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

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.75 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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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                 l2tp_dbg(session, PPPOL2TP_MSG_DATA,
234                          "%s: recv %d byte data frame, passing to ppp\n",
235                          session->name, data_len);
236 
237                 /* We need to forget all info related to the L2TP packet
238                  * gathered in the skb as we are going to reuse the same
239                  * skb for the inner packet.
240                  * Namely we need to:
241                  * - reset xfrm (IPSec) information as it applies to
242                  *   the outer L2TP packet and not to the inner one
243                  * - release the dst to force a route lookup on the inner
244                  *   IP packet since skb->dst currently points to the dst
245                  *   of the UDP tunnel
246                  * - reset netfilter information as it doesn't apply
247                  *   to the inner packet either
248                  */
249                 secpath_reset(skb);
250                 skb_dst_drop(skb);
251                 nf_reset(skb);
252 
253                 po = pppox_sk(sk);
254                 ppp_input(&po->chan, skb);
255         } else {
256                 l2tp_dbg(session, PPPOL2TP_MSG_DATA,
257                          "%s: recv %d byte data frame, passing to L2TP socket\n",
258                          session->name, data_len);
259 
260                 if (sock_queue_rcv_skb(sk, skb) < 0) {
261                         atomic_long_inc(&session->stats.rx_errors);
262                         kfree_skb(skb);
263                 }
264         }
265 
266         return;
267 
268 no_sock:
269         l2tp_info(session, PPPOL2TP_MSG_DATA, "%s: no socket\n", session->name);
270         kfree_skb(skb);
271 }
272 
273 static void pppol2tp_session_sock_hold(struct l2tp_session *session)
274 {
275         struct pppol2tp_session *ps = l2tp_session_priv(session);
276 
277         if (ps->sock)
278                 sock_hold(ps->sock);
279 }
280 
281 static void pppol2tp_session_sock_put(struct l2tp_session *session)
282 {
283         struct pppol2tp_session *ps = l2tp_session_priv(session);
284 
285         if (ps->sock)
286                 sock_put(ps->sock);
287 }
288 
289 /************************************************************************
290  * Transmit handling
291  ***********************************************************************/
292 
293 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
294  * when a user application does a sendmsg() on the session socket. L2TP and
295  * PPP headers must be inserted into the user's data.
296  */
297 static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
298                             size_t total_len)
299 {
300         static const unsigned char ppph[2] = { 0xff, 0x03 };
301         struct sock *sk = sock->sk;
302         struct sk_buff *skb;
303         int error;
304         struct l2tp_session *session;
305         struct l2tp_tunnel *tunnel;
306         struct pppol2tp_session *ps;
307         int uhlen;
308 
309         error = -ENOTCONN;
310         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
311                 goto error;
312 
313         /* Get session and tunnel contexts */
314         error = -EBADF;
315         session = pppol2tp_sock_to_session(sk);
316         if (session == NULL)
317                 goto error;
318 
319         ps = l2tp_session_priv(session);
320         tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
321         if (tunnel == NULL)
322                 goto error_put_sess;
323 
324         uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
325 
326         /* Allocate a socket buffer */
327         error = -ENOMEM;
328         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
329                            uhlen + session->hdr_len +
330                            sizeof(ppph) + total_len,
331                            0, GFP_KERNEL);
332         if (!skb)
333                 goto error_put_sess_tun;
334 
335         /* Reserve space for headers. */
336         skb_reserve(skb, NET_SKB_PAD);
337         skb_reset_network_header(skb);
338         skb_reserve(skb, sizeof(struct iphdr));
339         skb_reset_transport_header(skb);
340         skb_reserve(skb, uhlen);
341 
342         /* Add PPP header */
343         skb->data[0] = ppph[0];
344         skb->data[1] = ppph[1];
345         skb_put(skb, 2);
346 
347         /* Copy user data into skb */
348         error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
349         if (error < 0) {
350                 kfree_skb(skb);
351                 goto error_put_sess_tun;
352         }
353 
354         local_bh_disable();
355         l2tp_xmit_skb(session, skb, session->hdr_len);
356         local_bh_enable();
357 
358         sock_put(ps->tunnel_sock);
359         sock_put(sk);
360 
361         return total_len;
362 
363 error_put_sess_tun:
364         sock_put(ps->tunnel_sock);
365 error_put_sess:
366         sock_put(sk);
367 error:
368         return error;
369 }
370 
371 /* Transmit function called by generic PPP driver.  Sends PPP frame
372  * over PPPoL2TP socket.
373  *
374  * This is almost the same as pppol2tp_sendmsg(), but rather than
375  * being called with a msghdr from userspace, it is called with a skb
376  * from the kernel.
377  *
378  * The supplied skb from ppp doesn't have enough headroom for the
379  * insertion of L2TP, UDP and IP headers so we need to allocate more
380  * headroom in the skb. This will create a cloned skb. But we must be
381  * careful in the error case because the caller will expect to free
382  * the skb it supplied, not our cloned skb. So we take care to always
383  * leave the original skb unfreed if we return an error.
384  */
385 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
386 {
387         static const u8 ppph[2] = { 0xff, 0x03 };
388         struct sock *sk = (struct sock *) chan->private;
389         struct sock *sk_tun;
390         struct l2tp_session *session;
391         struct l2tp_tunnel *tunnel;
392         struct pppol2tp_session *ps;
393         int uhlen, headroom;
394 
395         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
396                 goto abort;
397 
398         /* Get session and tunnel contexts from the socket */
399         session = pppol2tp_sock_to_session(sk);
400         if (session == NULL)
401                 goto abort;
402 
403         ps = l2tp_session_priv(session);
404         sk_tun = ps->tunnel_sock;
405         if (sk_tun == NULL)
406                 goto abort_put_sess;
407         tunnel = l2tp_sock_to_tunnel(sk_tun);
408         if (tunnel == NULL)
409                 goto abort_put_sess;
410 
411         uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
412         headroom = NET_SKB_PAD +
413                    sizeof(struct iphdr) + /* IP header */
414                    uhlen +              /* UDP header (if L2TP_ENCAPTYPE_UDP) */
415                    session->hdr_len +   /* L2TP header */
416                    sizeof(ppph);        /* PPP header */
417         if (skb_cow_head(skb, headroom))
418                 goto abort_put_sess_tun;
419 
420         /* Setup PPP header */
421         __skb_push(skb, sizeof(ppph));
422         skb->data[0] = ppph[0];
423         skb->data[1] = ppph[1];
424 
425         local_bh_disable();
426         l2tp_xmit_skb(session, skb, session->hdr_len);
427         local_bh_enable();
428 
429         sock_put(sk_tun);
430         sock_put(sk);
431         return 1;
432 
433 abort_put_sess_tun:
434         sock_put(sk_tun);
435 abort_put_sess:
436         sock_put(sk);
437 abort:
438         /* Free the original skb */
439         kfree_skb(skb);
440         return 1;
441 }
442 
443 /*****************************************************************************
444  * Session (and tunnel control) socket create/destroy.
