SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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_log.h>
  26
  27 /* Timeouts are based on values from RFC4340:
  28  *
  29  * - REQUEST:
  30  *
  31  *   8.1.2. Client Request
  32  *
  33  *   A client MAY give up on its DCCP-Requests after some time
  34  *   (3 minutes, for example).
  35  *
  36  * - RESPOND:
  37  *
  38  *   8.1.3. Server Response
  39  *
  40  *   It MAY also leave the RESPOND state for CLOSED after a timeout of
  41  *   not less than 4MSL (8 minutes);
  42  *
  43  * - PARTOPEN:
  44  *
  45  *   8.1.5. Handshake Completion
  46  *
  47  *   If the client remains in PARTOPEN for more than 4MSL (8 minutes),
  48  *   it SHOULD reset the connection with Reset Code 2, "Aborted".
  49  *
  50  * - OPEN:
  51  *
  52  *   The DCCP timestamp overflows after 11.9 hours. If the connection
  53  *   stays idle this long the sequence number won't be recognized
  54  *   as valid anymore.
  55  *
  56  * - CLOSEREQ/CLOSING:
  57  *
  58  *   8.3. Termination
  59  *
  60  *   The retransmission timer should initially be set to go off in two
  61  *   round-trip times and should back off to not less than once every
  62  *   64 seconds ...
  63  *
  64  * - TIMEWAIT:
  65  *
  66  *   4.3. States
  67  *
  68  *   A server or client socket remains in this state for 2MSL (4 minutes)
  69  *   after the connection has been town down, ...
  70  */
  71
  72 #define DCCP_MSL (2 * 60 * HZ)
  73
  74 static const char * const dccp_state_names[] = {
  75         [CT_DCCP_NONE]          = "NONE",
  76         [CT_DCCP_REQUEST]       = "REQUEST",
  77         [CT_DCCP_RESPOND]       = "RESPOND",
  78         [CT_DCCP_PARTOPEN]      = "PARTOPEN",
  79         [CT_DCCP_OPEN]          = "OPEN",
  80         [CT_DCCP_CLOSEREQ]      = "CLOSEREQ",
  81         [CT_DCCP_CLOSING]       = "CLOSING",
  82         [CT_DCCP_TIMEWAIT]      = "TIMEWAIT",
  83         [CT_DCCP_IGNORE]        = "IGNORE",
  84         [CT_DCCP_INVALID]       = "INVALID",
  85 };
  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 /*
  99  * DCCP state transistion table
 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 */
 245                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 246                 },
 247                 [DCCP_PKT_SYNCACK] = {
 248                 /*
 249                  * We currently ignore SyncAck packets
 250                  *
 251                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 252                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 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 */
 373                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 374                 },
 375                 [DCCP_PKT_SYNCACK] = {
 376                 /*
 377                  * We currently ignore SyncAck packets
 378                  *
 379                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 380                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 381                 },
 382         },
 383 };
 384
 385 /* this module per-net specifics */
 386 static int dccp_net_id;
 387 struct dccp_net {
 388         int dccp_loose;
 389         unsigned int dccp_timeout[CT_DCCP_MAX + 1];
 390 #ifdef CONFIG_SYSCTL
 391         struct ctl_table_header *sysctl_header;
 392         struct ctl_table *sysctl_table;
 393 #endif
 394 };
 395
 396 static inline struct dccp_net *dccp_pernet(struct net *net)
 397 {
 398         return net_generic(net, dccp_net_id);
 399 }
 400
 401 static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 402                               struct nf_conntrack_tuple *tuple)
 403 {
 404         struct dccp_hdr _hdr, *dh;
 405
 406         dh = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 407         if (dh == NULL)
 408                 return false;
 409
 410         tuple->src.u.dccp.port = dh->dccph_sport;
 411         tuple->dst.u.dccp.port = dh->dccph_dport;
 412         return true;
 413 }
 414
 415 static bool dccp_invert_tuple(struct nf_conntrack_tuple *inv,
 416                               const struct nf_conntrack_tuple *tuple)
 417 {
 418         inv->src.u.dccp.port = tuple->dst.u.dccp.port;
 419         inv->dst.u.dccp.port = tuple->src.u.dccp.port;
