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
653 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
654 */
pppol2tp_connect(struct socket * sock,struct sockaddr * uservaddr,int sockaddr_len,int flags)655 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
656 int sockaddr_len, int flags)
657 {
658 struct sock *sk = sock->sk;
659 struct pppox_sock *po = pppox_sk(sk);
660 struct l2tp_session *session = NULL;
661 struct l2tp_connect_info info;
662 struct l2tp_tunnel *tunnel;
663 struct pppol2tp_session *ps;
664 struct l2tp_session_cfg cfg = { 0, };
665 bool drop_refcnt = false;
666 bool drop_tunnel = false;
667 bool new_session = false;
668 bool new_tunnel = false;
669 int error;
670
671 error = pppol2tp_sockaddr_get_info(uservaddr, sockaddr_len, &info);
672 if (error < 0)
673 return error;
674
675 lock_sock(sk);
676
677 /* Check for already bound sockets */
678 error = -EBUSY;
679 if (sk->sk_state & PPPOX_CONNECTED)
680 goto end;
681
682 /* We don't supporting rebinding anyway */
683 error = -EALREADY;
684 if (sk->sk_user_data)
685 goto end; /* socket is already attached */
686
687 /* Don't bind if tunnel_id is 0 */
688 error = -EINVAL;
689 if (!info.tunnel_id)
690 goto end;
691
692 tunnel = l2tp_tunnel_get(sock_net(sk), info.tunnel_id);
693 if (tunnel)
694 drop_tunnel = true;
695
696 /* Special case: create tunnel context if session_id and
697 * peer_session_id is 0. Otherwise look up tunnel using supplied
698 * tunnel id.
699 */
700 if (!info.session_id && !info.peer_session_id) {
701 if (!tunnel) {
702 struct l2tp_tunnel_cfg tcfg = {
703 .encap = L2TP_ENCAPTYPE_UDP,
704 };
705
706 /* Prevent l2tp_tunnel_register() from trying to set up
707 * a kernel socket.
708 */
709 if (info.fd < 0) {
710 error = -EBADF;
711 goto end;
712 }
713
714 error = l2tp_tunnel_create(info.fd,
715 info.version,
716 info.tunnel_id,
717 info.peer_tunnel_id, &tcfg,
718 &tunnel);
719 if (error < 0)
720 goto end;
721
722 l2tp_tunnel_inc_refcount(tunnel);
723 error = l2tp_tunnel_register(tunnel, sock_net(sk),
724 &tcfg);
725 if (error < 0) {
726 kfree(tunnel);
727 goto end;
728 }
729 drop_tunnel = true;
730 new_tunnel = true;
731 }
732 } else {
733 /* Error if we can't find the tunnel */
734 error = -ENOENT;
735 if (!tunnel)
736 goto end;
737
738 /* Error if socket is not prepped */
739 if (!tunnel->sock)
740 goto end;
741 }
742
743 if (tunnel->peer_tunnel_id == 0)
744 tunnel->peer_tunnel_id = info.peer_tunnel_id;
745
746 session = l2tp_tunnel_get_session(tunnel, info.session_id);
747 if (session) {
748 drop_refcnt = true;
749
750 if (session->pwtype != L2TP_PWTYPE_PPP) {
751 error = -EPROTOTYPE;
752 goto end;
753 }
754
755 ps = l2tp_session_priv(session);
756
757 /* Using a pre-existing session is fine as long as it hasn't
758 * been connected yet.
759 */
760 mutex_lock(&ps->sk_lock);
761 if (rcu_dereference_protected(ps->sk,
762 lockdep_is_held(&ps->sk_lock)) ||
763 ps->__sk) {
764 mutex_unlock(&ps->sk_lock);
765 error = -EEXIST;
766 goto end;
767 }
768 } else {
769 cfg.pw_type = L2TP_PWTYPE_PPP;
770
771 session = l2tp_session_create(sizeof(struct pppol2tp_session),
772 tunnel, info.session_id,
773 info.peer_session_id, &cfg);
774 if (IS_ERR(session)) {
775 error = PTR_ERR(session);
776 goto end;
777 }
778
779 pppol2tp_session_init(session);
780 ps = l2tp_session_priv(session);
781 l2tp_session_inc_refcount(session);
782
783 mutex_lock(&ps->sk_lock);
784 error = l2tp_session_register(session, tunnel);
785 if (error < 0) {
786 mutex_unlock(&ps->sk_lock);
787 kfree(session);
788 goto end;
789 }
790 drop_refcnt = true;
791 new_session = true;
792 }
793
794 /* Special case: if source & dest session_id == 0x0000, this
795 * socket is being created to manage the tunnel. Just set up
796 * the internal context for use by ioctl() and sockopt()
797 * handlers.
