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   1 /*
   2  *  net/dccp/input.c
   3  *
   4  *  An implementation of the DCCP protocol
   5  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/dccp.h>
  15 #include <linux/skbuff.h>
  16
  17 #include <net/sock.h>
  18
  19 #include "ackvec.h"
  20 #include "ccid.h"
  21 #include "dccp.h"
  22
  23 static void dccp_fin(struct sock *sk, struct sk_buff *skb)
  24 {
  25         sk->sk_shutdown |= RCV_SHUTDOWN;
  26         sock_set_flag(sk, SOCK_DONE);
  27         __skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
  28         __skb_queue_tail(&sk->sk_receive_queue, skb);
  29         skb_set_owner_r(skb, sk);
  30         sk->sk_data_ready(sk, 0);
  31 }
  32
  33 static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
  34 {
  35         dccp_v4_send_reset(sk, DCCP_RESET_CODE_CLOSED);
  36         dccp_fin(sk, skb);
  37         dccp_set_state(sk, DCCP_CLOSED);
  38         sk_wake_async(sk, 1, POLL_HUP);
  39 }
  40
  41 static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
  42 {
  43         /*
  44          *   Step 7: Check for unexpected packet types
  45          *      If (S.is_server and P.type == CloseReq)
  46          *        Send Sync packet acknowledging P.seqno
  47          *        Drop packet and return
  48          */
  49         if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
  50                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
  51                 return;
  52         }
  53
  54         if (sk->sk_state != DCCP_CLOSING)
  55                 dccp_set_state(sk, DCCP_CLOSING);
  56         dccp_send_close(sk, 0);
  57 }
  58
  59 static inline void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
  60 {
  61         struct dccp_sock *dp = dccp_sk(sk);
  62
  63         if (dp->dccps_options.dccpo_send_ack_vector)
  64                 dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
  65                                             DCCP_SKB_CB(skb)->dccpd_ack_seq);
  66 }
  67
  68 static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
  69 {
  70         const struct dccp_hdr *dh = dccp_hdr(skb);
  71         struct dccp_sock *dp = dccp_sk(sk);
  72         u64 lswl, lawl;
  73
  74         /*
  75          *   Step 5: Prepare sequence numbers for Sync
  76          *     If P.type == Sync or P.type == SyncAck,
  77          *        If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
  78          *           / * P is valid, so update sequence number variables
  79          *               accordingly.  After this update, P will pass the tests
  80          *               in Step 6.  A SyncAck is generated if necessary in
  81          *               Step 15 * /
  82          *           Update S.GSR, S.SWL, S.SWH
  83          *        Otherwise,
  84          *           Drop packet and return
  85          */
  86         if (dh->dccph_type == DCCP_PKT_SYNC ||
  87             dh->dccph_type == DCCP_PKT_SYNCACK) {
  88                 if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
  89                               dp->dccps_awl, dp->dccps_awh) &&
  90                     !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
  91                         dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
  92                 else
  93                         return -1;
  94         }
  95
  96         /*
  97          *   Step 6: Check sequence numbers
  98          *      Let LSWL = S.SWL and LAWL = S.AWL
  99          *      If P.type == CloseReq or P.type == Close or P.type == Reset,
 100          *        LSWL := S.GSR + 1, LAWL := S.GAR
 101          *      If LSWL <= P.seqno <= S.SWH
 102          *           and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
 103          *        Update S.GSR, S.SWL, S.SWH
 104          *        If P.type != Sync,
 105          *           Update S.GAR
 106          *      Otherwise,
 107          *        Send Sync packet acknowledging P.seqno
 108          *        Drop packet and return
 109          */
 110         lswl = dp->dccps_swl;
 111         lawl = dp->dccps_awl;
 112
 113         if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
 114             dh->dccph_type == DCCP_PKT_CLOSE ||
 115             dh->dccph_type == DCCP_PKT_RESET) {
 116                 lswl = dp->dccps_gsr;
 117                 dccp_inc_seqno(&lswl);
 118                 lawl = dp->dccps_gar;
 119         }
 120
 121         if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
 122             (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ ||
 123              between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
 124                        lawl, dp->dccps_awh))) {
 125                 dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
 126
 127                 if (dh->dccph_type != DCCP_PKT_SYNC &&
 128                     (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
 129                      DCCP_PKT_WITHOUT_ACK_SEQ))
 130                         dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
 131         } else {
 132                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: Step 6 failed for %s packet, "
