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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;
Gerrit Renker73f18fd2008-07-26 11:59:10 +010056 /*
57 * Increment GSS here already in case the option code needs it.
58 * Update GSS for real only if option processing below succeeds.
59 */
60 dcb->dccpd_seq = ADD48(dp->dccps_gss, 1);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070061
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070062 switch (dcb->dccpd_type) {
63 case DCCP_PKT_DATA:
64 set_ack = 0;
Herbert Xuedc9e812005-10-30 11:20:59 +110065 /* fall through */
66 case DCCP_PKT_DATAACK:
Gerrit Renkeree1a1592007-09-26 11:30:02 -030067 case DCCP_PKT_RESET:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070068 break;
Herbert Xuedc9e812005-10-30 11:20:59 +110069
Andrea Bittauafe00252006-03-20 17:43:56 -080070 case DCCP_PKT_REQUEST:
71 set_ack = 0;
Gerrit Renker73f18fd2008-07-26 11:59:10 +010072 /* Use ISS on the first (non-retransmitted) Request. */
73 if (icsk->icsk_retransmits == 0)
74 dcb->dccpd_seq = dp->dccps_iss;
Andrea Bittauafe00252006-03-20 17:43:56 -080075 /* fall through */
76
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070077 case DCCP_PKT_SYNC:
78 case DCCP_PKT_SYNCACK:
Gerrit Renkerb0d045c2007-09-25 22:42:27 -070079 ackno = dcb->dccpd_ack_seq;
Herbert Xuedc9e812005-10-30 11:20:59 +110080 /* fall through */
81 default:
82 /*
Gerrit Renkeree1a1592007-09-26 11:30:02 -030083 * Set owner/destructor: some skbs are allocated via
84 * alloc_skb (e.g. when retransmission may happen).
85 * Only Data, DataAck, and Reset packets should come
86 * through here with skb->sk set.
Herbert Xuedc9e812005-10-30 11:20:59 +110087 */
88 WARN_ON(skb->sk);
89 skb_set_owner_w(skb, sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070090 break;
91 }
Arnaldo Carvalho de Melo24117722005-08-21 05:40:16 -030092
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -080093 if (dccp_insert_options(sk, skb)) {
94 kfree_skb(skb);
95 return -EPROTO;
96 }
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +090097
Herbert Xufda0fd62005-10-14 16:38:49 +100098
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070099 /* Build DCCP header and checksum it. */
Gerrit Renker9b420782006-11-10 11:22:32 -0200100 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700101 dh->dccph_type = dcb->dccpd_type;
102 dh->dccph_sport = inet->sport;
103 dh->dccph_dport = inet->dport;
104 dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
105 dh->dccph_ccval = dcb->dccpd_ccval;
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200106 dh->dccph_cscov = dp->dccps_pcslen;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700107 /* XXX For now we're using only 48 bits sequence numbers */
108 dh->dccph_x = 1;
109
Gerrit Renker73f18fd2008-07-26 11:59:10 +0100110 dccp_update_gss(sk, dcb->dccpd_seq);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700111 dccp_hdr_set_seq(dh, dp->dccps_gss);
112 if (set_ack)
113 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
114
115 switch (dcb->dccpd_type) {
116 case DCCP_PKT_REQUEST:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300117 dccp_hdr_request(skb)->dccph_req_service =
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700118 dp->dccps_service;
Gerrit Renker73f18fd2008-07-26 11:59:10 +0100119 /*
120 * Limit Ack window to ISS <= P.ackno <= GSS, so that
121 * only Responses to Requests we sent are considered.
122 */
123 dp->dccps_awl = dp->dccps_iss;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700124 break;
125 case DCCP_PKT_RESET:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300126 dccp_hdr_reset(skb)->dccph_reset_code =
127 dcb->dccpd_reset_code;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700128 break;
129 }
130
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200131 icsk->icsk_af_ops->send_check(sk, 0, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700132
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700133 if (set_ack)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700134 dccp_event_ack_sent(sk);
135
136 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
137
David S. Millere89862f2007-01-26 01:04:55 -0800138 err = icsk->icsk_af_ops->queue_xmit(skb, 0);
Gerrit Renkerb9df3cb2006-11-14 11:21:36 -0200139 return net_xmit_eval(err);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700140 }
141 return -ENOBUFS;
142}
143
Gerrit Renker61799832007-12-13 23:37:55 -0200144/**
145 * dccp_determine_ccmps - Find out about CCID-specfic packet-size limits
146 * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.),
147 * since the RX CCID is restricted to feedback packets (Acks), which are small
148 * in comparison with the data traffic. A value of 0 means "no current CCMPS".