798 */
799 if (session->session_id == 0 && session->peer_session_id == 0) {
800 error = 0;
801 goto out_no_ppp;
802 }
803
804 /* The only header we need to worry about is the L2TP
805 * header. This size is different depending on whether
806 * sequence numbers are enabled for the data channel.
807 */
808 po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
809
810 po->chan.private = sk;
811 po->chan.ops = &pppol2tp_chan_ops;
812 po->chan.mtu = pppol2tp_tunnel_mtu(tunnel);
813
814 error = ppp_register_net_channel(sock_net(sk), &po->chan);
815 if (error) {
816 mutex_unlock(&ps->sk_lock);
817 goto end;
818 }
819
820 out_no_ppp:
821 /* This is how we get the session context from the socket. */
822 sk->sk_user_data = session;
823 rcu_assign_pointer(ps->sk, sk);
824 mutex_unlock(&ps->sk_lock);
825
826 /* Keep the reference we've grabbed on the session: sk doesn't expect
827 * the session to disappear. pppol2tp_session_destruct() is responsible
828 * for dropping it.
829 */
830 drop_refcnt = false;
831
832 sk->sk_state = PPPOX_CONNECTED;
833
834 end:
835 if (error) {
836 if (new_session)
837 l2tp_session_delete(session);
838 if (new_tunnel)
839 l2tp_tunnel_delete(tunnel);
840 }
841 if (drop_refcnt)
842 l2tp_session_dec_refcount(session);
843 if (drop_tunnel)
844 l2tp_tunnel_dec_refcount(tunnel);
845 release_sock(sk);
846
847 return error;
848 }
849
850 #ifdef CONFIG_L2TP_V3
851
852 /* 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)853 static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
854 u32 session_id, u32 peer_session_id,
855 struct l2tp_session_cfg *cfg)
856 {
857 int error;
858 struct l2tp_session *session;
859
860 /* Error if tunnel socket is not prepped */
861 if (!tunnel->sock) {
862 error = -ENOENT;
863 goto err;
864 }
865
866 /* Allocate and initialize a new session context. */
867 session = l2tp_session_create(sizeof(struct pppol2tp_session),
868 tunnel, session_id,
869 peer_session_id, cfg);
870 if (IS_ERR(session)) {
871 error = PTR_ERR(session);
872 goto err;
873 }
874
875 pppol2tp_session_init(session);
876
877 error = l2tp_session_register(session, tunnel);
878 if (error < 0)
879 goto err_sess;
880
881 return 0;
882
883 err_sess:
884 kfree(session);
885 err:
886 return error;
887 }
888
889 #endif /* CONFIG_L2TP_V3 */
890
891 /* getname() support.
892 */
pppol2tp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)893 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
894 int peer)
895 {
896 int len = 0;
897 int error = 0;
898 struct l2tp_session *session;
899 struct l2tp_tunnel *tunnel;
900 struct sock *sk = sock->sk;
901 struct inet_sock *inet;
902 struct pppol2tp_session *pls;
903
904 error = -ENOTCONN;
905 if (!sk)
906 goto end;
907 if (!(sk->sk_state & PPPOX_CONNECTED))
908 goto end;
909
910 error = -EBADF;
911 session = pppol2tp_sock_to_session(sk);
912 if (!session)
913 goto end;
914
915 pls = l2tp_session_priv(session);
916 tunnel = session->tunnel;
917
918 inet = inet_sk(tunnel->sock);
919 if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET) {
920 struct sockaddr_pppol2tp sp;
921
922 len = sizeof(sp);
923 memset(&sp, 0, len);
924 sp.sa_family = AF_PPPOX;
925 sp.sa_protocol = PX_PROTO_OL2TP;
926 sp.pppol2tp.fd = tunnel->fd;
927 sp.pppol2tp.pid = pls->owner;
928 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
929 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
930 sp.pppol2tp.s_session = session->session_id;
931 sp.pppol2tp.d_session = session->peer_session_id;
932 sp.pppol2tp.addr.sin_family = AF_INET;
933 sp.pppol2tp.addr.sin_port = inet->inet_dport;
934 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
935 memcpy(uaddr, &sp, len);
936 #if IS_ENABLED(CONFIG_IPV6)
937 } else if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET6) {
938 struct sockaddr_pppol2tpin6 sp;
939
940 len = sizeof(sp);
941 memset(&sp, 0, len);
