netfilter: nf_conntrack: pass template to l4proto ->error() handler
[linux-2.6.git] / net / netfilter / nf_conntrack_proto_dccp.c
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
19 #include <net/net_namespace.h>
20 #include <net/netns/generic.h>
21
22 #include <linux/netfilter/nfnetlink_conntrack.h>
23 #include <net/netfilter/nf_conntrack.h>
24 #include <net/netfilter/nf_conntrack_l4proto.h>
25 #include <net/netfilter/nf_conntrack_ecache.h>
26 #include <net/netfilter/nf_log.h>
27
28 /* Timeouts are based on values from RFC4340:
29  *
30  * - REQUEST:
31  *
32  *   8.1.2. Client Request
33  *
34  *   A client MAY give up on its DCCP-Requests after some time
35  *   (3 minutes, for example).
36  *
37  * - RESPOND:
38  *
39  *   8.1.3. Server Response
40  *
41  *   It MAY also leave the RESPOND state for CLOSED after a timeout of
42  *   not less than 4MSL (8 minutes);
43  *
44  * - PARTOPEN:
45  *
46  *   8.1.5. Handshake Completion
47  *
48  *   If the client remains in PARTOPEN for more than 4MSL (8 minutes),
49  *   it SHOULD reset the connection with Reset Code 2, "Aborted".
50  *
51  * - OPEN:
52  *
53  *   The DCCP timestamp overflows after 11.9 hours. If the connection
54  *   stays idle this long the sequence number won't be recognized
55  *   as valid anymore.
56  *
57  * - CLOSEREQ/CLOSING:
58  *
59  *   8.3. Termination
60  *
61  *   The retransmission timer should initially be set to go off in two
62  *   round-trip times and should back off to not less than once every
63  *   64 seconds ...
64  *
65  * - TIMEWAIT:
66  *
67  *   4.3. States
68  *
69  *   A server or client socket remains in this state for 2MSL (4 minutes)
70  *   after the connection has been town down, ...
71  */
72
73 #define DCCP_MSL (2 * 60 * HZ)
74
75 static const char * const dccp_state_names[] = {
76         [CT_DCCP_NONE]          = "NONE",
77         [CT_DCCP_REQUEST]       = "REQUEST",
78         [CT_DCCP_RESPOND]       = "RESPOND",
79         [CT_DCCP_PARTOPEN]      = "PARTOPEN",
80         [CT_DCCP_OPEN]          = "OPEN",
81         [CT_DCCP_CLOSEREQ]      = "CLOSEREQ",
82         [CT_DCCP_CLOSING]       = "CLOSING",
83         [CT_DCCP_TIMEWAIT]      = "TIMEWAIT",
84         [CT_DCCP_IGNORE]        = "IGNORE",
85         [CT_DCCP_INVALID]       = "INVALID",
86 };
87
88 #define sNO     CT_DCCP_NONE
89 #define sRQ     CT_DCCP_REQUEST
90 #define sRS     CT_DCCP_RESPOND
91 #define sPO     CT_DCCP_PARTOPEN
92 #define sOP     CT_DCCP_OPEN
93 #define sCR     CT_DCCP_CLOSEREQ
94 #define sCG     CT_DCCP_CLOSING
95 #define sTW     CT_DCCP_TIMEWAIT
96 #define sIG     CT_DCCP_IGNORE
97 #define sIV     CT_DCCP_INVALID
98
99 /*
100  * DCCP state transistion table
101  *
102  * The assumption is the same as for TCP tracking:
103  *
104  * We are the man in the middle. All the packets go through us but might
105  * get lost in transit to the destination. It is assumed that the destination
106  * can't receive segments we haven't seen.
