Root/
1 | /* |
2 | * DCCP connection tracking protocol helper |
3 | * |
4 | * Copyright (c) 2005, 2006, 2008 Patrick McHardy <kaber@trash.net> |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify |
7 | * it under the terms of the GNU General Public License version 2 as |
8 | * published by the Free Software Foundation. |
9 | * |
10 | */ |
11 | #include <linux/kernel.h> |
12 | #include <linux/module.h> |
13 | #include <linux/init.h> |
14 | #include <linux/sysctl.h> |
15 | #include <linux/spinlock.h> |
16 | #include <linux/skbuff.h> |
17 | #include <linux/dccp.h> |
18 | #include <linux/slab.h> |
19 | |
20 | #include <net/net_namespace.h> |
21 | #include <net/netns/generic.h> |
22 | |
23 | #include <linux/netfilter/nfnetlink_conntrack.h> |
24 | #include <net/netfilter/nf_conntrack.h> |
25 | #include <net/netfilter/nf_conntrack_l4proto.h> |
26 | #include <net/netfilter/nf_conntrack_ecache.h> |
27 | #include <net/netfilter/nf_log.h> |
28 | |
29 | /* Timeouts are based on values from RFC4340: |
30 | * |
31 | * - REQUEST: |
32 | * |
33 | * 8.1.2. Client Request |
34 | * |
35 | * A client MAY give up on its DCCP-Requests after some time |
36 | * (3 minutes, for example). |
37 | * |
38 | * - RESPOND: |
39 | * |
40 | * 8.1.3. Server Response |
41 | * |
42 | * It MAY also leave the RESPOND state for CLOSED after a timeout of |
43 | * not less than 4MSL (8 minutes); |
44 | * |
45 | * - PARTOPEN: |
46 | * |
47 | * 8.1.5. Handshake Completion |
48 | * |
49 | * If the client remains in PARTOPEN for more than 4MSL (8 minutes), |
50 | * it SHOULD reset the connection with Reset Code 2, "Aborted". |
51 | * |
52 | * - OPEN: |
53 | * |
54 | * The DCCP timestamp overflows after 11.9 hours. If the connection |
55 | * stays idle this long the sequence number won't be recognized |
56 | * as valid anymore. |
57 | * |
58 | * - CLOSEREQ/CLOSING: |
59 | * |
60 | * 8.3. Termination |
61 | * |
62 | * The retransmission timer should initially be set to go off in two |
63 | * round-trip times and should back off to not less than once every |
64 | * 64 seconds ... |
65 | * |
66 | * - TIMEWAIT: |
67 | * |
68 | * 4.3. States |
69 | * |
70 | * A server or client socket remains in this state for 2MSL (4 minutes) |
71 | * after the connection has been town down, ... |
72 | */ |
73 | |
74 | #define DCCP_MSL (2 * 60 * HZ) |
75 | |
76 | static const char * const dccp_state_names[] = { |
77 | [CT_DCCP_NONE] = "NONE", |
78 | [CT_DCCP_REQUEST] = "REQUEST", |
79 | [CT_DCCP_RESPOND] = "RESPOND", |
80 | [CT_DCCP_PARTOPEN] = "PARTOPEN", |
81 | [CT_DCCP_OPEN] = "OPEN", |
82 | [CT_DCCP_CLOSEREQ] = "CLOSEREQ", |
83 | [CT_DCCP_CLOSING] = "CLOSING", |
84 | [CT_DCCP_TIMEWAIT] = "TIMEWAIT", |
85 | [CT_DCCP_IGNORE] = "IGNORE", |
86 | [CT_DCCP_INVALID] = "INVALID", |
87 | }; |
88 | |
89 | #define sNO CT_DCCP_NONE |
90 | #define sRQ CT_DCCP_REQUEST |
91 | #define sRS CT_DCCP_RESPOND |
92 | #define sPO CT_DCCP_PARTOPEN |
93 | #define sOP CT_DCCP_OPEN |
94 | #define sCR CT_DCCP_CLOSEREQ |
95 | #define sCG CT_DCCP_CLOSING |
96 | #define sTW CT_DCCP_TIMEWAIT |
97 | #define sIG CT_DCCP_IGNORE |
98 | #define sIV CT_DCCP_INVALID |
99 | |
100 | /* |
101 | * DCCP state transistion table |
102 | * |
103 | * The assumption is the same as for TCP tracking: |
104 | * |
105 | * We are the man in the middle. All the packets go through us but might |
106 | * get lost in transit to the destination. It is assumed that the destination |
107 | * can't receive segments we haven't seen. |
108 | * |
109 | * The following states exist: |
110 | * |
111 | * NONE: Initial state, expecting Request |
112 | * REQUEST: Request seen, waiting for Response from server |
113 | * RESPOND: Response from server seen, waiting for Ack from client |
114 | * PARTOPEN: Ack after Response seen, waiting for packet other than Response, |
115 | * Reset or Sync from server |
116 | * OPEN: Packet other than Response, Reset or Sync seen |
117 | * CLOSEREQ: CloseReq from server seen, expecting Close from client |
118 | * CLOSING: Close seen, expecting Reset |
