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[DCCP] ccid3: Initialise RTT values
[deliverable/linux.git] / net / dccp / output.c
1 /*
2 * net/dccp/output.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/kernel.h>
15 #include <linux/skbuff.h>
16
17 #include <net/inet_sock.h>
18 #include <net/sock.h>
19
20 #include "ackvec.h"
21 #include "ccid.h"
22 #include "dccp.h"
23
24 static inline void dccp_event_ack_sent(struct sock *sk)
25 {
26 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
27 }
28
29 static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb)
30 {
31 skb_set_owner_w(skb, sk);
32 WARN_ON(sk->sk_send_head);
33 sk->sk_send_head = skb;
34 }
35
36 /*
37 * All SKB's seen here are completely headerless. It is our
38 * job to build the DCCP header, and pass the packet down to
39 * IP so it can do the same plus pass the packet off to the
40 * device.
41 */
42 static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
43 {
44 if (likely(skb != NULL)) {
45 const struct inet_sock *inet = inet_sk(sk);
46 const struct inet_connection_sock *icsk = inet_csk(sk);
47 struct dccp_sock *dp = dccp_sk(sk);
48 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
49 struct dccp_hdr *dh;
50 /* XXX For now we're using only 48 bits sequence numbers */
51 const u32 dccp_header_size = sizeof(*dh) +
52 sizeof(struct dccp_hdr_ext) +
53 dccp_packet_hdr_len(dcb->dccpd_type);
54 int err, set_ack = 1;
55 u64 ackno = dp->dccps_gsr;
56
57 dccp_inc_seqno(&dp->dccps_gss);
58
59 switch (dcb->dccpd_type) {
60 case DCCP_PKT_DATA:
61 set_ack = 0;
62 /* fall through */
63 case DCCP_PKT_DATAACK:
64 break;
65
66 case DCCP_PKT_REQUEST:
67 set_ack = 0;
68 /* fall through */
69
70 case DCCP_PKT_SYNC:
71 case DCCP_PKT_SYNCACK:
72 ackno = dcb->dccpd_seq;
73 /* fall through */
74 default:
75 /*
76 * Only data packets should come through with skb->sk
77 * set.
78 */
79 WARN_ON(skb->sk);
80 skb_set_owner_w(skb, sk);
81 break;
82 }
83
84 dcb->dccpd_seq = dp->dccps_gss;
85
86 if (dccp_insert_options(sk, skb)) {
87 kfree_skb(skb);
88 return -EPROTO;
89 }
90
91
92 /* Build DCCP header and checksum it. */
93 dh = dccp_zeroed_hdr(skb, dccp_header_size);
94 dh->dccph_type = dcb->dccpd_type;
95 dh->dccph_sport = inet->sport;
96 dh->dccph_dport = inet->dport;
97 dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
98 dh->dccph_ccval = dcb->dccpd_ccval;
99 dh->dccph_cscov = dp->dccps_pcslen;
100 /* XXX For now we're using only 48 bits sequence numbers */
101 dh->dccph_x = 1;
102
103 dp->dccps_awh = dp->dccps_gss;
104 dccp_hdr_set_seq(dh, dp->dccps_gss);
105 if (set_ack)
106 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
107
108 switch (dcb->dccpd_type) {
109 case DCCP_PKT_REQUEST:
110 dccp_hdr_request(skb)->dccph_req_service =
111 dp->dccps_service;
112 break;
113 case DCCP_PKT_RESET:
114 dccp_hdr_reset(skb)->dccph_reset_code =
115 dcb->dccpd_reset_code;
116 break;
117 }
118
119 icsk->icsk_af_ops->send_check(sk, 0, skb);
120
121 if (set_ack)
122 dccp_event_ack_sent(sk);
123
124 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
125
126 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
127 err = icsk->icsk_af_ops->queue_xmit(skb, sk, 0);
128 return net_xmit_eval(err);
129 }
130 return -ENOBUFS;
131 }
132
133 unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
134 {
135 struct inet_connection_sock *icsk = inet_csk(sk);
136 struct dccp_sock *dp = dccp_sk(sk);
137 int mss_now = (pmtu - icsk->icsk_af_ops->net_header_len -
138 sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext));
139
140 /* Now subtract optional transport overhead */
141 mss_now -= icsk->icsk_ext_hdr_len;
142
143 /*
