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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
2bc78049 PM |
2 | /* |
3 | * DCCP connection tracking protocol helper | |
4 | * | |
5 | * Copyright (c) 2005, 2006, 2008 Patrick McHardy <kaber@trash.net> | |
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6 | */ |
7 | #include <linux/kernel.h> | |
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8 | #include <linux/init.h> |
9 | #include <linux/sysctl.h> | |
10 | #include <linux/spinlock.h> | |
11 | #include <linux/skbuff.h> | |
12 | #include <linux/dccp.h> | |
5a0e3ad6 | 13 | #include <linux/slab.h> |
2bc78049 | 14 | |
1546000f CG |
15 | #include <net/net_namespace.h> |
16 | #include <net/netns/generic.h> | |
17 | ||
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18 | #include <linux/netfilter/nfnetlink_conntrack.h> |
19 | #include <net/netfilter/nf_conntrack.h> | |
20 | #include <net/netfilter/nf_conntrack_l4proto.h> | |
b38b1f61 | 21 | #include <net/netfilter/nf_conntrack_ecache.h> |
c779e849 | 22 | #include <net/netfilter/nf_conntrack_timeout.h> |
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23 | #include <net/netfilter/nf_log.h> |
24 | ||
2bc78049 PM |
25 | /* Timeouts are based on values from RFC4340: |
26 | * | |
27 | * - REQUEST: | |
28 | * | |
29 | * 8.1.2. Client Request | |
30 | * | |
31 | * A client MAY give up on its DCCP-Requests after some time | |
32 | * (3 minutes, for example). | |
33 | * | |
34 | * - RESPOND: | |
35 | * | |
36 | * 8.1.3. Server Response | |
37 | * | |
38 | * It MAY also leave the RESPOND state for CLOSED after a timeout of | |
39 | * not less than 4MSL (8 minutes); | |
40 | * | |
41 | * - PARTOPEN: | |
42 | * | |
43 | * 8.1.5. Handshake Completion | |
44 | * | |
45 | * If the client remains in PARTOPEN for more than 4MSL (8 minutes), | |
46 | * it SHOULD reset the connection with Reset Code 2, "Aborted". | |
47 | * | |
48 | * - OPEN: | |
49 | * | |
50 | * The DCCP timestamp overflows after 11.9 hours. If the connection | |
51 | * stays idle this long the sequence number won't be recognized | |
52 | * as valid anymore. | |
53 | * | |
54 | * - CLOSEREQ/CLOSING: | |
55 | * | |
56 | * 8.3. Termination | |
57 | * | |
58 | * The retransmission timer should initially be set to go off in two | |
59 | * round-trip times and should back off to not less than once every | |
60 | * 64 seconds ... | |
61 | * | |
62 | * - TIMEWAIT: | |
63 | * | |
64 | * 4.3. States | |
65 | * | |
66 | * A server or client socket remains in this state for 2MSL (4 minutes) | |
67 | * after the connection has been town down, ... | |
68 | */ | |
69 | ||
70 | #define DCCP_MSL (2 * 60 * HZ) | |
71 | ||
a927d777 | 72 | #ifdef CONFIG_NF_CONNTRACK_PROCFS |
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73 | static const char * const dccp_state_names[] = { |
74 | [CT_DCCP_NONE] = "NONE", | |
75 | [CT_DCCP_REQUEST] = "REQUEST", | |
76 | [CT_DCCP_RESPOND] = "RESPOND", | |
77 | [CT_DCCP_PARTOPEN] = "PARTOPEN", | |
78 | [CT_DCCP_OPEN] = "OPEN", | |
79 | [CT_DCCP_CLOSEREQ] = "CLOSEREQ", | |
80 | [CT_DCCP_CLOSING] = "CLOSING", | |
81 | [CT_DCCP_TIMEWAIT] = "TIMEWAIT", | |
82 | [CT_DCCP_IGNORE] = "IGNORE", | |
83 | [CT_DCCP_INVALID] = "INVALID", | |
84 | }; | |
a927d777 | 85 | #endif |
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86 | |
87 | #define sNO CT_DCCP_NONE | |
88 | #define sRQ CT_DCCP_REQUEST | |
89 | #define sRS CT_DCCP_RESPOND | |
90 | #define sPO CT_DCCP_PARTOPEN | |
91 | #define sOP CT_DCCP_OPEN | |
92 | #define sCR CT_DCCP_CLOSEREQ | |
93 | #define sCG CT_DCCP_CLOSING | |
94 | #define sTW CT_DCCP_TIMEWAIT | |
95 | #define sIG CT_DCCP_IGNORE | |
96 | #define sIV CT_DCCP_INVALID | |
97 | ||
98 | /* | |
25985edc | 99 | * DCCP state transition table |
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100 | * |
101 | * The assumption is the same as for TCP tracking: | |
102 | * | |
103 | * We are the man in the middle. All the packets go through us but might | |
104 | * get lost in transit to the destination. It is assumed that the destination | |
105 | * can't receive segments we haven't seen. | |
106 | * | |
107 | * The following states exist: | |
108 | * | |
109 | * NONE: Initial state, expecting Request | |
