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[deliverable/linux.git] / net / l2tp / l2tp_core.c
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 the tunnel socket, possibly involving the fs code if the socket is
172 * owned by userspace. A struct sock returned from this function must be
173 * released using l2tp_tunnel_sock_put once you're done with it.
174 */
175 struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel)
176 {
177 int err = 0;
178 struct socket *sock = NULL;
179 struct sock *sk = NULL;
180
181 if (!tunnel)
182 goto out;
183
184 if (tunnel->fd >= 0) {
185 /* Socket is owned by userspace, who might be in the process
186 * of closing it. Look the socket up using the fd to ensure
187 * consistency.
188 */
189 sock = sockfd_lookup(tunnel->fd, &err);
190 if (sock)
191 sk = sock->sk;
192 } else {
193 /* Socket is owned by kernelspace */
194 sk = tunnel->sock;
195 }
196
197 out:
198 return sk;
199 }
200 EXPORT_SYMBOL_GPL(l2tp_tunnel_sock_lookup);
201
202 /* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */
203 void l2tp_tunnel_sock_put(struct sock *sk)
204 {
205 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
206 if (tunnel) {
207 if (tunnel->fd >= 0) {
208 /* Socket is owned by userspace */
209 sockfd_put(sk->sk_socket);
210 }
211 sock_put(sk);
212 }
213 }
214 EXPORT_SYMBOL_GPL(l2tp_tunnel_sock_put);
215
216 /* Lookup a session by id in the global session list
217 */
218 static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
219 {
220 struct l2tp_net *pn = l2tp_pernet(net);
221 struct hlist_head *session_list =
222 l2tp_session_id_hash_2(pn, session_id);
223 struct l2tp_session *session;
224 struct hlist_node *walk;
225
226 rcu_read_lock_bh();
227 hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
228 if (session->session_id == session_id) {
229 rcu_read_unlock_bh();
230 return session;
231 }
232 }
233 rcu_read_unlock_bh();
234
235 return NULL;
236 }
237
238 /* Session hash list.
239 * The session_id SHOULD be random according to RFC2661, but several
240 * L2TP implementations (Cisco and Microsoft) use incrementing
241 * session_ids. So we do a real hash on the session_id, rather than a
242 * simple bitmask.
243 */
244 static inline struct hlist_head *
245 l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
246 {
247 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
248 }
249
250 /* Lookup a session by id
251 */
252 struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
253 {
254 struct hlist_head *session_list;
255 struct l2tp_session *session;
256 struct hlist_node *walk;
257
258 /* In L2TPv3, session_ids are unique over all tunnels and we
259 * sometimes need to look them up before we know the
260 * tunnel.
261 */
262 if (tunnel == NULL)
263 return l2tp_session_find_2(net, session_id);
264
265 session_list = l2tp_session_id_hash(tunnel, session_id);
266 read_lock_bh(&tunnel->hlist_lock);
267 hlist_for_each_entry(session, walk, session_list, hlist) {
268 if (session->session_id == session_id) {
269 read_unlock_bh(&tunnel->hlist_lock);
270 return session;
271 }
272 }
273 read_unlock_bh(&tunnel->hlist_lock);
274
275 return NULL;
276 }
277 EXPORT_SYMBOL_GPL(l2tp_session_find);
278
279 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth)
280 {
281 int hash;
282 struct hlist_node *walk;
283 struct l2tp_session *session;
284 int count = 0;
285
286 read_lock_bh(&tunnel->hlist_lock);
287 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
288 hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) {
289 if (++count > nth) {
290 read_unlock_bh(&tunnel->hlist_lock);
291 return session;
292 }
293 }
294 }
295
296 read_unlock_bh(&tunnel->hlist_lock);
297
298 return NULL;
299 }
300 EXPORT_SYMBOL_GPL(l2tp_session_find_nth);
301
302 /* Lookup a session by interface name.
303 * This is very inefficient but is only used by management interfaces.
304 */
305 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname)
306 {
307 struct l2tp_net *pn = l2tp_pernet(net);
308 int hash;
309 struct hlist_node *walk;
310 struct l2tp_session *session;
311
312 rcu_read_lock_bh();
313 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
314 hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
315 if (!strcmp(session->ifname, ifname)) {
316 rcu_read_unlock_bh();
317 return session;
318 }
319 }
320 }
321
322 rcu_read_unlock_bh();
323
324 return NULL;
325 }
326 EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname);
327
328 /* Lookup a tunnel by id
329 */
330 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
331 {
332 struct l2tp_tunnel *tunnel;
333 struct l2tp_net *pn = l2tp_pernet(net);
334
335 rcu_read_lock_bh();
336 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
337 if (tunnel->tunnel_id == tunnel_id) {
338 rcu_read_unlock_bh();
339 return tunnel;
340 }
341 }
342 rcu_read_unlock_bh();
343
344 return NULL;
345 }
346 EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
347
348 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
349 {
350 struct l2tp_net *pn = l2tp_pernet(net);
351 struct l2tp_tunnel *tunnel;
352 int count = 0;
353
354 rcu_read_lock_bh();
355 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
356 if (++count > nth) {
357 rcu_read_unlock_bh();
358 return tunnel;
359 }
360 }
361
362 rcu_read_unlock_bh();
363
364 return NULL;
365 }
366 EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
367
368 /*****************************************************************************
369 * Receive data handling
370 *****************************************************************************/
371
372 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
373 * number.
374 */
375 static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
376 {
377 struct sk_buff *skbp;
378 struct sk_buff *tmp;
379 u32 ns = L2TP_SKB_CB(skb)->ns;
380 struct l2tp_stats *sstats;
381
382 spin_lock_bh(&session->reorder_q.lock);
383 sstats = &session->stats;
384 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
385 if (L2TP_SKB_CB(skbp)->ns > ns) {
386 __skb_queue_before(&session->reorder_q, skbp, skb);
387 l2tp_dbg(session, L2TP_MSG_SEQ,
388 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
389 session->name, ns, L2TP_SKB_CB(skbp)->ns,
390 skb_queue_len(&session->reorder_q));
391 u64_stats_update_begin(&sstats->syncp);
392 sstats->rx_oos_packets++;
393 u64_stats_update_end(&sstats->syncp);
394 goto out;
395 }
396 }
397
398 __skb_queue_tail(&session->reorder_q, skb);
399
400 out:
401 spin_unlock_bh(&session->reorder_q.lock);
402 }
403
404 /* Dequeue a single skb.
405 */
406 static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
407 {
408 struct l2tp_tunnel *tunnel = session->tunnel;
409 int length = L2TP_SKB_CB(skb)->length;
410 struct l2tp_stats *tstats, *sstats;
411
412 /* We're about to requeue the skb, so return resources
413 * to its current owner (a socket receive buffer).
