
146 } while (0)
147 #define l2tp_tunnel_dec_refcount(_t)
148 do { \
149 pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \
150 __func__, __LINE__, (_t)->name, \
151 atomic_read(&_t->ref_count)); \
152 l2tp_tunnel_dec_refcount_1(_t); \
153 } while (0)
154 #else
155 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
156 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
157 #endif
158
159 /* Session hash global list for L2TPv3.
160 * The session_id SHOULD be random according to RFC3931, but several
161 * L2TP implementations use incrementing session_ids. So we do a real
162 * hash on the session_id, rather than a simple bitmask.
163 */
164 static inline struct hlist_head *
165 l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
166 {
167 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
168
169 }
170
171 /* Lookup a session by id in the global session list
172 */
173 static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
174 {
175 struct l2tp_net *pn = l2tp_pernet(net);
176 struct hlist_head *session_list =
177 l2tp_session_id_hash_2(pn, session_id);
178 struct l2tp_session *session;
179 struct hlist_node *walk;
180
181 rcu_read_lock_bh();
182 hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
183 if (session->session_id == session_id) {
184 rcu_read_unlock_bh();
185 return session;
186 }
187 }
188 rcu_read_unlock_bh();
189
190 return NULL;
191 }
192
193 /* Session hash list.
194 * The session_id SHOULD be random according to RFC2661, but several
195 * L2TP implementations (Cisco and Microsoft) use incrementing
196 * session_ids. So we do a real hash on the session_id, rather than a
197 * simple bitmask.
198 */
199 static inline struct hlist_head *
200 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
201 {
202 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
203 }
204
205 /* Lookup a session by id
206 */
207 struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
208 {
209 struct hlist_head *session_list;
210 struct l2tp_session *session;
211 struct hlist_node *walk;
212
213 /* In L2TPv3, session_ids are unique over all tunnels and we
214 * sometimes need to look them up before we know the
215 * tunnel.
216 */
217 if (tunnel == NULL)
218 return l2tp_session_find_2(net, session_id);
219
220 session_list = l2tp_session_id_hash(tunnel, session_id);
221 read_lock_bh(&tunnel->hlist_lock);
222 hlist_for_each_entry(session, walk, session_list, hlist) {
223 if (session->session_id == session_id) {
224 read_unlock_bh(&tunnel->hlist_lock);
225 return session;
226 }
227 }
228 read_unlock_bh(&tunnel->hlist_lock);
229
230 return NULL;
231 }
232 EXPORT_SYMBOL_GPL(l2tp_session_find);
233
234 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth)
235 {
236 int hash;
237 struct hlist_node *walk;
238 struct l2tp_session *session;
239 int count = 0;
240
241 read_lock_bh(&tunnel->hlist_lock);
242 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
243 hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) {
244 if (++count > nth) {
245 read_unlock_bh(&tunnel->hlist_lock);
246 return session;
247 }
248 }
249 }
250
251 read_unlock_bh(&tunnel->hlist_lock);
252
253 return NULL;
254 }
255 EXPORT_SYMBOL_GPL(l2tp_session_find_nth);
256
257 /* Lookup a session by interface name.
258 * This is very inefficient but is only used by management interfaces.
259 */
260 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname)
261 {
262 struct l2tp_net *pn = l2tp_pernet(net);
263 int hash;
264 struct hlist_node *walk;
265 struct l2tp_session *session;
266
267 rcu_read_lock_bh();
268 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
269 hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
270 if (!strcmp(session->ifname, ifname)) {
271 rcu_read_unlock_bh();
272 return session;
273 }
274 }
275 }
276
277 rcu_read_unlock_bh();
278
279 return NULL;
280 }
281 EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname);
282
283 /* Lookup a tunnel by id
284 */
285 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
286 {
287 struct l2tp_tunnel *tunnel;
288 struct l2tp_net *pn = l2tp_pernet(net);
289
290 rcu_read_lock_bh();
291 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
292 if (tunnel->tunnel_id == tunnel_id) {
293 rcu_read_unlock_bh();
294 return tunnel;
295 }
296 }
297 rcu_read_unlock_bh();
298
299 return NULL;
300 }
301 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
302
303 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
304 {
305 struct l2tp_net *pn = l2tp_pernet(net);
306 struct l2tp_tunnel *tunnel;
307 int count = 0;
308
309 rcu_read_lock_bh();
310 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
311 if (++count > nth) {
312 rcu_read_unlock_bh();
313 return tunnel;
314 }
315 }
316
317 rcu_read_unlock_bh();
318
319 return NULL;
320 }
321 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
322
323 /*****************************************************************************
324 * Receive data handling
325 *****************************************************************************/
326
327 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
328 * number.
329 */
330 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
331 {
332 struct sk_buff *skbp;
333 struct sk_buff *tmp;
334 u32 ns = L2TP_SKB_CB(skb)->ns;
335 struct l2tp_stats *sstats;
336
337 spin_lock_bh(&session->reorder_q.lock);
338 sstats = &session->stats;
339 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
340 if (L2TP_SKB_CB(skbp)->ns > ns) {
341 __skb_queue_before(&session->reorder_q, skbp, skb);
342 l2tp_dbg(session, L2TP_MSG_SEQ,
343 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
344 session->name, ns, L2TP_SKB_CB(skbp)->ns,
345 skb_queue_len(&session->reorder_q));
346 u64_stats_update_begin(&sstats->syncp);
347 sstats->rx_oos_packets++;
348 u64_stats_update_end(&sstats->syncp);
349 goto out;
350 }
351 }
352
353 __skb_queue_tail(&session->reorder_q, skb);
354
355 out:
356 spin_unlock_bh(&session->reorder_q.lock);
357 }
358
359 /* Dequeue a single skb.
360 */
361 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
362 {
363 struct l2tp_tunnel *tunnel = session->tunnel;
364 int length = L2TP_SKB_CB(skb)->length;
365 struct l2tp_stats *tstats, *sstats;
366
367 /* We're about to requeue the skb, so return resources
368 * to its current owner (a socket receive buffer).
369 */
370 skb_orphan(skb);
371
372 tstats = &tunnel->stats;
373 u64_stats_update_begin(&tstats->syncp);
374 sstats = &session->stats;
375 u64_stats_update_begin(&sstats->syncp);
376 tstats->rx_packets++;
377 tstats->rx_bytes += length;
378 sstats->rx_packets++;
379 sstats->rx_bytes += length;
380 u64_stats_update_end(&tstats->syncp);
381 u64_stats_update_end(&sstats->syncp);
382
383 if (L2TP_SKB_CB(skb)->has_seq) {
384 /* Bump our Nr */
385 session->nr++;
386 if (tunnel->version == L2TP_HDR_VER_2)
387 session->nr &= 0xffff;
388 else
389 session->nr &= 0xffffff;
390
391 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
392 session->name, session->nr);
393 }
394
395 /* call private receive handler */
396 if (session->recv_skb != NULL)
397 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
398 else
399 kfree_skb(skb);
400
401 if (session->deref)
402 (*session->deref)(session);
403 }
404
405 /* Dequeue skbs from the session's reorder_q, subject to packet order.
