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Commit | Line | Data |
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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 | { | |
337fbc41 PM |
127 | typeof(ip_nat_pptp_hook_expectfn) ip_nat_pptp_expectfn; |
128 | ||
926b50f9 HW |
129 | DEBUGP("increasing timeouts\n"); |
130 | ||
131 | /* increase timeout of GRE data channel conntrack entry */ | |
132 | ct->proto.gre.timeout = PPTP_GRE_TIMEOUT; | |
133 | ct->proto.gre.stream_timeout = PPTP_GRE_STREAM_TIMEOUT; | |
134 | ||
135 | /* Can you see how rusty this code is, compared with the pre-2.6.11 | |
136 | * one? That's what happened to my shiny newnat of 2002 ;( -HW */ | |
137 | ||
337fbc41 PM |
138 | rcu_read_lock(); |
139 | ip_nat_pptp_expectfn = rcu_dereference(ip_nat_pptp_hook_expectfn); | |
140 | if (!ip_nat_pptp_expectfn) { | |
926b50f9 HW |
141 | struct ip_conntrack_tuple inv_t; |
142 | struct ip_conntrack_expect *exp_other; | |
143 | ||
144 | /* obviously this tuple inversion only works until you do NAT */ | |
145 | invert_tuplepr(&inv_t, &exp->tuple); | |
146 | DEBUGP("trying to unexpect other dir: "); | |
147 | DUMP_TUPLE(&inv_t); | |
edd5a329 | 148 | |
468ec44b | 149 | exp_other = ip_conntrack_expect_find_get(&inv_t); |
926b50f9 HW |
150 | if (exp_other) { |
151 | /* delete other expectation. */ | |
152 | DEBUGP("found\n"); | |
153 | ip_conntrack_unexpect_related(exp_other); | |
154 | ip_conntrack_expect_put(exp_other); | |
155 | } else { | |
156 | DEBUGP("not found\n"); | |
157 | } | |
158 | } else { | |
159 | /* we need more than simple inversion */ | |
337fbc41 | 160 | ip_nat_pptp_expectfn(ct, exp); |
926b50f9 | 161 | } |
337fbc41 | 162 | rcu_read_unlock(); |
926b50f9 HW |
163 | } |
164 | ||
165 | static int destroy_sibling_or_exp(const struct ip_conntrack_tuple *t) | |
166 | { | |
167 | struct ip_conntrack_tuple_hash *h; | |
168 | struct ip_conntrack_expect *exp; | |
169 | ||
170 | DEBUGP("trying to timeout ct or exp for tuple "); | |
171 | DUMP_TUPLE(t); | |
172 | ||
173 | h = ip_conntrack_find_get(t, NULL); | |
174 | if (h) { | |
175 | struct ip_conntrack *sibling = tuplehash_to_ctrack(h); | |
176 | DEBUGP("setting timeout of conntrack %p to 0\n", sibling); | |
177 | sibling->proto.gre.timeout = 0; | |
178 | sibling->proto.gre.stream_timeout = 0; | |
926b50f9 HW |
179 | if (del_timer(&sibling->timeout)) |
180 | sibling->timeout.function((unsigned long)sibling); | |
181 | ip_conntrack_put(sibling); | |
182 | return 1; | |
183 | } else { | |
468ec44b | 184 | exp = ip_conntrack_expect_find_get(t); |
926b50f9 HW |
185 | if (exp) { |
186 | DEBUGP("unexpect_related of expect %p\n", exp); | |
187 | ip_conntrack_unexpect_related(exp); | |
188 | ip_conntrack_expect_put(exp); | |
189 | return 1; | |
190 | } | |
191 | } | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
196 | ||
197 | /* timeout GRE data connections */ | |