414 */
415 skb_orphan(skb);
416
417 tstats = &tunnel->stats;
418 u64_stats_update_begin(&tstats->syncp);
419 sstats = &session->stats;
420 u64_stats_update_begin(&sstats->syncp);
421 tstats->rx_packets++;
422 tstats->rx_bytes += length;
423 sstats->rx_packets++;
424 sstats->rx_bytes += length;
425 u64_stats_update_end(&tstats->syncp);
426 u64_stats_update_end(&sstats->syncp);
427
428 if (L2TP_SKB_CB(skb)->has_seq) {
429 /* Bump our Nr */
430 session->nr++;
431 if (tunnel->version == L2TP_HDR_VER_2)
432 session->nr &= 0xffff;
433 else
434 session->nr &= 0xffffff;
435
436 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
437 session->name, session->nr);
438 }
439
440 /* call private receive handler */
441 if (session->recv_skb != NULL)
442 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
443 else
444 kfree_skb(skb);
445
446 if (session->deref)
447 (*session->deref)(session);
448 }
449
450 /* Dequeue skbs from the session's reorder_q, subject to packet order.
451 * Skbs that have been in the queue for too long are simply discarded.
452 */
453 static void l2tp_recv_dequeue(struct l2tp_session *session)
454 {
455 struct sk_buff *skb;
456 struct sk_buff *tmp;
457 struct l2tp_stats *sstats;
458
459 /* If the pkt at the head of the queue has the nr that we
460 * expect to send up next, dequeue it and any other
461 * in-sequence packets behind it.
462 */
463 start:
464 spin_lock_bh(&session->reorder_q.lock);
465 sstats = &session->stats;
466 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
467 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
468 u64_stats_update_begin(&sstats->syncp);
469 sstats->rx_seq_discards++;
470 sstats->rx_errors++;
471 u64_stats_update_end(&sstats->syncp);
472 l2tp_dbg(session, L2TP_MSG_SEQ,
473 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
474 session->name, L2TP_SKB_CB(skb)->ns,
475 L2TP_SKB_CB(skb)->length, session->nr,
476 skb_queue_len(&session->reorder_q));
477 session->reorder_skip = 1;
478 __skb_unlink(skb, &session->reorder_q);
479 kfree_skb(skb);
480 if (session->deref)
481 (*session->deref)(session);
482 continue;
483 }
484
485 if (L2TP_SKB_CB(skb)->has_seq) {
486 if (session->reorder_skip) {
487 l2tp_dbg(session, L2TP_MSG_SEQ,
488 "%s: advancing nr to next pkt: %u -> %u",
489 session->name, session->nr,
490 L2TP_SKB_CB(skb)->ns);
491 session->reorder_skip = 0;
492 session->nr = L2TP_SKB_CB(skb)->ns;
493 }
494 if (L2TP_SKB_CB(skb)->ns != session->nr) {
495 l2tp_dbg(session, L2TP_MSG_SEQ,
496 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
497 session->name, L2TP_SKB_CB(skb)->ns,
498 L2TP_SKB_CB(skb)->length, session->nr,
499 skb_queue_len(&session->reorder_q));
500 goto out;
501 }
502 }
503 __skb_unlink(skb, &session->reorder_q);
504
505 /* Process the skb. We release the queue lock while we
506 * do so to let other contexts process the queue.
507 */
508 spin_unlock_bh(&session->reorder_q.lock);
509 l2tp_recv_dequeue_skb(session, skb);
510 goto start;
511 }
512
513 out:
514 spin_unlock_bh(&session->reorder_q.lock);
515 }
516
517 static inline int l2tp_verify_udp_checksum(struct sock *sk,
518 struct sk_buff *skb)
519 {
520 struct udphdr *uh = udp_hdr(skb);
521 u16 ulen = ntohs(uh->len);
522 __wsum psum;
523
524 if (sk->sk_no_check || skb_csum_unnecessary(skb))
525 return 0;
526
527 #if IS_ENABLED(CONFIG_IPV6)
528 if (sk->sk_family == PF_INET6) {
529 if (!uh->check) {
530 LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
531 return 1;
532 }
533 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
534 !csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
535 &ipv6_hdr(skb)->daddr, ulen,
536 IPPROTO_UDP, skb->csum)) {
537 skb->ip_summed = CHECKSUM_UNNECESSARY;
538 return 0;
539 }
540 skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
541 &ipv6_hdr(skb)->daddr,
542 skb->len, IPPROTO_UDP,
543 0));
544 } else
545 #endif
546 {
547 struct inet_sock *inet;
548 if (!uh->check)
549 return 0;
550 inet = inet_sk(sk);
551 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr,
552 ulen, IPPROTO_UDP, 0);
553
554 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
555 !csum_fold(csum_add(psum, skb->csum)))
556 return 0;
557 skb->csum = psum;
558 }
559
560 return __skb_checksum_complete(skb);
561 }
562
563 /* Do receive processing of L2TP data frames. We handle both L2TPv2
564 * and L2TPv3 data frames here.
565 *
566 * L2TPv2 Data Message Header
567 *
568 * 0 1 2 3
569 * 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
570 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
571 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
572 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
573 * | Tunnel ID | Session ID |
574 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
575 * | Ns (opt) | Nr (opt) |
576 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
577 * | Offset Size (opt) | Offset pad... (opt)
578 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
579 *
580 * Data frames are marked by T=0. All other fields are the same as
581 * those in L2TP control frames.
582 *
583 * L2TPv3 Data Message Header
584 *
585 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
586 * | L2TP Session Header |
587 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
588 * | L2-Specific Sublayer |
589 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
590 * | Tunnel Payload ...
591 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
592 *
593 * L2TPv3 Session Header Over IP
594 *
595 * 0 1 2 3
596 * 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
597 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
598 * | Session ID |
599 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
600 * | Cookie (optional, maximum 64 bits)...
601 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
602 * |
603 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
604 *
605 * L2TPv3 L2-Specific Sublayer Format
606 *
607 * 0 1 2 3
608 * 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
609 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
610 * |x|S|x|x|x|x|x|x| Sequence Number |
611 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
612 *
613 * Cookie value, sublayer format and offset (pad) are negotiated with
614 * the peer when the session is set up. Unlike L2TPv2, we do not need
615 * to parse the packet header to determine if optional fields are
616 * present.
617 *
618 * Caller must already have parsed the frame and determined that it is
619 * a data (not control) frame before coming here. Fields up to the
620 * session-id have already been parsed and ptr points to the data
621 * after the session-id.
622 */
623 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
624 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
625 int length, int (*payload_hook)(struct sk_buff *skb))
626 {
627 struct l2tp_tunnel *tunnel = session->tunnel;
628 int offset;
629 u32 ns, nr;
630 struct l2tp_stats *sstats = &session->stats;
631
632 /* The ref count is increased since we now hold a pointer to
633 * the session. Take care to decrement the refcnt when exiting
634 * this function from now on...
