Commit | Line | Data |
---|---|---|
926b50f9 HW |
1 | /* |
2 | * ip_conntrack_pptp.c - Version 3.0 | |
3 | * | |
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 | |
11 | * | |
12 | * (C) 2000-2005 by Harald Welte <laforge@gnumonks.org> | |
13 | * | |
14 | * Development of this code funded by Astaro AG (http://www.astaro.com/) | |
15 | * | |
16 | * Limitations: | |
17 | * - We blindly assume that control connections are always | |
18 | * established in PNS->PAC direction. This is a violation | |
19 | * of RFFC2673 | |
20 | * - We can only support one single call within each session | |
21 | * | |
22 | * TODO: | |
edd5a329 | 23 | * - testing of incoming PPTP calls |
926b50f9 | 24 | * |
edd5a329 | 25 | * Changes: |
926b50f9 | 26 | * 2002-02-05 - Version 1.3 |
edd5a329 | 27 | * - Call ip_conntrack_unexpect_related() from |
926b50f9 HW |
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 | |
46 | * | |
47 | */ | |
48 | ||
926b50f9 HW |
49 | #include <linux/module.h> |
50 | #include <linux/netfilter.h> | |
51 | #include <linux/ip.h> | |
52 | #include <net/checksum.h> | |
53 | #include <net/tcp.h> | |
54 | ||
55 | #include <linux/netfilter_ipv4/ip_conntrack.h> | |
56 | #include <linux/netfilter_ipv4/ip_conntrack_core.h> | |
57 | #include <linux/netfilter_ipv4/ip_conntrack_helper.h> | |
58 | #include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h> | |
59 | #include <linux/netfilter_ipv4/ip_conntrack_pptp.h> | |
60 | ||
61 | #define IP_CT_PPTP_VERSION "3.1" | |
62 | ||
63 | MODULE_LICENSE("GPL"); | |
64 | MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); | |
65 | MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP"); | |
66 | ||
67 | static DEFINE_SPINLOCK(ip_pptp_lock); | |
68 | ||
69 | int | |
70 | (*ip_nat_pptp_hook_outbound)(struct sk_buff **pskb, | |
71 | struct ip_conntrack *ct, | |
72 | enum ip_conntrack_info ctinfo, | |
73 | struct PptpControlHeader *ctlh, | |
74 | union pptp_ctrl_union *pptpReq); | |
75 | ||
76 | int | |
77 | (*ip_nat_pptp_hook_inbound)(struct sk_buff **pskb, | |
78 | struct ip_conntrack *ct, | |
79 | enum ip_conntrack_info ctinfo, | |
80 | struct PptpControlHeader *ctlh, | |
81 | union pptp_ctrl_union *pptpReq); | |
82 | ||
cf9f8152 | 83 | void |
926b50f9 HW |
84 | (*ip_nat_pptp_hook_exp_gre)(struct ip_conntrack_expect *expect_orig, |
85 | struct ip_conntrack_expect *expect_reply); | |
86 | ||
87 | void | |
88 | (*ip_nat_pptp_hook_expectfn)(struct ip_conntrack *ct, | |
89 | struct ip_conntrack_expect *exp); | |
90 | ||
91 | #if 0 | |
92 | /* PptpControlMessageType names */ | |
93 | const char *pptp_msg_name[] = { | |
94 | "UNKNOWN_MESSAGE", | |
95 | "START_SESSION_REQUEST", | |
96 | "START_SESSION_REPLY", | |
97 | "STOP_SESSION_REQUEST", | |
98 | "STOP_SESSION_REPLY", | |
99 | "ECHO_REQUEST", | |
100 | "ECHO_REPLY", | |
101 | "OUT_CALL_REQUEST", | |
102 | "OUT_CALL_REPLY", | |
103 | "IN_CALL_REQUEST", | |
104 | "IN_CALL_REPLY", | |
105 | "IN_CALL_CONNECT", | |
106 | "CALL_CLEAR_REQUEST", | |
107 | "CALL_DISCONNECT_NOTIFY", | |
108 | "WAN_ERROR_NOTIFY", | |
109 | "SET_LINK_INFO" | |
110 | }; | |
111 | EXPORT_SYMBOL(pptp_msg_name); | |
112 | #define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, __FUNCTION__, ## args) | |
113 | #else | |