198 | static void pptp_destroy_siblings(struct ip_conntrack *ct) | |
199 | { | |
200 | struct ip_conntrack_tuple t; | |
201 | ||
fd5e3bef | 202 | ip_ct_gre_keymap_destroy(ct); |
edd5a329 | 203 | /* Since ct->sibling_list has literally rusted away in 2.6.11, |
926b50f9 HW |
204 | * we now need another way to find out about our sibling |
205 | * contrack and expects... -HW */ | |
206 | ||
207 | /* try original (pns->pac) tuple */ | |
208 | memcpy(&t, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(t)); | |
209 | t.dst.protonum = IPPROTO_GRE; | |
955b9442 PM |
210 | t.src.u.gre.key = ct->help.ct_pptp_info.pns_call_id; |
211 | t.dst.u.gre.key = ct->help.ct_pptp_info.pac_call_id; | |
926b50f9 HW |
212 | |
213 | if (!destroy_sibling_or_exp(&t)) | |
214 | DEBUGP("failed to timeout original pns->pac ct/exp\n"); | |
215 | ||
216 | /* try reply (pac->pns) tuple */ | |
217 | memcpy(&t, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, sizeof(t)); | |
218 | t.dst.protonum = IPPROTO_GRE; | |
955b9442 PM |
219 | t.src.u.gre.key = ct->help.ct_pptp_info.pac_call_id; |
220 | t.dst.u.gre.key = ct->help.ct_pptp_info.pns_call_id; | |
926b50f9 HW |
221 | |
222 | if (!destroy_sibling_or_exp(&t)) | |
223 | DEBUGP("failed to timeout reply pac->pns ct/exp\n"); | |
224 | } | |
225 | ||
226 | /* expect GRE connections (PNS->PAC and PAC->PNS direction) */ | |
227 | static inline int | |
cf9f8152 | 228 | exp_gre(struct ip_conntrack *ct, |
67497205 AD |
229 | __be16 callid, |
230 | __be16 peer_callid) | |
926b50f9 | 231 | { |
926b50f9 HW |
232 | struct ip_conntrack_expect *exp_orig, *exp_reply; |
233 | int ret = 1; | |
337fbc41 | 234 | typeof(ip_nat_pptp_hook_exp_gre) ip_nat_pptp_exp_gre; |
926b50f9 | 235 | |
cf9f8152 | 236 | exp_orig = ip_conntrack_expect_alloc(ct); |
926b50f9 HW |
237 | if (exp_orig == NULL) |
238 | goto out; | |
239 | ||
cf9f8152 | 240 | exp_reply = ip_conntrack_expect_alloc(ct); |
926b50f9 HW |
241 | if (exp_reply == NULL) |
242 | goto out_put_orig; | |
243 | ||
cf9f8152 PM |
244 | /* original direction, PNS->PAC */ |
245 | exp_orig->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; | |
246 | exp_orig->tuple.src.u.gre.key = peer_callid; | |
247 | exp_orig->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; | |
248 | exp_orig->tuple.dst.u.gre.key = callid; | |
249 | exp_orig->tuple.dst.protonum = IPPROTO_GRE; | |
926b50f9 | 250 | |
cdcb71bf | 251 | exp_orig->mask.src.ip = htonl(0xffffffff); |
926b50f9 | 252 | exp_orig->mask.src.u.all = 0; |
67497205 | 253 | exp_orig->mask.dst.u.gre.key = htons(0xffff); |
cdcb71bf | 254 | exp_orig->mask.dst.ip = htonl(0xffffffff); |
926b50f9 | 255 | exp_orig->mask.dst.protonum = 0xff; |
edd5a329 | 256 | |
cf9f8152 | 257 | exp_orig->master = ct; |
926b50f9 HW |
258 | exp_orig->expectfn = pptp_expectfn; |
259 | exp_orig->flags = 0; | |
260 | ||
926b50f9 HW |
261 | /* both expectations are identical apart from tuple */ |
262 | memcpy(exp_reply, exp_orig, sizeof(*exp_reply)); | |
