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 po->chan.direct_xmit = true;
800
801 error = ppp_register_net_channel(sock_net(sk), &po->chan);
802 if (error) {
803 mutex_unlock(&ps->sk_lock);
804 goto end;
805 }
806
807 out_no_ppp:
808 /* This is how we get the session context from the socket. */
809 sock_hold(sk);
810 rcu_assign_sk_user_data(sk, session);
811 rcu_assign_pointer(ps->sk, sk);
812 mutex_unlock(&ps->sk_lock);
813
814 /* Keep the reference we've grabbed on the session: sk doesn't expect
815 * the session to disappear. pppol2tp_session_close() is responsible
816 * for dropping it.
817 */
818 drop_refcnt = false;
819
820 sk->sk_state = PPPOX_CONNECTED;
821
822 end:
823 if (error) {
824 if (new_session)
825 l2tp_session_delete(session);
826 if (new_tunnel)
827 l2tp_tunnel_delete(tunnel);
828 }
829 if (drop_refcnt)
830 l2tp_session_put(session);
831 l2tp_tunnel_put(tunnel);
832 release_sock(sk);
833
834 return error;
835 }
836
837 #ifdef CONFIG_L2TP_V3
838
839 /* 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)840 static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
841 u32 session_id, u32 peer_session_id,
842 struct l2tp_session_cfg *cfg)
843 {
844 int error;
845 struct l2tp_session *session;
846
847 /* Error if tunnel socket is not prepped */
848 if (!tunnel->sock) {
849 error = -ENOENT;
850 goto err;
851 }
852
853 /* Allocate and initialize a new session context. */
854 session = l2tp_session_create(sizeof(struct pppol2tp_session),
855 tunnel, session_id,
856 peer_session_id, cfg);
857 if (IS_ERR(session)) {
858 error = PTR_ERR(session);
859 goto err;
860 }
861
862 pppol2tp_session_init(session);
863
864 error = l2tp_session_register(session, tunnel);
865 if (error < 0)
866 goto err_sess;
867
868 return 0;
869
870 err_sess:
871 l2tp_session_put(session);
872 err:
873 return error;
874 }
875
876 #endif /* CONFIG_L2TP_V3 */
877
878 /* getname() support.
879 */
pppol2tp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)880 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
881 int peer)
882 {
883 int len = 0;
884 int error = 0;
885 struct l2tp_session *session;
886 struct l2tp_tunnel *tunnel;
887 struct sock *sk = sock->sk;
888 struct inet_sock *inet;
889 struct pppol2tp_session *pls;
890
891 error = -ENOTCONN;
892 if (!sk)
893 goto end;
894 if (!(sk->sk_state & PPPOX_CONNECTED))
895 goto end;
896
897 error = -EBADF;
898 session = pppol2tp_sock_to_session(sk);
899 if (!session)
900 goto end;
901
902 pls = l2tp_session_priv(session);
903 tunnel = session->tunnel;
904
905 inet = inet_sk(tunnel->sock);
906 if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET) {
907 struct sockaddr_pppol2tp sp;
908
909 len = sizeof(sp);
910 memset(&sp, 0, len);
911 sp.sa_family = AF_PPPOX;
912 sp.sa_protocol = PX_PROTO_OL2TP;
913 sp.pppol2tp.fd = tunnel->fd;
914 sp.pppol2tp.pid = pls->owner;
915 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
916 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
917 sp.pppol2tp.s_session = session->session_id;
918 sp.pppol2tp.d_session = session->peer_session_id;
919 sp.pppol2tp.addr.sin_family = AF_INET;
920 sp.pppol2tp.addr.sin_port = inet->inet_dport;
921 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
922 memcpy(uaddr, &sp, len);
923 #if IS_ENABLED(CONFIG_IPV6)
924 } else if (tunnel->version == 2 && tunnel->sock->sk_family == AF_INET6) {
925 struct sockaddr_pppol2tpin6 sp;
926
927 len = sizeof(sp);
928 memset(&sp, 0, len);
929 sp.sa_family = AF_PPPOX;
930 sp.sa_protocol = PX_PROTO_OL2TP;
931 sp.pppol2tp.fd = tunnel->fd;
932 sp.pppol2tp.pid = pls->owner;
933 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
