/*
 * 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.
 */

#define LOG_TAG "connect_benchmark"

/*
 * See README.md for general notes.
 *
 * This set of benchmarks measures the throughput of connect() calls on a single thread for IPv4 and
 * IPv6.
 *
 * Realtime timed tests
 * ====================
 *
 * The tests named *_high_load record the following useful information:
 *
 *   - real_time: the mean roundtrip time for one connect() call under load
 *
 *   - iterations: the number of times the test was run within the timelimit --- approximately
 *                 MinTime / real_time
 *
 * Manually timed tests
 * ====================
 *
 * All other sets of tests apart from *_high_load run with manual timing. The purpose of these is to
 * measure 90th-percentile latency for connect() calls compared to mean latency.
 *
 * (TODO: ideally this should be against median latency, but google-benchmark only supports one
 *        custom 'label' output for graphing. Stddev isn't appropriate because the latency
 *        distribution is usually spiky, not in a nice neat normal-like distribution.)
 *
 * The manually timed tests record the following useful information:
 *
 *  - real_time: the average time taken to complete a test run. Unlike the real_time used in high
 *               load tests, this is calculated from before-and-after values of the realtime clock
 *               over many iterations so may be less accurate than the under-load times.
 *
 *  - iterations: the number of times the test was run within the timelimit --- approximately
 *                MinTime / real_time, although as explained, may not be as meaningful because of
 *                overhead from timing.
 *
 *  - label: a manually-recorded time giving the 90th-percentile value of real_time over all
 *           individual runs. Should be compared to real_time.
 *
 */

#include <arpa/inet.h>
#include <cutils/sockets.h>
#include <errno.h>
#include <netinet/in.h>
#include <time.h>

#include <map>
#include <functional>
#include <thread>

#include <android-base/stringprintf.h>
#include <benchmark/benchmark.h>
#include <log/log.h>
#include <netdutils/Stopwatch.h>
#include <utils/StrongPointer.h>

#include "FwmarkClient.h"
#include "SockDiag.h"

using android::base::StringPrintf;
using android::netdutils::Stopwatch;

static int bindAndListen(int s) {
    sockaddr_in6 sin6 = { .sin6_family = AF_INET6 };
    if (bind(s, (sockaddr*) &sin6, sizeof(sin6)) == 0) {
        if (listen(s, 1)) {
            return -1;
        }
        sockaddr_in sin = {};
        socklen_t len = sizeof(sin);
        if (getsockname(s, (sockaddr*) &sin, &len)) {
            return -1;
        }
        return ntohs(sin.sin_port);
    } else {
        return -1;
    }
}

static void ipv4_loopback(benchmark::State& state, const bool waitBetweenRuns) {
    const int listensocket = socket(AF_INET6, SOCK_STREAM | SOCK_CLOEXEC, 0);
    const int port = bindAndListen(listensocket);
    if (port == -1) {
        state.SkipWithError("Unable to bind server socket");
        return;
    }

    // ALOGW("Listening on port = %d", port);
    std::vector<uint64_t> latencies(state.max_iterations);
    uint64_t iterations = 0;

    while (state.KeepRunning()) {
        int sock = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
        if (sock < 0) {
            state.SkipWithError(StringPrintf("socket() failed with errno=%d", errno).c_str());
            break;
        }

        const Stopwatch stopwatch;

        sockaddr_in server = { .sin_family = AF_INET, .sin_port = htons(port) };
        if (connect(sock, (sockaddr*) &server, sizeof(server))) {
            state.SkipWithError(StringPrintf("connect() failed with errno=%d", errno).c_str());
            close(sock);
            break;
        }

        if (waitBetweenRuns) {
            latencies[iterations] = stopwatch.timeTakenUs();
            state.SetIterationTime(static_cast<double>(latencies[iterations]) / 1.0e6L);
            std::this_thread::sleep_for(std::chrono::milliseconds(10));
            ++iterations;
        }

        sockaddr_in6 client;
        socklen_t clientlen = sizeof(client);
        int accepted = accept4(listensocket, (sockaddr*) &client, &clientlen, SOCK_CLOEXEC);
        if (accepted < 0) {
            state.SkipWithError(StringPrintf("accept() failed with errno=%d", errno).c_str());
            close(sock);
            break;
        }

