2 * ip_conntrack_pptp.c - Version 3.0
4 * Connection tracking support for PPTP (Point to Point Tunneling Protocol).
5 * PPTP is a a protocol for creating virtual private networks.
6 * It is a specification defined by Microsoft and some vendors
7 * working with Microsoft. PPTP is built on top of a modified
8 * version of the Internet Generic Routing Encapsulation Protocol.
9 * GRE is defined in RFC 1701 and RFC 1702. Documentation of
10 * PPTP can be found in RFC 2637
12 * (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
14 * Development of this code funded by Astaro AG (http://www.astaro.com/)
17 * - We blindly assume that control connections are always
18 * established in PNS->PAC direction. This is a violation
20 * - We can only support one single call within each session
23 * - testing of incoming PPTP calls
26 * 2002-02-05 - Version 1.3
27 * - Call ip_conntrack_unexpect_related() from
28 * pptp_destroy_siblings() to destroy expectations in case
29 * CALL_DISCONNECT_NOTIFY or tcp fin packet was seen
30 * (Philip Craig <philipc@snapgear.com>)
31 * - Add Version information at module loadtime
32 * 2002-02-10 - Version 1.6
33 * - move to C99 style initializers
34 * - remove second expectation if first arrives
35 * 2004-10-22 - Version 2.0
36 * - merge Mandrake's 2.6.x port with recent 2.6.x API changes
37 * - fix lots of linear skb assumptions from Mandrake's port
38 * 2005-06-10 - Version 2.1
39 * - use ip_conntrack_expect_free() instead of kfree() on the
40 * expect's (which are from the slab for quite some time)
41 * 2005-06-10 - Version 3.0
42 * - port helper to post-2.6.11 API changes,
43 * funded by Oxcoda NetBox Blue (http://www.netboxblue.com/)
44 * 2005-07-30 - Version 3.1
45 * - port helper to 2.6.13 API changes
49 #include <linux/config.h>
50 #include <linux/module.h>
51 #include <linux/netfilter.h>
53 #include <net/checksum.h>
56 #include <linux/netfilter_ipv4/ip_conntrack.h>
57 #include <linux/netfilter_ipv4/ip_conntrack_core.h>
58 #include <linux/netfilter_ipv4/ip_conntrack_helper.h>
59 #include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h>
60 #include <linux/netfilter_ipv4/ip_conntrack_pptp.h>
62 #define IP_CT_PPTP_VERSION "3.1"
64 MODULE_LICENSE("GPL");
65 MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
66 MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP");
68 static DEFINE_SPINLOCK(ip_pptp_lock
);
71 (*ip_nat_pptp_hook_outbound
)(struct sk_buff
**pskb
,
72 struct ip_conntrack
*ct
,
73 enum ip_conntrack_info ctinfo
,
74 struct PptpControlHeader
*ctlh
,
75 union pptp_ctrl_union
*pptpReq
);
78 (*ip_nat_pptp_hook_inbound
)(struct sk_buff
**pskb
,
79 struct ip_conntrack
*ct
,
80 enum ip_conntrack_info ctinfo
,
81 struct PptpControlHeader
*ctlh
,
82 union pptp_ctrl_union
*pptpReq
);
85 (*ip_nat_pptp_hook_exp_gre
)(struct ip_conntrack_expect
*expect_orig
,
86 struct ip_conntrack_expect
*expect_reply
);
89 (*ip_nat_pptp_hook_expectfn
)(struct ip_conntrack
*ct
,
90 struct ip_conntrack_expect
*exp
);
93 /* PptpControlMessageType names */
94 const char *pptp_msg_name
[] = {
96 "START_SESSION_REQUEST",
97 "START_SESSION_REPLY",
98 "STOP_SESSION_REQUEST",
107 "CALL_CLEAR_REQUEST",
108 "CALL_DISCONNECT_NOTIFY",
112 EXPORT_SYMBOL(pptp_msg_name
);
113 #define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, __FUNCTION__, ## args)
115 #define DEBUGP(format, args...)