110 | * REQUEST: Request seen, waiting for Response from server | |
111 | * RESPOND: Response from server seen, waiting for Ack from client | |
112 | * PARTOPEN: Ack after Response seen, waiting for packet other than Response, | |
113 | * Reset or Sync from server | |
114 | * OPEN: Packet other than Response, Reset or Sync seen | |
115 | * CLOSEREQ: CloseReq from server seen, expecting Close from client | |
116 | * CLOSING: Close seen, expecting Reset | |
117 | * TIMEWAIT: Reset seen | |
118 | * IGNORE: Not determinable whether packet is valid | |
119 | * | |
120 | * Some states exist only on one side of the connection: REQUEST, RESPOND, | |
121 | * PARTOPEN, CLOSEREQ. For the other side these states are equivalent to | |
122 | * the one it was in before. | |
123 | * | |
124 | * Packets are marked as ignored (sIG) if we don't know if they're valid | |
125 | * (for example a reincarnation of a connection we didn't notice is dead | |
126 | * already) and the server may send back a connection closing Reset or a | |
127 | * Response. They're also used for Sync/SyncAck packets, which we don't | |
128 | * care about. | |
129 | */ | |
130 | static const u_int8_t | |
131 | dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = { | |
132 | [CT_DCCP_ROLE_CLIENT] = { | |
133 | [DCCP_PKT_REQUEST] = { | |
134 | /* | |
135 | * sNO -> sRQ Regular Request | |
136 | * sRQ -> sRQ Retransmitted Request or reincarnation | |
137 | * sRS -> sRS Retransmitted Request (apparently Response | |
138 | * got lost after we saw it) or reincarnation | |
139 | * sPO -> sIG Ignore, conntrack might be out of sync | |
140 | * sOP -> sIG Ignore, conntrack might be out of sync | |
141 | * sCR -> sIG Ignore, conntrack might be out of sync | |
142 | * sCG -> sIG Ignore, conntrack might be out of sync | |
143 | * sTW -> sRQ Reincarnation | |
144 | * | |
145 | * sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */ | |
146 | sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ, | |
147 | }, | |
148 | [DCCP_PKT_RESPONSE] = { | |
149 | /* | |
150 | * sNO -> sIV Invalid | |
151 | * sRQ -> sIG Ignore, might be response to ignored Request | |
152 | * sRS -> sIG Ignore, might be response to ignored Request | |
153 | * sPO -> sIG Ignore, might be response to ignored Request | |
154 | * sOP -> sIG Ignore, might be response to ignored Request | |
155 | * sCR -> sIG Ignore, might be response to ignored Request | |
156 | * sCG -> sIG Ignore, might be response to ignored Request | |
157 | * sTW -> sIV Invalid, reincarnation in reverse direction | |
158 | * goes through sRQ | |
159 | * | |
160 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
161 | sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV, | |
162 | }, | |
163 | [DCCP_PKT_ACK] = { | |
164 | /* | |
165 | * sNO -> sIV No connection | |
166 | * sRQ -> sIV No connection | |
167 | * sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.) | |
168 | * sPO -> sPO Retransmitted Ack for Response, remain in PARTOPEN | |
169 | * sOP -> sOP Regular ACK, remain in OPEN | |
170 | * sCR -> sCR Ack in CLOSEREQ MAY be processed (8.3.) | |
171 | * sCG -> sCG Ack in CLOSING MAY be processed (8.3.) | |
172 | * sTW -> sIV | |
173 | * | |
174 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
175 | sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV | |
176 | }, | |
177 | [DCCP_PKT_DATA] = { | |
178 | /* | |
179 | * sNO -> sIV No connection | |
180 | * sRQ -> sIV No connection | |
181 | * sRS -> sIV No connection | |
182 | * sPO -> sIV MUST use DataAck in PARTOPEN state (8.1.5.) | |
183 | * sOP -> sOP Regular Data packet | |
184 | * sCR -> sCR Data in CLOSEREQ MAY be processed (8.3.) | |
185 | * sCG -> sCG Data in CLOSING MAY be processed (8.3.) | |
186 | * sTW -> sIV | |
187 | * | |
188 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
189 | sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV, | |
190 | }, | |
191 | [DCCP_PKT_DATAACK] = { | |
192 | /* | |
193 | * sNO -> sIV No connection | |
194 | * sRQ -> sIV No connection | |
195 | * sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.) | |
196 | * sPO -> sPO Remain in PARTOPEN state | |
197 | * sOP -> sOP Regular DataAck packet in OPEN state | |
