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TOMOYO Linux Cross Reference
Linux/net/l2tp/l2tp_ppp.c

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  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] == 0xff) && (skb->data[1] == 0x03))
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, PPPOL2TP_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, PPPOL2TP_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, PPPOL2TP_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         static const unsigned char ppph[2] = { 0xff, 0x03 };
286         struct sock *sk = sock->sk;
287         struct sk_buff *skb;
288         int error;
289         struct l2tp_session *session;
290         struct l2tp_tunnel *tunnel;
291         struct pppol2tp_session *ps;
292         int uhlen;
293 
294         error = -ENOTCONN;
295         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
296                 goto error;
297 
298         /* Get session and tunnel contexts */
299         error = -EBADF;
300         session = pppol2tp_sock_to_session(sk);
301         if (session == NULL)
302                 goto error;
303 
304         ps = l2tp_session_priv(session);
305         tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
306         if (tunnel == NULL)
307                 goto error_put_sess;
308 
309         uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
310 
311         /* Allocate a socket buffer */
312         error = -ENOMEM;
313         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
314                            uhlen + session->hdr_len +
315                            sizeof(ppph) + total_len,
316                            0, GFP_KERNEL);
317         if (!skb)
318                 goto error_put_sess_tun;
319 
320         /* Reserve space for headers. */
321         skb_reserve(skb, NET_SKB_PAD);
322         skb_reset_network_header(skb);
323         skb_reserve(skb, sizeof(struct iphdr));
324         skb_reset_transport_header(skb);
325         skb_reserve(skb, uhlen);
326 
327         /* Add PPP header */
328         skb->data[0] = ppph[0];
329         skb->data[1] = ppph[1];
330         skb_put(skb, 2);
331 
332         /* Copy user data into skb */
333         error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
334         if (error < 0) {
335                 kfree_skb(skb);
336                 goto error_put_sess_tun;
337         }
338 
339         local_bh_disable();
340         l2tp_xmit_skb(session, skb, session->hdr_len);
341         local_bh_enable();
342 
343         sock_put(ps->tunnel_sock);
344         sock_put(sk);
345 
346         return total_len;
347 
348 error_put_sess_tun:
349         sock_put(ps->tunnel_sock);
350 error_put_sess:
351         sock_put(sk);
352 error:
353         return error;
354 }
355 
356 /* Transmit function called by generic PPP driver.  Sends PPP frame
357  * over PPPoL2TP socket.
358  *
359  * This is almost the same as pppol2tp_sendmsg(), but rather than
360  * being called with a msghdr from userspace, it is called with a skb
361  * from the kernel.
362  *
363  * The supplied skb from ppp doesn't have enough headroom for the
364  * insertion of L2TP, UDP and IP headers so we need to allocate more
365  * headroom in the skb. This will create a cloned skb. But we must be
366  * careful in the error case because the caller will expect to free
367  * the skb it supplied, not our cloned skb. So we take care to always
368  * leave the original skb unfreed if we return an error.
369  */
370 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
371 {
372         static const u8 ppph[2] = { 0xff, 0x03 };
373         struct sock *sk = (struct sock *) chan->private;
374         struct sock *sk_tun;
375         struct l2tp_session *session;
376         struct l2tp_tunnel *tunnel;
377         struct pppol2tp_session *ps;
378         int uhlen, headroom;
379 
380         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
381                 goto abort;
382 
383         /* Get session and tunnel contexts from the socket */
384         session = pppol2tp_sock_to_session(sk);
385         if (session == NULL)
386                 goto abort;
387 
388         ps = l2tp_session_priv(session);
389         sk_tun = ps->tunnel_sock;
390         if (sk_tun == NULL)
391                 goto abort_put_sess;
392         tunnel = l2tp_sock_to_tunnel(sk_tun);
393         if (tunnel == NULL)
394                 goto abort_put_sess;
395 
396         uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
397         headroom = NET_SKB_PAD +
398                    sizeof(struct iphdr) + /* IP header */
399                    uhlen +              /* UDP header (if L2TP_ENCAPTYPE_UDP) */
400                    session->hdr_len +   /* L2TP header */
401                    sizeof(ppph);        /* PPP header */
402         if (skb_cow_head(skb, headroom))
403                 goto abort_put_sess_tun;
404 
405         /* Setup PPP header */
406         __skb_push(skb, sizeof(ppph));
407         skb->data[0] = ppph[0];
408         skb->data[1] = ppph[1];
409 
410         local_bh_disable();
411         l2tp_xmit_skb(session, skb, session->hdr_len);
412         local_bh_enable();
413 
414         sock_put(sk_tun);
415         sock_put(sk);
416         return 1;
417 
418 abort_put_sess_tun:
419         sock_put(sk_tun);
420 abort_put_sess:
421         sock_put(sk);
422 abort:
423         /* Free the original skb */
424         kfree_skb(skb);
425         return 1;
426 }
427 
428 /*****************************************************************************
429  * Session (and tunnel control) socket create/destroy.
430  *****************************************************************************/
431 
432 /* Called by l2tp_core when a session socket is being closed.
433  */
434 static void pppol2tp_session_close(struct l2tp_session *session)
435 {
436         struct pppol2tp_session *ps = l2tp_session_priv(session);
437         struct sock *sk = ps->sock;
438         struct socket *sock = sk->sk_socket;
439 
440         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
441 
442         if (sock) {
443                 inet_shutdown(sock, 2);
444                 /* Don't let the session go away before our socket does */
445                 l2tp_session_inc_refcount(session);
446         }
447 }
448 
449 /* Really kill the session socket. (Called from sock_put() if
450  * refcnt == 0.)
451  */
452 static void pppol2tp_session_destruct(struct sock *sk)
453 {
454         struct l2tp_session *session = sk->sk_user_data;
455         if (session) {
456                 sk->sk_user_data = NULL;
457                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
458                 l2tp_session_dec_refcount(session);
459         }
460 }
461 
462 /* Called when the PPPoX socket (session) is closed.