144 * FIXME: this should come from the CCID infrastructure, where, say,
145 * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
146 * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
147 * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
148 * make it a multiple of 4
149 */
150
151 mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
152
153 /* And store cached results */
154 icsk->icsk_pmtu_cookie = pmtu;
155 dp->dccps_mss_cache = mss_now;
156
157 return mss_now;
158 }
159
160 EXPORT_SYMBOL_GPL(dccp_sync_mss);
161
162 void dccp_write_space(struct sock *sk)
163 {
164 read_lock(&sk->sk_callback_lock);
165
166 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
167 wake_up_interruptible(sk->sk_sleep);
168 /* Should agree with poll, otherwise some programs break */
169 if (sock_writeable(sk))
170 sk_wake_async(sk, 2, POLL_OUT);
171
172 read_unlock(&sk->sk_callback_lock);
173 }
174
175 /**
176 * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
177 * @sk: socket to wait for
178 */
179 static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb)
180 {
181 struct dccp_sock *dp = dccp_sk(sk);
182 DEFINE_WAIT(wait);
183 unsigned long delay;
184 int rc;
185
186 while (1) {
187 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
188
189 if (sk->sk_err)
190 goto do_error;
191 if (signal_pending(current))
192 goto do_interrupted;
193
194 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
195 if (rc <= 0)
196 break;
197 delay = msecs_to_jiffies(rc);
198 sk->sk_write_pending++;
199 release_sock(sk);
200 schedule_timeout(delay);
201 lock_sock(sk);
202 sk->sk_write_pending--;
203 }
204 out:
205 finish_wait(sk->sk_sleep, &wait);
206 return rc;
207
208 do_error:
209 rc = -EPIPE;
210 goto out;
211 do_interrupted:
212 rc = -EINTR;
213 goto out;
214 }
215
216 static void dccp_write_xmit_timer(unsigned long data) {
217 struct sock *sk = (struct sock *)data;
218 struct dccp_sock *dp = dccp_sk(sk);
219
220 bh_lock_sock(sk);
221 if (sock_owned_by_user(sk))
222 sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);
223 else
224 dccp_write_xmit(sk, 0);
225 bh_unlock_sock(sk);
226 sock_put(sk);
227 }
228
229 void dccp_write_xmit(struct sock *sk, int block)
230 {
231 struct dccp_sock *dp = dccp_sk(sk);
232 struct sk_buff *skb;
233
234 while ((skb = skb_peek(&sk->sk_write_queue))) {
235 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
236
237 if (err > 0) {
238 if (!block) {
239 sk_reset_timer(sk, &dp->dccps_xmit_timer,
240 msecs_to_jiffies(err)+jiffies);
241 break;
242 } else
243 err = dccp_wait_for_ccid(sk, skb);
244 if (err && err != -EINTR)
245 DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
246 }
247
248 skb_dequeue(&sk->sk_write_queue);
249 if (err == 0) {
250 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
251 const int len = skb->len;
252
253 if (sk->sk_state == DCCP_PARTOPEN) {
254 /* See 8.1.5. Handshake Completion */
255 inet_csk_schedule_ack(sk);
256 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
257 inet_csk(sk)->icsk_rto,
258 DCCP_RTO_MAX);
259 dcb->dccpd_type = DCCP_PKT_DATAACK;
260 } else if (dccp_ack_pending(sk))
261 dcb->dccpd_type = DCCP_PKT_DATAACK;
262 else
263 dcb->dccpd_type = DCCP_PKT_DATA;
264
265 err = dccp_transmit_skb(sk, skb);
266 ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
267 if (err)
268 DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
269 err);
270 } else {
271 dccp_pr_debug("packet discarded\n");
272 kfree(skb);
273 }
274 }
275 }
276
277 int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
278 {
279 if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
280 return -EHOSTUNREACH; /* Routing failure or similar. */
281
282 return dccp_transmit_skb(sk, (skb_cloned(skb) ?