114 | #define DEBUGP(format, args...) | |
115 | #endif | |
116 | ||
117 | #define SECS *HZ | |
118 | #define MINS * 60 SECS | |
119 | #define HOURS * 60 MINS | |
120 | ||
121 | #define PPTP_GRE_TIMEOUT (10 MINS) | |
122 | #define PPTP_GRE_STREAM_TIMEOUT (5 HOURS) | |
123 | ||
124 | static void pptp_expectfn(struct ip_conntrack *ct, | |
125 | struct ip_conntrack_expect *exp) | |
126 | { | |
127 | DEBUGP("increasing timeouts\n"); | |
128 | ||
129 | /* increase timeout of GRE data channel conntrack entry */ | |
130 | ct->proto.gre.timeout = PPTP_GRE_TIMEOUT; | |
131 | ct->proto.gre.stream_timeout = PPTP_GRE_STREAM_TIMEOUT; | |
132 | ||
133 | /* Can you see how rusty this code is, compared with the pre-2.6.11 | |
134 | * one? That's what happened to my shiny newnat of 2002 ;( -HW */ | |
135 | ||
136 | if (!ip_nat_pptp_hook_expectfn) { | |
137 | struct ip_conntrack_tuple inv_t; | |
138 | struct ip_conntrack_expect *exp_other; | |
139 | ||
140 | /* obviously this tuple inversion only works until you do NAT */ | |
141 | invert_tuplepr(&inv_t, &exp->tuple); | |
142 | DEBUGP("trying to unexpect other dir: "); | |
143 | DUMP_TUPLE(&inv_t); | |
edd5a329 | 144 | |
926b50f9 HW |
145 | exp_other = ip_conntrack_expect_find(&inv_t); |
146 | if (exp_other) { | |
147 | /* delete other expectation. */ | |
148 | DEBUGP("found\n"); | |
149 | ip_conntrack_unexpect_related(exp_other); | |
150 | ip_conntrack_expect_put(exp_other); | |
151 | } else { | |
152 | DEBUGP("not found\n"); | |
153 | } | |
154 | } else { | |
155 | /* we need more than simple inversion */ | |
156 | ip_nat_pptp_hook_expectfn(ct, exp); | |
157 | } | |
158 | } | |
159 | ||
160 | static int destroy_sibling_or_exp(const struct ip_conntrack_tuple *t) | |
161 | { | |
162 | struct ip_conntrack_tuple_hash *h; | |
163 | struct ip_conntrack_expect *exp; | |
164 | ||
165 | DEBUGP("trying to timeout ct or exp for tuple "); | |
166 | DUMP_TUPLE(t); | |
167 | ||
168 | h = ip_conntrack_find_get(t, NULL); | |
169 | if (h) { | |
170 | struct ip_conntrack *sibling = tuplehash_to_ctrack(h); | |
171 | DEBUGP("setting timeout of conntrack %p to 0\n", sibling); | |
172 | sibling->proto.gre.timeout = 0; | |
173 | sibling->proto.gre.stream_timeout = 0; | |
926b50f9 HW |
174 | if (del_timer(&sibling->timeout)) |
175 | sibling->timeout.function((unsigned long)sibling); | |
176 | ip_conntrack_put(sibling); | |
177 | return 1; | |
178 | } else { | |
179 | exp = ip_conntrack_expect_find(t); | |
180 | if (exp) { | |
181 | DEBUGP("unexpect_related of expect %p\n", exp); | |
182 | ip_conntrack_unexpect_related(exp); | |
183 | ip_conntrack_expect_put(exp); | |
184 | return 1; | |
185 | } | |
186 | } | |
187 | ||
188 | return 0; | |
189 | } | |
190 | ||
191 | ||
192 | /* timeout GRE data connections */ | |
193 | static void pptp_destroy_siblings(struct ip_conntrack *ct) | |
194 | { | |
195 | struct ip_conntrack_tuple t; | |
196 | ||
fd5e3bef | 197 | ip_ct_gre_keymap_destroy(ct); |
edd5a329 | 198 | /* Since ct->sibling_list has literally rusted away in 2.6.11, |
926b50f9 HW |
199 | * we now need another way to find out about our sibling |
200 | * contrack and expects... -HW */ | |
201 | ||
202 | /* try original (pns->pac) tuple */ | |
203 | memcpy(&t, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(t)); | |
