2 * Connection tracking support for PPTP (Point to Point Tunneling Protocol).
3 * PPTP is a a protocol for creating virtual private networks.
4 * It is a specification defined by Microsoft and some vendors
5 * working with Microsoft. PPTP is built on top of a modified
6 * version of the Internet Generic Routing Encapsulation Protocol.
7 * GRE is defined in RFC 1701 and RFC 1702. Documentation of
8 * PPTP can be found in RFC 2637
10 * (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
12 * Development of this code funded by Astaro AG (http://www.astaro.com/)
14 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
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
22 * - testing of incoming PPTP calls
25 #include <linux/module.h>
26 #include <linux/skbuff.h>
28 #include <linux/tcp.h>
30 #include <net/netfilter/nf_conntrack.h>
31 #include <net/netfilter/nf_conntrack_core.h>
32 #include <net/netfilter/nf_conntrack_helper.h>
33 #include <net/netfilter/nf_conntrack_zones.h>
34 #include <linux/netfilter/nf_conntrack_proto_gre.h>
35 #include <linux/netfilter/nf_conntrack_pptp.h>
37 #define NF_CT_PPTP_VERSION "3.1"
39 MODULE_LICENSE("GPL");
40 MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
41 MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP");
42 MODULE_ALIAS("ip_conntrack_pptp");
43 MODULE_ALIAS_NFCT_HELPER("pptp");
45 static DEFINE_SPINLOCK(nf_pptp_lock
);
48 (*nf_nat_pptp_hook_outbound
)(struct sk_buff
*skb
,
49 struct nf_conn
*ct
, enum ip_conntrack_info ctinfo
,
50 unsigned int protoff
, struct PptpControlHeader
*ctlh
,
51 union pptp_ctrl_union
*pptpReq
) __read_mostly
;
52 EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_outbound
);
55 (*nf_nat_pptp_hook_inbound
)(struct sk_buff
*skb
,
56 struct nf_conn
*ct
, enum ip_conntrack_info ctinfo
,
57 unsigned int protoff
, struct PptpControlHeader
*ctlh
,
58 union pptp_ctrl_union
*pptpReq
) __read_mostly
;
59 EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_inbound
);
62 (*nf_nat_pptp_hook_exp_gre
)(struct nf_conntrack_expect
*expect_orig
,
63 struct nf_conntrack_expect
*expect_reply
)
65 EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_exp_gre
);
68 (*nf_nat_pptp_hook_expectfn
)(struct nf_conn
*ct
,
69 struct nf_conntrack_expect
*exp
) __read_mostly
;
70 EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_expectfn
);
72 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
73 /* PptpControlMessageType names */
74 const char *const pptp_msg_name
[] = {
76 "START_SESSION_REQUEST",
77 "START_SESSION_REPLY",
78 "STOP_SESSION_REQUEST",
88 "CALL_DISCONNECT_NOTIFY",
92 EXPORT_SYMBOL(pptp_msg_name
);
96 #define MINS * 60 SECS
97 #define HOURS * 60 MINS
99 #define PPTP_GRE_TIMEOUT (10 MINS)
100 #define PPTP_GRE_STREAM_TIMEOUT (5 HOURS)
102 static void pptp_expectfn(struct nf_conn
*ct
,
103 struct nf_conntrack_expect
*exp
)
105 struct net
*net
= nf_ct_net(ct
);
106 typeof(nf_nat_pptp_hook_expectfn
) nf_nat_pptp_expectfn
;
