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/init.h>
  13 #include <linux/sysctl.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/dccp.h>
  17 #include <linux/slab.h>
  18
  19 #include <net/net_namespace.h>
  20 #include <net/netns/generic.h>
  21
  22 #include <linux/netfilter/nfnetlink_conntrack.h>
  23 #include <net/netfilter/nf_conntrack.h>
  24 #include <net/netfilter/nf_conntrack_l4proto.h>
  25 #include <net/netfilter/nf_conntrack_ecache.h>
  26 #include <net/netfilter/nf_log.h>
  27
  28 /* Timeouts are based on values from RFC4340:
  29  *
  30  * - REQUEST:
  31  *
  32  *   8.1.2. Client Request
  33  *
  34  *   A client MAY give up on its DCCP-Requests after some time
  35  *   (3 minutes, for example).
  36  *
  37  * - RESPOND:
  38  *
  39  *   8.1.3. Server Response
  40  *
  41  *   It MAY also leave the RESPOND state for CLOSED after a timeout of
  42  *   not less than 4MSL (8 minutes);
  43  *
  44  * - PARTOPEN:
  45  *
  46  *   8.1.5. Handshake Completion
  47  *
  48  *   If the client remains in PARTOPEN for more than 4MSL (8 minutes),
  49  *   it SHOULD reset the connection with Reset Code 2, "Aborted".
  50  *
  51  * - OPEN:
  52  *
  53  *   The DCCP timestamp overflows after 11.9 hours. If the connection
  54  *   stays idle this long the sequence number won't be recognized
  55  *   as valid anymore.
  56  *
  57  * - CLOSEREQ/CLOSING:
  58  *
  59  *   8.3. Termination
  60  *
  61  *   The retransmission timer should initially be set to go off in two
  62  *   round-trip times and should back off to not less than once every
  63  *   64 seconds ...
  64  *
  65  * - TIMEWAIT:
  66  *
  67  *   4.3. States
  68  *
  69  *   A server or client socket remains in this state for 2MSL (4 minutes)
  70  *   after the connection has been town down, ...
  71  */
  72
  73 #define DCCP_MSL (2 * 60 * HZ)
  74
  75 static const char * const dccp_state_names[] = {
  76         [CT_DCCP_NONE]          = "NONE",
  77         [CT_DCCP_REQUEST]       = "REQUEST",
  78         [CT_DCCP_RESPOND]       = "RESPOND",
  79         [CT_DCCP_PARTOPEN]      = "PARTOPEN",
  80         [CT_DCCP_OPEN]          = "OPEN",
  81         [CT_DCCP_CLOSEREQ]      = "CLOSEREQ",
  82         [CT_DCCP_CLOSING]       = "CLOSING",
  83         [CT_DCCP_TIMEWAIT]      = "TIMEWAIT",
  84         [CT_DCCP_IGNORE]        = "IGNORE",
  85         [CT_DCCP_INVALID]       = "INVALID",
  86 };
  87
  88 #define sNO     CT_DCCP_NONE
  89 #define sRQ     CT_DCCP_REQUEST
  90 #define sRS     CT_DCCP_RESPOND
  91 #define sPO     CT_DCCP_PARTOPEN
  92 #define sOP     CT_DCCP_OPEN
  93 #define sCR     CT_DCCP_CLOSEREQ
  94 #define sCG     CT_DCCP_CLOSING
  95 #define sTW     CT_DCCP_TIMEWAIT
  96 #define sIG     CT_DCCP_IGNORE
  97 #define sIV     CT_DCCP_INVALID
  98
  99 /*
 100  * DCCP state transition table
 101  *
 102  * The assumption is the same as for TCP tracking:
 103  *
 104  * We are the man in the middle. All the packets go through us but might
 105  * get lost in transit to the destination. It is assumed that the destination
 106  * can't receive segments we haven't seen.
 107  *
 108  * The following states exist:
 109  *
 110  * NONE:        Initial state, expecting Request
 111  * REQUEST:     Request seen, waiting for Response from server
 112  * RESPOND:     Response from server seen, waiting for Ack from client
 113  * PARTOPEN:    Ack after Response seen, waiting for packet other than Response,
 114  *              Reset or Sync from server
 115  * OPEN:        Packet other than Response, Reset or Sync seen
 116  * CLOSEREQ:    CloseReq from server seen, expecting Close from client
 117  * CLOSING:     Close seen, expecting Reset
 118  * TIMEWAIT:    Reset seen
 119  * IGNORE:      Not determinable whether packet is valid
 120  *
 121  * Some states exist only on one side of the connection: REQUEST, RESPOND,
 122  * PARTOPEN, CLOSEREQ. For the other side these states are equivalent to
 123  * the one it was in before.
