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James Chapmanfd558d12010-04-02 06:18:33 +00001/*
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#include <linux/module.h>
22#include <linux/string.h>
23#include <linux/list.h>
James Chapmane02d4942010-04-02 06:19:16 +000024#include <linux/rculist.h>
James Chapmanfd558d12010-04-02 06:18:33 +000025#include <linux/uaccess.h>
26
27#include <linux/kernel.h>
28#include <linux/spinlock.h>
29#include <linux/kthread.h>
30#include <linux/sched.h>
31#include <linux/slab.h>
32#include <linux/errno.h>
33#include <linux/jiffies.h>
34
35#include <linux/netdevice.h>
36#include <linux/net.h>
37#include <linux/inetdevice.h>
38#include <linux/skbuff.h>
39#include <linux/init.h>
James Chapman0d767512010-04-02 06:19:00 +000040#include <linux/in.h>
James Chapmanfd558d12010-04-02 06:18:33 +000041#include <linux/ip.h>
42#include <linux/udp.h>
James Chapman0d767512010-04-02 06:19:00 +000043#include <linux/l2tp.h>
James Chapmanfd558d12010-04-02 06:18:33 +000044#include <linux/hash.h>
45#include <linux/sort.h>
46#include <linux/file.h>
47#include <linux/nsproxy.h>
48#include <net/net_namespace.h>
49#include <net/netns/generic.h>
50#include <net/dst.h>
51#include <net/ip.h>
52#include <net/udp.h>
James Chapman309795f2010-04-02 06:19:10 +000053#include <net/inet_common.h>
James Chapmanfd558d12010-04-02 06:18:33 +000054#include <net/xfrm.h>
James Chapman0d767512010-04-02 06:19:00 +000055#include <net/protocol.h>
James Chapmanfd558d12010-04-02 06:18:33 +000056
57#include <asm/byteorder.h>
58#include <asm/atomic.h>
59
60#include "l2tp_core.h"
61
62#define L2TP_DRV_VERSION "V2.0"
63
64/* L2TP header constants */
65#define L2TP_HDRFLAG_T 0x8000
66#define L2TP_HDRFLAG_L 0x4000
67#define L2TP_HDRFLAG_S 0x0800
68#define L2TP_HDRFLAG_O 0x0200
69#define L2TP_HDRFLAG_P 0x0100
70
71#define L2TP_HDR_VER_MASK 0x000F
72#define L2TP_HDR_VER_2 0x0002
James Chapmanf7faffa2010-04-02 06:18:49 +000073#define L2TP_HDR_VER_3 0x0003
James Chapmanfd558d12010-04-02 06:18:33 +000074
75/* L2TPv3 default L2-specific sublayer */
76#define L2TP_SLFLAG_S 0x40000000
77#define L2TP_SL_SEQ_MASK 0x00ffffff
78
79#define L2TP_HDR_SIZE_SEQ 10
80#define L2TP_HDR_SIZE_NOSEQ 6
81
82/* Default trace flags */
83#define L2TP_DEFAULT_DEBUG_FLAGS 0
84
85#define PRINTK(_mask, _type, _lvl, _fmt, args...) \
86 do { \
87 if ((_mask) & (_type)) \
88 printk(_lvl "L2TP: " _fmt, ##args); \
89 } while (0)
90
91/* Private data stored for received packets in the skb.
92 */
93struct l2tp_skb_cb {
James Chapmanf7faffa2010-04-02 06:18:49 +000094 u32 ns;
James Chapmanfd558d12010-04-02 06:18:33 +000095 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
102static atomic_t l2tp_tunnel_count;
103static atomic_t l2tp_session_count;
104
105/* per-net private data for this module */
106static unsigned int l2tp_net_id;
107struct l2tp_net {
108 struct list_head l2tp_tunnel_list;
James Chapmane02d4942010-04-02 06:19:16 +0000109 spinlock_t l2tp_tunnel_list_lock;
James Chapmanf7faffa2010-04-02 06:18:49 +0000110 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
James Chapmane02d4942010-04-02 06:19:16 +0000111 spinlock_t l2tp_session_hlist_lock;
James Chapmanfd558d12010-04-02 06:18:33 +0000112};
113
stephen hemmingerfc130842010-10-21 07:50:46 +0000114static void l2tp_session_set_header_len(struct l2tp_session *session, int version);
115static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
116static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
117
James Chapmanfd558d12010-04-02 06:18:33 +0000118static 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
stephen hemmingerfc130842010-10-21 07:50:46 +0000125
126/* Tunnel reference counts. Incremented per session that is added to
127 * the tunnel.
128 */
129static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
130{
131 atomic_inc(&tunnel->ref_count);
132}
133
134static 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) do { \
141 printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
142 l2tp_tunnel_inc_refcount_1(_t); \
143 } while (0)
144#define l2tp_tunnel_dec_refcount(_t) do { \
145 printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
146 l2tp_tunnel_dec_refcount_1(_t); \
147 } while (0)
148#else
149#define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
150#define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
151#endif
152
James Chapmanf7faffa2010-04-02 06:18:49 +0000153/* Session hash global list for L2TPv3.
154 * The session_id SHOULD be random according to RFC3931, but several
155 * L2TP implementations use incrementing session_ids. So we do a real
156 * hash on the session_id, rather than a simple bitmask.
157 */
158static inline struct hlist_head *
159l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
160{
161 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
162
163}
164
165/* Lookup a session by id in the global session list
166 */
167static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
168{
169 struct l2tp_net *pn = l2tp_pernet(net);
170 struct hlist_head *session_list =
171 l2tp_session_id_hash_2(pn, session_id);
172 struct l2tp_session *session;
173 struct hlist_node *walk;
174
James Chapmane02d4942010-04-02 06:19:16 +0000175 rcu_read_lock_bh();
176 hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
James Chapmanf7faffa2010-04-02 06:18:49 +0000177 if (session->session_id == session_id) {
James Chapmane02d4942010-04-02 06:19:16 +0000178 rcu_read_unlock_bh();
James Chapmanf7faffa2010-04-02 06:18:49 +0000179 return session;
180 }
181 }
James Chapmane02d4942010-04-02 06:19:16 +0000182 rcu_read_unlock_bh();
James Chapmanf7faffa2010-04-02 06:18:49 +0000183
184 return NULL;
185}
186
James Chapmanfd558d12010-04-02 06:18:33 +0000187/* Session hash list.
188 * The session_id SHOULD be random according to RFC2661, but several
189 * L2TP implementations (Cisco and Microsoft) use incrementing
190 * session_ids. So we do a real hash on the session_id, rather than a
191 * simple bitmask.
192 */
193static inline struct hlist_head *
194l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
195{
196 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
197}
198
199/* Lookup a session by id
200 */
James Chapmanf7faffa2010-04-02 06:18:49 +0000201struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
James Chapmanfd558d12010-04-02 06:18:33 +0000202{
James Chapmanf7faffa2010-04-02 06:18:49 +0000203 struct hlist_head *session_list;
James Chapmanfd558d12010-04-02 06:18:33 +0000204 struct l2tp_session *session;
205 struct hlist_node *walk;
206
James Chapmanf7faffa2010-04-02 06:18:49 +0000207 /* In L2TPv3, session_ids are unique over all tunnels and we
208 * sometimes need to look them up before we know the
209 * tunnel.
210 */
211 if (tunnel == NULL)
212 return l2tp_session_find_2(net, session_id);
213
214 session_list = l2tp_session_id_hash(tunnel, session_id);
James Chapmanfd558d12010-04-02 06:18:33 +0000215 read_lock_bh(&tunnel->hlist_lock);
216 hlist_for_each_entry(session, walk, session_list, hlist) {
217 if (session->session_id == session_id) {
218 read_unlock_bh(&tunnel->hlist_lock);
219 return session;
220 }
221 }
222 read_unlock_bh(&tunnel->hlist_lock);
223
224 return NULL;
225}
226EXPORT_SYMBOL_GPL(l2tp_session_find);
227
228struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth)
229{
230 int hash;
231 struct hlist_node *walk;
232 struct l2tp_session *session;
233 int count = 0;
234
235 read_lock_bh(&tunnel->hlist_lock);
236 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
237 hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) {
238 if (++count > nth) {
239 read_unlock_bh(&tunnel->hlist_lock);
240 return session;
241 }
242 }
243 }
244
245 read_unlock_bh(&tunnel->hlist_lock);
246
247 return NULL;
248}
249EXPORT_SYMBOL_GPL(l2tp_session_find_nth);
250
James Chapman309795f2010-04-02 06:19:10 +0000251/* Lookup a session by interface name.
