2 * Point-to-Point Tunneling Protocol for Linux
4 * Authors: Dmitry Kozlov <xeb@mail.ru>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
13 #include <linux/string.h>
14 #include <linux/module.h>
15 #include <linux/kernel.h>
16 #include <linux/slab.h>
17 #include <linux/errno.h>
18 #include <linux/netdevice.h>
19 #include <linux/net.h>
20 #include <linux/skbuff.h>
21 #include <linux/vmalloc.h>
22 #include <linux/init.h>
23 #include <linux/ppp_channel.h>
24 #include <linux/ppp_defs.h>
25 #include <linux/if_pppox.h>
26 #include <linux/ppp-ioctl.h>
27 #include <linux/notifier.h>
28 #include <linux/file.h>
31 #include <linux/rcupdate.h>
32 #include <linux/spinlock.h>
35 #include <net/protocol.h>
38 #include <net/route.h>
42 #include <linux/uaccess.h>
44 #define PPTP_DRIVER_VERSION "0.8.5"
46 #define MAX_CALLID 65535
48 static DECLARE_BITMAP(callid_bitmap
, MAX_CALLID
+ 1);
49 static struct pppox_sock __rcu
**callid_sock
;
51 static DEFINE_SPINLOCK(chan_lock
);
53 static struct proto pptp_sk_proto __read_mostly
;
54 static const struct ppp_channel_ops pptp_chan_ops
;
55 static const struct proto_ops pptp_ops
;
57 static struct pppox_sock
*lookup_chan(u16 call_id
, __be32 s_addr
)
59 struct pppox_sock
*sock
;
63 sock
= rcu_dereference(callid_sock
[call_id
]);
65 opt
= &sock
->proto
.pptp
;
66 if (opt
->dst_addr
.sin_addr
.s_addr
!= s_addr
)
69 sock_hold(sk_pppox(sock
));
76 static int lookup_chan_dst(u16 call_id
, __be32 d_addr
)
78 struct pppox_sock
*sock
;
84 for_each_set_bit_from(i
, callid_bitmap
, MAX_CALLID
) {
85 sock
= rcu_dereference(callid_sock
[i
]);
88 opt
= &sock
->proto
.pptp
;
89 if (opt
->dst_addr
.call_id
== call_id
&&
90 opt
->dst_addr
.sin_addr
.s_addr
== d_addr
)
95 return i
< MAX_CALLID
;
98 static int add_chan(struct pppox_sock
*sock
,
103 spin_lock(&chan_lock
);
105 call_id
= find_next_zero_bit(callid_bitmap
, MAX_CALLID
, call_id
+ 1);
106 if (call_id
== MAX_CALLID
) {
107 call_id
= find_next_zero_bit(callid_bitmap
, MAX_CALLID
, 1);
108 if (call_id
== MAX_CALLID
)
111 sa
->call_id
= call_id
;
112 } else if (test_bit(sa
->call_id
, callid_bitmap
)) {
116 sock
->proto
.pptp
.src_addr
= *sa
;
117 set_bit(sa
->call_id
, callid_bitmap
);
118 rcu_assign_pointer(callid_sock
[sa
->call_id
], sock
);
119 spin_unlock(&chan_lock
);
124 spin_unlock(&chan_lock
);
128 static void del_chan(struct pppox_sock
*sock
)
130 spin_lock(&chan_lock
);
131 clear_bit(sock
->proto
.pptp
.src_addr
.call_id
, callid_bitmap
);
132 RCU_INIT_POINTER(callid_sock
[sock
->proto
.pptp
.src_addr
.call_id
], NULL
);
133 spin_unlock(&chan_lock
);
137 static int pptp_xmit(struct ppp_channel
*chan
, struct sk_buff
*skb
)
139 struct sock
*sk
= (struct sock
*) chan
->private;
140 struct pppox_sock
*po
= pppox_sk(sk
);
141 struct net
*net
= sock_net(sk