 124  *
 125  * Packets are marked as ignored (sIG) if we don't know if they're valid
 126  * (for example a reincarnation of a connection we didn't notice is dead
 127  * already) and the server may send back a connection closing Reset or a
 128  * Response. They're also used for Sync/SyncAck packets, which we don't
 129  * care about.
 130  */
 131 static const u_int8_t
 132 dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = {
 133         [CT_DCCP_ROLE_CLIENT] = {
 134                 [DCCP_PKT_REQUEST] = {
 135                 /*
 136                  * sNO -> sRQ           Regular Request
 137                  * sRQ -> sRQ           Retransmitted Request or reincarnation
 138                  * sRS -> sRS           Retransmitted Request (apparently Response
 139                  *                      got lost after we saw it) or reincarnation
 140                  * sPO -> sIG           Ignore, conntrack might be out of sync
 141                  * sOP -> sIG           Ignore, conntrack might be out of sync
 142                  * sCR -> sIG           Ignore, conntrack might be out of sync
 143                  * sCG -> sIG           Ignore, conntrack might be out of sync
 144                  * sTW -> sRQ           Reincarnation
 145                  *
 146                  *      sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */
 147                         sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ,
 148                 },
 149                 [DCCP_PKT_RESPONSE] = {
 150                 /*
 151                  * sNO -> sIV           Invalid
 152                  * sRQ -> sIG           Ignore, might be response to ignored Request
 153                  * sRS -> sIG           Ignore, might be response to ignored Request
 154                  * sPO -> sIG           Ignore, might be response to ignored Request
 155                  * sOP -> sIG           Ignore, might be response to ignored Request
 156                  * sCR -> sIG           Ignore, might be response to ignored Request
 157                  * sCG -> sIG           Ignore, might be response to ignored Request
 158                  * sTW -> sIV           Invalid, reincarnation in reverse direction
 159                  *                      goes through sRQ
 160                  *
 161                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 162                         sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV,
 163                 },
 164                 [DCCP_PKT_ACK] = {
 165                 /*
 166                  * sNO -> sIV           No connection
 167                  * sRQ -> sIV           No connection
 168                  * sRS -> sPO           Ack for Response, move to PARTOPEN (8.1.5.)
 169                  * sPO -> sPO           Retransmitted Ack for Response, remain in PARTOPEN
 170                  * sOP -> sOP           Regular ACK, remain in OPEN
 171                  * sCR -> sCR           Ack in CLOSEREQ MAY be processed (8.3.)
 172                  * sCG -> sCG           Ack in CLOSING MAY be processed (8.3.)
 173                  * sTW -> sIV
 174                  *
 175                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 176                         sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
 177                 },
 178                 [DCCP_PKT_DATA] = {
 179                 /*
 180                  * sNO -> sIV           No connection
 181                  * sRQ -> sIV           No connection
 182                  * sRS -> sIV           No connection
 183                  * sPO -> sIV           MUST use DataAck in PARTOPEN state (8.1.5.)
 184                  * sOP -> sOP           Regular Data packet
 185                  * sCR -> sCR           Data in CLOSEREQ MAY be processed (8.3.)
 186                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 187                  * sTW -> sIV
 188                  *
 189                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 190                         sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV,
 191                 },
 192                 [DCCP_PKT_DATAACK] = {
 193                 /*
 194                  * sNO -> sIV           No connection
 195                  * sRQ -> sIV           No connection
 196                  * sRS -> sPO           Ack for Response, move to PARTOPEN (8.1.5.)
 197                  * sPO -> sPO           Remain in PARTOPEN state
 198                  * sOP -> sOP           Regular DataAck packet in OPEN state
 199                  * sCR -> sCR           DataAck in CLOSEREQ MAY be processed (8.3.)
 200                  * sCG -> sCG           DataAck in CLOSING MAY be processed (8.3.)
 201                  * sTW -> sIV
 202                  *
 203                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 204                         sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
 205                 },
 206                 [DCCP_PKT_CLOSEREQ] = {
 207                 /*
 208                  * CLOSEREQ may only be sent by the server.
 209                  *
 210                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 211                         sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV
 212                 },
 213                 [DCCP_PKT_CLOSE] = {
 214                 /*
 215                  * sNO -> sIV           No connection
 216                  * sRQ -> sIV           No connection
 217                  * sRS -> sIV           No connection
 218                  * sPO -> sCG           Client-initiated close
 219                  * sOP -> sCG           Client-initiated close
 220                  * sCR -> sCG           Close in response to CloseReq (8.3.)