 420         return true;
 421 }
 422
 423 static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb,
 424                      unsigned int dataoff)
 425 {
 426         struct net *net = nf_ct_net(ct);
 427         struct dccp_net *dn;
 428         struct dccp_hdr _dh, *dh;
 429         const char *msg;
 430         u_int8_t state;
 431
 432         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 433         BUG_ON(dh == NULL);
 434
 435         state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE];
 436         switch (state) {
 437         default:
 438                 dn = dccp_pernet(net);
 439                 if (dn->dccp_loose == 0) {
 440                         msg = "nf_ct_dccp: not picking up existing connection ";
 441                         goto out_invalid;
 442                 }
 443         case CT_DCCP_REQUEST:
 444                 break;
 445         case CT_DCCP_INVALID:
 446                 msg = "nf_ct_dccp: invalid state transition ";
 447                 goto out_invalid;
 448         }
 449
 450         ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 451         ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 452         ct->proto.dccp.state = CT_DCCP_NONE;
 453         return true;
 454
 455 out_invalid:
 456         if (LOG_INVALID(net, IPPROTO_DCCP))
 457                 nf_log_packet(nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL, msg);
 458         return false;
 459 }
 460
 461 static u64 dccp_ack_seq(const struct dccp_hdr *dh)
 462 {
 463         const struct dccp_hdr_ack_bits *dhack;
 464
 465         dhack = (void *)dh + __dccp_basic_hdr_len(dh);
 466         return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
 467                      ntohl(dhack->dccph_ack_nr_low);
 468 }
 469
 470 static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
 471                        unsigned int dataoff, enum ip_conntrack_info ctinfo,
 472                        u_int8_t pf, unsigned int hooknum)
 473 {
 474         struct net *net = nf_ct_net(ct);
 475         struct dccp_net *dn;
 476         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 477         struct dccp_hdr _dh, *dh;
 478         u_int8_t type, old_state, new_state;
 479         enum ct_dccp_roles role;
 480
 481         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 482         BUG_ON(dh == NULL);
 483         type = dh->dccph_type;
 484
 485         if (type == DCCP_PKT_RESET &&
 486             !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 487                 /* Tear down connection immediately if only reply is a RESET */
 488                 nf_ct_kill_acct(ct, ctinfo, skb);
 489                 return NF_ACCEPT;
 490         }
 491
 492         spin_lock_bh(&ct->lock);
 493
 494         role = ct->proto.dccp.role[dir];
 495         old_state = ct->proto.dccp.state;
 496         new_state = dccp_state_table[role][type][old_state];
 497
 498         switch (new_state) {
 499         case CT_DCCP_REQUEST:
 500                 if (old_state == CT_DCCP_TIMEWAIT &&
 501                     role == CT_DCCP_ROLE_SERVER) {
 502                         /* Reincarnation in the reverse direction: reopen and
 503                          * reverse client/server roles. */
 504                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT;
 505                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER;
 506                 }
 507                 break;
 508         case CT_DCCP_RESPOND:
 509                 if (old_state == CT_DCCP_REQUEST)
 510                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 511                 break;
 512         case CT_DCCP_PARTOPEN:
 513                 if (old_state == CT_DCCP_RESPOND &&
 514                     type == DCCP_PKT_ACK &&
 515                     dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq)
 516                         set_bit(IPS_ASSURED_BIT, &ct->status);
 517                 break;
 518         case CT_DCCP_IGNORE:
 519                 /*
 520                  * Connection tracking might be out of sync, so we ignore
 521                  * packets that might establish a new connection and resync
 522                  * if the server responds with a valid Response.
