forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathl2tp_ppp.c
1868 lines (1578 loc) · 47.5 KB
/
l2tp_ppp.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*****************************************************************************
* Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
*
* PPPoX --- Generic PPP encapsulation socket family
* PPPoL2TP --- PPP over L2TP (RFC 2661)
*
* Version: 2.0.0
*
* Authors: James Chapman ([email protected])
*
* Based on original work by Martijn van Oosterhout <[email protected]>
*
* License:
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
/* This driver handles only L2TP data frames; control frames are handled by a
* userspace application.
*
* To send data in an L2TP session, userspace opens a PPPoL2TP socket and
* attaches it to a bound UDP socket with local tunnel_id / session_id and
* peer tunnel_id / session_id set. Data can then be sent or received using
* regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
* can be read or modified using ioctl() or [gs]etsockopt() calls.
*
* When a PPPoL2TP socket is connected with local and peer session_id values
* zero, the socket is treated as a special tunnel management socket.
*
* Here's example userspace code to create a socket for sending/receiving data
* over an L2TP session:-
*
* struct sockaddr_pppol2tp sax;
* int fd;
* int session_fd;
*
* fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
*
* sax.sa_family = AF_PPPOX;
* sax.sa_protocol = PX_PROTO_OL2TP;
* sax.pppol2tp.fd = tunnel_fd; // bound UDP socket
* sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
* sax.pppol2tp.addr.sin_port = addr->sin_port;
* sax.pppol2tp.addr.sin_family = AF_INET;
* sax.pppol2tp.s_tunnel = tunnel_id;
* sax.pppol2tp.s_session = session_id;
* sax.pppol2tp.d_tunnel = peer_tunnel_id;
* sax.pppol2tp.d_session = peer_session_id;
*
* session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
*
* A pppd plugin that allows PPP traffic to be carried over L2TP using
* this driver is available from the OpenL2TP project at
* http://openl2tp.sourceforge.net.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/jiffies.h>
#include <linux/netdevice.h>
#include <linux/net.h>
#include <linux/inetdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/if_pppox.h>
#include <linux/if_pppol2tp.h>
#include <net/sock.h>
#include <linux/ppp_channel.h>
#include <linux/ppp_defs.h>
#include <linux/ppp-ioctl.h>
#include <linux/file.h>
#include <linux/hash.h>
#include <linux/sort.h>
#include <linux/proc_fs.h>
#include <linux/l2tp.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/xfrm.h>
#include <net/inet_common.h>
#include <asm/byteorder.h>
#include <linux/atomic.h>
#include "l2tp_core.h"
#define PPPOL2TP_DRV_VERSION "V2.0"
/* Space for UDP, L2TP and PPP headers */
#define PPPOL2TP_HEADER_OVERHEAD 40
/* Number of bytes to build transmit L2TP headers.
* Unfortunately the size is different depending on whether sequence numbers
* are enabled.
*/
#define PPPOL2TP_L2TP_HDR_SIZE_SEQ 10
#define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ 6
/* Private data of each session. This data lives at the end of struct
* l2tp_session, referenced via session->priv[].
*/
struct pppol2tp_session {
int owner; /* pid that opened the socket */
struct sock *sock; /* Pointer to the session
* PPPoX socket */
struct sock *tunnel_sock; /* Pointer to the tunnel UDP
* socket */
int flags; /* accessed by PPPIOCGFLAGS.
* Unused. */
};
static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
static const struct ppp_channel_ops pppol2tp_chan_ops = {
.start_xmit = pppol2tp_xmit,
};
static const struct proto_ops pppol2tp_ops;
/* Helpers to obtain tunnel/session contexts from sockets.
*/
static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
{
struct l2tp_session *session;
if (sk == NULL)
return NULL;
sock_hold(sk);
session = (struct l2tp_session *)(sk->sk_user_data);
if (session == NULL) {
sock_put(sk);
goto out;
}
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
out:
return session;
}
/*****************************************************************************
* Receive data handling
*****************************************************************************/
static int pppol2tp_recv_payload_hook(struct sk_buff *skb)
{
/* Skip PPP header, if present. In testing, Microsoft L2TP clients
* don't send the PPP header (PPP header compression enabled), but
* other clients can include the header. So we cope with both cases
* here. The PPP header is always FF03 when using L2TP.
