// Copyright (c) 2020-2022 The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <addrdb.h>

#include <addrman.h>

#include <addrman_impl.h>

#include <chainparams.h>

#include <common/args.h>

#include <merkleblock.h>

#include <random.h>

#include <test/fuzz/FuzzedDataProvider.h>

#include <test/fuzz/fuzz.h>

#include <test/fuzz/util.h>

#include <test/fuzz/util/net.h>

#include <test/util/setup_common.h>

#include <time.h>

#include <util/asmap.h>

#include <util/chaintype.h>

#include <cassert>

#include <cstdint>

#include <optional>

#include <string>

#include <vector>

namespace {

const BasicTestingSetup* g_setup;

int32_t GetCheckRatio()

{

    return std::clamp<int32_t>(g_setup->m_node.args->GetIntArg("-checkaddrman", 0), 0, 1000000);

}

} // namespace

void initialize_addrman()

{

    static const auto testing_setup = MakeNoLogFileContext<>(ChainType::REGTEST);

    g_setup = testing_setup.get();

}

FUZZ_TARGET(data_stream_addr_man, .init = initialize_addrman)

{

    SeedRandomStateForTest(SeedRand::ZEROS);

    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};

    DataStream data_stream = ConsumeDataStream(fuzzed_data_provider);

    NetGroupManager netgroupman{ConsumeNetGroupManager(fuzzed_data_provider)};

    AddrMan addr_man(netgroupman, /*deterministic=*/false, GetCheckRatio());

    try {

        ReadFromStream(addr_man, data_stream);

    } catch (const std::exception&) {

    }

}

/**

 * Generate a random address. Always returns a valid address.

 */

CNetAddr RandAddr(FuzzedDataProvider& fuzzed_data_provider, FastRandomContext& fast_random_context)

{

    CNetAddr addr;

    assert(!addr.IsValid());

    for (size_t i = 0; i < 8 && !addr.IsValid(); ++i) {

        if (fuzzed_data_provider.remaining_bytes() > 1 && fuzzed_data_provider.ConsumeBool()) {

            addr = ConsumeNetAddr(fuzzed_data_provider);

        } else {

            addr = ConsumeNetAddr(fuzzed_data_provider, &fast_random_context);

        }

    }

    // Return a dummy IPv4 5.5.5.5 if we generated an invalid address.

    if (!addr.IsValid()) {

        in_addr v4_addr = {};

        v4_addr.s_addr = 0x05050505;

        addr = CNetAddr{v4_addr};

    }

    return addr;

}

/** Fill addrman with lots of addresses from lots of sources.  */

void FillAddrman(AddrMan& addrman, FuzzedDataProvider& fuzzed_data_provider)

{

    // Add a fraction of the addresses to the "tried" table.

    // 0, 1, 2, 3 corresponding to 0%, 100%, 50%, 33%

    const size_t n = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 3);

    const size_t num_sources = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(1, 50);

    CNetAddr prev_source;

    // Generate a FastRandomContext seed to use inside the loops instead of

    // fuzzed_data_provider. When fuzzed_data_provider is exhausted it

    // just returns 0.

    FastRandomContext fast_random_context{ConsumeUInt256(fuzzed_data_provider)};

    for (size_t i = 0; i < num_sources; ++i) {

        const auto source = RandAddr(fuzzed_data_provider, fast_random_context);

        const size_t num_addresses = fast_random_context.randrange(500) + 1; // [1..500]

        for (size_t j = 0; j < num_addresses; ++j) {

            const auto addr = CAddress{CService{RandAddr(fuzzed_data_provider, fast_random_context), 8333}, NODE_NETWORK};

            const std::chrono::seconds time_penalty{fast_random_context.randrange(100000001)};

            addrman.Add({addr}, source, time_penalty);

            if (n > 0 && addrman.Size() % n == 0) {

                addrman.Good(addr, Now<NodeSeconds>());

            }

            // Add 10% of the addresses from more than one source.

            if (fast_random_context.randrange(10) == 0 && prev_source.IsValid()) {

                addrman.Add({addr}, prev_source, time_penalty);

            }

        }

        prev_source = source;

    }

}

FUZZ_TARGET(addrman, .init = initialize_addrman)

{

    SeedRandomStateForTest(SeedRand::ZEROS);

    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());

    SetMockTime(ConsumeTime(fuzzed_data_provider));

