linux/net/netfilter/nf_conntrack_proto_dccp.c
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   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
  76static 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 */
 132static const u_int8_t
 133dccp_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 */
 388static int dccp_net_id __read_mostly;
 389struct 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
 398static inline struct dccp_net *dccp_pernet(struct net *net)
 399{
 400        return net_generic(net, dccp_net_id);
 401}
 402
 403static 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
 417static 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
 425static 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
 460out_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
 466static 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
 475static 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
 568static 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
 613out_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
 619static 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
 627static 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 IS_ENABLED(CONFIG_NF_CT_NETLINK)
 633static 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
 651nla_put_failure:
 652        spin_unlock_bh(&ct->lock);
 653        return -1;
 654}
 655
 656static 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
 662static 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
 700static 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 */
 709static 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
 762static 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 IS_ENABLED(CONFIG_NF_CT_NETLINK)
 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
 784static 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 IS_ENABLED(CONFIG_NF_CT_NETLINK)
 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
 806static __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
 846static __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
 855static 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
 862static 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
 879err3:
 880        nf_conntrack_l4proto_unregister(&dccp_proto4);
 881err2:
 882        unregister_pernet_subsys(&dccp_net_ops);
 883err1:
 884        return err;
 885}
 886
 887static 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
 894module_init(nf_conntrack_proto_dccp_init);
 895module_exit(nf_conntrack_proto_dccp_fini);
 896
 897MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 898MODULE_DESCRIPTION("DCCP connection tracking protocol helper");
 899MODULE_LICENSE("GPL");
 900
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