net/dccp/input.c

   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 "ccid.h"
  20 #include "dccp.h"
  21
  22 static void dccp_fin(struct sock *sk, struct sk_buff *skb)
  23 {
  24         sk->sk_shutdown |= RCV_SHUTDOWN;
  25         sock_set_flag(sk, SOCK_DONE);
  26         __skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
  27         __skb_queue_tail(&sk->sk_receive_queue, skb);
  28         skb_set_owner_r(skb, sk);
  29         sk->sk_data_ready(sk, 0);
  30 }
  31
  32 static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
  33 {
  34         switch (sk->sk_state) {
  35         case DCCP_PARTOPEN:
  36         case DCCP_OPEN:
  37                 dccp_v4_send_reset(sk, DCCP_RESET_CODE_CLOSED);
  38                 dccp_fin(sk, skb);
  39                 dccp_set_state(sk, DCCP_CLOSED);
  40                 break;
  41         }
  42 }
  43
  44 static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
  45 {
  46         /*
  47          *   Step 7: Check for unexpected packet types
  48          *      If (S.is_server and P.type == CloseReq)
  49          *        Send Sync packet acknowledging P.seqno
  50          *        Drop packet and return
  51          */
  52         if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
  53                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
  54                 return;
  55         }
  56
  57         switch (sk->sk_state) {
  58         case DCCP_PARTOPEN:
  59         case DCCP_OPEN:
  60                 dccp_set_state(sk, DCCP_CLOSING);
  61                 dccp_send_close(sk);
  62                 break;
  63         }
  64 }
  65
  66 static inline void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
  67 {
  68         struct dccp_sock *dp = dccp_sk(sk);
  69
  70         if (dp->dccps_options.dccpo_send_ack_vector)
  71                 dccp_ackpkts_check_rcv_ackno(dp->dccps_hc_rx_ackpkts, sk,
  72                                              DCCP_SKB_CB(skb)->dccpd_ack_seq);
  73 }
  74
  75 static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
  76 {
  77         const struct dccp_hdr *dh = dccp_hdr(skb);
  78         struct dccp_sock *dp = dccp_sk(sk);
  79         u64 lswl, lawl;
  80
  81         /*
  82          *   Step 5: Prepare sequence numbers for Sync
  83          *     If P.type == Sync or P.type == SyncAck,
  84          *        If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
  85          *           / * P is valid, so update sequence number variables
  86          *               accordingly.  After this update, P will pass the tests
  87          *               in Step 6.  A SyncAck is generated if necessary in
  88          *               Step 15 * /
  89          *           Update S.GSR, S.SWL, S.SWH
  90          *        Otherwise,
  91          *           Drop packet and return
  92          */
  93         if (dh->dccph_type == DCCP_PKT_SYNC ||
  94             dh->dccph_type == DCCP_PKT_SYNCACK) {
  95                 if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
  96                               dp->dccps_awl, dp->dccps_awh) &&
  97                     !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
  98                         dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
  99                 else
 100                         return -1;
 101         }
 102
 103         /*
 104          *   Step 6: Check sequence numbers
 105          *      Let LSWL = S.SWL and LAWL = S.AWL
 106          *      If P.type == CloseReq or P.type == Close or P.type == Reset,
 107          *        LSWL := S.GSR + 1, LAWL := S.GAR
 108          *      If LSWL <= P.seqno <= S.SWH
 109          *           and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
 110          *        Update S.GSR, S.SWL, S.SWH
 111          *        If P.type != Sync,
 112          *           Update S.GAR
 113          *      Otherwise,
 114          *        Send Sync packet acknowledging P.seqno
 115          *        Drop packet and return
 116          */
 117         lswl = dp->dccps_swl;
 118         lawl = dp->dccps_awl;
 119
 120         if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
 121                    dh->dccph_type == DCCP_PKT_CLOSE ||
 122                    dh->dccph_type == DCCP_PKT_RESET) {
 123                 lswl = dp->dccps_gsr;
 124                 dccp_inc_seqno(&lswl);
 125                 lawl = dp->dccps_gar;
 126         }
 127
 128         if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
 129             (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ ||
 130              between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
 131                        lawl, dp->dccps_awh))) {
 132                 dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
 133
 134                 if (dh->dccph_type != DCCP_PKT_SYNC &&
 135                     (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
 136                      DCCP_PKT_WITHOUT_ACK_SEQ))
 137                         dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
 138         } else {
 139                 LIMIT_NETDEBUG("Step 6 failed, sending SYNC...\n");
 140                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
 141                 return -1;
 142         }
 143
 144         return 0;
 145 }
 146
