1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef _RESOLV_PARAMS_H 18 #define _RESOLV_PARAMS_H 19 20 #include <stdint.h> 21 22 /* Hard-coded defines */ 23 #define MAXNS 4 /* max # name servers we'll track */ 24 #define MAXDNSRCH 6 /* max # domains in search path */ 25 #define MAXDNSRCHPATH 256 /* max length of domain search paths */ 26 #define MAXNSSAMPLES 64 /* max # samples to store per server */ 27 28 /* Defaults used for initializing __res_params */ 29 #define SUCCESS_THRESHOLD 75 /* if successes * 100 / total_samples is less than 30 * this value, the server is considered failing 31 */ 32 #define NSSAMPLE_VALIDITY 1800 /* Sample validity in seconds. 33 * Set to -1 to disable skipping failing 34 * servers. 35 */ 36 37 /* per-netid configuration parameters passed from netd to the resolver */ 38 struct __res_params { 39 uint16_t sample_validity; // sample lifetime in s 40 // threshold of success / total samples below which a server is considered broken 41 uint8_t success_threshold; // 0: disable, value / 100 otherwise 42 uint8_t min_samples; // min # samples needed for statistics to be considered meaningful 43 uint8_t max_samples; // max # samples taken into account for statistics 44 }; 45 46 typedef enum { res_goahead, res_nextns, res_modified, res_done, res_error } 47 res_sendhookact; 48 49 typedef res_sendhookact (*res_send_qhook)(struct sockaddr * const *, 50 const u_char **, int *, 51 u_char *, int, int *); 52 53 typedef res_sendhookact (*res_send_rhook)(const struct sockaddr *, 54 const u_char *, int, u_char *, 55 int, int *); 56 57 #endif // _RESOLV_PARAMS_H 58