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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:
Gerrit Renkeree1a1592007-09-26 11:30:02 -030064 case DCCP_PKT_RESET:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070065 break;
Herbert Xuedc9e812005-10-30 11:20:59 +110066
Andrea Bittauafe00252006-03-20 17:43:56 -080067 case DCCP_PKT_REQUEST:
68 set_ack = 0;
69 /* fall through */
70
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070071 case DCCP_PKT_SYNC:
72 case DCCP_PKT_SYNCACK:
Gerrit Renkerb0d045c2007-09-25 22:42:27 -070073 ackno = dcb->dccpd_ack_seq;
Herbert Xuedc9e812005-10-30 11:20:59 +110074 /* fall through */
75 default:
76 /*
Gerrit Renkeree1a1592007-09-26 11:30:02 -030077 * Set owner/destructor: some skbs are allocated via
78 * alloc_skb (e.g. when retransmission may happen).
79 * Only Data, DataAck, and Reset packets should come
80 * through here with skb->sk set.
Herbert Xuedc9e812005-10-30 11:20:59 +110081 */
82 WARN_ON(skb->sk);
83 skb_set_owner_w(skb, sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070084 break;
85 }
Arnaldo Carvalho de Melo24117722005-08-21 05:40:16 -030086
87 dcb->dccpd_seq = dp->dccps_gss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -080088
89 if (dccp_insert_options(sk, skb)) {
90 kfree_skb(skb);
91 return -EPROTO;
92 }
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +090093
Herbert Xufda0fd62005-10-14 16:38:49 +100094
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070095 /* Build DCCP header and checksum it. */
Gerrit Renker9b420782006-11-10 11:22:32 -020096 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070097 dh->dccph_type = dcb->dccpd_type;
98 dh->dccph_sport = inet->sport;
99 dh->dccph_dport = inet->dport;
100 dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
101 dh->dccph_ccval = dcb->dccpd_ccval;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200102 dh->dccph_cscov = dp->dccps_pcslen;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700103 /* XXX For now we're using only 48 bits sequence numbers */
104 dh->dccph_x = 1;
105
106 dp->dccps_awh = dp->dccps_gss;
107 dccp_hdr_set_seq(dh, dp->dccps_gss);
108 if (set_ack)
109 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
110
111 switch (dcb->dccpd_type) {
112 case DCCP_PKT_REQUEST:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300113 dccp_hdr_request(skb)->dccph_req_service =
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700114 dp->dccps_service;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700115 break;
116 case DCCP_PKT_RESET:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300117 dccp_hdr_reset(skb)->dccph_reset_code =
118 dcb->dccpd_reset_code;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700119 break;
120 }
121
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200122 icsk->icsk_af_ops->send_check(sk, 0, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700123
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700124 if (set_ack)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700125 dccp_event_ack_sent(sk);
126
127 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
128
David S. Millere89862f2007-01-26 01:04:55 -0800129 err = icsk->icsk_af_ops->queue_xmit(skb, 0);
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200130 return net_xmit_eval(err);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700131 }
132 return -ENOBUFS;
133}
134
Gerrit Renker61799832007-12-13 23:37:55 -0200135/**
136 * dccp_determine_ccmps - Find out about CCID-specfic packet-size limits
137 * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.),
138 * since the RX CCID is restricted to feedback packets (Acks), which are small
139 * in comparison with the data traffic. A value of 0 means "no current CCMPS".