198 | * sCR -> sCR DataAck in CLOSEREQ MAY be processed (8.3.) | |
199 | * sCG -> sCG DataAck in CLOSING MAY be processed (8.3.) | |
200 | * sTW -> sIV | |
201 | * | |
202 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
203 | sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV | |
204 | }, | |
205 | [DCCP_PKT_CLOSEREQ] = { | |
206 | /* | |
207 | * CLOSEREQ may only be sent by the server. | |
208 | * | |
209 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
210 | sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV | |
211 | }, | |
212 | [DCCP_PKT_CLOSE] = { | |
213 | /* | |
214 | * sNO -> sIV No connection | |
215 | * sRQ -> sIV No connection | |
216 | * sRS -> sIV No connection | |
217 | * sPO -> sCG Client-initiated close | |
218 | * sOP -> sCG Client-initiated close | |
219 | * sCR -> sCG Close in response to CloseReq (8.3.) | |
220 | * sCG -> sCG Retransmit | |
221 | * sTW -> sIV Late retransmit, already in TIME_WAIT | |
222 | * | |
223 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
224 | sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV | |
225 | }, | |
226 | [DCCP_PKT_RESET] = { | |
227 | /* | |
228 | * sNO -> sIV No connection | |
229 | * sRQ -> sTW Sync received or timeout, SHOULD send Reset (8.1.1.) | |
230 | * sRS -> sTW Response received without Request | |
231 | * sPO -> sTW Timeout, SHOULD send Reset (8.1.5.) | |
232 | * sOP -> sTW Connection reset | |
233 | * sCR -> sTW Connection reset | |
234 | * sCG -> sTW Connection reset | |
235 | * sTW -> sIG Ignore (don't refresh timer) | |
236 | * | |
237 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
238 | sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG | |
239 | }, | |
240 | [DCCP_PKT_SYNC] = { | |
241 | /* | |
242 | * We currently ignore Sync packets | |
243 | * | |
244 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
6613b617 | 245 | sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
2bc78049 PM |
246 | }, |
247 | [DCCP_PKT_SYNCACK] = { | |
248 | /* | |
249 | * We currently ignore SyncAck packets | |
250 | * | |
251 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
6613b617 | 252 | sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
2bc78049 PM |
253 | }, |
254 | }, | |
255 | [CT_DCCP_ROLE_SERVER] = { | |
256 | [DCCP_PKT_REQUEST] = { | |
257 | /* | |
258 | * sNO -> sIV Invalid | |
259 | * sRQ -> sIG Ignore, conntrack might be out of sync | |
260 | * sRS -> sIG Ignore, conntrack might be out of sync | |
261 | * sPO -> sIG Ignore, conntrack might be out of sync | |
262 | * sOP -> sIG Ignore, conntrack might be out of sync | |
263 | * sCR -> sIG Ignore, conntrack might be out of sync | |
264 | * sCG -> sIG Ignore, conntrack might be out of sync | |
265 | * sTW -> sRQ Reincarnation, must reverse roles | |
266 | * | |
267 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
268 | sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ | |
269 | }, | |
270 | [DCCP_PKT_RESPONSE] = { | |
271 | /* | |
272 | * sNO -> sIV Response without Request | |
273 | * sRQ -> sRS Response to clients Request | |
274 | * sRS -> sRS Retransmitted Response (8.1.3. SHOULD NOT) | |
275 | * sPO -> sIG Response to an ignored Request or late retransmit | |
276 | * sOP -> sIG Ignore, might be response to ignored Request | |
277 | * sCR -> sIG Ignore, might be response to ignored Request | |
278 | * sCG -> sIG Ignore, might be response to ignored Request | |
279 | * sTW -> sIV Invalid, Request from client in sTW moves to sRQ | |
280 | * | |
281 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
282 | sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV | |
283 | }, | |
284 | [DCCP_PKT_ACK] = { | |
285 | /* | |
286 | * sNO -> sIV No connection | |
287 | * sRQ -> sIV No connection | |
288 | * sRS -> sIV No connection | |
289 | * sPO -> sOP Enter OPEN state (8.1.5.) | |
290 | * sOP -> sOP Regular Ack in OPEN state | |
291 | * sCR -> sIV Waiting for Close from client | |
292 | * sCG -> sCG Ack in CLOSING MAY be processed (8.3.) | |
293 | * sTW -> sIV | |
294 | * | |
295 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
296 | sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV | |
297 | }, | |
298 | [DCCP_PKT_DATA] = { | |
299 | /* | |
