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 static DEFINE_RWLOCK(dccp_lock);
  28
  29 /* Timeouts are based on values from RFC4340:
  30  *
  31  * - REQUEST:
  32  *
  33  *   8.1.2. Client Request
  34  *
  35  *   A client MAY give up on its DCCP-Requests after some time
  36  *   (3 minutes, for example).
  37  *
  38  * - RESPOND:
  39  *
  40  *   8.1.3. Server Response
  41  *
  42  *   It MAY also leave the RESPOND state for CLOSED after a timeout of
  43  *   not less than 4MSL (8 minutes);
  44  *
  45  * - PARTOPEN:
  46  *
  47  *   8.1.5. Handshake Completion
  48  *
  49  *   If the client remains in PARTOPEN for more than 4MSL (8 minutes),
  50  *   it SHOULD reset the connection with Reset Code 2, "Aborted".
  51  *
  52  * - OPEN:
  53  *
  54  *   The DCCP timestamp overflows after 11.9 hours. If the connection
  55  *   stays idle this long the sequence number won't be recognized
  56  *   as valid anymore.
  57  *
  58  * - CLOSEREQ/CLOSING:
  59  *
  60  *   8.3. Termination
  61  *
  62  *   The retransmission timer should initially be set to go off in two
  63  *   round-trip times and should back off to not less than once every
  64  *   64 seconds ...
  65  *
  66  * - TIMEWAIT:
  67  *
  68  *   4.3. States
  69  *
  70  *   A server or client socket remains in this state for 2MSL (4 minutes)
  71  *   after the connection has been town down, ...
  72  */
  73
  74 #define DCCP_MSL (2 * 60 * HZ)
  75
  76 static const char * const dccp_state_names[] = {
  77         [CT_DCCP_NONE]          = "NONE",
  78         [CT_DCCP_REQUEST]       = "REQUEST",
  79         [CT_DCCP_RESPOND]       = "RESPOND",
  80         [CT_DCCP_PARTOPEN]      = "PARTOPEN",
  81         [CT_DCCP_OPEN]          = "OPEN",
  82         [CT_DCCP_CLOSEREQ]      = "CLOSEREQ",
  83         [CT_DCCP_CLOSING]       = "CLOSING",
  84         [CT_DCCP_TIMEWAIT]      = "TIMEWAIT",
  85         [CT_DCCP_IGNORE]        = "IGNORE",
  86         [CT_DCCP_INVALID]       = "INVALID",
  87 };
  88
  89 #define sNO     CT_DCCP_NONE
  90 #define sRQ     CT_DCCP_REQUEST
  91 #define sRS     CT_DCCP_RESPOND
  92 #define sPO     CT_DCCP_PARTOPEN
  93 #define sOP     CT_DCCP_OPEN
  94 #define sCR     CT_DCCP_CLOSEREQ
  95 #define sCG     CT_DCCP_CLOSING
  96 #define sTW     CT_DCCP_TIMEWAIT
  97 #define sIG     CT_DCCP_IGNORE
  98 #define sIV     CT_DCCP_INVALID
  99
 100 /*
 101  * DCCP state transistion table
 102  *
 103  * The assumption is the same as for TCP tracking:
 104  *
 105  * We are the man in the middle. All the packets go through us but might
 106  * get lost in transit to the destination. It is assumed that the destination
 107  * can't receive segments we haven't seen.
 108  *
 109  * The following states exist:
 110  *
 111  * NONE:        Initial state, expecting Request
 112  * REQUEST:     Request seen, waiting for Response from server
 113  * RESPOND:     Response from server seen, waiting for Ack from client
 114  * PARTOPEN:    Ack after Response seen, waiting for packet other than Response,
 115  *              Reset or Sync from server
 116  * OPEN:        Packet other than Response, Reset or Sync seen
 117  * CLOSEREQ:    CloseReq from server seen, expecting Close from client
 118  * CLOSING:     Close seen, expecting Reset
 119  * TIMEWAIT:    Reset seen
 120  * IGNORE:      Not determinable whether packet is valid
 121  *
 122  * Some states exist only on one side of the connection: REQUEST, RESPOND,
 123  * PARTOPEN, CLOSEREQ. For the other side these states are equivalent to
 124  * the one it was in before.