119 | * TIMEWAIT: Reset seen |
120 | * IGNORE: Not determinable whether packet is valid |
121 | * |
122 | * Some states exist only on one side of the connection: REQUEST, RESPOND, |
123 | * PARTOPEN, CLOSEREQ. For the other side these states are equivalent to |
124 | * the one it was in before. |
125 | * |
126 | * Packets are marked as ignored (sIG) if we don't know if they're valid |
127 | * (for example a reincarnation of a connection we didn't notice is dead |
128 | * already) and the server may send back a connection closing Reset or a |
129 | * Response. They're also used for Sync/SyncAck packets, which we don't |
130 | * care about. |
131 | */ |
132 | static const u_int8_t |
133 | dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = { |
134 | [CT_DCCP_ROLE_CLIENT] = { |
135 | [DCCP_PKT_REQUEST] = { |
136 | /* |
137 | * sNO -> sRQ Regular Request |
138 | * sRQ -> sRQ Retransmitted Request or reincarnation |
139 | * sRS -> sRS Retransmitted Request (apparently Response |
140 | * got lost after we saw it) or reincarnation |
141 | * sPO -> sIG Ignore, conntrack might be out of sync |
142 | * sOP -> sIG Ignore, conntrack might be out of sync |
143 | * sCR -> sIG Ignore, conntrack might be out of sync |
144 | * sCG -> sIG Ignore, conntrack might be out of sync |
145 | * sTW -> sRQ Reincarnation |
146 | * |
147 | * sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */ |
148 | sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ, |
149 | }, |
150 | [DCCP_PKT_RESPONSE] = { |
151 | /* |
152 | * sNO -> sIV Invalid |
153 | * sRQ -> sIG Ignore, might be response to ignored Request |
154 | * sRS -> sIG Ignore, might be response to ignored Request |
155 | * sPO -> sIG Ignore, might be response to ignored Request |
156 | * sOP -> sIG Ignore, might be response to ignored Request |
157 | * sCR -> sIG Ignore, might be response to ignored Request |
158 | * sCG -> sIG Ignore, might be response to ignored Request |
159 | * sTW -> sIV Invalid, reincarnation in reverse direction |
160 | * goes through sRQ |
161 | * |
162 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
163 | sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV, |
164 | }, |
165 | [DCCP_PKT_ACK] = { |
166 | /* |
167 | * sNO -> sIV No connection |
168 | * sRQ -> sIV No connection |
169 | * sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.) |
170 | * sPO -> sPO Retransmitted Ack for Response, remain in PARTOPEN |
171 | * sOP -> sOP Regular ACK, remain in OPEN |
172 | * sCR -> sCR Ack in CLOSEREQ MAY be processed (8.3.) |
173 | * sCG -> sCG Ack in CLOSING MAY be processed (8.3.) |
174 | * sTW -> sIV |
175 | * |
176 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
177 | sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV |
178 | }, |
179 | [DCCP_PKT_DATA] = { |
180 | /* |
181 | * sNO -> sIV No connection |
182 | * sRQ -> sIV No connection |
183 | * sRS -> sIV No connection |
184 | * sPO -> sIV MUST use DataAck in PARTOPEN state (8.1.5.) |
185 | * sOP -> sOP Regular Data packet |
186 | * sCR -> sCR Data in CLOSEREQ MAY be processed (8.3.) |
187 | * sCG -> sCG Data in CLOSING MAY be processed (8.3.) |
188 | * sTW -> sIV |
189 | * |
190 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
191 | sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV, |
192 | }, |
193 | [DCCP_PKT_DATAACK] = { |
194 | /* |
195 | * sNO -> sIV No connection |
196 | * sRQ -> sIV No connection |
197 | * sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.) |
198 | * sPO -> sPO Remain in PARTOPEN state |
199 | * sOP -> sOP Regular DataAck packet in OPEN state |
200 | * sCR -> sCR DataAck in CLOSEREQ MAY be processed (8.3.) |
201 | * sCG -> sCG DataAck in CLOSING MAY be processed (8.3.) |
202 | * sTW -> sIV |
203 | * |
204 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
205 | sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV |
206 | }, |
207 | [DCCP_PKT_CLOSEREQ] = { |
208 | /* |
209 | * CLOSEREQ may only be sent by the server. |
210 | * |
211 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
