Remove obsolete #include <linux/config.h>
[linux-3.10.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                 LIMIT_NETDEBUG(KERN_WARNING "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",
135                                dccp_packet_name(dh->dccph_type),
136                                (unsigned long long) lswl,
137                                (unsigned long long)
138                                DCCP_SKB_CB(skb)->dccpd_seq,
139                                (unsigned long long) dp->dccps_swh,
140                                (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
141                                 DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
142                                (unsigned long long) lawl,
143                                (unsigned long long)
144                                DCCP_SKB_CB(skb)->dccpd_ack_seq,
145                                (unsigned long long) dp->dccps_awh);
146                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
147                 return -1;
148         }
149
150         return 0;
151 }
152
153 static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
154                                   const struct dccp_hdr *dh, const unsigned len)
155 {
156         struct dccp_sock *dp = dccp_sk(sk);
157
158         switch (dccp_hdr(skb)->dccph_type) {
159         case DCCP_PKT_DATAACK:
160         case DCCP_PKT_DATA:
161                 /*
162                  * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
163                  * option if it is.
164                  */
165                 __skb_pull(skb, dh->dccph_doff * 4);
166                 __skb_queue_tail(&sk->sk_receive_queue, skb);
167                 skb_set_owner_r(skb, sk);
168                 sk->sk_data_ready(sk, 0);
169                 return 0;
170         case DCCP_PKT_ACK:
171                 goto discard;
172         case DCCP_PKT_RESET:
173                 /*
174                  *  Step 9: Process Reset
175                  *      If P.type == Reset,
176                  *              Tear down connection
177                  *              S.state := TIMEWAIT
178                  *              Set TIMEWAIT timer
179                  *              Drop packet and return
180                 */
181                 dccp_fin(sk, skb);
182                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
183                 return 0;
184         case DCCP_PKT_CLOSEREQ:
185                 dccp_rcv_closereq(sk, skb);
186                 goto discard;
187         case DCCP_PKT_CLOSE:
188                 dccp_rcv_close(sk, skb);
189                 return 0;
190         case DCCP_PKT_REQUEST:
191                 /* Step 7 
192                  *   or (S.is_server and P.type == Response)
193                  *   or (S.is_client and P.type == Request)
194                  *   or (S.state >= OPEN and P.type == Request
195                  *      and P.seqno >= S.OSR)
196                  *    or (S.state >= OPEN and P.type == Response
197                  *      and P.seqno >= S.OSR)
198                  *    or (S.state == RESPOND and P.type == Data),
199                  *  Send Sync packet acknowledging P.seqno
200                  *  Drop packet and return
201                  */
202                 if (dp->dccps_role != DCCP_ROLE_LISTEN)
203                         goto send_sync;
204                 goto check_seq;
205         case DCCP_PKT_RESPONSE:
206                 if (dp->dccps_role != DCCP_ROLE_CLIENT)
207                         goto send_sync;
208 check_seq:
209                 if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
210 send_sync:
211                         dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
212                                        DCCP_PKT_SYNC);
213                 }
214                 break;
215         case DCCP_PKT_SYNC:
216                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
217                                DCCP_PKT_SYNCACK);
218                 /*
219                  * From the draft:
220                  *
221                  * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
222                  * MAY have non-zero-length application data areas, whose
223                  * contents * receivers MUST ignore.