445  *****************************************************************************/
446 
447 /* Called by l2tp_core when a session socket is being closed.
448  */
449 static void pppol2tp_session_close(struct l2tp_session *session)
450 {
451         struct pppol2tp_session *ps = l2tp_session_priv(session);
452         struct sock *sk = ps->sock;
453         struct socket *sock = sk->sk_socket;
454 
455         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
456 
457         if (sock) {
458                 inet_shutdown(sock, 2);
459                 /* Don't let the session go away before our socket does */
460                 l2tp_session_inc_refcount(session);
461         }
462 }
463 
464 /* Really kill the session socket. (Called from sock_put() if
465  * refcnt == 0.)
466  */
467 static void pppol2tp_session_destruct(struct sock *sk)
468 {
469         struct l2tp_session *session = sk->sk_user_data;
470         if (session) {
471                 sk->sk_user_data = NULL;
472                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
473                 l2tp_session_dec_refcount(session);
474         }
475 }
476 
477 /* Called when the PPPoX socket (session) is closed.
478  */
479 static int pppol2tp_release(struct socket *sock)
480 {
481         struct sock *sk = sock->sk;
482         struct l2tp_session *session;
483         int error;
484 
485         if (!sk)
486                 return 0;
487 
488         error = -EBADF;
489         lock_sock(sk);
490         if (sock_flag(sk, SOCK_DEAD) != 0)
491                 goto error;
492 
493         pppox_unbind_sock(sk);
494 
495         /* Signal the death of the socket. */
496         sk->sk_state = PPPOX_DEAD;
497         sock_orphan(sk);
498         sock->sk = NULL;
499 
500         session = pppol2tp_sock_to_session(sk);
501 
502         /* Purge any queued data */
503         if (session != NULL) {
504                 __l2tp_session_unhash(session);
505                 l2tp_session_queue_purge(session);
506                 sock_put(sk);
507         }
508         skb_queue_purge(&sk->sk_receive_queue);
509         skb_queue_purge(&sk->sk_write_queue);
510 
511         release_sock(sk);
512 
513         /* This will delete the session context via
514          * pppol2tp_session_destruct() if the socket's refcnt drops to
515          * zero.
516          */
517         sock_put(sk);
518 
519         return 0;
520 
521 error:
522         release_sock(sk);
523         return error;
524 }
525 
526 static struct proto pppol2tp_sk_proto = {
527         .name     = "PPPOL2TP",
528         .owner    = THIS_MODULE,
529         .obj_size = sizeof(struct pppox_sock),
530 };
531 
532 static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
533 {
534         int rc;
535 
536         rc = l2tp_udp_encap_recv(sk, skb);
537         if (rc)
538                 kfree_skb(skb);
539 
540         return NET_RX_SUCCESS;
541 }
542 
543 /* socket() handler. Initialize a new struct sock.
544  */
545 static int pppol2tp_create(struct net *net, struct socket *sock, int kern)
546 {
547         int error = -ENOMEM;
548         struct sock *sk;
549 
550         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto, kern);
551         if (!sk)
552                 goto out;
553 
554         sock_init_data(sock, sk);
555 
556         sock->state  = SS_UNCONNECTED;
557         sock->ops    = &pppol2tp_ops;
558 
559         sk->sk_backlog_rcv = pppol2tp_backlog_recv;
560         sk->sk_protocol    = PX_PROTO_OL2TP;
561         sk->sk_family      = PF_PPPOX;
562         sk->sk_state       = PPPOX_NONE;
563         sk->sk_type        = SOCK_STREAM;
564         sk->sk_destruct    = pppol2tp_session_destruct;
565 
566         error = 0;
567 
568 out:
569         return error;
570 }
571 
572 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
573 static void pppol2tp_show(struct seq_file *m, void *arg)
574 {
575         struct l2tp_session *session = arg;
576         struct pppol2tp_session *ps = l2tp_session_priv(session);
577 
578         if (ps) {
579                 struct pppox_sock *po = pppox_sk(ps->sock);
580                 if (po)
581                         seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
582         }
583 }
584 #endif
585 
586 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
587  */
588 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
589                             int sockaddr_len, int flags)
590 {
591         struct sock *sk = sock->sk;
592         struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
593         struct pppox_sock *po = pppox_sk(sk);
594         struct l2tp_session *session = NULL;
595         struct l2tp_tunnel *tunnel;
596         struct pppol2tp_session *ps;
597         struct dst_entry *dst;
598         struct l2tp_session_cfg cfg = { 0, };
599         int error = 0;
600         u32 tunnel_id, peer_tunnel_id;
601         u32 session_id, peer_session_id;
602         int ver = 2;
603         int fd;
604 
605         lock_sock(sk);
606 
607         error = -EINVAL;
608         if (sp->sa_protocol != PX_PROTO_OL2TP)
609                 goto end;
610 
611         /* Check for already bound sockets */
612         error = -EBUSY;
613         if (sk->sk_state & PPPOX_CONNECTED)
614                 goto end;
615 
616         /* We don't supporting rebinding anyway */
617         error = -EALREADY;
618         if (sk->sk_user_data)
619                 goto end; /* socket is already attached */
620 
621         /* Get params from socket address. Handle L2TPv2 and L2TPv3.
622          * This is nasty because there are different sockaddr_pppol2tp
623          * structs for L2TPv2, L2TPv3, over IPv4 and IPv6. We use
624          * the sockaddr size to determine which structure the caller
625          * is using.
