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Driver core: Fix cleanup when failing device_add().
[wrt350n-kernel.git] / net / dccp / input.c
blob08392ed86c25403ea574c1e2b39786b8488e4625
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 (dccp_msk(sk)->dccpms_send_ack_vector)
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 goto discard;
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 (dccp_msk(sk)->dccpms_send_ack_vector &&
379 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
380 DCCP_SKB_CB(skb)->dccpd_seq,
381 DCCP_ACKVEC_STATE_RECEIVED))
382 goto discard;
383 dccp_deliver_input_to_ccids(sk, skb);
384
385 return __dccp_rcv_established(sk, skb, dh, len);
386 discard:
387 __kfree_skb(skb);
388 return 0;
389 }
390
391 EXPORT_SYMBOL_GPL(dccp_rcv_established);
392
393 static int dccp_rcv_request_sent_state_process(struct sock *sk,
394 struct sk_buff *skb,
395 const struct dccp_hdr *dh,
396 const unsigned len)
397 {
398 /*
399 * Step 4: Prepare sequence numbers in REQUEST
400 * If S.state == REQUEST,
401 * If (P.type == Response or P.type == Reset)
402 * and S.AWL <= P.ackno <= S.AWH,
403 * / * Set sequence number variables corresponding to the
404 * other endpoint, so P will pass the tests in Step 6 * /
405 * Set S.GSR, S.ISR, S.SWL, S.SWH
406 * / * Response processing continues in Step 10; Reset
407 * processing continues in Step 9 * /
408 */
409 if (dh->dccph_type == DCCP_PKT_RESPONSE) {
410 const struct inet_connection_sock *icsk = inet_csk(sk);
411 struct dccp_sock *dp = dccp_sk(sk);
412 long tstamp = dccp_timestamp();
413
414 /* Stop the REQUEST timer */
415 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
416 BUG_TRAP(sk->sk_send_head != NULL);
417 __kfree_skb(sk->sk_send_head);
418 sk->sk_send_head = NULL;
419
420 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
421 dp->dccps_awl, dp->dccps_awh)) {
422 dccp_pr_debug("invalid ackno: S.AWL=%llu, "
423 "P.ackno=%llu, S.AWH=%llu \n",
424 (unsigned long long)dp->dccps_awl,
425 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
426 (unsigned long long)dp->dccps_awh);
427 goto out_invalid_packet;
428 }
429
430 if (dccp_parse_options(sk, NULL, skb))
431 goto out_invalid_packet;
432
433 /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */
434 if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
435 dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp -
436 dp->dccps_options_received.dccpor_timestamp_echo));
437
438 if (dccp_msk(sk)->dccpms_send_ack_vector &&
439 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
440 DCCP_SKB_CB(skb)->dccpd_seq,
441 DCCP_ACKVEC_STATE_RECEIVED))
442 goto out_invalid_packet; /* FIXME: change error code */
443
444 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
445 dccp_update_gsr(sk, dp->dccps_isr);
446 /*
447 * SWL and AWL are initially adjusted so that they are not less than
448 * the initial Sequence Numbers received and sent, respectively:
449 * SWL := max(GSR + 1 - floor(W/4), ISR),
450 * AWL := max(GSS - W' + 1, ISS).
451 * These adjustments MUST be applied only at the beginning of the
452 * connection.
453 *
454 * AWL was adjusted in dccp_v4_connect -acme
455 */
456 dccp_set_seqno(&dp->dccps_swl,
457 max48(dp->dccps_swl, dp->dccps_isr));
458
459 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
460
461 /*
462 * Step 10: Process REQUEST state (second part)
463 * If S.state == REQUEST,
464 * / * If we get here, P is a valid Response from the
465 * server (see Step 4), and we should move to
466 * PARTOPEN state. PARTOPEN means send an Ack,
467 * don't send Data packets, retransmit Acks
468 * periodically, and always include any Init Cookie
469 * from the Response * /
470 * S.state := PARTOPEN
471 * Set PARTOPEN timer
472 * Continue with S.state == PARTOPEN
473 * / * Step 12 will send the Ack completing the
474 * three-way handshake * /
475 */
476 dccp_set_state(sk, DCCP_PARTOPEN);
477
478 /* Make sure socket is routed, for correct metrics. */
479 icsk->icsk_af_ops->rebuild_header(sk);
480
481 if (!sock_flag(sk, SOCK_DEAD)) {
482 sk->sk_state_change(sk);
483 sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
484 }
485
486 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
487 icsk->icsk_accept_queue.rskq_defer_accept) {
488 /* Save one ACK. Data will be ready after
489 * several ticks, if write_pending is set.