 125  *
 126  * Packets are marked as ignored (sIG) if we don't know if they're valid
 127  * (for example a reincarnation of a connection we didn't notice is dead
 128  * already) and the server may send back a connection closing Reset or a
 129  * Response. They're also used for Sync/SyncAck packets, which we don't
 130  * care about.
 131  */
 132 static const u_int8_t
 133 dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = {
 134         [CT_DCCP_ROLE_CLIENT] = {
 135                 [DCCP_PKT_REQUEST] = {
 136                 /*
 137                  * sNO -> sRQ           Regular Request
 138                  * sRQ -> sRQ           Retransmitted Request or reincarnation
 139                  * sRS -> sRS           Retransmitted Request (apparently Response
 140                  *                      got lost after we saw it) or reincarnation
 141                  * sPO -> sIG           Ignore, conntrack might be out of sync
 142                  * sOP -> sIG           Ignore, conntrack might be out of sync
 143                  * sCR -> sIG           Ignore, conntrack might be out of sync
 144                  * sCG -> sIG           Ignore, conntrack might be out of sync
 145                  * sTW -> sRQ           Reincarnation
 146                  *
 147                  *      sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */
 148                         sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ,
 149                 },
 150                 [DCCP_PKT_RESPONSE] = {
 151                 /*
 152                  * sNO -> sIV           Invalid
 153                  * sRQ -> sIG           Ignore, might be response to ignored Request
 154                  * sRS -> sIG           Ignore, might be response to ignored Request
 155                  * sPO -> sIG           Ignore, might be response to ignored Request
 156                  * sOP -> sIG           Ignore, might be response to ignored Request
 157                  * sCR -> sIG           Ignore, might be response to ignored Request
 158                  * sCG -> sIG           Ignore, might be response to ignored Request
 159                  * sTW -> sIV           Invalid, reincarnation in reverse direction
 160                  *                      goes through sRQ
 161                  *
 162                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 163                         sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV,
 164                 },
 165                 [DCCP_PKT_ACK] = {
 166                 /*
 167                  * sNO -> sIV           No connection
 168                  * sRQ -> sIV           No connection
 169                  * sRS -> sPO           Ack for Response, move to PARTOPEN (8.1.5.)
 170                  * sPO -> sPO           Retransmitted Ack for Response, remain in PARTOPEN
 171                  * sOP -> sOP           Regular ACK, remain in OPEN
 172                  * sCR -> sCR           Ack in CLOSEREQ MAY be processed (8.3.)
 173                  * sCG -> sCG           Ack in CLOSING MAY be processed (8.3.)
 174                  * sTW -> sIV
 175                  *
 176                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 177                         sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
 178                 },
 179                 [DCCP_PKT_DATA] = {
 180                 /*
 181                  * sNO -> sIV           No connection
 182                  * sRQ -> sIV           No connection
 183                  * sRS -> sIV           No connection
 184                  * sPO -> sIV           MUST use DataAck in PARTOPEN state (8.1.5.)
 185                  * sOP -> sOP           Regular Data packet
 186                  * sCR -> sCR           Data in CLOSEREQ MAY be processed (8.3.)
 187                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 188                  * sTW -> sIV
 189                  *
 190                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 191                         sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV,
 192                 },
 193                 [DCCP_PKT_DATAACK] = {
 194                 /*
 195                  * sNO -> sIV           No connection
 196                  * sRQ -> sIV           No connection
 197                  * sRS -> sPO           Ack for Response, move to PARTOPEN (8.1.5.)
 198                  * sPO -> sPO           Remain in PARTOPEN state
 199                  * sOP -> sOP           Regular DataAck packet in OPEN state
 200                  * sCR -> sCR           DataAck in CLOSEREQ MAY be processed (8.3.)