252 * This is very inefficient but is only used by management interfaces.
253 */
254struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname)
255{
256 struct l2tp_net *pn = l2tp_pernet(net);
257 int hash;
258 struct hlist_node *walk;
259 struct l2tp_session *session;
260
James Chapmane02d4942010-04-02 06:19:16 +0000261 rcu_read_lock_bh();
James Chapman309795f2010-04-02 06:19:10 +0000262 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
James Chapmane02d4942010-04-02 06:19:16 +0000263 hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
James Chapman309795f2010-04-02 06:19:10 +0000264 if (!strcmp(session->ifname, ifname)) {
James Chapmane02d4942010-04-02 06:19:16 +0000265 rcu_read_unlock_bh();
James Chapman309795f2010-04-02 06:19:10 +0000266 return session;
267 }
268 }
269 }
270
James Chapmane02d4942010-04-02 06:19:16 +0000271 rcu_read_unlock_bh();
James Chapman309795f2010-04-02 06:19:10 +0000272
273 return NULL;
274}
275EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname);
276
James Chapmanfd558d12010-04-02 06:18:33 +0000277/* Lookup a tunnel by id
278 */
279struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
280{
281 struct l2tp_tunnel *tunnel;
282 struct l2tp_net *pn = l2tp_pernet(net);
283
James Chapmane02d4942010-04-02 06:19:16 +0000284 rcu_read_lock_bh();
285 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
James Chapmanfd558d12010-04-02 06:18:33 +0000286 if (tunnel->tunnel_id == tunnel_id) {
James Chapmane02d4942010-04-02 06:19:16 +0000287 rcu_read_unlock_bh();
James Chapmanfd558d12010-04-02 06:18:33 +0000288 return tunnel;
289 }
290 }
James Chapmane02d4942010-04-02 06:19:16 +0000291 rcu_read_unlock_bh();
James Chapmanfd558d12010-04-02 06:18:33 +0000292
293 return NULL;
294}
295EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
296
297struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
298{
299 struct l2tp_net *pn = l2tp_pernet(net);
300 struct l2tp_tunnel *tunnel;
301 int count = 0;
302
James Chapmane02d4942010-04-02 06:19:16 +0000303 rcu_read_lock_bh();
304 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
James Chapmanfd558d12010-04-02 06:18:33 +0000305 if (++count > nth) {
James Chapmane02d4942010-04-02 06:19:16 +0000306 rcu_read_unlock_bh();
James Chapmanfd558d12010-04-02 06:18:33 +0000307 return tunnel;
308 }
309 }
310
James Chapmane02d4942010-04-02 06:19:16 +0000311 rcu_read_unlock_bh();
James Chapmanfd558d12010-04-02 06:18:33 +0000312
313 return NULL;
314}
315EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
316
317/*****************************************************************************
318 * Receive data handling
319 *****************************************************************************/
320
321/* Queue a skb in order. We come here only if the skb has an L2TP sequence
322 * number.
323 */
324static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
325{
326 struct sk_buff *skbp;
327 struct sk_buff *tmp;
James Chapmanf7faffa2010-04-02 06:18:49 +0000328 u32 ns = L2TP_SKB_CB(skb)->ns;
James Chapmanfd558d12010-04-02 06:18:33 +0000329
330 spin_lock_bh(&session->reorder_q.lock);
331 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
332 if (L2TP_SKB_CB(skbp)->ns > ns) {
333 __skb_queue_before(&session->reorder_q, skbp, skb);
334 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
335 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
336 session->name, ns, L2TP_SKB_CB(skbp)->ns,
337 skb_queue_len(&session->reorder_q));
338 session->stats.rx_oos_packets++;
339 goto out;
340 }
341 }
342
343 __skb_queue_tail(&session->reorder_q, skb);
344
345out:
346 spin_unlock_bh(&session->reorder_q.lock);
347}
348
349/* Dequeue a single skb.
350 */
351static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
352{
353 struct l2tp_tunnel *tunnel = session->tunnel;
354 int length = L2TP_SKB_CB(skb)->length;
355
356 /* We're about to requeue the skb, so return resources
357 * to its current owner (a socket receive buffer).
358 */
359 skb_orphan(skb);
360
361 tunnel->stats.rx_packets++;
362 tunnel->stats.rx_bytes += length;
363 session->stats.rx_packets++;
364 session->stats.rx_bytes += length;
365
366 if (L2TP_SKB_CB(skb)->has_seq) {
367 /* Bump our Nr */
368 session->nr++;
James Chapmanf7faffa2010-04-02 06:18:49 +0000369 if (tunnel->version == L2TP_HDR_VER_2)
370 session->nr &= 0xffff;
371 else
372 session->nr &= 0xffffff;
373
James Chapmanfd558d12010-04-02 06:18:33 +0000374 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
375 "%s: updated nr to %hu\n", session->name, session->nr);
376 }
377
378 /* call private receive handler */
379 if (session->recv_skb != NULL)
380 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
381 else
382 kfree_skb(skb);
383
384 if (session->deref)
385 (*session->deref)(session);
386}
387
388/* Dequeue skbs from the session's reorder_q, subject to packet order.
389 * Skbs that have been in the queue for too long are simply discarded.
390 */
391static void l2tp_recv_dequeue(struct l2tp_session *session)
392{
393 struct sk_buff *skb;
394 struct sk_buff *tmp;
395
396 /* If the pkt at the head of the queue has the nr that we
397 * expect to send up next, dequeue it and any other
398 * in-sequence packets behind it.
399 */
400 spin_lock_bh(&session->reorder_q.lock);
401 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
402 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
403 session->stats.rx_seq_discards++;
404 session->stats.rx_errors++;
405 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
James Chapmanf7faffa2010-04-02 06:18:49 +0000406 "%s: oos pkt %u len %d discarded (too old), "
407 "waiting for %u, reorder_q_len=%d\n",
James Chapmanfd558d12010-04-02 06:18:33 +0000408 session->name, L2TP_SKB_CB(skb)->ns,
409 L2TP_SKB_CB(skb)->length, session->nr,
410 skb_queue_len(&session->reorder_q));
411 __skb_unlink(skb, &session->reorder_q);
412 kfree_skb(skb);
413 if (session->deref)
414 (*session->deref)(session);
415 continue;
416 }
417
418 if (L2TP_SKB_CB(skb)->has_seq) {
419 if (L2TP_SKB_CB(skb)->ns != session->nr) {
420 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
James Chapmanf7faffa2010-04-02 06:18:49 +0000421 "%s: holding oos pkt %u len %d, "
422 "waiting for %u, reorder_q_len=%d\n",
James Chapmanfd558d12010-04-02 06:18:33 +0000423 session->name, L2TP_SKB_CB(skb)->ns,
424 L2TP_SKB_CB(skb)->length, session->nr,
425 skb_queue_len(&session->reorder_q));
426 goto out;
427 }
428 }
429 __skb_unlink(skb, &session->reorder_q);
430
431 /* Process the skb. We release the queue lock while we
432 * do so to let other contexts process the queue.
