blob: 89ff8c67943e8af26efe1bac80b306e297921ebd [file] [log] [blame]
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>
Arun Sharma600634972011-07-26 16:09:06 -070058#include <linux/atomic.h>
James Chapmanfd558d12010-04-02 06:18:33 +000059
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 */
Eric Dumazete2e210c2011-11-02 22:47:44 +0000400start:
James Chapmanfd558d12010-04-02 06:18:33 +0000401 spin_lock_bh(&session->reorder_q.lock);
402 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
403 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
404 session->stats.rx_seq_discards++;
405 session->stats.rx_errors++;
406 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
James Chapmanf7faffa2010-04-02 06:18:49 +0000407 "%s: oos pkt %u len %d discarded (too old), "
408 "waiting for %u, reorder_q_len=%d\n",
James Chapmanfd558d12010-04-02 06:18:33 +0000409 session->name, L2TP_SKB_CB(skb)->ns,
410 L2TP_SKB_CB(skb)->length, session->nr,
411 skb_queue_len(&session->reorder_q));
412 __skb_unlink(skb, &session->reorder_q);
413 kfree_skb(skb);
414 if (session->deref)
415 (*session->deref)(session);
416 continue;
417 }
418
419 if (L2TP_SKB_CB(skb)->has_seq) {
420 if (L2TP_SKB_CB(skb)->ns != session->nr) {
421 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
James Chapmanf7faffa2010-04-02 06:18:49 +0000422 "%s: holding oos pkt %u len %d, "
423 "waiting for %u, reorder_q_len=%d\n",
James Chapmanfd558d12010-04-02 06:18:33 +0000424 session->name, L2TP_SKB_CB(skb)->ns,
425 L2TP_SKB_CB(skb)->length, session->nr,
426 skb_queue_len(&session->reorder_q));
427 goto out;
428 }
429 }
430 __skb_unlink(skb, &session->reorder_q);
431
432 /* Process the skb. We release the queue lock while we
433 * do so to let other contexts process the queue.
434 */
435 spin_unlock_bh(&session->reorder_q.lock);
436 l2tp_recv_dequeue_skb(session, skb);
Eric Dumazete2e210c2011-11-02 22:47:44 +0000437 goto start;
James Chapmanfd558d12010-04-02 06:18:33 +0000438 }
439
440out:
441 spin_unlock_bh(&session->reorder_q.lock);
442}
443
444static inline int l2tp_verify_udp_checksum(struct sock *sk,
445 struct sk_buff *skb)
446{
447 struct udphdr *uh = udp_hdr(skb);
448 u16 ulen = ntohs(uh->len);
449 struct inet_sock *inet;
450 __wsum psum;
451
452 if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
453 return 0;
454
455 inet = inet_sk(sk);
456 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
457 IPPROTO_UDP, 0);
458
459 if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
460 !csum_fold(csum_add(psum, skb->csum)))
461 return 0;
462
463 skb->csum = psum;
464
465 return __skb_checksum_complete(skb);
466}
467
James Chapmanf7faffa2010-04-02 06:18:49 +0000468/* Do receive processing of L2TP data frames. We handle both L2TPv2
469 * and L2TPv3 data frames here.
470 *
471 * L2TPv2 Data Message Header
472 *
473 * 0 1 2 3
474 * 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
475 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
476 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
477 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
478 * | Tunnel ID | Session ID |
479 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
480 * | Ns (opt) | Nr (opt) |
481 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
482 * | Offset Size (opt) | Offset pad... (opt)
483 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
484 *
485 * Data frames are marked by T=0. All other fields are the same as
486 * those in L2TP control frames.
487 *
488 * L2TPv3 Data Message Header
489 *
490 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
491 * | L2TP Session Header |
492 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
493 * | L2-Specific Sublayer |
494 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
495 * | Tunnel Payload ...
496 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
497 *
498 * L2TPv3 Session Header Over IP
499 *
500 * 0 1 2 3
501 * 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
502 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
503 * | Session ID |
504 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
505 * | Cookie (optional, maximum 64 bits)...
506 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
507 * |
508 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
509 *
510 * L2TPv3 L2-Specific Sublayer Format
511 *
512 * 0 1 2 3
513 * 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
514 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
515 * |x|S|x|x|x|x|x|x| Sequence Number |
516 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
517 *
518 * Cookie value, sublayer format and offset (pad) are negotiated with
519 * the peer when the session is set up. Unlike L2TPv2, we do not need
520 * to parse the packet header to determine if optional fields are
521 * present.
522 *
523 * Caller must already have parsed the frame and determined that it is
524 * a data (not control) frame before coming here. Fields up to the
525 * session-id have already been parsed and ptr points to the data
526 * after the session-id.
James Chapmanfd558d12010-04-02 06:18:33 +0000527 */
James Chapmanf7faffa2010-04-02 06:18:49 +0000528void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
529 unsigned char *ptr, unsigned char *optr, u16 hdrflags,
530 int length, int (*payload_hook)(struct sk_buff *skb))
James Chapmanfd558d12010-04-02 06:18:33 +0000531{
James Chapmanf7faffa2010-04-02 06:18:49 +0000532 struct l2tp_tunnel *tunnel = session->tunnel;
James Chapmanfd558d12010-04-02 06:18:33 +0000533 int offset;
James Chapmanf7faffa2010-04-02 06:18:49 +0000534 u32 ns, nr;
James Chapmanfd558d12010-04-02 06:18:33 +0000535
536 /* The ref count is increased since we now hold a pointer to
537 * the session. Take care to decrement the refcnt when exiting
538 * this function from now on...
