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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 kiocb *iocb, struct socket *sock,
189                             struct msghdr *msg, size_t len,
190                             int flags)
191 {
192         int err;
193         struct sk_buff *skb;
194         struct sock *sk = sock->sk;
195 
196         err = -EIO;
197         if (sk->sk_state & PPPOX_BOUND)
198                 goto end;
199 
200         err = 0;
201         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
202                                 flags & MSG_DONTWAIT, &err);
203         if (!skb)
204                 goto end;
205 
206         if (len > skb->len)
207                 len = skb->len;
208         else if (len < skb->len)
209                 msg->msg_flags |= MSG_TRUNC;
210 
211         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
212         if (likely(err == 0))
213                 err = len;
214 
215         kfree_skb(skb);
216 end:
217         return err;
218 }
219 
220 static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
221 {
222         struct pppol2tp_session *ps = l2tp_session_priv(session);
223         struct sock *sk = NULL;
224 
225         /* If the socket is bound, send it in to PPP's input queue. Otherwise
226          * queue it on the session socket.
227          */
228         sk = ps->sock;
229         if (sk == NULL)
230                 goto no_sock;
231 
232         if (sk->sk_state & PPPOX_BOUND) {
233                 struct pppox_sock *po;
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                 /* We need to forget all info related to the L2TP packet
239                  * gathered in the skb as we are going to reuse the same
240                  * skb for the inner packet.
241                  * Namely we need to:
242                  * - reset xfrm (IPSec) information as it applies to
243                  *   the outer L2TP packet and not to the inner one
244                  * - release the dst to force a route lookup on the inner
245                  *   IP packet since skb->dst currently points to the dst
246                  *   of the UDP tunnel
247                  * - reset netfilter information as it doesn't apply
248                  *   to the inner packet either
249                  */
250                 secpath_reset(skb);
251                 skb_dst_drop(skb);
252                 nf_reset(skb);
253 
254                 po = pppox_sk(sk);
255                 ppp_input(&po->chan, skb);
256         } else {
257                 l2tp_dbg(session, PPPOL2TP_MSG_DATA,
258                          "%s: recv %d byte data frame, passing to L2TP socket\n",
259                          session->name, data_len);
260 
261                 if (sock_queue_rcv_skb(sk, skb) < 0) {
262                         atomic_long_inc(&session->stats.rx_errors);
263                         kfree_skb(skb);
264                 }
265         }
266 
267         return;
268 
269 no_sock:
270         l2tp_info(session, PPPOL2TP_MSG_DATA, "%s: no socket\n", session->name);
271         kfree_skb(skb);
272 }
273 
274 static void pppol2tp_session_sock_hold(struct l2tp_session *session)
275 {
276         struct pppol2tp_session *ps = l2tp_session_priv(session);
277 
278         if (ps->sock)
279                 sock_hold(ps->sock);
280 }
281 
282 static void pppol2tp_session_sock_put(struct l2tp_session *session)
283 {
284         struct pppol2tp_session *ps = l2tp_session_priv(session);
285 
286         if (ps->sock)
287                 sock_put(ps->sock);
288 }
289 
290 /************************************************************************
291  * Transmit handling
292  ***********************************************************************/
293 
294 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
295  * when a user application does a sendmsg() on the session socket. L2TP and
296  * PPP headers must be inserted into the user's data.
297  */
298 static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
299                             size_t total_len)
300 {
301         static const unsigned char ppph[2] = { 0xff, 0x03 };
302         struct sock *sk = sock->sk;
303         struct sk_buff *skb;
304         int error;
305         struct l2tp_session *session;
306         struct l2tp_tunnel *tunnel;
307         struct pppol2tp_session *ps;
308         int uhlen;
309 
310         error = -ENOTCONN;
311         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
312                 goto error;
313 
314         /* Get session and tunnel contexts */
315         error = -EBADF;
316         session = pppol2tp_sock_to_session(sk);
317         if (session == NULL)
318                 goto error;
319 
320         ps = l2tp_session_priv(session);
321         tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
322         if (tunnel == NULL)
323                 goto error_put_sess;
324 
325         uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
326 
327         /* Allocate a socket buffer */
328         error = -ENOMEM;
329         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
330                            uhlen + session->hdr_len +
331                            sizeof(ppph) + total_len,
332                            0, GFP_KERNEL);
333         if (!skb)
334                 goto error_put_sess_tun;
335 
336         /* Reserve space for headers. */
337         skb_reserve(skb, NET_SKB_PAD);
338         skb_reset_network_header(skb);
339         skb_reserve(skb, sizeof(struct iphdr));
340         skb_reset_transport_header(skb);
341         skb_reserve(skb, uhlen);
342 
343         /* Add PPP header */
344         skb->data[0] = ppph[0];
345         skb->data[1] = ppph[1];
346         skb_put(skb, 2);
347 
348         /* Copy user data into skb */
349         error = memcpy_fromiovec(skb_put(skb, total_len), m->msg_iov,
350                                  total_len);
351         if (error < 0) {
352                 kfree_skb(skb);
353                 goto error_put_sess_tun;
354         }
355 
356         local_bh_disable();
357         l2tp_xmit_skb(session, skb, session->hdr_len);
358         local_bh_enable();
359 
360         sock_put(ps->tunnel_sock);
361         sock_put(sk);
362 
363         return total_len;
364 
365 error_put_sess_tun:
366         sock_put(ps->tunnel_sock);
367 error_put_sess:
368         sock_put(sk);
369 error:
370         return error;
371 }
372 
373 /* Transmit function called by generic PPP driver.  Sends PPP frame
374  * over PPPoL2TP socket.
375  *
376  * This is almost the same as pppol2tp_sendmsg(), but rather than
377  * being called with a msghdr from userspace, it is called with a skb
378  * from the kernel.
379  *
380  * The supplied skb from ppp doesn't have enough headroom for the
381  * insertion of L2TP, UDP and IP headers so we need to allocate more
382  * headroom in the skb. This will create a cloned skb. But we must be
383  * careful in the error case because the caller will expect to free
384  * the skb it supplied, not our cloned skb. So we take care to always
385  * leave the original skb unfreed if we return an error.
