/*
 * Copyright (C) 2015-present ScyllaDB
 */

/*
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

#include "message/messaging_service.hh"
#include <seastar/core/distributed.hh>
#include "gms/failure_detector.hh"
#include "gms/gossiper.hh"
#include "gms/inet_address_serializer.hh"
#include "streaming/prepare_message.hh"
#include "gms/gossip_digest_syn.hh"
#include "gms/gossip_digest_ack.hh"
#include "gms/gossip_digest_ack2.hh"
#include "query-request.hh"
#include "query-result.hh"
#include <seastar/rpc/rpc.hh>
#include "canonical_mutation.hh"
#include "schema_mutations.hh"
#include "db/config.hh"
#include "db/view/view_update_backlog.hh"
#include "dht/i_partitioner.hh"
#include "range.hh"
#include "frozen_schema.hh"
#include "repair/repair.hh"
#include "digest_algorithm.hh"
#include "service/paxos/proposal.hh"
#include "serializer.hh"
#include "idl/consistency_level.dist.hh"
#include "idl/tracing.dist.hh"
#include "idl/result.dist.hh"
#include "idl/reconcilable_result.dist.hh"
#include "idl/ring_position.dist.hh"
#include "idl/keys.dist.hh"
#include "idl/uuid.dist.hh"
#include "idl/frozen_mutation.dist.hh"
#include "idl/frozen_schema.dist.hh"
#include "idl/streaming.dist.hh"
#include "idl/token.dist.hh"
#include "idl/gossip_digest.dist.hh"
#include "idl/read_command.dist.hh"
#include "idl/range.dist.hh"
#include "idl/partition_checksum.dist.hh"
#include "idl/query.dist.hh"
#include "idl/cache_temperature.dist.hh"
#include "idl/view.dist.hh"
#include "idl/mutation.dist.hh"
#include "idl/messaging_service.dist.hh"
#include "idl/paxos.dist.hh"
#include "idl/raft_storage.dist.hh"
#include "idl/raft.dist.hh"
#include "idl/group0.dist.hh"
#include "idl/storage_proxy.dist.hh"
#include "serializer_impl.hh"
#include "serialization_visitors.hh"
#include "message/rpc_protocol_impl.hh"
#include "idl/consistency_level.dist.impl.hh"
#include "idl/tracing.dist.impl.hh"
#include "idl/result.dist.impl.hh"
#include "idl/reconcilable_result.dist.impl.hh"
#include "idl/ring_position.dist.impl.hh"
#include "idl/keys.dist.impl.hh"
#include "idl/uuid.dist.impl.hh"
#include "idl/frozen_mutation.dist.impl.hh"
#include "idl/frozen_schema.dist.impl.hh"
#include "idl/streaming.dist.impl.hh"
#include "idl/token.dist.impl.hh"
#include "idl/gossip_digest.dist.impl.hh"
#include "idl/read_command.dist.impl.hh"
#include "idl/range.dist.impl.hh"
#include "idl/query.dist.impl.hh"
#include "idl/cache_temperature.dist.impl.hh"
#include "idl/mutation.dist.impl.hh"
#include "idl/messaging_service.dist.impl.hh"
#include "idl/paxos.dist.impl.hh"
#include "idl/raft_storage.dist.impl.hh"
#include "idl/raft.dist.impl.hh"
#include "idl/group0.dist.impl.hh"
#include "idl/view.dist.impl.hh"
#include "idl/storage_proxy.dist.impl.hh"
#include <seastar/rpc/lz4_compressor.hh>
#include <seastar/rpc/lz4_fragmented_compressor.hh>
#include <seastar/rpc/multi_algo_compressor_factory.hh>
#include "partition_range_compat.hh"
#include <boost/range/adaptor/filtered.hpp>
#include <boost/range/adaptor/indirected.hpp>
#include "frozen_mutation.hh"
#include "readers/flat_mutation_reader.hh"
#include "streaming/stream_manager.hh"
#include "streaming/stream_mutation_fragments_cmd.hh"
#include "locator/snitch_base.hh"
#include "idl/partition_checksum.dist.impl.hh"
#include "idl/forward_request.dist.hh"
#include "idl/forward_request.dist.impl.hh"

namespace netw {

static_assert(!std::is_default_constructible_v<msg_addr>);
static_assert(std::is_nothrow_copy_constructible_v<msg_addr>);
static_assert(std::is_nothrow_move_constructible_v<msg_addr>);

static logging::logger mlogger("messaging_service");
static logging::logger rpc_logger("rpc");

using inet_address = gms::inet_address;
using gossip_digest_syn = gms::gossip_digest_syn;
using gossip_digest_ack = gms::gossip_digest_ack;
using gossip_digest_ack2 = gms::gossip_digest_ack2;
using namespace std::chrono_literals;

static rpc::lz4_fragmented_compressor::factory lz4_fragmented_compressor_factory;
static rpc::lz4_compressor::factory lz4_compressor_factory;
static rpc::multi_algo_compressor_factory compressor_factory {
    &lz4_fragmented_compressor_factory,
    &lz4_compressor_factory,
};

struct messaging_service::rpc_protocol_server_wrapper : public rpc_protocol::server { using rpc_protocol::server::server; };

constexpr int32_t messaging_service::current_version;

// Count of connection types that are not associated with any tenant
const size_t PER_SHARD_CONNECTION_COUNT = 2;
// Counts per tenant connection types
const size_t PER_TENANT_CONNECTION_COUNT = 3;

bool operator==(const msg_addr& x, const msg_addr& y) noexcept {
    // Ignore cpu id for now since we do not really support shard to shard connections
    return x.addr == y.addr;
}

bool operator<(const msg_addr& x, const msg_addr& y) noexcept {
    // Ignore cpu id for now since we do not really support shard to shard connections
    if (x.addr < y.addr) {
        return true;
    } else {
        return false;
    }
}

std::ostream& operator<<(std::ostream& os, const msg_addr& x) {
    return os << x.addr << ":" << x.cpu_id;
}

size_t msg_addr::hash::operator()(const msg_addr& id) const noexcept {
    // Ignore cpu id for now since we do not really support // shard to shard connections
    return std::hash<bytes_view>()(id.addr.bytes());
}