107 pr_debug("increasing timeouts\n");
109 /* increase timeout of GRE data channel conntrack entry */
110 ct
->proto
.gre
.timeout
= PPTP_GRE_TIMEOUT
;
111 ct
->proto
.gre
.stream_timeout
= PPTP_GRE_STREAM_TIMEOUT
;
113 /* Can you see how rusty this code is, compared with the pre-2.6.11
114 * one? That's what happened to my shiny newnat of 2002 ;( -HW */
117 nf_nat_pptp_expectfn
= rcu_dereference(nf_nat_pptp_hook_expectfn
);
118 if (nf_nat_pptp_expectfn
&& ct
->master
->status
& IPS_NAT_MASK
)
119 nf_nat_pptp_expectfn(ct
, exp
);
121 struct nf_conntrack_tuple inv_t
;
122 struct nf_conntrack_expect
*exp_other
;
124 /* obviously this tuple inversion only works until you do NAT */
125 nf_ct_invert_tuplepr(&inv_t
, &exp
->tuple
);
126 pr_debug("trying to unexpect other dir: ");
127 nf_ct_dump_tuple(&inv_t
);
129 exp_other
= nf_ct_expect_find_get(net
, nf_ct_zone(ct
), &inv_t
);
131 /* delete other expectation. */
133 nf_ct_unexpect_related(exp_other
);
134 nf_ct_expect_put(exp_other
);
136 pr_debug("not found\n");
142 static int destroy_sibling_or_exp(struct net
*net
, struct nf_conn
*ct
,
143 const struct nf_conntrack_tuple
*t
)
145 const struct nf_conntrack_tuple_hash
*h
;
146 const struct nf_conntrack_zone
*zone
;
147 struct nf_conntrack_expect
*exp
;
148 struct nf_conn
*sibling
;
150 pr_debug("trying to timeout ct or exp for tuple ");
153 zone
= nf_ct_zone(ct
);
154 h
= nf_conntrack_find_get(net
, zone
, t
);
156 sibling
= nf_ct_tuplehash_to_ctrack(h
);
157 pr_debug("setting timeout of conntrack %p to 0\n", sibling
);
158 sibling
->proto
.gre
.timeout
= 0;
159 sibling
->proto
.gre
.stream_timeout
= 0;
164 exp
= nf_ct_expect_find_get(net
, zone
, t
);
166 pr_debug("unexpect_related of expect %p\n", exp
);
167 nf_ct_unexpect_related(exp
);
168 nf_ct_expect_put(exp
);
175 /* timeout GRE data connections */
176 static void pptp_destroy_siblings(struct nf_conn
*ct
)
178 struct net
*net
= nf_ct_net(ct
);
179 const struct nf_ct_pptp_master
*ct_pptp_info
= nfct_help_data(ct
);
180 struct nf_conntrack_tuple t
;
182 nf_ct_gre_keymap_destroy(ct
);
184 /* try original (pns->pac) tuple */
185 memcpy(&t
, &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
, sizeof(t
));
186 t
.dst
.protonum
= IPPROTO_GRE
;
187 t
.src
.u
.gre
.key
= ct_pptp_info
->pns_call_id
;
188 t
.dst
.u
.gre
.key
= ct_pptp_info
->pac_call_id
;
189 if (!destroy_sibling_or_exp(net
, ct
, &t
))
190 pr_debug("failed to timeout original pns->pac ct/exp\n");
192 /* try reply (pac->pns) tuple */
193 memcpy(&t
, &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
, sizeof(t
));
194 t
.dst
.protonum
= IPPROTO_GRE
;
195 t
.src
.u
.gre
.key
= ct_pptp_info
->pac_call_id
;
196 t
.dst
.u
.gre
.key
= ct_pptp_info
->pns_call_id
;
197 if (!destroy_sibling_or_exp(net
, ct
, &t
))
198 pr_debug("failed to timeout reply pac->pns ct/exp\n");
201 /* expect GRE connections (PNS->PAC and PAC->PNS direction) */
202 static int exp_gre(struct nf_conn
*ct
, __be16 callid
