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 };
123
124 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
125
126 static const struct ppp_channel_ops pppol2tp_chan_ops = {
127 .start_xmit = pppol2tp_xmit,
128 };
129
130 static const struct proto_ops pppol2tp_ops;
131
132 /* Retrieves the pppol2tp socket associated to a session. */
pppol2tp_session_get_sock(struct l2tp_session * session)133 static struct sock *pppol2tp_session_get_sock(struct l2tp_session *session)
134 {
135 struct pppol2tp_session *ps = l2tp_session_priv(session);
136
137 return rcu_dereference(ps->sk);
138 }
139
140 /* Helpers to obtain tunnel/session contexts from sockets.
141 */
pppol2tp_sock_to_session(struct sock * sk)142 static struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
143 {
144 struct l2tp_session *session;
145
146 if (!sk)
147 return NULL;
148
149 rcu_read_lock();
150 session = rcu_dereference_sk_user_data(sk);
151 if (session && refcount_inc_not_zero(&session->ref_count)) {
152 rcu_read_unlock();
153 WARN_ON_ONCE(session->magic != L2TP_SESSION_MAGIC);
154 return session;
155 }
156 rcu_read_unlock();
157
158 return NULL;
159 }
160
161 /*****************************************************************************
162 * Receive data handling
163 *****************************************************************************/
164
165 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
166 */
pppol2tp_recvmsg(struct socket * sock,struct msghdr * msg,size_t len,int flags)167 static int pppol2tp_recvmsg(struct socket *sock, struct msghdr *msg,
168 size_t len, int flags)
169 {
170 int err;
171 struct sk_buff *skb;
172 struct sock *sk = sock->sk;
173
174 err = -EIO;
175 if (sk->sk_state & PPPOX_BOUND)
176 goto end;
177
178 err = 0;
179 skb = skb_recv_datagram(sk, flags, &err);
180 if (!skb)
181 goto end;
182
183 if (len > skb->len)
184 len = skb->len;
185 else if (len < skb->len)
186 msg->msg_flags |= MSG_TRUNC;
187
188 err = skb_copy_datagram_msg(skb, 0, msg, len);
189 if (likely(err == 0))
190 err = len;
191
192 kfree_skb(skb);
193 end:
194 return err;
195 }
196
pppol2tp_recv(struct l2tp_session * session,struct sk_buff * skb,int data_len)197 static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
198 {
199 struct sock *sk;
200
201 /* If the socket is bound, send it in to PPP's input queue. Otherwise
202 * queue it on the session socket.
203 */
204 rcu_read_lock();
205 sk = pppol2tp_session_get_sock(session);
206 if (!sk)
207 goto no_sock;
208
209 /* If the first two bytes are 0xFF03, consider that it is the PPP's
210 * Address and Control fields and skip them. The L2TP module has always
211 * worked this way, although, in theory, the use of these fields should
212 * be negotiated and handled at the PPP layer. These fields are
213 * constant: 0xFF is the All-Stations Address and 0x03 the Unnumbered
214 * Information command with Poll/Final bit set to zero (RFC 1662).
215 */
216 if (pskb_may_pull(skb, 2) && skb->data[0] == PPP_ALLSTATIONS &&
217 skb->data[1] == PPP_UI)
218 skb_pull(skb, 2);
219
220 if (sk->sk_state & PPPOX_BOUND) {
221 struct pppox_sock *po;
222
223 po = pppox_sk(sk);
224 ppp_input(&po->chan, skb);
225 } else {
226 if (sock_queue_rcv_skb(sk, skb) < 0) {
227 atomic_long_inc(&session->stats.rx_errors);
228 kfree_skb(skb);
229 }
230 }
231 rcu_read_unlock();
232
233 return;
234
235 no_sock:
236 rcu_read_unlock();
237 pr_warn_ratelimited("%s: no socket in recv\n", session->name);
238 kfree_skb(skb);
239 }
240
241 /************************************************************************
242 * Transmit handling
243 ***********************************************************************/
244
245 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket. We come here
246 * when a user application does a sendmsg() on the session socket. L2TP and
247 * PPP headers must be inserted into the user's data.
248 */
pppol2tp_sendmsg(struct socket * sock,struct msghdr * m,size_t total_len)249 static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
250 size_t total_len)
251 {
252 struct sock *sk = sock->sk;
253 struct sk_buff *skb;
254 int error;
255 struct l2tp_session *session;
256 struct l2tp_tunnel *tunnel;
257 int uhlen;
258
259 error = -ENOTCONN;
260 if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
261 goto error;
262
263 /* Get session and tunnel contexts */
264 error = -EBADF;
265 session = pppol2tp_sock_to_session(sk);
266 if (!session)
267 goto error;
268
269 tunnel = session->tunnel;
270
271 uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
272
273 /* Allocate a socket buffer */
274 error = -ENOMEM;
275 skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
276 uhlen + session->hdr_len +
277 2 + total_len, /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
278 0, GFP_KERNEL);
279 if (!skb)
280 goto error_put_sess;
281
282 /* Reserve space for headers. */
283 skb_reserve(skb, NET_SKB_PAD);
284 skb_reset_network_header(skb);
285 skb_reserve(skb, sizeof(struct iphdr));
286 skb_reset_transport_header(skb);
287 skb_reserve(skb, uhlen);
288
289 /* Add PPP header */
290 skb->data[0] = PPP_ALLSTATIONS;
291 skb->data[1] = PPP_UI;
292 skb_put(skb, 2);
293
294 /* Copy user data into skb */
295 error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
296 if (error < 0) {
297 kfree_skb(skb);
298 goto error_put_sess;
299 }
300
301 local_bh_disable();
302 l2tp_xmit_skb(session, skb);
303 local_bh_enable();
304
305 l2tp_session_put(session);
306
307 return total_len;
308
309 error_put_sess:
310 l2tp_session_put(session);
311 error:
312 return error;
313 }
314
315 /* Transmit function called by generic PPP driver. Sends PPP frame
316 * over PPPoL2TP socket.
317 *
318 * This is almost the same as pppol2tp_sendmsg(), but rather than
319 * being called with a msghdr from userspace, it is called with a skb
320 * from the kernel.
321 *
322 * The supplied skb from ppp doesn't have enough headroom for the
323 * insertion of L2TP, UDP and IP headers so we need to allocate more
324 * headroom in the skb. This will create a cloned skb. But we must be
325 * careful in the error case because the caller will expect to free
326 * the skb it supplied, not our cloned skb. So we take care to always
327 * leave the original skb unfreed if we return an error.