635 */
636 l2tp_session_inc_refcount(session);
637 if (session->ref)
638 (*session->ref)(session);
639
640 /* Parse and check optional cookie */
641 if (session->peer_cookie_len > 0) {
642 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
643 l2tp_info(tunnel, L2TP_MSG_DATA,
644 "%s: cookie mismatch (%u/%u). Discarding.\n",
645 tunnel->name, tunnel->tunnel_id,
646 session->session_id);
647 u64_stats_update_begin(&sstats->syncp);
648 sstats->rx_cookie_discards++;
649 u64_stats_update_end(&sstats->syncp);
650 goto discard;
651 }
652 ptr += session->peer_cookie_len;
653 }
654
655 /* Handle the optional sequence numbers. Sequence numbers are
656 * in different places for L2TPv2 and L2TPv3.
657 *
658 * If we are the LAC, enable/disable sequence numbers under
659 * the control of the LNS. If no sequence numbers present but
660 * we were expecting them, discard frame.
661 */
662 ns = nr = 0;
663 L2TP_SKB_CB(skb)->has_seq = 0;
664 if (tunnel->version == L2TP_HDR_VER_2) {
665 if (hdrflags & L2TP_HDRFLAG_S) {
666 ns = ntohs(*(__be16 *) ptr);
667 ptr += 2;
668 nr = ntohs(*(__be16 *) ptr);
669 ptr += 2;
670
671 /* Store L2TP info in the skb */
672 L2TP_SKB_CB(skb)->ns = ns;
673 L2TP_SKB_CB(skb)->has_seq = 1;
674
675 l2tp_dbg(session, L2TP_MSG_SEQ,
676 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
677 session->name, ns, nr, session->nr);
678 }
679 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
680 u32 l2h = ntohl(*(__be32 *) ptr);
681
682 if (l2h & 0x40000000) {
683 ns = l2h & 0x00ffffff;
684
685 /* Store L2TP info in the skb */
686 L2TP_SKB_CB(skb)->ns = ns;
687 L2TP_SKB_CB(skb)->has_seq = 1;
688
689 l2tp_dbg(session, L2TP_MSG_SEQ,
690 "%s: recv data ns=%u, session nr=%u\n",
691 session->name, ns, session->nr);
692 }
693 }
694
695 /* Advance past L2-specific header, if present */
696 ptr += session->l2specific_len;
697
698 if (L2TP_SKB_CB(skb)->has_seq) {
699 /* Received a packet with sequence numbers. If we're the LNS,
700 * check if we sre sending sequence numbers and if not,
701 * configure it so.
702 */
703 if ((!session->lns_mode) && (!session->send_seq)) {
704 l2tp_info(session, L2TP_MSG_SEQ,
705 "%s: requested to enable seq numbers by LNS\n",
706 session->name);
707 session->send_seq = -1;
708 l2tp_session_set_header_len(session, tunnel->version);
709 }
710 } else {
711 /* No sequence numbers.
712 * If user has configured mandatory sequence numbers, discard.
713 */
714 if (session->recv_seq) {
715 l2tp_warn(session, L2TP_MSG_SEQ,
716 "%s: recv data has no seq numbers when required. Discarding.\n",
717 session->name);
718 u64_stats_update_begin(&sstats->syncp);
719 sstats->rx_seq_discards++;
720 u64_stats_update_end(&sstats->syncp);
721 goto discard;
722 }
723
724 /* If we're the LAC and we're sending sequence numbers, the
725 * LNS has requested that we no longer send sequence numbers.
726 * If we're the LNS and we're sending sequence numbers, the
727 * LAC is broken. Discard the frame.
728 */
729 if ((!session->lns_mode) && (session->send_seq)) {
730 l2tp_info(session, L2TP_MSG_SEQ,
731 "%s: requested to disable seq numbers by LNS\n",
732 session->name);
733 session->send_seq = 0;
734 l2tp_session_set_header_len(session, tunnel->version);
735 } else if (session->send_seq) {
736 l2tp_warn(session, L2TP_MSG_SEQ,
737 "%s: recv data has no seq numbers when required. Discarding.\n",
738 session->name);
739 u64_stats_update_begin(&sstats->syncp);
740 sstats->rx_seq_discards++;
741 u64_stats_update_end(&sstats->syncp);
742 goto discard;
743 }
744 }
745
746 /* Session data offset is handled differently for L2TPv2 and
747 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
748 * the header. For L2TPv3, the offset is negotiated using AVPs
749 * in the session setup control protocol.
750 */
751 if (tunnel->version == L2TP_HDR_VER_2) {
752 /* If offset bit set, skip it. */
753 if (hdrflags & L2TP_HDRFLAG_O) {
754 offset = ntohs(*(__be16 *)ptr);
755 ptr += 2 + offset;
756 }
757 } else
758 ptr += session->offset;
759
760 offset = ptr - optr;
761 if (!pskb_may_pull(skb, offset))
762 goto discard;
763
764 __skb_pull(skb, offset);
765
766 /* If caller wants to process the payload before we queue the
767 * packet, do so now.
768 */
769 if (payload_hook)
770 if ((*payload_hook)(skb))
771 goto discard;
772
773 /* Prepare skb for adding to the session's reorder_q. Hold
774 * packets for max reorder_timeout or 1 second if not
775 * reordering.
776 */
777 L2TP_SKB_CB(skb)->length = length;
778 L2TP_SKB_CB(skb)->expires = jiffies +
779 (session->reorder_timeout ? session->reorder_timeout : HZ);
780
781 /* Add packet to the session's receive queue. Reordering is done here, if
782 * enabled. Saved L2TP protocol info is stored in skb->sb[].
783 */
784 if (L2TP_SKB_CB(skb)->has_seq) {
785 if (session->reorder_timeout != 0) {
786 /* Packet reordering enabled. Add skb to session's
787 * reorder queue, in order of ns.
788 */
789 l2tp_recv_queue_skb(session, skb);
790 } else {
791 /* Packet reordering disabled. Discard out-of-sequence
792 * packets
793 */
794 if (L2TP_SKB_CB(skb)->ns != session->nr) {
795 u64_stats_update_begin(&sstats->syncp);
796 sstats->rx_seq_discards++;
797 u64_stats_update_end(&sstats->syncp);
798 l2tp_dbg(session, L2TP_MSG_SEQ,
799 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
800 session->name, L2TP_SKB_CB(skb)->ns,
801 L2TP_SKB_CB(skb)->length, session->nr,
802 skb_queue_len(&session->reorder_q));
803 goto discard;
804 }
805 skb_queue_tail(&session->reorder_q, skb);
806 }
807 } else {
808 /* No sequence numbers. Add the skb to the tail of the
809 * reorder queue. This ensures that it will be
810 * delivered after all previous sequenced skbs.
811 */
812 skb_queue_tail(&session->reorder_q, skb);
813 }
814
815 /* Try to dequeue as many skbs from reorder_q as we can. */
816 l2tp_recv_dequeue(session);
817
818 l2tp_session_dec_refcount(session);
819
820 return;
821
822 discard:
823 u64_stats_update_begin(&sstats->syncp);
824 sstats->rx_errors++;
825 u64_stats_update_end(&sstats->syncp);
826 kfree_skb(skb);
827
828 if (session->deref)
829 (*session->deref)(session);
830
831 l2tp_session_dec_refcount(session);
832 }
833 EXPORT_SYMBOL(l2tp_recv_common);
834
835 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
836 * here. The skb is not on a list when we get here.