224                  */
225                 goto discard;
226         }
227
228         DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
229 discard:
230         __kfree_skb(skb);
231         return 0;
232 }
233
234 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
235                          const struct dccp_hdr *dh, const unsigned len)
236 {
237         struct dccp_sock *dp = dccp_sk(sk);
238
239         if (dccp_check_seqno(sk, skb))
240                 goto discard;
241
242         if (dccp_parse_options(sk, skb))
243                 goto discard;
244
245         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
246                 dccp_event_ack_recv(sk, skb);
247
248         if (dccp_msk(sk)->dccpms_send_ack_vector &&
249             dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
250                             DCCP_SKB_CB(skb)->dccpd_seq,
251                             DCCP_ACKVEC_STATE_RECEIVED))
252                 goto discard;
253
254         ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
255         ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
256
257         return __dccp_rcv_established(sk, skb, dh, len);
258 discard:
259         __kfree_skb(skb);
260         return 0;
261 }
262
263 EXPORT_SYMBOL_GPL(dccp_rcv_established);
264
265 static int dccp_rcv_request_sent_state_process(struct sock *sk,
266                                                struct sk_buff *skb,
267                                                const struct dccp_hdr *dh,
268                                                const unsigned len)
269 {
270         /* 
271          *  Step 4: Prepare sequence numbers in REQUEST
272          *     If S.state == REQUEST,
273          *        If (P.type == Response or P.type == Reset)
274          *              and S.AWL <= P.ackno <= S.AWH,
275          *           / * Set sequence number variables corresponding to the
276          *              other endpoint, so P will pass the tests in Step 6 * /
277          *           Set S.GSR, S.ISR, S.SWL, S.SWH
278          *           / * Response processing continues in Step 10; Reset
279          *              processing continues in Step 9 * /
280         */
281         if (dh->dccph_type == DCCP_PKT_RESPONSE) {
282                 const struct inet_connection_sock *icsk = inet_csk(sk);
283                 struct dccp_sock *dp = dccp_sk(sk);
284
285                 /* Stop the REQUEST timer */
286                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
287                 BUG_TRAP(sk->sk_send_head != NULL);
288                 __kfree_skb(sk->sk_send_head);
289                 sk->sk_send_head = NULL;
290
291                 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
292                                dp->dccps_awl, dp->dccps_awh)) {
293                         dccp_pr_debug("invalid ackno: S.AWL=%llu, "
294                                       "P.ackno=%llu, S.AWH=%llu \n",
295                                       (unsigned long long)dp->dccps_awl,
296                            (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
297                                       (unsigned long long)dp->dccps_awh);
298                         goto out_invalid_packet;
299                 }
300
301                 if (dccp_parse_options(sk, skb))
302                         goto out_invalid_packet;
303
304                 if (dccp_msk(sk)->dccpms_send_ack_vector &&
305                     dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
306                                     DCCP_SKB_CB(skb)->dccpd_seq,
307                                     DCCP_ACKVEC_STATE_RECEIVED))
308                         goto out_invalid_packet; /* FIXME: change error code */
309
310                 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
311                 dccp_update_gsr(sk, dp->dccps_isr);
312                 /*
313                  * SWL and AWL are initially adjusted so that they are not less than
314                  * the initial Sequence Numbers received and sent, respectively:
315                  *      SWL := max(GSR + 1 - floor(W/4), ISR),
316                  *      AWL := max(GSS - W' + 1, ISS).
317                  * These adjustments MUST be applied only at the beginning of the
318                  * connection.
319                  *
320                  * AWL was adjusted in dccp_v4_connect -acme
321                  */
322                 dccp_set_seqno(&dp->dccps_swl,
323                                max48(dp->dccps_swl, dp->dccps_isr));
324
325                 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
326
327                 /*
328                  *    Step 10: Process REQUEST state (second part)
329                  *       If S.state == REQUEST,
330                  *        / * If we get here, P is a valid Response from the
331                  *            server (see Step 4), and we should move to
332                  *            PARTOPEN state. PARTOPEN means send an Ack,
333                  *            don't send Data packets, retransmit Acks
334                  *            periodically, and always include any Init Cookie
335                  *            from the Response * /
336                  *        S.state := PARTOPEN
337                  *        Set PARTOPEN timer
338                  *        Continue with S.state == PARTOPEN
339                  *        / * Step 12 will send the Ack completing the
340                  *            three-way handshake * /
341                  */
342                 dccp_set_state(sk, DCCP_PARTOPEN);
343
344                 /* Make sure socket is routed, for correct metrics. */
345                 icsk->icsk_af_ops->rebuild_header(sk);
346
347                 if (!sock_flag(sk, SOCK_DEAD)) {
348                         sk->sk_state_change(sk);
349                         sk_wake_async(sk, 0, POLL_OUT);
350                 }
351
352                 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
353                     icsk->icsk_accept_queue.rskq_defer_accept) {
354                         /* Save one ACK. Data will be ready after
355                          * several ticks, if write_pending is set.