406 * Skbs that have been in the queue for too long are simply discarded.
407 */
408 static void l2tp_recv_dequeue(struct l2tp_session *session)
409 {
410 struct sk_buff *skb;
411 struct sk_buff *tmp;
412 struct l2tp_stats *sstats;
413
414 /* If the pkt at the head of the queue has the nr that we
415 * expect to send up next, dequeue it and any other
416 * in-sequence packets behind it.
417 */
418 start:
419 spin_lock_bh(&session->reorder_q.lock);
420 sstats = &session->stats;
421 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
422 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
423 u64_stats_update_begin(&sstats->syncp);
424 sstats->rx_seq_discards++;
425 sstats->rx_errors++;
426 u64_stats_update_end(&sstats->syncp);
427 l2tp_dbg(session, L2TP_MSG_SEQ,
428 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
429 session->name, L2TP_SKB_CB(skb)->ns,
430 L2TP_SKB_CB(skb)->length, session->nr,
431 skb_queue_len(&session->reorder_q));
432 session->reorder_skip = 1;
433 __skb_unlink(skb, &session->reorder_q);
434 kfree_skb(skb);
435 if (session->deref)
436 (*session->deref)(session);
437 continue;
438 }
439
440 if (L2TP_SKB_CB(skb)->has_seq) {
441 if (session->reorder_skip) {
442 l2tp_dbg(session, L2TP_MSG_SEQ,
443 "%s: advancing nr to next pkt: %u -> %u",
444 session->name, session->nr,
445 L2TP_SKB_CB(skb)->ns);
446 session->reorder_skip = 0;
447 session->nr = L2TP_SKB_CB(skb)->ns;
448 }
449 if (L2TP_SKB_CB(skb)->ns != session->nr) {
450 l2tp_dbg(session, L2TP_MSG_SEQ,
451 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
452 session->name, L2TP_SKB_CB(skb)->ns,
453 L2TP_SKB_CB(skb)->length, session->nr,
454 skb_queue_len(&session->reorder_q));
455 goto out;
456 }
457 }
458 __skb_unlink(skb, &session->reorder_q);
459
460 /* Process the skb. We release the queue lock while we
461 * do so to let other contexts process the queue.
462 */
463 spin_unlock_bh(&session->reorder_q.lock);
464 l2tp_recv_dequeue_skb(session, skb);
465 goto start;
466 }
467
468 out:
469 spin_unlock_bh(&session->reorder_q.lock);
470 }
471
472 static inline int l2tp_verify_udp_checksum(struct sock *sk,
473 struct sk_buff *skb)
474 {
475 struct udphdr *uh = udp_hdr(skb);
476 u16 ulen = ntohs(uh->len);
477 __wsum psum;
478
479 if (sk->sk_no_check || skb_csum_unnecessary(skb))
480 return 0;
481
482 #if IS_ENABLED(CONFIG_IPV6)
483 if (sk->sk_family == PF_INET6) {
484 if (!uh->check) {
485 LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
486 return 1;
487 }
488 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
489 !csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
490 &ipv6_hdr(skb)->daddr, ulen,
491 IPPROTO_UDP, skb->csum)) {
492 skb->ip_summed = CHECKSUM_UNNECESSARY;
493 return 0;
494 }
495 skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
496 &ipv6_hdr(skb)->daddr,
497 skb->len, IPPROTO_UDP,
498 0));
499 } else
500 #endif
501 {
502 struct inet_sock *inet;
503 if (!uh->check)
504 return 0;
505 inet = inet_sk(sk);
506 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr,
507 ulen, IPPROTO_UDP, 0);
508
509 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
510 !csum_fold(csum_add(psum, skb->csum)))
511 return 0;
512 skb->csum = psum;
513 }
514
515 return __skb_checksum_complete(skb);
516 }
517
518 /* Do receive processing of L2TP data frames. We handle both L2TPv2
519 * and L2TPv3 data frames here.
520 *
521 * L2TPv2 Data Message Header
522 *
523 * 0 1 2 3
524 * 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
525 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
526 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
527 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
528 * | Tunnel ID | Session ID |
529 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
530 * | Ns (opt) | Nr (opt) |
531 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
532 * | Offset Size (opt) | Offset pad... (opt)
533 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
534 *
535 * Data frames are marked by T=0. All other fields are the same as
536 * those in L2TP control frames.
537 *
538 * L2TPv3 Data Message Header
539 *
540 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
541 * | L2TP Session Header |
542 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
543 * | L2-Specific Sublayer |
544 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
545 * | Tunnel Payload ...
546 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
547 *
548 * L2TPv3 Session Header Over IP
549 *
550 * 0 1 2 3
551 * 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
552 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
553 * | Session ID |
554 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
555 * | Cookie (optional, maximum 64 bits)...
556 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
557 * |
558 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
559 *
560 * L2TPv3 L2-Specific Sublayer Format
561 *
562 * 0 1 2 3
563 * 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
564 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
565 * |x|S|x|x|x|x|x|x| Sequence Number |
566 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
567 *
568 * Cookie value, sublayer format and offset (pad) are negotiated with
569 * the peer when the session is set up. Unlike L2TPv2, we do not need
570 * to parse the packet header to determine if optional fields are
571 * present.
572 *
573 * Caller must already have parsed the frame and determined that it is
574 * a data (not control) frame before coming here. Fields up to the
575 * session-id have already been parsed and ptr points to the data
576 * after the session-id.
577 */
578 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
579 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
580 int length, int (*payload_hook)(struct sk_buff *skb))
581 {
582 struct l2tp_tunnel *tunnel = session->tunnel;
583 int offset;
584 u32 ns, nr;
585 struct l2tp_stats *sstats = &session->stats;
586
587 /* The ref count is increased since we now hold a pointer to
588 * the session. Take care to decrement the refcnt when exiting
589 * this function from now on...
590 */
591 l2tp_session_inc_refcount(session);
592 if (session->ref)
593 (*session->ref)(session);
594
595 /* Parse and check optional cookie */
596 if (session->peer_cookie_len > 0) {
597 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
598 l2tp_info(tunnel, L2TP_MSG_DATA,
599 "%s: cookie mismatch (%u/%u). Discarding.\n",
600 tunnel->name, tunnel->tunnel_id,
601 session->session_id);
602 u64_stats_update_begin(&sstats->syncp);
603 sstats->rx_cookie_discards++;
604 u64_stats_update_end(&sstats->syncp);
605 goto discard;
606 }
607 ptr += session->peer_cookie_len;
608 }
609
610 /* Handle the optional sequence numbers. Sequence numbers are
611 * in different places for L2TPv2 and L2TPv3.