837 * Returns 0 if the packet was a data packet and was successfully passed on.
838 * Returns 1 if the packet was not a good data packet and could not be
839 * forwarded. All such packets are passed up to userspace to deal with.
840 */
841 static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
842 int (*payload_hook)(struct sk_buff *skb))
843 {
844 struct l2tp_session *session = NULL;
845 unsigned char *ptr, *optr;
846 u16 hdrflags;
847 u32 tunnel_id, session_id;
848 u16 version;
849 int length;
850 struct l2tp_stats *tstats;
851
852 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
853 goto discard_bad_csum;
854
855 /* UDP always verifies the packet length. */
856 __skb_pull(skb, sizeof(struct udphdr));
857
858 /* Short packet? */
859 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
860 l2tp_info(tunnel, L2TP_MSG_DATA,
861 "%s: recv short packet (len=%d)\n",
862 tunnel->name, skb->len);
863 goto error;
864 }
865
866 /* Trace packet contents, if enabled */
867 if (tunnel->debug & L2TP_MSG_DATA) {
868 length = min(32u, skb->len);
869 if (!pskb_may_pull(skb, length))
870 goto error;
871
872 pr_debug("%s: recv\n", tunnel->name);
873 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
874 }
875
876 /* Point to L2TP header */
877 optr = ptr = skb->data;
878
879 /* Get L2TP header flags */
880 hdrflags = ntohs(*(__be16 *) ptr);
881
882 /* Check protocol version */
883 version = hdrflags & L2TP_HDR_VER_MASK;
884 if (version != tunnel->version) {
885 l2tp_info(tunnel, L2TP_MSG_DATA,
886 "%s: recv protocol version mismatch: got %d expected %d\n",
887 tunnel->name, version, tunnel->version);
888 goto error;
889 }
890
891 /* Get length of L2TP packet */
892 length = skb->len;
893
894 /* If type is control packet, it is handled by userspace. */
895 if (hdrflags & L2TP_HDRFLAG_T) {
896 l2tp_dbg(tunnel, L2TP_MSG_DATA,
897 "%s: recv control packet, len=%d\n",
898 tunnel->name, length);
899 goto error;
900 }
901
902 /* Skip flags */
903 ptr += 2;
904
905 if (tunnel->version == L2TP_HDR_VER_2) {
906 /* If length is present, skip it */
907 if (hdrflags & L2TP_HDRFLAG_L)
908 ptr += 2;
909
910 /* Extract tunnel and session ID */
911 tunnel_id = ntohs(*(__be16 *) ptr);
912 ptr += 2;
913 session_id = ntohs(*(__be16 *) ptr);
914 ptr += 2;
915 } else {
916 ptr += 2; /* skip reserved bits */
917 tunnel_id = tunnel->tunnel_id;
918 session_id = ntohl(*(__be32 *) ptr);
919 ptr += 4;
920 }
921
922 /* Find the session context */
923 session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id);
924 if (!session || !session->recv_skb) {
925 /* Not found? Pass to userspace to deal with */
926 l2tp_info(tunnel, L2TP_MSG_DATA,
927 "%s: no session found (%u/%u). Passing up.\n",
928 tunnel->name, tunnel_id, session_id);
929 goto error;
930 }
931
932 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
933
934 return 0;
935
936 discard_bad_csum:
937 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
938 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
939 tstats = &tunnel->stats;
940 u64_stats_update_begin(&tstats->syncp);
941 tstats->rx_errors++;
942 u64_stats_update_end(&tstats->syncp);
943 kfree_skb(skb);
944
945 return 0;
946
947 error:
948 /* Put UDP header back */
949 __skb_push(skb, sizeof(struct udphdr));
950
951 return 1;
952 }
953
954 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
955 * Return codes:
956 * 0 : success.
957 * <0: error
958 * >0: skb should be passed up to userspace as UDP.
959 */
960 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
961 {
962 struct l2tp_tunnel *tunnel;
963
964 tunnel = l2tp_sock_to_tunnel(sk);
965 if (tunnel == NULL)
966 goto pass_up;
967
968 l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
969 tunnel->name, skb->len);
970
971 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
972 goto pass_up_put;
973
974 sock_put(sk);
975 return 0;
976
977 pass_up_put:
978 sock_put(sk);
979 pass_up:
980 return 1;
981 }
982 EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
983
984 /************************************************************************
985 * Transmit handling
986 ***********************************************************************/
987
988 /* Build an L2TP header for the session into the buffer provided.
989 */
990 static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
991 {
992 struct l2tp_tunnel *tunnel = session->tunnel;
993 __be16 *bufp = buf;
994 __be16 *optr = buf;
995 u16 flags = L2TP_HDR_VER_2;
996 u32 tunnel_id = tunnel->peer_tunnel_id;
997 u32 session_id = session->peer_session_id;
998
999 if (session->send_seq)
1000 flags |= L2TP_HDRFLAG_S;
1001
1002 /* Setup L2TP header. */
1003 *bufp++ = htons(flags);
1004 *bufp++ = htons(tunnel_id);
1005 *bufp++ = htons(session_id);
1006 if (session->send_seq) {
1007 *bufp++ = htons(session->ns);
1008 *bufp++ = 0;
1009 session->ns++;
1010 session->ns &= 0xffff;
1011 l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
1012 session->name, session->ns);
1013 }
1014
1015 return bufp - optr;
1016 }
1017
1018 static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
1019 {
1020 struct l2tp_tunnel *tunnel = session->tunnel;
1021 char *bufp = buf;
1022 char *optr = bufp;
1023
1024 /* Setup L2TP header. The header differs slightly for UDP and
1025 * IP encapsulations. For UDP, there is 4 bytes of flags.