386  */
387 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
388 {
389         static const u8 ppph[2] = { 0xff, 0x03 };
390         struct sock *sk = (struct sock *) chan->private;
391         struct sock *sk_tun;
392         struct l2tp_session *session;
393         struct l2tp_tunnel *tunnel;
394         struct pppol2tp_session *ps;
395         int uhlen, headroom;
396 
397         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
398                 goto abort;
399 
400         /* Get session and tunnel contexts from the socket */
401         session = pppol2tp_sock_to_session(sk);
402         if (session == NULL)
403                 goto abort;
404 
405         ps = l2tp_session_priv(session);
406         sk_tun = ps->tunnel_sock;
407         if (sk_tun == NULL)
408                 goto abort_put_sess;
409         tunnel = l2tp_sock_to_tunnel(sk_tun);
410         if (tunnel == NULL)
411                 goto abort_put_sess;
412 
413         uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
414         headroom = NET_SKB_PAD +
415                    sizeof(struct iphdr) + /* IP header */
416                    uhlen +              /* UDP header (if L2TP_ENCAPTYPE_UDP) */
417                    session->hdr_len +   /* L2TP header */
418                    sizeof(ppph);        /* PPP header */
419         if (skb_cow_head(skb, headroom))
420                 goto abort_put_sess_tun;
421 
422         /* Setup PPP header */
423         __skb_push(skb, sizeof(ppph));
424         skb->data[0] = ppph[0];
425         skb->data[1] = ppph[1];
426 
427         local_bh_disable();
428         l2tp_xmit_skb(session, skb, session->hdr_len);
429         local_bh_enable();
430 
431         sock_put(sk_tun);
432         sock_put(sk);
433         return 1;
434 
435 abort_put_sess_tun:
436         sock_put(sk_tun);
437 abort_put_sess:
438         sock_put(sk);
439 abort:
440         /* Free the original skb */
441         kfree_skb(skb);
442         return 1;
443 }
444 
445 /*****************************************************************************
446  * Session (and tunnel control) socket create/destroy.
447  *****************************************************************************/
448 
449 /* Called by l2tp_core when a session socket is being closed.
450  */
451 static void pppol2tp_session_close(struct l2tp_session *session)
452 {
453         struct pppol2tp_session *ps = l2tp_session_priv(session);
454         struct sock *sk = ps->sock;
455         struct socket *sock = sk->sk_socket;
456 
457         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
458 
459         if (sock) {
460                 inet_shutdown(sock, 2);
461                 /* Don't let the session go away before our socket does */
462                 l2tp_session_inc_refcount(session);
463         }
464 }
465 
466 /* Really kill the session socket. (Called from sock_put() if
467  * refcnt == 0.)
468  */
469 static void pppol2tp_session_destruct(struct sock *sk)
470 {
471         struct l2tp_session *session = sk->sk_user_data;
472         if (session) {
473                 sk->sk_user_data = NULL;
474                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
475                 l2tp_session_dec_refcount(session);
476         }
477 }
478 
479 /* Called when the PPPoX socket (session) is closed.
480  */
481 static int pppol2tp_release(struct socket *sock)
482 {
483         struct sock *sk = sock->sk;
484         struct l2tp_session *session;
485         int error;
486 
487         if (!sk)
488                 return 0;
489 
490         error = -EBADF;
491         lock_sock(sk);
492         if (sock_flag(sk, SOCK_DEAD) != 0)
493                 goto error;
494 
495         pppox_unbind_sock(sk);
496 
497         /* Signal the death of the socket. */
498         sk->sk_state = PPPOX_DEAD;
499         sock_orphan(sk);
500         sock->sk = NULL;
501 
502         session = pppol2tp_sock_to_session(sk);
503 
504         /* Purge any queued data */
505         if (session != NULL) {
506                 __l2tp_session_unhash(session);
507                 l2tp_session_queue_purge(session);
508                 sock_put(sk);
509         }
510         skb_queue_purge(&sk->sk_receive_queue);
511         skb_queue_purge(&sk->sk_write_queue);
512 
513         release_sock(sk);
514 
515         /* This will delete the session context via
516          * pppol2tp_session_destruct() if the socket's refcnt drops to
517          * zero.
518          */
519         sock_put(sk);
520 
521         return 0;
522 
523 error:
524         release_sock(sk);
525         return error;
526 }
527 
528 static struct proto pppol2tp_sk_proto = {
529         .name     = "PPPOL2TP",
530         .owner    = THIS_MODULE,
531         .obj_size = sizeof(struct pppox_sock),
532 };
533 
534 static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
535 {
536         int rc;
537 
538         rc = l2tp_udp_encap_recv(sk, skb);
539         if (rc)
540                 kfree_skb(skb);
541 
542         return NET_RX_SUCCESS;
543 }
544 
545 /* socket() handler. Initialize a new struct sock.
546  */
547 static int pppol2tp_create(struct net *net, struct socket *sock)
548 {
549         int error = -ENOMEM;
550         struct sock *sk;
551 
552         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
553         if (!sk)
554                 goto out;
555 
556         sock_init_data(sock, sk);
557 
558         sock->state  = SS_UNCONNECTED;
559         sock->ops    = &pppol2tp_ops;
560 
561         sk->sk_backlog_rcv = pppol2tp_backlog_recv;
562         sk->sk_protocol    = PX_PROTO_OL2TP;
563         sk->sk_family      = PF_PPPOX;
564         sk->sk_state       = PPPOX_NONE;
565         sk->sk_type        = SOCK_STREAM;
566         sk->sk_destruct    = pppol2tp_session_destruct;
567 
568         error = 0;
569 
570 out:
571         return error;
572 }
573 
574 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
575 static void pppol2tp_show(struct seq_file *m, void *arg)
576 {
577         struct l2tp_session *session = arg;
578         struct pppol2tp_session *ps = l2tp_session_priv(session);
579 
580         if (ps) {
581                 struct pppox_sock *po = pppox_sk(ps->sock);
582                 if (po)
583                         seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
584         }
585 }
586 #endif
587 
588 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
589  */
590 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
591                             int sockaddr_len, int flags)
592 {
593         struct sock *sk = sock->sk;
594         struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
595         struct pppox_sock *po = pppox_sk(sk);
596         struct l2tp_session *session = NULL;
597         struct l2tp_tunnel *tunnel;
598         struct pppol2tp_session *ps;
599         struct dst_entry *dst;
600         struct l2tp_session_cfg cfg = { 0, };
601         int error = 0;
602         u32 tunnel_id, peer_tunnel_id;
603         u32 session_id, peer_session_id;
604         int ver = 2;
605         int fd;
606 
607         lock_sock(sk);
608 
609         error = -EINVAL;
610         if (sp->sa_protocol != PX_PROTO_OL2TP)
611                 goto end;
612 
613         /* Check for already bound sockets */
614         error = -EBUSY;
615         if (sk->sk_state & PPPOX_CONNECTED)
616                 goto end;
617 
618         /* We don't supporting rebinding anyway */
619         error = -EALREADY;
620         if (sk->sk_user_data)
621                 goto end; /* socket is already attached */
622 
623         /* Get params from socket address. Handle L2TPv2 and L2TPv3.
624          * This is nasty because there are different sockaddr_pppol2tp
625          * structs for L2TPv2, L2TPv3, over IPv4 and IPv6. We use
626          * the sockaddr size to determine which structure the caller
627          * is using.