);
142 struct pptp_opt
*opt
= &po
->proto
.pptp
;
143 struct pptp_gre_header
*hdr
;
144 unsigned int header_len
= sizeof(*hdr
);
153 struct net_device
*tdev
;
157 if (sk_pppox(po
)->sk_state
& PPPOX_DEAD
)
160 rt
= ip_route_output_ports(net
, &fl4
, NULL
,
161 opt
->dst_addr
.sin_addr
.s_addr
,
162 opt
->src_addr
.sin_addr
.s_addr
,
170 max_headroom
= LL_RESERVED_SPACE(tdev
) + sizeof(*iph
) + sizeof(*hdr
) + 2;
172 if (skb_headroom(skb
) < max_headroom
|| skb_cloned(skb
) || skb_shared(skb
)) {
173 struct sk_buff
*new_skb
= skb_realloc_headroom(skb
, max_headroom
);
179 skb_set_owner_w(new_skb
, skb
->sk
);
185 islcp
= ((data
[0] << 8) + data
[1]) == PPP_LCP
&& 1 <= data
[2] && data
[2] <= 7;
187 /* compress protocol field */
188 if ((opt
->ppp_flags
& SC_COMP_PROT
) && data
[0] == 0 && !islcp
)
191 /* Put in the address/control bytes if necessary */
192 if ((opt
->ppp_flags
& SC_COMP_AC
) == 0 || islcp
) {
193 data
= skb_push(skb
, 2);
194 data
[0] = PPP_ALLSTATIONS
;
200 seq_recv
= opt
->seq_recv
;
202 if (opt
->ack_sent
== seq_recv
)
203 header_len
-= sizeof(hdr
->ack
);
205 /* Push down and install GRE header */
206 skb_push(skb
, header_len
);
207 hdr
= (struct pptp_gre_header
*)(skb
->data
);
209 hdr
->gre_hd
.flags
= GRE_KEY
| GRE_VERSION_1
| GRE_SEQ
;
210 hdr
->gre_hd
.protocol
= GRE_PROTO_PPP
;
211 hdr
->call_id
= htons(opt
->dst_addr
.call_id
);
213 hdr
->seq
= htonl(++opt
->seq_sent
);
214 if (opt
->ack_sent
!= seq_recv
) {
215 /* send ack with this message */
216 hdr
->gre_hd
.flags
|= GRE_ACK
;
217 hdr
->ack
= htonl(seq_recv
);
218 opt
->ack_sent
= seq_recv
;
220 hdr
->payload_len
= htons(len
);
222 /* Push down and install the IP header. */
224 skb_reset_transport_header(skb
);
225 skb_push(skb
, sizeof(*iph
));
226 skb_reset_network_header(skb
);
227 memset(&(IPCB(skb
)->opt
), 0, sizeof(IPCB(skb
)->opt
));
228 IPCB(skb
)->flags
&= ~(IPSKB_XFRM_TUNNEL_SIZE
| IPSKB_XFRM_TRANSFORMED
| IPSKB_REROUTED
);
232 iph
->ihl
= sizeof(struct iphdr
) >> 2;
233 if (ip_dont_fragment(sk
, &rt
->dst
))
234 iph
->frag_off
= htons(IP_DF
);
237 iph
->protocol
= IPPROTO_GRE
;
239 iph
->daddr
= fl4
.daddr
;
240 iph
->saddr
= fl4
.saddr
;
241 iph
->ttl
= ip4_dst_hoplimit(&rt
->dst
);
242 iph
->tot_len
= htons(skb
->len
);
245 skb_dst_set(skb
, &rt
->dst
);
249 skb
->ip_summed
= CHECKSUM_NONE
;
250 ip_select_ident(net
, skb
, NULL
);
253 ip_local_out(net
, skb
->sk
, skb
);
261 static int pptp_rcv_core(struct sock
*sk
, struct sk_buff
*skb
)
263 struct pppox_sock
*po
= pppox_sk(sk
);
264 struct pptp_opt
*opt
= &po
->proto
.pptp
;
265 int headersize
, payload_len
, seq
;
267 struct pptp_gre_header
*header
;
269 if (!(sk
->sk_state
& PPPOX_CONNECTED
)) {
270 if (sock_queue_rcv_skb(sk
, skb
))
272 return NET_RX_SUCCESS
;
275 header
