Merge tag 'usb-3.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / dccp / input.c
blob51d5fe5fffba6bba0592dd147b8693726a5afc05
1 /*
2 * net/dccp/input.c
4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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.
13 #include <linux/dccp.h>
14 #include <linux/skbuff.h>
15 #include <linux/slab.h>
17 #include <net/sock.h>
19 #include "ackvec.h"
20 #include "ccid.h"
21 #include "dccp.h"
23 /* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */
24 int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8;
26 static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb)
28 __skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
29 __skb_queue_tail(&sk->sk_receive_queue, skb);
30 skb_set_owner_r(skb, sk);
31 sk->sk_data_ready(sk, 0);
34 static void dccp_fin(struct sock *sk, struct sk_buff *skb)
37 * On receiving Close/CloseReq, both RD/WR shutdown are performed.
38 * RFC 4340, 8.3 says that we MAY send further Data/DataAcks after
39 * receiving the closing segment, but there is no guarantee that such
40 * data will be processed at all.
42 sk->sk_shutdown = SHUTDOWN_MASK;
43 sock_set_flag(sk, SOCK_DONE);
44 dccp_enqueue_skb(sk, skb);
47 static int dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
49 int queued = 0;
51 switch (sk->sk_state) {
53 * We ignore Close when received in one of the following states:
54 * - CLOSED (may be a late or duplicate packet)
55 * - PASSIVE_CLOSEREQ (the peer has sent a CloseReq earlier)
56 * - RESPOND (already handled by dccp_check_req)
58 case DCCP_CLOSING:
60 * Simultaneous-close: receiving a Close after sending one. This
61 * can happen if both client and server perform active-close and
62 * will result in an endless ping-pong of crossing and retrans-
63 * mitted Close packets, which only terminates when one of the
64 * nodes times out (min. 64 seconds). Quicker convergence can be
65 * achieved when one of the nodes acts as tie-breaker.
66 * This is ok as both ends are done with data transfer and each
67 * end is just waiting for the other to acknowledge termination.
69 if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT)
70 break;
71 /* fall through */
72 case DCCP_REQUESTING:
73 case DCCP_ACTIVE_CLOSEREQ:
74 dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
75 dccp_done(sk);
76 break;
77 case DCCP_OPEN:
78 case DCCP_PARTOPEN:
79 /* Give waiting application a chance to read pending data */
80 queued = 1;
81 dccp_fin(sk, skb);
82 dccp_set_state(sk, DCCP_PASSIVE_CLOSE);
83 /* fall through */
84 case DCCP_PASSIVE_CLOSE:
86 * Retransmitted Close: we have already enqueued the first one.
88 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
90 return queued;
93 static int dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
95 int queued = 0;
98 * Step 7: Check for unexpected packet types
99 * If (S.is_server and P.type == CloseReq)
100 * Send Sync packet acknowledging P.seqno
101 * Drop packet and return
103 if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
104 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
105 return queued;
108 /* Step 13: process relevant Client states < CLOSEREQ */
109 switch (sk->sk_state) {
110 case DCCP_REQUESTING:
111 dccp_send_close(sk, 0);
112 dccp_set_state(sk, DCCP_CLOSING);
113 break;
114 case DCCP_OPEN:
115 case DCCP_PARTOPEN:
116 /* Give waiting application a chance to read pending data */
117 queued = 1;
118 dccp_fin(sk, skb);
119 dccp_set_state(sk, DCCP_PASSIVE_CLOSEREQ);
120 /* fall through */
121 case DCCP_PASSIVE_CLOSEREQ:
122 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
124 return queued;
127 static u16 dccp_reset_code_convert(const u8 code)
129 const u16 error_code[] = {
130 [DCCP_RESET_CODE_CLOSED] = 0, /* normal termination */
131 [DCCP_RESET_CODE_UNSPECIFIED] = 0, /* nothing known */
132 [DCCP_RESET_CODE_ABORTED] = ECONNRESET,
134 [DCCP_RESET_CODE_NO_CONNECTION] = ECONNREFUSED,
135 [DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED,