283 pskb_copy(skb, GFP_ATOMIC):
284 skb_clone(skb, GFP_ATOMIC)));
285 }
286
287 struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
288 struct request_sock *req)
289 {
290 struct dccp_hdr *dh;
291 struct dccp_request_sock *dreq;
292 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
293 sizeof(struct dccp_hdr_ext) +
294 sizeof(struct dccp_hdr_response);
295 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
296 GFP_ATOMIC);
297 if (skb == NULL)
298 return NULL;
299
300 /* Reserve space for headers. */
301 skb_reserve(skb, sk->sk_prot->max_header);
302
303 skb->dst = dst_clone(dst);
304
305 dreq = dccp_rsk(req);
306 if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
307 dccp_inc_seqno(&dreq->dreq_iss);
308 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
309 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
310
311 if (dccp_insert_options(sk, skb)) {
312 kfree_skb(skb);
313 return NULL;
314 }
315
316 /* Build and checksum header */
317 dh = dccp_zeroed_hdr(skb, dccp_header_size);
318
319 dh->dccph_sport = inet_sk(sk)->sport;
320 dh->dccph_dport = inet_rsk(req)->rmt_port;
321 dh->dccph_doff = (dccp_header_size +
322 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
323 dh->dccph_type = DCCP_PKT_RESPONSE;
324 dh->dccph_x = 1;
325 dccp_hdr_set_seq(dh, dreq->dreq_iss);
326 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
327 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
328
329 dccp_csum_outgoing(skb);
330
331 /* We use `acked' to remember that a Response was already sent. */
332 inet_rsk(req)->acked = 1;
333 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
334 return skb;
335 }
336
337 EXPORT_SYMBOL_GPL(dccp_make_response);
338
339 static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
340 const enum dccp_reset_codes code)
341
342 {
343 struct dccp_hdr *dh;
344 struct dccp_sock *dp = dccp_sk(sk);
345 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
346 sizeof(struct dccp_hdr_ext) +
347 sizeof(struct dccp_hdr_reset);
348 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
349 GFP_ATOMIC);
350 if (skb == NULL)
351 return NULL;
352
353 /* Reserve space for headers. */
354 skb_reserve(skb, sk->sk_prot->max_header);
355
356 skb->dst = dst_clone(dst);
357
358 dccp_inc_seqno(&dp->dccps_gss);
359
360 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
361 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
362 DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
363
364 if (dccp_insert_options(sk, skb)) {
365 kfree_skb(skb);
366 return NULL;
367 }
368
369 dh = dccp_zeroed_hdr(skb, dccp_header_size);
370
371 dh->dccph_sport = inet_sk(sk)->sport;
372 dh->dccph_dport = inet_sk(sk)->dport;
373 dh->dccph_doff = (dccp_header_size +
374 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
375 dh->dccph_type = DCCP_PKT_RESET;
376 dh->dccph_x = 1;
377 dccp_hdr_set_seq(dh, dp->dccps_gss);
378 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
379
380 dccp_hdr_reset(skb)->dccph_reset_code = code;
381 inet_csk(sk)->icsk_af_ops->send_check(sk, 0, skb);
382
383 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
384 return skb;
385 }
386
387 int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
388 {
389 /*
390 * FIXME: what if rebuild_header fails?
391 * Should we be doing a rebuild_header here?
392 */
393 int err = inet_sk_rebuild_header(sk);
394
395 if (err == 0) {
396 struct sk_buff *skb = dccp_make_reset(sk, sk->sk_dst_cache,
397 code);
398 if (skb != NULL) {
399 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
400 err = inet_csk(sk)->icsk_af_ops->queue_xmit(skb, sk, 0);
401 return net_xmit_eval(err);
402 }
403 }
404
405 return err;
406 }
407
408 /*
409 * Do all connect socket setups that can be done AF independent.
410 */
411 static inline void dccp_connect_init(struct sock *sk)
412 {
413 struct dccp_sock *dp = dccp_sk(sk);
414 struct dst_entry *dst = __sk_dst_get(sk);
415 struct inet_connection_sock *icsk = inet_csk(sk);
416
417 sk->sk_err = 0;
418 sock_reset_flag(sk, SOCK_DONE);
419
420 dccp_sync_mss(sk, dst_mtu(dst));
421
422 /*
423 * SWL and AWL are initially adjusted so that they are not less than
424 * the initial Sequence Numbers received and sent, respectively:
425 * SWL := max(GSR + 1 - floor(W/4), ISR),
426 * AWL := max(GSS - W' + 1, ISS).
427 * These adjustments MUST be applied only at the beginning of the
428 * connection.
