[PATCH] Fix CONFIG_ACPI_BLACKLIST_YEAR
[sfrench/cifs-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/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         dccp_v4_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         dccp_set_state(sk, DCCP_CLOSING);
54         dccp_send_close(sk, 0);
55 }
56
57 static inline void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
58 {
59         struct dccp_sock *dp = dccp_sk(sk);
60
61         if (dp->dccps_options.dccpo_send_ack_vector)
62                 dccp_ackpkts_check_rcv_ackno(dp->dccps_hc_rx_ackpkts, sk,
63                                              DCCP_SKB_CB(skb)->dccpd_ack_seq);
64 }
65
66 static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
67 {
68         const struct dccp_hdr *dh = dccp_hdr(skb);
69         struct dccp_sock *dp = dccp_sk(sk);
70         u64 lswl, lawl;
71
72         /*
73          *   Step 5: Prepare sequence numbers for Sync
74          *     If P.type == Sync or P.type == SyncAck,
75          *        If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
76          *           / * P is valid, so update sequence number variables
77          *               accordingly.  After this update, P will pass the tests
78          *               in Step 6.  A SyncAck is generated if necessary in
79          *               Step 15 * /
80          *           Update S.GSR, S.SWL, S.SWH
81          *        Otherwise,
82          *           Drop packet and return
83          */
84         if (dh->dccph_type == DCCP_PKT_SYNC || 
85             dh->dccph_type == DCCP_PKT_SYNCACK) {
86                 if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
87                               dp->dccps_awl, dp->dccps_awh) &&
88                     !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
89                         dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
90                 else
91                         return -1;
92         }
93         
94         /*
95          *   Step 6: Check sequence numbers
96          *      Let LSWL = S.SWL and LAWL = S.AWL
97          *      If P.type == CloseReq or P.type == Close or P.type == Reset,
98          *        LSWL := S.GSR + 1, LAWL := S.GAR
99          *      If LSWL <= P.seqno <= S.SWH
100          *           and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
101          *        Update S.GSR, S.SWL, S.SWH
102          *        If P.type != Sync,
103          *           Update S.GAR
104          *      Otherwise,
105          *        Send Sync packet acknowledging P.seqno
106          *        Drop packet and return
107          */
108         lswl = dp->dccps_swl;
109         lawl = dp->dccps_awl;
110
111         if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
112             dh->dccph_type == DCCP_PKT_CLOSE ||
113             dh->dccph_type == DCCP_PKT_RESET) {
114                 lswl = dp->dccps_gsr;
115                 dccp_inc_seqno(&lswl);
116                 lawl = dp->dccps_gar;
117         }
118
119         if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
120             (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ ||
121              between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
122                        lawl, dp->dccps_awh))) {
123                 dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
124
125                 if (dh->dccph_type != DCCP_PKT_SYNC &&
126                     (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
127                      DCCP_PKT_WITHOUT_ACK_SEQ))
128                         dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
129         } else {
130                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: Step 6 failed for %s packet, "
131                                             "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
132                                             "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
133                                             "sending SYNC...\n",
134                                dccp_packet_name(dh->dccph_type),
135                                (unsigned long long) lswl,
136                                (unsigned long long)
137                                DCCP_SKB_CB(skb)->dccpd_seq,
138                                (unsigned long long) dp->dccps_swh,
139                                (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
140                                 DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
141                                (unsigned long long) lawl,
142                                (unsigned long long)
143                                DCCP_SKB_CB(skb)->dccpd_ack_seq,
144                                (unsigned long long) dp->dccps_awh);
145                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
146                 return -1;
147         }
148
149         return 0;
150 }
151
152 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
153                          const struct dccp_hdr *dh, const unsigned len)
154 {