 133                                             "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
 134                                             "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
 135                                             "sending SYNC...\n",
 136                                dccp_packet_name(dh->dccph_type),
 137                                (unsigned long long) lswl,
 138                                (unsigned long long)
 139                                DCCP_SKB_CB(skb)->dccpd_seq,
 140                                (unsigned long long) dp->dccps_swh,
 141                                (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
 142                                 DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
 143                                (unsigned long long) lawl,
 144                                (unsigned long long)
 145                                DCCP_SKB_CB(skb)->dccpd_ack_seq,
 146                                (unsigned long long) dp->dccps_awh);
 147                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
 148                 return -1;
 149         }
 150
 151         return 0;
 152 }
 153
 154 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 155                          const struct dccp_hdr *dh, const unsigned len)
 156 {
 157         struct dccp_sock *dp = dccp_sk(sk);
 158
 159         if (dccp_check_seqno(sk, skb))
 160                 goto discard;
 161
 162         if (dccp_parse_options(sk, skb))
 163                 goto discard;
 164
 165         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
 166                 dccp_event_ack_recv(sk, skb);
 167
 168         if (dp->dccps_options.dccpo_send_ack_vector &&
 169             dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
 170                             DCCP_SKB_CB(skb)->dccpd_seq,
 171                             DCCP_ACKVEC_STATE_RECEIVED))
 172                 goto discard;
 173
 174         ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
 175         ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
 176
 177         switch (dccp_hdr(skb)->dccph_type) {
 178         case DCCP_PKT_DATAACK:
 179         case DCCP_PKT_DATA:
 180                 /*
 181                  * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
 182                  * option if it is.
 183                  */
 184                 __skb_pull(skb, dh->dccph_doff * 4);
 185                 __skb_queue_tail(&sk->sk_receive_queue, skb);
 186                 skb_set_owner_r(skb, sk);
 187                 sk->sk_data_ready(sk, 0);
 188                 return 0;
 189         case DCCP_PKT_ACK:
 190                 goto discard;
 191         case DCCP_PKT_RESET:
 192                 /*
 193                  *  Step 9: Process Reset
 194                  *      If P.type == Reset,
 195                  *              Tear down connection
 196                  *              S.state := TIMEWAIT
 197                  *              Set TIMEWAIT timer
 198                  *              Drop packet and return
 199                 */
 200                 dccp_fin(sk, skb);
 201                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
 202                 return 0;
 203         case DCCP_PKT_CLOSEREQ:
 204                 dccp_rcv_closereq(sk, skb);
 205                 goto discard;
 206         case DCCP_PKT_CLOSE:
 207                 dccp_rcv_close(sk, skb);
 208                 return 0;
 209         case DCCP_PKT_REQUEST:
 210                 /* Step 7
 211                  *   or (S.is_server and P.type == Response)
 212                  *   or (S.is_client and P.type == Request)
 213                  *   or (S.state >= OPEN and P.type == Request
 214                  *      and P.seqno >= S.OSR)
 215                  *    or (S.state >= OPEN and P.type == Response
 216                  *      and P.seqno >= S.OSR)
 217                  *    or (S.state == RESPOND and P.type == Data),
 218                  *  Send Sync packet acknowledging P.seqno
 219                  *  Drop packet and return
 220                  */
 221                 if (dp->dccps_role != DCCP_ROLE_LISTEN)
 222                         goto send_sync;
 223                 goto check_seq;
 224         case DCCP_PKT_RESPONSE:
 225                 if (dp->dccps_role != DCCP_ROLE_CLIENT)
 226                         goto send_sync;
 227 check_seq:
 228                 if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
 229 send_sync:
 230                         dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
 231                                        DCCP_PKT_SYNC);
 232                 }
 233                 break;
 234         case DCCP_PKT_SYNC:
 235                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
 236                                DCCP_PKT_SYNCACK);
 237                 /*
 238                  * From the draft:
 239                  *
 240                  * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
 241                  * MAY have non-zero-length application data areas, whose
 242                  * contents * receivers MUST ignore.
