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