612 *
613 * If we are the LAC, enable/disable sequence numbers under
614 * the control of the LNS. If no sequence numbers present but
615 * we were expecting them, discard frame.
616 */
617 ns = nr = 0;
618 L2TP_SKB_CB(skb)->has_seq = 0;
619 if (tunnel->version == L2TP_HDR_VER_2) {
620 if (hdrflags & L2TP_HDRFLAG_S) {
621 ns = ntohs(*(__be16 *) ptr);
622 ptr += 2;
623 nr = ntohs(*(__be16 *) ptr);
624 ptr += 2;
625
626 /* Store L2TP info in the skb */
627 L2TP_SKB_CB(skb)->ns = ns;
628 L2TP_SKB_CB(skb)->has_seq = 1;
629
630 l2tp_dbg(session, L2TP_MSG_SEQ,
631 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
632 session->name, ns, nr, session->nr);
633 }
634 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
635 u32 l2h = ntohl(*(__be32 *) ptr);
636
637 if (l2h & 0x40000000) {
638 ns = l2h & 0x00ffffff;
639
640 /* Store L2TP info in the skb */
641 L2TP_SKB_CB(skb)->ns = ns;
642 L2TP_SKB_CB(skb)->has_seq = 1;
643
644 l2tp_dbg(session, L2TP_MSG_SEQ,
645 "%s: recv data ns=%u, session nr=%u\n",
646 session->name, ns, session->nr);
647 }
648 }
649
650 /* Advance past L2-specific header, if present */
651 ptr += session->l2specific_len;
652
653 if (L2TP_SKB_CB(skb)->has_seq) {
654 /* Received a packet with sequence numbers. If we're the LNS,
655 * check if we sre sending sequence numbers and if not,
656 * configure it so.
657 */
658 if ((!session->lns_mode) && (!session->send_seq)) {
659 l2tp_info(session, L2TP_MSG_SEQ,
660 "%s: requested to enable seq numbers by LNS\n",
661 session->name);
662 session->send_seq = -1;
663 l2tp_session_set_header_len(session, tunnel->version);
664 }
665 } else {
666 /* No sequence numbers.
667 * If user has configured mandatory sequence numbers, discard.
668 */
669 if (session->recv_seq) {
670 l2tp_warn(session, L2TP_MSG_SEQ,
671 "%s: recv data has no seq numbers when required. Discarding.\n",
672 session->name);
673 u64_stats_update_begin(&sstats->syncp);
674 sstats->rx_seq_discards++;
675 u64_stats_update_end(&sstats->syncp);
676 goto discard;
677 }
678
679 /* If we're the LAC and we're sending sequence numbers, the
680 * LNS has requested that we no longer send sequence numbers.
681 * If we're the LNS and we're sending sequence numbers, the
682 * LAC is broken. Discard the frame.
683 */
684 if ((!session->lns_mode) && (session->send_seq)) {
685 l2tp_info(session, L2TP_MSG_SEQ,
686 "%s: requested to disable seq numbers by LNS\n",
687 session->name);
688 session->send_seq = 0;
689 l2tp_session_set_header_len(session, tunnel->version);
690 } else if (session->send_seq) {
691 l2tp_warn(session, L2TP_MSG_SEQ,
692 "%s: recv data has no seq numbers when required. Discarding.\n",
693 session->name);
694 u64_stats_update_begin(&sstats->syncp);
695 sstats->rx_seq_discards++;
696 u64_stats_update_end(&sstats->syncp);
697 goto discard;
698 }
699 }
700
701 /* Session data offset is handled differently for L2TPv2 and
702 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
703 * the header. For L2TPv3, the offset is negotiated using AVPs
704 * in the session setup control protocol.
705 */
706 if (tunnel->version == L2TP_HDR_VER_2) {
707 /* If offset bit set, skip it. */
708 if (hdrflags & L2TP_HDRFLAG_O) {
709 offset = ntohs(*(__be16 *)ptr);
710 ptr += 2 + offset;
711 }
712 } else
713 ptr += session->offset;
714
715 offset = ptr - optr;
716 if (!pskb_may_pull(skb, offset))
717 goto discard;
718
719 __skb_pull(skb, offset);
720
721 /* If caller wants to process the payload before we queue the
722 * packet, do so now.
723 */
724 if (payload_hook)
725 if ((*payload_hook)(skb))
726 goto discard;
727
728 /* Prepare skb for adding to the session's reorder_q. Hold
729 * packets for max reorder_timeout or 1 second if not
730 * reordering.
731 */
732 L2TP_SKB_CB(skb)->length = length;
733 L2TP_SKB_CB(skb)->expires = jiffies +
734 (session->reorder_timeout ? session->reorder_timeout : HZ);
735
736 /* Add packet to the session's receive queue. Reordering is done here, if
737 * enabled. Saved L2TP protocol info is stored in skb->sb[].
738 */
739 if (L2TP_SKB_CB(skb)->has_seq) {
740 if (session->reorder_timeout != 0) {
741 /* Packet reordering enabled. Add skb to session's
742 * reorder queue, in order of ns.
743 */
744 l2tp_recv_queue_skb(session, skb);
745 } else {
746 /* Packet reordering disabled. Discard out-of-sequence
747 * packets
748 */
749 if (L2TP_SKB_CB(skb)->ns != session->nr) {
750 u64_stats_update_begin(&sstats->syncp);
751 sstats->rx_seq_discards++;
752 u64_stats_update_end(&sstats->syncp);
753 l2tp_dbg(session, L2TP_MSG_SEQ,
754 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
755 session->name, L2TP_SKB_CB(skb)->ns,
756 L2TP_SKB_CB(skb)->length, session->nr,
757 skb_queue_len(&session->reorder_q));
758 goto discard;
759 }
760 skb_queue_tail(&session->reorder_q, skb);
761 }
762 } else {
763 /* No sequence numbers. Add the skb to the tail of the
764 * reorder queue. This ensures that it will be
765 * delivered after all previous sequenced skbs.
766 */
767 skb_queue_tail(&session->reorder_q, skb);
768 }
769
770 /* Try to dequeue as many skbs from reorder_q as we can. */
771 l2tp_recv_dequeue(session);
772
773 l2tp_session_dec_refcount(session);
774
775 return;
776
777 discard:
778 u64_stats_update_begin(&sstats->syncp);
779 sstats->rx_errors++;
780 u64_stats_update_end(&sstats->syncp);
781 kfree_skb(skb);
782
783 if (session->deref)
784 (*session->deref)(session);
785
786 l2tp_session_dec_refcount(session);
787 }
788 EXPORT_SYMBOL(l2tp_recv_common);
789
790 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
791 * here. The skb is not on a list when we get here.
792 * Returns 0 if the packet was a data packet and was successfully passed on.
