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 static DEFINE_RWLOCK(dccp_lock);
  29
  30 /* Timeouts are based on values from RFC4340:
  31  *
  32  * - REQUEST:
  33  *
  34  *   8.1.2. Client Request
  35  *
  36  *   A client MAY give up on its DCCP-Requests after some time
  37  *   (3 minutes, for example).
  38  *
  39  * - RESPOND:
  40  *
  41  *   8.1.3. Server Response
  42  *
  43  *   It MAY also leave the RESPOND state for CLOSED after a timeout of
  44  *   not less than 4MSL (8 minutes);
  45  *
  46  * - PARTOPEN:
  47  *
  48  *   8.1.5. Handshake Completion
  49  *
  50  *   If the client remains in PARTOPEN for more than 4MSL (8 minutes),
  51  *   it SHOULD reset the connection with Reset Code 2, "Aborted".
  52  *
  53  * - OPEN:
  54  *
  55  *   The DCCP timestamp overflows after 11.9 hours. If the connection
  56  *   stays idle this long the sequence number won't be recognized
  57  *   as valid anymore.
  58  *
  59  * - CLOSEREQ/CLOSING:
  60  *
  61  *   8.3. Termination
  62  *
  63  *   The retransmission timer should initially be set to go off in two
  64  *   round-trip times and should back off to not less than once every
  65  *   64 seconds ...
  66  *
  67  * - TIMEWAIT:
  68  *
  69  *   4.3. States
  70  *
  71  *   A server or client socket remains in this state for 2MSL (4 minutes)
  72  *   after the connection has been town down, ...
  73  */
  74
  75 #define DCCP_MSL (2 * 60 * HZ)
  76
  77 static const char * const dccp_state_names[] = {
  78         [CT_DCCP_NONE]          = "NONE",
  79         [CT_DCCP_REQUEST]       = "REQUEST",
  80         [CT_DCCP_RESPOND]       = "RESPOND",
  81         [CT_DCCP_PARTOPEN]      = "PARTOPEN",
  82         [CT_DCCP_OPEN]          = "OPEN",
  83         [CT_DCCP_CLOSEREQ]      = "CLOSEREQ",
  84         [CT_DCCP_CLOSING]       = "CLOSING",
  85         [CT_DCCP_TIMEWAIT]      = "TIMEWAIT",
  86         [CT_DCCP_IGNORE]        = "IGNORE",
  87         [CT_DCCP_INVALID]       = "INVALID",
  88 };
  89
  90 #define sNO     CT_DCCP_NONE
  91 #define sRQ     CT_DCCP_REQUEST
  92 #define sRS     CT_DCCP_RESPOND
  93 #define sPO     CT_DCCP_PARTOPEN
  94 #define sOP     CT_DCCP_OPEN
  95 #define sCR     CT_DCCP_CLOSEREQ
  96 #define sCG     CT_DCCP_CLOSING
  97 #define sTW     CT_DCCP_TIMEWAIT
  98 #define sIG     CT_DCCP_IGNORE
  99 #define sIV     CT_DCCP_INVALID
 100
 101 /*
 102  * DCCP state transistion table
 103  *
 104  * The assumption is the same as for TCP tracking:
 105  *
 106  * We are the man in the middle. All the packets go through us but might
 107  * get lost in transit to the destination. It is assumed that the destination
 108  * can't receive segments we haven't seen.
 109  *
 110  * The following states exist:
 111  *
 112  * NONE:        Initial state, expecting Request
 113  * REQUEST:     Request seen, waiting for Response from server
 114  * RESPOND:     Response from server seen, waiting for Ack from client
 115  * PARTOPEN:    Ack after Response seen, waiting for packet other than Response,
 116  *              Reset or Sync from server
 117  * OPEN:        Packet other than Response, Reset or Sync seen
 118  * CLOSEREQ:    CloseReq from server seen, expecting Close from client
 119  * CLOSING:     Close seen, expecting Reset
 120  * TIMEWAIT:    Reset seen
 121  * IGNORE:      Not determinable whether packet is valid
 122  *
 123  * Some states exist only on one side of the connection: REQUEST, RESPOND,
 124  * PARTOPEN, CLOSEREQ. For the other side these states are equivalent to
 125  * the one it was in before.
