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l2tp: ensure session can't get removed during pppol2tp_session_ioctl()
[mirror_ubuntu-bionic-kernel.git] / net / l2tp / l2tp_ppp.c
1 /*****************************************************************************
2 * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
3 *
4 * PPPoX --- Generic PPP encapsulation socket family
5 * PPPoL2TP --- PPP over L2TP (RFC 2661)
6 *
7 * Version: 2.0.0
8 *
9 * Authors: James Chapman (jchapman@katalix.com)
10 *
11 * Based on original work by Martijn van Oosterhout <kleptog@svana.org>
12 *
13 * License:
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
18 *
19 */
20
21 /* This driver handles only L2TP data frames; control frames are handled by a
22 * userspace application.
23 *
24 * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
25 * attaches it to a bound UDP socket with local tunnel_id / session_id and
26 * peer tunnel_id / session_id set. Data can then be sent or received using
27 * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
28 * can be read or modified using ioctl() or [gs]etsockopt() calls.
29 *
30 * When a PPPoL2TP socket is connected with local and peer session_id values
31 * zero, the socket is treated as a special tunnel management socket.
32 *
33 * Here's example userspace code to create a socket for sending/receiving data
34 * over an L2TP session:-
35 *
36 * struct sockaddr_pppol2tp sax;
37 * int fd;
38 * int session_fd;
39 *
40 * fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
41 *
42 * sax.sa_family = AF_PPPOX;
43 * sax.sa_protocol = PX_PROTO_OL2TP;
44 * sax.pppol2tp.fd = tunnel_fd; // bound UDP socket
45 * sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
46 * sax.pppol2tp.addr.sin_port = addr->sin_port;
47 * sax.pppol2tp.addr.sin_family = AF_INET;
48 * sax.pppol2tp.s_tunnel = tunnel_id;
49 * sax.pppol2tp.s_session = session_id;
50 * sax.pppol2tp.d_tunnel = peer_tunnel_id;
51 * sax.pppol2tp.d_session = peer_session_id;
52 *
53 * session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
54 *
55 * A pppd plugin that allows PPP traffic to be carried over L2TP using
56 * this driver is available from the OpenL2TP project at
57 * http://openl2tp.sourceforge.net.
58 */
59
60 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
61
62 #include <linux/module.h>
63 #include <linux/string.h>
64 #include <linux/list.h>
65 #include <linux/uaccess.h>
66
67 #include <linux/kernel.h>
68 #include <linux/spinlock.h>
69 #include <linux/kthread.h>
70 #include <linux/sched.h>
71 #include <linux/slab.h>
72 #include <linux/errno.h>
73 #include <linux/jiffies.h>
74
75 #include <linux/netdevice.h>
76 #include <linux/net.h>
77 #include <linux/inetdevice.h>
78 #include <linux/skbuff.h>
79 #include <linux/init.h>
80 #include <linux/ip.h>
81 #include <linux/udp.h>
82 #include <linux/if_pppox.h>
83 #include <linux/if_pppol2tp.h>
84 #include <net/sock.h>
85 #include <linux/ppp_channel.h>
86 #include <linux/ppp_defs.h>
87 #include <linux/ppp-ioctl.h>
88 #include <linux/file.h>
89 #include <linux/hash.h>
90 #include <linux/sort.h>
91 #include <linux/proc_fs.h>
92 #include <linux/l2tp.h>
93 #include <linux/nsproxy.h>
94 #include <net/net_namespace.h>
95 #include <net/netns/generic.h>
96 #include <net/dst.h>
97 #include <net/ip.h>
98 #include <net/udp.h>
99 #include <net/xfrm.h>
100 #include <net/inet_common.h>
101
102 #include <asm/byteorder.h>
103 #include <linux/atomic.h>
104
105 #include "l2tp_core.h"
106
107 #define PPPOL2TP_DRV_VERSION "V2.0"
108
109 /* Space for UDP, L2TP and PPP headers */
110 #define PPPOL2TP_HEADER_OVERHEAD 40
111
112 /* Number of bytes to build transmit L2TP headers.
113 * Unfortunately the size is different depending on whether sequence numbers
114 * are enabled.
115 */
116 #define PPPOL2TP_L2TP_HDR_SIZE_SEQ 10
117 #define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ 6
118
119 /* Private data of each session. This data lives at the end of struct
120 * l2tp_session, referenced via session->priv[].
121 */
122 struct pppol2tp_session {
123 int owner; /* pid that opened the socket */
124
125 struct sock *sock; /* Pointer to the session
126 * PPPoX socket */
127 struct sock *tunnel_sock; /* Pointer to the tunnel UDP
128 * socket */
129 int flags; /* accessed by PPPIOCGFLAGS.
130 * Unused. */
131 };
132
133 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
134
135 static const struct ppp_channel_ops pppol2tp_chan_ops = {
136 .start_xmit = pppol2tp_xmit,
137 };
138
139 static const struct proto_ops pppol2tp_ops;
140
141 /* Helpers to obtain tunnel/session contexts from sockets.
142 */
143 static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
144 {
145 struct l2tp_session *session;
146
147 if (sk == NULL)
148 return NULL;
149
150 sock_hold(sk);
151 session = (struct l2tp_session *)(sk->sk_user_data);
152 if (session == NULL) {
153 sock_put(sk);
154 goto out;
155 }
156
157 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
158
159 out:
160 return session;
161 }
162
163 /*****************************************************************************
164 * Receive data handling
165 *****************************************************************************/
166
167 static int pppol2tp_recv_payload_hook(struct sk_buff *skb)
168 {
169 /* Skip PPP header, if present. In testing, Microsoft L2TP clients
170 * don't send the PPP header (PPP header compression enabled), but
171 * other clients can include the header. So we cope with both cases
172 * here. The PPP header is always FF03 when using L2TP.
173 *
174 * Note that skb->data[] isn't dereferenced from a u16 ptr here since
175 * the field may be unaligned.
176 */
177 if (!pskb_may_pull(skb, 2))
178 return 1;
179
180 if ((skb->data[0] == PPP_ALLSTATIONS) && (skb->data[1] == PPP_UI))
181 skb_pull(skb, 2);
182
183 return 0;
184 }
185
186 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
187 */
188 static int pppol2tp_recvmsg(struct socket *sock, struct msghdr *msg,
189 size_t len, int flags)
190 {
191 int err;
192 struct sk_buff *skb;
193 struct sock *sk = sock->sk;
194
195 err = -EIO;
196 if (sk->sk_state & PPPOX_BOUND)
197 goto end;
198
199 err = 0;
200 skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
201 flags & MSG_DONTWAIT, &err);
202 if (!skb)
203 goto end;
204
205 if (len > skb->len)
206 len = skb->len;
207 else if (len < skb->len)
208 msg->msg_flags |= MSG_TRUNC;
209
210 err = skb_copy_datagram_msg(skb, 0, msg, len);
211 if (likely(err == 0))
212 err = len;
213
214 kfree_skb(skb);
215 end:
216 return err;
217 }
218
219 static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
220 {
221 struct pppol2tp_session *ps = l2tp_session_priv(session);
222 struct sock *sk = NULL;
223
224 /* If the socket is bound, send it in to PPP's input queue. Otherwise
225 * queue it on the session socket.
