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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);
Eric Dumazetaa62d762016-04-27 16:44:28 -070031 __DCCP_INC_STATS(DCCP_MIB_ABORTONTIMEOUT);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070032}
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)
Eric Dumazetaa62d762016-04-27 16:44:28 -0700103 __DCCP_INC_STATS(DCCP_MIB_TIMEOUTS);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700104
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
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700164static void dccp_keepalive_timer(unsigned long data)
165{
166 struct sock *sk = (struct sock *)data;
167
Eric Dumazetfa76ce732015-03-19 19:04:20 -0700168 pr_err("dccp should not use a keepalive timer !\n");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700169 sock_put(sk);
170}
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200171
172/* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */
173static void dccp_delack_timer(unsigned long data)
174{
175 struct sock *sk = (struct sock *)data;
176 struct inet_connection_sock *icsk = inet_csk(sk);
177
178 bh_lock_sock(sk);
179 if (sock_owned_by_user(sk)) {
180 /* Try again later. */
181 icsk->icsk_ack.blocked = 1;
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700182 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200183 sk_reset_timer(sk, &icsk->icsk_delack_timer,
184 jiffies + TCP_DELACK_MIN);
185 goto out;
186 }
187
188 if (sk->sk_state == DCCP_CLOSED ||
189 !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
190 goto out;
191 if (time_after(icsk->icsk_ack.timeout, jiffies)) {
192 sk_reset_timer(sk, &icsk->icsk_delack_timer,
193 icsk->icsk_ack.timeout);
194 goto out;
195 }
196
197 icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
198
199 if (inet_csk_ack_scheduled(sk)) {
200 if (!icsk->icsk_ack.pingpong) {
201 /* Delayed ACK missed: inflate ATO. */
202 icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
203 icsk->icsk_rto);
204 } else {
205 /* Delayed ACK missed: leave pingpong mode and
206 * deflate ATO.
207 */
208 icsk->icsk_ack.pingpong = 0;
209 icsk->icsk_ack.ato = TCP_ATO_MIN;
210 }
211 dccp_send_ack(sk);
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700212 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKS);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200213 }
214out:
215 bh_unlock_sock(sk);
216 sock_put(sk);
217}
218
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000219/**
220 * dccp_write_xmitlet - Workhorse for CCID packet dequeueing interface
221 * See the comments above %ccid_dequeueing_decision for supported modes.
222 */
223static void dccp_write_xmitlet(unsigned long data)
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800224{
225 struct sock *sk = (struct sock *)data;
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800226
227 bh_lock_sock(sk);
228 if (sock_owned_by_user(sk))
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000229 sk_reset_timer(sk, &dccp_sk(sk)->dccps_xmit_timer, jiffies + 1);
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800230 else
Gerrit Renkerb1fcf552010-10-27 19:16:27 +0000231 dccp_write_xmit(sk);
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800232 bh_unlock_sock(sk);
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800233}
234
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000235static void dccp_write_xmit_timer(unsigned long data)
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800236{
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000237 dccp_write_xmitlet(data);
238 sock_put((struct sock *)data);
Gerrit Renkeraabb6012007-03-09 13:47:58 -0800239}
240
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200241void dccp_init_xmit_timers(struct sock *sk)
242{
Gerrit Renkerdc841e32010-10-27 19:16:26 +0000243 struct dccp_sock *dp = dccp_sk(sk);
244
245 tasklet_init(&dp->dccps_xmitlet, dccp_write_xmitlet, (unsigned long)sk);
246 setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer,
247 (unsigned long)sk);
Gerrit Renker4ed800d2006-11-13 13:26:51 -0200248 inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer,
249 &dccp_keepalive_timer);
250}
Gerrit Renker4c70f382007-09-25 22:40:13 -0700251
252static ktime_t dccp_timestamp_seed;
253/**
254 * dccp_timestamp - 10s of microseconds time source
255 * Returns the number of 10s of microseconds since loading DCCP. This is native
256 * DCCP time difference format (RFC 4340, sec. 13).
257 * Please note: This will wrap around about circa every 11.9 hours.
258 */
259u32 dccp_timestamp(void)
260{
Chen Gang5c4a43b2014-05-21 08:19:34 +0800261 u64 delta = (u64)ktime_us_delta(ktime_get_real(), dccp_timestamp_seed);
Gerrit Renker4c70f382007-09-25 22:40:13 -0700262
263 do_div(delta, 10);
264 return delta;
265}
266EXPORT_SYMBOL_GPL(dccp_timestamp);
267
268void __init dccp_timestamping_init(void)
269{
270 dccp_timestamp_seed = ktime_get_real();
271}