119 #define MINS * 60 SECS
120 #define HOURS * 60 MINS
122 #define PPTP_GRE_TIMEOUT (10 MINS)
123 #define PPTP_GRE_STREAM_TIMEOUT (5 HOURS)
125 static void pptp_expectfn(struct ip_conntrack
*ct
,
126 struct ip_conntrack_expect
*exp
)
128 DEBUGP("increasing timeouts\n");
130 /* increase timeout of GRE data channel conntrack entry */
131 ct
->proto
.gre
.timeout
= PPTP_GRE_TIMEOUT
;
132 ct
->proto
.gre
.stream_timeout
= PPTP_GRE_STREAM_TIMEOUT
;
134 /* Can you see how rusty this code is, compared with the pre-2.6.11
135 * one? That's what happened to my shiny newnat of 2002 ;( -HW */
137 if (!ip_nat_pptp_hook_expectfn
) {
138 struct ip_conntrack_tuple inv_t
;
139 struct ip_conntrack_expect
*exp_other
;
141 /* obviously this tuple inversion only works until you do NAT */
142 invert_tuplepr(&inv_t
, &exp
->tuple
);
143 DEBUGP("trying to unexpect other dir: ");
146 exp_other
= ip_conntrack_expect_find(&inv_t
);
148 /* delete other expectation. */
150 ip_conntrack_unexpect_related(exp_other
);
151 ip_conntrack_expect_put(exp_other
);
153 DEBUGP("not found\n");
156 /* we need more than simple inversion */
157 ip_nat_pptp_hook_expectfn(ct
, exp
);
161 static int destroy_sibling_or_exp(const struct ip_conntrack_tuple
*t
)
163 struct ip_conntrack_tuple_hash
*h
;
164 struct ip_conntrack_expect
*exp
;
166 DEBUGP("trying to timeout ct or exp for tuple ");
169 h
= ip_conntrack_find_get(t
, NULL
);
171 struct ip_conntrack
*sibling
= tuplehash_to_ctrack(h
);
172 DEBUGP("setting timeout of conntrack %p to 0\n", sibling
);
173 sibling
->proto
.gre
.timeout
= 0;
174 sibling
->proto
.gre
.stream_timeout
= 0;
175 if (del_timer(&sibling
->timeout
))
176 sibling
->timeout
.function((unsigned long)sibling
);
177 ip_conntrack_put(sibling
);
180 exp
= ip_conntrack_expect_find(t
);
182 DEBUGP("unexpect_related of expect %p\n", exp
);
183 ip_conntrack_unexpect_related(exp
);
184 ip_conntrack_expect_put(exp
);
193 /* timeout GRE data connections */
194 static void pptp_destroy_siblings(struct ip_conntrack
*ct
)
196 struct ip_conntrack_tuple t
;
198 /* Since ct->sibling_list has literally rusted away in 2.6.11,
199 * we now need another way to find out about our sibling
200 * contrack and expects... -HW */
202 /* try original (pns->pac) tuple */
203 memcpy(&t
, &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
, sizeof(t
));
204 t
.dst
.protonum
= IPPROTO_GRE
;
205 t
.src
.u
.gre
.key
= htons(ct
->help
.ct_pptp_info
.pns_call_id
);
206 t
.dst
.u
.gre
.key
= htons(ct
->help
.ct_pptp_info
.pac_call_id
);
208 if (!destroy_sibling_or_exp(&t
))
209 DEBUGP("failed to timeout original pns->pac ct/exp\n");
211 /* try reply (pac->pns) tuple */
212 memcpy(&t
, &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
, sizeof(t
));
213 t
.dst
.protonum
= IPPROTO_GRE
;
214 t
.src
.u
.gre
.key
= htons(ct
->help
.ct_pptp_info
.pac_call_id
);
215 t
.dst
.u
.gre
.key
= htons(ct
->help
.ct_pptp_info
.pns_call_id
);