*
* Note that skb->data[] isn't dereferenced from a u16 ptr here since
* the field may be unaligned.
*/
if (!pskb_may_pull(skb, 2))
return 1;
if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
skb_pull(skb, 2);
return 0;
}
/* Receive message. This is the recvmsg for the PPPoL2TP socket.
*/
static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t len,
int flags)
{
int err;
struct sk_buff *skb;
struct sock *sk = sock->sk;
err = -EIO;
if (sk->sk_state & PPPOX_BOUND)
goto end;
msg->msg_namelen = 0;
err = 0;
skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
flags & MSG_DONTWAIT, &err);
if (!skb)
goto end;
if (len > skb->len)
len = skb->len;
else if (len < skb->len)
msg->msg_flags |= MSG_TRUNC;
err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
if (likely(err == 0))
err = len;
kfree_skb(skb);
end:
return err;
}
static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
{
struct pppol2tp_session *ps = l2tp_session_priv(session);
struct sock *sk = NULL;
/* If the socket is bound, send it in to PPP's input queue. Otherwise
* queue it on the session socket.
*/
sk = ps->sock;
if (sk == NULL)
goto no_sock;
if (sk->sk_state & PPPOX_BOUND) {
struct pppox_sock *po;
l2tp_dbg(session, PPPOL2TP_MSG_DATA,
"%s: recv %d byte data frame, passing to ppp\n",
session->name, data_len);
/* We need to forget all info related to the L2TP packet
* gathered in the skb as we are going to reuse the same
* skb for the inner packet.
* Namely we need to:
* - reset xfrm (IPSec) information as it applies to
* the outer L2TP packet and not to the inner one
* - release the dst to force a route lookup on the inner
* IP packet since skb->dst currently points to the dst
* of the UDP tunnel
* - reset netfilter information as it doesn't apply
* to the inner packet either
*/
secpath_reset(skb);
skb_dst_drop(skb);
nf_reset(skb);
po = pppox_sk(sk);
ppp_input(&po->chan, skb);
} else {
l2tp_info(session, PPPOL2TP_MSG_DATA, "%s: socket not bound\n",
session->name);
/* Not bound. Nothing we can do, so discard. */
atomic_long_inc(&session->stats.rx_errors);
kfree_skb(skb);
}
return;
no_sock:
l2tp_info(session, PPPOL2TP_MSG_DATA, "%s: no socket\n", session->name);
kfree_skb(skb);
}
static void pppol2tp_session_sock_hold(struct l2tp_session *session)
{
struct pppol2tp_session *ps = l2tp_session_priv(session);
if (ps->sock)
sock_hold(ps->sock);
}
static void pppol2tp_session_sock_put(struct l2tp_session *session)
{
struct pppol2tp_session *ps = l2tp_session_priv(session);
if (ps->sock)
sock_put(ps->sock);
}
/************************************************************************
* Transmit handling
***********************************************************************/
/* This is the sendmsg for the PPPoL2TP pppol2tp_session socket. We come here
* when a user application does a sendmsg() on the session socket. L2TP and
* PPP headers must be inserted into the user's data.