926b50f9 | 263 | |
cf9f8152 PM |
264 | /* reply direction, PAC->PNS */ |
265 | exp_reply->tuple.src.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip; | |
266 | exp_reply->tuple.src.u.gre.key = callid; | |
267 | exp_reply->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip; | |
268 | exp_reply->tuple.dst.u.gre.key = peer_callid; | |
269 | exp_reply->tuple.dst.protonum = IPPROTO_GRE; | |
926b50f9 | 270 | |
337fbc41 PM |
271 | ip_nat_pptp_exp_gre = rcu_dereference(ip_nat_pptp_hook_exp_gre); |
272 | if (ip_nat_pptp_exp_gre) | |
273 | ip_nat_pptp_exp_gre(exp_orig, exp_reply); | |
cf9f8152 PM |
274 | if (ip_conntrack_expect_related(exp_orig) != 0) |
275 | goto out_put_both; | |
276 | if (ip_conntrack_expect_related(exp_reply) != 0) | |
277 | goto out_unexpect_orig; | |
278 | ||
279 | /* Add GRE keymap entries */ | |
280 | if (ip_ct_gre_keymap_add(ct, &exp_orig->tuple, 0) != 0) | |
281 | goto out_unexpect_both; | |
282 | if (ip_ct_gre_keymap_add(ct, &exp_reply->tuple, 1) != 0) { | |
283 | ip_ct_gre_keymap_destroy(ct); | |
284 | goto out_unexpect_both; | |
926b50f9 | 285 | } |
cf9f8152 | 286 | ret = 0; |
926b50f9 HW |
287 | |
288 | out_put_both: | |
289 | ip_conntrack_expect_put(exp_reply); | |
290 | out_put_orig: | |
291 | ip_conntrack_expect_put(exp_orig); | |
292 | out: | |
293 | return ret; | |
294 | ||
295 | out_unexpect_both: | |
296 | ip_conntrack_unexpect_related(exp_reply); | |
297 | out_unexpect_orig: | |
298 | ip_conntrack_unexpect_related(exp_orig); | |
299 | goto out_put_both; | |
300 | } | |
301 | ||
edd5a329 | 302 | static inline int |
926b50f9 | 303 | pptp_inbound_pkt(struct sk_buff **pskb, |
4c651756 PM |
304 | struct PptpControlHeader *ctlh, |
305 | union pptp_ctrl_union *pptpReq, | |
306 | unsigned int reqlen, | |
926b50f9 HW |
307 | struct ip_conntrack *ct, |
308 | enum ip_conntrack_info ctinfo) | |
309 | { | |
926b50f9 | 310 | struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; |
67497205 | 311 | u_int16_t msg; |
87a0117a | 312 | __be16 cid = 0, pcid = 0; |
337fbc41 | 313 | typeof(ip_nat_pptp_hook_inbound) ip_nat_pptp_inbound; |
926b50f9 | 314 | |
926b50f9 HW |
315 | msg = ntohs(ctlh->messageType); |
316 | DEBUGP("inbound control message %s\n", pptp_msg_name[msg]); | |
317 | ||
318 | switch (msg) { | |
319 | case PPTP_START_SESSION_REPLY: | |
926b50f9 | 320 | /* server confirms new control session */ |
87a0117a PM |
321 | if (info->sstate < PPTP_SESSION_REQUESTED) |
322 | goto invalid; | |
926b50f9 HW |
323 | if (pptpReq->srep.resultCode == PPTP_START_OK) |
324 | info->sstate = PPTP_SESSION_CONFIRMED; | |
edd5a329 | 325 | else |
926b50f9 HW |
326 | info->sstate = PPTP_SESSION_ERROR; |
327 | break; | |
328 | ||
329 | case PPTP_STOP_SESSION_REPLY: | |
926b50f9 | 330 | /* server confirms end of control session */ |
87a0117a PM |
331 | if (info->sstate > PPTP_SESSION_STOPREQ) |
332 | goto invalid; | |
926b50f9 HW |