226 */
227 sk = ps->sock;
228 if (sk == NULL)
229 goto no_sock;
230
231 if (sk->sk_state & PPPOX_BOUND) {
232 struct pppox_sock *po;
233
234 l2tp_dbg(session, L2TP_MSG_DATA,
235 "%s: recv %d byte data frame, passing to ppp\n",
236 session->name, data_len);
237
238 po = pppox_sk(sk);
239 ppp_input(&po->chan, skb);
240 } else {
241 l2tp_dbg(session, L2TP_MSG_DATA,
242 "%s: recv %d byte data frame, passing to L2TP socket\n",
243 session->name, data_len);
244
245 if (sock_queue_rcv_skb(sk, skb) < 0) {
246 atomic_long_inc(&session->stats.rx_errors);
247 kfree_skb(skb);
248 }
249 }
250
251 return;
252
253 no_sock:
254 l2tp_info(session, L2TP_MSG_DATA, "%s: no socket\n", session->name);
255 kfree_skb(skb);
256 }
257
258 static void pppol2tp_session_sock_hold(struct l2tp_session *session)
259 {
260 struct pppol2tp_session *ps = l2tp_session_priv(session);
261
262 if (ps->sock)
263 sock_hold(ps->sock);
264 }
265
266 static void pppol2tp_session_sock_put(struct l2tp_session *session)
267 {
268 struct pppol2tp_session *ps = l2tp_session_priv(session);
269
270 if (ps->sock)
271 sock_put(ps->sock);
272 }
273
274 /************************************************************************
275 * Transmit handling
276 ***********************************************************************/
277
278 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket. We come here
279 * when a user application does a sendmsg() on the session socket. L2TP and
280 * PPP headers must be inserted into the user's data.
281 */
282 static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
283 size_t total_len)
284 {
285 struct sock *sk = sock->sk;
286 struct sk_buff *skb;
287 int error;
288 struct l2tp_session *session;
289 struct l2tp_tunnel *tunnel;
290 struct pppol2tp_session *ps;
291 int uhlen;
292
293 error = -ENOTCONN;
294 if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
295 goto error;
296
297 /* Get session and tunnel contexts */
298 error = -EBADF;
299 session = pppol2tp_sock_to_session(sk);
300 if (session == NULL)
301 goto error;
302
303 ps = l2tp_session_priv(session);
304 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
305 if (tunnel == NULL)
306 goto error_put_sess;
307
308 uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
309
310 /* Allocate a socket buffer */
311 error = -ENOMEM;
312 skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
313 uhlen + session->hdr_len +
314 2 + total_len, /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
315 0, GFP_KERNEL);
316 if (!skb)
317 goto error_put_sess_tun;
318
319 /* Reserve space for headers. */
320 skb_reserve(skb, NET_SKB_PAD);
321 skb_reset_network_header(skb);
322 skb_reserve(skb, sizeof(struct iphdr));
323 skb_reset_transport_header(skb);
324 skb_reserve(skb, uhlen);
325
326 /* Add PPP header */
327 skb->data[0] = PPP_ALLSTATIONS;
328 skb->data[1] = PPP_UI;
329 skb_put(skb, 2);
330
331 /* Copy user data into skb */
332 error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
333 if (error < 0) {
334 kfree_skb(skb);
335 goto error_put_sess_tun;
336 }
337
338 local_bh_disable();
339 l2tp_xmit_skb(session, skb, session->hdr_len);
340 local_bh_enable();
341
342 sock_put(ps->tunnel_sock);
343 sock_put(sk);
344
345 return total_len;
346
347 error_put_sess_tun:
348 sock_put(ps->tunnel_sock);
349 error_put_sess:
350 sock_put(sk);
351 error:
352 return error;
353 }
354
355 /* Transmit function called by generic PPP driver. Sends PPP frame
356 * over PPPoL2TP socket.
357 *
358 * This is almost the same as pppol2tp_sendmsg(), but rather than
359 * being called with a msghdr from userspace, it is called with a skb
360 * from the kernel.
361 *
362 * The supplied skb from ppp doesn't have enough headroom for the
363 * insertion of L2TP, UDP and IP headers so we need to allocate more
364 * headroom in the skb. This will create a cloned skb. But we must be
365 * careful in the error case because the caller will expect to free
366 * the skb it supplied, not our cloned skb. So we take care to always
367 * leave the original skb unfreed if we return an error.
368 */
369 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
370 {
371 struct sock *sk = (struct sock *) chan->private;
372 struct sock *sk_tun;
373 struct l2tp_session *session;
374 struct l2tp_tunnel *tunnel;
375 struct pppol2tp_session *ps;
376 int uhlen, headroom;
377
378 if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
379 goto abort;
380
381 /* Get session and tunnel contexts from the socket */
382 session = pppol2tp_sock_to_session(sk);
383 if (session == NULL)
384 goto abort;
385
386 ps = l2tp_session_priv(session);
387 sk_tun = ps->tunnel_sock;
388 if (sk_tun == NULL)
389 goto abort_put_sess;
390 tunnel = l2tp_sock_to_tunnel(sk_tun);
391 if (tunnel == NULL)
392 goto abort_put_sess;
393
394 uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
395 headroom = NET_SKB_PAD +
396 sizeof(struct iphdr) + /* IP header */
397 uhlen + /* UDP header (if L2TP_ENCAPTYPE_UDP) */
398 session->hdr_len + /* L2TP header */
399 2; /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
400 if (skb_cow_head(skb, headroom))
401 goto abort_put_sess_tun;
402
403 /* Setup PPP header */
404 __skb_push(skb, 2);
405 skb->data[0] = PPP_ALLSTATIONS;
406 skb->data[1] = PPP_UI;
407
408 local_bh_disable();
409 l2tp_xmit_skb(session, skb, session->hdr_len);
410 local_bh_enable();
411
412 sock_put(sk_tun);
413 sock_put(sk);
414 return 1;
415
416 abort_put_sess_tun:
417 sock_put(sk_tun);
418 abort_put_sess:
419 sock_put(sk);
420 abort:
421 /* Free the original skb */
422 kfree_skb(skb);
423 return 1;
424 }
425
426 /*****************************************************************************
427 * Session (and tunnel control) socket create/destroy.
428 *****************************************************************************/
429
430 /* Called by l2tp_core when a session socket is being closed.
431 */
432 static void pppol2tp_session_close(struct l2tp_session *session)
433 {
434 struct pppol2tp_session *ps = l2tp_session_priv(session);
435 struct sock *sk = ps->sock;
436 struct socket *sock = sk->sk_socket;
437
438 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
439
440 if (sock) {
441 inet_shutdown(sock, SEND_SHUTDOWN);
442 /* Don't let the session go away before our socket does */
443 l2tp_session_inc_refcount(session);
444 }
445 }
446
447 /* Really kill the session socket. (Called from sock_put() if
448 * refcnt == 0.)
449 */
450 static void pppol2tp_session_destruct(struct sock *sk)
451 {
452 struct l2tp_session *session = sk->sk_user_data;
453
454 skb_queue_purge(&sk->sk_receive_queue);
455 skb_queue_purge(&sk->sk_write_queue);
456
457 if (session) {
458 sk->sk_user_data = NULL;
459 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
460 l2tp_session_dec_refcount(session);
461 }
462 }
463
464 /* Called when the PPPoX socket (session) is closed.
