Merge master.kernel.org:/pub/scm/linux/kernel/git/sfrench/cifs-2.6-stable
[linux-2.6] / 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 "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 static inline int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
155                                          const struct dccp_hdr *dh,
156                                          const unsigned len)
157 {
158         struct dccp_sock *dp = dccp_sk(sk);
159
160         switch (dccp_hdr(skb)->dccph_type) {
161         case DCCP_PKT_DATAACK:
162         case DCCP_PKT_DATA:
163                 /*
164                  * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
165                  * option if it is.
166                  */
167                 __skb_pull(skb, dh->dccph_doff * 4);
168                 __skb_queue_tail(&sk->sk_receive_queue, skb);
169                 skb_set_owner_r(skb, sk);
170                 sk->sk_data_ready(sk, 0);
171                 return 0;
172         case DCCP_PKT_ACK:
173                 goto discard;
174         case DCCP_PKT_RESET:
175                 /*
176                  *  Step 9: Process Reset
177                  *      If P.type == Reset,
178                  *              Tear down connection
179                  *              S.state := TIMEWAIT
180                  *              Set TIMEWAIT timer
181                  *              Drop packet and return
182                 */
183                 dccp_fin(sk, skb);
184                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
185                 return 0;
186         case DCCP_PKT_CLOSEREQ:
187                 dccp_rcv_closereq(sk, skb);
188                 goto discard;
189         case DCCP_PKT_CLOSE:
190                 dccp_rcv_close(sk, skb);
191                 return 0;
192         case DCCP_PKT_REQUEST:
193                 /* Step 7 
194                  *   or (S.is_server and P.type == Response)
195                  *   or (S.is_client and P.type == Request)
196                  *   or (S.state >= OPEN and P.type == Request
197                  *      and P.seqno >= S.OSR)
198                  *    or (S.state >= OPEN and P.type == Response
199                  *      and P.seqno >= S.OSR)
200                  *    or (S.state == RESPOND and P.type == Data),
201                  *  Send Sync packet acknowledging P.seqno
202                  *  Drop packet and return
203                  */
204                 if (dp->dccps_role != DCCP_ROLE_LISTEN)
205                         goto send_sync;
206                 goto check_seq;
207         case DCCP_PKT_RESPONSE:
208                 if (dp->dccps_role != DCCP_ROLE_CLIENT)
209                         goto send_sync;
210 check_seq:
211                 if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
212 send_sync:
213                         dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
214                                        DCCP_PKT_SYNC);
215                 }
216                 break;
217         case DCCP_PKT_SYNC:
218                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
219                                DCCP_PKT_SYNCACK);
220                 /*
221                  * From the draft:
222                  *
223                  * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
224                  * MAY have non-zero-length application data areas, whose
225                  * contents * receivers MUST ignore.
226                  */
227                 goto discard;
228         }
229
230         DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
231 discard:
232         __kfree_skb(skb);
233         return 0;
234 }
235
236 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
237                          const struct dccp_hdr *dh, const unsigned len)
238 {
239         struct dccp_sock *dp = dccp_sk(sk);
240
241         if (dccp_check_seqno(sk, skb))
242                 goto discard;
243
244         if (dccp_parse_options(sk, skb))
245                 goto discard;
246
247         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
248                 dccp_event_ack_recv(sk, skb);
249
250         if (dp->dccps_options.dccpo_send_ack_vector &&
251             dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
252                             DCCP_SKB_CB(skb)->dccpd_seq,
253                             DCCP_ACKVEC_STATE_RECEIVED))
254                 goto discard;
255
256         ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
257         ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
258
259         return __dccp_rcv_established(sk, skb, dh, len);
260 discard:
261         __kfree_skb(skb);
262         return 0;
263 }
264
265 EXPORT_SYMBOL_GPL(dccp_rcv_established);
266
267 static int dccp_rcv_request_sent_state_process(struct sock *sk,
268                                                struct sk_buff *skb,
269                                                const struct dccp_hdr *dh,
270                                                const unsigned len)
271 {
272         /* 
273          *  Step 4: Prepare sequence numbers in REQUEST
274          *     If S.state == REQUEST,
275          *        If (P.type == Response or P.type == Reset)
276          *              and S.AWL <= P.ackno <= S.AWH,
277          *           / * Set sequence number variables corresponding to the
278          *              other endpoint, so P will pass the tests in Step 6 * /
279          *           Set S.GSR, S.ISR, S.SWL, S.SWH
280          *           / * Response processing continues in Step 10; Reset
281          *              processing continues in Step 9 * /
282         */
283         if (dh->dccph_type == DCCP_PKT_RESPONSE) {
284                 const struct inet_connection_sock *icsk = inet_csk(sk);
285                 struct dccp_sock *dp = dccp_sk(sk);
286
287                 /* Stop the REQUEST timer */
288                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
289                 BUG_TRAP(sk->sk_send_head != NULL);
290                 __kfree_skb(sk->sk_send_head);
291                 sk->sk_send_head = NULL;
292
293                 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
294                                dp->dccps_awl, dp->dccps_awh)) {
295                         dccp_pr_debug("invalid ackno: S.AWL=%llu, "
296                                       "P.ackno=%llu, S.AWH=%llu \n",
297                                       (unsigned long long)dp->dccps_awl,
298                            (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
299                                       (unsigned long long)dp->dccps_awh);
300                         goto out_invalid_packet;
301                 }
302
303                 if (dp->dccps_options.dccpo_send_ack_vector &&
304                     dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
305                                     DCCP_SKB_CB(skb)->dccpd_seq,
306                                     DCCP_ACKVEC_STATE_RECEIVED))
307                         goto out_invalid_packet; /* FIXME: change error code */
308
309                 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
310                 dccp_update_gsr(sk, dp->dccps_isr);
311                 /*
312                  * SWL and AWL are initially adjusted so that they are not less than
313                  * the initial Sequence Numbers received and sent, respectively:
314                  *      SWL := max(GSR + 1 - floor(W/4), ISR),
315                  *      AWL := max(GSS - W' + 1, ISS).