*/
static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
size_t total_len)
{
static const unsigned char ppph[2] = { 0xff, 0x03 };
struct sock *sk = sock->sk;
struct sk_buff *skb;
int error;
struct l2tp_session *session;
struct l2tp_tunnel *tunnel;
struct pppol2tp_session *ps;
int uhlen;
error = -ENOTCONN;
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
goto error;
/* Get session and tunnel contexts */
error = -EBADF;
session = pppol2tp_sock_to_session(sk);
if (session == NULL)
goto error;
ps = l2tp_session_priv(session);
tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
if (tunnel == NULL)
goto error_put_sess;
uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
/* Allocate a socket buffer */
error = -ENOMEM;
skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
uhlen + session->hdr_len +
sizeof(ppph) + total_len,
0, GFP_KERNEL);
if (!skb)
goto error_put_sess_tun;
/* Reserve space for headers. */
skb_reserve(skb, NET_SKB_PAD);
skb_reset_network_header(skb);
skb_reserve(skb, sizeof(struct iphdr));
skb_reset_transport_header(skb);
skb_reserve(skb, uhlen);
/* Add PPP header */
skb->data[0] = ppph[0];
skb->data[1] = ppph[1];
skb_put(skb, 2);
/* Copy user data into skb */
error = memcpy_fromiovec(skb_put(skb, total_len), m->msg_iov,
total_len);
if (error < 0) {
kfree_skb(skb);
goto error_put_sess_tun;
}
local_bh_disable();
l2tp_xmit_skb(session, skb, session->hdr_len);
local_bh_enable();
sock_put(ps->tunnel_sock);
sock_put(sk);
return total_len;
error_put_sess_tun:
sock_put(ps->tunnel_sock);
error_put_sess:
sock_put(sk);
error:
return error;
}
/* Transmit function called by generic PPP driver. Sends PPP frame
* over PPPoL2TP socket.
*
* This is almost the same as pppol2tp_sendmsg(), but rather than
* being called with a msghdr from userspace, it is called with a skb
* from the kernel.
*
* The supplied skb from ppp doesn't have enough headroom for the
* insertion of L2TP, UDP and IP headers so we need to allocate more
* headroom in the skb. This will create a cloned skb. But we must be
* careful in the error case because the caller will expect to free
* the skb it supplied, not our cloned skb. So we take care to always
* leave the original skb unfreed if we return an error.
*/
static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
{
static const u8 ppph[2] = { 0xff, 0x03 };
struct sock *sk = (struct sock *) chan->private;
struct sock *sk_tun;
struct l2tp_session *session;
struct l2tp_tunnel *tunnel;
struct pppol2tp_session *ps;
int uhlen, headroom;
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
goto abort;
/* Get session and tunnel contexts from the socket */
session = pppol2tp_sock_to_session(sk);
if (session == NULL)
goto abort;
ps = l2tp_session_priv(session);
sk_tun = ps->tunnel_sock;
if (sk_tun == NULL)
goto abort_put_sess;
tunnel = l2tp_sock_to_tunnel(sk_tun);
if (tunnel == NULL)
goto abort_put_sess;
uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
headroom = NET_SKB_PAD +
sizeof(struct iphdr) + /* IP header */
uhlen + /* UDP header (if L2TP_ENCAPTYPE_UDP) */
session->hdr_len + /* L2TP header */
sizeof(ppph); /* PPP header */
if (skb_cow_head(skb, headroom))
goto abort_put_sess_tun;
/* Setup PPP header */
__skb_push(skb, sizeof(ppph));
skb->data[0] = ppph[0];
skb->data[1] = ppph[1];
local_bh_disable();
l2tp_xmit_skb(session, skb, session->hdr_len);
local_bh_enable();
sock_put(sk_tun);
sock_put(sk);
return 1;
abort_put_sess_tun:
sock_put(sk_tun);
abort_put_sess:
sock_put(sk);
abort:
/* Free the original skb */
kfree_skb(skb);
return 1;
}
/*****************************************************************************
* Session (and tunnel control) socket create/destroy.
*****************************************************************************/
/* Called by l2tp_core when a session socket is being closed.
*/
static void pppol2tp_session_close(struct l2tp_session *session)
{
struct pppol2tp_session *ps = l2tp_session_priv(session);
struct sock *sk = ps->sock;
struct socket *sock = sk->sk_socket;
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
if (sock) {
inet_shutdown(sock, 2);
/* Don't let the session go away before our socket does */
l2tp_session_inc_refcount(session);
}
return;
}
/* Really kill the session socket. (Called from sock_put() if
* refcnt == 0.)
*/
static void pppol2tp_session_destruct(struct sock *sk)
{
struct l2tp_session *session = sk->sk_user_data;
if (session) {
sk->sk_user_data = NULL;
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
l2tp_session_dec_refcount(session);
}
return;
}
/* Called when the PPPoX socket (session) is closed.