465 */
466 static int pppol2tp_release(struct socket *sock)
467 {
468 struct sock *sk = sock->sk;
469 struct l2tp_session *session;
470 int error;
471
472 if (!sk)
473 return 0;
474
475 error = -EBADF;
476 lock_sock(sk);
477 if (sock_flag(sk, SOCK_DEAD) != 0)
478 goto error;
479
480 pppox_unbind_sock(sk);
481
482 /* Signal the death of the socket. */
483 sk->sk_state = PPPOX_DEAD;
484 sock_orphan(sk);
485 sock->sk = NULL;
486
487 session = pppol2tp_sock_to_session(sk);
488
489 /* Purge any queued data */
490 if (session != NULL) {
491 __l2tp_session_unhash(session);
492 l2tp_session_queue_purge(session);
493 sock_put(sk);
494 }
495 release_sock(sk);
496
497 /* This will delete the session context via
498 * pppol2tp_session_destruct() if the socket's refcnt drops to
499 * zero.
500 */
501 sock_put(sk);
502
503 return 0;
504
505 error:
506 release_sock(sk);
507 return error;
508 }
509
510 static struct proto pppol2tp_sk_proto = {
511 .name = "PPPOL2TP",
512 .owner = THIS_MODULE,
513 .obj_size = sizeof(struct pppox_sock),
514 };
515
516 static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
517 {
518 int rc;
519
520 rc = l2tp_udp_encap_recv(sk, skb);
521 if (rc)
522 kfree_skb(skb);
523
524 return NET_RX_SUCCESS;
525 }
526
527 /* socket() handler. Initialize a new struct sock.
528 */
529 static int pppol2tp_create(struct net *net, struct socket *sock, int kern)
530 {
531 int error = -ENOMEM;
532 struct sock *sk;
533
534 sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto, kern);
535 if (!sk)
536 goto out;
537
538 sock_init_data(sock, sk);
539
540 sock->state = SS_UNCONNECTED;
541 sock->ops = &pppol2tp_ops;
542
543 sk->sk_backlog_rcv = pppol2tp_backlog_recv;
544 sk->sk_protocol = PX_PROTO_OL2TP;
545 sk->sk_family = PF_PPPOX;
546 sk->sk_state = PPPOX_NONE;
547 sk->sk_type = SOCK_STREAM;
548 sk->sk_destruct = pppol2tp_session_destruct;
549
550 error = 0;
551
552 out:
553 return error;
554 }
555
556 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
557 static void pppol2tp_show(struct seq_file *m, void *arg)
558 {
559 struct l2tp_session *session = arg;
560 struct pppol2tp_session *ps = l2tp_session_priv(session);
561
562 if (ps) {
563 struct pppox_sock *po = pppox_sk(ps->sock);
564 if (po)
565 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
566 }
567 }
568 #endif
569
570 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
571 */
572 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
573 int sockaddr_len, int flags)
574 {
575 struct sock *sk = sock->sk;
576 struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
577 struct pppox_sock *po = pppox_sk(sk);
578 struct l2tp_session *session = NULL;
579 struct l2tp_tunnel *tunnel;
580 struct pppol2tp_session *ps;
581 struct dst_entry *dst;
582 struct l2tp_session_cfg cfg = { 0, };
583 int error = 0;
584 u32 tunnel_id, peer_tunnel_id;
585 u32 session_id, peer_session_id;
586 int ver = 2;
587 int fd;
588
589 lock_sock(sk);
590
591 error = -EINVAL;
592 if (sp->sa_protocol != PX_PROTO_OL2TP)
593 goto end;
594
595 /* Check for already bound sockets */
596 error = -EBUSY;
597 if (sk->sk_state & PPPOX_CONNECTED)
598 goto end;
599
600 /* We don't supporting rebinding anyway */
601 error = -EALREADY;
602 if (sk->sk_user_data)
603 goto end; /* socket is already attached */
604
605 /* Get params from socket address. Handle L2TPv2 and L2TPv3.
606 * This is nasty because there are different sockaddr_pppol2tp
607 * structs for L2TPv2, L2TPv3, over IPv4 and IPv6. We use
608 * the sockaddr size to determine which structure the caller
609 * is using.
610 */
611 peer_tunnel_id = 0;
612 if (sockaddr_len == sizeof(struct sockaddr_pppol2tp)) {
613 fd = sp->pppol2tp.fd;
614 tunnel_id = sp->pppol2tp.s_tunnel;
615 peer_tunnel_id = sp->pppol2tp.d_tunnel;
616 session_id = sp->pppol2tp.s_session;
617 peer_session_id = sp->pppol2tp.d_session;
618 } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3)) {
619 struct sockaddr_pppol2tpv3 *sp3 =
620 (struct sockaddr_pppol2tpv3 *) sp;
621 ver = 3;
622 fd = sp3->pppol2tp.fd;
623 tunnel_id = sp3->pppol2tp.s_tunnel;
624 peer_tunnel_id = sp3->pppol2tp.d_tunnel;
625 session_id = sp3->pppol2tp.s_session;
626 peer_session_id = sp3->pppol2tp.d_session;
627 } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpin6)) {
628 struct sockaddr_pppol2tpin6 *sp6 =
629 (struct sockaddr_pppol2tpin6 *) sp;
630 fd = sp6->pppol2tp.fd;
631 tunnel_id = sp6->pppol2tp.s_tunnel;
632 peer_tunnel_id = sp6->pppol2tp.d_tunnel;
633 session_id = sp6->pppol2tp.s_session;
634 peer_session_id = sp6->pppol2tp.d_session;
635 } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3in6)) {
636 struct sockaddr_pppol2tpv3in6 *sp6 =
637 (struct sockaddr_pppol2tpv3in6 *) sp;
638 ver = 3;
639 fd = sp6->pppol2tp.fd;
640 tunnel_id = sp6->pppol2tp.s_tunnel;
641 peer_tunnel_id = sp6->pppol2tp.d_tunnel;
642 session_id = sp6->pppol2tp.s_session;
643 peer_session_id = sp6->pppol2tp.d_session;
644 } else {
645 error = -EINVAL;
646 goto end; /* bad socket address */
647 }
648
649 /* Don't bind if tunnel_id is 0 */
650 error = -EINVAL;
651 if (tunnel_id == 0)
652 goto end;
653
654 tunnel = l2tp_tunnel_find(sock_net(sk), tunnel_id);
655
656 /* Special case: create tunnel context if session_id and
657 * peer_session_id is 0. Otherwise look up tunnel using supplied
658 * tunnel id.
659 */
660 if ((session_id == 0) && (peer_session_id == 0)) {
661 if (tunnel == NULL) {
662 struct l2tp_tunnel_cfg tcfg = {
663 .encap = L2TP_ENCAPTYPE_UDP,
664 .debug = 0,
665 };
666 error = l2tp_tunnel_create(sock_net(sk), fd, ver, tunnel_id, peer_tunnel_id, &tcfg, &tunnel);
667 if (error < 0)
668 goto end;
669 }
670 } else {
671 /* Error if we can't find the tunnel */
672 error = -ENOENT;
673 if (tunnel == NULL)
674 goto end;
675
676 /* Error if socket is not prepped */
677 if (tunnel->sock == NULL)
678 goto end;
679 }
680
681 if (tunnel->recv_payload_hook == NULL)
682 tunnel->recv_payload_hook = pppol2tp_recv_payload_hook;
683
684 if (tunnel->peer_tunnel_id == 0)
685 tunnel->peer_tunnel_id = peer_tunnel_id;
686
687 /* Create session if it doesn't already exist. We handle the
688 * case where a session was previously created by the netlink
689 * interface by checking that the session doesn't already have
690 * a socket and its tunnel socket are what we expect. If any
691 * of those checks fail, return EEXIST to the caller.