328 */
pppol2tp_xmit(struct ppp_channel * chan,struct sk_buff * skb)329 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
330 {
331 struct sock *sk = (struct sock *)chan->private;
332 struct l2tp_session *session;
333 struct l2tp_tunnel *tunnel;
334 int uhlen, headroom;
335
336 if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
337 goto abort;
338
339 /* Get session and tunnel contexts from the socket */
340 session = pppol2tp_sock_to_session(sk);
341 if (!session)
342 goto abort;
343
344 tunnel = session->tunnel;
345
346 uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
347 headroom = NET_SKB_PAD +
348 sizeof(struct iphdr) + /* IP header */
349 uhlen + /* UDP header (if L2TP_ENCAPTYPE_UDP) */
350 session->hdr_len + /* L2TP header */
351 2; /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
352 if (skb_cow_head(skb, headroom))
353 goto abort_put_sess;
354
355 /* Setup PPP header */
356 __skb_push(skb, 2);
357 skb->data[0] = PPP_ALLSTATIONS;
358 skb->data[1] = PPP_UI;
359
360 local_bh_disable();
361 l2tp_xmit_skb(session, skb);
362 local_bh_enable();
363
364 l2tp_session_put(session);
365
366 return 1;
367
368 abort_put_sess:
369 l2tp_session_put(session);
370 abort:
371 /* Free the original skb */
372 kfree_skb(skb);
373 return 1;
374 }
375
376 /*****************************************************************************
377 * Session (and tunnel control) socket create/destroy.
378 *****************************************************************************/
379
380 /* Really kill the session socket. (Called from sock_put() if
381 * refcnt == 0.)
382 */
pppol2tp_session_destruct(struct sock * sk)383 static void pppol2tp_session_destruct(struct sock *sk)
384 {
385 skb_queue_purge(&sk->sk_receive_queue);
386 skb_queue_purge(&sk->sk_write_queue);
387 }
388
pppol2tp_session_close(struct l2tp_session * session)389 static void pppol2tp_session_close(struct l2tp_session *session)
390 {
391 struct pppol2tp_session *ps;
392
393 ps = l2tp_session_priv(session);
394 mutex_lock(&ps->sk_lock);
395 ps->__sk = rcu_dereference_protected(ps->sk,
396 lockdep_is_held(&ps->sk_lock));
397 RCU_INIT_POINTER(ps->sk, NULL);
398 mutex_unlock(&ps->sk_lock);
399 if (ps->__sk) {
400 /* detach socket */
401 rcu_assign_sk_user_data(ps->__sk, NULL);
402 sock_put(ps->__sk);
403
404 /* drop ref taken when we referenced socket via sk_user_data */
405 l2tp_session_put(session);
406 }
407 }
408
409 /* Called when the PPPoX socket (session) is closed.
410 */
pppol2tp_release(struct socket * sock)411 static int pppol2tp_release(struct socket *sock)
412 {
413 struct sock *sk = sock->sk;
414 struct l2tp_session *session;
415 int error;
416
417 if (!sk)
418 return 0;
419
420 error = -EBADF;
421 lock_sock(sk);
422 if (sock_flag(sk, SOCK_DEAD) != 0)
423 goto error;
424
425 pppox_unbind_sock(sk);
426
427 /* Signal the death of the socket. */
428 sk->sk_state = PPPOX_DEAD;
429 sock_orphan(sk);
430 sock->sk = NULL;
431
432 session = pppol2tp_sock_to_session(sk);
433 if (session) {
434 l2tp_session_delete(session);
435 /* drop ref taken by pppol2tp_sock_to_session */
436 l2tp_session_put(session);
437 }
438
439 release_sock(sk);
440
441 sock_put(sk);
442
443 return 0;
444
445 error:
446 release_sock(sk);
447 return error;
448 }
449
450 static struct proto pppol2tp_sk_proto = {
451 .name = "PPPOL2TP",
452 .owner = THIS_MODULE,
453 .obj_size = sizeof(struct pppox_sock),
454 };
455
pppol2tp_backlog_recv(struct sock * sk,struct sk_buff * skb)456 static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
457 {
458 int rc;
459
460 rc = l2tp_udp_encap_recv(sk, skb);
461 if (rc)
462 kfree_skb(skb);
463
464 return NET_RX_SUCCESS;
465 }
466
467 /* socket() handler. Initialize a new struct sock.
468 */
pppol2tp_create(struct net * net,struct socket * sock,int kern)469 static int pppol2tp_create(struct net *net, struct socket *sock, int kern)
470 {
471 int error = -ENOMEM;
472 struct sock *sk;
473
474 sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto, kern);
475 if (!sk)
476 goto out;
477
478 sock_init_data(sock, sk);
479 sock_set_flag(sk, SOCK_RCU_FREE);
480
481 sock->state = SS_UNCONNECTED;
482 sock->ops = &pppol2tp_ops;
483
484 sk->sk_backlog_rcv = pppol2tp_backlog_recv;
485 sk->sk_protocol = PX_PROTO_OL2TP;
486 sk->sk_family = PF_PPPOX;
487 sk->sk_state = PPPOX_NONE;
488 sk->sk_type = SOCK_STREAM;
489 sk->sk_destruct = pppol2tp_session_destruct;
490
491 error = 0;
492
493 out:
494 return error;
495 }
496
pppol2tp_show(struct seq_file * m,void * arg)497 static void pppol2tp_show(struct seq_file *m, void *arg)
498 {
499 struct l2tp_session *session = arg;
500 struct sock *sk;
501
502 rcu_read_lock();
503 sk = pppol2tp_session_get_sock(session);
504 if (sk) {
505 struct pppox_sock *po = pppox_sk(sk);
506
507 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
508 }
509 rcu_read_unlock();
510 }
511
pppol2tp_session_init(struct l2tp_session * session)512 static void pppol2tp_session_init(struct l2tp_session *session)
513 {
514 struct pppol2tp_session *ps;
515
516 session->recv_skb = pppol2tp_recv;
517 session->session_close = pppol2tp_session_close;
518 if (IS_ENABLED(CONFIG_L2TP_DEBUGFS))
519 session->show = pppol2tp_show;
520
521 ps = l2tp_session_priv(session);
522 mutex_init(&ps->sk_lock);
523 ps->owner = current->pid;
524 }
525
526 struct l2tp_connect_info {
527 u8 version;
528 int fd;
529 u32 tunnel_id;
530 u32 peer_tunnel_id;
531 u32 session_id;
532 u32 peer_session_id;
533 };
534
pppol2tp_sockaddr_get_info(const void * sa,int sa_len,struct l2tp_connect_info * info)535 static int pppol2tp_sockaddr_get_info(const void *sa, int sa_len,
536 struct l2tp_connect_info *info)
537 {
538 switch (sa_len) {
539 case sizeof(struct sockaddr_pppol2tp):
540 {