107  *
108  * The following states exist:
109  *
110  * NONE:        Initial state, expecting Request
111  * REQUEST:     Request seen, waiting for Response from server
112  * RESPOND:     Response from server seen, waiting for Ack from client
113  * PARTOPEN:    Ack after Response seen, waiting for packet other than Response,
114  *              Reset or Sync from server
115  * OPEN:        Packet other than Response, Reset or Sync seen
116  * CLOSEREQ:    CloseReq from server seen, expecting Close from client
117  * CLOSING:     Close seen, expecting Reset
118  * TIMEWAIT:    Reset seen
119  * IGNORE:      Not determinable whether packet is valid
120  *
121  * Some states exist only on one side of the connection: REQUEST, RESPOND,
122  * PARTOPEN, CLOSEREQ. For the other side these states are equivalent to
123  * the one it was in before.
124  *
125  * Packets are marked as ignored (sIG) if we don't know if they're valid
126  * (for example a reincarnation of a connection we didn't notice is dead
127  * already) and the server may send back a connection closing Reset or a
128  * Response. They're also used for Sync/SyncAck packets, which we don't
129  * care about.
130  */
131 static const u_int8_t
132 dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = {
133         [CT_DCCP_ROLE_CLIENT] = {
134                 [DCCP_PKT_REQUEST] = {
135                 /*
136                  * sNO -> sRQ           Regular Request
137                  * sRQ -> sRQ           Retransmitted Request or reincarnation
138                  * sRS -> sRS           Retransmitted Request (apparently Response
139                  *                      got lost after we saw it) or reincarnation
140                  * sPO -> sIG           Ignore, conntrack might be out of sync
141                  * sOP -> sIG           Ignore, conntrack might be out of sync
142                  * sCR -> sIG           Ignore, conntrack might be out of sync
143                  * sCG -> sIG           Ignore, conntrack might be out of sync
144                  * sTW -> sRQ           Reincarnation
145                  *
146                  *      sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */
147                         sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ,
148                 },
149                 [DCCP_PKT_RESPONSE] = {
150                 /*
151                  * sNO -> sIV           Invalid
152                  * sRQ -> sIG           Ignore, might be response to ignored Request
153                  * sRS -> sIG           Ignore, might be response to ignored Request
154                  * sPO -> sIG           Ignore, might be response to ignored Request
155                  * sOP -> sIG           Ignore, might be response to ignored Request
156                  * sCR -> sIG           Ignore, might be response to ignored Request
157                  * sCG -> sIG           Ignore, might be response to ignored Request
158                  * sTW -> sIV           Invalid, reincarnation in reverse direction
159                  *                      goes through sRQ
160                  *
161                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
162                         sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV,
163                 },
164                 [DCCP_PKT_ACK] = {
165                 /*
166                  * sNO -> sIV           No connection
167                  * sRQ -> sIV           No connection
168                  * sRS -> sPO           Ack for Response, move to PARTOPEN (8.1.5.)
169                  * sPO -> sPO           Retransmitted Ack for Response, remain in PARTOPEN
170                  * sOP -> sOP           Regular ACK, remain in OPEN
171                  * sCR -> sCR           Ack in CLOSEREQ MAY be processed (8.3.)
172                  * sCG -> sCG           Ack in CLOSING MAY be processed (8.3.)
173                  * sTW -> sIV
174                  *
175                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
176                         sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
177                 },
178                 [DCCP_PKT_DATA] = {
179                 /*
180                  * sNO -> sIV           No connection
181                  * sRQ -> sIV           No connection
182                  * sRS -> sIV           No connection
183                  * sPO -> sIV           MUST use DataAck in PARTOPEN state (8.1.5.)
184                  * sOP -> sOP           Regular Data packet
185                  * sCR -> sCR           Data in CLOSEREQ MAY be processed (8.3.)
186                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
187                  * sTW -> sIV
188                  *
189                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
190                         sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV,
191                 },
192                 [DCCP_PKT_DATAACK] = {
193                 /*
194                  * sNO -> sIV           No connection
195                  * sRQ -> sIV           No connection
196                  * sRS -> sPO           Ack for Response, move to PARTOPEN (8.1.5.)
197                  * sPO -> sPO           Remain in PARTOPEN state
198                  * sOP -> sOP           Regular DataAck packet in OPEN state
199                  * sCR -> sCR           DataAck in CLOSEREQ MAY be processed (8.3.)