433 */
434 spin_unlock_bh(&session->reorder_q.lock);
435 l2tp_recv_dequeue_skb(session, skb);
436 spin_lock_bh(&session->reorder_q.lock);
437 }
438
439out:
440 spin_unlock_bh(&session->reorder_q.lock);
441}
442
443static inline int l2tp_verify_udp_checksum(struct sock *sk,
444 struct sk_buff *skb)
445{
446 struct udphdr *uh = udp_hdr(skb);
447 u16 ulen = ntohs(uh->len);
448 struct inet_sock *inet;
449 __wsum psum;
450
451 if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
452 return 0;
453
454 inet = inet_sk(sk);
455 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
456 IPPROTO_UDP, 0);
457
458 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
459 !csum_fold(csum_add(psum, skb->csum)))
460 return 0;
461
462 skb->csum = psum;
463
464 return __skb_checksum_complete(skb);
465}
466
James Chapmanf7faffa2010-04-02 06:18:49 +0000467/* Do receive processing of L2TP data frames. We handle both L2TPv2
468 * and L2TPv3 data frames here.
469 *
470 * L2TPv2 Data Message Header
471 *
472 * 0 1 2 3
473 * 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
474 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
475 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
476 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
477 * | Tunnel ID | Session ID |
478 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
479 * | Ns (opt) | Nr (opt) |
480 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
481 * | Offset Size (opt) | Offset pad... (opt)
482 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
483 *
484 * Data frames are marked by T=0. All other fields are the same as
485 * those in L2TP control frames.
486 *
487 * L2TPv3 Data Message Header
488 *
489 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
490 * | L2TP Session Header |
491 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
492 * | L2-Specific Sublayer |
493 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
494 * | Tunnel Payload ...
495 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
496 *
497 * L2TPv3 Session Header Over IP
498 *
499 * 0 1 2 3
500 * 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
501 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
502 * | Session ID |
503 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
504 * | Cookie (optional, maximum 64 bits)...
505 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
506 * |
507 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
508 *
509 * L2TPv3 L2-Specific Sublayer Format
510 *
511 * 0 1 2 3
512 * 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
513 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
514 * |x|S|x|x|x|x|x|x| Sequence Number |
515 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
516 *
517 * Cookie value, sublayer format and offset (pad) are negotiated with
518 * the peer when the session is set up. Unlike L2TPv2, we do not need
519 * to parse the packet header to determine if optional fields are
520 * present.
521 *
522 * Caller must already have parsed the frame and determined that it is
523 * a data (not control) frame before coming here. Fields up to the
524 * session-id have already been parsed and ptr points to the data
525 * after the session-id.
James Chapmanfd558d12010-04-02 06:18:33 +0000526 */
James Chapmanf7faffa2010-04-02 06:18:49 +0000527void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
528 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
529 int length, int (*payload_hook)(struct sk_buff *skb))
James Chapmanfd558d12010-04-02 06:18:33 +0000530{
James Chapmanf7faffa2010-04-02 06:18:49 +0000531 struct l2tp_tunnel *tunnel = session->tunnel;
James Chapmanfd558d12010-04-02 06:18:33 +0000532 int offset;
James Chapmanf7faffa2010-04-02 06:18:49 +0000533 u32 ns, nr;
James Chapmanfd558d12010-04-02 06:18:33 +0000534
535 /* The ref count is increased since we now hold a pointer to
536 * the session. Take care to decrement the refcnt when exiting
537 * this function from now on...
538 */
539 l2tp_session_inc_refcount(session);
540 if (session->ref)
541 (*session->ref)(session);
542
James Chapmanf7faffa2010-04-02 06:18:49 +0000543 /* Parse and check optional cookie */
544 if (session->peer_cookie_len > 0) {
545 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
546 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
547 "%s: cookie mismatch (%u/%u). Discarding.\n",
548 tunnel->name, tunnel->tunnel_id, session->session_id);
549 session->stats.rx_cookie_discards++;
550 goto discard;
551 }
552 ptr += session->peer_cookie_len;
553 }
554
James Chapmanfd558d12010-04-02 06:18:33 +0000555 /* Handle the optional sequence numbers. Sequence numbers are
556 * in different places for L2TPv2 and L2TPv3.
557 *
558 * If we are the LAC, enable/disable sequence numbers under
559 * the control of the LNS. If no sequence numbers present but
560 * we were expecting them, discard frame.
561 */
562 ns = nr = 0;
563 L2TP_SKB_CB(skb)->has_seq = 0;
James Chapmanf7faffa2010-04-02 06:18:49 +0000564 if (tunnel->version == L2TP_HDR_VER_2) {
565 if (hdrflags & L2TP_HDRFLAG_S) {
566 ns = ntohs(*(__be16 *) ptr);
567 ptr += 2;
568 nr = ntohs(*(__be16 *) ptr);
569 ptr += 2;
James Chapmanfd558d12010-04-02 06:18:33 +0000570
James Chapmanf7faffa2010-04-02 06:18:49 +0000571 /* Store L2TP info in the skb */
572 L2TP_SKB_CB(skb)->ns = ns;
573 L2TP_SKB_CB(skb)->has_seq = 1;
James Chapmanfd558d12010-04-02 06:18:33 +0000574
James Chapmanf7faffa2010-04-02 06:18:49 +0000575 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
576 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
577 session->name, ns, nr, session->nr);
578 }
579 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
580 u32 l2h = ntohl(*(__be32 *) ptr);
581
582 if (l2h & 0x40000000) {
583 ns = l2h & 0x00ffffff;
584
585 /* Store L2TP info in the skb */
586 L2TP_SKB_CB(skb)->ns = ns;
587 L2TP_SKB_CB(skb)->has_seq = 1;
588
589 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
590 "%s: recv data ns=%u, session nr=%u\n",
591 session->name, ns, session->nr);
592 }
James Chapmanfd558d12010-04-02 06:18:33 +0000593 }
594
James Chapmanf7faffa2010-04-02 06:18:49 +0000595 /* Advance past L2-specific header, if present */
596 ptr += session->l2specific_len;
597
James Chapmanfd558d12010-04-02 06:18:33 +0000598 if (L2TP_SKB_CB(skb)->has_seq) {
599 /* Received a packet with sequence numbers. If we're the LNS,
600 * check if we sre sending sequence numbers and if not,
601 * configure it so.
602 */
603 if ((!session->lns_mode) && (!session->send_seq)) {
604 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
605 "%s: requested to enable seq numbers by LNS\n",
606 session->name);
607 session->send_seq = -1;
James Chapmanf7faffa2010-04-02 06:18:49 +0000608 l2tp_session_set_header_len(session, tunnel->version);
James Chapmanfd558d12010-04-02 06:18:33 +0000609 }
610 } else {
611 /* No sequence numbers.
612 * If user has configured mandatory sequence numbers, discard.
613 */
614 if (session->recv_seq) {
615 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
616 "%s: recv data has no seq numbers when required. "
617 "Discarding\n", session->name);
618 session->stats.rx_seq_discards++;
619 goto discard;
620 }
621
622 /* If we're the LAC and we're sending sequence numbers, the
623 * LNS has requested that we no longer send sequence numbers.
624 * If we're the LNS and we're sending sequence numbers, the
625 * LAC is broken. Discard the frame.
626 */
627 if ((!session->lns_mode) && (session->send_seq)) {
628 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
629 "%s: requested to disable seq numbers by LNS\n",
630 session->name);
631 session->send_seq = 0;
James Chapmanf7faffa2010-04-02 06:18:49 +0000632 l2tp_session_set_header_len(session, tunnel->version);
James Chapmanfd558d12010-04-02 06:18:33 +0000633 } else if (session->send_seq) {
634 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
635 "%s: recv data has no seq numbers when required. "
636 "Discarding\n", session->name);
637 session->stats.rx_seq_discards++;
638 goto discard;
639 }
640 }
641
James Chapmanf7faffa2010-04-02 06:18:49 +0000642 /* Session data offset is handled differently for L2TPv2 and
643 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
644 * the header. For L2TPv3, the offset is negotiated using AVPs
645 * in the session setup control protocol.