 126  *
 127  * Packets are marked as ignored (sIG) if we don't know if they're valid
 128  * (for example a reincarnation of a connection we didn't notice is dead
 129  * already) and the server may send back a connection closing Reset or a
 130  * Response. They're also used for Sync/SyncAck packets, which we don't
 131  * care about.
 132  */
 133 static const u_int8_t
 134 dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = {
 135         [CT_DCCP_ROLE_CLIENT] = {
 136                 [DCCP_PKT_REQUEST] = {
 137                 /*
 138                  * sNO -> sRQ           Regular Request
 139                  * sRQ -> sRQ           Retransmitted Request or reincarnation
 140                  * sRS -> sRS           Retransmitted Request (apparently Response
 141                  *                      got lost after we saw it) or reincarnation
 142                  * sPO -> sIG           Ignore, conntrack might be out of sync
 143                  * sOP -> sIG           Ignore, conntrack might be out of sync
 144                  * sCR -> sIG           Ignore, conntrack might be out of sync
 145                  * sCG -> sIG           Ignore, conntrack might be out of sync
 146                  * sTW -> sRQ           Reincarnation
 147                  *
 148                  *      sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */
 149                         sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ,
 150                 },
 151                 [DCCP_PKT_RESPONSE] = {
 152                 /*
 153                  * sNO -> sIV           Invalid
 154                  * sRQ -> sIG           Ignore, might be response to ignored Request
 155                  * sRS -> sIG           Ignore, might be response to ignored Request
 156                  * sPO -> sIG           Ignore, might be response to ignored Request
 157                  * sOP -> sIG           Ignore, might be response to ignored Request
 158                  * sCR -> sIG           Ignore, might be response to ignored Request
 159                  * sCG -> sIG           Ignore, might be response to ignored Request
 160                  * sTW -> sIV           Invalid, reincarnation in reverse direction
 161                  *                      goes through sRQ
 162                  *
 163                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 164                         sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV,
 165                 },
 166                 [DCCP_PKT_ACK] = {
 167                 /*
 168                  * sNO -> sIV           No connection
 169                  * sRQ -> sIV           No connection
 170                  * sRS -> sPO           Ack for Response, move to PARTOPEN (8.1.5.)
 171                  * sPO -> sPO           Retransmitted Ack for Response, remain in PARTOPEN
 172                  * sOP -> sOP           Regular ACK, remain in OPEN
 173                  * sCR -> sCR           Ack in CLOSEREQ MAY be processed (8.3.)
 174                  * sCG -> sCG           Ack in CLOSING MAY be processed (8.3.)
 175                  * sTW -> sIV
 176                  *
 177                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 178                         sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
 179                 },
 180                 [DCCP_PKT_DATA] = {
 181                 /*
 182                  * sNO -> sIV           No connection
 183                  * sRQ -> sIV           No connection
 184                  * sRS -> sIV           No connection
 185                  * sPO -> sIV           MUST use DataAck in PARTOPEN state (8.1.5.)
 186                  * sOP -> sOP           Regular Data packet
 187                  * sCR -> sCR           Data in CLOSEREQ MAY be processed (8.3.)
 188                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 189                  * sTW -> sIV
 190                  *
 191                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 192                         sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV,
 193                 },
 194                 [DCCP_PKT_DATAACK] = {
 195                 /*
 196                  * sNO -> sIV           No connection
 197                  * sRQ -> sIV           No connection
 198                  * sRS -> sPO           Ack for Response, move to PARTOPEN (8.1.5.)
 199                  * sPO -> sPO           Remain in PARTOPEN state
 200                  * sOP -> sOP           Regular DataAck packet in OPEN state
 201                  * sCR -> sCR           DataAck in CLOSEREQ MAY be processed (8.3.)
 202                  * sCG -> sCG           DataAck in CLOSING MAY be processed (8.3.)
 203                  * sTW -> sIV
 204                  *
 205                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 206                         sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
 207                 },
 208                 [DCCP_PKT_CLOSEREQ] = {
 209                 /*
 210                  * CLOSEREQ may only be sent by the server.
 211                  *
 212                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 213                         sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV
 214                 },
 215                 [DCCP_PKT_CLOSE] = {
 216                 /*
 217                  * sNO -> sIV           No connection
 218                  * sRQ -> sIV           No connection
 219                  * sRS -> sIV           No connection
 220                  * sPO -> sCG           Client-initiated close
 221                  * sOP -> sCG           Client-initiated close
 222                  * sCR -> sCG           Close in response to CloseReq (8.3.)