692 */
693 session = l2tp_session_find(sock_net(sk), tunnel, session_id);
694 if (session == NULL) {
695 /* Default MTU must allow space for UDP/L2TP/PPP
696 * headers.
697 */
698 cfg.mtu = cfg.mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
699
700 /* Allocate and initialize a new session context. */
701 session = l2tp_session_create(sizeof(struct pppol2tp_session),
702 tunnel, session_id,
703 peer_session_id, &cfg);
704 if (session == NULL) {
705 error = -ENOMEM;
706 goto end;
707 }
708 } else {
709 ps = l2tp_session_priv(session);
710 error = -EEXIST;
711 if (ps->sock != NULL)
712 goto end;
713
714 /* consistency checks */
715 if (ps->tunnel_sock != tunnel->sock)
716 goto end;
717 }
718
719 /* Associate session with its PPPoL2TP socket */
720 ps = l2tp_session_priv(session);
721 ps->owner = current->pid;
722 ps->sock = sk;
723 ps->tunnel_sock = tunnel->sock;
724
725 session->recv_skb = pppol2tp_recv;
726 session->session_close = pppol2tp_session_close;
727 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
728 session->show = pppol2tp_show;
729 #endif
730
731 /* We need to know each time a skb is dropped from the reorder
732 * queue.
733 */
734 session->ref = pppol2tp_session_sock_hold;
735 session->deref = pppol2tp_session_sock_put;
736
737 /* If PMTU discovery was enabled, use the MTU that was discovered */
738 dst = sk_dst_get(tunnel->sock);
739 if (dst != NULL) {
740 u32 pmtu = dst_mtu(dst);
741
742 if (pmtu != 0)
743 session->mtu = session->mru = pmtu -
744 PPPOL2TP_HEADER_OVERHEAD;
745 dst_release(dst);
746 }
747
748 /* Special case: if source & dest session_id == 0x0000, this
749 * socket is being created to manage the tunnel. Just set up
750 * the internal context for use by ioctl() and sockopt()
751 * handlers.
752 */
753 if ((session->session_id == 0) &&
754 (session->peer_session_id == 0)) {
755 error = 0;
756 goto out_no_ppp;
757 }
758
759 /* The only header we need to worry about is the L2TP
760 * header. This size is different depending on whether
761 * sequence numbers are enabled for the data channel.
762 */
763 po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
764
765 po->chan.private = sk;
766 po->chan.ops = &pppol2tp_chan_ops;
767 po->chan.mtu = session->mtu;
768
769 error = ppp_register_net_channel(sock_net(sk), &po->chan);
770 if (error)
771 goto end;
772
773 out_no_ppp:
774 /* This is how we get the session context from the socket. */
775 sk->sk_user_data = session;
776 sk->sk_state = PPPOX_CONNECTED;
777 l2tp_info(session, L2TP_MSG_CONTROL, "%s: created\n",
778 session->name);
779
780 end:
781 release_sock(sk);
782
783 return error;
784 }
785
786 #ifdef CONFIG_L2TP_V3
787
788 /* Called when creating sessions via the netlink interface.
789 */
790 static int pppol2tp_session_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
791 {
792 int error;
793 struct l2tp_tunnel *tunnel;
794 struct l2tp_session *session;
795 struct pppol2tp_session *ps;
796
797 tunnel = l2tp_tunnel_find(net, tunnel_id);
798
799 /* Error if we can't find the tunnel */
800 error = -ENOENT;
801 if (tunnel == NULL)
802 goto out;
803
804 /* Error if tunnel socket is not prepped */
805 if (tunnel->sock == NULL)
806 goto out;
807
808 /* Check that this session doesn't already exist */
809 error = -EEXIST;
810 session = l2tp_session_find(net, tunnel, session_id);
811 if (session != NULL)
812 goto out;
813
814 /* Default MTU values. */
815 if (cfg->mtu == 0)
816 cfg->mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
817 if (cfg->mru == 0)
818 cfg->mru = cfg->mtu;
819
820 /* Allocate and initialize a new session context. */
821 error = -ENOMEM;
822 session = l2tp_session_create(sizeof(struct pppol2tp_session),
823 tunnel, session_id,
824 peer_session_id, cfg);
825 if (session == NULL)
826 goto out;
827
828 ps = l2tp_session_priv(session);
829 ps->tunnel_sock = tunnel->sock;
830
831 l2tp_info(session, L2TP_MSG_CONTROL, "%s: created\n",
832 session->name);
833
834 error = 0;
835
836 out:
837 return error;
838 }
839
840 #endif /* CONFIG_L2TP_V3 */
841
842 /* getname() support.
843 */
844 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
845 int *usockaddr_len, int peer)
846 {
847 int len = 0;
848 int error = 0;
849 struct l2tp_session *session;
850 struct l2tp_tunnel *tunnel;
851 struct sock *sk = sock->sk;
852 struct inet_sock *inet;
853 struct pppol2tp_session *pls;
854
855 error = -ENOTCONN;
856 if (sk == NULL)
857 goto end;
858 if (!(sk->sk_state & PPPOX_CONNECTED))
859 goto end;
860
861 error = -EBADF;
862 session = pppol2tp_sock_to_session(sk);
863 if (session == NULL)
864 goto end;
865
866 pls = l2tp_session_priv(session);
867 tunnel = l2tp_sock_to_tunnel(pls->tunnel_sock);
868 if (tunnel == NULL)
869 goto end_put_sess;
870
871 inet = inet_sk(tunnel->sock);
872 if ((tunnel->version == 2) && (tunnel->sock->sk_family == AF_INET)) {
873 struct sockaddr_pppol2tp sp;
874 len = sizeof(sp);
875 memset(&sp, 0, len);
876 sp.sa_family = AF_PPPOX;
877 sp.sa_protocol = PX_PROTO_OL2TP;
878 sp.pppol2tp.fd = tunnel->fd;
879 sp.pppol2tp.pid = pls->owner;
880 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
881 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
882 sp.pppol2tp.s_session = session->session_id;
883 sp.pppol2tp.d_session = session->peer_session_id;
884 sp.pppol2tp.addr.sin_family = AF_INET;
885 sp.pppol2tp.addr.sin_port = inet->inet_dport;
886 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
887 memcpy(uaddr, &sp, len);
888 #if IS_ENABLED(CONFIG_IPV6)
889 } else if ((tunnel->version == 2) &&
890 (tunnel->sock->sk_family == AF_INET6)) {
891 struct sockaddr_pppol2tpin6 sp;
892
893 len = sizeof(sp);
894 memset(&sp, 0, len);
895 sp.sa_family = AF_PPPOX;
896 sp.sa_protocol = PX_PROTO_OL2TP;
897 sp.pppol2tp.fd = tunnel->fd;
898 sp.pppol2tp.pid = pls->owner;
899 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
900 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
901 sp.pppol2tp.s_session = session->session_id;
902 sp.pppol2tp.d_session = session->peer_session_id;
903 sp.pppol2tp.addr.sin6_family = AF_INET6;
904 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
905 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
906 sizeof(tunnel->sock->sk_v6_daddr));
907 memcpy(uaddr, &sp, len);
908 } else if ((tunnel->version == 3) &&
909 (tunnel->sock->sk_family == AF_INET6)) {
910 struct sockaddr_pppol2tpv3in6 sp;
911
912 len = sizeof(sp);
913 memset(&sp, 0, len);
914 sp.sa_family = AF_PPPOX;
915 sp.sa_protocol = PX_PROTO_OL2TP;
916 sp.pppol2tp.fd = tunnel->fd;
917 sp.pppol2tp.pid = pls->owner;
918 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
919 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
920 sp.pppol2tp.s_session = session->session_id;
921 sp.pppol2tp.d_session = session->peer_session_id;
922 sp.pppol2tp.addr.sin6_family = AF_INET6;
923 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
924 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
925 sizeof(tunnel->sock->sk_v6_daddr));
926 memcpy(uaddr, &sp, len);
927 #endif
928 } else if (tunnel->version == 3) {
929 struct sockaddr_pppol2tpv3 sp;
930 len = sizeof(sp);
931 memset(&sp, 0, len);
932 sp.sa_family = AF_PPPOX;
933 sp.sa_protocol = PX_PROTO_OL2TP;
934 sp.pppol2tp.fd = tunnel->fd;
935 sp.pppol2tp.pid = pls->owner;
936 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
937 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
938 sp.pppol2tp.s_session = session->session_id;
939 sp.pppol2tp.d_session = session->peer_session_id;
940 sp.pppol2tp.addr.sin_family = AF_INET;
941 sp.pppol2tp.addr.sin_port = inet->inet_dport;
942 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
943 memcpy(uaddr, &sp, len);
944 }
945
946 *usockaddr_len = len;
947 error = 0;
948
949 sock_put(pls->tunnel_sock);
950 end_put_sess:
951 sock_put(sk);
952 end:
953 return error;
954 }
955
956 /****************************************************************************
957 * ioctl() handlers.
