1 /*****************************************************************************
2 * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
3 *
4 * PPPoX --- Generic PPP encapsulation socket family
5 * PPPoL2TP --- PPP over L2TP (RFC 2661)
6 *
7 * Version: 1.0.0
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 * License:
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License
19 * as published by the Free Software Foundation; either version
20 * 2 of the License, or (at your option) any later version.
21 *
22 */
23
24 /* This driver handles only L2TP data frames; control frames are handled by a
25 * userspace application.
26 *
27 * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
28 * attaches it to a bound UDP socket with local tunnel_id / session_id and
29 * peer tunnel_id / session_id set. Data can then be sent or received using
30 * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
31 * can be read or modified using ioctl() or [gs]etsockopt() calls.
32 *
33 * When a PPPoL2TP socket is connected with local and peer session_id values
34 * zero, the socket is treated as a special tunnel management socket.
35 *
36 * Here's example userspace code to create a socket for sending/receiving data
37 * over an L2TP session:-
38 *
39 * struct sockaddr_pppol2tp sax;
40 * int fd;
41 * int session_fd;
42 *
43 * fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
44 *
45 * sax.sa_family = AF_PPPOX;
46 * sax.sa_protocol = PX_PROTO_OL2TP;
47 * sax.pppol2tp.fd = tunnel_fd; // bound UDP socket
48 * sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
49 * sax.pppol2tp.addr.sin_port = addr->sin_port;
50 * sax.pppol2tp.addr.sin_family = AF_INET;
51 * sax.pppol2tp.s_tunnel = tunnel_id;
52 * sax.pppol2tp.s_session = session_id;
53 * sax.pppol2tp.d_tunnel = peer_tunnel_id;
54 * sax.pppol2tp.d_session = peer_session_id;
55 *
56 * session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
57 *
58 * A pppd plugin that allows PPP traffic to be carried over L2TP using
59 * this driver is available from the OpenL2TP project at
60 * http://openl2tp.sourceforge.net.
61 */
62
63 #include <linux/module.h>
64 #include <linux/version.h>
65 #include <linux/string.h>
66 #include <linux/list.h>
67 #include <asm/uaccess.h>
68
69 #include <linux/kernel.h>
70 #include <linux/spinlock.h>
71 #include <linux/kthread.h>
72 #include <linux/sched.h>
73 #include <linux/slab.h>
74 #include <linux/errno.h>
75 #include <linux/jiffies.h>
76
77 #include <linux/netdevice.h>
78 #include <linux/net.h>
79 #include <linux/inetdevice.h>
80 #include <linux/skbuff.h>
81 #include <linux/init.h>
82 #include <linux/ip.h>
83 #include <linux/udp.h>
84 #include <linux/if_pppox.h>
85 #include <linux/if_pppol2tp.h>
86 #include <net/sock.h>
87 #include <linux/ppp_channel.h>
88 #include <linux/ppp_defs.h>
89 #include <linux/if_ppp.h>
90 #include <linux/file.h>
91 #include <linux/hash.h>
92 #include <linux/sort.h>
93 #include <linux/proc_fs.h>
94 #include <net/net_namespace.h>
95 #include <net/dst.h>
96 #include <net/ip.h>
97 #include <net/udp.h>
98 #include <net/xfrm.h>
99
100 #include <asm/byteorder.h>
101 #include <asm/atomic.h>
102
103
104 #define PPPOL2TP_DRV_VERSION "V1.0"
105
106 /* L2TP header constants */
107 #define L2TP_HDRFLAG_T 0x8000
108 #define L2TP_HDRFLAG_L 0x4000
109 #define L2TP_HDRFLAG_S 0x0800
110 #define L2TP_HDRFLAG_O 0x0200
111 #define L2TP_HDRFLAG_P 0x0100
112
113 #define L2TP_HDR_VER_MASK 0x000F
114 #define L2TP_HDR_VER 0x0002
115
116 /* Space for UDP, L2TP and PPP headers */
117 #define PPPOL2TP_HEADER_OVERHEAD 40
118
119 /* Just some random numbers */
120 #define L2TP_TUNNEL_MAGIC 0x42114DDA
121 #define L2TP_SESSION_MAGIC 0x0C04EB7D
122
123 #define PPPOL2TP_HASH_BITS 4
124 #define PPPOL2TP_HASH_SIZE (1 << PPPOL2TP_HASH_BITS)
125
126 /* Default trace flags */
127 #define PPPOL2TP_DEFAULT_DEBUG_FLAGS 0
128
129 #define PRINTK(_mask, _type, _lvl, _fmt, args...) \
130 do { \
131 if ((_mask) & (_type)) \
132 printk(_lvl "PPPOL2TP: " _fmt, ##args); \
133 } while(0)
134
135 /* Number of bytes to build transmit L2TP headers.
136 * Unfortunately the size is different depending on whether sequence numbers
137 * are enabled.
138 */
139 #define PPPOL2TP_L2TP_HDR_SIZE_SEQ 10
140 #define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ 6
141
142 struct pppol2tp_tunnel;
143
144 /* Describes a session. It is the sk_user_data field in the PPPoL2TP
145 * socket. Contains information to determine incoming packets and transmit
146 * outgoing ones.
147 */
148 struct pppol2tp_session
149 {
150 int magic; /* should be
151 * L2TP_SESSION_MAGIC */
152 int owner; /* pid that opened the socket */
153
154 struct sock *sock; /* Pointer to the session
155 * PPPoX socket */
156 struct sock *tunnel_sock; /* Pointer to the tunnel UDP
157 * socket */
158
159 struct pppol2tp_addr tunnel_addr; /* Description of tunnel */
160
161 struct pppol2tp_tunnel *tunnel; /* back pointer to tunnel
162 * context */
163
164 char name[20]; /* "sess xxxxx/yyyyy", where
165 * x=tunnel_id, y=session_id */
166 int mtu;
167 int mru;
168 int flags; /* accessed by PPPIOCGFLAGS.
169 * Unused. */
170 unsigned recv_seq:1; /* expect receive packets with
171 * sequence numbers? */
172 unsigned send_seq:1; /* send packets with sequence
173 * numbers? */
174 unsigned lns_mode:1; /* behave as LNS? LAC enables
175 * sequence numbers under
176 * control of LNS. */
177 int debug; /* bitmask of debug message
178 * categories */
179 int reorder_timeout; /* configured reorder timeout
180 * (in jiffies) */
181 u16 nr; /* session NR state (receive) */
182 u16 ns; /* session NR state (send) */
183 struct sk_buff_head reorder_q; /* receive reorder queue */
184 struct pppol2tp_ioc_stats stats;
185 struct hlist_node hlist; /* Hash list node */
186 };
187
188 /* The sk_user_data field of the tunnel's UDP socket. It contains info to track
189 * all the associated sessions so incoming packets can be sorted out
190 */
191 struct pppol2tp_tunnel
192 {
193 int magic; /* Should be L2TP_TUNNEL_MAGIC */
194 rwlock_t hlist_lock; /* protect session_hlist */
195 struct hlist_head session_hlist[PPPOL2TP_HASH_SIZE];
196 /* hashed list of sessions,
197 * hashed by id */
198 int debug; /* bitmask of debug message
199 * categories */
200 char name[12]; /* "tunl xxxxx" */
201 struct pppol2tp_ioc_stats stats;
202
203 void (*old_sk_destruct)(struct sock *);
204
205 struct sock *sock; /* Parent socket */
206 struct list_head list; /* Keep a list of all open
207 * prepared sockets */
208
209 atomic_t ref_count;
210 };
211
212 /* Private data stored for received packets in the skb.
213 */
214 struct pppol2tp_skb_cb {
215 u16 ns;
216 u16 nr;
217 u16 has_seq;
218 u16 length;
219 unsigned long expires;
220 };
221
222 #define PPPOL2TP_SKB_CB(skb) ((struct pppol2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
223
224 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
225 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel);
226
227 static atomic_t pppol2tp_tunnel_count;
228 static atomic_t pppol2tp_session_count;
229 static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL };
230 static struct proto_ops pppol2tp_ops;
231 static LIST_HEAD(pppol2tp_tunnel_list);
232 static DEFINE_RWLOCK(pppol2tp_tunnel_list_lock);
233
234 /* Helpers to obtain tunnel/session contexts from sockets.
235 */
236 static inline struct pppol2tp_session *pppol2tp_sock_to_session(struct sock *sk)
237 {
238 struct pppol2tp_session *session;
239
240 if (sk == NULL)
241 return NULL;
242
243 sock_hold(sk);
244 session = (struct pppol2tp_session *)(sk->sk_user_data);
245 if (session == NULL) {
246 sock_put(sk);
247 goto out;
248 }
249
250 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
251 out:
252 return session;
253 }
254
255 static inline struct pppol2tp_tunnel *pppol2tp_sock_to_tunnel(struct sock *sk)
256 {
257 struct pppol2tp_tunnel *tunnel;
258
259 if (sk == NULL)
260 return NULL;
261
262 sock_hold(sk);
263 tunnel = (struct pppol2tp_tunnel *)(sk->sk_user_data);
264 if (tunnel == NULL) {
265 sock_put(sk);
266 goto out;
267 }
268
269 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
270 out:
271 return tunnel;
272 }
273
274 /* Tunnel reference counts. Incremented per session that is added to
275 * the tunnel.
276 */
277 static inline void pppol2tp_tunnel_inc_refcount(struct pppol2tp_tunnel *tunnel)
278 {
279 atomic_inc(&tunnel->ref_count);
280 }
281
282 static inline void pppol2tp_tunnel_dec_refcount(struct pppol2tp_tunnel *tunnel)
283 {
284 if (atomic_dec_and_test(&tunnel->ref_count))
285 pppol2tp_tunnel_free(tunnel);
286 }
287
288 /* Session hash list.
289 * The session_id SHOULD be random according to RFC2661, but several
290 * L2TP implementations (Cisco and Microsoft) use incrementing
291 * session_ids. So we do a real hash on the session_id, rather than a
292 * simple bitmask.
