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 * uservaddr,int sockaddr_len,int flags)687 static int pppol2tp_connect(struct socket *sock, struct sockaddr *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 /* The only header we need to worry about is the L2TP
791 * header. This size is different depending on whether
792 * sequence numbers are enabled for the data channel.
793 */
794 po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
795
796 po->chan.private = sk;
797 po->chan.ops = &pppol2tp_chan_ops;
798 po->chan.mtu = pppol2tp_tunnel_mtu(tunnel);
799
800 error = ppp_register_net_channel(sock_net(sk), &po->chan);
801 if (error) {
802 mutex_unlock(&ps->sk_lock);
803 goto end;
804 }
805
806 out_no_ppp:
807 /* This is how we get the session context from the socket. */
808 sock_hold(sk);
809 rcu_assign_sk_user_data(sk, session);
810 rcu_assign_pointer(ps->sk, sk);
811 mutex_unlock(&ps->sk_lock);
812
813 /* Keep the reference we've grabbed on the session: sk doesn't expect
814 * the session to disappear. pppol2tp_session_close() is responsible
815 * for dropping it.
816 */
817 drop_refcnt = false;
818
819 sk->sk_state = PPPOX_CONNECTED;
820
821 end:
822 if (error) {
823 if (new_session)
824 l2tp_session_delete(session);
825 if (new_tunnel)
826 l2tp_tunnel_delete(tunnel);
827 }
828 if (drop_refcnt)
829 l2tp_session_put(session);
830 l2tp_tunnel_put(tunnel);
831 release_sock(sk);
832
833 return error;
834 }
835
836 #ifdef CONFIG_L2TP_V3
837
838 /* 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)839 static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
840 u32 session_id, u32 peer_session_id,
841 struct l2tp_session_cfg *cfg)
842 {
843 int error;
844 struct l2tp_session *session;
845
846 /* Error if tunnel socket is not prepped */
847 if (!tunnel->sock) {
848 error = -ENOENT;
849 goto err;
850 }
851
852 /* Allocate and initialize a new session context. */
853 session = l2tp_session_create(sizeof(struct pppol2tp_session),
854 tunnel, session_id,
855 peer_session_id, cfg);
856 if (IS_ERR(session)) {
857 error = PTR_ERR(session);
858 goto err;
859 }
860
861 pppol2tp_session_init(session);
862
863 error = l2tp_session_register(session, tunnel);
864 if (error < 0)
865 goto err_sess;
866
867 return 0;
868
869 err_sess:
870 l2tp_session_put(session);
871 err:
872 return error;
873 }
874
875 #endif /* CONFIG_L2TP_V3 */
876
877 /* getname() support.
878 */
pppol2tp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)879 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
880 int peer)
881 {
882 int len = 0;
883 int error = 0;
884 struct l2tp_session *session;
885 struct l2tp_tunnel *tunnel;
886 struct sock *sk = sock->sk;
887 struct inet_sock *inet;
888 struct pppol2tp_session *pls;
889
890 error = -ENOTCONN;
891 if (!sk)
892 goto end;
893 if (!(sk->sk_state & PPPOX_CONNECTED))
894 goto end;
895
896 error = -EBADF;
897 session = pppol2tp_sock_to_session(sk);
898 if (!session)
899 goto end;
900
901 pls = l2tp_session_priv(session);
902 tunnel = session->tunnel;
903
904 inet = inet_sk(tunnel->sock);
905 if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET) {
906 struct sockaddr_pppol2tp sp;
907
908 len = sizeof(sp);
909 memset(&sp, 0, len);
910 sp.sa_family = AF_PPPOX;
911 sp.sa_protocol = PX_PROTO_OL2TP;
912 sp.pppol2tp.fd = tunnel->fd;
913 sp.pppol2tp.pid = pls->owner;
914 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
915 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
916 sp.pppol2tp.s_session = session->session_id;
917 sp.pppol2tp.d_session = session->peer_session_id;
918 sp.pppol2tp.addr.sin_family = AF_INET;
919 sp.pppol2tp.addr.sin_port = inet->inet_dport;
920 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
921 memcpy(uaddr, &sp, len);
922 #if IS_ENABLED(CONFIG_IPV6)
923 } else if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET6) {
924 struct sockaddr_pppol2tpin6 sp;
925
926 len = sizeof(sp);