958 *
959 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
960 * sockets. However, in order to control kernel tunnel features, we allow
961 * userspace to create a special "tunnel" PPPoX socket which is used for
962 * control only. Tunnel PPPoX sockets have session_id == 0 and simply allow
963 * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
964 * calls.
965 ****************************************************************************/
966
967 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
968 struct l2tp_stats *stats)
969 {
970 dest->tx_packets = atomic_long_read(&stats->tx_packets);
971 dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
972 dest->tx_errors = atomic_long_read(&stats->tx_errors);
973 dest->rx_packets = atomic_long_read(&stats->rx_packets);
974 dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
975 dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
976 dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
977 dest->rx_errors = atomic_long_read(&stats->rx_errors);
978 }
979
980 /* Session ioctl helper.
981 */
982 static int pppol2tp_session_ioctl(struct l2tp_session *session,
983 unsigned int cmd, unsigned long arg)
984 {
985 struct ifreq ifr;
986 int err = 0;
987 struct sock *sk;
988 int val = (int) arg;
989 struct pppol2tp_session *ps = l2tp_session_priv(session);
990 struct l2tp_tunnel *tunnel = session->tunnel;
991 struct pppol2tp_ioc_stats stats;
992
993 l2tp_dbg(session, L2TP_MSG_CONTROL,
994 "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
995 session->name, cmd, arg);
996
997 sk = ps->sock;
998 sock_hold(sk);
999
1000 switch (cmd) {
1001 case SIOCGIFMTU:
1002 err = -ENXIO;
1003 if (!(sk->sk_state & PPPOX_CONNECTED))
1004 break;
1005
1006 err = -EFAULT;
1007 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1008 break;
1009 ifr.ifr_mtu = session->mtu;
1010 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1011 break;
1012
1013 l2tp_info(session, L2TP_MSG_CONTROL, "%s: get mtu=%d\n",
1014 session->name, session->mtu);
1015 err = 0;
1016 break;
1017
1018 case SIOCSIFMTU:
1019 err = -ENXIO;
1020 if (!(sk->sk_state & PPPOX_CONNECTED))
1021 break;
1022
1023 err = -EFAULT;
1024 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1025 break;
1026
1027 session->mtu = ifr.ifr_mtu;
1028
1029 l2tp_info(session, L2TP_MSG_CONTROL, "%s: set mtu=%d\n",
1030 session->name, session->mtu);
1031 err = 0;
1032 break;
1033
1034 case PPPIOCGMRU:
1035 err = -ENXIO;
1036 if (!(sk->sk_state & PPPOX_CONNECTED))
1037 break;
1038
1039 err = -EFAULT;
1040 if (put_user(session->mru, (int __user *) arg))
1041 break;
1042
1043 l2tp_info(session, L2TP_MSG_CONTROL, "%s: get mru=%d\n",
1044 session->name, session->mru);
1045 err = 0;
1046 break;
1047
1048 case PPPIOCSMRU:
1049 err = -ENXIO;
1050 if (!(sk->sk_state & PPPOX_CONNECTED))
1051 break;
1052
1053 err = -EFAULT;
1054 if (get_user(val, (int __user *) arg))
1055 break;
1056
1057 session->mru = val;
1058 l2tp_info(session, L2TP_MSG_CONTROL, "%s: set mru=%d\n",
1059 session->name, session->mru);
1060 err = 0;
1061 break;
1062
1063 case PPPIOCGFLAGS:
1064 err = -EFAULT;
1065 if (put_user(ps->flags, (int __user *) arg))
1066 break;
1067
1068 l2tp_info(session, L2TP_MSG_CONTROL, "%s: get flags=%d\n",
1069 session->name, ps->flags);
1070 err = 0;
1071 break;
1072
1073 case PPPIOCSFLAGS:
1074 err = -EFAULT;
1075 if (get_user(val, (int __user *) arg))
1076 break;
1077 ps->flags = val;
1078 l2tp_info(session, L2TP_MSG_CONTROL, "%s: set flags=%d\n",
1079 session->name, ps->flags);
1080 err = 0;
1081 break;
1082
1083 case PPPIOCGL2TPSTATS:
1084 err = -ENXIO;
1085 if (!(sk->sk_state & PPPOX_CONNECTED))
1086 break;
1087
1088 memset(&stats, 0, sizeof(stats));
1089 stats.tunnel_id = tunnel->tunnel_id;
1090 stats.session_id = session->session_id;
1091 pppol2tp_copy_stats(&stats, &session->stats);
1092 if (copy_to_user((void __user *) arg, &stats,
1093 sizeof(stats)))
1094 break;
1095 l2tp_info(session, L2TP_MSG_CONTROL, "%s: get L2TP stats\n",
1096 session->name);
1097 err = 0;
1098 break;
1099
1100 default:
1101 err = -ENOSYS;
1102 break;
1103 }
1104
1105 sock_put(sk);
1106
1107 return err;
1108 }
1109
1110 /* Tunnel ioctl helper.
1111 *
1112 * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1113 * specifies a session_id, the session ioctl handler is called. This allows an
1114 * application to retrieve session stats via a tunnel socket.
