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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
2 * net/dccp/timer.c
3 *
4 * 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
13#include <linux/config.h>
14#include <linux/dccp.h>
15#include <linux/skbuff.h>
16
17#include "dccp.h"
18
19static void dccp_write_timer(unsigned long data);
20static void dccp_keepalive_timer(unsigned long data);
21static void dccp_delack_timer(unsigned long data);
22
23void dccp_init_xmit_timers(struct sock *sk)
24{
25 inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer,
26 &dccp_keepalive_timer);
27}
28
29static void dccp_write_err(struct sock *sk)
30{
31 sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
32 sk->sk_error_report(sk);
33
Arnaldo Carvalho de Melo017487d2006-03-20 19:25:24 -080034 dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070035 dccp_done(sk);
36 DCCP_INC_STATS_BH(DCCP_MIB_ABORTONTIMEOUT);
37}
38
39/* A write timeout has occurred. Process the after effects. */
40static int dccp_write_timeout(struct sock *sk)
41{
42 const struct inet_connection_sock *icsk = inet_csk(sk);
43 int retry_until;
44
45 if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) {
46 if (icsk->icsk_retransmits != 0)
47 dst_negative_advice(&sk->sk_dst_cache);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -030048 retry_until = icsk->icsk_syn_retries ? :
49 /* FIXME! */ 3 /* FIXME! sysctl_tcp_syn_retries */;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070050 } else {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -030051 if (icsk->icsk_retransmits >=
52 /* FIXME! sysctl_tcp_retries1 */ 5 /* FIXME! */) {
53 /* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu
54 black hole detection. :-(
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070055
56 It is place to make it. It is not made. I do not want
57 to make it. It is disguisting. It does not work in any
58 case. Let me to cite the same draft, which requires for
59 us to implement this:
60
61 "The one security concern raised by this memo is that ICMP black holes
62 are often caused by over-zealous security administrators who block
63 all ICMP messages. It is vitally important that those who design and
64 deploy security systems understand the impact of strict filtering on
65 upper-layer protocols. The safest web site in the world is worthless
66 if most TCP implementations cannot transfer data from it. It would
67 be far nicer to have all of the black holes fixed rather than fixing
68 all of the TCP implementations."
69
70 Golden words :-).
71 */
72
73 dst_negative_advice(&sk->sk_dst_cache);
74 }
75
76 retry_until = /* FIXME! */ 15 /* FIXME! sysctl_tcp_retries2 */;
77 /*
78 * FIXME: see tcp_write_timout and tcp_out_of_resources
79 */
80 }
81
82 if (icsk->icsk_retransmits >= retry_until) {
83 /* Has it gone just too far? */
84 dccp_write_err(sk);
85 return 1;
86 }
87 return 0;
88}
89
90/* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */
91static void dccp_delack_timer(unsigned long data)
92{
93 struct sock *sk = (struct sock *)data;
94 struct inet_connection_sock *icsk = inet_csk(sk);
95
96 bh_lock_sock(sk);
97 if (sock_owned_by_user(sk)) {
98 /* Try again later. */
99 icsk->icsk_ack.blocked = 1;
100 NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300101 sk_reset_timer(sk, &icsk->icsk_delack_timer,
102 jiffies + TCP_DELACK_MIN);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700103 goto out;
104 }
105
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300106 if (sk->sk_state == DCCP_CLOSED ||
107 !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700108 goto out;
109 if (time_after(icsk->icsk_ack.timeout, jiffies)) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300110 sk_reset_timer(sk, &icsk->icsk_delack_timer,
111 icsk->icsk_ack.timeout);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700112 goto out;
113 }
114
115 icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
116
117 if (inet_csk_ack_scheduled(sk)) {
118 if (!icsk->icsk_ack.pingpong) {
119 /* Delayed ACK missed: inflate ATO. */
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300120 icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
121 icsk->icsk_rto);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700122 } else {
123 /* Delayed ACK missed: leave pingpong mode and
124 * deflate ATO.
125 */
126 icsk->icsk_ack.pingpong = 0;
127 icsk->icsk_ack.ato = TCP_ATO_MIN;
128 }
129 dccp_send_ack(sk);
130 NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS);
131 }
132out:
133 bh_unlock_sock(sk);
134 sock_put(sk);
135}
136
137/*
138 * The DCCP retransmit timer.