490 *
491 * It may be deleted, but with this feature tcpdumps
492 * look so _wonderfully_ clever, that I was not able
493 * to stand against the temptation 8) --ANK
494 */
495 /*
496 * OK, in DCCP we can as well do a similar trick, its
497 * even in the draft, but there is no need for us to
498 * schedule an ack here, as dccp_sendmsg does this for
499 * us, also stated in the draft. -acme
500 */
501 __kfree_skb(skb);
502 return 0;
503 }
504 dccp_send_ack(sk);
505 return -1;
506 }
507
508 out_invalid_packet:
509 /* dccp_v4_do_rcv will send a reset */
510 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
511 return 1;
512 }
513
514 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
515 struct sk_buff *skb,
516 const struct dccp_hdr *dh,
517 const unsigned len)
518 {
519 int queued = 0;
520
521 switch (dh->dccph_type) {
522 case DCCP_PKT_RESET:
523 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
524 break;
525 case DCCP_PKT_DATA:
526 if (sk->sk_state == DCCP_RESPOND)
527 break;
528 case DCCP_PKT_DATAACK:
529 case DCCP_PKT_ACK:
530 /*
531 * FIXME: we should be reseting the PARTOPEN (DELACK) timer
532 * here but only if we haven't used the DELACK timer for
533 * something else, like sending a delayed ack for a TIMESTAMP
534 * echo, etc, for now were not clearing it, sending an extra
535 * ACK when there is nothing else to do in DELACK is not a big
536 * deal after all.
537 */
538
539 /* Stop the PARTOPEN timer */
540 if (sk->sk_state == DCCP_PARTOPEN)
541 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
542
543 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
544 dccp_set_state(sk, DCCP_OPEN);
545
546 if (dh->dccph_type == DCCP_PKT_DATAACK ||
547 dh->dccph_type == DCCP_PKT_DATA) {
548 __dccp_rcv_established(sk, skb, dh, len);
549 queued = 1; /* packet was queued
550 (by __dccp_rcv_established) */
551 }
552 break;
553 }
554
555 return queued;
556 }
557
558 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
559 struct dccp_hdr *dh, unsigned len)
560 {
561 struct dccp_sock *dp = dccp_sk(sk);
562 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
563 const int old_state = sk->sk_state;
564 int queued = 0;
565
566 /*
567 * Step 3: Process LISTEN state
568 *
569 * If S.state == LISTEN,
570 * If P.type == Request or P contains a valid Init Cookie option,
571 * (* Must scan the packet's options to check for Init
572 * Cookies. Only Init Cookies are processed here,
573 * however; other options are processed in Step 8. This
574 * scan need only be performed if the endpoint uses Init
575 * Cookies *)
576 * (* Generate a new socket and switch to that socket *)
577 * Set S := new socket for this port pair
578 * S.state = RESPOND
579 * Choose S.ISS (initial seqno) or set from Init Cookies
580 * Initialize S.GAR := S.ISS
581 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
582 * Cookies Continue with S.state == RESPOND
583 * (* A Response packet will be generated in Step 11 *)
584 * Otherwise,
585 * Generate Reset(No Connection) unless P.type == Reset
586 * Drop packet and return
587 */
588 if (sk->sk_state == DCCP_LISTEN) {
589 if (dh->dccph_type == DCCP_PKT_REQUEST) {
590 if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
591 skb) < 0)
592 return 1;
593
594 /* FIXME: do congestion control initialization */
595 goto discard;
596 }
597 if (dh->dccph_type == DCCP_PKT_RESET)
598 goto discard;
599
600 /* Caller (dccp_v4_do_rcv) will send Reset */
601 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
602 return 1;
603 }
604
605 if (sk->sk_state != DCCP_REQUESTING) {