 147 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 148                          const struct dccp_hdr *dh, const unsigned len)
 149 {
 150         struct dccp_sock *dp = dccp_sk(sk);
 151
 152         if (dccp_check_seqno(sk, skb))
 153                 goto discard;
 154
 155         if (dccp_parse_options(sk, skb))
 156                 goto discard;
 157
 158         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
 159                 dccp_event_ack_recv(sk, skb);
 160
 161         /*
 162          * FIXME: check ECN to see if we should use
 163          * DCCP_ACKPKTS_STATE_ECN_MARKED
 164          */
 165         if (dp->dccps_options.dccpo_send_ack_vector) {
 166                 struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
 167
 168                 if (dccp_ackpkts_add(dp->dccps_hc_rx_ackpkts,
 169                                      DCCP_SKB_CB(skb)->dccpd_seq,
 170                                      DCCP_ACKPKTS_STATE_RECEIVED)) {
 171                         LIMIT_NETDEBUG(KERN_INFO "DCCP: acknowledgeable "
 172                                                  "packets buffer full!\n");
 173                         ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
 174                         inet_csk_schedule_ack(sk);
 175                         inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
 176                                                   TCP_DELACK_MIN,
 177                                                   DCCP_RTO_MAX);
 178                         goto discard;
 179                 }
 180
 181                 /*
 182                  * FIXME: this activation is probably wrong, have to study more
 183                  * TCP delack machinery and how it fits into DCCP draft, but
 184                  * for now it kinda "works" 8)
 185                  */
 186                 if (!inet_csk_ack_scheduled(sk)) {
 187                         inet_csk_schedule_ack(sk);
 188                         inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 5 * HZ,
 189                                                   DCCP_RTO_MAX);
 190                 }
 191         }
 192
 193         ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
 194         ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
 195
 196         switch (dccp_hdr(skb)->dccph_type) {
 197         case DCCP_PKT_DATAACK:
 198         case DCCP_PKT_DATA:
 199                 /*
 200                  * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
 201                  * option if it is.
 202                  */
 203                 __skb_pull(skb, dh->dccph_doff * 4);
 204                 __skb_queue_tail(&sk->sk_receive_queue, skb);
 205                 skb_set_owner_r(skb, sk);
 206                 sk->sk_data_ready(sk, 0);
 207                 return 0;
 208         case DCCP_PKT_ACK:
 209                 goto discard;
 210         case DCCP_PKT_RESET:
 211                 /*
 212                  *  Step 9: Process Reset
 213                  *      If P.type == Reset,
 214                  *              Tear down connection
 215                  *              S.state := TIMEWAIT
 216                  *              Set TIMEWAIT timer
 217                  *              Drop packet and return
 218                 */
 219                 dccp_fin(sk, skb);
 220                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
 221                 return 0;
 222         case DCCP_PKT_CLOSEREQ:
 223                 dccp_rcv_closereq(sk, skb);
 224                 goto discard;
 225         case DCCP_PKT_CLOSE:
 226                 dccp_rcv_close(sk, skb);
 227                 return 0;
 228         case DCCP_PKT_REQUEST:
 229                 /* Step 7
 230                  *   or (S.is_server and P.type == Response)
 231                  *   or (S.is_client and P.type == Request)
 232                  *   or (S.state >= OPEN and P.type == Request
 233                  *      and P.seqno >= S.OSR)
 234                  *    or (S.state >= OPEN and P.type == Response
 235                  *      and P.seqno >= S.OSR)
 236                  *    or (S.state == RESPOND and P.type == Data),
 237                  *  Send Sync packet acknowledging P.seqno
 238                  *  Drop packet and return
 239                  */
 240                 if (dp->dccps_role != DCCP_ROLE_LISTEN)
 241                         goto send_sync;
 242                 goto check_seq;
 243         case DCCP_PKT_RESPONSE:
 244                 if (dp->dccps_role != DCCP_ROLE_CLIENT)
 245                         goto send_sync;
 246 check_seq:
 247                 if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
 248 send_sync:
 249                         dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
 250                                        DCCP_PKT_SYNC);
 251                 }
 252                 break;
 253         case DCCP_PKT_SYNC:
 254                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
 255                                DCCP_PKT_SYNCACK);
 256                 /*
 257                  * From the draft:
 258                  *
 259                  * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
 260                  * MAY have non-zero-length application data areas, whose
 261                  * contents * receivers MUST ignore.