1026 */
1027 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
1028 u16 flags = L2TP_HDR_VER_3;
1029 *((__be16 *) bufp) = htons(flags);
1030 bufp += 2;
1031 *((__be16 *) bufp) = 0;
1032 bufp += 2;
1033 }
1034
1035 *((__be32 *) bufp) = htonl(session->peer_session_id);
1036 bufp += 4;
1037 if (session->cookie_len) {
1038 memcpy(bufp, &session->cookie[0], session->cookie_len);
1039 bufp += session->cookie_len;
1040 }
1041 if (session->l2specific_len) {
1042 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
1043 u32 l2h = 0;
1044 if (session->send_seq) {
1045 l2h = 0x40000000 | session->ns;
1046 session->ns++;
1047 session->ns &= 0xffffff;
1048 l2tp_dbg(session, L2TP_MSG_SEQ,
1049 "%s: updated ns to %u\n",
1050 session->name, session->ns);
1051 }
1052
1053 *((__be32 *) bufp) = htonl(l2h);
1054 }
1055 bufp += session->l2specific_len;
1056 }
1057 if (session->offset)
1058 bufp += session->offset;
1059
1060 return bufp - optr;
1061 }
1062
1063 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
1064 struct flowi *fl, size_t data_len)
1065 {
1066 struct l2tp_tunnel *tunnel = session->tunnel;
1067 unsigned int len = skb->len;
1068 int error;
1069 struct l2tp_stats *tstats, *sstats;
1070
1071 /* Debug */
1072 if (session->send_seq)
1073 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes, ns=%u\n",
1074 session->name, data_len, session->ns - 1);
1075 else
1076 l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes\n",
1077 session->name, data_len);
1078
1079 if (session->debug & L2TP_MSG_DATA) {
1080 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1081 unsigned char *datap = skb->data + uhlen;
1082
1083 pr_debug("%s: xmit\n", session->name);
1084 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
1085 datap, min_t(size_t, 32, len - uhlen));
1086 }
1087
1088 /* Queue the packet to IP for output */
1089 skb->local_df = 1;
1090 #if IS_ENABLED(CONFIG_IPV6)
1091 if (skb->sk->sk_family == PF_INET6)
1092 error = inet6_csk_xmit(skb, NULL);
1093 else
1094 #endif
1095 error = ip_queue_xmit(skb, fl);
1096
1097 /* Update stats */
1098 tstats = &tunnel->stats;
1099 u64_stats_update_begin(&tstats->syncp);
1100 sstats = &session->stats;
1101 u64_stats_update_begin(&sstats->syncp);
1102 if (error >= 0) {
1103 tstats->tx_packets++;
1104 tstats->tx_bytes += len;
1105 sstats->tx_packets++;
1106 sstats->tx_bytes += len;
1107 } else {
1108 tstats->tx_errors++;
1109 sstats->tx_errors++;
1110 }
1111 u64_stats_update_end(&tstats->syncp);
1112 u64_stats_update_end(&sstats->syncp);
1113
1114 return 0;
1115 }
1116
1117 /* Automatically called when the skb is freed.
1118 */
1119 static void l2tp_sock_wfree(struct sk_buff *skb)
1120 {
1121 sock_put(skb->sk);
1122 }
1123
1124 /* For data skbs that we transmit, we associate with the tunnel socket
1125 * but don't do accounting.
1126 */
1127 static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1128 {
1129 sock_hold(sk);
1130 skb->sk = sk;
1131 skb->destructor = l2tp_sock_wfree;
1132 }
1133
1134 #if IS_ENABLED(CONFIG_IPV6)
1135 static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb,
1136 int udp_len)
1137 {
1138 struct ipv6_pinfo *np = inet6_sk(sk);
1139 struct udphdr *uh = udp_hdr(skb);
1140
1141 if (!skb_dst(skb) || !skb_dst(skb)->dev ||
1142 !(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) {
1143 __wsum csum = skb_checksum(skb, 0, udp_len, 0);
1144 skb->ip_summed = CHECKSUM_UNNECESSARY;
1145 uh->check = csum_ipv6_magic(&np->saddr, &np->daddr, udp_len,
1146 IPPROTO_UDP, csum);
1147 if (uh->check == 0)
1148 uh->check = CSUM_MANGLED_0;
1149 } else {
1150 skb->ip_summed = CHECKSUM_PARTIAL;
1151 skb->csum_start = skb_transport_header(skb) - skb->head;
1152 skb->csum_offset = offsetof(struct udphdr, check);
1153 uh->check = ~csum_ipv6_magic(&np->saddr, &np->daddr,
1154 udp_len, IPPROTO_UDP, 0);
1155 }
1156 }
1157 #endif
1158
1159 /* If caller requires the skb to have a ppp header, the header must be
1160 * inserted in the skb data before calling this function.
1161 */
1162 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1163 {
1164 int data_len = skb->len;
1165 struct l2tp_tunnel *tunnel = session->tunnel;
1166 struct sock *sk = tunnel->sock;
1167 struct flowi *fl;
1168 struct udphdr *uh;
1169 struct inet_sock *inet;
1170 __wsum csum;
1171 int headroom;
1172 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1173 int udp_len;
1174 int ret = NET_XMIT_SUCCESS;
1175
1176 /* Check that there's enough headroom in the skb to insert IP,
1177 * UDP and L2TP headers. If not enough, expand it to
1178 * make room. Adjust truesize.
1179 */
1180 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1181 uhlen + hdr_len;
1182 if (skb_cow_head(skb, headroom)) {
1183 kfree_skb(skb);
1184 return NET_XMIT_DROP;
1185 }
1186
1187 skb_orphan(skb);
1188 /* Setup L2TP header */
1189 session->build_header(session, __skb_push(skb, hdr_len));
1190
1191 /* Reset skb netfilter state */
1192 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1193 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1194 IPSKB_REROUTED);
1195 nf_reset(skb);
1196
1197 bh_lock_sock(sk);
1198 if (sock_owned_by_user(sk)) {
1199 kfree_skb(skb);
1200 ret = NET_XMIT_DROP;
1201 goto out_unlock;
1202 }
1203
1204 /* Get routing info from the tunnel socket */
1205 skb_dst_drop(skb);
1206 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
1207
1208 inet = inet_sk(sk);
1209 fl = &inet->cork.fl;
1210 switch (tunnel->encap) {
1211 case L2TP_ENCAPTYPE_UDP:
1212 /* Setup UDP header */
1213 __skb_push(skb, sizeof(*uh));
1214 skb_reset_transport_header(skb);
1215 uh = udp_hdr(skb);
1216 uh->source = inet->inet_sport;
1217 uh->dest = inet->inet_dport;
1218 udp_len = uhlen + hdr_len + data_len;
1219 uh->len = htons(udp_len);
1220 uh->check = 0;
1221
1222 /* Calculate UDP checksum if configured to do so */
1223 #if IS_ENABLED(CONFIG_IPV6)
1224 if (sk->sk_family == PF_INET6)
1225 l2tp_xmit_ipv6_csum(sk, skb, udp_len);
1226 else
1227 #endif
1228 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1229 skb->ip_summed = CHECKSUM_NONE;
1230 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1231 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1232 skb->ip_summed = CHECKSUM_COMPLETE;
1233 csum = skb_checksum(skb, 0, udp_len, 0);
1234 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1235 inet->inet_daddr,
1236 udp_len, IPPROTO_UDP, csum);
1237 if (uh->check == 0)
1238 uh->check = CSUM_MANGLED_0;
1239 } else {
1240 skb->ip_summed = CHECKSUM_PARTIAL;
1241 skb->csum_start = skb_transport_header(skb) - skb->head;
1242 skb->csum_offset = offsetof(struct udphdr, check);
1243 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1244 inet->inet_daddr,
1245 udp_len, IPPROTO_UDP, 0);
1246 }
1247 break;
1248
1249 case L2TP_ENCAPTYPE_IP:
1250 break;
1251 }
1252
1253 l2tp_skb_set_owner_w(skb, sk);
1254
1255 l2tp_xmit_core(session, skb, fl, data_len);
1256 out_unlock:
1257 bh_unlock_sock(sk);
1258
1259 return ret;
1260 }
1261 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1262
1263 /*****************************************************************************
1264 * Tinnel and session create/destroy.