463  */
464 static int pppol2tp_release(struct socket *sock)
465 {
466         struct sock *sk = sock->sk;
467         struct l2tp_session *session;
468         int error;
469 
470         if (!sk)
471                 return 0;
472 
473         error = -EBADF;
474         lock_sock(sk);
475         if (sock_flag(sk, SOCK_DEAD) != 0)
476                 goto error;
477 
478         pppox_unbind_sock(sk);
479 
480         /* Signal the death of the socket. */
481         sk->sk_state = PPPOX_DEAD;
482         sock_orphan(sk);
483         sock->sk = NULL;
484 
485         session = pppol2tp_sock_to_session(sk);
486 
487         /* Purge any queued data */
488         if (session != NULL) {
489                 __l2tp_session_unhash(session);
490                 l2tp_session_queue_purge(session);
491                 sock_put(sk);
492         }
493         skb_queue_purge(&sk->sk_receive_queue);
494         skb_queue_purge(&sk->sk_write_queue);
495 
496         release_sock(sk);
497 
498         /* This will delete the session context via
499          * pppol2tp_session_destruct() if the socket's refcnt drops to
500          * zero.
501          */
502         sock_put(sk);
503 
504         return 0;
505 
506 error:
507         release_sock(sk);
508         return error;
509 }
510 
511 static struct proto pppol2tp_sk_proto = {
512         .name     = "PPPOL2TP",
513         .owner    = THIS_MODULE,
514         .obj_size = sizeof(struct pppox_sock),
515 };
516 
517 static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
518 {
519         int rc;
520 
521         rc = l2tp_udp_encap_recv(sk, skb);
522         if (rc)
523                 kfree_skb(skb);
524 
525         return NET_RX_SUCCESS;
526 }
527 
528 /* socket() handler. Initialize a new struct sock.
529  */
530 static int pppol2tp_create(struct net *net, struct socket *sock, int kern)
531 {
532         int error = -ENOMEM;
533         struct sock *sk;
534 
535         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto, kern);
536         if (!sk)
537                 goto out;
538 
539         sock_init_data(sock, sk);
540 
541         sock->state  = SS_UNCONNECTED;
542         sock->ops    = &pppol2tp_ops;
543 
544         sk->sk_backlog_rcv = pppol2tp_backlog_recv;
545         sk->sk_protocol    = PX_PROTO_OL2TP;
546         sk->sk_family      = PF_PPPOX;
547         sk->sk_state       = PPPOX_NONE;
548         sk->sk_type        = SOCK_STREAM;
549         sk->sk_destruct    = pppol2tp_session_destruct;
550 
551         error = 0;
552 
553 out:
554         return error;
555 }
556 
557 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
558 static void pppol2tp_show(struct seq_file *m, void *arg)
559 {
560         struct l2tp_session *session = arg;
561         struct pppol2tp_session *ps = l2tp_session_priv(session);
562 
563         if (ps) {
564                 struct pppox_sock *po = pppox_sk(ps->sock);
565                 if (po)
566                         seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
567         }
568 }
569 #endif
570 
571 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
572  */
573 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
574                             int sockaddr_len, int flags)
575 {
576         struct sock *sk = sock->sk;
577         struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
578         struct pppox_sock *po = pppox_sk(sk);
579         struct l2tp_session *session = NULL;
580         struct l2tp_tunnel *tunnel;
581         struct pppol2tp_session *ps;
582         struct dst_entry *dst;
583         struct l2tp_session_cfg cfg = { 0, };
584         int error = 0;
585         u32 tunnel_id, peer_tunnel_id;
586         u32 session_id, peer_session_id;
587         int ver = 2;
588         int fd;
589 
590         lock_sock(sk);
591 
592         error = -EINVAL;
593         if (sp->sa_protocol != PX_PROTO_OL2TP)
594                 goto end;
595 
596         /* Check for already bound sockets */
597         error = -EBUSY;
598         if (sk->sk_state & PPPOX_CONNECTED)
599                 goto end;
600 
601         /* We don't supporting rebinding anyway */
602         error = -EALREADY;
603         if (sk->sk_user_data)
604                 goto end; /* socket is already attached */
605 
606         /* Get params from socket address. Handle L2TPv2 and L2TPv3.
607          * This is nasty because there are different sockaddr_pppol2tp
608          * structs for L2TPv2, L2TPv3, over IPv4 and IPv6. We use
609          * the sockaddr size to determine which structure the caller
610          * is using.
611          */
612         peer_tunnel_id = 0;
613         if (sockaddr_len == sizeof(struct sockaddr_pppol2tp)) {
614                 fd = sp->pppol2tp.fd;
615                 tunnel_id = sp->pppol2tp.s_tunnel;
616                 peer_tunnel_id = sp->pppol2tp.d_tunnel;
617                 session_id = sp->pppol2tp.s_session;
618                 peer_session_id = sp->pppol2tp.d_session;
619         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3)) {
620                 struct sockaddr_pppol2tpv3 *sp3 =
621                         (struct sockaddr_pppol2tpv3 *) sp;
622                 ver = 3;
623                 fd = sp3->pppol2tp.fd;
624                 tunnel_id = sp3->pppol2tp.s_tunnel;
625                 peer_tunnel_id = sp3->pppol2tp.d_tunnel;
626                 session_id = sp3->pppol2tp.s_session;
627                 peer_session_id = sp3->pppol2tp.d_session;
628         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpin6)) {
629                 struct sockaddr_pppol2tpin6 *sp6 =
630                         (struct sockaddr_pppol2tpin6 *) sp;
631                 fd = sp6->pppol2tp.fd;
632                 tunnel_id = sp6->pppol2tp.s_tunnel;
633                 peer_tunnel_id = sp6->pppol2tp.d_tunnel;
634                 session_id = sp6->pppol2tp.s_session;
635                 peer_session_id = sp6->pppol2tp.d_session;
636         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3in6)) {
637                 struct sockaddr_pppol2tpv3in6 *sp6 =
638                         (struct sockaddr_pppol2tpv3in6 *) sp;
639                 ver = 3;
640                 fd = sp6->pppol2tp.fd;
641                 tunnel_id = sp6->pppol2tp.s_tunnel;
642                 peer_tunnel_id = sp6->pppol2tp.d_tunnel;
643                 session_id = sp6->pppol2tp.s_session;
644                 peer_session_id = sp6->pppol2tp.d_session;
645         } else {
646                 error = -EINVAL;
647                 goto end; /* bad socket address */
648         }
649 
650         /* Don't bind if tunnel_id is 0 */
651         error = -EINVAL;
652         if (tunnel_id == 0)
653                 goto end;
654 
655         tunnel = l2tp_tunnel_find(sock_net(sk), tunnel_id);
656 
657         /* Special case: create tunnel context if session_id and
658          * peer_session_id is 0. Otherwise look up tunnel using supplied
659          * tunnel id.