 221                  * sCG -> sCG           Retransmit
 222                  * sTW -> sIV           Late retransmit, already in TIME_WAIT
 223                  *
 224                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 225                         sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV
 226                 },
 227                 [DCCP_PKT_RESET] = {
 228                 /*
 229                  * sNO -> sIV           No connection
 230                  * sRQ -> sTW           Sync received or timeout, SHOULD send Reset (8.1.1.)
 231                  * sRS -> sTW           Response received without Request
 232                  * sPO -> sTW           Timeout, SHOULD send Reset (8.1.5.)
 233                  * sOP -> sTW           Connection reset
 234                  * sCR -> sTW           Connection reset
 235                  * sCG -> sTW           Connection reset
 236                  * sTW -> sIG           Ignore (don't refresh timer)
 237                  *
 238                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 239                         sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG
 240                 },
 241                 [DCCP_PKT_SYNC] = {
 242                 /*
 243                  * We currently ignore Sync packets
 244                  *
 245                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 246                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 247                 },
 248                 [DCCP_PKT_SYNCACK] = {
 249                 /*
 250                  * We currently ignore SyncAck packets
 251                  *
 252                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 253                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 254                 },
 255         },
 256         [CT_DCCP_ROLE_SERVER] = {
 257                 [DCCP_PKT_REQUEST] = {
 258                 /*
 259                  * sNO -> sIV           Invalid
 260                  * sRQ -> sIG           Ignore, conntrack might be out of sync
 261                  * sRS -> sIG           Ignore, conntrack might be out of sync
 262                  * sPO -> sIG           Ignore, conntrack might be out of sync
 263                  * sOP -> sIG           Ignore, conntrack might be out of sync
 264                  * sCR -> sIG           Ignore, conntrack might be out of sync
 265                  * sCG -> sIG           Ignore, conntrack might be out of sync
 266                  * sTW -> sRQ           Reincarnation, must reverse roles
 267                  *
 268                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 269                         sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ
 270                 },
 271                 [DCCP_PKT_RESPONSE] = {
 272                 /*
 273                  * sNO -> sIV           Response without Request
 274                  * sRQ -> sRS           Response to clients Request
 275                  * sRS -> sRS           Retransmitted Response (8.1.3. SHOULD NOT)
 276                  * sPO -> sIG           Response to an ignored Request or late retransmit
 277                  * sOP -> sIG           Ignore, might be response to ignored Request
 278                  * sCR -> sIG           Ignore, might be response to ignored Request
 279                  * sCG -> sIG           Ignore, might be response to ignored Request
 280                  * sTW -> sIV           Invalid, Request from client in sTW moves to sRQ
 281                  *
 282                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 283                         sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV
 284                 },
 285                 [DCCP_PKT_ACK] = {
 286                 /*
 287                  * sNO -> sIV           No connection
 288                  * sRQ -> sIV           No connection
 289                  * sRS -> sIV           No connection
 290                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 291                  * sOP -> sOP           Regular Ack in OPEN state
 292                  * sCR -> sIV           Waiting for Close from client
 293                  * sCG -> sCG           Ack in CLOSING MAY be processed (8.3.)
 294                  * sTW -> sIV
 295                  *
 296                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 297                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 298                 },
 299                 [DCCP_PKT_DATA] = {
 300                 /*
 301                  * sNO -> sIV           No connection
 302                  * sRQ -> sIV           No connection
 303                  * sRS -> sIV           No connection
 304                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 305                  * sOP -> sOP           Regular Data packet in OPEN state
 306                  * sCR -> sIV           Waiting for Close from client
 307                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 308                  * sTW -> sIV
 309                  *
 310                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 311                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 312                 },
 313                 [DCCP_PKT_DATAACK] = {
 314                 /*
 315                  * sNO -> sIV           No connection
 316                  * sRQ -> sIV           No connection
 317                  * sRS -> sIV           No connection
 318                  * sPO -> sOP           Enter OPEN state (8.1.5.)
 319                  * sOP -> sOP           Regular DataAck in OPEN state
 320                  * sCR -> sIV           Waiting for Close from client
 321                  * sCG -> sCG           Data in CLOSING MAY be processed (8.3.)
 322                  * sTW -> sIV
 323                  *
 324                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 325                         sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
 326                 },
 327                 [DCCP_PKT_CLOSEREQ] = {
 328                 /*
 329                  * sNO -> sIV           No connection
 330                  * sRQ -> sIV           No connection
 331                  * sRS -> sIV           No connection
 332                  * sPO -> sOP -> sCR    Move directly to CLOSEREQ (8.1.5.)