    NetGroupManager netgroupman{ConsumeNetGroupManager(fuzzed_data_provider)};

    auto addr_man_ptr = std::make_unique<AddrManDeterministic>(netgroupman, fuzzed_data_provider, GetCheckRatio());

    if (fuzzed_data_provider.ConsumeBool()) {

        const std::vector<uint8_t> serialized_data{ConsumeRandomLengthByteVector(fuzzed_data_provider)};

        DataStream ds{serialized_data};

        try {

            ds >> *addr_man_ptr;

        } catch (const std::ios_base::failure&) {

            addr_man_ptr = std::make_unique<AddrManDeterministic>(netgroupman, fuzzed_data_provider, GetCheckRatio());

        }

    }

    AddrManDeterministic& addr_man = *addr_man_ptr;

    LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000) {

        CallOneOf(

            fuzzed_data_provider,

            [&] {

                addr_man.ResolveCollisions();

            },

            [&] {

                (void)addr_man.SelectTriedCollision();

            },

            [&] {

                std::vector<CAddress> addresses;

                LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000) {

                    addresses.push_back(ConsumeAddress(fuzzed_data_provider));

                }

                auto net_addr = ConsumeNetAddr(fuzzed_data_provider);

                auto time_penalty = std::chrono::seconds{ConsumeTime(fuzzed_data_provider, 0, 100000000)};

                addr_man.Add(addresses, net_addr, time_penalty);

            },

            [&] {

                auto addr = ConsumeService(fuzzed_data_provider);

                auto time = NodeSeconds{std::chrono::seconds{ConsumeTime(fuzzed_data_provider)}};

                addr_man.Good(addr, time);

            },

            [&] {

                auto addr = ConsumeService(fuzzed_data_provider);

                auto count_failure = fuzzed_data_provider.ConsumeBool();

                auto time = NodeSeconds{std::chrono::seconds{ConsumeTime(fuzzed_data_provider)}};

                addr_man.Attempt(addr, count_failure, time);

            },

            [&] {

                auto addr = ConsumeService(fuzzed_data_provider);

                auto time = NodeSeconds{std::chrono::seconds{ConsumeTime(fuzzed_data_provider)}};

                addr_man.Connected(addr, time);

            },

            [&] {

                auto addr = ConsumeService(fuzzed_data_provider);

                auto n_services = ConsumeWeakEnum(fuzzed_data_provider, ALL_SERVICE_FLAGS);

                addr_man.SetServices(addr, n_services);

            });

    }

    const AddrMan& const_addr_man{addr_man};

    std::optional<Network> network;

    if (fuzzed_data_provider.ConsumeBool()) {

        network = fuzzed_data_provider.PickValueInArray(ALL_NETWORKS);

    }

    auto max_addresses = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 4096);

    auto max_pct = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 100);

    auto filtered = fuzzed_data_provider.ConsumeBool();

    (void)const_addr_man.GetAddr(max_addresses, max_pct, network, filtered);

    std::unordered_set<Network> nets;

    for (const auto& net : ALL_NETWORKS) {

        if (fuzzed_data_provider.ConsumeBool()) {

            nets.insert(net);

        }

    }

    (void)const_addr_man.Select(fuzzed_data_provider.ConsumeBool(), nets);

    std::optional<bool> in_new;

    if (fuzzed_data_provider.ConsumeBool()) {

        in_new = fuzzed_data_provider.ConsumeBool();

    }

    (void)const_addr_man.Size(network, in_new);

    DataStream data_stream{};

    data_stream << const_addr_man;

}

// Check that serialize followed by unserialize produces the same addrman.

FUZZ_TARGET(addrman_serdeser, .init = initialize_addrman)

{

    SeedRandomStateForTest(SeedRand::ZEROS);

    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());

    SetMockTime(ConsumeTime(fuzzed_data_provider));

    NetGroupManager netgroupman{ConsumeNetGroupManager(fuzzed_data_provider)};

    AddrManDeterministic addr_man1{netgroupman, fuzzed_data_provider, GetCheckRatio()};

    AddrManDeterministic addr_man2{netgroupman, fuzzed_data_provider, GetCheckRatio()};

    DataStream data_stream{};

    FillAddrman(addr_man1, fuzzed_data_provider);

    data_stream << addr_man1;

    data_stream >> addr_man2;

    assert(addr_man1 == addr_man2);

}