 223                  * sCG -> sCG           Retransmit
 224                  * sTW -> sIV           Late retransmit, already in TIME_WAIT
 225                  *
 226                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 227                         sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV
 228                 },
 229                 [DCCP_PKT_RESET] = {
 230                 /*
 231                  * sNO -> sIV           No connection
 232                  * sRQ -> sTW           Sync received or timeout, SHOULD send Reset (8.1.1.)
 233                  * sRS -> sTW           Response received without Request
 234                  * sPO -> sTW           Timeout, SHOULD send Reset (8.1.5.)
 235                  * sOP -> sTW           Connection reset
 236                  * sCR -> sTW           Connection reset
 237                  * sCG -> sTW           Connection reset
 238                  * sTW -> sIG           Ignore (don't refresh timer)
 239                  *
 240                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 241                         sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG
 242                 },
 243                 [DCCP_PKT_SYNC] = {
 244                 /*
 245                  * We currently ignore Sync packets
 246                  *
 247                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 248                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 249                 },
 250                 [DCCP_PKT_SYNCACK] = {
 251                 /*
 252                  * We currently ignore SyncAck packets
 253                  *
 254                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 255                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 256                 },
 257         },
 258         [CT_DCCP_ROLE_SERVER] = {
 259                 [DCCP_PKT_REQUEST] = {
 260                 /*
 261                  * sNO -> sIV           Invalid
 262                  * sRQ -> sIG           Ignore, conntrack might be out of sync
 263                  * sRS -> sIG           Ignore, conntrack might be out of sync
 264                  * sPO -> sIG           Ignore, conntrack might be out of sync
 265                  * sOP -> sIG           Ignore, conntrack might be out of sync
 266                  * sCR -> sIG           Ignore, conntrack might be out of sync
 267                  * sCG -> sIG           Ignore, conntrack might be out of sync
 268                  * sTW -> sRQ           Reincarnation, must reverse roles
 269                  *
 270                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 271                         sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ
 272                 },
 273                 [DCCP_PKT_RESPONSE] = {
 274                 /*
 275                  * sNO -> sIV           Response without Request
 276                  * sRQ -> sRS           Response to clients Request
 277                  * sRS -> sRS           Retransmitted Response (8.1.3. SHOULD NOT)
 278                  * sPO -> sIG           Response to an ignored Request or late retransmit
 279                  * sOP -> sIG           Ignore, might be response to ignored Request
 280                  * sCR -> sIG           Ignore, might be response to ignored Request
 281                  * sCG -> sIG           Ignore, might be response to ignored Request
 282                  * sTW -> sIV           Invalid, Request from client in sTW moves to sRQ
 283                  *
 284                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 285                         sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV
 286                 },
 287                 [DCCP_PKT_ACK] = {
 288                 /*
 289                  * sNO -> sIV           No connection
 290                  * sRQ -> sIV           No connection
 291                  * sRS -> sIV           No connection
 292                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 293                  * sOP -> sOP           Regular Ack in OPEN state
 294                  * sCR -> sIV           Waiting for Close from client
 295                  * sCG -> sCG           Ack in CLOSING MAY be processed (8.3.)
 296                  * sTW -> sIV
 297                  *
 298                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 299                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 300                 },
 301                 [DCCP_PKT_DATA] = {
 302                 /*
 303                  * sNO -> sIV           No connection
 304                  * sRQ -> sIV           No connection
 305                  * sRS -> sIV           No connection
 306                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 307                  * sOP -> sOP           Regular Data packet in OPEN state
 308                  * sCR -> sIV           Waiting for Close from client
 309                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 310                  * sTW -> sIV
 311                  *
 312                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 313                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 314                 },
 315                 [DCCP_PKT_DATAACK] = {
 316                 /*
 317                  * sNO -> sIV           No connection
 318                  * sRQ -> sIV           No connection
 319                  * sRS -> sIV           No connection
 320                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 321                  * sOP -> sOP           Regular DataAck in OPEN state
 322                  * sCR -> sIV           Waiting for Close from client
 323                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 324                  * sTW -> sIV
 325                  *
 326                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 327                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 328                 },
 329                 [DCCP_PKT_CLOSEREQ] = {
 330                 /*
 331                  * sNO -> sIV           No connection
 332                  * sRQ -> sIV           No connection
 333                  * sRS -> sIV           No connection
 334                  * sPO -> sOP -> sCR    Move directly to CLOSEREQ (8.1.5.)