 523                  */
 524                 if (ct->proto.dccp.last_dir == !dir &&
 525                     ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST &&
 526                     type == DCCP_PKT_RESPONSE) {
 527                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT;
 528                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER;
 529                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 530                         new_state = CT_DCCP_RESPOND;
 531                         break;
 532                 }
 533                 ct->proto.dccp.last_dir = dir;
 534                 ct->proto.dccp.last_pkt = type;
 535
 536                 spin_unlock_bh(&ct->lock);
 537                 if (LOG_INVALID(net, IPPROTO_DCCP))
 538                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 539                                       "nf_ct_dccp: invalid packet ignored ");
 540                 return NF_ACCEPT;
 541         case CT_DCCP_INVALID:
 542                 spin_unlock_bh(&ct->lock);
 543                 if (LOG_INVALID(net, IPPROTO_DCCP))
 544                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 545                                       "nf_ct_dccp: invalid state transition ");
 546                 return -NF_ACCEPT;
 547         }
 548
 549         ct->proto.dccp.last_dir = dir;
 550         ct->proto.dccp.last_pkt = type;
 551         ct->proto.dccp.state = new_state;
 552         spin_unlock_bh(&ct->lock);
 553
 554         dn = dccp_pernet(net);
 555         nf_ct_refresh_acct(ct, ctinfo, skb, dn->dccp_timeout[new_state]);
 556
 557         return NF_ACCEPT;
 558 }
 559
 560 static int dccp_error(struct net *net, struct sk_buff *skb,
 561                       unsigned int dataoff, enum ip_conntrack_info *ctinfo,
 562                       u_int8_t pf, unsigned int hooknum)
 563 {
 564         struct dccp_hdr _dh, *dh;
 565         unsigned int dccp_len = skb->len - dataoff;
 566         unsigned int cscov;
 567         const char *msg;
 568
 569         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 570         if (dh == NULL) {
 571                 msg = "nf_ct_dccp: short packet ";
 572                 goto out_invalid;
 573         }
 574
 575         if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) ||
 576             dh->dccph_doff * 4 > dccp_len) {
 577                 msg = "nf_ct_dccp: truncated/malformed packet ";
 578                 goto out_invalid;
 579         }
 580
 581         cscov = dccp_len;
 582         if (dh->dccph_cscov) {
 583                 cscov = (dh->dccph_cscov - 1) * 4;
 584                 if (cscov > dccp_len) {
 585                         msg = "nf_ct_dccp: bad checksum coverage ";
 586                         goto out_invalid;
 587                 }
 588         }
 589
 590         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 591             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP,
 592                                 pf)) {
 593                 msg = "nf_ct_dccp: bad checksum ";
 594                 goto out_invalid;
 595         }
 596
 597         if (dh->dccph_type >= DCCP_PKT_INVALID) {
 598                 msg = "nf_ct_dccp: reserved packet type ";
 599                 goto out_invalid;
 600         }
 601
 602         return NF_ACCEPT;
 603
 604 out_invalid:
 605         if (LOG_INVALID(net, IPPROTO_DCCP))
 606                 nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg);
 607         return -NF_ACCEPT;
 608 }
 609
 610 static int dccp_print_tuple(struct seq_file *s,
 611                             const struct nf_conntrack_tuple *tuple)
 612 {
 613         return seq_printf(s, "sport=%hu dport=%hu ",
 614                           ntohs(tuple->src.u.dccp.port),
 615                           ntohs(tuple->dst.u.dccp.port));
 616 }
 617
 618 static int dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 619 {
 620         return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
 621 }
 622
 623 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 624 static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 625                           struct nf_conn *ct)
 626 {
 627         struct nlattr *nest_parms;
 628
 629         spin_lock_bh(&ct->lock);
 630         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
 631         if (!nest_parms)
 632                 goto nla_put_failure;
 633         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state);
 634         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_ROLE,
 635                    ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]);
 636         NLA_PUT_BE64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ,
 637                      cpu_to_be64(ct->proto.dccp.handshake_seq));
 638         nla_nest_end(skb, nest_parms);
 639         spin_unlock_bh(&ct->lock);
 640         return 0;
 641
 642 nla_put_failure:
 643         spin_unlock_bh(&ct->lock);
 644         return -1;
 645 }
 646
 647 static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
 648         [CTA_PROTOINFO_DCCP_STATE]      = { .type = NLA_U8 },
 649         [CTA_PROTOINFO_DCCP_ROLE]       = { .type = NLA_U8 },
 650         [CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 },
 651 };
 652
 653 static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
