1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Point-to-Point Tunneling Protocol for Linux
4 *
5 * Authors: Dmitry Kozlov <xeb@mail.ru>
6 */
7
8 #include <linux/string.h>
9 #include <linux/module.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/errno.h>
13 #include <linux/netdevice.h>
14 #include <linux/net.h>
15 #include <linux/skbuff.h>
16 #include <linux/vmalloc.h>
17 #include <linux/init.h>
18 #include <linux/ppp_channel.h>
19 #include <linux/ppp_defs.h>
20 #include <linux/if_pppox.h>
21 #include <linux/ppp-ioctl.h>
22 #include <linux/notifier.h>
23 #include <linux/file.h>
24 #include <linux/in.h>
25 #include <linux/ip.h>
26 #include <linux/rcupdate.h>
27 #include <linux/security.h>
28 #include <linux/spinlock.h>
29
30 #include <net/sock.h>
31 #include <net/protocol.h>
32 #include <net/ip.h>
33 #include <net/icmp.h>
34 #include <net/route.h>
35 #include <net/gre.h>
36 #include <net/pptp.h>
37
38 #include <linux/uaccess.h>
39
40 #define PPTP_DRIVER_VERSION "0.8.5"
41
42 #define MAX_CALLID 65535
43
44 static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1);
45 static struct pppox_sock __rcu **callid_sock;
46
47 static DEFINE_SPINLOCK(chan_lock);
48
49 static struct proto pptp_sk_proto __read_mostly;
50 static const struct ppp_channel_ops pptp_chan_ops;
51 static const struct proto_ops pptp_ops;
52
lookup_chan(u16 call_id, __be32 s_addr)53 static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr)
54 {
55 struct pppox_sock *sock;
56 struct pptp_opt *opt;
57
58 rcu_read_lock();
59 sock = rcu_dereference(callid_sock[call_id]);
60 if (sock) {
61 opt = &sock->proto.pptp;
62 if (opt->dst_addr.sin_addr.s_addr != s_addr)
63 sock = NULL;
64 else
65 sock_hold(sk_pppox(sock));
66 }
67 rcu_read_unlock();
68
69 return sock;
70 }
71
lookup_chan_dst(u16 call_id, __be32 d_addr)72 static int lookup_chan_dst(u16 call_id, __be32 d_addr)
73 {
74 struct pppox_sock *sock;
75 struct pptp_opt *opt;
76 int i;
77
78 rcu_read_lock();
79 i = 1;
80 for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) {
81 sock = rcu_dereference(callid_sock[i]);
82 if (!sock)
83 continue;
84 opt = &sock->proto.pptp;
85 if (opt->dst_addr.call_id == call_id &&
86 opt->dst_addr.sin_addr.s_addr == d_addr)
87 break;
88 }
89 rcu_read_unlock();
90
91 return i < MAX_CALLID;
92 }
93
add_chan(struct pppox_sock *sock, struct pptp_addr *sa)94 static int add_chan(struct pppox_sock *sock,
95 struct pptp_addr *sa)
96 {
97 static int call_id;
98
99 spin_lock(&chan_lock);
100 if (!sa->call_id) {
101 call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, call_id + 1);
102 if (call_id == MAX_CALLID) {
103 call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, 1);
104 if (call_id == MAX_CALLID)
105 goto out_err;
106 }
107 sa->call_id = call_id;
108 } else if (test_bit(sa->call_id, callid_bitmap)) {
109 goto out_err;
110 }
111
112 sock->proto.pptp.src_addr = *sa;
113 set_bit(sa->call_id, callid_bitmap);
114 rcu_assign_pointer(callid_sock[sa->call_id], sock);
115 spin_unlock(&chan_lock);
116
117 return 0;
118
119 out_err:
120 spin_unlock(&chan_lock);
121 return -1;
122 }
123
del_chan(struct pppox_sock *sock)124 static void del_chan(struct pppox_sock *sock)
125 {
126 spin_lock(&chan_lock);
127 clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
128 RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL);
129 spin_unlock(&chan_lock);
130 }
131
pptp_route_output(struct pppox_sock *po, struct flowi4 *fl4)132 static struct rtable *pptp_route_output(struct pppox_sock *po,
133 struct flowi4 *fl4)
134 {
135 struct sock *sk = &po->sk;
136 struct net *net;
137
138 net = sock_net(sk);
139 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 0,
140 RT_SCOPE_UNIVERSE, IPPROTO_GRE, 0,
