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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
2 * net/dccp/timer.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>
14#include <linux/skbuff.h>
15
16#include "dccp.h"
17
Gerrit Renker2e2e9e92006-11-13 13:23:52 -020018/* sysctl variables governing numbers of retransmission attempts */
19int sysctl_dccp_request_retries __read_mostly = TCP_SYN_RETRIES;
20int sysctl_dccp_retries1 __read_mostly = TCP_RETR1;
21int sysctl_dccp_retries2 __read_mostly = TCP_RETR2;
22
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070023static void dccp_write_err(struct sock *sk)
24{
25 sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
26 sk->sk_error_report(sk);
27
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -080028 dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070029 dccp_done(sk);
30 DCCP_INC_STATS_BH(DCCP_MIB_ABORTONTIMEOUT);
31}
32
33/* A write timeout has occurred. Process the after effects. */
34static int dccp_write_timeout(struct sock *sk)
35{
36 const struct inet_connection_sock *icsk = inet_csk(sk);
37 int retry_until;
38
39 if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) {
40 if (icsk->icsk_retransmits != 0)
Krishna Kumarea94ff32009-10-19 23:46:45 +000041 dst_negative_advice(&sk->sk_dst_cache, sk);
Gerrit Renker2e2e9e92006-11-13 13:23:52 -020042 retry_until = icsk->icsk_syn_retries ?
43 : sysctl_dccp_request_retries;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070044 } else {
Gerrit Renker2e2e9e92006-11-13 13:23:52 -020045 if (icsk->icsk_retransmits >= sysctl_dccp_retries1) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -030046 /* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu
47 black hole detection. :-(
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070048
49 It is place to make it. It is not made. I do not want
50 to make it. It is disguisting. It does not work in any
51 case. Let me to cite the same draft, which requires for
52 us to implement this:
53
54 "The one security concern raised by this memo is that ICMP black holes
55 are often caused by over-zealous security administrators who block
56 all ICMP messages. It is vitally important that those who design and
57 deploy security systems understand the impact of strict filtering on
58 upper-layer protocols. The safest web site in the world is worthless
59 if most TCP implementations cannot transfer data from it. It would
60 be far nicer to have all of the black holes fixed rather than fixing
61 all of the TCP implementations."
62
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +090063 Golden words :-).
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070064 */
65
Krishna Kumarea94ff32009-10-19 23:46:45 +000066 dst_negative_advice(&sk->sk_dst_cache, sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070067 }
68
Gerrit Renker2e2e9e92006-11-13 13:23:52 -020069 retry_until = sysctl_dccp_retries2;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070070 /*
71 * FIXME: see tcp_write_timout and tcp_out_of_resources
72 */
73 }
74
75 if (icsk->icsk_retransmits >= retry_until) {
76 /* Has it gone just too far? */
77 dccp_write_err(sk);
78 return 1;
79 }
80 return 0;
81}
82
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070083/*
84 * The DCCP retransmit timer.
85 */
86static void dccp_retransmit_timer(struct sock *sk)
87{
88 struct inet_connection_sock *icsk = inet_csk(sk);
89
90 /*
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070091 * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was
92 * sent, no need to retransmit, this sock is dead.
93 */
94 if (dccp_write_timeout(sk))
Gerrit Renker59435442008-07-26 11:59:09 +010095 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070096
97 /*
98 * We want to know the number of packets retransmitted, not the
99 * total number of retransmissions of clones of original packets.
100 */
101 if (icsk->icsk_retransmits == 0)
102 DCCP_INC_STATS_BH(DCCP_MIB_TIMEOUTS);
103
Gerrit Renker59435442008-07-26 11:59:09 +0100104 if (dccp_retransmit_skb(sk) != 0) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700105 /*
106 * Retransmission failed because of local congestion,
107 * do not backoff.