136 [DCCP_RESET_CODE_TOO_BUSY] = EUSERS,
137 [DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT,
139 [DCCP_RESET_CODE_PACKET_ERROR] = ENOMSG,
140 [DCCP_RESET_CODE_BAD_INIT_COOKIE] = EBADR,
141 [DCCP_RESET_CODE_BAD_SERVICE_CODE] = EBADRQC,
142 [DCCP_RESET_CODE_OPTION_ERROR] = EILSEQ,
143 [DCCP_RESET_CODE_MANDATORY_ERROR] = EOPNOTSUPP,
146 return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code];
149 static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb)
151 u16 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code);
153 sk->sk_err = err;
155 /* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */
156 dccp_fin(sk, skb);
158 if (err && !sock_flag(sk, SOCK_DEAD))
159 sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
160 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
163 static void dccp_handle_ackvec_processing(struct sock *sk, struct sk_buff *skb)
165 struct dccp_ackvec *av = dccp_sk(sk)->dccps_hc_rx_ackvec;
167 if (av == NULL)
168 return;
169 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
170 dccp_ackvec_clear_state(av, DCCP_SKB_CB(skb)->dccpd_ack_seq);
171 dccp_ackvec_input(av, skb);
174 static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb)
176 const struct dccp_sock *dp = dccp_sk(sk);
178 /* Don't deliver to RX CCID when node has shut down read end. */
179 if (!(sk->sk_shutdown & RCV_SHUTDOWN))
180 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
182 * Until the TX queue has been drained, we can not honour SHUT_WR, since
183 * we need received feedback as input to adjust congestion control.
185 if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN))
186 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
189 static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
191 const struct dccp_hdr *dh = dccp_hdr(skb);
192 struct dccp_sock *dp = dccp_sk(sk);
193 u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq,
194 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
197 * Step 5: Prepare sequence numbers for Sync
198 * If P.type == Sync or P.type == SyncAck,
199 * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
200 * / * P is valid, so update sequence number variables
201 * accordingly. After this update, P will pass the tests
202 * in Step 6. A SyncAck is generated if necessary in
203 * Step 15 * /
204 * Update S.GSR, S.SWL, S.SWH
205 * Otherwise,
206 * Drop packet and return
208 if (dh->dccph_type == DCCP_PKT_SYNC ||
209 dh->dccph_type == DCCP_PKT_SYNCACK) {
210 if (between48(ackno, dp->dccps_awl, dp->dccps_awh) &&
211 dccp_delta_seqno(dp->dccps_swl, seqno) >= 0)
212 dccp_update_gsr(sk, seqno);
213 else
214 return -1;
218 * Step 6: Check sequence numbers
219 * Let LSWL = S.SWL and LAWL = S.AWL
220 * If P.type == CloseReq or P.type == Close or P.type == Reset,
221 * LSWL := S.GSR + 1, LAWL := S.GAR
222 * If LSWL <= P.seqno <= S.SWH
223 * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
224 * Update S.GSR, S.SWL, S.SWH
225 * If P.type != Sync,
226 * Update S.GAR
228 lswl = dp->dccps_swl;
229 lawl = dp->dccps_awl;
231 if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
232 dh->dccph_type == DCCP_PKT_CLOSE ||
233 dh->dccph_type == DCCP_PKT_RESET) {
234 lswl = ADD48(dp->dccps_gsr, 1);
235 lawl = dp->dccps_gar;
238 if (between48(seqno, lswl, dp->dccps_swh) &&
239 (ackno == DCCP_PKT_WITHOUT_ACK_SEQ ||
240 between48(ackno, lawl, dp->dccps_awh))) {
241 dccp_update_gsr(sk, seqno);
243 if (dh->dccph_type != DCCP_PKT_SYNC &&
244 ackno != DCCP_PKT_WITHOUT_ACK_SEQ &&
245 after48(ackno, dp->dccps_gar))
246 dp->dccps_gar = ackno;
247 } else {
248 unsigned long now = jiffies;
250 * Step 6: Check sequence numbers
251 * Otherwise,
252 * If P.type == Reset,
253 * Send Sync packet acknowledging S.GSR
254 * Otherwise,
255 * Send Sync packet acknowledging P.seqno
256 * Drop packet and return
258 * These Syncs are rate-limited as per RFC 4340, 7.5.4:
259 * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second.