942 sp.sa_family = AF_PPPOX;
943 sp.sa_protocol = PX_PROTO_OL2TP;
944 sp.pppol2tp.fd = tunnel->fd;
945 sp.pppol2tp.pid = pls->owner;
946 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
947 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
948 sp.pppol2tp.s_session = session->session_id;
949 sp.pppol2tp.d_session = session->peer_session_id;
950 sp.pppol2tp.addr.sin6_family = AF_INET6;
951 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
952 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
953 sizeof(tunnel->sock->sk_v6_daddr));
954 memcpy(uaddr, &sp, len);
955 } else if (tunnel->version == 3 && tunnel->sock->sk_family == AF_INET6) {
956 struct sockaddr_pppol2tpv3in6 sp;
957
958 len = sizeof(sp);
959 memset(&sp, 0, len);
960 sp.sa_family = AF_PPPOX;
961 sp.sa_protocol = PX_PROTO_OL2TP;
962 sp.pppol2tp.fd = tunnel->fd;
963 sp.pppol2tp.pid = pls->owner;
964 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
965 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
966 sp.pppol2tp.s_session = session->session_id;
967 sp.pppol2tp.d_session = session->peer_session_id;
968 sp.pppol2tp.addr.sin6_family = AF_INET6;
969 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
970 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
971 sizeof(tunnel->sock->sk_v6_daddr));
972 memcpy(uaddr, &sp, len);
973 #endif
974 } else if (tunnel->version == 3) {
975 struct sockaddr_pppol2tpv3 sp;
976
977 len = sizeof(sp);
978 memset(&sp, 0, len);
979 sp.sa_family = AF_PPPOX;
980 sp.sa_protocol = PX_PROTO_OL2TP;
981 sp.pppol2tp.fd = tunnel->fd;
982 sp.pppol2tp.pid = pls->owner;
983 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
984 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
985 sp.pppol2tp.s_session = session->session_id;
986 sp.pppol2tp.d_session = session->peer_session_id;
987 sp.pppol2tp.addr.sin_family = AF_INET;
988 sp.pppol2tp.addr.sin_port = inet->inet_dport;
989 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
990 memcpy(uaddr, &sp, len);
991 }
992
993 error = len;
994
995 sock_put(sk);
996 end:
997 return error;
998 }
999
1000 /****************************************************************************
1001 * ioctl() handlers.
1002 *
1003 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1004 * sockets. However, in order to control kernel tunnel features, we allow
1005 * userspace to create a special "tunnel" PPPoX socket which is used for
1006 * control only. Tunnel PPPoX sockets have session_id == 0 and simply allow
1007 * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1008 * calls.
1009 ****************************************************************************/
1010
pppol2tp_copy_stats(struct pppol2tp_ioc_stats * dest,const struct l2tp_stats * stats)1011 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
1012 const struct l2tp_stats *stats)
1013 {
1014 memset(dest, 0, sizeof(*dest));
1015
1016 dest->tx_packets = atomic_long_read(&stats->tx_packets);
1017 dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
1018 dest->tx_errors = atomic_long_read(&stats->tx_errors);
1019 dest->rx_packets = atomic_long_read(&stats->rx_packets);
1020 dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
1021 dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
1022 dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
1023 dest->rx_errors = atomic_long_read(&stats->rx_errors);
1024 }
1025
pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats * stats,struct l2tp_tunnel * tunnel)1026 static int pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats *stats,
1027 struct l2tp_tunnel *tunnel)
1028 {
1029 struct l2tp_session *session;
1030
1031 if (!stats->session_id) {
1032 pppol2tp_copy_stats(stats, &tunnel->stats);
1033 return 0;
1034 }
1035
1036 /* If session_id is set, search the corresponding session in the
1037 * context of this tunnel and record the session's statistics.