293 */
294 static inline struct hlist_head *
295 pppol2tp_session_id_hash(struct pppol2tp_tunnel *tunnel, u16 session_id)
296 {
297 unsigned long hash_val = (unsigned long) session_id;
298 return &tunnel->session_hlist[hash_long(hash_val, PPPOL2TP_HASH_BITS)];
299 }
300
301 /* Lookup a session by id
302 */
303 static struct pppol2tp_session *
304 pppol2tp_session_find(struct pppol2tp_tunnel *tunnel, u16 session_id)
305 {
306 struct hlist_head *session_list =
307 pppol2tp_session_id_hash(tunnel, session_id);
308 struct pppol2tp_session *session;
309 struct hlist_node *walk;
310
311 read_lock_bh(&tunnel->hlist_lock);
312 hlist_for_each_entry(session, walk, session_list, hlist) {
313 if (session->tunnel_addr.s_session == session_id) {
314 read_unlock_bh(&tunnel->hlist_lock);
315 return session;
316 }
317 }
318 read_unlock_bh(&tunnel->hlist_lock);
319
320 return NULL;
321 }
322
323 /* Lookup a tunnel by id
324 */
325 static struct pppol2tp_tunnel *pppol2tp_tunnel_find(u16 tunnel_id)
326 {
327 struct pppol2tp_tunnel *tunnel = NULL;
328
329 read_lock_bh(&pppol2tp_tunnel_list_lock);
330 list_for_each_entry(tunnel, &pppol2tp_tunnel_list, list) {
331 if (tunnel->stats.tunnel_id == tunnel_id) {
332 read_unlock_bh(&pppol2tp_tunnel_list_lock);
333 return tunnel;
334 }
335 }
336 read_unlock_bh(&pppol2tp_tunnel_list_lock);
337
338 return NULL;
339 }
340
341 /*****************************************************************************
342 * Receive data handling
343 *****************************************************************************/
344
345 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
346 * number.
347 */
348 static void pppol2tp_recv_queue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
349 {
350 struct sk_buff *skbp;
351 struct sk_buff *tmp;
352 u16 ns = PPPOL2TP_SKB_CB(skb)->ns;
353
354 spin_lock_bh(&session->reorder_q.lock);
355 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
356 if (PPPOL2TP_SKB_CB(skbp)->ns > ns) {
357 __skb_insert(skb, skbp->prev, skbp, &session->reorder_q);
358 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
359 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
360 session->name, ns, PPPOL2TP_SKB_CB(skbp)->ns,
361 skb_queue_len(&session->reorder_q));
362 session->stats.rx_oos_packets++;
363 goto out;
364 }
365 }
366
367 __skb_queue_tail(&session->reorder_q, skb);
368
369 out:
370 spin_unlock_bh(&session->reorder_q.lock);
371 }
372
373 /* Dequeue a single skb.
374 */
375 static void pppol2tp_recv_dequeue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
376 {
377 struct pppol2tp_tunnel *tunnel = session->tunnel;
378 int length = PPPOL2TP_SKB_CB(skb)->length;
379 struct sock *session_sock = NULL;
380
381 /* We're about to requeue the skb, so return resources
382 * to its current owner (a socket receive buffer).
383 */
384 skb_orphan(skb);
385
386 tunnel->stats.rx_packets++;
387 tunnel->stats.rx_bytes += length;
388 session->stats.rx_packets++;
389 session->stats.rx_bytes += length;
390
391 if (PPPOL2TP_SKB_CB(skb)->has_seq) {
392 /* Bump our Nr */
393 session->nr++;
394 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
395 "%s: updated nr to %hu\n", session->name, session->nr);
396 }
397
398 /* If the socket is bound, send it in to PPP's input queue. Otherwise
399 * queue it on the session socket.
400 */
401 session_sock = session->sock;
402 if (session_sock->sk_state & PPPOX_BOUND) {
403 struct pppox_sock *po;
404 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
405 "%s: recv %d byte data frame, passing to ppp\n",
406 session->name, length);
407
408 /* We need to forget all info related to the L2TP packet
409 * gathered in the skb as we are going to reuse the same
410 * skb for the inner packet.
411 * Namely we need to:
412 * - reset xfrm (IPSec) information as it applies to
413 * the outer L2TP packet and not to the inner one
414 * - release the dst to force a route lookup on the inner
415 * IP packet since skb->dst currently points to the dst
416 * of the UDP tunnel
417 * - reset netfilter information as it doesn't apply
418 * to the inner packet either
419 */
420 secpath_reset(skb);
421 dst_release(skb->dst);
422 skb->dst = NULL;
423 nf_reset(skb);
424
425 po = pppox_sk(session_sock);
426 ppp_input(&po->chan, skb);
427 } else {
428 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
429 "%s: socket not bound\n", session->name);
430
431 /* Not bound. Nothing we can do, so discard. */
432 session->stats.rx_errors++;
433 kfree_skb(skb);
434 }
435
436 sock_put(session->sock);
437 }
438
439 /* Dequeue skbs from the session's reorder_q, subject to packet order.
440 * Skbs that have been in the queue for too long are simply discarded.
441 */
442 static void pppol2tp_recv_dequeue(struct pppol2tp_session *session)
443 {
444 struct sk_buff *skb;
445 struct sk_buff *tmp;
446
447 /* If the pkt at the head of the queue has the nr that we
448 * expect to send up next, dequeue it and any other
449 * in-sequence packets behind it.
450 */
451 spin_lock_bh(&session->reorder_q.lock);
452 skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
453 if (time_after(jiffies, PPPOL2TP_SKB_CB(skb)->expires)) {
454 session->stats.rx_seq_discards++;
455 session->stats.rx_errors++;
456 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
457 "%s: oos pkt %hu len %d discarded (too old), "
458 "waiting for %hu, reorder_q_len=%d\n",
459 session->name, PPPOL2TP_SKB_CB(skb)->ns,
460 PPPOL2TP_SKB_CB(skb)->length, session->nr,
461 skb_queue_len(&session->reorder_q));
462 __skb_unlink(skb, &session->reorder_q);
463 kfree_skb(skb);
464 sock_put(session->sock);
465 continue;
466 }
467
468 if (PPPOL2TP_SKB_CB(skb)->has_seq) {
469 if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
470 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
471 "%s: holding oos pkt %hu len %d, "
472 "waiting for %hu, reorder_q_len=%d\n",
473 session->name, PPPOL2TP_SKB_CB(skb)->ns,
474 PPPOL2TP_SKB_CB(skb)->length, session->nr,
475 skb_queue_len(&session->reorder_q));
476 goto out;
477 }
478 }
479 __skb_unlink(skb, &session->reorder_q);
480
481 /* Process the skb. We release the queue lock while we
482 * do so to let other contexts process the queue.
483 */
484 spin_unlock_bh(&session->reorder_q.lock);
485 pppol2tp_recv_dequeue_skb(session, skb);
486 spin_lock_bh(&session->reorder_q.lock);
487 }
488
489 out:
490 spin_unlock_bh(&session->reorder_q.lock);
491 }
492
493 /* Internal receive frame. Do the real work of receiving an L2TP data frame
494 * here. The skb is not on a list when we get here.
495 * Returns 0 if the packet was a data packet and was successfully passed on.
496 * Returns 1 if the packet was not a good data packet and could not be
497 * forwarded. All such packets are passed up to userspace to deal with.
498 */
499 static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
500 {
501 struct pppol2tp_session *session = NULL;
502 struct pppol2tp_tunnel *tunnel;
503 unsigned char *ptr, *optr;
504 u16 hdrflags;
505 u16 tunnel_id, session_id;
506 int length;
507 int offset;
508
509 tunnel = pppol2tp_sock_to_tunnel(sock);
510 if (tunnel == NULL)
511 goto no_tunnel;
512
513 /* UDP always verifies the packet length. */
514 __skb_pull(skb, sizeof(struct udphdr));
515
516 /* Short packet? */
517 if (!pskb_may_pull(skb, 12)) {
518 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
519 "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
520 goto error;
521 }
522
523 /* Point to L2TP header */
524 optr = ptr = skb->data;
525
526 /* Get L2TP header flags */
527 hdrflags = ntohs(*(__be16*)ptr);
528
529 /* Trace packet contents, if enabled */
530 if (tunnel->debug & PPPOL2TP_MSG_DATA) {
531 length = min(16u, skb->len);
532 if (!pskb_may_pull(skb, length))
533 goto error;
534
535 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
536
537 offset = 0;
538 do {
539 printk(" %02X", ptr[offset]);
540 } while (++offset < length);
541
542 printk("\n");
543 }
544
545 /* Get length of L2TP packet */
546 length = skb->len;
547
548 /* If type is control packet, it is handled by userspace. */
549 if (hdrflags & L2TP_HDRFLAG_T) {
550 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
551 "%s: recv control packet, len=%d\n", tunnel->name, length);
552 goto error;
553 }
554
555 /* Skip flags */
556 ptr += 2;
557
558 /* If length is present, skip it */
559 if (hdrflags & L2TP_HDRFLAG_L)
560 ptr += 2;
561
562 /* Extract tunnel and session ID */
563 tunnel_id = ntohs(*(__be16 *) ptr);
564 ptr += 2;
565 session_id = ntohs(*(__be16 *) ptr);
566 ptr += 2;
567
568 /* Find the session context */
569 session = pppol2tp_session_find(tunnel, session_id);
570 if (!session) {
571 /* Not found? Pass to userspace to deal with */
572 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
573 "%s: no socket found (%hu/%hu). Passing up.\n",
574 tunnel->name, tunnel_id, session_id);
575 goto error;
576 }
577 sock_hold(session->sock);
578
579 /* The ref count on the socket was increased by the above call since
580 * we now hold a pointer to the session. Take care to do sock_put()
581 * when exiting this function from now on...
582 */
583
584 /* Handle the optional sequence numbers. If we are the LAC,
585 * enable/disable sequence numbers under the control of the LNS. If
586 * no sequence numbers present but we were expecting them, discard
587 * frame.
588 */
589 if (hdrflags & L2TP_HDRFLAG_S) {
590 u16 ns, nr;
591 ns = ntohs(*(__be16 *) ptr);
592 ptr += 2;
593 nr = ntohs(*(__be16 *) ptr);
594 ptr += 2;
595
596 /* Received a packet with sequence numbers. If we're the LNS,
597 * check if we sre sending sequence numbers and if not,
598 * configure it so.
599 */
600 if ((!session->lns_mode) && (!session->send_seq)) {
601 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
602 "%s: requested to enable seq numbers by LNS\n",
603 session->name);
604 session->send_seq = -1;
605 }
606
607 /* Store L2TP info in the skb */
608 PPPOL2TP_SKB_CB(skb)->ns = ns;
609 PPPOL2TP_SKB_CB(skb)->nr = nr;
610 PPPOL2TP_SKB_CB(skb)->has_seq = 1;
611
612 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
613 "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n",
614 session->name, ns, nr, session->nr);
615 } else {
616 /* No sequence numbers.
