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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>
Paul Gortmakerbc3b2d72011-07-15 11:47:34 -040015#include <linux/export.h>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070016
17#include "dccp.h"
18
Gerrit Renker2e2e9e92006-11-13 13:23:52 -020019/* sysctl variables governing numbers of retransmission attempts */
20int sysctl_dccp_request_retries __read_mostly = TCP_SYN_RETRIES;
21int sysctl_dccp_retries1 __read_mostly = TCP_RETR1;
22int sysctl_dccp_retries2 __read_mostly = TCP_RETR2;
23
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070024static void dccp_write_err(struct sock *sk)
25{
26 sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
27 sk->sk_error_report(sk);
28
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -080029 dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070030 dccp_done(sk);
31 DCCP_INC_STATS_BH(DCCP_MIB_ABORTONTIMEOUT);
32}
33
34/* A write timeout has occurred. Process the after effects. */
35static int dccp_write_timeout(struct sock *sk)
36{
37 const struct inet_connection_sock *icsk = inet_csk(sk);
38 int retry_until;
39
40 if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) {
41 if (icsk->icsk_retransmits != 0)
Eric Dumazetb6c67122010-04-08 23:03:29 +000042 dst_negative_advice(sk);
Gerrit Renker2e2e9e92006-11-13 13:23:52 -020043 retry_until = icsk->icsk_syn_retries ?
44 : sysctl_dccp_request_retries;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070045 } else {
Gerrit Renker2e2e9e92006-11-13 13:23:52 -020046 if (icsk->icsk_retransmits >= sysctl_dccp_retries1) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -030047 /* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu
48 black hole detection. :-(
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070049
50 It is place to make it. It is not made. I do not want
51 to make it. It is disguisting. It does not work in any
52 case. Let me to cite the same draft, which requires for
53 us to implement this:
54
55 "The one security concern raised by this memo is that ICMP black holes
56 are often caused by over-zealous security administrators who block
57 all ICMP messages. It is vitally important that those who design and
58 deploy security systems understand the impact of strict filtering on
59 upper-layer protocols. The safest web site in the world is worthless
60 if most TCP implementations cannot transfer data from it. It would
61 be far nicer to have all of the black holes fixed rather than fixing
62 all of the TCP implementations."
63
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +090064 Golden words :-).
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070065 */
66
Eric Dumazetb6c67122010-04-08 23:03:29 +000067 dst_negative_advice(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070068 }
69
Gerrit Renker2e2e9e92006-11-13 13:23:52 -020070 retry_until = sysctl_dccp_retries2;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070071 /*
72 * FIXME: see tcp_write_timout and tcp_out_of_resources
73 */
74 }
75
76 if (icsk->icsk_retransmits >= retry_until) {
77 /* Has it gone just too far? */
78 dccp_write_err(sk);
79 return 1;
80 }
81 return 0;
82}
83
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070084/*
85 * The DCCP retransmit timer.
86 */
87static void dccp_retransmit_timer(struct sock *sk)
88{
89 struct inet_connection_sock *icsk = inet_csk(sk);
90
91 /*
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070092 * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was
93 * sent, no need to retransmit, this sock is dead.
94 */
95 if (dccp_write_timeout(sk))
Gerrit Renker59435442008-07-26 11:59:09 +010096 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070097
98 /*
99 * We want to know the number of packets retransmitted, not the
100 * total number of retransmissions of clones of original packets.
101 */
102 if (icsk->icsk_retransmits == 0)
103 DCCP_INC_STATS_BH(DCCP_MIB_TIMEOUTS);
104
Gerrit Renker59435442008-07-26 11:59:09 +0100105 if (dccp_retransmit_skb(sk) != 0) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700106 /*
107 * Retransmission failed because of local congestion,
108 * do not backoff.
