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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
2 * net/dccp/output.c
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -02003 *
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07004 * 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 }
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +090090
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. Millere89862f2007-01-26 01:04:55 -0800127 err = icsk->icsk_af_ops->queue_xmit(skb, 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
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300178 */
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200179static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300180{
181 struct dccp_sock *dp = dccp_sk(sk);
182 DEFINE_WAIT(wait);
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200183 unsigned long delay;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300184 int rc;
185
186 while (1) {
187 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
188
Ian McDonald97e58482006-08-26 19:16:45 -0700189 if (sk->sk_err)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300190 goto do_error;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300191 if (signal_pending(current))
192 goto do_interrupted;
193
Gerrit Renker6b57c932006-11-28 19:55:06 -0200194 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300195 if (rc <= 0)
196 break;
197 delay = msecs_to_jiffies(rc);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300198 sk->sk_write_pending++;
199 release_sock(sk);
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200200 schedule_timeout(delay);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300201 lock_sock(sk);
202 sk->sk_write_pending--;
203 }
204out:
205 finish_wait(sk->sk_sleep, &wait);
206 return rc;
207
208do_error:
209 rc = -EPIPE;
210 goto out;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300211do_interrupted:
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200212 rc = -EINTR;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300213 goto out;
214}
215
Ian McDonald97e58482006-08-26 19:16:45 -0700216void dccp_write_xmit(struct sock *sk, int block)
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700217{
Ian McDonald97e58482006-08-26 19:16:45 -0700218 struct dccp_sock *dp = dccp_sk(sk);
219 struct sk_buff *skb;
Ian McDonald97e58482006-08-26 19:16:45 -0700220
221 while ((skb = skb_peek(&sk->sk_write_queue))) {
Gerrit Renker6b57c932006-11-28 19:55:06 -0200222 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300223
Ian McDonald97e58482006-08-26 19:16:45 -0700224 if (err > 0) {
225 if (!block) {
226 sk_reset_timer(sk, &dp->dccps_xmit_timer,
227 msecs_to_jiffies(err)+jiffies);
228 break;
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200229 } else
230 err = dccp_wait_for_ccid(sk, skb);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200231 if (err && err != -EINTR)
Gerrit Renker59348b12006-11-20 18:39:23 -0200232 DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
Ian McDonald97e58482006-08-26 19:16:45 -0700233 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700234
Ian McDonald97e58482006-08-26 19:16:45 -0700235 skb_dequeue(&sk->sk_write_queue);
236 if (err == 0) {
237 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
238 const int len = skb->len;
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700239
Ian McDonald97e58482006-08-26 19:16:45 -0700240 if (sk->sk_state == DCCP_PARTOPEN) {
241 /* See 8.1.5. Handshake Completion */
242 inet_csk_schedule_ack(sk);
243 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700244 inet_csk(sk)->icsk_rto,
245 DCCP_RTO_MAX);
Ian McDonald97e58482006-08-26 19:16:45 -0700246 dcb->dccpd_type = DCCP_PKT_DATAACK;
247 } else if (dccp_ack_pending(sk))
248 dcb->dccpd_type = DCCP_PKT_DATAACK;
249 else
250 dcb->dccpd_type = DCCP_PKT_DATA;
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700251
Ian McDonald97e58482006-08-26 19:16:45 -0700252 err = dccp_transmit_skb(sk, skb);
253 ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
Gerrit Renker59348b12006-11-20 18:39:23 -0200254 if (err)
255 DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
256 err);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200257 } else {
258 dccp_pr_debug("packet discarded\n");
Patrick McHardyb08d5842007-02-27 09:57:37 -0800259 kfree_skb(skb);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200260 }
Ian McDonald97e58482006-08-26 19:16:45 -0700261 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700262}
263
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700264int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
265{
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800266 if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700267 return -EHOSTUNREACH; /* Routing failure or similar. */
268
269 return dccp_transmit_skb(sk, (skb_cloned(skb) ?