 333                  * sOP -> sCR           CloseReq in OPEN state
 334                  * sCR -> sCR           Retransmit
 335                  * sCG -> sCR           Simultaneous close, client sends another Close
 336                  * sTW -> sIV           Already closed
 337                  *
 338                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 339                         sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV
 340                 },
 341                 [DCCP_PKT_CLOSE] = {
 342                 /*
 343                  * sNO -> sIV           No connection
 344                  * sRQ -> sIV           No connection
 345                  * sRS -> sIV           No connection
 346                  * sPO -> sOP -> sCG    Move direcly to CLOSING
 347                  * sOP -> sCG           Move to CLOSING
 348                  * sCR -> sIV           Close after CloseReq is invalid
 349                  * sCG -> sCG           Retransmit
 350                  * sTW -> sIV           Already closed
 351                  *
 352                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 353                         sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV
 354                 },
 355                 [DCCP_PKT_RESET] = {
 356                 /*
 357                  * sNO -> sIV           No connection
 358                  * sRQ -> sTW           Reset in response to Request
 359                  * sRS -> sTW           Timeout, SHOULD send Reset (8.1.3.)
 360                  * sPO -> sTW           Timeout, SHOULD send Reset (8.1.3.)
 361                  * sOP -> sTW
 362                  * sCR -> sTW
 363                  * sCG -> sTW
 364                  * sTW -> sIG           Ignore (don't refresh timer)
 365                  *
 366                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */
 367                         sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG
 368                 },
 369                 [DCCP_PKT_SYNC] = {
 370                 /*
 371                  * We currently ignore Sync packets
 372                  *
 373                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 374                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 375                 },
 376                 [DCCP_PKT_SYNCACK] = {
 377                 /*
 378                  * We currently ignore SyncAck packets
 379                  *
 380                  *      sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
 381                         sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 382                 },
 383         },
 384 };
 385
 386 static inline struct nf_dccp_net *dccp_pernet(struct net *net)
 387 {
 388         return &net->ct.nf_ct_proto.dccp;
 389 }
 390
 391 static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
 392                               struct net *net, struct nf_conntrack_tuple *tuple)
 393 {
 394         struct dccp_hdr _hdr, *dh;
 395
 396         /* Actually only need first 4 bytes to get ports. */
 397         dh = skb_header_pointer(skb, dataoff, 4, &_hdr);
 398         if (dh == NULL)
 399                 return false;
 400
 401         tuple->src.u.dccp.port = dh->dccph_sport;
 402         tuple->dst.u.dccp.port = dh->dccph_dport;
 403         return true;
 404 }
 405
 406 static bool dccp_invert_tuple(struct nf_conntrack_tuple *inv,
 407                               const struct nf_conntrack_tuple *tuple)
 408 {
 409         inv->src.u.dccp.port = tuple->dst.u.dccp.port;
 410         inv->dst.u.dccp.port = tuple->src.u.dccp.port;
 411         return true;
 412 }
 413
 414 static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb,
 415                      unsigned int dataoff, unsigned int *timeouts)
 416 {
 417         struct net *net = nf_ct_net(ct);
 418         struct nf_dccp_net *dn;
 419         struct dccp_hdr _dh, *dh;
 420         const char *msg;
 421         u_int8_t state;
 422
 423         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh);
 424         BUG_ON(dh == NULL);
 425
 426         state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE];
 427         switch (state) {
 428         default:
 429                 dn = dccp_pernet(net);
 430                 if (dn->dccp_loose == 0) {
 431                         msg = "nf_ct_dccp: not picking up existing connection ";
 432                         goto out_invalid;
 433                 }
 434         case CT_DCCP_REQUEST:
 435                 break;
 436         case CT_DCCP_INVALID:
 437                 msg = "nf_ct_dccp: invalid state transition ";
 438                 goto out_invalid;
 439         }
 440
 441         ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 442         ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 443         ct->proto.dccp.state = CT_DCCP_NONE;
 444         ct->proto.dccp.last_pkt = DCCP_PKT_REQUEST;
 445         ct->proto.dccp.last_dir = IP_CT_DIR_ORIGINAL;
 446         ct->proto.dccp.handshake_seq = 0;
 447         return true;
 448
 449 out_invalid:
 450         if (LOG_INVALID(net, IPPROTO_DCCP))