200                  * sCG -> sCG           DataAck in CLOSING MAY be processed (8.3.)
201                  * sTW -> sIV
202                  *
203                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
204                         sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
205                 },
206                 [DCCP_PKT_CLOSEREQ] = {
207                 /*
208                  * CLOSEREQ may only be sent by the server.
209                  *
210                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
211                         sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV
212                 },
213                 [DCCP_PKT_CLOSE] = {
214                 /*
215                  * sNO -> sIV           No connection
216                  * sRQ -> sIV           No connection
217                  * sRS -> sIV           No connection
218                  * sPO -> sCG           Client-initiated close
219                  * sOP -> sCG           Client-initiated close
220                  * sCR -> sCG           Close in response to CloseReq (8.3.)
221                  * sCG -> sCG           Retransmit
222                  * sTW -> sIV           Late retransmit, already in TIME_WAIT
223                  *
224                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
225                         sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV
226                 },
227                 [DCCP_PKT_RESET] = {
228                 /*
229                  * sNO -> sIV           No connection
230                  * sRQ -> sTW           Sync received or timeout, SHOULD send Reset (8.1.1.)
231                  * sRS -> sTW           Response received without Request
232                  * sPO -> sTW           Timeout, SHOULD send Reset (8.1.5.)
233                  * sOP -> sTW           Connection reset
234                  * sCR -> sTW           Connection reset
235                  * sCG -> sTW           Connection reset
236                  * sTW -> sIG           Ignore (don't refresh timer)
237                  *
238                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
239                         sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG
240                 },
241                 [DCCP_PKT_SYNC] = {
242                 /*
243                  * We currently ignore Sync packets
244                  *
245                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
246                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
247                 },
248                 [DCCP_PKT_SYNCACK] = {
249                 /*
250                  * We currently ignore SyncAck packets
251                  *
252                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
253                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
254                 },
255         },
256         [CT_DCCP_ROLE_SERVER] = {
257                 [DCCP_PKT_REQUEST] = {
258                 /*
259                  * sNO -> sIV           Invalid
260                  * sRQ -> sIG           Ignore, conntrack might be out of sync
261                  * sRS -> sIG           Ignore, conntrack might be out of sync
262                  * sPO -> sIG           Ignore, conntrack might be out of sync
263                  * sOP -> sIG           Ignore, conntrack might be out of sync
264                  * sCR -> sIG           Ignore, conntrack might be out of sync
265                  * sCG -> sIG           Ignore, conntrack might be out of sync
266                  * sTW -> sRQ           Reincarnation, must reverse roles
267                  *
268                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
269                         sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ
270                 },
271                 [DCCP_PKT_RESPONSE] = {
272                 /*
273                  * sNO -> sIV           Response without Request
274                  * sRQ -> sRS           Response to clients Request
275                  * sRS -> sRS           Retransmitted Response (8.1.3. SHOULD NOT)
276                  * sPO -> sIG           Response to an ignored Request or late retransmit
277                  * sOP -> sIG           Ignore, might be response to ignored Request
278                  * sCR -> sIG           Ignore, might be response to ignored Request
279                  * sCG -> sIG           Ignore, might be response to ignored Request
280                  * sTW -> sIV           Invalid, Request from client in sTW moves to sRQ
281                  *
282                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
283                         sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV
284                 },
285                 [DCCP_PKT_ACK] = {
286                 /*
287                  * sNO -> sIV           No connection
288                  * sRQ -> sIV           No connection
289                  * sRS -> sIV           No connection
290                  * sPO -> sOP           Enter OPEN state (8.1.5.)
291                  * sOP -> sOP           Regular Ack in OPEN state
292                  * sCR -> sIV           Waiting for Close from client
293                  * sCG -> sCG           Ack in CLOSING MAY be processed (8.3.)
294                  * sTW -> sIV
295                  *
296                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
297                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
298                 },
299                 [DCCP_PKT_DATA] = {
300                 /*
301                  * sNO -> sIV           No connection
302                  * sRQ -> sIV           No connection
303                  * sRS -> sIV           No connection
304                  * sPO -> sOP           Enter OPEN state (8.1.5.)