212 | sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV |
213 | }, |
214 | [DCCP_PKT_CLOSE] = { |
215 | /* |
216 | * sNO -> sIV No connection |
217 | * sRQ -> sIV No connection |
218 | * sRS -> sIV No connection |
219 | * sPO -> sCG Client-initiated close |
220 | * sOP -> sCG Client-initiated close |
221 | * sCR -> sCG Close in response to CloseReq (8.3.) |
222 | * sCG -> sCG Retransmit |
223 | * sTW -> sIV Late retransmit, already in TIME_WAIT |
224 | * |
225 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
226 | sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV |
227 | }, |
228 | [DCCP_PKT_RESET] = { |
229 | /* |
230 | * sNO -> sIV No connection |
231 | * sRQ -> sTW Sync received or timeout, SHOULD send Reset (8.1.1.) |
232 | * sRS -> sTW Response received without Request |
233 | * sPO -> sTW Timeout, SHOULD send Reset (8.1.5.) |
234 | * sOP -> sTW Connection reset |
235 | * sCR -> sTW Connection reset |
236 | * sCG -> sTW Connection reset |
237 | * sTW -> sIG Ignore (don't refresh timer) |
238 | * |
239 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
240 | sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG |
241 | }, |
242 | [DCCP_PKT_SYNC] = { |
243 | /* |
244 | * We currently ignore Sync packets |
245 | * |
246 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
247 | sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
248 | }, |
249 | [DCCP_PKT_SYNCACK] = { |
250 | /* |
251 | * We currently ignore SyncAck packets |
252 | * |
253 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
254 | sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
255 | }, |
256 | }, |
257 | [CT_DCCP_ROLE_SERVER] = { |
258 | [DCCP_PKT_REQUEST] = { |
259 | /* |
260 | * sNO -> sIV Invalid |
261 | * sRQ -> sIG Ignore, conntrack might be out of sync |
262 | * sRS -> sIG Ignore, conntrack might be out of sync |
263 | * sPO -> sIG Ignore, conntrack might be out of sync |
264 | * sOP -> sIG Ignore, conntrack might be out of sync |
265 | * sCR -> sIG Ignore, conntrack might be out of sync |
266 | * sCG -> sIG Ignore, conntrack might be out of sync |
267 | * sTW -> sRQ Reincarnation, must reverse roles |
268 | * |
269 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
270 | sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ |
271 | }, |
272 | [DCCP_PKT_RESPONSE] = { |
273 | /* |
274 | * sNO -> sIV Response without Request |
275 | * sRQ -> sRS Response to clients Request |
276 | * sRS -> sRS Retransmitted Response (8.1.3. SHOULD NOT) |
277 | * sPO -> sIG Response to an ignored Request or late retransmit |
278 | * sOP -> sIG Ignore, might be response to ignored Request |
279 | * sCR -> sIG Ignore, might be response to ignored Request |
280 | * sCG -> sIG Ignore, might be response to ignored Request |
281 | * sTW -> sIV Invalid, Request from client in sTW moves to sRQ |
282 | * |
283 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
284 | sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV |
285 | }, |
286 | [DCCP_PKT_ACK] = { |
287 | /* |
288 | * sNO -> sIV No connection |
289 | * sRQ -> sIV No connection |
290 | * sRS -> sIV No connection |
291 | * sPO -> sOP Enter OPEN state (8.1.5.) |
292 | * sOP -> sOP Regular Ack in OPEN state |
293 | * sCR -> sIV Waiting for Close from client |
294 | * sCG -> sCG Ack in CLOSING MAY be processed (8.3.) |
295 | * sTW -> sIV |
296 | * |
297 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
298 | sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV |
299 | }, |
300 | [DCCP_PKT_DATA] = { |
301 | /* |
302 | * sNO -> sIV No connection |
303 | * sRQ -> sIV No connection |
304 | * sRS -> sIV No connection |
305 | * sPO -> sOP Enter OPEN state (8.1.5.) |
306 | * sOP -> sOP Regular Data packet in OPEN state |
307 | * sCR -> sIV Waiting for Close from client |
308 | * sCG -> sCG Data in CLOSING MAY be processed (8.3.) |
309 | * sTW -> sIV |
310 | * |
311 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
312 | sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV |
313 | }, |
