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[/] [test_project/] [trunk/] [linux_sd_driver/] [net/] [dccp/] [timer.c] - Blame information for rev 62

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Line No. Rev Author Line
1 62 marcus.erl
/*
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/dccp.h>
14
#include <linux/skbuff.h>
15
 
16
#include "dccp.h"
17
 
18
/* sysctl variables governing numbers of retransmission attempts */
19
int  sysctl_dccp_request_retries        __read_mostly = TCP_SYN_RETRIES;
20
int  sysctl_dccp_retries1               __read_mostly = TCP_RETR1;
21
int  sysctl_dccp_retries2               __read_mostly = TCP_RETR2;
22
 
23
static void dccp_write_err(struct sock *sk)
24
{
25
        sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
26
        sk->sk_error_report(sk);
27
 
28
        dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
29
        dccp_done(sk);
30
        DCCP_INC_STATS_BH(DCCP_MIB_ABORTONTIMEOUT);
31
}
32
 
33
/* A write timeout has occurred. Process the after effects. */
34
static 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)
41
                        dst_negative_advice(&sk->sk_dst_cache);
42
                retry_until = icsk->icsk_syn_retries ?
43
                            : sysctl_dccp_request_retries;
44
        } else {
45
                if (icsk->icsk_retransmits >= sysctl_dccp_retries1) {
46
                        /* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu
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                           black hole detection. :-(
48
 
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
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   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
 
63
                           Golden words :-).
64
                   */
65
 
66
                        dst_negative_advice(&sk->sk_dst_cache);
67
                }
68
 
69
                retry_until = sysctl_dccp_retries2;
70
                /*
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
 
83
/*
84
 *      The DCCP retransmit timer.
85
 */
86
static void dccp_retransmit_timer(struct sock *sk)
87
{
88
        struct inet_connection_sock *icsk = inet_csk(sk);
89
 
90
        /* retransmit timer is used for feature negotiation throughout
91
         * connection.  In this case, no packet is re-transmitted, but rather an
92
         * ack is generated and pending changes are placed into its options.
93
         */
94
        if (sk->sk_send_head == NULL) {
95
                dccp_pr_debug("feat negotiation retransmit timeout %p\n", sk);
96
                if (sk->sk_state == DCCP_OPEN)
97
                        dccp_send_ack(sk);
98
                goto backoff;
99
        }
100
 
101
        /*
102
         * sk->sk_send_head has to have one skb with
103
         * DCCP_SKB_CB(skb)->dccpd_type set to one of the retransmittable DCCP
104
         * packet types. The only packets eligible for retransmission are:
105
         *      -- Requests in client-REQUEST  state (sec. 8.1.1)
106
         *      -- Acks     in client-PARTOPEN state (sec. 8.1.5)
107
         *      -- CloseReq in server-CLOSEREQ state (sec. 8.3)
108
         *      -- Close    in   node-CLOSING  state (sec. 8.3)                */
109
        BUG_TRAP(sk->sk_send_head != NULL);
110
 
111
        /*
112
         * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was
113
         * sent, no need to retransmit, this sock is dead.
114
         */
115
        if (dccp_write_timeout(sk))
116
                goto out;
117
 
118
        /*
119
         * We want to know the number of packets retransmitted, not the
120
         * total number of retransmissions of clones of original packets.
121
         */
122
        if (icsk->icsk_retransmits == 0)
123
                DCCP_INC_STATS_BH(DCCP_MIB_TIMEOUTS);
124
 
125
        if (dccp_retransmit_skb(sk, sk->sk_send_head) < 0) {
126
                /*
127
                 * Retransmission failed because of local congestion,
128
                 * do not backoff.
129
                 */
130
                if (icsk->icsk_retransmits == 0)
131
                        icsk->icsk_retransmits = 1;
132
                inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
133
                                          min(icsk->icsk_rto,
134
                                              TCP_RESOURCE_PROBE_INTERVAL),
135
                                          DCCP_RTO_MAX);
136
                goto out;
137
        }
138
 
139
backoff:
140
        icsk->icsk_backoff++;
141
        icsk->icsk_retransmits++;
142
 
143
        icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX);
144
        inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto,
145
                                  DCCP_RTO_MAX);
146
        if (icsk->icsk_retransmits > sysctl_dccp_retries1)
147
                __sk_dst_reset(sk);
148
out:;
149
}
150
 
151
static void dccp_write_timer(unsigned long data)
152
{
153
        struct sock *sk = (struct sock *)data;
154
        struct inet_connection_sock *icsk = inet_csk(sk);
155
        int event = 0;
156
 
157
        bh_lock_sock(sk);
158
        if (sock_owned_by_user(sk)) {
159
                /* Try again later */
160
                sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
161
                               jiffies + (HZ / 20));
162
                goto out;
163
        }
164
 
165
        if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending)
166
                goto out;
167
 
168
        if (time_after(icsk->icsk_timeout, jiffies)) {
169
                sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
170
                               icsk->icsk_timeout);
171
                goto out;
172
        }
173
 