261 if (time_before(now, (dp->dccps_rate_last +
262 sysctl_dccp_sync_ratelimit)))
263 return -1;
265 DCCP_WARN("Step 6 failed for %s packet, "
266 "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
267 "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
268 "sending SYNC...\n", dccp_packet_name(dh->dccph_type),
269 (unsigned long long) lswl, (unsigned long long) seqno,
270 (unsigned long long) dp->dccps_swh,
271 (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist"
272 : "exists",
273 (unsigned long long) lawl, (unsigned long long) ackno,
274 (unsigned long long) dp->dccps_awh);
276 dp->dccps_rate_last = now;
278 if (dh->dccph_type == DCCP_PKT_RESET)
279 seqno = dp->dccps_gsr;
280 dccp_send_sync(sk, seqno, DCCP_PKT_SYNC);
281 return -1;
284 return 0;
287 static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
288 const struct dccp_hdr *dh, const unsigned len)
290 struct dccp_sock *dp = dccp_sk(sk);
292 switch (dccp_hdr(skb)->dccph_type) {
293 case DCCP_PKT_DATAACK:
294 case DCCP_PKT_DATA:
296 * FIXME: schedule DATA_DROPPED (RFC 4340, 11.7.2) if and when
297 * - sk_shutdown == RCV_SHUTDOWN, use Code 1, "Not Listening"
298 * - sk_receive_queue is full, use Code 2, "Receive Buffer"
300 dccp_enqueue_skb(sk, skb);
301 return 0;
302 case DCCP_PKT_ACK:
303 goto discard;
304 case DCCP_PKT_RESET:
306 * Step 9: Process Reset
307 * If P.type == Reset,
308 * Tear down connection
309 * S.state := TIMEWAIT
310 * Set TIMEWAIT timer
311 * Drop packet and return
313 dccp_rcv_reset(sk, skb);
314 return 0;
315 case DCCP_PKT_CLOSEREQ:
316 if (dccp_rcv_closereq(sk, skb))
317 return 0;
318 goto discard;
319 case DCCP_PKT_CLOSE:
320 if (dccp_rcv_close(sk, skb))
321 return 0;
322 goto discard;
323 case DCCP_PKT_REQUEST:
324 /* Step 7
325 * or (S.is_server and P.type == Response)
326 * or (S.is_client and P.type == Request)
327 * or (S.state >= OPEN and P.type == Request
328 * and P.seqno >= S.OSR)
329 * or (S.state >= OPEN and P.type == Response
330 * and P.seqno >= S.OSR)
331 * or (S.state == RESPOND and P.type == Data),
332 * Send Sync packet acknowledging P.seqno
333 * Drop packet and return
335 if (dp->dccps_role != DCCP_ROLE_LISTEN)
336 goto send_sync;
337 goto check_seq;
338 case DCCP_PKT_RESPONSE:
339 if (dp->dccps_role != DCCP_ROLE_CLIENT)
340 goto send_sync;
341 check_seq:
342 if (dccp_delta_seqno(dp->dccps_osr,
343 DCCP_SKB_CB(skb)->dccpd_seq) >= 0) {
344 send_sync:
345 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
346 DCCP_PKT_SYNC);
348 break;
349 case DCCP_PKT_SYNC:
350 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
351 DCCP_PKT_SYNCACK);
353 * From RFC 4340, sec. 5.7
355 * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
356 * MAY have non-zero-length application data areas, whose
357 * contents receivers MUST ignore.