messaging_service::shard_info::shard_info(shared_ptr<rpc_protocol_client_wrapper>&& client)
    : rpc_client(std::move(client)) {
}

rpc::stats messaging_service::shard_info::get_stats() const {
    return rpc_client->get_stats();
}

void messaging_service::foreach_client(std::function<void(const msg_addr& id, const shard_info& info)> f) const {
    for (unsigned idx = 0; idx < _clients.size(); idx ++) {
        for (auto i = _clients[idx].cbegin(); i != _clients[idx].cend(); i++) {
            f(i->first, i->second);
        }
    }
}

void messaging_service::foreach_server_connection_stats(std::function<void(const rpc::client_info&, const rpc::stats&)>&& f) const {
    for (auto&& s : _server) {
        if (s) {
            s->foreach_connection([f](const rpc_protocol::server::connection& c) {
                f(c.info(), c.get_stats());
            });
        }
    }
}

void messaging_service::increment_dropped_messages(messaging_verb verb) {
    _dropped_messages[static_cast<int32_t>(verb)]++;
}

uint64_t messaging_service::get_dropped_messages(messaging_verb verb) const {
    return _dropped_messages[static_cast<int32_t>(verb)];
}

const uint64_t* messaging_service::get_dropped_messages() const {
    return _dropped_messages;
}

int32_t messaging_service::get_raw_version(const gms::inet_address& endpoint) const {
    // FIXME: messaging service versioning
    return current_version;
}

bool messaging_service::knows_version(const gms::inet_address& endpoint) const {
    // FIXME: messaging service versioning
    return true;
}

future<> messaging_service::unregister_handler(messaging_verb verb) {
    return _rpc->unregister_handler(verb);
}

messaging_service::messaging_service(gms::inet_address ip, uint16_t port)
    : messaging_service(config{std::move(ip), port}, scheduling_config{{{{}, "$default"}}, {}, {}}, nullptr)
{}

static
rpc::resource_limits
rpc_resource_limits(size_t memory_limit) {
    rpc::resource_limits limits;
    limits.bloat_factor = 3;
    limits.basic_request_size = 1000;
    limits.max_memory = memory_limit;
    return limits;
}

future<> messaging_service::start_listen() {
    if (_credentials_builder && !_credentials) {
        return _credentials_builder->build_reloadable_server_credentials([](const std::unordered_set<sstring>& files, std::exception_ptr ep) {
            if (ep) {
                mlogger.warn("Exception loading {}: {}", files, ep);
            } else {
                mlogger.info("Reloaded {}", files);
            }
        }).then([this](shared_ptr<seastar::tls::server_credentials> creds) {
            _credentials = std::move(creds);
            do_start_listen();
        });
    }
    do_start_listen();
    return make_ready_future<>();
}

void messaging_service::do_start_listen() {
    bool listen_to_bc = _cfg.listen_on_broadcast_address && _cfg.ip != utils::fb_utilities::get_broadcast_address();
    rpc::server_options so;
    if (_cfg.compress != compress_what::none) {
        so.compressor_factory = &compressor_factory;
    }
    so.load_balancing_algorithm = server_socket::load_balancing_algorithm::port;

    // FIXME: we don't set so.tcp_nodelay, because we can't tell at this point whether the connection will come from a
    //        local or remote datacenter, and whether or not the connection will be used for gossip. We can fix
    //        the first by wrapping its server_socket, but not the second.
    auto limits = rpc_resource_limits(_cfg.rpc_memory_limit);
    limits.isolate_connection = [this] (sstring isolation_cookie) {
        rpc::isolation_config cfg;
        cfg.sched_group = scheduling_group_for_isolation_cookie(isolation_cookie);
        return cfg;
    };
    if (!_server[0] && _cfg.encrypt != encrypt_what::all && _cfg.port) {
        auto listen = [&] (const gms::inet_address& a, rpc::streaming_domain_type sdomain) {
            so.streaming_domain = sdomain;
            so.filter_connection = {};
            switch (_cfg.encrypt) {
                default:
                case encrypt_what::none:
                    break;
                case encrypt_what::dc:
                    so.filter_connection = [](const seastar::socket_address& addr) {
                        auto& snitch = locator::i_endpoint_snitch::get_local_snitch_ptr();
                        return snitch->get_datacenter(addr) == snitch->get_datacenter(utils::fb_utilities::get_broadcast_address());
                    };
                    break;
                case encrypt_what::rack:
                    so.filter_connection = [](const seastar::socket_address& addr) {
                        auto& snitch = locator::i_endpoint_snitch::get_local_snitch_ptr();
                        return snitch->get_datacenter(addr) == snitch->get_datacenter(utils::fb_utilities::get_broadcast_address())
                            && snitch->get_rack(addr) == snitch->get_rack(utils::fb_utilities::get_broadcast_address())
                            ;
                    };
                    break;
            }
            auto addr = socket_address{a, _cfg.port};
            return std::unique_ptr<rpc_protocol_server_wrapper>(new rpc_protocol_server_wrapper(_rpc->protocol(),
                    so, addr, limits));
        };
        _server[0] = listen(_cfg.ip, rpc::streaming_domain_type(0x55AA));
        if (listen_to_bc) {
            _server[1] = listen(utils::fb_utilities::get_broadcast_address(), rpc::streaming_domain_type(0x66BB));
        }
    }
    
    if (!_server_tls[0] && _cfg.ssl_port) {
        auto listen = [&] (const gms::inet_address& a, rpc::streaming_domain_type sdomain) {
            so.filter_connection = {};
            so.streaming_domain = sdomain;
            return std::unique_ptr<rpc_protocol_server_wrapper>(
                    [this, &so, &a, limits] () -> std::unique_ptr<rpc_protocol_server_wrapper>{
                if (_cfg.encrypt == encrypt_what::none) {
                    return nullptr;
                }
                if (!_credentials) {
                    throw std::invalid_argument("No certificates specified for encrypted service");
                }
                listen_options lo;
                lo.reuse_address = true;
                lo.lba =  server_socket::load_balancing_algorithm::port;
                auto addr = socket_address{a, _cfg.ssl_port};
                return std::make_unique<rpc_protocol_server_wrapper>(_rpc->protocol(),
                        so, seastar::tls::listen(_credentials, addr, lo), limits);
            }());
        };
        _server_tls[0] = listen(_cfg.ip, rpc::streaming_domain_type(0x77CC));
        if (listen_to_bc) {
            _server_tls[1] = listen(utils::fb_utilities::get_broadcast_address(), rpc::streaming_domain_type(0x88DD));
        }
    }
    // Do this on just cpu 0, to avoid duplicate logs.
    if (this_shard_id() == 0) {
        if (_server_tls[0]) {
            mlogger.info("Starting Encrypted Messaging Service on SSL port {}", _cfg.ssl_port);
        }
        if (_server_tls[1]) {
            mlogger.info("Starting Encrypted Messaging Service on SSL broadcast address {} port {}", utils::fb_utilities::get_broadcast_address(), _cfg.ssl_port);
        }
        if (_server[0]) {
            mlogger.info("Starting Messaging Service on port {}", _cfg.port);
        }
        if (_server[1]) {
            mlogger.info("Starting Messaging Service on broadcast address {} port {}", utils::fb_utilities::get_broadcast_address(), _cfg.port);
        }
    }
}