305                  * sOP -> sOP           Regular Data packet in OPEN state
306                  * sCR -> sIV           Waiting for Close from client
307                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
308                  * sTW -> sIV
309                  *
310                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
311                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
312                 },
313                 [DCCP_PKT_DATAACK] = {
314                 /*
315                  * sNO -> sIV           No connection
316                  * sRQ -> sIV           No connection
317                  * sRS -> sIV           No connection
318                  * sPO -> sOP           Enter OPEN state (8.1.5.)
319                  * sOP -> sOP           Regular DataAck in OPEN state
320                  * sCR -> sIV           Waiting for Close from client
321                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
322                  * sTW -> sIV
323                  *
324                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
325                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
326                 },
327                 [DCCP_PKT_CLOSEREQ] = {
328                 /*
329                  * sNO -> sIV           No connection
330                  * sRQ -> sIV           No connection
331                  * sRS -> sIV           No connection
332                  * sPO -> sOP -> sCR    Move directly to CLOSEREQ (8.1.5.)
333                  * sOP -> sCR           CloseReq in OPEN state
334                  * sCR -> sCR           Retransmit
335                  * sCG -> sCR           Simultaneous close, client sends another Close
336                  * sTW -> sIV           Already closed
337                  *
338                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
339                         sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV
340                 },
341                 [DCCP_PKT_CLOSE] = {
342                 /*
343                  * sNO -> sIV           No connection
344                  * sRQ -> sIV           No connection
345                  * sRS -> sIV           No connection
346                  * sPO -> sOP -> sCG    Move direcly to CLOSING
347                  * sOP -> sCG           Move to CLOSING
348                  * sCR -> sIV           Close after CloseReq is invalid
349                  * sCG -> sCG           Retransmit
350                  * sTW -> sIV           Already closed
351                  *
352                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
353                         sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV
354                 },
355                 [DCCP_PKT_RESET] = {
356                 /*
357                  * sNO -> sIV           No connection
358                  * sRQ -> sTW           Reset in response to Request
359                  * sRS -> sTW           Timeout, SHOULD send Reset (8.1.3.)
360                  * sPO -> sTW           Timeout, SHOULD send Reset (8.1.3.)
361                  * sOP -> sTW
362                  * sCR -> sTW
363                  * sCG -> sTW
364                  * sTW -> sIG           Ignore (don't refresh timer)
365                  *
366                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */
367                         sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG
368                 },
369                 [DCCP_PKT_SYNC] = {
370                 /*
371                  * We currently ignore Sync packets
372                  *
373                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
374                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
375                 },
376                 [DCCP_PKT_SYNCACK] = {
377                 /*
378                  * We currently ignore SyncAck packets
379                  *
380                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
381                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
382                 },
383         },
384 };
385
386 /* this module per-net specifics */
387 static int dccp_net_id __read_mostly;
388 struct dccp_net {
389         int dccp_loose;
390         unsigned int dccp_timeout[CT_DCCP_MAX + 1];
391 #ifdef CONFIG_SYSCTL
392         struct ctl_table_header *sysctl_header;
393         struct ctl_table *sysctl_table;
394 #endif
395 };
396
397 static inline struct dccp_net *dccp_pernet(struct net *net)
398 {
399         return net_generic(net, dccp_net_id);
400 }
401
402 static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
403                               struct nf_conntrack_tuple *tuple)
404 {