 262                  */
 263                 goto discard;
 264         }
 265
 266         DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
 267 discard:
 268         __kfree_skb(skb);
 269         return 0;
 270 }
 271
 272 static int dccp_rcv_request_sent_state_process(struct sock *sk,
 273                                                struct sk_buff *skb,
 274                                                const struct dccp_hdr *dh,
 275                                                const unsigned len)
 276 {
 277         /*
 278          *  Step 4: Prepare sequence numbers in REQUEST
 279          *     If S.state == REQUEST,
 280          *        If (P.type == Response or P.type == Reset)
 281          *              and S.AWL <= P.ackno <= S.AWH,
 282          *           / * Set sequence number variables corresponding to the
 283          *              other endpoint, so P will pass the tests in Step 6 * /
 284          *           Set S.GSR, S.ISR, S.SWL, S.SWH
 285          *           / * Response processing continues in Step 10; Reset
 286          *              processing continues in Step 9 * /
 287         */
 288         if (dh->dccph_type == DCCP_PKT_RESPONSE) {
 289                 const struct inet_connection_sock *icsk = inet_csk(sk);
 290                 struct dccp_sock *dp = dccp_sk(sk);
 291
 292                 /* Stop the REQUEST timer */
 293                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
 294                 BUG_TRAP(sk->sk_send_head != NULL);
 295                 __kfree_skb(sk->sk_send_head);
 296                 sk->sk_send_head = NULL;
 297
 298                 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
 299                                dp->dccps_awl, dp->dccps_awh)) {
 300                         dccp_pr_debug("invalid ackno: S.AWL=%llu, "
 301                                       "P.ackno=%llu, S.AWH=%llu \n",
 302                                       (unsigned long long)dp->dccps_awl,
 303                            (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
 304                                       (unsigned long long)dp->dccps_awh);
 305                         goto out_invalid_packet;
 306                 }
 307
 308                 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
 309                 dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
 310
 311                 if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 ||
 312                     ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
 313                         ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
 314                         ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
 315                         /* FIXME: send appropriate RESET code */
 316                         goto out_invalid_packet;
 317                 }
 318
 319                 dccp_sync_mss(sk, dp->dccps_pmtu_cookie);
 320
 321                 /*
 322                  *    Step 10: Process REQUEST state (second part)
 323                  *       If S.state == REQUEST,
 324                  *        / * If we get here, P is a valid Response from the
 325                  *            server (see Step 4), and we should move to
 326                  *            PARTOPEN state. PARTOPEN means send an Ack,
 327                  *            don't send Data packets, retransmit Acks
 328                  *            periodically, and always include any Init Cookie
 329                  *            from the Response * /
 330                  *        S.state := PARTOPEN
 331                  *        Set PARTOPEN timer
 332                  *        Continue with S.state == PARTOPEN
 333                  *        / * Step 12 will send the Ack completing the
 334                  *            three-way handshake * /
 335                  */
 336                 dccp_set_state(sk, DCCP_PARTOPEN);
 337
 338                 /* Make sure socket is routed, for correct metrics. */
 339                 inet_sk_rebuild_header(sk);
 340
 341                 if (!sock_flag(sk, SOCK_DEAD)) {
 342                         sk->sk_state_change(sk);
 343                         sk_wake_async(sk, 0, POLL_OUT);
 344                 }
 345
 346                 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
 347                     icsk->icsk_accept_queue.rskq_defer_accept) {
 348                         /* Save one ACK. Data will be ready after
 349                          * several ticks, if write_pending is set.