660          */
661         if ((session_id == 0) && (peer_session_id == 0)) {
662                 if (tunnel == NULL) {
663                         struct l2tp_tunnel_cfg tcfg = {
664                                 .encap = L2TP_ENCAPTYPE_UDP,
665                                 .debug = 0,
666                         };
667                         error = l2tp_tunnel_create(sock_net(sk), fd, ver, tunnel_id, peer_tunnel_id, &tcfg, &tunnel);
668                         if (error < 0)
669                                 goto end;
670                 }
671         } else {
672                 /* Error if we can't find the tunnel */
673                 error = -ENOENT;
674                 if (tunnel == NULL)
675                         goto end;
676 
677                 /* Error if socket is not prepped */
678                 if (tunnel->sock == NULL)
679                         goto end;
680         }
681 
682         if (tunnel->recv_payload_hook == NULL)
683                 tunnel->recv_payload_hook = pppol2tp_recv_payload_hook;
684 
685         if (tunnel->peer_tunnel_id == 0)
686                 tunnel->peer_tunnel_id = peer_tunnel_id;
687 
688         /* Create session if it doesn't already exist. We handle the
689          * case where a session was previously created by the netlink
690          * interface by checking that the session doesn't already have
691          * a socket and its tunnel socket are what we expect. If any
692          * of those checks fail, return EEXIST to the caller.
693          */
694         session = l2tp_session_find(sock_net(sk), tunnel, session_id);
695         if (session == NULL) {
696                 /* Default MTU must allow space for UDP/L2TP/PPP
697                  * headers.
698                  */
699                 cfg.mtu = cfg.mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
700 
701                 /* Allocate and initialize a new session context. */
702                 session = l2tp_session_create(sizeof(struct pppol2tp_session),
703                                               tunnel, session_id,
704                                               peer_session_id, &cfg);
705                 if (session == NULL) {
706                         error = -ENOMEM;
707                         goto end;
708                 }
709         } else {
710                 ps = l2tp_session_priv(session);
711                 error = -EEXIST;
712                 if (ps->sock != NULL)
713                         goto end;
714 
715                 /* consistency checks */
716                 if (ps->tunnel_sock != tunnel->sock)
717                         goto end;
718         }
719 
720         /* Associate session with its PPPoL2TP socket */
721         ps = l2tp_session_priv(session);
722         ps->owner            = current->pid;
723         ps->sock             = sk;
724         ps->tunnel_sock = tunnel->sock;
725 
726         session->recv_skb       = pppol2tp_recv;
727         session->session_close  = pppol2tp_session_close;
728 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
729         session->show           = pppol2tp_show;
730 #endif
731 
732         /* We need to know each time a skb is dropped from the reorder
733          * queue.
734          */
735         session->ref = pppol2tp_session_sock_hold;
736         session->deref = pppol2tp_session_sock_put;
737 
738         /* If PMTU discovery was enabled, use the MTU that was discovered */
739         dst = sk_dst_get(tunnel->sock);
740         if (dst != NULL) {
741                 u32 pmtu = dst_mtu(dst);
742 
743                 if (pmtu != 0)
744                         session->mtu = session->mru = pmtu -
745                                 PPPOL2TP_HEADER_OVERHEAD;
746                 dst_release(dst);
747         }
748 
749         /* Special case: if source & dest session_id == 0x0000, this
750          * socket is being created to manage the tunnel. Just set up
751          * the internal context for use by ioctl() and sockopt()
752          * handlers.
753          */
754         if ((session->session_id == 0) &&
755             (session->peer_session_id == 0)) {
756                 error = 0;
757                 goto out_no_ppp;
758         }
759 
760         /* The only header we need to worry about is the L2TP
761          * header. This size is different depending on whether
762          * sequence numbers are enabled for the data channel.
763          */
764         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
765 
766         po->chan.private = sk;
767         po->chan.ops     = &pppol2tp_chan_ops;
768         po->chan.mtu     = session->mtu;
769 
770         error = ppp_register_net_channel(sock_net(sk), &po->chan);
771         if (error)
772                 goto end;
773 
774 out_no_ppp:
775         /* This is how we get the session context from the socket. */
776         sk->sk_user_data = session;
777         sk->sk_state = PPPOX_CONNECTED;
778         l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: created\n",
779                   session->name);
780 
781 end:
782         release_sock(sk);
783 
784         return error;
785 }
786 
787 #ifdef CONFIG_L2TP_V3
788 
789 /* Called when creating sessions via the netlink interface.
790  */
791 static int pppol2tp_session_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
792 {
793         int error;
794         struct l2tp_tunnel *tunnel;
795         struct l2tp_session *session;
796         struct pppol2tp_session *ps;
797 
798         tunnel = l2tp_tunnel_find(net, tunnel_id);
799 
800         /* Error if we can't find the tunnel */
801         error = -ENOENT;
802         if (tunnel == NULL)
803                 goto out;
804 
805         /* Error if tunnel socket is not prepped */
806         if (tunnel->sock == NULL)
807                 goto out;
808 
809         /* Check that this session doesn't already exist */
810         error = -EEXIST;
811         session = l2tp_session_find(net, tunnel, session_id);
812         if (session != NULL)
813                 goto out;
814 
815         /* Default MTU values. */
816         if (cfg->mtu == 0)
817                 cfg->mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
818         if (cfg->mru == 0)
819                 cfg->mru = cfg->mtu;
820 
821         /* Allocate and initialize a new session context. */
822         error = -ENOMEM;
823         session = l2tp_session_create(sizeof(struct pppol2tp_session),
824                                       tunnel, session_id,
825                                       peer_session_id, cfg);
826         if (session == NULL)
827                 goto out;
828 
829         ps = l2tp_session_priv(session);
830         ps->tunnel_sock = tunnel->sock;
831 
832         l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: created\n",
833                   session->name);
834 
835         error = 0;
836 
837 out:
838         return error;
839 }
840 
841 #endif /* CONFIG_L2TP_V3 */
842 
843 /* getname() support.