628          */
629         peer_tunnel_id = 0;
630         if (sockaddr_len == sizeof(struct sockaddr_pppol2tp)) {
631                 fd = sp->pppol2tp.fd;
632                 tunnel_id = sp->pppol2tp.s_tunnel;
633                 peer_tunnel_id = sp->pppol2tp.d_tunnel;
634                 session_id = sp->pppol2tp.s_session;
635                 peer_session_id = sp->pppol2tp.d_session;
636         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3)) {
637                 struct sockaddr_pppol2tpv3 *sp3 =
638                         (struct sockaddr_pppol2tpv3 *) sp;
639                 ver = 3;
640                 fd = sp3->pppol2tp.fd;
641                 tunnel_id = sp3->pppol2tp.s_tunnel;
642                 peer_tunnel_id = sp3->pppol2tp.d_tunnel;
643                 session_id = sp3->pppol2tp.s_session;
644                 peer_session_id = sp3->pppol2tp.d_session;
645         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpin6)) {
646                 struct sockaddr_pppol2tpin6 *sp6 =
647                         (struct sockaddr_pppol2tpin6 *) sp;
648                 fd = sp6->pppol2tp.fd;
649                 tunnel_id = sp6->pppol2tp.s_tunnel;
650                 peer_tunnel_id = sp6->pppol2tp.d_tunnel;
651                 session_id = sp6->pppol2tp.s_session;
652                 peer_session_id = sp6->pppol2tp.d_session;
653         } else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3in6)) {
654                 struct sockaddr_pppol2tpv3in6 *sp6 =
655                         (struct sockaddr_pppol2tpv3in6 *) sp;
656                 ver = 3;
657                 fd = sp6->pppol2tp.fd;
658                 tunnel_id = sp6->pppol2tp.s_tunnel;
659                 peer_tunnel_id = sp6->pppol2tp.d_tunnel;
660                 session_id = sp6->pppol2tp.s_session;
661                 peer_session_id = sp6->pppol2tp.d_session;
662         } else {
663                 error = -EINVAL;
664                 goto end; /* bad socket address */
665         }
666 
667         /* Don't bind if tunnel_id is 0 */
668         error = -EINVAL;
669         if (tunnel_id == 0)
670                 goto end;
671 
672         tunnel = l2tp_tunnel_find(sock_net(sk), tunnel_id);
673 
674         /* Special case: create tunnel context if session_id and
675          * peer_session_id is 0. Otherwise look up tunnel using supplied
676          * tunnel id.
677          */
678         if ((session_id == 0) && (peer_session_id == 0)) {
679                 if (tunnel == NULL) {
680                         struct l2tp_tunnel_cfg tcfg = {
681                                 .encap = L2TP_ENCAPTYPE_UDP,
682                                 .debug = 0,
683                         };
684                         error = l2tp_tunnel_create(sock_net(sk), fd, ver, tunnel_id, peer_tunnel_id, &tcfg, &tunnel);
685                         if (error < 0)
686                                 goto end;
687                 }
688         } else {
689                 /* Error if we can't find the tunnel */
690                 error = -ENOENT;
691                 if (tunnel == NULL)
692                         goto end;
693 
694                 /* Error if socket is not prepped */
695                 if (tunnel->sock == NULL)
696                         goto end;
697         }
698 
699         if (tunnel->recv_payload_hook == NULL)
700                 tunnel->recv_payload_hook = pppol2tp_recv_payload_hook;
701 
702         if (tunnel->peer_tunnel_id == 0)
703                 tunnel->peer_tunnel_id = peer_tunnel_id;
704 
705         /* Create session if it doesn't already exist. We handle the
706          * case where a session was previously created by the netlink
707          * interface by checking that the session doesn't already have
708          * a socket and its tunnel socket are what we expect. If any
709          * of those checks fail, return EEXIST to the caller.
710          */
711         session = l2tp_session_find(sock_net(sk), tunnel, session_id);
712         if (session == NULL) {
713                 /* Default MTU must allow space for UDP/L2TP/PPP
714                  * headers.
715                  */
716                 cfg.mtu = cfg.mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
717 
718                 /* Allocate and initialize a new session context. */
719                 session = l2tp_session_create(sizeof(struct pppol2tp_session),
720                                               tunnel, session_id,
721                                               peer_session_id, &cfg);
722                 if (session == NULL) {
723                         error = -ENOMEM;
724                         goto end;
725                 }
726         } else {
727                 ps = l2tp_session_priv(session);
728                 error = -EEXIST;
729                 if (ps->sock != NULL)
730                         goto end;
731 
732                 /* consistency checks */
733                 if (ps->tunnel_sock != tunnel->sock)
734                         goto end;
735         }
736 
737         /* Associate session with its PPPoL2TP socket */
738         ps = l2tp_session_priv(session);
739         ps->owner            = current->pid;
740         ps->sock             = sk;
741         ps->tunnel_sock = tunnel->sock;
742 
743         session->recv_skb       = pppol2tp_recv;
744         session->session_close  = pppol2tp_session_close;
745 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
746         session->show           = pppol2tp_show;
747 #endif
748 
749         /* We need to know each time a skb is dropped from the reorder
750          * queue.
751          */
752         session->ref = pppol2tp_session_sock_hold;
753         session->deref = pppol2tp_session_sock_put;
754 
755         /* If PMTU discovery was enabled, use the MTU that was discovered */
756         dst = sk_dst_get(tunnel->sock);
757         if (dst != NULL) {
758                 u32 pmtu = dst_mtu(__sk_dst_get(tunnel->sock));
759                 if (pmtu != 0)
760                         session->mtu = session->mru = pmtu -
761                                 PPPOL2TP_HEADER_OVERHEAD;
762                 dst_release(dst);
763         }
764 
765         /* Special case: if source & dest session_id == 0x0000, this
766          * socket is being created to manage the tunnel. Just set up
767          * the internal context for use by ioctl() and sockopt()
768          * handlers.
769          */
770         if ((session->session_id == 0) &&
771             (session->peer_session_id == 0)) {
772                 error = 0;
773                 goto out_no_ppp;
774         }
775 
776         /* The only header we need to worry about is the L2TP
777          * header. This size is different depending on whether
778          * sequence numbers are enabled for the data channel.
779          */
780         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
781 
782         po->chan.private = sk;
783         po->chan.ops     = &pppol2tp_chan_ops;
784         po->chan.mtu     = session->mtu;
785 
786         error = ppp_register_net_channel(sock_net(sk), &po->chan);
787         if (error)
788                 goto end;
789 
790 out_no_ppp:
791         /* This is how we get the session context from the socket. */
792         sk->sk_user_data = session;
793         sk->sk_state = PPPOX_CONNECTED;
794         l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: created\n",
795                   session->name);
796 
797 end:
798         release_sock(sk);
799 
800         return error;
801 }
802 
803 #ifdef CONFIG_L2TP_V3
804 
805 /* Called when creating sessions via the netlink interface.