333 | if (pptpReq->strep.resultCode == PPTP_STOP_OK) |
334 | info->sstate = PPTP_SESSION_NONE; | |
335 | else | |
336 | info->sstate = PPTP_SESSION_ERROR; | |
337 | break; | |
338 | ||
339 | case PPTP_OUT_CALL_REPLY: | |
926b50f9 | 340 | /* server accepted call, we now expect GRE frames */ |
87a0117a PM |
341 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
342 | goto invalid; | |
926b50f9 | 343 | if (info->cstate != PPTP_CALL_OUT_REQ && |
87a0117a PM |
344 | info->cstate != PPTP_CALL_OUT_CONF) |
345 | goto invalid; | |
346 | ||
857c06da PM |
347 | cid = pptpReq->ocack.callID; |
348 | pcid = pptpReq->ocack.peersCallID; | |
87a0117a PM |
349 | if (info->pns_call_id != pcid) |
350 | goto invalid; | |
edd5a329 | 351 | DEBUGP("%s, CID=%X, PCID=%X\n", pptp_msg_name[msg], |
857c06da | 352 | ntohs(cid), ntohs(pcid)); |
edd5a329 | 353 | |
750a5842 PM |
354 | if (pptpReq->ocack.resultCode == PPTP_OUTCALL_CONNECT) { |
355 | info->cstate = PPTP_CALL_OUT_CONF; | |
356 | info->pac_call_id = cid; | |
357 | exp_gre(ct, cid, pcid); | |
358 | } else | |
359 | info->cstate = PPTP_CALL_NONE; | |
926b50f9 HW |
360 | break; |
361 | ||
362 | case PPTP_IN_CALL_REQUEST: | |
926b50f9 | 363 | /* server tells us about incoming call request */ |
87a0117a PM |
364 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
365 | goto invalid; | |
366 | ||
62fbe9c8 PM |
367 | cid = pptpReq->icreq.callID; |
368 | DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid)); | |
926b50f9 | 369 | info->cstate = PPTP_CALL_IN_REQ; |
62fbe9c8 | 370 | info->pac_call_id = cid; |
926b50f9 HW |
371 | break; |
372 | ||
373 | case PPTP_IN_CALL_CONNECT: | |
926b50f9 | 374 | /* server tells us about incoming call established */ |
87a0117a PM |
375 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
376 | goto invalid; | |
377 | if (info->cstate != PPTP_CALL_IN_REP && | |
378 | info->cstate != PPTP_CALL_IN_CONF) | |
379 | goto invalid; | |
926b50f9 | 380 | |
857c06da PM |
381 | pcid = pptpReq->iccon.peersCallID; |
382 | cid = info->pac_call_id; | |
926b50f9 | 383 | |
87a0117a PM |
384 | if (info->pns_call_id != pcid) |
385 | goto invalid; | |
926b50f9 | 386 | |
857c06da | 387 | DEBUGP("%s, PCID=%X\n", pptp_msg_name[msg], ntohs(pcid)); |
926b50f9 HW |
388 | info->cstate = PPTP_CALL_IN_CONF; |
389 | ||
390 | /* we expect a GRE connection from PAC to PNS */ | |
857c06da | 391 | exp_gre(ct, cid, pcid); |
926b50f9 HW |
392 | break; |
393 | ||
394 | case PPTP_CALL_DISCONNECT_NOTIFY: | |
926b50f9 | 395 | /* server confirms disconnect */ |
857c06da PM |
396 | cid = pptpReq->disc.callID; |
397 | DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid)); | |
926b50f9 HW |
398 | info->cstate = PPTP_CALL_NONE; |
399 | ||
400 | /* untrack this call id, unexpect GRE packets */ | |
401 | pptp_destroy_siblings(ct); | |
402 | break; | |
403 | ||
404 | case PPTP_WAN_ERROR_NOTIFY: | |
926b50f9 HW |
405 | case PPTP_ECHO_REQUEST: |
406 | case PPTP_ECHO_REPLY: | |