844  */
845 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
846                             int *usockaddr_len, int peer)
847 {
848         int len = 0;
849         int error = 0;
850         struct l2tp_session *session;
851         struct l2tp_tunnel *tunnel;
852         struct sock *sk = sock->sk;
853         struct inet_sock *inet;
854         struct pppol2tp_session *pls;
855 
856         error = -ENOTCONN;
857         if (sk == NULL)
858                 goto end;
859         if (sk->sk_state != PPPOX_CONNECTED)
860                 goto end;
861 
862         error = -EBADF;
863         session = pppol2tp_sock_to_session(sk);
864         if (session == NULL)
865                 goto end;
866 
867         pls = l2tp_session_priv(session);
868         tunnel = l2tp_sock_to_tunnel(pls->tunnel_sock);
869         if (tunnel == NULL) {
870                 error = -EBADF;
871                 goto end_put_sess;
872         }
873 
874         inet = inet_sk(tunnel->sock);
875         if ((tunnel->version == 2) && (tunnel->sock->sk_family == AF_INET)) {
876                 struct sockaddr_pppol2tp sp;
877                 len = sizeof(sp);
878                 memset(&sp, 0, len);
879                 sp.sa_family    = AF_PPPOX;
880                 sp.sa_protocol  = PX_PROTO_OL2TP;
881                 sp.pppol2tp.fd  = tunnel->fd;
882                 sp.pppol2tp.pid = pls->owner;
883                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
884                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
885                 sp.pppol2tp.s_session = session->session_id;
886                 sp.pppol2tp.d_session = session->peer_session_id;
887                 sp.pppol2tp.addr.sin_family = AF_INET;
888                 sp.pppol2tp.addr.sin_port = inet->inet_dport;
889                 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
890                 memcpy(uaddr, &sp, len);
891 #if IS_ENABLED(CONFIG_IPV6)
892         } else if ((tunnel->version == 2) &&
893                    (tunnel->sock->sk_family == AF_INET6)) {
894                 struct sockaddr_pppol2tpin6 sp;
895 
896                 len = sizeof(sp);
897                 memset(&sp, 0, len);
898                 sp.sa_family    = AF_PPPOX;
899                 sp.sa_protocol  = PX_PROTO_OL2TP;
900                 sp.pppol2tp.fd  = tunnel->fd;
901                 sp.pppol2tp.pid = pls->owner;
902                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
903                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
904                 sp.pppol2tp.s_session = session->session_id;
905                 sp.pppol2tp.d_session = session->peer_session_id;
906                 sp.pppol2tp.addr.sin6_family = AF_INET6;
907                 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
908                 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
909                        sizeof(tunnel->sock->sk_v6_daddr));
910                 memcpy(uaddr, &sp, len);
911         } else if ((tunnel->version == 3) &&
912                    (tunnel->sock->sk_family == AF_INET6)) {
913                 struct sockaddr_pppol2tpv3in6 sp;
914 
915                 len = sizeof(sp);
916                 memset(&sp, 0, len);
917                 sp.sa_family    = AF_PPPOX;
918                 sp.sa_protocol  = PX_PROTO_OL2TP;
919                 sp.pppol2tp.fd  = tunnel->fd;
920                 sp.pppol2tp.pid = pls->owner;
921                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
922                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
923                 sp.pppol2tp.s_session = session->session_id;
924                 sp.pppol2tp.d_session = session->peer_session_id;
925                 sp.pppol2tp.addr.sin6_family = AF_INET6;
926                 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
927                 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
928                        sizeof(tunnel->sock->sk_v6_daddr));
929                 memcpy(uaddr, &sp, len);
930 #endif
931         } else if (tunnel->version == 3) {
932                 struct sockaddr_pppol2tpv3 sp;
933                 len = sizeof(sp);
934                 memset(&sp, 0, len);
935                 sp.sa_family    = AF_PPPOX;
936                 sp.sa_protocol  = PX_PROTO_OL2TP;
937                 sp.pppol2tp.fd  = tunnel->fd;
938                 sp.pppol2tp.pid = pls->owner;
939                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
940                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
941                 sp.pppol2tp.s_session = session->session_id;
942                 sp.pppol2tp.d_session = session->peer_session_id;
943                 sp.pppol2tp.addr.sin_family = AF_INET;
944                 sp.pppol2tp.addr.sin_port = inet->inet_dport;
945                 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
946                 memcpy(uaddr, &sp, len);
947         }
948 
949         *usockaddr_len = len;
950 
951         sock_put(pls->tunnel_sock);
952 end_put_sess:
953         sock_put(sk);
954         error = 0;
955 
956 end:
957         return error;
958 }
959 
960 /****************************************************************************
961  * ioctl() handlers.
962  *
963  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
964  * sockets. However, in order to control kernel tunnel features, we allow
965  * userspace to create a special "tunnel" PPPoX socket which is used for
966  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
967  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
968  * calls.
969  ****************************************************************************/
970 
971 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
972                                 struct l2tp_stats *stats)
973 {
974         dest->tx_packets = atomic_long_read(&stats->tx_packets);
975         dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
976         dest->tx_errors = atomic_long_read(&stats->tx_errors);
977         dest->rx_packets = atomic_long_read(&stats->rx_packets);
978         dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
979         dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
980         dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
981         dest->rx_errors = atomic_long_read(&stats->rx_errors);
982 }
983 
984 /* Session ioctl helper.