646 */
647 if (tunnel->version == L2TP_HDR_VER_2) {
648 /* If offset bit set, skip it. */
649 if (hdrflags & L2TP_HDRFLAG_O) {
650 offset = ntohs(*(__be16 *)ptr);
651 ptr += 2 + offset;
652 }
653 } else
654 ptr += session->offset;
James Chapmanfd558d12010-04-02 06:18:33 +0000655
656 offset = ptr - optr;
657 if (!pskb_may_pull(skb, offset))
658 goto discard;
659
660 __skb_pull(skb, offset);
661
662 /* If caller wants to process the payload before we queue the
663 * packet, do so now.
664 */
665 if (payload_hook)
666 if ((*payload_hook)(skb))
667 goto discard;
668
669 /* Prepare skb for adding to the session's reorder_q. Hold
670 * packets for max reorder_timeout or 1 second if not
671 * reordering.
672 */
673 L2TP_SKB_CB(skb)->length = length;
674 L2TP_SKB_CB(skb)->expires = jiffies +
675 (session->reorder_timeout ? session->reorder_timeout : HZ);
676
677 /* Add packet to the session's receive queue. Reordering is done here, if
678 * enabled. Saved L2TP protocol info is stored in skb->sb[].
679 */
680 if (L2TP_SKB_CB(skb)->has_seq) {
681 if (session->reorder_timeout != 0) {
682 /* Packet reordering enabled. Add skb to session's
683 * reorder queue, in order of ns.
684 */
685 l2tp_recv_queue_skb(session, skb);
686 } else {
687 /* Packet reordering disabled. Discard out-of-sequence
688 * packets
689 */
690 if (L2TP_SKB_CB(skb)->ns != session->nr) {
691 session->stats.rx_seq_discards++;
692 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
James Chapmanf7faffa2010-04-02 06:18:49 +0000693 "%s: oos pkt %u len %d discarded, "
694 "waiting for %u, reorder_q_len=%d\n",
James Chapmanfd558d12010-04-02 06:18:33 +0000695 session->name, L2TP_SKB_CB(skb)->ns,
696 L2TP_SKB_CB(skb)->length, session->nr,
697 skb_queue_len(&session->reorder_q));
698 goto discard;
699 }
700 skb_queue_tail(&session->reorder_q, skb);
701 }
702 } else {
703 /* No sequence numbers. Add the skb to the tail of the
704 * reorder queue. This ensures that it will be
705 * delivered after all previous sequenced skbs.
706 */
707 skb_queue_tail(&session->reorder_q, skb);
708 }
709
710 /* Try to dequeue as many skbs from reorder_q as we can. */
711 l2tp_recv_dequeue(session);
712
713 l2tp_session_dec_refcount(session);
714
James Chapmanf7faffa2010-04-02 06:18:49 +0000715 return;
James Chapmanfd558d12010-04-02 06:18:33 +0000716
717discard:
718 session->stats.rx_errors++;
719 kfree_skb(skb);
720
721 if (session->deref)
722 (*session->deref)(session);
723
724 l2tp_session_dec_refcount(session);
James Chapmanf7faffa2010-04-02 06:18:49 +0000725}
726EXPORT_SYMBOL(l2tp_recv_common);
727
728/* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
729 * here. The skb is not on a list when we get here.
730 * Returns 0 if the packet was a data packet and was successfully passed on.
731 * Returns 1 if the packet was not a good data packet and could not be
732 * forwarded. All such packets are passed up to userspace to deal with.
733 */
stephen hemmingerfc130842010-10-21 07:50:46 +0000734static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
735 int (*payload_hook)(struct sk_buff *skb))
James Chapmanf7faffa2010-04-02 06:18:49 +0000736{
737 struct l2tp_session *session = NULL;
738 unsigned char *ptr, *optr;
739 u16 hdrflags;
740 u32 tunnel_id, session_id;
741 int offset;
742 u16 version;
743 int length;
744
745 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
746 goto discard_bad_csum;
747
748 /* UDP always verifies the packet length. */
749 __skb_pull(skb, sizeof(struct udphdr));
750
751 /* Short packet? */
752 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
753 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
754 "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
755 goto error;
756 }
757
758 /* Point to L2TP header */
759 optr = ptr = skb->data;
760
761 /* Trace packet contents, if enabled */
762 if (tunnel->debug & L2TP_MSG_DATA) {
763 length = min(32u, skb->len);
764 if (!pskb_may_pull(skb, length))
765 goto error;
766
767 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
768
769 offset = 0;
770 do {
771 printk(" %02X", ptr[offset]);
772 } while (++offset < length);
773
774 printk("\n");
775 }
776
777 /* Get L2TP header flags */
778 hdrflags = ntohs(*(__be16 *) ptr);
779
780 /* Check protocol version */
781 version = hdrflags & L2TP_HDR_VER_MASK;
782 if (version != tunnel->version) {
783 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
784 "%s: recv protocol version mismatch: got %d expected %d\n",
785 tunnel->name, version, tunnel->version);
786 goto error;
787 }
788
789 /* Get length of L2TP packet */
790 length = skb->len;
791
792 /* If type is control packet, it is handled by userspace. */
793 if (hdrflags & L2TP_HDRFLAG_T) {
794 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
795 "%s: recv control packet, len=%d\n", tunnel->name, length);
796 goto error;
797 }
798
799 /* Skip flags */
800 ptr += 2;
801
802 if (tunnel->version == L2TP_HDR_VER_2) {
803 /* If length is present, skip it */
804 if (hdrflags & L2TP_HDRFLAG_L)
805 ptr += 2;
806
807 /* Extract tunnel and session ID */
808 tunnel_id = ntohs(*(__be16 *) ptr);
809 ptr += 2;
810 session_id = ntohs(*(__be16 *) ptr);
811 ptr += 2;
812 } else {
813 ptr += 2; /* skip reserved bits */
814 tunnel_id = tunnel->tunnel_id;
815 session_id = ntohl(*(__be32 *) ptr);
816 ptr += 4;
817 }
818
819 /* Find the session context */
820 session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id);
James Chapman309795f2010-04-02 06:19:10 +0000821 if (!session || !session->recv_skb) {
James Chapmanf7faffa2010-04-02 06:18:49 +0000822 /* Not found? Pass to userspace to deal with */
823 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
824 "%s: no session found (%u/%u). Passing up.\n",
825 tunnel->name, tunnel_id, session_id);
826 goto error;
827 }
828
829 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
James Chapmanfd558d12010-04-02 06:18:33 +0000830
831 return 0;
832
833discard_bad_csum:
834 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
835 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
836 tunnel->stats.rx_errors++;
837 kfree_skb(skb);
838
839 return 0;
840
841error:
842 /* Put UDP header back */
843 __skb_push(skb, sizeof(struct udphdr));
844
845 return 1;
846}
847EXPORT_SYMBOL_GPL(l2tp_udp_recv_core);
848
849/* UDP encapsulation receive handler. See net/ipv4/udp.c.
850 * Return codes:
851 * 0 : success.
852 * <0: error
853 * >0: skb should be passed up to userspace as UDP.
854 */
855int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
856{
857 struct l2tp_tunnel *tunnel;
858
859 tunnel = l2tp_sock_to_tunnel(sk);
860 if (tunnel == NULL)
861 goto pass_up;
862
863 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
864 "%s: received %d bytes\n", tunnel->name, skb->len);
865
866 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
867 goto pass_up_put;
868
869 sock_put(sk);
870 return 0;
871
872pass_up_put:
873 sock_put(sk);
874pass_up:
875 return 1;
876}
877EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
878
879/************************************************************************
880 * Transmit handling
881 ***********************************************************************/
882
883/* Build an L2TP header for the session into the buffer provided.