messaging_service::messaging_service(config cfg, scheduling_config scfg, std::shared_ptr<seastar::tls::credentials_builder> credentials)
    : _cfg(std::move(cfg))
    , _rpc(new rpc_protocol_wrapper(serializer { }))
    , _credentials_builder(credentials ? std::make_unique<seastar::tls::credentials_builder>(*credentials) : nullptr)
    , _clients(PER_SHARD_CONNECTION_COUNT + scfg.statement_tenants.size() * PER_TENANT_CONNECTION_COUNT)
    , _scheduling_config(scfg)
    , _scheduling_info_for_connection_index(initial_scheduling_info())
{
    _rpc->set_logger(&rpc_logger);

    // this initialization should be done before any handler registration
    // this is because register_handler calls to: scheduling_group_for_verb
    // which in turn relies on _connection_index_for_tenant to be initialized.
    _connection_index_for_tenant.reserve(_scheduling_config.statement_tenants.size());
    for (unsigned i = 0; i <  _scheduling_config.statement_tenants.size(); ++i) {
        _connection_index_for_tenant.push_back({_scheduling_config.statement_tenants[i].sched_group, i});
    }

    register_handler(this, messaging_verb::CLIENT_ID, [] (rpc::client_info& ci, gms::inet_address broadcast_address, uint32_t src_cpu_id, rpc::optional<uint64_t> max_result_size) {
        ci.attach_auxiliary("baddr", broadcast_address);
        ci.attach_auxiliary("src_cpu_id", src_cpu_id);
        ci.attach_auxiliary("max_result_size", max_result_size.value_or(query::result_memory_limiter::maximum_result_size));
        return rpc::no_wait;
    });
}

msg_addr messaging_service::get_source(const rpc::client_info& cinfo) {
    return msg_addr{
        cinfo.retrieve_auxiliary<gms::inet_address>("baddr"),
        cinfo.retrieve_auxiliary<uint32_t>("src_cpu_id")
    };
}

messaging_service::~messaging_service() = default;

uint16_t messaging_service::port() {
    return _cfg.port;
}

gms::inet_address messaging_service::listen_address() {
    return _cfg.ip;
}

static future<> stop_servers(std::array<std::unique_ptr<messaging_service::rpc_protocol_server_wrapper>, 2>& servers) {
    return parallel_for_each(
            servers | boost::adaptors::filtered([] (auto& ptr) { return bool(ptr); }) | boost::adaptors::indirected,
            std::mem_fn(&messaging_service::rpc_protocol_server_wrapper::stop));
}

future<> messaging_service::stop_tls_server() {
    mlogger.info("Stopping tls server");
    return stop_servers(_server_tls).then( [] {
        mlogger.info("Stopping tls server - Done");
    });
}

future<> messaging_service::stop_nontls_server() {
    mlogger.info("Stopping nontls server");
    return stop_servers(_server).then([] {
        mlogger.info("Stopping nontls server - Done");
    });
}

future<> messaging_service::stop_client() {
    return parallel_for_each(_clients, [] (auto& m) {
        return parallel_for_each(m, [] (std::pair<const msg_addr, shard_info>& c) {
            mlogger.info("Stopping client for address: {}", c.first);
            return c.second.rpc_client->stop().then([addr = c.first] {
                mlogger.info("Stopping client for address: {} - Done", addr);
            });
        });
    });
}

future<> messaging_service::shutdown() {
    _shutting_down = true;
    return when_all(stop_nontls_server(), stop_tls_server(), stop_client()).discard_result();
}

future<> messaging_service::stop() {
    return unregister_handler(messaging_verb::CLIENT_ID).then([this] {
        if (_rpc->has_handlers()) {
            mlogger.error("RPC server still has handlers registered");
            for (auto verb = messaging_verb::MUTATION; verb < messaging_verb::LAST;
                    verb = messaging_verb(int(verb) + 1)) {
                if (_rpc->has_handler(verb)) {
                    mlogger.error(" - {}", static_cast<int>(verb));
                }
            }

