blob: f49544618f2007857dcf31c59512e5d1d2faca2c [file] [log] [blame]
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
Herbert Xu49c5bfa2005-10-18 12:03:28 +1000129 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
David S. Millere89862f2007-01-26 01:04:55 -0800130 err = icsk->icsk_af_ops->queue_xmit(skb, 0);
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200131 return net_xmit_eval(err);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700132 }
133 return -ENOBUFS;
134}
135
136unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
137{
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800138 struct inet_connection_sock *icsk = inet_csk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700139 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800140 int mss_now = (pmtu - icsk->icsk_af_ops->net_header_len -
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800141 sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700142
143 /* Now subtract optional transport overhead */
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800144 mss_now -= icsk->icsk_ext_hdr_len;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700145
146 /*
147 * FIXME: this should come from the CCID infrastructure, where, say,
148 * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
149 * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
150 * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
151 * make it a multiple of 4
152 */
153
154 mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
155
156 /* And store cached results */
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800157 icsk->icsk_pmtu_cookie = pmtu;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700158 dp->dccps_mss_cache = mss_now;
159
160 return mss_now;
161}
162
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800163EXPORT_SYMBOL_GPL(dccp_sync_mss);
164
Arnaldo Carvalho de Meloc530cfb2005-08-29 02:15:54 -0300165void dccp_write_space(struct sock *sk)
166{
167 read_lock(&sk->sk_callback_lock);
168
169 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
170 wake_up_interruptible(sk->sk_sleep);
171 /* Should agree with poll, otherwise some programs break */
172 if (sock_writeable(sk))
173 sk_wake_async(sk, 2, POLL_OUT);
174
175 read_unlock(&sk->sk_callback_lock);
176}
177
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300178/**
179 * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
Gerrit Renkerbc849872007-10-04 14:38:49 -0700180 * @sk: socket to wait for
181 * @skb: current skb to pass on for waiting
182 * @delay: sleep timeout in milliseconds (> 0)
183 * This function is called by default when the socket is closed, and
184 * when a non-zero linger time is set on the socket. For consistency
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300185 */
Gerrit Renkerbc849872007-10-04 14:38:49 -0700186static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300187{
188 struct dccp_sock *dp = dccp_sk(sk);
189 DEFINE_WAIT(wait);
Gerrit Renkerbc849872007-10-04 14:38:49 -0700190 unsigned long jiffdelay;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300191 int rc;
192
Gerrit Renkerbc849872007-10-04 14:38:49 -0700193 do {
194 dccp_pr_debug("delayed send by %d msec\n", delay);
195 jiffdelay = msecs_to_jiffies(delay);
196
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300197 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
198
Gerrit Renkerbc849872007-10-04 14:38:49 -0700199 sk->sk_write_pending++;
200 release_sock(sk);
201 schedule_timeout(jiffdelay);
202 lock_sock(sk);
203 sk->sk_write_pending--;
204
Ian McDonald97e58482006-08-26 19:16:45 -0700205 if (sk->sk_err)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300206 goto do_error;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300207 if (signal_pending(current))
208 goto do_interrupted;
209
Gerrit Renker6b57c932006-11-28 19:55:06 -0200210 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
Gerrit Renkerbc849872007-10-04 14:38:49 -0700211 } while ((delay = rc) > 0);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300212out:
213 finish_wait(sk->sk_sleep, &wait);
214 return rc;
215
216do_error:
217 rc = -EPIPE;
218 goto out;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300219do_interrupted:
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200220 rc = -EINTR;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300221 goto out;
222}
223
Ian McDonald97e58482006-08-26 19:16:45 -0700224void dccp_write_xmit(struct sock *sk, int block)
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700225{
Ian McDonald97e58482006-08-26 19:16:45 -0700226 struct dccp_sock *dp = dccp_sk(sk);
227 struct sk_buff *skb;