1265 *****************************************************************************/
1266
1267 /* Tunnel socket destruct hook.
1268 * The tunnel context is deleted only when all session sockets have been
1269 * closed.
1270 */
1271 static void l2tp_tunnel_destruct(struct sock *sk)
1272 {
1273 struct l2tp_tunnel *tunnel;
1274
1275 tunnel = sk->sk_user_data;
1276 if (tunnel == NULL)
1277 goto end;
1278
1279 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
1280
1281 /* Close all sessions */
1282 l2tp_tunnel_closeall(tunnel);
1283
1284 switch (tunnel->encap) {
1285 case L2TP_ENCAPTYPE_UDP:
1286 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1287 (udp_sk(sk))->encap_type = 0;
1288 (udp_sk(sk))->encap_rcv = NULL;
1289 break;
1290 case L2TP_ENCAPTYPE_IP:
1291 break;
1292 }
1293
1294 /* Remove hooks into tunnel socket */
1295 tunnel->sock = NULL;
1296 sk->sk_destruct = tunnel->old_sk_destruct;
1297 sk->sk_user_data = NULL;
1298
1299 /* Call the original destructor */
1300 if (sk->sk_destruct)
1301 (*sk->sk_destruct)(sk);
1302
1303 /* We're finished with the socket */
1304 l2tp_tunnel_dec_refcount(tunnel);
1305
1306 end:
1307 return;
1308 }
1309
1310 /* When the tunnel is closed, all the attached sessions need to go too.
1311 */
1312 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
1313 {
1314 int hash;
1315 struct hlist_node *walk;
1316 struct hlist_node *tmp;
1317 struct l2tp_session *session;
1318
1319 BUG_ON(tunnel == NULL);
1320
1321 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
1322 tunnel->name);
1323
1324 write_lock_bh(&tunnel->hlist_lock);
1325 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1326 again:
1327 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1328 session = hlist_entry(walk, struct l2tp_session, hlist);
1329
1330 l2tp_info(session, L2TP_MSG_CONTROL,
1331 "%s: closing session\n", session->name);
1332
1333 hlist_del_init(&session->hlist);
1334
1335 /* Since we should hold the sock lock while
1336 * doing any unbinding, we need to release the
1337 * lock we're holding before taking that lock.
1338 * Hold a reference to the sock so it doesn't
1339 * disappear as we're jumping between locks.
1340 */
1341 if (session->ref != NULL)
1342 (*session->ref)(session);
1343
1344 write_unlock_bh(&tunnel->hlist_lock);
1345
1346 if (tunnel->version != L2TP_HDR_VER_2) {
1347 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1348
1349 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1350 hlist_del_init_rcu(&session->global_hlist);
1351 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1352 synchronize_rcu();
1353 }
1354
1355 if (session->session_close != NULL)
1356 (*session->session_close)(session);
1357
1358 if (session->deref != NULL)
1359 (*session->deref)(session);
1360
1361 write_lock_bh(&tunnel->hlist_lock);
1362
1363 /* Now restart from the beginning of this hash
1364 * chain. We always remove a session from the
1365 * list so we are guaranteed to make forward
1366 * progress.
1367 */
1368 goto again;
1369 }
1370 }
1371 write_unlock_bh(&tunnel->hlist_lock);
1372 }
1373
1374 /* Really kill the tunnel.
1375 * Come here only when all sessions have been cleared from the tunnel.
1376 */
1377 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
1378 {
1379 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1380
1381 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1382 BUG_ON(tunnel->sock != NULL);
1383
1384 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name);
1385
1386 /* Remove from tunnel list */
1387 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1388 list_del_rcu(&tunnel->list);
1389 kfree_rcu(tunnel, rcu);
1390 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1391
1392 atomic_dec(&l2tp_tunnel_count);
1393 }
1394
1395 /* Create a socket for the tunnel, if one isn't set up by
1396 * userspace. This is used for static tunnels where there is no
1397 * managing L2TP daemon.
1398 */
1399 static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1400 {
1401 int err = -EINVAL;
1402 struct sockaddr_in udp_addr;
1403 #if IS_ENABLED(CONFIG_IPV6)
1404 struct sockaddr_in6 udp6_addr;
1405 struct sockaddr_l2tpip6 ip6_addr;
1406 #endif
1407 struct sockaddr_l2tpip ip_addr;
1408 struct socket *sock = NULL;
1409
1410 switch (cfg->encap) {
1411 case L2TP_ENCAPTYPE_UDP:
1412 #if IS_ENABLED(CONFIG_IPV6)
1413 if (cfg->local_ip6 && cfg->peer_ip6) {
1414 err = sock_create(AF_INET6, SOCK_DGRAM, 0, sockp);
1415 if (err < 0)
1416 goto out;
1417
1418 sock = *sockp;
1419
1420 memset(&udp6_addr, 0, sizeof(udp6_addr));
1421 udp6_addr.sin6_family = AF_INET6;
1422 memcpy(&udp6_addr.sin6_addr, cfg->local_ip6,
1423 sizeof(udp6_addr.sin6_addr));
1424 udp6_addr.sin6_port = htons(cfg->local_udp_port);
1425 err = kernel_bind(sock, (struct sockaddr *) &udp6_addr,
1426 sizeof(udp6_addr));
1427 if (err < 0)
1428 goto out;
1429
1430 udp6_addr.sin6_family = AF_INET6;
1431 memcpy(&udp6_addr.sin6_addr, cfg->peer_ip6,
1432 sizeof(udp6_addr.sin6_addr));
1433 udp6_addr.sin6_port = htons(cfg->peer_udp_port);
1434 err = kernel_connect(sock,
1435 (struct sockaddr *) &udp6_addr,
1436 sizeof(udp6_addr), 0);
1437 if (err < 0)
1438 goto out;
1439 } else
1440 #endif
1441 {
1442 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1443 if (err < 0)
1444 goto out;
1445
1446 sock = *sockp;
1447
1448 memset(&udp_addr, 0, sizeof(udp_addr));
1449 udp_addr.sin_family = AF_INET;
1450 udp_addr.sin_addr = cfg->local_ip;
1451 udp_addr.sin_port = htons(cfg->local_udp_port);
1452 err = kernel_bind(sock, (struct sockaddr *) &udp_addr,
1453 sizeof(udp_addr));
1454 if (err < 0)
1455 goto out;
1456
1457 udp_addr.sin_family = AF_INET;
1458 udp_addr.sin_addr = cfg->peer_ip;
1459 udp_addr.sin_port = htons(cfg->peer_udp_port);
1460 err = kernel_connect(sock,
1461 (struct sockaddr *) &udp_addr,
1462 sizeof(udp_addr), 0);
1463 if (err < 0)
1464 goto out;
1465 }
1466
1467 if (!cfg->use_udp_checksums)
1468 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1469
1470 break;
1471
1472 case L2TP_ENCAPTYPE_IP:
1473 #if IS_ENABLED(CONFIG_IPV6)
1474 if (cfg->local_ip6 && cfg->peer_ip6) {
1475 err = sock_create(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP,