, __be16 peer_callid
)
204 struct nf_conntrack_expect
*exp_orig
, *exp_reply
;
205 enum ip_conntrack_dir dir
;
207 typeof(nf_nat_pptp_hook_exp_gre
) nf_nat_pptp_exp_gre
;
209 exp_orig
= nf_ct_expect_alloc(ct
);
210 if (exp_orig
== NULL
)
213 exp_reply
= nf_ct_expect_alloc(ct
);
214 if (exp_reply
== NULL
)
217 /* original direction, PNS->PAC */
218 dir
= IP_CT_DIR_ORIGINAL
;
219 nf_ct_expect_init(exp_orig
, NF_CT_EXPECT_CLASS_DEFAULT
,
221 &ct
->tuplehash
[dir
].tuple
.src
.u3
,
222 &ct
->tuplehash
[dir
].tuple
.dst
.u3
,
223 IPPROTO_GRE
, &peer_callid
, &callid
);
224 exp_orig
->expectfn
= pptp_expectfn
;
226 /* reply direction, PAC->PNS */
227 dir
= IP_CT_DIR_REPLY
;
228 nf_ct_expect_init(exp_reply
, NF_CT_EXPECT_CLASS_DEFAULT
,
230 &ct
->tuplehash
[dir
].tuple
.src
.u3
,
231 &ct
->tuplehash
[dir
].tuple
.dst
.u3
,
232 IPPROTO_GRE
, &callid
, &peer_callid
);
233 exp_reply
->expectfn
= pptp_expectfn
;
235 nf_nat_pptp_exp_gre
= rcu_dereference(nf_nat_pptp_hook_exp_gre
);
236 if (nf_nat_pptp_exp_gre
&& ct
->status
& IPS_NAT_MASK
)
237 nf_nat_pptp_exp_gre(exp_orig
, exp_reply
);
238 if (nf_ct_expect_related(exp_orig
) != 0)
240 if (nf_ct_expect_related(exp_reply
) != 0)
241 goto out_unexpect_orig
;
243 /* Add GRE keymap entries */
244 if (nf_ct_gre_keymap_add(ct
, IP_CT_DIR_ORIGINAL
, &exp_orig
->tuple
) != 0)
245 goto out_unexpect_both
;
246 if (nf_ct_gre_keymap_add(ct
, IP_CT_DIR_REPLY
, &exp_reply
->tuple
) != 0) {
247 nf_ct_gre_keymap_destroy(ct
);
248 goto out_unexpect_both
;
253 nf_ct_expect_put(exp_reply
);
255 nf_ct_expect_put(exp_orig
);
260 nf_ct_unexpect_related(exp_reply
);
262 nf_ct_unexpect_related(exp_orig
);
267 pptp_inbound_pkt(struct sk_buff
*skb
, unsigned int protoff
,
268 struct PptpControlHeader
*ctlh
,
269 union pptp_ctrl_union
*pptpReq
,
272 enum ip_conntrack_info ctinfo
)
274 struct nf_ct_pptp_master
*info
= nfct_help_data(ct
);
276 __be16 cid
= 0, pcid
= 0;
277 typeof(nf_nat_pptp_hook_inbound
) nf_nat_pptp_inbound
;
279 msg
= ntohs(ctlh
->messageType
);
280 pr_debug("inbound control message %s\n", pptp_msg_name
[msg
]);
283 case PPTP_START_SESSION_REPLY
:
284 /* server confirms new control session */
285 if (info
->sstate
< PPTP_SESSION_REQUESTED
)
287 if (pptpReq
->srep
.resultCode
== PPTP_START_OK
)
288 info
->sstate
= PPTP_SESSION_CONFIRMED
;
290 info
->sstate
= PPTP_SESSION_ERROR
;
293 case PPTP_STOP_SESSION_REPLY
:
294 /* server confirms end of control session */
295 if (info
->sstate
> PPTP_SESSION_STOPREQ
)
297 if (pptpReq
->strep
.resultCode
== PPTP_STOP_OK
)
298 info
->sstate
= PPTP_SESSION_NONE
;
300 info
->sstate
= PPTP_SESSION_ERROR
;
303 case PPTP_OUT_CALL_REPLY
:
304 /* server accepted call, we now expect GRE frames */
305 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
)
307 if (info
->cstate
!= PPTP_CALL_OUT_REQ
&&
308 info
->cstate
!= PPTP_CALL_OUT_CONF
)
311 cid
= pptpReq
->ocack
.callID
;
312 pcid
= pptpReq
->ocack
.peersCallID
;
313 if (info
->pns_call_id
!= pcid
)