 243                  */
 244                 goto discard;
 245         }
 246
 247         DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
 248 discard:
 249         __kfree_skb(skb);
 250         return 0;
 251 }
 252
 253 EXPORT_SYMBOL_GPL(dccp_rcv_established);
 254
 255 static int dccp_rcv_request_sent_state_process(struct sock *sk,
 256                                                struct sk_buff *skb,
 257                                                const struct dccp_hdr *dh,
 258                                                const unsigned len)
 259 {
 260         /*
 261          *  Step 4: Prepare sequence numbers in REQUEST
 262          *     If S.state == REQUEST,
 263          *        If (P.type == Response or P.type == Reset)
 264          *              and S.AWL <= P.ackno <= S.AWH,
 265          *           / * Set sequence number variables corresponding to the
 266          *              other endpoint, so P will pass the tests in Step 6 * /
 267          *           Set S.GSR, S.ISR, S.SWL, S.SWH
 268          *           / * Response processing continues in Step 10; Reset
 269          *              processing continues in Step 9 * /
 270         */
 271         if (dh->dccph_type == DCCP_PKT_RESPONSE) {
 272                 const struct inet_connection_sock *icsk = inet_csk(sk);
 273                 struct dccp_sock *dp = dccp_sk(sk);
 274
 275                 /* Stop the REQUEST timer */
 276                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
 277                 BUG_TRAP(sk->sk_send_head != NULL);
 278                 __kfree_skb(sk->sk_send_head);
 279                 sk->sk_send_head = NULL;
 280
 281                 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
 282                                dp->dccps_awl, dp->dccps_awh)) {
 283                         dccp_pr_debug("invalid ackno: S.AWL=%llu, "
 284                                       "P.ackno=%llu, S.AWH=%llu \n",
 285                                       (unsigned long long)dp->dccps_awl,
 286                            (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
 287                                       (unsigned long long)dp->dccps_awh);
 288                         goto out_invalid_packet;
 289                 }
 290
 291                 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
 292                 dccp_update_gsr(sk, dp->dccps_isr);
 293                 /*
 294                  * SWL and AWL are initially adjusted so that they are not less than
 295                  * the initial Sequence Numbers received and sent, respectively:
 296                  *      SWL := max(GSR + 1 - floor(W/4), ISR),
 297                  *      AWL := max(GSS - W' + 1, ISS).
 298                  * These adjustments MUST be applied only at the beginning of the
 299                  * connection.
 300                  *
 301                  * AWL was adjusted in dccp_v4_connect -acme
 302                  */
 303                 dccp_set_seqno(&dp->dccps_swl,
 304                                max48(dp->dccps_swl, dp->dccps_isr));
 305
 306                 if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 ||
 307                     ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
 308                         ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
 309                         ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
 310                         /* FIXME: send appropriate RESET code */
 311                         goto out_invalid_packet;
 312                 }
 313
 314                 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
 315
 316                 /*
 317                  *    Step 10: Process REQUEST state (second part)
 318                  *       If S.state == REQUEST,
 319                  *        / * If we get here, P is a valid Response from the
 320                  *            server (see Step 4), and we should move to
 321                  *            PARTOPEN state. PARTOPEN means send an Ack,
 322                  *            don't send Data packets, retransmit Acks
 323                  *            periodically, and always include any Init Cookie
 324                  *            from the Response * /
 325                  *        S.state := PARTOPEN
 326                  *        Set PARTOPEN timer
 327                  *        Continue with S.state == PARTOPEN
 328                  *        / * Step 12 will send the Ack completing the
 329                  *            three-way handshake * /
 330                  */
 331                 dccp_set_state(sk, DCCP_PARTOPEN);
 332
 333                 /* Make sure socket is routed, for correct metrics. */
 334                 icsk->icsk_af_ops->rebuild_header(sk);
 335
 336                 if (!sock_flag(sk, SOCK_DEAD)) {
 337                         sk->sk_state_change(sk);
 338                         sk_wake_async(sk, 0, POLL_OUT);
 339                 }
 340
 341                 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
 342                     icsk->icsk_accept_queue.rskq_defer_accept) {
 343                         /* Save one ACK. Data will be ready after
 344                          * several ticks, if write_pending is set.