927 memset(&sp, 0, len);
928 sp.sa_family = AF_PPPOX;
929 sp.sa_protocol = PX_PROTO_OL2TP;
930 sp.pppol2tp.fd = tunnel->fd;
931 sp.pppol2tp.pid = pls->owner;
932 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
933 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
934 sp.pppol2tp.s_session = session->session_id;
935 sp.pppol2tp.d_session = session->peer_session_id;
936 sp.pppol2tp.addr.sin6_family = AF_INET6;
937 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
938 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
939 sizeof(tunnel->sock->sk_v6_daddr));
940 memcpy(uaddr, &sp, len);
941 } else if (tunnel->version == 3 && tunnel->sock->sk_family == AF_INET6) {
942 struct sockaddr_pppol2tpv3in6 sp;
943
944 len = sizeof(sp);
945 memset(&sp, 0, len);
946 sp.sa_family = AF_PPPOX;
947 sp.sa_protocol = PX_PROTO_OL2TP;
948 sp.pppol2tp.fd = tunnel->fd;
949 sp.pppol2tp.pid = pls->owner;
950 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
951 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
952 sp.pppol2tp.s_session = session->session_id;
953 sp.pppol2tp.d_session = session->peer_session_id;
954 sp.pppol2tp.addr.sin6_family = AF_INET6;
955 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
956 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
957 sizeof(tunnel->sock->sk_v6_daddr));
958 memcpy(uaddr, &sp, len);
959 #endif
960 } else if (tunnel->version == 3) {
961 struct sockaddr_pppol2tpv3 sp;
962
963 len = sizeof(sp);
964 memset(&sp, 0, len);
965 sp.sa_family = AF_PPPOX;
966 sp.sa_protocol = PX_PROTO_OL2TP;
967 sp.pppol2tp.fd = tunnel->fd;
968 sp.pppol2tp.pid = pls->owner;
969 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
970 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
971 sp.pppol2tp.s_session = session->session_id;
972 sp.pppol2tp.d_session = session->peer_session_id;
973 sp.pppol2tp.addr.sin_family = AF_INET;
974 sp.pppol2tp.addr.sin_port = inet->inet_dport;
975 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
976 memcpy(uaddr, &sp, len);
977 }
978
979 error = len;
980
981 l2tp_session_put(session);
982 end:
983 return error;
984 }
985
986 /****************************************************************************
987 * ioctl() handlers.
988 *
989 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
990 * sockets. However, in order to control kernel tunnel features, we allow
991 * userspace to create a special "tunnel" PPPoX socket which is used for
992 * control only. Tunnel PPPoX sockets have session_id == 0 and simply allow
993 * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
994 * calls.
995 ****************************************************************************/
996
pppol2tp_copy_stats(struct pppol2tp_ioc_stats * dest,const struct l2tp_stats * stats)997 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
998 const struct l2tp_stats *stats)
999 {
1000 memset(dest, 0, sizeof(*dest));
1001
1002 dest->tx_packets = atomic_long_read(&stats->tx_packets);
1003 dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
1004 dest->tx_errors = atomic_long_read(&stats->tx_errors);
1005 dest->rx_packets = atomic_long_read(&stats->rx_packets);
1006 dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
1007 dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
1008 dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
1009 dest->rx_errors = atomic_long_read(&stats->rx_errors);
1010 }
1011
pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats * stats,struct l2tp_tunnel * tunnel)1012 static int pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats *stats,
1013 struct l2tp_tunnel *tunnel)
1014 {
1015 struct l2tp_session *session;
1016
1017 if (!stats->session_id) {
1018 pppol2tp_copy_stats(stats, &tunnel->stats);
1019 return 0;
1020 }
1021
1022 /* If session_id is set, search the corresponding session in the
1023 * context of this tunnel and record the session's statistics.
