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dccp ccid-2: Ack Vector interface clean-up
[linux-2.6/libata-dev.git] / net / dccp / input.c
blob70ad0ba72146654dd92f58245c5f13b0350c7b6f
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 /* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */
23 int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8;
24
25 static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb)
26 {
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_fin(struct sock *sk, struct sk_buff *skb)
34 {
35 /*
36 * On receiving Close/CloseReq, both RD/WR shutdown are performed.
37 * RFC 4340, 8.3 says that we MAY send further Data/DataAcks after
38 * receiving the closing segment, but there is no guarantee that such
39 * data will be processed at all.
40 */
41 sk->sk_shutdown = SHUTDOWN_MASK;
42 sock_set_flag(sk, SOCK_DONE);
43 dccp_enqueue_skb(sk, skb);
44 }
45
46 static int dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
47 {
48 int queued = 0;
49
50 switch (sk->sk_state) {
51 /*
52 * We ignore Close when received in one of the following states:
53 * - CLOSED (may be a late or duplicate packet)
54 * - PASSIVE_CLOSEREQ (the peer has sent a CloseReq earlier)
55 * - RESPOND (already handled by dccp_check_req)
56 */
57 case DCCP_CLOSING:
58 /*
59 * Simultaneous-close: receiving a Close after sending one. This
60 * can happen if both client and server perform active-close and
61 * will result in an endless ping-pong of crossing and retrans-
62 * mitted Close packets, which only terminates when one of the
63 * nodes times out (min. 64 seconds). Quicker convergence can be
64 * achieved when one of the nodes acts as tie-breaker.
65 * This is ok as both ends are done with data transfer and each
66 * end is just waiting for the other to acknowledge termination.
67 */
68 if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT)
69 break;
70 /* fall through */
71 case DCCP_REQUESTING:
72 case DCCP_ACTIVE_CLOSEREQ:
73 dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
74 dccp_done(sk);
75 break;
76 case DCCP_OPEN:
77 case DCCP_PARTOPEN:
78 /* Give waiting application a chance to read pending data */
79 queued = 1;
80 dccp_fin(sk, skb);
81 dccp_set_state(sk, DCCP_PASSIVE_CLOSE);
82 /* fall through */
83 case DCCP_PASSIVE_CLOSE:
84 /*
85 * Retransmitted Close: we have already enqueued the first one.
86 */
87 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
88 }
89 return queued;
90 }
91
92 static int dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
93 {
94 int queued = 0;
95
96 /*
97 * Step 7: Check for unexpected packet types
98 * If (S.is_server and P.type == CloseReq)
99 * Send Sync packet acknowledging P.seqno
100 * Drop packet and return
101 */
102 if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
103 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
104 return queued;
105 }
106
107 /* Step 13: process relevant Client states < CLOSEREQ */
108 switch (sk->sk_state) {
109 case DCCP_REQUESTING:
110 dccp_send_close(sk, 0);
111 dccp_set_state(sk, DCCP_CLOSING);
112 break;
113 case DCCP_OPEN:
114 case DCCP_PARTOPEN:
115 /* Give waiting application a chance to read pending data */
116 queued = 1;
117 dccp_fin(sk, skb);
118 dccp_set_state(sk, DCCP_PASSIVE_CLOSEREQ);
119 /* fall through */
120 case DCCP_PASSIVE_CLOSEREQ:
121 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
122 }
123 return queued;
124 }
125
126 static u8 dccp_reset_code_convert(const u8 code)
127 {
128 const u8 error_code[] = {
129 [DCCP_RESET_CODE_CLOSED] = 0, /* normal termination */
130 [DCCP_RESET_CODE_UNSPECIFIED] = 0, /* nothing known */
131 [DCCP_RESET_CODE_ABORTED] = ECONNRESET,
132
133 [DCCP_RESET_CODE_NO_CONNECTION] = ECONNREFUSED,
134 [DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED,
135 [DCCP_RESET_CODE_TOO_BUSY] = EUSERS,
136 [DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT,
137
