1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*****************************************************************************
3 * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
4 *
5 * PPPoX --- Generic PPP encapsulation socket family
6 * PPPoL2TP --- PPP over L2TP (RFC 2661)
7 *
8 * Version: 2.0.0
9 *
10 * Authors: James Chapman (jchapman@katalix.com)
11 *
12 * Based on original work by Martijn van Oosterhout <kleptog@svana.org>
13 *
14 * License:
15 */
16
17 /* This driver handles only L2TP data frames; control frames are handled by a
18 * userspace application.
19 *
20 * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
21 * attaches it to a bound UDP socket with local tunnel_id / session_id and
22 * peer tunnel_id / session_id set. Data can then be sent or received using
23 * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
24 * can be read or modified using ioctl() or [gs]etsockopt() calls.
25 *
26 * When a PPPoL2TP socket is connected with local and peer session_id values
27 * zero, the socket is treated as a special tunnel management socket.
28 *
29 * Here's example userspace code to create a socket for sending/receiving data
30 * over an L2TP session:-
31 *
32 * struct sockaddr_pppol2tp sax;
33 * int fd;
34 * int session_fd;
35 *
36 * fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
37 *
38 * sax.sa_family = AF_PPPOX;
39 * sax.sa_protocol = PX_PROTO_OL2TP;
40 * sax.pppol2tp.fd = tunnel_fd; // bound UDP socket
41 * sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
42 * sax.pppol2tp.addr.sin_port = addr->sin_port;
43 * sax.pppol2tp.addr.sin_family = AF_INET;
44 * sax.pppol2tp.s_tunnel = tunnel_id;
45 * sax.pppol2tp.s_session = session_id;
46 * sax.pppol2tp.d_tunnel = peer_tunnel_id;
47 * sax.pppol2tp.d_session = peer_session_id;
48 *
49 * session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
50 *
51 * A pppd plugin that allows PPP traffic to be carried over L2TP using
52 * this driver is available from the OpenL2TP project at
53 * http://openl2tp.sourceforge.net.
54 */
55
56 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
57
58 #include <linux/module.h>
59 #include <linux/string.h>
60 #include <linux/list.h>
61 #include <linux/uaccess.h>
62
63 #include <linux/kernel.h>
64 #include <linux/spinlock.h>
65 #include <linux/kthread.h>
66 #include <linux/sched.h>
67 #include <linux/slab.h>
68 #include <linux/errno.h>
69 #include <linux/jiffies.h>
70
71 #include <linux/netdevice.h>
72 #include <linux/net.h>
73 #include <linux/inetdevice.h>
74 #include <linux/skbuff.h>
75 #include <linux/init.h>
76 #include <linux/ip.h>
77 #include <linux/udp.h>
78 #include <linux/if_pppox.h>
79 #include <linux/if_pppol2tp.h>
80 #include <net/sock.h>
81 #include <linux/ppp_channel.h>
82 #include <linux/ppp_defs.h>
83 #include <linux/ppp-ioctl.h>
84 #include <linux/file.h>
85 #include <linux/hash.h>
86 #include <linux/sort.h>
87 #include <linux/proc_fs.h>
88 #include <linux/l2tp.h>
89 #include <linux/nsproxy.h>
90 #include <net/net_namespace.h>
91 #include <net/netns/generic.h>
92 #include <net/ip.h>
93 #include <net/udp.h>
94 #include <net/inet_common.h>
95
96 #include <asm/byteorder.h>
97 #include <linux/atomic.h>
98
99 #include "l2tp_core.h"
100
101 #define PPPOL2TP_DRV_VERSION "V2.0"
102
103 /* Space for UDP, L2TP and PPP headers */
104 #define PPPOL2TP_HEADER_OVERHEAD 40
105
106 /* Number of bytes to build transmit L2TP headers.
107 * Unfortunately the size is different depending on whether sequence numbers
108 * are enabled.
109 */
110 #define PPPOL2TP_L2TP_HDR_SIZE_SEQ 10
111 #define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ 6
112
113 /* Private data of each session. This data lives at the end of struct
114 * l2tp_session, referenced via session->priv[].
115 */
116 struct pppol2tp_session {
117 int owner; /* pid that opened the socket */
118
119 struct mutex sk_lock; /* Protects .sk */
120 struct sock __rcu *sk; /* Pointer to the session PPPoX socket */
121 struct sock *__sk; /* Copy of .sk, for cleanup */
122 struct rcu_head rcu; /* For asynchronous release */
123 };
124
125 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
126
127 static const struct ppp_channel_ops pppol2tp_chan_ops = {
128 .start_xmit = pppol2tp_xmit,
129 };
130
131 static const struct proto_ops pppol2tp_ops;
132
133 /* Retrieves the pppol2tp socket associated to a session.
134 * A reference is held on the returned socket, so this function must be paired
135 * with sock_put().
136 */
pppol2tp_session_get_sock(struct l2tp_session * session)137 static struct sock *pppol2tp_session_get_sock(struct l2tp_session *session)
138 {
139 struct pppol2tp_session *ps = l2tp_session_priv(session);
140 struct sock *sk;
141
142 rcu_read_lock();
143 sk = rcu_dereference(ps->sk);
144 if (sk)
145 sock_hold(sk);
146 rcu_read_unlock();
147
148 return sk;
149 }
150
151 /* Helpers to obtain tunnel/session contexts from sockets.
152 */
pppol2tp_sock_to_session(struct sock * sk)153 static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
154 {
155 struct l2tp_session *session;
156
157 if (!sk)
158 return NULL;
159
160 sock_hold(sk);
161 session = (struct l2tp_session *)(sk->sk_user_data);
162 if (!session) {
163 sock_put(sk);
164 goto out;
165 }
166 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC)) {
167 session = NULL;
168 sock_put(sk);
169 goto out;
170 }
171
172 out:
173 return session;
174 }
175
176 /*****************************************************************************
177 * Receive data handling
178 *****************************************************************************/
179
180 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
181 */
pppol2tp_recvmsg(struct socket * sock,struct msghdr * msg,size_t len,int flags)182 static int pppol2tp_recvmsg(struct socket *sock, struct msghdr *msg,
183 size_t len, int flags)
184 {
185 int err;
186 struct sk_buff *skb;
187 struct sock *sk = sock->sk;
188
189 err = -EIO;
190 if (sk->sk_state & PPPOX_BOUND)
191 goto end;
192
193 err = 0;
194 skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
195 flags & MSG_DONTWAIT, &err);
196 if (!skb)
197 goto end;
198
199 if (len > skb->len)
200 len = skb->len;
201 else if (len < skb->len)
202 msg->msg_flags |= MSG_TRUNC;
203
204 err = skb_copy_datagram_msg(skb, 0, msg, len);
205 if (likely(err == 0))
206 err = len;
207
208 kfree_skb(skb);
209 end:
210 return err;
211 }
212
pppol2tp_recv(struct l2tp_session * session,struct sk_buff * skb,int data_len)213 static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
214 {
215 struct pppol2tp_session *ps = l2tp_session_priv(session);
216 struct sock *sk = NULL;
217
218 /* If the socket is bound, send it in to PPP's input queue. Otherwise
219 * queue it on the session socket.