793 * Returns 1 if the packet was not a good data packet and could not be
794 * forwarded. All such packets are passed up to userspace to deal with.
795 */
796 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
797 int (*payload_hook)(struct sk_buff *skb))
798 {
799 struct l2tp_session *session = NULL;
800 unsigned char *ptr, *optr;
801 u16 hdrflags;
802 u32 tunnel_id, session_id;
803 u16 version;
804 int length;
805 struct l2tp_stats *tstats;
806
807 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
808 goto discard_bad_csum;
809
810 /* UDP always verifies the packet length. */
811 __skb_pull(skb, sizeof(struct udphdr));
812
813 /* Short packet? */
814 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
815 l2tp_info(tunnel, L2TP_MSG_DATA,
816 "%s: recv short packet (len=%d)\n",
817 tunnel->name, skb->len);
818 goto error;
819 }
820
821 /* Trace packet contents, if enabled */
822 if (tunnel->debug & L2TP_MSG_DATA) {
823 length = min(32u, skb->len);
824 if (!pskb_may_pull(skb, length))
825 goto error;
826
827 pr_debug("%s: recv\n", tunnel->name);
828 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
829 }
830
831 /* Point to L2TP header */
832 optr = ptr = skb->data;
833
834 /* Get L2TP header flags */
835 hdrflags = ntohs(*(__be16 *) ptr);
836
837 /* Check protocol version */
838 version = hdrflags & L2TP_HDR_VER_MASK;
839 if (version != tunnel->version) {
840 l2tp_info(tunnel, L2TP_MSG_DATA,
841 "%s: recv protocol version mismatch: got %d expected %d\n",
842 tunnel->name, version, tunnel->version);
843 goto error;
844 }
845
846 /* Get length of L2TP packet */
847 length = skb->len;
848
849 /* If type is control packet, it is handled by userspace. */
850 if (hdrflags & L2TP_HDRFLAG_T) {
851 l2tp_dbg(tunnel, L2TP_MSG_DATA,
852 "%s: recv control packet, len=%d\n",
853 tunnel->name, length);
854 goto error;
855 }
856
857 /* Skip flags */
858 ptr += 2;
859
860 if (tunnel->version == L2TP_HDR_VER_2) {
861 /* If length is present, skip it */
862 if (hdrflags & L2TP_HDRFLAG_L)
863 ptr += 2;
864
865 /* Extract tunnel and session ID */
866 tunnel_id = ntohs(*(__be16 *) ptr);
867 ptr += 2;
868 session_id = ntohs(*(__be16 *) ptr);
869 ptr += 2;
870 } else {
871 ptr += 2; /* skip reserved bits */
872 tunnel_id = tunnel->tunnel_id;
873 session_id = ntohl(*(__be32 *) ptr);
874 ptr += 4;
875 }
876
877 /* Find the session context */
878 session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id);
879 if (!session || !session->recv_skb) {
880 /* Not found? Pass to userspace to deal with */
881 l2tp_info(tunnel, L2TP_MSG_DATA,
882 "%s: no session found (%u/%u). Passing up.\n",
883 tunnel->name, tunnel_id, session_id);
884 goto error;
885 }
886
887 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
888
889 return 0;
890
891 discard_bad_csum:
892 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
893 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
894 tstats = &tunnel->stats;
895 u64_stats_update_begin(&tstats->syncp);
896 tstats->rx_errors++;
897 u64_stats_update_end(&tstats->syncp);
898 kfree_skb(skb);
899
900 return 0;
901
902 error:
903 /* Put UDP header back */
904 __skb_push(skb, sizeof(struct udphdr));
905
906 return 1;
907 }
908
909 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
910 * Return codes:
911 * 0 : success.
912 * <0: error
913 * >0: skb should be passed up to userspace as UDP.
914 */
915 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
916 {
917 struct l2tp_tunnel *tunnel;
918
919 tunnel = l2tp_sock_to_tunnel(sk);
920 if (tunnel == NULL)
921 goto pass_up;
922
923 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
924 tunnel->name, skb->len);
925
926 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
927 goto pass_up_put;
928
929 sock_put(sk);
930 return 0;
931
932 pass_up_put:
933 sock_put(sk);
934 pass_up:
935 return 1;
936 }
937 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
938
939 /************************************************************************
940 * Transmit handling
941 ***********************************************************************/
942
943 /* Build an L2TP header for the session into the buffer provided.
944 */
945 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
946 {
947 struct l2tp_tunnel *tunnel = session->tunnel;
948 __be16 *bufp = buf;
949 __be16 *optr = buf;
950 u16 flags = L2TP_HDR_VER_2;
951 u32 tunnel_id = tunnel->peer_tunnel_id;
952 u32 session_id = session->peer_session_id;
953
954 if (session->send_seq)
955 flags |= L2TP_HDRFLAG_S;
956
957 /* Setup L2TP header. */
958 *bufp++ = htons(flags);
959 *bufp++ = htons(tunnel_id);
960 *bufp++ = htons(session_id);
961 if (session->send_seq) {
962 *bufp++ = htons(session->ns);
963 *bufp++ = 0;
964 session->ns++;
965 session->ns &= 0xffff;
966 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
967 session->name, session->ns);
968 }
969
970 return bufp - optr;
971 }
972
973 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
974 {
975 struct l2tp_tunnel *tunnel = session->tunnel;
976 char *bufp = buf;
977 char *optr = bufp;
978
979 /* Setup L2TP header. The header differs slightly for UDP and
980 * IP encapsulations. For UDP, there is 4 bytes of flags.