            std::abort();
        }

        return make_ready_future<>();
    });
}

rpc::no_wait_type messaging_service::no_wait() {
    return rpc::no_wait;
}


static constexpr unsigned do_get_rpc_client_idx(messaging_verb verb) {
    // *_CONNECTION_COUNT constants needs to be updated after allocating a new index.
    switch (verb) {
    // GET_SCHEMA_VERSION is sent from read/mutate verbs so should be
    // sent on a different connection to avoid potential deadlocks
    // as well as reduce latency as there are potentially many requests
    // blocked on schema version request.
    case messaging_verb::GOSSIP_DIGEST_SYN:
    case messaging_verb::GOSSIP_DIGEST_ACK:
    case messaging_verb::GOSSIP_DIGEST_ACK2:
    case messaging_verb::GOSSIP_SHUTDOWN:
    case messaging_verb::GOSSIP_ECHO:
    case messaging_verb::GOSSIP_GET_ENDPOINT_STATES:
    case messaging_verb::GET_SCHEMA_VERSION:
    // Raft peer exchange is mainly running at boot, but still
    // should not be blocked by any data requests.
    case messaging_verb::GROUP0_PEER_EXCHANGE:
    case messaging_verb::GROUP0_MODIFY_CONFIG:
        return 0;
    case messaging_verb::PREPARE_MESSAGE:
    case messaging_verb::PREPARE_DONE_MESSAGE:
    case messaging_verb::UNUSED__STREAM_MUTATION:
    case messaging_verb::STREAM_MUTATION_DONE:
    case messaging_verb::COMPLETE_MESSAGE:
    case messaging_verb::REPLICATION_FINISHED:
    case messaging_verb::UNUSED__REPAIR_CHECKSUM_RANGE:
    case messaging_verb::STREAM_MUTATION_FRAGMENTS:
    case messaging_verb::REPAIR_ROW_LEVEL_START:
    case messaging_verb::REPAIR_ROW_LEVEL_STOP:
    case messaging_verb::REPAIR_GET_FULL_ROW_HASHES:
    case messaging_verb::REPAIR_GET_COMBINED_ROW_HASH:
    case messaging_verb::REPAIR_GET_SYNC_BOUNDARY:
    case messaging_verb::REPAIR_GET_ROW_DIFF:
    case messaging_verb::REPAIR_PUT_ROW_DIFF:
    case messaging_verb::REPAIR_GET_ESTIMATED_PARTITIONS:
    case messaging_verb::REPAIR_SET_ESTIMATED_PARTITIONS:
    case messaging_verb::REPAIR_GET_DIFF_ALGORITHMS:
    case messaging_verb::REPAIR_GET_ROW_DIFF_WITH_RPC_STREAM:
    case messaging_verb::REPAIR_PUT_ROW_DIFF_WITH_RPC_STREAM:
    case messaging_verb::REPAIR_GET_FULL_ROW_HASHES_WITH_RPC_STREAM:
    case messaging_verb::REPAIR_UPDATE_SYSTEM_TABLE:
    case messaging_verb::REPAIR_FLUSH_HINTS_BATCHLOG:
    case messaging_verb::NODE_OPS_CMD:
    case messaging_verb::HINT_MUTATION:
        return 1;
    case messaging_verb::CLIENT_ID:
    case messaging_verb::MUTATION:
    case messaging_verb::READ_DATA:
    case messaging_verb::READ_MUTATION_DATA:
    case messaging_verb::READ_DIGEST:
    case messaging_verb::DEFINITIONS_UPDATE:
    case messaging_verb::TRUNCATE:
    case messaging_verb::MIGRATION_REQUEST:
    case messaging_verb::SCHEMA_CHECK:
    case messaging_verb::COUNTER_MUTATION:
    // Use the same RPC client for light weight transaction
    // protocol steps as for standard mutations and read requests.
    case messaging_verb::PAXOS_PREPARE:
    case messaging_verb::PAXOS_ACCEPT:
    case messaging_verb::PAXOS_LEARN:
    case messaging_verb::PAXOS_PRUNE:
    case messaging_verb::RAFT_SEND_SNAPSHOT:
    case messaging_verb::RAFT_APPEND_ENTRIES:
    case messaging_verb::RAFT_APPEND_ENTRIES_REPLY:
    case messaging_verb::RAFT_VOTE_REQUEST:
    case messaging_verb::RAFT_VOTE_REPLY:
    case messaging_verb::RAFT_TIMEOUT_NOW:
    case messaging_verb::RAFT_READ_QUORUM:
    case messaging_verb::RAFT_READ_QUORUM_REPLY:
    case messaging_verb::RAFT_EXECUTE_READ_BARRIER_ON_LEADER:
    case messaging_verb::RAFT_ADD_ENTRY:
    case messaging_verb::RAFT_MODIFY_CONFIG:
        return 2;
    case messaging_verb::MUTATION_DONE:
    case messaging_verb::MUTATION_FAILED:
        return 3;
    case messaging_verb::FORWARD_REQUEST:
        return 4;
    case messaging_verb::LAST:
        return -1; // should never happen
    }
}

static constexpr std::array<uint8_t, static_cast<size_t>(messaging_verb::LAST)> make_rpc_client_idx_table() {
    std::array<uint8_t, static_cast<size_t>(messaging_verb::LAST)> tab{};
    for (size_t i = 0; i < tab.size(); ++i) {
        tab[i] = do_get_rpc_client_idx(messaging_verb(i));

        // This assert guards against adding new connection types without
        // updating *_CONNECTION_COUNT constants.
        assert(tab[i] < PER_TENANT_CONNECTION_COUNT + PER_SHARD_CONNECTION_COUNT);
    }
    return tab;
}

static std::array<uint8_t, static_cast<size_t>(messaging_verb::LAST)> s_rpc_client_idx_table = make_rpc_client_idx_table();

unsigned
messaging_service::get_rpc_client_idx(messaging_verb verb) const {
    auto idx = s_rpc_client_idx_table[static_cast<size_t>(verb)];

    if (idx < PER_SHARD_CONNECTION_COUNT) {
        return idx;
    }

    // A statement or statement-ack verb
    const auto curr_sched_group = current_scheduling_group();
    for (unsigned i = 0; i < _connection_index_for_tenant.size(); ++i) {
        if (_connection_index_for_tenant[i].sched_group == curr_sched_group) {
            // i == 0: the default tenant maps to the default client indexes beloning to the interval
            // [PER_SHARD_CONNECTION_COUNT, PER_SHARD_CONNECTION_COUNT + PER_TENANT_CONNECTION_COUNT).
            idx += i * PER_TENANT_CONNECTION_COUNT;
            break;
        }
    }
    return idx;
}

std::vector<messaging_service::scheduling_info_for_connection_index>
messaging_service::initial_scheduling_info() const {
    if (_scheduling_config.statement_tenants.empty()) {
        throw std::runtime_error("messaging_service::initial_scheduling_info(): must have at least one tenant configured");
    }
    auto sched_infos = std::vector<scheduling_info_for_connection_index>({
        { _scheduling_config.gossip, "gossip" },
        { _scheduling_config.streaming, "streaming", },
    });

    sched_infos.reserve(sched_infos.size() +
        _scheduling_config.statement_tenants.size() * PER_TENANT_CONNECTION_COUNT);
    for (const auto& tenant : _scheduling_config.statement_tenants) {
        sched_infos.push_back({ tenant.sched_group, "statement:" + tenant.name });
        sched_infos.push_back({ tenant.sched_group, "statement-ack:" + tenant.name });
        sched_infos.push_back({ tenant.sched_group, "forward:" + tenant.name });
    }

