6b3f0d65f2
Collect statistics about DNS query success state and delay. Ignore servers that have been tried at least five times and have a success rate of < 0.25. Retry these servers once every 180s. Bug: 25731675 Change-Id: I78e24f43e388dca82fb81835e1796f4c7dce8da3
44 lines
1.7 KiB
C
44 lines
1.7 KiB
C
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _RESOLV_PARAMS_H
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#define _RESOLV_PARAMS_H
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#include <stdint.h>
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/* Hard-coded defines */
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#define MAXNS 3 /* max # name servers we'll track */
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#define MAXNSSAMPLES 64 /* max # samples to store per server */
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/* Defaults used for initializing __res_params */
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#define SUCCESS_THRESHOLD 75 /* if successes * 100 / total_samples is less than
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* this value, the server is considered failing
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*/
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#define NSSAMPLE_VALIDITY 1800 /* Sample validity in seconds.
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* Set to -1 to disable skipping failing
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* servers.
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*/
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/* per-netid configuration parameters passed from netd to the resolver */
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struct __res_params {
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uint16_t sample_validity; // sample lifetime in s
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// threshold of success / total samples below which a server is considered broken
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uint8_t success_threshold; // 0: disable, value / 100 otherwise
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uint8_t min_samples; // min # samples needed for statistics to be considered meaningful
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uint8_t max_samples; // max # samples taken into account for statistics
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} __attribute__((__packed__));
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#endif // _RESOLV_PARAMS_H
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