806  */
807 static int pppol2tp_session_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
808 {
809         int error;
810         struct l2tp_tunnel *tunnel;
811         struct l2tp_session *session;
812         struct pppol2tp_session *ps;
813 
814         tunnel = l2tp_tunnel_find(net, tunnel_id);
815 
816         /* Error if we can't find the tunnel */
817         error = -ENOENT;
818         if (tunnel == NULL)
819                 goto out;
820 
821         /* Error if tunnel socket is not prepped */
822         if (tunnel->sock == NULL)
823                 goto out;
824 
825         /* Check that this session doesn't already exist */
826         error = -EEXIST;
827         session = l2tp_session_find(net, tunnel, session_id);
828         if (session != NULL)
829                 goto out;
830 
831         /* Default MTU values. */
832         if (cfg->mtu == 0)
833                 cfg->mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
834         if (cfg->mru == 0)
835                 cfg->mru = cfg->mtu;
836 
837         /* Allocate and initialize a new session context. */
838         error = -ENOMEM;
839         session = l2tp_session_create(sizeof(struct pppol2tp_session),
840                                       tunnel, session_id,
841                                       peer_session_id, cfg);
842         if (session == NULL)
843                 goto out;
844 
845         ps = l2tp_session_priv(session);
846         ps->tunnel_sock = tunnel->sock;
847 
848         l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: created\n",
849                   session->name);
850 
851         error = 0;
852 
853 out:
854         return error;
855 }
856 
857 #endif /* CONFIG_L2TP_V3 */
858 
859 /* getname() support.
860  */
861 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
862                             int *usockaddr_len, int peer)
863 {
864         int len = 0;
865         int error = 0;
866         struct l2tp_session *session;
867         struct l2tp_tunnel *tunnel;
868         struct sock *sk = sock->sk;
869         struct inet_sock *inet;
870         struct pppol2tp_session *pls;
871 
872         error = -ENOTCONN;
873         if (sk == NULL)
874                 goto end;
875         if (sk->sk_state != PPPOX_CONNECTED)
876                 goto end;
877 
878         error = -EBADF;
879         session = pppol2tp_sock_to_session(sk);
880         if (session == NULL)
881                 goto end;
882 
883         pls = l2tp_session_priv(session);
884         tunnel = l2tp_sock_to_tunnel(pls->tunnel_sock);
885         if (tunnel == NULL) {
886                 error = -EBADF;
887                 goto end_put_sess;
888         }
889 
890         inet = inet_sk(tunnel->sock);
891         if ((tunnel->version == 2) && (tunnel->sock->sk_family == AF_INET)) {
892                 struct sockaddr_pppol2tp sp;
893                 len = sizeof(sp);
894                 memset(&sp, 0, len);
895                 sp.sa_family    = AF_PPPOX;
896                 sp.sa_protocol  = PX_PROTO_OL2TP;
897                 sp.pppol2tp.fd  = tunnel->fd;
898                 sp.pppol2tp.pid = pls->owner;
899                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
900                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
901                 sp.pppol2tp.s_session = session->session_id;
902                 sp.pppol2tp.d_session = session->peer_session_id;
903                 sp.pppol2tp.addr.sin_family = AF_INET;
904                 sp.pppol2tp.addr.sin_port = inet->inet_dport;
905                 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
906                 memcpy(uaddr, &sp, len);
907 #if IS_ENABLED(CONFIG_IPV6)
908         } else if ((tunnel->version == 2) &&
909                    (tunnel->sock->sk_family == AF_INET6)) {
910                 struct sockaddr_pppol2tpin6 sp;
911 
912                 len = sizeof(sp);
913                 memset(&sp, 0, len);
914                 sp.sa_family    = AF_PPPOX;
915                 sp.sa_protocol  = PX_PROTO_OL2TP;
916                 sp.pppol2tp.fd  = tunnel->fd;
917                 sp.pppol2tp.pid = pls->owner;
918                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
919                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
920                 sp.pppol2tp.s_session = session->session_id;
921                 sp.pppol2tp.d_session = session->peer_session_id;
922                 sp.pppol2tp.addr.sin6_family = AF_INET6;
923                 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
924                 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
925                        sizeof(tunnel->sock->sk_v6_daddr));
926                 memcpy(uaddr, &sp, len);
927         } else if ((tunnel->version == 3) &&
928                    (tunnel->sock->sk_family == AF_INET6)) {
929                 struct sockaddr_pppol2tpv3in6 sp;
930 
931                 len = sizeof(sp);
932                 memset(&sp, 0, len);
933                 sp.sa_family    = AF_PPPOX;
934                 sp.sa_protocol  = PX_PROTO_OL2TP;
935                 sp.pppol2tp.fd  = tunnel->fd;
936                 sp.pppol2tp.pid = pls->owner;
937                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
938                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
939                 sp.pppol2tp.s_session = session->session_id;
940                 sp.pppol2tp.d_session = session->peer_session_id;
941                 sp.pppol2tp.addr.sin6_family = AF_INET6;
942                 sp.pppol2tp.addr.sin6_port = inet->inet_dport;
943                 memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
944                        sizeof(tunnel->sock->sk_v6_daddr));
945                 memcpy(uaddr, &sp, len);
946 #endif
947         } else if (tunnel->version == 3) {
948                 struct sockaddr_pppol2tpv3 sp;
949                 len = sizeof(sp);
950                 memset(&sp, 0, len);
951                 sp.sa_family    = AF_PPPOX;
952                 sp.sa_protocol  = PX_PROTO_OL2TP;
953                 sp.pppol2tp.fd  = tunnel->fd;
954                 sp.pppol2tp.pid = pls->owner;
955                 sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
956                 sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
957                 sp.pppol2tp.s_session = session->session_id;
958                 sp.pppol2tp.d_session = session->peer_session_id;
959                 sp.pppol2tp.addr.sin_family = AF_INET;
960                 sp.pppol2tp.addr.sin_port = inet->inet_dport;
961                 sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
962                 memcpy(uaddr, &sp, len);
963         }
964 
965         *usockaddr_len = len;
966 
967         sock_put(pls->tunnel_sock);
968 end_put_sess:
969         sock_put(sk);
970         error = 0;
971 
972 end:
973         return error;
974 }
975 
976 /****************************************************************************
977  * ioctl() handlers.
978  *
979  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
980  * sockets. However, in order to control kernel tunnel features, we allow
981  * userspace to create a special "tunnel" PPPoX socket which is used for
982  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
983  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
984  * calls.
985  ****************************************************************************/
986 
987 static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
988                                 struct l2tp_stats *stats)
989 {
990         dest->tx_packets = atomic_long_read(&stats->tx_packets);
991         dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
992         dest->tx_errors = atomic_long_read(&stats->tx_errors);
993         dest->rx_packets = atomic_long_read(&stats->rx_packets);
994         dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
995         dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
996         dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
997         dest->rx_errors = atomic_long_read(&stats->rx_errors);
998 }
999 
1000 /* Session ioctl helper.