    assert(sched_infos.size() == PER_SHARD_CONNECTION_COUNT +
        _scheduling_config.statement_tenants.size() * PER_TENANT_CONNECTION_COUNT);
    return sched_infos;
};

scheduling_group
messaging_service::scheduling_group_for_verb(messaging_verb verb) const {
    // We are not using get_rpc_client_idx() because it figures out the client
    // index based on the current scheduling group, which is relevant when
    // selecting the right client for sending a message, but is not relevant
    // when registering handlers.
    const auto idx = s_rpc_client_idx_table[static_cast<size_t>(verb)];
    return _scheduling_info_for_connection_index[idx].sched_group;
}

scheduling_group
messaging_service::scheduling_group_for_isolation_cookie(const sstring& isolation_cookie) const {
    // Once per connection, so a loop is fine.
    for (auto&& info : _scheduling_info_for_connection_index) {
        if (info.isolation_cookie == isolation_cookie) {
            return info.sched_group;
        }
    }
    // Client is using a new connection class that the server doesn't recognize yet.
    // Assume it's important, after server upgrade we'll recognize it.
    return default_scheduling_group();
}


/**
 * Get an IP for a given endpoint to connect to
 *
 * @param ep endpoint to check
 *
 * @return preferred IP (local) for the given endpoint if exists and if the
 *         given endpoint resides in the same data center with the current Node.
 *         Otherwise 'ep' itself is returned.
 */
gms::inet_address messaging_service::get_preferred_ip(gms::inet_address ep) {
    auto it = _preferred_ip_cache.find(ep);

    if (it != _preferred_ip_cache.end()) {
        auto& snitch_ptr = locator::i_endpoint_snitch::get_local_snitch_ptr();
        auto my_addr = utils::fb_utilities::get_broadcast_address();

        if (snitch_ptr->get_datacenter(ep) == snitch_ptr->get_datacenter(my_addr)) {
            return it->second;
        }
    }

    // If cache doesn't have an entry for this endpoint - return endpoint itself
    return ep;
}

void messaging_service::init_local_preferred_ip_cache(const std::unordered_map<gms::inet_address, gms::inet_address>& ips_cache) {
    _preferred_ip_cache = ips_cache;
    _preferred_to_endpoint.clear();
    //
    // Reset the connections to the endpoints that have entries in
    // _preferred_ip_cache so that they reopen with the preferred IPs we've
    // just read.
    //
    for (auto& p : _preferred_ip_cache) {
        this->remove_rpc_client(msg_addr(p.first));
        _preferred_to_endpoint[p.second] = p.first;
    }
}

void messaging_service::cache_preferred_ip(gms::inet_address ep, gms::inet_address ip) {
    _preferred_ip_cache[ep] = ip;
    _preferred_to_endpoint[ip] = ep;
}

gms::inet_address messaging_service::get_public_endpoint_for(const gms::inet_address& ip) const {
    auto i = _preferred_to_endpoint.find(ip);
    return i != _preferred_to_endpoint.end() ? i->second : ip;
}

shared_ptr<messaging_service::rpc_protocol_client_wrapper> messaging_service::get_rpc_client(messaging_verb verb, msg_addr id) {
    assert(!_shutting_down);
    auto idx = get_rpc_client_idx(verb);
    auto it = _clients[idx].find(id);

    if (it != _clients[idx].end()) {
        auto c = it->second.rpc_client;
        if (!c->error()) {
            return c;
        }
        remove_error_rpc_client(verb, id);
    }

    auto addr = get_preferred_ip(id.addr);
    auto broadcast_address = utils::fb_utilities::get_broadcast_address();
    bool listen_to_bc = _cfg.listen_on_broadcast_address && _cfg.ip != broadcast_address;
    auto laddr = socket_address(listen_to_bc ? broadcast_address : _cfg.ip, 0);

    auto must_encrypt = [&] {
        if (_cfg.encrypt == encrypt_what::none) {
            return false;
        }
        if (_cfg.encrypt == encrypt_what::all) {
            return true;
        }

        // if we have dc/rack encryption but this is gossip, we should
        // use tls anyway, to avoid having mismatched ideas on which 
        // group we/client are in. 
        if (verb >= messaging_verb::GOSSIP_DIGEST_SYN && verb <= messaging_verb::GOSSIP_SHUTDOWN) {
            return true;
        }

        auto& snitch_ptr = locator::i_endpoint_snitch::get_local_snitch_ptr();

        // either rack/dc need to be in same dc to use non-tls
        auto my_dc = snitch_ptr->get_datacenter(broadcast_address);
        if (snitch_ptr->get_datacenter(addr) != my_dc) {
            return true;
        }
        // #9653 - if our idea of dc for bind address differs from our official endpoint address,
        // we cannot trust downgrading. We need to ensure either (local) bind address is same as
        // broadcast or that the dc info we get for it is the same.
        if (broadcast_address != laddr && snitch_ptr->get_datacenter(laddr) != my_dc) {
            return true;
        }
        // if cross-rack tls, check rack.
        if (_cfg.encrypt == encrypt_what::dc) {
            return false;
        }
        auto my_rack = snitch_ptr->get_rack(broadcast_address);
        if (snitch_ptr->get_rack(addr) != my_rack) {
            return true;
        }
        // See above: We need to ensure either (local) bind address is same as
        // broadcast or that the rack info we get for it is the same.
        return broadcast_address != laddr && snitch_ptr->get_rack(laddr) != my_rack;
    }();

    auto must_compress = [&id, this] {
        if (_cfg.compress == compress_what::none) {
            return false;
        }

        if (_cfg.compress == compress_what::dc) {
            auto& snitch_ptr = locator::i_endpoint_snitch::get_local_snitch_ptr();
            return snitch_ptr->get_datacenter(id.addr)
                            != snitch_ptr->get_datacenter(utils::fb_utilities::get_broadcast_address());
        }

        return true;
    }();

    auto must_tcp_nodelay = [&] {
        if (idx == 1) {
            return true; // gossip
        }
        if (_cfg.tcp_nodelay == tcp_nodelay_what::local) {
            auto& snitch_ptr = locator::i_endpoint_snitch::get_local_snitch_ptr();
            return snitch_ptr->get_datacenter(id.addr)
                            == snitch_ptr->get_datacenter(utils::fb_utilities::get_broadcast_address());
        }
        return true;
    }();