 335                  * sOP -> sCR           CloseReq in OPEN state
 336                  * sCR -> sCR           Retransmit
 337                  * sCG -> sCR           Simultaneous close, client sends another Close
 338                  * sTW -> sIV           Already closed
 339                  *
 340                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 341                         sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV
 342                 },
 343                 [DCCP_PKT_CLOSE] = {
 344                 /*
 345                  * sNO -> sIV           No connection
 346                  * sRQ -> sIV           No connection
 347                  * sRS -> sIV           No connection
 348                  * sPO -> sOP -> sCG    Move direcly to CLOSING
 349                  * sOP -> sCG           Move to CLOSING
 350                  * sCR -> sIV           Close after CloseReq is invalid
 351                  * sCG -> sCG           Retransmit
 352                  * sTW -> sIV           Already closed
 353                  *
 354                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 355                         sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV
 356                 },
 357                 [DCCP_PKT_RESET] = {
 358                 /*
 359                  * sNO -> sIV           No connection
 360                  * sRQ -> sTW           Reset in response to Request
 361                  * sRS -> sTW           Timeout, SHOULD send Reset (8.1.3.)
 362                  * sPO -> sTW           Timeout, SHOULD send Reset (8.1.3.)
 363                  * sOP -> sTW
 364                  * sCR -> sTW
 365                  * sCG -> sTW
 366                  * sTW -> sIG           Ignore (don't refresh timer)
 367                  *
 368                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */
 369                         sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG
 370                 },
 371                 [DCCP_PKT_SYNC] = {
 372                 /*
 373                  * We currently ignore Sync packets
 374                  *
 375                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 376                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 377                 },
 378                 [DCCP_PKT_SYNCACK] = {
 379                 /*
 380                  * We currently ignore SyncAck packets
 381                  *
 382                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 383                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 384                 },
 385         },
 386 };
 387
 388 /* this module per-net specifics */
 389 static int dccp_net_id;
 390 struct dccp_net {
 391         int dccp_loose;
 392         unsigned int dccp_timeout[CT_DCCP_MAX + 1];
 393 #ifdef CONFIG_SYSCTL
 394         struct ctl_table_header *sysctl_header;
 395         struct ctl_table *sysctl_table;
 396 #endif
 397 };
 398
 399 static inline struct dccp_net *dccp_pernet(struct net *net)
 400 {
 401         return net_generic(net, dccp_net_id);
 402 }
 403
 404 static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 405                               struct nf_conntrack_tuple *tuple)
 406 {
 407         struct dccp_hdr _hdr, *dh;
 408
 409         dh = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 410         if (dh == NULL)
 411                 return false;
 412
 413         tuple->src.u.dccp.port = dh->dccph_sport;
 414         tuple->dst.u.dccp.port = dh->dccph_dport;
 415         return true;
 416 }
 417
 418 static bool dccp_invert_tuple(struct nf_conntrack_tuple *inv,
 419                               const struct nf_conntrack_tuple *tuple)
 420 {
 421         inv->src.u.dccp.port = tuple->dst.u.dccp.port;
 422         inv->dst.u.dccp.port = tuple->src.u.dccp.port;
 423         return true;
 424 }
 425
 426 static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb,
 427                      unsigned int dataoff)
 428 {
 429         struct net *net = nf_ct_net(ct);
 430         struct dccp_net *dn;
 431         struct dccp_hdr _dh, *dh;
 432         const char *msg;
 433         u_int8_t state;
 434
 435         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 436         BUG_ON(dh == NULL);
 437
 438         state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE];
 439         switch (state) {
 440         default:
 441                 dn = dccp_pernet(net);
 442                 if (dn->dccp_loose == 0) {
 443                         msg = "nf_ct_dccp: not picking up existing connection ";
 444                         goto out_invalid;
 445                 }
 446         case CT_DCCP_REQUEST:
 447                 break;
 448         case CT_DCCP_INVALID:
 449                 msg = "nf_ct_dccp: invalid state transition ";
 450                 goto out_invalid;
 451         }
 452
 453         ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 454         ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 455         ct->proto.dccp.state = CT_DCCP_NONE;
 456         return true;
 457
 458 out_invalid:
 459         if (LOG_INVALID(net, IPPROTO_DCCP))
 460                 nf_log_packet(nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL, msg);
 461         return false;
 462 }
 463
 464 static u64 dccp_ack_seq(const struct dccp_hdr *dh)
 465 {
 466         const struct dccp_hdr_ack_bits *dhack;
 467
 468         dhack = (void *)dh + __dccp_basic_hdr_len(dh);
 469         return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
 470                      ntohl(dhack->dccph_ack_nr_low);
 471 }
 472
 473 static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
 474                        unsigned int dataoff, enum ip_conntrack_info ctinfo,
 475                        u_int8_t pf, unsigned int hooknum)
 476 {
 477         struct net *net = nf_ct_net(ct);
 478         struct dccp_net *dn;
 479         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 480         struct dccp_hdr _dh, *dh;
 481         u_int8_t type, old_state, new_state;
 482         enum ct_dccp_roles role;
 483
 484         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 485         BUG_ON(dh == NULL);
 486         type = dh->dccph_type;
 487
 488         if (type == DCCP_PKT_RESET &&
 489             !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 490                 /* Tear down connection immediately if only reply is a RESET */
 491                 nf_ct_kill_acct(ct, ctinfo, skb);
 492                 return NF_ACCEPT;
 493         }
 494
 495         write_lock_bh(&dccp_lock);
 496
 497         role = ct->proto.dccp.role[dir];
 498         old_state = ct->proto.dccp.state;
 499         new_state = dccp_state_table[role][type][old_state];
 500
 501         switch (new_state) {
 502         case CT_DCCP_REQUEST:
 503                 if (old_state == CT_DCCP_TIMEWAIT &&
 504                     role == CT_DCCP_ROLE_SERVER) {
 505                         /* Reincarnation in the reverse direction: reopen and
 506                          * reverse client/server roles. */
 507                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT;
 508                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER;
 509                 }
 510                 break;
 511         case CT_DCCP_RESPOND:
 512                 if (old_state == CT_DCCP_REQUEST)
 513                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 514                 break;
 515         case CT_DCCP_PARTOPEN:
 516                 if (old_state == CT_DCCP_RESPOND &&
 517                     type == DCCP_PKT_ACK &&
 518                     dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq)
 519                         set_bit(IPS_ASSURED_BIT, &ct->status);
 520                 break;
 521         case CT_DCCP_IGNORE:
 522                 /*
 523                  * Connection tracking might be out of sync, so we ignore
 524                  * packets that might establish a new connection and resync
 525                  * if the server responds with a valid Response.
 526                  */
 527                 if (ct->proto.dccp.last_dir == !dir &&
 528                     ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST &&
 529                     type == DCCP_PKT_RESPONSE) {
 530                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT;
 531                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER;
 532                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 533                         new_state = CT_DCCP_RESPOND;
 534                         break;
 535                 }
 536                 ct->proto.dccp.last_dir = dir;
 537                 ct->proto.dccp.last_pkt = type;
 538
 539                 write_unlock_bh(&dccp_lock);
 540                 if (LOG_INVALID(net, IPPROTO_DCCP))
 541                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 542                                       "nf_ct_dccp: invalid packet ignored ");
 543                 return NF_ACCEPT;
 544         case CT_DCCP_INVALID:
 545                 write_unlock_bh(&dccp_lock);
 546                 if (LOG_INVALID(net, IPPROTO_DCCP))
 547                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 548                                       "nf_ct_dccp: invalid state transition ");
 549                 return -NF_ACCEPT;
 550         }
 551
 552         ct->proto.dccp.last_dir = dir;
 553         ct->proto.dccp.last_pkt = type;