149 */
150static u32 dccp_determine_ccmps(const struct dccp_sock *dp)
151{
152 const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid;
153
154 if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL)
155 return 0;
156 return tx_ccid->ccid_ops->ccid_ccmps;
157}
158
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700159unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
160{
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800161 struct inet_connection_sock *icsk = inet_csk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700162 struct dccp_sock *dp = dccp_sk(sk);
Gerrit Renker61799832007-12-13 23:37:55 -0200163 u32 ccmps = dccp_determine_ccmps(dp);
164 int cur_mps = ccmps ? min(pmtu, ccmps) : pmtu;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700165
Gerrit Renker61799832007-12-13 23:37:55 -0200166 /* Account for header lengths and IPv4/v6 option overhead */
167 cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len +
168 sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700169
170 /*
171 * FIXME: this should come from the CCID infrastructure, where, say,
172 * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
173 * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
174 * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
175 * make it a multiple of 4
176 */
177
Gerrit Renker61799832007-12-13 23:37:55 -0200178 cur_mps -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700179
180 /* And store cached results */
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800181 icsk->icsk_pmtu_cookie = pmtu;
Gerrit Renker61799832007-12-13 23:37:55 -0200182 dp->dccps_mss_cache = cur_mps;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700183
Gerrit Renker61799832007-12-13 23:37:55 -0200184 return cur_mps;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700185}
186
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800187EXPORT_SYMBOL_GPL(dccp_sync_mss);
188
Arnaldo Carvalho de Meloc530cfb2005-08-29 02:15:54 -0300189void dccp_write_space(struct sock *sk)
190{
191 read_lock(&sk->sk_callback_lock);
192
193 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
194 wake_up_interruptible(sk->sk_sleep);
195 /* Should agree with poll, otherwise some programs break */
196 if (sock_writeable(sk))
Pavel Emelyanov8d8ad9d2007-11-26 20:10:50 +0800197 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
Arnaldo Carvalho de Meloc530cfb2005-08-29 02:15:54 -0300198
199 read_unlock(&sk->sk_callback_lock);
200}
201
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300202/**
203 * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
Gerrit Renkerbc849872007-10-04 14:38:49 -0700204 * @sk: socket to wait for
205 * @skb: current skb to pass on for waiting
206 * @delay: sleep timeout in milliseconds (> 0)
207 * This function is called by default when the socket is closed, and
208 * when a non-zero linger time is set on the socket. For consistency
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300209 */
Gerrit Renkerbc849872007-10-04 14:38:49 -0700210static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300211{
212 struct dccp_sock *dp = dccp_sk(sk);
213 DEFINE_WAIT(wait);
Gerrit Renkerbc849872007-10-04 14:38:49 -0700214 unsigned long jiffdelay;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300215 int rc;
216
Gerrit Renkerbc849872007-10-04 14:38:49 -0700217 do {
218 dccp_pr_debug("delayed send by %d msec\n", delay);
219 jiffdelay = msecs_to_jiffies(delay);
220
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300221 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
222
Gerrit Renkerbc849872007-10-04 14:38:49 -0700223 sk->sk_write_pending++;
224 release_sock(sk);
225 schedule_timeout(jiffdelay);
226 lock_sock(sk);
227 sk->sk_write_pending--;
228
Ian McDonald97e58482006-08-26 19:16:45 -0700229 if (sk->sk_err)
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300230 goto do_error;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300231 if (signal_pending(current))
232 goto do_interrupted;
233
Gerrit Renker6b57c932006-11-28 19:55:06 -0200234 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
Gerrit Renkerbc849872007-10-04 14:38:49 -0700235 } while ((delay = rc) > 0);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300236out:
237 finish_wait(sk->sk_sleep, &wait);
238 return rc;
239
240do_error:
241 rc = -EPIPE;
242 goto out;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300243do_interrupted:
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200244 rc = -EINTR;
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300245 goto out;
246}
247
Ian McDonald97e58482006-08-26 19:16:45 -0700248void dccp_write_xmit(struct sock *sk, int block)
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700249{
Ian McDonald97e58482006-08-26 19:16:45 -0700250 struct dccp_sock *dp = dccp_sk(sk);
251 struct sk_buff *skb;
Ian McDonald97e58482006-08-26 19:16:45 -0700252
253 while ((skb = skb_peek(&sk->sk_write_queue))) {
Gerrit Renker6b57c932006-11-28 19:55:06 -0200254 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
Arnaldo Carvalho de Melod6809c12005-08-27 03:06:35 -0300255
Ian McDonald97e58482006-08-26 19:16:45 -0700256 if (err > 0) {
257 if (!block) {
258 sk_reset_timer(sk, &dp->dccps_xmit_timer,
259 msecs_to_jiffies(err)+jiffies);
260 break;
Ian McDonald5cc3741d2006-12-09 23:56:09 -0200261 } else
Gerrit Renkerbc849872007-10-04 14:38:49 -0700262 err = dccp_wait_for_ccid(sk, skb, err);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200263 if (err && err != -EINTR)
Gerrit Renker59348b12006-11-20 18:39:23 -0200264 DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
Ian McDonald97e58482006-08-26 19:16:45 -0700265 }