140 */
141static u32 dccp_determine_ccmps(const struct dccp_sock *dp)
142{
143 const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid;
144
145 if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL)
146 return 0;
147 return tx_ccid->ccid_ops->ccid_ccmps;
148}
149
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700150unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
151{
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800152 struct inet_connection_sock *icsk = inet_csk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700153 struct dccp_sock *dp = dccp_sk(sk);
Gerrit Renker61799832007-12-13 23:37:55 -0200154 u32 ccmps = dccp_determine_ccmps(dp);
155 int cur_mps = ccmps ? min(pmtu, ccmps) : pmtu;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700156
Gerrit Renker61799832007-12-13 23:37:55 -0200157 /* Account for header lengths and IPv4/v6 option overhead */
158 cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len +
159 sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700160
161 /*
162 * FIXME: this should come from the CCID infrastructure, where, say,
163 * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
164 * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
165 * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
166 * make it a multiple of 4
167 */
168
Gerrit Renker61799832007-12-13 23:37:55 -0200169 cur_mps -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700170
171 /* And store cached results */
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800172 icsk->icsk_pmtu_cookie = pmtu;
Gerrit Renker61799832007-12-13 23:37:55 -0200173 dp->dccps_mss_cache = cur_mps;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700174
Gerrit Renker61799832007-12-13 23:37:55 -0200175 return cur_mps;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700176}
177
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800178EXPORT_SYMBOL_GPL(dccp_sync_mss);
179
Arnaldo Carvalho de Meloc530cfb2005-08-29 02:15:54 -0300180void dccp_write_space(struct sock *sk)
181{
182 read_lock(&sk->sk_callback_lock);
183
184 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
185 wake_up_interruptible(sk->sk_sleep);
186 /* Should agree with poll, otherwise some programs break */
187 if (sock_writeable(sk))
Pavel Emelyanov8d8ad9d2007-11-26 20:10:50 +0800188 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
Arnaldo Carvalho de Meloc530cfb2005-08-29 02:15:54 -0300189
190 read_unlock(&sk->sk_callback_lock);
191}
192
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300193/**
194 * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
Gerrit Renkerbc849872007-10-04 14:38:49 -0700195 * @sk: socket to wait for
196 * @skb: current skb to pass on for waiting
197 * @delay: sleep timeout in milliseconds (> 0)
198 * This function is called by default when the socket is closed, and
199 * when a non-zero linger time is set on the socket. For consistency
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300200 */
Gerrit Renkerbc849872007-10-04 14:38:49 -0700201static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300202{
203 struct dccp_sock *dp = dccp_sk(sk);
204 DEFINE_WAIT(wait);
Gerrit Renkerbc849872007-10-04 14:38:49 -0700205 unsigned long jiffdelay;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300206 int rc;
207
Gerrit Renkerbc849872007-10-04 14:38:49 -0700208 do {
209 dccp_pr_debug("delayed send by %d msec\n", delay);
210 jiffdelay = msecs_to_jiffies(delay);
211
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300212 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
213
Gerrit Renkerbc849872007-10-04 14:38:49 -0700214 sk->sk_write_pending++;
215 release_sock(sk);
216 schedule_timeout(jiffdelay);
217 lock_sock(sk);
218 sk->sk_write_pending--;
219
Ian McDonald97e58482006-08-26 19:16:45 -0700220 if (sk->sk_err)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300221 goto do_error;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300222 if (signal_pending(current))
223 goto do_interrupted;
224
Gerrit Renker6b57c932006-11-28 19:55:06 -0200225 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
Gerrit Renkerbc849872007-10-04 14:38:49 -0700226 } while ((delay = rc) > 0);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300227out:
228 finish_wait(sk->sk_sleep, &wait);
229 return rc;
230
231do_error:
232 rc = -EPIPE;
233 goto out;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300234do_interrupted:
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200235 rc = -EINTR;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300236 goto out;
237}
238
Ian McDonald97e58482006-08-26 19:16:45 -0700239void dccp_write_xmit(struct sock *sk, int block)
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700240{
Ian McDonald97e58482006-08-26 19:16:45 -0700241 struct dccp_sock *dp = dccp_sk(sk);