884 */
James Chapmanf7faffa2010-04-02 06:18:49 +0000885static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
James Chapmanfd558d12010-04-02 06:18:33 +0000886{
James Chapmanf7faffa2010-04-02 06:18:49 +0000887 struct l2tp_tunnel *tunnel = session->tunnel;
James Chapmanfd558d12010-04-02 06:18:33 +0000888 __be16 *bufp = buf;
James Chapmanf7faffa2010-04-02 06:18:49 +0000889 __be16 *optr = buf;
James Chapmanfd558d12010-04-02 06:18:33 +0000890 u16 flags = L2TP_HDR_VER_2;
891 u32 tunnel_id = tunnel->peer_tunnel_id;
892 u32 session_id = session->peer_session_id;
893
894 if (session->send_seq)
895 flags |= L2TP_HDRFLAG_S;
896
897 /* Setup L2TP header. */
898 *bufp++ = htons(flags);
899 *bufp++ = htons(tunnel_id);
900 *bufp++ = htons(session_id);
901 if (session->send_seq) {
902 *bufp++ = htons(session->ns);
903 *bufp++ = 0;
904 session->ns++;
James Chapmanf7faffa2010-04-02 06:18:49 +0000905 session->ns &= 0xffff;
James Chapmanfd558d12010-04-02 06:18:33 +0000906 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
James Chapmanf7faffa2010-04-02 06:18:49 +0000907 "%s: updated ns to %u\n", session->name, session->ns);
James Chapmanfd558d12010-04-02 06:18:33 +0000908 }
James Chapmanf7faffa2010-04-02 06:18:49 +0000909
910 return bufp - optr;
James Chapmanfd558d12010-04-02 06:18:33 +0000911}
912
James Chapmanf7faffa2010-04-02 06:18:49 +0000913static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
James Chapmanfd558d12010-04-02 06:18:33 +0000914{
James Chapman0d767512010-04-02 06:19:00 +0000915 struct l2tp_tunnel *tunnel = session->tunnel;
James Chapmanf7faffa2010-04-02 06:18:49 +0000916 char *bufp = buf;
917 char *optr = bufp;
James Chapmanfd558d12010-04-02 06:18:33 +0000918
James Chapman0d767512010-04-02 06:19:00 +0000919 /* Setup L2TP header. The header differs slightly for UDP and
920 * IP encapsulations. For UDP, there is 4 bytes of flags.
921 */
922 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
923 u16 flags = L2TP_HDR_VER_3;
924 *((__be16 *) bufp) = htons(flags);
925 bufp += 2;
926 *((__be16 *) bufp) = 0;
927 bufp += 2;
928 }
929
James Chapmanf7faffa2010-04-02 06:18:49 +0000930 *((__be32 *) bufp) = htonl(session->peer_session_id);
931 bufp += 4;
932 if (session->cookie_len) {
933 memcpy(bufp, &session->cookie[0], session->cookie_len);
934 bufp += session->cookie_len;
935 }
936 if (session->l2specific_len) {
937 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
938 u32 l2h = 0;
939 if (session->send_seq) {
940 l2h = 0x40000000 | session->ns;
941 session->ns++;
942 session->ns &= 0xffffff;
943 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
944 "%s: updated ns to %u\n", session->name, session->ns);
945 }
946
947 *((__be32 *) bufp) = htonl(l2h);
948 }
949 bufp += session->l2specific_len;
950 }
951 if (session->offset)
952 bufp += session->offset;
953
954 return bufp - optr;
James Chapmanfd558d12010-04-02 06:18:33 +0000955}
James Chapmanfd558d12010-04-02 06:18:33 +0000956
stephen hemmingerfc130842010-10-21 07:50:46 +0000957static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
958 size_t data_len)
James Chapmanfd558d12010-04-02 06:18:33 +0000959{
960 struct l2tp_tunnel *tunnel = session->tunnel;
961 unsigned int len = skb->len;
962 int error;
963
964 /* Debug */
965 if (session->send_seq)
966 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
James Chapmanf7faffa2010-04-02 06:18:49 +0000967 "%s: send %Zd bytes, ns=%u\n", session->name,
James Chapmanfd558d12010-04-02 06:18:33 +0000968 data_len, session->ns - 1);
969 else
970 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
971 "%s: send %Zd bytes\n", session->name, data_len);
972
973 if (session->debug & L2TP_MSG_DATA) {
974 int i;
James Chapman0d767512010-04-02 06:19:00 +0000975 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
976 unsigned char *datap = skb->data + uhlen;
James Chapmanfd558d12010-04-02 06:18:33 +0000977
978 printk(KERN_DEBUG "%s: xmit:", session->name);
James Chapman0d767512010-04-02 06:19:00 +0000979 for (i = 0; i < (len - uhlen); i++) {
James Chapmanfd558d12010-04-02 06:18:33 +0000980 printk(" %02X", *datap++);
981 if (i == 31) {
982 printk(" ...");
983 break;
984 }
985 }
986 printk("\n");
987 }
988
989 /* Queue the packet to IP for output */
Shan Wei4e15ed42010-04-15 16:43:08 +0000990 skb->local_df = 1;
991 error = ip_queue_xmit(skb);
James Chapmanfd558d12010-04-02 06:18:33 +0000992
993 /* Update stats */
994 if (error >= 0) {
995 tunnel->stats.tx_packets++;
996 tunnel->stats.tx_bytes += len;
997 session->stats.tx_packets++;
998 session->stats.tx_bytes += len;
999 } else {
1000 tunnel->stats.tx_errors++;
1001 session->stats.tx_errors++;
1002 }
1003
1004 return 0;
1005}
1006EXPORT_SYMBOL_GPL(l2tp_xmit_core);
1007
1008/* Automatically called when the skb is freed.
1009 */
1010static void l2tp_sock_wfree(struct sk_buff *skb)
1011{
1012 sock_put(skb->sk);
1013}
1014
1015/* For data skbs that we transmit, we associate with the tunnel socket
1016 * but don't do accounting.
1017 */
1018static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1019{
1020 sock_hold(sk);
1021 skb->sk = sk;
1022 skb->destructor = l2tp_sock_wfree;
1023}
1024
1025/* If caller requires the skb to have a ppp header, the header must be
1026 * inserted in the skb data before calling this function.
1027 */
1028int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1029{
1030 int data_len = skb->len;
James Chapman0d767512010-04-02 06:19:00 +00001031 struct l2tp_tunnel *tunnel = session->tunnel;
1032 struct sock *sk = tunnel->sock;
James Chapmanfd558d12010-04-02 06:18:33 +00001033 struct udphdr *uh;
James Chapmanfd558d12010-04-02 06:18:33 +00001034 struct inet_sock *inet;
1035 __wsum csum;
1036 int old_headroom;
1037 int new_headroom;
1038 int headroom;
James Chapman0d767512010-04-02 06:19:00 +00001039 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
1040 int udp_len;
James Chapmanfd558d12010-04-02 06:18:33 +00001041
1042 /* Check that there's enough headroom in the skb to insert IP,
1043 * UDP and L2TP headers. If not enough, expand it to
1044 * make room. Adjust truesize.