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);
Gerrit Renker59348b12006-11-20 18:39:23 -0200286 if (err)
287 DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
288 err);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200289 } else {
Gerrit Renker6626e362007-03-20 15:00:28 -0300290 dccp_pr_debug("packet discarded due to err=%d\n", err);
Patrick McHardyb08d5842007-02-27 09:57:37 -0800291 kfree_skb(skb);
Gerrit Renkerf6282f42006-12-10 00:05:12 -0200292 }
Ian McDonald97e58482006-08-26 19:16:45 -0700293 }
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700294}
295
Gerrit Renker59435442008-07-26 11:59:09 +0100296/**
297 * dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets
298 * There are only four retransmittable packet types in DCCP:
299 * - Request in client-REQUEST state (sec. 8.1.1),
300 * - CloseReq in server-CLOSEREQ state (sec. 8.3),
301 * - Close in node-CLOSING state (sec. 8.3),
302 * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()).
303 * This function expects sk->sk_send_head to contain the original skb.
304 */
305int dccp_retransmit_skb(struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700306{
Gerrit Renker59435442008-07-26 11:59:09 +0100307 WARN_ON(sk->sk_send_head == NULL);
308
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800309 if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700310 return -EHOSTUNREACH; /* Routing failure or similar. */
311
Gerrit Renker59435442008-07-26 11:59:09 +0100312 /* this count is used to distinguish original and retransmitted skb */
313 inet_csk(sk)->icsk_retransmits++;
314
315 return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700316}
317
318struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
319 struct request_sock *req)
320{
321 struct dccp_hdr *dh;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700322 struct dccp_request_sock *dreq;
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800323 const u32 dccp_header_size = sizeof(struct dccp_hdr) +
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700324 sizeof(struct dccp_hdr_ext) +
325 sizeof(struct dccp_hdr_response);
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800326 struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700327 GFP_ATOMIC);
328 if (skb == NULL)
329 return NULL;
330
331 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800332 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700333
334 skb->dst = dst_clone(dst);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700335
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700336 dreq = dccp_rsk(req);
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200337 if (inet_rsk(req)->acked) /* increase ISS upon retransmission */
338 dccp_inc_seqno(&dreq->dreq_iss);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700339 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700340 DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800341
Gerrit Renkeraf3b8672007-12-13 12:38:11 -0200342 if (dccp_insert_options_rsk(dreq, skb)) {
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800343 kfree_skb(skb);
344 return NULL;
345 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700346
Gerrit Renker09dbc382006-11-14 12:57:34 -0200347 /* Build and checksum header */
Gerrit Renker9b420782006-11-10 11:22:32 -0200348 dh = dccp_zeroed_hdr(skb, dccp_header_size);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700349
Gerrit Renker944f7502008-10-19 23:36:47 -0700350 dh->dccph_sport = inet_rsk(req)->loc_port;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700351 dh->dccph_dport = inet_rsk(req)->rmt_port;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300352 dh->dccph_doff = (dccp_header_size +
353 DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700354 dh->dccph_type = DCCP_PKT_RESPONSE;
355 dh->dccph_x = 1;
Arnaldo Carvalho de Melo67e6b622005-09-16 16:58:40 -0700356 dccp_hdr_set_seq(dh, dreq->dreq_iss);
357 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
358 dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700359
Gerrit Renker6f4e5ff2006-11-10 17:43:06 -0200360 dccp_csum_outgoing(skb);
361
Gerrit Renkere11d9d32006-11-13 13:12:07 -0200362 /* We use `acked' to remember that a Response was already sent. */
363 inet_rsk(req)->acked = 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700364 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
365 return skb;
366}
367
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800368EXPORT_SYMBOL_GPL(dccp_make_response);
369
Gerrit Renkere356d372007-09-26 14:35:19 -0300370/* answer offending packet in @rcv_skb with Reset from control socket @ctl */
Denis V. Lunev7630f022008-04-03 14:20:52 -0700371struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb)
Gerrit Renkere356d372007-09-26 14:35:19 -0300372{
373 struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh;
374 struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb);
375 const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
376 sizeof(struct dccp_hdr_ext) +
377 sizeof(struct dccp_hdr_reset);
378 struct dccp_hdr_reset *dhr;
379 struct sk_buff *skb;
380
Denis V. Lunev7630f022008-04-03 14:20:52 -0700381 skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
Gerrit Renkere356d372007-09-26 14:35:19 -0300382 if (skb == NULL)
383 return NULL;
384
Denis V. Lunev7630f022008-04-03 14:20:52 -0700385 skb_reserve(skb, sk->sk_prot->max_header);
Gerrit Renkere356d372007-09-26 14:35:19 -0300386
387 /* Swap the send and the receive. */
388 dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
389 dh->dccph_type = DCCP_PKT_RESET;
390 dh->dccph_sport = rxdh->dccph_dport;
391 dh->dccph_dport = rxdh->dccph_sport;