985  */
986 static int pppol2tp_session_ioctl(struct l2tp_session *session,
987                                   unsigned int cmd, unsigned long arg)
988 {
989         struct ifreq ifr;
990         int err = 0;
991         struct sock *sk;
992         int val = (int) arg;
993         struct pppol2tp_session *ps = l2tp_session_priv(session);
994         struct l2tp_tunnel *tunnel = session->tunnel;
995         struct pppol2tp_ioc_stats stats;
996 
997         l2tp_dbg(session, PPPOL2TP_MSG_CONTROL,
998                  "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
999                  session->name, cmd, arg);
1000 
1001         sk = ps->sock;
1002         sock_hold(sk);
1003 
1004         switch (cmd) {
1005         case SIOCGIFMTU:
1006                 err = -ENXIO;
1007                 if (!(sk->sk_state & PPPOX_CONNECTED))
1008                         break;
1009 
1010                 err = -EFAULT;
1011                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1012                         break;
1013                 ifr.ifr_mtu = session->mtu;
1014                 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1015                         break;
1016 
1017                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get mtu=%d\n",
1018                           session->name, session->mtu);
1019                 err = 0;
1020                 break;
1021 
1022         case SIOCSIFMTU:
1023                 err = -ENXIO;
1024                 if (!(sk->sk_state & PPPOX_CONNECTED))
1025                         break;
1026 
1027                 err = -EFAULT;
1028                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1029                         break;
1030 
1031                 session->mtu = ifr.ifr_mtu;
1032 
1033                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set mtu=%d\n",
1034                           session->name, session->mtu);
1035                 err = 0;
1036                 break;
1037 
1038         case PPPIOCGMRU:
1039                 err = -ENXIO;
1040                 if (!(sk->sk_state & PPPOX_CONNECTED))
1041                         break;
1042 
1043                 err = -EFAULT;
1044                 if (put_user(session->mru, (int __user *) arg))
1045                         break;
1046 
1047                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get mru=%d\n",
1048                           session->name, session->mru);
1049                 err = 0;
1050                 break;
1051 
1052         case PPPIOCSMRU:
1053                 err = -ENXIO;
1054                 if (!(sk->sk_state & PPPOX_CONNECTED))
1055                         break;
1056 
1057                 err = -EFAULT;
1058                 if (get_user(val, (int __user *) arg))
1059                         break;
1060 
1061                 session->mru = val;
1062                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set mru=%d\n",
1063                           session->name, session->mru);
1064                 err = 0;
1065                 break;
1066 
1067         case PPPIOCGFLAGS:
1068                 err = -EFAULT;
1069                 if (put_user(ps->flags, (int __user *) arg))
1070                         break;
1071 
1072                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get flags=%d\n",
1073                           session->name, ps->flags);
1074                 err = 0;
1075                 break;
1076 
1077         case PPPIOCSFLAGS:
1078                 err = -EFAULT;
1079                 if (get_user(val, (int __user *) arg))
1080                         break;
1081                 ps->flags = val;
1082                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set flags=%d\n",
1083                           session->name, ps->flags);
1084                 err = 0;
1085                 break;
1086 
1087         case PPPIOCGL2TPSTATS:
1088                 err = -ENXIO;
1089                 if (!(sk->sk_state & PPPOX_CONNECTED))
1090                         break;
1091 
1092                 memset(&stats, 0, sizeof(stats));
1093                 stats.tunnel_id = tunnel->tunnel_id;
1094                 stats.session_id = session->session_id;
1095                 pppol2tp_copy_stats(&stats, &session->stats);
1096                 if (copy_to_user((void __user *) arg, &stats,
1097                                  sizeof(stats)))
1098                         break;
1099                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get L2TP stats\n",
1100                           session->name);
1101                 err = 0;
1102                 break;
1103 
1104         default:
1105                 err = -ENOSYS;
1106                 break;
1107         }
1108 
1109         sock_put(sk);
1110 
1111         return err;
1112 }
1113 
1114 /* Tunnel ioctl helper.
1115  *
1116  * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1117  * specifies a session_id, the session ioctl handler is called. This allows an
1118  * application to retrieve session stats via a tunnel socket.
1119  */
1120 static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
1121                                  unsigned int cmd, unsigned long arg)
1122 {
1123         int err = 0;
1124         struct sock *sk;
1125         struct pppol2tp_ioc_stats stats;
1126 
1127         l2tp_dbg(tunnel, PPPOL2TP_MSG_CONTROL,
1128                  "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n",
1129                  tunnel->name, cmd, arg);
1130 
1131         sk = tunnel->sock;
1132         sock_hold(sk);
1133 
1134         switch (cmd) {
1135         case PPPIOCGL2TPSTATS:
1136                 err = -ENXIO;
1137                 if (!(sk->sk_state & PPPOX_CONNECTED))
1138                         break;
1139 
1140                 if (copy_from_user(&stats, (void __user *) arg,
1141                                    sizeof(stats))) {
1142                         err = -EFAULT;
1143                         break;
1144                 }
1145                 if (stats.session_id != 0) {
1146                         /* resend to session ioctl handler */
1147                         struct l2tp_session *session =
1148                                 l2tp_session_find(sock_net(sk), tunnel, stats.session_id);
1149                         if (session != NULL)
1150                                 err = pppol2tp_session_ioctl(session, cmd, arg);
1151                         else
1152                                 err = -EBADR;
1153                         break;
1154                 }
1155 #ifdef CONFIG_XFRM
1156                 stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
1157 #endif
1158                 pppol2tp_copy_stats(&stats, &tunnel->stats);
1159                 if (copy_to_user((void __user *) arg, &stats, sizeof(stats))) {
1160                         err = -EFAULT;
1161                         break;
1162                 }
1163                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: get L2TP stats\n",
1164                           tunnel->name);
1165                 err = 0;
1166                 break;
1167 
1168         default:
1169                 err = -ENOSYS;
1170                 break;
1171         }
1172 
1173         sock_put(sk);
1174 
1175         return err;
1176 }
1177 
1178 /* Main ioctl() handler.
1179  * Dispatch to tunnel or session helpers depending on the socket.
1180  */
1181 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1182                           unsigned long arg)
1183 {
1184         struct sock *sk = sock->sk;
1185         struct l2tp_session *session;
1186         struct l2tp_tunnel *tunnel;
1187         struct pppol2tp_session *ps;
1188         int err;
1189 
1190         if (!sk)
1191                 return 0;
1192 
1193         err = -EBADF;
1194         if (sock_flag(sk, SOCK_DEAD) != 0)
1195                 goto end;
1196 
1197         err = -ENOTCONN;
1198         if ((sk->sk_user_data == NULL) ||
1199             (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
1200                 goto end;
1201 
1202         /* Get session context from the socket */
1203         err = -EBADF;
1204         session = pppol2tp_sock_to_session(sk);
1205         if (session == NULL)
1206                 goto end;
1207 
1208         /* Special case: if session's session_id is zero, treat ioctl as a
1209          * tunnel ioctl
1210          */
1211         ps = l2tp_session_priv(session);
1212         if ((session->session_id == 0) &&
1213             (session->peer_session_id == 0)) {
1214                 err = -EBADF;
1215                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1216                 if (tunnel == NULL)
1217                         goto end_put_sess;
1218 
1219                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
1220                 sock_put(ps->tunnel_sock);
1221                 goto end_put_sess;
1222         }
1223 
1224         err = pppol2tp_session_ioctl(session, cmd, arg);
1225 
1226 end_put_sess:
1227         sock_put(sk);
1228 end:
1229         return err;
1230 }
1231 
1232 /*****************************************************************************
1233  * setsockopt() / getsockopt() support.
1234  *
1235  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1236  * sockets. In order to control kernel tunnel features, we allow userspace to
1237  * create a special "tunnel" PPPoX socket which is used for control only.