 554         ct->proto.dccp.state = new_state;
 555         write_unlock_bh(&dccp_lock);
 556
 557         if (new_state != old_state)
 558                 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 559
 560         dn = dccp_pernet(net);
 561         nf_ct_refresh_acct(ct, ctinfo, skb, dn->dccp_timeout[new_state]);
 562
 563         return NF_ACCEPT;
 564 }
 565
 566 static int dccp_error(struct net *net, struct sk_buff *skb,
 567                       unsigned int dataoff, enum ip_conntrack_info *ctinfo,
 568                       u_int8_t pf, unsigned int hooknum)
 569 {
 570         struct dccp_hdr _dh, *dh;
 571         unsigned int dccp_len = skb->len - dataoff;
 572         unsigned int cscov;
 573         const char *msg;
 574
 575         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
 576         if (dh == NULL) {
 577                 msg = "nf_ct_dccp: short packet ";
 578                 goto out_invalid;
 579         }
 580
 581         if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) ||
 582             dh->dccph_doff * 4 > dccp_len) {
 583                 msg = "nf_ct_dccp: truncated/malformed packet ";
 584                 goto out_invalid;
 585         }
 586
 587         cscov = dccp_len;
 588         if (dh->dccph_cscov) {
 589                 cscov = (dh->dccph_cscov - 1) * 4;
 590                 if (cscov > dccp_len) {
 591                         msg = "nf_ct_dccp: bad checksum coverage ";
 592                         goto out_invalid;
 593                 }
 594         }
 595
 596         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 597             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP,
 598                                 pf)) {
 599                 msg = "nf_ct_dccp: bad checksum ";
 600                 goto out_invalid;
 601         }
 602
 603         if (dh->dccph_type >= DCCP_PKT_INVALID) {
 604                 msg = "nf_ct_dccp: reserved packet type ";
 605                 goto out_invalid;
 606         }
 607
 608         return NF_ACCEPT;
 609
 610 out_invalid:
 611         if (LOG_INVALID(net, IPPROTO_DCCP))
 612                 nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg);
 613         return -NF_ACCEPT;
 614 }
 615
 616 static int dccp_print_tuple(struct seq_file *s,
 617                             const struct nf_conntrack_tuple *tuple)
 618 {
 619         return seq_printf(s, "sport=%hu dport=%hu ",
 620                           ntohs(tuple->src.u.dccp.port),
 621                           ntohs(tuple->dst.u.dccp.port));
 622 }
 623
 624 static int dccp_print_conntrack(struct seq_file *s, const struct nf_conn *ct)
 625 {
 626         return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
 627 }
 628
 629 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 630 static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 631                           const struct nf_conn *ct)
 632 {
 633         struct nlattr *nest_parms;
 634
 635         read_lock_bh(&dccp_lock);
 636         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
 637         if (!nest_parms)
 638                 goto nla_put_failure;
 639         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state);
 640         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_ROLE,
 641                    ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]);
 642         nla_nest_end(skb, nest_parms);
 643         read_unlock_bh(&dccp_lock);
 644         return 0;
 645
 646 nla_put_failure:
 647         read_unlock_bh(&dccp_lock);
 648         return -1;
 649 }
 650
 651 static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
 652         [CTA_PROTOINFO_DCCP_STATE]      = { .type = NLA_U8 },
 653         [CTA_PROTOINFO_DCCP_ROLE]       = { .type = NLA_U8 },
 654 };
 655
 656 static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
 657 {
 658         struct nlattr *attr = cda[CTA_PROTOINFO_DCCP];
 659         struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1];
 660         int err;
 661
 662         if (!attr)
 663                 return 0;
 664
 665         err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr,
 666                                dccp_nla_policy);
 667         if (err < 0)
 668                 return err;
 669
 670         if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
 671             !tb[CTA_PROTOINFO_DCCP_ROLE] ||
 672             nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX ||
 673             nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) {
 674                 return -EINVAL;
 675         }
 676
 677         write_lock_bh(&dccp_lock);
 678         ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
 679         if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) {