204 | t.dst.protonum = IPPROTO_GRE; | |
955b9442 PM |
205 | t.src.u.gre.key = ct->help.ct_pptp_info.pns_call_id; |
206 | t.dst.u.gre.key = ct->help.ct_pptp_info.pac_call_id; | |
926b50f9 HW |
207 | |
208 | if (!destroy_sibling_or_exp(&t)) | |
209 | DEBUGP("failed to timeout original pns->pac ct/exp\n"); | |
210 | ||
211 | /* try reply (pac->pns) tuple */ | |
212 | memcpy(&t, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, sizeof(t)); | |
213 | t.dst.protonum = IPPROTO_GRE; | |
955b9442 PM |
214 | t.src.u.gre.key = ct->help.ct_pptp_info.pac_call_id; |
215 | t.dst.u.gre.key = ct->help.ct_pptp_info.pns_call_id; | |
926b50f9 HW |
216 | |
217 | if (!destroy_sibling_or_exp(&t)) | |
218 | DEBUGP("failed to timeout reply pac->pns ct/exp\n"); | |
219 | } | |
220 | ||
221 | /* expect GRE connections (PNS->PAC and PAC->PNS direction) */ | |
222 | static inline int | |
cf9f8152 | 223 | exp_gre(struct ip_conntrack *ct, |
67497205 AD |
224 | __be16 callid, |
225 | __be16 peer_callid) | |
926b50f9 | 226 | { |
926b50f9 HW |
227 | struct ip_conntrack_expect *exp_orig, *exp_reply; |
228 | int ret = 1; | |
229 | ||
cf9f8152 | 230 | exp_orig = ip_conntrack_expect_alloc(ct); |
926b50f9 HW |
231 | if (exp_orig == NULL) |
232 | goto out; | |
233 | ||
cf9f8152 | 234 | exp_reply = ip_conntrack_expect_alloc(ct); |
926b50f9 HW |
235 | if (exp_reply == NULL) |
236 | goto out_put_orig; | |
237 | ||
cf9f8152 PM |
238 | /* original direction, PNS->PAC */ |
239 | exp_orig->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; | |
240 | exp_orig->tuple.src.u.gre.key = peer_callid; | |
241 | exp_orig->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; | |
242 | exp_orig->tuple.dst.u.gre.key = callid; | |
243 | exp_orig->tuple.dst.protonum = IPPROTO_GRE; | |
926b50f9 | 244 | |
cdcb71bf | 245 | exp_orig->mask.src.ip = htonl(0xffffffff); |
926b50f9 | 246 | exp_orig->mask.src.u.all = 0; |
67497205 | 247 | exp_orig->mask.dst.u.gre.key = htons(0xffff); |
cdcb71bf | 248 | exp_orig->mask.dst.ip = htonl(0xffffffff); |
926b50f9 | 249 | exp_orig->mask.dst.protonum = 0xff; |
edd5a329 | 250 | |
cf9f8152 | 251 | exp_orig->master = ct; |
926b50f9 HW |
252 | exp_orig->expectfn = pptp_expectfn; |
253 | exp_orig->flags = 0; | |
254 | ||
926b50f9 HW |
255 | /* both expectations are identical apart from tuple */ |
256 | memcpy(exp_reply, exp_orig, sizeof(*exp_reply)); | |
926b50f9 | 257 | |
cf9f8152 PM |
258 | /* reply direction, PAC->PNS */ |
259 | exp_reply->tuple.src.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip; | |
260 | exp_reply->tuple.src.u.gre.key = callid; | |
261 | exp_reply->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip; | |
262 | exp_reply->tuple.dst.u.gre.key = peer_callid; | |
263 | exp_reply->tuple.dst.protonum = IPPROTO_GRE; | |
926b50f9 | 264 | |
cf9f8152 PM |
265 | if (ip_nat_pptp_hook_exp_gre) |
266 | ip_nat_pptp_hook_exp_gre(exp_orig, exp_reply); | |
267 | if (ip_conntrack_expect_related(exp_orig) != 0) | |
268 | goto out_put_both; | |
269 | if (ip_conntrack_expect_related(exp_reply) != 0) | |
270 | goto out_unexpect_orig; | |
271 | ||
272 | /* Add GRE keymap entries */ | |
273 | if (ip_ct_gre_keymap_add(ct, &exp_orig->tuple, 0) != 0) | |
274 | goto out_unexpect_both; | |