217 if (!destroy_sibling_or_exp(&t
))
218 DEBUGP("failed to timeout reply pac->pns ct/exp\n");
221 /* expect GRE connections (PNS->PAC and PAC->PNS direction) */
223 exp_gre(struct ip_conntrack
*master
,
228 struct ip_conntrack_tuple inv_tuple
;
229 struct ip_conntrack_tuple exp_tuples
[] = {
230 /* tuple in original direction, PNS->PAC */
231 { .src
= { .ip
= master
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.src
.ip
,
232 .u
= { .gre
= { .key
= peer_callid
} }
234 .dst
= { .ip
= master
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.dst
.ip
,
235 .u
= { .gre
= { .key
= callid
} },
236 .protonum
= IPPROTO_GRE
239 /* tuple in reply direction, PAC->PNS */
240 { .src
= { .ip
= master
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.ip
,
241 .u
= { .gre
= { .key
= callid
} }
243 .dst
= { .ip
= master
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.ip
,
244 .u
= { .gre
= { .key
= peer_callid
} },
245 .protonum
= IPPROTO_GRE
249 struct ip_conntrack_expect
*exp_orig
, *exp_reply
;
252 exp_orig
= ip_conntrack_expect_alloc(master
);
253 if (exp_orig
== NULL
)
256 exp_reply
= ip_conntrack_expect_alloc(master
);
257 if (exp_reply
== NULL
)
260 memcpy(&exp_orig
->tuple
, &exp_tuples
[0], sizeof(exp_orig
->tuple
));
262 exp_orig
->mask
.src
.ip
= 0xffffffff;
263 exp_orig
->mask
.src
.u
.all
= 0;
264 exp_orig
->mask
.dst
.u
.all
= 0;
265 exp_orig
->mask
.dst
.u
.gre
.key
= htons(0xffff);
266 exp_orig
->mask
.dst
.ip
= 0xffffffff;
267 exp_orig
->mask
.dst
.protonum
= 0xff;
269 exp_orig
->master
= master
;
270 exp_orig
->expectfn
= pptp_expectfn
;
273 /* both expectations are identical apart from tuple */
274 memcpy(exp_reply
, exp_orig
, sizeof(*exp_reply
));
275 memcpy(&exp_reply
->tuple
, &exp_tuples
[1], sizeof(exp_reply
->tuple
));
277 if (ip_nat_pptp_hook_exp_gre
)
278 ret
= ip_nat_pptp_hook_exp_gre(exp_orig
, exp_reply
);
281 DEBUGP("calling expect_related PNS->PAC");
282 DUMP_TUPLE(&exp_orig
->tuple
);
284 if (ip_conntrack_expect_related(exp_orig
) != 0) {
285 DEBUGP("cannot expect_related()\n");
289 DEBUGP("calling expect_related PAC->PNS");
290 DUMP_TUPLE(&exp_reply
->tuple
);
292 if (ip_conntrack_expect_related(exp_reply
) != 0) {
293 DEBUGP("cannot expect_related()\n");
294 goto out_unexpect_orig
;
297 /* Add GRE keymap entries */
298 if (ip_ct_gre_keymap_add(master
, &exp_reply
->tuple
, 0) != 0) {
299 DEBUGP("cannot keymap_add() exp\n");
300 goto out_unexpect_both
;
303 invert_tuplepr(&inv_tuple
, &exp_reply
->tuple
);
304 if (ip_ct_gre_keymap_add(master
, &inv_tuple
, 1) != 0) {
305 ip_ct_gre_keymap_destroy(master
);
306 DEBUGP("cannot keymap_add() exp_inv\n");
307 goto out_unexpect_both
;
313 ip_conntrack_expect_put(exp_reply
);
315 ip_conntrack_expect_put(exp_orig
);
320 ip_conntrack_unexpect_related(exp_reply
);
322 ip_conntrack_unexpect_related(exp_orig
);
327 pptp_inbound_pkt(struct sk_buff
**pskb
,
329 unsigned int nexthdr_off
,
330 unsigned int datalen
,