242 struct sk_buff *skb;
Ian McDonald97e58482006-08-26 19:16:45 -0700243
244 while ((skb = skb_peek(&sk->sk_write_queue))) {
Gerrit Renker6b57c932006-11-28 19:55:06 -0200245 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300246
Ian McDonald97e58482006-08-26 19:16:45 -0700247 if (err > 0) {
248 if (!block) {
249 sk_reset_timer(sk, &dp->dccps_xmit_timer,
250 msecs_to_jiffies(err)+jiffies);
251 break;
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200252 } else
Gerrit Renkerbc849872007-10-04 14:38:49 -0700253 err = dccp_wait_for_ccid(sk, skb, err);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200254 if (err && err != -EINTR)
Gerrit Renker59348b12006-11-20 18:39:23 -0200255 DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
Ian McDonald97e58482006-08-26 19:16:45 -0700256 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700257
Ian McDonald97e58482006-08-26 19:16:45 -0700258 skb_dequeue(&sk->sk_write_queue);
259 if (err == 0) {
260 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
261 const int len = skb->len;
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700262
Ian McDonald97e58482006-08-26 19:16:45 -0700263 if (sk->sk_state == DCCP_PARTOPEN) {
264 /* See 8.1.5. Handshake Completion */
265 inet_csk_schedule_ack(sk);
266 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700267 inet_csk(sk)->icsk_rto,
268 DCCP_RTO_MAX);
Ian McDonald97e58482006-08-26 19:16:45 -0700269 dcb->dccpd_type = DCCP_PKT_DATAACK;
270 } else if (dccp_ack_pending(sk))
271 dcb->dccpd_type = DCCP_PKT_DATAACK;
272 else
273 dcb->dccpd_type = DCCP_PKT_DATA;
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700274
Ian McDonald97e58482006-08-26 19:16:45 -0700275 err = dccp_transmit_skb(sk, skb);
276 ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
Gerrit Renker59348b12006-11-20 18:39:23 -0200277 if (err)
278 DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
279 err);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200280 } else {
Gerrit Renker6626e362007-03-20 15:00:28 -0300281 dccp_pr_debug("packet discarded due to err=%d\n", err);
Patrick McHardyb08d5842007-02-27 09:57:37 -0800282 kfree_skb(skb);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200283 }
Ian McDonald97e58482006-08-26 19:16:45 -0700284 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700285}
286
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700287int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
288{
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800289 if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700290 return -EHOSTUNREACH; /* Routing failure or similar. */
291
292 return dccp_transmit_skb(sk, (skb_cloned(skb) ?
293 pskb_copy(skb, GFP_ATOMIC):
294 skb_clone(skb, GFP_ATOMIC)));
295}
296
297struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
298 struct request_sock *req)
299{
300 struct dccp_hdr *dh;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700301 struct dccp_request_sock *dreq;
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800302 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700303 sizeof(struct dccp_hdr_ext) +
304 sizeof(struct dccp_hdr_response);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800305 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700306 GFP_ATOMIC);
307 if (skb == NULL)
308 return NULL;
309
310 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800311 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700312
313 skb->dst = dst_clone(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700314
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700315 dreq = dccp_rsk(req);
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200316 if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
317 dccp_inc_seqno(&dreq->dreq_iss);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700318 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700319 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800320
Gerrit Renkeraf3b8672007-12-13 12:38:11 -0200321 if (dccp_insert_options_rsk(dreq, skb)) {
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800322 kfree_skb(skb);
323 return NULL;
324 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700325
Gerrit Renker09dbc382006-11-14 12:57:34 -0200326 /* Build and checksum header */
Gerrit Renker9b420782006-11-10 11:22:32 -0200327 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700328
329 dh->dccph_sport = inet_sk(sk)->sport;
330 dh->dccph_dport = inet_rsk(req)->rmt_port;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300331 dh->dccph_doff = (dccp_header_size +
332 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700333 dh->dccph_type = DCCP_PKT_RESPONSE;
334 dh->dccph_x = 1;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700335 dccp_hdr_set_seq(dh, dreq->dreq_iss);