626          */
627         peer_tunnel_id = 0;
628         if (sockaddr_len == sizeof(struct sockaddr_pppol2tp)) {
629                 fd = sp->pppol2tp.fd;
630                 tunnel_id = sp->pppol2tp.s_tunnel;
631                 peer_tunnel_id = sp->pppol2tp.d_tunnel;
632                 session_id = sp->pppol2tp.s_session;
633                 peer_session_id = sp->pppol2tp.d_session;
634         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3)) {
635                 struct sockaddr_pppol2tpv3 *sp3 =
636                         (struct sockaddr_pppol2tpv3 *) sp;
637                 ver = 3;
638                 fd = sp3->pppol2tp.fd;
639                 tunnel_id = sp3->pppol2tp.s_tunnel;
640                 peer_tunnel_id = sp3->pppol2tp.d_tunnel;
641                 session_id = sp3->pppol2tp.s_session;
642                 peer_session_id = sp3->pppol2tp.d_session;
643         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpin6)) {
644                 struct sockaddr_pppol2tpin6 *sp6 =
645                         (struct sockaddr_pppol2tpin6 *) sp;
646                 fd = sp6->pppol2tp.fd;
647                 tunnel_id = sp6->pppol2tp.s_tunnel;
648                 peer_tunnel_id = sp6->pppol2tp.d_tunnel;
649                 session_id = sp6->pppol2tp.s_session;
650                 peer_session_id = sp6->pppol2tp.d_session;
651         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3in6)) {
652                 struct sockaddr_pppol2tpv3in6 *sp6 =
653                         (struct sockaddr_pppol2tpv3in6 *) sp;
654                 ver = 3;
655                 fd = sp6->pppol2tp.fd;
656                 tunnel_id = sp6->pppol2tp.s_tunnel;
657                 peer_tunnel_id = sp6->pppol2tp.d_tunnel;
658                 session_id = sp6->pppol2tp.s_session;
659                 peer_session_id = sp6->pppol2tp.d_session;
660         } else {
661                 error = -EINVAL;
662                 goto end; /* bad socket address */
663         }
664 
665         /* Don't bind if tunnel_id is 0 */
666         error = -EINVAL;
667         if (tunnel_id == 0)
668                 goto end;
669 
670         tunnel = l2tp_tunnel_find(sock_net(sk), tunnel_id);
671 
672         /* Special case: create tunnel context if session_id and
673          * peer_session_id is 0. Otherwise look up tunnel using supplied
674          * tunnel id.
675          */
676         if ((session_id == 0) && (peer_session_id == 0)) {
677                 if (tunnel == NULL) {
678                         struct l2tp_tunnel_cfg tcfg = {
679                                 .encap = L2TP_ENCAPTYPE_UDP,
680                                 .debug = 0,
681                         };
682                         error = l2tp_tunnel_create(sock_net(sk), fd, ver, tunnel_id, peer_tunnel_id, &tcfg, &tunnel);
683                         if (error < 0)
684                                 goto end;
685                 }
686         } else {
687                 /* Error if we can't find the tunnel */
688                 error = -ENOENT;
689                 if (tunnel == NULL)
690                         goto end;
691 
692                 /* Error if socket is not prepped */
693                 if (tunnel->sock == NULL)
694                         goto end;
695         }
696 
697         if (tunnel->recv_payload_hook == NULL)
698                 tunnel->recv_payload_hook = pppol2tp_recv_payload_hook;
699 
700         if (tunnel->peer_tunnel_id == 0)
701                 tunnel->peer_tunnel_id = peer_tunnel_id;
702 
703         /* Create session if it doesn't already exist. We handle the
704          * case where a session was previously created by the netlink
705          * interface by checking that the session doesn't already have
706          * a socket and its tunnel socket are what we expect. If any
707          * of those checks fail, return EEXIST to the caller.
708          */
709         session = l2tp_session_find(sock_net(sk), tunnel, session_id);
710         if (session == NULL) {
711                 /* Default MTU must allow space for UDP/L2TP/PPP
712                  * headers.
713                  */
714                 cfg.mtu = cfg.mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
715 
716                 /* Allocate and initialize a new session context. */
717                 session = l2tp_session_create(sizeof(struct pppol2tp_session),
718                                               tunnel, session_id,
719                                               peer_session_id, &cfg);
720                 if (session == NULL) {
721                         error = -ENOMEM;
722                         goto end;
723                 }
724         } else {
725                 ps = l2tp_session_priv(session);
726                 error = -EEXIST;
727                 if (ps->sock != NULL)
728                         goto end;
729 
730                 /* consistency checks */
731                 if (ps->tunnel_sock != tunnel->sock)
732                         goto end;
733         }
734 
735         /* Associate session with its PPPoL2TP socket */
736         ps = l2tp_session_priv(session);
737         ps->owner            = current->pid;
738         ps->sock             = sk;
739         ps->tunnel_sock = tunnel->sock;
740 
741         session->recv_skb       = pppol2tp_recv;
742         session->session_close  = pppol2tp_session_close;
743 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
744         session->show           = pppol2tp_show;
745 #endif
746 
747         /* We need to know each time a skb is dropped from the reorder
748          * queue.
749          */
750         session->ref = pppol2tp_session_sock_hold;
751         session->deref = pppol2tp_session_sock_put;
752 
753         /* If PMTU discovery was enabled, use the MTU that was discovered */
754         dst = sk_dst_get(tunnel->sock);
755         if (dst != NULL) {
756                 u32 pmtu = dst_mtu(dst);
757 
758                 if (pmtu != 0)
759                         session->mtu = session->mru = pmtu -
760                                 PPPOL2TP_HEADER_OVERHEAD;
761                 dst_release(dst);
762         }
763 
764         /* Special case: if source & dest session_id == 0x0000, this
765          * socket is being created to manage the tunnel. Just set up
766          * the internal context for use by ioctl() and sockopt()
767          * handlers.
768          */
769         if ((session->session_id == 0) &&
770             (session->peer_session_id == 0)) {
771                 error = 0;
772                 goto out_no_ppp;
773         }
774 
775         /* The only header we need to worry about is the L2TP
776          * header. This size is different depending on whether
777          * sequence numbers are enabled for the data channel.
778          */
779         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
780 
781         po->chan.private = sk;
782         po->chan.ops     = &pppol2tp_chan_ops;
783         po->chan.mtu     = session->mtu;
784 
785         error = ppp_register_net_channel(sock_net(sk), &po->chan);
786         if (error)
787                 goto end;
788 
789 out_no_ppp:
790         /* This is how we get the session context from the socket. */
791         sk->sk_user_data = session;
792         sk->sk_state = PPPOX_CONNECTED;
793         l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: created\n",
794                   session->name);
795 
796 end:
797         release_sock(sk);
798 
799         return error;
800 }
801 
802 #ifdef CONFIG_L2TP_V3
803 
804 /* Called when creating sessions via the netlink interface.
