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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
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
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070013#include <linux/dccp.h>
Herbert Xu48918a42005-10-30 11:20:59 +110014#include <linux/kernel.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070015#include <linux/skbuff.h>
16
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020017#include <net/inet_sock.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070018#include <net/sock.h>
19
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070020#include "ackvec.h"
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070021#include "ccid.h"
22#include "dccp.h"
23
24static inline void dccp_event_ack_sent(struct sock *sk)
25{
26 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
27}
28
Arnaldo Carvalho de Meloc25a18b2006-03-20 21:58:56 -080029static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb)
Herbert Xu48918a42005-10-30 11:20:59 +110030{
31 skb_set_owner_w(skb, sk);
32 WARN_ON(sk->sk_send_head);
33 sk->sk_send_head = skb;
34}
35
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070036/*
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 */
Herbert Xu48918a42005-10-30 11:20:59 +110042static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070043{
44 if (likely(skb != NULL)) {
45 const struct inet_sock *inet = inet_sk(sk);
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -080046 const struct inet_connection_sock *icsk = inet_csk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070047 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 */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -080051 const u32 dccp_header_size = sizeof(*dh) +
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070052 sizeof(struct dccp_hdr_ext) +
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -030053 dccp_packet_hdr_len(dcb->dccpd_type);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070054 int err, set_ack = 1;
55 u64 ackno = dp->dccps_gsr;
56
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070057 dccp_inc_seqno(&dp->dccps_gss);
58
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070059 switch (dcb->dccpd_type) {
60 case DCCP_PKT_DATA:
61 set_ack = 0;
Herbert Xuedc9e812005-10-30 11:20:59 +110062 /* fall through */
63 case DCCP_PKT_DATAACK:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070064 break;
Herbert Xuedc9e812005-10-30 11:20:59 +110065
Andrea Bittauafe00252006-03-20 17:43:56 -080066 case DCCP_PKT_REQUEST:
67 set_ack = 0;
68 /* fall through */
69
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070070 case DCCP_PKT_SYNC:
71 case DCCP_PKT_SYNCACK:
72 ackno = dcb->dccpd_seq;
Herbert Xuedc9e812005-10-30 11:20:59 +110073 /* 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);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070081 break;
82 }
Arnaldo Carvalho de Melo24117722005-08-21 05:40:16 -030083
84 dcb->dccpd_seq = dp->dccps_gss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -080085
86 if (dccp_insert_options(sk, skb)) {
87 kfree_skb(skb);
88 return -EPROTO;
89 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070090
Herbert Xufda0fd62005-10-14 16:38:49 +100091
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070092 /* Build DCCP header and checksum it. */
Gerrit Renker9b420782006-11-10 11:22:32 -020093 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070094 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;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -020099 dh->dccph_cscov = dp->dccps_pcslen;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700100 /* 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:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300110 dccp_hdr_request(skb)->dccph_req_service =
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700111 dp->dccps_service;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700112 break;
113 case DCCP_PKT_RESET:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300114 dccp_hdr_reset(skb)->dccph_reset_code =
115 dcb->dccpd_reset_code;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700116 break;
117 }
118
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200119 icsk->icsk_af_ops->send_check(sk, 0, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700120
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700121 if (set_ack)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700122 dccp_event_ack_sent(sk);
123
124 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
125
Herbert Xu49c5bfa2005-10-18 12:03:28 +1000126 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
David S. Miller93173112006-11-09 19:58:25 -0800127 err = icsk->icsk_af_ops->queue_xmit(skb, sk, 0);
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200128 return net_xmit_eval(err);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700129 }
130 return -ENOBUFS;
131}
132
133unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
134{
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800135 struct inet_connection_sock *icsk = inet_csk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700136 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800137 int mss_now = (pmtu - icsk->icsk_af_ops->net_header_len -
