1 // SPDX-License-Identifier: GPL-2.0-only
3 * Connection tracking support for PPTP (Point to Point Tunneling Protocol).
4 * PPTP is a protocol for creating virtual private networks.
5 * It is a specification defined by Microsoft and some vendors
6 * working with Microsoft. PPTP is built on top of a modified
7 * version of the Internet Generic Routing Encapsulation Protocol.
8 * GRE is defined in RFC 1701 and RFC 1702. Documentation of
9 * PPTP can be found in RFC 2637
11 * (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
13 * Development of this code funded by Astaro AG (http://www.astaro.com/)
15 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
18 * - We blindly assume that control connections are always
19 * established in PNS->PAC direction. This is a violation
21 * - We can only support one single call within each session
23 * - testing of incoming PPTP calls
26 #include <linux/module.h>
27 #include <linux/skbuff.h>
29 #include <linux/tcp.h>
31 #include <net/netfilter/nf_conntrack.h>
32 #include <net/netfilter/nf_conntrack_core.h>
33 #include <net/netfilter/nf_conntrack_helper.h>
34 #include <net/netfilter/nf_conntrack_zones.h>
35 #include <linux/netfilter/nf_conntrack_proto_gre.h>
36 #include <linux/netfilter/nf_conntrack_pptp.h>
38 #define NF_CT_PPTP_VERSION "3.1"
40 MODULE_LICENSE("GPL");
41 MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
42 MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP");
43 MODULE_ALIAS("ip_conntrack_pptp");
44 MODULE_ALIAS_NFCT_HELPER("pptp");
46 static DEFINE_SPINLOCK(nf_pptp_lock);
49 (*nf_nat_pptp_hook_outbound)(struct sk_buff *skb,
50 struct nf_conn *ct, enum ip_conntrack_info ctinfo,
51 unsigned int protoff, struct PptpControlHeader *ctlh,
52 union pptp_ctrl_union *pptpReq) __read_mostly;
53 EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_outbound);
56 (*nf_nat_pptp_hook_inbound)(struct sk_buff *skb,
57 struct nf_conn *ct, enum ip_conntrack_info ctinfo,
58 unsigned int protoff, struct PptpControlHeader *ctlh,
59 union pptp_ctrl_union *pptpReq) __read_mostly;
60 EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_inbound);
63 (*nf_nat_pptp_hook_exp_gre)(struct nf_conntrack_expect *expect_orig,
64 struct nf_conntrack_expect *expect_reply)
66 EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_exp_gre);
69 (*nf_nat_pptp_hook_expectfn)(struct nf_conn *ct,
70 struct nf_conntrack_expect *exp) __read_mostly;
71 EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_expectfn);
73 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
74 /* PptpControlMessageType names */
75 static const char *const pptp_msg_name_array[PPTP_MSG_MAX + 1] = {
76 [0] = "UNKNOWN_MESSAGE",
77 [PPTP_START_SESSION_REQUEST] = "START_SESSION_REQUEST",
78 [PPTP_START_SESSION_REPLY] = "START_SESSION_REPLY",
79 [PPTP_STOP_SESSION_REQUEST] = "STOP_SESSION_REQUEST",
80 [PPTP_STOP_SESSION_REPLY] = "STOP_SESSION_REPLY",
81 [PPTP_ECHO_REQUEST] = "ECHO_REQUEST",
82 [PPTP_ECHO_REPLY] = "ECHO_REPLY",
83 [PPTP_OUT_CALL_REQUEST] = "OUT_CALL_REQUEST",