539 */
540 l2tp_session_inc_refcount(session);
541 if (session->ref)
542 (*session->ref)(session);
543
James Chapmanf7faffa2010-04-02 06:18:49 +0000544 /* Parse and check optional cookie */
545 if (session->peer_cookie_len > 0) {
546 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
547 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
548 "%s: cookie mismatch (%u/%u). Discarding.\n",
549 tunnel->name, tunnel->tunnel_id, session->session_id);
550 session->stats.rx_cookie_discards++;
551 goto discard;
552 }
553 ptr += session->peer_cookie_len;
554 }
555
James Chapmanfd558d12010-04-02 06:18:33 +0000556 /* Handle the optional sequence numbers. Sequence numbers are
557 * in different places for L2TPv2 and L2TPv3.
558 *
559 * If we are the LAC, enable/disable sequence numbers under
560 * the control of the LNS. If no sequence numbers present but
561 * we were expecting them, discard frame.
562 */
563 ns = nr = 0;
564 L2TP_SKB_CB(skb)->has_seq = 0;
James Chapmanf7faffa2010-04-02 06:18:49 +0000565 if (tunnel->version == L2TP_HDR_VER_2) {
566 if (hdrflags & L2TP_HDRFLAG_S) {
567 ns = ntohs(*(__be16 *) ptr);
568 ptr += 2;
569 nr = ntohs(*(__be16 *) ptr);
570 ptr += 2;
James Chapmanfd558d12010-04-02 06:18:33 +0000571
James Chapmanf7faffa2010-04-02 06:18:49 +0000572 /* Store L2TP info in the skb */
573 L2TP_SKB_CB(skb)->ns = ns;
574 L2TP_SKB_CB(skb)->has_seq = 1;
James Chapmanfd558d12010-04-02 06:18:33 +0000575
James Chapmanf7faffa2010-04-02 06:18:49 +0000576 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
577 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
578 session->name, ns, nr, session->nr);
579 }
580 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
581 u32 l2h = ntohl(*(__be32 *) ptr);
582
583 if (l2h & 0x40000000) {
584 ns = l2h & 0x00ffffff;
585
586 /* Store L2TP info in the skb */
587 L2TP_SKB_CB(skb)->ns = ns;
588 L2TP_SKB_CB(skb)->has_seq = 1;
589
590 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
591 "%s: recv data ns=%u, session nr=%u\n",
592 session->name, ns, session->nr);
593 }
James Chapmanfd558d12010-04-02 06:18:33 +0000594 }
595
James Chapmanf7faffa2010-04-02 06:18:49 +0000596 /* Advance past L2-specific header, if present */
597 ptr += session->l2specific_len;
598
James Chapmanfd558d12010-04-02 06:18:33 +0000599 if (L2TP_SKB_CB(skb)->has_seq) {
600 /* Received a packet with sequence numbers. If we're the LNS,
601 * check if we sre sending sequence numbers and if not,
602 * configure it so.
603 */
604 if ((!session->lns_mode) && (!session->send_seq)) {
605 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
606 "%s: requested to enable seq numbers by LNS\n",
607 session->name);
608 session->send_seq = -1;
James Chapmanf7faffa2010-04-02 06:18:49 +0000609 l2tp_session_set_header_len(session, tunnel->version);
James Chapmanfd558d12010-04-02 06:18:33 +0000610 }
611 } else {
612 /* No sequence numbers.
613 * If user has configured mandatory sequence numbers, discard.
614 */
615 if (session->recv_seq) {
616 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
617 "%s: recv data has no seq numbers when required. "
618 "Discarding\n", session->name);
619 session->stats.rx_seq_discards++;
620 goto discard;
621 }
622
623 /* If we're the LAC and we're sending sequence numbers, the
624 * LNS has requested that we no longer send sequence numbers.
625 * If we're the LNS and we're sending sequence numbers, the
626 * LAC is broken. Discard the frame.
627 */
628 if ((!session->lns_mode) && (session->send_seq)) {
629 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
630 "%s: requested to disable seq numbers by LNS\n",
631 session->name);
632 session->send_seq = 0;
James Chapmanf7faffa2010-04-02 06:18:49 +0000633 l2tp_session_set_header_len(session, tunnel->version);
James Chapmanfd558d12010-04-02 06:18:33 +0000634 } else if (session->send_seq) {
635 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
636 "%s: recv data has no seq numbers when required. "
637 "Discarding\n", session->name);
638 session->stats.rx_seq_discards++;
639 goto discard;
640 }
641 }
642
James Chapmanf7faffa2010-04-02 06:18:49 +0000643 /* Session data offset is handled differently for L2TPv2 and
644 * L2TPv3. For L2TPv2, there is an optional 16-bit value in
645 * the header. For L2TPv3, the offset is negotiated using AVPs
646 * in the session setup control protocol.
647 */
648 if (tunnel->version == L2TP_HDR_VER_2) {
649 /* If offset bit set, skip it. */
650 if (hdrflags & L2TP_HDRFLAG_O) {
651 offset = ntohs(*(__be16 *)ptr);
652 ptr += 2 + offset;
653 }
654 } else
655 ptr += session->offset;
James Chapmanfd558d12010-04-02 06:18:33 +0000656
657 offset = ptr - optr;
658 if (!pskb_may_pull(skb, offset))
659 goto discard;
660
661 __skb_pull(skb, offset);
662
663 /* If caller wants to process the payload before we queue the
664 * packet, do so now.
665 */
666 if (payload_hook)
667 if ((*payload_hook)(skb))
668 goto discard;
669
670 /* Prepare skb for adding to the session's reorder_q. Hold
671 * packets for max reorder_timeout or 1 second if not
672 * reordering.
673 */
674 L2TP_SKB_CB(skb)->length = length;
675 L2TP_SKB_CB(skb)->expires = jiffies +
676 (session->reorder_timeout ? session->reorder_timeout : HZ);
677
678 /* Add packet to the session's receive queue. Reordering is done here, if
679 * enabled. Saved L2TP protocol info is stored in skb->sb[].