 345                          *
 346                          * It may be deleted, but with this feature tcpdumps
 347                          * look so _wonderfully_ clever, that I was not able
 348                          * to stand against the temptation 8)     --ANK
 349                          */
 350                         /*
 351                          * OK, in DCCP we can as well do a similar trick, its
 352                          * even in the draft, but there is no need for us to
 353                          * schedule an ack here, as dccp_sendmsg does this for
 354                          * us, also stated in the draft. -acme
 355                          */
 356                         __kfree_skb(skb);
 357                         return 0;
 358                 }
 359                 dccp_send_ack(sk);
 360                 return -1;
 361         }
 362
 363 out_invalid_packet:
 364         /* dccp_v4_do_rcv will send a reset */
 365         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
 366         return 1;
 367 }
 368
 369 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
 370                                                    struct sk_buff *skb,
 371                                                    const struct dccp_hdr *dh,
 372                                                    const unsigned len)
 373 {
 374         int queued = 0;
 375
 376         switch (dh->dccph_type) {
 377         case DCCP_PKT_RESET:
 378                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
 379                 break;
 380         case DCCP_PKT_DATA:
 381                 if (sk->sk_state == DCCP_RESPOND)
 382                         break;
 383         case DCCP_PKT_DATAACK:
 384         case DCCP_PKT_ACK:
 385                 /*
 386                  * FIXME: we should be reseting the PARTOPEN (DELACK) timer
 387                  * here but only if we haven't used the DELACK timer for
 388                  * something else, like sending a delayed ack for a TIMESTAMP
 389                  * echo, etc, for now were not clearing it, sending an extra
 390                  * ACK when there is nothing else to do in DELACK is not a big
 391                  * deal after all.
 392                  */
 393
 394                 /* Stop the PARTOPEN timer */
 395                 if (sk->sk_state == DCCP_PARTOPEN)
 396                         inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
 397
 398                 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
 399                 dccp_set_state(sk, DCCP_OPEN);
 400
 401                 if (dh->dccph_type == DCCP_PKT_DATAACK ||
 402                     dh->dccph_type == DCCP_PKT_DATA) {
 403                         dccp_rcv_established(sk, skb, dh, len);
 404                         queued = 1; /* packet was queued
 405                                        (by dccp_rcv_established) */
 406                 }
 407                 break;
 408         }
 409
 410         return queued;
 411 }
 412
 413 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 414                            struct dccp_hdr *dh, unsigned len)
 415 {
 416         struct dccp_sock *dp = dccp_sk(sk);
 417         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
 418         const int old_state = sk->sk_state;
 419         int queued = 0;
 420
 421         /*
 422          *  Step 3: Process LISTEN state
 423          *      (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
 424          *
 425          *     If S.state == LISTEN,
 426          *        If P.type == Request or P contains a valid Init Cookie
 427          *              option,
 428          *           * Must scan the packet's options to check for an Init
 429          *              Cookie.  Only the Init Cookie is processed here,
 430          *              however; other options are processed in Step 8.  This
 431          *              scan need only be performed if the endpoint uses Init
 432          *              Cookies *
 433          *           * Generate a new socket and switch to that socket *
 434          *           Set S := new socket for this port pair
 435          *           S.state = RESPOND
 436          *           Choose S.ISS (initial seqno) or set from Init Cookie
 437          *           Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
 438          *           Continue with S.state == RESPOND
 439          *           * A Response packet will be generated in Step 11 *
 440          *        Otherwise,
 441          *           Generate Reset(No Connection) unless P.type == Reset
 442          *           Drop packet and return
 443          *
 444          * NOTE: the check for the packet types is done in
 445          *       dccp_rcv_state_process
 446          */
 447         if (sk->sk_state == DCCP_LISTEN) {
 448                 if (dh->dccph_type == DCCP_PKT_REQUEST) {
 449                         if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
 450                                                                     skb) < 0)
 451                                 return 1;