331 struct ip_conntrack
*ct
,
332 enum ip_conntrack_info ctinfo
)
334 struct PptpControlHeader _ctlh
, *ctlh
;
336 union pptp_ctrl_union _pptpReq
, *pptpReq
;
337 struct ip_ct_pptp_master
*info
= &ct
->help
.ct_pptp_info
;
342 ctlh
= skb_header_pointer(*pskb
, nexthdr_off
, sizeof(_ctlh
), &_ctlh
);
344 DEBUGP("error during skb_header_pointer\n");
347 nexthdr_off
+= sizeof(_ctlh
);
348 datalen
-= sizeof(_ctlh
);
351 if (reqlen
> sizeof(*pptpReq
))
352 reqlen
= sizeof(*pptpReq
);
353 pptpReq
= skb_header_pointer(*pskb
, nexthdr_off
, reqlen
, &_pptpReq
);
355 DEBUGP("error during skb_header_pointer\n");
359 msg
= ntohs(ctlh
->messageType
);
360 DEBUGP("inbound control message %s\n", pptp_msg_name
[msg
]);
363 case PPTP_START_SESSION_REPLY
:
364 if (reqlen
< sizeof(_pptpReq
.srep
)) {
365 DEBUGP("%s: short packet\n", pptp_msg_name
[msg
]);
369 /* server confirms new control session */
370 if (info
->sstate
< PPTP_SESSION_REQUESTED
) {
371 DEBUGP("%s without START_SESS_REQUEST\n",
375 if (pptpReq
->srep
.resultCode
== PPTP_START_OK
)
376 info
->sstate
= PPTP_SESSION_CONFIRMED
;
378 info
->sstate
= PPTP_SESSION_ERROR
;
381 case PPTP_STOP_SESSION_REPLY
:
382 if (reqlen
< sizeof(_pptpReq
.strep
)) {
383 DEBUGP("%s: short packet\n", pptp_msg_name
[msg
]);
387 /* server confirms end of control session */
388 if (info
->sstate
> PPTP_SESSION_STOPREQ
) {
389 DEBUGP("%s without STOP_SESS_REQUEST\n",
393 if (pptpReq
->strep
.resultCode
== PPTP_STOP_OK
)
394 info
->sstate
= PPTP_SESSION_NONE
;
396 info
->sstate
= PPTP_SESSION_ERROR
;
399 case PPTP_OUT_CALL_REPLY
:
400 if (reqlen
< sizeof(_pptpReq
.ocack
)) {
401 DEBUGP("%s: short packet\n", pptp_msg_name
[msg
]);
405 /* server accepted call, we now expect GRE frames */
406 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
) {
407 DEBUGP("%s but no session\n", pptp_msg_name
[msg
]);
410 if (info
->cstate
!= PPTP_CALL_OUT_REQ
&&
411 info
->cstate
!= PPTP_CALL_OUT_CONF
) {
412 DEBUGP("%s without OUTCALL_REQ\n", pptp_msg_name
[msg
]);
415 if (pptpReq
->ocack
.resultCode
!= PPTP_OUTCALL_CONNECT
) {
416 info
->cstate
= PPTP_CALL_NONE
;
420 cid
= &pptpReq
->ocack
.callID
;
421 pcid
= &pptpReq
->ocack
.peersCallID
;
423 info
->pac_call_id
= ntohs(*cid
);
425 if (htons(info
->pns_call_id
) != *pcid
) {
426 DEBUGP("%s for unknown callid %u\n",
427 pptp_msg_name
[msg
], ntohs(*pcid
));
431 DEBUGP("%s, CID=%X, PCID=%X\n", pptp_msg_name
[msg
],
432 ntohs(*cid
), ntohs(*pcid
));
434 info
->cstate
= PPTP_CALL_OUT_CONF
;
436 seq
= ntohl(tcph
->seq
) + sizeof(struct pptp_pkt_hdr
)
437 + sizeof(struct PptpControlHeader
)
438 + ((void *)pcid
- (void *)pptpReq
);
440 if (exp_gre(ct
, seq
, *cid
, *pcid
) != 0)
441 printk("ip_conntrack_pptp: error during exp_gre\n");
444 case PPTP_IN_CALL_REQUEST
:
445 if (reqlen
< sizeof(_pptpReq
.icack
)) {
446 DEBUGP("%s: short packet\n", pptp_msg_name
[msg
]);
450 /* server tells us about incoming call request */