315 pr_debug("%s, CID=%X, PCID=%X\n", pptp_msg_name
[msg
],
316 ntohs(cid
), ntohs(pcid
));
318 if (pptpReq
->ocack
.resultCode
== PPTP_OUTCALL_CONNECT
) {
319 info
->cstate
= PPTP_CALL_OUT_CONF
;
320 info
->pac_call_id
= cid
;
321 exp_gre(ct
, cid
, pcid
);
323 info
->cstate
= PPTP_CALL_NONE
;
326 case PPTP_IN_CALL_REQUEST
:
327 /* server tells us about incoming call request */
328 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
)
331 cid
= pptpReq
->icreq
.callID
;
332 pr_debug("%s, CID=%X\n", pptp_msg_name
[msg
], ntohs(cid
));
333 info
->cstate
= PPTP_CALL_IN_REQ
;
334 info
->pac_call_id
= cid
;
337 case PPTP_IN_CALL_CONNECT
:
338 /* server tells us about incoming call established */
339 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
)
341 if (info
->cstate
!= PPTP_CALL_IN_REP
&&
342 info
->cstate
!= PPTP_CALL_IN_CONF
)
345 pcid
= pptpReq
->iccon
.peersCallID
;
346 cid
= info
->pac_call_id
;
348 if (info
->pns_call_id
!= pcid
)
351 pr_debug("%s, PCID=%X\n", pptp_msg_name
[msg
], ntohs(pcid
));
352 info
->cstate
= PPTP_CALL_IN_CONF
;
354 /* we expect a GRE connection from PAC to PNS */
355 exp_gre(ct
, cid
, pcid
);
358 case PPTP_CALL_DISCONNECT_NOTIFY
:
359 /* server confirms disconnect */
360 cid
= pptpReq
->disc
.callID
;
361 pr_debug("%s, CID=%X\n", pptp_msg_name
[msg
], ntohs(cid
));
362 info
->cstate
= PPTP_CALL_NONE
;
364 /* untrack this call id, unexpect GRE packets */
365 pptp_destroy_siblings(ct
);
368 case PPTP_WAN_ERROR_NOTIFY
:
369 case PPTP_SET_LINK_INFO
:
370 case PPTP_ECHO_REQUEST
:
371 case PPTP_ECHO_REPLY
:
372 /* I don't have to explain these ;) */
379 nf_nat_pptp_inbound
= rcu_dereference(nf_nat_pptp_hook_inbound
);
380 if (nf_nat_pptp_inbound
&& ct
->status
& IPS_NAT_MASK
)
381 return nf_nat_pptp_inbound(skb
, ct
, ctinfo
,
382 protoff
, ctlh
, pptpReq
);
386 pr_debug("invalid %s: type=%d cid=%u pcid=%u "
387 "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
388 msg
<= PPTP_MSG_MAX
? pptp_msg_name
[msg
] : pptp_msg_name
[0],
389 msg
, ntohs(cid
), ntohs(pcid
), info
->cstate
, info
->sstate
,
390 ntohs(info
->pns_call_id
), ntohs(info
->pac_call_id
));
395 pptp_outbound_pkt(struct sk_buff
*skb
, unsigned int protoff
,
396 struct PptpControlHeader
*ctlh
,
397 union pptp_ctrl_union
*pptpReq
,
400 enum ip_conntrack_info ctinfo
)
402 struct nf_ct_pptp_master
*info
= nfct_help_data(ct
);
404 __be16 cid
= 0, pcid
= 0;
405 typeof(nf_nat_pptp_hook_outbound
) nf_nat_pptp_outbound
;
407 msg
= ntohs(ctlh
->messageType
);
408 pr_debug("outbound control message %s\n", pptp_msg_name
[msg
]);
411 case PPTP_START_SESSION_REQUEST
:
412 /* client requests for new control session */
413 if (info
->sstate
!= PPTP_SESSION_NONE
)
415 info
->sstate
= PPTP_SESSION_REQUESTED
;
418 case PPTP_STOP_SESSION_REQUEST
:
419 /* client requests end of control session */
420 info
->sstate
= PPTP_SESSION_STOPREQ
;
423 case PPTP_OUT_CALL_REQUEST
:
424 /* client initiating connection to server */