336 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
337 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700338
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200339 dccp_csum_outgoing(skb);
340
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200341 /* We use `acked' to remember that a Response was already sent. */
342 inet_rsk(req)->acked = 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700343 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
344 return skb;
345}
346
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800347EXPORT_SYMBOL_GPL(dccp_make_response);
348
Gerrit Renkere356d372007-09-26 14:35:19 -0300349/* answer offending packet in @rcv_skb with Reset from control socket @ctl */
350struct sk_buff *dccp_ctl_make_reset(struct socket *ctl, struct sk_buff *rcv_skb)
351{
352 struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh;
353 struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb);
354 const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
355 sizeof(struct dccp_hdr_ext) +
356 sizeof(struct dccp_hdr_reset);
357 struct dccp_hdr_reset *dhr;
358 struct sk_buff *skb;
359
360 skb = alloc_skb(ctl->sk->sk_prot->max_header, GFP_ATOMIC);
361 if (skb == NULL)
362 return NULL;
363
364 skb_reserve(skb, ctl->sk->sk_prot->max_header);
365
366 /* Swap the send and the receive. */
367 dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
368 dh->dccph_type = DCCP_PKT_RESET;
369 dh->dccph_sport = rxdh->dccph_dport;
370 dh->dccph_dport = rxdh->dccph_sport;
371 dh->dccph_doff = dccp_hdr_reset_len / 4;
372 dh->dccph_x = 1;
373
374 dhr = dccp_hdr_reset(skb);
375 dhr->dccph_reset_code = dcb->dccpd_reset_code;
376
377 switch (dcb->dccpd_reset_code) {
378 case DCCP_RESET_CODE_PACKET_ERROR:
379 dhr->dccph_reset_data[0] = rxdh->dccph_type;
380 break;
381 case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */
382 case DCCP_RESET_CODE_MANDATORY_ERROR:
383 memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);
384 break;
385 }
386 /*
387 * From RFC 4340, 8.3.1:
388 * If P.ackno exists, set R.seqno := P.ackno + 1.
389 * Else set R.seqno := 0.
390 */
391 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
392 dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));
393 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);
394
395 dccp_csum_outgoing(skb);
396 return skb;
397}
398
399EXPORT_SYMBOL_GPL(dccp_ctl_make_reset);
400
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300401/* send Reset on established socket, to close or abort the connection */
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800402int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
403{
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300404 struct sk_buff *skb;
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800405 /*
406 * FIXME: what if rebuild_header fails?
407 * Should we be doing a rebuild_header here?
408 */
Gerrit Renkerf53dc672007-11-28 08:35:08 +0000409 int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk);
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800410
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300411 if (err != 0)
412 return err;
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800413
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300414 skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC);
415 if (skb == NULL)
416 return -ENOBUFS;
417
418 /* Reserve space for headers and prepare control bits. */
419 skb_reserve(skb, sk->sk_prot->max_header);
420 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
421 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
422
423 return dccp_transmit_skb(sk, skb);
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800424}
425
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700426/*
427 * Do all connect socket setups that can be done AF independent.
428 */
429static inline void dccp_connect_init(struct sock *sk)
430{
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800431 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700432 struct dst_entry *dst = __sk_dst_get(sk);
433 struct inet_connection_sock *icsk = inet_csk(sk);
434
435 sk->sk_err = 0;
436 sock_reset_flag(sk, SOCK_DONE);
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900437
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700438 dccp_sync_mss(sk, dst_mtu(dst));
439
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200440 /*
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800441 * SWL and AWL are initially adjusted so that they are not less than
442 * the initial Sequence Numbers received and sent, respectively:
443 * SWL := max(GSR + 1 - floor(W/4), ISR),
444 * AWL := max(GSS - W' + 1, ISS).
445 * These adjustments MUST be applied only at the beginning of the
446 * connection.