541 const struct sockaddr_pppol2tp *sa_v2in4 = sa;
542
543 if (sa_v2in4->sa_protocol != PX_PROTO_OL2TP)
544 return -EINVAL;
545
546 info->version = 2;
547 info->fd = sa_v2in4->pppol2tp.fd;
548 info->tunnel_id = sa_v2in4->pppol2tp.s_tunnel;
549 info->peer_tunnel_id = sa_v2in4->pppol2tp.d_tunnel;
550 info->session_id = sa_v2in4->pppol2tp.s_session;
551 info->peer_session_id = sa_v2in4->pppol2tp.d_session;
552
553 break;
554 }
555 case sizeof(struct sockaddr_pppol2tpv3):
556 {
557 const struct sockaddr_pppol2tpv3 *sa_v3in4 = sa;
558
559 if (sa_v3in4->sa_protocol != PX_PROTO_OL2TP)
560 return -EINVAL;
561
562 info->version = 3;
563 info->fd = sa_v3in4->pppol2tp.fd;
564 info->tunnel_id = sa_v3in4->pppol2tp.s_tunnel;
565 info->peer_tunnel_id = sa_v3in4->pppol2tp.d_tunnel;
566 info->session_id = sa_v3in4->pppol2tp.s_session;
567 info->peer_session_id = sa_v3in4->pppol2tp.d_session;
568
569 break;
570 }
571 case sizeof(struct sockaddr_pppol2tpin6):
572 {
573 const struct sockaddr_pppol2tpin6 *sa_v2in6 = sa;
574
575 if (sa_v2in6->sa_protocol != PX_PROTO_OL2TP)
576 return -EINVAL;
577
578 info->version = 2;
579 info->fd = sa_v2in6->pppol2tp.fd;
580 info->tunnel_id = sa_v2in6->pppol2tp.s_tunnel;
581 info->peer_tunnel_id = sa_v2in6->pppol2tp.d_tunnel;
582 info->session_id = sa_v2in6->pppol2tp.s_session;
583 info->peer_session_id = sa_v2in6->pppol2tp.d_session;
584
585 break;
586 }
587 case sizeof(struct sockaddr_pppol2tpv3in6):
588 {
589 const struct sockaddr_pppol2tpv3in6 *sa_v3in6 = sa;
590
591 if (sa_v3in6->sa_protocol != PX_PROTO_OL2TP)
592 return -EINVAL;
593
594 info->version = 3;
595 info->fd = sa_v3in6->pppol2tp.fd;
596 info->tunnel_id = sa_v3in6->pppol2tp.s_tunnel;
597 info->peer_tunnel_id = sa_v3in6->pppol2tp.d_tunnel;
598 info->session_id = sa_v3in6->pppol2tp.s_session;
599 info->peer_session_id = sa_v3in6->pppol2tp.d_session;
600
601 break;
602 }
603 default:
604 return -EINVAL;
605 }
606
607 return 0;
608 }
609
610 /* Rough estimation of the maximum payload size a tunnel can transmit without
611 * fragmenting at the lower IP layer. Assumes L2TPv2 with sequence
612 * numbers and no IP option. Not quite accurate, but the result is mostly
613 * unused anyway.
614 */
pppol2tp_tunnel_mtu(const struct l2tp_tunnel * tunnel)615 static int pppol2tp_tunnel_mtu(const struct l2tp_tunnel *tunnel)
616 {
617 int mtu;
618
619 mtu = l2tp_tunnel_dst_mtu(tunnel);
620 if (mtu <= PPPOL2TP_HEADER_OVERHEAD)
621 return 1500 - PPPOL2TP_HEADER_OVERHEAD;
622
623 return mtu - PPPOL2TP_HEADER_OVERHEAD;
624 }
625
pppol2tp_tunnel_get(struct net * net,const struct l2tp_connect_info * info,bool * new_tunnel)626 static struct l2tp_tunnel *pppol2tp_tunnel_get(struct net *net,
627 const struct l2tp_connect_info *info,
628 bool *new_tunnel)
629 {
630 struct l2tp_tunnel *tunnel;
631 int error;
632
633 *new_tunnel = false;
634
635 tunnel = l2tp_tunnel_get(net, info->tunnel_id);
636
637 /* Special case: create tunnel context if session_id and
638 * peer_session_id is 0. Otherwise look up tunnel using supplied
639 * tunnel id.
640 */
641 if (!info->session_id && !info->peer_session_id) {
642 if (!tunnel) {
643 struct l2tp_tunnel_cfg tcfg = {
644 .encap = L2TP_ENCAPTYPE_UDP,
645 };
646
647 /* Prevent l2tp_tunnel_register() from trying to set up
648 * a kernel socket.
649 */
650 if (info->fd < 0)
651 return ERR_PTR(-EBADF);
652
653 error = l2tp_tunnel_create(info->fd,
654 info->version,
655 info->tunnel_id,
656 info->peer_tunnel_id, &tcfg,
657 &tunnel);
658 if (error < 0)
659 return ERR_PTR(error);
660
661 refcount_inc(&tunnel->ref_count);
662 error = l2tp_tunnel_register(tunnel, net, &tcfg);
663 if (error < 0) {
664 kfree(tunnel);
665 return ERR_PTR(error);
666 }
667
668 *new_tunnel = true;
669 }
670 } else {
671 /* Error if we can't find the tunnel */
672 if (!tunnel)
673 return ERR_PTR(-ENOENT);
674
675 /* Error if socket is not prepped */
676 if (!tunnel->sock) {
677 l2tp_tunnel_put(tunnel);
678 return ERR_PTR(-ENOENT);
679 }
680 }
681
682 return tunnel;
683 }
684
685 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
686 */
pppol2tp_connect(struct socket * sock,struct sockaddr_unsized * uservaddr,int sockaddr_len,int flags)687 static int pppol2tp_connect(struct socket *sock, struct sockaddr_unsized *uservaddr,
688 int sockaddr_len, int flags)
689 {
690 struct sock *sk = sock->sk;
691 struct pppox_sock *po = pppox_sk(sk);
692 struct l2tp_session *session = NULL;
693 struct l2tp_connect_info info;
694 struct l2tp_tunnel *tunnel;
695 struct pppol2tp_session *ps;
696 struct l2tp_session_cfg cfg = { 0, };
697 bool drop_refcnt = false;
698 bool new_session = false;
699 bool new_tunnel = false;
700 int error;
701
702 error = pppol2tp_sockaddr_get_info(uservaddr, sockaddr_len, &info);
703 if (error < 0)
704 return error;
705
706 /* Don't bind if tunnel_id is 0 */
707 if (!info.tunnel_id)
708 return -EINVAL;
709
710 tunnel = pppol2tp_tunnel_get(sock_net(sk), &info, &new_tunnel);
711 if (IS_ERR(tunnel))
712 return PTR_ERR(tunnel);
713
714 lock_sock(sk);
715
716 /* Check for already bound sockets */
717 error = -EBUSY;
718 if (sk->sk_state & PPPOX_CONNECTED)
719 goto end;
720
721 /* We don't supporting rebinding anyway */
722 error = -EALREADY;
723 if (sk->sk_user_data)
724 goto end; /* socket is already attached */
725
726 if (tunnel->peer_tunnel_id == 0)
727 tunnel->peer_tunnel_id = info.peer_tunnel_id;
728
729 session = l2tp_session_get(sock_net(sk), tunnel->sock, tunnel->version,
730 info.tunnel_id, info.session_id);
731 if (session) {
732 drop_refcnt = true;
733
734 if (session->pwtype != L2TP_PWTYPE_PPP) {
735 error = -EPROTOTYPE;
736 goto end;
737 }
738
739 ps = l2tp_session_priv(session);
740
741 /* Using a pre-existing session is fine as long as it hasn't
742 * been connected yet.