155         struct dccp_sock *dp = dccp_sk(sk);
156
157         if (dccp_check_seqno(sk, skb))
158                 goto discard;
159
160         if (dccp_parse_options(sk, skb))
161                 goto discard;
162
163         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
164                 dccp_event_ack_recv(sk, skb);
165
166         /*
167          * FIXME: check ECN to see if we should use
168          * DCCP_ACKPKTS_STATE_ECN_MARKED
169          */
170         if (dp->dccps_options.dccpo_send_ack_vector) {
171                 struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
172
173                 if (dccp_ackpkts_add(dp->dccps_hc_rx_ackpkts,
174                                      DCCP_SKB_CB(skb)->dccpd_seq,
175                                      DCCP_ACKPKTS_STATE_RECEIVED)) {
176                         LIMIT_NETDEBUG(KERN_WARNING "DCCP: acknowledgeable "
177                                                     "packets buffer full!\n");
178                         ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
179                         inet_csk_schedule_ack(sk);
180                         inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
181                                                   TCP_DELACK_MIN,
182                                                   DCCP_RTO_MAX);
183                         goto discard;
184                 }
185
186                 /*
187                  * FIXME: this activation is probably wrong, have to study more
188                  * TCP delack machinery and how it fits into DCCP draft, but
189                  * for now it kinda "works" 8)
190                  */
191                 if (!inet_csk_ack_scheduled(sk)) {
192                         inet_csk_schedule_ack(sk);
193                         inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 5 * HZ,
194                                                   DCCP_RTO_MAX);
195                 }
196         }
197
198         ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
199         ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
200
201         switch (dccp_hdr(skb)->dccph_type) {
202         case DCCP_PKT_DATAACK:
203         case DCCP_PKT_DATA:
204                 /*
205                  * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
206                  * option if it is.
207                  */
208                 __skb_pull(skb, dh->dccph_doff * 4);
209                 __skb_queue_tail(&sk->sk_receive_queue, skb);
210                 skb_set_owner_r(skb, sk);
211                 sk->sk_data_ready(sk, 0);
212                 return 0;
213         case DCCP_PKT_ACK:
214                 goto discard;
215         case DCCP_PKT_RESET:
216                 /*
217                  *  Step 9: Process Reset
218                  *      If P.type == Reset,
219                  *              Tear down connection
220                  *              S.state := TIMEWAIT
221                  *              Set TIMEWAIT timer
222                  *              Drop packet and return
223                 */
224                 dccp_fin(sk, skb);
225                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
226                 return 0;
227         case DCCP_PKT_CLOSEREQ:
228                 dccp_rcv_closereq(sk, skb);
229                 goto discard;
230         case DCCP_PKT_CLOSE:
231                 dccp_rcv_close(sk, skb);
232                 return 0;
233         case DCCP_PKT_REQUEST:
234                 /* Step 7 
235                  *   or (S.is_server and P.type == Response)
236                  *   or (S.is_client and P.type == Request)
237                  *   or (S.state >= OPEN and P.type == Request
238                  *      and P.seqno >= S.OSR)
239                  *    or (S.state >= OPEN and P.type == Response
240                  *      and P.seqno >= S.OSR)
241                  *    or (S.state == RESPOND and P.type == Data),
242                  *  Send Sync packet acknowledging P.seqno
243                  *  Drop packet and return
244                  */
245                 if (dp->dccps_role != DCCP_ROLE_LISTEN)
246                         goto send_sync;
247                 goto check_seq;
248         case DCCP_PKT_RESPONSE:
249                 if (dp->dccps_role != DCCP_ROLE_CLIENT)
250                         goto send_sync;
251 check_seq:
252                 if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
253 send_sync:
254                         dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
255                                        DCCP_PKT_SYNC);
256                 }
257                 break;
258         case DCCP_PKT_SYNC:
259                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
260                                DCCP_PKT_SYNCACK);
261                 /*
262                  * From the draft:
263                  *
264                  * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
265                  * MAY have non-zero-length application data areas, whose
266                  * contents * receivers MUST ignore.