141 po->proto.pptp.dst_addr.sin_addr.s_addr,
142 po->proto.pptp.src_addr.sin_addr.s_addr,
143 0, 0, sock_net_uid(net, sk));
144 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
145
146 return ip_route_output_flow(net, fl4, sk);
147 }
148
pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb)149 static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
150 {
151 struct sock *sk = (struct sock *) chan->private;
152 struct pppox_sock *po = pppox_sk(sk);
153 struct net *net = sock_net(sk);
154 struct pptp_opt *opt = &po->proto.pptp;
155 struct pptp_gre_header *hdr;
156 unsigned int header_len = sizeof(*hdr);
157 struct flowi4 fl4;
158 int islcp;
159 int len;
160 unsigned char *data;
161 __u32 seq_recv;
162
163
164 struct rtable *rt;
165 struct net_device *tdev;
166 struct iphdr *iph;
167 int max_headroom;
168
169 if (sk_pppox(po)->sk_state & PPPOX_DEAD)
170 goto tx_error;
171
172 rt = pptp_route_output(po, &fl4);
173 if (IS_ERR(rt))
174 goto tx_error;
175
176 tdev = rt->dst.dev;
177
178 max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(*iph) + sizeof(*hdr) + 2;
179
180 if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
181 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
182 if (!new_skb) {
183 ip_rt_put(rt);
184 goto tx_error;
185 }
186 if (skb->sk)
187 skb_set_owner_w(new_skb, skb->sk);
188 consume_skb(skb);
189 skb = new_skb;
190 }
191
192 data = skb->data;
193 islcp = ((data[0] << 8) + data[1]) == PPP_LCP && 1 <= data[2] && data[2] <= 7;
194
195 /* compress protocol field */
196 if ((opt->ppp_flags & SC_COMP_PROT) && data[0] == 0 && !islcp)
197 skb_pull(skb, 1);
198
199 /* Put in the address/control bytes if necessary */
200 if ((opt->ppp_flags & SC_COMP_AC) == 0 || islcp) {
201 data = skb_push(skb, 2);
202 data[0] = PPP_ALLSTATIONS;
203 data[1] = PPP_UI;
204 }
205
206 len = skb->len;
207
208 seq_recv = opt->seq_recv;
209
210 if (opt->ack_sent == seq_recv)
211 header_len -= sizeof(hdr->ack);
212
213 /* Push down and install GRE header */
214 skb_push(skb, header_len);
215 hdr = (struct pptp_gre_header *)(skb->data);
216
217 hdr->gre_hd.flags = GRE_KEY | GRE_VERSION_1 | GRE_SEQ;
218 hdr->gre_hd.protocol = GRE_PROTO_PPP;
219 hdr->call_id = htons(opt->dst_addr.call_id);
220
221 hdr->seq = htonl(++opt->seq_sent);
222 if (opt->ack_sent != seq_recv) {
223 /* send ack with this message */
224 hdr->gre_hd.flags |= GRE_ACK;
225 hdr->ack = htonl(seq_recv);
226 opt->ack_sent = seq_recv;
227 }
228 hdr->payload_len = htons(len);
229
230 /* Push down and install the IP header. */
231
232 skb_reset_transport_header(skb);
233 skb_push(skb, sizeof(*iph));
234 skb_reset_network_header(skb);
235 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
236 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED);
237
238 iph = ip_hdr(skb);
239 iph->version = 4;
240 iph->ihl = sizeof(struct iphdr) >> 2;
241 if (ip_dont_fragment(sk, &rt->dst))
242 iph->frag_off = htons(IP_DF);
243 else
244 iph->frag_off = 0;
245 iph->protocol = IPPROTO_GRE;
246 iph->tos = 0;
247 iph->daddr = fl4.daddr;
248 iph->saddr = fl4.saddr;
249 iph->ttl = ip4_dst_hoplimit(&rt->dst);
250 iph->tot_len = htons(skb->len);
251
252 skb_dst_drop(skb);
253 skb_dst_set(skb, &rt->dst);
254
255 nf_reset_ct(skb);
256
257 skb->ip_summed = CHECKSUM_NONE;
258 ip_select_ident(net, skb, NULL);
259 ip_send_check(iph);
260
261 ip_local_out(net, skb->sk, skb);
262 return 1;
263
264 tx_error:
265 kfree_skb(skb);
266 return 1;
267 }
268
pptp_rcv_core(struct sock *sk, struct sk_buff *skb)269 static int pptp_rcv_core(struct sock *sk, struct sk_buff *skb)
270 {
271 struct pppox_sock *po = pppox_sk(sk);
272 struct pptp_opt *opt = &po->proto.pptp;
273 int headersize, payload_len, seq;
274 __u8 *payload;