981 */
982 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
983 u16 flags = L2TP_HDR_VER_3;
984 *((__be16 *) bufp) = htons(flags);
985 bufp += 2;
986 *((__be16 *) bufp) = 0;
987 bufp += 2;
988 }
989
990 *((__be32 *) bufp) = htonl(session->peer_session_id);
991 bufp += 4;
992 if (session->cookie_len) {
993 memcpy(bufp, &session->cookie[0], session->cookie_len);
994 bufp += session->cookie_len;
995 }
996 if (session->l2specific_len) {
997 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
998 u32 l2h = 0;
999 if (session->send_seq) {
1000 l2h = 0x40000000 | session->ns;
1001 session->ns++;
1002 session->ns &= 0xffffff;
1003 l2tp_dbg(session, L2TP_MSG_SEQ,
1004 "%s: updated ns to %u\n",
1005 session->name, session->ns);
1006 }
1007
1008 *((__be32 *) bufp) = htonl(l2h);
1009 }
1010 bufp += session->l2specific_len;
1011 }
1012 if (session->offset)
1013 bufp += session->offset;
1014
1015 return bufp - optr;
1016 }
1017
1018 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1019 struct flowi *fl, size_t data_len)
1020 {
1021 struct l2tp_tunnel *tunnel = session->tunnel;
1022 unsigned int len = skb->len;
1023 int error;
1024 struct l2tp_stats *tstats, *sstats;
1025
1026 /* Debug */
1027 if (session->send_seq)
1028 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes, ns=%u\n",
1029 session->name, data_len, session->ns - 1);
1030 else
1031 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes\n",
1032 session->name, data_len);
1033
1034 if (session->debug & L2TP_MSG_DATA) {
1035 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1036 unsigned char *datap = skb->data + uhlen;
1037
1038 pr_debug("%s: xmit\n", session->name);
1039 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
1040 datap, min_t(size_t, 32, len - uhlen));
1041 }
1042
1043 /* Queue the packet to IP for output */
1044 skb->local_df = 1;
1045 #if IS_ENABLED(CONFIG_IPV6)
1046 if (skb->sk->sk_family == PF_INET6)
1047 error = inet6_csk_xmit(skb, NULL);
1048 else
1049 #endif
1050 error = ip_queue_xmit(skb, fl);
1051
1052 /* Update stats */
1053 tstats = &tunnel->stats;
1054 u64_stats_update_begin(&tstats->syncp);
1055 sstats = &session->stats;
1056 u64_stats_update_begin(&sstats->syncp);
1057 if (error >= 0) {
1058 tstats->tx_packets++;
1059 tstats->tx_bytes += len;
1060 sstats->tx_packets++;
1061 sstats->tx_bytes += len;
1062 } else {
1063 tstats->tx_errors++;
1064 sstats->tx_errors++;
1065 }
1066 u64_stats_update_end(&tstats->syncp);
1067 u64_stats_update_end(&sstats->syncp);
1068
1069 return 0;
1070 }
1071
1072 /* Automatically called when the skb is freed.
1073 */
1074 static void l2tp_sock_wfree(struct sk_buff *skb)
1075 {
1076 sock_put(skb->sk);
1077 }
1078
1079 /* For data skbs that we transmit, we associate with the tunnel socket
1080 * but don't do accounting.
1081 */
1082 static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1083 {
1084 sock_hold(sk);
1085 skb->sk = sk;
1086 skb->destructor = l2tp_sock_wfree;
1087 }
1088
1089 #if IS_ENABLED(CONFIG_IPV6)
1090 static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb,
1091 int udp_len)
1092 {
1093 struct ipv6_pinfo *np = inet6_sk(sk);
1094 struct udphdr *uh = udp_hdr(skb);
1095
1096 if (!skb_dst(skb) || !skb_dst(skb)->dev ||
1097 !(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) {
1098 __wsum csum = skb_checksum(skb, 0, udp_len, 0);
1099 skb->ip_summed = CHECKSUM_UNNECESSARY;
1100 uh->check = csum_ipv6_magic(&np->saddr, &np->daddr, udp_len,
1101 IPPROTO_UDP, csum);
1102 if (uh->check == 0)
1103 uh->check = CSUM_MANGLED_0;
1104 } else {
1105 skb->ip_summed = CHECKSUM_PARTIAL;
1106 skb->csum_start = skb_transport_header(skb) - skb->head;
1107 skb->csum_offset = offsetof(struct udphdr, check);
1108 uh->check = ~csum_ipv6_magic(&np->saddr, &np->daddr,
1109 udp_len, IPPROTO_UDP, 0);
1110 }
1111 }
1112 #endif
1113
1114 /* If caller requires the skb to have a ppp header, the header must be
1115 * inserted in the skb data before calling this function.
1116 */
1117 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1118 {
1119 int data_len = skb->len;
1120 struct l2tp_tunnel *tunnel = session->tunnel;
1121 struct sock *sk = tunnel->sock;
1122 struct flowi *fl;
1123 struct udphdr *uh;
1124 struct inet_sock *inet;
1125 __wsum csum;
1126 int old_headroom;
1127 int new_headroom;
1128 int headroom;
1129 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1130 int udp_len;
1131 int ret = NET_XMIT_SUCCESS;
1132
1133 /* Check that there's enough headroom in the skb to insert IP,
1134 * UDP and L2TP headers. If not enough, expand it to
1135 * make room. Adjust truesize.
1136 */
1137 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1138 uhlen + hdr_len;
1139 old_headroom = skb_headroom(skb);
1140 if (skb_cow_head(skb, headroom)) {
1141 kfree_skb(skb);
1142 return NET_XMIT_DROP;
1143 }
1144
1145 new_headroom = skb_headroom(skb);
1146 skb_orphan(skb);
1147 skb->truesize += new_headroom - old_headroom;
1148
1149 /* Setup L2TP header */
1150 session->build_header(session, __skb_push(skb, hdr_len));
1151
1152 /* Reset skb netfilter state */
1153 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1154 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1155 IPSKB_REROUTED);
1156 nf_reset(skb);
1157
1158 bh_lock_sock(sk);
1159 if (sock_owned_by_user(sk)) {
1160 kfree_skb(skb);
1161 ret = NET_XMIT_DROP;
1162 goto out_unlock;
1163 }
1164
1165 /* Get routing info from the tunnel socket */
1166 skb_dst_drop(skb);
1167 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
1168
1169 inet = inet_sk(sk);
1170 fl = &inet->cork.fl;
1171 switch (tunnel->encap) {
1172 case L2TP_ENCAPTYPE_UDP:
1173 /* Setup UDP header */
1174 __skb_push(skb, sizeof(*uh));
1175 skb_reset_transport_header(skb);
1176 uh = udp_hdr(skb);
1177 uh->source = inet->inet_sport;
1178 uh->dest = inet->inet_dport;
1179 udp_len = uhlen + hdr_len + data_len;
1180 uh->len = htons(udp_len);
1181 uh->check = 0;
1182
1183 /* Calculate UDP checksum if configured to do so */
1184 #if IS_ENABLED(CONFIG_IPV6)
1185 if (sk->sk_family == PF_INET6)
1186 l2tp_xmit_ipv6_csum(sk, skb, udp_len);
1187 else
1188 #endif
1189 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1190 skb->ip_summed = CHECKSUM_NONE;
1191 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1192 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1193 skb->ip_summed = CHECKSUM_COMPLETE;
1194 csum = skb_checksum(skb, 0, udp_len, 0);
1195 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1196 inet->inet_daddr,
1197 udp_len, IPPROTO_UDP, csum);
1198 if (uh->check == 0)
1199 uh->check = CSUM_MANGLED_0;
1200 } else {
1201 skb->ip_summed = CHECKSUM_PARTIAL;
1202 skb->csum_start = skb_transport_header(skb) - skb->head;
1203 skb->csum_offset = offsetof(struct udphdr, check);
1204 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1205 inet->inet_daddr,
1206 udp_len, IPPROTO_UDP, 0);
1207 }
1208 break;
1209
1210 case L2TP_ENCAPTYPE_IP:
1211 break;
1212 }
1213
1214 l2tp_skb_set_owner_w(skb, sk);
1215
1216 l2tp_xmit_core(session, skb, fl, data_len);
1217 out_unlock:
1218 bh_unlock_sock(sk);
1219
1220 return ret;
1221 }
1222 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1223
1224 /*****************************************************************************
1225 * Tinnel and session create/destroy.