220 */
221 rcu_read_lock();
222 sk = rcu_dereference(ps->sk);
223 if (!sk)
224 goto no_sock;
225
226 /* If the first two bytes are 0xFF03, consider that it is the PPP's
227 * Address and Control fields and skip them. The L2TP module has always
228 * worked this way, although, in theory, the use of these fields should
229 * be negociated and handled at the PPP layer. These fields are
230 * constant: 0xFF is the All-Stations Address and 0x03 the Unnumbered
231 * Information command with Poll/Final bit set to zero (RFC 1662).
232 */
233 if (pskb_may_pull(skb, 2) && skb->data[0] == PPP_ALLSTATIONS &&
234 skb->data[1] == PPP_UI)
235 skb_pull(skb, 2);
236
237 if (sk->sk_state & PPPOX_BOUND) {
238 struct pppox_sock *po;
239
240 po = pppox_sk(sk);
241 ppp_input(&po->chan, skb);
242 } else {
243 if (sock_queue_rcv_skb(sk, skb) < 0) {
244 atomic_long_inc(&session->stats.rx_errors);
245 kfree_skb(skb);
246 }
247 }
248 rcu_read_unlock();
249
250 return;
251
252 no_sock:
253 rcu_read_unlock();
254 pr_warn_ratelimited("%s: no socket in recv\n", session->name);
255 kfree_skb(skb);
256 }
257
258 /************************************************************************
259 * Transmit handling
260 ***********************************************************************/
261
262 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket. We come here
263 * when a user application does a sendmsg() on the session socket. L2TP and
264 * PPP headers must be inserted into the user's data.
265 */
pppol2tp_sendmsg(struct socket * sock,struct msghdr * m,size_t total_len)266 static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
267 size_t total_len)
268 {
269 struct sock *sk = sock->sk;
270 struct sk_buff *skb;
271 int error;
272 struct l2tp_session *session;
273 struct l2tp_tunnel *tunnel;
274 int uhlen;
275
276 error = -ENOTCONN;
277 if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
278 goto error;
279
280 /* Get session and tunnel contexts */
281 error = -EBADF;
282 session = pppol2tp_sock_to_session(sk);
283 if (!session)
284 goto error;
285
286 tunnel = session->tunnel;
287
288 uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
289
290 /* Allocate a socket buffer */
291 error = -ENOMEM;
292 skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
293 uhlen + session->hdr_len +
294 2 + total_len, /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
295 0, GFP_KERNEL);
296 if (!skb)
297 goto error_put_sess;
298
299 /* Reserve space for headers. */
300 skb_reserve(skb, NET_SKB_PAD);
301 skb_reset_network_header(skb);
302 skb_reserve(skb, sizeof(struct iphdr));
303 skb_reset_transport_header(skb);
304 skb_reserve(skb, uhlen);
305
306 /* Add PPP header */
307 skb->data[0] = PPP_ALLSTATIONS;
308 skb->data[1] = PPP_UI;
309 skb_put(skb, 2);
310
311 /* Copy user data into skb */
312 error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
313 if (error < 0) {
314 kfree_skb(skb);
315 goto error_put_sess;
316 }
317
318 local_bh_disable();
319 l2tp_xmit_skb(session, skb);
320 local_bh_enable();
321
322 sock_put(sk);
323
324 return total_len;
325
326 error_put_sess:
327 sock_put(sk);
328 error:
329 return error;
330 }
331
332 /* Transmit function called by generic PPP driver. Sends PPP frame
333 * over PPPoL2TP socket.
334 *
335 * This is almost the same as pppol2tp_sendmsg(), but rather than
336 * being called with a msghdr from userspace, it is called with a skb
337 * from the kernel.
338 *
339 * The supplied skb from ppp doesn't have enough headroom for the
340 * insertion of L2TP, UDP and IP headers so we need to allocate more
341 * headroom in the skb. This will create a cloned skb. But we must be
342 * careful in the error case because the caller will expect to free
343 * the skb it supplied, not our cloned skb. So we take care to always
344 * leave the original skb unfreed if we return an error.
345 */
pppol2tp_xmit(struct ppp_channel * chan,struct sk_buff * skb)346 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
347 {
348 struct sock *sk = (struct sock *)chan->private;
349 struct l2tp_session *session;
350 struct l2tp_tunnel *tunnel;
351 int uhlen, headroom;
352
353 if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
354 goto abort;
355
356 /* Get session and tunnel contexts from the socket */
357 session = pppol2tp_sock_to_session(sk);
358 if (!session)
359 goto abort;
360
361 tunnel = session->tunnel;
362
363 uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
364 headroom = NET_SKB_PAD +
365 sizeof(struct iphdr) + /* IP header */
366 uhlen + /* UDP header (if L2TP_ENCAPTYPE_UDP) */
367 session->hdr_len + /* L2TP header */
368 2; /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
369 if (skb_cow_head(skb, headroom))
370 goto abort_put_sess;
371
372 /* Setup PPP header */
373 __skb_push(skb, 2);
374 skb->data[0] = PPP_ALLSTATIONS;
375 skb->data[1] = PPP_UI;
376
377 local_bh_disable();
378 l2tp_xmit_skb(session, skb);
379 local_bh_enable();
380
381 sock_put(sk);
382
383 return 1;
384
385 abort_put_sess:
386 sock_put(sk);
387 abort:
388 /* Free the original skb */
389 kfree_skb(skb);
390 return 1;
391 }
392
393 /*****************************************************************************
394 * Session (and tunnel control) socket create/destroy.
395 *****************************************************************************/
396
pppol2tp_put_sk(struct rcu_head * head)397 static void pppol2tp_put_sk(struct rcu_head *head)
398 {
399 struct pppol2tp_session *ps;
400
401 ps = container_of(head, typeof(*ps), rcu);
402 sock_put(ps->__sk);
403 }
404
405 /* Really kill the session socket. (Called from sock_put() if
406 * refcnt == 0.)
407 */
pppol2tp_session_destruct(struct sock * sk)408 static void pppol2tp_session_destruct(struct sock *sk)
409 {
410 struct l2tp_session *session = sk->sk_user_data;
411
412 skb_queue_purge(&sk->sk_receive_queue);
413 skb_queue_purge(&sk->sk_write_queue);
414
415 if (session) {
416 sk->sk_user_data = NULL;
417 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
418 return;
419 l2tp_session_dec_refcount(session);
420 }
421 }
422
423 /* Called when the PPPoX socket (session) is closed.
424 */
pppol2tp_release(struct socket * sock)425 static int pppol2tp_release(struct socket *sock)
426 {
427 struct sock *sk = sock->sk;
428 struct l2tp_session *session;
429 int error;
430
431 if (!sk)
432 return 0;
433
434 error = -EBADF;
435 lock_sock(sk);
436 if (sock_flag(sk, SOCK_DEAD) != 0)
437 goto error;
438
439 pppox_unbind_sock(sk);
440
441 /* Signal the death of the socket. */
442 sk->sk_state = PPPOX_DEAD;
443 sock_orphan(sk);
444 sock->sk = NULL;
445
446 session = pppol2tp_sock_to_session(sk);
447 if (session) {
448 struct pppol2tp_session *ps;
449
450 l2tp_session_delete(session);
451
452 ps = l2tp_session_priv(session);
453 mutex_lock(&ps->sk_lock);
454 ps->__sk = rcu_dereference_protected(ps->sk,
455 lockdep_is_held(&ps->sk_lock));
456 RCU_INIT_POINTER(ps->sk, NULL);
457 mutex_unlock(&ps->sk_lock);
458 call_rcu(&ps->rcu, pppol2tp_put_sk);
459
460 /* Rely on the sock_put() call at the end of the function for
461 * dropping the reference held by pppol2tp_sock_to_session().