275 struct pptp_gre_header *header;
276
277 if (!(sk->sk_state & PPPOX_CONNECTED)) {
278 if (sock_queue_rcv_skb(sk, skb))
279 goto drop;
280 return NET_RX_SUCCESS;
281 }
282
283 header = (struct pptp_gre_header *)(skb->data);
284 headersize = sizeof(*header);
285
286 /* test if acknowledgement present */
287 if (GRE_IS_ACK(header->gre_hd.flags)) {
288 __u32 ack;
289
290 if (!pskb_may_pull(skb, headersize))
291 goto drop;
292 header = (struct pptp_gre_header *)(skb->data);
293
294 /* ack in different place if S = 0 */
295 ack = GRE_IS_SEQ(header->gre_hd.flags) ? header->ack : header->seq;
296
297 ack = ntohl(ack);
298
299 if (ack > opt->ack_recv)
300 opt->ack_recv = ack;
301 /* also handle sequence number wrap-around */
302 if (WRAPPED(ack, opt->ack_recv))
303 opt->ack_recv = ack;
304 } else {
305 headersize -= sizeof(header->ack);
306 }
307 /* test if payload present */
308 if (!GRE_IS_SEQ(header->gre_hd.flags))
309 goto drop;
310
311 payload_len = ntohs(header->payload_len);
312 seq = ntohl(header->seq);
313
314 /* check for incomplete packet (length smaller than expected) */
315 if (!pskb_may_pull(skb, headersize + payload_len))
316 goto drop;
317
318 payload = skb->data + headersize;
319 /* check for expected sequence number */
320 if (seq < opt->seq_recv + 1 || WRAPPED(opt->seq_recv, seq)) {
321 if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) &&
322 (PPP_PROTOCOL(payload) == PPP_LCP) &&
323 ((payload[4] == PPP_LCP_ECHOREQ) || (payload[4] == PPP_LCP_ECHOREP)))
324 goto allow_packet;
325 } else {
326 opt->seq_recv = seq;
327 allow_packet:
328 skb_pull(skb, headersize);
329
330 if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) {
331 /* chop off address/control */
332 if (skb->len < 3)
333 goto drop;
334 skb_pull(skb, 2);
335 }
336
337 skb->ip_summed = CHECKSUM_NONE;
338 skb_set_network_header(skb, skb->head-skb->data);
339 ppp_input(&po->chan, skb);
340
341 return NET_RX_SUCCESS;
342 }
343 drop:
344 kfree_skb(skb);
345 return NET_RX_DROP;
346 }
347
pptp_rcv(struct sk_buff *skb)348 static int pptp_rcv(struct sk_buff *skb)
349 {
350 struct pppox_sock *po;
351 struct pptp_gre_header *header;
352 struct iphdr *iph;
353
354 if (skb->pkt_type != PACKET_HOST)
355 goto drop;
356
357 if (!pskb_may_pull(skb, 12))
358 goto drop;
359
360 iph = ip_hdr(skb);
361
362 header = (struct pptp_gre_header *)skb->data;
363
364 if (header->gre_hd.protocol != GRE_PROTO_PPP || /* PPTP-GRE protocol for PPTP */
365 GRE_IS_CSUM(header->gre_hd.flags) || /* flag CSUM should be clear */
366 GRE_IS_ROUTING(header->gre_hd.flags) || /* flag ROUTING should be clear */
367 !GRE_IS_KEY(header->gre_hd.flags) || /* flag KEY should be set */
368 (header->gre_hd.flags & GRE_FLAGS)) /* flag Recursion Ctrl should be clear */
369 /* if invalid, discard this packet */
370 goto drop;
371
372 po = lookup_chan(htons(header->call_id), iph->saddr);
373 if (po) {
374 skb_dst_drop(skb);
375 nf_reset_ct(skb);
376 return sk_receive_skb(sk_pppox(po), skb, 0);
377 }
378 drop:
379 kfree_skb(skb);
380 return NET_RX_DROP;
381 }
382
pptp_bind(struct socket *sock, struct sockaddr *uservaddr, int sockaddr_len)383 static int pptp_bind(struct socket *sock, struct sockaddr *uservaddr,
384 int sockaddr_len)
385 {
386 struct sock *sk = sock->sk;
387 struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
388 struct pppox_sock *po = pppox_sk(sk);
389 int error = 0;
390
391 if (sockaddr_len < sizeof(struct sockaddr_pppox))
392 return -EINVAL;
393
394 lock_sock(sk);
395
396 if (sk->sk_state & PPPOX_DEAD) {
397 error = -EALREADY;
398 goto out;
399 }
400
401 if (sk->sk_state & PPPOX_BOUND) {
402 error = -EBUSY;
403 goto out;
404 }
405
406 if (add_chan(po, &sp->sa_addr.pptp))
407 error = -EBUSY;
408 else