1476 sockp);
1477 if (err < 0)
1478 goto out;
1479
1480 sock = *sockp;
1481
1482 memset(&ip6_addr, 0, sizeof(ip6_addr));
1483 ip6_addr.l2tp_family = AF_INET6;
1484 memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
1485 sizeof(ip6_addr.l2tp_addr));
1486 ip6_addr.l2tp_conn_id = tunnel_id;
1487 err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
1488 sizeof(ip6_addr));
1489 if (err < 0)
1490 goto out;
1491
1492 ip6_addr.l2tp_family = AF_INET6;
1493 memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
1494 sizeof(ip6_addr.l2tp_addr));
1495 ip6_addr.l2tp_conn_id = peer_tunnel_id;
1496 err = kernel_connect(sock,
1497 (struct sockaddr *) &ip6_addr,
1498 sizeof(ip6_addr), 0);
1499 if (err < 0)
1500 goto out;
1501 } else
1502 #endif
1503 {
1504 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP,
1505 sockp);
1506 if (err < 0)
1507 goto out;
1508
1509 sock = *sockp;
1510
1511 memset(&ip_addr, 0, sizeof(ip_addr));
1512 ip_addr.l2tp_family = AF_INET;
1513 ip_addr.l2tp_addr = cfg->local_ip;
1514 ip_addr.l2tp_conn_id = tunnel_id;
1515 err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
1516 sizeof(ip_addr));
1517 if (err < 0)
1518 goto out;
1519
1520 ip_addr.l2tp_family = AF_INET;
1521 ip_addr.l2tp_addr = cfg->peer_ip;
1522 ip_addr.l2tp_conn_id = peer_tunnel_id;
1523 err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
1524 sizeof(ip_addr), 0);
1525 if (err < 0)
1526 goto out;
1527 }
1528 break;
1529
1530 default:
1531 goto out;
1532 }
1533
1534 out:
1535 if ((err < 0) && sock) {
1536 sock_release(sock);
1537 *sockp = NULL;
1538 }
1539
1540 return err;
1541 }
1542
1543 static struct lock_class_key l2tp_socket_class;
1544
1545 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)
1546 {
1547 struct l2tp_tunnel *tunnel = NULL;
1548 int err;
1549 struct socket *sock = NULL;
1550 struct sock *sk = NULL;
1551 struct l2tp_net *pn;
1552 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
1553
1554 /* Get the tunnel socket from the fd, which was opened by
1555 * the userspace L2TP daemon. If not specified, create a
1556 * kernel socket.
1557 */
1558 if (fd < 0) {
1559 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1560 if (err < 0)
1561 goto err;
1562 } else {
1563 err = -EBADF;
1564 sock = sockfd_lookup(fd, &err);
1565 if (!sock) {
1566 pr_err("tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1567 tunnel_id, fd, err);
1568 goto err;
1569 }
1570 }
1571
1572 sk = sock->sk;
1573
1574 if (cfg != NULL)
1575 encap = cfg->encap;
1576
1577 /* Quick sanity checks */
1578 switch (encap) {
1579 case L2TP_ENCAPTYPE_UDP:
1580 err = -EPROTONOSUPPORT;
1581 if (sk->sk_protocol != IPPROTO_UDP) {
1582 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1583 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1584 goto err;
1585 }
1586 break;
1587 case L2TP_ENCAPTYPE_IP:
1588 err = -EPROTONOSUPPORT;
1589 if (sk->sk_protocol != IPPROTO_L2TP) {
1590 pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1591 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1592 goto err;
1593 }
1594 break;
1595 }
1596
1597 /* Check if this socket has already been prepped */
1598 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1599 if (tunnel != NULL) {
1600 /* This socket has already been prepped */
1601 err = -EBUSY;
1602 goto err;
1603 }
1604
1605 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1606 if (tunnel == NULL) {
1607 err = -ENOMEM;
1608 goto err;
1609 }
1610
1611 tunnel->version = version;
1612 tunnel->tunnel_id = tunnel_id;
1613 tunnel->peer_tunnel_id = peer_tunnel_id;
1614 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1615
1616 tunnel->magic = L2TP_TUNNEL_MAGIC;
1617 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1618 rwlock_init(&tunnel->hlist_lock);
1619
1620 /* The net we belong to */
1621 tunnel->l2tp_net = net;
1622 pn = l2tp_pernet(net);
1623
1624 if (cfg != NULL)
1625 tunnel->debug = cfg->debug;
1626
1627 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1628 tunnel->encap = encap;
1629 if (encap == L2TP_ENCAPTYPE_UDP) {
1630 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1631 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1632 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1633 #if IS_ENABLED(CONFIG_IPV6)
1634 if (sk->sk_family == PF_INET6)
1635 udpv6_encap_enable();
1636 else
1637 #endif
1638 udp_encap_enable();
1639 }
1640
1641 sk->sk_user_data = tunnel;
1642
1643 /* Hook on the tunnel socket destructor so that we can cleanup
1644 * if the tunnel socket goes away.
1645 */
1646 tunnel->old_sk_destruct = sk->sk_destruct;
1647 sk->sk_destruct = &l2tp_tunnel_destruct;
1648 tunnel->sock = sk;
1649 tunnel->fd = fd;
1650 lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock");
1651
1652 sk->sk_allocation = GFP_ATOMIC;
1653
1654 /* Add tunnel to our list */
1655 INIT_LIST_HEAD(&tunnel->list);
1656 atomic_inc(&l2tp_tunnel_count);
1657
1658 /* Bump the reference count. The tunnel context is deleted
1659 * only when this drops to zero. Must be done before list insertion
1660 */
1661 l2tp_tunnel_inc_refcount(tunnel);
1662 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1663 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1664 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1665
1666 err = 0;
1667 err:
1668 if (tunnelp)
1669 *tunnelp = tunnel;
1670
1671 /* If tunnel's socket was created by the kernel, it doesn't
1672 * have a file.
1673 */
1674 if (sock && sock->file)
1675 sockfd_put(sock);
1676
1677 return err;
1678 }
1679 EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1680
1681 /* This function is used by the netlink TUNNEL_DELETE command.
1682 */
1683 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1684 {
1685 int err = -EBADF;
1686 struct socket *sock = NULL;
1687 struct sock *sk = NULL;
1688
1689 sk = l2tp_tunnel_sock_lookup(tunnel);
1690 if (!sk)
1691 goto out;
1692
1693 sock = sk->sk_socket;
1694 BUG_ON(!sock);
1695
1696 /* Force the tunnel socket to close. This will eventually
1697 * cause the tunnel to be deleted via the normal socket close
1698 * mechanisms when userspace closes the tunnel socket.