680 */
681 if (L2TP_SKB_CB(skb)->has_seq) {
682 if (session->reorder_timeout != 0) {
683 /* Packet reordering enabled. Add skb to session's
684 * reorder queue, in order of ns.
685 */
686 l2tp_recv_queue_skb(session, skb);
687 } else {
688 /* Packet reordering disabled. Discard out-of-sequence
689 * packets
690 */
691 if (L2TP_SKB_CB(skb)->ns != session->nr) {
692 session->stats.rx_seq_discards++;
693 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
James Chapmanf7faffa2010-04-02 06:18:49 +0000694 "%s: oos pkt %u len %d discarded, "
695 "waiting for %u, reorder_q_len=%d\n",
James Chapmanfd558d12010-04-02 06:18:33 +0000696 session->name, L2TP_SKB_CB(skb)->ns,
697 L2TP_SKB_CB(skb)->length, session->nr,
698 skb_queue_len(&session->reorder_q));
699 goto discard;
700 }
701 skb_queue_tail(&session->reorder_q, skb);
702 }
703 } else {
704 /* No sequence numbers. Add the skb to the tail of the
705 * reorder queue. This ensures that it will be
706 * delivered after all previous sequenced skbs.
707 */
708 skb_queue_tail(&session->reorder_q, skb);
709 }
710
711 /* Try to dequeue as many skbs from reorder_q as we can. */
712 l2tp_recv_dequeue(session);
713
714 l2tp_session_dec_refcount(session);
715
James Chapmanf7faffa2010-04-02 06:18:49 +0000716 return;
James Chapmanfd558d12010-04-02 06:18:33 +0000717
718discard:
719 session->stats.rx_errors++;
720 kfree_skb(skb);
721
722 if (session->deref)
723 (*session->deref)(session);
724
725 l2tp_session_dec_refcount(session);
James Chapmanf7faffa2010-04-02 06:18:49 +0000726}
727EXPORT_SYMBOL(l2tp_recv_common);
728
729/* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
730 * here. The skb is not on a list when we get here.
731 * Returns 0 if the packet was a data packet and was successfully passed on.
732 * Returns 1 if the packet was not a good data packet and could not be
733 * forwarded. All such packets are passed up to userspace to deal with.
734 */
stephen hemmingerfc130842010-10-21 07:50:46 +0000735static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
736 int (*payload_hook)(struct sk_buff *skb))
James Chapmanf7faffa2010-04-02 06:18:49 +0000737{
738 struct l2tp_session *session = NULL;
739 unsigned char *ptr, *optr;
740 u16 hdrflags;
741 u32 tunnel_id, session_id;
742 int offset;
743 u16 version;
744 int length;
745
746 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
747 goto discard_bad_csum;
748
749 /* UDP always verifies the packet length. */
750 __skb_pull(skb, sizeof(struct udphdr));
751
752 /* Short packet? */
753 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
754 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
755 "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
756 goto error;
757 }
758
James Chapmanf7faffa2010-04-02 06:18:49 +0000759 /* Trace packet contents, if enabled */
760 if (tunnel->debug & L2TP_MSG_DATA) {
761 length = min(32u, skb->len);
762 if (!pskb_may_pull(skb, length))
763 goto error;
764
765 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
766
767 offset = 0;
768 do {
Eric Dumazete50e7052011-11-08 13:59:44 -0500769 printk(" %02X", skb->data[offset]);
James Chapmanf7faffa2010-04-02 06:18:49 +0000770 } while (++offset < length);
771
772 printk("\n");
773 }
774
Eric Dumazete50e7052011-11-08 13:59:44 -0500775 /* Point to L2TP header */
776 optr = ptr = skb->data;
777
James Chapmanf7faffa2010-04-02 06:18:49 +0000778 /* Get L2TP header flags */
779 hdrflags = ntohs(*(__be16 *) ptr);
780
781 /* Check protocol version */
782 version = hdrflags & L2TP_HDR_VER_MASK;
783 if (version != tunnel->version) {
784 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
785 "%s: recv protocol version mismatch: got %d expected %d\n",
786 tunnel->name, version, tunnel->version);
787 goto error;
788 }
789
790 /* Get length of L2TP packet */
791 length = skb->len;
792
793 /* If type is control packet, it is handled by userspace. */
794 if (hdrflags & L2TP_HDRFLAG_T) {
795 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
796 "%s: recv control packet, len=%d\n", tunnel->name, length);
797 goto error;
798 }
799
800 /* Skip flags */
801 ptr += 2;
802
803 if (tunnel->version == L2TP_HDR_VER_2) {
804 /* If length is present, skip it */
805 if (hdrflags & L2TP_HDRFLAG_L)
806 ptr += 2;
807
808 /* Extract tunnel and session ID */
809 tunnel_id = ntohs(*(__be16 *) ptr);
810 ptr += 2;
811 session_id = ntohs(*(__be16 *) ptr);
812 ptr += 2;
813 } else {
814 ptr += 2; /* skip reserved bits */
815 tunnel_id = tunnel->tunnel_id;
816 session_id = ntohl(*(__be32 *) ptr);
817 ptr += 4;
818 }
819
820 /* Find the session context */
821 session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id);
James Chapman309795f2010-04-02 06:19:10 +0000822 if (!session || !session->recv_skb) {
James Chapmanf7faffa2010-04-02 06:18:49 +0000823 /* Not found? Pass to userspace to deal with */
824 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
825 "%s: no session found (%u/%u). Passing up.\n",
826 tunnel->name, tunnel_id, session_id);
827 goto error;
828 }
829
830 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
James Chapmanfd558d12010-04-02 06:18:33 +0000831
832 return 0;
833
834discard_bad_csum:
835 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
836 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
837 tunnel->stats.rx_errors++;
838 kfree_skb(skb);
839
840 return 0;
841
842error:
843 /* Put UDP header back */
844 __skb_push(skb, sizeof(struct udphdr));
845
846 return 1;
847}
James Chapmanfd558d12010-04-02 06:18:33 +0000848
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,
David S. Millerd9d8da82011-05-06 22:23:20 -0700958 struct flowi *fl, 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;
David S. Millerd9d8da82011-05-06 22:23:20 -0700991 error = ip_queue_xmit(skb, fl);
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}
James Chapmanfd558d12010-04-02 06:18:33 +00001006
1007/* Automatically called when the skb is freed.