138 [DCCP_RESET_CODE_PACKET_ERROR] = ENOMSG,
139 [DCCP_RESET_CODE_BAD_INIT_COOKIE] = EBADR,
140 [DCCP_RESET_CODE_BAD_SERVICE_CODE] = EBADRQC,
141 [DCCP_RESET_CODE_OPTION_ERROR] = EILSEQ,
142 [DCCP_RESET_CODE_MANDATORY_ERROR] = EOPNOTSUPP,
143 };
144
145 return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code];
146 }
147
148 static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb)
149 {
150 u8 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code);
151
152 sk->sk_err = err;
153
154 /* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */
155 dccp_fin(sk, skb);
156
157 if (err && !sock_flag(sk, SOCK_DEAD))
158 sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
159 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
160 }
161
162 static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
163 {
164 struct dccp_sock *dp = dccp_sk(sk);
165
166 if (dp->dccps_hc_rx_ackvec != NULL)
167 dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
168 DCCP_SKB_CB(skb)->dccpd_ack_seq);
169 }
170
171 static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb)
172 {
173 const struct dccp_sock *dp = dccp_sk(sk);
174
175 /* Don't deliver to RX CCID when node has shut down read end. */
176 if (!(sk->sk_shutdown & RCV_SHUTDOWN))
177 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
178 /*
179 * Until the TX queue has been drained, we can not honour SHUT_WR, since
180 * we need received feedback as input to adjust congestion control.
181 */
182 if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN))
183 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
184 }
185
186 static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
187 {
188 const struct dccp_hdr *dh = dccp_hdr(skb);
189 struct dccp_sock *dp = dccp_sk(sk);
190 u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq,
191 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
192
193 /*
194 * Step 5: Prepare sequence numbers for Sync
195 * If P.type == Sync or P.type == SyncAck,
196 * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
197 * / * P is valid, so update sequence number variables
198 * accordingly. After this update, P will pass the tests
199 * in Step 6. A SyncAck is generated if necessary in
200 * Step 15 * /
201 * Update S.GSR, S.SWL, S.SWH
202 * Otherwise,
203 * Drop packet and return
204 */
205 if (dh->dccph_type == DCCP_PKT_SYNC ||
206 dh->dccph_type == DCCP_PKT_SYNCACK) {
207 if (between48(ackno, dp->dccps_awl, dp->dccps_awh) &&
208 dccp_delta_seqno(dp->dccps_swl, seqno) >= 0)
209 dccp_update_gsr(sk, seqno);
210 else
211 return -1;
212 }
213
214 /*
215 * Step 6: Check sequence numbers
216 * Let LSWL = S.SWL and LAWL = S.AWL
217 * If P.type == CloseReq or P.type == Close or P.type == Reset,
218 * LSWL := S.GSR + 1, LAWL := S.GAR
219 * If LSWL <= P.seqno <= S.SWH
220 * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
221 * Update S.GSR, S.SWL, S.SWH
222 * If P.type != Sync,
223 * Update S.GAR
224 */
225 lswl = dp->dccps_swl;
226 lawl = dp->dccps_awl;
227
228 if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
229 dh->dccph_type == DCCP_PKT_CLOSE ||
230 dh->dccph_type == DCCP_PKT_RESET) {
231 lswl = ADD48(dp->dccps_gsr, 1);
232 lawl = dp->dccps_gar;
233 }
234
235 if (between48(seqno, lswl, dp->dccps_swh) &&
236 (ackno == DCCP_PKT_WITHOUT_ACK_SEQ ||
237 between48(ackno, lawl, dp->dccps_awh))) {
238 dccp_update_gsr(sk, seqno);
239
240 if (dh->dccph_type != DCCP_PKT_SYNC &&
241 (ackno != DCCP_PKT_WITHOUT_ACK_SEQ))
242 dp->dccps_gar = ackno;
243 } else {
244 unsigned long now = jiffies;
245 /*
246 * Step 6: Check sequence numbers
247 * Otherwise,
248 * If P.type == Reset,
249 * Send Sync packet acknowledging S.GSR
250 * Otherwise,
251 * Send Sync packet acknowledging P.seqno
252 * Drop packet and return
253 *
254 * These Syncs are rate-limited as per RFC 4340, 7.5.4:
255 * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second.