1038 */
1039 session = l2tp_tunnel_get_session(tunnel, stats->session_id);
1040 if (!session)
1041 return -EBADR;
1042
1043 if (session->pwtype != L2TP_PWTYPE_PPP) {
1044 l2tp_session_dec_refcount(session);
1045 return -EBADR;
1046 }
1047
1048 pppol2tp_copy_stats(stats, &session->stats);
1049 l2tp_session_dec_refcount(session);
1050
1051 return 0;
1052 }
1053
pppol2tp_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)1054 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1055 unsigned long arg)
1056 {
1057 struct pppol2tp_ioc_stats stats;
1058 struct l2tp_session *session;
1059
1060 switch (cmd) {
1061 case PPPIOCGMRU:
1062 case PPPIOCGFLAGS:
1063 session = sock->sk->sk_user_data;
1064 if (!session)
1065 return -ENOTCONN;
1066
1067 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1068 return -EBADF;
1069
1070 /* Not defined for tunnels */
1071 if (!session->session_id && !session->peer_session_id)
1072 return -ENOSYS;
1073
1074 if (put_user(0, (int __user *)arg))
1075 return -EFAULT;
1076 break;
1077
1078 case PPPIOCSMRU:
1079 case PPPIOCSFLAGS:
1080 session = sock->sk->sk_user_data;
1081 if (!session)
1082 return -ENOTCONN;
1083
1084 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1085 return -EBADF;
1086
1087 /* Not defined for tunnels */
1088 if (!session->session_id && !session->peer_session_id)
1089 return -ENOSYS;
1090
1091 if (!access_ok((int __user *)arg, sizeof(int)))
1092 return -EFAULT;
1093 break;
1094
1095 case PPPIOCGL2TPSTATS:
1096 session = sock->sk->sk_user_data;
1097 if (!session)
1098 return -ENOTCONN;
1099
1100 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1101 return -EBADF;
1102
1103 /* Session 0 represents the parent tunnel */
1104 if (!session->session_id && !session->peer_session_id) {
1105 u32 session_id;
1106 int err;
1107
1108 if (copy_from_user(&stats, (void __user *)arg,
1109 sizeof(stats)))
1110 return -EFAULT;
1111
1112 session_id = stats.session_id;
1113 err = pppol2tp_tunnel_copy_stats(&stats,
1114 session->tunnel);
1115 if (err < 0)
1116 return err;
1117
1118 stats.session_id = session_id;
1119 } else {
1120 pppol2tp_copy_stats(&stats, &session->stats);
1121 stats.session_id = session->session_id;
1122 }
1123 stats.tunnel_id = session->tunnel->tunnel_id;
1124 stats.using_ipsec = l2tp_tunnel_uses_xfrm(session->tunnel);
1125
1126 if (copy_to_user((void __user *)arg, &stats, sizeof(stats)))
1127 return -EFAULT;
1128 break;
1129
1130 default:
1131 return -ENOIOCTLCMD;
1132 }
1133
1134 return 0;
1135 }
1136
1137 /*****************************************************************************
1138 * setsockopt() / getsockopt() support.
1139 *
1140 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1141 * sockets. In order to control kernel tunnel features, we allow userspace to
1142 * create a special "tunnel" PPPoX socket which is used for control only.
1143 * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1144 * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1145 *****************************************************************************/
1146
1147 /* Tunnel setsockopt() helper.
1148 */
pppol2tp_tunnel_setsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int val)1149 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1150 struct l2tp_tunnel *tunnel,
1151 int optname, int val)
1152 {
1153 int err = 0;
1154
1155 switch (optname) {
1156 case PPPOL2TP_SO_DEBUG:
1157 /* Tunnel debug flags option is deprecated */
1158 break;
1159
1160 default:
1161 err = -ENOPROTOOPT;
1162 break;
1163 }
1164
1165 return err;
1166 }
1167
1168 /* Session setsockopt helper.