451 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
) {
452 DEBUGP("%s but no session\n", pptp_msg_name
[msg
]);
455 pcid
= &pptpReq
->icack
.peersCallID
;
456 DEBUGP("%s, PCID=%X\n", pptp_msg_name
[msg
], ntohs(*pcid
));
457 info
->cstate
= PPTP_CALL_IN_REQ
;
458 info
->pac_call_id
= ntohs(*pcid
);
461 case PPTP_IN_CALL_CONNECT
:
462 if (reqlen
< sizeof(_pptpReq
.iccon
)) {
463 DEBUGP("%s: short packet\n", pptp_msg_name
[msg
]);
467 /* server tells us about incoming call established */
468 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
) {
469 DEBUGP("%s but no session\n", pptp_msg_name
[msg
]);
472 if (info
->cstate
!= PPTP_CALL_IN_REP
473 && info
->cstate
!= PPTP_CALL_IN_CONF
) {
474 DEBUGP("%s but never sent IN_CALL_REPLY\n",
479 pcid
= &pptpReq
->iccon
.peersCallID
;
480 cid
= &info
->pac_call_id
;
482 if (info
->pns_call_id
!= ntohs(*pcid
)) {
483 DEBUGP("%s for unknown CallID %u\n",
484 pptp_msg_name
[msg
], ntohs(*pcid
));
488 DEBUGP("%s, PCID=%X\n", pptp_msg_name
[msg
], ntohs(*pcid
));
489 info
->cstate
= PPTP_CALL_IN_CONF
;
491 /* we expect a GRE connection from PAC to PNS */
492 seq
= ntohl(tcph
->seq
) + sizeof(struct pptp_pkt_hdr
)
493 + sizeof(struct PptpControlHeader
)
494 + ((void *)pcid
- (void *)pptpReq
);
496 if (exp_gre(ct
, seq
, *cid
, *pcid
) != 0)
497 printk("ip_conntrack_pptp: error during exp_gre\n");
501 case PPTP_CALL_DISCONNECT_NOTIFY
:
502 if (reqlen
< sizeof(_pptpReq
.disc
)) {
503 DEBUGP("%s: short packet\n", pptp_msg_name
[msg
]);
507 /* server confirms disconnect */
508 cid
= &pptpReq
->disc
.callID
;
509 DEBUGP("%s, CID=%X\n", pptp_msg_name
[msg
], ntohs(*cid
));
510 info
->cstate
= PPTP_CALL_NONE
;
512 /* untrack this call id, unexpect GRE packets */
513 pptp_destroy_siblings(ct
);
516 case PPTP_WAN_ERROR_NOTIFY
:
519 case PPTP_ECHO_REQUEST
:
520 case PPTP_ECHO_REPLY
:
521 /* I don't have to explain these ;) */
524 DEBUGP("invalid %s (TY=%d)\n", (msg
<= PPTP_MSG_MAX
)
525 ? pptp_msg_name
[msg
]:pptp_msg_name
[0], msg
);
530 if (ip_nat_pptp_hook_inbound
)
531 return ip_nat_pptp_hook_inbound(pskb
, ct
, ctinfo
, ctlh
,
539 pptp_outbound_pkt(struct sk_buff
**pskb
,
541 unsigned int nexthdr_off
,
542 unsigned int datalen
,
543 struct ip_conntrack
*ct
,
544 enum ip_conntrack_info ctinfo
)
546 struct PptpControlHeader _ctlh
, *ctlh
;
548 union pptp_ctrl_union _pptpReq
, *pptpReq
;
549 struct ip_ct_pptp_master
*info
= &ct
->help
.ct_pptp_info
;
553 ctlh
= skb_header_pointer(*pskb
, nexthdr_off
, sizeof(_ctlh
), &_ctlh
);
556 nexthdr_off
+= sizeof(_ctlh
);
557 datalen
-= sizeof(_ctlh
);
560 if (reqlen
> sizeof(*pptpReq
))
561 reqlen
= sizeof(*pptpReq
);
562 pptpReq
= skb_header_pointer(*pskb
, nexthdr_off
, reqlen
, &_pptpReq
);
566 msg
= ntohs(ctlh
->messageType
);
567 DEBUGP("outbound control message %s\n", pptp_msg_name
[msg
]);
570 case PPTP_START_SESSION_REQUEST
:
571 /* client requests for new control session */
572 if (info
->sstate