1001  */
1002 static int pppol2tp_session_ioctl(struct l2tp_session *session,
1003                                   unsigned int cmd, unsigned long arg)
1004 {
1005         struct ifreq ifr;
1006         int err = 0;
1007         struct sock *sk;
1008         int val = (int) arg;
1009         struct pppol2tp_session *ps = l2tp_session_priv(session);
1010         struct l2tp_tunnel *tunnel = session->tunnel;
1011         struct pppol2tp_ioc_stats stats;
1012 
1013         l2tp_dbg(session, PPPOL2TP_MSG_CONTROL,
1014                  "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
1015                  session->name, cmd, arg);
1016 
1017         sk = ps->sock;
1018         sock_hold(sk);
1019 
1020         switch (cmd) {
1021         case SIOCGIFMTU:
1022                 err = -ENXIO;
1023                 if (!(sk->sk_state & PPPOX_CONNECTED))
1024                         break;
1025 
1026                 err = -EFAULT;
1027                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1028                         break;
1029                 ifr.ifr_mtu = session->mtu;
1030                 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1031                         break;
1032 
1033                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get mtu=%d\n",
1034                           session->name, session->mtu);
1035                 err = 0;
1036                 break;
1037 
1038         case SIOCSIFMTU:
1039                 err = -ENXIO;
1040                 if (!(sk->sk_state & PPPOX_CONNECTED))
1041                         break;
1042 
1043                 err = -EFAULT;
1044                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1045                         break;
1046 
1047                 session->mtu = ifr.ifr_mtu;
1048 
1049                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set mtu=%d\n",
1050                           session->name, session->mtu);
1051                 err = 0;
1052                 break;
1053 
1054         case PPPIOCGMRU:
1055                 err = -ENXIO;
1056                 if (!(sk->sk_state & PPPOX_CONNECTED))
1057                         break;
1058 
1059                 err = -EFAULT;
1060                 if (put_user(session->mru, (int __user *) arg))
1061                         break;
1062 
1063                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get mru=%d\n",
1064                           session->name, session->mru);
1065                 err = 0;
1066                 break;
1067 
1068         case PPPIOCSMRU:
1069                 err = -ENXIO;
1070                 if (!(sk->sk_state & PPPOX_CONNECTED))
1071                         break;
1072 
1073                 err = -EFAULT;
1074                 if (get_user(val, (int __user *) arg))
1075                         break;
1076 
1077                 session->mru = val;
1078                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set mru=%d\n",
1079                           session->name, session->mru);
1080                 err = 0;
1081                 break;
1082 
1083         case PPPIOCGFLAGS:
1084                 err = -EFAULT;
1085                 if (put_user(ps->flags, (int __user *) arg))
1086                         break;
1087 
1088                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get flags=%d\n",
1089                           session->name, ps->flags);
1090                 err = 0;
1091                 break;
1092 
1093         case PPPIOCSFLAGS:
1094                 err = -EFAULT;
1095                 if (get_user(val, (int __user *) arg))
1096                         break;
1097                 ps->flags = val;
1098                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set flags=%d\n",
1099                           session->name, ps->flags);
1100                 err = 0;
1101                 break;
1102 
1103         case PPPIOCGL2TPSTATS:
1104                 err = -ENXIO;
1105                 if (!(sk->sk_state & PPPOX_CONNECTED))
1106                         break;
1107 
1108                 memset(&stats, 0, sizeof(stats));
1109                 stats.tunnel_id = tunnel->tunnel_id;
1110                 stats.session_id = session->session_id;
1111                 pppol2tp_copy_stats(&stats, &session->stats);
1112                 if (copy_to_user((void __user *) arg, &stats,
1113                                  sizeof(stats)))
1114                         break;
1115                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get L2TP stats\n",
1116                           session->name);
1117                 err = 0;
1118                 break;
1119 
1120         default:
1121                 err = -ENOSYS;
1122                 break;
1123         }
1124 
1125         sock_put(sk);
1126 
1127         return err;
1128 }
1129 
1130 /* Tunnel ioctl helper.
1131  *
1132  * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1133  * specifies a session_id, the session ioctl handler is called. This allows an
1134  * application to retrieve session stats via a tunnel socket.
1135  */
1136 static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
1137                                  unsigned int cmd, unsigned long arg)
1138 {
1139         int err = 0;
1140         struct sock *sk;
1141         struct pppol2tp_ioc_stats stats;
1142 
1143         l2tp_dbg(tunnel, PPPOL2TP_MSG_CONTROL,
1144                  "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n",
1145                  tunnel->name, cmd, arg);
1146 
1147         sk = tunnel->sock;
1148         sock_hold(sk);
1149 
1150         switch (cmd) {
1151         case PPPIOCGL2TPSTATS:
1152                 err = -ENXIO;
1153                 if (!(sk->sk_state & PPPOX_CONNECTED))
1154                         break;
1155 
1156                 if (copy_from_user(&stats, (void __user *) arg,
1157                                    sizeof(stats))) {
1158                         err = -EFAULT;
1159                         break;
1160                 }
1161                 if (stats.session_id != 0) {
1162                         /* resend to session ioctl handler */
1163                         struct l2tp_session *session =
1164                                 l2tp_session_find(sock_net(sk), tunnel, stats.session_id);
1165                         if (session != NULL)
1166                                 err = pppol2tp_session_ioctl(session, cmd, arg);
1167                         else
1168                                 err = -EBADR;
1169                         break;
1170                 }
1171 #ifdef CONFIG_XFRM
1172                 stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
1173 #endif
1174                 pppol2tp_copy_stats(&stats, &tunnel->stats);
1175                 if (copy_to_user((void __user *) arg, &stats, sizeof(stats))) {
1176                         err = -EFAULT;
1177                         break;
1178                 }
1179                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: get L2TP stats\n",
1180                           tunnel->name);
1181                 err = 0;
1182                 break;
1183 
1184         default:
1185                 err = -ENOSYS;
1186                 break;
1187         }
1188 
1189         sock_put(sk);
1190 
1191         return err;
1192 }
1193 
1194 /* Main ioctl() handler.
1195  * Dispatch to tunnel or session helpers depending on the socket.
1196  */
1197 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
1198                           unsigned long arg)
1199 {
1200         struct sock *sk = sock->sk;
1201         struct l2tp_session *session;
1202         struct l2tp_tunnel *tunnel;
1203         struct pppol2tp_session *ps;
1204         int err;
1205 
1206         if (!sk)
1207                 return 0;
1208 
1209         err = -EBADF;
1210         if (sock_flag(sk, SOCK_DEAD) != 0)
1211                 goto end;
1212 
1213         err = -ENOTCONN;
1214         if ((sk->sk_user_data == NULL) ||
1215             (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
1216                 goto end;
1217 
1218         /* Get session context from the socket */
1219         err = -EBADF;
1220         session = pppol2tp_sock_to_session(sk);
1221         if (session == NULL)
1222                 goto end;
1223 
1224         /* Special case: if session's session_id is zero, treat ioctl as a
1225          * tunnel ioctl
1226          */
1227         ps = l2tp_session_priv(session);
1228         if ((session->session_id == 0) &&
1229             (session->peer_session_id == 0)) {
1230                 err = -EBADF;
1231                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1232                 if (tunnel == NULL)
1233                         goto end_put_sess;
1234 
1235                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
1236                 sock_put(ps->tunnel_sock);
1237                 goto end_put_sess;
1238         }
1239 
1240         err = pppol2tp_session_ioctl(session, cmd, arg);
1241 
1242 end_put_sess:
1243         sock_put(sk);
1244 end:
1245         return err;
1246 }
1247 
1248 /*****************************************************************************
1249  * setsockopt() / getsockopt() support.