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800138 sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700139
140 /* Now subtract optional transport overhead */
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800141 mss_now -= icsk->icsk_ext_hdr_len;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700142
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 */
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800154 icsk->icsk_pmtu_cookie = pmtu;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700155 dp->dccps_mss_cache = mss_now;
156
157 return mss_now;
158}
159
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800160EXPORT_SYMBOL_GPL(dccp_sync_mss);
161
Arnaldo Carvalho de Meloc530cfb2005-08-29 02:15:54 -0300162void 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
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300175/**
176 * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
177 * @sk: socket to wait for
178 * @timeo: for how long
179 */
180static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
181 long *timeo)
182{
183 struct dccp_sock *dp = dccp_sk(sk);
184 DEFINE_WAIT(wait);
185 long delay;
186 int rc;
187
188 while (1) {
189 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
190
Ian McDonald97e58482006-08-26 19:16:45 -0700191 if (sk->sk_err)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300192 goto do_error;
193 if (!*timeo)
194 goto do_nonblock;
195 if (signal_pending(current))
196 goto do_interrupted;
197
198 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
199 skb->len);
200 if (rc <= 0)
201 break;
202 delay = msecs_to_jiffies(rc);
203 if (delay > *timeo || delay < 0)
204 goto do_nonblock;
205
206 sk->sk_write_pending++;
207 release_sock(sk);
208 *timeo -= schedule_timeout(delay);
209 lock_sock(sk);
210 sk->sk_write_pending--;
211 }
212out:
213 finish_wait(sk->sk_sleep, &wait);
214 return rc;
215
216do_error:
217 rc = -EPIPE;
218 goto out;
219do_nonblock:
220 rc = -EAGAIN;
221 goto out;
222do_interrupted:
223 rc = sock_intr_errno(*timeo);
224 goto out;
225}
226
Ian McDonald97e58482006-08-26 19:16:45 -0700227static void dccp_write_xmit_timer(unsigned long data) {
228 struct sock *sk = (struct sock *)data;
229 struct dccp_sock *dp = dccp_sk(sk);
230
231 bh_lock_sock(sk);
232 if (sock_owned_by_user(sk))
233 sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);
234 else
235 dccp_write_xmit(sk, 0);
236 bh_unlock_sock(sk);
237 sock_put(sk);
238}
239
240void dccp_write_xmit(struct sock *sk, int block)
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700241{
Ian McDonald97e58482006-08-26 19:16:45 -0700242 struct dccp_sock *dp = dccp_sk(sk);
243 struct sk_buff *skb;
Ian McDonaldf45b3ec2006-11-10 13:09:10 -0200244 long timeo = DCCP_XMIT_TIMEO; /* If a packet is taking longer than
245 this we have other issues */
Ian McDonald97e58482006-08-26 19:16:45 -0700246
247 while ((skb = skb_peek(&sk->sk_write_queue))) {
248 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300249 skb->len);
250
Ian McDonald97e58482006-08-26 19:16:45 -0700251 if (err > 0) {
252 if (!block) {
253 sk_reset_timer(sk, &dp->dccps_xmit_timer,
254 msecs_to_jiffies(err)+jiffies);
255 break;
Ian McDonaldf45b3ec2006-11-10 13:09:10 -0200256 } else {
Ian McDonald97e58482006-08-26 19:16:45 -0700257 err = dccp_wait_for_ccid(sk, skb, &timeo);
Ian McDonaldf45b3ec2006-11-10 13:09:10 -0200258 timeo = DCCP_XMIT_TIMEO;
259 }
Ian McDonald97e58482006-08-26 19:16:45 -0700260 if (err) {
261 printk(KERN_CRIT "%s:err at dccp_wait_for_ccid"
262 " %d\n", __FUNCTION__, err);
263 dump_stack();
264 }
265 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700266
Ian McDonald97e58482006-08-26 19:16:45 -0700267 skb_dequeue(&sk->sk_write_queue);
268 if (err == 0) {
269 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
270 const int len = skb->len;
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700271
Ian McDonald97e58482006-08-26 19:16:45 -0700272 if (sk->sk_state == DCCP_PARTOPEN) {
273 /* See 8.1.5. Handshake Completion */
274 inet_csk_schedule_ack(sk);
275 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700276 inet_csk(sk)->icsk_rto,
277 DCCP_RTO_MAX);
Ian McDonald97e58482006-08-26 19:16:45 -0700278 dcb->dccpd_type = DCCP_PKT_DATAACK;
279 } else if (dccp_ack_pending(sk))
280 dcb->dccpd_type = DCCP_PKT_DATAACK;
281 else
282 dcb->dccpd_type = DCCP_PKT_DATA;
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700283
Ian McDonald97e58482006-08-26 19:16:45 -0700284 err = dccp_transmit_skb(sk, skb);
285 ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
286 if (err) {
287 printk(KERN_CRIT "%s:err from "
288 "ccid_hc_tx_packet_sent %d\n",
289 __FUNCTION__, err);
290 dump_stack();
291 }
292 } else
293 kfree(skb);
294 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700295}
296
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700297int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
298{
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800299 if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700300 return -EHOSTUNREACH; /* Routing failure or similar. */
301
302 return dccp_transmit_skb(sk, (skb_cloned(skb) ?
