platform_bionic/libc/dns/include/resolv_params.h
Pierre Imai fff356786f Store DNS server count in resolv_cache.
Instead of keeping a sentinel after nameservers[], nsaddrinfo[] and
nstats[], store the server count in the structure, freeing up memory and
eliminating the need to enumerate the server count every time
_resolv_is_nameservers_equal_locked() is invoked.

Also increase MAXNS from 3 to 4.

BUG: 28153323
Change-Id: I11a7257af695157c9e32019cd00c67b535b63c75
2016-04-21 10:07:24 +09:00

44 lines
1.7 KiB
C

/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _RESOLV_PARAMS_H
#define _RESOLV_PARAMS_H
#include <stdint.h>
/* Hard-coded defines */
#define MAXNS 4 /* max # name servers we'll track */
#define MAXNSSAMPLES 64 /* max # samples to store per server */
/* Defaults used for initializing __res_params */
#define SUCCESS_THRESHOLD 75 /* if successes * 100 / total_samples is less than
* this value, the server is considered failing
*/
#define NSSAMPLE_VALIDITY 1800 /* Sample validity in seconds.
* Set to -1 to disable skipping failing
* servers.
*/
/* per-netid configuration parameters passed from netd to the resolver */
struct __res_params {
uint16_t sample_validity; // sample lifetime in s
// threshold of success / total samples below which a server is considered broken
uint8_t success_threshold; // 0: disable, value / 100 otherwise
uint8_t min_samples; // min # samples needed for statistics to be considered meaningful
uint8_t max_samples; // max # samples taken into account for statistics
} __attribute__((__packed__));
#endif // _RESOLV_PARAMS_H