805  */
806 static int pppol2tp_session_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
807 {
808         int error;
809         struct l2tp_tunnel *tunnel;
810         struct l2tp_session *session;
811         struct pppol2tp_session *ps;
812 
813         tunnel = l2tp_tunnel_find(net, tunnel_id);
814 
815         /* Error if we can't find the tunnel */
816         error = -ENOENT;
817         if (tunnel == NULL)
818                 goto out;
819 
820         /* Error if tunnel socket is not prepped */
821         if (tunnel->sock == NULL)
822                 goto out;
823 
824         /* Check that this session doesn't already exist */
825         error = -EEXIST;
826         session = l2tp_session_find(net, tunnel, session_id);
827         if (session != NULL)
828                 goto out;
829 
830         /* Default MTU values. */
831         if (cfg->mtu == 0)
832                 cfg->mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
833         if (cfg->mru == 0)
834                 cfg->mru = cfg->mtu;
835 
836         /* Allocate and initialize a new session context. */
837         error = -ENOMEM;
838         session = l2tp_session_create(sizeof(struct pppol2tp_session),
839                                       tunnel, session_id,
840                                       peer_session_id, cfg);
841         if (session == NULL)
842                 goto out;
843 
844         ps = l2tp_session_priv(session);
845         ps->tunnel_sock = tunnel->sock;
846 
847         l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: created\n",
848                   session->name);
849 
850         error = 0;
851 
852 out:
853         return error;
854 }
855 
856 #endif /* CONFIG_L2TP_V3 */
857 
858 /* getname() support.
859  */
860 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
861                             int *usockaddr_len, int peer)
862 {
863         int len = 0;
864         int error = 0;
865         struct l2tp_session *session;
866         struct l2tp_tunnel *tunnel;
867         struct sock *sk = sock->sk;
868         struct inet_sock *inet;
869         struct pppol2tp_session *pls;
870 
871         error = -ENOTCONN;
872         if (sk == NULL)
873                 goto end;
874         if (sk->sk_state != PPPOX_CONNECTED)
875                 goto end;
876 
877         error = -EBADF;
878         session = pppol2tp_sock_to_session(sk);
879         if (session == NULL)
880                 goto end;
881 
882         pls = l2tp_session_priv(session);
883         tunnel = l2tp_sock_to_tunnel(pls->tunnel_sock);
884         if (tunnel == NULL) {
885                 error = -EBADF;
886                 goto end_put_sess;
887         }
888 
889         inet = inet_sk(tunnel->sock);
890         if ((tunnel->version == 2) && (tunnel->sock->sk_family == AF_INET)) {
891                 struct sockaddr_pppol2tp sp;
892                 len = sizeof(sp);
893                 memset(&sp, 0, len);
894                 sp.sa_family    = AF_PPPOX;
895                 sp.sa_protocol  = PX_PROTO_OL2TP;
896                 sp.pppol2tp.fd  = tunnel->fd;
897                 sp.pppol2tp.pid = pls->owner;
898                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
899                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
900                 sp.pppol2tp.s_session = session->session_id;
901                 sp.pppol2tp.d_session = session->peer_session_id;
902                 sp.pppol2tp.addr.sin_family = AF_INET;
903                 sp.pppol2tp.addr.sin_port = inet->inet_dport;
904                 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
905                 memcpy(uaddr, &sp, len);
906 #if IS_ENABLED(CONFIG_IPV6)
907         } else if ((tunnel->version == 2) &&
908                    (tunnel->sock->sk_family == AF_INET6)) {
909                 struct sockaddr_pppol2tpin6 sp;
910 
911                 len = sizeof(sp);
912                 memset(&sp, 0, len);
913                 sp.sa_family    = AF_PPPOX;
914                 sp.sa_protocol  = PX_PROTO_OL2TP;
915                 sp.pppol2tp.fd  = tunnel->fd;
916                 sp.pppol2tp.pid = pls->owner;
917                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
918                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
919                 sp.pppol2tp.s_session = session->session_id;
920                 sp.pppol2tp.d_session = session->peer_session_id;
921                 sp.pppol2tp.addr.sin6_family = AF_INET6;
922                 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
923                 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
924                        sizeof(tunnel->sock->sk_v6_daddr));
925                 memcpy(uaddr, &sp, len);
926         } else if ((tunnel->version == 3) &&
927                    (tunnel->sock->sk_family == AF_INET6)) {
928                 struct sockaddr_pppol2tpv3in6 sp;
929 
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.sin6_family = AF_INET6;
941                 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
942                 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
943                        sizeof(tunnel->sock->sk_v6_daddr));
944                 memcpy(uaddr, &sp, len);
945 #endif
946         } else if (tunnel->version == 3) {
947                 struct sockaddr_pppol2tpv3 sp;
948                 len = sizeof(sp);
949                 memset(&sp, 0, len);
950                 sp.sa_family    = AF_PPPOX;
951                 sp.sa_protocol  = PX_PROTO_OL2TP;
952                 sp.pppol2tp.fd  = tunnel->fd;
953                 sp.pppol2tp.pid = pls->owner;
954                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
955                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
956                 sp.pppol2tp.s_session = session->session_id;
957                 sp.pppol2tp.d_session = session->peer_session_id;
958                 sp.pppol2tp.addr.sin_family = AF_INET;
959                 sp.pppol2tp.addr.sin_port = inet->inet_dport;
960                 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
961                 memcpy(uaddr, &sp, len);
962         }
963 
964         *usockaddr_len = len;
965 
966         sock_put(pls->tunnel_sock);
967 end_put_sess:
968         sock_put(sk);
969         error = 0;
970 
971 end:
972         return error;
973 }
974 
975 /****************************************************************************
976  * ioctl() handlers.
977  *
978  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
979  * sockets. However, in order to control kernel tunnel features, we allow
980  * userspace to create a special "tunnel" PPPoX socket which is used for
981  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
982  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
983  * calls.
984  ****************************************************************************/
985 
986 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
987                                 struct l2tp_stats *stats)
988 {
989         dest->tx_packets = atomic_long_read(&stats->tx_packets);
990         dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
991         dest->tx_errors = atomic_long_read(&stats->tx_errors);
992         dest->rx_packets = atomic_long_read(&stats->rx_packets);
993         dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
994         dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
995         dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
996         dest->rx_errors = atomic_long_read(&stats->rx_errors);
997 }
998 
999 /* Session ioctl helper.