267                  */
268                 goto discard;
269         }
270
271         DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
272 discard:
273         __kfree_skb(skb);
274         return 0;
275 }
276
277 static int dccp_rcv_request_sent_state_process(struct sock *sk,
278                                                struct sk_buff *skb,
279                                                const struct dccp_hdr *dh,
280                                                const unsigned len)
281 {
282         /* 
283          *  Step 4: Prepare sequence numbers in REQUEST
284          *     If S.state == REQUEST,
285          *        If (P.type == Response or P.type == Reset)
286          *              and S.AWL <= P.ackno <= S.AWH,
287          *           / * Set sequence number variables corresponding to the
288          *              other endpoint, so P will pass the tests in Step 6 * /
289          *           Set S.GSR, S.ISR, S.SWL, S.SWH
290          *           / * Response processing continues in Step 10; Reset
291          *              processing continues in Step 9 * /
292         */
293         if (dh->dccph_type == DCCP_PKT_RESPONSE) {
294                 const struct inet_connection_sock *icsk = inet_csk(sk);
295                 struct dccp_sock *dp = dccp_sk(sk);
296
297                 /* Stop the REQUEST timer */
298                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
299                 BUG_TRAP(sk->sk_send_head != NULL);
300                 __kfree_skb(sk->sk_send_head);
301                 sk->sk_send_head = NULL;
302
303                 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
304                                dp->dccps_awl, dp->dccps_awh)) {
305                         dccp_pr_debug("invalid ackno: S.AWL=%llu, "
306                                       "P.ackno=%llu, S.AWH=%llu \n",
307                                       (unsigned long long)dp->dccps_awl,
308                            (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
309                                       (unsigned long long)dp->dccps_awh);
310                         goto out_invalid_packet;
311                 }
312
313                 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
314                 dccp_update_gsr(sk, dp->dccps_isr);
315                 /*
316                  * SWL and AWL are initially adjusted so that they are not less than
317                  * the initial Sequence Numbers received and sent, respectively:
318                  *      SWL := max(GSR + 1 - floor(W/4), ISR),
319                  *      AWL := max(GSS - W' + 1, ISS).
320                  * These adjustments MUST be applied only at the beginning of the
321                  * connection.
322                  *
323                  * AWL was adjusted in dccp_v4_connect -acme
324                  */
325                 dccp_set_seqno(&dp->dccps_swl,
326                                max48(dp->dccps_swl, dp->dccps_isr));
327
328                 if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 ||
329                     ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
330                         ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
331                         ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
332                         /* FIXME: send appropriate RESET code */
333                         goto out_invalid_packet;
334                 }
335
336                 dccp_sync_mss(sk, dp->dccps_pmtu_cookie);
337
338                 /*
339                  *    Step 10: Process REQUEST state (second part)
340                  *       If S.state == REQUEST,
341                  *        / * If we get here, P is a valid Response from the
342                  *            server (see Step 4), and we should move to
343                  *            PARTOPEN state. PARTOPEN means send an Ack,
344                  *            don't send Data packets, retransmit Acks
345                  *            periodically, and always include any Init Cookie
346                  *            from the Response * /
347                  *        S.state := PARTOPEN
348                  *        Set PARTOPEN timer
349                  *        Continue with S.state == PARTOPEN
350                  *        / * Step 12 will send the Ack completing the
351                  *            three-way handshake * /
352                  */
353                 dccp_set_state(sk, DCCP_PARTOPEN);
354
355                 /* Make sure socket is routed, for correct metrics. */
356                 inet_sk_rebuild_header(sk);
357
358                 if (!sock_flag(sk, SOCK_DEAD)) {
359                         sk->sk_state_change(sk);
360                         sk_wake_async(sk, 0, POLL_OUT);
361                 }
362
363                 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
364                     icsk->icsk_accept_queue.rskq_defer_accept) {
365                         /* Save one ACK. Data will be ready after
366                          * several ticks, if write_pending is set.