 452
 453                         /* FIXME: do congestion control initialization */
 454                         goto discard;
 455                 }
 456                 if (dh->dccph_type == DCCP_PKT_RESET)
 457                         goto discard;
 458
 459                 /* Caller (dccp_v4_do_rcv) will send Reset */
 460                 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
 461                 return 1;
 462         }
 463
 464         if (sk->sk_state != DCCP_REQUESTING) {
 465                 if (dccp_check_seqno(sk, skb))
 466                         goto discard;
 467
 468                 /*
 469                  * Step 8: Process options and mark acknowledgeable
 470                  */
 471                 if (dccp_parse_options(sk, skb))
 472                         goto discard;
 473
 474                 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
 475                         dccp_event_ack_recv(sk, skb);
 476
 477                 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
 478                 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
 479
 480                 if (dp->dccps_options.dccpo_send_ack_vector &&
 481                     dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
 482                                     DCCP_SKB_CB(skb)->dccpd_seq,
 483                                     DCCP_ACKVEC_STATE_RECEIVED))
 484                         goto discard;
 485         }
 486
 487         /*
 488          *  Step 9: Process Reset
 489          *      If P.type == Reset,
 490          *              Tear down connection
 491          *              S.state := TIMEWAIT
 492          *              Set TIMEWAIT timer
 493          *              Drop packet and return
 494         */
 495         if (dh->dccph_type == DCCP_PKT_RESET) {
 496                 /*
 497                  * Queue the equivalent of TCP fin so that dccp_recvmsg
 498                  * exits the loop
 499                  */
 500                 dccp_fin(sk, skb);
 501                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
 502                 return 0;
 503                 /*
 504                  *   Step 7: Check for unexpected packet types
 505                  *      If (S.is_server and P.type == CloseReq)
 506                  *          or (S.is_server and P.type == Response)
 507                  *          or (S.is_client and P.type == Request)
 508                  *          or (S.state == RESPOND and P.type == Data),
 509                  *        Send Sync packet acknowledging P.seqno
 510                  *        Drop packet and return
 511                  */
 512         } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
 513                     (dh->dccph_type == DCCP_PKT_RESPONSE ||
 514                      dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
 515                     (dp->dccps_role == DCCP_ROLE_CLIENT &&
 516                      dh->dccph_type == DCCP_PKT_REQUEST) ||
 517                     (sk->sk_state == DCCP_RESPOND &&
 518                      dh->dccph_type == DCCP_PKT_DATA)) {
 519                 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
 520                 goto discard;
 521         } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
 522                 dccp_rcv_closereq(sk, skb);
 523                 goto discard;
 524         } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
 525                 dccp_rcv_close(sk, skb);
 526                 return 0;
 527         }
 528
 529         if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
 530                 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
 531                 goto discard;
 532         }
 533
 534         switch (sk->sk_state) {
 535         case DCCP_CLOSED:
 536                 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
 537                 return 1;
 538
 539         case DCCP_REQUESTING:
 540                 /* FIXME: do congestion control initialization */
 541
 542                 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
 543                 if (queued >= 0)
 544                         return queued;
 545
 546                 __kfree_skb(skb);
 547                 return 0;
 548
 549         case DCCP_RESPOND:
 550         case DCCP_PARTOPEN:
 551                 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
 552                                                                  dh, len);
 553                 break;
 554         }
 555
 556         if (dh->dccph_type == DCCP_PKT_ACK ||
 557             dh->dccph_type == DCCP_PKT_DATAACK) {
 558                 switch (old_state) {
 559                 case DCCP_PARTOPEN:
 560                         sk->sk_state_change(sk);
 561                         sk_wake_async(sk, 0, POLL_OUT);
 562                         break;
 563                 }
 564         }
 565
 566         if (!queued) {
 567 discard:
 568                 __kfree_skb(skb);
 569         }
 570         return 0;
 571 }
 572
 573 EXPORT_SYMBOL_GPL(dccp_rcv_state_process);