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[DCCP]: Introduce dccp_ipv4_af_ops
[linux-2.6.git] / net / dccp / output.c
blobf35880503bb8910ec6509349de57f8581ad80cd4
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/config.h>
14 #include <linux/dccp.h>
15 #include <linux/kernel.h>
16 #include <linux/skbuff.h>
17
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 inline 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 int 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_SYNC:
67 case DCCP_PKT_SYNCACK:
68 ackno = dcb->dccpd_seq;
69 /* fall through */
70 default:
71 /*
72 * Only data packets should come through with skb->sk
73 * set.
74 */
75 WARN_ON(skb->sk);
76 skb_set_owner_w(skb, sk);
77 break;
78 }
79
80 dcb->dccpd_seq = dp->dccps_gss;
81 dccp_insert_options(sk, skb);
82
83 skb->h.raw = skb_push(skb, dccp_header_size);
84 dh = dccp_hdr(skb);
85
86 /* Build DCCP header and checksum it. */
87 memset(dh, 0, dccp_header_size);
88 dh->dccph_type = dcb->dccpd_type;
89 dh->dccph_sport = inet->sport;
90 dh->dccph_dport = inet->dport;
91 dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
92 dh->dccph_ccval = dcb->dccpd_ccval;
93 /* XXX For now we're using only 48 bits sequence numbers */
94 dh->dccph_x = 1;
95
96 dp->dccps_awh = dp->dccps_gss;
97 dccp_hdr_set_seq(dh, dp->dccps_gss);
98 if (set_ack)
99 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
100
101 switch (dcb->dccpd_type) {
102 case DCCP_PKT_REQUEST:
103 dccp_hdr_request(skb)->dccph_req_service =
104 dp->dccps_service;
105 break;
106 case DCCP_PKT_RESET:
107 dccp_hdr_reset(skb)->dccph_reset_code =
108 dcb->dccpd_reset_code;
109 break;
110 }
111
112 icsk->icsk_af_ops->send_check(sk, skb->len, skb);
113
114 if (set_ack)
115 dccp_event_ack_sent(sk);
116
117 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
118
119 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
120 err = icsk->icsk_af_ops->queue_xmit(skb, 0);
121 if (err <= 0)
122 return err;
123
124 /* NET_XMIT_CN is special. It does not guarantee,
125 * that this packet is lost. It tells that device
126 * is about to start to drop packets or already
127 * drops some packets of the same priority and
128 * invokes us to send less aggressively.
129 */
130 return err == NET_XMIT_CN ? 0 : err;
131 }
132 return -ENOBUFS;
133 }
134
135 unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
136 {
137 struct dccp_sock *dp = dccp_sk(sk);
138 /*
139 * FIXME: we really should be using the af_specific thing to support
140 * IPv6.
141 * mss_now = pmtu - tp->af_specific->net_header_len -
142 * sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext);
143 */
144 int mss_now = (pmtu - inet_csk(sk)->icsk_af_ops->net_header_len -
145 sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext));
146
147 /* Now subtract optional transport overhead */
148 mss_now -= dp->dccps_ext_header_len;
149
150 /*
151 * FIXME: this should come from the CCID infrastructure, where, say,
152 * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
153 * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
154 * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
155 * make it a multiple of 4
156 */
157
158 mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
159
160 /* And store cached results */
161 dp->dccps_pmtu_cookie = pmtu;
162 dp->dccps_mss_cache = mss_now;
163
164 return mss_now;
165 }
166
167 void dccp_write_space(struct sock *sk)
168 {
169 read_lock(&sk->sk_callback_lock);
170
171 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
172 wake_up_interruptible(sk->sk_sleep);
173 /* Should agree with poll, otherwise some programs break */
174 if (sock_writeable(sk))
175 sk_wake_async(sk, 2, POLL_OUT);
176
177 read_unlock(&sk->sk_callback_lock);
178 }
179
180 /**
181 * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
182 * @sk: socket to wait for
183 * @timeo: for how long
184 */
185 static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
186 long *timeo)
187 {
188 struct dccp_sock *dp = dccp_sk(sk);
189 DEFINE_WAIT(wait);
190 long delay;
191 int rc;
192
193 while (1) {
194 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
195
196 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
197 goto do_error;
198 if (!*timeo)
199 goto do_nonblock;
200 if (signal_pending(current))
201 goto do_interrupted;
202
203 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
204 skb->len);
205 if (rc <= 0)
206 break;
207 delay = msecs_to_jiffies(rc);
208 if (delay > *timeo || delay < 0)
209 goto do_nonblock;
210
211 sk->sk_write_pending++;
212 release_sock(sk);
213 *timeo -= schedule_timeout(delay);
214 lock_sock(sk);
