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Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux/fpc-iii.git] / net / dccp / output.c
blob7102e3aed4ca2885928e990cf8b934e87d6fe2e4
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 skb->h.raw = skb_push(skb, dccp_header_size);
92 dh = dccp_hdr(skb);
93
94 /* Build DCCP header and checksum it. */
95 memset(dh, 0, dccp_header_size);
96 dh->dccph_type = dcb->dccpd_type;
97 dh->dccph_sport = inet->sport;
98 dh->dccph_dport = inet->dport;
99 dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
100 dh->dccph_ccval = dcb->dccpd_ccval;
101 /* XXX For now we're using only 48 bits sequence numbers */
102 dh->dccph_x = 1;
103
104 dp->dccps_awh = dp->dccps_gss;
105 dccp_hdr_set_seq(dh, dp->dccps_gss);
106 if (set_ack)
107 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
108
109 switch (dcb->dccpd_type) {
110 case DCCP_PKT_REQUEST:
111 dccp_hdr_request(skb)->dccph_req_service =
112 dp->dccps_service;
113 break;
114 case DCCP_PKT_RESET:
115 dccp_hdr_reset(skb)->dccph_reset_code =
116 dcb->dccpd_reset_code;
117 break;
118 }
119
120 icsk->icsk_af_ops->send_check(sk, skb->len, skb);
121
122 if (set_ack)
123 dccp_event_ack_sent(sk);
124
125 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
126
127 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
128 err = icsk->icsk_af_ops->queue_xmit(skb, 0);
129 if (err <= 0)
130 return err;
131
132 /* NET_XMIT_CN is special. It does not guarantee,
133 * that this packet is lost. It tells that device
134 * is about to start to drop packets or already
135 * drops some packets of the same priority and
136 * invokes us to send less aggressively.
137 */
138 return err == NET_XMIT_CN ? 0 : err;
139 }
140 return -ENOBUFS;
141 }
142
143 unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
144 {
145 struct inet_connection_sock *icsk = inet_csk(sk);
146 struct dccp_sock *dp = dccp_sk(sk);
147 int mss_now = (pmtu - icsk->icsk_af_ops->net_header_len -
148 sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext));
149
150 /* Now subtract optional transport overhead */
151 mss_now -= icsk->icsk_ext_hdr_len;
152
153 /*
154 * FIXME: this should come from the CCID infrastructure, where, say,
155 * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
156 * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
157 * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
158 * make it a multiple of 4
159 */
160
161 mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
162
163 /* And store cached results */
164 icsk->icsk_pmtu_cookie = pmtu;
165 dp->dccps_mss_cache = mss_now;
166
167 return mss_now;
168 }
169
170 EXPORT_SYMBOL_GPL(dccp_sync_mss);
171
172 void dccp_write_space(struct sock *sk)
173 {
174 read_lock(&sk->sk_callback_lock);
175
176 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
177 wake_up_interruptible(sk->sk_sleep);
178 /* Should agree with poll, otherwise some programs break */
179 if (sock_writeable(sk))
180 sk_wake_async(sk, 2, POLL_OUT);
181
182 read_unlock(&sk->sk_callback_lock);
183 }
184
185 /**
186 * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