934 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
935 sp.pppol2tp.s_session = session->session_id;
936 sp.pppol2tp.d_session = session->peer_session_id;
937 sp.pppol2tp.addr.sin6_family = AF_INET6;
938 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
939 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
940 sizeof(tunnel->sock->sk_v6_daddr));
941 memcpy(uaddr, &sp, len);
942 } else if (tunnel->version == 3 && tunnel->sock->sk_family == AF_INET6) {
943 struct sockaddr_pppol2tpv3in6 sp;
944
945 len = sizeof(sp);
946 memset(&sp, 0, len);
947 sp.sa_family = AF_PPPOX;
948 sp.sa_protocol = PX_PROTO_OL2TP;
949 sp.pppol2tp.fd = tunnel->fd;
950 sp.pppol2tp.pid = pls->owner;
951 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
952 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
953 sp.pppol2tp.s_session = session->session_id;
954 sp.pppol2tp.d_session = session->peer_session_id;
955 sp.pppol2tp.addr.sin6_family = AF_INET6;
956 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
957 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
958 sizeof(tunnel->sock->sk_v6_daddr));
959 memcpy(uaddr, &sp, len);
960 #endif
961 } else if (tunnel->version == 3) {
962 struct sockaddr_pppol2tpv3 sp;
963
964 len = sizeof(sp);
965 memset(&sp, 0, len);
966 sp.sa_family = AF_PPPOX;
967 sp.sa_protocol = PX_PROTO_OL2TP;
968 sp.pppol2tp.fd = tunnel->fd;
969 sp.pppol2tp.pid = pls->owner;
970 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
971 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
972 sp.pppol2tp.s_session = session->session_id;
973 sp.pppol2tp.d_session = session->peer_session_id;
974 sp.pppol2tp.addr.sin_family = AF_INET;
975 sp.pppol2tp.addr.sin_port = inet->inet_dport;
976 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
977 memcpy(uaddr, &sp, len);
978 }
979
980 error = len;
981
982 l2tp_session_put(session);
983 end:
984 return error;
985 }
986
987 /****************************************************************************
988 * ioctl() handlers.
989 *
990 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
991 * sockets. However, in order to control kernel tunnel features, we allow
992 * userspace to create a special "tunnel" PPPoX socket which is used for
993 * control only. Tunnel PPPoX sockets have session_id == 0 and simply allow
994 * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
995 * calls.
996 ****************************************************************************/
997
pppol2tp_copy_stats(struct pppol2tp_ioc_stats * dest,const struct l2tp_stats * stats)998 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
999 const struct l2tp_stats *stats)
1000 {
1001 memset(dest, 0, sizeof(*dest));
1002
1003 dest->tx_packets = atomic_long_read(&stats->tx_packets);
1004 dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
1005 dest->tx_errors = atomic_long_read(&stats->tx_errors);
1006 dest->rx_packets = atomic_long_read(&stats->rx_packets);
1007 dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
1008 dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
1009 dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
1010 dest->rx_errors = atomic_long_read(&stats->rx_errors);
1011 }
1012
pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats * stats,struct l2tp_tunnel * tunnel)1013 static int pppol2tp_tunnel_copy_stats(struct pppol2tp_ioc_stats *stats,
1014 struct l2tp_tunnel *tunnel)
1015 {
1016 struct l2tp_session *session;
1017
1018 if (!stats->session_id) {
1019 pppol2tp_copy_stats(stats, &tunnel->stats);
1020 return 0;
1021 }
1022
1023 /* If session_id is set, search the corresponding session in the
1024 * context of this tunnel and record the session's statistics.