1008 */
1009static void l2tp_sock_wfree(struct sk_buff *skb)
1010{
1011 sock_put(skb->sk);
1012}
1013
1014/* For data skbs that we transmit, we associate with the tunnel socket
1015 * but don't do accounting.
1016 */
1017static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1018{
1019 sock_hold(sk);
1020 skb->sk = sk;
1021 skb->destructor = l2tp_sock_wfree;
1022}
1023
1024/* If caller requires the skb to have a ppp header, the header must be
1025 * inserted in the skb data before calling this function.
1026 */
1027int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
1028{
1029 int data_len = skb->len;
James Chapman0d767512010-04-02 06:19:00 +00001030 struct l2tp_tunnel *tunnel = session->tunnel;
1031 struct sock *sk = tunnel->sock;
David S. Millerd9d8da82011-05-06 22:23:20 -07001032 struct flowi *fl;
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);
Eric Dumazet835acf52011-10-07 05:35:46 +00001049 if (skb_cow_head(skb, headroom)) {
1050 dev_kfree_skb(skb);
James Chapmanfd558d12010-04-02 06:18:33 +00001051 goto abort;
Eric Dumazet835acf52011-10-07 05:35:46 +00001052 }
James Chapmanfd558d12010-04-02 06:18:33 +00001053
1054 new_headroom = skb_headroom(skb);
1055 skb_orphan(skb);
1056 skb->truesize += new_headroom - old_headroom;
1057
1058 /* Setup L2TP header */
James Chapmanf7faffa2010-04-02 06:18:49 +00001059 session->build_header(session, __skb_push(skb, hdr_len));
James Chapmanfd558d12010-04-02 06:18:33 +00001060
James Chapman0d767512010-04-02 06:19:00 +00001061 /* Reset skb netfilter state */
James Chapmanfd558d12010-04-02 06:18:33 +00001062 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1063 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1064 IPSKB_REROUTED);
1065 nf_reset(skb);
1066
David S. Miller6af88da2011-05-08 13:45:20 -07001067 bh_lock_sock(sk);
1068 if (sock_owned_by_user(sk)) {
1069 dev_kfree_skb(skb);
1070 goto out_unlock;
1071 }
1072
James Chapmanfd558d12010-04-02 06:18:33 +00001073 /* Get routing info from the tunnel socket */
1074 skb_dst_drop(skb);
Florian Westphal71b13912011-11-25 06:47:16 +00001075 skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
James Chapmanfd558d12010-04-02 06:18:33 +00001076
David S. Millerd9d8da82011-05-06 22:23:20 -07001077 inet = inet_sk(sk);
1078 fl = &inet->cork.fl;
James Chapman0d767512010-04-02 06:19:00 +00001079 switch (tunnel->encap) {
1080 case L2TP_ENCAPTYPE_UDP:
1081 /* Setup UDP header */
James Chapman0d767512010-04-02 06:19:00 +00001082 __skb_push(skb, sizeof(*uh));
1083 skb_reset_transport_header(skb);
1084 uh = udp_hdr(skb);
1085 uh->source = inet->inet_sport;
1086 uh->dest = inet->inet_dport;
1087 udp_len = uhlen + hdr_len + data_len;
1088 uh->len = htons(udp_len);
1089 uh->check = 0;
1090
1091 /* Calculate UDP checksum if configured to do so */
1092 if (sk->sk_no_check == UDP_CSUM_NOXMIT)
1093 skb->ip_summed = CHECKSUM_NONE;
1094 else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
1095 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
1096 skb->ip_summed = CHECKSUM_COMPLETE;
1097 csum = skb_checksum(skb, 0, udp_len, 0);
1098 uh->check = csum_tcpudp_magic(inet->inet_saddr,
1099 inet->inet_daddr,
1100 udp_len, IPPROTO_UDP, csum);
1101 if (uh->check == 0)
1102 uh->check = CSUM_MANGLED_0;
1103 } else {
1104 skb->ip_summed = CHECKSUM_PARTIAL;
1105 skb->csum_start = skb_transport_header(skb) - skb->head;
1106 skb->csum_offset = offsetof(struct udphdr, check);
1107 uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
1108 inet->inet_daddr,
1109 udp_len, IPPROTO_UDP, 0);
1110 }
1111 break;
1112
1113 case L2TP_ENCAPTYPE_IP:
1114 break;
James Chapmanfd558d12010-04-02 06:18:33 +00001115 }
1116
James Chapman0d767512010-04-02 06:19:00 +00001117 l2tp_skb_set_owner_w(skb, sk);
1118
David S. Millerd9d8da82011-05-06 22:23:20 -07001119 l2tp_xmit_core(session, skb, fl, data_len);
David S. Miller6af88da2011-05-08 13:45:20 -07001120out_unlock:
1121 bh_unlock_sock(sk);
James Chapmanfd558d12010-04-02 06:18:33 +00001122
1123abort:
1124 return 0;
1125}
1126EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
1127
1128/*****************************************************************************
1129 * Tinnel and session create/destroy.