187 * @sk: socket to wait for
188 * @timeo: for how long
189 */
190 static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
191 long *timeo)
192 {
193 struct dccp_sock *dp = dccp_sk(sk);
194 DEFINE_WAIT(wait);
195 long delay;
196 int rc;
197
198 while (1) {
199 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
200
201 if (sk->sk_err)
202 goto do_error;
203 if (!*timeo)
204 goto do_nonblock;
205 if (signal_pending(current))
206 goto do_interrupted;
207
208 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
209 skb->len);
210 if (rc <= 0)
211 break;
212 delay = msecs_to_jiffies(rc);
213 if (delay > *timeo || delay < 0)
214 goto do_nonblock;
215
216 sk->sk_write_pending++;
217 release_sock(sk);
218 *timeo -= schedule_timeout(delay);
219 lock_sock(sk);
220 sk->sk_write_pending--;
221 }
222 out:
223 finish_wait(sk->sk_sleep, &wait);
224 return rc;
225
226 do_error:
227 rc = -EPIPE;
228 goto out;
229 do_nonblock:
230 rc = -EAGAIN;
231 goto out;
232 do_interrupted:
233 rc = sock_intr_errno(*timeo);
234 goto out;
235 }
236
237 static void dccp_write_xmit_timer(unsigned long data) {
238 struct sock *sk = (struct sock *)data;
239 struct dccp_sock *dp = dccp_sk(sk);
240
241 bh_lock_sock(sk);
242 if (sock_owned_by_user(sk))
243 sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);
244 else
245 dccp_write_xmit(sk, 0);
246 bh_unlock_sock(sk);
247 sock_put(sk);
248 }
249
250 void dccp_write_xmit(struct sock *sk, int block)
251 {
252 struct dccp_sock *dp = dccp_sk(sk);
253 struct sk_buff *skb;
254 long timeo = 30000; /* If a packet is taking longer than 2 secs
255 we have other issues */
256
257 while ((skb = skb_peek(&sk->sk_write_queue))) {
258 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
259 skb->len);
260
261 if (err > 0) {
262 if (!block) {
263 sk_reset_timer(sk, &dp->dccps_xmit_timer,
264 msecs_to_jiffies(err)+jiffies);
265 break;
266 } else
267 err = dccp_wait_for_ccid(sk, skb, &timeo);
268 if (err) {
269 printk(KERN_CRIT "%s:err at dccp_wait_for_ccid"
270 " %d\n", __FUNCTION__, err);
271 dump_stack();
272 }
273 }
274
275 skb_dequeue(&sk->sk_write_queue);
276 if (err == 0) {
277 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
278 const int len = skb->len;
279
280 if (sk->sk_state == DCCP_PARTOPEN) {
281 /* See 8.1.5. Handshake Completion */
282 inet_csk_schedule_ack(sk);
283 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
284 inet_csk(sk)->icsk_rto,
285 DCCP_RTO_MAX);
286 dcb->dccpd_type = DCCP_PKT_DATAACK;
287 } else if (dccp_ack_pending(sk))
288 dcb->dccpd_type = DCCP_PKT_DATAACK;
289 else
290 dcb->dccpd_type = DCCP_PKT_DATA;
291
292 err = dccp_transmit_skb(sk, skb);
293 ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
294 if (err) {
295 printk(KERN_CRIT "%s:err from "
296 "ccid_hc_tx_packet_sent %d\n",
297 __FUNCTION__, err);
298 dump_stack();
299 }
300 } else
301 kfree(skb);
302 }
303 }
304
305 int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
306 {
307 if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
308 return -EHOSTUNREACH; /* Routing failure or similar. */
309
310 return dccp_transmit_skb(sk, (skb_cloned(skb) ?