462 * The last reference will be dropped by pppol2tp_put_sk().
463 */
464 }
465
466 release_sock(sk);
467
468 /* This will delete the session context via
469 * pppol2tp_session_destruct() if the socket's refcnt drops to
470 * zero.
471 */
472 sock_put(sk);
473
474 return 0;
475
476 error:
477 release_sock(sk);
478 return error;
479 }
480
481 static struct proto pppol2tp_sk_proto = {
482 .name = "PPPOL2TP",
483 .owner = THIS_MODULE,
484 .obj_size = sizeof(struct pppox_sock),
485 };
486
pppol2tp_backlog_recv(struct sock * sk,struct sk_buff * skb)487 static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
488 {
489 int rc;
490
491 rc = l2tp_udp_encap_recv(sk, skb);
492 if (rc)
493 kfree_skb(skb);
494
495 return NET_RX_SUCCESS;
496 }
497
498 /* socket() handler. Initialize a new struct sock.
499 */
pppol2tp_create(struct net * net,struct socket * sock,int kern)500 static int pppol2tp_create(struct net *net, struct socket *sock, int kern)
501 {
502 int error = -ENOMEM;
503 struct sock *sk;
504
505 sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto, kern);
506 if (!sk)
507 goto out;
508
509 sock_init_data(sock, sk);
510
511 sock->state = SS_UNCONNECTED;
512 sock->ops = &pppol2tp_ops;
513
514 sk->sk_backlog_rcv = pppol2tp_backlog_recv;
515 sk->sk_protocol = PX_PROTO_OL2TP;
516 sk->sk_family = PF_PPPOX;
517 sk->sk_state = PPPOX_NONE;
518 sk->sk_type = SOCK_STREAM;
519 sk->sk_destruct = pppol2tp_session_destruct;
520
521 error = 0;
522
523 out:
524 return error;
525 }
526
pppol2tp_show(struct seq_file * m,void * arg)527 static void pppol2tp_show(struct seq_file *m, void *arg)
528 {
529 struct l2tp_session *session = arg;
530 struct sock *sk;
531
532 sk = pppol2tp_session_get_sock(session);
533 if (sk) {
534 struct pppox_sock *po = pppox_sk(sk);
535
536 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
537 sock_put(sk);
538 }
539 }
540
pppol2tp_session_init(struct l2tp_session * session)541 static void pppol2tp_session_init(struct l2tp_session *session)
542 {
543 struct pppol2tp_session *ps;
544
545 session->recv_skb = pppol2tp_recv;
546 if (IS_ENABLED(CONFIG_L2TP_DEBUGFS))
547 session->show = pppol2tp_show;
548
549 ps = l2tp_session_priv(session);
550 mutex_init(&ps->sk_lock);
551 ps->owner = current->pid;
552 }
553
554 struct l2tp_connect_info {
555 u8 version;
556 int fd;
557 u32 tunnel_id;
558 u32 peer_tunnel_id;
559 u32 session_id;
560 u32 peer_session_id;
561 };
562
pppol2tp_sockaddr_get_info(const void * sa,int sa_len,struct l2tp_connect_info * info)563 static int pppol2tp_sockaddr_get_info(const void *sa, int sa_len,
564 struct l2tp_connect_info *info)
565 {
566 switch (sa_len) {
567 case sizeof(struct sockaddr_pppol2tp):
568 {
569 const struct sockaddr_pppol2tp *sa_v2in4 = sa;
570
571 if (sa_v2in4->sa_protocol != PX_PROTO_OL2TP)
572 return -EINVAL;
573
574 info->version = 2;
575 info->fd = sa_v2in4->pppol2tp.fd;
576 info->tunnel_id = sa_v2in4->pppol2tp.s_tunnel;
577 info->peer_tunnel_id = sa_v2in4->pppol2tp.d_tunnel;
578 info->session_id = sa_v2in4->pppol2tp.s_session;
579 info->peer_session_id = sa_v2in4->pppol2tp.d_session;
580
581 break;
582 }
583 case sizeof(struct sockaddr_pppol2tpv3):
584 {
585 const struct sockaddr_pppol2tpv3 *sa_v3in4 = sa;
586
587 if (sa_v3in4->sa_protocol != PX_PROTO_OL2TP)
588 return -EINVAL;
589
590 info->version = 3;
591 info->fd = sa_v3in4->pppol2tp.fd;
592 info->tunnel_id = sa_v3in4->pppol2tp.s_tunnel;
593 info->peer_tunnel_id = sa_v3in4->pppol2tp.d_tunnel;
594 info->session_id = sa_v3in4->pppol2tp.s_session;
595 info->peer_session_id = sa_v3in4->pppol2tp.d_session;
596
597 break;
598 }
599 case sizeof(struct sockaddr_pppol2tpin6):
600 {
601 const struct sockaddr_pppol2tpin6 *sa_v2in6 = sa;
602
603 if (sa_v2in6->sa_protocol != PX_PROTO_OL2TP)
604 return -EINVAL;
605
606 info->version = 2;
607 info->fd = sa_v2in6->pppol2tp.fd;
608 info->tunnel_id = sa_v2in6->pppol2tp.s_tunnel;
609 info->peer_tunnel_id = sa_v2in6->pppol2tp.d_tunnel;
610 info->session_id = sa_v2in6->pppol2tp.s_session;
611 info->peer_session_id = sa_v2in6->pppol2tp.d_session;
612
613 break;
614 }
615 case sizeof(struct sockaddr_pppol2tpv3in6):
616 {
617 const struct sockaddr_pppol2tpv3in6 *sa_v3in6 = sa;
618
619 if (sa_v3in6->sa_protocol != PX_PROTO_OL2TP)
620 return -EINVAL;
621
622 info->version = 3;
623 info->fd = sa_v3in6->pppol2tp.fd;
624 info->tunnel_id = sa_v3in6->pppol2tp.s_tunnel;
625 info->peer_tunnel_id = sa_v3in6->pppol2tp.d_tunnel;
626 info->session_id = sa_v3in6->pppol2tp.s_session;
627 info->peer_session_id = sa_v3in6->pppol2tp.d_session;
628
629 break;
630 }
631 default:
632 return -EINVAL;
633 }
634
635 return 0;
636 }
637
638 /* Rough estimation of the maximum payload size a tunnel can transmit without
639 * fragmenting at the lower IP layer. Assumes L2TPv2 with sequence
640 * numbers and no IP option. Not quite accurate, but the result is mostly
641 * unused anyway.