367                          *
368                          * It may be deleted, but with this feature tcpdumps
369                          * look so _wonderfully_ clever, that I was not able
370                          * to stand against the temptation 8)     --ANK
371                          */
372                         /*
373                          * OK, in DCCP we can as well do a similar trick, its
374                          * even in the draft, but there is no need for us to
375                          * schedule an ack here, as dccp_sendmsg does this for
376                          * us, also stated in the draft. -acme
377                          */
378                         __kfree_skb(skb);
379                         return 0;
380                 } 
381                 dccp_send_ack(sk);
382                 return -1;
383         }
384
385 out_invalid_packet:
386         return 1; /* dccp_v4_do_rcv will send a reset, but...
387                      FIXME: the reset code should be
388                             DCCP_RESET_CODE_PACKET_ERROR */
389 }
390
391 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
392                                                    struct sk_buff *skb,
393                                                    const struct dccp_hdr *dh,
394                                                    const unsigned len)
395 {
396         int queued = 0;
397
398         switch (dh->dccph_type) {
399         case DCCP_PKT_RESET:
400                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
401                 break;
402         case DCCP_PKT_DATAACK:
403         case DCCP_PKT_ACK:
404                 /*
405                  * FIXME: we should be reseting the PARTOPEN (DELACK) timer
406                  * here but only if we haven't used the DELACK timer for
407                  * something else, like sending a delayed ack for a TIMESTAMP
408                  * echo, etc, for now were not clearing it, sending an extra
409                  * ACK when there is nothing else to do in DELACK is not a big
410                  * deal after all.
411                  */
412
413                 /* Stop the PARTOPEN timer */
414                 if (sk->sk_state == DCCP_PARTOPEN)
415                         inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
416
417                 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
418                 dccp_set_state(sk, DCCP_OPEN);
419
420                 if (dh->dccph_type == DCCP_PKT_DATAACK) {
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         const int old_state = sk->sk_state;
436         int queued = 0;
437
438         /*
439          *  Step 3: Process LISTEN state
440          *      (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
441          *
442          *     If S.state == LISTEN,
443          *        If P.type == Request or P contains a valid Init Cookie
444          *              option,
445          *           * Must scan the packet's options to check for an Init
446          *              Cookie.  Only the Init Cookie is processed here,
447          *              however; other options are processed in Step 8.  This
448          *              scan need only be performed if the endpoint uses Init
449          *              Cookies *
450          *           * Generate a new socket and switch to that socket *
451          *           Set S := new socket for this port pair
452          *           S.state = RESPOND
453          *           Choose S.ISS (initial seqno) or set from Init Cookie
454          *           Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
455          *           Continue with S.state == RESPOND
456          *           * A Response packet will be generated in Step 11 *
457          *        Otherwise,
458          *           Generate Reset(No Connection) unless P.type == Reset
459          *           Drop packet and return
460          *
461          * NOTE: the check for the packet types is done in
462          *       dccp_rcv_state_process
463          */
464         if (sk->sk_state == DCCP_LISTEN) {
465                 if (dh->dccph_type == DCCP_PKT_REQUEST) {
466                         if (dccp_v4_conn_request(sk, skb) < 0)
467                                 return 1;
468
469                         /* FIXME: do congestion control initialization */
470                         goto discard;
471                 }
472                 if (dh->dccph_type == DCCP_PKT_RESET)
473                         goto discard;
474
475                 /* Caller (dccp_v4_do_rcv) will send Reset(No Connection)*/
476                 return 1;
477         }
478
479         if (sk->sk_state != DCCP_REQUESTING) {
480                 if (dccp_check_seqno(sk, skb))
481                         goto discard;
482
483                 /*
484                  * Step 8: Process options and mark acknowledgeable
485                  */
486                 if (dccp_parse_options(sk, skb))
487                         goto discard;