1226 *****************************************************************************/
1227
1228 /* Tunnel socket destruct hook.
1229 * The tunnel context is deleted only when all session sockets have been
1230 * closed.
1231 */
1232 static void l2tp_tunnel_destruct(struct sock *sk)
1233 {
1234 struct l2tp_tunnel *tunnel;
1235
1236 tunnel = sk->sk_user_data;
1237 if (tunnel == NULL)
1238 goto end;
1239
1240 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
1241
1242 /* Close all sessions */
1243 l2tp_tunnel_closeall(tunnel);
1244
1245 switch (tunnel->encap) {
1246 case L2TP_ENCAPTYPE_UDP:
1247 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1248 (udp_sk(sk))->encap_type = 0;
1249 (udp_sk(sk))->encap_rcv = NULL;
1250 break;
1251 case L2TP_ENCAPTYPE_IP:
1252 break;
1253 }
1254
1255 /* Remove hooks into tunnel socket */
1256 tunnel->sock = NULL;
1257 sk->sk_destruct = tunnel->old_sk_destruct;
1258 sk->sk_user_data = NULL;
1259
1260 /* Call the original destructor */
1261 if (sk->sk_destruct)
1262 (*sk->sk_destruct)(sk);
1263
1264 /* We're finished with the socket */
1265 l2tp_tunnel_dec_refcount(tunnel);
1266
1267 end:
1268 return;
1269 }
1270
1271 /* When the tunnel is closed, all the attached sessions need to go too.
1272 */
1273 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1274 {
1275 int hash;
1276 struct hlist_node *walk;
1277 struct hlist_node *tmp;
1278 struct l2tp_session *session;
1279
1280 BUG_ON(tunnel == NULL);
1281
1282 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
1283 tunnel->name);
1284
1285 write_lock_bh(&tunnel->hlist_lock);
1286 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1287 again:
1288 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1289 session = hlist_entry(walk, struct l2tp_session, hlist);
1290
1291 l2tp_info(session, L2TP_MSG_CONTROL,
1292 "%s: closing session\n", session->name);
1293
1294 hlist_del_init(&session->hlist);
1295
1296 /* Since we should hold the sock lock while
1297 * doing any unbinding, we need to release the
1298 * lock we're holding before taking that lock.
1299 * Hold a reference to the sock so it doesn't
1300 * disappear as we're jumping between locks.
1301 */
1302 if (session->ref != NULL)
1303 (*session->ref)(session);
1304
1305 write_unlock_bh(&tunnel->hlist_lock);
1306
1307 if (tunnel->version != L2TP_HDR_VER_2) {
1308 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1309
1310 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1311 hlist_del_init_rcu(&session->global_hlist);
1312 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1313 synchronize_rcu();
1314 }
1315
1316 if (session->session_close != NULL)
1317 (*session->session_close)(session);
1318
1319 if (session->deref != NULL)
1320 (*session->deref)(session);
1321
1322 write_lock_bh(&tunnel->hlist_lock);
1323
1324 /* Now restart from the beginning of this hash
1325 * chain. We always remove a session from the
1326 * list so we are guaranteed to make forward
1327 * progress.
1328 */
1329 goto again;
1330 }
1331 }
1332 write_unlock_bh(&tunnel->hlist_lock);
1333 }
1334
1335 /* Really kill the tunnel.
1336 * Come here only when all sessions have been cleared from the tunnel.
1337 */
1338 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
1339 {
1340 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1341
1342 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1343 BUG_ON(tunnel->sock != NULL);
1344
1345 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name);
1346
1347 /* Remove from tunnel list */
1348 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1349 list_del_rcu(&tunnel->list);
1350 kfree_rcu(tunnel, rcu);
1351 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1352
1353 atomic_dec(&l2tp_tunnel_count);
1354 }
1355
1356 /* Create a socket for the tunnel, if one isn't set up by
1357 * userspace. This is used for static tunnels where there is no
1358 * managing L2TP daemon.
1359 */
1360 static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1361 {
1362 int err = -EINVAL;
1363 struct sockaddr_in udp_addr;
1364 #if IS_ENABLED(CONFIG_IPV6)
1365 struct sockaddr_in6 udp6_addr;
1366 struct sockaddr_l2tpip6 ip6_addr;
1367 #endif
1368 struct sockaddr_l2tpip ip_addr;
1369 struct socket *sock = NULL;
1370
1371 switch (cfg->encap) {
1372 case L2TP_ENCAPTYPE_UDP:
1373 #if IS_ENABLED(CONFIG_IPV6)
1374 if (cfg->local_ip6 && cfg->peer_ip6) {
1375 err = sock_create(AF_INET6, SOCK_DGRAM, 0, sockp);
1376 if (err < 0)
1377 goto out;
1378
1379 sock = *sockp;
1380
1381 memset(&udp6_addr, 0, sizeof(udp6_addr));
1382 udp6_addr.sin6_family = AF_INET6;
1383 memcpy(&udp6_addr.sin6_addr, cfg->local_ip6,
1384 sizeof(udp6_addr.sin6_addr));
1385 udp6_addr.sin6_port = htons(cfg->local_udp_port);
1386 err = kernel_bind(sock, (struct sockaddr *) &udp6_addr,
1387 sizeof(udp6_addr));
1388 if (err < 0)
1389 goto out;
1390
1391 udp6_addr.sin6_family = AF_INET6;
1392 memcpy(&udp6_addr.sin6_addr, cfg->peer_ip6,
1393 sizeof(udp6_addr.sin6_addr));
1394 udp6_addr.sin6_port = htons(cfg->peer_udp_port);
1395 err = kernel_connect(sock,
1396 (struct sockaddr *) &udp6_addr,
1397 sizeof(udp6_addr), 0);
1398 if (err < 0)
1399 goto out;
1400 } else
1401 #endif
1402 {
1403 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1404 if (err < 0)
1405 goto out;
1406
1407 sock = *sockp;
1408
1409 memset(&udp_addr, 0, sizeof(udp_addr));
1410 udp_addr.sin_family = AF_INET;
1411 udp_addr.sin_addr = cfg->local_ip;
1412 udp_addr.sin_port = htons(cfg->local_udp_port);
1413 err = kernel_bind(sock, (struct sockaddr *) &udp_addr,
1414 sizeof(udp_addr));
1415 if (err < 0)
1416 goto out;
1417
1418 udp_addr.sin_family = AF_INET;
1419 udp_addr.sin_addr = cfg->peer_ip;
1420 udp_addr.sin_port = htons(cfg->peer_udp_port);
1421 err = kernel_connect(sock,
1422 (struct sockaddr *) &udp_addr,
1423 sizeof(udp_addr), 0);
1424 if (err < 0)
1425 goto out;
1426 }
1427
1428 if (!cfg->use_udp_checksums)
1429 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1430
1431 break;
1432
1433 case L2TP_ENCAPTYPE_IP:
1434 #if IS_ENABLED(CONFIG_IPV6)