256 */
257 if (time_before(now, (dp->dccps_rate_last +
258 sysctl_dccp_sync_ratelimit)))
259 return 0;
260
261 DCCP_WARN("DCCP: Step 6 failed for %s packet, "
262 "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
263 "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
264 "sending SYNC...\n", dccp_packet_name(dh->dccph_type),
265 (unsigned long long) lswl, (unsigned long long) seqno,
266 (unsigned long long) dp->dccps_swh,
267 (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist"
268 : "exists",
269 (unsigned long long) lawl, (unsigned long long) ackno,
270 (unsigned long long) dp->dccps_awh);
271
272 dp->dccps_rate_last = now;
273
274 if (dh->dccph_type == DCCP_PKT_RESET)
275 seqno = dp->dccps_gsr;
276 dccp_send_sync(sk, seqno, DCCP_PKT_SYNC);
277 return -1;
278 }
279
280 return 0;
281 }
282
283 static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
284 const struct dccp_hdr *dh, const unsigned len)
285 {
286 struct dccp_sock *dp = dccp_sk(sk);
287
288 switch (dccp_hdr(skb)->dccph_type) {
289 case DCCP_PKT_DATAACK:
290 case DCCP_PKT_DATA:
291 /*
292 * FIXME: schedule DATA_DROPPED (RFC 4340, 11.7.2) if and when
293 * - sk_shutdown == RCV_SHUTDOWN, use Code 1, "Not Listening"
294 * - sk_receive_queue is full, use Code 2, "Receive Buffer"
295 */
296 dccp_enqueue_skb(sk, skb);
297 return 0;
298 case DCCP_PKT_ACK:
299 goto discard;
300 case DCCP_PKT_RESET:
301 /*
302 * Step 9: Process Reset
303 * If P.type == Reset,
304 * Tear down connection
305 * S.state := TIMEWAIT
306 * Set TIMEWAIT timer
307 * Drop packet and return
308 */
309 dccp_rcv_reset(sk, skb);
310 return 0;
311 case DCCP_PKT_CLOSEREQ:
312 if (dccp_rcv_closereq(sk, skb))
313 return 0;
314 goto discard;
315 case DCCP_PKT_CLOSE:
316 if (dccp_rcv_close(sk, skb))
317 return 0;
318 goto discard;
319 case DCCP_PKT_REQUEST:
320 /* Step 7
321 * or (S.is_server and P.type == Response)
322 * or (S.is_client and P.type == Request)
323 * or (S.state >= OPEN and P.type == Request
324 * and P.seqno >= S.OSR)
325 * or (S.state >= OPEN and P.type == Response
326 * and P.seqno >= S.OSR)
327 * or (S.state == RESPOND and P.type == Data),
328 * Send Sync packet acknowledging P.seqno
329 * Drop packet and return
330 */
331 if (dp->dccps_role != DCCP_ROLE_LISTEN)
332 goto send_sync;
333 goto check_seq;
334 case DCCP_PKT_RESPONSE:
335 if (dp->dccps_role != DCCP_ROLE_CLIENT)
336 goto send_sync;
337 check_seq:
338 if (dccp_delta_seqno(dp->dccps_osr,
339 DCCP_SKB_CB(skb)->dccpd_seq) >= 0) {
340 send_sync:
341 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
342 DCCP_PKT_SYNC);
343 }
344 break;
345 case DCCP_PKT_SYNC:
346 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
347 DCCP_PKT_SYNCACK);
348 /*
349 * From RFC 4340, sec. 5.7
350 *
351 * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
352 * MAY have non-zero-length application data areas, whose
353 * contents receivers MUST ignore.