405         struct dccp_hdr _hdr, *dh;
406
407         dh = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
408         if (dh == NULL)
409                 return false;
410
411         tuple->src.u.dccp.port = dh->dccph_sport;
412         tuple->dst.u.dccp.port = dh->dccph_dport;
413         return true;
414 }
415
416 static bool dccp_invert_tuple(struct nf_conntrack_tuple *inv,
417                               const struct nf_conntrack_tuple *tuple)
418 {
419         inv->src.u.dccp.port = tuple->dst.u.dccp.port;
420         inv->dst.u.dccp.port = tuple->src.u.dccp.port;
421         return true;
422 }
423
424 static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb,
425                      unsigned int dataoff)
426 {
427         struct net *net = nf_ct_net(ct);
428         struct dccp_net *dn;
429         struct dccp_hdr _dh, *dh;
430         const char *msg;
431         u_int8_t state;
432
433         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
434         BUG_ON(dh == NULL);
435
436         state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE];
437         switch (state) {
438         default:
439                 dn = dccp_pernet(net);
440                 if (dn->dccp_loose == 0) {
441                         msg = "nf_ct_dccp: not picking up existing connection ";
442                         goto out_invalid;
443                 }
444         case CT_DCCP_REQUEST:
445                 break;
446         case CT_DCCP_INVALID:
447                 msg = "nf_ct_dccp: invalid state transition ";
448                 goto out_invalid;
449         }
450
451         ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
452         ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
453         ct->proto.dccp.state = CT_DCCP_NONE;
454         return true;
455
456 out_invalid:
457         if (LOG_INVALID(net, IPPROTO_DCCP))
458                 nf_log_packet(nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL, msg);
459         return false;
460 }
461
462 static u64 dccp_ack_seq(const struct dccp_hdr *dh)
463 {
464         const struct dccp_hdr_ack_bits *dhack;
465
466         dhack = (void *)dh + __dccp_basic_hdr_len(dh);
467         return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
468                      ntohl(dhack->dccph_ack_nr_low);
469 }
470
471 static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
472                        unsigned int dataoff, enum ip_conntrack_info ctinfo,
473                        u_int8_t pf, unsigned int hooknum)
474 {
475         struct net *net = nf_ct_net(ct);
476         struct dccp_net *dn;
477         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
478         struct dccp_hdr _dh, *dh;
479         u_int8_t type, old_state, new_state;
480         enum ct_dccp_roles role;
481
482         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
483         BUG_ON(dh == NULL);
484         type = dh->dccph_type;
485
486         if (type == DCCP_PKT_RESET &&
487             !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
488                 /* Tear down connection immediately if only reply is a RESET */
489                 nf_ct_kill_acct(ct, ctinfo, skb);
490                 return NF_ACCEPT;
491         }
492
493         spin_lock_bh(&ct->lock);
494
495         role = ct->proto.dccp.role[dir];
496         old_state = ct->proto.dccp.state;
497         new_state = dccp_state_table[role][type][old_state];
498
499         switch (new_state) {
500         case CT_DCCP_REQUEST:
501                 if (old_state == CT_DCCP_TIMEWAIT &&
502                     role == CT_DCCP_ROLE_SERVER) {
503                         /* Reincarnation in the reverse direction: reopen and
504                          * reverse client/server roles. */
505                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT;
506                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER;
507                 }
508                 break;
509         case CT_DCCP_RESPOND:
510                 if (old_state == CT_DCCP_REQUEST)
511                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
512                 break;
513         case CT_DCCP_PARTOPEN:
514                 if (old_state == CT_DCCP_RESPOND &&
515                     type == DCCP_PKT_ACK &&
516                     dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq)
517                         set_bit(IPS_ASSURED_BIT, &ct->status);
518                 break;
519         case CT_DCCP_IGNORE:
520                 /*
521                  * Connection tracking might be out of sync, so we ignore
522                  * packets that might establish a new connection and resync
523                  * if the server responds with a valid Response.