1000  */
1001 static int pppol2tp_session_ioctl(struct l2tp_session *session,
1002                                   unsigned int cmd, unsigned long arg)
1003 {
1004         struct ifreq ifr;
1005         int err = 0;
1006         struct sock *sk;
1007         int val = (int) arg;
1008         struct pppol2tp_session *ps = l2tp_session_priv(session);
1009         struct l2tp_tunnel *tunnel = session->tunnel;
1010         struct pppol2tp_ioc_stats stats;
1011 
1012         l2tp_dbg(session, PPPOL2TP_MSG_CONTROL,
1013                  "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
1014                  session->name, cmd, arg);
1015 
1016         sk = ps->sock;
1017         sock_hold(sk);
1018 
1019         switch (cmd) {
1020         case SIOCGIFMTU:
1021                 err = -ENXIO;
1022                 if (!(sk->sk_state & PPPOX_CONNECTED))
1023                         break;
1024 
1025                 err = -EFAULT;
1026                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1027                         break;
1028                 ifr.ifr_mtu = session->mtu;
1029                 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1030                         break;
1031 
1032                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get mtu=%d\n",
1033                           session->name, session->mtu);
1034                 err = 0;
1035                 break;
1036 
1037         case SIOCSIFMTU:
1038                 err = -ENXIO;
1039                 if (!(sk->sk_state & PPPOX_CONNECTED))
1040                         break;
1041 
1042                 err = -EFAULT;
1043                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1044                         break;
1045 
1046                 session->mtu = ifr.ifr_mtu;
1047 
1048                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set mtu=%d\n",
1049                           session->name, session->mtu);
1050                 err = 0;
1051                 break;
1052 
1053         case PPPIOCGMRU:
1054                 err = -ENXIO;
1055                 if (!(sk->sk_state & PPPOX_CONNECTED))
1056                         break;
1057 
1058                 err = -EFAULT;
1059                 if (put_user(session->mru, (int __user *) arg))
1060                         break;
1061 
1062                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get mru=%d\n",
1063                           session->name, session->mru);
1064                 err = 0;
1065                 break;
1066 
1067         case PPPIOCSMRU:
1068                 err = -ENXIO;
1069                 if (!(sk->sk_state & PPPOX_CONNECTED))
1070                         break;
1071 
1072                 err = -EFAULT;
1073                 if (get_user(val, (int __user *) arg))
1074                         break;
1075 
1076                 session->mru = val;
1077                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set mru=%d\n",
1078                           session->name, session->mru);
1079                 err = 0;
1080                 break;
1081 
1082         case PPPIOCGFLAGS:
1083                 err = -EFAULT;
1084                 if (put_user(ps->flags, (int __user *) arg))
1085                         break;
1086 
1087                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get flags=%d\n",
1088                           session->name, ps->flags);
1089                 err = 0;
1090                 break;
1091 
1092         case PPPIOCSFLAGS:
1093                 err = -EFAULT;
1094                 if (get_user(val, (int __user *) arg))
1095                         break;
1096                 ps->flags = val;
1097                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set flags=%d\n",
1098                           session->name, ps->flags);
1099                 err = 0;
1100                 break;
1101 
1102         case PPPIOCGL2TPSTATS:
1103                 err = -ENXIO;
1104                 if (!(sk->sk_state & PPPOX_CONNECTED))
1105                         break;
1106 
1107                 memset(&stats, 0, sizeof(stats));
1108                 stats.tunnel_id = tunnel->tunnel_id;
1109                 stats.session_id = session->session_id;
1110                 pppol2tp_copy_stats(&stats, &session->stats);
1111                 if (copy_to_user((void __user *) arg, &stats,
1112                                  sizeof(stats)))
1113                         break;
1114                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get L2TP stats\n",
1115                           session->name);
1116                 err = 0;
1117                 break;
1118 
1119         default:
1120                 err = -ENOSYS;
1121                 break;
1122         }
1123 
1124         sock_put(sk);
1125 
1126         return err;
1127 }
1128 
1129 /* Tunnel ioctl helper.
1130  *
1131  * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1132  * specifies a session_id, the session ioctl handler is called. This allows an
1133  * application to retrieve session stats via a tunnel socket.
1134  */
1135 static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
1136                                  unsigned int cmd, unsigned long arg)
1137 {
1138         int err = 0;
1139         struct sock *sk;
1140         struct pppol2tp_ioc_stats stats;
1141 
1142         l2tp_dbg(tunnel, PPPOL2TP_MSG_CONTROL,
1143                  "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n",
1144                  tunnel->name, cmd, arg);
1145 
1146         sk = tunnel->sock;
1147         sock_hold(sk);
1148 
1149         switch (cmd) {
1150         case PPPIOCGL2TPSTATS:
1151                 err = -ENXIO;
1152                 if (!(sk->sk_state & PPPOX_CONNECTED))
1153                         break;
1154 
1155                 if (copy_from_user(&stats, (void __user *) arg,
1156                                    sizeof(stats))) {
1157                         err = -EFAULT;
1158                         break;
1159                 }
1160                 if (stats.session_id != 0) {
1161                         /* resend to session ioctl handler */
1162                         struct l2tp_session *session =
1163                                 l2tp_session_find(sock_net(sk), tunnel, stats.session_id);
1164                         if (session != NULL)
1165                                 err = pppol2tp_session_ioctl(session, cmd, arg);
1166                         else
1167                                 err = -EBADR;
1168                         break;
1169                 }
1170 #ifdef CONFIG_XFRM
1171                 stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
1172 #endif
1173                 pppol2tp_copy_stats(&stats, &tunnel->stats);
1174                 if (copy_to_user((void __user *) arg, &stats, sizeof(stats))) {
1175                         err = -EFAULT;
1176                         break;
1177                 }
1178                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: get L2TP stats\n",
1179                           tunnel->name);
1180                 err = 0;
1181                 break;
1182 
1183         default:
1184                 err = -ENOSYS;
1185                 break;
1186         }
1187 
1188         sock_put(sk);
1189 
1190         return err;
1191 }
1192 
1193 /* Main ioctl() handler.
1194  * Dispatch to tunnel or session helpers depending on the socket.
1195  */
1196 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1197                           unsigned long arg)
1198 {
1199         struct sock *sk = sock->sk;
1200         struct l2tp_session *session;
1201         struct l2tp_tunnel *tunnel;
1202         struct pppol2tp_session *ps;
1203         int err;
1204 
1205         if (!sk)
1206                 return 0;
1207 
1208         err = -EBADF;
1209         if (sock_flag(sk, SOCK_DEAD) != 0)
1210                 goto end;
1211 
1212         err = -ENOTCONN;
1213         if ((sk->sk_user_data == NULL) ||
1214             (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
1215                 goto end;
1216 
1217         /* Get session context from the socket */
1218         err = -EBADF;
1219         session = pppol2tp_sock_to_session(sk);
1220         if (session == NULL)
1221                 goto end;
1222 
1223         /* Special case: if session's session_id is zero, treat ioctl as a
1224          * tunnel ioctl
1225          */
1226         ps = l2tp_session_priv(session);
1227         if ((session->session_id == 0) &&
1228             (session->peer_session_id == 0)) {
1229                 err = -EBADF;
1230                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1231                 if (tunnel == NULL)
1232                         goto end_put_sess;
1233 
1234                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
1235                 sock_put(ps->tunnel_sock);
1236                 goto end_put_sess;
1237         }
1238 
1239         err = pppol2tp_session_ioctl(session, cmd, arg);
1240 
1241 end_put_sess:
1242         sock_put(sk);
1243 end:
1244         return err;
1245 }
1246 
1247 /*****************************************************************************
1248  * setsockopt() / getsockopt() support.