*/
static int pppol2tp_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct l2tp_session *session;
int error;
if (!sk)
return 0;
error = -EBADF;
lock_sock(sk);
if (sock_flag(sk, SOCK_DEAD) != 0)
goto error;
pppox_unbind_sock(sk);
/* Signal the death of the socket. */
sk->sk_state = PPPOX_DEAD;
sock_orphan(sk);
sock->sk = NULL;
session = pppol2tp_sock_to_session(sk);
/* Purge any queued data */
if (session != NULL) {
__l2tp_session_unhash(session);
l2tp_session_queue_purge(session);
sock_put(sk);
}
skb_queue_purge(&sk->sk_receive_queue);
skb_queue_purge(&sk->sk_write_queue);
release_sock(sk);
/* This will delete the session context via
* pppol2tp_session_destruct() if the socket's refcnt drops to
* zero.
*/
sock_put(sk);
return 0;
error:
release_sock(sk);
return error;
}
static struct proto pppol2tp_sk_proto = {
.name = "PPPOL2TP",
.owner = THIS_MODULE,
.obj_size = sizeof(struct pppox_sock),
};
static int pppol2tp_backlog_recv(struct sock *sk, struct sk_buff *skb)
{
int rc;
rc = l2tp_udp_encap_recv(sk, skb);
if (rc)
kfree_skb(skb);
return NET_RX_SUCCESS;
}
/* socket() handler. Initialize a new struct sock.
*/
static int pppol2tp_create(struct net *net, struct socket *sock)
{
int error = -ENOMEM;
struct sock *sk;
sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
if (!sk)
goto out;
sock_init_data(sock, sk);
sock->state = SS_UNCONNECTED;
sock->ops = &pppol2tp_ops;
sk->sk_backlog_rcv = pppol2tp_backlog_recv;
sk->sk_protocol = PX_PROTO_OL2TP;
sk->sk_family = PF_PPPOX;
sk->sk_state = PPPOX_NONE;
sk->sk_type = SOCK_STREAM;
sk->sk_destruct = pppol2tp_session_destruct;
error = 0;
out:
return error;
}
#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
static void pppol2tp_show(struct seq_file *m, void *arg)
{
struct l2tp_session *session = arg;
struct pppol2tp_session *ps = l2tp_session_priv(session);
if (ps) {
struct pppox_sock *po = pppox_sk(ps->sock);
if (po)
seq_printf(m, " interface %s\n", ppp_dev_name(&po->chan));
}
}
#endif
/* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
*/
static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
int sockaddr_len, int flags)
{
struct sock *sk = sock->sk;
struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
struct pppox_sock *po = pppox_sk(sk);
struct l2tp_session *session = NULL;
struct l2tp_tunnel *tunnel;
struct pppol2tp_session *ps;
struct dst_entry *dst;
struct l2tp_session_cfg cfg = { 0, };
int error = 0;
u32 tunnel_id, peer_tunnel_id;
u32 session_id, peer_session_id;
int ver = 2;
int fd;
lock_sock(sk);
error = -EINVAL;
if (sp->sa_protocol != PX_PROTO_OL2TP)
goto end;
/* Check for already bound sockets */
error = -EBUSY;
if (sk->sk_state & PPPOX_CONNECTED)
goto end;
/* We don't supporting rebinding anyway */
error = -EALREADY;
if (sk->sk_user_data)
goto end; /* socket is already attached */
/* Get params from socket address. Handle L2TPv2 and L2TPv3.
* This is nasty because there are different sockaddr_pppol2tp
* structs for L2TPv2, L2TPv3, over IPv4 and IPv6. We use
* the sockaddr size to determine which structure the caller
* is using.
