[DCCP]: Use skb_set_owner_w in dccp_transmit_skb when skb->sk is NULL
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / dccp / output.c
blob946ec2db75de74a1170657e7e5f5f591ec35ce4a
1 /*
2 * net/dccp/output.c
3 *
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/config.h>
14 #include <linux/dccp.h>
15 #include <linux/skbuff.h>
17 #include <net/sock.h>
19 #include "ackvec.h"
20 #include "ccid.h"
21 #include "dccp.h"
23 static inline void dccp_event_ack_sent(struct sock *sk)
25 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
29 * All SKB's seen here are completely headerless. It is our
30 * job to build the DCCP header, and pass the packet down to
31 * IP so it can do the same plus pass the packet off to the
32 * device.
34 int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
36 if (likely(skb != NULL)) {
37 const struct inet_sock *inet = inet_sk(sk);
38 struct dccp_sock *dp = dccp_sk(sk);
39 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
40 struct dccp_hdr *dh;
41 /* XXX For now we're using only 48 bits sequence numbers */
42 const int dccp_header_size = sizeof(*dh) +
43 sizeof(struct dccp_hdr_ext) +
44 dccp_packet_hdr_len(dcb->dccpd_type);
45 int err, set_ack = 1;
46 u64 ackno = dp->dccps_gsr;
48 dccp_inc_seqno(&dp->dccps_gss);
50 switch (dcb->dccpd_type) {
51 case DCCP_PKT_DATA:
52 set_ack = 0;
53 break;
54 case DCCP_PKT_SYNC:
55 case DCCP_PKT_SYNCACK:
56 ackno = dcb->dccpd_seq;
57 break;
60 dcb->dccpd_seq = dp->dccps_gss;
61 dccp_insert_options(sk, skb);
63 skb->h.raw = skb_push(skb, dccp_header_size);
64 dh = dccp_hdr(skb);
66 if (!skb->sk)
67 skb_set_owner_w(skb, sk);
69 /* Build DCCP header and checksum it. */
70 memset(dh, 0, dccp_header_size);
71 dh->dccph_type = dcb->dccpd_type;
72 dh->dccph_sport = inet->sport;
73 dh->dccph_dport = inet->dport;
74 dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
75 dh->dccph_ccval = dcb->dccpd_ccval;
76 /* XXX For now we're using only 48 bits sequence numbers */
77 dh->dccph_x = 1;
79 dp->dccps_awh = dp->dccps_gss;
80 dccp_hdr_set_seq(dh, dp->dccps_gss);
81 if (set_ack)
82 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
84 switch (dcb->dccpd_type) {
85 case DCCP_PKT_REQUEST:
86 dccp_hdr_request(skb)->dccph_req_service =
87 dp->dccps_service;
88 break;
89 case DCCP_PKT_RESET:
90 dccp_hdr_reset(skb)->dccph_reset_code =
91 dcb->dccpd_reset_code;
92 break;
95 dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr,
96 inet->daddr);
98 if (set_ack)
99 dccp_event_ack_sent(sk);
101 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
103 err = ip_queue_xmit(skb, 0);
104 if (err <= 0)
105 return err;
107 /* NET_XMIT_CN is special. It does not guarantee,
108 * that this packet is lost. It tells that device
109 * is about to start to drop packets or already
110 * drops some packets of the same priority and
111 * invokes us to send less aggressively.
113 return err == NET_XMIT_CN ? 0 : err;
115 return -ENOBUFS;
118 unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
120 struct dccp_sock *dp = dccp_sk(sk);
121 int mss_now;
124 * FIXME: we really should be using the af_specific thing to support
125 * IPv6.
