[DCCP]: Simplified conditions due to use of enum:8 states
[linux-2.6.git] / 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/dccp.h>
14 #include <linux/skbuff.h>
15
16 #include <net/sock.h>
17
18 #include "ackvec.h"
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         dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
35         dccp_fin(sk, skb);
36         dccp_set_state(sk, DCCP_CLOSED);
37         sk_wake_async(sk, 1, POLL_HUP);
38 }
39
40 static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
41 {
42         /*
43          *   Step 7: Check for unexpected packet types
44          *      If (S.is_server and P.type == CloseReq)
45          *        Send Sync packet acknowledging P.seqno
46          *        Drop packet and return
47          */
48         if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
49                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
50                 return;
51         }
52
53         if (sk->sk_state != DCCP_CLOSING)
54                 dccp_set_state(sk, DCCP_CLOSING);
55         dccp_send_close(sk, 0);
56 }
57
58 static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
59 {
60         struct dccp_sock *dp = dccp_sk(sk);
61
62         if (dccp_msk(sk)->dccpms_send_ack_vector)
63                 dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
64                                             DCCP_SKB_CB(skb)->dccpd_ack_seq);
65 }
66
67 static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
68 {
69         const struct dccp_hdr *dh = dccp_hdr(skb);
70         struct dccp_sock *dp = dccp_sk(sk);
71         u64 lswl, lawl;
72
73         /*
74          *   Step 5: Prepare sequence numbers for Sync
75          *     If P.type == Sync or P.type == SyncAck,
76          *        If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
77          *           / * P is valid, so update sequence number variables
78          *               accordingly.  After this update, P will pass the tests
79          *               in Step 6.  A SyncAck is generated if necessary in
80          *               Step 15 * /
81          *           Update S.GSR, S.SWL, S.SWH
82          *        Otherwise,
83          *           Drop packet and return
84          */
85         if (dh->dccph_type == DCCP_PKT_SYNC || 
86             dh->dccph_type == DCCP_PKT_SYNCACK) {
87                 if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
88                               dp->dccps_awl, dp->dccps_awh) &&
89                     !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
90                         dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
91                 else
92                         return -1;
93         }
94         
95         /*
96          *   Step 6: Check sequence numbers
97          *      Let LSWL = S.SWL and LAWL = S.AWL
98          *      If P.type == CloseReq or P.type == Close or P.type == Reset,
99          *        LSWL := S.GSR + 1, LAWL := S.GAR
100          *      If LSWL <= P.seqno <= S.SWH
101          *           and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
102          *        Update S.GSR, S.SWL, S.SWH
103          *        If P.type != Sync,
104          *           Update S.GAR
105          *      Otherwise,
106          *        Send Sync packet acknowledging P.seqno
107          *        Drop packet and return
108          */
109         lswl = dp->dccps_swl;
110         lawl = dp->dccps_awl;
111
112         if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
113             dh->dccph_type == DCCP_PKT_CLOSE ||
114             dh->dccph_type == DCCP_PKT_RESET) {
115                 lswl = dp->dccps_gsr;
116                 dccp_inc_seqno(&lswl);
117                 lawl = dp->dccps_gar;
118         }
119
120         if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
121             (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ ||
122              between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
123                        lawl, dp->dccps_awh))) {
124                 dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
125
126                 if (dh->dccph_type != DCCP_PKT_SYNC &&
127                     (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
128                      DCCP_PKT_WITHOUT_ACK_SEQ))
129                         dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
130         } else {
131                 DCCP_WARN("DCCP: Step 6 failed for %s packet, "
132                           "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
133                           "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
134                           "sending SYNC...\n",  dccp_packet_name(dh->dccph_type),
135                           (unsigned long long) lswl,
136                           (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq,
137                           (unsigned long long) dp->dccps_swh,
138                           (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
139                                 DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
140                           (unsigned long long) lawl,
141                           (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq,
142                           (unsigned long long) dp->dccps_awh);
143                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
144                 return -1;
145         }
146
147         return 0;
148 }
149
150 static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
151                                   const struct dccp_hdr *dh, const unsigned len)
152 {
153         struct dccp_sock *dp = dccp_sk(sk);
154
155         switch (dccp_hdr(skb)->dccph_type) {
156         case DCCP_PKT_DATAACK:
157         case DCCP_PKT_DATA:
158                 /*
159                  * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
160                  * option if it is.