617 * If user has configured mandatory sequence numbers, discard.
618 */
619 if (session->recv_seq) {
620 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
621 "%s: recv data has no seq numbers when required. "
622 "Discarding\n", session->name);
623 session->stats.rx_seq_discards++;
624 goto discard;
625 }
626
627 /* If we're the LAC and we're sending sequence numbers, the
628 * LNS has requested that we no longer send sequence numbers.
629 * If we're the LNS and we're sending sequence numbers, the
630 * LAC is broken. Discard the frame.
631 */
632 if ((!session->lns_mode) && (session->send_seq)) {
633 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
634 "%s: requested to disable seq numbers by LNS\n",
635 session->name);
636 session->send_seq = 0;
637 } else if (session->send_seq) {
638 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
639 "%s: recv data has no seq numbers when required. "
640 "Discarding\n", session->name);
641 session->stats.rx_seq_discards++;
642 goto discard;
643 }
644
645 /* Store L2TP info in the skb */
646 PPPOL2TP_SKB_CB(skb)->has_seq = 0;
647 }
648
649 /* If offset bit set, skip it. */
650 if (hdrflags & L2TP_HDRFLAG_O) {
651 offset = ntohs(*(__be16 *)ptr);
652 ptr += 2 + offset;
653 }
654
655 offset = ptr - optr;
656 if (!pskb_may_pull(skb, offset))
657 goto discard;
658
659 __skb_pull(skb, offset);
660
661 /* Skip PPP header, if present. In testing, Microsoft L2TP clients
662 * don't send the PPP header (PPP header compression enabled), but
663 * other clients can include the header. So we cope with both cases
664 * here. The PPP header is always FF03 when using L2TP.
665 *
666 * Note that skb->data[] isn't dereferenced from a u16 ptr here since
667 * the field may be unaligned.
668 */
669 if (!pskb_may_pull(skb, 2))
670 goto discard;
671
672 if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
673 skb_pull(skb, 2);
674
675 /* Prepare skb for adding to the session's reorder_q. Hold
676 * packets for max reorder_timeout or 1 second if not
677 * reordering.
678 */
679 PPPOL2TP_SKB_CB(skb)->length = length;
680 PPPOL2TP_SKB_CB(skb)->expires = jiffies +
681 (session->reorder_timeout ? session->reorder_timeout : HZ);
682
683 /* Add packet to the session's receive queue. Reordering is done here, if
684 * enabled. Saved L2TP protocol info is stored in skb->sb[].
685 */
686 if (PPPOL2TP_SKB_CB(skb)->has_seq) {
687 if (session->reorder_timeout != 0) {
688 /* Packet reordering enabled. Add skb to session's
689 * reorder queue, in order of ns.
690 */
691 pppol2tp_recv_queue_skb(session, skb);
692 } else {
693 /* Packet reordering disabled. Discard out-of-sequence
694 * packets
695 */
696 if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
697 session->stats.rx_seq_discards++;
698 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
699 "%s: oos pkt %hu len %d discarded, "
700 "waiting for %hu, reorder_q_len=%d\n",
701 session->name, PPPOL2TP_SKB_CB(skb)->ns,
702 PPPOL2TP_SKB_CB(skb)->length, session->nr,
703 skb_queue_len(&session->reorder_q));
704 goto discard;
705 }
706 skb_queue_tail(&session->reorder_q, skb);
707 }
708 } else {
709 /* No sequence numbers. Add the skb to the tail of the
710 * reorder queue. This ensures that it will be
711 * delivered after all previous sequenced skbs.
712 */
713 skb_queue_tail(&session->reorder_q, skb);
714 }
715
716 /* Try to dequeue as many skbs from reorder_q as we can. */
717 pppol2tp_recv_dequeue(session);
718
719 return 0;
720
721 discard:
722 session->stats.rx_errors++;
723 kfree_skb(skb);
724 sock_put(session->sock);
725 sock_put(sock);
726
727 return 0;
728
729 error:
730 /* Put UDP header back */
731 __skb_push(skb, sizeof(struct udphdr));
732 sock_put(sock);
733
734 no_tunnel:
735 return 1;
736 }
737
738 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
739 * Return codes:
740 * 0 : success.
741 * <0: error
742 * >0: skb should be passed up to userspace as UDP.
743 */
744 static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
745 {
746 struct pppol2tp_tunnel *tunnel;
747
748 tunnel = pppol2tp_sock_to_tunnel(sk);
749 if (tunnel == NULL)
750 goto pass_up;
751
752 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
753 "%s: received %d bytes\n", tunnel->name, skb->len);
754
755 if (pppol2tp_recv_core(sk, skb))
756 goto pass_up_put;
757
758 sock_put(sk);
759 return 0;
760
761 pass_up_put:
762 sock_put(sk);
763 pass_up:
764 return 1;
765 }
766
767 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
768 */
769 static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
770 struct msghdr *msg, size_t len,
771 int flags)
772 {
773 int err;
774 struct sk_buff *skb;
775 struct sock *sk = sock->sk;
776
777 err = -EIO;
778 if (sk->sk_state & PPPOX_BOUND)
779 goto end;
780
781 msg->msg_namelen = 0;
782
783 err = 0;
784 skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
785 flags & MSG_DONTWAIT, &err);
786 if (skb) {
787 err = memcpy_toiovec(msg->msg_iov, (unsigned char *) skb->data,
788 skb->len);
789 if (err < 0)
790 goto do_skb_free;
791 err = skb->len;
792 }
793 do_skb_free:
794 kfree_skb(skb);
795 end:
796 return err;
797 }
798
799 /************************************************************************
800 * Transmit handling
801 ***********************************************************************/
802
803 /* Tell how big L2TP headers are for a particular session. This
804 * depends on whether sequence numbers are being used.
805 */
806 static inline int pppol2tp_l2tp_header_len(struct pppol2tp_session *session)
807 {
808 if (session->send_seq)
809 return PPPOL2TP_L2TP_HDR_SIZE_SEQ;
810
811 return PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
812 }
813
814 /* Build an L2TP header for the session into the buffer provided.
815 */
816 static void pppol2tp_build_l2tp_header(struct pppol2tp_session *session,
817 void *buf)
818 {
819 __be16 *bufp = buf;
820 u16 flags = L2TP_HDR_VER;
821
822 if (session->send_seq)
823 flags |= L2TP_HDRFLAG_S;
824
825 /* Setup L2TP header.
826 * FIXME: Can this ever be unaligned? Is direct dereferencing of
827 * 16-bit header fields safe here for all architectures?
828 */
829 *bufp++ = htons(flags);
830 *bufp++ = htons(session->tunnel_addr.d_tunnel);
831 *bufp++ = htons(session->tunnel_addr.d_session);
832 if (session->send_seq) {
833 *bufp++ = htons(session->ns);
834 *bufp++ = 0;
835 session->ns++;
836 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
837 "%s: updated ns to %hu\n", session->name, session->ns);
838 }
839 }
840
841 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket. We come here
842 * when a user application does a sendmsg() on the session socket. L2TP and
843 * PPP headers must be inserted into the user's data.
844 */
845 static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
846 size_t total_len)
847 {
848 static const unsigned char ppph[2] = { 0xff, 0x03 };
849 struct sock *sk = sock->sk;
850 struct inet_sock *inet;
851 __wsum csum = 0;
852 struct sk_buff *skb;
853 int error;
854 int hdr_len;
855 struct pppol2tp_session *session;
856 struct pppol2tp_tunnel *tunnel;
857 struct udphdr *uh;
858 unsigned int len;
859
860 error = -ENOTCONN;
861 if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
862 goto error;
863
864 /* Get session and tunnel contexts */
865 error = -EBADF;
866 session = pppol2tp_sock_to_session(sk);
867 if (session == NULL)
868 goto error;
869
870 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
871 if (tunnel == NULL)
872 goto error_put_sess;
873
874 /* What header length is configured for this session? */
875 hdr_len = pppol2tp_l2tp_header_len(session);
876
877 /* Allocate a socket buffer */
878 error = -ENOMEM;
879 skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
880 sizeof(struct udphdr) + hdr_len +
881 sizeof(ppph) + total_len,
882 0, GFP_KERNEL);
883 if (!skb)
884 goto error_put_sess_tun;
885
886 /* Reserve space for headers. */
887 skb_reserve(skb, NET_SKB_PAD);
888 skb_reset_network_header(skb);
889 skb_reserve(skb, sizeof(struct iphdr));
890 skb_reset_transport_header(skb);
891
892 /* Build UDP header */
893 inet = inet_sk(session->tunnel_sock);
894 uh = (struct udphdr *) skb->data;
895 uh->source = inet->sport;
896 uh->dest = inet->dport;
897 uh->len = htons(hdr_len + sizeof(ppph) + total_len);
898 uh->check = 0;
899 skb_put(skb, sizeof(struct udphdr));
900
901 /* Build L2TP header */
902 pppol2tp_build_l2tp_header(session, skb->data);
903 skb_put(skb, hdr_len);
904
905 /* Add PPP header */
906 skb->data[0] = ppph[0];
907 skb->data[1] = ppph[1];
908 skb_put(skb, 2);
909
910 /* Copy user data into skb */
911 error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
912 if (error < 0) {
913 kfree_skb(skb);
914 goto error_put_sess_tun;
915 }
916 skb_put(skb, total_len);
917
918 /* Calculate UDP checksum if configured to do so */
919 if (session->tunnel_sock->sk_no_check != UDP_CSUM_NOXMIT)
920 csum = udp_csum_outgoing(sk, skb);
921
922 /* Debug */
923 if (session->send_seq)
924 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
925 "%s: send %Zd bytes, ns=%hu\n", session->name,
926 total_len, session->ns - 1);
927 else
928 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
929 "%s: send %Zd bytes\n", session->name, total_len);
930
931 if (session->debug & PPPOL2TP_MSG_DATA) {
932 int i;
933 unsigned char *datap = skb->data;
934
935 printk(KERN_DEBUG "%s: xmit:", session->name);
936 for (i = 0; i < total_len; i++) {
937 printk(" %02X", *datap++);
938 if (i == 15) {
939 printk(" ...");
940 break;
941 }
942 }
943 printk("\n");
944 }
945
946 /* Queue the packet to IP for output */
947 len = skb->len;
948 error = ip_queue_xmit(skb, 1);
949
950 /* Update stats */
951 if (error >= 0) {
952 tunnel->stats.tx_packets++;
953 tunnel->stats.tx_bytes += len;
954 session->stats.tx_packets++;
955 session->stats.tx_bytes += len;
956 } else {
957 tunnel->stats.tx_errors++;
958 session->stats.tx_errors++;
959 }
960
961 return error;
962
963 error_put_sess_tun:
964 sock_put(session->tunnel_sock);
965 error_put_sess:
966 sock_put(sk);
967 error:
968 return error;
969 }
970
971 /* Automatically called when the skb is freed.