1169 */
pppol2tp_session_setsockopt(struct sock * sk,struct l2tp_session * session,int optname,int val)1170 static int pppol2tp_session_setsockopt(struct sock *sk,
1171 struct l2tp_session *session,
1172 int optname, int val)
1173 {
1174 int err = 0;
1175
1176 switch (optname) {
1177 case PPPOL2TP_SO_RECVSEQ:
1178 if (val != 0 && val != 1) {
1179 err = -EINVAL;
1180 break;
1181 }
1182 session->recv_seq = !!val;
1183 break;
1184
1185 case PPPOL2TP_SO_SENDSEQ:
1186 if (val != 0 && val != 1) {
1187 err = -EINVAL;
1188 break;
1189 }
1190 session->send_seq = !!val;
1191 {
1192 struct pppox_sock *po = pppox_sk(sk);
1193
1194 po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1195 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1196 }
1197 l2tp_session_set_header_len(session, session->tunnel->version);
1198 break;
1199
1200 case PPPOL2TP_SO_LNSMODE:
1201 if (val != 0 && val != 1) {
1202 err = -EINVAL;
1203 break;
1204 }
1205 session->lns_mode = !!val;
1206 break;
1207
1208 case PPPOL2TP_SO_DEBUG:
1209 /* Session debug flags option is deprecated */
1210 break;
1211
1212 case PPPOL2TP_SO_REORDERTO:
1213 session->reorder_timeout = msecs_to_jiffies(val);
1214 break;
1215
1216 default:
1217 err = -ENOPROTOOPT;
1218 break;
1219 }
1220
1221 return err;
1222 }
1223
1224 /* Main setsockopt() entry point.
1225 * Does API checks, then calls either the tunnel or session setsockopt
1226 * handler, according to whether the PPPoL2TP socket is a for a regular
1227 * session or the special tunnel type.
1228 */
pppol2tp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1229 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1230 sockptr_t optval, unsigned int optlen)
1231 {
1232 struct sock *sk = sock->sk;
1233 struct l2tp_session *session;
1234 struct l2tp_tunnel *tunnel;
1235 int val;
1236 int err;
1237
1238 if (level != SOL_PPPOL2TP)
1239 return -EINVAL;
1240
1241 if (optlen < sizeof(int))
1242 return -EINVAL;
1243
1244 if (copy_from_sockptr(&val, optval, sizeof(int)))
1245 return -EFAULT;
1246
1247 err = -ENOTCONN;
1248 if (!sk->sk_user_data)
1249 goto end;
1250
1251 /* Get session context from the socket */
1252 err = -EBADF;
1253 session = pppol2tp_sock_to_session(sk);
1254 if (!session)
1255 goto end;
1256
1257 /* Special case: if session_id == 0x0000, treat as operation on tunnel
1258 */
1259 if (session->session_id == 0 && session->peer_session_id == 0) {
1260 tunnel = session->tunnel;
1261 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1262 } else {
1263 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1264 }
1265
1266 sock_put(sk);
1267 end:
1268 return err;
1269 }
1270
1271 /* Tunnel getsockopt helper. Called with sock locked.
1272 */
pppol2tp_tunnel_getsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int * val)1273 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1274 struct l2tp_tunnel *tunnel,
1275 int optname, int *val)
1276 {
1277 int err = 0;
1278
1279 switch (optname) {
1280 case PPPOL2TP_SO_DEBUG:
1281 /* Tunnel debug flags option is deprecated */
1282 *val = 0;
1283 break;
1284
1285 default:
1286 err = -ENOPROTOOPT;
1287 break;
1288 }
1289
1290 return err;
1291 }
1292
1293 /* Session getsockopt helper. Called with sock locked.
1294 */
pppol2tp_session_getsockopt(struct sock * sk,struct l2tp_session * session,int optname,int * val)1295 static int pppol2tp_session_getsockopt(struct sock *sk,
1296 struct l2tp_session *session,
1297 int optname, int *val)
1298 {
1299 int err = 0;
1300
1301 switch (optname) {
1302 case PPPOL2TP_SO_RECVSEQ:
1303 *val = session->recv_seq;
1304 break;
1305
1306 case PPPOL2TP_SO_SENDSEQ:
1307 *val = session->send_seq;
1308 break;
1309
1310 case PPPOL2TP_SO_LNSMODE:
1311 *val = session->lns_mode;
1312 break;
1313
1314 case PPPOL2TP_SO_DEBUG:
1315 /* Session debug flags option is deprecated */
1316 *val = 0;
1317 break;
1318
1319 case PPPOL2TP_SO_REORDERTO:
1320 *val = (int)jiffies_to_msecs(session->reorder_timeout);
1321 break;
1322
1323 default:
1324 err = -ENOPROTOOPT;
1325 }
1326
1327 return err;
1328 }
1329
1330 /* Main getsockopt() entry point.
1331 * Does API checks, then calls either the tunnel or session getsockopt
1332 * handler, according to whether the PPPoX socket is a for a regular session
1333 * or the special tunnel type.