1249  *
1250  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1251  * sockets. In order to control kernel tunnel features, we allow userspace to
1252  * create a special "tunnel" PPPoX socket which is used for control only.
1253  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1254  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1255  *****************************************************************************/
1256 
1257 /* Tunnel setsockopt() helper.
1258  */
1259 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1260                                       struct l2tp_tunnel *tunnel,
1261                                       int optname, int val)
1262 {
1263         int err = 0;
1264 
1265         switch (optname) {
1266         case PPPOL2TP_SO_DEBUG:
1267                 tunnel->debug = val;
1268                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: set debug=%x\n",
1269                           tunnel->name, tunnel->debug);
1270                 break;
1271 
1272         default:
1273                 err = -ENOPROTOOPT;
1274                 break;
1275         }
1276 
1277         return err;
1278 }
1279 
1280 /* Session setsockopt helper.
1281  */
1282 static int pppol2tp_session_setsockopt(struct sock *sk,
1283                                        struct l2tp_session *session,
1284                                        int optname, int val)
1285 {
1286         int err = 0;
1287         struct pppol2tp_session *ps = l2tp_session_priv(session);
1288 
1289         switch (optname) {
1290         case PPPOL2TP_SO_RECVSEQ:
1291                 if ((val != 0) && (val != 1)) {
1292                         err = -EINVAL;
1293                         break;
1294                 }
1295                 session->recv_seq = val ? -1 : 0;
1296                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1297                           "%s: set recv_seq=%d\n",
1298                           session->name, session->recv_seq);
1299                 break;
1300 
1301         case PPPOL2TP_SO_SENDSEQ:
1302                 if ((val != 0) && (val != 1)) {
1303                         err = -EINVAL;
1304                         break;
1305                 }
1306                 session->send_seq = val ? -1 : 0;
1307                 {
1308                         struct sock *ssk      = ps->sock;
1309                         struct pppox_sock *po = pppox_sk(ssk);
1310                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1311                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1312                 }
1313                 l2tp_session_set_header_len(session, session->tunnel->version);
1314                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1315                           "%s: set send_seq=%d\n",
1316                           session->name, session->send_seq);
1317                 break;
1318 
1319         case PPPOL2TP_SO_LNSMODE:
1320                 if ((val != 0) && (val != 1)) {
1321                         err = -EINVAL;
1322                         break;
1323                 }
1324                 session->lns_mode = val ? -1 : 0;
1325                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1326                           "%s: set lns_mode=%d\n",
1327                           session->name, session->lns_mode);
1328                 break;
1329 
1330         case PPPOL2TP_SO_DEBUG:
1331                 session->debug = val;
1332                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set debug=%x\n",
1333                           session->name, session->debug);
1334                 break;
1335 
1336         case PPPOL2TP_SO_REORDERTO:
1337                 session->reorder_timeout = msecs_to_jiffies(val);
1338                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1339                           "%s: set reorder_timeout=%d\n",
1340                           session->name, session->reorder_timeout);
1341                 break;
1342 
1343         default:
1344                 err = -ENOPROTOOPT;
1345                 break;
1346         }
1347 
1348         return err;
1349 }
1350 
1351 /* Main setsockopt() entry point.
1352  * Does API checks, then calls either the tunnel or session setsockopt
1353  * handler, according to whether the PPPoL2TP socket is a for a regular
1354  * session or the special tunnel type.
1355  */
1356 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1357                                char __user *optval, unsigned int optlen)
1358 {
1359         struct sock *sk = sock->sk;
1360         struct l2tp_session *session;
1361         struct l2tp_tunnel *tunnel;
1362         struct pppol2tp_session *ps;
1363         int val;
1364         int err;
1365 
1366         if (level != SOL_PPPOL2TP)
1367                 return -EINVAL;
1368 
1369         if (optlen < sizeof(int))
1370                 return -EINVAL;
1371 
1372         if (get_user(val, (int __user *)optval))
1373                 return -EFAULT;
1374 
1375         err = -ENOTCONN;
1376         if (sk->sk_user_data == NULL)
1377                 goto end;
1378 
1379         /* Get session context from the socket */
1380         err = -EBADF;
1381         session = pppol2tp_sock_to_session(sk);
1382         if (session == NULL)
1383                 goto end;
1384 
1385         /* Special case: if session_id == 0x0000, treat as operation on tunnel
1386          */
1387         ps = l2tp_session_priv(session);
1388         if ((session->session_id == 0) &&
1389             (session->peer_session_id == 0)) {
1390                 err = -EBADF;
1391                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1392                 if (tunnel == NULL)
1393                         goto end_put_sess;
1394 
1395                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1396                 sock_put(ps->tunnel_sock);
1397         } else
1398                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1399 
1400         err = 0;
1401 
1402 end_put_sess:
1403         sock_put(sk);
1404 end:
1405         return err;
1406 }
1407 
1408 /* Tunnel getsockopt helper. Called with sock locked.
1409  */
1410 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1411                                       struct l2tp_tunnel *tunnel,
1412                                       int optname, int *val)
1413 {
1414         int err = 0;
1415 
1416         switch (optname) {
1417         case PPPOL2TP_SO_DEBUG:
1418                 *val = tunnel->debug;
1419                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: get debug=%x\n",
1420                           tunnel->name, tunnel->debug);
1421                 break;
1422 
1423         default:
1424                 err = -ENOPROTOOPT;
1425                 break;
1426         }
1427 
1428         return err;
1429 }
1430 
1431 /* Session getsockopt helper. Called with sock locked.