1045 */
1046 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
James Chapman0d767512010-04-02 06:19:00 +00001047 uhlen + hdr_len;
James Chapmanfd558d12010-04-02 06:18:33 +00001048 old_headroom = skb_headroom(skb);
1049 if (skb_cow_head(skb, headroom))
1050 goto abort;
1051
1052 new_headroom = skb_headroom(skb);
1053 skb_orphan(skb);
1054 skb->truesize += new_headroom - old_headroom;
1055
1056 /* Setup L2TP header */
James Chapmanf7faffa2010-04-02 06:18:49 +00001057 session->build_header(session, __skb_push(skb, hdr_len));
James Chapmanfd558d12010-04-02 06:18:33 +00001058
James Chapman0d767512010-04-02 06:19:00 +00001059 /* Reset skb netfilter state */
James Chapmanfd558d12010-04-02 06:18:33 +00001060 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1061 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1062 IPSKB_REROUTED);
1063 nf_reset(skb);
1064
1065 /* Get routing info from the tunnel socket */
1066 skb_dst_drop(skb);
1067 skb_dst_set(skb, dst_clone(__sk_dst_get(sk)));
James Chapmanfd558d12010-04-02 06:18:33 +00001068
James Chapman0d767512010-04-02 06:19:00 +00001069 switch (tunnel->encap) {
1070 case L2TP_ENCAPTYPE_UDP:
1071 /* Setup UDP header */
1072 inet = inet_sk(sk);
1073 __skb_push(skb, sizeof(*uh));
1074 skb_reset_transport_header(skb);
1075 uh = udp_hdr(skb);
1076 uh->source = inet->inet_sport;
1077 uh->dest = inet->inet_dport;
1078 udp_len = uhlen + hdr_len + data_len;
1079 uh->len = htons(udp_len);
1080 uh->check = 0;
1081
1082 /* Calculate UDP checksum if configured to do so */
1083 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1084 skb->ip_summed = CHECKSUM_NONE;
1085 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1086 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1087 skb->ip_summed = CHECKSUM_COMPLETE;
1088 csum = skb_checksum(skb, 0, udp_len, 0);
1089 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1090 inet->inet_daddr,
1091 udp_len, IPPROTO_UDP, csum);
1092 if (uh->check == 0)
1093 uh->check = CSUM_MANGLED_0;
1094 } else {
1095 skb->ip_summed = CHECKSUM_PARTIAL;
1096 skb->csum_start = skb_transport_header(skb) - skb->head;
1097 skb->csum_offset = offsetof(struct udphdr, check);
1098 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1099 inet->inet_daddr,
1100 udp_len, IPPROTO_UDP, 0);
1101 }
1102 break;
1103
1104 case L2TP_ENCAPTYPE_IP:
1105 break;
James Chapmanfd558d12010-04-02 06:18:33 +00001106 }
1107
James Chapman0d767512010-04-02 06:19:00 +00001108 l2tp_skb_set_owner_w(skb, sk);
1109
James Chapmanfd558d12010-04-02 06:18:33 +00001110 l2tp_xmit_core(session, skb, data_len);
1111
1112abort:
1113 return 0;
1114}
1115EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1116
1117/*****************************************************************************
1118 * Tinnel and session create/destroy.
1119 *****************************************************************************/
1120
1121/* Tunnel socket destruct hook.
1122 * The tunnel context is deleted only when all session sockets have been
1123 * closed.
1124 */
stephen hemmingerfc130842010-10-21 07:50:46 +00001125static void l2tp_tunnel_destruct(struct sock *sk)
James Chapmanfd558d12010-04-02 06:18:33 +00001126{
1127 struct l2tp_tunnel *tunnel;
1128
1129 tunnel = sk->sk_user_data;
1130 if (tunnel == NULL)
1131 goto end;
1132
1133 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1134 "%s: closing...\n", tunnel->name);
1135
1136 /* Close all sessions */
1137 l2tp_tunnel_closeall(tunnel);
1138
James Chapman0d767512010-04-02 06:19:00 +00001139 switch (tunnel->encap) {
1140 case L2TP_ENCAPTYPE_UDP:
1141 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1142 (udp_sk(sk))->encap_type = 0;
1143 (udp_sk(sk))->encap_rcv = NULL;
1144 break;
1145 case L2TP_ENCAPTYPE_IP:
1146 break;
1147 }
James Chapmanfd558d12010-04-02 06:18:33 +00001148
1149 /* Remove hooks into tunnel socket */
1150 tunnel->sock = NULL;
1151 sk->sk_destruct = tunnel->old_sk_destruct;
1152 sk->sk_user_data = NULL;
1153
1154 /* Call the original destructor */
1155 if (sk->sk_destruct)
1156 (*sk->sk_destruct)(sk);
1157
1158 /* We're finished with the socket */
1159 l2tp_tunnel_dec_refcount(tunnel);
1160
1161end:
1162 return;
1163}
James Chapmanfd558d12010-04-02 06:18:33 +00001164
1165/* When the tunnel is closed, all the attached sessions need to go too.
1166 */
stephen hemmingerfc130842010-10-21 07:50:46 +00001167static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
James Chapmanfd558d12010-04-02 06:18:33 +00001168{
1169 int hash;
1170 struct hlist_node *walk;
1171 struct hlist_node *tmp;
1172 struct l2tp_session *session;
1173
1174 BUG_ON(tunnel == NULL);
1175
1176 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1177 "%s: closing all sessions...\n", tunnel->name);
1178
1179 write_lock_bh(&tunnel->hlist_lock);
1180 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1181again:
1182 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1183 session = hlist_entry(walk, struct l2tp_session, hlist);
1184
1185 PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO,
1186 "%s: closing session\n", session->name);
1187
1188 hlist_del_init(&session->hlist);
1189
1190 /* Since we should hold the sock lock while
1191 * doing any unbinding, we need to release the
1192 * lock we're holding before taking that lock.
1193 * Hold a reference to the sock so it doesn't
1194 * disappear as we're jumping between locks.
1195 */
1196 if (session->ref != NULL)
1197 (*session->ref)(session);
1198
1199 write_unlock_bh(&tunnel->hlist_lock);
1200
James Chapmanf7faffa2010-04-02 06:18:49 +00001201 if (tunnel->version != L2TP_HDR_VER_2) {
1202 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1203
James Chapmane02d4942010-04-02 06:19:16 +00001204 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1205 hlist_del_init_rcu(&session->global_hlist);
1206 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1207 synchronize_rcu();
James Chapmanf7faffa2010-04-02 06:18:49 +00001208 }
1209
James Chapmanfd558d12010-04-02 06:18:33 +00001210 if (session->session_close != NULL)
1211 (*session->session_close)(session);
1212
1213 if (session->deref != NULL)
1214 (*session->deref)(session);
1215
1216 write_lock_bh(&tunnel->hlist_lock);
1217
1218 /* Now restart from the beginning of this hash
1219 * chain. We always remove a session from the
1220 * list so we are guaranteed to make forward
1221 * progress.
1222 */
1223 goto again;
1224 }
1225 }
1226 write_unlock_bh(&tunnel->hlist_lock);
1227}
1228EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall);
1229
1230/* Really kill the tunnel.
1231 * Come here only when all sessions have been cleared from the tunnel.
1232 */
stephen hemmingerfc130842010-10-21 07:50:46 +00001233static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
James Chapmanfd558d12010-04-02 06:18:33 +00001234{
1235 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1236
1237 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1238 BUG_ON(tunnel->sock != NULL);
1239
1240 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1241 "%s: free...\n", tunnel->name);
1242
1243 /* Remove from tunnel list */
James Chapmane02d4942010-04-02 06:19:16 +00001244 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1245 list_del_rcu(&tunnel->list);
1246 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1247 synchronize_rcu();
James Chapmanfd558d12010-04-02 06:18:33 +00001248
1249 atomic_dec(&l2tp_tunnel_count);
1250 kfree(tunnel);
1251}
James Chapmanfd558d12010-04-02 06:18:33 +00001252
James Chapman789a4a22010-04-02 06:19:40 +00001253/* Create a socket for the tunnel, if one isn't set up by
1254 * userspace. This is used for static tunnels where there is no
1255 * managing L2TP daemon.