215 sk->sk_write_pending--;
216 }
217 out:
218 finish_wait(sk->sk_sleep, &wait);
219 return rc;
220
221 do_error:
222 rc = -EPIPE;
223 goto out;
224 do_nonblock:
225 rc = -EAGAIN;
226 goto out;
227 do_interrupted:
228 rc = sock_intr_errno(*timeo);
229 goto out;
230 }
231
232 int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)
233 {
234 const struct dccp_sock *dp = dccp_sk(sk);
235 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
236 skb->len);
237
238 if (err > 0)
239 err = dccp_wait_for_ccid(sk, skb, timeo);
240
241 if (err == 0) {
242 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
243 const int len = skb->len;
244
245 if (sk->sk_state == DCCP_PARTOPEN) {
246 /* See 8.1.5. Handshake Completion */
247 inet_csk_schedule_ack(sk);
248 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
249 inet_csk(sk)->icsk_rto,
250 DCCP_RTO_MAX);
251 dcb->dccpd_type = DCCP_PKT_DATAACK;
252 } else if (dccp_ack_pending(sk))
253 dcb->dccpd_type = DCCP_PKT_DATAACK;
254 else
255 dcb->dccpd_type = DCCP_PKT_DATA;
256
257 err = dccp_transmit_skb(sk, skb);
258 ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
259 } else
260 kfree_skb(skb);
261
262 return err;
263 }
264
265 int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
266 {
267 if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
268 return -EHOSTUNREACH; /* Routing failure or similar. */
269
270 return dccp_transmit_skb(sk, (skb_cloned(skb) ?
271 pskb_copy(skb, GFP_ATOMIC):
272 skb_clone(skb, GFP_ATOMIC)));
273 }
274
275 struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
276 struct request_sock *req)
277 {
278 struct dccp_hdr *dh;
279 struct dccp_request_sock *dreq;
280 const int dccp_header_size = sizeof(struct dccp_hdr) +
281 sizeof(struct dccp_hdr_ext) +
282 sizeof(struct dccp_hdr_response);
283 struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN +
284 dccp_header_size, 1,
285 GFP_ATOMIC);
286 if (skb == NULL)
287 return NULL;
288
289 /* Reserve space for headers. */
290 skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size);
291
292 skb->dst = dst_clone(dst);
293 skb->csum = 0;
294
295 dreq = dccp_rsk(req);
296 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
297 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
298 dccp_insert_options(sk, skb);
299
300 skb->h.raw = skb_push(skb, dccp_header_size);
301
302 dh = dccp_hdr(skb);
303 memset(dh, 0, dccp_header_size);
304
305 dh->dccph_sport = inet_sk(sk)->sport;
306 dh->dccph_dport = inet_rsk(req)->rmt_port;
307 dh->dccph_doff = (dccp_header_size +
308 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
309 dh->dccph_type = DCCP_PKT_RESPONSE;
310 dh->dccph_x = 1;
311 dccp_hdr_set_seq(dh, dreq->dreq_iss);
312 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
313 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
314
315 dh->dccph_checksum = dccp_v4_checksum(skb, inet_rsk(req)->loc_addr,
316 inet_rsk(req)->rmt_addr);
317
318 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
319 return skb;
320 }
321
322 struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
323 const enum dccp_reset_codes code)
324
325 {
326 struct dccp_hdr *dh;
327 struct dccp_sock *dp = dccp_sk(sk);
328 const int dccp_header_size = sizeof(struct dccp_hdr) +
329 sizeof(struct dccp_hdr_ext) +
330 sizeof(struct dccp_hdr_reset);
331 struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN +
332 dccp_header_size, 1,
333 GFP_ATOMIC);
334 if (skb == NULL)
335 return NULL;
336
337 /* Reserve space for headers. */
338 skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size);
339
340 skb->dst = dst_clone(dst);
341 skb->csum = 0;
342
343 dccp_inc_seqno(&dp->dccps_gss);
344
345 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
346 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
347 DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
348 dccp_insert_options(sk, skb);
349
350 skb->h.raw = skb_push(skb, dccp_header_size);
351
352 dh = dccp_hdr(skb);
353 memset(dh, 0, dccp_header_size);
354
355 dh->dccph_sport = inet_sk(sk)->sport;
356 dh->dccph_dport = inet_sk(sk)->dport;
357 dh->dccph_doff = (dccp_header_size +
358 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
359 dh->dccph_type = DCCP_PKT_RESET;
360 dh->dccph_x = 1;
361 dccp_hdr_set_seq(dh, dp->dccps_gss);
362 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
363
364 dccp_hdr_reset(skb)->dccph_reset_code = code;
365
366 dh->dccph_checksum = dccp_v4_checksum(skb, inet_sk(sk)->saddr,
367 inet_sk(sk)->daddr);
368
369 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
370 return skb;
371 }
372
373 /*
374 * Do all connect socket setups that can be done AF independent.