425 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
)
427 info
->cstate
= PPTP_CALL_OUT_REQ
;
428 /* track PNS call id */
429 cid
= pptpReq
->ocreq
.callID
;
430 pr_debug("%s, CID=%X\n", pptp_msg_name
[msg
], ntohs(cid
));
431 info
->pns_call_id
= cid
;
434 case PPTP_IN_CALL_REPLY
:
435 /* client answers incoming call */
436 if (info
->cstate
!= PPTP_CALL_IN_REQ
&&
437 info
->cstate
!= PPTP_CALL_IN_REP
)
440 cid
= pptpReq
->icack
.callID
;
441 pcid
= pptpReq
->icack
.peersCallID
;
442 if (info
->pac_call_id
!= pcid
)
444 pr_debug("%s, CID=%X PCID=%X\n", pptp_msg_name
[msg
],
445 ntohs(cid
), ntohs(pcid
));
447 if (pptpReq
->icack
.resultCode
== PPTP_INCALL_ACCEPT
) {
448 /* part two of the three-way handshake */
449 info
->cstate
= PPTP_CALL_IN_REP
;
450 info
->pns_call_id
= cid
;
452 info
->cstate
= PPTP_CALL_NONE
;
455 case PPTP_CALL_CLEAR_REQUEST
:
456 /* client requests hangup of call */
457 if (info
->sstate
!= PPTP_SESSION_CONFIRMED
)
459 /* FUTURE: iterate over all calls and check if
460 * call ID is valid. We don't do this without newnat,
461 * because we only know about last call */
462 info
->cstate
= PPTP_CALL_CLEAR_REQ
;
465 case PPTP_SET_LINK_INFO
:
466 case PPTP_ECHO_REQUEST
:
467 case PPTP_ECHO_REPLY
:
468 /* I don't have to explain these ;) */
475 nf_nat_pptp_outbound
= rcu_dereference(nf_nat_pptp_hook_outbound
);
476 if (nf_nat_pptp_outbound
&& ct
->status
& IPS_NAT_MASK
)
477 return nf_nat_pptp_outbound(skb
, ct
, ctinfo
,
478 protoff
, ctlh
, pptpReq
);
482 pr_debug("invalid %s: type=%d cid=%u pcid=%u "
483 "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
484 msg
<= PPTP_MSG_MAX
? pptp_msg_name
[msg
] : pptp_msg_name
[0],
485 msg
, ntohs(cid
), ntohs(pcid
), info
->cstate
, info
->sstate
,
486 ntohs(info
->pns_call_id
), ntohs(info
->pac_call_id
));
490 static const unsigned int pptp_msg_size
[] = {
491 [PPTP_START_SESSION_REQUEST
] = sizeof(struct PptpStartSessionRequest
),
492 [PPTP_START_SESSION_REPLY
] = sizeof(struct PptpStartSessionReply
),
493 [PPTP_STOP_SESSION_REQUEST
] = sizeof(struct PptpStopSessionRequest
),
494 [PPTP_STOP_SESSION_REPLY
] = sizeof(struct PptpStopSessionReply
),
495 [PPTP_OUT_CALL_REQUEST
] = sizeof(struct PptpOutCallRequest
),
496 [PPTP_OUT_CALL_REPLY
] = sizeof(struct PptpOutCallReply
),
497 [PPTP_IN_CALL_REQUEST
] = sizeof(struct PptpInCallRequest
),
498 [PPTP_IN_CALL_REPLY
] = sizeof(struct PptpInCallReply
),
499 [PPTP_IN_CALL_CONNECT
] = sizeof(struct PptpInCallConnected
),
500 [PPTP_CALL_CLEAR_REQUEST
] = sizeof(struct PptpClearCallRequest
),
501 [PPTP_CALL_DISCONNECT_NOTIFY
] = sizeof(struct PptpCallDisconnectNotify
),
502 [PPTP_WAN_ERROR_NOTIFY
] = sizeof(struct PptpWanErrorNotify
),
503 [PPTP_SET_LINK_INFO
] = sizeof(struct PptpSetLinkInfo
),
506 /* track caller id inside control connection, call expect_related */
508 conntrack_pptp_help(struct sk_buff
*skb
, unsigned int protoff
,
509 struct nf_conn
*ct
, enum ip_conntrack_info ctinfo
)
512 int dir