642 */
pppol2tp_tunnel_mtu(const struct l2tp_tunnel * tunnel)643 static int pppol2tp_tunnel_mtu(const struct l2tp_tunnel *tunnel)
644 {
645 int mtu;
646
647 mtu = l2tp_tunnel_dst_mtu(tunnel);
648 if (mtu <= PPPOL2TP_HEADER_OVERHEAD)
649 return 1500 - PPPOL2TP_HEADER_OVERHEAD;
650
651 return mtu - PPPOL2TP_HEADER_OVERHEAD;
652 }
653
pppol2tp_tunnel_get(struct net * net,const struct l2tp_connect_info * info,bool * new_tunnel)654 static struct l2tp_tunnel *pppol2tp_tunnel_get(struct net *net,
655 const struct l2tp_connect_info *info,
656 bool *new_tunnel)
657 {
658 struct l2tp_tunnel *tunnel;
659 int error;
660
661 *new_tunnel = false;
662
663 tunnel = l2tp_tunnel_get(net, info->tunnel_id);
664
665 /* Special case: create tunnel context if session_id and
666 * peer_session_id is 0. Otherwise look up tunnel using supplied
667 * tunnel id.
668 */
669 if (!info->session_id && !info->peer_session_id) {
670 if (!tunnel) {
671 struct l2tp_tunnel_cfg tcfg = {
672 .encap = L2TP_ENCAPTYPE_UDP,
673 };
674
675 /* Prevent l2tp_tunnel_register() from trying to set up
676 * a kernel socket.
677 */
678 if (info->fd < 0)
679 return ERR_PTR(-EBADF);
680
681 error = l2tp_tunnel_create(info->fd,
682 info->version,
683 info->tunnel_id,
684 info->peer_tunnel_id, &tcfg,
685 &tunnel);
686 if (error < 0)
687 return ERR_PTR(error);
688
689 l2tp_tunnel_inc_refcount(tunnel);
690 error = l2tp_tunnel_register(tunnel, net, &tcfg);
691 if (error < 0) {
692 kfree(tunnel);
693 return ERR_PTR(error);
694 }
695
696 *new_tunnel = true;
697 }
698 } else {
699 /* Error if we can't find the tunnel */
700 if (!tunnel)
701 return ERR_PTR(-ENOENT);
702
703 /* Error if socket is not prepped */
704 if (!tunnel->sock) {
705 l2tp_tunnel_dec_refcount(tunnel);
706 return ERR_PTR(-ENOENT);
707 }
708 }
709
710 return tunnel;
711 }
712
713 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
714 */
pppol2tp_connect(struct socket * sock,struct sockaddr * uservaddr,int sockaddr_len,int flags)715 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
716 int sockaddr_len, int flags)
717 {
718 struct sock *sk = sock->sk;
719 struct pppox_sock *po = pppox_sk(sk);
720 struct l2tp_session *session = NULL;
721 struct l2tp_connect_info info;
722 struct l2tp_tunnel *tunnel;
723 struct pppol2tp_session *ps;
724 struct l2tp_session_cfg cfg = { 0, };
725 bool drop_refcnt = false;
726 bool new_session = false;
727 bool new_tunnel = false;
728 int error;
729
730 error = pppol2tp_sockaddr_get_info(uservaddr, sockaddr_len, &info);
731 if (error < 0)
732 return error;
733
734 /* Don't bind if tunnel_id is 0 */
735 if (!info.tunnel_id)
736 return -EINVAL;
737
738 tunnel = pppol2tp_tunnel_get(sock_net(sk), &info, &new_tunnel);
739 if (IS_ERR(tunnel))
740 return PTR_ERR(tunnel);
741
742 lock_sock(sk);
743
744 /* Check for already bound sockets */
745 error = -EBUSY;
746 if (sk->sk_state & PPPOX_CONNECTED)
747 goto end;
748
749 /* We don't supporting rebinding anyway */
750 error = -EALREADY;
751 if (sk->sk_user_data)
752 goto end; /* socket is already attached */
753
754 if (tunnel->peer_tunnel_id == 0)
755 tunnel->peer_tunnel_id = info.peer_tunnel_id;
756
757 session = l2tp_tunnel_get_session(tunnel, info.session_id);
758 if (session) {
759 drop_refcnt = true;
760
761 if (session->pwtype != L2TP_PWTYPE_PPP) {
762 error = -EPROTOTYPE;
763 goto end;
764 }
765
766 ps = l2tp_session_priv(session);
767
768 /* Using a pre-existing session is fine as long as it hasn't
769 * been connected yet.
770 */
771 mutex_lock(&ps->sk_lock);
772 if (rcu_dereference_protected(ps->sk,
773 lockdep_is_held(&ps->sk_lock)) ||
774 ps->__sk) {
775 mutex_unlock(&ps->sk_lock);
776 error = -EEXIST;
777 goto end;
778 }
779 } else {
780 cfg.pw_type = L2TP_PWTYPE_PPP;
781
782 session = l2tp_session_create(sizeof(struct pppol2tp_session),
783 tunnel, info.session_id,
784 info.peer_session_id, &cfg);
785 if (IS_ERR(session)) {
786 error = PTR_ERR(session);
787 goto end;
788 }
789
790 pppol2tp_session_init(session);
791 ps = l2tp_session_priv(session);
792 l2tp_session_inc_refcount(session);
793
794 mutex_lock(&ps->sk_lock);
795 error = l2tp_session_register(session, tunnel);
796 if (error < 0) {
797 mutex_unlock(&ps->sk_lock);
798 kfree(session);
799 goto end;
800 }
801 drop_refcnt = true;
802 new_session = true;
803 }
804
805 /* Special case: if source & dest session_id == 0x0000, this
806 * socket is being created to manage the tunnel. Just set up
807 * the internal context for use by ioctl() and sockopt()
808 * handlers.
809 */
810 if (session->session_id == 0 && session->peer_session_id == 0) {
811 error = 0;
812 goto out_no_ppp;
813 }
814
815 /* The only header we need to worry about is the L2TP
816 * header. This size is different depending on whether
817 * sequence numbers are enabled for the data channel.
818 */
819 po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
820
821 po->chan.private = sk;
822 po->chan.ops = &pppol2tp_chan_ops;
823 po->chan.mtu = pppol2tp_tunnel_mtu(tunnel);
824
825 error = ppp_register_net_channel(sock_net(sk), &po->chan);
826 if (error) {
827 mutex_unlock(&ps->sk_lock);
828 goto end;
829 }
830
831 out_no_ppp:
832 /* This is how we get the session context from the socket. */
833 sk->sk_user_data = session;
834 rcu_assign_pointer(ps->sk, sk);
835 mutex_unlock(&ps->sk_lock);
836
837 /* Keep the reference we've grabbed on the session: sk doesn't expect
838 * the session to disappear. pppol2tp_session_destruct() is responsible
839 * for dropping it.