1130 *****************************************************************************/
1131
1132/* Tunnel socket destruct hook.
1133 * The tunnel context is deleted only when all session sockets have been
1134 * closed.
1135 */
stephen hemmingerfc130842010-10-21 07:50:46 +00001136static void l2tp_tunnel_destruct(struct sock *sk)
James Chapmanfd558d12010-04-02 06:18:33 +00001137{
1138 struct l2tp_tunnel *tunnel;
1139
1140 tunnel = sk->sk_user_data;
1141 if (tunnel == NULL)
1142 goto end;
1143
1144 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1145 "%s: closing...\n", tunnel->name);
1146
1147 /* Close all sessions */
1148 l2tp_tunnel_closeall(tunnel);
1149
James Chapman0d767512010-04-02 06:19:00 +00001150 switch (tunnel->encap) {
1151 case L2TP_ENCAPTYPE_UDP:
1152 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1153 (udp_sk(sk))->encap_type = 0;
1154 (udp_sk(sk))->encap_rcv = NULL;
1155 break;
1156 case L2TP_ENCAPTYPE_IP:
1157 break;
1158 }
James Chapmanfd558d12010-04-02 06:18:33 +00001159
1160 /* Remove hooks into tunnel socket */
1161 tunnel->sock = NULL;
1162 sk->sk_destruct = tunnel->old_sk_destruct;
1163 sk->sk_user_data = NULL;
1164
1165 /* Call the original destructor */
1166 if (sk->sk_destruct)
1167 (*sk->sk_destruct)(sk);
1168
1169 /* We're finished with the socket */
1170 l2tp_tunnel_dec_refcount(tunnel);
1171
1172end:
1173 return;
1174}
James Chapmanfd558d12010-04-02 06:18:33 +00001175
1176/* When the tunnel is closed, all the attached sessions need to go too.
1177 */
stephen hemmingerfc130842010-10-21 07:50:46 +00001178static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
James Chapmanfd558d12010-04-02 06:18:33 +00001179{
1180 int hash;
1181 struct hlist_node *walk;
1182 struct hlist_node *tmp;
1183 struct l2tp_session *session;
1184
1185 BUG_ON(tunnel == NULL);
1186
1187 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1188 "%s: closing all sessions...\n", tunnel->name);
1189
1190 write_lock_bh(&tunnel->hlist_lock);
1191 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
1192again:
1193 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1194 session = hlist_entry(walk, struct l2tp_session, hlist);
1195
1196 PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO,
1197 "%s: closing session\n", session->name);
1198
1199 hlist_del_init(&session->hlist);
1200
1201 /* Since we should hold the sock lock while
1202 * doing any unbinding, we need to release the
1203 * lock we're holding before taking that lock.
1204 * Hold a reference to the sock so it doesn't
1205 * disappear as we're jumping between locks.
1206 */
1207 if (session->ref != NULL)
1208 (*session->ref)(session);
1209
1210 write_unlock_bh(&tunnel->hlist_lock);
1211
James Chapmanf7faffa2010-04-02 06:18:49 +00001212 if (tunnel->version != L2TP_HDR_VER_2) {
1213 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1214
James Chapmane02d4942010-04-02 06:19:16 +00001215 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1216 hlist_del_init_rcu(&session->global_hlist);
1217 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1218 synchronize_rcu();
James Chapmanf7faffa2010-04-02 06:18:49 +00001219 }
1220
James Chapmanfd558d12010-04-02 06:18:33 +00001221 if (session->session_close != NULL)
1222 (*session->session_close)(session);
1223
1224 if (session->deref != NULL)
1225 (*session->deref)(session);
1226
1227 write_lock_bh(&tunnel->hlist_lock);
1228
1229 /* Now restart from the beginning of this hash
1230 * chain. We always remove a session from the
1231 * list so we are guaranteed to make forward
1232 * progress.
1233 */
1234 goto again;
1235 }
1236 }
1237 write_unlock_bh(&tunnel->hlist_lock);
1238}
James Chapmanfd558d12010-04-02 06:18:33 +00001239
1240/* Really kill the tunnel.
1241 * Come here only when all sessions have been cleared from the tunnel.
1242 */
stephen hemmingerfc130842010-10-21 07:50:46 +00001243static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
James Chapmanfd558d12010-04-02 06:18:33 +00001244{
1245 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1246
1247 BUG_ON(atomic_read(&tunnel->ref_count) != 0);
1248 BUG_ON(tunnel->sock != NULL);
1249
1250 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
1251 "%s: free...\n", tunnel->name);
1252
1253 /* Remove from tunnel list */
James Chapmane02d4942010-04-02 06:19:16 +00001254 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1255 list_del_rcu(&tunnel->list);
1256 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
1257 synchronize_rcu();
James Chapmanfd558d12010-04-02 06:18:33 +00001258
1259 atomic_dec(&l2tp_tunnel_count);
1260 kfree(tunnel);
1261}
James Chapmanfd558d12010-04-02 06:18:33 +00001262
James Chapman789a4a22010-04-02 06:19:40 +00001263/* Create a socket for the tunnel, if one isn't set up by
1264 * userspace. This is used for static tunnels where there is no
1265 * managing L2TP daemon.