 451                 nf_log_packet(net, nf_ct_l3num(ct), 0, skb, NULL, NULL,
 452                               NULL, "%s", msg);
 453         return false;
 454 }
 455
 456 static u64 dccp_ack_seq(const struct dccp_hdr *dh)
 457 {
 458         const struct dccp_hdr_ack_bits *dhack;
 459
 460         dhack = (void *)dh + __dccp_basic_hdr_len(dh);
 461         return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
 462                      ntohl(dhack->dccph_ack_nr_low);
 463 }
 464
 465 static unsigned int *dccp_get_timeouts(struct net *net)
 466 {
 467         return dccp_pernet(net)->dccp_timeout;
 468 }
 469
 470 static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
 471                        unsigned int dataoff, enum ip_conntrack_info ctinfo,
 472                        u_int8_t pf, unsigned int hooknum,
 473                        unsigned int *timeouts)
 474 {
 475         struct net *net = nf_ct_net(ct);
 476         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 477         struct dccp_hdr _dh, *dh;
 478         u_int8_t type, old_state, new_state;
 479         enum ct_dccp_roles role;
 480
 481         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh);
 482         BUG_ON(dh == NULL);
 483         type = dh->dccph_type;
 484
 485         if (type == DCCP_PKT_RESET &&
 486             !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 487                 /* Tear down connection immediately if only reply is a RESET */
 488                 nf_ct_kill_acct(ct, ctinfo, skb);
 489                 return NF_ACCEPT;
 490         }
 491
 492         spin_lock_bh(&ct->lock);
 493
 494         role = ct->proto.dccp.role[dir];
 495         old_state = ct->proto.dccp.state;
 496         new_state = dccp_state_table[role][type][old_state];
 497
 498         switch (new_state) {
 499         case CT_DCCP_REQUEST:
 500                 if (old_state == CT_DCCP_TIMEWAIT &&
 501                     role == CT_DCCP_ROLE_SERVER) {
 502                         /* Reincarnation in the reverse direction: reopen and
 503                          * reverse client/server roles. */
 504                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT;
 505                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER;
 506                 }
 507                 break;
 508         case CT_DCCP_RESPOND:
 509                 if (old_state == CT_DCCP_REQUEST)
 510                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 511                 break;
 512         case CT_DCCP_PARTOPEN:
 513                 if (old_state == CT_DCCP_RESPOND &&
 514                     type == DCCP_PKT_ACK &&
 515                     dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq)
 516                         set_bit(IPS_ASSURED_BIT, &ct->status);
 517                 break;
 518         case CT_DCCP_IGNORE:
 519                 /*
 520                  * Connection tracking might be out of sync, so we ignore
 521                  * packets that might establish a new connection and resync
 522                  * if the server responds with a valid Response.
 523                  */
 524                 if (ct->proto.dccp.last_dir == !dir &&
 525                     ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST &&
 526                     type == DCCP_PKT_RESPONSE) {
 527                         ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT;
 528                         ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER;
 529                         ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
 530                         new_state = CT_DCCP_RESPOND;
 531                         break;
 532                 }
 533                 ct->proto.dccp.last_dir = dir;
 534                 ct->proto.dccp.last_pkt = type;
 535
 536                 spin_unlock_bh(&ct->lock);
 537                 if (LOG_INVALID(net, IPPROTO_DCCP))
 538                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 539                                       "nf_ct_dccp: invalid packet ignored ");
 540                 return NF_ACCEPT;
 541         case CT_DCCP_INVALID:
 542                 spin_unlock_bh(&ct->lock);
 543                 if (LOG_INVALID(net, IPPROTO_DCCP))
 544                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 545                                       "nf_ct_dccp: invalid state transition ");
 546                 return -NF_ACCEPT;
 547         }
 548
 549         ct->proto.dccp.last_dir = dir;
 550         ct->proto.dccp.last_pkt = type;
 551         ct->proto.dccp.state = new_state;
 552         spin_unlock_bh(&ct->lock);
 553
 554         if (new_state != old_state)
 555                 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
 556
 557         nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
 558
 559         return NF_ACCEPT;
 560 }
 561
 562 static int dccp_error(struct net *net, struct nf_conn *tmpl,
 563                       struct sk_buff *skb, unsigned int dataoff,
 564                       enum ip_conntrack_info *ctinfo,
 565                       u_int8_t pf, unsigned int hooknum)
 566 {
 567         struct dccp_hdr _dh, *dh;