!= PPTP_SESSION_NONE
) {
573 DEBUGP("%s but we already have one",
576 info
->sstate
= PPTP_SESSION_REQUESTED
;
578 case PPTP_STOP_SESSION_REQUEST
:
579 /* client requests end of control session */
580 info
->sstate
= PPTP_SESSION_STOPREQ
;
583 case PPTP_OUT_CALL_REQUEST
:
584 if (reqlen
< sizeof(_pptpReq
.ocreq
)) {
585 DEBUGP("%s: short packet\n", pptp_msg_name
[msg
]);
589 /* client initiating connection to server */
590 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
) {
591 DEBUGP("%s but no session\n",
595 info
->cstate
= PPTP_CALL_OUT_REQ
;
596 /* track PNS call id */
597 cid
= &pptpReq
->ocreq
.callID
;
598 DEBUGP("%s, CID=%X\n", pptp_msg_name
[msg
], ntohs(*cid
));
599 info
->pns_call_id
= ntohs(*cid
);
601 case PPTP_IN_CALL_REPLY
:
602 if (reqlen
< sizeof(_pptpReq
.icack
)) {
603 DEBUGP("%s: short packet\n", pptp_msg_name
[msg
]);
607 /* client answers incoming call */
608 if (info
->cstate
!= PPTP_CALL_IN_REQ
609 && info
->cstate
!= PPTP_CALL_IN_REP
) {
610 DEBUGP("%s without incall_req\n",
614 if (pptpReq
->icack
.resultCode
!= PPTP_INCALL_ACCEPT
) {
615 info
->cstate
= PPTP_CALL_NONE
;
618 pcid
= &pptpReq
->icack
.peersCallID
;
619 if (info
->pac_call_id
!= ntohs(*pcid
)) {
620 DEBUGP("%s for unknown call %u\n",
621 pptp_msg_name
[msg
], ntohs(*pcid
));
624 DEBUGP("%s, CID=%X\n", pptp_msg_name
[msg
], ntohs(*pcid
));
625 /* part two of the three-way handshake */
626 info
->cstate
= PPTP_CALL_IN_REP
;
627 info
->pns_call_id
= ntohs(pptpReq
->icack
.callID
);
630 case PPTP_CALL_CLEAR_REQUEST
:
631 /* client requests hangup of call */
632 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
) {
633 DEBUGP("CLEAR_CALL but no session\n");
636 /* FUTURE: iterate over all calls and check if
637 * call ID is valid. We don't do this without newnat,
638 * because we only know about last call */
639 info
->cstate
= PPTP_CALL_CLEAR_REQ
;
641 case PPTP_SET_LINK_INFO
:
643 case PPTP_ECHO_REQUEST
:
644 case PPTP_ECHO_REPLY
:
645 /* I don't have to explain these ;) */
648 DEBUGP("invalid %s (TY=%d)\n", (msg
<= PPTP_MSG_MAX
)?
649 pptp_msg_name
[msg
]:pptp_msg_name
[0], msg
);
650 /* unknown: no need to create GRE masq table entry */
654 if (ip_nat_pptp_hook_outbound
)
655 return ip_nat_pptp_hook_outbound(pskb
, ct
, ctinfo
, ctlh
,
662 /* track caller id inside control connection, call expect_related */
664 conntrack_pptp_help(struct sk_buff
**pskb
,
665 struct ip_conntrack
*ct
, enum ip_conntrack_info ctinfo
)
668 struct pptp_pkt_hdr _pptph
, *pptph
;
669 struct tcphdr _tcph
, *tcph
;
670 u_int32_t tcplen
= (*pskb
)->len
- (*pskb
)->nh
.iph
->ihl
* 4;
672 int dir
= CTINFO2DIR(ctinfo
);
673 struct ip_ct_pptp_master
*info
= &ct
->help
.ct_pptp_info
;
674 unsigned int nexthdr_off
;
676 int oldsstate
, oldcstate
;
679 /* don't do any tracking before tcp handshake complete */
680 if (ctinfo
!= IP_CT_ESTABLISHED
681 && ctinfo
!= IP_CT_ESTABLISHED
+IP_CT_IS_REPLY
) {
682 DEBUGP("ctinfo = %u, skipping\n", ctinfo