359 goto discard;
362 DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
363 discard:
364 __kfree_skb(skb);
365 return 0;
368 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
369 const struct dccp_hdr *dh, const unsigned len)
371 if (dccp_check_seqno(sk, skb))
372 goto discard;
374 if (dccp_parse_options(sk, NULL, skb))
375 return 1;
377 dccp_handle_ackvec_processing(sk, skb);
378 dccp_deliver_input_to_ccids(sk, skb);
380 return __dccp_rcv_established(sk, skb, dh, len);
381 discard:
382 __kfree_skb(skb);
383 return 0;
386 EXPORT_SYMBOL_GPL(dccp_rcv_established);
388 static int dccp_rcv_request_sent_state_process(struct sock *sk,
389 struct sk_buff *skb,
390 const struct dccp_hdr *dh,
391 const unsigned len)
394 * Step 4: Prepare sequence numbers in REQUEST
395 * If S.state == REQUEST,
396 * If (P.type == Response or P.type == Reset)
397 * and S.AWL <= P.ackno <= S.AWH,
398 * / * Set sequence number variables corresponding to the
399 * other endpoint, so P will pass the tests in Step 6 * /
400 * Set S.GSR, S.ISR, S.SWL, S.SWH
401 * / * Response processing continues in Step 10; Reset
402 * processing continues in Step 9 * /
404 if (dh->dccph_type == DCCP_PKT_RESPONSE) {
405 const struct inet_connection_sock *icsk = inet_csk(sk);
406 struct dccp_sock *dp = dccp_sk(sk);
407 long tstamp = dccp_timestamp();
409 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
410 dp->dccps_awl, dp->dccps_awh)) {
411 dccp_pr_debug("invalid ackno: S.AWL=%llu, "
412 "P.ackno=%llu, S.AWH=%llu\n",
413 (unsigned long long)dp->dccps_awl,
414 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
415 (unsigned long long)dp->dccps_awh);
416 goto out_invalid_packet;
420 * If option processing (Step 8) failed, return 1 here so that
421 * dccp_v4_do_rcv() sends a Reset. The Reset code depends on
422 * the option type and is set in dccp_parse_options().
424 if (dccp_parse_options(sk, NULL, skb))
425 return 1;
427 /* Obtain usec RTT sample from SYN exchange (used by TFRC). */
428 if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
429 dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp -
430 dp->dccps_options_received.dccpor_timestamp_echo));
432 /* Stop the REQUEST timer */
433 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
434 WARN_ON(sk->sk_send_head == NULL);
435 kfree_skb(sk->sk_send_head);
436 sk->sk_send_head = NULL;
439 * Set ISR, GSR from packet. ISS was set in dccp_v{4,6}_connect
440 * and GSS in dccp_transmit_skb(). Setting AWL/AWH and SWL/SWH
441 * is done as part of activating the feature values below, since
442 * these settings depend on the local/remote Sequence Window
443 * features, which were undefined or not confirmed until now.
445 dp->dccps_gsr = dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
447 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
450 * Step 10: Process REQUEST state (second part)
451 * If S.state == REQUEST,
452 * / * If we get here, P is a valid Response from the
453 * server (see Step 4), and we should move to
454 * PARTOPEN state. PARTOPEN means send an Ack,
455 * don't send Data packets, retransmit Acks
456 * periodically, and always include any Init Cookie
457 * from the Response * /
458 * S.state := PARTOPEN
459 * Set PARTOPEN timer
460 * Continue with S.state == PARTOPEN
461 * / * Step 12 will send the Ack completing the
462 * three-way handshake * /
464 dccp_set_state(sk, DCCP_PARTOPEN);
467 * If feature negotiation was successful, activate features now;
468 * an activation failure means that this host could not activate
469 * one ore more features (e.g. insufficient memory), which would
470 * leave at least one feature in an undefined state.