743 */
744 mutex_lock(&ps->sk_lock);
745 if (rcu_dereference_protected(ps->sk,
746 lockdep_is_held(&ps->sk_lock)) ||
747 ps->__sk) {
748 mutex_unlock(&ps->sk_lock);
749 error = -EEXIST;
750 goto end;
751 }
752 } else {
753 cfg.pw_type = L2TP_PWTYPE_PPP;
754
755 session = l2tp_session_create(sizeof(struct pppol2tp_session),
756 tunnel, info.session_id,
757 info.peer_session_id, &cfg);
758 if (IS_ERR(session)) {
759 error = PTR_ERR(session);
760 goto end;
761 }
762
763 drop_refcnt = true;
764
765 pppol2tp_session_init(session);
766 ps = l2tp_session_priv(session);
767 refcount_inc(&session->ref_count);
768
769 mutex_lock(&ps->sk_lock);
770 error = l2tp_session_register(session, tunnel);
771 if (error < 0) {
772 mutex_unlock(&ps->sk_lock);
773 l2tp_session_put(session);
774 goto end;
775 }
776
777 new_session = true;
778 }
779
780 /* Special case: if source & dest session_id == 0x0000, this
781 * socket is being created to manage the tunnel. Just set up
782 * the internal context for use by ioctl() and sockopt()
783 * handlers.
784 */
785 if (session->session_id == 0 && session->peer_session_id == 0) {
786 error = 0;
787 goto out_no_ppp;
788 }
789
790 /* Reserve enough headroom for the L2TP header with sequence numbers,
791 * which is the largest possible. This is used by the PPP layer to set
792 * the net device's hard_header_len at registration, which must be
793 * sufficient regardless of whether sequence numbers are enabled later.
794 */
795 po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_SEQ;
796
797 po->chan.private = sk;
798 po->chan.ops = &pppol2tp_chan_ops;
799 po->chan.mtu = pppol2tp_tunnel_mtu(tunnel);
800 po->chan.direct_xmit = true;
801
802 error = ppp_register_net_channel(sock_net(sk), &po->chan);
803 if (error) {
804 mutex_unlock(&ps->sk_lock);
805 goto end;
806 }
807
808 out_no_ppp:
809 /* This is how we get the session context from the socket. */
810 sock_hold(sk);
811 rcu_assign_sk_user_data(sk, session);
812 rcu_assign_pointer(ps->sk, sk);
813 mutex_unlock(&ps->sk_lock);
814
815 /* Keep the reference we've grabbed on the session: sk doesn't expect
816 * the session to disappear. pppol2tp_session_close() is responsible
817 * for dropping it.
818 */
819 drop_refcnt = false;
820
821 sk->sk_state = PPPOX_CONNECTED;
822
823 end:
824 if (error) {
825 if (new_session)
826 l2tp_session_delete(session);
827 if (new_tunnel)
828 l2tp_tunnel_delete(tunnel);
829 }
830 if (drop_refcnt)
831 l2tp_session_put(session);
832 l2tp_tunnel_put(tunnel);
833 release_sock(sk);
834
835 return error;
836 }
837
838 #ifdef CONFIG_L2TP_V3
839
840 /* 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)841 static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
842 u32 session_id, u32 peer_session_id,
843 struct l2tp_session_cfg *cfg)
844 {
845 int error;
846 struct l2tp_session *session;
847
848 /* Error if tunnel socket is not prepped */
849 if (!tunnel->sock) {
850 error = -ENOENT;
851 goto err;
852 }
853
854 /* Allocate and initialize a new session context. */
855 session = l2tp_session_create(sizeof(struct pppol2tp_session),
856 tunnel, session_id,
857 peer_session_id, cfg);
858 if (IS_ERR(session)) {
859 error = PTR_ERR(session);
860 goto err;
861 }
862
863 pppol2tp_session_init(session);
864
865 error = l2tp_session_register(session, tunnel);
866 if (error < 0)
867 goto err_sess;
868
869 return 0;
870
871 err_sess:
872 l2tp_session_put(session);
873 err:
874 return error;
875 }
876
877 #endif /* CONFIG_L2TP_V3 */
878
879 /* getname() support.
