xref: /linux/drivers/net/ppp/pptp.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
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(const struct pppox_sock * po,struct flowi4 * fl4)132 static struct rtable *pptp_route_output(const struct pppox_sock *po,
133 					struct flowi4 *fl4)
134 {
135 	const 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 = 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) ? ntohl(header->ack) :
296 							 ntohl(header->seq);
297 		if (ack > opt->ack_recv)
298 			opt->ack_recv = ack;
299 		/* also handle sequence number wrap-around  */
300 		if (WRAPPED(ack, opt->ack_recv))
301 			opt->ack_recv = ack;
302 	} else {
303 		headersize -= sizeof(header->ack);
304 	}
305 	/* test if payload present */
306 	if (!GRE_IS_SEQ(header->gre_hd.flags))
307 		goto drop;
308 
309 	payload_len = ntohs(header->payload_len);
310 	seq         = ntohl(header->seq);
311 
312 	/* check for incomplete packet (length smaller than expected) */
313 	if (!pskb_may_pull(skb, headersize + payload_len))
314 		goto drop;
315 
316 	payload = skb->data + headersize;
317 	/* check for expected sequence number */
318 	if (seq < opt->seq_recv + 1 || WRAPPED(opt->seq_recv, seq)) {
319 		if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) &&
320 				(PPP_PROTOCOL(payload) == PPP_LCP) &&
321 				((payload[4] == PPP_LCP_ECHOREQ) || (payload[4] == PPP_LCP_ECHOREP)))
322 			goto allow_packet;
323 	} else {
324 		opt->seq_recv = seq;
325 allow_packet:
326 		skb_pull(skb, headersize);
327 
328 		if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) {
329 			/* chop off address/control */
330 			if (skb->len < 3)
331 				goto drop;
332 			skb_pull(skb, 2);
333 		}
334 
335 		skb->ip_summed = CHECKSUM_NONE;
336 		skb_set_network_header(skb, skb->head-skb->data);
337 		ppp_input(&po->chan, skb);
338 
339 		return NET_RX_SUCCESS;
340 	}
341 drop:
342 	kfree_skb(skb);
343 	return NET_RX_DROP;
344 }
345 
pptp_rcv(struct sk_buff * skb)346 static int pptp_rcv(struct sk_buff *skb)
347 {
348 	struct pppox_sock *po;
349 	struct pptp_gre_header *header;
350 	struct iphdr *iph;
351 
352 	if (skb->pkt_type != PACKET_HOST)
353 		goto drop;
354 
355 	if (!pskb_may_pull(skb, 12))
356 		goto drop;
357 
358 	iph = ip_hdr(skb);
359 
360 	header = (struct pptp_gre_header *)skb->data;
361 
362 	if (header->gre_hd.protocol != GRE_PROTO_PPP || /* PPTP-GRE protocol for PPTP */
363 		GRE_IS_CSUM(header->gre_hd.flags) ||    /* flag CSUM should be clear */
364 		GRE_IS_ROUTING(header->gre_hd.flags) || /* flag ROUTING should be clear */
365 		!GRE_IS_KEY(header->gre_hd.flags) ||    /* flag KEY should be set */
366 		(header->gre_hd.flags & GRE_FLAGS))     /* flag Recursion Ctrl should be clear */
367 		/* if invalid, discard this packet */
368 		goto drop;
369 
370 	po = lookup_chan(ntohs(header->call_id), iph->saddr);
371 	if (po) {
372 		skb_dst_drop(skb);
373 		nf_reset_ct(skb);
374 		return sk_receive_skb(sk_pppox(po), skb, 0);
375 	}
376 drop:
377 	kfree_skb(skb);
378 	return NET_RX_DROP;
379 }
380 
pptp_bind(struct socket * sock,struct sockaddr * uservaddr,int sockaddr_len)381 static int pptp_bind(struct socket *sock, struct sockaddr *uservaddr,
382 	int sockaddr_len)
383 {
384 	struct sock *sk = sock->sk;
385 	struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
386 	struct pppox_sock *po = pppox_sk(sk);
387 	int error = 0;
388 
389 	if (sockaddr_len < sizeof(struct sockaddr_pppox))
390 		return -EINVAL;
391 
392 	lock_sock(sk);
393 
394 	if (sk->sk_state & PPPOX_DEAD) {
395 		error = -EALREADY;
396 		goto out;
397 	}
398 
399 	if (sk->sk_state & PPPOX_BOUND) {
400 		error = -EBUSY;
401 		goto out;
402 	}
403 
404 	if (add_chan(po, &sp->sa_addr.pptp))
405 		error = -EBUSY;
406 	else
407 		sk->sk_state |= PPPOX_BOUND;
408 
409 out:
410 	release_sock(sk);
411 	return error;
412 }