488
489                 if (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
490                     DCCP_PKT_WITHOUT_ACK_SEQ)
491                         dccp_event_ack_recv(sk, skb);
492
493                 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
494                 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
495
496                 /*
497                  * FIXME: check ECN to see if we should use
498                  * DCCP_ACKPKTS_STATE_ECN_MARKED
499                  */
500                 if (dp->dccps_options.dccpo_send_ack_vector) {
501                         if (dccp_ackpkts_add(dp->dccps_hc_rx_ackpkts,
502                                              DCCP_SKB_CB(skb)->dccpd_seq,
503                                              DCCP_ACKPKTS_STATE_RECEIVED))
504                                 goto discard;
505                         /*
506                          * FIXME: this activation is probably wrong, have to
507                          * study more TCP delack machinery and how it fits into
508                          * DCCP draft, but for now it kinda "works" 8)
509                          */
510                         if ((dp->dccps_hc_rx_ackpkts->dccpap_ack_seqno ==
511                              DCCP_MAX_SEQNO + 1) &&
512                             !inet_csk_ack_scheduled(sk)) {
513                                 inet_csk_schedule_ack(sk);
514                                 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
515                                                           TCP_DELACK_MIN,
516                                                           DCCP_RTO_MAX);
517                         }
518                 }
519         }
520
521         /*
522          *  Step 9: Process Reset
523          *      If P.type == Reset,
524          *              Tear down connection
525          *              S.state := TIMEWAIT
526          *              Set TIMEWAIT timer
527          *              Drop packet and return
528         */
529         if (dh->dccph_type == DCCP_PKT_RESET) {
530                 /*
531                  * Queue the equivalent of TCP fin so that dccp_recvmsg
532                  * exits the loop
533                  */
534                 dccp_fin(sk, skb);
535                 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
536                 return 0;
537                 /*
538                  *   Step 7: Check for unexpected packet types
539                  *      If (S.is_server and P.type == CloseReq)
540                  *          or (S.is_server and P.type == Response)
541                  *          or (S.is_client and P.type == Request)
542                  *          or (S.state == RESPOND and P.type == Data),
543                  *        Send Sync packet acknowledging P.seqno
544                  *        Drop packet and return
545                  */
546         } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
547                     (dh->dccph_type == DCCP_PKT_RESPONSE ||
548                      dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
549                     (dp->dccps_role == DCCP_ROLE_CLIENT &&
550                      dh->dccph_type == DCCP_PKT_REQUEST) ||
551                     (sk->sk_state == DCCP_RESPOND &&
552                      dh->dccph_type == DCCP_PKT_DATA)) {
553                 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
554                                DCCP_PKT_SYNC);
555                 goto discard;
556         } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
557                 dccp_rcv_closereq(sk, skb);
558                 goto discard;
559         } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
560                 dccp_rcv_close(sk, skb);
561                 return 0;
562         }
563
564         switch (sk->sk_state) {
565         case DCCP_CLOSED:
566                 return 1;
567
568         case DCCP_REQUESTING:
569                 /* FIXME: do congestion control initialization */
570
571                 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
572                 if (queued >= 0)
573                         return queued;
574
575                 __kfree_skb(skb);
576                 return 0;
577
578         case DCCP_RESPOND:
579         case DCCP_PARTOPEN:
580                 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
581                                                                  dh, len);
582                 break;
583         }
584
585         if (dh->dccph_type == DCCP_PKT_ACK ||
586             dh->dccph_type == DCCP_PKT_DATAACK) {
587                 switch (old_state) {
588                 case DCCP_PARTOPEN:
589                         sk->sk_state_change(sk);
590                         sk_wake_async(sk, 0, POLL_OUT);
591                         break;
592                 }
593         }
594
595         if (!queued) { 
596 discard:
597                 __kfree_skb(skb);
598         }
599         return 0;
600 }