84 [PPTP_OUT_CALL_REPLY] = "OUT_CALL_REPLY",
85 [PPTP_IN_CALL_REQUEST] = "IN_CALL_REQUEST",
86 [PPTP_IN_CALL_REPLY] = "IN_CALL_REPLY",
87 [PPTP_IN_CALL_CONNECT] = "IN_CALL_CONNECT",
88 [PPTP_CALL_CLEAR_REQUEST] = "CALL_CLEAR_REQUEST",
89 [PPTP_CALL_DISCONNECT_NOTIFY] = "CALL_DISCONNECT_NOTIFY",
90 [PPTP_WAN_ERROR_NOTIFY] = "WAN_ERROR_NOTIFY",
91 [PPTP_SET_LINK_INFO] = "SET_LINK_INFO"
94 const char *pptp_msg_name(u_int16_t msg)
96 if (msg > PPTP_MSG_MAX)
97 return pptp_msg_name_array[0];
99 return pptp_msg_name_array[msg];
101 EXPORT_SYMBOL(pptp_msg_name);
105 #define MINS * 60 SECS
106 #define HOURS * 60 MINS
108 #define PPTP_GRE_TIMEOUT (10 MINS)
109 #define PPTP_GRE_STREAM_TIMEOUT (5 HOURS)
111 static void pptp_expectfn(struct nf_conn *ct,
112 struct nf_conntrack_expect *exp)
114 struct net *net = nf_ct_net(ct);
115 typeof(nf_nat_pptp_hook_expectfn) nf_nat_pptp_expectfn;
116 pr_debug("increasing timeouts\n");
118 /* increase timeout of GRE data channel conntrack entry */
119 ct->proto.gre.timeout = PPTP_GRE_TIMEOUT;
120 ct->proto.gre.stream_timeout = PPTP_GRE_STREAM_TIMEOUT;
122 /* Can you see how rusty this code is, compared with the pre-2.6.11
123 * one? That's what happened to my shiny newnat of 2002 ;( -HW */
125 nf_nat_pptp_expectfn = rcu_dereference(nf_nat_pptp_hook_expectfn);
126 if (nf_nat_pptp_expectfn && ct->master->status & IPS_NAT_MASK)
127 nf_nat_pptp_expectfn(ct, exp);
129 struct nf_conntrack_tuple inv_t;
130 struct nf_conntrack_expect *exp_other;
132 /* obviously this tuple inversion only works until you do NAT */
133 nf_ct_invert_tuple(&inv_t, &exp->tuple);
134 pr_debug("trying to unexpect other dir: ");
135 nf_ct_dump_tuple(&inv_t);
137 exp_other = nf_ct_expect_find_get(net, nf_ct_zone(ct), &inv_t);
139 /* delete other expectation. */
141 nf_ct_unexpect_related(exp_other);
142 nf_ct_expect_put(exp_other);
144 pr_debug("not found\n");
149 static int destroy_sibling_or_exp(struct net *net, struct nf_conn *ct,
150 const struct nf_conntrack_tuple *t)
152 const struct nf_conntrack_tuple_hash *h;
153 const struct nf_conntrack_zone *zone;
154 struct nf_conntrack_expect *exp;
155 struct nf_conn *sibling;
157 pr_debug("trying to timeout ct or exp for tuple ");
160 zone = nf_ct_zone(ct);
161 h = nf_conntrack_find_get(net, zone, t);
163 sibling = nf_ct_tuplehash_to_ctrack(h);
164 pr_debug("setting timeout of conntrack %p to 0\n", sibling);
165 sibling->proto.gre.timeout = 0;
166 sibling->proto.gre.stream_timeout = 0;
171 exp = nf_ct_expect_find_get(net, zone, t);
173 pr_debug("unexpect_related of expect %p\n", exp);
174 nf_ct_unexpect_related(exp);
175 nf_ct_expect_put(exp);
182 /* timeout GRE data connections */
183 static void pptp_destroy_siblings(struct nf_conn *ct)
185 struct net *net = nf_ct_net(ct);
186 const struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
187 struct nf_conntrack_tuple t;
189 nf_ct_gre_keymap_destroy(ct);
191 /* try original (pns->pac) tuple */
192 memcpy(&t, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(t));
193 t.dst.protonum = IPPROTO_GRE;