316                  * These adjustments MUST be applied only at the beginning of the
317                  * connection.
318                  *
319                  * AWL was adjusted in dccp_v4_connect -acme
320                  */
321                 dccp_set_seqno(&dp->dccps_swl,
322                                max48(dp->dccps_swl, dp->dccps_isr));
323
324                 if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 ||
325                     ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
326                         ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
327                         ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
328                         /* FIXME: send appropriate RESET code */
329                         goto out_invalid_packet;
330                 }
331
332                 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
333
334                 /*
335                  *    Step 10: Process REQUEST state (second part)
336                  *       If S.state == REQUEST,
337                  *        / * If we get here, P is a valid Response from the
338                  *            server (see Step 4), and we should move to
339                  *            PARTOPEN state. PARTOPEN means send an Ack,
340                  *            don't send Data packets, retransmit Acks
341                  *            periodically, and always include any Init Cookie
342                  *            from the Response * /
343                  *        S.state := PARTOPEN
344                  *        Set PARTOPEN timer
345                  *        Continue with S.state == PARTOPEN
346                  *        / * Step 12 will send the Ack completing the
347                  *            three-way handshake * /
348                  */
349                 dccp_set_state(sk, DCCP_PARTOPEN);
350
351                 /* Make sure socket is routed, for correct metrics. */
352                 icsk->icsk_af_ops->rebuild_header(sk);
353
354                 if (!sock_flag(sk, SOCK_DEAD)) {
355                         sk->sk_state_change(sk);
356                         sk_wake_async(sk, 0, POLL_OUT);
357                 }
358
359                 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
360                     icsk->icsk_accept_queue.rskq_defer_accept) {
361                         /* Save one ACK. Data will be ready after
362                          * several ticks, if write_pending is set.
363                          *
364                          * It may be deleted, but with this feature tcpdumps
365                          * look so _wonderfully_ clever, that I was not able
366                          * to stand against the temptation 8)     --ANK
367                          */
368                         /*
369                          * OK, in DCCP we can as well do a similar trick, its
370                          * even in the draft, but there is no need for us to
371                          * schedule an ack here, as dccp_sendmsg does this for
372                          * us, also stated in the draft. -acme
373                          */
374                         __kfree_skb(skb);
375                         return 0;
376                 } 
377                 dccp_send_ack(sk);
378                 return -1;
379         }
380
381 out_invalid_packet:
382         /* dccp_v4_do_rcv will send a reset */
383         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
384         return 1; 
385 }
386
387 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
388                                                    struct sk_buff *skb,
389                                                    const struct dccp_hdr *dh,
390                                                    const unsigned len)
391 {
392         int queued = 0;
393
394         switch (dh->dccph_type) {
395         case DCCP_PKT_RESET:
396                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
397                 break;
398         case DCCP_PKT_DATA:
399                 if (sk->sk_state == DCCP_RESPOND)
400                         break;
401         case DCCP_PKT_DATAACK:
402         case DCCP_PKT_ACK:
403                 /*
404                  * FIXME: we should be reseting the PARTOPEN (DELACK) timer
405                  * here but only if we haven't used the DELACK timer for
406                  * something else, like sending a delayed ack for a TIMESTAMP
407                  * echo, etc, for now were not clearing it, sending an extra
408                  * ACK when there is nothing else to do in DELACK is not a big
409                  * deal after all.