1115 */
1116 static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
1117 unsigned int cmd, unsigned long arg)
1118 {
1119 int err = 0;
1120 struct sock *sk;
1121 struct pppol2tp_ioc_stats stats;
1122
1123 l2tp_dbg(tunnel, L2TP_MSG_CONTROL,
1124 "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n",
1125 tunnel->name, cmd, arg);
1126
1127 sk = tunnel->sock;
1128 sock_hold(sk);
1129
1130 switch (cmd) {
1131 case PPPIOCGL2TPSTATS:
1132 err = -ENXIO;
1133 if (!(sk->sk_state & PPPOX_CONNECTED))
1134 break;
1135
1136 if (copy_from_user(&stats, (void __user *) arg,
1137 sizeof(stats))) {
1138 err = -EFAULT;
1139 break;
1140 }
1141 if (stats.session_id != 0) {
1142 /* resend to session ioctl handler */
1143 struct l2tp_session *session =
1144 l2tp_session_get(sock_net(sk), tunnel,
1145 stats.session_id, true);
1146
1147 if (session) {
1148 err = pppol2tp_session_ioctl(session, cmd,
1149 arg);
1150 if (session->deref)
1151 session->deref(session);
1152 l2tp_session_dec_refcount(session);
1153 } else {
1154 err = -EBADR;
1155 }
1156 break;
1157 }
1158 #ifdef CONFIG_XFRM
1159 stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
1160 #endif
1161 pppol2tp_copy_stats(&stats, &tunnel->stats);
1162 if (copy_to_user((void __user *) arg, &stats, sizeof(stats))) {
1163 err = -EFAULT;
1164 break;
1165 }
1166 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: get L2TP stats\n",
1167 tunnel->name);
1168 err = 0;
1169 break;
1170
1171 default:
1172 err = -ENOSYS;
1173 break;
1174 }
1175
1176 sock_put(sk);
1177
1178 return err;
1179 }
1180
1181 /* Main ioctl() handler.
1182 * Dispatch to tunnel or session helpers depending on the socket.
1183 */
1184 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1185 unsigned long arg)
1186 {
1187 struct sock *sk = sock->sk;
1188 struct l2tp_session *session;
1189 struct l2tp_tunnel *tunnel;
1190 struct pppol2tp_session *ps;
1191 int err;
1192
1193 if (!sk)
1194 return 0;
1195
1196 err = -EBADF;
1197 if (sock_flag(sk, SOCK_DEAD) != 0)
1198 goto end;
1199
1200 err = -ENOTCONN;
1201 if ((sk->sk_user_data == NULL) ||
1202 (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
1203 goto end;
1204
1205 /* Get session context from the socket */
1206 err = -EBADF;
1207 session = pppol2tp_sock_to_session(sk);
1208 if (session == NULL)
1209 goto end;
1210
1211 /* Special case: if session's session_id is zero, treat ioctl as a
1212 * tunnel ioctl
1213 */
1214 ps = l2tp_session_priv(session);
1215 if ((session->session_id == 0) &&
1216 (session->peer_session_id == 0)) {
1217 err = -EBADF;
1218 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1219 if (tunnel == NULL)
1220 goto end_put_sess;
1221
1222 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
1223 sock_put(ps->tunnel_sock);
1224 goto end_put_sess;
1225 }
1226
1227 err = pppol2tp_session_ioctl(session, cmd, arg);
1228
1229 end_put_sess:
1230 sock_put(sk);
1231 end:
1232 return err;
1233 }
1234
1235 /*****************************************************************************
1236 * setsockopt() / getsockopt() support.
1237 *
1238 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1239 * sockets. In order to control kernel tunnel features, we allow userspace to
1240 * create a special "tunnel" PPPoX socket which is used for control only.
1241 * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1242 * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1243 *****************************************************************************/
1244
1245 /* Tunnel setsockopt() helper.
1246 */
1247 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1248 struct l2tp_tunnel *tunnel,
1249 int optname, int val)
1250 {
1251 int err = 0;
1252
1253 switch (optname) {
1254 case PPPOL2TP_SO_DEBUG:
1255 tunnel->debug = val;
1256 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: set debug=%x\n",
1257 tunnel->name, tunnel->debug);
1258 break;
1259
1260 default:
1261 err = -ENOPROTOOPT;
1262 break;
1263 }
1264
1265 return err;
1266 }
1267
1268 /* Session setsockopt helper.
1269 */
1270 static int pppol2tp_session_setsockopt(struct sock *sk,
1271 struct l2tp_session *session,
1272 int optname, int val)
1273 {
1274 int err = 0;
1275 struct pppol2tp_session *ps = l2tp_session_priv(session);
1276
1277 switch (optname) {
1278 case PPPOL2TP_SO_RECVSEQ:
1279 if ((val != 0) && (val != 1)) {
1280 err = -EINVAL;
1281 break;
1282 }
1283 session->recv_seq = !!val;
1284 l2tp_info(session, L2TP_MSG_CONTROL,
1285 "%s: set recv_seq=%d\n",
1286 session->name, session->recv_seq);
1287 break;
1288
1289 case PPPOL2TP_SO_SENDSEQ:
1290 if ((val != 0) && (val != 1)) {
1291 err = -EINVAL;
1292 break;
1293 }
1294 session->send_seq = !!val;
1295 {
1296 struct sock *ssk = ps->sock;
1297 struct pppox_sock *po = pppox_sk(ssk);
1298 po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1299 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1300 }
1301 l2tp_session_set_header_len(session, session->tunnel->version);
1302 l2tp_info(session, L2TP_MSG_CONTROL,
1303 "%s: set send_seq=%d\n",
1304 session->name, session->send_seq);
1305 break;
1306
1307 case PPPOL2TP_SO_LNSMODE:
1308 if ((val != 0) && (val != 1)) {
1309 err = -EINVAL;
1310 break;
1311 }
1312 session->lns_mode = !!val;
1313 l2tp_info(session, L2TP_MSG_CONTROL,
1314 "%s: set lns_mode=%d\n",
1315 session->name, session->lns_mode);
1316 break;
1317
1318 case PPPOL2TP_SO_DEBUG:
1319 session->debug = val;
1320 l2tp_info(session, L2TP_MSG_CONTROL, "%s: set debug=%x\n",
1321 session->name, session->debug);
1322 break;
1323
1324 case PPPOL2TP_SO_REORDERTO:
1325 session->reorder_timeout = msecs_to_jiffies(val);
1326 l2tp_info(session, L2TP_MSG_CONTROL,
1327 "%s: set reorder_timeout=%d\n",
1328 session->name, session->reorder_timeout);
1329 break;
1330
1331 default:
1332 err = -ENOPROTOOPT;
1333 break;
1334 }
1335
1336 return err;
1337 }
1338
1339 /* Main setsockopt() entry point.
1340 * Does API checks, then calls either the tunnel or session setsockopt
1341 * handler, according to whether the PPPoL2TP socket is a for a regular
1342 * session or the special tunnel type.
1343 */
1344 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1345 char __user *optval, unsigned int optlen)
1346 {
1347 struct sock *sk = sock->sk;
1348 struct l2tp_session *session;
1349 struct l2tp_tunnel *tunnel;
1350 struct pppol2tp_session *ps;
1351 int val;
1352 int err;
1353
1354 if (level != SOL_PPPOL2TP)
1355 return -EINVAL;
1356
1357 if (optlen < sizeof(int))
1358 return -EINVAL;
1359
1360 if (get_user(val, (int __user *)optval))
1361 return -EFAULT;
1362
1363 err = -ENOTCONN;
1364 if (sk->sk_user_data == NULL)
1365 goto end;
1366
1367 /* Get session context from the socket */
1368 err = -EBADF;
1369 session = pppol2tp_sock_to_session(sk);
1370 if (session == NULL)
1371 goto end;
1372
1373 /* Special case: if session_id == 0x0000, treat as operation on tunnel
1374 */
1375 ps = l2tp_session_priv(session);
1376 if ((session->session_id == 0) &&
1377 (session->peer_session_id == 0)) {
1378 err = -EBADF;
1379 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1380 if (tunnel == NULL)
1381 goto end_put_sess;
1382
1383 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1384 sock_put(ps->tunnel_sock);
1385 } else
1386 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1387
1388 err = 0;
1389
1390 end_put_sess:
1391 sock_put(sk);
1392 end:
1393 return err;
1394 }
1395
1396 /* Tunnel getsockopt helper. Called with sock locked.