409 sk->sk_state |= PPPOX_BOUND;
410
411 out:
412 release_sock(sk);
413 return error;
414 }
415
pptp_connect(struct socket *sock, struct sockaddr *uservaddr, int sockaddr_len, int flags)416 static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr,
417 int sockaddr_len, int flags)
418 {
419 struct sock *sk = sock->sk;
420 struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
421 struct pppox_sock *po = pppox_sk(sk);
422 struct pptp_opt *opt = &po->proto.pptp;
423 struct rtable *rt;
424 struct flowi4 fl4;
425 int error = 0;
426
427 if (sockaddr_len < sizeof(struct sockaddr_pppox))
428 return -EINVAL;
429
430 if (sp->sa_protocol != PX_PROTO_PPTP)
431 return -EINVAL;
432
433 if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr))
434 return -EALREADY;
435
436 lock_sock(sk);
437 /* Check for already bound sockets */
438 if (sk->sk_state & PPPOX_CONNECTED) {
439 error = -EBUSY;
440 goto end;
441 }
442
443 /* Check for already disconnected sockets, on attempts to disconnect */
444 if (sk->sk_state & PPPOX_DEAD) {
445 error = -EALREADY;
446 goto end;
447 }
448
449 if (!opt->src_addr.sin_addr.s_addr || !sp->sa_addr.pptp.sin_addr.s_addr) {
450 error = -EINVAL;
451 goto end;
452 }
453
454 po->chan.private = sk;
455 po->chan.ops = &pptp_chan_ops;
456
457 rt = pptp_route_output(po, &fl4);
458 if (IS_ERR(rt)) {
459 error = -EHOSTUNREACH;
460 goto end;
461 }
462 sk_setup_caps(sk, &rt->dst);
463
464 po->chan.mtu = dst_mtu(&rt->dst);
465 if (!po->chan.mtu)
466 po->chan.mtu = PPP_MRU;
467 po->chan.mtu -= PPTP_HEADER_OVERHEAD;
468
469 po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header);
470 error = ppp_register_channel(&po->chan);
471 if (error) {
472 pr_err("PPTP: failed to register PPP channel (%d)\n", error);
473 goto end;
474 }
475
476 opt->dst_addr = sp->sa_addr.pptp;
477 sk->sk_state |= PPPOX_CONNECTED;
478
479 end:
480 release_sock(sk);
481 return error;
482 }
483
pptp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)484 static int pptp_getname(struct socket *sock, struct sockaddr *uaddr,
485 int peer)
486 {
487 int len = sizeof(struct sockaddr_pppox);
488 struct sockaddr_pppox sp;
489
490 memset(&sp.sa_addr, 0, sizeof(sp.sa_addr));
491
492 sp.sa_family = AF_PPPOX;
493 sp.sa_protocol = PX_PROTO_PPTP;
494 sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr;
495
496 memcpy(uaddr, &sp, len);
497
498 return len;
499 }
500
pptp_release(struct socket *sock)501 static int pptp_release(struct socket *sock)
502 {
503 struct sock *sk = sock->sk;
504 struct pppox_sock *po;
505 int error = 0;
506
507 if (!sk)
508 return 0;
509
510 lock_sock(sk);
511
512 if (sock_flag(sk, SOCK_DEAD)) {
513 release_sock(sk);
514 return -EBADF;
515 }
516
517 po = pppox_sk(sk);
518 del_chan(po);
519 synchronize_rcu();
520
521 pppox_unbind_sock(sk);
522 sk->sk_state = PPPOX_DEAD;
523
524 sock_orphan(sk);
525 sock->sk = NULL;
526
527 release_sock(sk);
528 sock_put(sk);
529
530 return error;
531 }
532
pptp_sock_destruct(struct sock *sk)533 static void pptp_sock_destruct(struct sock *sk)
534 {
535 if (!(sk->sk_state & PPPOX_DEAD)) {
536 del_chan(pppox_sk(sk));
537 pppox_unbind_sock(sk);
538 }
539 skb_queue_purge(&sk->sk_receive_queue);
540 dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));
541 }
542
pptp_create(struct net *net, struct socket *sock, int kern)543 static int pptp_create(struct net *net, struct socket *sock, int kern)
544 {
545 int error = -ENOMEM;
546 struct sock *sk;
547 struct pppox_sock *po;
548 struct pptp_opt *opt;
549
550 sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, kern);
551 if (!sk)
552 goto out;
553
554 sock_init_data(sock, sk);
555
556 sock->state = SS_UNCONNECTED;
557 sock->ops = &pptp_ops;
558
559 sk->sk_backlog_rcv = pptp_rcv_core;