= CTINFO2DIR(ctinfo
);
513 const struct nf_ct_pptp_master
*info
= nfct_help_data(ct
);
514 const struct tcphdr
*tcph
;
516 const struct pptp_pkt_hdr
*pptph
;
517 struct pptp_pkt_hdr _pptph
;
518 struct PptpControlHeader _ctlh
, *ctlh
;
519 union pptp_ctrl_union _pptpReq
, *pptpReq
;
520 unsigned int tcplen
= skb
->len
- protoff
;
521 unsigned int datalen
, reqlen
, nexthdr_off
;
522 int oldsstate
, oldcstate
;
526 /* don't do any tracking before tcp handshake complete */
527 if (ctinfo
!= IP_CT_ESTABLISHED
&& ctinfo
!= IP_CT_ESTABLISHED_REPLY
)
530 nexthdr_off
= protoff
;
531 tcph
= skb_header_pointer(skb
, nexthdr_off
, sizeof(_tcph
), &_tcph
);
533 nexthdr_off
+= tcph
->doff
* 4;
534 datalen
= tcplen
- tcph
->doff
* 4;
536 pptph
= skb_header_pointer(skb
, nexthdr_off
, sizeof(_pptph
), &_pptph
);
538 pr_debug("no full PPTP header, can't track\n");
541 nexthdr_off
+= sizeof(_pptph
);
542 datalen
-= sizeof(_pptph
);
544 /* if it's not a control message we can't do anything with it */
545 if (ntohs(pptph
->packetType
) != PPTP_PACKET_CONTROL
||
546 ntohl(pptph
->magicCookie
) != PPTP_MAGIC_COOKIE
) {
547 pr_debug("not a control packet\n");
551 ctlh
= skb_header_pointer(skb
, nexthdr_off
, sizeof(_ctlh
), &_ctlh
);
554 nexthdr_off
+= sizeof(_ctlh
);
555 datalen
-= sizeof(_ctlh
);
558 msg
= ntohs(ctlh
->messageType
);
559 if (msg
> 0 && msg
<= PPTP_MSG_MAX
&& reqlen
< pptp_msg_size
[msg
])
561 if (reqlen
> sizeof(*pptpReq
))
562 reqlen
= sizeof(*pptpReq
);
564 pptpReq
= skb_header_pointer(skb
, nexthdr_off
, reqlen
, &_pptpReq
);
568 oldsstate
= info
->sstate
;
569 oldcstate
= info
->cstate
;
571 spin_lock_bh(&nf_pptp_lock
);
573 /* FIXME: We just blindly assume that the control connection is always
574 * established from PNS->PAC. However, RFC makes no guarantee */
575 if (dir
== IP_CT_DIR_ORIGINAL
)
576 /* client -> server (PNS -> PAC) */
577 ret
= pptp_outbound_pkt(skb
, protoff
, ctlh
, pptpReq
, reqlen
, ct
,
580 /* server -> client (PAC -> PNS) */
581 ret
= pptp_inbound_pkt(skb
, protoff
, ctlh
, pptpReq
, reqlen
, ct
,
583 pr_debug("sstate: %d->%d, cstate: %d->%d\n",
584 oldsstate
, info
->sstate
, oldcstate
, info
->cstate
);
585 spin_unlock_bh(&nf_pptp_lock
);
590 static const struct nf_conntrack_expect_policy pptp_exp_policy
= {
595 /* control protocol helper */
596 static struct nf_conntrack_helper pptp __read_mostly
= {
599 .data_len
= sizeof(struct nf_ct_pptp_master
),
600 .tuple
.src
.l3num
= AF_INET
,
601 .tuple
.src
.u
.tcp
.port
= cpu_to_be16(PPTP_CONTROL_PORT
),
602 .tuple
.dst
.protonum
= IPPROTO_TCP
,
603 .help
= conntrack_pptp_help
,
604 .destroy
= pptp_destroy_siblings
,
605 .expect_policy
= &pptp_exp_policy
,
608 static int __init
nf_conntrack_pptp_init(void)
610 return nf_conntrack_helper_register(&pptp
);
613 static void __exit
nf_conntrack_pptp_fini(void)
615 nf_conntrack_helper_unregister(&pptp
);
618 module_init(nf_conntrack_pptp_init
);
619 module_exit(nf_conntrack_pptp_fini
);