1256 */
1257static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1258{
1259 int err = -EINVAL;
1260 struct sockaddr_in udp_addr;
1261 struct sockaddr_l2tpip ip_addr;
Eric Dumazet7bddd0d2010-04-04 01:02:46 -07001262 struct socket *sock = NULL;
James Chapman789a4a22010-04-02 06:19:40 +00001263
1264 switch (cfg->encap) {
1265 case L2TP_ENCAPTYPE_UDP:
1266 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1267 if (err < 0)
1268 goto out;
1269
1270 sock = *sockp;
1271
1272 memset(&udp_addr, 0, sizeof(udp_addr));
1273 udp_addr.sin_family = AF_INET;
1274 udp_addr.sin_addr = cfg->local_ip;
1275 udp_addr.sin_port = htons(cfg->local_udp_port);
1276 err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr));
1277 if (err < 0)
1278 goto out;
1279
1280 udp_addr.sin_family = AF_INET;
1281 udp_addr.sin_addr = cfg->peer_ip;
1282 udp_addr.sin_port = htons(cfg->peer_udp_port);
1283 err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0);
1284 if (err < 0)
1285 goto out;
1286
1287 if (!cfg->use_udp_checksums)
1288 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1289
1290 break;
1291
1292 case L2TP_ENCAPTYPE_IP:
1293 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
1294 if (err < 0)
1295 goto out;
1296
1297 sock = *sockp;
1298
1299 memset(&ip_addr, 0, sizeof(ip_addr));
1300 ip_addr.l2tp_family = AF_INET;
1301 ip_addr.l2tp_addr = cfg->local_ip;
1302 ip_addr.l2tp_conn_id = tunnel_id;
1303 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr));
1304 if (err < 0)
1305 goto out;
1306
1307 ip_addr.l2tp_family = AF_INET;
1308 ip_addr.l2tp_addr = cfg->peer_ip;
1309 ip_addr.l2tp_conn_id = peer_tunnel_id;
1310 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0);
1311 if (err < 0)
1312 goto out;
1313
1314 break;
1315
1316 default:
1317 goto out;
1318 }
1319
1320out:
1321 if ((err < 0) && sock) {
1322 sock_release(sock);
1323 *sockp = NULL;
1324 }
1325
1326 return err;
1327}
1328
James Chapmanfd558d12010-04-02 06:18:33 +00001329int 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)
1330{
1331 struct l2tp_tunnel *tunnel = NULL;
1332 int err;
1333 struct socket *sock = NULL;
1334 struct sock *sk = NULL;
1335 struct l2tp_net *pn;
James Chapman0d767512010-04-02 06:19:00 +00001336 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
James Chapmanfd558d12010-04-02 06:18:33 +00001337
1338 /* Get the tunnel socket from the fd, which was opened by
James Chapman789a4a22010-04-02 06:19:40 +00001339 * the userspace L2TP daemon. If not specified, create a
1340 * kernel socket.
James Chapmanfd558d12010-04-02 06:18:33 +00001341 */
James Chapman789a4a22010-04-02 06:19:40 +00001342 if (fd < 0) {
1343 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1344 if (err < 0)
1345 goto err;
1346 } else {
1347 err = -EBADF;
1348 sock = sockfd_lookup(fd, &err);
1349 if (!sock) {
1350 printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1351 tunnel_id, fd, err);
1352 goto err;
1353 }
James Chapmanfd558d12010-04-02 06:18:33 +00001354 }
1355
1356 sk = sock->sk;
1357
James Chapman0d767512010-04-02 06:19:00 +00001358 if (cfg != NULL)
1359 encap = cfg->encap;
1360
James Chapmanfd558d12010-04-02 06:18:33 +00001361 /* Quick sanity checks */
James Chapman0d767512010-04-02 06:19:00 +00001362 switch (encap) {
1363 case L2TP_ENCAPTYPE_UDP:
1364 err = -EPROTONOSUPPORT;
1365 if (sk->sk_protocol != IPPROTO_UDP) {
1366 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1367 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1368 goto err;
1369 }
1370 break;
1371 case L2TP_ENCAPTYPE_IP:
1372 err = -EPROTONOSUPPORT;
1373 if (sk->sk_protocol != IPPROTO_L2TP) {
1374 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1375 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1376 goto err;
1377 }
1378 break;
James Chapmanfd558d12010-04-02 06:18:33 +00001379 }
1380
1381 /* Check if this socket has already been prepped */
1382 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1383 if (tunnel != NULL) {
1384 /* This socket has already been prepped */
1385 err = -EBUSY;
1386 goto err;
1387 }
1388
James Chapmanfd558d12010-04-02 06:18:33 +00001389 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1390 if (tunnel == NULL) {
1391 err = -ENOMEM;
1392 goto err;
1393 }
1394
1395 tunnel->version = version;
1396 tunnel->tunnel_id = tunnel_id;
1397 tunnel->peer_tunnel_id = peer_tunnel_id;
1398 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1399
1400 tunnel->magic = L2TP_TUNNEL_MAGIC;
1401 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1402 rwlock_init(&tunnel->hlist_lock);
1403
1404 /* The net we belong to */
1405 tunnel->l2tp_net = net;
1406 pn = l2tp_pernet(net);
1407
James Chapman0d767512010-04-02 06:19:00 +00001408 if (cfg != NULL)
James Chapmanfd558d12010-04-02 06:18:33 +00001409 tunnel->debug = cfg->debug;
1410
1411 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
James Chapman0d767512010-04-02 06:19:00 +00001412 tunnel->encap = encap;
1413 if (encap == L2TP_ENCAPTYPE_UDP) {
1414 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1415 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1416 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1417 }
James Chapmanfd558d12010-04-02 06:18:33 +00001418
1419 sk->sk_user_data = tunnel;
1420
1421 /* Hook on the tunnel socket destructor so that we can cleanup
1422 * if the tunnel socket goes away.
1423 */
1424 tunnel->old_sk_destruct = sk->sk_destruct;
1425 sk->sk_destruct = &l2tp_tunnel_destruct;
1426 tunnel->sock = sk;
1427 sk->sk_allocation = GFP_ATOMIC;
1428
1429 /* Add tunnel to our list */
1430 INIT_LIST_HEAD(&tunnel->list);
James Chapmane02d4942010-04-02 06:19:16 +00001431 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1432 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1433 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1434 synchronize_rcu();
James Chapmanfd558d12010-04-02 06:18:33 +00001435 atomic_inc(&l2tp_tunnel_count);
1436
1437 /* Bump the reference count. The tunnel context is deleted
1438 * only when this drops to zero.
1439 */
1440 l2tp_tunnel_inc_refcount(tunnel);
1441
1442 err = 0;
1443err:
1444 if (tunnelp)
1445 *tunnelp = tunnel;
1446
James Chapman789a4a22010-04-02 06:19:40 +00001447 /* If tunnel's socket was created by the kernel, it doesn't
1448 * have a file.
1449 */
1450 if (sock && sock->file)
James Chapmanfd558d12010-04-02 06:18:33 +00001451 sockfd_put(sock);
1452
1453 return err;
1454}
1455EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1456
James Chapman309795f2010-04-02 06:19:10 +00001457/* This function is used by the netlink TUNNEL_DELETE command.
1458 */
1459int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1460{
1461 int err = 0;
James Chapman789a4a22010-04-02 06:19:40 +00001462 struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL;
James Chapman309795f2010-04-02 06:19:10 +00001463
1464 /* Force the tunnel socket to close. This will eventually
1465 * cause the tunnel to be deleted via the normal socket close
1466 * mechanisms when userspace closes the tunnel socket.
1467 */
James Chapman789a4a22010-04-02 06:19:40 +00001468 if (sock != NULL) {
1469 err = inet_shutdown(sock, 2);
1470
1471 /* If the tunnel's socket was created by the kernel,
1472 * close the socket here since the socket was not
1473 * created by userspace.
1474 */
1475 if (sock->file == NULL)
1476 err = inet_release(sock);
1477 }
James Chapman309795f2010-04-02 06:19:10 +00001478
1479 return err;
1480}
1481EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1482
James Chapmanfd558d12010-04-02 06:18:33 +00001483/* Really kill the session.
1484 */
1485void l2tp_session_free(struct l2tp_session *session)
1486{
1487 struct l2tp_tunnel *tunnel;
1488
1489 BUG_ON(atomic_read(&session->ref_count) != 0);
1490
1491 tunnel = session->tunnel;
1492 if (tunnel != NULL) {
1493 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1494
1495 /* Delete the session from the hash */
1496 write_lock_bh(&tunnel->hlist_lock);
1497 hlist_del_init(&session->hlist);
1498 write_unlock_bh(&tunnel->hlist_lock);
1499
James Chapmanf7faffa2010-04-02 06:18:49 +00001500 /* Unlink from the global hash if not L2TPv2 */
1501 if (tunnel->version != L2TP_HDR_VER_2) {
1502 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1503
James Chapmane02d4942010-04-02 06:19:16 +00001504 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1505 hlist_del_init_rcu(&session->global_hlist);
1506 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1507 synchronize_rcu();
James Chapmanf7faffa2010-04-02 06:18:49 +00001508 }
1509
James Chapmanfd558d12010-04-02 06:18:33 +00001510 if (session->session_id != 0)
1511 atomic_dec(&l2tp_session_count);
1512
1513 sock_put(tunnel->sock);
1514
1515 /* This will delete the tunnel context if this
1516 * is the last session on the tunnel.