314 | [DCCP_PKT_DATAACK] = { |
315 | /* |
316 | * sNO -> sIV No connection |
317 | * sRQ -> sIV No connection |
318 | * sRS -> sIV No connection |
319 | * sPO -> sOP Enter OPEN state (8.1.5.) |
320 | * sOP -> sOP Regular DataAck in OPEN state |
321 | * sCR -> sIV Waiting for Close from client |
322 | * sCG -> sCG Data in CLOSING MAY be processed (8.3.) |
323 | * sTW -> sIV |
324 | * |
325 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
326 | sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV |
327 | }, |
328 | [DCCP_PKT_CLOSEREQ] = { |
329 | /* |
330 | * sNO -> sIV No connection |
331 | * sRQ -> sIV No connection |
332 | * sRS -> sIV No connection |
333 | * sPO -> sOP -> sCR Move directly to CLOSEREQ (8.1.5.) |
334 | * sOP -> sCR CloseReq in OPEN state |
335 | * sCR -> sCR Retransmit |
336 | * sCG -> sCR Simultaneous close, client sends another Close |
337 | * sTW -> sIV Already closed |
338 | * |
339 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
340 | sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV |
341 | }, |
342 | [DCCP_PKT_CLOSE] = { |
343 | /* |
344 | * sNO -> sIV No connection |
345 | * sRQ -> sIV No connection |
346 | * sRS -> sIV No connection |
347 | * sPO -> sOP -> sCG Move direcly to CLOSING |
348 | * sOP -> sCG Move to CLOSING |
349 | * sCR -> sIV Close after CloseReq is invalid |
350 | * sCG -> sCG Retransmit |
351 | * sTW -> sIV Already closed |
352 | * |
353 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
354 | sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV |
355 | }, |
356 | [DCCP_PKT_RESET] = { |
357 | /* |
358 | * sNO -> sIV No connection |
359 | * sRQ -> sTW Reset in response to Request |
360 | * sRS -> sTW Timeout, SHOULD send Reset (8.1.3.) |
361 | * sPO -> sTW Timeout, SHOULD send Reset (8.1.3.) |
362 | * sOP -> sTW |
363 | * sCR -> sTW |
364 | * sCG -> sTW |
365 | * sTW -> sIG Ignore (don't refresh timer) |
366 | * |
367 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */ |
368 | sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG |
369 | }, |
370 | [DCCP_PKT_SYNC] = { |
371 | /* |
372 | * We currently ignore Sync packets |
373 | * |
374 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
375 | sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
376 | }, |
377 | [DCCP_PKT_SYNCACK] = { |
378 | /* |
379 | * We currently ignore SyncAck packets |
380 | * |
381 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ |
382 | sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
383 | }, |
384 | }, |
385 | }; |
386 | |
387 | /* this module per-net specifics */ |
388 | static int dccp_net_id __read_mostly; |
389 | struct dccp_net { |
390 | int dccp_loose; |
391 | unsigned int dccp_timeout[CT_DCCP_MAX + 1]; |
392 | #ifdef CONFIG_SYSCTL |
393 | struct ctl_table_header *sysctl_header; |
394 | struct ctl_table *sysctl_table; |
395 | #endif |
396 | }; |
397 | |
398 | static inline struct dccp_net *dccp_pernet(struct net *net) |
399 | { |
400 | return net_generic(net, dccp_net_id); |
401 | } |
402 | |
403 | static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff, |
404 | struct nf_conntrack_tuple *tuple) |
405 | { |
406 | struct dccp_hdr _hdr, *dh; |
407 | |
408 | dh = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); |
409 | if (dh == NULL) |
410 | return false; |
411 | |
412 | tuple->src.u.dccp.port = dh->dccph_sport; |
413 | tuple->dst.u.dccp.port = dh->dccph_dport; |
414 | return true; |
415 | } |
416 | |
417 | static bool dccp_invert_tuple(struct nf_conntrack_tuple *inv, |
418 | const struct nf_conntrack_tuple *tuple) |
419 | { |
420 | inv->src.u.dccp.port = tuple->dst.u.dccp.port; |
421 | inv->dst.u.dccp.port = tuple->src.u.dccp.port; |
422 | return true; |
423 | } |
424 | |
425 | static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb, |
426 | unsigned int dataoff) |
427 | { |
428 | struct net *net = nf_ct_net(ct); |
429 | struct dccp_net *dn; |
430 | struct dccp_hdr _dh, *dh; |
431 | const char *msg; |
432 | u_int8_t state; |
433 | |
434 | dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh); |