1250  *
1251  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1252  * sockets. In order to control kernel tunnel features, we allow userspace to
1253  * create a special "tunnel" PPPoX socket which is used for control only.
1254  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
1255  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
1256  *****************************************************************************/
1257 
1258 /* Tunnel setsockopt() helper.
1259  */
1260 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
1261                                       struct l2tp_tunnel *tunnel,
1262                                       int optname, int val)
1263 {
1264         int err = 0;
1265 
1266         switch (optname) {
1267         case PPPOL2TP_SO_DEBUG:
1268                 tunnel->debug = val;
1269                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: set debug=%x\n",
1270                           tunnel->name, tunnel->debug);
1271                 break;
1272 
1273         default:
1274                 err = -ENOPROTOOPT;
1275                 break;
1276         }
1277 
1278         return err;
1279 }
1280 
1281 /* Session setsockopt helper.
1282  */
1283 static int pppol2tp_session_setsockopt(struct sock *sk,
1284                                        struct l2tp_session *session,
1285                                        int optname, int val)
1286 {
1287         int err = 0;
1288         struct pppol2tp_session *ps = l2tp_session_priv(session);
1289 
1290         switch (optname) {
1291         case PPPOL2TP_SO_RECVSEQ:
1292                 if ((val != 0) && (val != 1)) {
1293                         err = -EINVAL;
1294                         break;
1295                 }
1296                 session->recv_seq = val ? -1 : 0;
1297                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1298                           "%s: set recv_seq=%d\n",
1299                           session->name, session->recv_seq);
1300                 break;
1301 
1302         case PPPOL2TP_SO_SENDSEQ:
1303                 if ((val != 0) && (val != 1)) {
1304                         err = -EINVAL;
1305                         break;
1306                 }
1307                 session->send_seq = val ? -1 : 0;
1308                 {
1309                         struct sock *ssk      = ps->sock;
1310                         struct pppox_sock *po = pppox_sk(ssk);
1311                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
1312                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1313                 }
1314                 l2tp_session_set_header_len(session, session->tunnel->version);
1315                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1316                           "%s: set send_seq=%d\n",
1317                           session->name, session->send_seq);
1318                 break;
1319 
1320         case PPPOL2TP_SO_LNSMODE:
1321                 if ((val != 0) && (val != 1)) {
1322                         err = -EINVAL;
1323                         break;
1324                 }
1325                 session->lns_mode = val ? -1 : 0;
1326                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1327                           "%s: set lns_mode=%d\n",
1328                           session->name, session->lns_mode);
1329                 break;
1330 
1331         case PPPOL2TP_SO_DEBUG:
1332                 session->debug = val;
1333                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: set debug=%x\n",
1334                           session->name, session->debug);
1335                 break;
1336 
1337         case PPPOL2TP_SO_REORDERTO:
1338                 session->reorder_timeout = msecs_to_jiffies(val);
1339                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1340                           "%s: set reorder_timeout=%d\n",
1341                           session->name, session->reorder_timeout);
1342                 break;
1343 
1344         default:
1345                 err = -ENOPROTOOPT;
1346                 break;
1347         }
1348 
1349         return err;
1350 }
1351 
1352 /* Main setsockopt() entry point.
1353  * Does API checks, then calls either the tunnel or session setsockopt
1354  * handler, according to whether the PPPoL2TP socket is a for a regular
1355  * session or the special tunnel type.
1356  */
1357 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
1358                                char __user *optval, unsigned int optlen)
1359 {
1360         struct sock *sk = sock->sk;
1361         struct l2tp_session *session;
1362         struct l2tp_tunnel *tunnel;
1363         struct pppol2tp_session *ps;
1364         int val;
1365         int err;
1366 
1367         if (level != SOL_PPPOL2TP)
1368                 return -EINVAL;
1369 
1370         if (optlen < sizeof(int))
1371                 return -EINVAL;
1372 
1373         if (get_user(val, (int __user *)optval))
1374                 return -EFAULT;
1375 
1376         err = -ENOTCONN;
1377         if (sk->sk_user_data == NULL)
1378                 goto end;
1379 
1380         /* Get session context from the socket */
1381         err = -EBADF;
1382         session = pppol2tp_sock_to_session(sk);
1383         if (session == NULL)
1384                 goto end;
1385 
1386         /* Special case: if session_id == 0x0000, treat as operation on tunnel
1387          */
1388         ps = l2tp_session_priv(session);
1389         if ((session->session_id == 0) &&
1390             (session->peer_session_id == 0)) {
1391                 err = -EBADF;
1392                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1393                 if (tunnel == NULL)
1394                         goto end_put_sess;
1395 
1396                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
1397                 sock_put(ps->tunnel_sock);
1398         } else
1399                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
1400 
1401         err = 0;
1402 
1403 end_put_sess:
1404         sock_put(sk);
1405 end:
1406         return err;
1407 }
1408 
1409 /* Tunnel getsockopt helper. Called with sock locked.
1410  */
1411 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
1412                                       struct l2tp_tunnel *tunnel,
1413                                       int optname, int *val)
1414 {
1415         int err = 0;
1416 
1417         switch (optname) {
1418         case PPPOL2TP_SO_DEBUG:
1419                 *val = tunnel->debug;
1420                 l2tp_info(tunnel, PPPOL2TP_MSG_CONTROL, "%s: get debug=%x\n",
1421                           tunnel->name, tunnel->debug);
1422                 break;
1423 
1424         default:
1425                 err = -ENOPROTOOPT;
1426                 break;
1427         }
1428 
1429         return err;
1430 }
1431 
1432 /* Session getsockopt helper. Called with sock locked.
1433  */
1434 static int pppol2tp_session_getsockopt(struct sock *sk,
1435                                        struct l2tp_session *session,
1436                                        int optname, int *val)
1437 {
1438         int err = 0;
1439 
1440         switch (optname) {
1441         case PPPOL2TP_SO_RECVSEQ:
1442                 *val = session->recv_seq;
1443                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1444                           "%s: get recv_seq=%d\n", session->name, *val);
1445                 break;
1446 
1447         case PPPOL2TP_SO_SENDSEQ:
1448                 *val = session->send_seq;
1449                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1450                           "%s: get send_seq=%d\n", session->name, *val);
1451                 break;
1452 
1453         case PPPOL2TP_SO_LNSMODE:
1454                 *val = session->lns_mode;
1455                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1456                           "%s: get lns_mode=%d\n", session->name, *val);
1457                 break;
1458 
1459         case PPPOL2TP_SO_DEBUG:
1460                 *val = session->debug;
1461                 l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: get debug=%d\n",
1462                           session->name, *val);
1463                 break;
1464 
1465         case PPPOL2TP_SO_REORDERTO:
1466                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
1467                 l2tp_info(session, PPPOL2TP_MSG_CONTROL,
1468                           "%s: get reorder_timeout=%d\n", session->name, *val);
1469                 break;
1470 
1471         default:
1472                 err = -ENOPROTOOPT;
1473         }
1474 
1475         return err;
1476 }
1477 
1478 /* Main getsockopt() entry point.