392 dh->dccph_doff = dccp_hdr_reset_len / 4;
393 dh->dccph_x = 1;
394
395 dhr = dccp_hdr_reset(skb);
396 dhr->dccph_reset_code = dcb->dccpd_reset_code;
397
398 switch (dcb->dccpd_reset_code) {
399 case DCCP_RESET_CODE_PACKET_ERROR:
400 dhr->dccph_reset_data[0] = rxdh->dccph_type;
401 break;
402 case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */
403 case DCCP_RESET_CODE_MANDATORY_ERROR:
404 memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);
405 break;
406 }
407 /*
408 * From RFC 4340, 8.3.1:
409 * If P.ackno exists, set R.seqno := P.ackno + 1.
410 * Else set R.seqno := 0.
411 */
412 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
413 dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));
414 dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);
415
416 dccp_csum_outgoing(skb);
417 return skb;
418}
419
420EXPORT_SYMBOL_GPL(dccp_ctl_make_reset);
421
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300422/* send Reset on established socket, to close or abort the connection */
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800423int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
424{
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300425 struct sk_buff *skb;
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800426 /*
427 * FIXME: what if rebuild_header fails?
428 * Should we be doing a rebuild_header here?
429 */
Gerrit Renkerf53dc672007-11-28 08:35:08 +0000430 int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk);
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800431
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300432 if (err != 0)
433 return err;
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800434
Gerrit Renkeree1a1592007-09-26 11:30:02 -0300435 skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC);
436 if (skb == NULL)
437 return -ENOBUFS;
438
439 /* Reserve space for headers and prepare control bits. */
440 skb_reserve(skb, sk->sk_prot->max_header);
441 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
442 DCCP_SKB_CB(skb)->dccpd_reset_code = code;
443
444 return dccp_transmit_skb(sk, skb);
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -0800445}
446
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700447/*
448 * Do all connect socket setups that can be done AF independent.
449 */
450static inline void dccp_connect_init(struct sock *sk)
451{
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800452 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700453 struct dst_entry *dst = __sk_dst_get(sk);
454 struct inet_connection_sock *icsk = inet_csk(sk);
455
456 sk->sk_err = 0;
457 sock_reset_flag(sk, SOCK_DONE);
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900458
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700459 dccp_sync_mss(sk, dst_mtu(dst));
460
Gerrit Renker73f18fd2008-07-26 11:59:10 +0100461 /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */
Gerrit Renkerd7f73652006-11-13 13:34:38 -0200462 dp->dccps_gar = dp->dccps_iss;
463
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700464 icsk->icsk_retransmits = 0;
465}
466
467int dccp_connect(struct sock *sk)
468{
469 struct sk_buff *skb;
470 struct inet_connection_sock *icsk = inet_csk(sk);
471
472 dccp_connect_init(sk);
473
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800474 skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700475 if (unlikely(skb == NULL))
476 return -ENOBUFS;
477
478 /* Reserve space for headers. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800479 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700480
481 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700482
Herbert Xu48918a42005-10-30 11:20:59 +1100483 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700484 dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
485 DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
486
487 /* Timer for repeating the REQUEST until an answer. */
Arnaldo Carvalho de Melo27258ee2005-08-09 20:30:56 -0700488 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
489 icsk->icsk_rto, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700490 return 0;
491}
492
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800493EXPORT_SYMBOL_GPL(dccp_connect);
494
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700495void dccp_send_ack(struct sock *sk)
496{
497 /* If we have been reset, we may not send again. */
498 if (sk->sk_state != DCCP_CLOSED) {
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800499 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
500 GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700501
502 if (skb == NULL) {
503 inet_csk_schedule_ack(sk);
504 inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300505 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
506 TCP_DELACK_MAX,
507 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700508 return;
509 }
510
511 /* Reserve space for headers */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800512 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700513 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700514 dccp_transmit_skb(sk, skb);
515 }
516}
517
518EXPORT_SYMBOL_GPL(dccp_send_ack);
519
Gerrit Renker1e2f0e52008-06-11 11:19:09 +0100520#if 0
Gerrit Renker727ecc52007-09-26 11:26:04 -0300521/* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700522void dccp_send_delayed_ack(struct sock *sk)
523{
524 struct inet_connection_sock *icsk = inet_csk(sk);
525 /*
526 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
527 * with using 2s, and active senders also piggyback the ACK into a
528 * DATAACK packet, so this is really for quiescent senders.