303 pskb_copy(skb, GFP_ATOMIC):
304 skb_clone(skb, GFP_ATOMIC)));
305}
306
307struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
308 struct request_sock *req)
309{
310 struct dccp_hdr *dh;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700311 struct dccp_request_sock *dreq;
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800312 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700313 sizeof(struct dccp_hdr_ext) +
314 sizeof(struct dccp_hdr_response);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800315 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700316 GFP_ATOMIC);
317 if (skb == NULL)
318 return NULL;
319
320 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800321 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700322
323 skb->dst = dst_clone(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700324
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700325 dreq = dccp_rsk(req);
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200326 if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
327 dccp_inc_seqno(&dreq->dreq_iss);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700328 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700329 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800330
331 if (dccp_insert_options(sk, skb)) {
332 kfree_skb(skb);
333 return NULL;
334 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700335
Gerrit Renker9b420782006-11-10 11:22:32 -0200336 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700337
338 dh->dccph_sport = inet_sk(sk)->sport;
339 dh->dccph_dport = inet_rsk(req)->rmt_port;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300340 dh->dccph_doff = (dccp_header_size +
341 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700342 dh->dccph_type = DCCP_PKT_RESPONSE;
343 dh->dccph_x = 1;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700344 dccp_hdr_set_seq(dh, dreq->dreq_iss);
345 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
346 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700347
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200348 dccp_csum_outgoing(skb);
349
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200350 /* We use `acked' to remember that a Response was already sent. */
351 inet_rsk(req)->acked = 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700352 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
353 return skb;
354}
355
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800356EXPORT_SYMBOL_GPL(dccp_make_response);
357
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800358static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
359 const enum dccp_reset_codes code)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700360
361{
362 struct dccp_hdr *dh;
363 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800364 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700365 sizeof(struct dccp_hdr_ext) +
366 sizeof(struct dccp_hdr_reset);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800367 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700368 GFP_ATOMIC);
369 if (skb == NULL)
370 return NULL;
371
372 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800373 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700374
375 skb->dst = dst_clone(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700376
377 dccp_inc_seqno(&dp->dccps_gss);
378
379 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
380 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
381 DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800382
383 if (dccp_insert_options(sk, skb)) {
384 kfree_skb(skb);
385 return NULL;
386 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700387
Gerrit Renker9b420782006-11-10 11:22:32 -0200388 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700389
390 dh->dccph_sport = inet_sk(sk)->sport;
391 dh->dccph_dport = inet_sk(sk)->dport;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300392 dh->dccph_doff = (dccp_header_size +
393 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700394 dh->dccph_type = DCCP_PKT_RESET;
395 dh->dccph_x = 1;
396 dccp_hdr_set_seq(dh, dp->dccps_gss);
397 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
398
399 dccp_hdr_reset(skb)->dccph_reset_code = code;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200400 inet_csk(sk)->icsk_af_ops->send_check(sk, 0, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700401
402 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
403 return skb;
404}
405
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800406int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
407{
408 /*
409 * FIXME: what if rebuild_header fails?
410 * Should we be doing a rebuild_header here?
411 */
412 int err = inet_sk_rebuild_header(sk);
413
414 if (err == 0) {
415 struct sk_buff *skb = dccp_make_reset(sk, sk->sk_dst_cache,
416 code);
417 if (skb != NULL) {
418 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
David S. Miller93173112006-11-09 19:58:25 -0800419 err = inet_csk(sk)->icsk_af_ops->queue_xmit(skb, sk, 0);
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200420 return net_xmit_eval(err);
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800421 }
422 }
423
424 return err;
425}
426
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700427/*
428 * Do all connect socket setups that can be done AF independent.
429 */
430static inline void dccp_connect_init(struct sock *sk)
431{
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800432 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700433 struct dst_entry *dst = __sk_dst_get(sk);
434 struct inet_connection_sock *icsk = inet_csk(sk);
435
436 sk->sk_err = 0;
437 sock_reset_flag(sk, SOCK_DONE);
438
439 dccp_sync_mss(sk, dst_mtu(dst));
440
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800441 /*
442 * SWL and AWL are initially adjusted so that they are not less than
443 * the initial Sequence Numbers received and sent, respectively:
444 * SWL := max(GSR + 1 - floor(W/4), ISR),
445 * AWL := max(GSS - W' + 1, ISS).
446 * These adjustments MUST be applied only at the beginning of the
447 * connection.