300 | * sNO -> sIV No connection | |
301 | * sRQ -> sIV No connection | |
302 | * sRS -> sIV No connection | |
303 | * sPO -> sOP Enter OPEN state (8.1.5.) | |
304 | * sOP -> sOP Regular Data packet in OPEN state | |
305 | * sCR -> sIV Waiting for Close from client | |
306 | * sCG -> sCG Data in CLOSING MAY be processed (8.3.) | |
307 | * sTW -> sIV | |
308 | * | |
309 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
310 | sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV | |
311 | }, | |
312 | [DCCP_PKT_DATAACK] = { | |
313 | /* | |
314 | * sNO -> sIV No connection | |
315 | * sRQ -> sIV No connection | |
316 | * sRS -> sIV No connection | |
317 | * sPO -> sOP Enter OPEN state (8.1.5.) | |
318 | * sOP -> sOP Regular DataAck in OPEN state | |
319 | * sCR -> sIV Waiting for Close from client | |
320 | * sCG -> sCG Data in CLOSING MAY be processed (8.3.) | |
321 | * sTW -> sIV | |
322 | * | |
323 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
324 | sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV | |
325 | }, | |
326 | [DCCP_PKT_CLOSEREQ] = { | |
327 | /* | |
328 | * sNO -> sIV No connection | |
329 | * sRQ -> sIV No connection | |
330 | * sRS -> sIV No connection | |
331 | * sPO -> sOP -> sCR Move directly to CLOSEREQ (8.1.5.) | |
332 | * sOP -> sCR CloseReq in OPEN state | |
333 | * sCR -> sCR Retransmit | |
334 | * sCG -> sCR Simultaneous close, client sends another Close | |
335 | * sTW -> sIV Already closed | |
336 | * | |
337 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
338 | sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV | |
339 | }, | |
340 | [DCCP_PKT_CLOSE] = { | |
341 | /* | |
342 | * sNO -> sIV No connection | |
343 | * sRQ -> sIV No connection | |
344 | * sRS -> sIV No connection | |
345 | * sPO -> sOP -> sCG Move direcly to CLOSING | |
346 | * sOP -> sCG Move to CLOSING | |
347 | * sCR -> sIV Close after CloseReq is invalid | |
348 | * sCG -> sCG Retransmit | |
349 | * sTW -> sIV Already closed | |
350 | * | |
351 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
352 | sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV | |
353 | }, | |
354 | [DCCP_PKT_RESET] = { | |
355 | /* | |
356 | * sNO -> sIV No connection | |
357 | * sRQ -> sTW Reset in response to Request | |
358 | * sRS -> sTW Timeout, SHOULD send Reset (8.1.3.) | |
359 | * sPO -> sTW Timeout, SHOULD send Reset (8.1.3.) | |
360 | * sOP -> sTW | |
361 | * sCR -> sTW | |
362 | * sCG -> sTW | |
363 | * sTW -> sIG Ignore (don't refresh timer) | |
364 | * | |
365 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */ | |
366 | sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG | |
367 | }, | |
368 | [DCCP_PKT_SYNC] = { | |
369 | /* | |
370 | * We currently ignore Sync packets | |
371 | * | |
372 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
6613b617 | 373 | sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
2bc78049 PM |
374 | }, |
375 | [DCCP_PKT_SYNCACK] = { | |
376 | /* | |
377 | * We currently ignore SyncAck packets | |
378 | * | |
379 | * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ | |
6613b617 | 380 | sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, |
2bc78049 PM |
381 | }, |
382 | }, | |
383 | }; | |
384 | ||
9976fc6e FW |
385 | static noinline bool |
386 | dccp_new(struct nf_conn *ct, const struct sk_buff *skb, | |
62eec0d7 FW |
387 | const struct dccp_hdr *dh, |
388 | const struct nf_hook_state *hook_state) | |
2bc78049 | 389 | { |
c2a2c7e0 | 390 | struct net *net = nf_ct_net(ct); |
c51d3901 | 391 | struct nf_dccp_net *dn; |
2bc78049 PM |
392 | const char *msg; |
393 | u_int8_t state; | |
394 | ||
2bc78049 PM |
395 | state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE]; |
396 | switch (state) { | |
397 | default: | |
a95a7774 | 398 | dn = nf_dccp_pernet(net); |
1546000f | 399 | if (dn->dccp_loose == 0) { |
3d0b527b | 400 | msg = "not picking up existing connection "; |
2bc78049 PM |
401 | goto out_invalid; |
402 | } | |
c2168e6b | 403 | break; |
2bc78049 PM |
404 | case CT_DCCP_REQUEST: |
405 | break; | |
406 | case CT_DCCP_INVALID: | |
3d0b527b | 407 | msg = "invalid state transition "; |
2bc78049 PM |
408 | goto out_invalid; |
409 | } | |
410 | ||