1025 */
1026 session = l2tp_session_get(tunnel->l2tp_net, tunnel->sock, tunnel->version,
1027 tunnel->tunnel_id, stats->session_id);
1028 if (!session)
1029 return -EBADR;
1030
1031 if (session->pwtype != L2TP_PWTYPE_PPP) {
1032 l2tp_session_put(session);
1033 return -EBADR;
1034 }
1035
1036 pppol2tp_copy_stats(stats, &session->stats);
1037 l2tp_session_put(session);
1038
1039 return 0;
1040 }
1041
pppol2tp_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)1042 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1043 unsigned long arg)
1044 {
1045 struct pppol2tp_ioc_stats stats;
1046 struct l2tp_session *session;
1047
1048 switch (cmd) {
1049 case PPPIOCGMRU:
1050 case PPPIOCGFLAGS:
1051 session = sock->sk->sk_user_data;
1052 if (!session)
1053 return -ENOTCONN;
1054
1055 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1056 return -EBADF;
1057
1058 /* Not defined for tunnels */
1059 if (!session->session_id && !session->peer_session_id)
1060 return -ENOSYS;
1061
1062 if (put_user(0, (int __user *)arg))
1063 return -EFAULT;
1064 break;
1065
1066 case PPPIOCSMRU:
1067 case PPPIOCSFLAGS:
1068 session = sock->sk->sk_user_data;
1069 if (!session)
1070 return -ENOTCONN;
1071
1072 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1073 return -EBADF;
1074
1075 /* Not defined for tunnels */
1076 if (!session->session_id && !session->peer_session_id)
1077 return -ENOSYS;
1078
1079 if (!access_ok((int __user *)arg, sizeof(int)))
1080 return -EFAULT;
1081 break;
1082
1083 case PPPIOCGL2TPSTATS:
1084 session = sock->sk->sk_user_data;
1085 if (!session)
1086 return -ENOTCONN;
1087
1088 if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
1089 return -EBADF;
1090
1091 /* Session 0 represents the parent tunnel */
1092 if (!session->session_id && !session->peer_session_id) {
1093 u32 session_id;
1094 int err;
1095
1096 if (copy_from_user(&stats, (void __user *)arg,
1097 sizeof(stats)))
1098 return -EFAULT;
1099
1100 session_id = stats.session_id;
1101 err = pppol2tp_tunnel_copy_stats(&stats,
1102 session->tunnel);
1103 if (err < 0)
1104 return err;
1105
1106 stats.session_id = session_id;
1107 } else {
1108 pppol2tp_copy_stats(&stats, &session->stats);
1109 stats.session_id = session->session_id;
1110 }
1111 stats.tunnel_id = session->tunnel->tunnel_id;
1112 stats.using_ipsec = l2tp_tunnel_uses_xfrm(session->tunnel);
1113
1114 if (copy_to_user((void __user *)arg, &stats, sizeof(stats)))
1115 return -EFAULT;
1116 break;
1117
1118 default:
1119 return -ENOIOCTLCMD;
1120 }
1121
1122 return 0;
1123 }
1124
1125 /*****************************************************************************
1126 * setsockopt() / getsockopt() support.
1127 *
1128 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1129 * sockets. In order to control kernel tunnel features, we allow userspace to
1130 * create a special "tunnel" PPPoX socket which is used for control only.
1131 * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1132 * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1133 *****************************************************************************/
1134
1135 /* Tunnel setsockopt() helper.
1136 */
pppol2tp_tunnel_setsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int val)1137 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1138 struct l2tp_tunnel *tunnel,
1139 int optname, int val)
1140 {
1141 int err = 0;
1142
1143 switch (optname) {
1144 case PPPOL2TP_SO_DEBUG:
1145 /* Tunnel debug flags option is deprecated */
1146 break;
1147
1148 default:
1149 err = -ENOPROTOOPT;
1150 break;
1151 }
1152
1153 return err;
1154 }
1155
1156 /* Session setsockopt helper.
1157 */
pppol2tp_session_setsockopt(struct sock * sk,struct l2tp_session * session,int optname,int val)1158 static int pppol2tp_session_setsockopt(struct sock *sk,
1159 struct l2tp_session *session,
1160 int optname, int val)
1161 {
1162 int err = 0;
1163
1164 switch (optname) {
1165 case PPPOL2TP_SO_RECVSEQ:
1166 if (val != 0 && val != 1) {
1167 err = -EINVAL;
1168 break;
1169 }
1170 session->recv_seq = !!val;
1171 break;
1172
1173 case PPPOL2TP_SO_SENDSEQ:
1174 if (val != 0 && val != 1) {
1175 err = -EINVAL;
1176 break;
1177 }
1178 session->send_seq = !!val;
1179 {
1180 struct pppox_sock *po = pppox_sk(sk);
1181
1182 po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1183 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1184 }
1185 l2tp_session_set_header_len(session, session->tunnel->version,
1186 session->tunnel->encap);
1187 break;
1188
1189 case PPPOL2TP_SO_LNSMODE:
1190 if (val != 0 && val != 1) {
1191 err = -EINVAL;
1192 break;
1193 }
1194 session->lns_mode = !!val;
1195 break;
1196
1197 case PPPOL2TP_SO_DEBUG:
1198 /* Session debug flags option is deprecated */
1199 break;
1200
1201 case PPPOL2TP_SO_REORDERTO:
1202 session->reorder_timeout = msecs_to_jiffies(val);
1203 break;
1204
1205 default:
1206 err = -ENOPROTOOPT;
1207 break;
1208 }
1209
1210 return err;
1211 }
1212
1213 /* Main setsockopt() entry point.