472 if (dccp_feat_activate_values(sk, &dp->dccps_featneg))
473 goto unable_to_proceed;
475 /* Make sure socket is routed, for correct metrics. */
476 icsk->icsk_af_ops->rebuild_header(sk);
478 if (!sock_flag(sk, SOCK_DEAD)) {
479 sk->sk_state_change(sk);
480 sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
483 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
484 icsk->icsk_accept_queue.rskq_defer_accept) {
485 /* Save one ACK. Data will be ready after
486 * several ticks, if write_pending is set.
488 * It may be deleted, but with this feature tcpdumps
489 * look so _wonderfully_ clever, that I was not able
490 * to stand against the temptation 8) --ANK
493 * OK, in DCCP we can as well do a similar trick, its
494 * even in the draft, but there is no need for us to
495 * schedule an ack here, as dccp_sendmsg does this for
496 * us, also stated in the draft. -acme
498 __kfree_skb(skb);
499 return 0;
501 dccp_send_ack(sk);
502 return -1;
505 out_invalid_packet:
506 /* dccp_v4_do_rcv will send a reset */
507 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
508 return 1;
510 unable_to_proceed:
511 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_ABORTED;
513 * We mark this socket as no longer usable, so that the loop in
514 * dccp_sendmsg() terminates and the application gets notified.
516 dccp_set_state(sk, DCCP_CLOSED);
517 sk->sk_err = ECOMM;
518 return 1;
521 static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
522 struct sk_buff *skb,
523 const struct dccp_hdr *dh,
524 const unsigned len)
526 struct dccp_sock *dp = dccp_sk(sk);
527 u32 sample = dp->dccps_options_received.dccpor_timestamp_echo;
528 int queued = 0;
530 switch (dh->dccph_type) {
531 case DCCP_PKT_RESET:
532 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
533 break;
534 case DCCP_PKT_DATA:
535 if (sk->sk_state == DCCP_RESPOND)
536 break;
537 case DCCP_PKT_DATAACK:
538 case DCCP_PKT_ACK:
540 * FIXME: we should be reseting the PARTOPEN (DELACK) timer
541 * here but only if we haven't used the DELACK timer for
542 * something else, like sending a delayed ack for a TIMESTAMP
543 * echo, etc, for now were not clearing it, sending an extra
544 * ACK when there is nothing else to do in DELACK is not a big
545 * deal after all.
548 /* Stop the PARTOPEN timer */
549 if (sk->sk_state == DCCP_PARTOPEN)
550 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
552 /* Obtain usec RTT sample from SYN exchange (used by TFRC). */
553 if (likely(sample)) {
554 long delta = dccp_timestamp() - sample;
556 dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * delta);
559 dp->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
560 dccp_set_state(sk, DCCP_OPEN);
562 if (dh->dccph_type == DCCP_PKT_DATAACK ||
563 dh->dccph_type == DCCP_PKT_DATA) {
564 __dccp_rcv_established(sk, skb, dh, len);
565 queued = 1; /* packet was queued
566 (by __dccp_rcv_established) */
568 break;
571 return queued;
574 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
575 struct dccp_hdr *dh, unsigned len)
577 struct dccp_sock *dp = dccp_sk(sk);
578 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
579 const int old_state = sk->sk_state;
580 int queued = 0;
583 * Step 3: Process LISTEN state
585 * If S.state == LISTEN,
586 * If P.type == Request or P contains a valid Init Cookie option,
587 * (* Must scan the packet's options to check for Init
588 * Cookies. Only Init Cookies are processed here,
589 * however; other options are processed in Step 8. This
590 * scan need only be performed if the endpoint uses Init
591 * Cookies *)
592 * (* Generate a new socket and switch to that socket *)
593 * Set S := new socket for this port pair
594 * S.state = RESPOND
595 * Choose S.ISS (initial seqno) or set from Init Cookies
596 * Initialize S.GAR := S.ISS
597 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