411 | ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT; | |
412 | ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER; | |
413 | ct->proto.dccp.state = CT_DCCP_NONE; | |
e5fc9e7a CG |
414 | ct->proto.dccp.last_pkt = DCCP_PKT_REQUEST; |
415 | ct->proto.dccp.last_dir = IP_CT_DIR_ORIGINAL; | |
416 | ct->proto.dccp.handshake_seq = 0; | |
09f263cd | 417 | return true; |
2bc78049 PM |
418 | |
419 | out_invalid: | |
62eec0d7 | 420 | nf_ct_l4proto_log_invalid(skb, ct, hook_state, "%s", msg); |
09f263cd | 421 | return false; |
2bc78049 PM |
422 | } |
423 | ||
424 | static u64 dccp_ack_seq(const struct dccp_hdr *dh) | |
425 | { | |
426 | const struct dccp_hdr_ack_bits *dhack; | |
427 | ||
428 | dhack = (void *)dh + __dccp_basic_hdr_len(dh); | |
429 | return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + | |
430 | ntohl(dhack->dccph_ack_nr_low); | |
431 | } | |
432 | ||
0150ffba FW |
433 | static bool dccp_error(const struct dccp_hdr *dh, |
434 | struct sk_buff *skb, unsigned int dataoff, | |
435 | const struct nf_hook_state *state) | |
436 | { | |
ff0a3a7d FW |
437 | static const unsigned long require_seq48 = 1 << DCCP_PKT_REQUEST | |
438 | 1 << DCCP_PKT_RESPONSE | | |
439 | 1 << DCCP_PKT_CLOSEREQ | | |
440 | 1 << DCCP_PKT_CLOSE | | |
441 | 1 << DCCP_PKT_RESET | | |
442 | 1 << DCCP_PKT_SYNC | | |
443 | 1 << DCCP_PKT_SYNCACK; | |
0150ffba FW |
444 | unsigned int dccp_len = skb->len - dataoff; |
445 | unsigned int cscov; | |
446 | const char *msg; | |
ff0a3a7d FW |
447 | u8 type; |
448 | ||
449 | BUILD_BUG_ON(DCCP_PKT_INVALID >= BITS_PER_LONG); | |
0150ffba FW |
450 | |
451 | if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) || | |
452 | dh->dccph_doff * 4 > dccp_len) { | |
453 | msg = "nf_ct_dccp: truncated/malformed packet "; | |
454 | goto out_invalid; | |
455 | } | |
456 | ||
457 | cscov = dccp_len; | |
458 | if (dh->dccph_cscov) { | |
459 | cscov = (dh->dccph_cscov - 1) * 4; | |
460 | if (cscov > dccp_len) { | |
461 | msg = "nf_ct_dccp: bad checksum coverage "; | |
462 | goto out_invalid; | |
463 | } | |
464 | } | |
465 | ||
466 | if (state->hook == NF_INET_PRE_ROUTING && | |
467 | state->net->ct.sysctl_checksum && | |
468 | nf_checksum_partial(skb, state->hook, dataoff, cscov, | |
469 | IPPROTO_DCCP, state->pf)) { | |
470 | msg = "nf_ct_dccp: bad checksum "; | |
471 | goto out_invalid; | |
472 | } | |
473 | ||
ff0a3a7d FW |
474 | type = dh->dccph_type; |
475 | if (type >= DCCP_PKT_INVALID) { | |
0150ffba FW |
476 | msg = "nf_ct_dccp: reserved packet type "; |
477 | goto out_invalid; | |
478 | } | |
ff0a3a7d FW |
479 | |
480 | if (test_bit(type, &require_seq48) && !dh->dccph_x) { | |
481 | msg = "nf_ct_dccp: type lacks 48bit sequence numbers"; | |
482 | goto out_invalid; | |
483 | } | |
484 | ||
0150ffba FW |
485 | return false; |
486 | out_invalid: | |
62eec0d7 | 487 | nf_l4proto_log_invalid(skb, state, IPPROTO_DCCP, "%s", msg); |
0150ffba FW |
488 | return true; |
489 | } | |
490 | ||
ff0a3a7d FW |
491 | struct nf_conntrack_dccp_buf { |
492 | struct dccp_hdr dh; /* generic header part */ | |
493 | struct dccp_hdr_ext ext; /* optional depending dh->dccph_x */ | |
494 | union { /* depends on header type */ | |
495 | struct dccp_hdr_ack_bits ack; | |
496 | struct dccp_hdr_request req; | |
497 | struct dccp_hdr_response response; | |
498 | struct dccp_hdr_reset rst; | |
499 | } u; | |
500 | }; | |
501 | ||
502 | static struct dccp_hdr * | |
503 | dccp_header_pointer(const struct sk_buff *skb, int offset, const struct dccp_hdr *dh, | |
504 | struct nf_conntrack_dccp_buf *buf) | |
505 | { | |
506 | unsigned int hdrlen = __dccp_hdr_len(dh); | |
507 | ||
508 | if (hdrlen > sizeof(*buf)) | |
509 | return NULL; | |
510 | ||
511 | return skb_header_pointer(skb, offset, hdrlen, buf); | |
512 | } | |
513 | ||
a47c5404 FW |
514 | int nf_conntrack_dccp_packet(struct nf_conn *ct, struct sk_buff *skb, |
515 | unsigned int dataoff, | |
516 | enum ip_conntrack_info ctinfo, | |
517 | const struct nf_hook_state *state) | |
2bc78049 PM |
518 | { |
519 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
ff0a3a7d | 520 | struct nf_conntrack_dccp_buf _dh; |
2bc78049 PM |
521 | u_int8_t type, old_state, new_state; |
522 | enum ct_dccp_roles role; | |