354 */
355 goto discard;
356 }
357
358 DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
359 discard:
360 __kfree_skb(skb);
361 return 0;
362 }
363
364 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
365 const struct dccp_hdr *dh, const unsigned len)
366 {
367 struct dccp_sock *dp = dccp_sk(sk);
368
369 if (dccp_check_seqno(sk, skb))
370 goto discard;
371
372 if (dccp_parse_options(sk, NULL, skb))
373 return 1;
374
375 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
376 dccp_event_ack_recv(sk, skb);
377
378 if (dp->dccps_hc_rx_ackvec != NULL &&
379 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
380 DCCP_SKB_CB(skb)->dccpd_seq, DCCPAV_RECEIVED))
381 goto discard;
382 dccp_deliver_input_to_ccids(sk, skb);
383
384 return __dccp_rcv_established(sk, skb, dh, len);
385 discard:
386 __kfree_skb(skb);
387 return 0;
388 }
389
390 EXPORT_SYMBOL_GPL(dccp_rcv_established);
391
392 static int dccp_rcv_request_sent_state_process(struct sock *sk,
393 struct sk_buff *skb,
394 const struct dccp_hdr *dh,
395 const unsigned len)
396 {
397 /*
398 * Step 4: Prepare sequence numbers in REQUEST
399 * If S.state == REQUEST,
400 * If (P.type == Response or P.type == Reset)
401 * and S.AWL <= P.ackno <= S.AWH,
402 * / * Set sequence number variables corresponding to the
403 * other endpoint, so P will pass the tests in Step 6 * /
404 * Set S.GSR, S.ISR, S.SWL, S.SWH
405 * / * Response processing continues in Step 10; Reset
406 * processing continues in Step 9 * /
407 */
408 if (dh->dccph_type == DCCP_PKT_RESPONSE) {
409 const struct inet_connection_sock *icsk = inet_csk(sk);
410 struct dccp_sock *dp = dccp_sk(sk);
411 long tstamp = dccp_timestamp();
412
413 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
414 dp->dccps_awl, dp->dccps_awh)) {
415 dccp_pr_debug("invalid ackno: S.AWL=%llu, "
416 "P.ackno=%llu, S.AWH=%llu \n",
417 (unsigned long long)dp->dccps_awl,
418 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
419 (unsigned long long)dp->dccps_awh);
420 goto out_invalid_packet;
421 }
422
423 /*
424 * If option processing (Step 8) failed, return 1 here so that
425 * dccp_v4_do_rcv() sends a Reset. The Reset code depends on
426 * the option type and is set in dccp_parse_options().
427 */
428 if (dccp_parse_options(sk, NULL, skb))
429 return 1;
430
431 /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */
432 if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
433 dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp -
434 dp->dccps_options_received.dccpor_timestamp_echo));
435
436 /* Stop the REQUEST timer */
437 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
438 WARN_ON(sk->sk_send_head == NULL);
439 kfree_skb(sk->sk_send_head);
440 sk->sk_send_head = NULL;
441
442 /*
443 * Set ISR, GSR from packet. ISS was set in dccp_v{4,6}_connect
444 * and GSS in dccp_transmit_skb(). Setting AWL/AWH and SWL/SWH
445 * is done as part of activating the feature values below, since
446 * these settings depend on the local/remote Sequence Window
447 * features, which were undefined or not confirmed until now.
448 */
449 dp->dccps_gsr = dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
450
451 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
452
453 /*
454 * Step 10: Process REQUEST state (second part)
455 * If S.state == REQUEST,
456 * / * If we get here, P is a valid Response from the
457 * server (see Step 4), and we should move to
458 * PARTOPEN state. PARTOPEN means send an Ack,
459 * don't send Data packets, retransmit Acks
460 * periodically, and always include any Init Cookie
461 * from the Response * /
462 * S.state := PARTOPEN
463 * Set PARTOPEN timer
464 * Continue with S.state == PARTOPEN
465 * / * Step 12 will send the Ack completing the
466 * three-way handshake * /
467 */
468 dccp_set_state(sk, DCCP_PARTOPEN);
469
470 /*
471 * If feature negotiation was successful, activate features now;
472 * an activation failure means that this host could not activate
473 * one ore more features (e.g. insufficient memory), which would
474 * leave at least one feature in an undefined state.