1334 */
pppol2tp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1335 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1336 char __user *optval, int __user *optlen)
1337 {
1338 struct sock *sk = sock->sk;
1339 struct l2tp_session *session;
1340 struct l2tp_tunnel *tunnel;
1341 int val, len;
1342 int err;
1343
1344 if (level != SOL_PPPOL2TP)
1345 return -EINVAL;
1346
1347 if (get_user(len, optlen))
1348 return -EFAULT;
1349
1350 len = min_t(unsigned int, len, sizeof(int));
1351
1352 if (len < 0)
1353 return -EINVAL;
1354
1355 err = -ENOTCONN;
1356 if (!sk->sk_user_data)
1357 goto end;
1358
1359 /* Get the session context */
1360 err = -EBADF;
1361 session = pppol2tp_sock_to_session(sk);
1362 if (!session)
1363 goto end;
1364
1365 /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1366 if (session->session_id == 0 && session->peer_session_id == 0) {
1367 tunnel = session->tunnel;
1368 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1369 if (err)
1370 goto end_put_sess;
1371 } else {
1372 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1373 if (err)
1374 goto end_put_sess;
1375 }
1376
1377 err = -EFAULT;
1378 if (put_user(len, optlen))
1379 goto end_put_sess;
1380
1381 if (copy_to_user((void __user *)optval, &val, len))
1382 goto end_put_sess;
1383
1384 err = 0;
1385
1386 end_put_sess:
1387 sock_put(sk);
1388 end:
1389 return err;
1390 }
1391
1392 /*****************************************************************************
1393 * /proc filesystem for debug
1394 * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1395 * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1396 *****************************************************************************/
1397
1398 static unsigned int pppol2tp_net_id;
1399
1400 #ifdef CONFIG_PROC_FS
1401
1402 struct pppol2tp_seq_data {
1403 struct seq_net_private p;
1404 int tunnel_idx; /* current tunnel */
1405 int session_idx; /* index of session within current tunnel */
1406 struct l2tp_tunnel *tunnel;
1407 struct l2tp_session *session; /* NULL means get next tunnel */
1408 };
1409
pppol2tp_next_tunnel(struct net * net,struct pppol2tp_seq_data * pd)1410 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1411 {
1412 /* Drop reference taken during previous invocation */
1413 if (pd->tunnel)
1414 l2tp_tunnel_dec_refcount(pd->tunnel);
1415
1416 for (;;) {
1417 pd->tunnel = l2tp_tunnel_get_nth(net, pd->tunnel_idx);
1418 pd->tunnel_idx++;
1419
1420 /* Only accept L2TPv2 tunnels */
1421 if (!pd->tunnel || pd->tunnel->version == 2)
1422 return;
1423
1424 l2tp_tunnel_dec_refcount(pd->tunnel);
1425 }
1426 }
1427
pppol2tp_next_session(struct net * net,struct pppol2tp_seq_data * pd)1428 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1429 {
1430 /* Drop reference taken during previous invocation */
1431 if (pd->session)
1432 l2tp_session_dec_refcount(pd->session);
1433
1434 pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
1435 pd->session_idx++;
1436
1437 if (!pd->session) {
1438 pd->session_idx = 0;
1439 pppol2tp_next_tunnel(net, pd);
1440 }
1441 }
1442
pppol2tp_seq_start(struct seq_file * m,loff_t * offs)1443 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1444 {
1445 struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1446 loff_t pos = *offs;
1447 struct net *net;
1448
1449 if (!pos)
1450 goto out;
1451
1452 if (WARN_ON(!m->private)) {
1453 pd = NULL;
1454 goto out;
1455 }
1456
1457 pd = m->private;
1458 net = seq_file_net(m);
1459
1460 if (!pd->tunnel)
1461 pppol2tp_next_tunnel(net, pd);
1462 else
1463 pppol2tp_next_session(net, pd);
1464
1465 /* NULL tunnel and session indicates end of list */
1466 if (!pd->tunnel && !pd->session)
1467 pd = NULL;
1468
1469 out:
1470 return pd;
1471 }
1472
pppol2tp_seq_next(struct seq_file * m,void * v,loff_t * pos)1473 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1474 {
1475 (*pos)++;
1476 return NULL;
1477 }
1478
pppol2tp_seq_stop(struct seq_file * p,void * v)1479 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1480 {
1481 struct pppol2tp_seq_data *pd = v;
1482
1483 if (!pd || pd == SEQ_START_TOKEN)
1484 return;
1485
1486 /* Drop reference taken by last invocation of pppol2tp_next_session()
1487 * or pppol2tp_next_tunnel().