1214 * Does API checks, then calls either the tunnel or session setsockopt
1215 * handler, according to whether the PPPoL2TP socket is a for a regular
1216 * session or the special tunnel type.
1217 */
pppol2tp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1218 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1219 sockptr_t optval, unsigned int optlen)
1220 {
1221 struct sock *sk = sock->sk;
1222 struct l2tp_session *session;
1223 struct l2tp_tunnel *tunnel;
1224 int val;
1225 int err;
1226
1227 if (level != SOL_PPPOL2TP)
1228 return -EINVAL;
1229
1230 if (optlen < sizeof(int))
1231 return -EINVAL;
1232
1233 if (copy_from_sockptr(&val, optval, sizeof(int)))
1234 return -EFAULT;
1235
1236 err = -ENOTCONN;
1237 if (!sk->sk_user_data)
1238 goto end;
1239
1240 /* Get session context from the socket */
1241 err = -EBADF;
1242 session = pppol2tp_sock_to_session(sk);
1243 if (!session)
1244 goto end;
1245
1246 /* Special case: if session_id == 0x0000, treat as operation on tunnel
1247 */
1248 if (session->session_id == 0 && session->peer_session_id == 0) {
1249 tunnel = session->tunnel;
1250 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1251 } else {
1252 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1253 }
1254
1255 l2tp_session_put(session);
1256 end:
1257 return err;
1258 }
1259
1260 /* Tunnel getsockopt helper. Called with sock locked.
1261 */
pppol2tp_tunnel_getsockopt(struct sock * sk,struct l2tp_tunnel * tunnel,int optname,int * val)1262 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1263 struct l2tp_tunnel *tunnel,
1264 int optname, int *val)
1265 {
1266 int err = 0;
1267
1268 switch (optname) {
1269 case PPPOL2TP_SO_DEBUG:
1270 /* Tunnel debug flags option is deprecated */
1271 *val = 0;
1272 break;
1273
1274 default:
1275 err = -ENOPROTOOPT;
1276 break;
1277 }
1278
1279 return err;
1280 }
1281
1282 /* Session getsockopt helper. Called with sock locked.
1283 */
pppol2tp_session_getsockopt(struct sock * sk,struct l2tp_session * session,int optname,int * val)1284 static int pppol2tp_session_getsockopt(struct sock *sk,
1285 struct l2tp_session *session,
1286 int optname, int *val)
1287 {
1288 int err = 0;
1289
1290 switch (optname) {
1291 case PPPOL2TP_SO_RECVSEQ:
1292 *val = session->recv_seq;
1293 break;
1294
1295 case PPPOL2TP_SO_SENDSEQ:
1296 *val = session->send_seq;
1297 break;
1298
1299 case PPPOL2TP_SO_LNSMODE:
1300 *val = session->lns_mode;
1301 break;
1302
1303 case PPPOL2TP_SO_DEBUG:
1304 /* Session debug flags option is deprecated */
1305 *val = 0;
1306 break;
1307
1308 case PPPOL2TP_SO_REORDERTO:
1309 *val = (int)jiffies_to_msecs(session->reorder_timeout);
1310 break;
1311
1312 default:
1313 err = -ENOPROTOOPT;
1314 }
1315
1316 return err;
1317 }
1318
1319 /* Main getsockopt() entry point.
1320 * Does API checks, then calls either the tunnel or session getsockopt
1321 * handler, according to whether the PPPoX socket is a for a regular session
1322 * or the special tunnel type.