475 */
476 if (dccp_feat_activate_values(sk, &dp->dccps_featneg))
477 goto unable_to_proceed;
478
479 /* Make sure socket is routed, for correct metrics. */
480 icsk->icsk_af_ops->rebuild_header(sk);
481
482 if (!sock_flag(sk, SOCK_DEAD)) {
483 sk->sk_state_change(sk);
484 sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
485 }
486
487 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
488 icsk->icsk_accept_queue.rskq_defer_accept) {
489 /* Save one ACK. Data will be ready after
490 * several ticks, if write_pending is set.
491 *
492 * It may be deleted, but with this feature tcpdumps
493 * look so _wonderfully_ clever, that I was not able
494 * to stand against the temptation 8) --ANK
495 */
496 /*
497 * OK, in DCCP we can as well do a similar trick, its
498 * even in the draft, but there is no need for us to
499 * schedule an ack here, as dccp_sendmsg does this for
500 * us, also stated in the draft. -acme
501 */
502 __kfree_skb(skb);
503 return 0;
504 }
505 dccp_send_ack(sk);
506 return -1;
507 }
508
509 out_invalid_packet:
510 /* dccp_v4_do_rcv will send a reset */
511 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
512 return 1;
513
514 unable_to_proceed:
515 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_ABORTED;
516 /*
517 * We mark this socket as no longer usable, so that the loop in
518 * dccp_sendmsg() terminates and the application gets notified.
519 */
520 dccp_set_state(sk, DCCP_CLOSED);
521 sk->sk_err = ECOMM;
522 return 1;
523 }
524
525 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
526 struct sk_buff *skb,
527 const struct dccp_hdr *dh,
528 const unsigned len)
529 {
530 int queued = 0;
531
532 switch (dh->dccph_type) {
533 case DCCP_PKT_RESET:
534 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
535 break;
536 case DCCP_PKT_DATA:
537 if (sk->sk_state == DCCP_RESPOND)
538 break;
539 case DCCP_PKT_DATAACK:
540 case DCCP_PKT_ACK:
541 /*
542 * FIXME: we should be reseting the PARTOPEN (DELACK) timer
543 * here but only if we haven't used the DELACK timer for
544 * something else, like sending a delayed ack for a TIMESTAMP
545 * echo, etc, for now were not clearing it, sending an extra
546 * ACK when there is nothing else to do in DELACK is not a big
547 * deal after all.
548 */
549
550 /* Stop the PARTOPEN timer */
551 if (sk->sk_state == DCCP_PARTOPEN)
552 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
553
554 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
555 dccp_set_state(sk, DCCP_OPEN);
556
557 if (dh->dccph_type == DCCP_PKT_DATAACK ||
558 dh->dccph_type == DCCP_PKT_DATA) {
559 __dccp_rcv_established(sk, skb, dh, len);
560 queued = 1; /* packet was queued
561 (by __dccp_rcv_established) */
562 }
563 break;
564 }
565
566 return queued;
567 }
568
569 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
570 struct dccp_hdr *dh, unsigned len)
571 {
572 struct dccp_sock *dp = dccp_sk(sk);
573 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
574 const int old_state = sk->sk_state;
575 int queued = 0;
576
577 /*
578 * Step 3: Process LISTEN state
579 *
580 * If S.state == LISTEN,
581 * If P.type == Request or P contains a valid Init Cookie option,
582 * (* Must scan the packet's options to check for Init
583 * Cookies. Only Init Cookies are processed here,
584 * however; other options are processed in Step 8. This
585 * scan need only be performed if the endpoint uses Init
586 * Cookies *)
587 * (* Generate a new socket and switch to that socket *)
588 * Set S := new socket for this port pair
589 * S.state = RESPOND
590 * Choose S.ISS (initial seqno) or set from Init Cookies
591 * Initialize S.GAR := S.ISS
592 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
593 * Cookies Continue with S.state == RESPOND
594 * (* A Response packet will be generated in Step 11 *)
595 * Otherwise,
596 * Generate Reset(No Connection) unless P.type == Reset
597 * Drop packet and return
598 */
599 if (sk->sk_state == DCCP_LISTEN) {