        close(accepted);
        close(sock);
    }
    close(listensocket);
    // ALOGI("Finished test on port = %d", port);

    if (iterations > 0) {
        latencies.resize(iterations);
        sort(latencies.begin(), latencies.end());
        state.SetLabel(StringPrintf("%lld", (long long) latencies[iterations * 9 / 10]));
    }
}

static void ipv6_loopback(benchmark::State& state, const bool waitBetweenRuns) {
    const int listensocket = socket(AF_INET6, SOCK_STREAM | SOCK_CLOEXEC, 0);
    const int port = bindAndListen(listensocket);
    if (port == -1) {
        state.SkipWithError("Unable to bind server socket");
        return;
    }

    // ALOGW("Listening on port = %d", port);
    std::vector<uint64_t> latencies(state.max_iterations);
    uint64_t iterations = 0;

    while (state.KeepRunning()) {
        int sock = socket(AF_INET6, SOCK_STREAM | SOCK_CLOEXEC, 0);
        if (sock < 0) {
            state.SkipWithError(StringPrintf("socket() failed with errno=%d", errno).c_str());
            break;
        }

        const Stopwatch stopwatch;

        sockaddr_in6 server = { .sin6_family = AF_INET6, .sin6_port = htons(port) };
        if (connect(sock, (sockaddr*) &server, sizeof(server))) {
            state.SkipWithError(StringPrintf("connect() failed with errno=%d", errno).c_str());
            close(sock);
            break;
        }

        if (waitBetweenRuns) {
            latencies[iterations] = stopwatch.timeTakenUs();
            state.SetIterationTime(static_cast<double>(latencies[iterations]) / 1.0e6L);
            std::this_thread::sleep_for(std::chrono::milliseconds(10));
            ++iterations;
        }

        sockaddr_in6 client;
        socklen_t clientlen = sizeof(client);
        int accepted = accept4(listensocket, (sockaddr*) &client, &clientlen, SOCK_CLOEXEC);
        if (accepted < 0) {
            state.SkipWithError(StringPrintf("accept() failed with errno=%d", errno).c_str());
            close(sock);
            break;
        }

        close(accepted);
        close(sock);
    }
    close(listensocket);
    // ALOGI("Finished test on port = %d", port);

    if (iterations > 0) {
        latencies.resize(iterations);
        sort(latencies.begin(), latencies.end());
        state.SetLabel(StringPrintf("%lld", (long long) latencies[iterations * 9 / 10]));
    }
}

static void run(decltype(ipv4_loopback) benchmarkFunction, ::benchmark::State& state,
                const bool waitBetweenRuns) {
    benchmarkFunction(state, waitBetweenRuns);
}

constexpr int MIN_THREADS = 1;
constexpr int MAX_THREADS = 1;
constexpr double MIN_TIME = 0.5 /* seconds */;

// IPv4 benchmarks under no load
static void ipv4_no_load(::benchmark::State& state) {
    run(ipv4_loopback, state, true);
}
BENCHMARK(ipv4_no_load)->MinTime(MIN_TIME)->UseManualTime();

// IPv4 benchmarks under high load
static void ipv4_high_load(::benchmark::State& state) {
    run(ipv4_loopback, state, false);
}
BENCHMARK(ipv4_high_load)->ThreadRange(MIN_THREADS, MAX_THREADS)->MinTime(MIN_TIME)->UseRealTime();

// IPv6 raw connect() without using fwmark
static void ipv6_no_load(::benchmark::State& state) {
    run(ipv6_loopback, state, true);
}
BENCHMARK(ipv6_no_load)->MinTime(MIN_TIME)->UseManualTime();

// IPv6 benchmarks under high load
static void ipv6_high_load(::benchmark::State& state) {
    run(ipv6_loopback, state, false);
}
BENCHMARK(ipv6_high_load)->ThreadRange(MIN_THREADS, MAX_THREADS)->MinTime(MIN_TIME)->UseRealTime();