1488 */
1489 if (pd->session) {
1490 l2tp_session_dec_refcount(pd->session);
1491 pd->session = NULL;
1492 }
1493 if (pd->tunnel) {
1494 l2tp_tunnel_dec_refcount(pd->tunnel);
1495 pd->tunnel = NULL;
1496 }
1497 }
1498
pppol2tp_seq_tunnel_show(struct seq_file * m,void * v)1499 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1500 {
1501 struct l2tp_tunnel *tunnel = v;
1502
1503 seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1504 tunnel->name,
1505 (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N',
1506 refcount_read(&tunnel->ref_count) - 1);
1507 seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1508 0,
1509 atomic_long_read(&tunnel->stats.tx_packets),
1510 atomic_long_read(&tunnel->stats.tx_bytes),
1511 atomic_long_read(&tunnel->stats.tx_errors),
1512 atomic_long_read(&tunnel->stats.rx_packets),
1513 atomic_long_read(&tunnel->stats.rx_bytes),
1514 atomic_long_read(&tunnel->stats.rx_errors));
1515 }
1516
pppol2tp_seq_session_show(struct seq_file * m,void * v)1517 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1518 {
1519 struct l2tp_session *session = v;
1520 struct l2tp_tunnel *tunnel = session->tunnel;
1521 unsigned char state;
1522 char user_data_ok;
1523 struct sock *sk;
1524 u32 ip = 0;
1525 u16 port = 0;
1526
1527 if (tunnel->sock) {
1528 struct inet_sock *inet = inet_sk(tunnel->sock);
1529
1530 ip = ntohl(inet->inet_saddr);
1531 port = ntohs(inet->inet_sport);
1532 }
1533
1534 sk = pppol2tp_session_get_sock(session);
1535 if (sk) {
1536 state = sk->sk_state;
1537 user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';
1538 } else {
1539 state = 0;
1540 user_data_ok = 'N';
1541 }
1542
1543 seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> %04X/%04X %d %c\n",
1544 session->name, ip, port,
1545 tunnel->tunnel_id,
1546 session->session_id,
1547 tunnel->peer_tunnel_id,
1548 session->peer_session_id,
1549 state, user_data_ok);
1550 seq_printf(m, " 0/0/%c/%c/%s %08x %u\n",
1551 session->recv_seq ? 'R' : '-',
1552 session->send_seq ? 'S' : '-',
1553 session->lns_mode ? "LNS" : "LAC",
1554 0,
1555 jiffies_to_msecs(session->reorder_timeout));
1556 seq_printf(m, " %u/%u %ld/%ld/%ld %ld/%ld/%ld\n",
1557 session->nr, session->ns,
1558 atomic_long_read(&session->stats.tx_packets),
1559 atomic_long_read(&session->stats.tx_bytes),
1560 atomic_long_read(&session->stats.tx_errors),
1561 atomic_long_read(&session->stats.rx_packets),
1562 atomic_long_read(&session->stats.rx_bytes),
1563 atomic_long_read(&session->stats.rx_errors));
1564
1565 if (sk) {
1566 struct pppox_sock *po = pppox_sk(sk);
1567
1568 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
1569 sock_put(sk);
1570 }
1571 }
1572
pppol2tp_seq_show(struct seq_file * m,void * v)1573 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1574 {
1575 struct pppol2tp_seq_data *pd = v;
1576
1577 /* display header on line 1 */
1578 if (v == SEQ_START_TOKEN) {
1579 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1580 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1581 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1582 seq_puts(m, " SESSION name, addr/port src-tid/sid dest-tid/sid state user-data-ok\n");
1583 seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1584 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1585 goto out;
1586 }
1587
1588 if (!pd->session)
1589 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1590 else
1591 pppol2tp_seq_session_show(m, pd->session);
1592
1593 out:
1594 return 0;
1595 }
1596
1597 static const struct seq_operations pppol2tp_seq_ops = {
1598 .start = pppol2tp_seq_start,
1599 .next = pppol2tp_seq_next,
1600 .stop = pppol2tp_seq_stop,
1601 .show = pppol2tp_seq_show,
1602 };
1603 #endif /* CONFIG_PROC_FS */
1604
1605 /*****************************************************************************