 680                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 681                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 682         } else {
 683                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
 684                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
 685         }
 686         write_unlock_bh(&dccp_lock);
 687         return 0;
 688 }
 689
 690 static int dccp_nlattr_size(void)
 691 {
 692         return nla_total_size(0)        /* CTA_PROTOINFO_DCCP */
 693                 + nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
 694 }
 695 #endif
 696
 697 #ifdef CONFIG_SYSCTL
 698 /* template, data assigned later */
 699 static struct ctl_table dccp_sysctl_table[] = {
 700         {
 701                 .ctl_name       = CTL_UNNUMBERED,
 702                 .procname       = "nf_conntrack_dccp_timeout_request",
 703                 .maxlen         = sizeof(unsigned int),
 704                 .mode           = 0644,
 705                 .proc_handler   = proc_dointvec_jiffies,
 706         },
 707         {
 708                 .ctl_name       = CTL_UNNUMBERED,
 709                 .procname       = "nf_conntrack_dccp_timeout_respond",
 710                 .maxlen         = sizeof(unsigned int),
 711                 .mode           = 0644,
 712                 .proc_handler   = proc_dointvec_jiffies,
 713         },
 714         {
 715                 .ctl_name       = CTL_UNNUMBERED,
 716                 .procname       = "nf_conntrack_dccp_timeout_partopen",
 717                 .maxlen         = sizeof(unsigned int),
 718                 .mode           = 0644,
 719                 .proc_handler   = proc_dointvec_jiffies,
 720         },
 721         {
 722                 .ctl_name       = CTL_UNNUMBERED,
 723                 .procname       = "nf_conntrack_dccp_timeout_open",
 724                 .maxlen         = sizeof(unsigned int),
 725                 .mode           = 0644,
 726                 .proc_handler   = proc_dointvec_jiffies,
 727         },
 728         {
 729                 .ctl_name       = CTL_UNNUMBERED,
 730                 .procname       = "nf_conntrack_dccp_timeout_closereq",
 731                 .maxlen         = sizeof(unsigned int),
 732                 .mode           = 0644,
 733                 .proc_handler   = proc_dointvec_jiffies,
 734         },
 735         {
 736                 .ctl_name       = CTL_UNNUMBERED,
 737                 .procname       = "nf_conntrack_dccp_timeout_closing",
 738                 .maxlen         = sizeof(unsigned int),
 739                 .mode           = 0644,
 740                 .proc_handler   = proc_dointvec_jiffies,
 741         },
 742         {
 743                 .ctl_name       = CTL_UNNUMBERED,
 744                 .procname       = "nf_conntrack_dccp_timeout_timewait",
 745                 .maxlen         = sizeof(unsigned int),
 746                 .mode           = 0644,
 747                 .proc_handler   = proc_dointvec_jiffies,
 748         },
 749         {
 750                 .ctl_name       = CTL_UNNUMBERED,
 751                 .procname       = "nf_conntrack_dccp_loose",
 752                 .maxlen         = sizeof(int),
 753                 .mode           = 0644,
 754                 .proc_handler   = proc_dointvec,
 755         },
 756         {
 757                 .ctl_name       = 0,
 758         }
 759 };
 760 #endif /* CONFIG_SYSCTL */
 761
 762 static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = {
 763         .l3proto                = AF_INET,
 764         .l4proto                = IPPROTO_DCCP,
 765         .name                   = "dccp",
 766         .pkt_to_tuple           = dccp_pkt_to_tuple,
 767         .invert_tuple           = dccp_invert_tuple,
 768         .new                    = dccp_new,
 769         .packet                 = dccp_packet,
 770         .error                  = dccp_error,
 771         .print_tuple            = dccp_print_tuple,
 772         .print_conntrack        = dccp_print_conntrack,
 773 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 774         .to_nlattr              = dccp_to_nlattr,
 775         .nlattr_size            = dccp_nlattr_size,
 776         .from_nlattr            = nlattr_to_dccp,
 777         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 778         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 779         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 780         .nla_policy             = nf_ct_port_nla_policy,
 781 #endif
 782 };
 783
 784 static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = {
 785         .l3proto                = AF_INET6,
 786         .l4proto                = IPPROTO_DCCP,
 787         .name                   = "dccp",