1024 */
1025 session = l2tp_session_get(tunnel->l2tp_net, tunnel->sock, tunnel->version,
1026 tunnel->tunnel_id, stats->session_id);
1027 if (!session)
1028 return -EBADR;
1029
1030 if (session->pwtype != L2TP_PWTYPE_PPP) {
1031 l2tp_session_put(session);
1032 return -EBADR;
1033 }
1034
1035 pppol2tp_copy_stats(stats, &session->stats);
1036 l2tp_session_put(session);
1037
1038 return 0;
1039 }
1040
pppol2tp_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)1041 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1042 unsigned long arg)
1043 {
1044 struct pppol2tp_ioc_stats stats;
1045 struct l2tp_session *session;
1046
1047 switch (cmd) {
1048 case PPPIOCGMRU:
1049 case PPPIOCGFLAGS:
1050 session = sock->sk->sk_user_data;
1051 if (!session)
1052 return -ENOTCONN;
1053
1054 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1055 return -EBADF;
1056
1057 /* Not defined for tunnels */
1058 if (!session->session_id && !session->peer_session_id)
1059 return -ENOSYS;
1060
1061 if (put_user(0, (int __user *)arg))
1062 return -EFAULT;
1063 break;
1064
1065 case PPPIOCSMRU:
1066 case PPPIOCSFLAGS:
1067 session = sock->sk->sk_user_data;
1068 if (!session)
1069 return -ENOTCONN;
1070
1071 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1072 return -EBADF;
1073
1074 /* Not defined for tunnels */
1075 if (!session->session_id && !session->peer_session_id)
1076 return -ENOSYS;
1077
1078 if (!access_ok((int __user *)arg, sizeof(int)))
1079 return -EFAULT;
1080 break;
1081
1082 case PPPIOCGL2TPSTATS:
1083 session = sock->sk->sk_user_data;
1084 if (!session)
1085 return -ENOTCONN;
1086
1087 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1088 return -EBADF;
1089
1090 /* Session 0 represents the parent tunnel */
1091 if (!session->session_id && !session->peer_session_id) {
1092 u32 session_id;
1093 int err;
1094
1095 if (copy_from_user(&stats, (void __user *)arg,
1096 sizeof(stats)))
1097 return -EFAULT;
1098
1099 session_id = stats.session_id;
1100 err = pppol2tp_tunnel_copy_stats(&stats,
1101 session->tunnel);
1102 if (err < 0)
1103 return err;
1104
1105 stats.session_id = session_id;
1106 } else {
1107 pppol2tp_copy_stats(&stats, &session->stats);
1108 stats.session_id = session->session_id;
1109 }
1110 stats.tunnel_id = session->tunnel->tunnel_id;
1111 stats.using_ipsec = l2tp_tunnel_uses_xfrm(session->tunnel);
1112
1113 if (copy_to_user((void __user *)arg, &stats, sizeof(stats)))
1114 return -EFAULT;
1115 break;
1116
1117 default:
1118 return -ENOIOCTLCMD;
1119 }
1120
1121 return 0;
1122 }
1123
1124 /*****************************************************************************
1125 * setsockopt() / getsockopt() support.
1126 *
1127 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1128 * sockets. In order to control kernel tunnel features, we allow userspace to
1129 * create a special "tunnel" PPPoX socket which is used for control only.
1130 * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1131 * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1132 *****************************************************************************/
1133
1134 /* Tunnel setsockopt() helper.
1135 */
pppol2tp_tunnel_setsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int val)1136 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1137 struct l2tp_tunnel *tunnel,
1138 int optname, int val)
1139 {
1140 int err = 0;
1141
1142 switch (optname) {
1143 case PPPOL2TP_SO_DEBUG:
1144 /* Tunnel debug flags option is deprecated */
1145 break;
1146
1147 default:
1148 err = -ENOPROTOOPT;
1149 break;
1150 }
1151
1152 return err;
1153 }
1154
1155 /* Session setsockopt helper.
1156 */
pppol2tp_session_setsockopt(struct sock * sk,struct l2tp_session * session,int optname,int val)1157 static int pppol2tp_session_setsockopt(struct sock *sk,
1158 struct l2tp_session *session,
1159 int optname, int val)
1160 {
1161 int err = 0;
1162
1163 switch (optname) {
1164 case PPPOL2TP_SO_RECVSEQ:
1165 if (val != 0 && val != 1) {
1166 err = -EINVAL;
1167 break;
1168 }
1169 session->recv_seq = !!val;
1170 break;
1171
1172 case PPPOL2TP_SO_SENDSEQ:
1173 if (val != 0 && val != 1) {
1174 err = -EINVAL;
1175 break;
1176 }
1177 session->send_seq = !!val;
1178 {
1179 struct pppox_sock *po = pppox_sk(sk);
1180
1181 po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1182 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1183 }
1184 l2tp_session_set_header_len(session, session->tunnel->version,
1185 session->tunnel->encap);
1186 break;
1187
1188 case PPPOL2TP_SO_LNSMODE:
1189 if (val != 0 && val != 1) {
1190 err = -EINVAL;
1191 break;
1192 }
1193 session->lns_mode = !!val;
1194 break;
1195
1196 case PPPOL2TP_SO_DEBUG:
1197 /* Session debug flags option is deprecated */
1198 break;
1199
1200 case PPPOL2TP_SO_REORDERTO:
1201 session->reorder_timeout = msecs_to_jiffies(val);
1202 break;
1203
1204 default:
1205 err = -ENOPROTOOPT;
1206 break;
1207 }
1208
1209 return err;
1210 }
1211
1212 /* Main setsockopt() entry point.