194 t.src.u.gre.key = ct_pptp_info->pns_call_id;
195 t.dst.u.gre.key = ct_pptp_info->pac_call_id;
196 if (!destroy_sibling_or_exp(net, ct, &t))
197 pr_debug("failed to timeout original pns->pac ct/exp\n");
199 /* try reply (pac->pns) tuple */
200 memcpy(&t, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, sizeof(t));
201 t.dst.protonum = IPPROTO_GRE;
202 t.src.u.gre.key = ct_pptp_info->pac_call_id;
203 t.dst.u.gre.key = ct_pptp_info->pns_call_id;
204 if (!destroy_sibling_or_exp(net, ct, &t))
205 pr_debug("failed to timeout reply pac->pns ct/exp\n");
208 /* expect GRE connections (PNS->PAC and PAC->PNS direction) */
209 static int exp_gre(struct nf_conn *ct, __be16 callid, __be16 peer_callid)
211 struct nf_conntrack_expect *exp_orig, *exp_reply;
212 enum ip_conntrack_dir dir;
214 typeof(nf_nat_pptp_hook_exp_gre) nf_nat_pptp_exp_gre;
216 exp_orig = nf_ct_expect_alloc(ct);
217 if (exp_orig == NULL)
220 exp_reply = nf_ct_expect_alloc(ct);
221 if (exp_reply == NULL)
224 /* original direction, PNS->PAC */
225 dir = IP_CT_DIR_ORIGINAL;
226 nf_ct_expect_init(exp_orig, NF_CT_EXPECT_CLASS_DEFAULT,
228 &ct->tuplehash[dir].tuple.src.u3,
229 &ct->tuplehash[dir].tuple.dst.u3,
230 IPPROTO_GRE, &peer_callid, &callid);
231 exp_orig->expectfn = pptp_expectfn;
233 /* reply direction, PAC->PNS */
234 dir = IP_CT_DIR_REPLY;
235 nf_ct_expect_init(exp_reply, NF_CT_EXPECT_CLASS_DEFAULT,
237 &ct->tuplehash[dir].tuple.src.u3,
238 &ct->tuplehash[dir].tuple.dst.u3,
239 IPPROTO_GRE, &callid, &peer_callid);
240 exp_reply->expectfn = pptp_expectfn;
242 nf_nat_pptp_exp_gre = rcu_dereference(nf_nat_pptp_hook_exp_gre);
243 if (nf_nat_pptp_exp_gre && ct->status & IPS_NAT_MASK)
244 nf_nat_pptp_exp_gre(exp_orig, exp_reply);
245 if (nf_ct_expect_related(exp_orig, 0) != 0)
247 if (nf_ct_expect_related(exp_reply, 0) != 0)
248 goto out_unexpect_orig;
250 /* Add GRE keymap entries */
251 if (nf_ct_gre_keymap_add(ct, IP_CT_DIR_ORIGINAL, &exp_orig->tuple) != 0)
252 goto out_unexpect_both;
253 if (nf_ct_gre_keymap_add(ct, IP_CT_DIR_REPLY, &exp_reply->tuple) != 0) {
254 nf_ct_gre_keymap_destroy(ct);
255 goto out_unexpect_both;
260 nf_ct_expect_put(exp_reply);
262 nf_ct_expect_put(exp_orig);
267 nf_ct_unexpect_related(exp_reply);
269 nf_ct_unexpect_related(exp_orig);
274 pptp_inbound_pkt(struct sk_buff *skb, unsigned int protoff,
275 struct PptpControlHeader *ctlh,
276 union pptp_ctrl_union *pptpReq,
279 enum ip_conntrack_info ctinfo)
281 struct nf_ct_pptp_master *info = nfct_help_data(ct);
283 __be16 cid = 0, pcid = 0;
284 typeof(nf_nat_pptp_hook_inbound) nf_nat_pptp_inbound;
286 msg = ntohs(ctlh->messageType);
287 pr_debug("inbound control message %s\n", pptp_msg_name(msg));
290 case PPTP_START_SESSION_REPLY:
291 /* server confirms new control session */
292 if (info->sstate < PPTP_SESSION_REQUESTED)
294 if (pptpReq->srep.resultCode == PPTP_START_OK)
295 info->sstate = PPTP_SESSION_CONFIRMED;
297 info->sstate = PPTP_SESSION_ERROR;
300 case PPTP_STOP_SESSION_REPLY:
301 /* server confirms end of control session */
302 if (info->sstate > PPTP_SESSION_STOPREQ)