c779e849 | 523 | unsigned int *timeouts; |
ff0a3a7d | 524 | struct dccp_hdr *dh; |
2bc78049 | 525 | |
ff0a3a7d | 526 | dh = skb_header_pointer(skb, dataoff, sizeof(*dh), &_dh.dh); |
9976fc6e | 527 | if (!dh) |
40616789 | 528 | return -NF_ACCEPT; |
9976fc6e | 529 | |
0150ffba FW |
530 | if (dccp_error(dh, skb, dataoff, state)) |
531 | return -NF_ACCEPT; | |
532 | ||
ff0a3a7d FW |
533 | /* pull again, including possible 48 bit sequences and subtype header */ |
534 | dh = dccp_header_pointer(skb, dataoff, dh, &_dh); | |
535 | if (!dh) | |
40616789 | 536 | return -NF_ACCEPT; |
ff0a3a7d | 537 | |
2bc78049 | 538 | type = dh->dccph_type; |
62eec0d7 | 539 | if (!nf_ct_is_confirmed(ct) && !dccp_new(ct, skb, dh, state)) |
9976fc6e | 540 | return -NF_ACCEPT; |
2bc78049 PM |
541 | |
542 | if (type == DCCP_PKT_RESET && | |
543 | !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { | |
544 | /* Tear down connection immediately if only reply is a RESET */ | |
718d4ad9 | 545 | nf_ct_kill_acct(ct, ctinfo, skb); |
2bc78049 PM |
546 | return NF_ACCEPT; |
547 | } | |
548 | ||
440f0d58 | 549 | spin_lock_bh(&ct->lock); |
2bc78049 PM |
550 | |
551 | role = ct->proto.dccp.role[dir]; | |
552 | old_state = ct->proto.dccp.state; | |
553 | new_state = dccp_state_table[role][type][old_state]; | |
554 | ||
555 | switch (new_state) { | |
556 | case CT_DCCP_REQUEST: | |
557 | if (old_state == CT_DCCP_TIMEWAIT && | |
558 | role == CT_DCCP_ROLE_SERVER) { | |
559 | /* Reincarnation in the reverse direction: reopen and | |
560 | * reverse client/server roles. */ | |
561 | ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT; | |
562 | ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER; | |
563 | } | |
564 | break; | |
565 | case CT_DCCP_RESPOND: | |
566 | if (old_state == CT_DCCP_REQUEST) | |
567 | ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh); | |
568 | break; | |
569 | case CT_DCCP_PARTOPEN: | |
570 | if (old_state == CT_DCCP_RESPOND && | |
571 | type == DCCP_PKT_ACK && | |
572 | dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq) | |
573 | set_bit(IPS_ASSURED_BIT, &ct->status); | |
574 | break; | |
575 | case CT_DCCP_IGNORE: | |
576 | /* | |
577 | * Connection tracking might be out of sync, so we ignore | |
578 | * packets that might establish a new connection and resync | |
579 | * if the server responds with a valid Response. | |
580 | */ | |
581 | if (ct->proto.dccp.last_dir == !dir && | |
582 | ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST && | |
583 | type == DCCP_PKT_RESPONSE) { | |
584 | ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT; | |
585 | ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER; | |
586 | ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh); | |
587 | new_state = CT_DCCP_RESPOND; | |
588 | break; | |
589 | } | |
590 | ct->proto.dccp.last_dir = dir; | |
591 | ct->proto.dccp.last_pkt = type; | |
592 | ||
440f0d58 | 593 | spin_unlock_bh(&ct->lock); |
62eec0d7 | 594 | nf_ct_l4proto_log_invalid(skb, ct, state, "%s", "invalid packet"); |
2bc78049 PM |
595 | return NF_ACCEPT; |
596 | case CT_DCCP_INVALID: | |
440f0d58 | 597 | spin_unlock_bh(&ct->lock); |
62eec0d7 | 598 | nf_ct_l4proto_log_invalid(skb, ct, state, "%s", "invalid state transition"); |
2bc78049 PM |
599 | return -NF_ACCEPT; |
600 | } | |
601 | ||
602 | ct->proto.dccp.last_dir = dir; | |
603 | ct->proto.dccp.last_pkt = type; | |
604 | ct->proto.dccp.state = new_state; | |
440f0d58 | 605 | spin_unlock_bh(&ct->lock); |
1546000f | 606 | |
b38b1f61 PNA |
607 | if (new_state != old_state) |
608 | nf_conntrack_event_cache(IPCT_PROTOINFO, ct); | |
609 | ||
c779e849 FW |
610 | timeouts = nf_ct_timeout_lookup(ct); |
611 | if (!timeouts) | |
a95a7774 | 612 | timeouts = nf_dccp_pernet(nf_ct_net(ct))->dccp_timeout; |
2c8503f5 | 613 | nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]); |
2bc78049 PM |
614 | |
615 | return NF_ACCEPT; | |
616 | } | |
617 | ||
c6dd940b FW |
618 | static bool dccp_can_early_drop(const struct nf_conn *ct) |
619 | { | |
620 | switch (ct->proto.dccp.state) { | |
621 | case CT_DCCP_CLOSEREQ: | |
622 | case CT_DCCP_CLOSING: | |
623 | case CT_DCCP_TIMEWAIT: | |
624 | return true; | |
625 | default: | |
626 | break; | |