139 */
140static void dccp_retransmit_timer(struct sock *sk)
141{
142 struct inet_connection_sock *icsk = inet_csk(sk);
143
Andrea Bittauafe00252006-03-20 17:43:56 -0800144 /* retransmit timer is used for feature negotiation throughout
145 * connection. In this case, no packet is re-transmitted, but rather an
146 * ack is generated and pending changes are splaced into its options.
147 */
148 if (sk->sk_send_head == NULL) {
149 dccp_pr_debug("feat negotiation retransmit timeout %p\n", sk);
150 if (sk->sk_state == DCCP_OPEN)
151 dccp_send_ack(sk);
152 goto backoff;
153 }
154
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700155 /*
156 * sk->sk_send_head has to have one skb with
157 * DCCP_SKB_CB(skb)->dccpd_type set to one of the retransmittable DCCP
Arnaldo Carvalho de Melo03ace392005-08-21 05:36:45 -0300158 * packet types (REQUEST, RESPONSE, the ACK in the 3way handshake
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700159 * (PARTOPEN timer), etc).
160 */
161 BUG_TRAP(sk->sk_send_head != NULL);
162
163 /*
164 * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was
165 * sent, no need to retransmit, this sock is dead.
166 */
167 if (dccp_write_timeout(sk))
168 goto out;
169
170 /*
171 * We want to know the number of packets retransmitted, not the
172 * total number of retransmissions of clones of original packets.
173 */
174 if (icsk->icsk_retransmits == 0)
175 DCCP_INC_STATS_BH(DCCP_MIB_TIMEOUTS);
176
177 if (dccp_retransmit_skb(sk, sk->sk_send_head) < 0) {
178 /*
179 * Retransmission failed because of local congestion,
180 * do not backoff.
181 */
182 if (icsk->icsk_retransmits == 0)
183 icsk->icsk_retransmits = 1;
184 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
185 min(icsk->icsk_rto,
186 TCP_RESOURCE_PROBE_INTERVAL),
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300187 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700188 goto out;
189 }
190
Andrea Bittauafe00252006-03-20 17:43:56 -0800191backoff:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700192 icsk->icsk_backoff++;
193 icsk->icsk_retransmits++;
194
195 icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300196 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto,
197 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700198 if (icsk->icsk_retransmits > 3 /* FIXME: sysctl_dccp_retries1 */)
199 __sk_dst_reset(sk);
200out:;
201}
202
203static void dccp_write_timer(unsigned long data)
204{
205 struct sock *sk = (struct sock *)data;
206 struct inet_connection_sock *icsk = inet_csk(sk);
207 int event = 0;
208
209 bh_lock_sock(sk);
210 if (sock_owned_by_user(sk)) {
211 /* Try again later */
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300212 sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
213 jiffies + (HZ / 20));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700214 goto out;
215 }
216
217 if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending)
218 goto out;
219
220 if (time_after(icsk->icsk_timeout, jiffies)) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300221 sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
222 icsk->icsk_timeout);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700223 goto out;
224 }
225
226 event = icsk->icsk_pending;
227 icsk->icsk_pending = 0;
228
229 switch (event) {
230 case ICSK_TIME_RETRANS:
231 dccp_retransmit_timer(sk);
232 break;
233 }
234out:
235 bh_unlock_sock(sk);
236 sock_put(sk);
237}
238
239/*
240 * Timer for listening sockets
241 */
242static void dccp_response_timer(struct sock *sk)
243{
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300244 inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, DCCP_TIMEOUT_INIT,
245 DCCP_RTO_MAX);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700246}
247
248static void dccp_keepalive_timer(unsigned long data)
249{
250 struct sock *sk = (struct sock *)data;
251
252 /* Only process if socket is not in use. */
253 bh_lock_sock(sk);
254 if (sock_owned_by_user(sk)) {
255 /* Try again later. */
256 inet_csk_reset_keepalive_timer(sk, HZ / 20);
257 goto out;
258 }
259
260 if (sk->sk_state == DCCP_LISTEN) {
261 dccp_response_timer(sk);
262 goto out;
263 }
264out:
265 bh_unlock_sock(sk);
266 sock_put(sk);
267}