429 */
430 dccp_update_gss(sk, dp->dccps_iss);
431 dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
432
433 /* S.GAR - greatest valid acknowledgement number received on a non-Sync;
434 * initialized to S.ISS (sec. 8.5) */
435 dp->dccps_gar = dp->dccps_iss;
436
437 icsk->icsk_retransmits = 0;
438 init_timer(&dp->dccps_xmit_timer);
439 dp->dccps_xmit_timer.data = (unsigned long)sk;
440 dp->dccps_xmit_timer.function = dccp_write_xmit_timer;
441 }
442
443 int dccp_connect(struct sock *sk)
444 {
445 struct sk_buff *skb;
446 struct inet_connection_sock *icsk = inet_csk(sk);
447
448 dccp_connect_init(sk);
449
450 skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
451 if (unlikely(skb == NULL))
452 return -ENOBUFS;
453
454 /* Reserve space for headers. */
455 skb_reserve(skb, sk->sk_prot->max_header);
456
457 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
458
459 dccp_skb_entail(sk, skb);
460 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
461 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
462
463 /* Timer for repeating the REQUEST until an answer. */
464 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
465 icsk->icsk_rto, DCCP_RTO_MAX);
466 return 0;
467 }
468
469 EXPORT_SYMBOL_GPL(dccp_connect);
470
471 void dccp_send_ack(struct sock *sk)
472 {
473 /* If we have been reset, we may not send again. */
474 if (sk->sk_state != DCCP_CLOSED) {
475 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
476 GFP_ATOMIC);
477
478 if (skb == NULL) {
479 inet_csk_schedule_ack(sk);
480 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
481 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
482 TCP_DELACK_MAX,
483 DCCP_RTO_MAX);
484 return;
485 }
486
487 /* Reserve space for headers */
488 skb_reserve(skb, sk->sk_prot->max_header);
489 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
490 dccp_transmit_skb(sk, skb);
491 }
492 }
493
494 EXPORT_SYMBOL_GPL(dccp_send_ack);
495
496 void dccp_send_delayed_ack(struct sock *sk)
497 {
498 struct inet_connection_sock *icsk = inet_csk(sk);
499 /*
500 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
501 * with using 2s, and active senders also piggyback the ACK into a
502 * DATAACK packet, so this is really for quiescent senders.
503 */
504 unsigned long timeout = jiffies + 2 * HZ;
505
506 /* Use new timeout only if there wasn't a older one earlier. */
507 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
508 /* If delack timer was blocked or is about to expire,
509 * send ACK now.
510 *
511 * FIXME: check the "about to expire" part
512 */
513 if (icsk->icsk_ack.blocked) {
514 dccp_send_ack(sk);
515 return;
516 }
517
518 if (!time_before(timeout, icsk->icsk_ack.timeout))
519 timeout = icsk->icsk_ack.timeout;
520 }
521 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
522 icsk->icsk_ack.timeout = timeout;
523 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
524 }
525
526 void dccp_send_sync(struct sock *sk, const u64 seq,
527 const enum dccp_pkt_type pkt_type)
528 {
529 /*
530 * We are not putting this on the write queue, so
531 * dccp_transmit_skb() will set the ownership to this
532 * sock.
533 */
534 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
535
536 if (skb == NULL)
537 /* FIXME: how to make sure the sync is sent? */
538 return;
539
540 /* Reserve space for headers and prepare control bits. */
541 skb_reserve(skb, sk->sk_prot->max_header);
542 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
543 DCCP_SKB_CB(skb)->dccpd_seq = seq;
544
545 dccp_transmit_skb(sk, skb);
546 }
547
548 EXPORT_SYMBOL_GPL(dccp_send_sync);
549
550 /*
551 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
552 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
553 * any circumstances.
554 */
555 void dccp_send_close(struct sock *sk, const int active)
556 {
557 struct dccp_sock *dp = dccp_sk(sk);
558 struct sk_buff *skb;
559 const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
560
561 skb = alloc_skb(sk->sk_prot->max_header, prio);
562 if (skb == NULL)
563 return;
564
565 /* Reserve space for headers and prepare control bits. */
566 skb_reserve(skb, sk->sk_prot->max_header);
567 DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
568 DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
569
570 if (active) {
571 dccp_write_xmit(sk, 1);
572 dccp_skb_entail(sk, skb);
573 dccp_transmit_skb(sk, skb_clone(skb, prio));
574 /* FIXME do we need a retransmit timer here? */
575 } else
576 dccp_transmit_skb(sk, skb);
577 }
Linux kernel - Deliverables
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