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 #pragma once 18 19 #include <stdbool.h> 20 #include <stdint.h> 21 #include <sys/socket.h> 22 #include <time.h> 23 24 #include "params.h" 25 26 #define RCODE_INTERNAL_ERROR 254 27 #define RCODE_TIMEOUT 255 28 29 struct res_sample { 30 time_t at; // time in s at which the sample was recorded 31 uint16_t rtt; // round-trip time in ms 32 uint8_t rcode; // the DNS rcode or RCODE_XXX defined above 33 }; 34 35 // Resolver reachability statistics and run-time parameters. 36 struct res_stats { 37 // Stats of the last <sample_count> queries. 38 res_sample samples[MAXNSSAMPLES]; 39 // The number of samples stored. 40 uint8_t sample_count; 41 // The next sample to modify. 42 uint8_t sample_next; 43 }; 44 45 // Aggregates the reachability statistics for the given server based on on the stored samples. 46 void android_net_res_stats_aggregate(res_stats* stats, int* successes, int* errors, int* timeouts, 47 int* internal_errors, int* rtt_avg, time_t* last_sample_time); 48 49 int android_net_res_stats_get_info_for_net(unsigned netid, int* nscount, 50 sockaddr_storage servers[MAXNS], int* dcount, 51 char domains[MAXDNSRCH][MAXDNSRCHPATH], 52 res_params* params, res_stats stats[MAXNS], 53 int* wait_for_pending_req_timeout_count); 54 55 // Returns an array of bools indicating which servers are considered good 56 int android_net_res_stats_get_usable_servers(const res_params* params, res_stats stats[], 57 int nscount, bool valid_servers[]); 58 59 // Calculate the round-trip-time from start time t0 and end time t1. 60 int res_stats_calculate_rtt(const timespec* t1, const timespec* t0); 61 62 // Create a sample for calculating server reachability statistics. 63 void res_stats_set_sample(res_sample* sample, time_t now, int rcode, int rtt); 64