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200447 */
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200448 dccp_update_gss(sk, dp->dccps_iss);
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800449 dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700450
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200451 /* S.GAR - greatest valid acknowledgement number received on a non-Sync;
452 * initialized to S.ISS (sec. 8.5) */
453 dp->dccps_gar = dp->dccps_iss;
454
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700455 icsk->icsk_retransmits = 0;
456}
457
458int dccp_connect(struct sock *sk)
459{
460 struct sk_buff *skb;
461 struct inet_connection_sock *icsk = inet_csk(sk);
462
463 dccp_connect_init(sk);
464
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800465 skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700466 if (unlikely(skb == NULL))
467 return -ENOBUFS;
468
469 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800470 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700471
472 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700473
Herbert Xu48918a42005-10-30 11:20:59 +1100474 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700475 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
476 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
477
478 /* Timer for repeating the REQUEST until an answer. */
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700479 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
480 icsk->icsk_rto, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700481 return 0;
482}
483
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800484EXPORT_SYMBOL_GPL(dccp_connect);
485
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700486void dccp_send_ack(struct sock *sk)
487{
488 /* If we have been reset, we may not send again. */
489 if (sk->sk_state != DCCP_CLOSED) {
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800490 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
491 GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700492
493 if (skb == NULL) {
494 inet_csk_schedule_ack(sk);
495 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300496 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
497 TCP_DELACK_MAX,
498 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700499 return;
500 }
501
502 /* Reserve space for headers */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800503 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700504 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700505 dccp_transmit_skb(sk, skb);
506 }
507}
508
509EXPORT_SYMBOL_GPL(dccp_send_ack);
510
Gerrit Renker727ecc52007-09-26 11:26:04 -0300511/* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700512void dccp_send_delayed_ack(struct sock *sk)
513{
514 struct inet_connection_sock *icsk = inet_csk(sk);
515 /*
516 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
517 * with using 2s, and active senders also piggyback the ACK into a
518 * DATAACK packet, so this is really for quiescent senders.
519 */
520 unsigned long timeout = jiffies + 2 * HZ;
521
522 /* Use new timeout only if there wasn't a older one earlier. */
523 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
524 /* If delack timer was blocked or is about to expire,
525 * send ACK now.
526 *
527 * FIXME: check the "about to expire" part
528 */
529 if (icsk->icsk_ack.blocked) {
530 dccp_send_ack(sk);
531 return;
532 }
533
534 if (!time_before(timeout, icsk->icsk_ack.timeout))
535 timeout = icsk->icsk_ack.timeout;
536 }
537 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
538 icsk->icsk_ack.timeout = timeout;
539 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
540}
541
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700542void dccp_send_sync(struct sock *sk, const u64 ackno,
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300543 const enum dccp_pkt_type pkt_type)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700544{
545 /*
546 * We are not putting this on the write queue, so
547 * dccp_transmit_skb() will set the ownership to this
548 * sock.
549 */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800550 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700551
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700552 if (skb == NULL) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700553 /* FIXME: how to make sure the sync is sent? */
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700554 DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700555 return;
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700556 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700557
558 /* Reserve space for headers and prepare control bits. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800559 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300560 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700561 DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700562
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700563 dccp_transmit_skb(sk, skb);
564}
565
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800566EXPORT_SYMBOL_GPL(dccp_send_sync);
567
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300568/*
569 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
570 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
571 * any circumstances.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700572 */
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700573void dccp_send_close(struct sock *sk, const int active)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700574{
575 struct dccp_sock *dp = dccp_sk(sk);
576 struct sk_buff *skb;
Al Viro7d877f32005-10-21 03:20:43 -0400577 const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700578
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700579 skb = alloc_skb(sk->sk_prot->max_header, prio);
580 if (skb == NULL)
581 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700582
583 /* Reserve space for headers and prepare control bits. */
584 skb_reserve(skb, sk->sk_prot->max_header);
Gerrit Renkerb8599d22007-12-13 12:25:01 -0200585 if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait)
586 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ;
587 else
588 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700589
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700590 if (active) {
Ian McDonald97e58482006-08-26 19:16:45 -0700591 dccp_write_xmit(sk, 1);
Herbert Xu48918a42005-10-30 11:20:59 +1100592 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700593 dccp_transmit_skb(sk, skb_clone(skb, prio));
Gerrit Renker92d31922007-12-13 12:02:43 -0200594 /*
595 * Retransmission timer for active-close: RFC 4340, 8.3 requires
596 * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ
597 * state can be left. The initial timeout is 2 RTTs.
598 * Since RTT measurement is done by the CCIDs, there is no easy
599 * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4
600 * is too low (200ms); we use a high value to avoid unnecessary
601 * retransmissions when the link RTT is > 0.2 seconds.
602 * FIXME: Let main module sample RTTs and use that instead.
603 */
604 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
605 DCCP_TIMEOUT_INIT, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700606 } else
607 dccp_transmit_skb(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700608}