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 #include <linux/slab.h>
  19
  20 #include <net/net_namespace.h>
  21 #include <net/netns/generic.h>
  22
  23 #include <linux/netfilter/nfnetlink_conntrack.h>
  24 #include <net/netfilter/nf_conntrack.h>
  25 #include <net/netfilter/nf_conntrack_l4proto.h>
  26 #include <net/netfilter/nf_conntrack_ecache.h>
  27 #include <net/netfilter/nf_log.h>
  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 transition 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 __read_mostly;
 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         ct->proto.dccp.last_pkt = DCCP_PKT_REQUEST;
 456         ct->proto.dccp.last_dir = IP_CT_DIR_ORIGINAL;
 457         ct->proto.dccp.handshake_seq = 0;
 458         return true;
 459
 460 out_invalid:
 461         if (LOG_INVALID(net, IPPROTO_DCCP))
 462                 nf_log_packet(nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL, msg);
 463         return false;
 464 }
 465
 466 static u64 dccp_ack_seq(const struct dccp_hdr *dh)
 467 {
 468         const struct dccp_hdr_ack_bits *dhack;
 469
 470         dhack = (void *)dh + __dccp_basic_hdr_len(dh);
 471         return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
 472                      ntohl(dhack->dccph_ack_nr_low);
 473 }
 474
 475 static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
 476                        unsigned int dataoff, enum ip_conntrack_info ctinfo,
 477                        u_int8_t pf, unsigned int hooknum)
 478 {
 479         struct net *net = nf_ct_net(ct);
 480         struct dccp_net *dn;
 481         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 482         struct dccp_hdr _dh, *dh;
 483         u_int8_t type, old_state, new_state;
 484         enum ct_dccp_roles role;
 485
 486         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh);
 487         BUG_ON(dh == NULL);
 488         type = dh->dccph_type;
 489
 490         if (type == DCCP_PKT_RESET &&
 491             !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 492                 /* Tear down connection immediately if only reply is a RESET */
 493                 nf_ct_kill_acct(ct, ctinfo, skb);
 494                 return NF_ACCEPT;
 495         }
 496
 497         spin_lock_bh(&ct->lock);
 498
 499         role = ct->proto.dccp.role[dir];
 500         old_state = ct->proto.dccp.state;
 501         new_state = dccp_state_table[role][type][old_state];
 502
 503         switch (new_state) {
 504         case CT_DCCP_REQUEST:
 505                 if (old_state == CT_DCCP_TIMEWAIT &&
 506                     role == CT_DCCP_ROLE_SERVER) {
 507                         /* Reincarnation in the reverse direction: reopen and
 508                          * reverse client/server roles. */
 509                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT;
 510                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER;
 511                 }
 512                 break;
 513         case CT_DCCP_RESPOND:
 514                 if (old_state == CT_DCCP_REQUEST)
 515                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 516                 break;
 517         case CT_DCCP_PARTOPEN:
 518                 if (old_state == CT_DCCP_RESPOND &&
 519                     type == DCCP_PKT_ACK &&
 520                     dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq)
 521                         set_bit(IPS_ASSURED_BIT, &ct->status);
 522                 break;
 523         case CT_DCCP_IGNORE:
 524                 /*
 525                  * Connection tracking might be out of sync, so we ignore
 526                  * packets that might establish a new connection and resync
 527                  * if the server responds with a valid Response.
 528                  */
 529                 if (ct->proto.dccp.last_dir == !dir &&
 530                     ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST &&
 531                     type == DCCP_PKT_RESPONSE) {
 532                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT;
 533                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER;
 534                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 535                         new_state = CT_DCCP_RESPOND;
 536                         break;
 537                 }
 538                 ct->proto.dccp.last_dir = dir;
 539                 ct->proto.dccp.last_pkt = type;
 540
 541                 spin_unlock_bh(&ct->lock);
 542                 if (LOG_INVALID(net, IPPROTO_DCCP))
 543                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 544                                       "nf_ct_dccp: invalid packet ignored ");
 545                 return NF_ACCEPT;
 546         case CT_DCCP_INVALID:
 547                 spin_unlock_bh(&ct->lock);
 548                 if (LOG_INVALID(net, IPPROTO_DCCP))
 549                         nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
 550                                       "nf_ct_dccp: invalid state transition ");
 551                 return -NF_ACCEPT;
 552         }
 553
 554         ct->proto.dccp.last_dir = dir;
 555         ct->proto.dccp.last_pkt = type;
 556         ct->proto.dccp.state = new_state;
 557         spin_unlock_bh(&ct->lock);
 558
 559         if (new_state != old_state)
 560                 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 561
 562         dn = dccp_pernet(net);
 563         nf_ct_refresh_acct(ct, ctinfo, skb, dn->dccp_timeout[new_state]);
 564
 565         return NF_ACCEPT;
 566 }
 567