 654 {
 655         struct nlattr *attr = cda[CTA_PROTOINFO_DCCP];
 656         struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1];
 657         int err;
 658
 659         if (!attr)
 660                 return 0;
 661
 662         err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr,
 663                                dccp_nla_policy);
 664         if (err < 0)
 665                 return err;
 666
 667         if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
 668             !tb[CTA_PROTOINFO_DCCP_ROLE] ||
 669             nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX ||
 670             nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) {
 671                 return -EINVAL;
 672         }
 673
 674         spin_lock_bh(&ct->lock);
 675         ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
 676         if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) {
 677                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 678                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 679         } else {
 680                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
 681                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
 682         }
 683         if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) {
 684                 ct->proto.dccp.handshake_seq =
 685                 be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]));
 686         }
 687         spin_unlock_bh(&ct->lock);
 688         return 0;
 689 }
 690
 691 static int dccp_nlattr_size(void)
 692 {
 693         return nla_total_size(0)        /* CTA_PROTOINFO_DCCP */
 694                 + nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
 695 }
 696 #endif
 697
 698 #ifdef CONFIG_SYSCTL
 699 /* template, data assigned later */
 700 static struct ctl_table dccp_sysctl_table[] = {
 701         {
 702                 .ctl_name       = CTL_UNNUMBERED,
 703                 .procname       = "nf_conntrack_dccp_timeout_request",
 704                 .maxlen         = sizeof(unsigned int),
 705                 .mode           = 0644,
 706                 .proc_handler   = proc_dointvec_jiffies,
 707         },
 708         {
 709                 .ctl_name       = CTL_UNNUMBERED,
 710                 .procname       = "nf_conntrack_dccp_timeout_respond",
 711                 .maxlen         = sizeof(unsigned int),
 712                 .mode           = 0644,
 713                 .proc_handler   = proc_dointvec_jiffies,
 714         },
 715         {
 716                 .ctl_name       = CTL_UNNUMBERED,
 717                 .procname       = "nf_conntrack_dccp_timeout_partopen",
 718                 .maxlen         = sizeof(unsigned int),
 719                 .mode           = 0644,
 720                 .proc_handler   = proc_dointvec_jiffies,
 721         },
 722         {
 723                 .ctl_name       = CTL_UNNUMBERED,
 724                 .procname       = "nf_conntrack_dccp_timeout_open",
 725                 .maxlen         = sizeof(unsigned int),
 726                 .mode           = 0644,
 727                 .proc_handler   = proc_dointvec_jiffies,
 728         },
 729         {
 730                 .ctl_name       = CTL_UNNUMBERED,
 731                 .procname       = "nf_conntrack_dccp_timeout_closereq",
 732                 .maxlen         = sizeof(unsigned int),
 733                 .mode           = 0644,
 734                 .proc_handler   = proc_dointvec_jiffies,
 735         },
 736         {
 737                 .ctl_name       = CTL_UNNUMBERED,
 738                 .procname       = "nf_conntrack_dccp_timeout_closing",
 739                 .maxlen         = sizeof(unsigned int),
 740                 .mode           = 0644,
 741                 .proc_handler   = proc_dointvec_jiffies,
 742         },
 743         {
 744                 .ctl_name       = CTL_UNNUMBERED,
 745                 .procname       = "nf_conntrack_dccp_timeout_timewait",
 746                 .maxlen         = sizeof(unsigned int),
 747                 .mode           = 0644,
 748                 .proc_handler   = proc_dointvec_jiffies,
 749         },
 750         {
 751                 .ctl_name       = CTL_UNNUMBERED,
 752                 .procname       = "nf_conntrack_dccp_loose",
 753                 .maxlen         = sizeof(int),
 754                 .mode           = 0644,
 755                 .proc_handler   = proc_dointvec,
 756         },
 757         {
 758                 .ctl_name       = 0,
 759         }
 760 };
 761 #endif /* CONFIG_SYSCTL */
 762
 763 static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = {
 764         .l3proto                = AF_INET,
 765         .l4proto                = IPPROTO_DCCP,
 766         .name                   = "dccp",
 767         .pkt_to_tuple           = dccp_pkt_to_tuple,
 768         .invert_tuple           = dccp_invert_tuple,
 769         .new                    = dccp_new,
 770         .packet                 = dccp_packet,
 771         .error                  = dccp_error,
 772         .print_tuple            = dccp_print_tuple,
 773         .print_conntrack        = dccp_print_conntrack,
 774 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 775         .to_nlattr              = dccp_to_nlattr,