1238  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1239  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1240  *****************************************************************************/
1241 
1242 /* Tunnel setsockopt() helper.
1243  */
1244 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1245                                       struct l2tp_tunnel *tunnel,
1246                                       int optname, int val)
1247 {
1248         int err = 0;
1249 
1250         switch (optname) {
1251         case PPPOL2TP_SO_DEBUG:
1252                 tunnel->debug = val;
1253                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: set debug=%x\n",
1254                           tunnel->name, tunnel->debug);
1255                 break;
1256 
1257         default:
1258                 err = -ENOPROTOOPT;
1259                 break;
1260         }
1261 
1262         return err;
1263 }
1264 
1265 /* Session setsockopt helper.
1266  */
1267 static int pppol2tp_session_setsockopt(struct sock *sk,
1268                                        struct l2tp_session *session,
1269                                        int optname, int val)
1270 {
1271         int err = 0;
1272         struct pppol2tp_session *ps = l2tp_session_priv(session);
1273 
1274         switch (optname) {
1275         case PPPOL2TP_SO_RECVSEQ:
1276                 if ((val != 0) && (val != 1)) {
1277                         err = -EINVAL;
1278                         break;
1279                 }
1280                 session->recv_seq = val ? -1 : 0;
1281                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1282                           "%s: set recv_seq=%d\n",
1283                           session->name, session->recv_seq);
1284                 break;
1285 
1286         case PPPOL2TP_SO_SENDSEQ:
1287                 if ((val != 0) && (val != 1)) {
1288                         err = -EINVAL;
1289                         break;
1290                 }
1291                 session->send_seq = val ? -1 : 0;
1292                 {
1293                         struct sock *ssk      = ps->sock;
1294                         struct pppox_sock *po = pppox_sk(ssk);
1295                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1296                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1297                 }
1298                 l2tp_session_set_header_len(session, session->tunnel->version);
1299                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1300                           "%s: set send_seq=%d\n",
1301                           session->name, session->send_seq);
1302                 break;
1303 
1304         case PPPOL2TP_SO_LNSMODE:
1305                 if ((val != 0) && (val != 1)) {
1306                         err = -EINVAL;
1307                         break;
1308                 }
1309                 session->lns_mode = val ? -1 : 0;
1310                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1311                           "%s: set lns_mode=%d\n",
1312                           session->name, session->lns_mode);
1313                 break;
1314 
1315         case PPPOL2TP_SO_DEBUG:
1316                 session->debug = val;
1317                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set debug=%x\n",
1318                           session->name, session->debug);
1319                 break;
1320 
1321         case PPPOL2TP_SO_REORDERTO:
1322                 session->reorder_timeout = msecs_to_jiffies(val);
1323                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1324                           "%s: set reorder_timeout=%d\n",
1325                           session->name, session->reorder_timeout);
1326                 break;
1327 
1328         default:
1329                 err = -ENOPROTOOPT;
1330                 break;
1331         }
1332 
1333         return err;
1334 }
1335 
1336 /* Main setsockopt() entry point.
1337  * Does API checks, then calls either the tunnel or session setsockopt
1338  * handler, according to whether the PPPoL2TP socket is a for a regular
1339  * session or the special tunnel type.
1340  */
1341 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1342                                char __user *optval, unsigned int optlen)
1343 {
1344         struct sock *sk = sock->sk;
1345         struct l2tp_session *session;
1346         struct l2tp_tunnel *tunnel;
1347         struct pppol2tp_session *ps;
1348         int val;
1349         int err;
1350 
1351         if (level != SOL_PPPOL2TP)
1352                 return -EINVAL;
1353 
1354         if (optlen < sizeof(int))
1355                 return -EINVAL;
1356 
1357         if (get_user(val, (int __user *)optval))
1358                 return -EFAULT;
1359 
1360         err = -ENOTCONN;
1361         if (sk->sk_user_data == NULL)
1362                 goto end;
1363 
1364         /* Get session context from the socket */
1365         err = -EBADF;
1366         session = pppol2tp_sock_to_session(sk);
1367         if (session == NULL)
1368                 goto end;
1369 
1370         /* Special case: if session_id == 0x0000, treat as operation on tunnel
1371          */
1372         ps = l2tp_session_priv(session);
1373         if ((session->session_id == 0) &&
1374             (session->peer_session_id == 0)) {
1375                 err = -EBADF;
1376                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1377                 if (tunnel == NULL)
1378                         goto end_put_sess;
1379 
1380                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1381                 sock_put(ps->tunnel_sock);
1382         } else
1383                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1384 
1385         err = 0;
1386 
1387 end_put_sess:
1388         sock_put(sk);
1389 end:
1390         return err;
1391 }
1392 
1393 /* Tunnel getsockopt helper. Called with sock locked.
1394  */
1395 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1396                                       struct l2tp_tunnel *tunnel,
1397                                       int optname, int *val)
1398 {
1399         int err = 0;
1400 
1401         switch (optname) {
1402         case PPPOL2TP_SO_DEBUG:
1403                 *val = tunnel->debug;
1404                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: get debug=%x\n",
1405                           tunnel->name, tunnel->debug);
1406                 break;
1407 
1408         default:
1409                 err = -ENOPROTOOPT;
1410                 break;
1411         }
1412 
1413         return err;
1414 }
1415 
1416 /* Session getsockopt helper. Called with sock locked.
1417  */
1418 static int pppol2tp_session_getsockopt(struct sock *sk,
1419                                        struct l2tp_session *session,
1420                                        int optname, int *val)
1421 {
1422         int err = 0;
1423 
1424         switch (optname) {
1425         case PPPOL2TP_SO_RECVSEQ:
1426                 *val = session->recv_seq;
1427                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1428                           "%s: get recv_seq=%d\n", session->name, *val);
1429                 break;
1430 
1431         case PPPOL2TP_SO_SENDSEQ:
1432                 *val = session->send_seq;
1433                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1434                           "%s: get send_seq=%d\n", session->name, *val);
1435                 break;
1436 
1437         case PPPOL2TP_SO_LNSMODE:
1438                 *val = session->lns_mode;
1439                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1440                           "%s: get lns_mode=%d\n", session->name, *val);
1441                 break;
1442 
1443         case PPPOL2TP_SO_DEBUG:
1444                 *val = session->debug;
1445                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get debug=%d\n",
1446                           session->name, *val);
1447                 break;
1448 
1449         case PPPOL2TP_SO_REORDERTO:
1450                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
1451                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1452                           "%s: get reorder_timeout=%d\n", session->name, *val);
1453                 break;
1454 
1455         default:
1456                 err = -ENOPROTOOPT;
1457         }
1458 
1459         return err;
1460 }
1461 
1462 /* Main getsockopt() entry point.