 568         unsigned int dccp_len = skb->len - dataoff;
 569         unsigned int cscov;
 570         const char *msg;
 571
 572         dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh);
 573         if (dh == NULL) {
 574                 msg = "nf_ct_dccp: short packet ";
 575                 goto out_invalid;
 576         }
 577
 578         if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) ||
 579             dh->dccph_doff * 4 > dccp_len) {
 580                 msg = "nf_ct_dccp: truncated/malformed packet ";
 581                 goto out_invalid;
 582         }
 583
 584         cscov = dccp_len;
 585         if (dh->dccph_cscov) {
 586                 cscov = (dh->dccph_cscov - 1) * 4;
 587                 if (cscov > dccp_len) {
 588                         msg = "nf_ct_dccp: bad checksum coverage ";
 589                         goto out_invalid;
 590                 }
 591         }
 592
 593         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 594             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP,
 595                                 pf)) {
 596                 msg = "nf_ct_dccp: bad checksum ";
 597                 goto out_invalid;
 598         }
 599
 600         if (dh->dccph_type >= DCCP_PKT_INVALID) {
 601                 msg = "nf_ct_dccp: reserved packet type ";
 602                 goto out_invalid;
 603         }
 604
 605         return NF_ACCEPT;
 606
 607 out_invalid:
 608         if (LOG_INVALID(net, IPPROTO_DCCP))
 609                 nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL, "%s", msg);
 610         return -NF_ACCEPT;
 611 }
 612
 613 static void dccp_print_tuple(struct seq_file *s,
 614                              const struct nf_conntrack_tuple *tuple)
 615 {
 616         seq_printf(s, "sport=%hu dport=%hu ",
 617                    ntohs(tuple->src.u.dccp.port),
 618                    ntohs(tuple->dst.u.dccp.port));
 619 }
 620
 621 static void dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 622 {
 623         seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
 624 }
 625
 626 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 627 static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 628                           struct nf_conn *ct)
 629 {
 630         struct nlattr *nest_parms;
 631
 632         spin_lock_bh(&ct->lock);
 633         nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
 634         if (!nest_parms)
 635                 goto nla_put_failure;
 636         if (nla_put_u8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state) ||
 637             nla_put_u8(skb, CTA_PROTOINFO_DCCP_ROLE,
 638                        ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]) ||
 639             nla_put_be64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ,
 640                          cpu_to_be64(ct->proto.dccp.handshake_seq),
 641                          CTA_PROTOINFO_DCCP_PAD))
 642                 goto nla_put_failure;
 643         nla_nest_end(skb, nest_parms);
 644         spin_unlock_bh(&ct->lock);
 645         return 0;
 646
 647 nla_put_failure:
 648         spin_unlock_bh(&ct->lock);
 649         return -1;
 650 }
 651
 652 static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
 653         [CTA_PROTOINFO_DCCP_STATE]      = { .type = NLA_U8 },
 654         [CTA_PROTOINFO_DCCP_ROLE]       = { .type = NLA_U8 },
 655         [CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 },
 656         [CTA_PROTOINFO_DCCP_PAD]        = { .type = NLA_UNSPEC },
 657 };
 658
 659 static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
 660 {
 661         struct nlattr *attr = cda[CTA_PROTOINFO_DCCP];
 662         struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1];
 663         int err;
 664
 665         if (!attr)
 666                 return 0;
 667
 668         err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr,
 669                                dccp_nla_policy);
 670         if (err < 0)
 671                 return err;
 672
 673         if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
 674             !tb[CTA_PROTOINFO_DCCP_ROLE] ||
 675             nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX ||
 676             nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) {
 677                 return -EINVAL;
 678         }
 679
 680         spin_lock_bh(&ct->lock);
 681         ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
 682         if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) {
 683                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
 684                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
 685         } else {
 686                 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
 687                 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
 688         }
 689         if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) {
 690                 ct->proto.dccp.handshake_seq =
 691                 be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]));
 692         }
 693         spin_unlock_bh(&ct->lock);
 694         return 0;
 695 }
 696
 697 static int dccp_nlattr_size(void)