407 | /* I don't have to explain these ;) */ | |
408 | break; | |
409 | default: | |
87a0117a | 410 | goto invalid; |
926b50f9 HW |
411 | } |
412 | ||
337fbc41 PM |
413 | ip_nat_pptp_inbound = rcu_dereference(ip_nat_pptp_hook_inbound); |
414 | if (ip_nat_pptp_inbound) | |
415 | return ip_nat_pptp_inbound(pskb, ct, ctinfo, ctlh, pptpReq); | |
926b50f9 HW |
416 | return NF_ACCEPT; |
417 | ||
87a0117a PM |
418 | invalid: |
419 | DEBUGP("invalid %s: type=%d cid=%u pcid=%u " | |
420 | "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n", | |
421 | msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0], | |
422 | msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate, | |
423 | ntohs(info->pns_call_id), ntohs(info->pac_call_id)); | |
424 | return NF_ACCEPT; | |
926b50f9 HW |
425 | } |
426 | ||
427 | static inline int | |
428 | pptp_outbound_pkt(struct sk_buff **pskb, | |
4c651756 PM |
429 | struct PptpControlHeader *ctlh, |
430 | union pptp_ctrl_union *pptpReq, | |
431 | unsigned int reqlen, | |
926b50f9 HW |
432 | struct ip_conntrack *ct, |
433 | enum ip_conntrack_info ctinfo) | |
434 | { | |
926b50f9 | 435 | struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; |
67497205 | 436 | u_int16_t msg; |
87a0117a | 437 | __be16 cid = 0, pcid = 0; |
337fbc41 | 438 | typeof(ip_nat_pptp_hook_outbound) ip_nat_pptp_outbound; |
926b50f9 | 439 | |
926b50f9 HW |
440 | msg = ntohs(ctlh->messageType); |
441 | DEBUGP("outbound control message %s\n", pptp_msg_name[msg]); | |
442 | ||
443 | switch (msg) { | |
444 | case PPTP_START_SESSION_REQUEST: | |
445 | /* client requests for new control session */ | |
87a0117a PM |
446 | if (info->sstate != PPTP_SESSION_NONE) |
447 | goto invalid; | |
926b50f9 HW |
448 | info->sstate = PPTP_SESSION_REQUESTED; |
449 | break; | |
450 | case PPTP_STOP_SESSION_REQUEST: | |
451 | /* client requests end of control session */ | |
452 | info->sstate = PPTP_SESSION_STOPREQ; | |
453 | break; | |
454 | ||
455 | case PPTP_OUT_CALL_REQUEST: | |
926b50f9 | 456 | /* client initiating connection to server */ |
87a0117a PM |
457 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
458 | goto invalid; | |
926b50f9 HW |
459 | info->cstate = PPTP_CALL_OUT_REQ; |
460 | /* track PNS call id */ | |
857c06da PM |
461 | cid = pptpReq->ocreq.callID; |
462 | DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid)); | |
463 | info->pns_call_id = cid; | |
926b50f9 HW |
464 | break; |
465 | case PPTP_IN_CALL_REPLY: | |
926b50f9 | 466 | /* client answers incoming call */ |
87a0117a PM |
467 | if (info->cstate != PPTP_CALL_IN_REQ && |
468 | info->cstate != PPTP_CALL_IN_REP) | |
469 | goto invalid; | |
470 | ||
62fbe9c8 | 471 | cid = pptpReq->icack.callID; |
857c06da | 472 | pcid = pptpReq->icack.peersCallID; |
87a0117a PM |
473 | if (info->pac_call_id != pcid) |
474 | goto invalid; | |
62fbe9c8 PM |
475 | DEBUGP("%s, CID=%X PCID=%X\n", pptp_msg_name[msg], |