1479  * Does API checks, then calls either the tunnel or session getsockopt
1480  * handler, according to whether the PPPoX socket is a for a regular session
1481  * or the special tunnel type.
1482  */
1483 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
1484                                char __user *optval, int __user *optlen)
1485 {
1486         struct sock *sk = sock->sk;
1487         struct l2tp_session *session;
1488         struct l2tp_tunnel *tunnel;
1489         int val, len;
1490         int err;
1491         struct pppol2tp_session *ps;
1492 
1493         if (level != SOL_PPPOL2TP)
1494                 return -EINVAL;
1495 
1496         if (get_user(len, optlen))
1497                 return -EFAULT;
1498 
1499         len = min_t(unsigned int, len, sizeof(int));
1500 
1501         if (len < 0)
1502                 return -EINVAL;
1503 
1504         err = -ENOTCONN;
1505         if (sk->sk_user_data == NULL)
1506                 goto end;
1507 
1508         /* Get the session context */
1509         err = -EBADF;
1510         session = pppol2tp_sock_to_session(sk);
1511         if (session == NULL)
1512                 goto end;
1513 
1514         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
1515         ps = l2tp_session_priv(session);
1516         if ((session->session_id == 0) &&
1517             (session->peer_session_id == 0)) {
1518                 err = -EBADF;
1519                 tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
1520                 if (tunnel == NULL)
1521                         goto end_put_sess;
1522 
1523                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
1524                 sock_put(ps->tunnel_sock);
1525         } else
1526                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
1527 
1528         err = -EFAULT;
1529         if (put_user(len, optlen))
1530                 goto end_put_sess;
1531 
1532         if (copy_to_user((void __user *) optval, &val, len))
1533                 goto end_put_sess;
1534 
1535         err = 0;
1536 
1537 end_put_sess:
1538         sock_put(sk);
1539 end:
1540         return err;
1541 }
1542 
1543 /*****************************************************************************
1544  * /proc filesystem for debug
1545  * Since the original pppol2tp driver provided /proc/net/pppol2tp for
1546  * L2TPv2, we dump only L2TPv2 tunnels and sessions here.
1547  *****************************************************************************/
1548 
1549 static unsigned int pppol2tp_net_id;
1550 
1551 #ifdef CONFIG_PROC_FS
1552 
1553 struct pppol2tp_seq_data {
1554         struct seq_net_private p;
1555         int tunnel_idx;                 /* current tunnel */
1556         int session_idx;                /* index of session within current tunnel */
1557         struct l2tp_tunnel *tunnel;
1558         struct l2tp_session *session;   /* NULL means get next tunnel */
1559 };
1560 
1561 static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
1562 {
1563         for (;;) {
1564                 pd->tunnel = l2tp_tunnel_find_nth(net, pd->tunnel_idx);
1565                 pd->tunnel_idx++;
1566 
1567                 if (pd->tunnel == NULL)
1568                         break;
1569 
1570                 /* Ignore L2TPv3 tunnels */
1571                 if (pd->tunnel->version < 3)
1572                         break;
1573         }
1574 }
1575 
1576 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
1577 {
1578         pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
1579         pd->session_idx++;
1580 
1581         if (pd->session == NULL) {
1582                 pd->session_idx = 0;
1583                 pppol2tp_next_tunnel(net, pd);
1584         }
1585 }
1586 
1587 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
1588 {
1589         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
1590         loff_t pos = *offs;
1591         struct net *net;
1592 
1593         if (!pos)
1594                 goto out;
1595 
1596         BUG_ON(m->private == NULL);
1597         pd = m->private;
1598         net = seq_file_net(m);
1599 
1600         if (pd->tunnel == NULL)
1601                 pppol2tp_next_tunnel(net, pd);
1602         else
1603                 pppol2tp_next_session(net, pd);
1604 
1605         /* NULL tunnel and session indicates end of list */
1606         if ((pd->tunnel == NULL) && (pd->session == NULL))
1607                 pd = NULL;
1608 
1609 out:
1610         return pd;
1611 }
1612 
1613 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
1614 {
1615         (*pos)++;
1616         return NULL;
1617 }
1618 
1619 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
1620 {
1621         /* nothing to do */
1622 }
1623 
1624 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
1625 {
1626         struct l2tp_tunnel *tunnel = v;
1627 
1628         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
1629                    tunnel->name,
1630                    (tunnel == tunnel->sock->sk_user_data) ? 'Y' : 'N',
1631                    atomic_read(&tunnel->ref_count) - 1);
1632         seq_printf(m, " %08x %ld/%ld/%ld %ld/%ld/%ld\n",
1633                    tunnel->debug,
1634                    atomic_long_read(&tunnel->stats.tx_packets),
1635                    atomic_long_read(&tunnel->stats.tx_bytes),
1636                    atomic_long_read(&tunnel->stats.tx_errors),
1637                    atomic_long_read(&tunnel->stats.rx_packets),
1638                    atomic_long_read(&tunnel->stats.rx_bytes),
1639                    atomic_long_read(&tunnel->stats.rx_errors));
1640 }
1641 
1642 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
1643 {
1644         struct l2tp_session *session = v;
1645         struct l2tp_tunnel *tunnel = session->tunnel;
1646         struct pppol2tp_session *ps = l2tp_session_priv(session);
1647         struct pppox_sock *po = pppox_sk(ps->sock);
1648         u32 ip = 0;
1649         u16 port = 0;
1650 
1651         if (tunnel->sock) {
1652                 struct inet_sock *inet = inet_sk(tunnel->sock);
1653                 ip = ntohl(inet->inet_saddr);
1654                 port = ntohs(inet->inet_sport);
1655         }
1656 
1657         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
1658                    "%04X/%04X %d %c\n",
1659                    session->name, ip, port,
1660                    tunnel->tunnel_id,
1661                    session->session_id,
1662                    tunnel->peer_tunnel_id,
1663                    session->peer_session_id,
1664                    ps->sock->sk_state,
1665                    (session == ps->sock->sk_user_data) ?