Ian McDonald97e58482006-08-26 19:16:45 -0700228
229 while ((skb = skb_peek(&sk->sk_write_queue))) {
Gerrit Renker6b57c932006-11-28 19:55:06 -0200230 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300231
Ian McDonald97e58482006-08-26 19:16:45 -0700232 if (err > 0) {
233 if (!block) {
234 sk_reset_timer(sk, &dp->dccps_xmit_timer,
235 msecs_to_jiffies(err)+jiffies);
236 break;
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200237 } else
Gerrit Renkerbc849872007-10-04 14:38:49 -0700238 err = dccp_wait_for_ccid(sk, skb, err);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200239 if (err && err != -EINTR)
Gerrit Renker59348b12006-11-20 18:39:23 -0200240 DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
Ian McDonald97e58482006-08-26 19:16:45 -0700241 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700242
Ian McDonald97e58482006-08-26 19:16:45 -0700243 skb_dequeue(&sk->sk_write_queue);
244 if (err == 0) {
245 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
246 const int len = skb->len;
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700247
Ian McDonald97e58482006-08-26 19:16:45 -0700248 if (sk->sk_state == DCCP_PARTOPEN) {
249 /* See 8.1.5. Handshake Completion */
250 inet_csk_schedule_ack(sk);
251 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700252 inet_csk(sk)->icsk_rto,
253 DCCP_RTO_MAX);
Ian McDonald97e58482006-08-26 19:16:45 -0700254 dcb->dccpd_type = DCCP_PKT_DATAACK;
255 } else if (dccp_ack_pending(sk))
256 dcb->dccpd_type = DCCP_PKT_DATAACK;
257 else
258 dcb->dccpd_type = DCCP_PKT_DATA;
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700259
Ian McDonald97e58482006-08-26 19:16:45 -0700260 err = dccp_transmit_skb(sk, skb);
261 ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
Gerrit Renker59348b12006-11-20 18:39:23 -0200262 if (err)
263 DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
264 err);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200265 } else {
Gerrit Renker6626e362007-03-20 15:00:28 -0300266 dccp_pr_debug("packet discarded due to err=%d\n", err);
Patrick McHardyb08d5842007-02-27 09:57:37 -0800267 kfree_skb(skb);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200268 }
Ian McDonald97e58482006-08-26 19:16:45 -0700269 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700270}
271
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700272int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
273{
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800274 if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700275 return -EHOSTUNREACH; /* Routing failure or similar. */
276
277 return dccp_transmit_skb(sk, (skb_cloned(skb) ?
278 pskb_copy(skb, GFP_ATOMIC):
279 skb_clone(skb, GFP_ATOMIC)));
280}
281
282struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
283 struct request_sock *req)
284{
285 struct dccp_hdr *dh;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700286 struct dccp_request_sock *dreq;
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800287 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700288 sizeof(struct dccp_hdr_ext) +
289 sizeof(struct dccp_hdr_response);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800290 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700291 GFP_ATOMIC);
292 if (skb == NULL)
293 return NULL;
294
295 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800296 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700297
298 skb->dst = dst_clone(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700299
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700300 dreq = dccp_rsk(req);
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200301 if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
302 dccp_inc_seqno(&dreq->dreq_iss);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700303 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700304 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800305
306 if (dccp_insert_options(sk, skb)) {
307 kfree_skb(skb);
308 return NULL;
309 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700310
Gerrit Renker09dbc382006-11-14 12:57:34 -0200311 /* Build and checksum header */
Gerrit Renker9b420782006-11-10 11:22:32 -0200312 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700313
314 dh->dccph_sport = inet_sk(sk)->sport;
315 dh->dccph_dport = inet_rsk(req)->rmt_port;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300316 dh->dccph_doff = (dccp_header_size +
317 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700318 dh->dccph_type = DCCP_PKT_RESPONSE;
319 dh->dccph_x = 1;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700320 dccp_hdr_set_seq(dh, dreq->dreq_iss);