275 | if (ip_ct_gre_keymap_add(ct, &exp_reply->tuple, 1) != 0) { | |
276 | ip_ct_gre_keymap_destroy(ct); | |
277 | goto out_unexpect_both; | |
926b50f9 | 278 | } |
cf9f8152 | 279 | ret = 0; |
926b50f9 HW |
280 | |
281 | out_put_both: | |
282 | ip_conntrack_expect_put(exp_reply); | |
283 | out_put_orig: | |
284 | ip_conntrack_expect_put(exp_orig); | |
285 | out: | |
286 | return ret; | |
287 | ||
288 | out_unexpect_both: | |
289 | ip_conntrack_unexpect_related(exp_reply); | |
290 | out_unexpect_orig: | |
291 | ip_conntrack_unexpect_related(exp_orig); | |
292 | goto out_put_both; | |
293 | } | |
294 | ||
edd5a329 | 295 | static inline int |
926b50f9 | 296 | pptp_inbound_pkt(struct sk_buff **pskb, |
4c651756 PM |
297 | struct PptpControlHeader *ctlh, |
298 | union pptp_ctrl_union *pptpReq, | |
299 | unsigned int reqlen, | |
926b50f9 HW |
300 | struct ip_conntrack *ct, |
301 | enum ip_conntrack_info ctinfo) | |
302 | { | |
926b50f9 | 303 | struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; |
67497205 | 304 | u_int16_t msg; |
87a0117a | 305 | __be16 cid = 0, pcid = 0; |
926b50f9 | 306 | |
926b50f9 HW |
307 | msg = ntohs(ctlh->messageType); |
308 | DEBUGP("inbound control message %s\n", pptp_msg_name[msg]); | |
309 | ||
310 | switch (msg) { | |
311 | case PPTP_START_SESSION_REPLY: | |
926b50f9 | 312 | /* server confirms new control session */ |
87a0117a PM |
313 | if (info->sstate < PPTP_SESSION_REQUESTED) |
314 | goto invalid; | |
926b50f9 HW |
315 | if (pptpReq->srep.resultCode == PPTP_START_OK) |
316 | info->sstate = PPTP_SESSION_CONFIRMED; | |
edd5a329 | 317 | else |
926b50f9 HW |
318 | info->sstate = PPTP_SESSION_ERROR; |
319 | break; | |
320 | ||
321 | case PPTP_STOP_SESSION_REPLY: | |
926b50f9 | 322 | /* server confirms end of control session */ |
87a0117a PM |
323 | if (info->sstate > PPTP_SESSION_STOPREQ) |
324 | goto invalid; | |
926b50f9 HW |
325 | if (pptpReq->strep.resultCode == PPTP_STOP_OK) |
326 | info->sstate = PPTP_SESSION_NONE; | |
327 | else | |
328 | info->sstate = PPTP_SESSION_ERROR; | |
329 | break; | |
330 | ||
331 | case PPTP_OUT_CALL_REPLY: | |
926b50f9 | 332 | /* server accepted call, we now expect GRE frames */ |
87a0117a PM |
333 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
334 | goto invalid; | |
926b50f9 | 335 | if (info->cstate != PPTP_CALL_OUT_REQ && |
87a0117a PM |
336 | info->cstate != PPTP_CALL_OUT_CONF) |
337 | goto invalid; | |
338 | ||
857c06da PM |
339 | cid = pptpReq->ocack.callID; |
340 | pcid = pptpReq->ocack.peersCallID; | |
87a0117a PM |
341 | if (info->pns_call_id != pcid) |
342 | goto invalid; | |
edd5a329 | 343 | DEBUGP("%s, CID=%X, PCID=%X\n", pptp_msg_name[msg], |
857c06da | 344 | ntohs(cid), ntohs(pcid)); |
edd5a329 | 345 | |
750a5842 PM |
346 | if (pptpReq->ocack.resultCode == PPTP_OUTCALL_CONNECT) { |
347 | info->cstate = PPTP_CALL_OUT_CONF; | |
348 | info->pac_call_id = cid; | |
349 | exp_gre(ct, cid, pcid); | |
350 | } else | |
351 | info->cstate = PPTP_CALL_NONE; | |
926b50f9 HW |
352 | break; |
353 | ||
354 | case PPTP_IN_CALL_REQUEST: | |
926b50f9 | 355 | /* server tells us about incoming call request */ |
87a0117a PM |
356 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
357 | goto invalid; | |
358 | ||
62fbe9c8 PM |