1397 */
1398 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1399 struct l2tp_tunnel *tunnel,
1400 int optname, int *val)
1401 {
1402 int err = 0;
1403
1404 switch (optname) {
1405 case PPPOL2TP_SO_DEBUG:
1406 *val = tunnel->debug;
1407 l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: get debug=%x\n",
1408 tunnel->name, tunnel->debug);
1409 break;
1410
1411 default:
1412 err = -ENOPROTOOPT;
1413 break;
1414 }
1415
1416 return err;
1417 }
1418
1419 /* Session getsockopt helper. Called with sock locked.
1420 */
1421 static int pppol2tp_session_getsockopt(struct sock *sk,
1422 struct l2tp_session *session,
1423 int optname, int *val)
1424 {
1425 int err = 0;
1426
1427 switch (optname) {
1428 case PPPOL2TP_SO_RECVSEQ:
1429 *val = session->recv_seq;
1430 l2tp_info(session, L2TP_MSG_CONTROL,
1431 "%s: get recv_seq=%d\n", session->name, *val);
1432 break;
1433
1434 case PPPOL2TP_SO_SENDSEQ:
1435 *val = session->send_seq;
1436 l2tp_info(session, L2TP_MSG_CONTROL,
1437 "%s: get send_seq=%d\n", session->name, *val);
1438 break;
1439
1440 case PPPOL2TP_SO_LNSMODE:
1441 *val = session->lns_mode;
1442 l2tp_info(session, L2TP_MSG_CONTROL,
1443 "%s: get lns_mode=%d\n", session->name, *val);
1444 break;
1445
1446 case PPPOL2TP_SO_DEBUG:
1447 *val = session->debug;
1448 l2tp_info(session, L2TP_MSG_CONTROL, "%s: get debug=%d\n",
1449 session->name, *val);
1450 break;
1451
1452 case PPPOL2TP_SO_REORDERTO:
1453 *val = (int) jiffies_to_msecs(session->reorder_timeout);
1454 l2tp_info(session, L2TP_MSG_CONTROL,
1455 "%s: get reorder_timeout=%d\n", session->name, *val);
1456 break;
1457
1458 default:
1459 err = -ENOPROTOOPT;
1460 }
1461
1462 return err;
1463 }
1464
1465 /* Main getsockopt() entry point.
1466 * Does API checks, then calls either the tunnel or session getsockopt
1467 * handler, according to whether the PPPoX socket is a for a regular session
1468 * or the special tunnel type.
1469 */
1470 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1471 char __user *optval, int __user *optlen)
1472 {
1473 struct sock *sk = sock->sk;
1474 struct l2tp_session *session;
1475 struct l2tp_tunnel *tunnel;
1476 int val, len;
1477 int err;
1478 struct pppol2tp_session *ps;
1479
1480 if (level != SOL_PPPOL2TP)
1481 return -EINVAL;
1482
1483 if (get_user(len, optlen))
1484 return -EFAULT;
1485
1486 len = min_t(unsigned int, len, sizeof(int));
1487
1488 if (len < 0)
1489 return -EINVAL;
1490
1491 err = -ENOTCONN;
1492 if (sk->sk_user_data == NULL)
1493 goto end;
1494
1495 /* Get the session context */
1496 err = -EBADF;
1497 session = pppol2tp_sock_to_session(sk);
1498 if (session == NULL)
1499 goto end;
1500
1501 /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1502 ps = l2tp_session_priv(session);
1503 if ((session->session_id == 0) &&
1504 (session->peer_session_id == 0)) {
1505 err = -EBADF;
1506 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1507 if (tunnel == NULL)
1508 goto end_put_sess;
1509
1510 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1511 sock_put(ps->tunnel_sock);
1512 } else
1513 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1514
1515 err = -EFAULT;
1516 if (put_user(len, optlen))
1517 goto end_put_sess;
1518
1519 if (copy_to_user((void __user *) optval, &val, len))
1520 goto end_put_sess;
1521
1522 err = 0;
1523
1524 end_put_sess:
1525 sock_put(sk);
1526 end:
1527 return err;
1528 }
1529
1530 /*****************************************************************************
1531 * /proc filesystem for debug
1532 * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1533 * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1534 *****************************************************************************/
1535
1536 static unsigned int pppol2tp_net_id;
1537
1538 #ifdef CONFIG_PROC_FS
1539
1540 struct pppol2tp_seq_data {
1541 struct seq_net_private p;
1542 int tunnel_idx; /* current tunnel */
1543 int session_idx; /* index of session within current tunnel */
1544 struct l2tp_tunnel *tunnel;
1545 struct l2tp_session *session; /* NULL means get next tunnel */
1546 };
1547
1548 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1549 {
1550 for (;;) {
1551 pd->tunnel = l2tp_tunnel_find_nth(net, pd->tunnel_idx);
1552 pd->tunnel_idx++;
1553
1554 if (pd->tunnel == NULL)
1555 break;
1556
1557 /* Ignore L2TPv3 tunnels */
1558 if (pd->tunnel->version < 3)
1559 break;
1560 }
1561 }
1562
1563 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1564 {
1565 pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
1566 pd->session_idx++;
1567
1568 if (pd->session == NULL) {
1569 pd->session_idx = 0;
1570 pppol2tp_next_tunnel(net, pd);
1571 }
1572 }
1573
1574 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1575 {
1576 struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1577 loff_t pos = *offs;
1578 struct net *net;
1579
1580 if (!pos)
1581 goto out;
1582
1583 BUG_ON(m->private == NULL);
1584 pd = m->private;
1585 net = seq_file_net(m);
1586
1587 if (pd->tunnel == NULL)
1588 pppol2tp_next_tunnel(net, pd);
1589 else
1590 pppol2tp_next_session(net, pd);
1591
1592 /* NULL tunnel and session indicates end of list */
1593 if ((pd->tunnel == NULL) && (pd->session == NULL))
1594 pd = NULL;
1595
1596 out:
1597 return pd;
1598 }
1599
1600 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1601 {
1602 (*pos)++;
1603 return NULL;
1604 }
1605
1606 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1607 {
1608 /* nothing to do */
1609 }
1610
1611 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1612 {
1613 struct l2tp_tunnel *tunnel = v;
1614
1615 seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1616 tunnel->name,
1617 (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N',
1618 atomic_read(&tunnel->ref_count) - 1);
1619 seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1620 tunnel->debug,
1621 atomic_long_read(&tunnel->stats.tx_packets),
1622 atomic_long_read(&tunnel->stats.tx_bytes),
1623 atomic_long_read(&tunnel->stats.tx_errors),
1624 atomic_long_read(&tunnel->stats.rx_packets),
1625 atomic_long_read(&tunnel->stats.rx_bytes),
1626 atomic_long_read(&tunnel->stats.rx_errors));
1627 }
1628
1629 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1630 {
1631 struct l2tp_session *session = v;
1632 struct l2tp_tunnel *tunnel = session->tunnel;
1633 struct pppol2tp_session *ps = l2tp_session_priv(session);
1634 struct pppox_sock *po = pppox_sk(ps->sock);
1635 u32 ip = 0;
1636 u16 port = 0;
1637
1638 if (tunnel->sock) {
1639 struct inet_sock *inet = inet_sk(tunnel->sock);
1640 ip = ntohl(inet->inet_saddr);
1641 port = ntohs(inet->inet_sport);
1642 }
1643
1644 seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> "
1645 "%04X/%04X %d %c\n",
1646 session->name, ip, port,
1647 tunnel->tunnel_id,
1648 session->session_id,
1649 tunnel->peer_tunnel_id,
1650 session->peer_session_id,
1651 ps->sock->sk_state,
1652 (session == ps->sock->sk_user_data) ?