109 */
Gerrit Renker59435442008-07-26 11:59:09 +0100110 if (--icsk->icsk_retransmits == 0)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700111 icsk->icsk_retransmits = 1;
112 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
113 min(icsk->icsk_rto,
114 TCP_RESOURCE_PROBE_INTERVAL),
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300115 DCCP_RTO_MAX);
Gerrit Renker59435442008-07-26 11:59:09 +0100116 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700117 }
118
119 icsk->icsk_backoff++;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700120
121 icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300122 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto,
123 DCCP_RTO_MAX);
Gerrit Renker2e2e9e92006-11-13 13:23:52 -0200124 if (icsk->icsk_retransmits > sysctl_dccp_retries1)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700125 __sk_dst_reset(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700126}
127
128static void dccp_write_timer(unsigned long data)
129{
130 struct sock *sk = (struct sock *)data;
131 struct inet_connection_sock *icsk = inet_csk(sk);
132 int event = 0;
133
134 bh_lock_sock(sk);
135 if (sock_owned_by_user(sk)) {
136 /* Try again later */
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300137 sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
138 jiffies + (HZ / 20));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700139 goto out;
140 }
141
142 if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending)
143 goto out;
144
145 if (time_after(icsk->icsk_timeout, jiffies)) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300146 sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
147 icsk->icsk_timeout);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700148 goto out;
149 }
150
151 event = icsk->icsk_pending;
152 icsk->icsk_pending = 0;
153
154 switch (event) {
155 case ICSK_TIME_RETRANS:
156 dccp_retransmit_timer(sk);
157 break;
158 }
159out:
160 bh_unlock_sock(sk);
161 sock_put(sk);
162}
163
164/*
165 * Timer for listening sockets
166 */
167static void dccp_response_timer(struct sock *sk)
168{
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300169 inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, DCCP_TIMEOUT_INIT,
170 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700171}
172
173static void dccp_keepalive_timer(unsigned long data)
174{
175 struct sock *sk = (struct sock *)data;
176
177 /* Only process if socket is not in use. */
178 bh_lock_sock(sk);
179 if (sock_owned_by_user(sk)) {
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200180 /* Try again later. */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700181 inet_csk_reset_keepalive_timer(sk, HZ / 20);
182 goto out;
183 }
184
185 if (sk->sk_state == DCCP_LISTEN) {
186 dccp_response_timer(sk);
187 goto out;
188 }
189out:
190 bh_unlock_sock(sk);
191 sock_put(sk);
192}
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200193
194/* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */
195static void dccp_delack_timer(unsigned long data)
196{
197 struct sock *sk = (struct sock *)data;
198 struct inet_connection_sock *icsk = inet_csk(sk);
199
200 bh_lock_sock(sk);
201 if (sock_owned_by_user(sk)) {
202 /* Try again later. */
203 icsk->icsk_ack.blocked = 1;
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700204 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200205 sk_reset_timer(sk, &icsk->icsk_delack_timer,
206 jiffies + TCP_DELACK_MIN);
207 goto out;
208 }
209
210 if (sk->sk_state == DCCP_CLOSED ||
211 !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
212 goto out;
213 if (time_after(icsk->icsk_ack.timeout, jiffies)) {
214 sk_reset_timer(sk, &icsk->icsk_delack_timer,
215 icsk->icsk_ack.timeout);
216 goto out;
217 }
218
219 icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
220
221 if (inet_csk_ack_scheduled(sk)) {
222 if (!icsk->icsk_ack.pingpong) {
223 /* Delayed ACK missed: inflate ATO. */
224 icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
225 icsk->icsk_rto);
226 } else {
227 /* Delayed ACK missed: leave pingpong mode and
228 * deflate ATO.
229 */
230 icsk->icsk_ack.pingpong = 0;
231 icsk->icsk_ack.ato = TCP_ATO_MIN;
232 }
233 dccp_send_ack(sk);
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700234 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKS);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200235 }
236out:
237 bh_unlock_sock(sk);
238 sock_put(sk);
239}
240
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000241/**
242 * dccp_write_xmitlet - Workhorse for CCID packet dequeueing interface
243 * See the comments above %ccid_dequeueing_decision for supported modes.
244 */
245static void dccp_write_xmitlet(unsigned long data)
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800246{
247 struct sock *sk = (struct sock *)data;
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800248
249 bh_lock_sock(sk);
250 if (sock_owned_by_user(sk))
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000251 sk_reset_timer(sk, &dccp_sk(sk)->dccps_xmit_timer, jiffies + 1);
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800252 else
Gerrit Renkerb1fcf552010-10-27 19:16:27 +0000253 dccp_write_xmit(sk);
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800254 bh_unlock_sock(sk);
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800255}
256
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000257static void dccp_write_xmit_timer(unsigned long data)
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800258{
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000259 dccp_write_xmitlet(data);
260 sock_put((struct sock *)data);
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 Renkerdc841e32010-10-27 19:16:26 +0000265 struct dccp_sock *dp = dccp_sk(sk);
266
267 tasklet_init(&dp->dccps_xmitlet, dccp_write_xmitlet, (unsigned long)sk);
268 setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer,
269 (unsigned long)sk);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200270 inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer,
271 &dccp_keepalive_timer);
272}
Gerrit Renker4c70f382007-09-25 22:40:13 -0700273
274static ktime_t dccp_timestamp_seed;
275/**
276 * dccp_timestamp - 10s of microseconds time source
277 * Returns the number of 10s of microseconds since loading DCCP. This is native
278 * DCCP time difference format (RFC 4340, sec. 13).
279 * Please note: This will wrap around about circa every 11.9 hours.
280 */
281u32 dccp_timestamp(void)
282{
Chen Gang5c4a43b2014-05-21 08:19:34 +0800283 u64 delta = (u64)ktime_us_delta(ktime_get_real(), dccp_timestamp_seed);
Gerrit Renker4c70f382007-09-25 22:40:13 -0700284
285 do_div(delta, 10);
286 return delta;
287}
288EXPORT_SYMBOL_GPL(dccp_timestamp);
289
290void __init dccp_timestamping_init(void)
291{
292 dccp_timestamp_seed = ktime_get_real();
293}