    auto remote_addr = socket_address(addr, must_encrypt ? _cfg.ssl_port : _cfg.port);

    rpc::client_options opts;
    // send keepalive messages each minute if connection is idle, drop connection after 10 failures
    opts.keepalive = std::optional<net::tcp_keepalive_params>({60s, 60s, 10});
    if (must_compress) {
        opts.compressor_factory = &compressor_factory;
    }
    opts.tcp_nodelay = must_tcp_nodelay;
    opts.reuseaddr = true;
    // We send cookies only for non-default statement tenant clients.
    if (idx >= PER_SHARD_CONNECTION_COUNT + PER_TENANT_CONNECTION_COUNT) {
        opts.isolation_cookie = _scheduling_info_for_connection_index[idx].isolation_cookie;
    }

    auto client = must_encrypt ?
                    ::make_shared<rpc_protocol_client_wrapper>(_rpc->protocol(), std::move(opts),
                                    remote_addr, laddr, _credentials) :
                    ::make_shared<rpc_protocol_client_wrapper>(_rpc->protocol(), std::move(opts),
                                    remote_addr, laddr);

    auto res = _clients[idx].emplace(id, shard_info(std::move(client)));
    assert(res.second);
    it = res.first;
    uint32_t src_cpu_id = this_shard_id();
    // No reply is received, nothing to wait for.
    (void)_rpc->make_client<rpc::no_wait_type(gms::inet_address, uint32_t, uint64_t)>(messaging_verb::CLIENT_ID)(*it->second.rpc_client, utils::fb_utilities::get_broadcast_address(), src_cpu_id,
                                                                                                           query::result_memory_limiter::maximum_result_size).handle_exception([ms = shared_from_this(), remote_addr, verb] (std::exception_ptr ep) {
        mlogger.debug("Failed to send client id to {} for verb {}: {}", remote_addr, std::underlying_type_t<messaging_verb>(verb), ep);
    });
    return it->second.rpc_client;
}

bool messaging_service::remove_rpc_client_one(clients_map& clients, msg_addr id, bool dead_only) {
    if (_shutting_down) {
        // if messaging service is in a processed of been stopped no need to
        // stop and remove connection here since they are being stopped already
        // and we'll just interfere
        return false;
    }

    bool found = false;
    auto it = clients.find(id);
    if (it != clients.end() && (!dead_only || it->second.rpc_client->error())) {
        auto client = std::move(it->second.rpc_client);
        clients.erase(it);
        //
        // Explicitly call rpc_protocol_client_wrapper::stop() for the erased
        // item and hold the messaging_service shared pointer till it's over.
        // This will make sure messaging_service::stop() blocks until
        // client->stop() is over.
        //
        (void)client->stop().finally([id, client, ms = shared_from_this()] {
            mlogger.debug("dropped connection to {}", id.addr);
        }).discard_result();
        found = true;
    }
    return found;
}

void messaging_service::remove_error_rpc_client(messaging_verb verb, msg_addr id) {
    if (remove_rpc_client_one(_clients[get_rpc_client_idx(verb)], id, true)) {
        _connection_dropped(id.addr);
    }
}

void messaging_service::remove_rpc_client(msg_addr id) {
    for (auto& c : _clients) {
        remove_rpc_client_one(c, id, false);
    }
}

std::unique_ptr<messaging_service::rpc_protocol_wrapper>& messaging_service::rpc() {
    return _rpc;
}

rpc::sink<int32_t> messaging_service::make_sink_for_stream_mutation_fragments(rpc::source<frozen_mutation_fragment, rpc::optional<streaming::stream_mutation_fragments_cmd>>& source) {
    return source.make_sink<netw::serializer, int32_t>();
}

future<std::tuple<rpc::sink<frozen_mutation_fragment, streaming::stream_mutation_fragments_cmd>, rpc::source<int32_t>>>
messaging_service::make_sink_and_source_for_stream_mutation_fragments(utils::UUID schema_id, utils::UUID plan_id, utils::UUID cf_id, uint64_t estimated_partitions, streaming::stream_reason reason, msg_addr id) {
    using value_type = std::tuple<rpc::sink<frozen_mutation_fragment, streaming::stream_mutation_fragments_cmd>, rpc::source<int32_t>>;
    if (is_shutting_down()) {
        return make_exception_future<value_type>(rpc::closed_error());
    }
    auto rpc_client = get_rpc_client(messaging_verb::STREAM_MUTATION_FRAGMENTS, id);
    return rpc_client->make_stream_sink<netw::serializer, frozen_mutation_fragment, streaming::stream_mutation_fragments_cmd>().then([this, plan_id, schema_id, cf_id, estimated_partitions, reason, rpc_client] (rpc::sink<frozen_mutation_fragment, streaming::stream_mutation_fragments_cmd> sink) mutable {
        auto rpc_handler = rpc()->make_client<rpc::source<int32_t> (utils::UUID, utils::UUID, utils::UUID, uint64_t, streaming::stream_reason, rpc::sink<frozen_mutation_fragment, streaming::stream_mutation_fragments_cmd>)>(messaging_verb::STREAM_MUTATION_FRAGMENTS);
        return rpc_handler(*rpc_client , plan_id, schema_id, cf_id, estimated_partitions, reason, sink).then_wrapped([sink, rpc_client] (future<rpc::source<int32_t>> source) mutable {
            return (source.failed() ? sink.close() : make_ready_future<>()).then([sink = std::move(sink), source = std::move(source)] () mutable {
                return make_ready_future<value_type>(value_type(std::move(sink), source.get0()));
            });
        });
    });
}

void messaging_service::register_stream_mutation_fragments(std::function<future<rpc::sink<int32_t>> (const rpc::client_info& cinfo, UUID plan_id, UUID schema_id, UUID cf_id, uint64_t estimated_partitions, rpc::optional<streaming::stream_reason>, rpc::source<frozen_mutation_fragment, rpc::optional<streaming::stream_mutation_fragments_cmd>> source)>&& func) {
    register_handler(this, messaging_verb::STREAM_MUTATION_FRAGMENTS, std::move(func));
}