1266 */
1267static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
1268{
1269 int err = -EINVAL;
1270 struct sockaddr_in udp_addr;
1271 struct sockaddr_l2tpip ip_addr;
Eric Dumazet7bddd0d2010-04-04 01:02:46 -07001272 struct socket *sock = NULL;
James Chapman789a4a22010-04-02 06:19:40 +00001273
1274 switch (cfg->encap) {
1275 case L2TP_ENCAPTYPE_UDP:
1276 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
1277 if (err < 0)
1278 goto out;
1279
1280 sock = *sockp;
1281
1282 memset(&udp_addr, 0, sizeof(udp_addr));
1283 udp_addr.sin_family = AF_INET;
1284 udp_addr.sin_addr = cfg->local_ip;
1285 udp_addr.sin_port = htons(cfg->local_udp_port);
1286 err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr));
1287 if (err < 0)
1288 goto out;
1289
1290 udp_addr.sin_family = AF_INET;
1291 udp_addr.sin_addr = cfg->peer_ip;
1292 udp_addr.sin_port = htons(cfg->peer_udp_port);
1293 err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0);
1294 if (err < 0)
1295 goto out;
1296
1297 if (!cfg->use_udp_checksums)
1298 sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
1299
1300 break;
1301
1302 case L2TP_ENCAPTYPE_IP:
1303 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
1304 if (err < 0)
1305 goto out;
1306
1307 sock = *sockp;
1308
1309 memset(&ip_addr, 0, sizeof(ip_addr));
1310 ip_addr.l2tp_family = AF_INET;
1311 ip_addr.l2tp_addr = cfg->local_ip;
1312 ip_addr.l2tp_conn_id = tunnel_id;
1313 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr));
1314 if (err < 0)
1315 goto out;
1316
1317 ip_addr.l2tp_family = AF_INET;
1318 ip_addr.l2tp_addr = cfg->peer_ip;
1319 ip_addr.l2tp_conn_id = peer_tunnel_id;
1320 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0);
1321 if (err < 0)
1322 goto out;
1323
1324 break;
1325
1326 default:
1327 goto out;
1328 }
1329
1330out:
1331 if ((err < 0) && sock) {
1332 sock_release(sock);
1333 *sockp = NULL;
1334 }
1335
1336 return err;
1337}
1338
James Chapmanfd558d12010-04-02 06:18:33 +00001339int 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)
1340{
1341 struct l2tp_tunnel *tunnel = NULL;
1342 int err;
1343 struct socket *sock = NULL;
1344 struct sock *sk = NULL;
1345 struct l2tp_net *pn;
James Chapman0d767512010-04-02 06:19:00 +00001346 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
James Chapmanfd558d12010-04-02 06:18:33 +00001347
1348 /* Get the tunnel socket from the fd, which was opened by
James Chapman789a4a22010-04-02 06:19:40 +00001349 * the userspace L2TP daemon. If not specified, create a
1350 * kernel socket.
James Chapmanfd558d12010-04-02 06:18:33 +00001351 */
James Chapman789a4a22010-04-02 06:19:40 +00001352 if (fd < 0) {
1353 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
1354 if (err < 0)
1355 goto err;
1356 } else {
1357 err = -EBADF;
1358 sock = sockfd_lookup(fd, &err);
1359 if (!sock) {
1360 printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1361 tunnel_id, fd, err);
1362 goto err;
1363 }
James Chapmanfd558d12010-04-02 06:18:33 +00001364 }
1365
1366 sk = sock->sk;
1367
James Chapman0d767512010-04-02 06:19:00 +00001368 if (cfg != NULL)
1369 encap = cfg->encap;
1370
James Chapmanfd558d12010-04-02 06:18:33 +00001371 /* Quick sanity checks */
James Chapman0d767512010-04-02 06:19:00 +00001372 switch (encap) {
1373 case L2TP_ENCAPTYPE_UDP:
1374 err = -EPROTONOSUPPORT;
1375 if (sk->sk_protocol != IPPROTO_UDP) {
1376 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1377 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1378 goto err;
1379 }
1380 break;
1381 case L2TP_ENCAPTYPE_IP:
1382 err = -EPROTONOSUPPORT;
1383 if (sk->sk_protocol != IPPROTO_L2TP) {
1384 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1385 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
1386 goto err;
1387 }
1388 break;
James Chapmanfd558d12010-04-02 06:18:33 +00001389 }
1390
1391 /* Check if this socket has already been prepped */
1392 tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
1393 if (tunnel != NULL) {
1394 /* This socket has already been prepped */
1395 err = -EBUSY;
1396 goto err;
1397 }
1398
James Chapmanfd558d12010-04-02 06:18:33 +00001399 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
1400 if (tunnel == NULL) {
1401 err = -ENOMEM;
1402 goto err;
1403 }
1404
1405 tunnel->version = version;
1406 tunnel->tunnel_id = tunnel_id;
1407 tunnel->peer_tunnel_id = peer_tunnel_id;
1408 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
1409
1410 tunnel->magic = L2TP_TUNNEL_MAGIC;
1411 sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
1412 rwlock_init(&tunnel->hlist_lock);
1413
1414 /* The net we belong to */
1415 tunnel->l2tp_net = net;
1416 pn = l2tp_pernet(net);
1417
James Chapman0d767512010-04-02 06:19:00 +00001418 if (cfg != NULL)
James Chapmanfd558d12010-04-02 06:18:33 +00001419 tunnel->debug = cfg->debug;
1420
1421 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
James Chapman0d767512010-04-02 06:19:00 +00001422 tunnel->encap = encap;
1423 if (encap == L2TP_ENCAPTYPE_UDP) {
1424 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1425 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
1426 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
1427 }
James Chapmanfd558d12010-04-02 06:18:33 +00001428
1429 sk->sk_user_data = tunnel;
1430
1431 /* Hook on the tunnel socket destructor so that we can cleanup
1432 * if the tunnel socket goes away.