600 if (dh->dccph_type == DCCP_PKT_REQUEST) {
601 if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
602 skb) < 0)
603 return 1;
604 goto discard;
605 }
606 if (dh->dccph_type == DCCP_PKT_RESET)
607 goto discard;
608
609 /* Caller (dccp_v4_do_rcv) will send Reset */
610 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
611 return 1;
612 }
613
614 if (sk->sk_state != DCCP_REQUESTING && sk->sk_state != DCCP_RESPOND) {
615 if (dccp_check_seqno(sk, skb))
616 goto discard;
617
618 /*
619 * Step 8: Process options and mark acknowledgeable
620 */
621 if (dccp_parse_options(sk, NULL, skb))
622 return 1;
623
624 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
625 dccp_event_ack_recv(sk, skb);
626
627 if (dp->dccps_hc_rx_ackvec != NULL &&
628 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
629 DCCP_SKB_CB(skb)->dccpd_seq, DCCPAV_RECEIVED))
630 goto discard;
631
632 dccp_deliver_input_to_ccids(sk, skb);
633 }
634
635 /*
636 * Step 9: Process Reset
637 * If P.type == Reset,
638 * Tear down connection
639 * S.state := TIMEWAIT
640 * Set TIMEWAIT timer
641 * Drop packet and return
642 */
643 if (dh->dccph_type == DCCP_PKT_RESET) {
644 dccp_rcv_reset(sk, skb);
645 return 0;
646 /*
647 * Step 7: Check for unexpected packet types
648 * If (S.is_server and P.type == Response)
649 * or (S.is_client and P.type == Request)
650 * or (S.state == RESPOND and P.type == Data),
651 * Send Sync packet acknowledging P.seqno
652 * Drop packet and return
653 */
654 } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
655 dh->dccph_type == DCCP_PKT_RESPONSE) ||
656 (dp->dccps_role == DCCP_ROLE_CLIENT &&
657 dh->dccph_type == DCCP_PKT_REQUEST) ||
658 (sk->sk_state == DCCP_RESPOND &&
659 dh->dccph_type == DCCP_PKT_DATA)) {
660 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
661 goto discard;
662 } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
663 if (dccp_rcv_closereq(sk, skb))
664 return 0;
665 goto discard;
666 } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
667 if (dccp_rcv_close(sk, skb))
668 return 0;
669 goto discard;
670 }
671
672 switch (sk->sk_state) {
673 case DCCP_CLOSED:
674 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
675 return 1;
676
677 case DCCP_REQUESTING:
678 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
679 if (queued >= 0)
680 return queued;
681
682 __kfree_skb(skb);
683 return 0;
684
685 case DCCP_RESPOND:
686 case DCCP_PARTOPEN:
687 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
688 dh, len);
689 break;
690 }
691
692 if (dh->dccph_type == DCCP_PKT_ACK ||
693 dh->dccph_type == DCCP_PKT_DATAACK) {
694 switch (old_state) {
695 case DCCP_PARTOPEN:
696 sk->sk_state_change(sk);
697 sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
698 break;
699 }
700 } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
701 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
702 goto discard;
703 }
704
705 if (!queued) {
706 discard:
707 __kfree_skb(skb);
708 }
709 return 0;
710 }
711
712 EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
713
714 /**
715 * dccp_sample_rtt - Validate and finalise computation of RTT sample
716 * @delta: number of microseconds between packet and acknowledgment
717 * The routine is kept generic to work in different contexts. It should be
718 * called immediately when the ACK used for the RTT sample arrives.
719 */
720 u32 dccp_sample_rtt(struct sock *sk, long delta)
721 {
722 /* dccpor_elapsed_time is either zeroed out or set and > 0 */
723 delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10;
724
725 if (unlikely(delta <= 0)) {
726 DCCP_WARN("unusable RTT sample %ld, using min\n", delta);
727 return DCCP_SANE_RTT_MIN;
728 }
729 if (unlikely(delta > DCCP_SANE_RTT_MAX)) {
730 DCCP_WARN("RTT sample %ld too large, using max\n", delta);
731 return DCCP_SANE_RTT_MAX;
732 }
733
734 return delta;
735 }
736
737 EXPORT_SYMBOL_GPL(dccp_sample_rtt);
Linux 2.6 libata-dev (mirror)