359 | cid = pptpReq->icreq.callID; |
360 | DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid)); | |
926b50f9 | 361 | info->cstate = PPTP_CALL_IN_REQ; |
62fbe9c8 | 362 | info->pac_call_id = cid; |
926b50f9 HW |
363 | break; |
364 | ||
365 | case PPTP_IN_CALL_CONNECT: | |
926b50f9 | 366 | /* server tells us about incoming call established */ |
87a0117a PM |
367 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
368 | goto invalid; | |
369 | if (info->cstate != PPTP_CALL_IN_REP && | |
370 | info->cstate != PPTP_CALL_IN_CONF) | |
371 | goto invalid; | |
926b50f9 | 372 | |
857c06da PM |
373 | pcid = pptpReq->iccon.peersCallID; |
374 | cid = info->pac_call_id; | |
926b50f9 | 375 | |
87a0117a PM |
376 | if (info->pns_call_id != pcid) |
377 | goto invalid; | |
926b50f9 | 378 | |
857c06da | 379 | DEBUGP("%s, PCID=%X\n", pptp_msg_name[msg], ntohs(pcid)); |
926b50f9 HW |
380 | info->cstate = PPTP_CALL_IN_CONF; |
381 | ||
382 | /* we expect a GRE connection from PAC to PNS */ | |
857c06da | 383 | exp_gre(ct, cid, pcid); |
926b50f9 HW |
384 | break; |
385 | ||
386 | case PPTP_CALL_DISCONNECT_NOTIFY: | |
926b50f9 | 387 | /* server confirms disconnect */ |
857c06da PM |
388 | cid = pptpReq->disc.callID; |
389 | DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid)); | |
926b50f9 HW |
390 | info->cstate = PPTP_CALL_NONE; |
391 | ||
392 | /* untrack this call id, unexpect GRE packets */ | |
393 | pptp_destroy_siblings(ct); | |
394 | break; | |
395 | ||
396 | case PPTP_WAN_ERROR_NOTIFY: | |
926b50f9 HW |
397 | case PPTP_ECHO_REQUEST: |
398 | case PPTP_ECHO_REPLY: | |
399 | /* I don't have to explain these ;) */ | |
400 | break; | |
401 | default: | |
87a0117a | 402 | goto invalid; |
926b50f9 HW |
403 | } |
404 | ||
926b50f9 HW |
405 | if (ip_nat_pptp_hook_inbound) |
406 | return ip_nat_pptp_hook_inbound(pskb, ct, ctinfo, ctlh, | |
407 | pptpReq); | |
926b50f9 HW |
408 | return NF_ACCEPT; |
409 | ||
87a0117a PM |
410 | invalid: |
411 | DEBUGP("invalid %s: type=%d cid=%u pcid=%u " | |
412 | "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n", | |
413 | msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0], | |
414 | msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate, | |
415 | ntohs(info->pns_call_id), ntohs(info->pac_call_id)); | |
416 | return NF_ACCEPT; | |
926b50f9 HW |
417 | } |
418 | ||
419 | static inline int | |
420 | pptp_outbound_pkt(struct sk_buff **pskb, | |
4c651756 PM |
421 | struct PptpControlHeader *ctlh, |
422 | union pptp_ctrl_union *pptpReq, | |
423 | unsigned int reqlen, | |
926b50f9 HW |
424 | struct ip_conntrack *ct, |
425 | enum ip_conntrack_info ctinfo) | |
426 | { | |
926b50f9 | 427 | struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; |
67497205 | 428 | u_int16_t msg; |
87a0117a | 429 | __be16 cid = 0, pcid = 0; |
926b50f9 | 430 | |
926b50f9 HW |
431 | msg = ntohs(ctlh->messageType); |
432 | DEBUGP("outbound control message %s\n", pptp_msg_name[msg]); | |
433 | ||
434 | switch (msg) { | |
435 | case PPTP_START_SESSION_REQUEST: | |
436 | /* client requests for new control session */ | |
87a0117a PM |
437 | if (info->sstate != PPTP_SESSION_NONE) |
438 | goto invalid; | |
926b50f9 HW |
439 | info->sstate = PPTP_SESSION_REQUESTED; |
440 | break; | |