 788         .pkt_to_tuple           = dccp_pkt_to_tuple,
 789         .invert_tuple           = dccp_invert_tuple,
 790         .new                    = dccp_new,
 791         .packet                 = dccp_packet,
 792         .error                  = dccp_error,
 793         .print_tuple            = dccp_print_tuple,
 794         .print_conntrack        = dccp_print_conntrack,
 795 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 796         .to_nlattr              = dccp_to_nlattr,
 797         .nlattr_size            = dccp_nlattr_size,
 798         .from_nlattr            = nlattr_to_dccp,
 799         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 800         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 801         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 802         .nla_policy             = nf_ct_port_nla_policy,
 803 #endif
 804 };
 805
 806 static __net_init int dccp_net_init(struct net *net)
 807 {
 808         struct dccp_net *dn;
 809         int err;
 810
 811         dn = kmalloc(sizeof(*dn), GFP_KERNEL);
 812         if (!dn)
 813                 return -ENOMEM;
 814
 815         /* default values */
 816         dn->dccp_loose = 1;
 817         dn->dccp_timeout[CT_DCCP_REQUEST]       = 2 * DCCP_MSL;
 818         dn->dccp_timeout[CT_DCCP_RESPOND]       = 4 * DCCP_MSL;
 819         dn->dccp_timeout[CT_DCCP_PARTOPEN]      = 4 * DCCP_MSL;
 820         dn->dccp_timeout[CT_DCCP_OPEN]          = 12 * 3600 * HZ;
 821         dn->dccp_timeout[CT_DCCP_CLOSEREQ]      = 64 * HZ;
 822         dn->dccp_timeout[CT_DCCP_CLOSING]       = 64 * HZ;
 823         dn->dccp_timeout[CT_DCCP_TIMEWAIT]      = 2 * DCCP_MSL;
 824
 825         err = net_assign_generic(net, dccp_net_id, dn);
 826         if (err)
 827                 goto out;
 828
 829 #ifdef CONFIG_SYSCTL
 830         err = -ENOMEM;
 831         dn->sysctl_table = kmemdup(dccp_sysctl_table,
 832                         sizeof(dccp_sysctl_table), GFP_KERNEL);
 833         if (!dn->sysctl_table)
 834                 goto out;
 835
 836         dn->sysctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST];
 837         dn->sysctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND];
 838         dn->sysctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN];
 839         dn->sysctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN];
 840         dn->sysctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ];
 841         dn->sysctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
 842         dn->sysctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
 843         dn->sysctl_table[7].data = &dn->dccp_loose;
 844
 845         dn->sysctl_header = register_net_sysctl_table(net,
 846                         nf_net_netfilter_sysctl_path, dn->sysctl_table);
 847         if (!dn->sysctl_header) {
 848                 kfree(dn->sysctl_table);
 849                 goto out;
 850         }
 851 #endif
 852
 853         return 0;
 854
 855 out:
 856         kfree(dn);
 857         return err;
 858 }
 859
 860 static __net_exit void dccp_net_exit(struct net *net)
 861 {
 862         struct dccp_net *dn = dccp_pernet(net);
 863 #ifdef CONFIG_SYSCTL
 864         unregister_net_sysctl_table(dn->sysctl_header);
 865         kfree(dn->sysctl_table);
 866 #endif
 867         kfree(dn);
 868
 869         net_assign_generic(net, dccp_net_id, NULL);
 870 }
 871
 872 static struct pernet_operations dccp_net_ops = {
 873         .init = dccp_net_init,
 874         .exit = dccp_net_exit,
 875 };
 876
 877 static int __init nf_conntrack_proto_dccp_init(void)
 878 {
 879         int err;
 880
 881         err = register_pernet_gen_subsys(&dccp_net_id, &dccp_net_ops);
 882         if (err < 0)
 883                 goto err1;
 884
 885         err = nf_conntrack_l4proto_register(&dccp_proto4);
 886         if (err < 0)
 887                 goto err2;
 888
 889         err = nf_conntrack_l4proto_register(&dccp_proto6);
 890         if (err < 0)
 891                 goto err3;
 892         return 0;
 893
 894 err3:
 895         nf_conntrack_l4proto_unregister(&dccp_proto4);
 896 err2:
 897         unregister_pernet_gen_subsys(dccp_net_id, &dccp_net_ops);
 898 err1:
 899         return err;
 900 }
 901
 902 static void __exit nf_conntrack_proto_dccp_fini(void)
 903 {
 904         unregister_pernet_gen_subsys(dccp_net_id, &dccp_net_ops);
 905         nf_conntrack_l4proto_unregister(&dccp_proto6);
 906         nf_conntrack_l4proto_unregister(&dccp_proto4);
 907 }
 908
 909 module_init(nf_conntrack_proto_dccp_init);
 910 module_exit(nf_conntrack_proto_dccp_fini);
 911
 912 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 913 MODULE_DESCRIPTION("DCCP connection tracking protocol helper");
 914 MODULE_LICENSE("GPL");