972 */
973 static void pppol2tp_sock_wfree(struct sk_buff *skb)
974 {
975 sock_put(skb->sk);
976 }
977
978 /* For data skbs that we transmit, we associate with the tunnel socket
979 * but don't do accounting.
980 */
981 static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
982 {
983 sock_hold(sk);
984 skb->sk = sk;
985 skb->destructor = pppol2tp_sock_wfree;
986 }
987
988 /* Transmit function called by generic PPP driver. Sends PPP frame
989 * over PPPoL2TP socket.
990 *
991 * This is almost the same as pppol2tp_sendmsg(), but rather than
992 * being called with a msghdr from userspace, it is called with a skb
993 * from the kernel.
994 *
995 * The supplied skb from ppp doesn't have enough headroom for the
996 * insertion of L2TP, UDP and IP headers so we need to allocate more
997 * headroom in the skb. This will create a cloned skb. But we must be
998 * careful in the error case because the caller will expect to free
999 * the skb it supplied, not our cloned skb. So we take care to always
1000 * leave the original skb unfreed if we return an error.
1001 */
1002 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
1003 {
1004 static const u8 ppph[2] = { 0xff, 0x03 };
1005 struct sock *sk = (struct sock *) chan->private;
1006 struct sock *sk_tun;
1007 int hdr_len;
1008 struct pppol2tp_session *session;
1009 struct pppol2tp_tunnel *tunnel;
1010 int rc;
1011 int headroom;
1012 int data_len = skb->len;
1013 struct inet_sock *inet;
1014 __wsum csum = 0;
1015 struct udphdr *uh;
1016 unsigned int len;
1017 int old_headroom;
1018 int new_headroom;
1019
1020 if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
1021 goto abort;
1022
1023 /* Get session and tunnel contexts from the socket */
1024 session = pppol2tp_sock_to_session(sk);
1025 if (session == NULL)
1026 goto abort;
1027
1028 sk_tun = session->tunnel_sock;
1029 if (sk_tun == NULL)
1030 goto abort_put_sess;
1031 tunnel = pppol2tp_sock_to_tunnel(sk_tun);
1032 if (tunnel == NULL)
1033 goto abort_put_sess;
1034
1035 /* What header length is configured for this session? */
1036 hdr_len = pppol2tp_l2tp_header_len(session);
1037
1038 /* Check that there's enough headroom in the skb to insert IP,
1039 * UDP and L2TP and PPP headers. If not enough, expand it to
1040 * make room. Adjust truesize.
1041 */
1042 headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1043 sizeof(struct udphdr) + hdr_len + sizeof(ppph);
1044 old_headroom = skb_headroom(skb);
1045 if (skb_cow_head(skb, headroom))
1046 goto abort_put_sess_tun;
1047
1048 new_headroom = skb_headroom(skb);
1049 skb_orphan(skb);
1050 skb->truesize += new_headroom - old_headroom;
1051
1052 /* Setup PPP header */
1053 __skb_push(skb, sizeof(ppph));
1054 skb->data[0] = ppph[0];
1055 skb->data[1] = ppph[1];
1056
1057 /* Setup L2TP header */
1058 pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));
1059
1060 /* Setup UDP header */
1061 inet = inet_sk(sk_tun);
1062 __skb_push(skb, sizeof(*uh));
1063 skb_reset_transport_header(skb);
1064 uh = udp_hdr(skb);
1065 uh->source = inet->sport;
1066 uh->dest = inet->dport;
1067 uh->len = htons(sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len);
1068 uh->check = 0;
1069
1070 /* *BROKEN* Calculate UDP checksum if configured to do so */
1071 if (sk_tun->sk_no_check != UDP_CSUM_NOXMIT)
1072 csum = udp_csum_outgoing(sk_tun, skb);
1073
1074 /* Debug */
1075 if (session->send_seq)
1076 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1077 "%s: send %d bytes, ns=%hu\n", session->name,
1078 data_len, session->ns - 1);
1079 else
1080 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1081 "%s: send %d bytes\n", session->name, data_len);
1082
1083 if (session->debug & PPPOL2TP_MSG_DATA) {
1084 int i;
1085 unsigned char *datap = skb->data;
1086
1087 printk(KERN_DEBUG "%s: xmit:", session->name);
1088 for (i = 0; i < data_len; i++) {
1089 printk(" %02X", *datap++);
1090 if (i == 31) {
1091 printk(" ...");
1092 break;
1093 }
1094 }
1095 printk("\n");
1096 }
1097
1098 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1099 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1100 IPSKB_REROUTED);
1101 nf_reset(skb);
1102
1103 /* Get routing info from the tunnel socket */
1104 dst_release(skb->dst);
1105 skb->dst = dst_clone(__sk_dst_get(sk_tun));
1106 pppol2tp_skb_set_owner_w(skb, sk_tun);
1107
1108 /* Queue the packet to IP for output */
1109 len = skb->len;
1110 rc = ip_queue_xmit(skb, 1);
1111
1112 /* Update stats */
1113 if (rc >= 0) {
1114 tunnel->stats.tx_packets++;
1115 tunnel->stats.tx_bytes += len;
1116 session->stats.tx_packets++;
1117 session->stats.tx_bytes += len;
1118 } else {
1119 tunnel->stats.tx_errors++;
1120 session->stats.tx_errors++;
1121 }
1122
1123 sock_put(sk_tun);
1124 sock_put(sk);
1125 return 1;
1126
1127 abort_put_sess_tun:
1128 sock_put(sk_tun);
1129 abort_put_sess:
1130 sock_put(sk);
1131 abort:
1132 /* Free the original skb */
1133 kfree_skb(skb);
1134 return 1;
1135 }
1136
1137 /*****************************************************************************
1138 * Session (and tunnel control) socket create/destroy.
1139 *****************************************************************************/
1140
1141 /* When the tunnel UDP socket is closed, all the attached sockets need to go
1142 * too.
1143 */
1144 static void pppol2tp_tunnel_closeall(struct pppol2tp_tunnel *tunnel)
1145 {
1146 int hash;
1147 struct hlist_node *walk;
1148 struct hlist_node *tmp;
1149 struct pppol2tp_session *session;
1150 struct sock *sk;
1151
1152 if (tunnel == NULL)
1153 BUG();
1154
1155 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1156 "%s: closing all sessions...\n", tunnel->name);
1157
1158 write_lock_bh(&tunnel->hlist_lock);
1159 for (hash = 0; hash < PPPOL2TP_HASH_SIZE; hash++) {
1160 again:
1161 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1162 struct sk_buff *skb;
1163
1164 session = hlist_entry(walk, struct pppol2tp_session, hlist);
1165
1166 sk = session->sock;
1167
1168 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1169 "%s: closing session\n", session->name);
1170
1171 hlist_del_init(&session->hlist);
1172
1173 /* Since we should hold the sock lock while
1174 * doing any unbinding, we need to release the
1175 * lock we're holding before taking that lock.
1176 * Hold a reference to the sock so it doesn't
1177 * disappear as we're jumping between locks.
1178 */
1179 sock_hold(sk);
1180 write_unlock_bh(&tunnel->hlist_lock);
1181 lock_sock(sk);
1182
1183 if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
1184 pppox_unbind_sock(sk);
1185 sk->sk_state = PPPOX_DEAD;
1186 sk->sk_state_change(sk);
1187 }
1188
1189 /* Purge any queued data */
1190 skb_queue_purge(&sk->sk_receive_queue);
1191 skb_queue_purge(&sk->sk_write_queue);
1192 while ((skb = skb_dequeue(&session->reorder_q))) {
1193 kfree_skb(skb);
1194 sock_put(sk);
1195 }
1196
1197 release_sock(sk);
1198 sock_put(sk);
1199
1200 /* Now restart from the beginning of this hash
1201 * chain. We always remove a session from the
1202 * list so we are guaranteed to make forward
1203 * progress.
1204 */
1205 write_lock_bh(&tunnel->hlist_lock);
1206 goto again;
1207 }
1208 }
1209 write_unlock_bh(&tunnel->hlist_lock);
1210 }
1211
1212 /* Really kill the tunnel.
1213 * Come here only when all sessions have been cleared from the tunnel.
1214 */
1215 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel)
1216 {
1217 /* Remove from socket list */
1218 write_lock_bh(&pppol2tp_tunnel_list_lock);
1219 list_del_init(&tunnel->list);
1220 write_unlock_bh(&pppol2tp_tunnel_list_lock);
1221
1222 atomic_dec(&pppol2tp_tunnel_count);
1223 kfree(tunnel);
1224 }
1225
1226 /* Tunnel UDP socket destruct hook.
1227 * The tunnel context is deleted only when all session sockets have been
1228 * closed.
1229 */
1230 static void pppol2tp_tunnel_destruct(struct sock *sk)
1231 {
1232 struct pppol2tp_tunnel *tunnel;
1233
1234 tunnel = sk->sk_user_data;
1235 if (tunnel == NULL)
1236 goto end;
1237
1238 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1239 "%s: closing...\n", tunnel->name);
1240
1241 /* Close all sessions */
1242 pppol2tp_tunnel_closeall(tunnel);
1243
1244 /* No longer an encapsulation socket. See net/ipv4/udp.c */
1245 (udp_sk(sk))->encap_type = 0;
1246 (udp_sk(sk))->encap_rcv = NULL;
1247
1248 /* Remove hooks into tunnel socket */
1249 tunnel->sock = NULL;
1250 sk->sk_destruct = tunnel->old_sk_destruct;
1251 sk->sk_user_data = NULL;
1252
1253 /* Call original (UDP) socket descructor */
1254 if (sk->sk_destruct != NULL)
1255 (*sk->sk_destruct)(sk);
1256
1257 pppol2tp_tunnel_dec_refcount(tunnel);
1258
1259 end:
1260 return;
1261 }
1262
1263 /* Really kill the session socket. (Called from sock_put() if
1264 * refcnt == 0.)