174
        event = icsk->icsk_pending;
175
        icsk->icsk_pending = 0;
176
 
177
        switch (event) {
178
        case ICSK_TIME_RETRANS:
179
                dccp_retransmit_timer(sk);
180
                break;
181
        }
182
out:
183
        bh_unlock_sock(sk);
184
        sock_put(sk);
185
}
186
 
187
/*
188
 *      Timer for listening sockets
189
 */
190
static void dccp_response_timer(struct sock *sk)
191
{
192
        inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, DCCP_TIMEOUT_INIT,
193
                                   DCCP_RTO_MAX);
194
}
195
 
196
static void dccp_keepalive_timer(unsigned long data)
197
{
198
        struct sock *sk = (struct sock *)data;
199
 
200
        /* Only process if socket is not in use. */
201
        bh_lock_sock(sk);
202
        if (sock_owned_by_user(sk)) {
203
                /* Try again later. */
204
                inet_csk_reset_keepalive_timer(sk, HZ / 20);
205
                goto out;
206
        }
207
 
208
        if (sk->sk_state == DCCP_LISTEN) {
209
                dccp_response_timer(sk);
210
                goto out;
211
        }
212
out:
213
        bh_unlock_sock(sk);
214
        sock_put(sk);
215
}
216
 
217
/* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */
218
static void dccp_delack_timer(unsigned long data)
219
{
220
        struct sock *sk = (struct sock *)data;
221
        struct inet_connection_sock *icsk = inet_csk(sk);
222
 
223
        bh_lock_sock(sk);
224
        if (sock_owned_by_user(sk)) {
225
                /* Try again later. */
226
                icsk->icsk_ack.blocked = 1;
227
                NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED);
228
                sk_reset_timer(sk, &icsk->icsk_delack_timer,
229
                               jiffies + TCP_DELACK_MIN);
230
                goto out;
231
        }
232
 
233
        if (sk->sk_state == DCCP_CLOSED ||
234
            !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
235
                goto out;
236
        if (time_after(icsk->icsk_ack.timeout, jiffies)) {
237
                sk_reset_timer(sk, &icsk->icsk_delack_timer,
238
                               icsk->icsk_ack.timeout);
239
                goto out;
240
        }
241
 
242
        icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
243
 
244
        if (inet_csk_ack_scheduled(sk)) {
245
                if (!icsk->icsk_ack.pingpong) {
246
                        /* Delayed ACK missed: inflate ATO. */
247
                        icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
248
                                                 icsk->icsk_rto);
249
                } else {
250
                        /* Delayed ACK missed: leave pingpong mode and
251
                         * deflate ATO.
252
                         */
253
                        icsk->icsk_ack.pingpong = 0;
254
                        icsk->icsk_ack.ato = TCP_ATO_MIN;
255
                }
256
                dccp_send_ack(sk);
257
                NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS);
258
        }
259
out:
260
        bh_unlock_sock(sk);
261
        sock_put(sk);
262
}
263
 
264
/* Transmit-delay timer: used by the CCIDs to delay actual send time */
265
static void dccp_write_xmit_timer(unsigned long data)
266
{
267
        struct sock *sk = (struct sock *)data;
268
        struct dccp_sock *dp = dccp_sk(sk);
269
 
270
        bh_lock_sock(sk);
271
        if (sock_owned_by_user(sk))
272
                sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);
273
        else
274
                dccp_write_xmit(sk, 0);
275
        bh_unlock_sock(sk);
276
        sock_put(sk);
277
}
278
 
279
static void dccp_init_write_xmit_timer(struct sock *sk)
280
{
281
        struct dccp_sock *dp = dccp_sk(sk);
282
 
283
        init_timer(&dp->dccps_xmit_timer);
284
        dp->dccps_xmit_timer.data = (unsigned long)sk;
285
        dp->dccps_xmit_timer.function = dccp_write_xmit_timer;
286
}
287
 
288
void dccp_init_xmit_timers(struct sock *sk)
289
{
290
        dccp_init_write_xmit_timer(sk);
291
        inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer,
292
                                  &dccp_keepalive_timer);
293
}
294
 
295
static ktime_t dccp_timestamp_seed;
296
/**
297
 * dccp_timestamp  -  10s of microseconds time source
298
 * Returns the number of 10s of microseconds since loading DCCP. This is native
299
 * DCCP time difference format (RFC 4340, sec. 13).
300
 * Please note: This will wrap around about circa every 11.9 hours.
301
 */
302
u32 dccp_timestamp(void)
303
{
304
        s64 delta = ktime_us_delta(ktime_get_real(), dccp_timestamp_seed);
305
 
306
        do_div(delta, 10);
307
        return delta;
308
}
309
EXPORT_SYMBOL_GPL(dccp_timestamp);
310
 
311
void __init dccp_timestamping_init(void)
312
{
313
        dccp_timestamp_seed = ktime_get_real();
314
}

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