410                  */
411
412                 /* Stop the PARTOPEN timer */
413                 if (sk->sk_state == DCCP_PARTOPEN)
414                         inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
415
416                 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
417                 dccp_set_state(sk, DCCP_OPEN);
418
419                 if (dh->dccph_type == DCCP_PKT_DATAACK ||
420                     dh->dccph_type == DCCP_PKT_DATA) {
421                         __dccp_rcv_established(sk, skb, dh, len);
422                         queued = 1; /* packet was queued
423                                        (by __dccp_rcv_established) */
424                 }
425                 break;
426         }
427
428         return queued;
429 }
430
431 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
432                            struct dccp_hdr *dh, unsigned len)
433 {
434         struct dccp_sock *dp = dccp_sk(sk);
435         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
436         const int old_state = sk->sk_state;
437         int queued = 0;
438
439         /*
440          *  Step 3: Process LISTEN state
441          *      (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
442          *
443          *     If S.state == LISTEN,
444          *        If P.type == Request or P contains a valid Init Cookie
445          *              option,
446          *           * Must scan the packet's options to check for an Init
447          *              Cookie.  Only the Init Cookie is processed here,
448          *              however; other options are processed in Step 8.  This
449          *              scan need only be performed if the endpoint uses Init
450          *              Cookies *
451          *           * Generate a new socket and switch to that socket *
452          *           Set S := new socket for this port pair
453          *           S.state = RESPOND
454          *           Choose S.ISS (initial seqno) or set from Init Cookie
455          *           Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
456          *           Continue with S.state == RESPOND
457          *           * A Response packet will be generated in Step 11 *
458          *        Otherwise,
459          *           Generate Reset(No Connection) unless P.type == Reset
460          *           Drop packet and return
461          *
462          * NOTE: the check for the packet types is done in
463          *       dccp_rcv_state_process
464          */
465         if (sk->sk_state == DCCP_LISTEN) {
466                 if (dh->dccph_type == DCCP_PKT_REQUEST) {
467                         if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
468                                                                     skb) < 0)
469                                 return 1;
470
471                         /* FIXME: do congestion control initialization */
472                         goto discard;
473                 }
474                 if (dh->dccph_type == DCCP_PKT_RESET)
475                         goto discard;
476
477                 /* Caller (dccp_v4_do_rcv) will send Reset */
478                 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
479                 return 1;
480         }
481
482         if (sk->sk_state != DCCP_REQUESTING) {
483                 if (dccp_check_seqno(sk, skb))
484                         goto discard;
485
486                 /*
487                  * Step 8: Process options and mark acknowledgeable
488                  */
489                 if (dccp_parse_options(sk, skb))
490                         goto discard;
491
492                 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
493                         dccp_event_ack_recv(sk, skb);
494
495                 if (dp->dccps_options.dccpo_send_ack_vector &&
496                     dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
497                                     DCCP_SKB_CB(skb)->dccpd_seq,
498                                     DCCP_ACKVEC_STATE_RECEIVED))
499                         goto discard;
500
501                 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
502                 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
503         }
504
505         /*
506          *  Step 9: Process Reset
507          *      If P.type == Reset,
508          *              Tear down connection
509          *              S.state := TIMEWAIT
510          *              Set TIMEWAIT timer
511          *              Drop packet and return
512         */
513         if (dh->dccph_type == DCCP_PKT_RESET) {
514                 /*
515                  * Queue the equivalent of TCP fin so that dccp_recvmsg
516                  * exits the loop
517                  */
518                 dccp_fin(sk, skb);
519                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
520                 return 0;
521                 /*
522                  *   Step 7: Check for unexpected packet types
523                  *      If (S.is_server and P.type == CloseReq)
524                  *          or (S.is_server and P.type == Response)
525                  *          or (S.is_client and P.type == Request)
526                  *          or (S.state == RESPOND and P.type == Data),
527                  *        Send Sync packet acknowledging P.seqno
528                  *        Drop packet and return
529                  */
530         } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
531                     (dh->dccph_type == DCCP_PKT_RESPONSE ||
532                      dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
533                     (dp->dccps_role == DCCP_ROLE_CLIENT &&
534                      dh->dccph_type == DCCP_PKT_REQUEST) ||
535                     (sk->sk_state == DCCP_RESPOND &&
536                      dh->dccph_type == DCCP_PKT_DATA)) {
537                 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
538                 goto discard;
539         } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
540                 dccp_rcv_closereq(sk, skb);
541                 goto discard;
542         } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
543                 dccp_rcv_close(sk, skb);
544                 return 0;
545         }
546
547         if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
548                 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
549                 goto discard;
550         }
551
552         switch (sk->sk_state) {
553         case DCCP_CLOSED:
554                 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
555                 return 1;
556
557         case DCCP_REQUESTING:
558                 /* FIXME: do congestion control initialization */
559
560                 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
561                 if (queued >= 0)
562                         return queued;
563
564                 __kfree_skb(skb);
565                 return 0;
566
567         case DCCP_RESPOND:
568         case DCCP_PARTOPEN:
569                 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
570                                                                  dh, len);
571                 break;
572         }
573
574         if (dh->dccph_type == DCCP_PKT_ACK ||
575             dh->dccph_type == DCCP_PKT_DATAACK) {
576                 switch (old_state) {
577                 case DCCP_PARTOPEN:
578                         sk->sk_state_change(sk);
579                         sk_wake_async(sk, 0, POLL_OUT);
580                         break;
581                 }
582         }
583
584         if (!queued) { 
585 discard:
586                 __kfree_skb(skb);
587         }
588         return 0;
589 }
590
591 EXPORT_SYMBOL_GPL(dccp_rcv_state_process);