1699 */
1700 err = inet_shutdown(sock, 2);
1701
1702 /* If the tunnel's socket was created by the kernel,
1703 * close the socket here since the socket was not
1704 * created by userspace.
1705 */
1706 if (sock->file == NULL)
1707 err = inet_release(sock);
1708
1709 l2tp_tunnel_sock_put(sk);
1710 out:
1711 return err;
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;
1720
1721 BUG_ON(atomic_read(&session->ref_count) != 0);
1722
1723 tunnel = session->tunnel;
1724 if (tunnel != NULL) {
1725 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1726
1727 /* Delete the session from the hash */
1728 write_lock_bh(&tunnel->hlist_lock);
1729 hlist_del_init(&session->hlist);
1730 write_unlock_bh(&tunnel->hlist_lock);
1731
1732 /* Unlink from the global hash if not L2TPv2 */
1733 if (tunnel->version != L2TP_HDR_VER_2) {
1734 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1735
1736 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1737 hlist_del_init_rcu(&session->global_hlist);
1738 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1739 synchronize_rcu();
1740 }
1741
1742 if (session->session_id != 0)
1743 atomic_dec(&l2tp_session_count);
1744
1745 sock_put(tunnel->sock);
1746
1747 /* This will delete the tunnel context if this
1748 * is the last session on the tunnel.
1749 */
1750 session->tunnel = NULL;
1751 l2tp_tunnel_dec_refcount(tunnel);
1752 }
1753
1754 kfree(session);
1755
1756 return;
1757 }
1758 EXPORT_SYMBOL_GPL(l2tp_session_free);
1759
1760 /* This function is used by the netlink SESSION_DELETE command and by
1761 pseudowire modules.
1762 */
1763 int l2tp_session_delete(struct l2tp_session *session)
1764 {
1765 if (session->session_close != NULL)
1766 (*session->session_close)(session);
1767
1768 l2tp_session_dec_refcount(session);
1769
1770 return 0;
1771 }
1772 EXPORT_SYMBOL_GPL(l2tp_session_delete);
1773
1774
1775 /* We come here whenever a session's send_seq, cookie_len or
1776 * l2specific_len parameters are set.
1777 */
1778 static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
1779 {
1780 if (version == L2TP_HDR_VER_2) {
1781 session->hdr_len = 6;
1782 if (session->send_seq)
1783 session->hdr_len += 4;
1784 } else {
1785 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1786 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1787 session->hdr_len += 4;
1788 }
1789
1790 }
1791
1792 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)
1793 {
1794 struct l2tp_session *session;
1795
1796 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1797 if (session != NULL) {
1798 session->magic = L2TP_SESSION_MAGIC;
1799 session->tunnel = tunnel;
1800
1801 session->session_id = session_id;
1802 session->peer_session_id = peer_session_id;
1803 session->nr = 0;
1804
1805 sprintf(&session->name[0], "sess %u/%u",
1806 tunnel->tunnel_id, session->session_id);
1807
1808 skb_queue_head_init(&session->reorder_q);
1809
1810 INIT_HLIST_NODE(&session->hlist);
1811 INIT_HLIST_NODE(&session->global_hlist);
1812
1813 /* Inherit debug options from tunnel */
1814 session->debug = tunnel->debug;
1815
1816 if (cfg) {
1817 session->pwtype = cfg->pw_type;
1818 session->debug = cfg->debug;
1819 session->mtu = cfg->mtu;
1820 session->mru = cfg->mru;
1821 session->send_seq = cfg->send_seq;
1822 session->recv_seq = cfg->recv_seq;
1823 session->lns_mode = cfg->lns_mode;
1824 session->reorder_timeout = cfg->reorder_timeout;
1825 session->offset = cfg->offset;
1826 session->l2specific_type = cfg->l2specific_type;
1827 session->l2specific_len = cfg->l2specific_len;
1828 session->cookie_len = cfg->cookie_len;
1829 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1830 session->peer_cookie_len = cfg->peer_cookie_len;
1831 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
1832 }
1833
1834 if (tunnel->version == L2TP_HDR_VER_2)
1835 session->build_header = l2tp_build_l2tpv2_header;
1836 else
1837 session->build_header = l2tp_build_l2tpv3_header;
1838
1839 l2tp_session_set_header_len(session, tunnel->version);
1840
1841 /* Bump the reference count. The session context is deleted
1842 * only when this drops to zero.
1843 */
1844 l2tp_session_inc_refcount(session);
1845 l2tp_tunnel_inc_refcount(tunnel);
1846
1847 /* Ensure tunnel socket isn't deleted */
1848 sock_hold(tunnel->sock);
1849
1850 /* Add session to the tunnel's hash list */
1851 write_lock_bh(&tunnel->hlist_lock);
1852 hlist_add_head(&session->hlist,
1853 l2tp_session_id_hash(tunnel, session_id));
1854 write_unlock_bh(&tunnel->hlist_lock);
1855
1856 /* And to the global session list if L2TPv3 */
1857 if (tunnel->version != L2TP_HDR_VER_2) {
1858 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1859
1860 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1861 hlist_add_head_rcu(&session->global_hlist,
1862 l2tp_session_id_hash_2(pn, session_id));
1863 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1864 }
1865
1866 /* Ignore management session in session count value */
1867 if (session->session_id != 0)
1868 atomic_inc(&l2tp_session_count);
1869 }
1870
1871 return session;
1872 }
1873 EXPORT_SYMBOL_GPL(l2tp_session_create);
1874
1875 /*****************************************************************************
1876 * Init and cleanup
1877 *****************************************************************************/
1878
1879 static __net_init int l2tp_init_net(struct net *net)
1880 {
1881 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
1882 int hash;
1883
1884 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
1885 spin_lock_init(&pn->l2tp_tunnel_list_lock);
1886
1887 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1888 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1889
1890 spin_lock_init(&pn->l2tp_session_hlist_lock);
1891
1892 return 0;
1893 }
1894
1895 static struct pernet_operations l2tp_net_ops = {
1896 .init = l2tp_init_net,
1897 .id = &l2tp_net_id,
1898 .size = sizeof(struct l2tp_net),
1899 };
1900
1901 static int __init l2tp_init(void)
1902 {
1903 int rc = 0;
1904
1905 rc = register_pernet_device(&l2tp_net_ops);
1906 if (rc)
1907 goto out;
1908
1909 pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
1910
1911 out:
1912 return rc;
1913 }
1914
1915 static void __exit l2tp_exit(void)
1916 {
1917 unregister_pernet_device(&l2tp_net_ops);
1918 }
1919
1920 module_init(l2tp_init);
1921 module_exit(l2tp_exit);
1922
1923 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1924 MODULE_DESCRIPTION("L2TP core");
1925 MODULE_LICENSE("GPL");
1926 MODULE_VERSION(L2TP_DRV_VERSION);
1927
Linux kernel - Deliverables
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