1323 */
pppol2tp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1324 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1325 char __user *optval, int __user *optlen)
1326 {
1327 struct sock *sk = sock->sk;
1328 struct l2tp_session *session;
1329 struct l2tp_tunnel *tunnel;
1330 int val, len;
1331 int err;
1332
1333 if (level != SOL_PPPOL2TP)
1334 return -EINVAL;
1335
1336 if (get_user(len, optlen))
1337 return -EFAULT;
1338
1339 if (len < 0)
1340 return -EINVAL;
1341
1342 len = min_t(unsigned int, len, sizeof(int));
1343
1344 err = -ENOTCONN;
1345 if (!sk->sk_user_data)
1346 goto end;
1347
1348 /* Get the session context */
1349 err = -EBADF;
1350 session = pppol2tp_sock_to_session(sk);
1351 if (!session)
1352 goto end;
1353
1354 /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1355 if (session->session_id == 0 && session->peer_session_id == 0) {
1356 tunnel = session->tunnel;
1357 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1358 if (err)
1359 goto end_put_sess;
1360 } else {
1361 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1362 if (err)
1363 goto end_put_sess;
1364 }
1365
1366 err = -EFAULT;
1367 if (put_user(len, optlen))
1368 goto end_put_sess;
1369
1370 if (copy_to_user((void __user *)optval, &val, len))
1371 goto end_put_sess;
1372
1373 err = 0;
1374
1375 end_put_sess:
1376 l2tp_session_put(session);
1377 end:
1378 return err;
1379 }
1380
1381 /*****************************************************************************
1382 * /proc filesystem for debug
1383 * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1384 * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1385 *****************************************************************************/
1386
1387 #ifdef CONFIG_PROC_FS
1388
1389 struct pppol2tp_seq_data {
1390 struct seq_net_private p;
1391 unsigned long tkey; /* lookup key of current tunnel */
1392 unsigned long skey; /* lookup key of current session */
1393 struct l2tp_tunnel *tunnel;
1394 struct l2tp_session *session; /* NULL means get next tunnel */
1395 };
1396
pppol2tp_next_tunnel(struct net * net,struct pppol2tp_seq_data * pd)1397 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1398 {
1399 /* Drop reference taken during previous invocation */
1400 if (pd->tunnel)
1401 l2tp_tunnel_put(pd->tunnel);
1402
1403 for (;;) {
1404 pd->tunnel = l2tp_tunnel_get_next(net, &pd->tkey);
1405 pd->tkey++;
1406
1407 /* Only accept L2TPv2 tunnels */
1408 if (!pd->tunnel || pd->tunnel->version == 2)
1409 return;
1410
1411 l2tp_tunnel_put(pd->tunnel);
1412 }
1413 }
1414
pppol2tp_next_session(struct net * net,struct pppol2tp_seq_data * pd)1415 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1416 {
1417 /* Drop reference taken during previous invocation */
1418 if (pd->session)
1419 l2tp_session_put(pd->session);
1420
1421 pd->session = l2tp_session_get_next(net, pd->tunnel->sock,
1422 pd->tunnel->version,
1423 pd->tunnel->tunnel_id, &pd->skey);
1424 pd->skey++;
1425
1426 if (!pd->session) {
1427 pd->skey = 0;
1428 pppol2tp_next_tunnel(net, pd);
1429 }
1430 }
1431
pppol2tp_seq_start(struct seq_file * m,loff_t * offs)1432 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1433 {
1434 struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1435 loff_t pos = *offs;
1436 struct net *net;
1437
1438 if (!pos)
1439 goto out;
1440
1441 if (WARN_ON(!m->private)) {
1442 pd = NULL;
1443 goto out;
1444 }
1445
1446 pd = m->private;
1447 net = seq_file_net(m);
1448
1449 if (!pd->tunnel)
1450 pppol2tp_next_tunnel(net, pd);
1451 else
1452 pppol2tp_next_session(net, pd);
1453
1454 /* NULL tunnel and session indicates end of list */
1455 if (!pd->tunnel && !pd->session)
1456 pd = NULL;
1457
1458 out:
1459 return pd;
1460 }
1461
pppol2tp_seq_next(struct seq_file * m,void * v,loff_t * pos)1462 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1463 {
1464 (*pos)++;
1465 return NULL;
1466 }
1467
pppol2tp_seq_stop(struct seq_file * p,void * v)1468 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1469 {
1470 struct pppol2tp_seq_data *pd = v;
1471
1472 if (!pd || pd == SEQ_START_TOKEN)
1473 return;
1474
1475 /* Drop reference taken by last invocation of pppol2tp_next_session()
1476 * or pppol2tp_next_tunnel().