311 pskb_copy(skb, GFP_ATOMIC):
312 skb_clone(skb, GFP_ATOMIC)));
313 }
314
315 struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
316 struct request_sock *req)
317 {
318 struct dccp_hdr *dh;
319 struct dccp_request_sock *dreq;
320 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
321 sizeof(struct dccp_hdr_ext) +
322 sizeof(struct dccp_hdr_response);
323 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
324 GFP_ATOMIC);
325 if (skb == NULL)
326 return NULL;
327
328 /* Reserve space for headers. */
329 skb_reserve(skb, sk->sk_prot->max_header);
330
331 skb->dst = dst_clone(dst);
332 skb->csum = 0;
333
334 dreq = dccp_rsk(req);
335 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
336 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
337
338 if (dccp_insert_options(sk, skb)) {
339 kfree_skb(skb);
340 return NULL;
341 }
342
343 skb->h.raw = skb_push(skb, dccp_header_size);
344
345 dh = dccp_hdr(skb);
346 memset(dh, 0, dccp_header_size);
347
348 dh->dccph_sport = inet_sk(sk)->sport;
349 dh->dccph_dport = inet_rsk(req)->rmt_port;
350 dh->dccph_doff = (dccp_header_size +
351 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
352 dh->dccph_type = DCCP_PKT_RESPONSE;
353 dh->dccph_x = 1;
354 dccp_hdr_set_seq(dh, dreq->dreq_iss);
355 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
356 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
357
358 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
359 return skb;
360 }
361
362 EXPORT_SYMBOL_GPL(dccp_make_response);
363
364 static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
365 const enum dccp_reset_codes code)
366
367 {
368 struct dccp_hdr *dh;
369 struct dccp_sock *dp = dccp_sk(sk);
370 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
371 sizeof(struct dccp_hdr_ext) +
372 sizeof(struct dccp_hdr_reset);
373 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
374 GFP_ATOMIC);
375 if (skb == NULL)
376 return NULL;
377
378 /* Reserve space for headers. */
379 skb_reserve(skb, sk->sk_prot->max_header);
380
381 skb->dst = dst_clone(dst);
382 skb->csum = 0;
383
384 dccp_inc_seqno(&dp->dccps_gss);
385
386 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
387 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
388 DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
389
390 if (dccp_insert_options(sk, skb)) {
391 kfree_skb(skb);
392 return NULL;
393 }
394
395 skb->h.raw = skb_push(skb, dccp_header_size);
396
397 dh = dccp_hdr(skb);
398 memset(dh, 0, dccp_header_size);
399
400 dh->dccph_sport = inet_sk(sk)->sport;
401 dh->dccph_dport = inet_sk(sk)->dport;
402 dh->dccph_doff = (dccp_header_size +
403 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
404 dh->dccph_type = DCCP_PKT_RESET;
405 dh->dccph_x = 1;
406 dccp_hdr_set_seq(dh, dp->dccps_gss);
407 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
408
409 dccp_hdr_reset(skb)->dccph_reset_code = code;
410 inet_csk(sk)->icsk_af_ops->send_check(sk, skb->len, skb);
411
412 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
413 return skb;
414 }
415
416 int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
417 {
418 /*
419 * FIXME: what if rebuild_header fails?
420 * Should we be doing a rebuild_header here?
421 */
422 int err = inet_sk_rebuild_header(sk);
423
424 if (err == 0) {
425 struct sk_buff *skb = dccp_make_reset(sk, sk->sk_dst_cache,
426 code);
427 if (skb != NULL) {
428 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
429 err = inet_csk(sk)->icsk_af_ops->queue_xmit(skb, 0);
430 if (err == NET_XMIT_CN)
431 err = 0;
432 }
433 }
434
435 return err;
436 }
437
438 /*
439 * Do all connect socket setups that can be done AF independent.
440 */
441 static inline void dccp_connect_init(struct sock *sk)
442 {
443 struct dccp_sock *dp = dccp_sk(sk);
444 struct dst_entry *dst = __sk_dst_get(sk);
445 struct inet_connection_sock *icsk = inet_csk(sk);
446
447 sk->sk_err = 0;
448 sock_reset_flag(sk, SOCK_DONE);
449
450 dccp_sync_mss(sk, dst_mtu(dst));
451
452 dccp_update_gss(sk, dp->dccps_iss);
453 /*
454 * SWL and AWL are initially adjusted so that they are not less than
455 * the initial Sequence Numbers received and sent, respectively:
456 * SWL := max(GSR + 1 - floor(W/4), ISR),
457 * AWL := max(GSS - W' + 1, ISS).
458 * These adjustments MUST be applied only at the beginning of the
459 * connection.