270 pskb_copy(skb, GFP_ATOMIC):
271 skb_clone(skb, GFP_ATOMIC)));
272}
273
274struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
275 struct request_sock *req)
276{
277 struct dccp_hdr *dh;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700278 struct dccp_request_sock *dreq;
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800279 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700280 sizeof(struct dccp_hdr_ext) +
281 sizeof(struct dccp_hdr_response);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800282 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700283 GFP_ATOMIC);
284 if (skb == NULL)
285 return NULL;
286
287 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800288 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700289
290 skb->dst = dst_clone(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700291
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700292 dreq = dccp_rsk(req);
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200293 if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
294 dccp_inc_seqno(&dreq->dreq_iss);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700295 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700296 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800297
298 if (dccp_insert_options(sk, skb)) {
299 kfree_skb(skb);
300 return NULL;
301 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700302
Gerrit Renker09dbc382006-11-14 12:57:34 -0200303 /* Build and checksum header */
Gerrit Renker9b420782006-11-10 11:22:32 -0200304 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700305
306 dh->dccph_sport = inet_sk(sk)->sport;
307 dh->dccph_dport = inet_rsk(req)->rmt_port;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300308 dh->dccph_doff = (dccp_header_size +
309 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700310 dh->dccph_type = DCCP_PKT_RESPONSE;
311 dh->dccph_x = 1;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700312 dccp_hdr_set_seq(dh, dreq->dreq_iss);
313 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
314 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700315
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200316 dccp_csum_outgoing(skb);
317
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200318 /* We use `acked' to remember that a Response was already sent. */
319 inet_rsk(req)->acked = 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700320 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
321 return skb;
322}
323
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800324EXPORT_SYMBOL_GPL(dccp_make_response);
325
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800326static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
327 const enum dccp_reset_codes code)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700328{
329 struct dccp_hdr *dh;
330 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800331 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700332 sizeof(struct dccp_hdr_ext) +
333 sizeof(struct dccp_hdr_reset);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800334 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700335 GFP_ATOMIC);
336 if (skb == NULL)
337 return NULL;
338
339 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800340 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700341
342 skb->dst = dst_clone(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700343
344 dccp_inc_seqno(&dp->dccps_gss);
345
346 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
347 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
348 DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800349
350 if (dccp_insert_options(sk, skb)) {
351 kfree_skb(skb);
352 return NULL;
353 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700354
Gerrit Renker9b420782006-11-10 11:22:32 -0200355 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700356
357 dh->dccph_sport = inet_sk(sk)->sport;
358 dh->dccph_dport = inet_sk(sk)->dport;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300359 dh->dccph_doff = (dccp_header_size +
360 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700361 dh->dccph_type = DCCP_PKT_RESET;
362 dh->dccph_x = 1;
363 dccp_hdr_set_seq(dh, dp->dccps_gss);
364 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
365
366 dccp_hdr_reset(skb)->dccph_reset_code = code;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200367 inet_csk(sk)->icsk_af_ops->send_check(sk, 0, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700368
369 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
370 return skb;
371}
372
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800373int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
374{
375 /*
376 * FIXME: what if rebuild_header fails?
377 * Should we be doing a rebuild_header here?
378 */
379 int err = inet_sk_rebuild_header(sk);
380
381 if (err == 0) {
382 struct sk_buff *skb = dccp_make_reset(sk, sk->sk_dst_cache,
383 code);
384 if (skb != NULL) {
385 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
David S. Millere89862f2007-01-26 01:04:55 -0800386 err = inet_csk(sk)->icsk_af_ops->queue_xmit(skb, 0);
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200387 return net_xmit_eval(err);
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800388 }
389 }
390
391 return err;
392}
393
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700394/*
395 * Do all connect socket setups that can be done AF independent.
396 */
397static inline void dccp_connect_init(struct sock *sk)
398{
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800399 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700400 struct dst_entry *dst = __sk_dst_get(sk);
401 struct inet_connection_sock *icsk = inet_csk(sk);
402
403 sk->sk_err = 0;
404 sock_reset_flag(sk, SOCK_DONE);
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900405
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700406 dccp_sync_mss(sk, dst_mtu(dst));
407
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200408 /*
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800409 * SWL and AWL are initially adjusted so that they are not less than
410 * the initial Sequence Numbers received and sent, respectively:
411 * SWL := max(GSR + 1 - floor(W/4), ISR),
412 * AWL := max(GSS - W' + 1, ISS).
413 * These adjustments MUST be applied only at the beginning of the
414 * connection.