1477 */
1478 if (pd->session) {
1479 l2tp_session_put(pd->session);
1480 pd->session = NULL;
1481 }
1482 if (pd->tunnel) {
1483 l2tp_tunnel_put(pd->tunnel);
1484 pd->tunnel = NULL;
1485 }
1486 }
1487
pppol2tp_seq_tunnel_show(struct seq_file * m,void * v)1488 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1489 {
1490 struct l2tp_tunnel *tunnel = v;
1491
1492 seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1493 tunnel->name,
1494 tunnel->sock ? 'Y' : 'N',
1495 refcount_read(&tunnel->ref_count) - 1);
1496 seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1497 0,
1498 atomic_long_read(&tunnel->stats.tx_packets),
1499 atomic_long_read(&tunnel->stats.tx_bytes),
1500 atomic_long_read(&tunnel->stats.tx_errors),
1501 atomic_long_read(&tunnel->stats.rx_packets),
1502 atomic_long_read(&tunnel->stats.rx_bytes),
1503 atomic_long_read(&tunnel->stats.rx_errors));
1504 }
1505
pppol2tp_seq_session_show(struct seq_file * m,void * v)1506 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1507 {
1508 struct l2tp_session *session = v;
1509 struct l2tp_tunnel *tunnel = session->tunnel;
1510 unsigned char state;
1511 char user_data_ok;
1512 struct sock *sk;
1513 u32 ip = 0;
1514 u16 port = 0;
1515
1516 if (tunnel->sock) {
1517 struct inet_sock *inet = inet_sk(tunnel->sock);
1518
1519 ip = ntohl(inet->inet_saddr);
1520 port = ntohs(inet->inet_sport);
1521 }
1522
1523 rcu_read_lock();
1524 sk = pppol2tp_session_get_sock(session);
1525 if (sk) {
1526 state = sk->sk_state;
1527 user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';
1528 } else {
1529 state = 0;
1530 user_data_ok = 'N';
1531 }
1532
1533 seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> %04X/%04X %d %c\n",
1534 session->name, ip, port,
1535 tunnel->tunnel_id,
1536 session->session_id,
1537 tunnel->peer_tunnel_id,
1538 session->peer_session_id,
1539 state, user_data_ok);
1540 seq_printf(m, " 0/0/%c/%c/%s %08x %u\n",
1541 session->recv_seq ? 'R' : '-',
1542 session->send_seq ? 'S' : '-',
1543 session->lns_mode ? "LNS" : "LAC",
1544 0,
1545 jiffies_to_msecs(session->reorder_timeout));
1546 seq_printf(m, " %u/%u %ld/%ld/%ld %ld/%ld/%ld\n",
1547 session->nr, session->ns,
1548 atomic_long_read(&session->stats.tx_packets),
1549 atomic_long_read(&session->stats.tx_bytes),
1550 atomic_long_read(&session->stats.tx_errors),
1551 atomic_long_read(&session->stats.rx_packets),
1552 atomic_long_read(&session->stats.rx_bytes),
1553 atomic_long_read(&session->stats.rx_errors));
1554
1555 if (sk) {
1556 struct pppox_sock *po = pppox_sk(sk);
1557
1558 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
1559 }
1560 rcu_read_unlock();
1561 }
1562
pppol2tp_seq_show(struct seq_file * m,void * v)1563 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1564 {
1565 struct pppol2tp_seq_data *pd = v;
1566
1567 /* display header on line 1 */
1568 if (v == SEQ_START_TOKEN) {
1569 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1570 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1571 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1572 seq_puts(m, " SESSION name, addr/port src-tid/sid dest-tid/sid state user-data-ok\n");
1573 seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1574 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1575 goto out;
1576 }
1577
1578 if (!pd->session)
1579 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1580 else
1581 pppol2tp_seq_session_show(m, pd->session);
1582
1583 out:
1584 return 0;
1585 }
1586
1587 static const struct seq_operations pppol2tp_seq_ops = {
1588 .start = pppol2tp_seq_start,
1589 .next = pppol2tp_seq_next,
1590 .stop = pppol2tp_seq_stop,
1591 .show = pppol2tp_seq_show,
1592 };
1593 #endif /* CONFIG_PROC_FS */
1594
1595 /*****************************************************************************