375 */
376 static inline void dccp_connect_init(struct sock *sk)
377 {
378 struct dst_entry *dst = __sk_dst_get(sk);
379 struct inet_connection_sock *icsk = inet_csk(sk);
380
381 sk->sk_err = 0;
382 sock_reset_flag(sk, SOCK_DONE);
383
384 dccp_sync_mss(sk, dst_mtu(dst));
385
386 /*
387 * FIXME: set dp->{dccps_swh,dccps_swl}, with
388 * something like dccp_inc_seq
389 */
390
391 icsk->icsk_retransmits = 0;
392 }
393
394 int dccp_connect(struct sock *sk)
395 {
396 struct sk_buff *skb;
397 struct inet_connection_sock *icsk = inet_csk(sk);
398
399 dccp_connect_init(sk);
400
401 skb = alloc_skb(MAX_DCCP_HEADER + 15, sk->sk_allocation);
402 if (unlikely(skb == NULL))
403 return -ENOBUFS;
404
405 /* Reserve space for headers. */
406 skb_reserve(skb, MAX_DCCP_HEADER);
407
408 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
409 skb->csum = 0;
410
411 dccp_skb_entail(sk, skb);
412 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
413 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
414
415 /* Timer for repeating the REQUEST until an answer. */
416 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
417 icsk->icsk_rto, DCCP_RTO_MAX);
418 return 0;
419 }
420
421 void dccp_send_ack(struct sock *sk)
422 {
423 /* If we have been reset, we may not send again. */
424 if (sk->sk_state != DCCP_CLOSED) {
425 struct sk_buff *skb = alloc_skb(MAX_DCCP_HEADER, GFP_ATOMIC);
426
427 if (skb == NULL) {
428 inet_csk_schedule_ack(sk);
429 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
430 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
431 TCP_DELACK_MAX,
432 DCCP_RTO_MAX);
433 return;
434 }
435
436 /* Reserve space for headers */
437 skb_reserve(skb, MAX_DCCP_HEADER);
438 skb->csum = 0;
439 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
440 dccp_transmit_skb(sk, skb);
441 }
442 }
443
444 EXPORT_SYMBOL_GPL(dccp_send_ack);
445
446 void dccp_send_delayed_ack(struct sock *sk)
447 {
448 struct inet_connection_sock *icsk = inet_csk(sk);
449 /*
450 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
451 * with using 2s, and active senders also piggyback the ACK into a
452 * DATAACK packet, so this is really for quiescent senders.
453 */
454 unsigned long timeout = jiffies + 2 * HZ;
455
456 /* Use new timeout only if there wasn't a older one earlier. */
457 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
458 /* If delack timer was blocked or is about to expire,
459 * send ACK now.
460 *
461 * FIXME: check the "about to expire" part
462 */
463 if (icsk->icsk_ack.blocked) {
464 dccp_send_ack(sk);
465 return;
466 }
467
468 if (!time_before(timeout, icsk->icsk_ack.timeout))
469 timeout = icsk->icsk_ack.timeout;
470 }
471 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
472 icsk->icsk_ack.timeout = timeout;
473 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
474 }
475
476 void dccp_send_sync(struct sock *sk, const u64 seq,
477 const enum dccp_pkt_type pkt_type)
478 {
479 /*
480 * We are not putting this on the write queue, so
481 * dccp_transmit_skb() will set the ownership to this
482 * sock.
483 */
484 struct sk_buff *skb = alloc_skb(MAX_DCCP_HEADER, GFP_ATOMIC);
485
486 if (skb == NULL)
487 /* FIXME: how to make sure the sync is sent? */
488 return;
489
490 /* Reserve space for headers and prepare control bits. */
491 skb_reserve(skb, MAX_DCCP_HEADER);
492 skb->csum = 0;
493 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
494 DCCP_SKB_CB(skb)->dccpd_seq = seq;
495
496 dccp_transmit_skb(sk, skb);
497 }
498
499 /*
500 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
501 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
502 * any circumstances.
503 */
504 void dccp_send_close(struct sock *sk, const int active)
505 {
506 struct dccp_sock *dp = dccp_sk(sk);
507 struct sk_buff *skb;
508 const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
509
510 skb = alloc_skb(sk->sk_prot->max_header, prio);
511 if (skb == NULL)
512 return;
513
514 /* Reserve space for headers and prepare control bits. */
515 skb_reserve(skb, sk->sk_prot->max_header);
516 skb->csum = 0;
517 DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
518 DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
519
520 if (active) {
521 dccp_skb_entail(sk, skb);
522 dccp_transmit_skb(sk, skb_clone(skb, prio));
523 } else
524 dccp_transmit_skb(sk, skb);
525 }
Linus' kernel tree