435 | BUG_ON(dh == NULL); |
436 | |
437 | state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE]; |
438 | switch (state) { |
439 | default: |
440 | dn = dccp_pernet(net); |
441 | if (dn->dccp_loose == 0) { |
442 | msg = "nf_ct_dccp: not picking up existing connection "; |
443 | goto out_invalid; |
444 | } |
445 | case CT_DCCP_REQUEST: |
446 | break; |
447 | case CT_DCCP_INVALID: |
448 | msg = "nf_ct_dccp: invalid state transition "; |
449 | goto out_invalid; |
450 | } |
451 | |
452 | ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT; |
453 | ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER; |
454 | ct->proto.dccp.state = CT_DCCP_NONE; |
455 | return true; |
456 | |
457 | out_invalid: |
458 | if (LOG_INVALID(net, IPPROTO_DCCP)) |
459 | nf_log_packet(nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL, msg); |
460 | return false; |
461 | } |
462 | |
463 | static u64 dccp_ack_seq(const struct dccp_hdr *dh) |
464 | { |
465 | const struct dccp_hdr_ack_bits *dhack; |
466 | |
467 | dhack = (void *)dh + __dccp_basic_hdr_len(dh); |
468 | return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + |
469 | ntohl(dhack->dccph_ack_nr_low); |
470 | } |
471 | |
472 | static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb, |
473 | unsigned int dataoff, enum ip_conntrack_info ctinfo, |
474 | u_int8_t pf, unsigned int hooknum) |
475 | { |
476 | struct net *net = nf_ct_net(ct); |
477 | struct dccp_net *dn; |
478 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
479 | struct dccp_hdr _dh, *dh; |
480 | u_int8_t type, old_state, new_state; |
481 | enum ct_dccp_roles role; |
482 | |
483 | dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh); |
484 | BUG_ON(dh == NULL); |
485 | type = dh->dccph_type; |
486 | |
487 | if (type == DCCP_PKT_RESET && |
488 | !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { |
489 | /* Tear down connection immediately if only reply is a RESET */ |
490 | nf_ct_kill_acct(ct, ctinfo, skb); |
491 | return NF_ACCEPT; |
492 | } |
493 | |
494 | spin_lock_bh(&ct->lock); |
495 | |
496 | role = ct->proto.dccp.role[dir]; |
497 | old_state = ct->proto.dccp.state; |
498 | new_state = dccp_state_table[role][type][old_state]; |
499 | |
500 | switch (new_state) { |
501 | case CT_DCCP_REQUEST: |
502 | if (old_state == CT_DCCP_TIMEWAIT && |
503 | role == CT_DCCP_ROLE_SERVER) { |
504 | /* Reincarnation in the reverse direction: reopen and |
505 | * reverse client/server roles. */ |
506 | ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT; |
507 | ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER; |
508 | } |
509 | break; |
510 | case CT_DCCP_RESPOND: |
511 | if (old_state == CT_DCCP_REQUEST) |
512 | ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh); |
513 | break; |
514 | case CT_DCCP_PARTOPEN: |
515 | if (old_state == CT_DCCP_RESPOND && |
516 | type == DCCP_PKT_ACK && |
517 | dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq) |
518 | set_bit(IPS_ASSURED_BIT, &ct->status); |
519 | break; |
520 | case CT_DCCP_IGNORE: |
521 | /* |
522 | * Connection tracking might be out of sync, so we ignore |
523 | * packets that might establish a new connection and resync |
524 | * if the server responds with a valid Response. |
525 | */ |
526 | if (ct->proto.dccp.last_dir == !dir && |
527 | ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST && |
528 | type == DCCP_PKT_RESPONSE) { |
529 | ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT; |
530 | ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER; |
531 | ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh); |
532 | new_state = CT_DCCP_RESPOND; |
533 | break; |
534 | } |
535 | ct->proto.dccp.last_dir = dir; |
536 | ct->proto.dccp.last_pkt = type; |
537 | |
538 | spin_unlock_bh(&ct->lock); |
539 | if (LOG_INVALID(net, IPPROTO_DCCP)) |
540 | nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
541 | "nf_ct_dccp: invalid packet ignored "); |
542 | return NF_ACCEPT; |
543 | case CT_DCCP_INVALID: |
544 | spin_unlock_bh(&ct->lock); |