future<> messaging_service::unregister_stream_mutation_fragments() {
    return unregister_handler(messaging_verb::STREAM_MUTATION_FRAGMENTS);
}

template<class SinkType, class SourceType>
future<std::tuple<rpc::sink<SinkType>, rpc::source<SourceType>>>
do_make_sink_source(messaging_verb verb, uint32_t repair_meta_id, shared_ptr<messaging_service::rpc_protocol_client_wrapper> rpc_client, std::unique_ptr<messaging_service::rpc_protocol_wrapper>& rpc) {
    using value_type = std::tuple<rpc::sink<SinkType>, rpc::source<SourceType>>;
    return rpc_client->make_stream_sink<netw::serializer, SinkType>().then([&rpc, verb, repair_meta_id, rpc_client] (rpc::sink<SinkType> sink) mutable {
        auto rpc_handler = rpc->make_client<rpc::source<SourceType> (uint32_t, rpc::sink<SinkType>)>(verb);
        return rpc_handler(*rpc_client, repair_meta_id, sink).then_wrapped([sink, rpc_client] (future<rpc::source<SourceType>> source) mutable {
            return (source.failed() ? sink.close() : make_ready_future<>()).then([sink = std::move(sink), source = std::move(source)] () mutable {
                return make_ready_future<value_type>(value_type(std::move(sink), std::move(source.get0())));
            });
        });
    });
}

// Wrapper for REPAIR_GET_ROW_DIFF_WITH_RPC_STREAM
future<std::tuple<rpc::sink<repair_hash_with_cmd>, rpc::source<repair_row_on_wire_with_cmd>>>
messaging_service::make_sink_and_source_for_repair_get_row_diff_with_rpc_stream(uint32_t repair_meta_id, msg_addr id) {
    auto verb = messaging_verb::REPAIR_GET_ROW_DIFF_WITH_RPC_STREAM;
    if (is_shutting_down()) {
        return make_exception_future<std::tuple<rpc::sink<repair_hash_with_cmd>, rpc::source<repair_row_on_wire_with_cmd>>>(rpc::closed_error());
    }
    auto rpc_client = get_rpc_client(verb, id);
    return do_make_sink_source<repair_hash_with_cmd, repair_row_on_wire_with_cmd>(verb, repair_meta_id, std::move(rpc_client), rpc());
}

rpc::sink<repair_row_on_wire_with_cmd> messaging_service::make_sink_for_repair_get_row_diff_with_rpc_stream(rpc::source<repair_hash_with_cmd>& source) {
    return source.make_sink<netw::serializer, repair_row_on_wire_with_cmd>();
}

void messaging_service::register_repair_get_row_diff_with_rpc_stream(std::function<future<rpc::sink<repair_row_on_wire_with_cmd>> (const rpc::client_info& cinfo, uint32_t repair_meta_id, rpc::source<repair_hash_with_cmd> source)>&& func) {
    register_handler(this, messaging_verb::REPAIR_GET_ROW_DIFF_WITH_RPC_STREAM, std::move(func));
}
future<> messaging_service::unregister_repair_get_row_diff_with_rpc_stream() {
    return unregister_handler(messaging_verb::REPAIR_GET_ROW_DIFF_WITH_RPC_STREAM);
}

// Wrapper for REPAIR_PUT_ROW_DIFF_WITH_RPC_STREAM
future<std::tuple<rpc::sink<repair_row_on_wire_with_cmd>, rpc::source<repair_stream_cmd>>>
messaging_service::make_sink_and_source_for_repair_put_row_diff_with_rpc_stream(uint32_t repair_meta_id, msg_addr id) {
    auto verb = messaging_verb::REPAIR_PUT_ROW_DIFF_WITH_RPC_STREAM;
    if (is_shutting_down()) {
        return make_exception_future<std::tuple<rpc::sink<repair_row_on_wire_with_cmd>, rpc::source<repair_stream_cmd>>>(rpc::closed_error());
    }
    auto rpc_client = get_rpc_client(verb, id);
    return do_make_sink_source<repair_row_on_wire_with_cmd, repair_stream_cmd>(verb, repair_meta_id, std::move(rpc_client), rpc());
}

rpc::sink<repair_stream_cmd> messaging_service::make_sink_for_repair_put_row_diff_with_rpc_stream(rpc::source<repair_row_on_wire_with_cmd>& source) {
    return source.make_sink<netw::serializer, repair_stream_cmd>();
}

void messaging_service::register_repair_put_row_diff_with_rpc_stream(std::function<future<rpc::sink<repair_stream_cmd>> (const rpc::client_info& cinfo, uint32_t repair_meta_id, rpc::source<repair_row_on_wire_with_cmd> source)>&& func) {
    register_handler(this, messaging_verb::REPAIR_PUT_ROW_DIFF_WITH_RPC_STREAM, std::move(func));
}
future<> messaging_service::unregister_repair_put_row_diff_with_rpc_stream() {
    return unregister_handler(messaging_verb::REPAIR_PUT_ROW_DIFF_WITH_RPC_STREAM);
}

// Wrapper for REPAIR_GET_FULL_ROW_HASHES_WITH_RPC_STREAM
future<std::tuple<rpc::sink<repair_stream_cmd>, rpc::source<repair_hash_with_cmd>>>
messaging_service::make_sink_and_source_for_repair_get_full_row_hashes_with_rpc_stream(uint32_t repair_meta_id, msg_addr id) {
    auto verb = messaging_verb::REPAIR_GET_FULL_ROW_HASHES_WITH_RPC_STREAM;
    if (is_shutting_down()) {
        return make_exception_future<std::tuple<rpc::sink<repair_stream_cmd>, rpc::source<repair_hash_with_cmd>>>(rpc::closed_error());
    }
    auto rpc_client = get_rpc_client(verb, id);
    return do_make_sink_source<repair_stream_cmd, repair_hash_with_cmd>(verb, repair_meta_id, std::move(rpc_client), rpc());
}

rpc::sink<repair_hash_with_cmd> messaging_service::make_sink_for_repair_get_full_row_hashes_with_rpc_stream(rpc::source<repair_stream_cmd>& source) {
    return source.make_sink<netw::serializer, repair_hash_with_cmd>();
}

void messaging_service::register_repair_get_full_row_hashes_with_rpc_stream(std::function<future<rpc::sink<repair_hash_with_cmd>> (const rpc::client_info& cinfo, uint32_t repair_meta_id, rpc::source<repair_stream_cmd> source)>&& func) {
    register_handler(this, messaging_verb::REPAIR_GET_FULL_ROW_HASHES_WITH_RPC_STREAM, std::move(func));
}
future<> messaging_service::unregister_repair_get_full_row_hashes_with_rpc_stream() {
    return unregister_handler(messaging_verb::REPAIR_GET_FULL_ROW_HASHES_WITH_RPC_STREAM);
}