 201                  * sCG -> sCG           DataAck in CLOSING MAY be processed (8.3.)
 202                  * sTW -> sIV
 203                  *
 204                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 205                         sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
 206                 },
 207                 [DCCP_PKT_CLOSEREQ] = {
 208                 /*
 209                  * CLOSEREQ may only be sent by the server.
 210                  *
 211                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 212                         sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV
 213                 },
 214                 [DCCP_PKT_CLOSE] = {
 215                 /*
 216                  * sNO -> sIV           No connection
 217                  * sRQ -> sIV           No connection
 218                  * sRS -> sIV           No connection
 219                  * sPO -> sCG           Client-initiated close
 220                  * sOP -> sCG           Client-initiated close
 221                  * sCR -> sCG           Close in response to CloseReq (8.3.)
 222                  * sCG -> sCG           Retransmit
 223                  * sTW -> sIV           Late retransmit, already in TIME_WAIT
 224                  *
 225                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 226                         sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV
 227                 },
 228                 [DCCP_PKT_RESET] = {
 229                 /*
 230                  * sNO -> sIV           No connection
 231                  * sRQ -> sTW           Sync received or timeout, SHOULD send Reset (8.1.1.)
 232                  * sRS -> sTW           Response received without Request
 233                  * sPO -> sTW           Timeout, SHOULD send Reset (8.1.5.)
 234                  * sOP -> sTW           Connection reset
 235                  * sCR -> sTW           Connection reset
 236                  * sCG -> sTW           Connection reset
 237                  * sTW -> sIG           Ignore (don't refresh timer)
 238                  *
 239                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 240                         sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG
 241                 },
 242                 [DCCP_PKT_SYNC] = {
 243                 /*
 244                  * We currently ignore Sync packets
 245                  *
 246                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 247                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 248                 },
 249                 [DCCP_PKT_SYNCACK] = {
 250                 /*
 251                  * We currently ignore SyncAck packets
 252                  *
 253                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 254                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 255                 },
 256         },
 257         [CT_DCCP_ROLE_SERVER] = {
 258                 [DCCP_PKT_REQUEST] = {
 259                 /*
 260                  * sNO -> sIV           Invalid
 261                  * sRQ -> sIG           Ignore, conntrack might be out of sync
 262                  * sRS -> sIG           Ignore, conntrack might be out of sync
 263                  * sPO -> sIG           Ignore, conntrack might be out of sync
 264                  * sOP -> sIG           Ignore, conntrack might be out of sync
 265                  * sCR -> sIG           Ignore, conntrack might be out of sync
 266                  * sCG -> sIG           Ignore, conntrack might be out of sync
 267                  * sTW -> sRQ           Reincarnation, must reverse roles
 268                  *
 269                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 270                         sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ
 271                 },
 272                 [DCCP_PKT_RESPONSE] = {
 273                 /*
 274                  * sNO -> sIV           Response without Request
 275                  * sRQ -> sRS           Response to clients Request
 276                  * sRS -> sRS           Retransmitted Response (8.1.3. SHOULD NOT)
 277                  * sPO -> sIG           Response to an ignored Request or late retransmit
 278                  * sOP -> sIG           Ignore, might be response to ignored Request
 279                  * sCR -> sIG           Ignore, might be response to ignored Request
 280                  * sCG -> sIG           Ignore, might be response to ignored Request
 281                  * sTW -> sIV           Invalid, Request from client in sTW moves to sRQ
 282                  *
 283                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 284                         sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV
 285                 },
 286                 [DCCP_PKT_ACK] = {
 287                 /*
 288                  * sNO -> sIV           No connection
 289                  * sRQ -> sIV           No connection
 290                  * sRS -> sIV           No connection
 291                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 292                  * sOP -> sOP           Regular Ack in OPEN state
 293                  * sCR -> sIV           Waiting for Close from client
 294                  * sCG -> sCG           Ack in CLOSING MAY be processed (8.3.)