126 * mss_now = pmtu - tp->af_specific->net_header_len -
127 * sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext);
129 mss_now = pmtu - sizeof(struct iphdr) - sizeof(struct dccp_hdr) -
130 sizeof(struct dccp_hdr_ext);
132 /* Now subtract optional transport overhead */
133 mss_now -= dp->dccps_ext_header_len;
136 * FIXME: this should come from the CCID infrastructure, where, say,
137 * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
138 * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
139 * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
140 * make it a multiple of 4
143 mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
145 /* And store cached results */
146 dp->dccps_pmtu_cookie = pmtu;
147 dp->dccps_mss_cache = mss_now;
149 return mss_now;
152 void dccp_write_space(struct sock *sk)
154 read_lock(&sk->sk_callback_lock);
156 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
157 wake_up_interruptible(sk->sk_sleep);
158 /* Should agree with poll, otherwise some programs break */
159 if (sock_writeable(sk))
160 sk_wake_async(sk, 2, POLL_OUT);
162 read_unlock(&sk->sk_callback_lock);
166 * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
167 * @sk: socket to wait for
168 * @timeo: for how long
170 static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
171 long *timeo)
173 struct dccp_sock *dp = dccp_sk(sk);
174 DEFINE_WAIT(wait);
175 long delay;
176 int rc;
178 while (1) {
179 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
181 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
182 goto do_error;
183 if (!*timeo)
184 goto do_nonblock;
185 if (signal_pending(current))
186 goto do_interrupted;
188 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
189 skb->len);
190 if (rc <= 0)
191 break;
192 delay = msecs_to_jiffies(rc);
193 if (delay > *timeo || delay < 0)
194 goto do_nonblock;
196 sk->sk_write_pending++;
197 release_sock(sk);
198 *timeo -= schedule_timeout(delay);
199 lock_sock(sk);
200 sk->sk_write_pending--;
202 out:
203 finish_wait(sk->sk_sleep, &wait);
204 return rc;
206 do_error:
207 rc = -EPIPE;
208 goto out;
209 do_nonblock:
210 rc = -EAGAIN;
211 goto out;
212 do_interrupted:
213 rc = sock_intr_errno(*timeo);
214 goto out;
217 int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)
219 const struct dccp_sock *dp = dccp_sk(sk);
220 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
221 skb->len);
223 if (err > 0)
224 err = dccp_wait_for_ccid(sk, skb, timeo);
226 if (err == 0) {
227 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
228 const int len = skb->len;
230 if (sk->sk_state == DCCP_PARTOPEN) {
231 /* See 8.1.5. Handshake Completion */
232 inet_csk_schedule_ack(sk);
233 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
234 inet_csk(sk)->icsk_rto,
235 DCCP_RTO_MAX);
236 dcb->dccpd_type = DCCP_PKT_DATAACK;
237 } else if (dccp_ack_pending(sk))
238 dcb->dccpd_type = DCCP_PKT_DATAACK;
239 else
240 dcb->dccpd_type = DCCP_PKT_DATA;
242 err = dccp_transmit_skb(sk, skb);
243 ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
246 return err;
249 int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
251 if (inet_sk_rebuild_header(sk) != 0)
252 return -EHOSTUNREACH; /* Routing failure or similar. */
254 return dccp_transmit_skb(sk, (skb_cloned(skb) ?
255 pskb_copy(skb, GFP_ATOMIC):
256 skb_clone(skb, GFP_ATOMIC)));
259 struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
260 struct request_sock *req)
262 struct dccp_hdr *dh;
263 struct dccp_request_sock *dreq;
264 const int dccp_header_size = sizeof(struct dccp_hdr) +
265 sizeof(struct dccp_hdr_ext) +
266 sizeof(struct dccp_hdr_response);
267 struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN +
268 dccp_header_size, 1,
269 GFP_ATOMIC);
270 if (skb == NULL)
271 return NULL;
273 /* Reserve space for headers. */
274 skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size);
276 skb->dst = dst_clone(dst);
277 skb->csum = 0;
279 dreq = dccp_rsk(req);
280 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
281 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
282 dccp_insert_options(sk, skb);
284 skb->h.raw = skb_push(skb, dccp_header_size);
286 dh = dccp_hdr(skb);
287 memset(dh, 0, dccp_header_size);
289 dh->dccph_sport = inet_sk(sk)->sport;
290 dh->dccph_dport = inet_rsk(req)->rmt_port;
291 dh->dccph_doff = (dccp_header_size +
292 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
293 dh->dccph_type = DCCP_PKT_RESPONSE;
294 dh->dccph_x = 1;
295 dccp_hdr_set_seq(dh, dreq->dreq_iss);
296 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
297 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
299 dh->dccph_checksum = dccp_v4_checksum(skb, inet_rsk(req)->loc_addr,
300 inet_rsk(req)->rmt_addr);
302 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
303 return skb;
306 struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
307 const enum dccp_reset_codes code)
310 struct dccp_hdr *dh;
311 struct dccp_sock *dp = dccp_sk(sk);
312 const int dccp_header_size = sizeof(struct dccp_hdr) +
313 sizeof(struct dccp_hdr_ext) +
314 sizeof(struct dccp_hdr_reset);
315 struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN +
316 dccp_header_size, 1,
317 GFP_ATOMIC);
318 if (skb == NULL)
319 return NULL;
321 /* Reserve space for headers. */
322 skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size);
324 skb->dst = dst_clone(dst);
325 skb->csum = 0;
327 dccp_inc_seqno(&dp->dccps_gss);
329 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
330 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
331 DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
332 dccp_insert_options(sk, skb);
334 skb->h.raw = skb_push(skb, dccp_header_size);
336 dh = dccp_hdr(skb);
337 memset(dh, 0, dccp_header_size);
339 dh->dccph_sport = inet_sk(sk)->sport;
340 dh->dccph_dport = inet_sk(sk)->dport;
341 dh->dccph_doff = (dccp_header_size +
342 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
343 dh->dccph_type = DCCP_PKT_RESET;
344 dh->dccph_x = 1;
345 dccp_hdr_set_seq(dh, dp->dccps_gss);
346 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
348 dccp_hdr_reset(skb)->dccph_reset_code = code;
350 dh->dccph_checksum = dccp_v4_checksum(skb, inet_sk(sk)->saddr,
351 inet_sk(sk)->daddr);
353 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
354 return skb;
358 * Do all connect socket setups that can be done AF independent.