356                          *
357                          * It may be deleted, but with this feature tcpdumps
358                          * look so _wonderfully_ clever, that I was not able
359                          * to stand against the temptation 8)     --ANK
360                          */
361                         /*
362                          * OK, in DCCP we can as well do a similar trick, its
363                          * even in the draft, but there is no need for us to
364                          * schedule an ack here, as dccp_sendmsg does this for
365                          * us, also stated in the draft. -acme
366                          */
367                         __kfree_skb(skb);
368                         return 0;
369                 } 
370                 dccp_send_ack(sk);
371                 return -1;
372         }
373
374 out_invalid_packet:
375         /* dccp_v4_do_rcv will send a reset */
376         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
377         return 1; 
378 }
379
380 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
381                                                    struct sk_buff *skb,
382                                                    const struct dccp_hdr *dh,
383                                                    const unsigned len)
384 {
385         int queued = 0;
386
387         switch (dh->dccph_type) {
388         case DCCP_PKT_RESET:
389                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
390                 break;
391         case DCCP_PKT_DATA:
392                 if (sk->sk_state == DCCP_RESPOND)
393                         break;
394         case DCCP_PKT_DATAACK:
395         case DCCP_PKT_ACK:
396                 /*
397                  * FIXME: we should be reseting the PARTOPEN (DELACK) timer
398                  * here but only if we haven't used the DELACK timer for
399                  * something else, like sending a delayed ack for a TIMESTAMP
400                  * echo, etc, for now were not clearing it, sending an extra
401                  * ACK when there is nothing else to do in DELACK is not a big
402                  * deal after all.
403                  */
404
405                 /* Stop the PARTOPEN timer */
406                 if (sk->sk_state == DCCP_PARTOPEN)
407                         inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
408
409                 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
410                 dccp_set_state(sk, DCCP_OPEN);
411
412                 if (dh->dccph_type == DCCP_PKT_DATAACK ||
413                     dh->dccph_type == DCCP_PKT_DATA) {
414                         __dccp_rcv_established(sk, skb, dh, len);
415                         queued = 1; /* packet was queued
416                                        (by __dccp_rcv_established) */
417                 }
418                 break;
419         }
420
421         return queued;
422 }
423
424 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
425                            struct dccp_hdr *dh, unsigned len)
426 {
427         struct dccp_sock *dp = dccp_sk(sk);
428         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
429         const int old_state = sk->sk_state;
430         int queued = 0;
431
432         /*
433          *  Step 3: Process LISTEN state
434          *      (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
435          *
436          *     If S.state == LISTEN,
437          *        If P.type == Request or P contains a valid Init Cookie
438          *              option,
439          *           * Must scan the packet's options to check for an Init
440          *              Cookie.  Only the Init Cookie is processed here,
441          *              however; other options are processed in Step 8.  This
442          *              scan need only be performed if the endpoint uses Init
443          *              Cookies *
444          *           * Generate a new socket and switch to that socket *
445          *           Set S := new socket for this port pair
446          *           S.state = RESPOND
447          *           Choose S.ISS (initial seqno) or set from Init Cookie
448          *           Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
449          *           Continue with S.state == RESPOND
450          *           * A Response packet will be generated in Step 11 *
451          *        Otherwise,
452          *           Generate Reset(No Connection) unless P.type == Reset
453          *           Drop packet and return
454          *
455          * NOTE: the check for the packet types is done in
456          *       dccp_rcv_state_process
457          */
458         if (sk->sk_state == DCCP_LISTEN) {
459                 if (dh->dccph_type == DCCP_PKT_REQUEST) {
460                         if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
461                                                                     skb) < 0)