880 */
pppol2tp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)881 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
882 int peer)
883 {
884 int len = 0;
885 int error = 0;
886 struct l2tp_session *session;
887 struct l2tp_tunnel *tunnel;
888 struct sock *sk = sock->sk;
889 struct inet_sock *inet;
890 struct pppol2tp_session *pls;
891
892 error = -ENOTCONN;
893 if (!sk)
894 goto end;
895 if (!(sk->sk_state & PPPOX_CONNECTED))
896 goto end;
897
898 error = -EBADF;
899 session = pppol2tp_sock_to_session(sk);
900 if (!session)
901 goto end;
902
903 pls = l2tp_session_priv(session);
904 tunnel = session->tunnel;
905
906 inet = inet_sk(tunnel->sock);
907 if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET) {
908 struct sockaddr_pppol2tp sp;
909
910 len = sizeof(sp);
911 memset(&sp, 0, len);
912 sp.sa_family = AF_PPPOX;
913 sp.sa_protocol = PX_PROTO_OL2TP;
914 sp.pppol2tp.fd = tunnel->fd;
915 sp.pppol2tp.pid = pls->owner;
916 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
917 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
918 sp.pppol2tp.s_session = session->session_id;
919 sp.pppol2tp.d_session = session->peer_session_id;
920 sp.pppol2tp.addr.sin_family = AF_INET;
921 sp.pppol2tp.addr.sin_port = inet->inet_dport;
922 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
923 memcpy(uaddr, &sp, len);
924 #if IS_ENABLED(CONFIG_IPV6)
925 } else if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET6) {
926 struct sockaddr_pppol2tpin6 sp;
927
928 len = sizeof(sp);
929 memset(&sp, 0, len);
930 sp.sa_family = AF_PPPOX;
931 sp.sa_protocol = PX_PROTO_OL2TP;
932 sp.pppol2tp.fd = tunnel->fd;
933 sp.pppol2tp.pid = pls->owner;
934 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
935 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
936 sp.pppol2tp.s_session = session->session_id;
937 sp.pppol2tp.d_session = session->peer_session_id;
938 sp.pppol2tp.addr.sin6_family = AF_INET6;
939 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
940 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
941 sizeof(tunnel->sock->sk_v6_daddr));
942 memcpy(uaddr, &sp, len);
943 } else if (tunnel->version == 3 && tunnel->sock->sk_family == AF_INET6) {
944 struct sockaddr_pppol2tpv3in6 sp;
945
946 len = sizeof(sp);
947 memset(&sp, 0, len);
948 sp.sa_family = AF_PPPOX;
949 sp.sa_protocol = PX_PROTO_OL2TP;
950 sp.pppol2tp.fd = tunnel->fd;
951 sp.pppol2tp.pid = pls->owner;
952 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
953 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
954 sp.pppol2tp.s_session = session->session_id;
955 sp.pppol2tp.d_session = session->peer_session_id;
956 sp.pppol2tp.addr.sin6_family = AF_INET6;
957 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
958 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
959 sizeof(tunnel->sock->sk_v6_daddr));
960 memcpy(uaddr, &sp, len);
961 #endif
962 } else if (tunnel->version == 3) {
963 struct sockaddr_pppol2tpv3 sp;
964
965 len = sizeof(sp);
966 memset(&sp, 0, len);
967 sp.sa_family = AF_PPPOX;
968 sp.sa_protocol = PX_PROTO_OL2TP;
969 sp.pppol2tp.fd = tunnel->fd;
970 sp.pppol2tp.pid = pls->owner;
971 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
972 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
973 sp.pppol2tp.s_session = session->session_id;
974 sp.pppol2tp.d_session = session->peer_session_id;
975 sp.pppol2tp.addr.sin_family = AF_INET;
976 sp.pppol2tp.addr.sin_port = inet->inet_dport;
977 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
978 memcpy(uaddr, &sp, len);
979 }
980
981 error = len;
982
983 l2tp_session_put(session);
984 end:
985 return error;
986 }
987
988 /****************************************************************************
989 * ioctl() handlers.
990 *
991 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
992 * sockets. However, in order to control kernel tunnel features, we allow
993 * userspace to create a special "tunnel" PPPoX socket which is used for
994 * control only. Tunnel PPPoX sockets have session_id == 0 and simply allow
995 * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
996 * calls.
997 ****************************************************************************/
998
pppol2tp_copy_stats(struct pppol2tp_ioc_stats * dest,const struct l2tp_stats * stats)999 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
1000 const struct l2tp_stats *stats)
1001 {
1002 memset(dest, 0, sizeof(*dest));
1003
1004 dest->tx_packets = atomic_long_read(&stats->tx_packets);
1005 dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
1006 dest->tx_errors = atomic_long_read(&stats->tx_errors);
1007 dest->rx_packets = atomic_long_read(&stats->rx_packets);
1008 dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
1009 dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
1010 dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
1011 dest->rx_errors = atomic_long_read(&stats->rx_errors);
1012 }
1013
pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats * stats,struct l2tp_tunnel * tunnel)1014 static int pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats *stats,
1015 struct l2tp_tunnel *tunnel)
1016 {
1017 struct l2tp_session *session;
1018
1019 if (!stats->session_id) {
1020 pppol2tp_copy_stats(stats, &tunnel->stats);
1021 return 0;
1022 }
1023
1024 /* If session_id is set, search the corresponding session in the
1025 * context of this tunnel and record the session's statistics.
1026 */
1027 session = l2tp_session_get(tunnel->l2tp_net, tunnel->sock, tunnel->version,
1028 tunnel->tunnel_id, stats->session_id);
1029 if (!session)
1030 return -EBADR;
1031
1032 if (session->pwtype != L2TP_PWTYPE_PPP) {
1033 l2tp_session_put(session);
1034 return -EBADR;
1035 }
1036
1037 pppol2tp_copy_stats(stats, &session->stats);
1038 l2tp_session_put(session);
1039
1040 return 0;
1041 }
1042
pppol2tp_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)1043 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1044 unsigned long arg)
1045 {
1046 struct pppol2tp_ioc_stats stats;
1047 struct l2tp_session *session;
1048 int err = 0;
1049
1050 session = pppol2tp_sock_to_session(sock->sk);
1051
1052 /* Validate session presence and magic integrity ONLY for commands
1053 * that belong to L2TP and require a valid session.