360 static inline void dccp_connect_init(struct sock *sk)
362 struct dst_entry *dst = __sk_dst_get(sk);
363 struct inet_connection_sock *icsk = inet_csk(sk);
365 sk->sk_err = 0;
366 sock_reset_flag(sk, SOCK_DONE);
368 dccp_sync_mss(sk, dst_mtu(dst));
371 * FIXME: set dp->{dccps_swh,dccps_swl}, with
372 * something like dccp_inc_seq
375 icsk->icsk_retransmits = 0;
378 int dccp_connect(struct sock *sk)
380 struct sk_buff *skb;
381 struct inet_connection_sock *icsk = inet_csk(sk);
383 dccp_connect_init(sk);
385 skb = alloc_skb(MAX_DCCP_HEADER + 15, sk->sk_allocation);
386 if (unlikely(skb == NULL))
387 return -ENOBUFS;
389 /* Reserve space for headers. */
390 skb_reserve(skb, MAX_DCCP_HEADER);
392 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
393 skb->csum = 0;
394 skb_set_owner_w(skb, sk);
396 BUG_TRAP(sk->sk_send_head == NULL);
397 sk->sk_send_head = skb;
398 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
399 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
401 /* Timer for repeating the REQUEST until an answer. */
402 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
403 icsk->icsk_rto, DCCP_RTO_MAX);
404 return 0;
407 void dccp_send_ack(struct sock *sk)
409 /* If we have been reset, we may not send again. */
410 if (sk->sk_state != DCCP_CLOSED) {
411 struct sk_buff *skb = alloc_skb(MAX_DCCP_HEADER, GFP_ATOMIC);
413 if (skb == NULL) {
414 inet_csk_schedule_ack(sk);
415 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
416 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
417 TCP_DELACK_MAX,
418 DCCP_RTO_MAX);
419 return;
422 /* Reserve space for headers */
423 skb_reserve(skb, MAX_DCCP_HEADER);
424 skb->csum = 0;
425 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
426 skb_set_owner_w(skb, sk);
427 dccp_transmit_skb(sk, skb);
431 EXPORT_SYMBOL_GPL(dccp_send_ack);
433 void dccp_send_delayed_ack(struct sock *sk)
435 struct inet_connection_sock *icsk = inet_csk(sk);
437 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
438 * with using 2s, and active senders also piggyback the ACK into a
439 * DATAACK packet, so this is really for quiescent senders.
441 unsigned long timeout = jiffies + 2 * HZ;
443 /* Use new timeout only if there wasn't a older one earlier. */
444 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
445 /* If delack timer was blocked or is about to expire,
446 * send ACK now.
448 * FIXME: check the "about to expire" part
450 if (icsk->icsk_ack.blocked) {
451 dccp_send_ack(sk);
452 return;
455 if (!time_before(timeout, icsk->icsk_ack.timeout))
456 timeout = icsk->icsk_ack.timeout;
458 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
459 icsk->icsk_ack.timeout = timeout;
460 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
463 void dccp_send_sync(struct sock *sk, const u64 seq,
464 const enum dccp_pkt_type pkt_type)
467 * We are not putting this on the write queue, so
468 * dccp_transmit_skb() will set the ownership to this
469 * sock.
471 struct sk_buff *skb = alloc_skb(MAX_DCCP_HEADER, GFP_ATOMIC);
473 if (skb == NULL)
474 /* FIXME: how to make sure the sync is sent? */
475 return;
477 /* Reserve space for headers and prepare control bits. */
478 skb_reserve(skb, MAX_DCCP_HEADER);
479 skb->csum = 0;
480 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
481 DCCP_SKB_CB(skb)->dccpd_seq = seq;
483 skb_set_owner_w(skb, sk);
484 dccp_transmit_skb(sk, skb);
488 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
489 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
490 * any circumstances.
492 void dccp_send_close(struct sock *sk, const int active)
494 struct dccp_sock *dp = dccp_sk(sk);
495 struct sk_buff *skb;
496 const unsigned int prio = active ? GFP_KERNEL : GFP_ATOMIC;
498 skb = alloc_skb(sk->sk_prot->max_header, prio);
499 if (skb == NULL)
500 return;
502 /* Reserve space for headers and prepare control bits. */
503 skb_reserve(skb, sk->sk_prot->max_header);
504 skb->csum = 0;
505 DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
506 DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
508 skb_set_owner_w(skb, sk);
509 if (active) {
510 BUG_TRAP(sk->sk_send_head == NULL);
511 sk->sk_send_head = skb;
512 dccp_transmit_skb(sk, skb_clone(skb, prio));
513 } else
514 dccp_transmit_skb(sk, skb);