1435 if (cfg->local_ip6 && cfg->peer_ip6) {
1436 err = sock_create(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP,
1437 sockp);
1438 if (err < 0)
1439 goto out;
1440
1441 sock = *sockp;
1442
1443 memset(&ip6_addr, 0, sizeof(ip6_addr));
1444 ip6_addr.l2tp_family = AF_INET6;
1445 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
1446 sizeof(ip6_addr.l2tp_addr));
1447 ip6_addr.l2tp_conn_id = tunnel_id;
1448 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
1449 sizeof(ip6_addr));
1450 if (err < 0)
1451 goto out;
1452
1453 ip6_addr.l2tp_family = AF_INET6;
1454 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
1455 sizeof(ip6_addr.l2tp_addr));
1456 ip6_addr.l2tp_conn_id = peer_tunnel_id;
1457 err = kernel_connect(sock,
1458 (struct sockaddr *) &ip6_addr,
1459 sizeof(ip6_addr), 0);
1460 if (err < 0)
1461 goto out;
1462 } else
1463 #endif
1464 {
1465 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP,
1466 sockp);
1467 if (err < 0)
1468 goto out;
1469
1470 sock = *sockp;
1471
1472 memset(&ip_addr, 0, sizeof(ip_addr));
1473 ip_addr.l2tp_family = AF_INET;
1474 ip_addr.l2tp_addr = cfg->local_ip;
1475 ip_addr.l2tp_conn_id = tunnel_id;
1476 err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
1477 sizeof(ip_addr));
1478 if (err < 0)
1479 goto out;
1480
1481 ip_addr.l2tp_family = AF_INET;
1482 ip_addr.l2tp_addr = cfg->peer_ip;
1483 ip_addr.l2tp_conn_id = peer_tunnel_id;
1484 err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
1485 sizeof(ip_addr), 0);
1486 if (err < 0)
1487 goto out;
1488 }
1489 break;
1490
1491 default:
1492 goto out;
1493 }
1494
1495 out:
1496 if ((err < 0) && sock) {
1497 sock_release(sock);
1498 *sockp = NULL;
1499 }
1500
1501 return err;
1502 }
1503
1504 static struct lock_class_key l2tp_socket_class;
1505
1506 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)
1507 {
1508 struct l2tp_tunnel *tunnel = NULL;
1509 int err;
1510 struct socket *sock = NULL;
1511 struct sock *sk = NULL;
1512 struct l2tp_net *pn;
1513 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1514
1515 /* Get the tunnel socket from the fd, which was opened by
1516 * the userspace L2TP daemon. If not specified, create a
1517 * kernel socket.
1518 */
1519 if (fd < 0) {
1520 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1521 if (err < 0)
1522 goto err;
1523 } else {
1524 err = -EBADF;
1525 sock = sockfd_lookup(fd, &err);
1526 if (!sock) {
1527 pr_err("tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1528 tunnel_id, fd, err);
1529 goto err;
1530 }
1531 }
1532
1533 sk = sock->sk;
1534
1535 if (cfg != NULL)
1536 encap = cfg->encap;
1537
1538 /* Quick sanity checks */
1539 switch (encap) {
1540 case L2TP_ENCAPTYPE_UDP:
1541 err = -EPROTONOSUPPORT;
1542 if (sk->sk_protocol != IPPROTO_UDP) {
1543 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1544 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1545 goto err;
1546 }
1547 break;
1548 case L2TP_ENCAPTYPE_IP:
1549 err = -EPROTONOSUPPORT;
1550 if (sk->sk_protocol != IPPROTO_L2TP) {
1551 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1552 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1553 goto err;
1554 }
1555 break;
1556 }
1557
1558 /* Check if this socket has already been prepped */
1559 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1560 if (tunnel != NULL) {
1561 /* This socket has already been prepped */
1562 err = -EBUSY;
1563 goto err;
1564 }
1565
1566 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1567 if (tunnel == NULL) {
1568 err = -ENOMEM;
1569 goto err;
1570 }
1571
1572 tunnel->version = version;
1573 tunnel->tunnel_id = tunnel_id;
1574 tunnel->peer_tunnel_id = peer_tunnel_id;
1575 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1576
1577 tunnel->magic = L2TP_TUNNEL_MAGIC;
1578 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1579 rwlock_init(&tunnel->hlist_lock);
1580
1581 /* The net we belong to */
1582 tunnel->l2tp_net = net;
1583 pn = l2tp_pernet(net);
1584
1585 if (cfg != NULL)
1586 tunnel->debug = cfg->debug;
1587
1588 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1589 tunnel->encap = encap;
1590 if (encap == L2TP_ENCAPTYPE_UDP) {
1591 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1592 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1593 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1594 #if IS_ENABLED(CONFIG_IPV6)
1595 if (sk->sk_family == PF_INET6)
1596 udpv6_encap_enable();
1597 else
1598 #endif
1599 udp_encap_enable();
1600 }
1601
1602 sk->sk_user_data = tunnel;
1603
1604 /* Hook on the tunnel socket destructor so that we can cleanup
1605 * if the tunnel socket goes away.
1606 */
1607 tunnel->old_sk_destruct = sk->sk_destruct;
1608 sk->sk_destruct = &l2tp_tunnel_destruct;
1609 tunnel->sock = sk;
1610 lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock");
1611
1612 sk->sk_allocation = GFP_ATOMIC;
1613
1614 /* Add tunnel to our list */
1615 INIT_LIST_HEAD(&tunnel->list);
1616 atomic_inc(&l2tp_tunnel_count);
1617
1618 /* Bump the reference count. The tunnel context is deleted
1619 * only when this drops to zero. Must be done before list insertion
1620 */
1621 l2tp_tunnel_inc_refcount(tunnel);
1622 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1623 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1624 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1625
1626 err = 0;
1627 err:
1628 if (tunnelp)
1629 *tunnelp = tunnel;
1630
1631 /* If tunnel's socket was created by the kernel, it doesn't
1632 * have a file.
1633 */
1634 if (sock && sock->file)
1635 sockfd_put(sock);
1636
1637 return err;
1638 }
1639 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1640
1641 /* This function is used by the netlink TUNNEL_DELETE command.
1642 */
1643 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1644 {
1645 int err = 0;
1646 struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL;
1647
1648 /* Force the tunnel socket to close. This will eventually
1649 * cause the tunnel to be deleted via the normal socket close
1650 * mechanisms when userspace closes the tunnel socket.