840 */
841 drop_refcnt = false;
842
843 sk->sk_state = PPPOX_CONNECTED;
844
845 end:
846 if (error) {
847 if (new_session)
848 l2tp_session_delete(session);
849 if (new_tunnel)
850 l2tp_tunnel_delete(tunnel);
851 }
852 if (drop_refcnt)
853 l2tp_session_dec_refcount(session);
854 l2tp_tunnel_dec_refcount(tunnel);
855 release_sock(sk);
856
857 return error;
858 }
859
860 #ifdef CONFIG_L2TP_V3
861
862 /* Called when creating sessions via the netlink interface. */
pppol2tp_session_create(struct net * net,struct l2tp_tunnel * tunnel,u32 session_id,u32 peer_session_id,struct l2tp_session_cfg * cfg)863 static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
864 u32 session_id, u32 peer_session_id,
865 struct l2tp_session_cfg *cfg)
866 {
867 int error;
868 struct l2tp_session *session;
869
870 /* Error if tunnel socket is not prepped */
871 if (!tunnel->sock) {
872 error = -ENOENT;
873 goto err;
874 }
875
876 /* Allocate and initialize a new session context. */
877 session = l2tp_session_create(sizeof(struct pppol2tp_session),
878 tunnel, session_id,
879 peer_session_id, cfg);
880 if (IS_ERR(session)) {
881 error = PTR_ERR(session);
882 goto err;
883 }
884
885 pppol2tp_session_init(session);
886
887 error = l2tp_session_register(session, tunnel);
888 if (error < 0)
889 goto err_sess;
890
891 return 0;
892
893 err_sess:
894 kfree(session);
895 err:
896 return error;
897 }
898
899 #endif /* CONFIG_L2TP_V3 */
900
901 /* getname() support.
902 */
pppol2tp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)903 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
904 int peer)
905 {
906 int len = 0;
907 int error = 0;
908 struct l2tp_session *session;
909 struct l2tp_tunnel *tunnel;
910 struct sock *sk = sock->sk;
911 struct inet_sock *inet;
912 struct pppol2tp_session *pls;
913
914 error = -ENOTCONN;
915 if (!sk)
916 goto end;
917 if (!(sk->sk_state & PPPOX_CONNECTED))
918 goto end;
919
920 error = -EBADF;
921 session = pppol2tp_sock_to_session(sk);
922 if (!session)
923 goto end;
924
925 pls = l2tp_session_priv(session);
926 tunnel = session->tunnel;
927
928 inet = inet_sk(tunnel->sock);
929 if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET) {
930 struct sockaddr_pppol2tp sp;
931
932 len = sizeof(sp);
933 memset(&sp, 0, len);
934 sp.sa_family = AF_PPPOX;
935 sp.sa_protocol = PX_PROTO_OL2TP;
936 sp.pppol2tp.fd = tunnel->fd;
937 sp.pppol2tp.pid = pls->owner;
938 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
939 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
940 sp.pppol2tp.s_session = session->session_id;
941 sp.pppol2tp.d_session = session->peer_session_id;
942 sp.pppol2tp.addr.sin_family = AF_INET;
943 sp.pppol2tp.addr.sin_port = inet->inet_dport;
944 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
945 memcpy(uaddr, &sp, len);
946 #if IS_ENABLED(CONFIG_IPV6)
947 } else if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET6) {
948 struct sockaddr_pppol2tpin6 sp;
949
950 len = sizeof(sp);
951 memset(&sp, 0, len);
952 sp.sa_family = AF_PPPOX;
953 sp.sa_protocol = PX_PROTO_OL2TP;
954 sp.pppol2tp.fd = tunnel->fd;
955 sp.pppol2tp.pid = pls->owner;
956 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
957 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
958 sp.pppol2tp.s_session = session->session_id;
959 sp.pppol2tp.d_session = session->peer_session_id;
960 sp.pppol2tp.addr.sin6_family = AF_INET6;
961 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
962 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
963 sizeof(tunnel->sock->sk_v6_daddr));
964 memcpy(uaddr, &sp, len);
965 } else if (tunnel->version == 3 && tunnel->sock->sk_family == AF_INET6) {
966 struct sockaddr_pppol2tpv3in6 sp;
967
968 len = sizeof(sp);
969 memset(&sp, 0, len);
970 sp.sa_family = AF_PPPOX;
971 sp.sa_protocol = PX_PROTO_OL2TP;
972 sp.pppol2tp.fd = tunnel->fd;
973 sp.pppol2tp.pid = pls->owner;
974 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
975 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
976 sp.pppol2tp.s_session = session->session_id;
977 sp.pppol2tp.d_session = session->peer_session_id;
978 sp.pppol2tp.addr.sin6_family = AF_INET6;
979 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
980 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
981 sizeof(tunnel->sock->sk_v6_daddr));
982 memcpy(uaddr, &sp, len);
983 #endif
984 } else if (tunnel->version == 3) {
985 struct sockaddr_pppol2tpv3 sp;
986
987 len = sizeof(sp);
988 memset(&sp, 0, len);
989 sp.sa_family = AF_PPPOX;
990 sp.sa_protocol = PX_PROTO_OL2TP;
991 sp.pppol2tp.fd = tunnel->fd;
992 sp.pppol2tp.pid = pls->owner;
993 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
994 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
995 sp.pppol2tp.s_session = session->session_id;
996 sp.pppol2tp.d_session = session->peer_session_id;
997 sp.pppol2tp.addr.sin_family = AF_INET;
998 sp.pppol2tp.addr.sin_port = inet->inet_dport;
999 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
1000 memcpy(uaddr, &sp, len);
1001 }
1002
1003 error = len;
1004
1005 sock_put(sk);
1006 end:
1007 return error;
1008 }
1009
1010 /****************************************************************************
1011 * ioctl() handlers.
1012 *
1013 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1014 * sockets. However, in order to control kernel tunnel features, we allow
1015 * userspace to create a special "tunnel" PPPoX socket which is used for
1016 * control only. Tunnel PPPoX sockets have session_id == 0 and simply allow
1017 * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1018 * calls.
1019 ****************************************************************************/
1020
pppol2tp_copy_stats(struct pppol2tp_ioc_stats * dest,const struct l2tp_stats * stats)1021 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
1022 const struct l2tp_stats *stats)
1023 {
1024 memset(dest, 0, sizeof(*dest));
1025
1026 dest->tx_packets = atomic_long_read(&stats->tx_packets);
1027 dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
1028 dest->tx_errors = atomic_long_read(&stats->tx_errors);
1029 dest->rx_packets = atomic_long_read(&stats->rx_packets);
1030 dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
1031 dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
1032 dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
1033 dest->rx_errors = atomic_long_read(&stats->rx_errors);
1034 }
1035
pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats * stats,struct l2tp_tunnel * tunnel)1036 static int pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats *stats,
1037 struct l2tp_tunnel *tunnel)
1038 {
1039 struct l2tp_session *session;
1040
1041 if (!stats->session_id) {
1042 pppol2tp_copy_stats(stats, &tunnel->stats);
1043 return 0;
1044 }
1045
1046 /* If session_id is set, search the corresponding session in the
1047 * context of this tunnel and record the session's statistics.