321 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
322 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700323
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200324 dccp_csum_outgoing(skb);
325
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200326 /* We use `acked' to remember that a Response was already sent. */
327 inet_rsk(req)->acked = 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700328 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
329 return skb;
330}
331
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800332EXPORT_SYMBOL_GPL(dccp_make_response);
333
Gerrit Renkere356d372007-09-26 14:35:19 -0300334/* answer offending packet in @rcv_skb with Reset from control socket @ctl */
335struct sk_buff *dccp_ctl_make_reset(struct socket *ctl, struct sk_buff *rcv_skb)
336{
337 struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh;
338 struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb);
339 const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
340 sizeof(struct dccp_hdr_ext) +
341 sizeof(struct dccp_hdr_reset);
342 struct dccp_hdr_reset *dhr;
343 struct sk_buff *skb;
344
345 skb = alloc_skb(ctl->sk->sk_prot->max_header, GFP_ATOMIC);
346 if (skb == NULL)
347 return NULL;
348
349 skb_reserve(skb, ctl->sk->sk_prot->max_header);
350
351 /* Swap the send and the receive. */
352 dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
353 dh->dccph_type = DCCP_PKT_RESET;
354 dh->dccph_sport = rxdh->dccph_dport;
355 dh->dccph_dport = rxdh->dccph_sport;
356 dh->dccph_doff = dccp_hdr_reset_len / 4;
357 dh->dccph_x = 1;
358
359 dhr = dccp_hdr_reset(skb);
360 dhr->dccph_reset_code = dcb->dccpd_reset_code;
361
362 switch (dcb->dccpd_reset_code) {
363 case DCCP_RESET_CODE_PACKET_ERROR:
364 dhr->dccph_reset_data[0] = rxdh->dccph_type;
365 break;
366 case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */
367 case DCCP_RESET_CODE_MANDATORY_ERROR:
368 memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);
369 break;
370 }
371 /*
372 * From RFC 4340, 8.3.1:
373 * If P.ackno exists, set R.seqno := P.ackno + 1.
374 * Else set R.seqno := 0.
375 */
376 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
377 dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));
378 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);
379
380 dccp_csum_outgoing(skb);
381 return skb;
382}
383
384EXPORT_SYMBOL_GPL(dccp_ctl_make_reset);
385
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300386/* send Reset on established socket, to close or abort the connection */
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800387int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
388{
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300389 struct sk_buff *skb;
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800390 /*
391 * FIXME: what if rebuild_header fails?
392 * Should we be doing a rebuild_header here?
393 */
394 int err = inet_sk_rebuild_header(sk);
395
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300396 if (err != 0)
397 return err;
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800398
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300399 skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC);
400 if (skb == NULL)
401 return -ENOBUFS;
402
403 /* Reserve space for headers and prepare control bits. */
404 skb_reserve(skb, sk->sk_prot->max_header);
405 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
406 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
407
408 return dccp_transmit_skb(sk, skb);
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800409}
410
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700411/*
412 * Do all connect socket setups that can be done AF independent.
413 */
414static inline void dccp_connect_init(struct sock *sk)
415{
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800416 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700417 struct dst_entry *dst = __sk_dst_get(sk);
418 struct inet_connection_sock *icsk = inet_csk(sk);
419
420 sk->sk_err = 0;
421 sock_reset_flag(sk, SOCK_DONE);
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900422
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700423 dccp_sync_mss(sk, dst_mtu(dst));
424
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200425 /*
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800426 * SWL and AWL are initially adjusted so that they are not less than
427 * the initial Sequence Numbers received and sent, respectively:
428 * SWL := max(GSR + 1 - floor(W/4), ISR),
429 * AWL := max(GSS - W' + 1, ISS).
430 * These adjustments MUST be applied only at the beginning of the
431 * connection.