108 */
Gerrit Renker59435442008-07-26 11:59:09 +0100109 if (--icsk->icsk_retransmits == 0)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700110 icsk->icsk_retransmits = 1;
111 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
112 min(icsk->icsk_rto,
113 TCP_RESOURCE_PROBE_INTERVAL),
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300114 DCCP_RTO_MAX);
Gerrit Renker59435442008-07-26 11:59:09 +0100115 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700116 }
117
118 icsk->icsk_backoff++;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700119
120 icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300121 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto,
122 DCCP_RTO_MAX);
Gerrit Renker2e2e9e92006-11-13 13:23:52 -0200123 if (icsk->icsk_retransmits > sysctl_dccp_retries1)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700124 __sk_dst_reset(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700125}
126
127static void dccp_write_timer(unsigned long data)
128{
129 struct sock *sk = (struct sock *)data;
130 struct inet_connection_sock *icsk = inet_csk(sk);
131 int event = 0;
132
133 bh_lock_sock(sk);
134 if (sock_owned_by_user(sk)) {
135 /* Try again later */
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300136 sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
137 jiffies + (HZ / 20));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700138 goto out;
139 }
140
141 if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending)
142 goto out;
143
144 if (time_after(icsk->icsk_timeout, jiffies)) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300145 sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
146 icsk->icsk_timeout);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700147 goto out;
148 }
149
150 event = icsk->icsk_pending;
151 icsk->icsk_pending = 0;
152
153 switch (event) {
154 case ICSK_TIME_RETRANS:
155 dccp_retransmit_timer(sk);
156 break;
157 }
158out:
159 bh_unlock_sock(sk);
160 sock_put(sk);
161}
162
163/*
164 * Timer for listening sockets
165 */
166static void dccp_response_timer(struct sock *sk)
167{
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300168 inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, DCCP_TIMEOUT_INIT,
169 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700170}
171
172static void dccp_keepalive_timer(unsigned long data)
173{
174 struct sock *sk = (struct sock *)data;
175
176 /* Only process if socket is not in use. */
177 bh_lock_sock(sk);
178 if (sock_owned_by_user(sk)) {
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200179 /* Try again later. */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700180 inet_csk_reset_keepalive_timer(sk, HZ / 20);
181 goto out;
182 }
183
184 if (sk->sk_state == DCCP_LISTEN) {
185 dccp_response_timer(sk);
186 goto out;
187 }
188out:
189 bh_unlock_sock(sk);
190 sock_put(sk);
191}
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200192
193/* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */
194static void dccp_delack_timer(unsigned long data)
195{
196 struct sock *sk = (struct sock *)data;
197 struct inet_connection_sock *icsk = inet_csk(sk);
198
199 bh_lock_sock(sk);
200 if (sock_owned_by_user(sk)) {
201 /* Try again later. */
202 icsk->icsk_ack.blocked = 1;
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700203 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200204 sk_reset_timer(sk, &icsk->icsk_delack_timer,
205 jiffies + TCP_DELACK_MIN);
206 goto out;
207 }
208
209 if (sk->sk_state == DCCP_CLOSED ||
210 !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
211 goto out;
212 if (time_after(icsk->icsk_ack.timeout, jiffies)) {
213 sk_reset_timer(sk, &icsk->icsk_delack_timer,
214 icsk->icsk_ack.timeout);
215 goto out;
216 }
217
218 icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
219
220 if (inet_csk_ack_scheduled(sk)) {
221 if (!icsk->icsk_ack.pingpong) {
222 /* Delayed ACK missed: inflate ATO. */
223 icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
224 icsk->icsk_rto);
225 } else {
226 /* Delayed ACK missed: leave pingpong mode and
227 * deflate ATO.
228 */
229 icsk->icsk_ack.pingpong = 0;
230 icsk->icsk_ack.ato = TCP_ATO_MIN;
231 }
232 dccp_send_ack(sk);
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700233 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKS);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200234 }
235out:
236 bh_unlock_sock(sk);
237 sock_put(sk);
238}
239
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800240/* Transmit-delay timer: used by the CCIDs to delay actual send time */
Adrian Bunkc93a8822007-03-24 21:01:31 -0700241static void dccp_write_xmit_timer(unsigned long data)
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800242{
243 struct sock *sk = (struct sock *)data;
244 struct dccp_sock *dp = dccp_sk(sk);
245
246 bh_lock_sock(sk);
247 if (sock_owned_by_user(sk))
248 sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);
249 else
250 dccp_write_xmit(sk, 0);
251 bh_unlock_sock(sk);
252 sock_put(sk);
253}
254
255static void dccp_init_write_xmit_timer(struct sock *sk)
256{
257 struct dccp_sock *dp = dccp_sk(sk);
258
Pavel Emelyanovb24b8a22008-01-23 21:20:07 -0800259 setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer,
260 (unsigned long)sk);
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800261}
262
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200263void dccp_init_xmit_timers(struct sock *sk)
264{
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800265 dccp_init_write_xmit_timer(sk);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200266 inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer,
267 &dccp_keepalive_timer);
268}
Gerrit Renker4c70f382007-09-25 22:40:13 -0700269
270static ktime_t dccp_timestamp_seed;
271/**
272 * dccp_timestamp - 10s of microseconds time source
273 * Returns the number of 10s of microseconds since loading DCCP. This is native
274 * DCCP time difference format (RFC 4340, sec. 13).
275 * Please note: This will wrap around about circa every 11.9 hours.
276 */
277u32 dccp_timestamp(void)
278{
279 s64 delta = ktime_us_delta(ktime_get_real(), dccp_timestamp_seed);
280
281 do_div(delta, 10);
282 return delta;
283}
284EXPORT_SYMBOL_GPL(dccp_timestamp);
285
286void __init dccp_timestamping_init(void)
287{
288 dccp_timestamp_seed = ktime_get_real();
289}