598 * Cookies Continue with S.state == RESPOND
599 * (* A Response packet will be generated in Step 11 *)
600 * Otherwise,
601 * Generate Reset(No Connection) unless P.type == Reset
602 * Drop packet and return
604 if (sk->sk_state == DCCP_LISTEN) {
605 if (dh->dccph_type == DCCP_PKT_REQUEST) {
606 if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
607 skb) < 0)
608 return 1;
609 goto discard;
611 if (dh->dccph_type == DCCP_PKT_RESET)
612 goto discard;
614 /* Caller (dccp_v4_do_rcv) will send Reset */
615 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
616 return 1;
617 } else if (sk->sk_state == DCCP_CLOSED) {
618 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
619 return 1;
622 /* Step 6: Check sequence numbers (omitted in LISTEN/REQUEST state) */
623 if (sk->sk_state != DCCP_REQUESTING && dccp_check_seqno(sk, skb))
624 goto discard;
627 * Step 7: Check for unexpected packet types
628 * If (S.is_server and P.type == Response)
629 * or (S.is_client and P.type == Request)
630 * or (S.state == RESPOND and P.type == Data),
631 * Send Sync packet acknowledging P.seqno
632 * Drop packet and return
634 if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
635 dh->dccph_type == DCCP_PKT_RESPONSE) ||
636 (dp->dccps_role == DCCP_ROLE_CLIENT &&
637 dh->dccph_type == DCCP_PKT_REQUEST) ||
638 (sk->sk_state == DCCP_RESPOND && dh->dccph_type == DCCP_PKT_DATA)) {
639 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
640 goto discard;
643 /* Step 8: Process options */
644 if (dccp_parse_options(sk, NULL, skb))
645 return 1;
648 * Step 9: Process Reset
649 * If P.type == Reset,
650 * Tear down connection
651 * S.state := TIMEWAIT
652 * Set TIMEWAIT timer
653 * Drop packet and return
655 if (dh->dccph_type == DCCP_PKT_RESET) {
656 dccp_rcv_reset(sk, skb);
657 return 0;
658 } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { /* Step 13 */
659 if (dccp_rcv_closereq(sk, skb))
660 return 0;
661 goto discard;
662 } else if (dh->dccph_type == DCCP_PKT_CLOSE) { /* Step 14 */
663 if (dccp_rcv_close(sk, skb))
664 return 0;
665 goto discard;
668 switch (sk->sk_state) {
669 case DCCP_REQUESTING:
670 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
671 if (queued >= 0)
672 return queued;
674 __kfree_skb(skb);
675 return 0;
677 case DCCP_PARTOPEN:
678 /* Step 8: if using Ack Vectors, mark packet acknowledgeable */
679 dccp_handle_ackvec_processing(sk, skb);
680 dccp_deliver_input_to_ccids(sk, skb);
681 /* fall through */
682 case DCCP_RESPOND:
683 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
684 dh, len);
685 break;
688 if (dh->dccph_type == DCCP_PKT_ACK ||
689 dh->dccph_type == DCCP_PKT_DATAACK) {
690 switch (old_state) {
691 case DCCP_PARTOPEN:
692 sk->sk_state_change(sk);
693 sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
694 break;
696 } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
697 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
698 goto discard;
701 if (!queued) {
702 discard:
703 __kfree_skb(skb);
705 return 0;
708 EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
711 * dccp_sample_rtt - Validate and finalise computation of RTT sample
712 * @delta: number of microseconds between packet and acknowledgment
713 * The routine is kept generic to work in different contexts. It should be
714 * called immediately when the ACK used for the RTT sample arrives.
716 u32 dccp_sample_rtt(struct sock *sk, long delta)
718 /* dccpor_elapsed_time is either zeroed out or set and > 0 */
719 delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10;
721 if (unlikely(delta <= 0)) {
722 DCCP_WARN("unusable RTT sample %ld, using min\n", delta);
723 return DCCP_SANE_RTT_MIN;
725 if (unlikely(delta > DCCP_SANE_RTT_MAX)) {
726 DCCP_WARN("RTT sample %ld too large, using max\n", delta);
727 return DCCP_SANE_RTT_MAX;
730 return delta;