 568 static int dccp_error(struct net *net, struct nf_conn *tmpl,
 569                       struct sk_buff *skb, unsigned int dataoff,
 570                       enum ip_conntrack_info *ctinfo,
 571                       u_int8_t pf, unsigned int hooknum)
 572 {
 573         struct dccp_hdr _dh, *dh;
 574         unsigned int dccp_len = skb->len - dataoff;
 575         unsigned int cscov;
 576         const char *msg;
 577
 578         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh);
 579         if (dh == NULL) {
 580                 msg = "nf_ct_dccp: short packet ";
 581                 goto out_invalid;
 582         }
 583
 584         if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) ||
 585             dh->dccph_doff * 4 > dccp_len) {
 586                 msg = "nf_ct_dccp: truncated/malformed packet ";
 587                 goto out_invalid;
 588         }
 589
 590         cscov = dccp_len;
 591         if (dh->dccph_cscov) {
 592                 cscov = (dh->dccph_cscov - 1) * 4;
 593                 if (cscov > dccp_len) {
 594                         msg = "nf_ct_dccp: bad checksum coverage ";
 595                         goto out_invalid;
 596                 }
 597         }
 598
 599         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 600             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP,
 601                                 pf)) {
 602                 msg = "nf_ct_dccp: bad checksum ";
 603                 goto out_invalid;
 604         }
 605
 606         if (dh->dccph_type >= DCCP_PKT_INVALID) {
 607                 msg = "nf_ct_dccp: reserved packet type ";
 608                 goto out_invalid;
 609         }
 610
 611         return NF_ACCEPT;
 612
 613 out_invalid:
 614         if (LOG_INVALID(net, IPPROTO_DCCP))
 615                 nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg);
 616         return -NF_ACCEPT;
 617 }
 618
 619 static int dccp_print_tuple(struct seq_file *s,
 620                             const struct nf_conntrack_tuple *tuple)
 621 {
 622         return seq_printf(s, "sport=%hu dport=%hu ",
 623                           ntohs(tuple->src.u.dccp.port),
 624                           ntohs(tuple->dst.u.dccp.port));
 625 }
 626
 627 static int dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 628 {
 629         return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
 630 }
 631
 632 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 633 static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 634                           struct nf_conn *ct)
 635 {
 636         struct nlattr *nest_parms;
 637
 638         spin_lock_bh(&ct->lock);
 639         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
 640         if (!nest_parms)
 641                 goto nla_put_failure;
 642         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state);
 643         NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_ROLE,
 644                    ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]);
 645         NLA_PUT_BE64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ,
 646                      cpu_to_be64(ct->proto.dccp.handshake_seq));
 647         nla_nest_end(skb, nest_parms);
 648         spin_unlock_bh(&ct->lock);
 649         return 0;
 650
 651 nla_put_failure:
 652         spin_unlock_bh(&ct->lock);
 653         return -1;
 654 }
 655
 656 static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
 657         [CTA_PROTOINFO_DCCP_STATE]      = { .type = NLA_U8 },
 658         [CTA_PROTOINFO_DCCP_ROLE]       = { .type = NLA_U8 },
 659         [CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 },
 660 };
 661
 662 static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
 663 {
 664         struct nlattr *attr = cda[CTA_PROTOINFO_DCCP];
 665         struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1];
 666         int err;
 667
 668         if (!attr)
 669                 return 0;
 670
 671         err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr,
 672                                dccp_nla_policy);
 673         if (err < 0)
 674                 return err;
 675
 676         if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
 677             !tb[CTA_PROTOINFO_DCCP_ROLE] ||
 678             nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX ||
 679             nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) {
 680                 return -EINVAL;
 681         }
 682
 683         spin_lock_bh(&ct->lock);
 684         ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
 685         if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) {
 686                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 687                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 688         } else {
 689                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
 690                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
 691         }
 692         if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) {
 693                 ct->proto.dccp.handshake_seq =
 694                 be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]));
 695         }
 696         spin_unlock_bh(&ct->lock);
 697         return 0;
 698 }
 699
 700 static int dccp_nlattr_size(void)
 701 {
 702         return nla_total_size(0)        /* CTA_PROTOINFO_DCCP */
 703                 + nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
 704 }
 705 #endif
 706
 707 #ifdef CONFIG_SYSCTL
 708 /* template, data assigned later */
 709 static struct ctl_table dccp_sysctl_table[] = {
 710         {