560 sk->sk_state = PPPOX_NONE;
561 sk->sk_type = SOCK_STREAM;
562 sk->sk_family = PF_PPPOX;
563 sk->sk_protocol = PX_PROTO_PPTP;
564 sk->sk_destruct = pptp_sock_destruct;
565
566 po = pppox_sk(sk);
567 opt = &po->proto.pptp;
568
569 opt->seq_sent = 0; opt->seq_recv = 0xffffffff;
570 opt->ack_recv = 0; opt->ack_sent = 0xffffffff;
571
572 error = 0;
573 out:
574 return error;
575 }
576
pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd, unsigned long arg)577 static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
578 unsigned long arg)
579 {
580 struct sock *sk = (struct sock *) chan->private;
581 struct pppox_sock *po = pppox_sk(sk);
582 struct pptp_opt *opt = &po->proto.pptp;
583 void __user *argp = (void __user *)arg;
584 int __user *p = argp;
585 int err, val;
586
587 err = -EFAULT;
588 switch (cmd) {
589 case PPPIOCGFLAGS:
590 val = opt->ppp_flags;
591 if (put_user(val, p))
592 break;
593 err = 0;
594 break;
595 case PPPIOCSFLAGS:
596 if (get_user(val, p))
597 break;
598 opt->ppp_flags = val & ~SC_RCV_BITS;
599 err = 0;
600 break;
601 default:
602 err = -ENOTTY;
603 }
604
605 return err;
606 }
607
608 static const struct ppp_channel_ops pptp_chan_ops = {
609 .start_xmit = pptp_xmit,
610 .ioctl = pptp_ppp_ioctl,
611 };
612
613 static struct proto pptp_sk_proto __read_mostly = {
614 .name = "PPTP",
615 .owner = THIS_MODULE,
616 .obj_size = sizeof(struct pppox_sock),
617 };
618
619 static const struct proto_ops pptp_ops = {
620 .family = AF_PPPOX,
621 .owner = THIS_MODULE,
622 .release = pptp_release,
623 .bind = pptp_bind,
624 .connect = pptp_connect,
625 .socketpair = sock_no_socketpair,
626 .accept = sock_no_accept,
627 .getname = pptp_getname,
628 .listen = sock_no_listen,
629 .shutdown = sock_no_shutdown,
630 .sendmsg = sock_no_sendmsg,
631 .recvmsg = sock_no_recvmsg,
632 .mmap = sock_no_mmap,
633 .ioctl = pppox_ioctl,
634 #ifdef CONFIG_COMPAT
635 .compat_ioctl = pppox_compat_ioctl,
636 #endif
637 };
638
639 static const struct pppox_proto pppox_pptp_proto = {
640 .create = pptp_create,
641 .owner = THIS_MODULE,
642 };
643
644 static const struct gre_protocol gre_pptp_protocol = {
645 .handler = pptp_rcv,
646 };
647
pptp_init_module(void)648 static int __init pptp_init_module(void)
649 {
650 int err = 0;
651 pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n");
652
653 callid_sock = vzalloc(array_size(sizeof(void *), (MAX_CALLID + 1)));
654 if (!callid_sock)
655 return -ENOMEM;
656
657 err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
658 if (err) {
659 pr_err("PPTP: can't add gre protocol\n");
660 goto out_mem_free;
661 }
662
663 err = proto_register(&pptp_sk_proto, 0);
664 if (err) {
665 pr_err("PPTP: can't register sk_proto\n");
666 goto out_gre_del_protocol;
667 }
668
669 err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto);
670 if (err) {
671 pr_err("PPTP: can't register pppox_proto\n");
672 goto out_unregister_sk_proto;
673 }
674
675 return 0;
676
677 out_unregister_sk_proto:
678 proto_unregister(&pptp_sk_proto);
679 out_gre_del_protocol:
680 gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
681 out_mem_free:
682 vfree(callid_sock);
683
684 return err;
685 }
686
pptp_exit_module(void)687 static void __exit pptp_exit_module(void)
688 {
689 unregister_pppox_proto(PX_PROTO_PPTP);
690 proto_unregister(&pptp_sk_proto);
691 gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
692 vfree(callid_sock);
693 }
694
695 module_init(pptp_init_module);
696 module_exit(pptp_exit_module);
697
698 MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol");
699 MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
700 MODULE_LICENSE("GPL");
701 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_PPTP);
702