627 | } | |
628 | ||
629 | return false; | |
630 | } | |
631 | ||
ea48cc83 | 632 | #ifdef CONFIG_NF_CONNTRACK_PROCFS |
37246a58 | 633 | static void dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct) |
2bc78049 | 634 | { |
37246a58 | 635 | seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]); |
2bc78049 | 636 | } |
ea48cc83 | 637 | #endif |
2bc78049 | 638 | |
c0cd1156 | 639 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
2bc78049 | 640 | static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla, |
86d21fc7 | 641 | struct nf_conn *ct, bool destroy) |
2bc78049 PM |
642 | { |
643 | struct nlattr *nest_parms; | |
644 | ||
440f0d58 | 645 | spin_lock_bh(&ct->lock); |
ae0be8de | 646 | nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP); |
2bc78049 PM |
647 | if (!nest_parms) |
648 | goto nla_put_failure; | |
86d21fc7 FW |
649 | if (nla_put_u8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state)) |
650 | goto nla_put_failure; | |
651 | ||
652 | if (destroy) | |
653 | goto skip_state; | |
654 | ||
655 | if (nla_put_u8(skb, CTA_PROTOINFO_DCCP_ROLE, | |
516ee48f DM |
656 | ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]) || |
657 | nla_put_be64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ, | |
b46f6ded ND |
658 | cpu_to_be64(ct->proto.dccp.handshake_seq), |
659 | CTA_PROTOINFO_DCCP_PAD)) | |
516ee48f | 660 | goto nla_put_failure; |
86d21fc7 | 661 | skip_state: |
2bc78049 | 662 | nla_nest_end(skb, nest_parms); |
440f0d58 | 663 | spin_unlock_bh(&ct->lock); |
86d21fc7 | 664 | |
2bc78049 PM |
665 | return 0; |
666 | ||
667 | nla_put_failure: | |
440f0d58 | 668 | spin_unlock_bh(&ct->lock); |
2bc78049 PM |
669 | return -1; |
670 | } | |
671 | ||
672 | static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = { | |
673 | [CTA_PROTOINFO_DCCP_STATE] = { .type = NLA_U8 }, | |
71951b64 | 674 | [CTA_PROTOINFO_DCCP_ROLE] = { .type = NLA_U8 }, |
a17c8598 | 675 | [CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 }, |
b46f6ded | 676 | [CTA_PROTOINFO_DCCP_PAD] = { .type = NLA_UNSPEC }, |
2bc78049 PM |
677 | }; |
678 | ||
39215846 FW |
679 | #define DCCP_NLATTR_SIZE ( \ |
680 | NLA_ALIGN(NLA_HDRLEN + 1) + \ | |
681 | NLA_ALIGN(NLA_HDRLEN + 1) + \ | |
682 | NLA_ALIGN(NLA_HDRLEN + sizeof(u64)) + \ | |
683 | NLA_ALIGN(NLA_HDRLEN + 0)) | |
684 | ||
2bc78049 PM |
685 | static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct) |
686 | { | |
687 | struct nlattr *attr = cda[CTA_PROTOINFO_DCCP]; | |
688 | struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1]; | |
689 | int err; | |
690 | ||
691 | if (!attr) | |
692 | return 0; | |
693 | ||
8cb08174 JB |
694 | err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_DCCP_MAX, attr, |
695 | dccp_nla_policy, NULL); | |
2bc78049 PM |
696 | if (err < 0) |
697 | return err; | |
698 | ||
699 | if (!tb[CTA_PROTOINFO_DCCP_STATE] || | |
71951b64 PNA |
700 | !tb[CTA_PROTOINFO_DCCP_ROLE] || |
701 | nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX || | |
702 | nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) { | |
2bc78049 | 703 | return -EINVAL; |
71951b64 | 704 | } |
2bc78049 | 705 | |
440f0d58 | 706 | spin_lock_bh(&ct->lock); |
2bc78049 | 707 | ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]); |
71951b64 PNA |
708 | if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) { |
709 | ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT; | |
710 | ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER; | |
711 | } else { | |
712 | ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER; | |
713 | ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT; | |
714 | } | |
a17c8598 PNA |
715 | if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) { |
716 | ct->proto.dccp.handshake_seq = | |
717 | be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ])); | |
718 | } | |
440f0d58 | 719 | spin_unlock_bh(&ct->lock); |
2bc78049 PM |
720 | return 0; |
721 | } | |
722 | #endif | |
723 | ||
a874752a | 724 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
50978462 PNA |
725 | |
726 | #include <linux/netfilter/nfnetlink.h> | |
727 | #include <linux/netfilter/nfnetlink_cttimeout.h> | |
728 | ||
8264deb8 G |
729 | static int dccp_timeout_nlattr_to_obj(struct nlattr *tb[], |