1653 'Y' : 'N');
1654 seq_printf(m, " %d/%d/%c/%c/%s %08x %u\n",
1655 session->mtu, session->mru,
1656 session->recv_seq ? 'R' : '-',
1657 session->send_seq ? 'S' : '-',
1658 session->lns_mode ? "LNS" : "LAC",
1659 session->debug,
1660 jiffies_to_msecs(session->reorder_timeout));
1661 seq_printf(m, " %hu/%hu %ld/%ld/%ld %ld/%ld/%ld\n",
1662 session->nr, session->ns,
1663 atomic_long_read(&session->stats.tx_packets),
1664 atomic_long_read(&session->stats.tx_bytes),
1665 atomic_long_read(&session->stats.tx_errors),
1666 atomic_long_read(&session->stats.rx_packets),
1667 atomic_long_read(&session->stats.rx_bytes),
1668 atomic_long_read(&session->stats.rx_errors));
1669
1670 if (po)
1671 seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
1672 }
1673
1674 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1675 {
1676 struct pppol2tp_seq_data *pd = v;
1677
1678 /* display header on line 1 */
1679 if (v == SEQ_START_TOKEN) {
1680 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1681 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1682 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1683 seq_puts(m, " SESSION name, addr/port src-tid/sid "
1684 "dest-tid/sid state user-data-ok\n");
1685 seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1686 seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1687 goto out;
1688 }
1689
1690 /* Show the tunnel or session context.
1691 */
1692 if (pd->session == NULL)
1693 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1694 else
1695 pppol2tp_seq_session_show(m, pd->session);
1696
1697 out:
1698 return 0;
1699 }
1700
1701 static const struct seq_operations pppol2tp_seq_ops = {
1702 .start = pppol2tp_seq_start,
1703 .next = pppol2tp_seq_next,
1704 .stop = pppol2tp_seq_stop,
1705 .show = pppol2tp_seq_show,
1706 };
1707
1708 /* Called when our /proc file is opened. We allocate data for use when
1709 * iterating our tunnel / session contexts and store it in the private
1710 * data of the seq_file.
1711 */
1712 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
1713 {
1714 return seq_open_net(inode, file, &pppol2tp_seq_ops,
1715 sizeof(struct pppol2tp_seq_data));
1716 }
1717
1718 static const struct file_operations pppol2tp_proc_fops = {
1719 .owner = THIS_MODULE,
1720 .open = pppol2tp_proc_open,
1721 .read = seq_read,
1722 .llseek = seq_lseek,
1723 .release = seq_release_net,
1724 };
1725
1726 #endif /* CONFIG_PROC_FS */
1727
1728 /*****************************************************************************
1729 * Network namespace
1730 *****************************************************************************/
1731
1732 static __net_init int pppol2tp_init_net(struct net *net)
1733 {
1734 struct proc_dir_entry *pde;
1735 int err = 0;
1736
1737 pde = proc_create("pppol2tp", S_IRUGO, net->proc_net,
1738 &pppol2tp_proc_fops);
1739 if (!pde) {
1740 err = -ENOMEM;
1741 goto out;
1742 }
1743
1744 out:
1745 return err;
1746 }
1747
1748 static __net_exit void pppol2tp_exit_net(struct net *net)
1749 {
1750 remove_proc_entry("pppol2tp", net->proc_net);
1751 }
1752
1753 static struct pernet_operations pppol2tp_net_ops = {
1754 .init = pppol2tp_init_net,
1755 .exit = pppol2tp_exit_net,
1756 .id = &pppol2tp_net_id,
1757 };
1758
1759 /*****************************************************************************
1760 * Init and cleanup
1761 *****************************************************************************/
1762
1763 static const struct proto_ops pppol2tp_ops = {
1764 .family = AF_PPPOX,
1765 .owner = THIS_MODULE,
1766 .release = pppol2tp_release,
1767 .bind = sock_no_bind,
1768 .connect = pppol2tp_connect,
1769 .socketpair = sock_no_socketpair,
1770 .accept = sock_no_accept,
1771 .getname = pppol2tp_getname,
1772 .poll = datagram_poll,
1773 .listen = sock_no_listen,
1774 .shutdown = sock_no_shutdown,
1775 .setsockopt = pppol2tp_setsockopt,
1776 .getsockopt = pppol2tp_getsockopt,
1777 .sendmsg = pppol2tp_sendmsg,
1778 .recvmsg = pppol2tp_recvmsg,
1779 .mmap = sock_no_mmap,
1780 .ioctl = pppox_ioctl,
1781 };
1782
1783 static const struct pppox_proto pppol2tp_proto = {
1784 .create = pppol2tp_create,
1785 .ioctl = pppol2tp_ioctl,
1786 .owner = THIS_MODULE,
1787 };
1788
1789 #ifdef CONFIG_L2TP_V3
1790
1791 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1792 .session_create = pppol2tp_session_create,
1793 .session_delete = l2tp_session_delete,
1794 };
1795
1796 #endif /* CONFIG_L2TP_V3 */
1797
1798 static int __init pppol2tp_init(void)
1799 {
1800 int err;
1801
1802 err = register_pernet_device(&pppol2tp_net_ops);
1803 if (err)
1804 goto out;
1805
1806 err = proto_register(&pppol2tp_sk_proto, 0);
1807 if (err)
1808 goto out_unregister_pppol2tp_pernet;
1809
1810 err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1811 if (err)
1812 goto out_unregister_pppol2tp_proto;
1813
1814 #ifdef CONFIG_L2TP_V3
1815 err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1816 if (err)
1817 goto out_unregister_pppox;
1818 #endif
1819
1820 pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1821
1822 out:
1823 return err;
1824
1825 #ifdef CONFIG_L2TP_V3
1826 out_unregister_pppox:
1827 unregister_pppox_proto(PX_PROTO_OL2TP);
1828 #endif
1829 out_unregister_pppol2tp_proto:
1830 proto_unregister(&pppol2tp_sk_proto);
1831 out_unregister_pppol2tp_pernet:
1832 unregister_pernet_device(&pppol2tp_net_ops);
1833 goto out;
1834 }
1835
1836 static void __exit pppol2tp_exit(void)
1837 {
1838 #ifdef CONFIG_L2TP_V3
1839 l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1840 #endif
1841 unregister_pppox_proto(PX_PROTO_OL2TP);
1842 proto_unregister(&pppol2tp_sk_proto);
1843 unregister_pernet_device(&pppol2tp_net_ops);
1844 }
1845
1846 module_init(pppol2tp_init);
1847 module_exit(pppol2tp_exit);
1848
1849 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1850 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1851 MODULE_LICENSE("GPL");
1852 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1853 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OL2TP);
1854 MODULE_ALIAS_L2TP_PWTYPE(11);
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