1213 * Does API checks, then calls either the tunnel or session setsockopt
1214 * handler, according to whether the PPPoL2TP socket is a for a regular
1215 * session or the special tunnel type.
1216 */
pppol2tp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1217 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1218 sockptr_t optval, unsigned int optlen)
1219 {
1220 struct sock *sk = sock->sk;
1221 struct l2tp_session *session;
1222 struct l2tp_tunnel *tunnel;
1223 int val;
1224 int err;
1225
1226 if (level != SOL_PPPOL2TP)
1227 return -EINVAL;
1228
1229 if (optlen < sizeof(int))
1230 return -EINVAL;
1231
1232 if (copy_from_sockptr(&val, optval, sizeof(int)))
1233 return -EFAULT;
1234
1235 err = -ENOTCONN;
1236 if (!sk->sk_user_data)
1237 goto end;
1238
1239 /* Get session context from the socket */
1240 err = -EBADF;
1241 session = pppol2tp_sock_to_session(sk);
1242 if (!session)
1243 goto end;
1244
1245 /* Special case: if session_id == 0x0000, treat as operation on tunnel
1246 */
1247 if (session->session_id == 0 && session->peer_session_id == 0) {
1248 tunnel = session->tunnel;
1249 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1250 } else {
1251 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1252 }
1253
1254 l2tp_session_put(session);
1255 end:
1256 return err;
1257 }
1258
1259 /* Tunnel getsockopt helper. Called with sock locked.
1260 */
pppol2tp_tunnel_getsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int * val)1261 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1262 struct l2tp_tunnel *tunnel,
1263 int optname, int *val)
1264 {
1265 int err = 0;
1266
1267 switch (optname) {
1268 case PPPOL2TP_SO_DEBUG:
1269 /* Tunnel debug flags option is deprecated */
1270 *val = 0;
1271 break;
1272
1273 default:
1274 err = -ENOPROTOOPT;
1275 break;
1276 }
1277
1278 return err;
1279 }
1280
1281 /* Session getsockopt helper. Called with sock locked.
1282 */
pppol2tp_session_getsockopt(struct sock * sk,struct l2tp_session * session,int optname,int * val)1283 static int pppol2tp_session_getsockopt(struct sock *sk,
1284 struct l2tp_session *session,
1285 int optname, int *val)
1286 {
1287 int err = 0;
1288
1289 switch (optname) {
1290 case PPPOL2TP_SO_RECVSEQ:
1291 *val = session->recv_seq;
1292 break;
1293
1294 case PPPOL2TP_SO_SENDSEQ:
1295 *val = session->send_seq;
1296 break;
1297
1298 case PPPOL2TP_SO_LNSMODE:
1299 *val = session->lns_mode;
1300 break;
1301
1302 case PPPOL2TP_SO_DEBUG:
1303 /* Session debug flags option is deprecated */
1304 *val = 0;
1305 break;
1306
1307 case PPPOL2TP_SO_REORDERTO:
1308 *val = (int)jiffies_to_msecs(session->reorder_timeout);
1309 break;
1310
1311 default:
1312 err = -ENOPROTOOPT;
1313 }
1314
1315 return err;
1316 }
1317
1318 /* Main getsockopt() entry point.
1319 * Does API checks, then calls either the tunnel or session getsockopt
1320 * handler, according to whether the PPPoX socket is a for a regular session
1321 * or the special tunnel type.