730 | struct net *net, void *data) | |
50978462 | 731 | { |
a95a7774 | 732 | struct nf_dccp_net *dn = nf_dccp_pernet(net); |
50978462 PNA |
733 | unsigned int *timeouts = data; |
734 | int i; | |
735 | ||
1d9a7acd FW |
736 | if (!timeouts) |
737 | timeouts = dn->dccp_timeout; | |
738 | ||
50978462 PNA |
739 | /* set default DCCP timeouts. */ |
740 | for (i=0; i<CT_DCCP_MAX; i++) | |
741 | timeouts[i] = dn->dccp_timeout[i]; | |
742 | ||
743 | /* there's a 1:1 mapping between attributes and protocol states. */ | |
744 | for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) { | |
745 | if (tb[i]) { | |
746 | timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ; | |
747 | } | |
748 | } | |
ef39078d FW |
749 | |
750 | timeouts[CTA_TIMEOUT_DCCP_UNSPEC] = timeouts[CTA_TIMEOUT_DCCP_REQUEST]; | |
50978462 PNA |
751 | return 0; |
752 | } | |
753 | ||
754 | static int | |
755 | dccp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) | |
756 | { | |
757 | const unsigned int *timeouts = data; | |
758 | int i; | |
759 | ||
516ee48f DM |
760 | for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) { |
761 | if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ))) | |
762 | goto nla_put_failure; | |
763 | } | |
50978462 PNA |
764 | return 0; |
765 | ||
766 | nla_put_failure: | |
767 | return -ENOSPC; | |
768 | } | |
769 | ||
770 | static const struct nla_policy | |
771 | dccp_timeout_nla_policy[CTA_TIMEOUT_DCCP_MAX+1] = { | |
772 | [CTA_TIMEOUT_DCCP_REQUEST] = { .type = NLA_U32 }, | |
773 | [CTA_TIMEOUT_DCCP_RESPOND] = { .type = NLA_U32 }, | |
774 | [CTA_TIMEOUT_DCCP_PARTOPEN] = { .type = NLA_U32 }, | |
775 | [CTA_TIMEOUT_DCCP_OPEN] = { .type = NLA_U32 }, | |
776 | [CTA_TIMEOUT_DCCP_CLOSEREQ] = { .type = NLA_U32 }, | |
777 | [CTA_TIMEOUT_DCCP_CLOSING] = { .type = NLA_U32 }, | |
778 | [CTA_TIMEOUT_DCCP_TIMEWAIT] = { .type = NLA_U32 }, | |
779 | }; | |
a874752a | 780 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
50978462 | 781 | |
2a389de8 | 782 | void nf_conntrack_dccp_init_net(struct net *net) |
84c39451 | 783 | { |
a95a7774 | 784 | struct nf_dccp_net *dn = nf_dccp_pernet(net); |
84c39451 | 785 | |
2a389de8 FW |
786 | /* default values */ |
787 | dn->dccp_loose = 1; | |
788 | dn->dccp_timeout[CT_DCCP_REQUEST] = 2 * DCCP_MSL; | |
789 | dn->dccp_timeout[CT_DCCP_RESPOND] = 4 * DCCP_MSL; | |
790 | dn->dccp_timeout[CT_DCCP_PARTOPEN] = 4 * DCCP_MSL; | |
791 | dn->dccp_timeout[CT_DCCP_OPEN] = 12 * 3600 * HZ; | |
792 | dn->dccp_timeout[CT_DCCP_CLOSEREQ] = 64 * HZ; | |
793 | dn->dccp_timeout[CT_DCCP_CLOSING] = 64 * HZ; | |
794 | dn->dccp_timeout[CT_DCCP_TIMEWAIT] = 2 * DCCP_MSL; | |
795 | ||
796 | /* timeouts[0] is unused, make it same as SYN_SENT so | |
797 | * ->timeouts[0] contains 'new' timeout, like udp or icmp. | |
798 | */ | |
799 | dn->dccp_timeout[CT_DCCP_NONE] = dn->dccp_timeout[CT_DCCP_REQUEST]; | |
deaa0a97 LZ |
800 | } |
801 | ||
dd2934a9 | 802 | const struct nf_conntrack_l4proto nf_conntrack_l4proto_dccp = { |
2bc78049 | 803 | .l4proto = IPPROTO_DCCP, |
c6dd940b | 804 | .can_early_drop = dccp_can_early_drop, |
ea48cc83 | 805 | #ifdef CONFIG_NF_CONNTRACK_PROCFS |
2bc78049 | 806 | .print_conntrack = dccp_print_conntrack, |
ea48cc83 | 807 | #endif |
c0cd1156 | 808 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
39215846 | 809 | .nlattr_size = DCCP_NLATTR_SIZE, |
2bc78049 PM |
810 | .to_nlattr = dccp_to_nlattr, |
811 | .from_nlattr = nlattr_to_dccp, | |
812 | .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, | |
a400c30e | 813 | .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, |
2bc78049 PM |
814 | .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, |
815 | .nla_policy = nf_ct_port_nla_policy, | |
816 | #endif | |
a874752a | 817 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
50978462 PNA |
818 | .ctnl_timeout = { |
819 | .nlattr_to_obj = dccp_timeout_nlattr_to_obj, | |
820 | .obj_to_nlattr = dccp_timeout_obj_to_nlattr, | |
821 | .nlattr_max = CTA_TIMEOUT_DCCP_MAX, | |
822 | .obj_size = sizeof(unsigned int) * CT_DCCP_MAX, | |
823 | .nla_policy = dccp_timeout_nla_policy, | |
824 | }, | |
a874752a | 825 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
2bc78049 | 826 | }; |