304 if (pptpReq->strep.resultCode == PPTP_STOP_OK)
305 info->sstate = PPTP_SESSION_NONE;
307 info->sstate = PPTP_SESSION_ERROR;
310 case PPTP_OUT_CALL_REPLY:
311 /* server accepted call, we now expect GRE frames */
312 if (info->sstate != PPTP_SESSION_CONFIRMED)
314 if (info->cstate != PPTP_CALL_OUT_REQ &&
315 info->cstate != PPTP_CALL_OUT_CONF)
318 cid = pptpReq->ocack.callID;
319 pcid = pptpReq->ocack.peersCallID;
320 if (info->pns_call_id != pcid)
322 pr_debug("%s, CID=%X, PCID=%X\n", pptp_msg_name(msg),
323 ntohs(cid), ntohs(pcid));
325 if (pptpReq->ocack.resultCode == PPTP_OUTCALL_CONNECT) {
326 info->cstate = PPTP_CALL_OUT_CONF;
327 info->pac_call_id = cid;
328 exp_gre(ct, cid, pcid);
330 info->cstate = PPTP_CALL_NONE;
333 case PPTP_IN_CALL_REQUEST:
334 /* server tells us about incoming call request */
335 if (info->sstate != PPTP_SESSION_CONFIRMED)
338 cid = pptpReq->icreq.callID;
339 pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
340 info->cstate = PPTP_CALL_IN_REQ;
341 info->pac_call_id = cid;
344 case PPTP_IN_CALL_CONNECT:
345 /* server tells us about incoming call established */
346 if (info->sstate != PPTP_SESSION_CONFIRMED)
348 if (info->cstate != PPTP_CALL_IN_REP &&
349 info->cstate != PPTP_CALL_IN_CONF)
352 pcid = pptpReq->iccon.peersCallID;
353 cid = info->pac_call_id;
355 if (info->pns_call_id != pcid)
358 pr_debug("%s, PCID=%X\n", pptp_msg_name(msg), ntohs(pcid));
359 info->cstate = PPTP_CALL_IN_CONF;
361 /* we expect a GRE connection from PAC to PNS */
362 exp_gre(ct, cid, pcid);
365 case PPTP_CALL_DISCONNECT_NOTIFY:
366 /* server confirms disconnect */
367 cid = pptpReq->disc.callID;
368 pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
369 info->cstate = PPTP_CALL_NONE;
371 /* untrack this call id, unexpect GRE packets */
372 pptp_destroy_siblings(ct);
375 case PPTP_WAN_ERROR_NOTIFY:
376 case PPTP_SET_LINK_INFO:
377 case PPTP_ECHO_REQUEST:
378 case PPTP_ECHO_REPLY:
379 /* I don't have to explain these ;) */
386 nf_nat_pptp_inbound = rcu_dereference(nf_nat_pptp_hook_inbound);
387 if (nf_nat_pptp_inbound && ct->status & IPS_NAT_MASK)
388 return nf_nat_pptp_inbound(skb, ct, ctinfo,
389 protoff, ctlh, pptpReq);
393 pr_debug("invalid %s: type=%d cid=%u pcid=%u "
394 "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
396 msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
397 ntohs(info->pns_call_id), ntohs(info->pac_call_id));
402 pptp_outbound_pkt(struct sk_buff *skb, unsigned int protoff,
403 struct PptpControlHeader *ctlh,
404 union pptp_ctrl_union *pptpReq,
407 enum ip_conntrack_info ctinfo)
409 struct nf_ct_pptp_master *info = nfct_help_data(ct);
411 __be16 cid = 0, pcid = 0;
412 typeof(nf_nat_pptp_hook_outbound) nf_nat_pptp_outbound;
414 msg = ntohs(ctlh->messageType);
415 pr_debug("outbound control message %s\n", pptp_msg_name(msg));
418 case PPTP_START_SESSION_REQUEST:
419 /* client requests for new control session */
420 if (info->sstate != PPTP_SESSION_NONE)
422 info->sstate = PPTP_SESSION_REQUESTED;
425 case PPTP_STOP_SESSION_REQUEST:
426 /* client requests end of control session */
427 info->sstate = PPTP_SESSION_STOPREQ;
430 case PPTP_OUT_CALL_REQUEST:
431 /* client initiating connection to server */
432 if (info->sstate != PPTP_SESSION_CONFIRMED)
434 info->cstate = PPTP_CALL_OUT_REQ;
435 /* track PNS call id */
436 cid = pptpReq->ocreq.callID;
437 pr_debug("%s, CID=%X\n", pptp_msg_name(msg), ntohs(cid));
438 info->pns_call_id = cid;
441 case PPTP_IN_CALL_REPLY:
442 /* client answers incoming call */
443 if (info->cstate != PPTP_CALL_IN_REQ &&
444 info->cstate != PPTP_CALL_IN_REP)
447 cid = pptpReq->icack.callID;
448 pcid = pptpReq->icack.peersCallID;
449 if (info->pac_call_id != pcid)
451 pr_debug("%s, CID=%X PCID=%X\n", pptp_msg_name(msg),
452 ntohs(cid), ntohs(pcid));
454 if (pptpReq->icack.resultCode == PPTP_INCALL_ACCEPT) {
455 /* part two of the three-way handshake */
456 info->cstate = PPTP_CALL_IN_REP;
457 info->pns_call_id = cid;
459 info->cstate = PPTP_CALL_NONE;
462 case PPTP_CALL_CLEAR_REQUEST:
463 /* client requests hangup of call */
464 if (info->sstate != PPTP_SESSION_CONFIRMED)
466 /* FUTURE: iterate over all calls and check if
467 * call ID is valid. We don't do this without newnat,
468 * because we only know about last call */
469 info->cstate = PPTP_CALL_CLEAR_REQ;
472 case PPTP_SET_LINK_INFO:
473 case PPTP_ECHO_REQUEST:
474 case PPTP_ECHO_REPLY:
475 /* I don't have to explain these ;) */
482 nf_nat_pptp_outbound = rcu_dereference(nf_nat_pptp_hook_outbound);
483 if (nf_nat_pptp_outbound && ct->status & IPS_NAT_MASK)
484 return nf_nat_pptp_outbound(skb, ct, ctinfo,
485 protoff, ctlh, pptpReq);
489 pr_debug("invalid %s: type=%d cid=%u pcid=%u "
490 "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
492 msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
493 ntohs(info->pns_call_id), ntohs(info->pac_call_id));
497 static const unsigned int pptp_msg_size[] = {
498 [PPTP_START_SESSION_REQUEST] = sizeof(struct PptpStartSessionRequest),
499 [PPTP_START_SESSION_REPLY] = sizeof(struct PptpStartSessionReply),
500 [PPTP_STOP_SESSION_REQUEST] = sizeof(struct PptpStopSessionRequest),
501 [PPTP_STOP_SESSION_REPLY] = sizeof(struct PptpStopSessionReply),
502 [PPTP_OUT_CALL_REQUEST] = sizeof(struct PptpOutCallRequest),
503 [PPTP_OUT_CALL_REPLY] = sizeof(struct PptpOutCallReply),
504 [PPTP_IN_CALL_REQUEST] = sizeof(struct PptpInCallRequest),
505 [PPTP_IN_CALL_REPLY] = sizeof(struct PptpInCallReply),
506 [PPTP_IN_CALL_CONNECT] = sizeof(struct PptpInCallConnected),
507 [PPTP_CALL_CLEAR_REQUEST] = sizeof(struct PptpClearCallRequest),
508 [PPTP_CALL_DISCONNECT_NOTIFY] = sizeof(struct PptpCallDisconnectNotify),
509 [PPTP_WAN_ERROR_NOTIFY] = sizeof(struct PptpWanErrorNotify),
510 [PPTP_SET_LINK_INFO] = sizeof(struct PptpSetLinkInfo),
513 /* track caller id inside control connection, call expect_related */
515 conntrack_pptp_help(struct sk_buff *skb, unsigned int protoff,
516 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
519 int dir = CTINFO2DIR(ctinfo);
520 const struct nf_ct_pptp_master *info = nfct_help_data(ct);