545 | if (LOG_INVALID(net, IPPROTO_DCCP)) |
546 | nf_log_packet(pf, 0, skb, NULL, NULL, NULL, |
547 | "nf_ct_dccp: invalid state transition "); |
548 | return -NF_ACCEPT; |
549 | } |
550 | |
551 | ct->proto.dccp.last_dir = dir; |
552 | ct->proto.dccp.last_pkt = type; |
553 | ct->proto.dccp.state = new_state; |
554 | spin_unlock_bh(&ct->lock); |
555 | |
556 | if (new_state != old_state) |
557 | nf_conntrack_event_cache(IPCT_PROTOINFO, ct); |
558 | |
559 | dn = dccp_pernet(net); |
560 | nf_ct_refresh_acct(ct, ctinfo, skb, dn->dccp_timeout[new_state]); |
561 | |
562 | return NF_ACCEPT; |
563 | } |
564 | |
565 | static int dccp_error(struct net *net, struct nf_conn *tmpl, |
566 | struct sk_buff *skb, unsigned int dataoff, |
567 | enum ip_conntrack_info *ctinfo, |
568 | u_int8_t pf, unsigned int hooknum) |
569 | { |
570 | struct dccp_hdr _dh, *dh; |
571 | unsigned int dccp_len = skb->len - dataoff; |
572 | unsigned int cscov; |
573 | const char *msg; |
574 | |
575 | dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh); |
576 | if (dh == NULL) { |
577 | msg = "nf_ct_dccp: short packet "; |
578 | goto out_invalid; |
579 | } |
580 | |
581 | if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) || |
582 | dh->dccph_doff * 4 > dccp_len) { |
583 | msg = "nf_ct_dccp: truncated/malformed packet "; |
584 | goto out_invalid; |
585 | } |
586 | |
587 | cscov = dccp_len; |
588 | if (dh->dccph_cscov) { |
589 | cscov = (dh->dccph_cscov - 1) * 4; |
590 | if (cscov > dccp_len) { |
591 | msg = "nf_ct_dccp: bad checksum coverage "; |
592 | goto out_invalid; |
593 | } |
594 | } |
595 | |
596 | if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING && |
597 | nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP, |
598 | pf)) { |
599 | msg = "nf_ct_dccp: bad checksum "; |
600 | goto out_invalid; |
601 | } |
602 | |
603 | if (dh->dccph_type >= DCCP_PKT_INVALID) { |
604 | msg = "nf_ct_dccp: reserved packet type "; |
605 | goto out_invalid; |
606 | } |
607 | |
608 | return NF_ACCEPT; |
609 | |
610 | out_invalid: |
611 | if (LOG_INVALID(net, IPPROTO_DCCP)) |
612 | nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg); |
613 | return -NF_ACCEPT; |
614 | } |
615 | |
616 | static int dccp_print_tuple(struct seq_file *s, |
617 | const struct nf_conntrack_tuple *tuple) |
618 | { |
619 | return seq_printf(s, "sport=%hu dport=%hu ", |
620 | ntohs(tuple->src.u.dccp.port), |
621 | ntohs(tuple->dst.u.dccp.port)); |
622 | } |
623 | |
624 | static int dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct) |
625 | { |
626 | return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]); |
627 | } |
628 | |
629 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
630 | static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla, |
631 | struct nf_conn *ct) |
632 | { |
633 | struct nlattr *nest_parms; |
634 | |
635 | spin_lock_bh(&ct->lock); |
636 | nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED); |
637 | if (!nest_parms) |
638 | goto nla_put_failure; |
639 | NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state); |
640 | NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_ROLE, |
641 | ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]); |
642 | NLA_PUT_BE64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ, |
643 | cpu_to_be64(ct->proto.dccp.handshake_seq)); |
644 | nla_nest_end(skb, nest_parms); |
645 | spin_unlock_bh(&ct->lock); |
646 | return 0; |
647 | |
648 | nla_put_failure: |
649 | spin_unlock_bh(&ct->lock); |
650 | return -1; |
651 | } |
652 | |
653 | static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = { |
654 | [CTA_PROTOINFO_DCCP_STATE] = { .type = NLA_U8 }, |
655 | [CTA_PROTOINFO_DCCP_ROLE] = { .type = NLA_U8 }, |
656 | [CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 }, |
657 | }; |
658 | |
659 | static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct) |
660 | { |
661 | struct nlattr *attr = cda[CTA_PROTOINFO_DCCP]; |
662 | struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1]; |
663 | int err; |
664 | |