 711                 .procname       = "nf_conntrack_dccp_timeout_request",
 712                 .maxlen         = sizeof(unsigned int),
 713                 .mode           = 0644,
 714                 .proc_handler   = proc_dointvec_jiffies,
 715         },
 716         {
 717                 .procname       = "nf_conntrack_dccp_timeout_respond",
 718                 .maxlen         = sizeof(unsigned int),
 719                 .mode           = 0644,
 720                 .proc_handler   = proc_dointvec_jiffies,
 721         },
 722         {
 723                 .procname       = "nf_conntrack_dccp_timeout_partopen",
 724                 .maxlen         = sizeof(unsigned int),
 725                 .mode           = 0644,
 726                 .proc_handler   = proc_dointvec_jiffies,
 727         },
 728         {
 729                 .procname       = "nf_conntrack_dccp_timeout_open",
 730                 .maxlen         = sizeof(unsigned int),
 731                 .mode           = 0644,
 732                 .proc_handler   = proc_dointvec_jiffies,
 733         },
 734         {
 735                 .procname       = "nf_conntrack_dccp_timeout_closereq",
 736                 .maxlen         = sizeof(unsigned int),
 737                 .mode           = 0644,
 738                 .proc_handler   = proc_dointvec_jiffies,
 739         },
 740         {
 741                 .procname       = "nf_conntrack_dccp_timeout_closing",
 742                 .maxlen         = sizeof(unsigned int),
 743                 .mode           = 0644,
 744                 .proc_handler   = proc_dointvec_jiffies,
 745         },
 746         {
 747                 .procname       = "nf_conntrack_dccp_timeout_timewait",
 748                 .maxlen         = sizeof(unsigned int),
 749                 .mode           = 0644,
 750                 .proc_handler   = proc_dointvec_jiffies,
 751         },
 752         {
 753                 .procname       = "nf_conntrack_dccp_loose",
 754                 .maxlen         = sizeof(int),
 755                 .mode           = 0644,
 756                 .proc_handler   = proc_dointvec,
 757         },
 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 = dccp_pernet(net);
 809
 810         /* default values */
 811         dn->dccp_loose = 1;
 812         dn->dccp_timeout[CT_DCCP_REQUEST]       = 2 * DCCP_MSL;
 813         dn->dccp_timeout[CT_DCCP_RESPOND]       = 4 * DCCP_MSL;
 814         dn->dccp_timeout[CT_DCCP_PARTOPEN]      = 4 * DCCP_MSL;
 815         dn->dccp_timeout[CT_DCCP_OPEN]          = 12 * 3600 * HZ;
 816         dn->dccp_timeout[CT_DCCP_CLOSEREQ]      = 64 * HZ;
 817         dn->dccp_timeout[CT_DCCP_CLOSING]       = 64 * HZ;
 818         dn->dccp_timeout[CT_DCCP_TIMEWAIT]      = 2 * DCCP_MSL;
 819
 820 #ifdef CONFIG_SYSCTL
 821         dn->sysctl_table = kmemdup(dccp_sysctl_table,
 822                         sizeof(dccp_sysctl_table), GFP_KERNEL);
 823         if (!dn->sysctl_table)
 824                 return -ENOMEM;
 825
 826         dn->sysctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST];
 827         dn->sysctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND];
 828         dn->sysctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN];
 829         dn->sysctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN];
 830         dn->sysctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ];
 831         dn->sysctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
 832         dn->sysctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
 833         dn->sysctl_table[7].data = &dn->dccp_loose;
 834
 835         dn->sysctl_header = register_net_sysctl_table(net,
 836                         nf_net_netfilter_sysctl_path, dn->sysctl_table);
 837         if (!dn->sysctl_header) {
 838                 kfree(dn->sysctl_table);
 839                 return -ENOMEM;
 840         }
 841 #endif
 842
 843         return 0;
 844 }
 845
 846 static __net_exit void dccp_net_exit(struct net *net)
 847 {
 848         struct dccp_net *dn = dccp_pernet(net);
 849 #ifdef CONFIG_SYSCTL
 850         unregister_net_sysctl_table(dn->sysctl_header);
 851         kfree(dn->sysctl_table);
 852 #endif
 853 }
 854
 855 static struct pernet_operations dccp_net_ops = {
 856         .init = dccp_net_init,
 857         .exit = dccp_net_exit,
 858         .id   = &dccp_net_id,
 859         .size = sizeof(struct dccp_net),
 860 };
 861
 862 static int __init nf_conntrack_proto_dccp_init(void)
 863 {
 864         int err;
 865
 866         err = register_pernet_subsys(&dccp_net_ops);
 867         if (err < 0)
 868                 goto err1;
 869
 870         err = nf_conntrack_l4proto_register(&dccp_proto4);
 871         if (err < 0)
 872                 goto err2;
 873
 874         err = nf_conntrack_l4proto_register(&dccp_proto6);
 875         if (err < 0)
 876                 goto err3;
 877         return 0;
 878
 879 err3:
 880         nf_conntrack_l4proto_unregister(&dccp_proto4);
 881 err2:
 882         unregister_pernet_subsys(&dccp_net_ops);
 883 err1:
 884         return err;
 885 }
 886
 887 static void __exit nf_conntrack_proto_dccp_fini(void)
 888 {
 889         unregister_pernet_subsys(&dccp_net_ops);
 890         nf_conntrack_l4proto_unregister(&dccp_proto6);
 891         nf_conntrack_l4proto_unregister(&dccp_proto4);
 892 }
 893
 894 module_init(nf_conntrack_proto_dccp_init);
 895 module_exit(nf_conntrack_proto_dccp_fini);
 896
 897 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 898 MODULE_DESCRIPTION("DCCP connection tracking protocol helper");
 899 MODULE_LICENSE("GPL");