1265 */
1266 static void pppol2tp_session_destruct(struct sock *sk)
1267 {
1268 struct pppol2tp_session *session = NULL;
1269
1270 if (sk->sk_user_data != NULL) {
1271 struct pppol2tp_tunnel *tunnel;
1272
1273 session = sk->sk_user_data;
1274 if (session == NULL)
1275 goto out;
1276
1277 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
1278
1279 /* Don't use pppol2tp_sock_to_tunnel() here to
1280 * get the tunnel context because the tunnel
1281 * socket might have already been closed (its
1282 * sk->sk_user_data will be NULL) so use the
1283 * session's private tunnel ptr instead.
1284 */
1285 tunnel = session->tunnel;
1286 if (tunnel != NULL) {
1287 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1288
1289 /* If session_id is zero, this is a null
1290 * session context, which was created for a
1291 * socket that is being used only to manage
1292 * tunnels.
1293 */
1294 if (session->tunnel_addr.s_session != 0) {
1295 /* Delete the session socket from the
1296 * hash
1297 */
1298 write_lock_bh(&tunnel->hlist_lock);
1299 hlist_del_init(&session->hlist);
1300 write_unlock_bh(&tunnel->hlist_lock);
1301
1302 atomic_dec(&pppol2tp_session_count);
1303 }
1304
1305 /* This will delete the tunnel context if this
1306 * is the last session on the tunnel.
1307 */
1308 session->tunnel = NULL;
1309 session->tunnel_sock = NULL;
1310 pppol2tp_tunnel_dec_refcount(tunnel);
1311 }
1312 }
1313
1314 kfree(session);
1315 out:
1316 return;
1317 }
1318
1319 /* Called when the PPPoX socket (session) is closed.
1320 */
1321 static int pppol2tp_release(struct socket *sock)
1322 {
1323 struct sock *sk = sock->sk;
1324 struct pppol2tp_session *session;
1325 int error;
1326
1327 if (!sk)
1328 return 0;
1329
1330 error = -EBADF;
1331 lock_sock(sk);
1332 if (sock_flag(sk, SOCK_DEAD) != 0)
1333 goto error;
1334
1335 pppox_unbind_sock(sk);
1336
1337 /* Signal the death of the socket. */
1338 sk->sk_state = PPPOX_DEAD;
1339 sock_orphan(sk);
1340 sock->sk = NULL;
1341
1342 session = pppol2tp_sock_to_session(sk);
1343
1344 /* Purge any queued data */
1345 skb_queue_purge(&sk->sk_receive_queue);
1346 skb_queue_purge(&sk->sk_write_queue);
1347 if (session != NULL) {
1348 struct sk_buff *skb;
1349 while ((skb = skb_dequeue(&session->reorder_q))) {
1350 kfree_skb(skb);
1351 sock_put(sk);
1352 }
1353 }
1354
1355 release_sock(sk);
1356
1357 /* This will delete the session context via
1358 * pppol2tp_session_destruct() if the socket's refcnt drops to
1359 * zero.
1360 */
1361 sock_put(sk);
1362
1363 return 0;
1364
1365 error:
1366 release_sock(sk);
1367 return error;
1368 }
1369
1370 /* Internal function to prepare a tunnel (UDP) socket to have PPPoX
1371 * sockets attached to it.
1372 */
1373 static struct sock *pppol2tp_prepare_tunnel_socket(int fd, u16 tunnel_id,
1374 int *error)
1375 {
1376 int err;
1377 struct socket *sock = NULL;
1378 struct sock *sk;
1379 struct pppol2tp_tunnel *tunnel;
1380 struct sock *ret = NULL;
1381
1382 /* Get the tunnel UDP socket from the fd, which was opened by
1383 * the userspace L2TP daemon.
1384 */
1385 err = -EBADF;
1386 sock = sockfd_lookup(fd, &err);
1387 if (!sock) {
1388 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1389 "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1390 tunnel_id, fd, err);
1391 goto err;
1392 }
1393
1394 sk = sock->sk;
1395
1396 /* Quick sanity checks */
1397 err = -EPROTONOSUPPORT;
1398 if (sk->sk_protocol != IPPROTO_UDP) {
1399 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1400 "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1401 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1402 goto err;
1403 }
1404 err = -EAFNOSUPPORT;
1405 if (sock->ops->family != AF_INET) {
1406 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1407 "tunl %hu: fd %d wrong family, got %d, expected %d\n",
1408 tunnel_id, fd, sock->ops->family, AF_INET);
1409 goto err;
1410 }
1411
1412 err = -ENOTCONN;
1413
1414 /* Check if this socket has already been prepped */
1415 tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data;
1416 if (tunnel != NULL) {
1417 /* User-data field already set */
1418 err = -EBUSY;
1419 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1420
1421 /* This socket has already been prepped */
1422 ret = tunnel->sock;
1423 goto out;
1424 }
1425
1426 /* This socket is available and needs prepping. Create a new tunnel
1427 * context and init it.
1428 */
1429 sk->sk_user_data = tunnel = kzalloc(sizeof(struct pppol2tp_tunnel), GFP_KERNEL);
1430 if (sk->sk_user_data == NULL) {
1431 err = -ENOMEM;
1432 goto err;
1433 }
1434
1435 tunnel->magic = L2TP_TUNNEL_MAGIC;
1436 sprintf(&tunnel->name[0], "tunl %hu", tunnel_id);
1437
1438 tunnel->stats.tunnel_id = tunnel_id;
1439 tunnel->debug = PPPOL2TP_DEFAULT_DEBUG_FLAGS;
1440
1441 /* Hook on the tunnel socket destructor so that we can cleanup
1442 * if the tunnel socket goes away.
1443 */
1444 tunnel->old_sk_destruct = sk->sk_destruct;
1445 sk->sk_destruct = &pppol2tp_tunnel_destruct;
1446
1447 tunnel->sock = sk;
1448 sk->sk_allocation = GFP_ATOMIC;
1449
1450 /* Misc init */
1451 rwlock_init(&tunnel->hlist_lock);
1452
1453 /* Add tunnel to our list */
1454 INIT_LIST_HEAD(&tunnel->list);
1455 write_lock_bh(&pppol2tp_tunnel_list_lock);
1456 list_add(&tunnel->list, &pppol2tp_tunnel_list);
1457 write_unlock_bh(&pppol2tp_tunnel_list_lock);
1458 atomic_inc(&pppol2tp_tunnel_count);
1459
1460 /* Bump the reference count. The tunnel context is deleted
1461 * only when this drops to zero.
1462 */
1463 pppol2tp_tunnel_inc_refcount(tunnel);
1464
1465 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1466 (udp_sk(sk))->encap_type = UDP_ENCAP_L2TPINUDP;
1467 (udp_sk(sk))->encap_rcv = pppol2tp_udp_encap_recv;
1468
1469 ret = tunnel->sock;
1470
1471 *error = 0;
1472 out:
1473 if (sock)
1474 sockfd_put(sock);
1475
1476 return ret;
1477
1478 err:
1479 *error = err;
1480 goto out;
1481 }
1482
1483 static struct proto pppol2tp_sk_proto = {
1484 .name = "PPPOL2TP",
1485 .owner = THIS_MODULE,
1486 .obj_size = sizeof(struct pppox_sock),
1487 };
1488
1489 /* socket() handler. Initialize a new struct sock.
1490 */
1491 static int pppol2tp_create(struct net *net, struct socket *sock)
1492 {
1493 int error = -ENOMEM;
1494 struct sock *sk;
1495
1496 sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
1497 if (!sk)
1498 goto out;
1499
1500 sock_init_data(sock, sk);
1501
1502 sock->state = SS_UNCONNECTED;
1503 sock->ops = &pppol2tp_ops;
1504
1505 sk->sk_backlog_rcv = pppol2tp_recv_core;
1506 sk->sk_protocol = PX_PROTO_OL2TP;
1507 sk->sk_family = PF_PPPOX;
1508 sk->sk_state = PPPOX_NONE;
1509 sk->sk_type = SOCK_STREAM;
1510 sk->sk_destruct = pppol2tp_session_destruct;
1511
1512 error = 0;
1513
1514 out:
1515 return error;
1516 }
1517
1518 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
1519 */
1520 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
1521 int sockaddr_len, int flags)
1522 {
1523 struct sock *sk = sock->sk;
1524 struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
1525 struct pppox_sock *po = pppox_sk(sk);
1526 struct sock *tunnel_sock = NULL;
1527 struct pppol2tp_session *session = NULL;
1528 struct pppol2tp_tunnel *tunnel;
1529 struct dst_entry *dst;
1530 int error = 0;
1531
1532 lock_sock(sk);
1533
1534 error = -EINVAL;
1535 if (sp->sa_protocol != PX_PROTO_OL2TP)
1536 goto end;
1537
1538 /* Check for already bound sockets */
1539 error = -EBUSY;
1540 if (sk->sk_state & PPPOX_CONNECTED)
1541 goto end;
1542
1543 /* We don't supporting rebinding anyway */
1544 error = -EALREADY;
1545 if (sk->sk_user_data)
1546 goto end; /* socket is already attached */
1547
1548 /* Don't bind if s_tunnel is 0 */
1549 error = -EINVAL;
1550 if (sp->pppol2tp.s_tunnel == 0)
1551 goto end;
1552
1553 /* Special case: prepare tunnel socket if s_session and
1554 * d_session is 0. Otherwise look up tunnel using supplied
1555 * tunnel id.