 698 {
 699         return nla_total_size(0)        /* CTA_PROTOINFO_DCCP */
 700                 + nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
 701 }
 702
 703 #endif
 704
 705 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 706
 707 #include <linux/netfilter/nfnetlink.h>
 708 #include <linux/netfilter/nfnetlink_cttimeout.h>
 709
 710 static int dccp_timeout_nlattr_to_obj(struct nlattr *tb[],
 711                                       struct net *net, void *data)
 712 {
 713         struct nf_dccp_net *dn = dccp_pernet(net);
 714         unsigned int *timeouts = data;
 715         int i;
 716
 717         /* set default DCCP timeouts. */
 718         for (i=0; i<CT_DCCP_MAX; i++)
 719                 timeouts[i] = dn->dccp_timeout[i];
 720
 721         /* there's a 1:1 mapping between attributes and protocol states. */
 722         for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) {
 723                 if (tb[i]) {
 724                         timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
 725                 }
 726         }
 727         return 0;
 728 }
 729
 730 static int
 731 dccp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 732 {
 733         const unsigned int *timeouts = data;
 734         int i;
 735
 736         for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) {
 737                 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
 738                         goto nla_put_failure;
 739         }
 740         return 0;
 741
 742 nla_put_failure:
 743         return -ENOSPC;
 744 }
 745
 746 static const struct nla_policy
 747 dccp_timeout_nla_policy[CTA_TIMEOUT_DCCP_MAX+1] = {
 748         [CTA_TIMEOUT_DCCP_REQUEST]      = { .type = NLA_U32 },
 749         [CTA_TIMEOUT_DCCP_RESPOND]      = { .type = NLA_U32 },
 750         [CTA_TIMEOUT_DCCP_PARTOPEN]     = { .type = NLA_U32 },
 751         [CTA_TIMEOUT_DCCP_OPEN]         = { .type = NLA_U32 },
 752         [CTA_TIMEOUT_DCCP_CLOSEREQ]     = { .type = NLA_U32 },
 753         [CTA_TIMEOUT_DCCP_CLOSING]      = { .type = NLA_U32 },
 754         [CTA_TIMEOUT_DCCP_TIMEWAIT]     = { .type = NLA_U32 },
 755 };
 756 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 757
 758 #ifdef CONFIG_SYSCTL
 759 /* template, data assigned later */
 760 static struct ctl_table dccp_sysctl_table[] = {
 761         {
 762                 .procname       = "nf_conntrack_dccp_timeout_request",
 763                 .maxlen         = sizeof(unsigned int),
 764                 .mode           = 0644,
 765                 .proc_handler   = proc_dointvec_jiffies,
 766         },
 767         {
 768                 .procname       = "nf_conntrack_dccp_timeout_respond",
 769                 .maxlen         = sizeof(unsigned int),
 770                 .mode           = 0644,
 771                 .proc_handler   = proc_dointvec_jiffies,
 772         },
 773         {
 774                 .procname       = "nf_conntrack_dccp_timeout_partopen",
 775                 .maxlen         = sizeof(unsigned int),
 776                 .mode           = 0644,
 777                 .proc_handler   = proc_dointvec_jiffies,
 778         },
 779         {
 780                 .procname       = "nf_conntrack_dccp_timeout_open",
 781                 .maxlen         = sizeof(unsigned int),
 782                 .mode           = 0644,
 783                 .proc_handler   = proc_dointvec_jiffies,
 784         },
 785         {
 786                 .procname       = "nf_conntrack_dccp_timeout_closereq",
 787                 .maxlen         = sizeof(unsigned int),
 788                 .mode           = 0644,
 789                 .proc_handler   = proc_dointvec_jiffies,
 790         },
 791         {
 792                 .procname       = "nf_conntrack_dccp_timeout_closing",
 793                 .maxlen         = sizeof(unsigned int),
 794                 .mode           = 0644,
 795                 .proc_handler   = proc_dointvec_jiffies,
 796         },
 797         {
 798                 .procname       = "nf_conntrack_dccp_timeout_timewait",
 799                 .maxlen         = sizeof(unsigned int),
 800                 .mode           = 0644,
 801                 .proc_handler   = proc_dointvec_jiffies,
 802         },
 803         {
 804                 .procname       = "nf_conntrack_dccp_loose",
 805                 .maxlen         = sizeof(int),
 806                 .mode           = 0644,
 807                 .proc_handler   = proc_dointvec,
 808         },
 809         { }
 810 };
 811 #endif /* CONFIG_SYSCTL */
 812
 813 static int dccp_kmemdup_sysctl_table(struct net *net, struct nf_proto_net *pn,
 814                                      struct nf_dccp_net *dn)
 815 {
 816 #ifdef CONFIG_SYSCTL
 817         if (pn->ctl_table)
 818                 return 0;
 819
 820         pn->ctl_table = kmemdup(dccp_sysctl_table,
 821                                 sizeof(dccp_sysctl_table),
 822                                 GFP_KERNEL);
 823         if (!pn->ctl_table)
 824                 return -ENOMEM;
 825
 826         pn->ctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST];
 827         pn->ctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND];