1463  * Does API checks, then calls either the tunnel or session getsockopt
1464  * handler, according to whether the PPPoX socket is a for a regular session
1465  * or the special tunnel type.
1466  */
1467 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1468                                char __user *optval, int __user *optlen)
1469 {
1470         struct sock *sk = sock->sk;
1471         struct l2tp_session *session;
1472         struct l2tp_tunnel *tunnel;
1473         int val, len;
1474         int err;
1475         struct pppol2tp_session *ps;
1476 
1477         if (level != SOL_PPPOL2TP)
1478                 return -EINVAL;
1479 
1480         if (get_user(len, optlen))
1481                 return -EFAULT;
1482 
1483         len = min_t(unsigned int, len, sizeof(int));
1484 
1485         if (len < 0)
1486                 return -EINVAL;
1487 
1488         err = -ENOTCONN;
1489         if (sk->sk_user_data == NULL)
1490                 goto end;
1491 
1492         /* Get the session context */
1493         err = -EBADF;
1494         session = pppol2tp_sock_to_session(sk);
1495         if (session == NULL)
1496                 goto end;
1497 
1498         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1499         ps = l2tp_session_priv(session);
1500         if ((session->session_id == 0) &&
1501             (session->peer_session_id == 0)) {
1502                 err = -EBADF;
1503                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1504                 if (tunnel == NULL)
1505                         goto end_put_sess;
1506 
1507                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1508                 sock_put(ps->tunnel_sock);
1509         } else
1510                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1511 
1512         err = -EFAULT;
1513         if (put_user(len, optlen))
1514                 goto end_put_sess;
1515 
1516         if (copy_to_user((void __user *) optval, &val, len))
1517                 goto end_put_sess;
1518 
1519         err = 0;
1520 
1521 end_put_sess:
1522         sock_put(sk);
1523 end:
1524         return err;
1525 }
1526 
1527 /*****************************************************************************
1528  * /proc filesystem for debug
1529  * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1530  * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1531  *****************************************************************************/
1532 
1533 static unsigned int pppol2tp_net_id;
1534 
1535 #ifdef CONFIG_PROC_FS
1536 
1537 struct pppol2tp_seq_data {
1538         struct seq_net_private p;
1539         int tunnel_idx;                 /* current tunnel */
1540         int session_idx;                /* index of session within current tunnel */
1541         struct l2tp_tunnel *tunnel;
1542         struct l2tp_session *session;   /* NULL means get next tunnel */
1543 };
1544 
1545 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1546 {
1547         for (;;) {
1548                 pd->tunnel = l2tp_tunnel_find_nth(net, pd->tunnel_idx);
1549                 pd->tunnel_idx++;
1550 
1551                 if (pd->tunnel == NULL)
1552                         break;
1553 
1554                 /* Ignore L2TPv3 tunnels */
1555                 if (pd->tunnel->version < 3)
1556                         break;
1557         }
1558 }
1559 
1560 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1561 {
1562         pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
1563         pd->session_idx++;
1564 
1565         if (pd->session == NULL) {
1566                 pd->session_idx = 0;
1567                 pppol2tp_next_tunnel(net, pd);
1568         }
1569 }
1570 
1571 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1572 {
1573         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1574         loff_t pos = *offs;
1575         struct net *net;
1576 
1577         if (!pos)
1578                 goto out;
1579 
1580         BUG_ON(m->private == NULL);
1581         pd = m->private;
1582         net = seq_file_net(m);
1583 
1584         if (pd->tunnel == NULL)
1585                 pppol2tp_next_tunnel(net, pd);
1586         else
1587                 pppol2tp_next_session(net, pd);
1588 
1589         /* NULL tunnel and session indicates end of list */
1590         if ((pd->tunnel == NULL) && (pd->session == NULL))
1591                 pd = NULL;
1592 
1593 out:
1594         return pd;
1595 }
1596 
1597 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1598 {
1599         (*pos)++;
1600         return NULL;
1601 }
1602 
1603 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1604 {
1605         /* nothing to do */
1606 }
1607 
1608 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1609 {
1610         struct l2tp_tunnel *tunnel = v;
1611 
1612         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1613                    tunnel->name,
1614                    (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N',
1615                    atomic_read(&tunnel->ref_count) - 1);
1616         seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1617                    tunnel->debug,
1618                    atomic_long_read(&tunnel->stats.tx_packets),
1619                    atomic_long_read(&tunnel->stats.tx_bytes),
1620                    atomic_long_read(&tunnel->stats.tx_errors),
1621                    atomic_long_read(&tunnel->stats.rx_packets),
1622                    atomic_long_read(&tunnel->stats.rx_bytes),
1623                    atomic_long_read(&tunnel->stats.rx_errors));
1624 }
1625 
1626 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1627 {
1628         struct l2tp_session *session = v;
1629         struct l2tp_tunnel *tunnel = session->tunnel;
1630         struct pppol2tp_session *ps = l2tp_session_priv(session);
1631         struct pppox_sock *po = pppox_sk(ps->sock);
1632         u32 ip = 0;
1633         u16 port = 0;
1634 
1635         if (tunnel->sock) {
1636                 struct inet_sock *inet = inet_sk(tunnel->sock);
1637                 ip = ntohl(inet->inet_saddr);
1638                 port = ntohs(inet->inet_sport);
1639         }
1640 
1641         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
1642                    "%04X/%04X %d %c\n",
1643                    session->name, ip, port,
1644                    tunnel->tunnel_id,
1645                    session->session_id,
1646                    tunnel->peer_tunnel_id,
1647                    session->peer_session_id,
1648                    ps->sock->sk_state,
1649                    (session == ps->sock->sk_user_data) ?