1054 */
1055 switch (cmd) {
1056 case PPPIOCGMRU:
1057 case PPPIOCGFLAGS:
1058 case PPPIOCSMRU:
1059 case PPPIOCSFLAGS:
1060 case PPPIOCGL2TPSTATS:
1061 if (!session)
1062 return -ENOTCONN;
1063
1064 if (session->magic != L2TP_SESSION_MAGIC) {
1065 l2tp_session_put(session);
1066 return -EBADF;
1067 }
1068 break;
1069 default:
1070 break;
1071 }
1072
1073 switch (cmd) {
1074 case PPPIOCGMRU:
1075 case PPPIOCGFLAGS:
1076 /* Not defined for tunnels */
1077 if (!session->session_id && !session->peer_session_id) {
1078 err = -ENOSYS;
1079 break;
1080 }
1081
1082 if (put_user(0, (int __user *)arg)) {
1083 err = -EFAULT;
1084 break;
1085 }
1086 break;
1087
1088 case PPPIOCSMRU:
1089 case PPPIOCSFLAGS:
1090 /* Not defined for tunnels */
1091 if (!session->session_id && !session->peer_session_id) {
1092 err = -ENOSYS;
1093 break;
1094 }
1095
1096 if (!access_ok((int __user *)arg, sizeof(int))) {
1097 err = -EFAULT;
1098 break;
1099 }
1100 break;
1101
1102 case PPPIOCGL2TPSTATS:
1103 /* Session 0 represents the parent tunnel */
1104 if (!session->session_id && !session->peer_session_id) {
1105 u32 session_id;
1106
1107 if (copy_from_user(&stats, (void __user *)arg,
1108 sizeof(stats))) {
1109 err = -EFAULT;
1110 break;
1111 }
1112
1113 session_id = stats.session_id;
1114 err = pppol2tp_tunnel_copy_stats(&stats,
1115 session->tunnel);
1116 if (err < 0)
1117 break;
1118
1119 stats.session_id = session_id;
1120 } else {
1121 pppol2tp_copy_stats(&stats, &session->stats);
1122 stats.session_id = session->session_id;
1123 }
1124 stats.tunnel_id = session->tunnel->tunnel_id;
1125 stats.using_ipsec = l2tp_tunnel_uses_xfrm(session->tunnel);
1126
1127 if (copy_to_user((void __user *)arg, &stats, sizeof(stats))) {
1128 err = -EFAULT;
1129 break;
1130 }
1131 break;
1132
1133 default:
1134 err = -ENOIOCTLCMD;
1135 break;
1136 }
1137
1138 if (session)
1139 l2tp_session_put(session);
1140
1141 return err;
1142 }
1143
1144 /*****************************************************************************
1145 * setsockopt() / getsockopt() support.
1146 *
1147 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1148 * sockets. In order to control kernel tunnel features, we allow userspace to
1149 * create a special "tunnel" PPPoX socket which is used for control only.
1150 * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1151 * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1152 *****************************************************************************/
1153
1154 /* Tunnel setsockopt() helper.
1155 */
pppol2tp_tunnel_setsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int val)1156 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1157 struct l2tp_tunnel *tunnel,
1158 int optname, int val)
1159 {
1160 int err = 0;
1161
1162 switch (optname) {
1163 case PPPOL2TP_SO_DEBUG:
1164 /* Tunnel debug flags option is deprecated */
1165 break;
1166
1167 default:
1168 err = -ENOPROTOOPT;
1169 break;
1170 }
1171
1172 return err;
1173 }
1174
1175 /* Session setsockopt helper.
1176 */
pppol2tp_session_setsockopt(struct sock * sk,struct l2tp_session * session,int optname,int val)1177 static int pppol2tp_session_setsockopt(struct sock *sk,
1178 struct l2tp_session *session,
1179 int optname, int val)
1180 {
1181 int err = 0;
1182
1183 switch (optname) {
1184 case PPPOL2TP_SO_RECVSEQ:
1185 if (val != 0 && val != 1) {
1186 err = -EINVAL;
1187 break;
1188 }
1189 session->recv_seq = !!val;
1190 break;
1191
1192 case PPPOL2TP_SO_SENDSEQ:
1193 if (val != 0 && val != 1) {
1194 err = -EINVAL;
1195 break;
1196 }
1197 session->send_seq = !!val;
1198 l2tp_session_set_header_len(session, session->tunnel->version,
1199 session->tunnel->encap);
1200 break;
1201
1202 case PPPOL2TP_SO_LNSMODE:
1203 if (val != 0 && val != 1) {
1204 err = -EINVAL;
1205 break;
1206 }
1207 session->lns_mode = !!val;
1208 break;
1209
1210 case PPPOL2TP_SO_DEBUG:
1211 /* Session debug flags option is deprecated */
1212 break;
1213
1214 case PPPOL2TP_SO_REORDERTO:
1215 session->reorder_timeout = msecs_to_jiffies(val);
1216 break;
1217
1218 default:
1219 err = -ENOPROTOOPT;
1220 break;
1221 }
1222
1223 return err;
1224 }
1225
1226 /* Main setsockopt() entry point.
1227 * Does API checks, then calls either the tunnel or session setsockopt
1228 * handler, according to whether the PPPoL2TP socket is a for a regular
1229 * session or the special tunnel type.
1230 */
pppol2tp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1231 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1232 sockptr_t optval, unsigned int optlen)
1233 {
1234 struct sock *sk = sock->sk;
1235 struct l2tp_session *session;
1236 struct l2tp_tunnel *tunnel;
1237 int val;
1238 int err;
1239
1240 if (level != SOL_PPPOL2TP)
1241 return -EINVAL;
1242
1243 if (optlen < sizeof(int))
1244 return -EINVAL;
1245
1246 if (copy_from_sockptr(&val, optval, sizeof(int)))
1247 return -EFAULT;
1248
1249 err = -ENOTCONN;
1250 if (!sk->sk_user_data)
1251 goto end;
1252
1253 /* Get session context from the socket */
1254 err = -EBADF;
1255 session = pppol2tp_sock_to_session(sk);
1256 if (!session)
1257 goto end;
1258
1259 /* Special case: if session_id == 0x0000, treat as operation on tunnel
1260 */
1261 if (session->session_id == 0 && session->peer_session_id == 0) {
1262 tunnel = session->tunnel;
1263 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1264 } else {
1265 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1266 }
1267
1268 l2tp_session_put(session);
1269 end:
1270 return err;
1271 }
1272
1273 /* Tunnel getsockopt helper. Called with sock locked.
1274 */
pppol2tp_tunnel_getsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int * val)1275 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1276 struct l2tp_tunnel *tunnel,
1277 int optname, int *val)
1278 {
1279 int err = 0;
1280
1281 switch (optname) {
1282 case PPPOL2TP_SO_DEBUG:
1283 /* Tunnel debug flags option is deprecated */
1284 *val = 0;
1285 break;
1286
1287 default:
1288 err = -ENOPROTOOPT;
1289 break;
1290 }
1291
1292 return err;
1293 }
1294
1295 /* Session getsockopt helper. Called with sock locked.
1296 */
pppol2tp_session_getsockopt(struct sock * sk,struct l2tp_session * session,int optname,int * val)1297 static int pppol2tp_session_getsockopt(struct sock *sk,
1298 struct l2tp_session *session,
1299 int optname, int *val)
1300 {
1301 int err = 0;
1302
1303 switch (optname) {
1304 case PPPOL2TP_SO_RECVSEQ:
1305 *val = session->recv_seq;
1306 break;
1307
1308 case PPPOL2TP_SO_SENDSEQ:
1309 *val = session->send_seq;
1310 break;
1311
1312 case PPPOL2TP_SO_LNSMODE:
1313 *val = session->lns_mode;
1314 break;
1315
1316 case PPPOL2TP_SO_DEBUG:
1317 /* Session debug flags option is deprecated */
1318 *val = 0;
1319 break;
1320
1321 case PPPOL2TP_SO_REORDERTO:
1322 *val = (int)jiffies_to_msecs(session->reorder_timeout);
1323 break;
1324
1325 default:
1326 err = -ENOPROTOOPT;
1327 }
1328
1329 return err;
1330 }
1331
1332 /* Main getsockopt() entry point.