*/
peer_tunnel_id = 0;
if (sockaddr_len == sizeof(struct sockaddr_pppol2tp)) {
fd = sp->pppol2tp.fd;
tunnel_id = sp->pppol2tp.s_tunnel;
peer_tunnel_id = sp->pppol2tp.d_tunnel;
session_id = sp->pppol2tp.s_session;
peer_session_id = sp->pppol2tp.d_session;
} else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3)) {
struct sockaddr_pppol2tpv3 *sp3 =
(struct sockaddr_pppol2tpv3 *) sp;
ver = 3;
fd = sp3->pppol2tp.fd;
tunnel_id = sp3->pppol2tp.s_tunnel;
peer_tunnel_id = sp3->pppol2tp.d_tunnel;
session_id = sp3->pppol2tp.s_session;
peer_session_id = sp3->pppol2tp.d_session;
} else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpin6)) {
struct sockaddr_pppol2tpin6 *sp6 =
(struct sockaddr_pppol2tpin6 *) sp;
fd = sp6->pppol2tp.fd;
tunnel_id = sp6->pppol2tp.s_tunnel;
peer_tunnel_id = sp6->pppol2tp.d_tunnel;
session_id = sp6->pppol2tp.s_session;
peer_session_id = sp6->pppol2tp.d_session;
} else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3in6)) {
struct sockaddr_pppol2tpv3in6 *sp6 =
(struct sockaddr_pppol2tpv3in6 *) sp;
ver = 3;
fd = sp6->pppol2tp.fd;
tunnel_id = sp6->pppol2tp.s_tunnel;
peer_tunnel_id = sp6->pppol2tp.d_tunnel;
session_id = sp6->pppol2tp.s_session;
peer_session_id = sp6->pppol2tp.d_session;
} else {
error = -EINVAL;
goto end; /* bad socket address */
}
/* Don't bind if tunnel_id is 0 */
error = -EINVAL;
if (tunnel_id == 0)
goto end;
tunnel = l2tp_tunnel_find(sock_net(sk), tunnel_id);
/* Special case: create tunnel context if session_id and
* peer_session_id is 0. Otherwise look up tunnel using supplied
* tunnel id.
*/
if ((session_id == 0) && (peer_session_id == 0)) {
if (tunnel == NULL) {
struct l2tp_tunnel_cfg tcfg = {
.encap = L2TP_ENCAPTYPE_UDP,
.debug = 0,
};
error = l2tp_tunnel_create(sock_net(sk), fd, ver, tunnel_id, peer_tunnel_id, &tcfg, &tunnel);
if (error < 0)
goto end;
}
} else {
/* Error if we can't find the tunnel */
error = -ENOENT;
if (tunnel == NULL)
goto end;
/* Error if socket is not prepped */
if (tunnel->sock == NULL)
goto end;
}
if (tunnel->recv_payload_hook == NULL)
tunnel->recv_payload_hook = pppol2tp_recv_payload_hook;
if (tunnel->peer_tunnel_id == 0)
tunnel->peer_tunnel_id = peer_tunnel_id;
/* Create session if it doesn't already exist. We handle the
* case where a session was previously created by the netlink
* interface by checking that the session doesn't already have
* a socket and its tunnel socket are what we expect. If any
* of those checks fail, return EEXIST to the caller.
*/
session = l2tp_session_find(sock_net(sk), tunnel, session_id);
if (session == NULL) {
/* Default MTU must allow space for UDP/L2TP/PPP
* headers.
*/
cfg.mtu = cfg.mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
/* Allocate and initialize a new session context. */
session = l2tp_session_create(sizeof(struct pppol2tp_session),
tunnel, session_id,
peer_session_id, &cfg);
if (session == NULL) {
error = -ENOMEM;
goto end;
}
} else {
ps = l2tp_session_priv(session);
error = -EEXIST;
if (ps->sock != NULL)
goto end;
/* consistency checks */
if (ps->tunnel_sock != tunnel->sock)
goto end;
}
/* Associate session with its PPPoL2TP socket */
ps = l2tp_session_priv(session);
ps->owner = current->pid;
ps->sock = sk;
ps->tunnel_sock = tunnel->sock;
session->recv_skb = pppol2tp_recv;
session->session_close = pppol2tp_session_close;
#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
session->show = pppol2tp_show;
#endif
/* We need to know each time a skb is dropped from the reorder
* queue.