161                  */
162                 __skb_pull(skb, dh->dccph_doff * 4);
163                 __skb_queue_tail(&sk->sk_receive_queue, skb);
164                 skb_set_owner_r(skb, sk);
165                 sk->sk_data_ready(sk, 0);
166                 return 0;
167         case DCCP_PKT_ACK:
168                 goto discard;
169         case DCCP_PKT_RESET:
170                 /*
171                  *  Step 9: Process Reset
172                  *      If P.type == Reset,
173                  *              Tear down connection
174                  *              S.state := TIMEWAIT
175                  *              Set TIMEWAIT timer
176                  *              Drop packet and return
177                 */
178                 dccp_fin(sk, skb);
179                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
180                 return 0;
181         case DCCP_PKT_CLOSEREQ:
182                 dccp_rcv_closereq(sk, skb);
183                 goto discard;
184         case DCCP_PKT_CLOSE:
185                 dccp_rcv_close(sk, skb);
186                 return 0;
187         case DCCP_PKT_REQUEST:
188                 /* Step 7 
189                  *   or (S.is_server and P.type == Response)
190                  *   or (S.is_client and P.type == Request)
191                  *   or (S.state >= OPEN and P.type == Request
192                  *      and P.seqno >= S.OSR)
193                  *    or (S.state >= OPEN and P.type == Response
194                  *      and P.seqno >= S.OSR)
195                  *    or (S.state == RESPOND and P.type == Data),
196                  *  Send Sync packet acknowledging P.seqno
197                  *  Drop packet and return
198                  */
199                 if (dp->dccps_role != DCCP_ROLE_LISTEN)
200                         goto send_sync;
201                 goto check_seq;
202         case DCCP_PKT_RESPONSE:
203                 if (dp->dccps_role != DCCP_ROLE_CLIENT)
204                         goto send_sync;
205 check_seq:
206                 if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
207 send_sync:
208                         dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
209                                        DCCP_PKT_SYNC);
210                 }
211                 break;
212         case DCCP_PKT_SYNC:
213                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
214                                DCCP_PKT_SYNCACK);
215                 /*
216                  * From RFC 4340, sec. 5.7
217                  *
218                  * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
219                  * MAY have non-zero-length application data areas, whose
220                  * contents receivers MUST ignore.
221                  */
222                 goto discard;
223         }
224
225         DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
226 discard:
227         __kfree_skb(skb);
228         return 0;
229 }
230
231 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
232                          const struct dccp_hdr *dh, const unsigned len)
233 {
234         struct dccp_sock *dp = dccp_sk(sk);
235
236         if (dccp_check_seqno(sk, skb))
237                 goto discard;
238
239         if (dccp_parse_options(sk, skb))
240                 goto discard;
241
242         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
243                 dccp_event_ack_recv(sk, skb);
244
245         if (dccp_msk(sk)->dccpms_send_ack_vector &&
246             dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
247                             DCCP_SKB_CB(skb)->dccpd_seq,
248                             DCCP_ACKVEC_STATE_RECEIVED))
249                 goto discard;
250
251         ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
252         ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
253
254         return __dccp_rcv_established(sk, skb, dh, len);
255 discard:
256         __kfree_skb(skb);
257         return 0;
258 }
259
260 EXPORT_SYMBOL_GPL(dccp_rcv_established);
261
262 static int dccp_rcv_request_sent_state_process(struct sock *sk,
263                                                struct sk_buff *skb,
264                                                const struct dccp_hdr *dh,
265                                                const unsigned len)
266 {
267         /* 
268          *  Step 4: Prepare sequence numbers in REQUEST
269          *     If S.state == REQUEST,
270          *        If (P.type == Response or P.type == Reset)
271          *              and S.AWL <= P.ackno <= S.AWH,
272          *           / * Set sequence number variables corresponding to the
273          *              other endpoint, so P will pass the tests in Step 6 * /
274          *           Set S.GSR, S.ISR, S.SWL, S.SWH
275          *           / * Response processing continues in Step 10; Reset
276          *              processing continues in Step 9 * /
277         */
278         if (dh->dccph_type == DCCP_PKT_RESPONSE) {
279                 const struct inet_connection_sock *icsk = inet_csk(sk);
280                 struct dccp_sock *dp = dccp_sk(sk);
281
282                 /* Stop the REQUEST timer */
283                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
284                 BUG_TRAP(sk->sk_send_head != NULL);
285                 __kfree_skb(sk->sk_send_head);
286                 sk->sk_send_head = NULL;
287
288                 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
289                                dp->dccps_awl, dp->dccps_awh)) {
290                         dccp_pr_debug("invalid ackno: S.AWL=%llu, "
291                                       "P.ackno=%llu, S.AWH=%llu \n",
292                                       (unsigned long long)dp->dccps_awl,
293                            (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
294                                       (unsigned long long)dp->dccps_awh);
295                         goto out_invalid_packet;
296                 }
297
298                 if (dccp_parse_options(sk, skb))
299                         goto out_invalid_packet;
300
301                 if (dccp_msk(sk)->dccpms_send_ack_vector &&
302                     dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
303                                     DCCP_SKB_CB(skb)->dccpd_seq,
304                                     DCCP_ACKVEC_STATE_RECEIVED))
305                         goto out_invalid_packet; /* FIXME: change error code */
306
307                 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
308                 dccp_update_gsr(sk, dp->dccps_isr);
309                 /*
310                  * SWL and AWL are initially adjusted so that they are not less than
311                  * the initial Sequence Numbers received and sent, respectively:
312                  *      SWL := max(GSR + 1 - floor(W/4), ISR),
313                  *      AWL := max(GSS - W' + 1, ISS).