1606 * Network namespace
1607 *****************************************************************************/
1608
pppol2tp_init_net(struct net * net)1609 static __net_init int pppol2tp_init_net(struct net *net)
1610 {
1611 struct proc_dir_entry *pde;
1612 int err = 0;
1613
1614 pde = proc_create_net("pppol2tp", 0444, net->proc_net,
1615 &pppol2tp_seq_ops, sizeof(struct pppol2tp_seq_data));
1616 if (!pde) {
1617 err = -ENOMEM;
1618 goto out;
1619 }
1620
1621 out:
1622 return err;
1623 }
1624
pppol2tp_exit_net(struct net * net)1625 static __net_exit void pppol2tp_exit_net(struct net *net)
1626 {
1627 remove_proc_entry("pppol2tp", net->proc_net);
1628 }
1629
1630 static struct pernet_operations pppol2tp_net_ops = {
1631 .init = pppol2tp_init_net,
1632 .exit = pppol2tp_exit_net,
1633 .id = &pppol2tp_net_id,
1634 };
1635
1636 /*****************************************************************************
1637 * Init and cleanup
1638 *****************************************************************************/
1639
1640 static const struct proto_ops pppol2tp_ops = {
1641 .family = AF_PPPOX,
1642 .owner = THIS_MODULE,
1643 .release = pppol2tp_release,
1644 .bind = sock_no_bind,
1645 .connect = pppol2tp_connect,
1646 .socketpair = sock_no_socketpair,
1647 .accept = sock_no_accept,
1648 .getname = pppol2tp_getname,
1649 .poll = datagram_poll,
1650 .listen = sock_no_listen,
1651 .shutdown = sock_no_shutdown,
1652 .setsockopt = pppol2tp_setsockopt,
1653 .getsockopt = pppol2tp_getsockopt,
1654 .sendmsg = pppol2tp_sendmsg,
1655 .recvmsg = pppol2tp_recvmsg,
1656 .mmap = sock_no_mmap,
1657 .ioctl = pppox_ioctl,
1658 #ifdef CONFIG_COMPAT
1659 .compat_ioctl = pppox_compat_ioctl,
1660 #endif
1661 };
1662
1663 static const struct pppox_proto pppol2tp_proto = {
1664 .create = pppol2tp_create,
1665 .ioctl = pppol2tp_ioctl,
1666 .owner = THIS_MODULE,
1667 };
1668
1669 #ifdef CONFIG_L2TP_V3
1670
1671 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1672 .session_create = pppol2tp_session_create,
1673 .session_delete = l2tp_session_delete,
1674 };
1675
1676 #endif /* CONFIG_L2TP_V3 */
1677
pppol2tp_init(void)1678 static int __init pppol2tp_init(void)
1679 {
1680 int err;
1681
1682 err = register_pernet_device(&pppol2tp_net_ops);
1683 if (err)
1684 goto out;
1685
1686 err = proto_register(&pppol2tp_sk_proto, 0);
1687 if (err)
1688 goto out_unregister_pppol2tp_pernet;
1689
1690 err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1691 if (err)
1692 goto out_unregister_pppol2tp_proto;
1693
1694 #ifdef CONFIG_L2TP_V3
1695 err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1696 if (err)
1697 goto out_unregister_pppox;
1698 #endif
1699
1700 pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1701
1702 out:
1703 return err;
1704
1705 #ifdef CONFIG_L2TP_V3
1706 out_unregister_pppox:
1707 unregister_pppox_proto(PX_PROTO_OL2TP);
1708 #endif
1709 out_unregister_pppol2tp_proto:
1710 proto_unregister(&pppol2tp_sk_proto);
1711 out_unregister_pppol2tp_pernet:
1712 unregister_pernet_device(&pppol2tp_net_ops);
1713 goto out;
1714 }
1715
pppol2tp_exit(void)1716 static void __exit pppol2tp_exit(void)
1717 {
1718 #ifdef CONFIG_L2TP_V3
1719 l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1720 #endif
1721 unregister_pppox_proto(PX_PROTO_OL2TP);
1722 proto_unregister(&pppol2tp_sk_proto);
1723 unregister_pernet_device(&pppol2tp_net_ops);
1724 }
1725
1726 module_init(pppol2tp_init);
1727 module_exit(pppol2tp_exit);
1728
1729 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1730 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1731 MODULE_LICENSE("GPL");
1732 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1733 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OL2TP);
1734 MODULE_ALIAS_L2TP_PWTYPE(7);
1735