 776         .nlattr_size            = dccp_nlattr_size,
 777         .from_nlattr            = nlattr_to_dccp,
 778         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 779         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 780         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 781         .nla_policy             = nf_ct_port_nla_policy,
 782 #endif
 783 };
 784
 785 static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = {
 786         .l3proto                = AF_INET6,
 787         .l4proto                = IPPROTO_DCCP,
 788         .name                   = "dccp",
 789         .pkt_to_tuple           = dccp_pkt_to_tuple,
 790         .invert_tuple           = dccp_invert_tuple,
 791         .new                    = dccp_new,
 792         .packet                 = dccp_packet,
 793         .error                  = dccp_error,
 794         .print_tuple            = dccp_print_tuple,
 795         .print_conntrack        = dccp_print_conntrack,
 796 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 797         .to_nlattr              = dccp_to_nlattr,
 798         .nlattr_size            = dccp_nlattr_size,
 799         .from_nlattr            = nlattr_to_dccp,
 800         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 801         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 802         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 803         .nla_policy             = nf_ct_port_nla_policy,
 804 #endif
 805 };
 806
 807 static __net_init int dccp_net_init(struct net *net)
 808 {
 809         struct dccp_net *dn;
 810         int err;
 811
 812         dn = kmalloc(sizeof(*dn), GFP_KERNEL);
 813         if (!dn)
 814                 return -ENOMEM;
 815
 816         /* default values */
 817         dn->dccp_loose = 1;
 818         dn->dccp_timeout[CT_DCCP_REQUEST]       = 2 * DCCP_MSL;
 819         dn->dccp_timeout[CT_DCCP_RESPOND]       = 4 * DCCP_MSL;
 820         dn->dccp_timeout[CT_DCCP_PARTOPEN]      = 4 * DCCP_MSL;
 821         dn->dccp_timeout[CT_DCCP_OPEN]          = 12 * 3600 * HZ;
 822         dn->dccp_timeout[CT_DCCP_CLOSEREQ]      = 64 * HZ;
 823         dn->dccp_timeout[CT_DCCP_CLOSING]       = 64 * HZ;
 824         dn->dccp_timeout[CT_DCCP_TIMEWAIT]      = 2 * DCCP_MSL;
 825
 826         err = net_assign_generic(net, dccp_net_id, dn);
 827         if (err)
 828                 goto out;
 829
 830 #ifdef CONFIG_SYSCTL
 831         err = -ENOMEM;
 832         dn->sysctl_table = kmemdup(dccp_sysctl_table,
 833                         sizeof(dccp_sysctl_table), GFP_KERNEL);
 834         if (!dn->sysctl_table)
 835                 goto out;
 836
 837         dn->sysctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST];
 838         dn->sysctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND];
 839         dn->sysctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN];
 840         dn->sysctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN];
 841         dn->sysctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ];
 842         dn->sysctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
 843         dn->sysctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
 844         dn->sysctl_table[7].data = &dn->dccp_loose;
 845
 846         dn->sysctl_header = register_net_sysctl_table(net,
 847                         nf_net_netfilter_sysctl_path, dn->sysctl_table);
 848         if (!dn->sysctl_header) {
 849                 kfree(dn->sysctl_table);
 850                 goto out;
 851         }
 852 #endif
 853
 854         return 0;
 855
 856 out:
 857         kfree(dn);
 858         return err;
 859 }
 860
 861 static __net_exit void dccp_net_exit(struct net *net)
 862 {
 863         struct dccp_net *dn = dccp_pernet(net);
 864 #ifdef CONFIG_SYSCTL
 865         unregister_net_sysctl_table(dn->sysctl_header);
 866         kfree(dn->sysctl_table);
 867 #endif
 868         kfree(dn);
 869
 870         net_assign_generic(net, dccp_net_id, NULL);
 871 }
 872
 873 static struct pernet_operations dccp_net_ops = {
 874         .init = dccp_net_init,
 875         .exit = dccp_net_exit,
 876 };
 877
 878 static int __init nf_conntrack_proto_dccp_init(void)
 879 {
 880         int err;
 881
 882         err = register_pernet_gen_subsys(&dccp_net_id, &dccp_net_ops);
 883         if (err < 0)
 884                 goto err1;
 885
 886         err = nf_conntrack_l4proto_register(&dccp_proto4);
 887         if (err < 0)
 888                 goto err2;
 889
 890         err = nf_conntrack_l4proto_register(&dccp_proto6);
 891         if (err < 0)
 892                 goto err3;
 893         return 0;
 894
 895 err3:
 896         nf_conntrack_l4proto_unregister(&dccp_proto4);
 897 err2:
 898         unregister_pernet_gen_subsys(dccp_net_id, &dccp_net_ops);
 899 err1:
 900         return err;
 901 }
 902
 903 static void __exit nf_conntrack_proto_dccp_fini(void)
 904 {
 905         unregister_pernet_gen_subsys(dccp_net_id, &dccp_net_ops);
 906         nf_conntrack_l4proto_unregister(&dccp_proto6);
 907         nf_conntrack_l4proto_unregister(&dccp_proto4);
 908 }
 909
 910 module_init(nf_conntrack_proto_dccp_init);
 911 module_exit(nf_conntrack_proto_dccp_fini);
 912
 913 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 914 MODULE_DESCRIPTION("DCCP connection tracking protocol helper");
 915 MODULE_LICENSE("GPL");