413 
pptp_connect(struct socket * sock,struct sockaddr * uservaddr,int sockaddr_len,int flags)414 static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr,
415 	int sockaddr_len, int flags)
416 {
417 	struct sock *sk = sock->sk;
418 	struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
419 	struct pppox_sock *po = pppox_sk(sk);
420 	struct pptp_opt *opt = &po->proto.pptp;
421 	struct rtable *rt;
422 	struct flowi4 fl4;
423 	int error = 0;
424 
425 	if (sockaddr_len < sizeof(struct sockaddr_pppox))
426 		return -EINVAL;
427 
428 	if (sp->sa_protocol != PX_PROTO_PPTP)
429 		return -EINVAL;
430 
431 	if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr))
432 		return -EALREADY;
433 
434 	lock_sock(sk);
435 	/* Check for already bound sockets */
436 	if (sk->sk_state & PPPOX_CONNECTED) {
437 		error = -EBUSY;
438 		goto end;
439 	}
440 
441 	/* Check for already disconnected sockets, on attempts to disconnect */
442 	if (sk->sk_state & PPPOX_DEAD) {
443 		error = -EALREADY;
444 		goto end;
445 	}
446 
447 	if (!opt->src_addr.sin_addr.s_addr || !sp->sa_addr.pptp.sin_addr.s_addr) {
448 		error = -EINVAL;
449 		goto end;
450 	}
451 
452 	po->chan.private = sk;
453 	po->chan.ops = &pptp_chan_ops;
454 
455 	rt = pptp_route_output(po, &fl4);
456 	if (IS_ERR(rt)) {
457 		error = -EHOSTUNREACH;
458 		goto end;
459 	}
460 	sk_setup_caps(sk, &rt->dst);
461 
462 	po->chan.mtu = dst_mtu(&rt->dst);
463 	if (!po->chan.mtu)
464 		po->chan.mtu = PPP_MRU;
465 	po->chan.mtu -= PPTP_HEADER_OVERHEAD;
466 
467 	po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header);
468 	error = ppp_register_channel(&po->chan);
469 	if (error) {
470 		pr_err("PPTP: failed to register PPP channel (%d)\n", error);
471 		goto end;
472 	}
473 
474 	opt->dst_addr = sp->sa_addr.pptp;
475 	sk->sk_state |= PPPOX_CONNECTED;
476 
477  end:
478 	release_sock(sk);
479 	return error;
480 }
481 
pptp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)482 static int pptp_getname(struct socket *sock, struct sockaddr *uaddr,
483 	int peer)
484 {
485 	int len = sizeof(struct sockaddr_pppox);
486 	struct sockaddr_pppox sp;
487 
488 	memset(&sp.sa_addr, 0, sizeof(sp.sa_addr));
489 
490 	sp.sa_family    = AF_PPPOX;
491 	sp.sa_protocol  = PX_PROTO_PPTP;
492 	sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr;
493 
494 	memcpy(uaddr, &sp, len);
495 
496 	return len;
497 }
498 
pptp_release(struct socket * sock)499 static int pptp_release(struct socket *sock)
500 {
501 	struct sock *sk = sock->sk;
502 	struct pppox_sock *po;
503 	int error = 0;
504 
505 	if (!sk)
506 		return 0;
507 
508 	lock_sock(sk);
509 
510 	if (sock_flag(sk, SOCK_DEAD)) {
511 		release_sock(sk);
512 		return -EBADF;
513 	}
514 
515 	po = pppox_sk(sk);
516 	del_chan(po);
517 	synchronize_rcu();
518 
519 	pppox_unbind_sock(sk);
520 	sk->sk_state = PPPOX_DEAD;
521 
522 	sock_orphan(sk);
523 	sock->sk = NULL;
524 
525 	release_sock(sk);
526 	sock_put(sk);
527 
528 	return error;
529 }
530 
pptp_sock_destruct(struct sock * sk)531 static void pptp_sock_destruct(struct sock *sk)
532 {
533 	if (!(sk->sk_state & PPPOX_DEAD)) {
534 		del_chan(pppox_sk(sk));
535 		pppox_unbind_sock(sk);
536 	}
537 	skb_queue_purge(&sk->sk_receive_queue);
538 	dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));
539 }
540 
pptp_create(struct net * net,struct socket * sock,int kern)541 static int pptp_create(struct net *net, struct socket *sock, int kern)
542 {
543 	int error = -ENOMEM;
544 	struct sock *sk;
545 	struct pppox_sock *po;
546 	struct pptp_opt *opt;
547 
548 	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, kern);
549 	if (!sk)
550 		goto out;
551 
552 	sock_init_data(sock, sk);
553 
554 	sock->state = SS_UNCONNECTED;
555 	sock->ops   = &pptp_ops;
556 
557 	sk->sk_backlog_rcv = pptp_rcv_core;
558 	sk->sk_state       = PPPOX_NONE;