476 | ntohs(cid), ntohs(pcid)); | |
750a5842 PM |
477 | |
478 | if (pptpReq->icack.resultCode == PPTP_INCALL_ACCEPT) { | |
479 | /* part two of the three-way handshake */ | |
480 | info->cstate = PPTP_CALL_IN_REP; | |
62fbe9c8 | 481 | info->pns_call_id = cid; |
750a5842 PM |
482 | } else |
483 | info->cstate = PPTP_CALL_NONE; | |
926b50f9 HW |
484 | break; |
485 | ||
486 | case PPTP_CALL_CLEAR_REQUEST: | |
487 | /* client requests hangup of call */ | |
87a0117a PM |
488 | if (info->sstate != PPTP_SESSION_CONFIRMED) |
489 | goto invalid; | |
926b50f9 HW |
490 | /* FUTURE: iterate over all calls and check if |
491 | * call ID is valid. We don't do this without newnat, | |
492 | * because we only know about last call */ | |
493 | info->cstate = PPTP_CALL_CLEAR_REQ; | |
494 | break; | |
495 | case PPTP_SET_LINK_INFO: | |
926b50f9 HW |
496 | case PPTP_ECHO_REQUEST: |
497 | case PPTP_ECHO_REPLY: | |
498 | /* I don't have to explain these ;) */ | |
499 | break; | |
500 | default: | |
87a0117a | 501 | goto invalid; |
926b50f9 | 502 | } |
edd5a329 | 503 | |
337fbc41 PM |
504 | ip_nat_pptp_outbound = rcu_dereference(ip_nat_pptp_hook_outbound); |
505 | if (ip_nat_pptp_outbound) | |
506 | return ip_nat_pptp_outbound(pskb, ct, ctinfo, ctlh, pptpReq); | |
87a0117a | 507 | return NF_ACCEPT; |
926b50f9 | 508 | |
87a0117a PM |
509 | invalid: |
510 | DEBUGP("invalid %s: type=%d cid=%u pcid=%u " | |
511 | "cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n", | |
512 | msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0], | |
513 | msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate, | |
514 | ntohs(info->pns_call_id), ntohs(info->pac_call_id)); | |
926b50f9 HW |
515 | return NF_ACCEPT; |
516 | } | |
517 | ||
4c651756 PM |
518 | static const unsigned int pptp_msg_size[] = { |
519 | [PPTP_START_SESSION_REQUEST] = sizeof(struct PptpStartSessionRequest), | |
520 | [PPTP_START_SESSION_REPLY] = sizeof(struct PptpStartSessionReply), | |
521 | [PPTP_STOP_SESSION_REQUEST] = sizeof(struct PptpStopSessionRequest), | |
522 | [PPTP_STOP_SESSION_REPLY] = sizeof(struct PptpStopSessionReply), | |
523 | [PPTP_OUT_CALL_REQUEST] = sizeof(struct PptpOutCallRequest), | |
524 | [PPTP_OUT_CALL_REPLY] = sizeof(struct PptpOutCallReply), | |
525 | [PPTP_IN_CALL_REQUEST] = sizeof(struct PptpInCallRequest), | |
526 | [PPTP_IN_CALL_REPLY] = sizeof(struct PptpInCallReply), | |
527 | [PPTP_IN_CALL_CONNECT] = sizeof(struct PptpInCallConnected), | |
528 | [PPTP_CALL_CLEAR_REQUEST] = sizeof(struct PptpClearCallRequest), | |
529 | [PPTP_CALL_DISCONNECT_NOTIFY] = sizeof(struct PptpCallDisconnectNotify), | |
530 | [PPTP_WAN_ERROR_NOTIFY] = sizeof(struct PptpWanErrorNotify), | |
531 | [PPTP_SET_LINK_INFO] = sizeof(struct PptpSetLinkInfo), | |
532 | }; | |
926b50f9 HW |
533 | |
534 | /* track caller id inside control connection, call expect_related */ | |
edd5a329 | 535 | static int |
926b50f9 HW |