521 const struct tcphdr *tcph;
523 const struct pptp_pkt_hdr *pptph;
524 struct pptp_pkt_hdr _pptph;
525 struct PptpControlHeader _ctlh, *ctlh;
526 union pptp_ctrl_union _pptpReq, *pptpReq;
527 unsigned int tcplen = skb->len - protoff;
528 unsigned int datalen, reqlen, nexthdr_off;
529 int oldsstate, oldcstate;
533 #if IS_ENABLED(CONFIG_NF_NAT)
534 if (!nf_ct_is_confirmed(ct) && (ct->status & IPS_NAT_MASK)) {
535 struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
537 if (!nat && !nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC))
541 /* don't do any tracking before tcp handshake complete */
542 if (ctinfo != IP_CT_ESTABLISHED && ctinfo != IP_CT_ESTABLISHED_REPLY)
545 nexthdr_off = protoff;
546 tcph = skb_header_pointer(skb, nexthdr_off, sizeof(_tcph), &_tcph);
548 nexthdr_off += tcph->doff * 4;
549 datalen = tcplen - tcph->doff * 4;
551 pptph = skb_header_pointer(skb, nexthdr_off, sizeof(_pptph), &_pptph);
553 pr_debug("no full PPTP header, can't track\n");
556 nexthdr_off += sizeof(_pptph);
557 datalen -= sizeof(_pptph);
559 /* if it's not a control message we can't do anything with it */
560 if (ntohs(pptph->packetType) != PPTP_PACKET_CONTROL ||
561 ntohl(pptph->magicCookie) != PPTP_MAGIC_COOKIE) {
562 pr_debug("not a control packet\n");
566 ctlh = skb_header_pointer(skb, nexthdr_off, sizeof(_ctlh), &_ctlh);
569 nexthdr_off += sizeof(_ctlh);
570 datalen -= sizeof(_ctlh);
573 msg = ntohs(ctlh->messageType);
574 if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg])
576 if (reqlen > sizeof(*pptpReq))
577 reqlen = sizeof(*pptpReq);
579 pptpReq = skb_header_pointer(skb, nexthdr_off, reqlen, &_pptpReq);
583 oldsstate = info->sstate;
584 oldcstate = info->cstate;
586 spin_lock_bh(&nf_pptp_lock);
588 /* FIXME: We just blindly assume that the control connection is always
589 * established from PNS->PAC. However, RFC makes no guarantee */
590 if (dir == IP_CT_DIR_ORIGINAL)
591 /* client -> server (PNS -> PAC) */
592 ret = pptp_outbound_pkt(skb, protoff, ctlh, pptpReq, reqlen, ct,
595 /* server -> client (PAC -> PNS) */
596 ret = pptp_inbound_pkt(skb, protoff, ctlh, pptpReq, reqlen, ct,
598 pr_debug("sstate: %d->%d, cstate: %d->%d\n",
599 oldsstate, info->sstate, oldcstate, info->cstate);
600 spin_unlock_bh(&nf_pptp_lock);
605 static const struct nf_conntrack_expect_policy pptp_exp_policy = {
610 /* control protocol helper */
611 static struct nf_conntrack_helper pptp __read_mostly = {
614 .tuple.src.l3num = AF_INET,
615 .tuple.src.u.tcp.port = cpu_to_be16(PPTP_CONTROL_PORT),
616 .tuple.dst.protonum = IPPROTO_TCP,
617 .help = conntrack_pptp_help,
618 .destroy = pptp_destroy_siblings,
619 .expect_policy = &pptp_exp_policy,
622 static int __init nf_conntrack_pptp_init(void)
624 NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_pptp_master));
626 return nf_conntrack_helper_register(&pptp);
629 static void __exit nf_conntrack_pptp_fini(void)
631 nf_conntrack_helper_unregister(&pptp);
634 module_init(nf_conntrack_pptp_init);
635 module_exit(nf_conntrack_pptp_fini);