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 _RESOLVER_STATS_H_
18 #define _RESOLVER_STATS_H_
19
20 #include <time.h>
21
22 namespace android {
23 namespace net {
24
25 struct ResolverStats {
26 // Offsets into the per-server resolver stats as encoded in vector<int32_t> stats of
27 // getResolverInfo() of Netd's binder interface. The stats are based on data reported by
28 // android_net_res_stats_get_info_for_net(), the usability is calculated by applying
29 // android_net_res_stats_get_usable_servers() to this data.
30 enum ResolverStatsOffsets {
31 STATS_SUCCESSES = 0, // # successes counted for this server
32 STATS_ERRORS, // # errors
33 STATS_TIMEOUTS, // # timeouts
34 STATS_INTERNAL_ERRORS, // # internal errors
35 STATS_RTT_AVG, // average round-trip-time
36 STATS_LAST_SAMPLE_TIME, // time in s when the last sample was recorded
37 STATS_USABLE, // whether the server is considered usable
38 STATS_COUNT // total count of integers in the per-server data
39 };
40
41 int successes{-1};
42 int errors{-1};
43 int timeouts{-1};
44 int internal_errors{-1};
45 int rtt_avg{-1};
46 time_t last_sample_time{0};
47 bool usable{false};
48
49 // Serialize the resolver stats to the end of |out|.
50 void encode(std::vector<int32_t>* out) const;
51
52 // Read the serialized resolverstats starting at |in[ofs]|.
53 ssize_t decode(const std::vector<int32_t>& in, ssize_t ofs);
54
55 // Serialize the contents of |stats| and append them to the end of |out|. Multiple arrays
56 // can be written to the same output vector in sequence, however, the corresponding call
57 // to decodeAll() will return the combined contents in one vector.
58 static void encodeAll(const std::vector<ResolverStats>& stats, std::vector<int32_t>* out);
59
60 // Decodes the serialized ResolverStats from |in| and appends them to stats.
61 static bool decodeAll(const std::vector<int32_t>& in, std::vector<ResolverStats>* stats);
62 };
63
encode(std::vector<int32_t> * out)64 inline void ResolverStats::encode(std::vector<int32_t>* out) const {
65 size_t ofs = out->size();
66 out->resize(ofs + STATS_COUNT);
67 int32_t* cur = &(*out)[ofs];
68 cur[STATS_SUCCESSES] = successes;
69 cur[STATS_ERRORS] = errors;
70 cur[STATS_TIMEOUTS] = timeouts;
71 cur[STATS_INTERNAL_ERRORS] = internal_errors;
72 cur[STATS_RTT_AVG] = rtt_avg;
73 cur[STATS_LAST_SAMPLE_TIME] = last_sample_time;
74 cur[STATS_USABLE] = usable;
75 }
76
77 // Read the serialized resolverstats starting at |in[ofs]|.
decode(const std::vector<int32_t> & in,ssize_t ofs)78 inline ssize_t ResolverStats::decode(const std::vector<int32_t>& in, ssize_t ofs) {
79 if (ofs < 0 || static_cast<size_t>(ofs) + STATS_COUNT > in.size()) {
80 return -1;
81 }
82 const int32_t* cur = &in[ofs];
83 successes = cur[STATS_SUCCESSES];
84 errors = cur[STATS_ERRORS];
85 timeouts = cur[STATS_TIMEOUTS];
86 internal_errors = cur[STATS_INTERNAL_ERRORS];
87 rtt_avg = cur[STATS_RTT_AVG];
88 last_sample_time = cur[STATS_LAST_SAMPLE_TIME];
89 usable = cur[STATS_USABLE];
90 return ofs + STATS_COUNT;
91 }
92
encodeAll(const std::vector<ResolverStats> & stats,std::vector<int32_t> * out)93 inline void ResolverStats::encodeAll(const std::vector<ResolverStats>& stats,
94 std::vector<int32_t>* out) {
95 for (const auto& s : stats) {
96 s.encode(out);
97 }
98 }
99
100 // TODO: Replace with a better representation, e.g. a Parcelable.
decodeAll(const std::vector<int32_t> & in,std::vector<ResolverStats> * stats)101 inline bool ResolverStats::decodeAll(const std::vector<int32_t>& in,
102 std::vector<ResolverStats>* stats) {
103 ssize_t size = in.size();
104 if (size % STATS_COUNT) {
105 return false;
106 }
107 stats->resize(size / STATS_COUNT);
108 ssize_t ofs = 0;
109 for (auto& s : *stats) {
110 ofs = s.decode(in, ofs);
111 if (ofs < 0) {
112 return false;
113 }
114 }
115 return true;
116 }
117
118 } // namespace net
119 } // namespace android
120
121 #endif /* _RESOLVER_STATS_H_ */
122