536 | conntrack_pptp_help(struct sk_buff **pskb, |
537 | struct ip_conntrack *ct, enum ip_conntrack_info ctinfo) | |
538 | ||
539 | { | |
926b50f9 HW |
540 | int dir = CTINFO2DIR(ctinfo); |
541 | struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info; | |
4c651756 PM |
542 | struct tcphdr _tcph, *tcph; |
543 | struct pptp_pkt_hdr _pptph, *pptph; | |
544 | struct PptpControlHeader _ctlh, *ctlh; | |
545 | union pptp_ctrl_union _pptpReq, *pptpReq; | |
c9bdd4b5 | 546 | unsigned int tcplen = (*pskb)->len - ip_hdrlen(*pskb); |
4c651756 | 547 | unsigned int datalen, reqlen, nexthdr_off; |
926b50f9 HW |
548 | int oldsstate, oldcstate; |
549 | int ret; | |
4c651756 | 550 | u_int16_t msg; |
926b50f9 HW |
551 | |
552 | /* don't do any tracking before tcp handshake complete */ | |
edd5a329 | 553 | if (ctinfo != IP_CT_ESTABLISHED |
926b50f9 HW |
554 | && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) { |
555 | DEBUGP("ctinfo = %u, skipping\n", ctinfo); | |
556 | return NF_ACCEPT; | |
557 | } | |
edd5a329 | 558 | |
c9bdd4b5 | 559 | nexthdr_off = ip_hdrlen(*pskb); |
926b50f9 HW |
560 | tcph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_tcph), &_tcph); |
561 | BUG_ON(!tcph); | |
562 | nexthdr_off += tcph->doff * 4; | |
e905a9ed | 563 | datalen = tcplen - tcph->doff * 4; |
926b50f9 | 564 | |
926b50f9 HW |
565 | pptph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_pptph), &_pptph); |
566 | if (!pptph) { | |
567 | DEBUGP("no full PPTP header, can't track\n"); | |
568 | return NF_ACCEPT; | |
569 | } | |
570 | nexthdr_off += sizeof(_pptph); | |
571 | datalen -= sizeof(_pptph); | |
572 | ||
573 | /* if it's not a control message we can't do anything with it */ | |
574 | if (ntohs(pptph->packetType) != PPTP_PACKET_CONTROL || | |
575 | ntohl(pptph->magicCookie) != PPTP_MAGIC_COOKIE) { | |
576 | DEBUGP("not a control packet\n"); | |
577 | return NF_ACCEPT; | |
578 | } | |
579 | ||
4c651756 PM |
580 | ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh); |
581 | if (!ctlh) | |
582 | return NF_ACCEPT; | |
583 | nexthdr_off += sizeof(_ctlh); | |
584 | datalen -= sizeof(_ctlh); | |
585 | ||
586 | reqlen = datalen; | |
587 | msg = ntohs(ctlh->messageType); | |
588 | if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg]) | |
589 | return NF_ACCEPT; | |
590 | if (reqlen > sizeof(*pptpReq)) | |
591 | reqlen = sizeof(*pptpReq); | |
592 | ||
593 | pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq); | |
594 | if (!pptpReq) | |
595 | return NF_ACCEPT; | |
596 | ||
926b50f9 HW |
597 | oldsstate = info->sstate; |
598 | oldcstate = info->cstate; | |
599 | ||
600 | spin_lock_bh(&ip_pptp_lock); | |
601 | ||
602 | /* FIXME: We just blindly assume that the control connection is always | |
603 | * established from PNS->PAC. However, RFC makes no guarantee */ | |
604 | if (dir == IP_CT_DIR_ORIGINAL) | |
605 | /* client -> server (PNS -> PAC) */ | |
4c651756 | 606 | ret = pptp_outbound_pkt(pskb, ctlh, pptpReq, reqlen, ct, |