= (struct pptp_gre_header
*)(skb
->data
);
276 headersize
= sizeof(*header
);
278 /* test if acknowledgement present */
279 if (GRE_IS_ACK(header
->gre_hd
.flags
)) {
282 if (!pskb_may_pull(skb
, headersize
))
284 header
= (struct pptp_gre_header
*)(skb
->data
);
286 /* ack in different place if S = 0 */
287 ack
= GRE_IS_SEQ(header
->gre_hd
.flags
) ? header
->ack
: header
->seq
;
291 if (ack
> opt
->ack_recv
)
293 /* also handle sequence number wrap-around */
294 if (WRAPPED(ack
, opt
->ack_recv
))
297 headersize
-= sizeof(header
->ack
);
299 /* test if payload present */
300 if (!GRE_IS_SEQ(header
->gre_hd
.flags
))
303 payload_len
= ntohs(header
->payload_len
);
304 seq
= ntohl(header
->seq
);
306 /* check for incomplete packet (length smaller than expected) */
307 if (!pskb_may_pull(skb
, headersize
+ payload_len
))
310 payload
= skb
->data
+ headersize
;
311 /* check for expected sequence number */
312 if (seq
< opt
->seq_recv
+ 1 || WRAPPED(opt
->seq_recv
, seq
)) {
313 if ((payload
[0] == PPP_ALLSTATIONS
) && (payload
[1] == PPP_UI
) &&
314 (PPP_PROTOCOL(payload
) == PPP_LCP
) &&
315 ((payload
[4] == PPP_LCP_ECHOREQ
) || (payload
[4] == PPP_LCP_ECHOREP
)))
320 skb_pull(skb
, headersize
);
322 if (payload
[0] == PPP_ALLSTATIONS
&& payload
[1] == PPP_UI
) {
323 /* chop off address/control */
329 if ((*skb
->data
) & 1) {
330 /* protocol is compressed */
331 *(u8
*)skb_push(skb
, 1) = 0;
334 skb
->ip_summed
= CHECKSUM_NONE
;
335 skb_set_network_header(skb
, skb
->head
-skb
->data
);
336 ppp_input(&po
->chan
, skb
);
338 return NET_RX_SUCCESS
;
345 static int pptp_rcv(struct sk_buff
*skb
)
347 struct pppox_sock
*po
;
348 struct pptp_gre_header
*header
;
351 if (skb
->pkt_type
!= PACKET_HOST
)
354 if (!pskb_may_pull(skb
, 12))
359 header
= (struct pptp_gre_header
*)skb
->data
;
361 if (header
->gre_hd
.protocol
!= GRE_PROTO_PPP
|| /* PPTP-GRE protocol for PPTP */
362 GRE_IS_CSUM(header
->gre_hd
.flags
) || /* flag CSUM should be clear */
363 GRE_IS_ROUTING(header
->gre_hd
.flags
) || /* flag ROUTING should be clear */
364 !GRE_IS_KEY(header
->gre_hd
.flags
) || /* flag KEY should be set */
365 (header
->gre_hd
.flags
& GRE_FLAGS
)) /* flag Recursion Ctrl should be clear */
366 /* if invalid, discard this packet */
369 po
= lookup_chan(htons(header
->call_id
), iph
->saddr
);
373 return sk_receive_skb(sk_pppox(po
), skb
, 0);
380 static int pptp_bind(struct socket
*sock
, struct sockaddr
*uservaddr
,
383 struct sock
*sk
= sock
->sk
;
384 struct sockaddr_pppox
*sp
= (struct sockaddr_pppox
*) uservaddr
;
385 struct pppox_sock
*po
= pppox_sk(sk
);
388 if (sockaddr_len
< sizeof(struct sockaddr_pppox
))
393 if (sk
->sk_state
& PPPOX_DEAD
) {
398 if (sk
->sk_state
& PPPOX_BOUND
) {
403 if (add_chan(po
, &sp
->sa_addr
.pptp
))
406 sk
->sk_state