1333 * Does API checks, then calls either the tunnel or session getsockopt
1334 * handler, according to whether the PPPoX socket is a for a regular session
1335 * or the special tunnel type.
1336 */
pppol2tp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1337 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1338 char __user *optval, int __user *optlen)
1339 {
1340 struct sock *sk = sock->sk;
1341 struct l2tp_session *session;
1342 struct l2tp_tunnel *tunnel;
1343 int val, len;
1344 int err;
1345
1346 if (level != SOL_PPPOL2TP)
1347 return -EINVAL;
1348
1349 if (get_user(len, optlen))
1350 return -EFAULT;
1351
1352 if (len < 0)
1353 return -EINVAL;
1354
1355 len = min_t(unsigned int, len, sizeof(int));
1356
1357 err = -ENOTCONN;
1358 if (!sk->sk_user_data)
1359 goto end;
1360
1361 /* Get the session context */
1362 err = -EBADF;
1363 session = pppol2tp_sock_to_session(sk);
1364 if (!session)
1365 goto end;
1366
1367 /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1368 if (session->session_id == 0 && session->peer_session_id == 0) {
1369 tunnel = session->tunnel;
1370 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1371 if (err)
1372 goto end_put_sess;
1373 } else {
1374 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1375 if (err)
1376 goto end_put_sess;
1377 }
1378
1379 err = -EFAULT;
1380 if (put_user(len, optlen))
1381 goto end_put_sess;
1382
1383 if (copy_to_user((void __user *)optval, &val, len))
1384 goto end_put_sess;
1385
1386 err = 0;
1387
1388 end_put_sess:
1389 l2tp_session_put(session);
1390 end:
1391 return err;
1392 }
1393
1394 /*****************************************************************************
1395 * /proc filesystem for debug
1396 * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1397 * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1398 *****************************************************************************/
1399
1400 #ifdef CONFIG_PROC_FS
1401
1402 struct pppol2tp_seq_data {
1403 struct seq_net_private p;
1404 unsigned long tkey; /* lookup key of current tunnel */
1405 unsigned long skey; /* lookup key of current session */
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_put(pd->tunnel);
1415
1416 for (;;) {
1417 pd->tunnel = l2tp_tunnel_get_next(net, &pd->tkey);
1418 pd->tkey++;
1419
1420 /* Only accept L2TPv2 tunnels */
1421 if (!pd->tunnel || pd->tunnel->version == 2)
1422 return;
1423
1424 l2tp_tunnel_put(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_put(pd->session);
1433
1434 pd->session = l2tp_session_get_next(net, pd->tunnel->sock,
1435 pd->tunnel->version,
1436 pd->tunnel->tunnel_id, &pd->skey);
1437 pd->skey++;
1438
1439 if (!pd->session) {
1440 pd->skey = 0;
1441 pppol2tp_next_tunnel(net, pd);
1442 }
1443 }
1444
pppol2tp_seq_start(struct seq_file * m,loff_t * offs)1445 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1446 {
1447 struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1448 loff_t pos = *offs;
1449 struct net *net;
1450
1451 if (!pos)
1452 goto out;
1453
1454 if (WARN_ON(!m->private)) {
1455 pd = NULL;
1456 goto out;
1457 }
1458
1459 pd = m->private;
1460 net = seq_file_net(m);
1461
1462 if (!pd->tunnel)
1463 pppol2tp_next_tunnel(net, pd);
1464 else
1465 pppol2tp_next_session(net, pd);
1466
1467 /* NULL tunnel and session indicates end of list */
1468 if (!pd->tunnel && !pd->session)
1469 pd = NULL;
1470
1471 out:
1472 return pd;
1473 }
1474
pppol2tp_seq_next(struct seq_file * m,void * v,loff_t * pos)1475 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1476 {
1477 (*pos)++;
1478 return NULL;
1479 }
1480
pppol2tp_seq_stop(struct seq_file * p,void * v)1481 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1482 {
1483 struct pppol2tp_seq_data *pd = v;
1484
1485 if (!pd || pd == SEQ_START_TOKEN)
1486 return;
1487
1488 /* Drop reference taken by last invocation of pppol2tp_next_session()
1489 * or pppol2tp_next_tunnel().
1490 */
1491 if (pd->session) {
1492 l2tp_session_put(pd->session);
1493 pd->session = NULL;
1494 }
1495 if (pd->tunnel) {
1496 l2tp_tunnel_put(pd->tunnel);
1497 pd->tunnel = NULL;
1498 }
1499 }
1500
pppol2tp_seq_tunnel_show(struct seq_file * m,void * v)1501 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1502 {
1503 struct l2tp_tunnel *tunnel = v;
1504
1505 seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1506 tunnel->name,
1507 tunnel->sock ? 'Y' : 'N',
1508 refcount_read(&tunnel->ref_count) - 1);
1509 seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1510 0,
1511 atomic_long_read(&tunnel->stats.tx_packets),
1512 atomic_long_read(&tunnel->stats.tx_bytes),
1513 atomic_long_read(&tunnel->stats.tx_errors),
1514 atomic_long_read(&tunnel->stats.rx_packets),
1515 atomic_long_read(&tunnel->stats.rx_bytes),
1516 atomic_long_read(&tunnel->stats.rx_errors));
1517 }
1518
pppol2tp_seq_session_show(struct seq_file * m,void * v)1519 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1520 {
1521 struct l2tp_session *session = v;
1522 struct l2tp_tunnel *tunnel = session->tunnel;
1523 unsigned char state;
1524 char user_data_ok;
1525 struct sock *sk;
1526 u32 ip = 0;
1527 u16 port = 0;
1528
1529 if (tunnel->sock) {
1530 struct inet_sock *inet = inet_sk(tunnel->sock);
1531
1532 ip = ntohl(inet->inet_saddr);
1533 port = ntohs(inet->inet_sport);
1534 }
1535
1536 rcu_read_lock();
1537 sk = pppol2tp_session_get_sock(session);
1538 if (sk) {
1539 state = sk->sk_state;
1540 user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';
1541 } else {
1542 state = 0;
1543 user_data_ok = 'N';
1544 }
1545
1546 seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> %04X/%04X %d %c\n",
1547 session->name, ip, port,
1548 tunnel->tunnel_id,
1549 session->session_id,
1550 tunnel->peer_tunnel_id,