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200415 */
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200416 dccp_update_gss(sk, dp->dccps_iss);
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800417 dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700418
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200419 /* S.GAR - greatest valid acknowledgement number received on a non-Sync;
420 * initialized to S.ISS (sec. 8.5) */
421 dp->dccps_gar = dp->dccps_iss;
422
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700423 icsk->icsk_retransmits = 0;
424}
425
426int dccp_connect(struct sock *sk)
427{
428 struct sk_buff *skb;
429 struct inet_connection_sock *icsk = inet_csk(sk);
430
431 dccp_connect_init(sk);
432
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800433 skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700434 if (unlikely(skb == NULL))
435 return -ENOBUFS;
436
437 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800438 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700439
440 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700441
Herbert Xu48918a42005-10-30 11:20:59 +1100442 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700443 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
444 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
445
446 /* Timer for repeating the REQUEST until an answer. */
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700447 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
448 icsk->icsk_rto, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700449 return 0;
450}
451
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800452EXPORT_SYMBOL_GPL(dccp_connect);
453
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700454void dccp_send_ack(struct sock *sk)
455{
456 /* If we have been reset, we may not send again. */
457 if (sk->sk_state != DCCP_CLOSED) {
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800458 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
459 GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700460
461 if (skb == NULL) {
462 inet_csk_schedule_ack(sk);
463 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300464 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
465 TCP_DELACK_MAX,
466 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700467 return;
468 }
469
470 /* Reserve space for headers */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800471 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700472 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700473 dccp_transmit_skb(sk, skb);
474 }
475}
476
477EXPORT_SYMBOL_GPL(dccp_send_ack);
478
479void dccp_send_delayed_ack(struct sock *sk)
480{
481 struct inet_connection_sock *icsk = inet_csk(sk);
482 /*
483 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
484 * with using 2s, and active senders also piggyback the ACK into a
485 * DATAACK packet, so this is really for quiescent senders.
486 */
487 unsigned long timeout = jiffies + 2 * HZ;
488
489 /* Use new timeout only if there wasn't a older one earlier. */
490 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
491 /* If delack timer was blocked or is about to expire,
492 * send ACK now.
493 *
494 * FIXME: check the "about to expire" part
495 */
496 if (icsk->icsk_ack.blocked) {
497 dccp_send_ack(sk);
498 return;
499 }
500
501 if (!time_before(timeout, icsk->icsk_ack.timeout))
502 timeout = icsk->icsk_ack.timeout;
503 }
504 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
505 icsk->icsk_ack.timeout = timeout;
506 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
507}
508
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300509void dccp_send_sync(struct sock *sk, const u64 seq,
510 const enum dccp_pkt_type pkt_type)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700511{
512 /*
513 * We are not putting this on the write queue, so
514 * dccp_transmit_skb() will set the ownership to this
515 * sock.
516 */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800517 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700518
519 if (skb == NULL)
520 /* FIXME: how to make sure the sync is sent? */
521 return;
522
523 /* Reserve space for headers and prepare control bits. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800524 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300525 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700526 DCCP_SKB_CB(skb)->dccpd_seq = seq;
527
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700528 dccp_transmit_skb(sk, skb);
529}
530
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800531EXPORT_SYMBOL_GPL(dccp_send_sync);
532
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300533/*
534 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
535 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
536 * any circumstances.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700537 */
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700538void dccp_send_close(struct sock *sk, const int active)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700539{
540 struct dccp_sock *dp = dccp_sk(sk);
541 struct sk_buff *skb;
Al Viro7d877f32005-10-21 03:20:43 -0400542 const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700543
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700544 skb = alloc_skb(sk->sk_prot->max_header, prio);
545 if (skb == NULL)
546 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700547
548 /* Reserve space for headers and prepare control bits. */
549 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300550 DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
551 DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700552
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700553 if (active) {
Ian McDonald97e58482006-08-26 19:16:45 -0700554 dccp_write_xmit(sk, 1);
Herbert Xu48918a42005-10-30 11:20:59 +1100555 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700556 dccp_transmit_skb(sk, skb_clone(skb, prio));
Ian McDonald97e58482006-08-26 19:16:45 -0700557 /* FIXME do we need a retransmit timer here? */
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700558 } else
559 dccp_transmit_skb(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700560}