1322 */
pppol2tp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1323 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1324 char __user *optval, int __user *optlen)
1325 {
1326 struct sock *sk = sock->sk;
1327 struct l2tp_session *session;
1328 struct l2tp_tunnel *tunnel;
1329 int val, len;
1330 int err;
1331
1332 if (level != SOL_PPPOL2TP)
1333 return -EINVAL;
1334
1335 if (get_user(len, optlen))
1336 return -EFAULT;
1337
1338 if (len < 0)
1339 return -EINVAL;
1340
1341 len = min_t(unsigned int, len, sizeof(int));
1342
1343 err = -ENOTCONN;
1344 if (!sk->sk_user_data)
1345 goto end;
1346
1347 /* Get the session context */
1348 err = -EBADF;
1349 session = pppol2tp_sock_to_session(sk);
1350 if (!session)
1351 goto end;
1352
1353 /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1354 if (session->session_id == 0 && session->peer_session_id == 0) {
1355 tunnel = session->tunnel;
1356 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1357 if (err)
1358 goto end_put_sess;
1359 } else {
1360 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1361 if (err)
1362 goto end_put_sess;
1363 }
1364
1365 err = -EFAULT;
1366 if (put_user(len, optlen))
1367 goto end_put_sess;
1368
1369 if (copy_to_user((void __user *)optval, &val, len))
1370 goto end_put_sess;
1371
1372 err = 0;
1373
1374 end_put_sess:
1375 l2tp_session_put(session);
1376 end:
1377 return err;
1378 }
1379
1380 /*****************************************************************************
1381 * /proc filesystem for debug
1382 * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1383 * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1384 *****************************************************************************/
1385
1386 #ifdef CONFIG_PROC_FS
1387
1388 struct pppol2tp_seq_data {
1389 struct seq_net_private p;
1390 unsigned long tkey; /* lookup key of current tunnel */
1391 unsigned long skey; /* lookup key of current session */
1392 struct l2tp_tunnel *tunnel;
1393 struct l2tp_session *session; /* NULL means get next tunnel */
1394 };
1395
pppol2tp_next_tunnel(struct net * net,struct pppol2tp_seq_data * pd)1396 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1397 {
1398 /* Drop reference taken during previous invocation */
1399 if (pd->tunnel)
1400 l2tp_tunnel_put(pd->tunnel);
1401
1402 for (;;) {
1403 pd->tunnel = l2tp_tunnel_get_next(net, &pd->tkey);
1404 pd->tkey++;
1405
1406 /* Only accept L2TPv2 tunnels */
1407 if (!pd->tunnel || pd->tunnel->version == 2)
1408 return;
1409
1410 l2tp_tunnel_put(pd->tunnel);
1411 }
1412 }
1413
pppol2tp_next_session(struct net * net,struct pppol2tp_seq_data * pd)1414 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1415 {
1416 /* Drop reference taken during previous invocation */
1417 if (pd->session)
1418 l2tp_session_put(pd->session);
1419
1420 pd->session = l2tp_session_get_next(net, pd->tunnel->sock,
1421 pd->tunnel->version,
1422 pd->tunnel->tunnel_id, &pd->skey);
1423 pd->skey++;
1424
1425 if (!pd->session) {
1426 pd->skey = 0;
1427 pppol2tp_next_tunnel(net, pd);
1428 }
1429 }
1430
pppol2tp_seq_start(struct seq_file * m,loff_t * offs)1431 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1432 {
1433 struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1434 loff_t pos = *offs;
1435 struct net *net;
1436
1437 if (!pos)
1438 goto out;
1439
1440 if (WARN_ON(!m->private)) {
1441 pd = NULL;
1442 goto out;
1443 }
1444
1445 pd = m->private;
1446 net = seq_file_net(m);
1447
1448 if (!pd->tunnel)
1449 pppol2tp_next_tunnel(net, pd);
1450 else
1451 pppol2tp_next_session(net, pd);
1452
1453 /* NULL tunnel and session indicates end of list */
1454 if (!pd->tunnel && !pd->session)
1455 pd = NULL;
1456
1457 out:
1458 return pd;
1459 }
1460
pppol2tp_seq_next(struct seq_file * m,void * v,loff_t * pos)1461 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1462 {
1463 (*pos)++;
1464 return NULL;
1465 }
1466
pppol2tp_seq_stop(struct seq_file * p,void * v)1467 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1468 {
1469 struct pppol2tp_seq_data *pd = v;
1470
1471 if (!pd || pd == SEQ_START_TOKEN)
1472 return;
1473
1474 /* Drop reference taken by last invocation of pppol2tp_next_session()
1475 * or pppol2tp_next_tunnel().