 295                  * sTW -> sIV
 296                  *
 297                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 298                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 299                 },
 300                 [DCCP_PKT_DATA] = {
 301                 /*
 302                  * sNO -> sIV           No connection
 303                  * sRQ -> sIV           No connection
 304                  * sRS -> sIV           No connection
 305                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 306                  * sOP -> sOP           Regular Data packet in OPEN state
 307                  * sCR -> sIV           Waiting for Close from client
 308                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 309                  * sTW -> sIV
 310                  *
 311                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 312                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 313                 },
 314                 [DCCP_PKT_DATAACK] = {
 315                 /*
 316                  * sNO -> sIV           No connection
 317                  * sRQ -> sIV           No connection
 318                  * sRS -> sIV           No connection
 319                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 320                  * sOP -> sOP           Regular DataAck in OPEN state
 321                  * sCR -> sIV           Waiting for Close from client
 322                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 323                  * sTW -> sIV
 324                  *
 325                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 326                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 327                 },
 328                 [DCCP_PKT_CLOSEREQ] = {
 329                 /*
 330                  * sNO -> sIV           No connection
 331                  * sRQ -> sIV           No connection
 332                  * sRS -> sIV           No connection
 333                  * sPO -> sOP -> sCR    Move directly to CLOSEREQ (8.1.5.)
 334                  * sOP -> sCR           CloseReq in OPEN state
 335                  * sCR -> sCR           Retransmit
 336                  * sCG -> sCR           Simultaneous close, client sends another Close
 337                  * sTW -> sIV           Already closed
 338                  *
 339                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 340                         sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV
 341                 },
 342                 [DCCP_PKT_CLOSE] = {
 343                 /*
 344                  * sNO -> sIV           No connection
 345                  * sRQ -> sIV           No connection
 346                  * sRS -> sIV           No connection
 347                  * sPO -> sOP -> sCG    Move direcly to CLOSING
 348                  * sOP -> sCG           Move to CLOSING
 349                  * sCR -> sIV           Close after CloseReq is invalid
 350                  * sCG -> sCG           Retransmit
 351                  * sTW -> sIV           Already closed
 352                  *
 353                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 354                         sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV
 355                 },
 356                 [DCCP_PKT_RESET] = {
 357                 /*
 358                  * sNO -> sIV           No connection
 359                  * sRQ -> sTW           Reset in response to Request
 360                  * sRS -> sTW           Timeout, SHOULD send Reset (8.1.3.)
 361                  * sPO -> sTW           Timeout, SHOULD send Reset (8.1.3.)
 362                  * sOP -> sTW
 363                  * sCR -> sTW
 364                  * sCG -> sTW
 365                  * sTW -> sIG           Ignore (don't refresh timer)
 366                  *
 367                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */
 368                         sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG
 369                 },
 370                 [DCCP_PKT_SYNC] = {
 371                 /*
 372                  * We currently ignore Sync packets
 373                  *
 374                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 375                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 376                 },
 377                 [DCCP_PKT_SYNCACK] = {
 378                 /*
 379                  * We currently ignore SyncAck packets
 380                  *
 381                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 382                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 383                 },
 384         },
 385 };
 386
 387 /* this module per-net specifics */
 388 static int dccp_net_id;
 389 struct dccp_net {
 390         int dccp_loose;
 391         unsigned int dccp_timeout[CT_DCCP_MAX + 1];
 392 #ifdef CONFIG_SYSCTL
 393         struct ctl_table_header *sysctl_header;
 394         struct ctl_table *sysctl_table;
 395 #endif
 396 };
 397