1048 */
1049 session = l2tp_tunnel_get_session(tunnel, stats->session_id);
1050 if (!session)
1051 return -EBADR;
1052
1053 if (session->pwtype != L2TP_PWTYPE_PPP) {
1054 l2tp_session_dec_refcount(session);
1055 return -EBADR;
1056 }
1057
1058 pppol2tp_copy_stats(stats, &session->stats);
1059 l2tp_session_dec_refcount(session);
1060
1061 return 0;
1062 }
1063
pppol2tp_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)1064 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1065 unsigned long arg)
1066 {
1067 struct pppol2tp_ioc_stats stats;
1068 struct l2tp_session *session;
1069
1070 switch (cmd) {
1071 case PPPIOCGMRU:
1072 case PPPIOCGFLAGS:
1073 session = sock->sk->sk_user_data;
1074 if (!session)
1075 return -ENOTCONN;
1076
1077 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1078 return -EBADF;
1079
1080 /* Not defined for tunnels */
1081 if (!session->session_id && !session->peer_session_id)
1082 return -ENOSYS;
1083
1084 if (put_user(0, (int __user *)arg))
1085 return -EFAULT;
1086 break;
1087
1088 case PPPIOCSMRU:
1089 case PPPIOCSFLAGS:
1090 session = sock->sk->sk_user_data;
1091 if (!session)
1092 return -ENOTCONN;
1093
1094 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1095 return -EBADF;
1096
1097 /* Not defined for tunnels */
1098 if (!session->session_id && !session->peer_session_id)
1099 return -ENOSYS;
1100
1101 if (!access_ok((int __user *)arg, sizeof(int)))
1102 return -EFAULT;
1103 break;
1104
1105 case PPPIOCGL2TPSTATS:
1106 session = sock->sk->sk_user_data;
1107 if (!session)
1108 return -ENOTCONN;
1109
1110 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1111 return -EBADF;
1112
1113 /* Session 0 represents the parent tunnel */
1114 if (!session->session_id && !session->peer_session_id) {
1115 u32 session_id;
1116 int err;
1117
1118 if (copy_from_user(&stats, (void __user *)arg,
1119 sizeof(stats)))
1120 return -EFAULT;
1121
1122 session_id = stats.session_id;
1123 err = pppol2tp_tunnel_copy_stats(&stats,
1124 session->tunnel);
1125 if (err < 0)
1126 return err;
1127
1128 stats.session_id = session_id;
1129 } else {
1130 pppol2tp_copy_stats(&stats, &session->stats);
1131 stats.session_id = session->session_id;
1132 }
1133 stats.tunnel_id = session->tunnel->tunnel_id;
1134 stats.using_ipsec = l2tp_tunnel_uses_xfrm(session->tunnel);
1135
1136 if (copy_to_user((void __user *)arg, &stats, sizeof(stats)))
1137 return -EFAULT;
1138 break;
1139
1140 default:
1141 return -ENOIOCTLCMD;
1142 }
1143
1144 return 0;
1145 }
1146
1147 /*****************************************************************************
1148 * setsockopt() / getsockopt() support.
1149 *
1150 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1151 * sockets. In order to control kernel tunnel features, we allow userspace to
1152 * create a special "tunnel" PPPoX socket which is used for control only.
1153 * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1154 * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1155 *****************************************************************************/
1156
1157 /* Tunnel setsockopt() helper.
1158 */
pppol2tp_tunnel_setsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int val)1159 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1160 struct l2tp_tunnel *tunnel,
1161 int optname, int val)
1162 {
1163 int err = 0;
1164
1165 switch (optname) {
1166 case PPPOL2TP_SO_DEBUG:
1167 /* Tunnel debug flags option is deprecated */
1168 break;
1169
1170 default:
1171 err = -ENOPROTOOPT;
1172 break;
1173 }
1174
1175 return err;
1176 }
1177
1178 /* Session setsockopt helper.
1179 */
pppol2tp_session_setsockopt(struct sock * sk,struct l2tp_session * session,int optname,int val)1180 static int pppol2tp_session_setsockopt(struct sock *sk,
1181 struct l2tp_session *session,
1182 int optname, int val)
1183 {
1184 int err = 0;
1185
1186 switch (optname) {
1187 case PPPOL2TP_SO_RECVSEQ:
1188 if (val != 0 && val != 1) {
1189 err = -EINVAL;
1190 break;
1191 }
1192 session->recv_seq = !!val;
1193 break;
1194
1195 case PPPOL2TP_SO_SENDSEQ:
1196 if (val != 0 && val != 1) {
1197 err = -EINVAL;
1198 break;
1199 }
1200 session->send_seq = !!val;
1201 {
1202 struct pppox_sock *po = pppox_sk(sk);
1203
1204 po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1205 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1206 }
1207 l2tp_session_set_header_len(session, session->tunnel->version);
1208 break;
1209
1210 case PPPOL2TP_SO_LNSMODE:
1211 if (val != 0 && val != 1) {
1212 err = -EINVAL;
1213 break;
1214 }
1215 session->lns_mode = !!val;
1216 break;
1217
1218 case PPPOL2TP_SO_DEBUG:
1219 /* Session debug flags option is deprecated */
1220 break;
1221
1222 case PPPOL2TP_SO_REORDERTO:
1223 session->reorder_timeout = msecs_to_jiffies(val);
1224 break;
1225
1226 default:
1227 err = -ENOPROTOOPT;
1228 break;
1229 }
1230
1231 return err;
1232 }
1233
1234 /* Main setsockopt() entry point.
1235 * Does API checks, then calls either the tunnel or session setsockopt
1236 * handler, according to whether the PPPoL2TP socket is a for a regular
1237 * session or the special tunnel type.
1238 */
pppol2tp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1239 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1240 sockptr_t optval, unsigned int optlen)
1241 {
1242 struct sock *sk = sock->sk;
1243 struct l2tp_session *session;
1244 struct l2tp_tunnel *tunnel;
1245 int val;
1246 int err;
1247
1248 if (level != SOL_PPPOL2TP)
1249 return -EINVAL;
1250
1251 if (optlen < sizeof(int))
1252 return -EINVAL;
1253
1254 if (copy_from_sockptr(&val, optval, sizeof(int)))
1255 return -EFAULT;
1256
1257 err = -ENOTCONN;
1258 if (!sk->sk_user_data)
1259 goto end;
1260
1261 /* Get session context from the socket */
1262 err = -EBADF;
1263 session = pppol2tp_sock_to_session(sk);
1264 if (!session)
1265 goto end;
1266
1267 /* Special case: if session_id == 0x0000, treat as operation on tunnel
1268 */
1269 if (session->session_id == 0 && session->peer_session_id == 0) {
1270 tunnel = session->tunnel;
1271 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1272 } else {
1273 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1274 }
1275
1276 sock_put(sk);
1277 end:
1278 return err;
1279 }
1280
1281 /* Tunnel getsockopt helper. Called with sock locked.
1282 */
pppol2tp_tunnel_getsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int * val)1283 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1284 struct l2tp_tunnel *tunnel,
1285 int optname, int *val)
1286 {
1287 int err = 0;
1288
1289 switch (optname) {
1290 case PPPOL2TP_SO_DEBUG:
1291 /* Tunnel debug flags option is deprecated */
1292 *val = 0;
1293 break;
1294
1295 default:
1296 err = -ENOPROTOOPT;
1297 break;
1298 }
1299
1300 return err;
1301 }
1302
1303 /* Session getsockopt helper. Called with sock locked.