|= PPPOX_BOUND
;
413 static int pptp_connect(struct socket
*sock
, struct sockaddr
*uservaddr
,
414 int sockaddr_len
, int flags
)
416 struct sock
*sk
= sock
->sk
;
417 struct sockaddr_pppox
*sp
= (struct sockaddr_pppox
*) uservaddr
;
418 struct pppox_sock
*po
= pppox_sk(sk
);
419 struct pptp_opt
*opt
= &po
->proto
.pptp
;
424 if (sockaddr_len
< sizeof(struct sockaddr_pppox
))
427 if (sp
->sa_protocol
!= PX_PROTO_PPTP
)
430 if (lookup_chan_dst(sp
->sa_addr
.pptp
.call_id
, sp
->sa_addr
.pptp
.sin_addr
.s_addr
))
434 /* Check for already bound sockets */
435 if (sk
->sk_state
& PPPOX_CONNECTED
) {
440 /* Check for already disconnected sockets, on attempts to disconnect */
441 if (sk
->sk_state
& PPPOX_DEAD
) {
446 if (!opt
->src_addr
.sin_addr
.s_addr
|| !sp
->sa_addr
.pptp
.sin_addr
.s_addr
) {
451 po
->chan
.private = sk
;
452 po
->chan
.ops
= &pptp_chan_ops
;
454 rt
= ip_route_output_ports(sock_net(sk
), &fl4
, sk
,
455 opt
->dst_addr
.sin_addr
.s_addr
,
456 opt
->src_addr
.sin_addr
.s_addr
,
458 IPPROTO_GRE
, RT_CONN_FLAGS(sk
), 0);
460 error
= -EHOSTUNREACH
;
463 sk_setup_caps(sk
, &rt
->dst
);
465 po
->chan
.mtu
= dst_mtu(&rt
->dst
);
467 po
->chan
.mtu
= PPP_MRU
;
469 po
->chan
.mtu
-= PPTP_HEADER_OVERHEAD
;
471 po
->chan
.hdrlen
= 2 + sizeof(struct pptp_gre_header
);
472 error
= ppp_register_channel(&po
->chan
);
474 pr_err("PPTP: failed to register PPP channel (%d)\n", error
);
478 opt
->dst_addr
= sp
->sa_addr
.pptp
;
479 sk
->sk_state
|= PPPOX_CONNECTED
;
486 static int pptp_getname(struct socket
*sock
, struct sockaddr
*uaddr
,
487 int *usockaddr_len
, int peer
)
489 int len
= sizeof(struct sockaddr_pppox
);
490 struct sockaddr_pppox sp
;
492 memset(&sp
.sa_addr
, 0, sizeof(sp
.sa_addr
));
494 sp
.sa_family
= AF_PPPOX
;
495 sp
.sa_protocol
= PX_PROTO_PPTP
;
496 sp
.sa_addr
.pptp
= pppox_sk(sock
->sk
)->proto
.pptp
.src_addr
;
498 memcpy(uaddr
, &sp
, len
);
500 *usockaddr_len
= len
;
505 static int pptp_release(struct socket
*sock
)
507 struct sock
*sk
= sock
->sk
;
508 struct pppox_sock
*po
;
516 if (sock_flag(sk
, SOCK_DEAD
)) {
524 pppox_unbind_sock(sk
);
525 sk
->sk_state
= PPPOX_DEAD
;
536 static void pptp_sock_destruct(struct sock
*sk
)
538 if (!(sk
->sk_state
& PPPOX_DEAD
)) {
539 del_chan(pppox_sk(sk
));
540 pppox_unbind_sock(sk
);
542 skb_queue_purge(&sk
->sk_receive_queue
);
545 static int pptp_create(struct net
*net
, struct socket
*sock
, int kern
)
549 struct pppox_sock
*po
;
550 struct pptp_opt
*opt
;
552 sk
= sk_alloc(net
, PF_PPPOX
, GFP_KERNEL
, &pptp_sk_proto
, kern
);
556 sock_init_data(sock
, sk
);
558 sock
->state
= SS_UNCONNECTED
;
559 sock
->ops
= &pptp_ops
;
561 sk
->sk_backlog_rcv
= pptp_rcv_core
;
562 sk
->sk_state
= PPPOX_NONE
;
563 sk
->sk_type
= SOCK_STREAM
;
564 sk
->sk_family
= PF_PPPOX