1556 */
1557 if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) {
1558 tunnel_sock = pppol2tp_prepare_tunnel_socket(sp->pppol2tp.fd,
1559 sp->pppol2tp.s_tunnel,
1560 &error);
1561 if (tunnel_sock == NULL)
1562 goto end;
1563
1564 tunnel = tunnel_sock->sk_user_data;
1565 } else {
1566 tunnel = pppol2tp_tunnel_find(sp->pppol2tp.s_tunnel);
1567
1568 /* Error if we can't find the tunnel */
1569 error = -ENOENT;
1570 if (tunnel == NULL)
1571 goto end;
1572
1573 tunnel_sock = tunnel->sock;
1574 }
1575
1576 /* Check that this session doesn't already exist */
1577 error = -EEXIST;
1578 session = pppol2tp_session_find(tunnel, sp->pppol2tp.s_session);
1579 if (session != NULL)
1580 goto end;
1581
1582 /* Allocate and initialize a new session context. */
1583 session = kzalloc(sizeof(struct pppol2tp_session), GFP_KERNEL);
1584 if (session == NULL) {
1585 error = -ENOMEM;
1586 goto end;
1587 }
1588
1589 skb_queue_head_init(&session->reorder_q);
1590
1591 session->magic = L2TP_SESSION_MAGIC;
1592 session->owner = current->pid;
1593 session->sock = sk;
1594 session->tunnel = tunnel;
1595 session->tunnel_sock = tunnel_sock;
1596 session->tunnel_addr = sp->pppol2tp;
1597 sprintf(&session->name[0], "sess %hu/%hu",
1598 session->tunnel_addr.s_tunnel,
1599 session->tunnel_addr.s_session);
1600
1601 session->stats.tunnel_id = session->tunnel_addr.s_tunnel;
1602 session->stats.session_id = session->tunnel_addr.s_session;
1603
1604 INIT_HLIST_NODE(&session->hlist);
1605
1606 /* Inherit debug options from tunnel */
1607 session->debug = tunnel->debug;
1608
1609 /* Default MTU must allow space for UDP/L2TP/PPP
1610 * headers.
1611 */
1612 session->mtu = session->mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
1613
1614 /* If PMTU discovery was enabled, use the MTU that was discovered */
1615 dst = sk_dst_get(sk);
1616 if (dst != NULL) {
1617 u32 pmtu = dst_mtu(__sk_dst_get(sk));
1618 if (pmtu != 0)
1619 session->mtu = session->mru = pmtu -
1620 PPPOL2TP_HEADER_OVERHEAD;
1621 dst_release(dst);
1622 }
1623
1624 /* Special case: if source & dest session_id == 0x0000, this socket is
1625 * being created to manage the tunnel. Don't add the session to the
1626 * session hash list, just set up the internal context for use by
1627 * ioctl() and sockopt() handlers.
1628 */
1629 if ((session->tunnel_addr.s_session == 0) &&
1630 (session->tunnel_addr.d_session == 0)) {
1631 error = 0;
1632 sk->sk_user_data = session;
1633 goto out_no_ppp;
1634 }
1635
1636 /* Get tunnel context from the tunnel socket */
1637 tunnel = pppol2tp_sock_to_tunnel(tunnel_sock);
1638 if (tunnel == NULL) {
1639 error = -EBADF;
1640 goto end;
1641 }
1642
1643 /* Right now, because we don't have a way to push the incoming skb's
1644 * straight through the UDP layer, the only header we need to worry
1645 * about is the L2TP header. This size is different depending on
1646 * whether sequence numbers are enabled for the data channel.
1647 */
1648 po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1649
1650 po->chan.private = sk;
1651 po->chan.ops = &pppol2tp_chan_ops;
1652 po->chan.mtu = session->mtu;
1653
1654 error = ppp_register_channel(&po->chan);
1655 if (error)
1656 goto end_put_tun;
1657
1658 /* This is how we get the session context from the socket. */
1659 sk->sk_user_data = session;
1660
1661 /* Add session to the tunnel's hash list */
1662 write_lock_bh(&tunnel->hlist_lock);
1663 hlist_add_head(&session->hlist,
1664 pppol2tp_session_id_hash(tunnel,
1665 session->tunnel_addr.s_session));
1666 write_unlock_bh(&tunnel->hlist_lock);
1667
1668 atomic_inc(&pppol2tp_session_count);
1669
1670 out_no_ppp:
1671 pppol2tp_tunnel_inc_refcount(tunnel);
1672 sk->sk_state = PPPOX_CONNECTED;
1673 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1674 "%s: created\n", session->name);
1675
1676 end_put_tun:
1677 sock_put(tunnel_sock);
1678 end:
1679 release_sock(sk);
1680
1681 if (error != 0)
1682 PRINTK(session ? session->debug : -1, PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1683 "%s: connect failed: %d\n", session->name, error);
1684
1685 return error;
1686 }
1687
1688 /* getname() support.
1689 */
1690 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
1691 int *usockaddr_len, int peer)
1692 {
1693 int len = sizeof(struct sockaddr_pppol2tp);
1694 struct sockaddr_pppol2tp sp;
1695 int error = 0;
1696 struct pppol2tp_session *session;
1697
1698 error = -ENOTCONN;
1699 if (sock->sk->sk_state != PPPOX_CONNECTED)
1700 goto end;
1701
1702 session = pppol2tp_sock_to_session(sock->sk);
1703 if (session == NULL) {
1704 error = -EBADF;
1705 goto end;
1706 }
1707
1708 sp.sa_family = AF_PPPOX;
1709 sp.sa_protocol = PX_PROTO_OL2TP;
1710 memcpy(&sp.pppol2tp, &session->tunnel_addr,
1711 sizeof(struct pppol2tp_addr));
1712
1713 memcpy(uaddr, &sp, len);
1714
1715 *usockaddr_len = len;
1716
1717 error = 0;
1718 sock_put(sock->sk);
1719
1720 end:
1721 return error;
1722 }
1723
1724 /****************************************************************************
1725 * ioctl() handlers.
1726 *
1727 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1728 * sockets. However, in order to control kernel tunnel features, we allow
1729 * userspace to create a special "tunnel" PPPoX socket which is used for
1730 * control only. Tunnel PPPoX sockets have session_id == 0 and simply allow
1731 * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1732 * calls.
1733 ****************************************************************************/
1734
1735 /* Session ioctl helper.
1736 */
1737 static int pppol2tp_session_ioctl(struct pppol2tp_session *session,
1738 unsigned int cmd, unsigned long arg)
1739 {
1740 struct ifreq ifr;
1741 int err = 0;
1742 struct sock *sk = session->sock;
1743 int val = (int) arg;
1744
1745 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1746 "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
1747 session->name, cmd, arg);
1748
1749 sock_hold(sk);
1750
1751 switch (cmd) {
1752 case SIOCGIFMTU:
1753 err = -ENXIO;
1754 if (!(sk->sk_state & PPPOX_CONNECTED))
1755 break;
1756
1757 err = -EFAULT;
1758 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1759 break;
1760 ifr.ifr_mtu = session->mtu;
1761 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1762 break;
1763
1764 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1765 "%s: get mtu=%d\n", session->name, session->mtu);
1766 err = 0;
1767 break;
1768
1769 case SIOCSIFMTU:
1770 err = -ENXIO;
1771 if (!(sk->sk_state & PPPOX_CONNECTED))
1772 break;
1773
1774 err = -EFAULT;
1775 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1776 break;
1777
1778 session->mtu = ifr.ifr_mtu;
1779
1780 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1781 "%s: set mtu=%d\n", session->name, session->mtu);
1782 err = 0;
1783 break;
1784
1785 case PPPIOCGMRU:
1786 err = -ENXIO;
1787 if (!(sk->sk_state & PPPOX_CONNECTED))
1788 break;
1789
1790 err = -EFAULT;
1791 if (put_user(session->mru, (int __user *) arg))
1792 break;
1793
1794 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1795 "%s: get mru=%d\n", session->name, session->mru);
1796 err = 0;
1797 break;
1798
1799 case PPPIOCSMRU:
1800 err = -ENXIO;
1801 if (!(sk->sk_state & PPPOX_CONNECTED))
1802 break;
1803
1804 err = -EFAULT;
1805 if (get_user(val,(int __user *) arg))
1806 break;
1807
1808 session->mru = val;
1809 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1810 "%s: set mru=%d\n", session->name, session->mru);
1811 err = 0;
1812 break;
1813
1814 case PPPIOCGFLAGS:
1815 err = -EFAULT;
1816 if (put_user(session->flags, (int __user *) arg))
1817 break;
1818
1819 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1820 "%s: get flags=%d\n", session->name, session->flags);
1821 err = 0;
1822 break;
1823
1824 case PPPIOCSFLAGS:
1825 err = -EFAULT;
1826 if (get_user(val, (int __user *) arg))
1827 break;
1828 session->flags = val;
1829 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1830 "%s: set flags=%d\n", session->name, session->flags);
1831 err = 0;
1832 break;
1833
1834 case PPPIOCGL2TPSTATS:
1835 err = -ENXIO;
1836 if (!(sk->sk_state & PPPOX_CONNECTED))
1837 break;
1838
1839 if (copy_to_user((void __user *) arg, &session->stats,
1840 sizeof(session->stats)))
1841 break;
1842 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1843 "%s: get L2TP stats\n", session->name);
1844 err = 0;
1845 break;
1846
1847 default:
1848 err = -ENOSYS;
1849 break;
1850 }
1851
1852 sock_put(sk);
1853
1854 return err;
1855 }
1856
1857 /* Tunnel ioctl helper.
1858 *
1859 * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1860 * specifies a session_id, the session ioctl handler is called. This allows an
1861 * application to retrieve session stats via a tunnel socket.
1862 */
1863 static int pppol2tp_tunnel_ioctl(struct pppol2tp_tunnel *tunnel,
1864 unsigned int cmd, unsigned long arg)
1865 {
1866 int err = 0;
1867 struct sock *sk = tunnel->sock;
1868 struct pppol2tp_ioc_stats stats_req;
1869
1870 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1871 "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n", tunnel->name,
1872 cmd, arg);
1873
1874 sock_hold(sk);
1875
1876 switch (cmd) {
1877 case PPPIOCGL2TPSTATS:
1878 err = -ENXIO;
1879 if (!(sk->sk_state & PPPOX_CONNECTED))
1880 break;
1881
1882 if (copy_from_user(&stats_req, (void __user *) arg,
1883 sizeof(stats_req))) {
1884 err = -EFAULT;
1885 break;
1886 }
1887 if (stats_req.session_id != 0) {
1888 /* resend to session ioctl handler */
1889 struct pppol2tp_session *session =
1890 pppol2tp_session_find(tunnel, stats_req.session_id);
1891 if (session != NULL)
1892 err = pppol2tp_session_ioctl(session, cmd, arg);
1893 else
1894 err = -EBADR;
1895 break;
1896 }
1897 #ifdef CONFIG_XFRM
1898 tunnel->stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
1899 #endif
1900 if (copy_to_user((void __user *) arg, &tunnel->stats,
1901 sizeof(tunnel->stats))) {
1902 err = -EFAULT;
1903 break;
1904 }
1905 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1906 "%s: get L2TP stats\n", tunnel->name);
1907 err = 0;
1908 break;
1909
1910 default:
1911 err = -ENOSYS;
1912 break;
1913 }
1914
1915 sock_put(sk);
1916
1917 return err;
1918 }
1919
1920 /* Main ioctl() handler.