1596 * Network namespace
1597 *****************************************************************************/
1598
pppol2tp_init_net(struct net * net)1599 static __net_init int pppol2tp_init_net(struct net *net)
1600 {
1601 struct proc_dir_entry *pde;
1602 int err = 0;
1603
1604 pde = proc_create_net("pppol2tp", 0444, net->proc_net,
1605 &pppol2tp_seq_ops, sizeof(struct pppol2tp_seq_data));
1606 if (!pde) {
1607 err = -ENOMEM;
1608 goto out;
1609 }
1610
1611 out:
1612 return err;
1613 }
1614
pppol2tp_exit_net(struct net * net)1615 static __net_exit void pppol2tp_exit_net(struct net *net)
1616 {
1617 remove_proc_entry("pppol2tp", net->proc_net);
1618 }
1619
1620 static struct pernet_operations pppol2tp_net_ops = {
1621 .init = pppol2tp_init_net,
1622 .exit = pppol2tp_exit_net,
1623 };
1624
1625 /*****************************************************************************
1626 * Init and cleanup
1627 *****************************************************************************/
1628
1629 static const struct proto_ops pppol2tp_ops = {
1630 .family = AF_PPPOX,
1631 .owner = THIS_MODULE,
1632 .release = pppol2tp_release,
1633 .bind = sock_no_bind,
1634 .connect = pppol2tp_connect,
1635 .socketpair = sock_no_socketpair,
1636 .accept = sock_no_accept,
1637 .getname = pppol2tp_getname,
1638 .poll = datagram_poll,
1639 .listen = sock_no_listen,
1640 .shutdown = sock_no_shutdown,
1641 .setsockopt = pppol2tp_setsockopt,
1642 .getsockopt = pppol2tp_getsockopt,
1643 .sendmsg = pppol2tp_sendmsg,
1644 .recvmsg = pppol2tp_recvmsg,
1645 .mmap = sock_no_mmap,
1646 .ioctl = pppox_ioctl,
1647 #ifdef CONFIG_COMPAT
1648 .compat_ioctl = pppox_compat_ioctl,
1649 #endif
1650 };
1651
1652 static const struct pppox_proto pppol2tp_proto = {
1653 .create = pppol2tp_create,
1654 .ioctl = pppol2tp_ioctl,
1655 .owner = THIS_MODULE,
1656 };
1657
1658 #ifdef CONFIG_L2TP_V3
1659
1660 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1661 .session_create = pppol2tp_session_create,
1662 .session_delete = l2tp_session_delete,
1663 };
1664
1665 #endif /* CONFIG_L2TP_V3 */
1666
pppol2tp_init(void)1667 static int __init pppol2tp_init(void)
1668 {
1669 int err;
1670
1671 err = register_pernet_device(&pppol2tp_net_ops);
1672 if (err)
1673 goto out;
1674
1675 err = proto_register(&pppol2tp_sk_proto, 0);
1676 if (err)
1677 goto out_unregister_pppol2tp_pernet;
1678
1679 err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1680 if (err)
1681 goto out_unregister_pppol2tp_proto;
1682
1683 #ifdef CONFIG_L2TP_V3
1684 err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1685 if (err)
1686 goto out_unregister_pppox;
1687 #endif
1688
1689 pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1690
1691 out:
1692 return err;
1693
1694 #ifdef CONFIG_L2TP_V3
1695 out_unregister_pppox:
1696 unregister_pppox_proto(PX_PROTO_OL2TP);
1697 #endif
1698 out_unregister_pppol2tp_proto:
1699 proto_unregister(&pppol2tp_sk_proto);
1700 out_unregister_pppol2tp_pernet:
1701 unregister_pernet_device(&pppol2tp_net_ops);
1702 goto out;
1703 }
1704
pppol2tp_exit(void)1705 static void __exit pppol2tp_exit(void)
1706 {
1707 #ifdef CONFIG_L2TP_V3
1708 l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1709 #endif
1710 unregister_pppox_proto(PX_PROTO_OL2TP);
1711 proto_unregister(&pppol2tp_sk_proto);
1712 unregister_pernet_device(&pppol2tp_net_ops);
1713 }
1714
1715 module_init(pppol2tp_init);
1716 module_exit(pppol2tp_exit);
1717
1718 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1719 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1720 MODULE_LICENSE("GPL");
1721 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1722 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OL2TP);
1723 MODULE_ALIAS_L2TP_PWTYPE(7);
1724