1517 */
1518 session->tunnel = NULL;
1519 l2tp_tunnel_dec_refcount(tunnel);
1520 }
1521
1522 kfree(session);
1523
1524 return;
1525}
1526EXPORT_SYMBOL_GPL(l2tp_session_free);
1527
James Chapman309795f2010-04-02 06:19:10 +00001528/* This function is used by the netlink SESSION_DELETE command and by
1529 pseudowire modules.
1530 */
1531int l2tp_session_delete(struct l2tp_session *session)
1532{
1533 if (session->session_close != NULL)
1534 (*session->session_close)(session);
1535
1536 l2tp_session_dec_refcount(session);
1537
1538 return 0;
1539}
1540EXPORT_SYMBOL_GPL(l2tp_session_delete);
1541
1542
James Chapmanf7faffa2010-04-02 06:18:49 +00001543/* We come here whenever a session's send_seq, cookie_len or
1544 * l2specific_len parameters are set.
1545 */
stephen hemmingerfc130842010-10-21 07:50:46 +00001546static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
James Chapmanf7faffa2010-04-02 06:18:49 +00001547{
1548 if (version == L2TP_HDR_VER_2) {
1549 session->hdr_len = 6;
1550 if (session->send_seq)
1551 session->hdr_len += 4;
1552 } else {
James Chapman0d767512010-04-02 06:19:00 +00001553 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1554 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1555 session->hdr_len += 4;
James Chapmanf7faffa2010-04-02 06:18:49 +00001556 }
1557
1558}
James Chapmanf7faffa2010-04-02 06:18:49 +00001559
James Chapmanfd558d12010-04-02 06:18:33 +00001560struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
1561{
1562 struct l2tp_session *session;
1563
1564 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1565 if (session != NULL) {
1566 session->magic = L2TP_SESSION_MAGIC;
1567 session->tunnel = tunnel;
1568
1569 session->session_id = session_id;
1570 session->peer_session_id = peer_session_id;
James Chapmanf7faffa2010-04-02 06:18:49 +00001571 session->nr = 1;
James Chapmanfd558d12010-04-02 06:18:33 +00001572
1573 sprintf(&session->name[0], "sess %u/%u",
1574 tunnel->tunnel_id, session->session_id);
1575
1576 skb_queue_head_init(&session->reorder_q);
1577
1578 INIT_HLIST_NODE(&session->hlist);
James Chapmanf7faffa2010-04-02 06:18:49 +00001579 INIT_HLIST_NODE(&session->global_hlist);
James Chapmanfd558d12010-04-02 06:18:33 +00001580
1581 /* Inherit debug options from tunnel */
1582 session->debug = tunnel->debug;
1583
1584 if (cfg) {
James Chapmanf7faffa2010-04-02 06:18:49 +00001585 session->pwtype = cfg->pw_type;
James Chapmanfd558d12010-04-02 06:18:33 +00001586 session->debug = cfg->debug;
James Chapmanfd558d12010-04-02 06:18:33 +00001587 session->mtu = cfg->mtu;
1588 session->mru = cfg->mru;
1589 session->send_seq = cfg->send_seq;
1590 session->recv_seq = cfg->recv_seq;
1591 session->lns_mode = cfg->lns_mode;
James Chapmanf7faffa2010-04-02 06:18:49 +00001592 session->reorder_timeout = cfg->reorder_timeout;
1593 session->offset = cfg->offset;
1594 session->l2specific_type = cfg->l2specific_type;
1595 session->l2specific_len = cfg->l2specific_len;
1596 session->cookie_len = cfg->cookie_len;
1597 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1598 session->peer_cookie_len = cfg->peer_cookie_len;
1599 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
James Chapmanfd558d12010-04-02 06:18:33 +00001600 }
1601
James Chapmanf7faffa2010-04-02 06:18:49 +00001602 if (tunnel->version == L2TP_HDR_VER_2)
1603 session->build_header = l2tp_build_l2tpv2_header;
1604 else
1605 session->build_header = l2tp_build_l2tpv3_header;
1606
1607 l2tp_session_set_header_len(session, tunnel->version);
1608
James Chapmanfd558d12010-04-02 06:18:33 +00001609 /* Bump the reference count. The session context is deleted
1610 * only when this drops to zero.
1611 */
1612 l2tp_session_inc_refcount(session);
1613 l2tp_tunnel_inc_refcount(tunnel);
1614
1615 /* Ensure tunnel socket isn't deleted */
1616 sock_hold(tunnel->sock);
1617
1618 /* Add session to the tunnel's hash list */
1619 write_lock_bh(&tunnel->hlist_lock);
1620 hlist_add_head(&session->hlist,
1621 l2tp_session_id_hash(tunnel, session_id));
1622 write_unlock_bh(&tunnel->hlist_lock);
1623
James Chapmanf7faffa2010-04-02 06:18:49 +00001624 /* And to the global session list if L2TPv3 */
1625 if (tunnel->version != L2TP_HDR_VER_2) {
1626 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1627
James Chapmane02d4942010-04-02 06:19:16 +00001628 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1629 hlist_add_head_rcu(&session->global_hlist,
1630 l2tp_session_id_hash_2(pn, session_id));
1631 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1632 synchronize_rcu();
James Chapmanf7faffa2010-04-02 06:18:49 +00001633 }
1634
James Chapmanfd558d12010-04-02 06:18:33 +00001635 /* Ignore management session in session count value */
1636 if (session->session_id != 0)
1637 atomic_inc(&l2tp_session_count);
1638 }
1639
1640 return session;
1641}
1642EXPORT_SYMBOL_GPL(l2tp_session_create);
1643
1644/*****************************************************************************
1645 * Init and cleanup
1646 *****************************************************************************/
1647
1648static __net_init int l2tp_init_net(struct net *net)
1649{
Jiri Pirkoe773aaf2010-04-23 00:53:39 +00001650 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
James Chapmanf7faffa2010-04-02 06:18:49 +00001651 int hash;
James Chapmanfd558d12010-04-02 06:18:33 +00001652
James Chapmanfd558d12010-04-02 06:18:33 +00001653 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
James Chapmane02d4942010-04-02 06:19:16 +00001654 spin_lock_init(&pn->l2tp_tunnel_list_lock);
James Chapmanfd558d12010-04-02 06:18:33 +00001655
James Chapmanf7faffa2010-04-02 06:18:49 +00001656 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1657 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1658
James Chapmane02d4942010-04-02 06:19:16 +00001659 spin_lock_init(&pn->l2tp_session_hlist_lock);
James Chapmanf7faffa2010-04-02 06:18:49 +00001660
James Chapmanfd558d12010-04-02 06:18:33 +00001661 return 0;
James Chapmanfd558d12010-04-02 06:18:33 +00001662}
1663
1664static struct pernet_operations l2tp_net_ops = {
1665 .init = l2tp_init_net,
James Chapmanfd558d12010-04-02 06:18:33 +00001666 .id = &l2tp_net_id,
1667 .size = sizeof(struct l2tp_net),
1668};
1669
1670static int __init l2tp_init(void)
1671{
1672 int rc = 0;
1673
1674 rc = register_pernet_device(&l2tp_net_ops);
1675 if (rc)
1676 goto out;
1677
1678 printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION);
1679
1680out:
1681 return rc;
1682}
1683
1684static void __exit l2tp_exit(void)
1685{
1686 unregister_pernet_device(&l2tp_net_ops);
1687}
1688
1689module_init(l2tp_init);
1690module_exit(l2tp_exit);
1691
1692MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1693MODULE_DESCRIPTION("L2TP core");
1694MODULE_LICENSE("GPL");
1695MODULE_VERSION(L2TP_DRV_VERSION);
1696