 350                          *
 351                          * It may be deleted, but with this feature tcpdumps
 352                          * look so _wonderfully_ clever, that I was not able
 353                          * to stand against the temptation 8)     --ANK
 354                          */
 355                         /*
 356                          * OK, in DCCP we can as well do a similar trick, its
 357                          * even in the draft, but there is no need for us to
 358                          * schedule an ack here, as dccp_sendmsg does this for
 359                          * us, also stated in the draft. -acme
 360                          */
 361                         __kfree_skb(skb);
 362                         return 0;
 363                 }
 364                 dccp_send_ack(sk);
 365                 return -1;
 366         }
 367
 368 out_invalid_packet:
 369         return 1; /* dccp_v4_do_rcv will send a reset, but...
 370                      FIXME: the reset code should be
 371                             DCCP_RESET_CODE_PACKET_ERROR */
 372 }
 373
 374 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
 375                                                    struct sk_buff *skb,
 376                                                    const struct dccp_hdr *dh,
 377                                                    const unsigned len)
 378 {
 379         int queued = 0;
 380
 381         switch (dh->dccph_type) {
 382         case DCCP_PKT_RESET:
 383                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
 384                 break;
 385         case DCCP_PKT_DATAACK:
 386         case DCCP_PKT_ACK:
 387                 /*
 388                  * FIXME: we should be reseting the PARTOPEN (DELACK) timer
 389                  * here but only if we haven't used the DELACK timer for
 390                  * something else, like sending a delayed ack for a TIMESTAMP
 391                  * echo, etc, for now were not clearing it, sending an extra
 392                  * ACK when there is nothing else to do in DELACK is not a big
 393                  * deal after all.
 394                  */
 395
 396                 /* Stop the PARTOPEN timer */
 397                 if (sk->sk_state == DCCP_PARTOPEN)
 398                         inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
 399
 400                 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
 401                 dccp_set_state(sk, DCCP_OPEN);
 402
 403                 if (dh->dccph_type == DCCP_PKT_DATAACK) {
 404                         dccp_rcv_established(sk, skb, dh, len);
 405                         queued = 1; /* packet was queued
 406                                        (by dccp_rcv_established) */
 407                 }
 408                 break;
 409         }
 410
 411         return queued;
 412 }
 413
 414 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 415                            struct dccp_hdr *dh, unsigned len)
 416 {
 417         struct dccp_sock *dp = dccp_sk(sk);
 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 (dccp_v4_conn_request(sk, skb) < 0)
 450                                 return 1;
 451
 452                         /* FIXME: do congestion control initialization */
 453                         goto discard;
 454                 }
 455                 if (dh->dccph_type == DCCP_PKT_RESET)
 456                         goto discard;
 457
 458                 /* Caller (dccp_v4_do_rcv) will send Reset(No Connection)*/
 459                 return 1;
 460         }
 461
 462         if (sk->sk_state != DCCP_REQUESTING) {
 463                 if (dccp_check_seqno(sk, skb))
 464                         goto discard;
 465
 466                 /*
 467                  * Step 8: Process options and mark acknowledgeable
 468                  */
 469                 if (dccp_parse_options(sk, skb))
 470                         goto discard;
 471
 472                 if (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
 473                     DCCP_PKT_WITHOUT_ACK_SEQ)
 474                         dccp_event_ack_recv(sk, skb);
 475
 476                 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
 477                 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
 478
 479                 /*
 480                  * FIXME: check ECN to see if we should use