448 */
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200449 dccp_update_gss(sk, dp->dccps_iss);
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800450 dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700451
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200452 /* S.GAR - greatest valid acknowledgement number received on a non-Sync;
453 * initialized to S.ISS (sec. 8.5) */
454 dp->dccps_gar = dp->dccps_iss;
455
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700456 icsk->icsk_retransmits = 0;
Ian McDonald97e58482006-08-26 19:16:45 -0700457 init_timer(&dp->dccps_xmit_timer);
458 dp->dccps_xmit_timer.data = (unsigned long)sk;
459 dp->dccps_xmit_timer.function = dccp_write_xmit_timer;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700460}
461
462int dccp_connect(struct sock *sk)
463{
464 struct sk_buff *skb;
465 struct inet_connection_sock *icsk = inet_csk(sk);
466
467 dccp_connect_init(sk);
468
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800469 skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700470 if (unlikely(skb == NULL))
471 return -ENOBUFS;
472
473 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800474 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700475
476 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700477
Herbert Xu48918a42005-10-30 11:20:59 +1100478 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700479 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
480 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
481
482 /* Timer for repeating the REQUEST until an answer. */
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700483 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
484 icsk->icsk_rto, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700485 return 0;
486}
487
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800488EXPORT_SYMBOL_GPL(dccp_connect);
489
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700490void dccp_send_ack(struct sock *sk)
491{
492 /* If we have been reset, we may not send again. */
493 if (sk->sk_state != DCCP_CLOSED) {
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800494 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
495 GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700496
497 if (skb == NULL) {
498 inet_csk_schedule_ack(sk);
499 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300500 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
501 TCP_DELACK_MAX,
502 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700503 return;
504 }
505
506 /* Reserve space for headers */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800507 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700508 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700509 dccp_transmit_skb(sk, skb);
510 }
511}
512
513EXPORT_SYMBOL_GPL(dccp_send_ack);
514
515void dccp_send_delayed_ack(struct sock *sk)
516{
517 struct inet_connection_sock *icsk = inet_csk(sk);
518 /*
519 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
520 * with using 2s, and active senders also piggyback the ACK into a
521 * DATAACK packet, so this is really for quiescent senders.
522 */
523 unsigned long timeout = jiffies + 2 * HZ;
524
525 /* Use new timeout only if there wasn't a older one earlier. */
526 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
527 /* If delack timer was blocked or is about to expire,
528 * send ACK now.
529 *
530 * FIXME: check the "about to expire" part
531 */
532 if (icsk->icsk_ack.blocked) {
533 dccp_send_ack(sk);
534 return;
535 }
536
537 if (!time_before(timeout, icsk->icsk_ack.timeout))
538 timeout = icsk->icsk_ack.timeout;
539 }
540 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
541 icsk->icsk_ack.timeout = timeout;
542 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
543}
544
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300545void dccp_send_sync(struct sock *sk, const u64 seq,
546 const enum dccp_pkt_type pkt_type)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700547{
548 /*
549 * We are not putting this on the write queue, so
550 * dccp_transmit_skb() will set the ownership to this
551 * sock.
552 */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800553 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700554
555 if (skb == NULL)
556 /* FIXME: how to make sure the sync is sent? */
557 return;
558
559 /* Reserve space for headers and prepare control bits. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800560 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300561 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700562 DCCP_SKB_CB(skb)->dccpd_seq = seq;
563
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700564 dccp_transmit_skb(sk, skb);
565}
566
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800567EXPORT_SYMBOL_GPL(dccp_send_sync);
568
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300569/*
570 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
571 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
572 * any circumstances.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700573 */
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700574void dccp_send_close(struct sock *sk, const int active)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700575{
576 struct dccp_sock *dp = dccp_sk(sk);
577 struct sk_buff *skb;
Al Viro7d877f32005-10-21 03:20:43 -0400578 const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700579
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700580 skb = alloc_skb(sk->sk_prot->max_header, prio);
581 if (skb == NULL)
582 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700583
584 /* Reserve space for headers and prepare control bits. */
585 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300586 DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
587 DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700588
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700589 if (active) {
Ian McDonald97e58482006-08-26 19:16:45 -0700590 dccp_write_xmit(sk, 1);
Herbert Xu48918a42005-10-30 11:20:59 +1100591 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700592 dccp_transmit_skb(sk, skb_clone(skb, prio));
Ian McDonald97e58482006-08-26 19:16:45 -0700593 /* FIXME do we need a retransmit timer here? */
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700594 } else
595 dccp_transmit_skb(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700596}