;
565 sk
->sk_protocol
= PX_PROTO_PPTP
;
566 sk
->sk_destruct
= pptp_sock_destruct
;
569 opt
= &po
->proto
.pptp
;
571 opt
->seq_sent
= 0; opt
->seq_recv
= 0xffffffff;
572 opt
->ack_recv
= 0; opt
->ack_sent
= 0xffffffff;
579 static int pptp_ppp_ioctl(struct ppp_channel
*chan
, unsigned int cmd
,
582 struct sock
*sk
= (struct sock
*) chan
->private;
583 struct pppox_sock
*po
= pppox_sk(sk
);
584 struct pptp_opt
*opt
= &po
->proto
.pptp
;
585 void __user
*argp
= (void __user
*)arg
;
586 int __user
*p
= argp
;
592 val
= opt
->ppp_flags
;
593 if (put_user(val
, p
))
598 if (get_user(val
, p
))
600 opt
->ppp_flags
= val
& ~SC_RCV_BITS
;
610 static const struct ppp_channel_ops pptp_chan_ops
= {
611 .start_xmit
= pptp_xmit
,
612 .ioctl
= pptp_ppp_ioctl
,
615 static struct proto pptp_sk_proto __read_mostly
= {
617 .owner
= THIS_MODULE
,
618 .obj_size
= sizeof(struct pppox_sock
),
621 static const struct proto_ops pptp_ops
= {
623 .owner
= THIS_MODULE
,
624 .release
= pptp_release
,
626 .connect
= pptp_connect
,
627 .socketpair
= sock_no_socketpair
,
628 .accept
= sock_no_accept
,
629 .getname
= pptp_getname
,
630 .poll
= sock_no_poll
,
631 .listen
= sock_no_listen
,
632 .shutdown
= sock_no_shutdown
,
633 .setsockopt
= sock_no_setsockopt
,
634 .getsockopt
= sock_no_getsockopt
,
635 .sendmsg
= sock_no_sendmsg
,
636 .recvmsg
= sock_no_recvmsg
,
637 .mmap
= sock_no_mmap
,
638 .ioctl
= pppox_ioctl
,
641 static const struct pppox_proto pppox_pptp_proto
= {
642 .create
= pptp_create
,
643 .owner
= THIS_MODULE
,
646 static const struct gre_protocol gre_pptp_protocol
= {
650 static int __init
pptp_init_module(void)
653 pr_info("PPTP driver version " PPTP_DRIVER_VERSION
"\n");
655 callid_sock
= vzalloc((MAX_CALLID
+ 1) * sizeof(void *));
659 err
= gre_add_protocol(&gre_pptp_protocol
, GREPROTO_PPTP
);
661 pr_err("PPTP: can't add gre protocol\n");
665 err
= proto_register(&pptp_sk_proto
, 0);
667 pr_err("PPTP: can't register sk_proto\n");
668 goto out_gre_del_protocol
;
671 err
= register_pppox_proto(PX_PROTO_PPTP
, &pppox_pptp_proto
);
673 pr_err("PPTP: can't register pppox_proto\n");
674 goto out_unregister_sk_proto
;
679 out_unregister_sk_proto
:
680 proto_unregister(&pptp_sk_proto
);
681 out_gre_del_protocol
:
682 gre_del_protocol(&gre_pptp_protocol
, GREPROTO_PPTP
);
689 static void __exit
pptp_exit_module(void)
691 unregister_pppox_proto(PX_PROTO_PPTP
);
692 proto_unregister(&pptp_sk_proto
);
693 gre_del_protocol(&gre_pptp_protocol
, GREPROTO_PPTP
);
697 module_init(pptp_init_module
);
698 module_exit(pptp_exit_module
);
700 MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol");
701 MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
702 MODULE_LICENSE("GPL");
703 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX
, PX_PROTO_PPTP
);