1666                    'Y' : 'N');
1667         seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
1668                    session->mtu, session->mru,
1669                    session->recv_seq ? 'R' : '-',
1670                    session->send_seq ? 'S' : '-',
1671                    session->lns_mode ? "LNS" : "LAC",
1672                    session->debug,
1673                    jiffies_to_msecs(session->reorder_timeout));
1674         seq_printf(m, "   %hu/%hu %ld/%ld/%ld %ld/%ld/%ld\n",
1675                    session->nr, session->ns,
1676                    atomic_long_read(&session->stats.tx_packets),
1677                    atomic_long_read(&session->stats.tx_bytes),
1678                    atomic_long_read(&session->stats.tx_errors),
1679                    atomic_long_read(&session->stats.rx_packets),
1680                    atomic_long_read(&session->stats.rx_bytes),
1681                    atomic_long_read(&session->stats.rx_errors));
1682 
1683         if (po)
1684                 seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
1685 }
1686 
1687 static int pppol2tp_seq_show(struct seq_file *m, void *v)
1688 {
1689         struct pppol2tp_seq_data *pd = v;
1690 
1691         /* display header on line 1 */
1692         if (v == SEQ_START_TOKEN) {
1693                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
1694                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
1695                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1696                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
1697                          "dest-tid/sid state user-data-ok\n");
1698                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
1699                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
1700                 goto out;
1701         }
1702 
1703         /* Show the tunnel or session context.
1704          */
1705         if (pd->session == NULL)
1706                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
1707         else
1708                 pppol2tp_seq_session_show(m, pd->session);
1709 
1710 out:
1711         return 0;
1712 }
1713 
1714 static const struct seq_operations pppol2tp_seq_ops = {
1715         .start          = pppol2tp_seq_start,
1716         .next           = pppol2tp_seq_next,
1717         .stop           = pppol2tp_seq_stop,
1718         .show           = pppol2tp_seq_show,
1719 };
1720 
1721 /* Called when our /proc file is opened. We allocate data for use when
1722  * iterating our tunnel / session contexts and store it in the private
1723  * data of the seq_file.
1724  */
1725 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
1726 {
1727         return seq_open_net(inode, file, &pppol2tp_seq_ops,
1728                             sizeof(struct pppol2tp_seq_data));
1729 }
1730 
1731 static const struct file_operations pppol2tp_proc_fops = {
1732         .owner          = THIS_MODULE,
1733         .open           = pppol2tp_proc_open,
1734         .read           = seq_read,
1735         .llseek         = seq_lseek,
1736         .release        = seq_release_net,
1737 };
1738 
1739 #endif /* CONFIG_PROC_FS */
1740 
1741 /*****************************************************************************
1742  * Network namespace
1743  *****************************************************************************/
1744 
1745 static __net_init int pppol2tp_init_net(struct net *net)
1746 {
1747         struct proc_dir_entry *pde;
1748         int err = 0;
1749 
1750         pde = proc_create("pppol2tp", S_IRUGO, net->proc_net,
1751                           &pppol2tp_proc_fops);
1752         if (!pde) {
1753                 err = -ENOMEM;
1754                 goto out;
1755         }
1756 
1757 out:
1758         return err;
1759 }
1760 
1761 static __net_exit void pppol2tp_exit_net(struct net *net)
1762 {
1763         remove_proc_entry("pppol2tp", net->proc_net);
1764 }
1765 
1766 static struct pernet_operations pppol2tp_net_ops = {
1767         .init = pppol2tp_init_net,
1768         .exit = pppol2tp_exit_net,
1769         .id   = &pppol2tp_net_id,
1770 };
1771 
1772 /*****************************************************************************
1773  * Init and cleanup
1774  *****************************************************************************/
1775 
1776 static const struct proto_ops pppol2tp_ops = {
1777         .family         = AF_PPPOX,
1778         .owner          = THIS_MODULE,
1779         .release        = pppol2tp_release,
1780         .bind           = sock_no_bind,
1781         .connect        = pppol2tp_connect,
1782         .socketpair     = sock_no_socketpair,
1783         .accept         = sock_no_accept,
1784         .getname        = pppol2tp_getname,
1785         .poll           = datagram_poll,
1786         .listen         = sock_no_listen,
1787         .shutdown       = sock_no_shutdown,
1788         .setsockopt     = pppol2tp_setsockopt,
1789         .getsockopt     = pppol2tp_getsockopt,
1790         .sendmsg        = pppol2tp_sendmsg,
1791         .recvmsg        = pppol2tp_recvmsg,
1792         .mmap           = sock_no_mmap,
1793         .ioctl          = pppox_ioctl,
1794 };
1795 
1796 static const struct pppox_proto pppol2tp_proto = {
1797         .create         = pppol2tp_create,
1798         .ioctl          = pppol2tp_ioctl,
1799         .owner          = THIS_MODULE,
1800 };
1801 
1802 #ifdef CONFIG_L2TP_V3
1803 
1804 static const struct l2tp_nl_cmd_ops pppol2tp_nl_cmd_ops = {
1805         .session_create = pppol2tp_session_create,
1806         .session_delete = l2tp_session_delete,
1807 };
1808 
1809 #endif /* CONFIG_L2TP_V3 */
1810 
1811 static int __init pppol2tp_init(void)
1812 {
1813         int err;
1814 
1815         err = register_pernet_device(&pppol2tp_net_ops);
1816         if (err)
1817                 goto out;
1818 
1819         err = proto_register(&pppol2tp_sk_proto, 0);
1820         if (err)
1821                 goto out_unregister_pppol2tp_pernet;
1822 
1823         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
1824         if (err)
1825                 goto out_unregister_pppol2tp_proto;
1826 
1827 #ifdef CONFIG_L2TP_V3
1828         err = l2tp_nl_register_ops(L2TP_PWTYPE_PPP, &pppol2tp_nl_cmd_ops);
1829         if (err)
1830                 goto out_unregister_pppox;
1831 #endif
1832 
1833         pr_info("PPPoL2TP kernel driver, %s\n", PPPOL2TP_DRV_VERSION);
1834 
1835 out:
1836         return err;
1837 
1838 #ifdef CONFIG_L2TP_V3
1839 out_unregister_pppox:
1840         unregister_pppox_proto(PX_PROTO_OL2TP);
1841 #endif
1842 out_unregister_pppol2tp_proto:
1843         proto_unregister(&pppol2tp_sk_proto);
1844 out_unregister_pppol2tp_pernet:
1845         unregister_pernet_device(&pppol2tp_net_ops);
1846         goto out;
1847 }
1848 
1849 static void __exit pppol2tp_exit(void)
1850 {
1851 #ifdef CONFIG_L2TP_V3
1852         l2tp_nl_unregister_ops(L2TP_PWTYPE_PPP);
1853 #endif
1854         unregister_pppox_proto(PX_PROTO_OL2TP);
1855         proto_unregister(&pppol2tp_sk_proto);
1856         unregister_pernet_device(&pppol2tp_net_ops);
1857 }
1858 
1859 module_init(pppol2tp_init);
1860 module_exit(pppol2tp_exit);
1861 
1862 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1863 MODULE_DESCRIPTION("PPP over L2TP over UDP");
1864 MODULE_LICENSE("GPL");
1865 MODULE_VERSION(PPPOL2TP_DRV_VERSION);
1866 MODULE_ALIAS("pppox-proto-" __stringify(PX_PROTO_OL2TP));
1867 

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