1432  */
1433 static int pppol2tp_session_getsockopt(struct sock *sk,
1434                                        struct l2tp_session *session,
1435                                        int optname, int *val)
1436 {
1437         int err = 0;
1438 
1439         switch (optname) {
1440         case PPPOL2TP_SO_RECVSEQ:
1441                 *val = session->recv_seq;
1442                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1443                           "%s: get recv_seq=%d\n", session->name, *val);
1444                 break;
1445 
1446         case PPPOL2TP_SO_SENDSEQ:
1447                 *val = session->send_seq;
1448                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1449                           "%s: get send_seq=%d\n", session->name, *val);
1450                 break;
1451 
1452         case PPPOL2TP_SO_LNSMODE:
1453                 *val = session->lns_mode;
1454                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1455                           "%s: get lns_mode=%d\n", session->name, *val);
1456                 break;
1457 
1458         case PPPOL2TP_SO_DEBUG:
1459                 *val = session->debug;
1460                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get debug=%d\n",
1461                           session->name, *val);
1462                 break;
1463 
1464         case PPPOL2TP_SO_REORDERTO:
1465                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
1466                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1467                           "%s: get reorder_timeout=%d\n", session->name, *val);
1468                 break;
1469 
1470         default:
1471                 err = -ENOPROTOOPT;
1472         }
1473 
1474         return err;
1475 }
1476 
1477 /* Main getsockopt() entry point.
1478  * Does API checks, then calls either the tunnel or session getsockopt
1479  * handler, according to whether the PPPoX socket is a for a regular session
1480  * or the special tunnel type.
1481  */
1482 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1483                                char __user *optval, int __user *optlen)
1484 {
1485         struct sock *sk = sock->sk;
1486         struct l2tp_session *session;
1487         struct l2tp_tunnel *tunnel;
1488         int val, len;
1489         int err;
1490         struct pppol2tp_session *ps;
1491 
1492         if (level != SOL_PPPOL2TP)
1493                 return -EINVAL;
1494 
1495         if (get_user(len, optlen))
1496                 return -EFAULT;
1497 
1498         len = min_t(unsigned int, len, sizeof(int));
1499 
1500         if (len < 0)
1501                 return -EINVAL;
1502 
1503         err = -ENOTCONN;
1504         if (sk->sk_user_data == NULL)
1505                 goto end;
1506 
1507         /* Get the session context */
1508         err = -EBADF;
1509         session = pppol2tp_sock_to_session(sk);
1510         if (session == NULL)
1511                 goto end;
1512 
1513         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1514         ps = l2tp_session_priv(session);
1515         if ((session->session_id == 0) &&
1516             (session->peer_session_id == 0)) {
1517                 err = -EBADF;
1518                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1519                 if (tunnel == NULL)
1520                         goto end_put_sess;
1521 
1522                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1523                 sock_put(ps->tunnel_sock);
1524         } else
1525                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1526 
1527         err = -EFAULT;
1528         if (put_user(len, optlen))
1529                 goto end_put_sess;
1530 
1531         if (copy_to_user((void __user *) optval, &val, len))
1532                 goto end_put_sess;
1533 
1534         err = 0;
1535 
1536 end_put_sess:
1537         sock_put(sk);
1538 end:
1539         return err;
1540 }
1541 
1542 /*****************************************************************************
1543  * /proc filesystem for debug
1544  * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1545  * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1546  *****************************************************************************/
1547 
1548 static unsigned int pppol2tp_net_id;
1549 
1550 #ifdef CONFIG_PROC_FS
1551 
1552 struct pppol2tp_seq_data {
1553         struct seq_net_private p;
1554         int tunnel_idx;                 /* current tunnel */
1555         int session_idx;                /* index of session within current tunnel */
1556         struct l2tp_tunnel *tunnel;
1557         struct l2tp_session *session;   /* NULL means get next tunnel */
1558 };
1559 
1560 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1561 {
1562         for (;;) {
1563                 pd->tunnel = l2tp_tunnel_find_nth(net, pd->tunnel_idx);
1564                 pd->tunnel_idx++;
1565 
1566                 if (pd->tunnel == NULL)
1567                         break;
1568 
1569                 /* Ignore L2TPv3 tunnels */
1570                 if (pd->tunnel->version < 3)
1571                         break;
1572         }
1573 }
1574 
1575 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1576 {
1577         pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
1578         pd->session_idx++;
1579 
1580         if (pd->session == NULL) {
1581                 pd->session_idx = 0;
1582                 pppol2tp_next_tunnel(net, pd);
1583         }
1584 }
1585 
1586 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1587 {
1588         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1589         loff_t pos = *offs;
1590         struct net *net;
1591 
1592         if (!pos)
1593                 goto out;
1594 
1595         BUG_ON(m->private == NULL);
1596         pd = m->private;
1597         net = seq_file_net(m);
1598 
1599         if (pd->tunnel == NULL)
1600                 pppol2tp_next_tunnel(net, pd);
1601         else
1602                 pppol2tp_next_session(net, pd);
1603 
1604         /* NULL tunnel and session indicates end of list */
1605         if ((pd->tunnel == NULL) && (pd->session == NULL))
1606                 pd = NULL;
1607 
1608 out:
1609         return pd;
1610 }
1611 
1612 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1613 {
1614         (*pos)++;
1615         return NULL;
1616 }
1617 
1618 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1619 {
1620         /* nothing to do */
1621 }
1622 
1623 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1624 {
1625         struct l2tp_tunnel *tunnel = v;
1626 
1627         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1628                    tunnel->name,
1629                    (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N',
1630                    atomic_read(&tunnel->ref_count) - 1);
1631         seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1632                    tunnel->debug,
1633                    atomic_long_read(&tunnel->stats.tx_packets),
1634                    atomic_long_read(&tunnel->stats.tx_bytes),
1635                    atomic_long_read(&tunnel->stats.tx_errors),
1636                    atomic_long_read(&tunnel->stats.rx_packets),
1637                    atomic_long_read(&tunnel->stats.rx_bytes),
1638                    atomic_long_read(&tunnel->stats.rx_errors));
1639 }
1640 
1641 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1642 {
1643         struct l2tp_session *session = v;
1644         struct l2tp_tunnel *tunnel = session->tunnel;
1645         struct pppol2tp_session *ps = l2tp_session_priv(session);
1646         struct pppox_sock *po = pppox_sk(ps->sock);
1647         u32 ip = 0;
1648         u16 port = 0;
1649 
1650         if (tunnel->sock) {
1651                 struct inet_sock *inet = inet_sk(tunnel->sock);
1652                 ip = ntohl(inet->inet_saddr);
1653                 port = ntohs(inet->inet_sport);
1654         }
1655 
1656         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
1657                    "%04X/%04X %d %c\n",
1658                    session->name, ip, port,
1659                    tunnel->tunnel_id,
1660                    session->session_id,
1661                    tunnel->peer_tunnel_id,
1662                    session->peer_session_id,
1663                    ps->sock->sk_state,
1664                    (session == ps->sock->sk_user_data) ?