 398 static inline struct dccp_net *dccp_pernet(struct net *net)
 399 {
 400         return net_generic(net, dccp_net_id);
 401 }
 402
 403 static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 404                               struct nf_conntrack_tuple *tuple)
 405 {
 406         struct dccp_hdr _hdr, *dh;
 407
 408         dh = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 409         if (dh == NULL)
 410                 return false;
 411
 412         tuple->src.u.dccp.port = dh->dccph_sport;
 413         tuple->dst.u.dccp.port = dh->dccph_dport;
 414         return true;
 415 }
 416
 417 static bool dccp_invert_tuple(struct nf_conntrack_tuple *inv,
 418                               const struct nf_conntrack_tuple *tuple)
 419 {
 420         inv->src.u.dccp.port = tuple->dst.u.dccp.port;
 421         inv->dst.u.dccp.port = tuple->src.u.dccp.port;
 422         return true;
 423 }
 424
 425 static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb,
 426                      unsigned int dataoff)
 427 {
 428         struct net *net = nf_ct_net(ct);
 429         struct dccp_net *dn;
 430         struct dccp_hdr _dh, *dh;
 431         const char *msg;
 432         u_int8_t state;
 433
 434         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 435         BUG_ON(dh == NULL);
 436
 437         state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE];
 438         switch (state) {
 439         default:
 440                 dn = dccp_pernet(net);
 441                 if (dn->dccp_loose == 0) {
 442                         msg = "nf_ct_dccp: not picking up existing connection ";
 443                         goto out_invalid;
 444                 }
 445         case CT_DCCP_REQUEST:
 446                 break;
 447         case CT_DCCP_INVALID:
 448                 msg = "nf_ct_dccp: invalid state transition ";
 449                 goto out_invalid;
 450         }
 451
 452         ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 453         ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 454         ct->proto.dccp.state = CT_DCCP_NONE;
 455         return true;
 456
 457 out_invalid:
 458         if (LOG_INVALID(net, IPPROTO_DCCP))
 459                 nf_log_packet(nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL, msg);
 460         return false;
 461 }
 462
 463 static u64 dccp_ack_seq(const struct dccp_hdr *dh)
 464 {
 465         const struct dccp_hdr_ack_bits *dhack;
 466
 467         dhack = (void *)dh + __dccp_basic_hdr_len(dh);
 468         return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
 469                      ntohl(dhack->dccph_ack_nr_low);
 470 }
 471
 472 static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
 473                        unsigned int dataoff, enum ip_conntrack_info ctinfo,
 474                        u_int8_t pf, unsigned int hooknum)
 475 {
 476         struct net *net = nf_ct_net(ct);
 477         struct dccp_net *dn;
 478         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 479         struct dccp_hdr _dh, *dh;
 480         u_int8_t type, old_state, new_state;
 481         enum ct_dccp_roles role;
 482
 483         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 484         BUG_ON(dh == NULL);
 485         type = dh->dccph_type;
 486
 487         if (type == DCCP_PKT_RESET &&
 488             !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 489                 /* Tear down connection immediately if only reply is a RESET */
 490                 nf_ct_kill_acct(ct, ctinfo, skb);
 491                 return NF_ACCEPT;
 492         }
 493
 494         write_lock_bh(&dccp_lock);
 495
 496         role = ct->proto.dccp.role[dir];
 497         old_state = ct->proto.dccp.state;
 498         new_state = dccp_state_table[role][type][old_state];
 499
 500         switch (new_state) {
 501         case CT_DCCP_REQUEST:
 502                 if (old_state == CT_DCCP_TIMEWAIT &&
 503                     role == CT_DCCP_ROLE_SERVER) {
 504                         /* Reincarnation in the reverse direction: reopen and
 505                          * reverse client/server roles. */
 506                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT;
 507                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER;
 508                 }
 509                 break;
 510         case CT_DCCP_RESPOND:
 511                 if (old_state == CT_DCCP_REQUEST)
 512                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 513                 break;
 514         case CT_DCCP_PARTOPEN:
 515                 if (old_state == CT_DCCP_RESPOND &&
 516                     type == DCCP_PKT_ACK &&
 517                     dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq)
 518                         set_bit(IPS_ASSURED_BIT, &ct->status);
 519                 break;
 520         case CT_DCCP_IGNORE:
 521                 /*
 522                  * Connection tracking might be out of sync, so we ignore
 523                  * packets that might establish a new connection and resync
 524                  * if the server responds with a valid Response.