665 | if (!attr) |
666 | return 0; |
667 | |
668 | err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr, |
669 | dccp_nla_policy); |
670 | if (err < 0) |
671 | return err; |
672 | |
673 | if (!tb[CTA_PROTOINFO_DCCP_STATE] || |
674 | !tb[CTA_PROTOINFO_DCCP_ROLE] || |
675 | nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX || |
676 | nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) { |
677 | return -EINVAL; |
678 | } |
679 | |
680 | spin_lock_bh(&ct->lock); |
681 | ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]); |
682 | if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) { |
683 | ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT; |
684 | ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER; |
685 | } else { |
686 | ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER; |
687 | ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT; |
688 | } |
689 | if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) { |
690 | ct->proto.dccp.handshake_seq = |
691 | be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ])); |
692 | } |
693 | spin_unlock_bh(&ct->lock); |
694 | return 0; |
695 | } |
696 | |
697 | static int dccp_nlattr_size(void) |
698 | { |
699 | return nla_total_size(0) /* CTA_PROTOINFO_DCCP */ |
700 | + nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1); |
701 | } |
702 | #endif |
703 | |
704 | #ifdef CONFIG_SYSCTL |
705 | /* template, data assigned later */ |
706 | static struct ctl_table dccp_sysctl_table[] = { |
707 | { |
708 | .procname = "nf_conntrack_dccp_timeout_request", |
709 | .maxlen = sizeof(unsigned int), |
710 | .mode = 0644, |
711 | .proc_handler = proc_dointvec_jiffies, |
712 | }, |
713 | { |
714 | .procname = "nf_conntrack_dccp_timeout_respond", |
715 | .maxlen = sizeof(unsigned int), |
716 | .mode = 0644, |
717 | .proc_handler = proc_dointvec_jiffies, |
718 | }, |
719 | { |
720 | .procname = "nf_conntrack_dccp_timeout_partopen", |
721 | .maxlen = sizeof(unsigned int), |
722 | .mode = 0644, |
723 | .proc_handler = proc_dointvec_jiffies, |
724 | }, |
725 | { |
726 | .procname = "nf_conntrack_dccp_timeout_open", |
727 | .maxlen = sizeof(unsigned int), |
728 | .mode = 0644, |
729 | .proc_handler = proc_dointvec_jiffies, |
730 | }, |
731 | { |
732 | .procname = "nf_conntrack_dccp_timeout_closereq", |
733 | .maxlen = sizeof(unsigned int), |
734 | .mode = 0644, |
735 | .proc_handler = proc_dointvec_jiffies, |
736 | }, |
737 | { |
738 | .procname = "nf_conntrack_dccp_timeout_closing", |
739 | .maxlen = sizeof(unsigned int), |
740 | .mode = 0644, |
741 | .proc_handler = proc_dointvec_jiffies, |
742 | }, |
743 | { |
744 | .procname = "nf_conntrack_dccp_timeout_timewait", |
745 | .maxlen = sizeof(unsigned int), |
746 | .mode = 0644, |
747 | .proc_handler = proc_dointvec_jiffies, |
748 | }, |
749 | { |
750 | .procname = "nf_conntrack_dccp_loose", |
751 | .maxlen = sizeof(int), |
752 | .mode = 0644, |
753 | .proc_handler = proc_dointvec, |
754 | }, |
755 | { } |
756 | }; |
757 | #endif /* CONFIG_SYSCTL */ |
758 | |
759 | static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = { |
760 | .l3proto = AF_INET, |
761 | .l4proto = IPPROTO_DCCP, |
762 | .name = "dccp", |
763 | .pkt_to_tuple = dccp_pkt_to_tuple, |
764 | .invert_tuple = dccp_invert_tuple, |
765 | .new = dccp_new, |
766 | .packet = dccp_packet, |
767 | .error = dccp_error, |
768 | .print_tuple = dccp_print_tuple, |
769 | .print_conntrack = dccp_print_conntrack, |
770 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
771 | .to_nlattr = dccp_to_nlattr, |
772 | .nlattr_size = dccp_nlattr_size, |
773 | .from_nlattr = nlattr_to_dccp, |
774 | .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, |
775 | .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, |
776 | .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, |
777 | .nla_policy = nf_ct_port_nla_policy, |
778 | #endif |
779 | }; |
780 | |
781 | static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = { |
782 | .l3proto = AF_INET6, |
783 | .l4proto = IPPROTO_DCCP, |
784 | .name = "dccp", |