441 | case PPTP_STOP_SESSION_REQUEST: | |
442 | /* client requests end of control session */ | |
443 | info->sstate = PPTP_SESSION_STOPREQ; | |
444 | break; | |
445 | ||
446 | case PPTP_OUT_CALL_REQUEST: | |
926b50f9 | 447 | /* client initiating connection to server */ |
87a0117a PM |
448 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
449 | goto invalid; | |
926b50f9 HW |
450 | info->cstate = PPTP_CALL_OUT_REQ; |
451 | /* track PNS call id */ | |
857c06da PM |
452 | cid = pptpReq->ocreq.callID; |
453 | DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid)); | |
454 | info->pns_call_id = cid; | |
926b50f9 HW |
455 | break; |
456 | case PPTP_IN_CALL_REPLY: | |
926b50f9 | 457 | /* client answers incoming call */ |
87a0117a PM |
458 | if (info->cstate != PPTP_CALL_IN_REQ && |
459 | info->cstate != PPTP_CALL_IN_REP) | |
460 | goto invalid; | |
461 | ||
62fbe9c8 | 462 | cid = pptpReq->icack.callID; |
857c06da | 463 | pcid = pptpReq->icack.peersCallID; |
87a0117a PM |
464 | if (info->pac_call_id != pcid) |
465 | goto invalid; | |
62fbe9c8 PM |
466 | DEBUGP("%s, CID=%X PCID=%X\n", pptp_msg_name[msg], |
467 | ntohs(cid), ntohs(pcid)); | |
750a5842 PM |
468 | |
469 | if (pptpReq->icack.resultCode == PPTP_INCALL_ACCEPT) { | |
470 | /* part two of the three-way handshake */ | |
471 | info->cstate = PPTP_CALL_IN_REP; | |
62fbe9c8 | 472 | info->pns_call_id = cid; |
750a5842 PM |
473 | } else |
474 | info->cstate = PPTP_CALL_NONE; | |
926b50f9 HW |
475 | break; |
476 | ||
477 | case PPTP_CALL_CLEAR_REQUEST: | |
478 | /* client requests hangup of call */ | |
87a0117a PM |
479 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
480 | goto invalid; | |
926b50f9 HW |
481 | /* FUTURE: iterate over all calls and check if |
482 | * call ID is valid. We don't do this without newnat, | |
483 | * because we only know about last call */ | |
484 | info->cstate = PPTP_CALL_CLEAR_REQ; | |
485 | break; | |
486 | case PPTP_SET_LINK_INFO: | |
926b50f9 HW |
487 | case PPTP_ECHO_REQUEST: |
488 | case PPTP_ECHO_REPLY: | |
489 | /* I don't have to explain these ;) */ | |
490 | break; | |
491 | default: | |
87a0117a | 492 | goto invalid; |
926b50f9 | 493 | } |
edd5a329 | 494 | |
926b50f9 HW |
495 | if (ip_nat_pptp_hook_outbound) |
496 | return ip_nat_pptp_hook_outbound(pskb, ct, ctinfo, ctlh, | |
497 | pptpReq); | |
87a0117a | 498 | return NF_ACCEPT; |
926b50f9 | 499 | |
87a0117a PM |
500 | invalid: |
501 | DEBUGP("invalid %s: type=%d cid=%u pcid=%u " | |
502 | "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n", | |
503 | msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0], | |
504 | msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate, | |
505 | ntohs(info->pns_call_id), ntohs(info->pac_call_id)); | |
926b50f9 HW |
506 | return NF_ACCEPT; |
507 | } | |
508 | ||
4c651756 PM |
509 | static const unsigned int pptp_msg_size[] = { |
510 | [PPTP_START_SESSION_REQUEST] = sizeof(struct PptpStartSessionRequest), | |
511 | [PPTP_START_SESSION_REPLY] = sizeof(struct PptpStartSessionReply), | |
512 | [PPTP_STOP_SESSION_REQUEST] = sizeof(struct PptpStopSessionRequest), | |
513 | [PPTP_STOP_SESSION_REPLY] = sizeof(struct PptpStopSessionReply), | |
514 | [PPTP_OUT_CALL_REQUEST] = sizeof(struct PptpOutCallRequest), | |