524                  */
525                 if (ct->proto.dccp.last_dir == !dir &&
526                     ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST &&
527                     type == DCCP_PKT_RESPONSE) {
528                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT;
529                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER;
530                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
531                         new_state = CT_DCCP_RESPOND;
532                         break;
533                 }
534                 ct->proto.dccp.last_dir = dir;
535                 ct->proto.dccp.last_pkt = type;
536
537                 spin_unlock_bh(&ct->lock);
538                 if (LOG_INVALID(net, IPPROTO_DCCP))
539                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
540                                       "nf_ct_dccp: invalid packet ignored ");
541                 return NF_ACCEPT;
542         case CT_DCCP_INVALID:
543                 spin_unlock_bh(&ct->lock);
544                 if (LOG_INVALID(net, IPPROTO_DCCP))
545                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
546                                       "nf_ct_dccp: invalid state transition ");
547                 return -NF_ACCEPT;
548         }
549
550         ct->proto.dccp.last_dir = dir;
551         ct->proto.dccp.last_pkt = type;
552         ct->proto.dccp.state = new_state;
553         spin_unlock_bh(&ct->lock);
554
555         if (new_state != old_state)
556                 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
557
558         dn = dccp_pernet(net);
559         nf_ct_refresh_acct(ct, ctinfo, skb, dn->dccp_timeout[new_state]);
560
561         return NF_ACCEPT;
562 }
563
564 static int dccp_error(struct net *net, struct nf_conn *tmpl,
565                       struct sk_buff *skb, unsigned int dataoff,
566                       enum ip_conntrack_info *ctinfo,
567                       u_int8_t pf, unsigned int hooknum)
568 {
569         struct dccp_hdr _dh, *dh;
570         unsigned int dccp_len = skb->len - dataoff;
571         unsigned int cscov;
572         const char *msg;
573
574         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
575         if (dh == NULL) {
576                 msg = "nf_ct_dccp: short packet ";
577                 goto out_invalid;
578         }
579
580         if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) ||
581             dh->dccph_doff * 4 > dccp_len) {
582                 msg = "nf_ct_dccp: truncated/malformed packet ";
583                 goto out_invalid;
584         }
585
586         cscov = dccp_len;
587         if (dh->dccph_cscov) {
588                 cscov = (dh->dccph_cscov - 1) * 4;
589                 if (cscov > dccp_len) {
590                         msg = "nf_ct_dccp: bad checksum coverage ";
591                         goto out_invalid;
592                 }
593         }
594
595         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
596             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP,
597                                 pf)) {
598                 msg = "nf_ct_dccp: bad checksum ";
599                 goto out_invalid;
600         }
601
602         if (dh->dccph_type >= DCCP_PKT_INVALID) {
603                 msg = "nf_ct_dccp: reserved packet type ";
604                 goto out_invalid;
605         }
606
607         return NF_ACCEPT;
608
609 out_invalid:
610         if (LOG_INVALID(net, IPPROTO_DCCP))
611                 nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg);
612         return -NF_ACCEPT;
613 }
614
615 static int dccp_print_tuple(struct seq_file *s,
616                             const struct nf_conntrack_tuple *tuple)
617 {
618         return seq_printf(s, "sport=%hu dport=%hu ",
619                           ntohs(tuple->src.u.dccp.port),
620                           ntohs(tuple->dst.u.dccp.port));
621 }
622
623 static int dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
624 {
625         return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
626 }
627
628 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
629 static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
630                           struct nf_conn *ct)
631 {
632         struct nlattr *nest_parms;
633
634         spin_lock_bh(&ct->lock);
635         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
636         if (!nest_parms)
637                 goto nla_put_failure;
638         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state);
639         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_ROLE,
640                    ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]);
641         NLA_PUT_BE64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ,
642                      cpu_to_be64(ct->proto.dccp.handshake_seq));
643         nla_nest_end(skb, nest_parms);
644         spin_unlock_bh(&ct->lock);
645         return 0;
646
647 nla_put_failure:
648         spin_unlock_bh(&ct->lock);
649         return -1;
650 }
651
652 static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
653         [CTA_PROTOINFO_DCCP_STATE]      = { .type = NLA_U8 },
654         [CTA_PROTOINFO_DCCP_ROLE]       = { .type = NLA_U8 },
655         [CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 },
656 };
657
658 static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
659 {
660         struct nlattr *attr = cda[CTA_PROTOINFO_DCCP];
661         struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1];
662         int err;
663
664         if (!attr)
665                 return 0;
666
667         err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr,
668                                dccp_nla_policy);
669         if (err < 0)
670                 return err;
671
672         if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
673             !tb[CTA_PROTOINFO_DCCP_ROLE] ||
674             nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX ||
675             nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) {
676                 return -EINVAL;
677         }
678
679         spin_lock_bh(&ct->lock);
680         ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
681         if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) {
682                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
683                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
684         } else {
685                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
686                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
687         }
688         if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) {
689                 ct->proto.dccp.handshake_seq =
690                 be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]));
691         }
692         spin_unlock_bh(&ct->lock);
693         return 0;
694 }
695
696 static int dccp_nlattr_size(void)
697 {
698         return nla_total_size(0)        /* CTA_PROTOINFO_DCCP */
699                 + nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
700 }
701 #endif
702
703 #ifdef CONFIG_SYSCTL
704 /* template, data assigned later */
705 static struct ctl_table dccp_sysctl_table[] = {
706         {
707                 .procname       = "nf_conntrack_dccp_timeout_request",
708                 .maxlen         = sizeof(unsigned int),
709                 .mode           = 0644,
710                 .proc_handler   = proc_dointvec_jiffies,
711         },
712         {
713                 .procname       = "nf_conntrack_dccp_timeout_respond",
714                 .maxlen         = sizeof(unsigned int),
715                 .mode           = 0644,
716                 .proc_handler   = proc_dointvec_jiffies,
717         },
718         {
719                 .procname       = "nf_conntrack_dccp_timeout_partopen",
720                 .maxlen         = sizeof(unsigned int),
721                 .mode           = 0644,
722                 .proc_handler   = proc_dointvec_jiffies,
723         },
724         {
725                 .procname       = "nf_conntrack_dccp_timeout_open",
726                 .maxlen         = sizeof(unsigned int),
727                 .mode           = 0644,
728                 .proc_handler   = proc_dointvec_jiffies,
729         },
730         {
731                 .procname       = "nf_conntrack_dccp_timeout_closereq",
732                 .maxlen         = sizeof(unsigned int),
733                 .mode           = 0644,
734                 .proc_handler   = proc_dointvec_jiffies,
735         },
736         {
737                 .procname       = "nf_conntrack_dccp_timeout_closing",
738                 .maxlen         = sizeof(unsigned int),
739                 .mode           = 0644,
740                 .proc_handler   = proc_dointvec_jiffies,
741         },
742         {
743                 .procname       = "nf_conntrack_dccp_timeout_timewait",
744                 .maxlen         = sizeof(unsigned int),
745                 .mode           = 0644,
746                 .proc_handler   = proc_dointvec_jiffies,
747         },
748         {
749                 .procname       = "nf_conntrack_dccp_loose",
750                 .maxlen         = sizeof(int),
751                 .mode           = 0644,
752                 .proc_handler   = proc_dointvec,
753         },
754         { }
755 };
756 #endif /* CONFIG_SYSCTL */
757
758 static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = {
759         .l3proto                = AF_INET,
760         .l4proto                = IPPROTO_DCCP,
761         .name                   = "dccp",
762         .pkt_to_tuple           = dccp_pkt_to_tuple,
763         .invert_tuple           = dccp_invert_tuple,
764         .new                    = dccp_new,
765         .packet                 = dccp_packet,
766         .error                  = dccp_error,
767         .print_tuple            = dccp_print_tuple,
768         .print_conntrack        = dccp_print_conntrack,