 525                  */
 526                 if (ct->proto.dccp.last_dir == !dir &&
 527                     ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST &&
 528                     type == DCCP_PKT_RESPONSE) {
 529                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT;
 530                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER;
 531                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 532                         new_state = CT_DCCP_RESPOND;
 533                         break;
 534                 }
 535                 ct->proto.dccp.last_dir = dir;
 536                 ct->proto.dccp.last_pkt = type;
 537
 538                 write_unlock_bh(&dccp_lock);
 539                 if (LOG_INVALID(net, IPPROTO_DCCP))
 540                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 541                                       "nf_ct_dccp: invalid packet ignored ");
 542                 return NF_ACCEPT;
 543         case CT_DCCP_INVALID:
 544                 write_unlock_bh(&dccp_lock);
 545                 if (LOG_INVALID(net, IPPROTO_DCCP))
 546                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 547                                       "nf_ct_dccp: invalid state transition ");
 548                 return -NF_ACCEPT;
 549         }
 550
 551         ct->proto.dccp.last_dir = dir;
 552         ct->proto.dccp.last_pkt = type;
 553         ct->proto.dccp.state = new_state;
 554         write_unlock_bh(&dccp_lock);
 555
 556         dn = dccp_pernet(net);
 557         nf_ct_refresh_acct(ct, ctinfo, skb, dn->dccp_timeout[new_state]);
 558
 559         return NF_ACCEPT;
 560 }
 561
 562 static int dccp_error(struct net *net, struct sk_buff *skb,
 563                       unsigned int dataoff, enum ip_conntrack_info *ctinfo,
 564                       u_int8_t pf, unsigned int hooknum)
 565 {
 566         struct dccp_hdr _dh, *dh;
 567         unsigned int dccp_len = skb->len - dataoff;
 568         unsigned int cscov;
 569         const char *msg;
 570
 571         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 572         if (dh == NULL) {
 573                 msg = "nf_ct_dccp: short packet ";
 574                 goto out_invalid;
 575         }
 576
 577         if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) ||
 578             dh->dccph_doff * 4 > dccp_len) {
 579                 msg = "nf_ct_dccp: truncated/malformed packet ";
 580                 goto out_invalid;
 581         }
 582
 583         cscov = dccp_len;
 584         if (dh->dccph_cscov) {
 585                 cscov = (dh->dccph_cscov - 1) * 4;
 586                 if (cscov > dccp_len) {
 587                         msg = "nf_ct_dccp: bad checksum coverage ";
 588                         goto out_invalid;
 589                 }
 590         }
 591
 592         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 593             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP,
 594                                 pf)) {
 595                 msg = "nf_ct_dccp: bad checksum ";
 596                 goto out_invalid;
 597         }
 598
 599         if (dh->dccph_type >= DCCP_PKT_INVALID) {
 600                 msg = "nf_ct_dccp: reserved packet type ";
 601                 goto out_invalid;
 602         }
 603
 604         return NF_ACCEPT;
 605
 606 out_invalid:
 607         if (LOG_INVALID(net, IPPROTO_DCCP))
 608                 nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg);
 609         return -NF_ACCEPT;
 610 }
 611
 612 static int dccp_print_tuple(struct seq_file *s,
 613                             const struct nf_conntrack_tuple *tuple)
 614 {
 615         return seq_printf(s, "sport=%hu dport=%hu ",
 616                           ntohs(tuple->src.u.dccp.port),
 617                           ntohs(tuple->dst.u.dccp.port));
 618 }
 619
 620 static int dccp_print_conntrack(struct seq_file *s, const struct nf_conn *ct)
 621 {
 622         return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
 623 }
 624
 625 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 626 static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 627                           const struct nf_conn *ct)
 628 {
 629         struct nlattr *nest_parms;
 630
 631         read_lock_bh(&dccp_lock);
 632         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