515 | [PPTP_OUT_CALL_REPLY] = sizeof(struct PptpOutCallReply), | |
516 | [PPTP_IN_CALL_REQUEST] = sizeof(struct PptpInCallRequest), | |
517 | [PPTP_IN_CALL_REPLY] = sizeof(struct PptpInCallReply), | |
518 | [PPTP_IN_CALL_CONNECT] = sizeof(struct PptpInCallConnected), | |
519 | [PPTP_CALL_CLEAR_REQUEST] = sizeof(struct PptpClearCallRequest), | |
520 | [PPTP_CALL_DISCONNECT_NOTIFY] = sizeof(struct PptpCallDisconnectNotify), | |
521 | [PPTP_WAN_ERROR_NOTIFY] = sizeof(struct PptpWanErrorNotify), | |
522 | [PPTP_SET_LINK_INFO] = sizeof(struct PptpSetLinkInfo), | |
523 | }; | |
926b50f9 HW |
524 | |
525 | /* track caller id inside control connection, call expect_related */ | |
edd5a329 | 526 | static int |
926b50f9 HW |
527 | conntrack_pptp_help(struct sk_buff **pskb, |
528 | struct ip_conntrack *ct, enum ip_conntrack_info ctinfo) | |
529 | ||
530 | { | |
926b50f9 HW |
531 | int dir = CTINFO2DIR(ctinfo); |
532 | struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; | |
4c651756 PM |
533 | struct tcphdr _tcph, *tcph; |
534 | struct pptp_pkt_hdr _pptph, *pptph; | |
535 | struct PptpControlHeader _ctlh, *ctlh; | |
536 | union pptp_ctrl_union _pptpReq, *pptpReq; | |
537 | unsigned int tcplen = (*pskb)->len - (*pskb)->nh.iph->ihl * 4; | |
538 | unsigned int datalen, reqlen, nexthdr_off; | |
926b50f9 HW |
539 | int oldsstate, oldcstate; |
540 | int ret; | |
4c651756 | 541 | u_int16_t msg; |
926b50f9 HW |
542 | |
543 | /* don't do any tracking before tcp handshake complete */ | |
edd5a329 | 544 | if (ctinfo != IP_CT_ESTABLISHED |
926b50f9 HW |
545 | && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) { |
546 | DEBUGP("ctinfo = %u, skipping\n", ctinfo); | |
547 | return NF_ACCEPT; | |
548 | } | |
edd5a329 | 549 | |
926b50f9 HW |
550 | nexthdr_off = (*pskb)->nh.iph->ihl*4; |
551 | tcph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_tcph), &_tcph); | |
552 | BUG_ON(!tcph); | |
553 | nexthdr_off += tcph->doff * 4; | |
554 | datalen = tcplen - tcph->doff * 4; | |
555 | ||
926b50f9 HW |
556 | pptph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_pptph), &_pptph); |
557 | if (!pptph) { | |
558 | DEBUGP("no full PPTP header, can't track\n"); | |
559 | return NF_ACCEPT; | |
560 | } | |
561 | nexthdr_off += sizeof(_pptph); | |
562 | datalen -= sizeof(_pptph); | |
563 | ||
564 | /* if it's not a control message we can't do anything with it */ | |
565 | if (ntohs(pptph->packetType) != PPTP_PACKET_CONTROL || | |
566 | ntohl(pptph->magicCookie) != PPTP_MAGIC_COOKIE) { | |
567 | DEBUGP("not a control packet\n"); | |
568 | return NF_ACCEPT; | |
569 | } | |
570 | ||
4c651756 PM |
571 | ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh); |
572 | if (!ctlh) | |
573 | return NF_ACCEPT; | |
574 | nexthdr_off += sizeof(_ctlh); | |
575 | datalen -= sizeof(_ctlh); | |
576 | ||
577 | reqlen = datalen; | |
578 | msg = ntohs(ctlh->messageType); | |
579 | if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg]) | |
580 | return NF_ACCEPT; | |
581 | if (reqlen > sizeof(*pptpReq)) | |
582 | reqlen = sizeof(*pptpReq); | |
583 | ||
584 | pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq); | |
585 | if (!pptpReq) | |
586 | return NF_ACCEPT; | |
587 | ||
926b50f9 HW |
588 | oldsstate = info->sstate; |
589 | oldcstate = info->cstate; | |