1650                    'Y' : 'N');
1651         seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
1652                    session->mtu, session->mru,
1653                    session->recv_seq ? 'R' : '-',
1654                    session->send_seq ? 'S' : '-',
1655                    session->lns_mode ? "LNS" : "LAC",
1656                    session->debug,
1657                    jiffies_to_msecs(session->reorder_timeout));
1658         seq_printf(m, "   %hu/%hu %ld/%ld/%ld %ld/%ld/%ld\n",
1659                    session->nr, session->ns,
1660                    atomic_long_read(&session->stats.tx_packets),
1661                    atomic_long_read(&session->stats.tx_bytes),
1662                    atomic_long_read(&session->stats.tx_errors),
1663                    atomic_long_read(&session->stats.rx_packets),
1664                    atomic_long_read(&session->stats.rx_bytes),
1665                    atomic_long_read(&session->stats.rx_errors));
1666 
1667         if (po)
1668                 seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
1669 }
1670 
1671 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1672 {
1673         struct pppol2tp_seq_data *pd = v;
1674 
1675         /* display header on line 1 */
1676         if (v == SEQ_START_TOKEN) {
1677                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1678                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1679                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1680                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
1681                          "dest-tid/sid state user-data-ok\n");
1682                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1683                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1684                 goto out;
1685         }
1686 
1687         /* Show the tunnel or session context.
1688          */
1689         if (pd->session == NULL)
1690                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1691         else
1692                 pppol2tp_seq_session_show(m, pd->session);
1693 
1694 out:
1695         return 0;
1696 }
1697 
1698 static const struct seq_operations pppol2tp_seq_ops = {
1699         .start          = pppol2tp_seq_start,
1700         .next           = pppol2tp_seq_next,
1701         .stop           = pppol2tp_seq_stop,
1702         .show           = pppol2tp_seq_show,
1703 };
1704 
1705 /* Called when our /proc file is opened. We allocate data for use when
1706  * iterating our tunnel / session contexts and store it in the private
1707  * data of the seq_file.
1708  */
1709 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
1710 {
1711         return seq_open_net(inode, file, &pppol2tp_seq_ops,
1712                             sizeof(struct pppol2tp_seq_data));
1713 }
1714 
1715 static const struct file_operations pppol2tp_proc_fops = {
1716         .owner          = THIS_MODULE,
1717         .open           = pppol2tp_proc_open,
1718         .read           = seq_read,
1719         .llseek         = seq_lseek,
1720         .release        = seq_release_net,
1721 };
1722 
1723 #endif /* CONFIG_PROC_FS */
1724 
1725 /*****************************************************************************
1726  * Network namespace
1727  *****************************************************************************/
1728 
1729 static __net_init int pppol2tp_init_net(struct net *net)
1730 {
1731         struct proc_dir_entry *pde;
1732         int err = 0;
1733 
1734         pde = proc_create("pppol2tp", S_IRUGO, net->proc_net,
1735                           &pppol2tp_proc_fops);
1736         if (!pde) {
1737                 err = -ENOMEM;
1738                 goto out;
1739         }
1740 
1741 out:
1742         return err;
1743 }
1744 
1745 static __net_exit void pppol2tp_exit_net(struct net *net)
1746 {
1747         remove_proc_entry("pppol2tp", net->proc_net);
1748 }
1749 
1750 static struct pernet_operations pppol2tp_net_ops = {
1751         .init = pppol2tp_init_net,
1752         .exit = pppol2tp_exit_net,
1753         .id   = &pppol2tp_net_id,
1754 };
1755 
1756 /*****************************************************************************
1757  * Init and cleanup
1758  *****************************************************************************/
1759 
1760 static const struct proto_ops pppol2tp_ops = {
1761         .family         = AF_PPPOX,
1762         .owner          = THIS_MODULE,
1763         .release        = pppol2tp_release,
1764         .bind           = sock_no_bind,
1765         .connect        = pppol2tp_connect,
1766         .socketpair     = sock_no_socketpair,
1767         .accept         = sock_no_accept,
1768         .getname        = pppol2tp_getname,
1769         .poll           = datagram_poll,
1770         .listen         = sock_no_listen,
1771         .shutdown       = sock_no_shutdown,
1772         .setsockopt     = pppol2tp_setsockopt,
1773         .getsockopt     = pppol2tp_getsockopt,
1774         .sendmsg        = pppol2tp_sendmsg,
1775         .recvmsg        = pppol2tp_recvmsg,
1776         .mmap           = sock_no_mmap,
1777         .ioctl          = pppox_ioctl,
1778 };
1779 
1780 static const struct pppox_proto pppol2tp_proto = {
1781         .create         = pppol2tp_create,
1782         .ioctl          = pppol2tp_ioctl,
1783         .owner          = THIS_MODULE,
1784 };
1785 
1786 #ifdef CONFIG_L2TP_V3
1787 
1788 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1789         .session_create = pppol2tp_session_create,
1790         .session_delete = l2tp_session_delete,
1791 };
1792 
1793 #endif /* CONFIG_L2TP_V3 */
1794 
1795 static int __init pppol2tp_init(void)
1796 {
1797         int err;
1798 
1799         err = register_pernet_device(&pppol2tp_net_ops);
1800         if (err)
1801                 goto out;
1802 
1803         err = proto_register(&pppol2tp_sk_proto, 0);
1804         if (err)
1805                 goto out_unregister_pppol2tp_pernet;
1806 
1807         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1808         if (err)
1809                 goto out_unregister_pppol2tp_proto;
1810 
1811 #ifdef CONFIG_L2TP_V3
1812         err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1813         if (err)
1814                 goto out_unregister_pppox;
1815 #endif
1816 
1817         pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1818 
1819 out:
1820         return err;
1821 
1822 #ifdef CONFIG_L2TP_V3
1823 out_unregister_pppox:
1824         unregister_pppox_proto(PX_PROTO_OL2TP);
1825 #endif
1826 out_unregister_pppol2tp_proto:
1827         proto_unregister(&pppol2tp_sk_proto);
1828 out_unregister_pppol2tp_pernet:
1829         unregister_pernet_device(&pppol2tp_net_ops);
1830         goto out;
1831 }
1832 
1833 static void __exit pppol2tp_exit(void)
1834 {
1835 #ifdef CONFIG_L2TP_V3
1836         l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1837 #endif
1838         unregister_pppox_proto(PX_PROTO_OL2TP);
1839         proto_unregister(&pppol2tp_sk_proto);
1840         unregister_pernet_device(&pppol2tp_net_ops);
1841 }
1842 
1843 module_init(pppol2tp_init);
1844 module_exit(pppol2tp_exit);
1845 
1846 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1847 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1848 MODULE_LICENSE("GPL");
1849 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1850 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OL2TP);
1851 MODULE_ALIAS_L2TP_PWTYPE(11);
1852 

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