);
686 nexthdr_off
= (*pskb
)->nh
.iph
->ihl
*4;
687 tcph
= skb_header_pointer(*pskb
, nexthdr_off
, sizeof(_tcph
), &_tcph
);
689 nexthdr_off
+= tcph
->doff
* 4;
690 datalen
= tcplen
- tcph
->doff
* 4;
692 if (tcph
->fin
|| tcph
->rst
) {
693 DEBUGP("RST/FIN received, timeouting GRE\n");
694 /* can't do this after real newnat */
695 info
->cstate
= PPTP_CALL_NONE
;
697 /* untrack this call id, unexpect GRE packets */
698 pptp_destroy_siblings(ct
);
701 pptph
= skb_header_pointer(*pskb
, nexthdr_off
, sizeof(_pptph
), &_pptph
);
703 DEBUGP("no full PPTP header, can't track\n");
706 nexthdr_off
+= sizeof(_pptph
);
707 datalen
-= sizeof(_pptph
);
709 /* if it's not a control message we can't do anything with it */
710 if (ntohs(pptph
->packetType
) != PPTP_PACKET_CONTROL
||
711 ntohl(pptph
->magicCookie
) != PPTP_MAGIC_COOKIE
) {
712 DEBUGP("not a control packet\n");
716 oldsstate
= info
->sstate
;
717 oldcstate
= info
->cstate
;
719 spin_lock_bh(&ip_pptp_lock
);
721 /* FIXME: We just blindly assume that the control connection is always
722 * established from PNS->PAC. However, RFC makes no guarantee */
723 if (dir
== IP_CT_DIR_ORIGINAL
)
724 /* client -> server (PNS -> PAC) */
725 ret
= pptp_outbound_pkt(pskb
, tcph
, nexthdr_off
, datalen
, ct
,
728 /* server -> client (PAC -> PNS) */
729 ret
= pptp_inbound_pkt(pskb
, tcph
, nexthdr_off
, datalen
, ct
,
731 DEBUGP("sstate: %d->%d, cstate: %d->%d\n",
732 oldsstate
, info
->sstate
, oldcstate
, info
->cstate
);
733 spin_unlock_bh(&ip_pptp_lock
);
738 /* control protocol helper */
739 static struct ip_conntrack_helper pptp
= {
740 .list
= { NULL
, NULL
},
745 .tuple
= { .src
= { .ip
= 0,
746 .u
= { .tcp
= { .port
=
747 __constant_htons(PPTP_CONTROL_PORT
) } }
751 .protonum
= IPPROTO_TCP
754 .mask
= { .src
= { .ip
= 0,
755 .u
= { .tcp
= { .port
= __constant_htons(0xffff) } }
762 .help
= conntrack_pptp_help
765 extern void ip_ct_proto_gre_fini(void);
766 extern int __init
ip_ct_proto_gre_init(void);
768 /* ip_conntrack_pptp initialization */
769 static int __init
ip_conntrack_helper_pptp_init(void)
773 retcode
= ip_ct_proto_gre_init();
777 DEBUGP(" registering helper\n");
778 if ((retcode
= ip_conntrack_helper_register(&pptp
))) {
779 printk(KERN_ERR
"Unable to register conntrack application "
780 "helper for pptp: %d\n", retcode
);
781 ip_ct_proto_gre_fini();
785 printk("ip_conntrack_pptp version %s loaded\n", IP_CT_PPTP_VERSION
);
789 static void __exit
ip_conntrack_helper_pptp_fini(void)
791 ip_conntrack_helper_unregister(&pptp
);
792 ip_ct_proto_gre_fini();
793 printk("ip_conntrack_pptp version %s unloaded\n", IP_CT_PPTP_VERSION
);
796 module_init(ip_conntrack_helper_pptp_init
);
797 module_exit(ip_conntrack_helper_pptp_fini
);
799 EXPORT_SYMBOL(ip_nat_pptp_hook_outbound
);
800 EXPORT_SYMBOL(ip_nat_pptp_hook_inbound
);
801 EXPORT_SYMBOL(ip_nat_pptp_hook_exp_gre
);
802 EXPORT_SYMBOL(ip_nat_pptp_hook_expectfn
);