1433 */
1434 tunnel->old_sk_destruct = sk->sk_destruct;
1435 sk->sk_destruct = &l2tp_tunnel_destruct;
1436 tunnel->sock = sk;
1437 sk->sk_allocation = GFP_ATOMIC;
1438
1439 /* Add tunnel to our list */
1440 INIT_LIST_HEAD(&tunnel->list);
James Chapmanfd558d12010-04-02 06:18:33 +00001441 atomic_inc(&l2tp_tunnel_count);
1442
1443 /* Bump the reference count. The tunnel context is deleted
Eric Dumazet17691922011-05-11 18:22:36 +00001444 * only when this drops to zero. Must be done before list insertion
James Chapmanfd558d12010-04-02 06:18:33 +00001445 */
1446 l2tp_tunnel_inc_refcount(tunnel);
Eric Dumazet17691922011-05-11 18:22:36 +00001447 spin_lock_bh(&pn->l2tp_tunnel_list_lock);
1448 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
1449 spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
James Chapmanfd558d12010-04-02 06:18:33 +00001450
1451 err = 0;
1452err:
1453 if (tunnelp)
1454 *tunnelp = tunnel;
1455
James Chapman789a4a22010-04-02 06:19:40 +00001456 /* If tunnel's socket was created by the kernel, it doesn't
1457 * have a file.
1458 */
1459 if (sock && sock->file)
James Chapmanfd558d12010-04-02 06:18:33 +00001460 sockfd_put(sock);
1461
1462 return err;
1463}
1464EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
1465
James Chapman309795f2010-04-02 06:19:10 +00001466/* This function is used by the netlink TUNNEL_DELETE command.
1467 */
1468int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
1469{
1470 int err = 0;
James Chapman789a4a22010-04-02 06:19:40 +00001471 struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL;
James Chapman309795f2010-04-02 06:19:10 +00001472
1473 /* Force the tunnel socket to close. This will eventually
1474 * cause the tunnel to be deleted via the normal socket close
1475 * mechanisms when userspace closes the tunnel socket.
1476 */
James Chapman789a4a22010-04-02 06:19:40 +00001477 if (sock != NULL) {
1478 err = inet_shutdown(sock, 2);
1479
1480 /* If the tunnel's socket was created by the kernel,
1481 * close the socket here since the socket was not
1482 * created by userspace.
1483 */
1484 if (sock->file == NULL)
1485 err = inet_release(sock);
1486 }
James Chapman309795f2010-04-02 06:19:10 +00001487
1488 return err;
1489}
1490EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
1491
James Chapmanfd558d12010-04-02 06:18:33 +00001492/* Really kill the session.
1493 */
1494void l2tp_session_free(struct l2tp_session *session)
1495{
1496 struct l2tp_tunnel *tunnel;
1497
1498 BUG_ON(atomic_read(&session->ref_count) != 0);
1499
1500 tunnel = session->tunnel;
1501 if (tunnel != NULL) {
1502 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1503
1504 /* Delete the session from the hash */
1505 write_lock_bh(&tunnel->hlist_lock);
1506 hlist_del_init(&session->hlist);
1507 write_unlock_bh(&tunnel->hlist_lock);
1508
James Chapmanf7faffa2010-04-02 06:18:49 +00001509 /* Unlink from the global hash if not L2TPv2 */
1510 if (tunnel->version != L2TP_HDR_VER_2) {
1511 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1512
James Chapmane02d4942010-04-02 06:19:16 +00001513 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1514 hlist_del_init_rcu(&session->global_hlist);
1515 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
1516 synchronize_rcu();
James Chapmanf7faffa2010-04-02 06:18:49 +00001517 }
1518
James Chapmanfd558d12010-04-02 06:18:33 +00001519 if (session->session_id != 0)
1520 atomic_dec(&l2tp_session_count);
1521
1522 sock_put(tunnel->sock);
1523
1524 /* This will delete the tunnel context if this
1525 * is the last session on the tunnel.
1526 */
1527 session->tunnel = NULL;
1528 l2tp_tunnel_dec_refcount(tunnel);
1529 }
1530
1531 kfree(session);
1532
1533 return;
1534}
1535EXPORT_SYMBOL_GPL(l2tp_session_free);
1536
James Chapman309795f2010-04-02 06:19:10 +00001537/* This function is used by the netlink SESSION_DELETE command and by
1538 pseudowire modules.
1539 */
1540int l2tp_session_delete(struct l2tp_session *session)
1541{
1542 if (session->session_close != NULL)
1543 (*session->session_close)(session);
1544
1545 l2tp_session_dec_refcount(session);
1546
1547 return 0;
1548}
1549EXPORT_SYMBOL_GPL(l2tp_session_delete);
1550
1551
James Chapmanf7faffa2010-04-02 06:18:49 +00001552/* We come here whenever a session's send_seq, cookie_len or
1553 * l2specific_len parameters are set.