314                  * These adjustments MUST be applied only at the beginning of the
315                  * connection.
316                  *
317                  * AWL was adjusted in dccp_v4_connect -acme
318                  */
319                 dccp_set_seqno(&dp->dccps_swl,
320                                max48(dp->dccps_swl, dp->dccps_isr));
321
322                 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
323
324                 /*
325                  *    Step 10: Process REQUEST state (second part)
326                  *       If S.state == REQUEST,
327                  *        / * If we get here, P is a valid Response from the
328                  *            server (see Step 4), and we should move to
329                  *            PARTOPEN state. PARTOPEN means send an Ack,
330                  *            don't send Data packets, retransmit Acks
331                  *            periodically, and always include any Init Cookie
332                  *            from the Response * /
333                  *        S.state := PARTOPEN
334                  *        Set PARTOPEN timer
335                  *        Continue with S.state == PARTOPEN
336                  *        / * Step 12 will send the Ack completing the
337                  *            three-way handshake * /
338                  */
339                 dccp_set_state(sk, DCCP_PARTOPEN);
340
341                 /* Make sure socket is routed, for correct metrics. */
342                 icsk->icsk_af_ops->rebuild_header(sk);
343
344                 if (!sock_flag(sk, SOCK_DEAD)) {
345                         sk->sk_state_change(sk);
346                         sk_wake_async(sk, 0, POLL_OUT);
347                 }
348
349                 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
350                     icsk->icsk_accept_queue.rskq_defer_accept) {
351                         /* Save one ACK. Data will be ready after
352                          * several ticks, if write_pending is set.
353                          *
354                          * It may be deleted, but with this feature tcpdumps
355                          * look so _wonderfully_ clever, that I was not able
356                          * to stand against the temptation 8)     --ANK
357                          */
358                         /*
359                          * OK, in DCCP we can as well do a similar trick, its
360                          * even in the draft, but there is no need for us to
361                          * schedule an ack here, as dccp_sendmsg does this for
362                          * us, also stated in the draft. -acme
363                          */
364                         __kfree_skb(skb);
365                         return 0;
366                 } 
367                 dccp_send_ack(sk);
368                 return -1;
369         }
370
371 out_invalid_packet:
372         /* dccp_v4_do_rcv will send a reset */
373         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
374         return 1; 
375 }
376
377 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
378                                                    struct sk_buff *skb,
379                                                    const struct dccp_hdr *dh,
380                                                    const unsigned len)
381 {
382         int queued = 0;
383
384         switch (dh->dccph_type) {
385         case DCCP_PKT_RESET:
386                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
387                 break;
388         case DCCP_PKT_DATA:
389                 if (sk->sk_state == DCCP_RESPOND)
390                         break;
391         case DCCP_PKT_DATAACK:
392         case DCCP_PKT_ACK:
393                 /*
394                  * FIXME: we should be reseting the PARTOPEN (DELACK) timer
395                  * here but only if we haven't used the DELACK timer for
396                  * something else, like sending a delayed ack for a TIMESTAMP
397                  * echo, etc, for now were not clearing it, sending an extra
398                  * ACK when there is nothing else to do in DELACK is not a big
399                  * deal after all.