559 	sk->sk_type        = SOCK_STREAM;
560 	sk->sk_family      = PF_PPPOX;
561 	sk->sk_protocol    = PX_PROTO_PPTP;
562 	sk->sk_destruct    = pptp_sock_destruct;
563 
564 	po = pppox_sk(sk);
565 	opt = &po->proto.pptp;
566 
567 	opt->seq_sent = 0; opt->seq_recv = 0xffffffff;
568 	opt->ack_recv = 0; opt->ack_sent = 0xffffffff;
569 
570 	error = 0;
571 out:
572 	return error;
573 }
574 
pptp_ppp_ioctl(struct ppp_channel * chan,unsigned int cmd,unsigned long arg)575 static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
576 	unsigned long arg)
577 {
578 	struct sock *sk = chan->private;
579 	struct pppox_sock *po = pppox_sk(sk);
580 	struct pptp_opt *opt = &po->proto.pptp;
581 	void __user *argp = (void __user *)arg;
582 	int __user *p = argp;
583 	int err, val;
584 
585 	err = -EFAULT;
586 	switch (cmd) {
587 	case PPPIOCGFLAGS:
588 		val = opt->ppp_flags;
589 		if (put_user(val, p))
590 			break;
591 		err = 0;
592 		break;
593 	case PPPIOCSFLAGS:
594 		if (get_user(val, p))
595 			break;
596 		opt->ppp_flags = val & ~SC_RCV_BITS;
597 		err = 0;
598 		break;
599 	default:
600 		err = -ENOTTY;
601 	}
602 
603 	return err;
604 }
605 
606 static const struct ppp_channel_ops pptp_chan_ops = {
607 	.start_xmit = pptp_xmit,
608 	.ioctl      = pptp_ppp_ioctl,
609 };
610 
611 static struct proto pptp_sk_proto __read_mostly = {
612 	.name     = "PPTP",
613 	.owner    = THIS_MODULE,
614 	.obj_size = sizeof(struct pppox_sock),
615 };
616 
617 static const struct proto_ops pptp_ops = {
618 	.family     = AF_PPPOX,
619 	.owner      = THIS_MODULE,
620 	.release    = pptp_release,
621 	.bind       = pptp_bind,
622 	.connect    = pptp_connect,
623 	.socketpair = sock_no_socketpair,
624 	.accept     = sock_no_accept,
625 	.getname    = pptp_getname,
626 	.listen     = sock_no_listen,
627 	.shutdown   = sock_no_shutdown,
628 	.sendmsg    = sock_no_sendmsg,
629 	.recvmsg    = sock_no_recvmsg,
630 	.mmap       = sock_no_mmap,
631 	.ioctl      = pppox_ioctl,
632 #ifdef CONFIG_COMPAT
633 	.compat_ioctl = pppox_compat_ioctl,
634 #endif
635 };
636 
637 static const struct pppox_proto pppox_pptp_proto = {
638 	.create = pptp_create,
639 	.owner  = THIS_MODULE,
640 };
641 
642 static const struct gre_protocol gre_pptp_protocol = {
643 	.handler = pptp_rcv,
644 };
645 
pptp_init_module(void)646 static int __init pptp_init_module(void)
647 {
648 	int err = 0;
649 	pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n");
650 
651 	callid_sock = vzalloc(array_size(sizeof(void *), (MAX_CALLID + 1)));
652 	if (!callid_sock)
653 		return -ENOMEM;
654 
655 	err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
656 	if (err) {
657 		pr_err("PPTP: can't add gre protocol\n");
658 		goto out_mem_free;
659 	}
660 
661 	err = proto_register(&pptp_sk_proto, 0);
662 	if (err) {
663 		pr_err("PPTP: can't register sk_proto\n");
664 		goto out_gre_del_protocol;
665 	}
666 
667 	err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto);
668 	if (err) {
669 		pr_err("PPTP: can't register pppox_proto\n");
670 		goto out_unregister_sk_proto;
671 	}
672 
673 	return 0;
674 
675 out_unregister_sk_proto:
676 	proto_unregister(&pptp_sk_proto);
677 out_gre_del_protocol:
678 	gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
679 out_mem_free:
680 	vfree(callid_sock);
681 
682 	return err;
683 }
684 
pptp_exit_module(void)685 static void __exit pptp_exit_module(void)
686 {
687 	unregister_pppox_proto(PX_PROTO_PPTP);
688 	proto_unregister(&pptp_sk_proto);
689 	gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
690 	vfree(callid_sock);
691 }
692 
693 module_init(pptp_init_module);
694 module_exit(pptp_exit_module);
695 
696 MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol");
697 MODULE_AUTHOR("D. Kozlov <xeb@mail.ru>");
698 MODULE_LICENSE("GPL");
699 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_PPTP);
700