 633         if (!nest_parms)
 634                 goto nla_put_failure;
 635         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state);
 636         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_ROLE,
 637                    ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]);
 638         nla_nest_end(skb, nest_parms);
 639         read_unlock_bh(&dccp_lock);
 640         return 0;
 641
 642 nla_put_failure:
 643         read_unlock_bh(&dccp_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 };
 651
 652 static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
 653 {
 654         struct nlattr *attr = cda[CTA_PROTOINFO_DCCP];
 655         struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1];
 656         int err;
 657
 658         if (!attr)
 659                 return 0;
 660
 661         err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr,
 662                                dccp_nla_policy);
 663         if (err < 0)
 664                 return err;
 665
 666         if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
 667             !tb[CTA_PROTOINFO_DCCP_ROLE] ||
 668             nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX ||
 669             nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) {
 670                 return -EINVAL;
 671         }
 672
 673         write_lock_bh(&dccp_lock);
 674         ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
 675         if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) {
 676                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 677                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 678         } else {
 679                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
 680                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
 681         }
 682         write_unlock_bh(&dccp_lock);
 683         return 0;
 684 }
 685
 686 static int dccp_nlattr_size(void)
 687 {
 688         return nla_total_size(0)        /* CTA_PROTOINFO_DCCP */
 689                 + nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
 690 }
 691 #endif
 692
 693 #ifdef CONFIG_SYSCTL
 694 /* template, data assigned later */
 695 static struct ctl_table dccp_sysctl_table[] = {
 696         {
 697                 .ctl_name       = CTL_UNNUMBERED,
 698                 .procname       = "nf_conntrack_dccp_timeout_request",
 699                 .maxlen         = sizeof(unsigned int),
 700                 .mode           = 0644,
 701                 .proc_handler   = proc_dointvec_jiffies,
 702         },
 703         {
 704                 .ctl_name       = CTL_UNNUMBERED,
 705                 .procname       = "nf_conntrack_dccp_timeout_respond",
 706                 .maxlen         = sizeof(unsigned int),
 707                 .mode           = 0644,
 708                 .proc_handler   = proc_dointvec_jiffies,
 709         },
 710         {
 711                 .ctl_name       = CTL_UNNUMBERED,
 712                 .procname       = "nf_conntrack_dccp_timeout_partopen",
 713                 .maxlen         = sizeof(unsigned int),
 714                 .mode           = 0644,
 715                 .proc_handler   = proc_dointvec_jiffies,
 716         },
 717         {
 718                 .ctl_name       = CTL_UNNUMBERED,
 719                 .procname       = "nf_conntrack_dccp_timeout_open",
 720                 .maxlen         = sizeof(unsigned int),
 721                 .mode           = 0644,
 722                 .proc_handler   = proc_dointvec_jiffies,
 723         },
 724         {
 725                 .ctl_name       = CTL_UNNUMBERED,
 726                 .procname       = "nf_conntrack_dccp_timeout_closereq",
 727                 .maxlen         = sizeof(unsigned int),
 728                 .mode           = 0644,
 729                 .proc_handler   = proc_dointvec_jiffies,
 730         },
 731         {
 732                 .ctl_name       = CTL_UNNUMBERED,
 733                 .procname       = "nf_conntrack_dccp_timeout_closing",
 734                 .maxlen         = sizeof(unsigned int),
 735                 .mode           = 0644,
 736                 .proc_handler   = proc_dointvec_jiffies,
 737         },
 738         {
 739                 .ctl_name       = CTL_UNNUMBERED,
 740                 .procname       = "nf_conntrack_dccp_timeout_timewait",