1304 */
pppol2tp_session_getsockopt(struct sock * sk,struct l2tp_session * session,int optname,int * val)1305 static int pppol2tp_session_getsockopt(struct sock *sk,
1306 struct l2tp_session *session,
1307 int optname, int *val)
1308 {
1309 int err = 0;
1310
1311 switch (optname) {
1312 case PPPOL2TP_SO_RECVSEQ:
1313 *val = session->recv_seq;
1314 break;
1315
1316 case PPPOL2TP_SO_SENDSEQ:
1317 *val = session->send_seq;
1318 break;
1319
1320 case PPPOL2TP_SO_LNSMODE:
1321 *val = session->lns_mode;
1322 break;
1323
1324 case PPPOL2TP_SO_DEBUG:
1325 /* Session debug flags option is deprecated */
1326 *val = 0;
1327 break;
1328
1329 case PPPOL2TP_SO_REORDERTO:
1330 *val = (int)jiffies_to_msecs(session->reorder_timeout);
1331 break;
1332
1333 default:
1334 err = -ENOPROTOOPT;
1335 }
1336
1337 return err;
1338 }
1339
1340 /* Main getsockopt() entry point.
1341 * Does API checks, then calls either the tunnel or session getsockopt
1342 * handler, according to whether the PPPoX socket is a for a regular session
1343 * or the special tunnel type.
1344 */
pppol2tp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1345 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1346 char __user *optval, int __user *optlen)
1347 {
1348 struct sock *sk = sock->sk;
1349 struct l2tp_session *session;
1350 struct l2tp_tunnel *tunnel;
1351 int val, len;
1352 int err;
1353
1354 if (level != SOL_PPPOL2TP)
1355 return -EINVAL;
1356
1357 if (get_user(len, optlen))
1358 return -EFAULT;
1359
1360 len = min_t(unsigned int, len, sizeof(int));
1361
1362 if (len < 0)
1363 return -EINVAL;
1364
1365 err = -ENOTCONN;
1366 if (!sk->sk_user_data)
1367 goto end;
1368
1369 /* Get the session context */
1370 err = -EBADF;
1371 session = pppol2tp_sock_to_session(sk);
1372 if (!session)
1373 goto end;
1374
1375 /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1376 if (session->session_id == 0 && session->peer_session_id == 0) {
1377 tunnel = session->tunnel;
1378 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1379 if (err)
1380 goto end_put_sess;
1381 } else {
1382 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1383 if (err)
1384 goto end_put_sess;
1385 }
1386
1387 err = -EFAULT;
1388 if (put_user(len, optlen))
1389 goto end_put_sess;
1390
1391 if (copy_to_user((void __user *)optval, &val, len))
1392 goto end_put_sess;
1393
1394 err = 0;
1395
1396 end_put_sess:
1397 sock_put(sk);
1398 end:
1399 return err;
1400 }
1401
1402 /*****************************************************************************
1403 * /proc filesystem for debug
1404 * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1405 * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1406 *****************************************************************************/
1407
1408 static unsigned int pppol2tp_net_id;
1409
1410 #ifdef CONFIG_PROC_FS
1411
1412 struct pppol2tp_seq_data {
1413 struct seq_net_private p;
1414 int tunnel_idx; /* current tunnel */
1415 int session_idx; /* index of session within current tunnel */
1416 struct l2tp_tunnel *tunnel;
1417 struct l2tp_session *session; /* NULL means get next tunnel */
1418 };
1419
pppol2tp_next_tunnel(struct net * net,struct pppol2tp_seq_data * pd)1420 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1421 {
1422 /* Drop reference taken during previous invocation */
1423 if (pd->tunnel)
1424 l2tp_tunnel_dec_refcount(pd->tunnel);
1425
1426 for (;;) {
1427 pd->tunnel = l2tp_tunnel_get_nth(net, pd->tunnel_idx);
1428 pd->tunnel_idx++;
1429
1430 /* Only accept L2TPv2 tunnels */
1431 if (!pd->tunnel || pd->tunnel->version == 2)
1432 return;
1433
1434 l2tp_tunnel_dec_refcount(pd->tunnel);
1435 }
1436 }
1437
pppol2tp_next_session(struct net * net,struct pppol2tp_seq_data * pd)1438 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1439 {
1440 /* Drop reference taken during previous invocation */
1441 if (pd->session)
1442 l2tp_session_dec_refcount(pd->session);
1443
1444 pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
1445 pd->session_idx++;
1446
1447 if (!pd->session) {
1448 pd->session_idx = 0;
1449 pppol2tp_next_tunnel(net, pd);
1450 }
1451 }
1452
pppol2tp_seq_start(struct seq_file * m,loff_t * offs)1453 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1454 {
1455 struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1456 loff_t pos = *offs;
1457 struct net *net;
1458
1459 if (!pos)
1460 goto out;
1461
1462 if (WARN_ON(!m->private)) {
1463 pd = NULL;
1464 goto out;
1465 }
1466
1467 pd = m->private;
1468 net = seq_file_net(m);
1469
1470 if (!pd->tunnel)
1471 pppol2tp_next_tunnel(net, pd);
1472 else
1473 pppol2tp_next_session(net, pd);
1474
1475 /* NULL tunnel and session indicates end of list */
1476 if (!pd->tunnel && !pd->session)
1477 pd = NULL;
1478
1479 out:
1480 return pd;
1481 }
1482
pppol2tp_seq_next(struct seq_file * m,void * v,loff_t * pos)1483 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1484 {
1485 (*pos)++;
1486 return NULL;
1487 }
1488
pppol2tp_seq_stop(struct seq_file * p,void * v)1489 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1490 {
1491 struct pppol2tp_seq_data *pd = v;
1492
1493 if (!pd || pd == SEQ_START_TOKEN)
1494 return;
1495
1496 /* Drop reference taken by last invocation of pppol2tp_next_session()
1497 * or pppol2tp_next_tunnel().