1651 */
1652 if (sock != NULL) {
1653 err = inet_shutdown(sock, 2);
1654
1655 /* If the tunnel's socket was created by the kernel,
1656 * close the socket here since the socket was not
1657 * created by userspace.
1658 */
1659 if (sock->file == NULL)
1660 err = inet_release(sock);
1661 }
1662
1663 return err;
1664 }
1665 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1666
1667 /* Really kill the session.
1668 */
1669 void l2tp_session_free(struct l2tp_session *session)
1670 {
1671 struct l2tp_tunnel *tunnel;
1672
1673 BUG_ON(atomic_read(&session->ref_count) != 0);
1674
1675 tunnel = session->tunnel;
1676 if (tunnel != NULL) {
1677 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1678
1679 /* Delete the session from the hash */
1680 write_lock_bh(&tunnel->hlist_lock);
1681 hlist_del_init(&session->hlist);
1682 write_unlock_bh(&tunnel->hlist_lock);
1683
1684 /* Unlink from the global hash if not L2TPv2 */
1685 if (tunnel->version != L2TP_HDR_VER_2) {
1686 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1687
1688 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1689 hlist_del_init_rcu(&session->global_hlist);
1690 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1691 synchronize_rcu();
1692 }
1693
1694 if (session->session_id != 0)
1695 atomic_dec(&l2tp_session_count);
1696
1697 sock_put(tunnel->sock);
1698
1699 /* This will delete the tunnel context if this
1700 * is the last session on the tunnel.
1701 */
1702 session->tunnel = NULL;
1703 l2tp_tunnel_dec_refcount(tunnel);
1704 }
1705
1706 kfree(session);
1707
1708 return;
1709 }
1710 EXPORT_SYMBOL_GPL(l2tp_session_free);
1711
1712 /* This function is used by the netlink SESSION_DELETE command and by
1713 pseudowire modules.
1714 */
1715 int l2tp_session_delete(struct l2tp_session *session)
1716 {
1717 if (session->session_close != NULL)
1718 (*session->session_close)(session);
1719
1720 l2tp_session_dec_refcount(session);
1721
1722 return 0;
1723 }
1724 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1725
1726
1727 /* We come here whenever a session's send_seq, cookie_len or
1728 * l2specific_len parameters are set.
1729 */
1730 static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1731 {
1732 if (version == L2TP_HDR_VER_2) {
1733 session->hdr_len = 6;
1734 if (session->send_seq)
1735 session->hdr_len += 4;
1736 } else {
1737 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1738 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1739 session->hdr_len += 4;
1740 }
1741
1742 }
1743
1744 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)
1745 {
1746 struct l2tp_session *session;
1747
1748 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1749 if (session != NULL) {
1750 session->magic = L2TP_SESSION_MAGIC;
1751 session->tunnel = tunnel;
1752
1753 session->session_id = session_id;
1754 session->peer_session_id = peer_session_id;
1755 session->nr = 0;
1756
1757 sprintf(&session->name[0], "sess %u/%u",
1758 tunnel->tunnel_id, session->session_id);
1759
1760 skb_queue_head_init(&session->reorder_q);
1761
1762 INIT_HLIST_NODE(&session->hlist);
1763 INIT_HLIST_NODE(&session->global_hlist);
1764
1765 /* Inherit debug options from tunnel */
1766 session->debug = tunnel->debug;
1767
1768 if (cfg) {
1769 session->pwtype = cfg->pw_type;
1770 session->debug = cfg->debug;
1771 session->mtu = cfg->mtu;
1772 session->mru = cfg->mru;
1773 session->send_seq = cfg->send_seq;
1774 session->recv_seq = cfg->recv_seq;
1775 session->lns_mode = cfg->lns_mode;
1776 session->reorder_timeout = cfg->reorder_timeout;
1777 session->offset = cfg->offset;
1778 session->l2specific_type = cfg->l2specific_type;
1779 session->l2specific_len = cfg->l2specific_len;
1780 session->cookie_len = cfg->cookie_len;
1781 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1782 session->peer_cookie_len = cfg->peer_cookie_len;
1783 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1784 }
1785
1786 if (tunnel->version == L2TP_HDR_VER_2)
1787 session->build_header = l2tp_build_l2tpv2_header;
1788 else
1789 session->build_header = l2tp_build_l2tpv3_header;
1790
1791 l2tp_session_set_header_len(session, tunnel->version);
1792
1793 /* Bump the reference count. The session context is deleted
1794 * only when this drops to zero.
1795 */
1796 l2tp_session_inc_refcount(session);
1797 l2tp_tunnel_inc_refcount(tunnel);
1798
1799 /* Ensure tunnel socket isn't deleted */
1800 sock_hold(tunnel->sock);
1801
1802 /* Add session to the tunnel's hash list */
1803 write_lock_bh(&tunnel->hlist_lock);
1804 hlist_add_head(&session->hlist,
1805 l2tp_session_id_hash(tunnel, session_id));
1806 write_unlock_bh(&tunnel->hlist_lock);
1807
1808 /* And to the global session list if L2TPv3 */
1809 if (tunnel->version != L2TP_HDR_VER_2) {
1810 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1811
1812 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1813 hlist_add_head_rcu(&session->global_hlist,
1814 l2tp_session_id_hash_2(pn, session_id));
1815 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1816 }
1817
1818 /* Ignore management session in session count value */
1819 if (session->session_id != 0)
1820 atomic_inc(&l2tp_session_count);
1821 }
1822
1823 return session;
1824 }
1825 EXPORT_SYMBOL_GPL(l2tp_session_create);
1826
1827 /*****************************************************************************
1828 * Init and cleanup
1829 *****************************************************************************/
1830
1831 static __net_init int l2tp_init_net(struct net *net)
1832 {
1833 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1834 int hash;
1835
1836 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1837 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1838
1839 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1840 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1841
1842 spin_lock_init(&pn->l2tp_session_hlist_lock);
1843
1844 return 0;
1845 }
1846
1847 static struct pernet_operations l2tp_net_ops = {
1848 .init = l2tp_init_net,
1849 .id = &l2tp_net_id,
1850 .size = sizeof(struct l2tp_net),
1851 };
1852
1853 static int __init l2tp_init(void)
1854 {
1855 int rc = 0;
1856
1857 rc = register_pernet_device(&l2tp_net_ops);
1858 if (rc)
1859 goto out;
1860
1861 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
1862
1863 out:
1864 return rc;
1865 }
1866
1867 static void __exit l2tp_exit(void)
1868 {
1869 unregister_pernet_device(&l2tp_net_ops);
1870 }
1871
1872 module_init(l2tp_init);
1873 module_exit(l2tp_exit);
1874
1875 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1876 MODULE_DESCRIPTION("L2TP core");
1877 MODULE_LICENSE("GPL");
1878 MODULE_VERSION(L2TP_DRV_VERSION);
1879
Linux with added FPC-III support