1551 session->peer_session_id,
1552 state, user_data_ok);
1553 seq_printf(m, " 0/0/%c/%c/%s %08x %u\n",
1554 session->recv_seq ? 'R' : '-',
1555 session->send_seq ? 'S' : '-',
1556 session->lns_mode ? "LNS" : "LAC",
1557 0,
1558 jiffies_to_msecs(session->reorder_timeout));
1559 seq_printf(m, " %u/%u %ld/%ld/%ld %ld/%ld/%ld\n",
1560 session->nr, session->ns,
1561 atomic_long_read(&session->stats.tx_packets),
1562 atomic_long_read(&session->stats.tx_bytes),
1563 atomic_long_read(&session->stats.tx_errors),
1564 atomic_long_read(&session->stats.rx_packets),
1565 atomic_long_read(&session->stats.rx_bytes),
1566 atomic_long_read(&session->stats.rx_errors));
1567
1568 if (sk) {
1569 struct pppox_sock *po = pppox_sk(sk);
1570
1571 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
1572 }
1573 rcu_read_unlock();
1574 }
1575
pppol2tp_seq_show(struct seq_file * m,void * v)1576 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1577 {
1578 struct pppol2tp_seq_data *pd = v;
1579
1580 /* display header on line 1 */
1581 if (v == SEQ_START_TOKEN) {
1582 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1583 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1584 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1585 seq_puts(m, " SESSION name, addr/port src-tid/sid dest-tid/sid state user-data-ok\n");
1586 seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1587 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1588 goto out;
1589 }
1590
1591 if (!pd->session)
1592 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1593 else
1594 pppol2tp_seq_session_show(m, pd->session);
1595
1596 out:
1597 return 0;
1598 }
1599
1600 static const struct seq_operations pppol2tp_seq_ops = {
1601 .start = pppol2tp_seq_start,
1602 .next = pppol2tp_seq_next,
1603 .stop = pppol2tp_seq_stop,
1604 .show = pppol2tp_seq_show,
1605 };
1606 #endif /* CONFIG_PROC_FS */
1607
1608 /*****************************************************************************
1609 * Network namespace
1610 *****************************************************************************/
1611
pppol2tp_init_net(struct net * net)1612 static __net_init int pppol2tp_init_net(struct net *net)
1613 {
1614 struct proc_dir_entry *pde;
1615 int err = 0;
1616
1617 pde = proc_create_net("pppol2tp", 0444, net->proc_net,
1618 &pppol2tp_seq_ops, sizeof(struct pppol2tp_seq_data));
1619 if (!pde) {
1620 err = -ENOMEM;
1621 goto out;
1622 }
1623
1624 out:
1625 return err;
1626 }
1627
pppol2tp_exit_net(struct net * net)1628 static __net_exit void pppol2tp_exit_net(struct net *net)
1629 {
1630 remove_proc_entry("pppol2tp", net->proc_net);
1631 }
1632
1633 static struct pernet_operations pppol2tp_net_ops = {
1634 .init = pppol2tp_init_net,
1635 .exit = pppol2tp_exit_net,
1636 };
1637
1638 /*****************************************************************************
1639 * Init and cleanup
1640 *****************************************************************************/
1641
1642 static const struct proto_ops pppol2tp_ops = {
1643 .family = AF_PPPOX,
1644 .owner = THIS_MODULE,
1645 .release = pppol2tp_release,
1646 .bind = sock_no_bind,
1647 .connect = pppol2tp_connect,
1648 .socketpair = sock_no_socketpair,
1649 .accept = sock_no_accept,
1650 .getname = pppol2tp_getname,
1651 .poll = datagram_poll,
1652 .listen = sock_no_listen,
1653 .shutdown = sock_no_shutdown,
1654 .setsockopt = pppol2tp_setsockopt,
1655 .getsockopt = pppol2tp_getsockopt,
1656 .sendmsg = pppol2tp_sendmsg,
1657 .recvmsg = pppol2tp_recvmsg,
1658 .mmap = sock_no_mmap,
1659 .ioctl = pppox_ioctl,
1660 #ifdef CONFIG_COMPAT
1661 .compat_ioctl = pppox_compat_ioctl,
1662 #endif
1663 };
1664
1665 static const struct pppox_proto pppol2tp_proto = {
1666 .create = pppol2tp_create,
1667 .ioctl = pppol2tp_ioctl,
1668 .owner = THIS_MODULE,
1669 };
1670
1671 #ifdef CONFIG_L2TP_V3
1672
1673 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1674 .session_create = pppol2tp_session_create,
1675 .session_delete = l2tp_session_delete,
1676 };
1677
1678 #endif /* CONFIG_L2TP_V3 */
1679
pppol2tp_init(void)1680 static int __init pppol2tp_init(void)
1681 {
1682 int err;
1683
1684 err = register_pernet_device(&pppol2tp_net_ops);
1685 if (err)
1686 goto out;
1687
1688 err = proto_register(&pppol2tp_sk_proto, 0);
1689 if (err)
1690 goto out_unregister_pppol2tp_pernet;
1691
1692 err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1693 if (err)
1694 goto out_unregister_pppol2tp_proto;
1695
1696 #ifdef CONFIG_L2TP_V3
1697 err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1698 if (err)
1699 goto out_unregister_pppox;
1700 #endif
1701
1702 pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1703
1704 out:
1705 return err;
1706
1707 #ifdef CONFIG_L2TP_V3
1708 out_unregister_pppox:
1709 unregister_pppox_proto(PX_PROTO_OL2TP);
1710 #endif
1711 out_unregister_pppol2tp_proto:
1712 proto_unregister(&pppol2tp_sk_proto);
1713 out_unregister_pppol2tp_pernet:
1714 unregister_pernet_device(&pppol2tp_net_ops);
1715 goto out;
1716 }
1717
pppol2tp_exit(void)1718 static void __exit pppol2tp_exit(void)
1719 {
1720 #ifdef CONFIG_L2TP_V3
1721 l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1722 #endif
1723 unregister_pppox_proto(PX_PROTO_OL2TP);
1724 proto_unregister(&pppol2tp_sk_proto);
1725 unregister_pernet_device(&pppol2tp_net_ops);
1726 }
1727
1728 module_init(pppol2tp_init);
1729 module_exit(pppol2tp_exit);
1730
1731 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1732 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1733 MODULE_LICENSE("GPL");
1734 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1735 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OL2TP);
1736 MODULE_ALIAS_L2TP_PWTYPE(7);
1737