1498 */
1499 if (pd->session) {
1500 l2tp_session_dec_refcount(pd->session);
1501 pd->session = NULL;
1502 }
1503 if (pd->tunnel) {
1504 l2tp_tunnel_dec_refcount(pd->tunnel);
1505 pd->tunnel = NULL;
1506 }
1507 }
1508
pppol2tp_seq_tunnel_show(struct seq_file * m,void * v)1509 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1510 {
1511 struct l2tp_tunnel *tunnel = v;
1512
1513 seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1514 tunnel->name,
1515 (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N',
1516 refcount_read(&tunnel->ref_count) - 1);
1517 seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1518 0,
1519 atomic_long_read(&tunnel->stats.tx_packets),
1520 atomic_long_read(&tunnel->stats.tx_bytes),
1521 atomic_long_read(&tunnel->stats.tx_errors),
1522 atomic_long_read(&tunnel->stats.rx_packets),
1523 atomic_long_read(&tunnel->stats.rx_bytes),
1524 atomic_long_read(&tunnel->stats.rx_errors));
1525 }
1526
pppol2tp_seq_session_show(struct seq_file * m,void * v)1527 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1528 {
1529 struct l2tp_session *session = v;
1530 struct l2tp_tunnel *tunnel = session->tunnel;
1531 unsigned char state;
1532 char user_data_ok;
1533 struct sock *sk;
1534 u32 ip = 0;
1535 u16 port = 0;
1536
1537 if (tunnel->sock) {
1538 struct inet_sock *inet = inet_sk(tunnel->sock);
1539
1540 ip = ntohl(inet->inet_saddr);
1541 port = ntohs(inet->inet_sport);
1542 }
1543
1544 sk = pppol2tp_session_get_sock(session);
1545 if (sk) {
1546 state = sk->sk_state;
1547 user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';
1548 } else {
1549 state = 0;
1550 user_data_ok = 'N';
1551 }
1552
1553 seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> %04X/%04X %d %c\n",
1554 session->name, ip, port,
1555 tunnel->tunnel_id,
1556 session->session_id,
1557 tunnel->peer_tunnel_id,
1558 session->peer_session_id,
1559 state, user_data_ok);
1560 seq_printf(m, " 0/0/%c/%c/%s %08x %u\n",
1561 session->recv_seq ? 'R' : '-',
1562 session->send_seq ? 'S' : '-',
1563 session->lns_mode ? "LNS" : "LAC",
1564 0,
1565 jiffies_to_msecs(session->reorder_timeout));
1566 seq_printf(m, " %hu/%hu %ld/%ld/%ld %ld/%ld/%ld\n",
1567 session->nr, session->ns,
1568 atomic_long_read(&session->stats.tx_packets),
1569 atomic_long_read(&session->stats.tx_bytes),
1570 atomic_long_read(&session->stats.tx_errors),
1571 atomic_long_read(&session->stats.rx_packets),
1572 atomic_long_read(&session->stats.rx_bytes),
1573 atomic_long_read(&session->stats.rx_errors));
1574
1575 if (sk) {
1576 struct pppox_sock *po = pppox_sk(sk);
1577
1578 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
1579 sock_put(sk);
1580 }
1581 }
1582
pppol2tp_seq_show(struct seq_file * m,void * v)1583 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1584 {
1585 struct pppol2tp_seq_data *pd = v;
1586
1587 /* display header on line 1 */
1588 if (v == SEQ_START_TOKEN) {
1589 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1590 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1591 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1592 seq_puts(m, " SESSION name, addr/port src-tid/sid dest-tid/sid state user-data-ok\n");
1593 seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1594 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1595 goto out;
1596 }
1597
1598 if (!pd->session)
1599 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1600 else
1601 pppol2tp_seq_session_show(m, pd->session);
1602
1603 out:
1604 return 0;
1605 }
1606
1607 static const struct seq_operations pppol2tp_seq_ops = {
1608 .start = pppol2tp_seq_start,
1609 .next = pppol2tp_seq_next,
1610 .stop = pppol2tp_seq_stop,
1611 .show = pppol2tp_seq_show,
1612 };
1613 #endif /* CONFIG_PROC_FS */
1614
1615 /*****************************************************************************
1616 * Network namespace
1617 *****************************************************************************/
1618
pppol2tp_init_net(struct net * net)1619 static __net_init int pppol2tp_init_net(struct net *net)
1620 {
1621 struct proc_dir_entry *pde;
1622 int err = 0;
1623
1624 pde = proc_create_net("pppol2tp", 0444, net->proc_net,
1625 &pppol2tp_seq_ops, sizeof(struct pppol2tp_seq_data));
1626 if (!pde) {
1627 err = -ENOMEM;
1628 goto out;
1629 }
1630
1631 out:
1632 return err;
1633 }
1634
pppol2tp_exit_net(struct net * net)1635 static __net_exit void pppol2tp_exit_net(struct net *net)
1636 {
1637 remove_proc_entry("pppol2tp", net->proc_net);
1638 }
1639
1640 static struct pernet_operations pppol2tp_net_ops = {
1641 .init = pppol2tp_init_net,
1642 .exit = pppol2tp_exit_net,
1643 .id = &pppol2tp_net_id,
1644 };
1645
1646 /*****************************************************************************
1647 * Init and cleanup
1648 *****************************************************************************/
1649
1650 static const struct proto_ops pppol2tp_ops = {
1651 .family = AF_PPPOX,
1652 .owner = THIS_MODULE,
1653 .release = pppol2tp_release,
1654 .bind = sock_no_bind,
1655 .connect = pppol2tp_connect,
1656 .socketpair = sock_no_socketpair,
1657 .accept = sock_no_accept,
1658 .getname = pppol2tp_getname,
1659 .poll = datagram_poll,
1660 .listen = sock_no_listen,
1661 .shutdown = sock_no_shutdown,
1662 .setsockopt = pppol2tp_setsockopt,
1663 .getsockopt = pppol2tp_getsockopt,
1664 .sendmsg = pppol2tp_sendmsg,
1665 .recvmsg = pppol2tp_recvmsg,
1666 .mmap = sock_no_mmap,
1667 .ioctl = pppox_ioctl,
1668 #ifdef CONFIG_COMPAT
1669 .compat_ioctl = pppox_compat_ioctl,
1670 #endif
1671 };
1672
1673 static const struct pppox_proto pppol2tp_proto = {
1674 .create = pppol2tp_create,
1675 .ioctl = pppol2tp_ioctl,
1676 .owner = THIS_MODULE,
1677 };
1678
1679 #ifdef CONFIG_L2TP_V3
1680
1681 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1682 .session_create = pppol2tp_session_create,
1683 .session_delete = l2tp_session_delete,
1684 };
1685
1686 #endif /* CONFIG_L2TP_V3 */
1687
pppol2tp_init(void)1688 static int __init pppol2tp_init(void)
1689 {
1690 int err;
1691
1692 err = register_pernet_device(&pppol2tp_net_ops);
1693 if (err)
1694 goto out;
1695
1696 err = proto_register(&pppol2tp_sk_proto, 0);
1697 if (err)
1698 goto out_unregister_pppol2tp_pernet;
1699
1700 err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1701 if (err)
1702 goto out_unregister_pppol2tp_proto;
1703
1704 #ifdef CONFIG_L2TP_V3
1705 err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1706 if (err)
1707 goto out_unregister_pppox;
1708 #endif
1709
1710 pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1711
1712 out:
1713 return err;
1714
1715 #ifdef CONFIG_L2TP_V3
1716 out_unregister_pppox:
1717 unregister_pppox_proto(PX_PROTO_OL2TP);
1718 #endif
1719 out_unregister_pppol2tp_proto:
1720 proto_unregister(&pppol2tp_sk_proto);
1721 out_unregister_pppol2tp_pernet:
1722 unregister_pernet_device(&pppol2tp_net_ops);
1723 goto out;
1724 }
1725
pppol2tp_exit(void)1726 static void __exit pppol2tp_exit(void)
1727 {
1728 #ifdef CONFIG_L2TP_V3
1729 l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1730 #endif
1731 unregister_pppox_proto(PX_PROTO_OL2TP);
1732 proto_unregister(&pppol2tp_sk_proto);
1733 unregister_pernet_device(&pppol2tp_net_ops);
1734 }
1735
1736 module_init(pppol2tp_init);
1737 module_exit(pppol2tp_exit);
1738
1739 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1740 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1741 MODULE_LICENSE("GPL");
1742 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1743 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OL2TP);
1744 MODULE_ALIAS_L2TP_PWTYPE(7);
1745