 828         pn->ctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN];
 829         pn->ctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN];
 830         pn->ctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ];
 831         pn->ctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
 832         pn->ctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
 833         pn->ctl_table[7].data = &dn->dccp_loose;
 834
 835         /* Don't export sysctls to unprivileged users */
 836         if (net->user_ns != &init_user_ns)
 837                 pn->ctl_table[0].procname = NULL;
 838 #endif
 839         return 0;
 840 }
 841
 842 static int dccp_init_net(struct net *net, u_int16_t proto)
 843 {
 844         struct nf_dccp_net *dn = dccp_pernet(net);
 845         struct nf_proto_net *pn = &dn->pn;
 846
 847         if (!pn->users) {
 848                 /* default values */
 849                 dn->dccp_loose = 1;
 850                 dn->dccp_timeout[CT_DCCP_REQUEST]       = 2 * DCCP_MSL;
 851                 dn->dccp_timeout[CT_DCCP_RESPOND]       = 4 * DCCP_MSL;
 852                 dn->dccp_timeout[CT_DCCP_PARTOPEN]      = 4 * DCCP_MSL;
 853                 dn->dccp_timeout[CT_DCCP_OPEN]          = 12 * 3600 * HZ;
 854                 dn->dccp_timeout[CT_DCCP_CLOSEREQ]      = 64 * HZ;
 855                 dn->dccp_timeout[CT_DCCP_CLOSING]       = 64 * HZ;
 856                 dn->dccp_timeout[CT_DCCP_TIMEWAIT]      = 2 * DCCP_MSL;
 857         }
 858
 859         return dccp_kmemdup_sysctl_table(net, pn, dn);
 860 }
 861
 862 struct nf_conntrack_l4proto nf_conntrack_l4proto_dccp4 __read_mostly = {
 863         .l3proto                = AF_INET,
 864         .l4proto                = IPPROTO_DCCP,
 865         .name                   = "dccp",
 866         .pkt_to_tuple           = dccp_pkt_to_tuple,
 867         .invert_tuple           = dccp_invert_tuple,
 868         .new                    = dccp_new,
 869         .packet                 = dccp_packet,
 870         .get_timeouts           = dccp_get_timeouts,
 871         .error                  = dccp_error,
 872         .print_tuple            = dccp_print_tuple,
 873         .print_conntrack        = dccp_print_conntrack,
 874 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 875         .to_nlattr              = dccp_to_nlattr,
 876         .nlattr_size            = dccp_nlattr_size,
 877         .from_nlattr            = nlattr_to_dccp,
 878         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 879         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 880         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 881         .nla_policy             = nf_ct_port_nla_policy,
 882 #endif
 883 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 884         .ctnl_timeout           = {
 885                 .nlattr_to_obj  = dccp_timeout_nlattr_to_obj,
 886                 .obj_to_nlattr  = dccp_timeout_obj_to_nlattr,
 887                 .nlattr_max     = CTA_TIMEOUT_DCCP_MAX,
 888                 .obj_size       = sizeof(unsigned int) * CT_DCCP_MAX,
 889                 .nla_policy     = dccp_timeout_nla_policy,
 890         },
 891 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 892         .init_net               = dccp_init_net,
 893 };
 894 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_dccp4);
 895
 896 struct nf_conntrack_l4proto nf_conntrack_l4proto_dccp6 __read_mostly = {
 897         .l3proto                = AF_INET6,
 898         .l4proto                = IPPROTO_DCCP,
 899         .name                   = "dccp",
 900         .pkt_to_tuple           = dccp_pkt_to_tuple,
 901         .invert_tuple           = dccp_invert_tuple,
 902         .new                    = dccp_new,
 903         .packet                 = dccp_packet,
 904         .get_timeouts           = dccp_get_timeouts,
 905         .error                  = dccp_error,
 906         .print_tuple            = dccp_print_tuple,
 907         .print_conntrack        = dccp_print_conntrack,
 908 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 909         .to_nlattr              = dccp_to_nlattr,
 910         .nlattr_size            = dccp_nlattr_size,
 911         .from_nlattr            = nlattr_to_dccp,
 912         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 913         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 914         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 915         .nla_policy             = nf_ct_port_nla_policy,
 916 #endif
 917 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 918         .ctnl_timeout           = {
 919                 .nlattr_to_obj  = dccp_timeout_nlattr_to_obj,
 920                 .obj_to_nlattr  = dccp_timeout_obj_to_nlattr,
 921                 .nlattr_max     = CTA_TIMEOUT_DCCP_MAX,
 922                 .obj_size       = sizeof(unsigned int) * CT_DCCP_MAX,
 923                 .nla_policy     = dccp_timeout_nla_policy,
 924         },
 925 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 926         .init_net               = dccp_init_net,
 927 };
 928 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_dccp6);