1921 * Dispatch to tunnel or session helpers depending on the socket.
1922 */
1923 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1924 unsigned long arg)
1925 {
1926 struct sock *sk = sock->sk;
1927 struct pppol2tp_session *session;
1928 struct pppol2tp_tunnel *tunnel;
1929 int err;
1930
1931 if (!sk)
1932 return 0;
1933
1934 err = -EBADF;
1935 if (sock_flag(sk, SOCK_DEAD) != 0)
1936 goto end;
1937
1938 err = -ENOTCONN;
1939 if ((sk->sk_user_data == NULL) ||
1940 (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
1941 goto end;
1942
1943 /* Get session context from the socket */
1944 err = -EBADF;
1945 session = pppol2tp_sock_to_session(sk);
1946 if (session == NULL)
1947 goto end;
1948
1949 /* Special case: if session's session_id is zero, treat ioctl as a
1950 * tunnel ioctl
1951 */
1952 if ((session->tunnel_addr.s_session == 0) &&
1953 (session->tunnel_addr.d_session == 0)) {
1954 err = -EBADF;
1955 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
1956 if (tunnel == NULL)
1957 goto end_put_sess;
1958
1959 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
1960 sock_put(session->tunnel_sock);
1961 goto end_put_sess;
1962 }
1963
1964 err = pppol2tp_session_ioctl(session, cmd, arg);
1965
1966 end_put_sess:
1967 sock_put(sk);
1968 end:
1969 return err;
1970 }
1971
1972 /*****************************************************************************
1973 * setsockopt() / getsockopt() support.
1974 *
1975 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1976 * sockets. In order to control kernel tunnel features, we allow userspace to
1977 * create a special "tunnel" PPPoX socket which is used for control only.
1978 * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1979 * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1980 *****************************************************************************/
1981
1982 /* Tunnel setsockopt() helper.
1983 */
1984 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1985 struct pppol2tp_tunnel *tunnel,
1986 int optname, int val)
1987 {
1988 int err = 0;
1989
1990 switch (optname) {
1991 case PPPOL2TP_SO_DEBUG:
1992 tunnel->debug = val;
1993 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1994 "%s: set debug=%x\n", tunnel->name, tunnel->debug);
1995 break;
1996
1997 default:
1998 err = -ENOPROTOOPT;
1999 break;
2000 }
2001
2002 return err;
2003 }
2004
2005 /* Session setsockopt helper.
2006 */
2007 static int pppol2tp_session_setsockopt(struct sock *sk,
2008 struct pppol2tp_session *session,
2009 int optname, int val)
2010 {
2011 int err = 0;
2012
2013 switch (optname) {
2014 case PPPOL2TP_SO_RECVSEQ:
2015 if ((val != 0) && (val != 1)) {
2016 err = -EINVAL;
2017 break;
2018 }
2019 session->recv_seq = val ? -1 : 0;
2020 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2021 "%s: set recv_seq=%d\n", session->name,
2022 session->recv_seq);
2023 break;
2024
2025 case PPPOL2TP_SO_SENDSEQ:
2026 if ((val != 0) && (val != 1)) {
2027 err = -EINVAL;
2028 break;
2029 }
2030 session->send_seq = val ? -1 : 0;
2031 {
2032 struct sock *ssk = session->sock;
2033 struct pppox_sock *po = pppox_sk(ssk);
2034 po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
2035 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
2036 }
2037 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2038 "%s: set send_seq=%d\n", session->name, session->send_seq);
2039 break;
2040
2041 case PPPOL2TP_SO_LNSMODE:
2042 if ((val != 0) && (val != 1)) {
2043 err = -EINVAL;
2044 break;
2045 }
2046 session->lns_mode = val ? -1 : 0;
2047 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2048 "%s: set lns_mode=%d\n", session->name,
2049 session->lns_mode);
2050 break;
2051
2052 case PPPOL2TP_SO_DEBUG:
2053 session->debug = val;
2054 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2055 "%s: set debug=%x\n", session->name, session->debug);
2056 break;
2057
2058 case PPPOL2TP_SO_REORDERTO:
2059 session->reorder_timeout = msecs_to_jiffies(val);
2060 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2061 "%s: set reorder_timeout=%d\n", session->name,
2062 session->reorder_timeout);
2063 break;
2064
2065 default:
2066 err = -ENOPROTOOPT;
2067 break;
2068 }
2069
2070 return err;
2071 }
2072
2073 /* Main setsockopt() entry point.
2074 * Does API checks, then calls either the tunnel or session setsockopt
2075 * handler, according to whether the PPPoL2TP socket is a for a regular
2076 * session or the special tunnel type.
2077 */
2078 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
2079 char __user *optval, int optlen)
2080 {
2081 struct sock *sk = sock->sk;
2082 struct pppol2tp_session *session = sk->sk_user_data;
2083 struct pppol2tp_tunnel *tunnel;
2084 int val;
2085 int err;
2086
2087 if (level != SOL_PPPOL2TP)
2088 return udp_prot.setsockopt(sk, level, optname, optval, optlen);
2089
2090 if (optlen < sizeof(int))
2091 return -EINVAL;
2092
2093 if (get_user(val, (int __user *)optval))
2094 return -EFAULT;
2095
2096 err = -ENOTCONN;
2097 if (sk->sk_user_data == NULL)
2098 goto end;
2099
2100 /* Get session context from the socket */
2101 err = -EBADF;
2102 session = pppol2tp_sock_to_session(sk);
2103 if (session == NULL)
2104 goto end;
2105
2106 /* Special case: if session_id == 0x0000, treat as operation on tunnel
2107 */
2108 if ((session->tunnel_addr.s_session == 0) &&
2109 (session->tunnel_addr.d_session == 0)) {
2110 err = -EBADF;
2111 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2112 if (tunnel == NULL)
2113 goto end_put_sess;
2114
2115 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
2116 sock_put(session->tunnel_sock);
2117 } else
2118 err = pppol2tp_session_setsockopt(sk, session, optname, val);
2119
2120 err = 0;
2121
2122 end_put_sess:
2123 sock_put(sk);
2124 end:
2125 return err;
2126 }
2127
2128 /* Tunnel getsockopt helper. Called with sock locked.
2129 */
2130 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
2131 struct pppol2tp_tunnel *tunnel,
2132 int optname, int *val)
2133 {
2134 int err = 0;
2135
2136 switch (optname) {
2137 case PPPOL2TP_SO_DEBUG:
2138 *val = tunnel->debug;
2139 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2140 "%s: get debug=%x\n", tunnel->name, tunnel->debug);
2141 break;
2142
2143 default:
2144 err = -ENOPROTOOPT;
2145 break;
2146 }
2147
2148 return err;
2149 }
2150
2151 /* Session getsockopt helper. Called with sock locked.
2152 */
2153 static int pppol2tp_session_getsockopt(struct sock *sk,
2154 struct pppol2tp_session *session,
2155 int optname, int *val)
2156 {
2157 int err = 0;
2158
2159 switch (optname) {
2160 case PPPOL2TP_SO_RECVSEQ:
2161 *val = session->recv_seq;
2162 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2163 "%s: get recv_seq=%d\n", session->name, *val);
2164 break;
2165
2166 case PPPOL2TP_SO_SENDSEQ:
2167 *val = session->send_seq;
2168 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2169 "%s: get send_seq=%d\n", session->name, *val);
2170 break;
2171
2172 case PPPOL2TP_SO_LNSMODE:
2173 *val = session->lns_mode;
2174 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2175 "%s: get lns_mode=%d\n", session->name, *val);
2176 break;
2177
2178 case PPPOL2TP_SO_DEBUG:
2179 *val = session->debug;
2180 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2181 "%s: get debug=%d\n", session->name, *val);
2182 break;
2183
2184 case PPPOL2TP_SO_REORDERTO:
2185 *val = (int) jiffies_to_msecs(session->reorder_timeout);
2186 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2187 "%s: get reorder_timeout=%d\n", session->name, *val);
2188 break;
2189
2190 default:
2191 err = -ENOPROTOOPT;
2192 }
2193
2194 return err;
2195 }
2196
2197 /* Main getsockopt() entry point.
2198 * Does API checks, then calls either the tunnel or session getsockopt
2199 * handler, according to whether the PPPoX socket is a for a regular session
2200 * or the special tunnel type.
