aosp12/packages/modules/DnsResolver/ResolverStats.h

122 lines
4.3 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 _RESOLVER_STATS_H_
#define _RESOLVER_STATS_H_
#include <time.h>
namespace android {
namespace net {
struct ResolverStats {
// Offsets into the per-server resolver stats as encoded in vector<int32_t> stats of
// getResolverInfo() of Netd's binder interface. The stats are based on data reported by
// android_net_res_stats_get_info_for_net(), the usability is calculated by applying
// android_net_res_stats_get_usable_servers() to this data.
enum ResolverStatsOffsets {
STATS_SUCCESSES = 0, // # successes counted for this server
STATS_ERRORS, // # errors
STATS_TIMEOUTS, // # timeouts
STATS_INTERNAL_ERRORS, // # internal errors
STATS_RTT_AVG, // average round-trip-time
STATS_LAST_SAMPLE_TIME, // time in s when the last sample was recorded
STATS_USABLE, // whether the server is considered usable
STATS_COUNT // total count of integers in the per-server data
};
int successes{-1};
int errors{-1};
int timeouts{-1};
int internal_errors{-1};
int rtt_avg{-1};
time_t last_sample_time{0};
bool usable{false};
// Serialize the resolver stats to the end of |out|.
void encode(std::vector<int32_t>* out) const;
// Read the serialized resolverstats starting at |in[ofs]|.
ssize_t decode(const std::vector<int32_t>& in, ssize_t ofs);
// Serialize the contents of |stats| and append them to the end of |out|. Multiple arrays
// can be written to the same output vector in sequence, however, the corresponding call
// to decodeAll() will return the combined contents in one vector.
static void encodeAll(const std::vector<ResolverStats>& stats, std::vector<int32_t>* out);
// Decodes the serialized ResolverStats from |in| and appends them to stats.
static bool decodeAll(const std::vector<int32_t>& in, std::vector<ResolverStats>* stats);
};
inline void ResolverStats::encode(std::vector<int32_t>* out) const {
size_t ofs = out->size();
out->resize(ofs + STATS_COUNT);
int32_t* cur = &(*out)[ofs];
cur[STATS_SUCCESSES] = successes;
cur[STATS_ERRORS] = errors;
cur[STATS_TIMEOUTS] = timeouts;
cur[STATS_INTERNAL_ERRORS] = internal_errors;
cur[STATS_RTT_AVG] = rtt_avg;
cur[STATS_LAST_SAMPLE_TIME] = last_sample_time;
cur[STATS_USABLE] = usable;
}
// Read the serialized resolverstats starting at |in[ofs]|.
inline ssize_t ResolverStats::decode(const std::vector<int32_t>& in, ssize_t ofs) {
if (ofs < 0 || static_cast<size_t>(ofs) + STATS_COUNT > in.size()) {
return -1;
}
const int32_t* cur = &in[ofs];
successes = cur[STATS_SUCCESSES];
errors = cur[STATS_ERRORS];
timeouts = cur[STATS_TIMEOUTS];
internal_errors = cur[STATS_INTERNAL_ERRORS];
rtt_avg = cur[STATS_RTT_AVG];
last_sample_time = cur[STATS_LAST_SAMPLE_TIME];
usable = cur[STATS_USABLE];
return ofs + STATS_COUNT;
}
inline void ResolverStats::encodeAll(const std::vector<ResolverStats>& stats,
std::vector<int32_t>* out) {
for (const auto& s : stats) {
s.encode(out);
}
}
// TODO: Replace with a better representation, e.g. a Parcelable.
inline bool ResolverStats::decodeAll(const std::vector<int32_t>& in,
std::vector<ResolverStats>* stats) {
ssize_t size = in.size();
if (size % STATS_COUNT) {
return false;
}
stats->resize(size / STATS_COUNT);
ssize_t ofs = 0;
for (auto& s : *stats) {
ofs = s.decode(in, ofs);
if (ofs < 0) {
return false;
}
}
return true;
}
} // namespace net
} // namespace android
#endif /* _RESOLVER_STATS_H_ */