 481                  * DCCP_ACKPKTS_STATE_ECN_MARKED
 482                  */
 483                 if (dp->dccps_options.dccpo_send_ack_vector) {
 484                         if (dccp_ackpkts_add(dp->dccps_hc_rx_ackpkts,
 485                                              DCCP_SKB_CB(skb)->dccpd_seq,
 486                                              DCCP_ACKPKTS_STATE_RECEIVED))
 487                                 goto discard;
 488                         /*
 489                          * FIXME: this activation is probably wrong, have to
 490                          * study more TCP delack machinery and how it fits into
 491                          * DCCP draft, but for now it kinda "works" 8)
 492                          */
 493                         if ((dp->dccps_hc_rx_ackpkts->dccpap_ack_seqno ==
 494                              DCCP_MAX_SEQNO + 1) &&
 495                             !inet_csk_ack_scheduled(sk)) {
 496                                 inet_csk_schedule_ack(sk);
 497                                 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
 498                                                           TCP_DELACK_MIN,
 499                                                           DCCP_RTO_MAX);
 500                         }
 501                 }
 502         }
 503
 504         /*
 505          *  Step 9: Process Reset
 506          *      If P.type == Reset,
 507          *              Tear down connection
 508          *              S.state := TIMEWAIT
 509          *              Set TIMEWAIT timer
 510          *              Drop packet and return
 511         */
 512         if (dh->dccph_type == DCCP_PKT_RESET) {
 513                 /*
 514                  * Queue the equivalent of TCP fin so that dccp_recvmsg
 515                  * exits the loop
 516                  */
 517                 dccp_fin(sk, skb);
 518                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
 519                 return 0;
 520                 /*
 521                  *   Step 7: Check for unexpected packet types
 522                  *      If (S.is_server and P.type == CloseReq)
 523                  *          or (S.is_server and P.type == Response)
 524                  *          or (S.is_client and P.type == Request)
 525                  *          or (S.state == RESPOND and P.type == Data),
 526                  *        Send Sync packet acknowledging P.seqno
 527                  *        Drop packet and return
 528                  */
 529         } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
 530                     (dh->dccph_type == DCCP_PKT_RESPONSE ||
 531                      dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
 532                     (dp->dccps_role == DCCP_ROLE_CLIENT &&
 533                      dh->dccph_type == DCCP_PKT_REQUEST) ||
 534                     (sk->sk_state == DCCP_RESPOND &&
 535                      dh->dccph_type == DCCP_PKT_DATA)) {
 536                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
 537                                DCCP_PKT_SYNC);
 538                 goto discard;
 539         }
 540
 541         switch (sk->sk_state) {
 542         case DCCP_CLOSED:
 543                 return 1;
 544
 545         case DCCP_REQUESTING:
 546                 /* FIXME: do congestion control initialization */
 547
 548                 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
 549                 if (queued >= 0)
 550                         return queued;
 551
 552                 __kfree_skb(skb);
 553                 return 0;
 554
 555         case DCCP_RESPOND:
 556         case DCCP_PARTOPEN:
 557                 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
 558                                                                  dh, len);
 559                 break;
 560         }
 561
 562         if (dh->dccph_type == DCCP_PKT_ACK ||
 563             dh->dccph_type == DCCP_PKT_DATAACK) {
 564                 switch (old_state) {
 565                 case DCCP_PARTOPEN:
 566                         sk->sk_state_change(sk);
 567                         sk_wake_async(sk, 0, POLL_OUT);
 568                         break;
 569                 }
 570         }
 571
 572         if (!queued) {
 573 discard:
 574                 __kfree_skb(skb);
 575         }
 576         return 0;
 577 }