590 | ||
591 | spin_lock_bh(&ip_pptp_lock); | |
592 | ||
593 | /* FIXME: We just blindly assume that the control connection is always | |
594 | * established from PNS->PAC. However, RFC makes no guarantee */ | |
595 | if (dir == IP_CT_DIR_ORIGINAL) | |
596 | /* client -> server (PNS -> PAC) */ | |
4c651756 | 597 | ret = pptp_outbound_pkt(pskb, ctlh, pptpReq, reqlen, ct, |
926b50f9 HW |
598 | ctinfo); |
599 | else | |
600 | /* server -> client (PAC -> PNS) */ | |
4c651756 | 601 | ret = pptp_inbound_pkt(pskb, ctlh, pptpReq, reqlen, ct, |
926b50f9 HW |
602 | ctinfo); |
603 | DEBUGP("sstate: %d->%d, cstate: %d->%d\n", | |
604 | oldsstate, info->sstate, oldcstate, info->cstate); | |
605 | spin_unlock_bh(&ip_pptp_lock); | |
606 | ||
607 | return ret; | |
608 | } | |
609 | ||
610 | /* control protocol helper */ | |
edd5a329 | 611 | static struct ip_conntrack_helper pptp = { |
926b50f9 | 612 | .list = { NULL, NULL }, |
edd5a329 | 613 | .name = "pptp", |
926b50f9 HW |
614 | .me = THIS_MODULE, |
615 | .max_expected = 2, | |
616 | .timeout = 5 * 60, | |
edd5a329 PM |
617 | .tuple = { .src = { .ip = 0, |
618 | .u = { .tcp = { .port = | |
619 | __constant_htons(PPTP_CONTROL_PORT) } } | |
620 | }, | |
621 | .dst = { .ip = 0, | |
926b50f9 HW |
622 | .u = { .all = 0 }, |
623 | .protonum = IPPROTO_TCP | |
edd5a329 | 624 | } |
926b50f9 | 625 | }, |
edd5a329 PM |
626 | .mask = { .src = { .ip = 0, |
627 | .u = { .tcp = { .port = __constant_htons(0xffff) } } | |
628 | }, | |
629 | .dst = { .ip = 0, | |
926b50f9 | 630 | .u = { .all = 0 }, |
edd5a329 PM |
631 | .protonum = 0xff |
632 | } | |
926b50f9 | 633 | }, |
4c5de695 PM |
634 | .help = conntrack_pptp_help, |
635 | .destroy = pptp_destroy_siblings, | |
926b50f9 HW |
636 | }; |
637 | ||
a7768097 | 638 | extern void ip_ct_proto_gre_fini(void); |
926b50f9 HW |
639 | extern int __init ip_ct_proto_gre_init(void); |
640 | ||
641 | /* ip_conntrack_pptp initialization */ | |
65b4b4e8 | 642 | static int __init ip_conntrack_helper_pptp_init(void) |
926b50f9 HW |
643 | { |
644 | int retcode; | |
edd5a329 | 645 | |
926b50f9 HW |
646 | retcode = ip_ct_proto_gre_init(); |
647 | if (retcode < 0) | |
648 | return retcode; | |
649 | ||
650 | DEBUGP(" registering helper\n"); | |
651 | if ((retcode = ip_conntrack_helper_register(&pptp))) { | |
652 | printk(KERN_ERR "Unable to register conntrack application " | |
653 | "helper for pptp: %d\n", retcode); | |
654 | ip_ct_proto_gre_fini(); | |
655 | return retcode; | |
656 | } | |
657 | ||
658 | printk("ip_conntrack_pptp version %s loaded\n", IP_CT_PPTP_VERSION); | |
659 | return 0; | |
660 | } | |
661 | ||
65b4b4e8 | 662 | static void __exit ip_conntrack_helper_pptp_fini(void) |
926b50f9 HW |
663 | { |
664 | ip_conntrack_helper_unregister(&pptp); | |
665 | ip_ct_proto_gre_fini(); | |
666 | printk("ip_conntrack_pptp version %s unloaded\n", IP_CT_PPTP_VERSION); | |
667 | } | |
668 | ||
65b4b4e8 AM |
669 | module_init(ip_conntrack_helper_pptp_init); |
670 | module_exit(ip_conntrack_helper_pptp_fini); | |
926b50f9 HW |
671 | |
672 | EXPORT_SYMBOL(ip_nat_pptp_hook_outbound); | |
673 | EXPORT_SYMBOL(ip_nat_pptp_hook_inbound); | |
674 | EXPORT_SYMBOL(ip_nat_pptp_hook_exp_gre); | |
675 | EXPORT_SYMBOL(ip_nat_pptp_hook_expectfn); |