785 | .pkt_to_tuple = dccp_pkt_to_tuple, |
786 | .invert_tuple = dccp_invert_tuple, |
787 | .new = dccp_new, |
788 | .packet = dccp_packet, |
789 | .error = dccp_error, |
790 | .print_tuple = dccp_print_tuple, |
791 | .print_conntrack = dccp_print_conntrack, |
792 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
793 | .to_nlattr = dccp_to_nlattr, |
794 | .nlattr_size = dccp_nlattr_size, |
795 | .from_nlattr = nlattr_to_dccp, |
796 | .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, |
797 | .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, |
798 | .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, |
799 | .nla_policy = nf_ct_port_nla_policy, |
800 | #endif |
801 | }; |
802 | |
803 | static __net_init int dccp_net_init(struct net *net) |
804 | { |
805 | struct dccp_net *dn = dccp_pernet(net); |
806 | |
807 | /* default values */ |
808 | dn->dccp_loose = 1; |
809 | dn->dccp_timeout[CT_DCCP_REQUEST] = 2 * DCCP_MSL; |
810 | dn->dccp_timeout[CT_DCCP_RESPOND] = 4 * DCCP_MSL; |
811 | dn->dccp_timeout[CT_DCCP_PARTOPEN] = 4 * DCCP_MSL; |
812 | dn->dccp_timeout[CT_DCCP_OPEN] = 12 * 3600 * HZ; |
813 | dn->dccp_timeout[CT_DCCP_CLOSEREQ] = 64 * HZ; |
814 | dn->dccp_timeout[CT_DCCP_CLOSING] = 64 * HZ; |
815 | dn->dccp_timeout[CT_DCCP_TIMEWAIT] = 2 * DCCP_MSL; |
816 | |
817 | #ifdef CONFIG_SYSCTL |
818 | dn->sysctl_table = kmemdup(dccp_sysctl_table, |
819 | sizeof(dccp_sysctl_table), GFP_KERNEL); |
820 | if (!dn->sysctl_table) |
821 | return -ENOMEM; |
822 | |
823 | dn->sysctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST]; |
824 | dn->sysctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND]; |
825 | dn->sysctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN]; |
826 | dn->sysctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN]; |
827 | dn->sysctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ]; |
828 | dn->sysctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING]; |
829 | dn->sysctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT]; |
830 | dn->sysctl_table[7].data = &dn->dccp_loose; |
831 | |
832 | dn->sysctl_header = register_net_sysctl_table(net, |
833 | nf_net_netfilter_sysctl_path, dn->sysctl_table); |
834 | if (!dn->sysctl_header) { |
835 | kfree(dn->sysctl_table); |
836 | return -ENOMEM; |
837 | } |
838 | #endif |
839 | |
840 | return 0; |
841 | } |
842 | |
843 | static __net_exit void dccp_net_exit(struct net *net) |
844 | { |
845 | struct dccp_net *dn = dccp_pernet(net); |
846 | #ifdef CONFIG_SYSCTL |
847 | unregister_net_sysctl_table(dn->sysctl_header); |
848 | kfree(dn->sysctl_table); |
849 | #endif |
850 | } |
851 | |
852 | static struct pernet_operations dccp_net_ops = { |
853 | .init = dccp_net_init, |
854 | .exit = dccp_net_exit, |
855 | .id = &dccp_net_id, |
856 | .size = sizeof(struct dccp_net), |
857 | }; |
858 | |
859 | static int __init nf_conntrack_proto_dccp_init(void) |
860 | { |
861 | int err; |
862 | |
863 | err = register_pernet_subsys(&dccp_net_ops); |
864 | if (err < 0) |
865 | goto err1; |
866 | |
867 | err = nf_conntrack_l4proto_register(&dccp_proto4); |
868 | if (err < 0) |
869 | goto err2; |
870 | |
871 | err = nf_conntrack_l4proto_register(&dccp_proto6); |
872 | if (err < 0) |
873 | goto err3; |
874 | return 0; |
875 | |
876 | err3: |
877 | nf_conntrack_l4proto_unregister(&dccp_proto4); |
878 | err2: |
879 | unregister_pernet_subsys(&dccp_net_ops); |
880 | err1: |
881 | return err; |
882 | } |
883 | |
884 | static void __exit nf_conntrack_proto_dccp_fini(void) |
885 | { |
886 | unregister_pernet_subsys(&dccp_net_ops); |
887 | nf_conntrack_l4proto_unregister(&dccp_proto6); |
888 | nf_conntrack_l4proto_unregister(&dccp_proto4); |
889 | } |
890 | |
891 | module_init(nf_conntrack_proto_dccp_init); |
892 | module_exit(nf_conntrack_proto_dccp_fini); |
893 | |
894 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
895 | MODULE_DESCRIPTION("DCCP connection tracking protocol helper"); |
896 | MODULE_LICENSE("GPL"); |
897 |
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