*/
session->ref = pppol2tp_session_sock_hold;
session->deref = pppol2tp_session_sock_put;
/* If PMTU discovery was enabled, use the MTU that was discovered */
dst = sk_dst_get(sk);
if (dst != NULL) {
u32 pmtu = dst_mtu(__sk_dst_get(sk));
if (pmtu != 0)
session->mtu = session->mru = pmtu -
PPPOL2TP_HEADER_OVERHEAD;
dst_release(dst);
}
/* Special case: if source & dest session_id == 0x0000, this
* socket is being created to manage the tunnel. Just set up
* the internal context for use by ioctl() and sockopt()
* handlers.
*/
if ((session->session_id == 0) &&
(session->peer_session_id == 0)) {
error = 0;
goto out_no_ppp;
}
/* The only header we need to worry about is the L2TP
* header. This size is different depending on whether
* sequence numbers are enabled for the data channel.
*/
po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
po->chan.private = sk;
po->chan.ops = &pppol2tp_chan_ops;
po->chan.mtu = session->mtu;
error = ppp_register_net_channel(sock_net(sk), &po->chan);
if (error)
goto end;
out_no_ppp:
/* This is how we get the session context from the socket. */
sk->sk_user_data = session;
sk->sk_state = PPPOX_CONNECTED;
l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: created\n",
session->name);
end:
release_sock(sk);
return error;
}
#ifdef CONFIG_L2TP_V3
/* Called when creating sessions via the netlink interface.
*/
static int pppol2tp_session_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
{
int error;
struct l2tp_tunnel *tunnel;
struct l2tp_session *session;
struct pppol2tp_session *ps;
tunnel = l2tp_tunnel_find(net, tunnel_id);
/* Error if we can't find the tunnel */
error = -ENOENT;
if (tunnel == NULL)
goto out;
/* Error if tunnel socket is not prepped */
if (tunnel->sock == NULL)
goto out;
/* Check that this session doesn't already exist */
error = -EEXIST;
session = l2tp_session_find(net, tunnel, session_id);
if (session != NULL)
goto out;
/* Default MTU values. */
if (cfg->mtu == 0)
cfg->mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
if (cfg->mru == 0)
cfg->mru = cfg->mtu;
/* Allocate and initialize a new session context. */
error = -ENOMEM;
session = l2tp_session_create(sizeof(struct pppol2tp_session),
tunnel, session_id,
peer_session_id, cfg);
if (session == NULL)
goto out;
ps = l2tp_session_priv(session);
ps->tunnel_sock = tunnel->sock;
l2tp_info(session, PPPOL2TP_MSG_CONTROL, "%s: created\n",
session->name);
error = 0;
out:
return error;
}
#endif /* CONFIG_L2TP_V3 */
/* getname() support.
*/
static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
int *usockaddr_len, int peer)
{
int len = 0;
int error = 0;
struct l2tp_session *session;
struct l2tp_tunnel *tunnel;
struct sock *sk = sock->sk;
struct inet_sock *inet;
struct pppol2tp_session *pls;
error = -ENOTCONN;
if (sk == NULL)
goto end;
if (sk->sk_state != PPPOX_CONNECTED)
goto end;
error = -EBADF;
session = pppol2tp_sock_to_session(sk);
if (session == NULL)
goto end;
pls = l2tp_session_priv(session);
tunnel = l2tp_sock_to_tunnel(pls->tunnel_sock);
if (tunnel == NULL) {
error = -EBADF;
goto end_put_sess;
}
inet = inet_sk(tunnel->sock);
if ((tunnel->version == 2) && (tunnel->sock->sk_family == AF_INET)) {
struct sockaddr_pppol2tp sp;
len = sizeof(sp);
memset(&sp, 0, len);
sp.sa_family = AF_PPPOX;
sp.sa_protocol = PX_PROTO_OL2TP;
sp.pppol2tp.fd = tunnel->fd;
sp.pppol2tp.pid = pls->owner;
sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
sp.pppol2tp.s_session = session->session_id;
sp.pppol2tp.d_session = session->peer_session_id;
sp.pppol2tp.addr.sin_family = AF_INET;
sp.pppol2tp.addr.sin_port = inet->inet_dport;
sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
memcpy(uaddr, &sp, len);
#if IS_ENABLED(CONFIG_IPV6)
} else if ((tunnel->version == 2) &&
(tunnel->sock->sk_family == AF_INET6)) {
struct sockaddr_pppol2tpin6 sp;
len = sizeof(sp);
memset(&sp, 0, len);
sp.sa_family = AF_PPPOX;
sp.sa_protocol = PX_PROTO_OL2TP;
sp.pppol2tp.fd = tunnel->fd;
sp.pppol2tp.pid = pls->owner;
sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
sp.pppol2tp.s_session = session->session_id;
sp.pppol2tp.d_session = session->peer_session_id;
sp.pppol2tp.addr.sin6_family = AF_INET6;
sp.pppol2tp.addr.sin6_port = inet->inet_dport;
memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
sizeof(tunnel->sock->sk_v6_daddr));
memcpy(uaddr, &sp, len);
} else if ((tunnel->version == 3) &&
(tunnel->sock->sk_family == AF_INET6)) {
struct sockaddr_pppol2tpv3in6 sp;
len = sizeof(sp);
memset(&sp, 0, len);
sp.sa_family = AF_PPPOX;
sp.sa_protocol = PX_PROTO_OL2TP;
sp.pppol2tp.fd = tunnel->fd;
sp.pppol2tp.pid = pls->owner;
sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
sp.pppol2tp.s_session = session->session_id;
sp.pppol2tp.d_session = session->peer_session_id;
sp.pppol2tp.addr.sin6_family = AF_INET6;
sp.pppol2tp.addr.sin6_port = inet->inet_dport;
memcpy(&sp.pppol2tp.addr.sin6_addr, &tunnel->sock->sk_v6_daddr,
sizeof(tunnel->sock->sk_v6_daddr));
memcpy(uaddr, &sp, len);
#endif
} else if (tunnel->version == 3) {
struct sockaddr_pppol2tpv3 sp;
len = sizeof(sp);
memset(&sp, 0, len);
sp.sa_family = AF_PPPOX;
sp.sa_protocol = PX_PROTO_OL2TP;
sp.pppol2tp.fd = tunnel->fd;
sp.pppol2tp.pid = pls->owner;
sp.pppol2tp.s_tunnel = tunnel->tunnel_id;
sp.pppol2tp.d_tunnel = tunnel->peer_tunnel_id;
sp.pppol2tp.s_session = session->session_id;
sp.pppol2tp.d_session = session->peer_session_id;
sp.pppol2tp.addr.sin_family = AF_INET;
sp.pppol2tp.addr.sin_port = inet->inet_dport;
sp.pppol2tp.addr.sin_addr.s_addr = inet->inet_daddr;
memcpy(uaddr, &sp, len);
}
*usockaddr_len = len;
sock_put(pls->tunnel_sock);
end_put_sess:
sock_put(sk);
error = 0;
end:
return error;
}
/****************************************************************************
* ioctl() handlers.
*
* The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
* sockets. However, in order to control kernel tunnel features, we allow
* userspace to create a special "tunnel" PPPoX socket which is used for
* control only. Tunnel PPPoX sockets have session_id == 0 and simply allow
* the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
* calls.
****************************************************************************/
static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
struct l2tp_stats *stats)
{
dest->tx_packets = atomic_long_read(&stats->tx_packets);
dest->tx_bytes = atomic_long_read(&stats->tx_bytes);
dest->tx_errors = atomic_long_read(&stats->tx_errors);
dest->rx_packets = atomic_long_read(&stats->rx_packets);
dest->rx_bytes = atomic_long_read(&stats->rx_bytes);
dest->rx_seq_discards = atomic_long_read(&stats->rx_seq_discards);
dest->rx_oos_packets = atomic_long_read(&stats->rx_oos_packets);
dest->rx_errors = atomic_long_read(&stats->rx_errors);