1665                    'Y' : 'N');
1666         seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
1667                    session->mtu, session->mru,
1668                    session->recv_seq ? 'R' : '-',
1669                    session->send_seq ? 'S' : '-',
1670                    session->lns_mode ? "LNS" : "LAC",
1671                    session->debug,
1672                    jiffies_to_msecs(session->reorder_timeout));
1673         seq_printf(m, "   %hu/%hu %ld/%ld/%ld %ld/%ld/%ld\n",
1674                    session->nr, session->ns,
1675                    atomic_long_read(&session->stats.tx_packets),
1676                    atomic_long_read(&session->stats.tx_bytes),
1677                    atomic_long_read(&session->stats.tx_errors),
1678                    atomic_long_read(&session->stats.rx_packets),
1679                    atomic_long_read(&session->stats.rx_bytes),
1680                    atomic_long_read(&session->stats.rx_errors));
1681 
1682         if (po)
1683                 seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
1684 }
1685 
1686 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1687 {
1688         struct pppol2tp_seq_data *pd = v;
1689 
1690         /* display header on line 1 */
1691         if (v == SEQ_START_TOKEN) {
1692                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1693                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1694                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1695                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
1696                          "dest-tid/sid state user-data-ok\n");
1697                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1698                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1699                 goto out;
1700         }
1701 
1702         /* Show the tunnel or session context.
1703          */
1704         if (pd->session == NULL)
1705                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1706         else
1707                 pppol2tp_seq_session_show(m, pd->session);
1708 
1709 out:
1710         return 0;
1711 }
1712 
1713 static const struct seq_operations pppol2tp_seq_ops = {
1714         .start          = pppol2tp_seq_start,
1715         .next           = pppol2tp_seq_next,
1716         .stop           = pppol2tp_seq_stop,
1717         .show           = pppol2tp_seq_show,
1718 };
1719 
1720 /* Called when our /proc file is opened. We allocate data for use when
1721  * iterating our tunnel / session contexts and store it in the private
1722  * data of the seq_file.
1723  */
1724 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
1725 {
1726         return seq_open_net(inode, file, &pppol2tp_seq_ops,
1727                             sizeof(struct pppol2tp_seq_data));
1728 }
1729 
1730 static const struct file_operations pppol2tp_proc_fops = {
1731         .owner          = THIS_MODULE,
1732         .open           = pppol2tp_proc_open,
1733         .read           = seq_read,
1734         .llseek         = seq_lseek,
1735         .release        = seq_release_net,
1736 };
1737 
1738 #endif /* CONFIG_PROC_FS */
1739 
1740 /*****************************************************************************
1741  * Network namespace
1742  *****************************************************************************/
1743 
1744 static __net_init int pppol2tp_init_net(struct net *net)
1745 {
1746         struct proc_dir_entry *pde;
1747         int err = 0;
1748 
1749         pde = proc_create("pppol2tp", S_IRUGO, net->proc_net,
1750                           &pppol2tp_proc_fops);
1751         if (!pde) {
1752                 err = -ENOMEM;
1753                 goto out;
1754         }
1755 
1756 out:
1757         return err;
1758 }
1759 
1760 static __net_exit void pppol2tp_exit_net(struct net *net)
1761 {
1762         remove_proc_entry("pppol2tp", net->proc_net);
1763 }
1764 
1765 static struct pernet_operations pppol2tp_net_ops = {
1766         .init = pppol2tp_init_net,
1767         .exit = pppol2tp_exit_net,
1768         .id   = &pppol2tp_net_id,
1769 };
1770 
1771 /*****************************************************************************
1772  * Init and cleanup
1773  *****************************************************************************/
1774 
1775 static const struct proto_ops pppol2tp_ops = {
1776         .family         = AF_PPPOX,
1777         .owner          = THIS_MODULE,
1778         .release        = pppol2tp_release,
1779         .bind           = sock_no_bind,
1780         .connect        = pppol2tp_connect,
1781         .socketpair     = sock_no_socketpair,
1782         .accept         = sock_no_accept,
1783         .getname        = pppol2tp_getname,
1784         .poll           = datagram_poll,
1785         .listen         = sock_no_listen,
1786         .shutdown       = sock_no_shutdown,
1787         .setsockopt     = pppol2tp_setsockopt,
1788         .getsockopt     = pppol2tp_getsockopt,
1789         .sendmsg        = pppol2tp_sendmsg,
1790         .recvmsg        = pppol2tp_recvmsg,
1791         .mmap           = sock_no_mmap,
1792         .ioctl          = pppox_ioctl,
1793 };
1794 
1795 static const struct pppox_proto pppol2tp_proto = {
1796         .create         = pppol2tp_create,
1797         .ioctl          = pppol2tp_ioctl,
1798         .owner          = THIS_MODULE,
1799 };
1800 
1801 #ifdef CONFIG_L2TP_V3
1802 
1803 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1804         .session_create = pppol2tp_session_create,
1805         .session_delete = l2tp_session_delete,
1806 };
1807 
1808 #endif /* CONFIG_L2TP_V3 */
1809 
1810 static int __init pppol2tp_init(void)
1811 {
1812         int err;
1813 
1814         err = register_pernet_device(&pppol2tp_net_ops);
1815         if (err)
1816                 goto out;
1817 
1818         err = proto_register(&pppol2tp_sk_proto, 0);
1819         if (err)
1820                 goto out_unregister_pppol2tp_pernet;
1821 
1822         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1823         if (err)
1824                 goto out_unregister_pppol2tp_proto;
1825 
1826 #ifdef CONFIG_L2TP_V3
1827         err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1828         if (err)
1829                 goto out_unregister_pppox;
1830 #endif
1831 
1832         pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1833 
1834 out:
1835         return err;
1836 
1837 #ifdef CONFIG_L2TP_V3
1838 out_unregister_pppox:
1839         unregister_pppox_proto(PX_PROTO_OL2TP);
1840 #endif
1841 out_unregister_pppol2tp_proto:
1842         proto_unregister(&pppol2tp_sk_proto);
1843 out_unregister_pppol2tp_pernet:
1844         unregister_pernet_device(&pppol2tp_net_ops);
1845         goto out;
1846 }
1847 
1848 static void __exit pppol2tp_exit(void)
1849 {
1850 #ifdef CONFIG_L2TP_V3
1851         l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1852 #endif
1853         unregister_pppox_proto(PX_PROTO_OL2TP);
1854         proto_unregister(&pppol2tp_sk_proto);
1855         unregister_pernet_device(&pppol2tp_net_ops);
1856 }
1857 
1858 module_init(pppol2tp_init);
1859 module_exit(pppol2tp_exit);
1860 
1861 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1862 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1863 MODULE_LICENSE("GPL");
1864 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1865 MODULE_ALIAS("pppox-proto-" __stringify(PX_PROTO_OL2TP));
1866 

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