606 if (dccp_check_seqno(sk, skb))
607 goto discard;
608
609 /*
610 * Step 8: Process options and mark acknowledgeable
611 */
612 if (dccp_parse_options(sk, NULL, skb))
613 goto discard;
614
615 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
616 dccp_event_ack_recv(sk, skb);
617
618 if (dccp_msk(sk)->dccpms_send_ack_vector &&
619 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
620 DCCP_SKB_CB(skb)->dccpd_seq,
621 DCCP_ACKVEC_STATE_RECEIVED))
622 goto discard;
623
624 dccp_deliver_input_to_ccids(sk, skb);
625 }
626
627 /*
628 * Step 9: Process Reset
629 * If P.type == Reset,
630 * Tear down connection
631 * S.state := TIMEWAIT
632 * Set TIMEWAIT timer
633 * Drop packet and return
634 */
635 if (dh->dccph_type == DCCP_PKT_RESET) {
636 dccp_rcv_reset(sk, skb);
637 return 0;
638 /*
639 * Step 7: Check for unexpected packet types
640 * If (S.is_server and P.type == Response)
641 * or (S.is_client and P.type == Request)
642 * or (S.state == RESPOND and P.type == Data),
643 * Send Sync packet acknowledging P.seqno
644 * Drop packet and return
645 */
646 } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
647 dh->dccph_type == DCCP_PKT_RESPONSE) ||
648 (dp->dccps_role == DCCP_ROLE_CLIENT &&
649 dh->dccph_type == DCCP_PKT_REQUEST) ||
650 (sk->sk_state == DCCP_RESPOND &&
651 dh->dccph_type == DCCP_PKT_DATA)) {
652 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
653 goto discard;
654 } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
655 if (dccp_rcv_closereq(sk, skb))
656 return 0;
657 goto discard;
658 } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
659 if (dccp_rcv_close(sk, skb))
660 return 0;
661 goto discard;
662 }
663
664 switch (sk->sk_state) {
665 case DCCP_CLOSED:
666 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
667 return 1;
668
669 case DCCP_REQUESTING:
670 /* FIXME: do congestion control initialization */
671
672 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
673 if (queued >= 0)
674 return queued;
675
676 __kfree_skb(skb);
677 return 0;
678
679 case DCCP_RESPOND:
680 case DCCP_PARTOPEN:
681 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
682 dh, len);
683 break;
684 }
685
686 if (dh->dccph_type == DCCP_PKT_ACK ||
687 dh->dccph_type == DCCP_PKT_DATAACK) {
688 switch (old_state) {
689 case DCCP_PARTOPEN:
690 sk->sk_state_change(sk);
691 sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
692 break;
693 }
694 } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
695 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
696 goto discard;
697 }
698
699 if (!queued) {
700 discard:
701 __kfree_skb(skb);
702 }
703 return 0;
704 }
705
706 EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
707
708 /**
709 * dccp_sample_rtt - Validate and finalise computation of RTT sample
710 * @delta: number of microseconds between packet and acknowledgment
711 * The routine is kept generic to work in different contexts. It should be
712 * called immediately when the ACK used for the RTT sample arrives.
713 */
714 u32 dccp_sample_rtt(struct sock *sk, long delta)
715 {
716 /* dccpor_elapsed_time is either zeroed out or set and > 0 */
717 delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10;
718
719 if (unlikely(delta <= 0)) {
720 DCCP_WARN("unusable RTT sample %ld, using min\n", delta);
721 return DCCP_SANE_RTT_MIN;
722 }
723 if (unlikely(delta > DCCP_SANE_RTT_MAX)) {
724 DCCP_WARN("RTT sample %ld too large, using max\n", delta);
725 return DCCP_SANE_RTT_MAX;
726 }
727
728 return delta;
729 }
730
731 EXPORT_SYMBOL_GPL(dccp_sample_rtt);
WRT350N Kernel Patches