1554 */
stephen hemmingerfc130842010-10-21 07:50:46 +00001555static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
James Chapmanf7faffa2010-04-02 06:18:49 +00001556{
1557 if (version == L2TP_HDR_VER_2) {
1558 session->hdr_len = 6;
1559 if (session->send_seq)
1560 session->hdr_len += 4;
1561 } else {
James Chapman0d767512010-04-02 06:19:00 +00001562 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
1563 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
1564 session->hdr_len += 4;
James Chapmanf7faffa2010-04-02 06:18:49 +00001565 }
1566
1567}
James Chapmanf7faffa2010-04-02 06:18:49 +00001568
James Chapmanfd558d12010-04-02 06:18:33 +00001569struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
1570{
1571 struct l2tp_session *session;
1572
1573 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL);
1574 if (session != NULL) {
1575 session->magic = L2TP_SESSION_MAGIC;
1576 session->tunnel = tunnel;
1577
1578 session->session_id = session_id;
1579 session->peer_session_id = peer_session_id;
James Chapmanf7faffa2010-04-02 06:18:49 +00001580 session->nr = 1;
James Chapmanfd558d12010-04-02 06:18:33 +00001581
1582 sprintf(&session->name[0], "sess %u/%u",
1583 tunnel->tunnel_id, session->session_id);
1584
1585 skb_queue_head_init(&session->reorder_q);
1586
1587 INIT_HLIST_NODE(&session->hlist);
James Chapmanf7faffa2010-04-02 06:18:49 +00001588 INIT_HLIST_NODE(&session->global_hlist);
James Chapmanfd558d12010-04-02 06:18:33 +00001589
1590 /* Inherit debug options from tunnel */
1591 session->debug = tunnel->debug;
1592
1593 if (cfg) {
James Chapmanf7faffa2010-04-02 06:18:49 +00001594 session->pwtype = cfg->pw_type;
James Chapmanfd558d12010-04-02 06:18:33 +00001595 session->debug = cfg->debug;
James Chapmanfd558d12010-04-02 06:18:33 +00001596 session->mtu = cfg->mtu;
1597 session->mru = cfg->mru;
1598 session->send_seq = cfg->send_seq;
1599 session->recv_seq = cfg->recv_seq;
1600 session->lns_mode = cfg->lns_mode;
James Chapmanf7faffa2010-04-02 06:18:49 +00001601 session->reorder_timeout = cfg->reorder_timeout;
1602 session->offset = cfg->offset;
1603 session->l2specific_type = cfg->l2specific_type;
1604 session->l2specific_len = cfg->l2specific_len;
1605 session->cookie_len = cfg->cookie_len;
1606 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
1607 session->peer_cookie_len = cfg->peer_cookie_len;
1608 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
James Chapmanfd558d12010-04-02 06:18:33 +00001609 }
1610
James Chapmanf7faffa2010-04-02 06:18:49 +00001611 if (tunnel->version == L2TP_HDR_VER_2)
1612 session->build_header = l2tp_build_l2tpv2_header;
1613 else
1614 session->build_header = l2tp_build_l2tpv3_header;
1615
1616 l2tp_session_set_header_len(session, tunnel->version);
1617
James Chapmanfd558d12010-04-02 06:18:33 +00001618 /* Bump the reference count. The session context is deleted
1619 * only when this drops to zero.
1620 */
1621 l2tp_session_inc_refcount(session);
1622 l2tp_tunnel_inc_refcount(tunnel);
1623
1624 /* Ensure tunnel socket isn't deleted */
1625 sock_hold(tunnel->sock);
1626
1627 /* Add session to the tunnel's hash list */
1628 write_lock_bh(&tunnel->hlist_lock);
1629 hlist_add_head(&session->hlist,
1630 l2tp_session_id_hash(tunnel, session_id));
1631 write_unlock_bh(&tunnel->hlist_lock);
1632
James Chapmanf7faffa2010-04-02 06:18:49 +00001633 /* And to the global session list if L2TPv3 */
1634 if (tunnel->version != L2TP_HDR_VER_2) {
1635 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
1636
James Chapmane02d4942010-04-02 06:19:16 +00001637 spin_lock_bh(&pn->l2tp_session_hlist_lock);
1638 hlist_add_head_rcu(&session->global_hlist,
1639 l2tp_session_id_hash_2(pn, session_id));
1640 spin_unlock_bh(&pn->l2tp_session_hlist_lock);
James Chapmanf7faffa2010-04-02 06:18:49 +00001641 }
1642
James Chapmanfd558d12010-04-02 06:18:33 +00001643 /* Ignore management session in session count value */
1644 if (session->session_id != 0)
1645 atomic_inc(&l2tp_session_count);
1646 }
1647
1648 return session;
1649}
1650EXPORT_SYMBOL_GPL(l2tp_session_create);
1651
1652/*****************************************************************************
1653 * Init and cleanup
1654 *****************************************************************************/
1655
1656static __net_init int l2tp_init_net(struct net *net)
1657{
Jiri Pirkoe773aaf2010-04-23 00:53:39 +00001658 struct l2tp_net *pn = net_generic(net, l2tp_net_id);
James Chapmanf7faffa2010-04-02 06:18:49 +00001659 int hash;
James Chapmanfd558d12010-04-02 06:18:33 +00001660
James Chapmanfd558d12010-04-02 06:18:33 +00001661 INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
James Chapmane02d4942010-04-02 06:19:16 +00001662 spin_lock_init(&pn->l2tp_tunnel_list_lock);
James Chapmanfd558d12010-04-02 06:18:33 +00001663
James Chapmanf7faffa2010-04-02 06:18:49 +00001664 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
1665 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
1666
James Chapmane02d4942010-04-02 06:19:16 +00001667 spin_lock_init(&pn->l2tp_session_hlist_lock);
James Chapmanf7faffa2010-04-02 06:18:49 +00001668
James Chapmanfd558d12010-04-02 06:18:33 +00001669 return 0;
James Chapmanfd558d12010-04-02 06:18:33 +00001670}
1671
1672static struct pernet_operations l2tp_net_ops = {
1673 .init = l2tp_init_net,
James Chapmanfd558d12010-04-02 06:18:33 +00001674 .id = &l2tp_net_id,
1675 .size = sizeof(struct l2tp_net),
1676};
1677
1678static int __init l2tp_init(void)
1679{
1680 int rc = 0;
1681
1682 rc = register_pernet_device(&l2tp_net_ops);
1683 if (rc)
1684 goto out;
1685
1686 printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION);
1687
1688out:
1689 return rc;
1690}
1691
1692static void __exit l2tp_exit(void)
1693{
1694 unregister_pernet_device(&l2tp_net_ops);
1695}
1696
1697module_init(l2tp_init);
1698module_exit(l2tp_exit);
1699
1700MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1701MODULE_DESCRIPTION("L2TP core");
1702MODULE_LICENSE("GPL");
1703MODULE_VERSION(L2TP_DRV_VERSION);
1704