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