2201 */
2202 static int pppol2tp_getsockopt(struct socket *sock, int level,
2203 int optname, char __user *optval, int __user *optlen)
2204 {
2205 struct sock *sk = sock->sk;
2206 struct pppol2tp_session *session = sk->sk_user_data;
2207 struct pppol2tp_tunnel *tunnel;
2208 int val, len;
2209 int err;
2210
2211 if (level != SOL_PPPOL2TP)
2212 return udp_prot.getsockopt(sk, level, optname, optval, optlen);
2213
2214 if (get_user(len, (int __user *) optlen))
2215 return -EFAULT;
2216
2217 len = min_t(unsigned int, len, sizeof(int));
2218
2219 if (len < 0)
2220 return -EINVAL;
2221
2222 err = -ENOTCONN;
2223 if (sk->sk_user_data == NULL)
2224 goto end;
2225
2226 /* Get the session context */
2227 err = -EBADF;
2228 session = pppol2tp_sock_to_session(sk);
2229 if (session == NULL)
2230 goto end;
2231
2232 /* Special case: if session_id == 0x0000, treat as operation on tunnel */
2233 if ((session->tunnel_addr.s_session == 0) &&
2234 (session->tunnel_addr.d_session == 0)) {
2235 err = -EBADF;
2236 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2237 if (tunnel == NULL)
2238 goto end_put_sess;
2239
2240 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
2241 sock_put(session->tunnel_sock);
2242 } else
2243 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
2244
2245 err = -EFAULT;
2246 if (put_user(len, (int __user *) optlen))
2247 goto end_put_sess;
2248
2249 if (copy_to_user((void __user *) optval, &val, len))
2250 goto end_put_sess;
2251
2252 err = 0;
2253
2254 end_put_sess:
2255 sock_put(sk);
2256 end:
2257 return err;
2258 }
2259
2260 /*****************************************************************************
2261 * /proc filesystem for debug
2262 *****************************************************************************/
2263
2264 #ifdef CONFIG_PROC_FS
2265
2266 #include <linux/seq_file.h>
2267
2268 struct pppol2tp_seq_data {
2269 struct pppol2tp_tunnel *tunnel; /* current tunnel */
2270 struct pppol2tp_session *session; /* NULL means get first session in tunnel */
2271 };
2272
2273 static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr)
2274 {
2275 struct pppol2tp_session *session = NULL;
2276 struct hlist_node *walk;
2277 int found = 0;
2278 int next = 0;
2279 int i;
2280
2281 read_lock_bh(&tunnel->hlist_lock);
2282 for (i = 0; i < PPPOL2TP_HASH_SIZE; i++) {
2283 hlist_for_each_entry(session, walk, &tunnel->session_hlist[i], hlist) {
2284 if (curr == NULL) {
2285 found = 1;
2286 goto out;
2287 }
2288 if (session == curr) {
2289 next = 1;
2290 continue;
2291 }
2292 if (next) {
2293 found = 1;
2294 goto out;
2295 }
2296 }
2297 }
2298 out:
2299 read_unlock_bh(&tunnel->hlist_lock);
2300 if (!found)
2301 session = NULL;
2302
2303 return session;
2304 }
2305
2306 static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_tunnel *curr)
2307 {
2308 struct pppol2tp_tunnel *tunnel = NULL;
2309
2310 read_lock_bh(&pppol2tp_tunnel_list_lock);
2311 if (list_is_last(&curr->list, &pppol2tp_tunnel_list)) {
2312 goto out;
2313 }
2314 tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list);
2315 out:
2316 read_unlock_bh(&pppol2tp_tunnel_list_lock);
2317
2318 return tunnel;
2319 }
2320
2321 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
2322 {
2323 struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
2324 loff_t pos = *offs;
2325
2326 if (!pos)
2327 goto out;
2328
2329 BUG_ON(m->private == NULL);
2330 pd = m->private;
2331
2332 if (pd->tunnel == NULL) {
2333 if (!list_empty(&pppol2tp_tunnel_list))
2334 pd->tunnel = list_entry(pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
2335 } else {
2336 pd->session = next_session(pd->tunnel, pd->session);
2337 if (pd->session == NULL) {
2338 pd->tunnel = next_tunnel(pd->tunnel);
2339 }
2340 }
2341
2342 /* NULL tunnel and session indicates end of list */
2343 if ((pd->tunnel == NULL) && (pd->session == NULL))
2344 pd = NULL;
2345
2346 out:
2347 return pd;
2348 }
2349
2350 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
2351 {
2352 (*pos)++;
2353 return NULL;
2354 }
2355
2356 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
2357 {
2358 /* nothing to do */
2359 }
2360
2361 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
2362 {
2363 struct pppol2tp_tunnel *tunnel = v;
2364
2365 seq_printf(m, "\nTUNNEL '%s', %c %d\n",
2366 tunnel->name,
2367 (tunnel == tunnel->sock->sk_user_data) ? 'Y':'N',
2368 atomic_read(&tunnel->ref_count) - 1);
2369 seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n",
2370 tunnel->debug,
2371 (unsigned long long)tunnel->stats.tx_packets,
2372 (unsigned long long)tunnel->stats.tx_bytes,
2373 (unsigned long long)tunnel->stats.tx_errors,
2374 (unsigned long long)tunnel->stats.rx_packets,
2375 (unsigned long long)tunnel->stats.rx_bytes,
2376 (unsigned long long)tunnel->stats.rx_errors);
2377 }
2378
2379 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
2380 {
2381 struct pppol2tp_session *session = v;
2382
2383 seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> "
2384 "%04X/%04X %d %c\n",
2385 session->name,
2386 ntohl(session->tunnel_addr.addr.sin_addr.s_addr),
2387 ntohs(session->tunnel_addr.addr.sin_port),
2388 session->tunnel_addr.s_tunnel,
2389 session->tunnel_addr.s_session,
2390 session->tunnel_addr.d_tunnel,
2391 session->tunnel_addr.d_session,
2392 session->sock->sk_state,
2393 (session == session->sock->sk_user_data) ?
2394 'Y' : 'N');
2395 seq_printf(m, " %d/%d/%c/%c/%s %08x %u\n",
2396 session->mtu, session->mru,
2397 session->recv_seq ? 'R' : '-',
2398 session->send_seq ? 'S' : '-',
2399 session->lns_mode ? "LNS" : "LAC",
2400 session->debug,
2401 jiffies_to_msecs(session->reorder_timeout));
2402 seq_printf(m, " %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n",
2403 session->nr, session->ns,
2404 (unsigned long long)session->stats.tx_packets,
2405 (unsigned long long)session->stats.tx_bytes,
2406 (unsigned long long)session->stats.tx_errors,
2407 (unsigned long long)session->stats.rx_packets,
2408 (unsigned long long)session->stats.rx_bytes,
2409 (unsigned long long)session->stats.rx_errors);
2410 }
2411
2412 static int pppol2tp_seq_show(struct seq_file *m, void *v)
2413 {
2414 struct pppol2tp_seq_data *pd = v;
2415
2416 /* display header on line 1 */
2417 if (v == SEQ_START_TOKEN) {
2418 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
2419 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
2420 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2421 seq_puts(m, " SESSION name, addr/port src-tid/sid "
2422 "dest-tid/sid state user-data-ok\n");
2423 seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
2424 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2425 goto out;
2426 }
2427
2428 /* Show the tunnel or session context.
2429 */
2430 if (pd->session == NULL)
2431 pppol2tp_seq_tunnel_show(m, pd->tunnel);
2432 else
2433 pppol2tp_seq_session_show(m, pd->session);
2434
2435 out:
2436 return 0;
2437 }
2438
2439 static struct seq_operations pppol2tp_seq_ops = {
2440 .start = pppol2tp_seq_start,
2441 .next = pppol2tp_seq_next,
2442 .stop = pppol2tp_seq_stop,
2443 .show = pppol2tp_seq_show,
2444 };
2445
2446 /* Called when our /proc file is opened. We allocate data for use when
2447 * iterating our tunnel / session contexts and store it in the private
2448 * data of the seq_file.
2449 */
2450 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
2451 {
2452 struct seq_file *m;
2453 struct pppol2tp_seq_data *pd;
2454 int ret = 0;
2455
2456 ret = seq_open(file, &pppol2tp_seq_ops);
2457 if (ret < 0)
2458 goto out;
2459
2460 m = file->private_data;
2461
2462 /* Allocate and fill our proc_data for access later */
2463 ret = -ENOMEM;
2464 m->private = kzalloc(sizeof(struct pppol2tp_seq_data), GFP_KERNEL);
2465 if (m->private == NULL)
2466 goto out;
2467
2468 pd = m->private;
2469 ret = 0;
2470
2471 out:
2472 return ret;
2473 }
2474
2475 /* Called when /proc file access completes.
2476 */
2477 static int pppol2tp_proc_release(struct inode *inode, struct file *file)
2478 {
2479 struct seq_file *m = (struct seq_file *)file->private_data;
2480
2481 kfree(m->private);
2482 m->private = NULL;
2483
2484 return seq_release(inode, file);
2485 }
2486
2487 static struct file_operations pppol2tp_proc_fops = {
2488 .owner = THIS_MODULE,
2489 .open = pppol2tp_proc_open,
2490 .read = seq_read,
2491 .llseek = seq_lseek,
2492 .release = pppol2tp_proc_release,
2493 };
2494
2495 static struct proc_dir_entry *pppol2tp_proc;
2496
2497 #endif /* CONFIG_PROC_FS */
2498
2499 /*****************************************************************************
2500 * Init and cleanup
2501 *****************************************************************************/
2502
2503 static struct proto_ops pppol2tp_ops = {
2504 .family = AF_PPPOX,
2505 .owner = THIS_MODULE,
2506 .release = pppol2tp_release,
2507 .bind = sock_no_bind,
2508 .connect = pppol2tp_connect,
2509 .socketpair = sock_no_socketpair,
2510 .accept = sock_no_accept,
2511 .getname = pppol2tp_getname,
2512 .poll = datagram_poll,
2513 .listen = sock_no_listen,
2514 .shutdown = sock_no_shutdown,
2515 .setsockopt = pppol2tp_setsockopt,
2516 .getsockopt = pppol2tp_getsockopt,
2517 .sendmsg = pppol2tp_sendmsg,
2518 .recvmsg = pppol2tp_recvmsg,
2519 .mmap = sock_no_mmap,
2520 .ioctl = pppox_ioctl,
2521 };
2522
2523 static struct pppox_proto pppol2tp_proto = {
2524 .create = pppol2tp_create,
2525 .ioctl = pppol2tp_ioctl
2526 };
2527
2528 static int __init pppol2tp_init(void)
2529 {
2530 int err;
2531
2532 err = proto_register(&pppol2tp_sk_proto, 0);
2533 if (err)
2534 goto out;
2535 err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
2536 if (err)
2537 goto out_unregister_pppol2tp_proto;
2538
2539 #ifdef CONFIG_PROC_FS
2540 pppol2tp_proc = create_proc_entry("pppol2tp", 0, init_net.proc_net);
2541 if (!pppol2tp_proc) {
2542 err = -ENOMEM;
2543 goto out_unregister_pppox_proto;
2544 }
2545 pppol2tp_proc->proc_fops = &pppol2tp_proc_fops;
2546 #endif /* CONFIG_PROC_FS */
2547 printk(KERN_INFO "PPPoL2TP kernel driver, %s\n",
2548 PPPOL2TP_DRV_VERSION);
2549
2550 out:
2551 return err;
2552 #ifdef CONFIG_PROC_FS
2553 out_unregister_pppox_proto:
2554 unregister_pppox_proto(PX_PROTO_OL2TP);
2555 #endif
2556 out_unregister_pppol2tp_proto:
2557 proto_unregister(&pppol2tp_sk_proto);
2558 goto out;
2559 }
2560
2561 static void __exit pppol2tp_exit(void)
2562 {
2563 unregister_pppox_proto(PX_PROTO_OL2TP);
2564
2565 #ifdef CONFIG_PROC_FS
2566 remove_proc_entry("pppol2tp", init_net.proc_net);
2567 #endif
2568 proto_unregister(&pppol2tp_sk_proto);
2569 }
2570
2571 module_init(pppol2tp_init);
2572 module_exit(pppol2tp_exit);
2573
2574 MODULE_AUTHOR("Martijn van Oosterhout <kleptog@svana.org>, "
2575 "James Chapman <jchapman@katalix.com>");
2576 MODULE_DESCRIPTION("PPP over L2TP over UDP");
2577 MODULE_LICENSE("GPL");
2578 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
2579
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