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200432 */
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200433 dccp_update_gss(sk, dp->dccps_iss);
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800434 dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700435
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200436 /* S.GAR - greatest valid acknowledgement number received on a non-Sync;
437 * initialized to S.ISS (sec. 8.5) */
438 dp->dccps_gar = dp->dccps_iss;
439
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700440 icsk->icsk_retransmits = 0;
441}
442
443int dccp_connect(struct sock *sk)
444{
445 struct sk_buff *skb;
446 struct inet_connection_sock *icsk = inet_csk(sk);
447
448 dccp_connect_init(sk);
449
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800450 skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700451 if (unlikely(skb == NULL))
452 return -ENOBUFS;
453
454 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800455 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700456
457 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700458
Herbert Xu48918a42005-10-30 11:20:59 +1100459 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700460 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
461 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
462
463 /* Timer for repeating the REQUEST until an answer. */
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700464 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
465 icsk->icsk_rto, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700466 return 0;
467}
468
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800469EXPORT_SYMBOL_GPL(dccp_connect);
470
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700471void dccp_send_ack(struct sock *sk)
472{
473 /* If we have been reset, we may not send again. */
474 if (sk->sk_state != DCCP_CLOSED) {
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800475 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
476 GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700477
478 if (skb == NULL) {
479 inet_csk_schedule_ack(sk);
480 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300481 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
482 TCP_DELACK_MAX,
483 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700484 return;
485 }
486
487 /* Reserve space for headers */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800488 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700489 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700490 dccp_transmit_skb(sk, skb);
491 }
492}
493
494EXPORT_SYMBOL_GPL(dccp_send_ack);
495
Gerrit Renker727ecc52007-09-26 11:26:04 -0300496/* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700497void dccp_send_delayed_ack(struct sock *sk)
498{
499 struct inet_connection_sock *icsk = inet_csk(sk);
500 /*
501 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
502 * with using 2s, and active senders also piggyback the ACK into a
503 * DATAACK packet, so this is really for quiescent senders.
504 */
505 unsigned long timeout = jiffies + 2 * HZ;
506
507 /* Use new timeout only if there wasn't a older one earlier. */
508 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
509 /* If delack timer was blocked or is about to expire,
510 * send ACK now.
511 *
512 * FIXME: check the "about to expire" part
513 */
514 if (icsk->icsk_ack.blocked) {
515 dccp_send_ack(sk);
516 return;
517 }
518
519 if (!time_before(timeout, icsk->icsk_ack.timeout))
520 timeout = icsk->icsk_ack.timeout;
521 }
522 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
523 icsk->icsk_ack.timeout = timeout;
524 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
525}
526
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700527void dccp_send_sync(struct sock *sk, const u64 ackno,
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300528 const enum dccp_pkt_type pkt_type)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700529{
530 /*
531 * We are not putting this on the write queue, so
532 * dccp_transmit_skb() will set the ownership to this
533 * sock.
534 */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800535 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700536
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700537 if (skb == NULL) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700538 /* FIXME: how to make sure the sync is sent? */
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700539 DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700540 return;
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700541 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700542
543 /* Reserve space for headers and prepare control bits. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800544 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300545 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700546 DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700547
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700548 dccp_transmit_skb(sk, skb);
549}
550
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800551EXPORT_SYMBOL_GPL(dccp_send_sync);
552
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300553/*
554 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
555 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
556 * any circumstances.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700557 */
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700558void dccp_send_close(struct sock *sk, const int active)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700559{
560 struct dccp_sock *dp = dccp_sk(sk);
561 struct sk_buff *skb;
Al Viro7d877f32005-10-21 03:20:43 -0400562 const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700563
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700564 skb = alloc_skb(sk->sk_prot->max_header, prio);
565 if (skb == NULL)
566 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700567
568 /* Reserve space for headers and prepare control bits. */
569 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300570 DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
571 DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700572
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700573 if (active) {
Ian McDonald97e58482006-08-26 19:16:45 -0700574 dccp_write_xmit(sk, 1);
Herbert Xu48918a42005-10-30 11:20:59 +1100575 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700576 dccp_transmit_skb(sk, skb_clone(skb, prio));
Ian McDonald97e58482006-08-26 19:16:45 -0700577 /* FIXME do we need a retransmit timer here? */
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700578 } else
579 dccp_transmit_skb(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700580}