460 */
461 dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
462
463 icsk->icsk_retransmits = 0;
464 init_timer(&dp->dccps_xmit_timer);
465 dp->dccps_xmit_timer.data = (unsigned long)sk;
466 dp->dccps_xmit_timer.function = dccp_write_xmit_timer;
467 }
468
469 int dccp_connect(struct sock *sk)
470 {
471 struct sk_buff *skb;
472 struct inet_connection_sock *icsk = inet_csk(sk);
473
474 dccp_connect_init(sk);
475
476 skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
477 if (unlikely(skb == NULL))
478 return -ENOBUFS;
479
480 /* Reserve space for headers. */
481 skb_reserve(skb, sk->sk_prot->max_header);
482
483 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
484 skb->csum = 0;
485
486 dccp_skb_entail(sk, skb);
487 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
488 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
489
490 /* Timer for repeating the REQUEST until an answer. */
491 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
492 icsk->icsk_rto, DCCP_RTO_MAX);
493 return 0;
494 }
495
496 EXPORT_SYMBOL_GPL(dccp_connect);
497
498 void dccp_send_ack(struct sock *sk)
499 {
500 /* If we have been reset, we may not send again. */
501 if (sk->sk_state != DCCP_CLOSED) {
502 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
503 GFP_ATOMIC);
504
505 if (skb == NULL) {
506 inet_csk_schedule_ack(sk);
507 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
508 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
509 TCP_DELACK_MAX,
510 DCCP_RTO_MAX);
511 return;
512 }
513
514 /* Reserve space for headers */
515 skb_reserve(skb, sk->sk_prot->max_header);
516 skb->csum = 0;
517 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
518 dccp_transmit_skb(sk, skb);
519 }
520 }
521
522 EXPORT_SYMBOL_GPL(dccp_send_ack);
523
524 void dccp_send_delayed_ack(struct sock *sk)
525 {
526 struct inet_connection_sock *icsk = inet_csk(sk);
527 /*
528 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
529 * with using 2s, and active senders also piggyback the ACK into a
530 * DATAACK packet, so this is really for quiescent senders.
531 */
532 unsigned long timeout = jiffies + 2 * HZ;
533
534 /* Use new timeout only if there wasn't a older one earlier. */
535 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
536 /* If delack timer was blocked or is about to expire,
537 * send ACK now.
538 *
539 * FIXME: check the "about to expire" part
540 */
541 if (icsk->icsk_ack.blocked) {
542 dccp_send_ack(sk);
543 return;
544 }
545
546 if (!time_before(timeout, icsk->icsk_ack.timeout))
547 timeout = icsk->icsk_ack.timeout;
548 }
549 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
550 icsk->icsk_ack.timeout = timeout;
551 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
552 }
553
554 void dccp_send_sync(struct sock *sk, const u64 seq,
555 const enum dccp_pkt_type pkt_type)
556 {
557 /*
558 * We are not putting this on the write queue, so
559 * dccp_transmit_skb() will set the ownership to this
560 * sock.
561 */
562 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
563
564 if (skb == NULL)
565 /* FIXME: how to make sure the sync is sent? */
566 return;
567
568 /* Reserve space for headers and prepare control bits. */
569 skb_reserve(skb, sk->sk_prot->max_header);
570 skb->csum = 0;
571 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
572 DCCP_SKB_CB(skb)->dccpd_seq = seq;
573
574 dccp_transmit_skb(sk, skb);
575 }
576
577 EXPORT_SYMBOL_GPL(dccp_send_sync);
578
579 /*
580 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
581 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
582 * any circumstances.
583 */
584 void dccp_send_close(struct sock *sk, const int active)
585 {
586 struct dccp_sock *dp = dccp_sk(sk);
587 struct sk_buff *skb;
588 const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
589
590 skb = alloc_skb(sk->sk_prot->max_header, prio);
591 if (skb == NULL)
592 return;
593
594 /* Reserve space for headers and prepare control bits. */
595 skb_reserve(skb, sk->sk_prot->max_header);
596 skb->csum = 0;
597 DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
598 DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
599
600 if (active) {
601 dccp_write_xmit(sk, 1);
602 dccp_skb_entail(sk, skb);
603 dccp_transmit_skb(sk, skb_clone(skb, prio));
604 /* FIXME do we need a retransmit timer here? */
605 } else
606 dccp_transmit_skb(sk, skb);
607 }
Linux with added FPC-III support