 741                 .maxlen         = sizeof(unsigned int),
 742                 .mode           = 0644,
 743                 .proc_handler   = proc_dointvec_jiffies,
 744         },
 745         {
 746                 .ctl_name       = CTL_UNNUMBERED,
 747                 .procname       = "nf_conntrack_dccp_loose",
 748                 .maxlen         = sizeof(int),
 749                 .mode           = 0644,
 750                 .proc_handler   = proc_dointvec,
 751         },
 752         {
 753                 .ctl_name       = 0,
 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;
 805         int err;
 806
 807         dn = kmalloc(sizeof(*dn), GFP_KERNEL);
 808         if (!dn)
 809                 return -ENOMEM;
 810
 811         /* default values */
 812         dn->dccp_loose = 1;
 813         dn->dccp_timeout[CT_DCCP_REQUEST]       = 2 * DCCP_MSL;
 814         dn->dccp_timeout[CT_DCCP_RESPOND]       = 4 * DCCP_MSL;
 815         dn->dccp_timeout[CT_DCCP_PARTOPEN]      = 4 * DCCP_MSL;
 816         dn->dccp_timeout[CT_DCCP_OPEN]          = 12 * 3600 * HZ;
 817         dn->dccp_timeout[CT_DCCP_CLOSEREQ]      = 64 * HZ;
 818         dn->dccp_timeout[CT_DCCP_CLOSING]       = 64 * HZ;
 819         dn->dccp_timeout[CT_DCCP_TIMEWAIT]      = 2 * DCCP_MSL;
 820
 821         err = net_assign_generic(net, dccp_net_id, dn);
 822         if (err)
 823                 goto out;
 824
 825 #ifdef CONFIG_SYSCTL
 826         err = -ENOMEM;
 827         dn->sysctl_table = kmemdup(dccp_sysctl_table,
 828                         sizeof(dccp_sysctl_table), GFP_KERNEL);
 829         if (!dn->sysctl_table)
 830                 goto out;
 831
 832         dn->sysctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST];
 833         dn->sysctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND];
 834         dn->sysctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN];
 835         dn->sysctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN];
 836         dn->sysctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ];
 837         dn->sysctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
 838         dn->sysctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
 839         dn->sysctl_table[7].data = &dn->dccp_loose;
 840
 841         dn->sysctl_header = register_net_sysctl_table(net,
 842                         nf_net_netfilter_sysctl_path, dn->sysctl_table);
 843         if (!dn->sysctl_header) {
 844                 kfree(dn->sysctl_table);
 845                 goto out;
 846         }
 847 #endif
 848
 849         return 0;
 850
 851 out:
 852         kfree(dn);
 853         return err;
 854 }
 855
 856 static __net_exit void dccp_net_exit(struct net *net)
 857 {
 858         struct dccp_net *dn = dccp_pernet(net);
 859 #ifdef CONFIG_SYSCTL
 860         unregister_net_sysctl_table(dn->sysctl_header);
 861         kfree(dn->sysctl_table);
 862 #endif
 863         kfree(dn);
 864
 865         net_assign_generic(net, dccp_net_id, NULL);
 866 }
 867
 868 static struct pernet_operations dccp_net_ops = {
 869         .init = dccp_net_init,
 870         .exit = dccp_net_exit,
 871 };
 872
 873 static int __init nf_conntrack_proto_dccp_init(void)
 874 {
 875         int err;
 876
 877         err = register_pernet_gen_subsys(&dccp_net_id, &dccp_net_ops);
 878         if (err < 0)
 879                 goto err1;
 880
 881         err = nf_conntrack_l4proto_register(&dccp_proto4);
 882         if (err < 0)
 883                 goto err2;
 884
 885         err = nf_conntrack_l4proto_register(&dccp_proto6);
 886         if (err < 0)
 887                 goto err3;
 888         return 0;
 889
 890 err3:
 891         nf_conntrack_l4proto_unregister(&dccp_proto4);
 892 err2:
 893         unregister_pernet_gen_subsys(dccp_net_id, &dccp_net_ops);
 894 err1:
 895         return err;
 896 }
 897
 898 static void __exit nf_conntrack_proto_dccp_fini(void)
 899 {
 900         unregister_pernet_gen_subsys(dccp_net_id, &dccp_net_ops);
 901         nf_conntrack_l4proto_unregister(&dccp_proto6);
 902         nf_conntrack_l4proto_unregister(&dccp_proto4);
 903 }
 904
 905 module_init(nf_conntrack_proto_dccp_init);
 906 module_exit(nf_conntrack_proto_dccp_fini);
 907
 908 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 909 MODULE_DESCRIPTION("DCCP connection tracking protocol helper");
 910 MODULE_LICENSE("GPL");