1476 */
1477 if (pd->session) {
1478 l2tp_session_put(pd->session);
1479 pd->session = NULL;
1480 }
1481 if (pd->tunnel) {
1482 l2tp_tunnel_put(pd->tunnel);
1483 pd->tunnel = NULL;
1484 }
1485 }
1486
pppol2tp_seq_tunnel_show(struct seq_file * m,void * v)1487 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1488 {
1489 struct l2tp_tunnel *tunnel = v;
1490
1491 seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1492 tunnel->name,
1493 tunnel->sock ? 'Y' : 'N',
1494 refcount_read(&tunnel->ref_count) - 1);
1495 seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1496 0,
1497 atomic_long_read(&tunnel->stats.tx_packets),
1498 atomic_long_read(&tunnel->stats.tx_bytes),
1499 atomic_long_read(&tunnel->stats.tx_errors),
1500 atomic_long_read(&tunnel->stats.rx_packets),
1501 atomic_long_read(&tunnel->stats.rx_bytes),
1502 atomic_long_read(&tunnel->stats.rx_errors));
1503 }
1504
pppol2tp_seq_session_show(struct seq_file * m,void * v)1505 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1506 {
1507 struct l2tp_session *session = v;
1508 struct l2tp_tunnel *tunnel = session->tunnel;
1509 unsigned char state;
1510 char user_data_ok;
1511 struct sock *sk;
1512 u32 ip = 0;
1513 u16 port = 0;
1514
1515 if (tunnel->sock) {
1516 struct inet_sock *inet = inet_sk(tunnel->sock);
1517
1518 ip = ntohl(inet->inet_saddr);
1519 port = ntohs(inet->inet_sport);
1520 }
1521
1522 rcu_read_lock();
1523 sk = pppol2tp_session_get_sock(session);
1524 if (sk) {
1525 state = sk->sk_state;
1526 user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';
1527 } else {
1528 state = 0;
1529 user_data_ok = 'N';
1530 }
1531
1532 seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> %04X/%04X %d %c\n",
1533 session->name, ip, port,
1534 tunnel->tunnel_id,
1535 session->session_id,
1536 tunnel->peer_tunnel_id,
1537 session->peer_session_id,
1538 state, user_data_ok);
1539 seq_printf(m, " 0/0/%c/%c/%s %08x %u\n",
1540 session->recv_seq ? 'R' : '-',
1541 session->send_seq ? 'S' : '-',
1542 session->lns_mode ? "LNS" : "LAC",
1543 0,
1544 jiffies_to_msecs(session->reorder_timeout));
1545 seq_printf(m, " %u/%u %ld/%ld/%ld %ld/%ld/%ld\n",
1546 session->nr, session->ns,
1547 atomic_long_read(&session->stats.tx_packets),
1548 atomic_long_read(&session->stats.tx_bytes),
1549 atomic_long_read(&session->stats.tx_errors),
1550 atomic_long_read(&session->stats.rx_packets),
1551 atomic_long_read(&session->stats.rx_bytes),
1552 atomic_long_read(&session->stats.rx_errors));
1553
1554 if (sk) {
1555 struct pppox_sock *po = pppox_sk(sk);
1556
1557 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
1558 }
1559 rcu_read_unlock();
1560 }
1561
pppol2tp_seq_show(struct seq_file * m,void * v)1562 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1563 {
1564 struct pppol2tp_seq_data *pd = v;
1565
1566 /* display header on line 1 */
1567 if (v == SEQ_START_TOKEN) {
1568 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1569 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1570 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1571 seq_puts(m, " SESSION name, addr/port src-tid/sid dest-tid/sid state user-data-ok\n");
1572 seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1573 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1574 goto out;
1575 }
1576
1577 if (!pd->session)
1578 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1579 else
1580 pppol2tp_seq_session_show(m, pd->session);
1581
1582 out:
1583 return 0;
1584 }
1585
1586 static const struct seq_operations pppol2tp_seq_ops = {
1587 .start = pppol2tp_seq_start,
1588 .next = pppol2tp_seq_next,
1589 .stop = pppol2tp_seq_stop,
1590 .show = pppol2tp_seq_show,
1591 };
1592 #endif /* CONFIG_PROC_FS */
1593
1594 /*****************************************************************************