400                  */
401
402                 /* Stop the PARTOPEN timer */
403                 if (sk->sk_state == DCCP_PARTOPEN)
404                         inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
405
406                 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
407                 dccp_set_state(sk, DCCP_OPEN);
408
409                 if (dh->dccph_type == DCCP_PKT_DATAACK ||
410                     dh->dccph_type == DCCP_PKT_DATA) {
411                         __dccp_rcv_established(sk, skb, dh, len);
412                         queued = 1; /* packet was queued
413                                        (by __dccp_rcv_established) */
414                 }
415                 break;
416         }
417
418         return queued;
419 }
420
421 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
422                            struct dccp_hdr *dh, unsigned len)
423 {
424         struct dccp_sock *dp = dccp_sk(sk);
425         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
426         const int old_state = sk->sk_state;
427         int queued = 0;
428
429         /*
430          *  Step 3: Process LISTEN state
431          *
432          *     If S.state == LISTEN,
433          *       If P.type == Request or P contains a valid Init Cookie option,
434          *            (* Must scan the packet's options to check for Init
435          *               Cookies.  Only Init Cookies are processed here,
436          *               however; other options are processed in Step 8.  This
437          *               scan need only be performed if the endpoint uses Init
438          *               Cookies *)
439          *            (* Generate a new socket and switch to that socket *)
440          *            Set S := new socket for this port pair
441          *            S.state = RESPOND
442          *            Choose S.ISS (initial seqno) or set from Init Cookies
443          *            Initialize S.GAR := S.ISS
444          *            Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
445          *            Cookies Continue with S.state == RESPOND
446          *            (* A Response packet will be generated in Step 11 *)
447          *       Otherwise,
448          *            Generate Reset(No Connection) unless P.type == Reset
449          *            Drop packet and return
450          */
451         if (sk->sk_state == DCCP_LISTEN) {
452                 if (dh->dccph_type == DCCP_PKT_REQUEST) {
453                         if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
454                                                                     skb) < 0)
455                                 return 1;
456
457                         /* FIXME: do congestion control initialization */
458                         goto discard;
459                 }
460                 if (dh->dccph_type == DCCP_PKT_RESET)
461                         goto discard;
462
463                 /* Caller (dccp_v4_do_rcv) will send Reset */
464                 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
465                 return 1;
466         }
467
468         if (sk->sk_state != DCCP_REQUESTING) {
469                 if (dccp_check_seqno(sk, skb))
470                         goto discard;
471
472                 /*
473                  * Step 8: Process options and mark acknowledgeable
474                  */
475                 if (dccp_parse_options(sk, skb))
476                         goto discard;
477
478                 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
479                         dccp_event_ack_recv(sk, skb);
480
481                 if (dccp_msk(sk)->dccpms_send_ack_vector &&
482                     dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
483                                     DCCP_SKB_CB(skb)->dccpd_seq,
484                                     DCCP_ACKVEC_STATE_RECEIVED))
485                         goto discard;
486
487                 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
488                 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
489         }
490
491         /*
492          *  Step 9: Process Reset
493          *      If P.type == Reset,
494          *              Tear down connection
495          *              S.state := TIMEWAIT
496          *              Set TIMEWAIT timer
497          *              Drop packet and return
498         */
499         if (dh->dccph_type == DCCP_PKT_RESET) {
500                 /*
501                  * Queue the equivalent of TCP fin so that dccp_recvmsg
502                  * exits the loop
503                  */
504                 dccp_fin(sk, skb);
505                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
506                 return 0;
507                 /*
508                  *   Step 7: Check for unexpected packet types
509                  *      If (S.is_server and P.type == CloseReq)
510                  *          or (S.is_server and P.type == Response)
511                  *          or (S.is_client and P.type == Request)
512                  *          or (S.state == RESPOND and P.type == Data),
513                  *        Send Sync packet acknowledging P.seqno
514                  *        Drop packet and return
515                  */
516         } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
517                     (dh->dccph_type == DCCP_PKT_RESPONSE ||
518                      dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
519                     (dp->dccps_role == DCCP_ROLE_CLIENT &&
520                      dh->dccph_type == DCCP_PKT_REQUEST) ||
521                     (sk->sk_state == DCCP_RESPOND &&
522                      dh->dccph_type == DCCP_PKT_DATA)) {
523                 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
524                 goto discard;
525         } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
526                 dccp_rcv_closereq(sk, skb);
527                 goto discard;
528         } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
529                 dccp_rcv_close(sk, skb);
530                 return 0;
531         }
532
533         if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
534                 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
535                 goto discard;
536         }
537
538         switch (sk->sk_state) {
539         case DCCP_CLOSED:
540                 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
541                 return 1;
542
543         case DCCP_REQUESTING:
544                 /* FIXME: do congestion control initialization */
545
546                 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
547                 if (queued >= 0)
548                         return queued;
549
550                 __kfree_skb(skb);
551                 return 0;
552
553         case DCCP_RESPOND:
554         case DCCP_PARTOPEN:
555                 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
556                                                                  dh, len);
557                 break;
558         }
559
560         if (dh->dccph_type == DCCP_PKT_ACK ||
561             dh->dccph_type == DCCP_PKT_DATAACK) {
562                 switch (old_state) {
563                 case DCCP_PARTOPEN:
564                         sk->sk_state_change(sk);
565                         sk_wake_async(sk, 0, POLL_OUT);
566                         break;
567                 }
568         }
569
570         if (!queued) { 
571 discard:
572                 __kfree_skb(skb);
573         }
574         return 0;
575 }
576
577 EXPORT_SYMBOL_GPL(dccp_rcv_state_process);