926b50f9 HW |
607 | ctinfo); |
608 | else | |
609 | /* server -> client (PAC -> PNS) */ | |
4c651756 | 610 | ret = pptp_inbound_pkt(pskb, ctlh, pptpReq, reqlen, ct, |
926b50f9 HW |
611 | ctinfo); |
612 | DEBUGP("sstate: %d->%d, cstate: %d->%d\n", | |
613 | oldsstate, info->sstate, oldcstate, info->cstate); | |
614 | spin_unlock_bh(&ip_pptp_lock); | |
615 | ||
616 | return ret; | |
617 | } | |
618 | ||
619 | /* control protocol helper */ | |
edd5a329 | 620 | static struct ip_conntrack_helper pptp = { |
926b50f9 | 621 | .list = { NULL, NULL }, |
edd5a329 | 622 | .name = "pptp", |
926b50f9 HW |
623 | .me = THIS_MODULE, |
624 | .max_expected = 2, | |
625 | .timeout = 5 * 60, | |
edd5a329 | 626 | .tuple = { .src = { .ip = 0, |
e905a9ed | 627 | .u = { .tcp = { .port = |
edd5a329 PM |
628 | __constant_htons(PPTP_CONTROL_PORT) } } |
629 | }, | |
630 | .dst = { .ip = 0, | |
926b50f9 HW |
631 | .u = { .all = 0 }, |
632 | .protonum = IPPROTO_TCP | |
edd5a329 | 633 | } |
926b50f9 | 634 | }, |
edd5a329 PM |
635 | .mask = { .src = { .ip = 0, |
636 | .u = { .tcp = { .port = __constant_htons(0xffff) } } | |
637 | }, | |
638 | .dst = { .ip = 0, | |
926b50f9 | 639 | .u = { .all = 0 }, |
edd5a329 | 640 | .protonum = 0xff |
e905a9ed | 641 | } |
926b50f9 | 642 | }, |
4c5de695 PM |
643 | .help = conntrack_pptp_help, |
644 | .destroy = pptp_destroy_siblings, | |
926b50f9 HW |
645 | }; |
646 | ||
a7768097 | 647 | extern void ip_ct_proto_gre_fini(void); |
926b50f9 HW |
648 | extern int __init ip_ct_proto_gre_init(void); |
649 | ||
650 | /* ip_conntrack_pptp initialization */ | |
65b4b4e8 | 651 | static int __init ip_conntrack_helper_pptp_init(void) |
926b50f9 HW |
652 | { |
653 | int retcode; | |
edd5a329 | 654 | |
926b50f9 HW |
655 | retcode = ip_ct_proto_gre_init(); |
656 | if (retcode < 0) | |
657 | return retcode; | |
658 | ||
659 | DEBUGP(" registering helper\n"); | |
660 | if ((retcode = ip_conntrack_helper_register(&pptp))) { | |
661 | printk(KERN_ERR "Unable to register conntrack application " | |
662 | "helper for pptp: %d\n", retcode); | |
663 | ip_ct_proto_gre_fini(); | |
664 | return retcode; | |
665 | } | |
666 | ||
667 | printk("ip_conntrack_pptp version %s loaded\n", IP_CT_PPTP_VERSION); | |
668 | return 0; | |
669 | } | |
670 | ||
65b4b4e8 | 671 | static void __exit ip_conntrack_helper_pptp_fini(void) |
926b50f9 HW |
672 | { |
673 | ip_conntrack_helper_unregister(&pptp); | |
674 | ip_ct_proto_gre_fini(); | |
675 | printk("ip_conntrack_pptp version %s unloaded\n", IP_CT_PPTP_VERSION); | |
676 | } | |
677 | ||
65b4b4e8 AM |
678 | module_init(ip_conntrack_helper_pptp_init); |
679 | module_exit(ip_conntrack_helper_pptp_fini); | |
926b50f9 HW |
680 | |
681 | EXPORT_SYMBOL(ip_nat_pptp_hook_outbound); | |
682 | EXPORT_SYMBOL(ip_nat_pptp_hook_inbound); | |
683 | EXPORT_SYMBOL(ip_nat_pptp_hook_exp_gre); | |
684 | EXPORT_SYMBOL(ip_nat_pptp_hook_expectfn); |