1595 * Network namespace
1596 *****************************************************************************/
1597
pppol2tp_init_net(struct net * net)1598 static __net_init int pppol2tp_init_net(struct net *net)
1599 {
1600 struct proc_dir_entry *pde;
1601 int err = 0;
1602
1603 pde = proc_create_net("pppol2tp", 0444, net->proc_net,
1604 &pppol2tp_seq_ops, sizeof(struct pppol2tp_seq_data));
1605 if (!pde) {
1606 err = -ENOMEM;
1607 goto out;
1608 }
1609
1610 out:
1611 return err;
1612 }
1613
pppol2tp_exit_net(struct net * net)1614 static __net_exit void pppol2tp_exit_net(struct net *net)
1615 {
1616 remove_proc_entry("pppol2tp", net->proc_net);
1617 }
1618
1619 static struct pernet_operations pppol2tp_net_ops = {
1620 .init = pppol2tp_init_net,
1621 .exit = pppol2tp_exit_net,
1622 };
1623
1624 /*****************************************************************************
1625 * Init and cleanup
1626 *****************************************************************************/
1627
1628 static const struct proto_ops pppol2tp_ops = {
1629 .family = AF_PPPOX,
1630 .owner = THIS_MODULE,
1631 .release = pppol2tp_release,
1632 .bind = sock_no_bind,
1633 .connect = pppol2tp_connect,
1634 .socketpair = sock_no_socketpair,
1635 .accept = sock_no_accept,
1636 .getname = pppol2tp_getname,
1637 .poll = datagram_poll,
1638 .listen = sock_no_listen,
1639 .shutdown = sock_no_shutdown,
1640 .setsockopt = pppol2tp_setsockopt,
1641 .getsockopt = pppol2tp_getsockopt,
1642 .sendmsg = pppol2tp_sendmsg,
1643 .recvmsg = pppol2tp_recvmsg,
1644 .mmap = sock_no_mmap,
1645 .ioctl = pppox_ioctl,
1646 #ifdef CONFIG_COMPAT
1647 .compat_ioctl = pppox_compat_ioctl,
1648 #endif
1649 };
1650
1651 static const struct pppox_proto pppol2tp_proto = {
1652 .create = pppol2tp_create,
1653 .ioctl = pppol2tp_ioctl,
1654 .owner = THIS_MODULE,
1655 };
1656
1657 #ifdef CONFIG_L2TP_V3
1658
1659 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1660 .session_create = pppol2tp_session_create,
1661 .session_delete = l2tp_session_delete,
1662 };
1663
1664 #endif /* CONFIG_L2TP_V3 */
1665
pppol2tp_init(void)1666 static int __init pppol2tp_init(void)
1667 {
1668 int err;
1669
1670 err = register_pernet_device(&pppol2tp_net_ops);
1671 if (err)
1672 goto out;
1673
1674 err = proto_register(&pppol2tp_sk_proto, 0);
1675 if (err)
1676 goto out_unregister_pppol2tp_pernet;
1677
1678 err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1679 if (err)
1680 goto out_unregister_pppol2tp_proto;
1681
1682 #ifdef CONFIG_L2TP_V3
1683 err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1684 if (err)
1685 goto out_unregister_pppox;
1686 #endif
1687
1688 pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1689
1690 out:
1691 return err;
1692
1693 #ifdef CONFIG_L2TP_V3
1694 out_unregister_pppox:
1695 unregister_pppox_proto(PX_PROTO_OL2TP);
1696 #endif
1697 out_unregister_pppol2tp_proto:
1698 proto_unregister(&pppol2tp_sk_proto);
1699 out_unregister_pppol2tp_pernet:
1700 unregister_pernet_device(&pppol2tp_net_ops);
1701 goto out;
1702 }
1703
pppol2tp_exit(void)1704 static void __exit pppol2tp_exit(void)
1705 {
1706 #ifdef CONFIG_L2TP_V3
1707 l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1708 #endif
1709 unregister_pppox_proto(PX_PROTO_OL2TP);
1710 proto_unregister(&pppol2tp_sk_proto);
1711 unregister_pernet_device(&pppol2tp_net_ops);
1712 }
1713
1714 module_init(pppol2tp_init);
1715 module_exit(pppol2tp_exit);
1716
1717 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1718 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1719 MODULE_LICENSE("GPL");
1720 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1721 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OL2TP);
1722 MODULE_ALIAS_L2TP_PWTYPE(7);
1723