462                                 return 1;
463
464                         /* FIXME: do congestion control initialization */
465                         goto discard;
466                 }
467                 if (dh->dccph_type == DCCP_PKT_RESET)
468                         goto discard;
469
470                 /* Caller (dccp_v4_do_rcv) will send Reset */
471                 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
472                 return 1;
473         }
474
475         if (sk->sk_state != DCCP_REQUESTING) {
476                 if (dccp_check_seqno(sk, skb))
477                         goto discard;
478
479                 /*
480                  * Step 8: Process options and mark acknowledgeable
481                  */
482                 if (dccp_parse_options(sk, skb))
483                         goto discard;
484
485                 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
486                         dccp_event_ack_recv(sk, skb);
487
488                 if (dccp_msk(sk)->dccpms_send_ack_vector &&
489                     dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
490                                     DCCP_SKB_CB(skb)->dccpd_seq,
491                                     DCCP_ACKVEC_STATE_RECEIVED))
492                         goto discard;
493
494                 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
495                 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
496         }
497
498         /*
499          *  Step 9: Process Reset
500          *      If P.type == Reset,
501          *              Tear down connection
502          *              S.state := TIMEWAIT
503          *              Set TIMEWAIT timer
504          *              Drop packet and return
505         */
506         if (dh->dccph_type == DCCP_PKT_RESET) {
507                 /*
508                  * Queue the equivalent of TCP fin so that dccp_recvmsg
509                  * exits the loop
510                  */
511                 dccp_fin(sk, skb);
512                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
513                 return 0;
514                 /*
515                  *   Step 7: Check for unexpected packet types
516                  *      If (S.is_server and P.type == CloseReq)
517                  *          or (S.is_server and P.type == Response)
518                  *          or (S.is_client and P.type == Request)
519                  *          or (S.state == RESPOND and P.type == Data),
520                  *        Send Sync packet acknowledging P.seqno
521                  *        Drop packet and return
522                  */
523         } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
524                     (dh->dccph_type == DCCP_PKT_RESPONSE ||
525                      dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
526                     (dp->dccps_role == DCCP_ROLE_CLIENT &&
527                      dh->dccph_type == DCCP_PKT_REQUEST) ||
528                     (sk->sk_state == DCCP_RESPOND &&
529                      dh->dccph_type == DCCP_PKT_DATA)) {
530                 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
531                 goto discard;
532         } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
533                 dccp_rcv_closereq(sk, skb);
534                 goto discard;
535         } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
536                 dccp_rcv_close(sk, skb);
537                 return 0;
538         }
539
540         if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
541                 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
542                 goto discard;
543         }
544
545         switch (sk->sk_state) {
546         case DCCP_CLOSED:
547                 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
548                 return 1;
549
550         case DCCP_REQUESTING:
551                 /* FIXME: do congestion control initialization */
552
553                 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
554                 if (queued >= 0)
555                         return queued;
556
557                 __kfree_skb(skb);
558                 return 0;
559
560         case DCCP_RESPOND:
561         case DCCP_PARTOPEN:
562                 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
563                                                                  dh, len);
564                 break;
565         }
566
567         if (dh->dccph_type == DCCP_PKT_ACK ||
568             dh->dccph_type == DCCP_PKT_DATAACK) {
569                 switch (old_state) {
570                 case DCCP_PARTOPEN:
571                         sk->sk_state_change(sk);
572                         sk_wake_async(sk, 0, POLL_OUT);
573                         break;
574                 }
575         }
576
577         if (!queued) { 
578 discard:
579                 __kfree_skb(skb);
580         }
581         return 0;
582 }
583
584 EXPORT_SYMBOL_GPL(dccp_rcv_state_process);