769 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
770         .to_nlattr              = dccp_to_nlattr,
771         .nlattr_size            = dccp_nlattr_size,
772         .from_nlattr            = nlattr_to_dccp,
773         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
774         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
775         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
776         .nla_policy             = nf_ct_port_nla_policy,
777 #endif
778 };
779
780 static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = {
781         .l3proto                = AF_INET6,
782         .l4proto                = IPPROTO_DCCP,
783         .name                   = "dccp",
784         .pkt_to_tuple           = dccp_pkt_to_tuple,
785         .invert_tuple           = dccp_invert_tuple,
786         .new                    = dccp_new,
787         .packet                 = dccp_packet,
788         .error                  = dccp_error,
789         .print_tuple            = dccp_print_tuple,
790         .print_conntrack        = dccp_print_conntrack,
791 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
792         .to_nlattr              = dccp_to_nlattr,
793         .nlattr_size            = dccp_nlattr_size,
794         .from_nlattr            = nlattr_to_dccp,
795         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
796         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
797         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
798         .nla_policy             = nf_ct_port_nla_policy,
799 #endif
800 };
801
802 static __net_init int dccp_net_init(struct net *net)
803 {
804         struct dccp_net *dn = dccp_pernet(net);
805
806         /* default values */
807         dn->dccp_loose = 1;
808         dn->dccp_timeout[CT_DCCP_REQUEST]       = 2 * DCCP_MSL;
809         dn->dccp_timeout[CT_DCCP_RESPOND]       = 4 * DCCP_MSL;
810         dn->dccp_timeout[CT_DCCP_PARTOPEN]      = 4 * DCCP_MSL;
811         dn->dccp_timeout[CT_DCCP_OPEN]          = 12 * 3600 * HZ;
812         dn->dccp_timeout[CT_DCCP_CLOSEREQ]      = 64 * HZ;
813         dn->dccp_timeout[CT_DCCP_CLOSING]       = 64 * HZ;
814         dn->dccp_timeout[CT_DCCP_TIMEWAIT]      = 2 * DCCP_MSL;
815
816 #ifdef CONFIG_SYSCTL
817         dn->sysctl_table = kmemdup(dccp_sysctl_table,
818                         sizeof(dccp_sysctl_table), GFP_KERNEL);
819         if (!dn->sysctl_table)
820                 return -ENOMEM;
821
822         dn->sysctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST];
823         dn->sysctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND];
824         dn->sysctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN];
825         dn->sysctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN];
826         dn->sysctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ];
827         dn->sysctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
828         dn->sysctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
829         dn->sysctl_table[7].data = &dn->dccp_loose;
830
831         dn->sysctl_header = register_net_sysctl_table(net,
832                         nf_net_netfilter_sysctl_path, dn->sysctl_table);
833         if (!dn->sysctl_header) {
834                 kfree(dn->sysctl_table);
835                 return -ENOMEM;
836         }
837 #endif
838
839         return 0;
840 }
841
842 static __net_exit void dccp_net_exit(struct net *net)
843 {
844         struct dccp_net *dn = dccp_pernet(net);
845 #ifdef CONFIG_SYSCTL
846         unregister_net_sysctl_table(dn->sysctl_header);
847         kfree(dn->sysctl_table);
848 #endif
849 }
850
851 static struct pernet_operations dccp_net_ops = {
852         .init = dccp_net_init,
853         .exit = dccp_net_exit,
854         .id   = &dccp_net_id,
855         .size = sizeof(struct dccp_net),
856 };
857
858 static int __init nf_conntrack_proto_dccp_init(void)
859 {
860         int err;
861
862         err = register_pernet_subsys(&dccp_net_ops);
863         if (err < 0)
864                 goto err1;
865
866         err = nf_conntrack_l4proto_register(&dccp_proto4);
867         if (err < 0)
868                 goto err2;
869
870         err = nf_conntrack_l4proto_register(&dccp_proto6);
871         if (err < 0)
872                 goto err3;
873         return 0;
874
875 err3:
876         nf_conntrack_l4proto_unregister(&dccp_proto4);
877 err2:
878         unregister_pernet_subsys(&dccp_net_ops);
879 err1:
880         return err;
881 }
882
883 static void __exit nf_conntrack_proto_dccp_fini(void)
884 {
885         unregister_pernet_subsys(&dccp_net_ops);
886         nf_conntrack_l4proto_unregister(&dccp_proto6);
887         nf_conntrack_l4proto_unregister(&dccp_proto4);
888 }
889
890 module_init(nf_conntrack_proto_dccp_init);
891 module_exit(nf_conntrack_proto_dccp_fini);
892
893 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
894 MODULE_DESCRIPTION("DCCP connection tracking protocol helper");
895 MODULE_LICENSE("GPL");