529 */
530 unsigned long timeout = jiffies + 2 * HZ;
531
532 /* Use new timeout only if there wasn't a older one earlier. */
533 if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
534 /* If delack timer was blocked or is about to expire,
535 * send ACK now.
536 *
537 * FIXME: check the "about to expire" part
538 */
539 if (icsk->icsk_ack.blocked) {
540 dccp_send_ack(sk);
541 return;
542 }
543
544 if (!time_before(timeout, icsk->icsk_ack.timeout))
545 timeout = icsk->icsk_ack.timeout;
546 }
547 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
548 icsk->icsk_ack.timeout = timeout;
549 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
550}
Gerrit Renker1e2f0e52008-06-11 11:19:09 +0100551#endif
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700552
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700553void dccp_send_sync(struct sock *sk, const u64 ackno,
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300554 const enum dccp_pkt_type pkt_type)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700555{
556 /*
557 * We are not putting this on the write queue, so
558 * dccp_transmit_skb() will set the ownership to this
559 * sock.
560 */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800561 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700562
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700563 if (skb == NULL) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700564 /* FIXME: how to make sure the sync is sent? */
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700565 DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700566 return;
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700567 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700568
569 /* Reserve space for headers and prepare control bits. */
Arnaldo Carvalho de Melo118b2c92006-03-20 22:31:09 -0800570 skb_reserve(skb, sk->sk_prot->max_header);
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300571 DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
Gerrit Renkerb0d045c2007-09-25 22:42:27 -0700572 DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700573
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700574 dccp_transmit_skb(sk, skb);
575}
576
Arnaldo Carvalho de Melob61fafc2006-03-20 21:25:11 -0800577EXPORT_SYMBOL_GPL(dccp_send_sync);
578
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300579/*
580 * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
581 * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
582 * any circumstances.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700583 */
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700584void dccp_send_close(struct sock *sk, const int active)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700585{
586 struct dccp_sock *dp = dccp_sk(sk);
587 struct sk_buff *skb;
Al Viro7d877f32005-10-21 03:20:43 -0400588 const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700589
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700590 skb = alloc_skb(sk->sk_prot->max_header, prio);
591 if (skb == NULL)
592 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700593
594 /* Reserve space for headers and prepare control bits. */
595 skb_reserve(skb, sk->sk_prot->max_header);
Gerrit Renkerb8599d22007-12-13 12:25:01 -0200596 if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait)
597 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ;
598 else
599 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700600
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700601 if (active) {
Ian McDonald97e58482006-08-26 19:16:45 -0700602 dccp_write_xmit(sk, 1);
Herbert Xu48918a42005-10-30 11:20:59 +1100603 dccp_skb_entail(sk, skb);
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700604 dccp_transmit_skb(sk, skb_clone(skb, prio));
Gerrit Renker92d31922007-12-13 12:02:43 -0200605 /*
606 * Retransmission timer for active-close: RFC 4340, 8.3 requires
607 * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ
608 * state can be left. The initial timeout is 2 RTTs.
609 * Since RTT measurement is done by the CCIDs, there is no easy
610 * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4
611 * is too low (200ms); we use a high value to avoid unnecessary
612 * retransmissions when the link RTT is > 0.2 seconds.
613 * FIXME: Let main module sample RTTs and use that instead.
614 */
615 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
616 DCCP_TIMEOUT_INIT, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700617 } else
618 dccp_transmit_skb(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700619}