// Wrappers for verbs

// PREPARE_MESSAGE
void messaging_service::register_prepare_message(std::function<future<streaming::prepare_message> (const rpc::client_info& cinfo,
        streaming::prepare_message msg, UUID plan_id, sstring description, rpc::optional<streaming::stream_reason> reason)>&& func) {
    register_handler(this, messaging_verb::PREPARE_MESSAGE, std::move(func));
}
future<streaming::prepare_message> messaging_service::send_prepare_message(msg_addr id, streaming::prepare_message msg, UUID plan_id,
        sstring description, streaming::stream_reason reason) {
    return send_message<streaming::prepare_message>(this, messaging_verb::PREPARE_MESSAGE, id,
        std::move(msg), plan_id, std::move(description), reason);
}
future<> messaging_service::unregister_prepare_message() {
    return unregister_handler(messaging_verb::PREPARE_MESSAGE);
}

// PREPARE_DONE_MESSAGE
void messaging_service::register_prepare_done_message(std::function<future<> (const rpc::client_info& cinfo, UUID plan_id, unsigned dst_cpu_id)>&& func) {
    register_handler(this, messaging_verb::PREPARE_DONE_MESSAGE, std::move(func));
}
future<> messaging_service::send_prepare_done_message(msg_addr id, UUID plan_id, unsigned dst_cpu_id) {
    return send_message<void>(this, messaging_verb::PREPARE_DONE_MESSAGE, id,
        plan_id, dst_cpu_id);
}
future<> messaging_service::unregister_prepare_done_message() {
    return unregister_handler(messaging_verb::PREPARE_DONE_MESSAGE);
}

// STREAM_MUTATION_DONE
void messaging_service::register_stream_mutation_done(std::function<future<> (const rpc::client_info& cinfo,
        UUID plan_id, dht::token_range_vector ranges, UUID cf_id, unsigned dst_cpu_id)>&& func) {
    register_handler(this, messaging_verb::STREAM_MUTATION_DONE,
            [func = std::move(func)] (const rpc::client_info& cinfo,
                    UUID plan_id, std::vector<wrapping_range<dht::token>> ranges,
                    UUID cf_id, unsigned dst_cpu_id) mutable {
        return func(cinfo, plan_id, ::compat::unwrap(std::move(ranges)), cf_id, dst_cpu_id);
    });
}
future<> messaging_service::send_stream_mutation_done(msg_addr id, UUID plan_id, dht::token_range_vector ranges, UUID cf_id, unsigned dst_cpu_id) {
    return send_message<void>(this, messaging_verb::STREAM_MUTATION_DONE, id,
        plan_id, std::move(ranges), cf_id, dst_cpu_id);
}
future<> messaging_service::unregister_stream_mutation_done() {
    return unregister_handler(messaging_verb::STREAM_MUTATION_DONE);
}

// COMPLETE_MESSAGE
void messaging_service::register_complete_message(std::function<future<> (const rpc::client_info& cinfo, UUID plan_id, unsigned dst_cpu_id, rpc::optional<bool> failed)>&& func) {
    register_handler(this, messaging_verb::COMPLETE_MESSAGE, std::move(func));
}
future<> messaging_service::send_complete_message(msg_addr id, UUID plan_id, unsigned dst_cpu_id, bool failed) {
    return send_message<void>(this, messaging_verb::COMPLETE_MESSAGE, id,
        plan_id, dst_cpu_id, failed);
}
future<> messaging_service::unregister_complete_message() {
    return unregister_handler(messaging_verb::COMPLETE_MESSAGE);
}

void messaging_service::register_gossip_echo(std::function<future<> (const rpc::client_info& cinfo, rpc::optional<int64_t> generation_number)>&& func) {
    register_handler(this, messaging_verb::GOSSIP_ECHO, std::move(func));
}
future<> messaging_service::unregister_gossip_echo() {
    return unregister_handler(netw::messaging_verb::GOSSIP_ECHO);
}
future<> messaging_service::send_gossip_echo(msg_addr id, int64_t generation_number, std::chrono::milliseconds timeout) {
    return send_message_timeout<void>(this, messaging_verb::GOSSIP_ECHO, std::move(id), timeout, generation_number);
}

void messaging_service::register_gossip_shutdown(std::function<rpc::no_wait_type (inet_address from, rpc::optional<int64_t> generation_number)>&& func) {
    register_handler(this, messaging_verb::GOSSIP_SHUTDOWN, std::move(func));
}
future<> messaging_service::unregister_gossip_shutdown() {
    return unregister_handler(netw::messaging_verb::GOSSIP_SHUTDOWN);
}
future<> messaging_service::send_gossip_shutdown(msg_addr id, inet_address from, int64_t generation_number) {
    return send_message_oneway(this, messaging_verb::GOSSIP_SHUTDOWN, std::move(id), std::move(from), generation_number);
}

// gossip syn
void messaging_service::register_gossip_digest_syn(std::function<rpc::no_wait_type (const rpc::client_info& cinfo, gossip_digest_syn)>&& func) {
    register_handler(this, messaging_verb::GOSSIP_DIGEST_SYN, std::move(func));
}
future<> messaging_service::unregister_gossip_digest_syn() {
    return unregister_handler(netw::messaging_verb::GOSSIP_DIGEST_SYN);
}
future<> messaging_service::send_gossip_digest_syn(msg_addr id, gossip_digest_syn msg) {
    return send_message_oneway(this, messaging_verb::GOSSIP_DIGEST_SYN, std::move(id), std::move(msg));
}

// gossip ack
void messaging_service::register_gossip_digest_ack(std::function<rpc::no_wait_type (const rpc::client_info& cinfo, gossip_digest_ack)>&& func) {
    register_handler(this, messaging_verb::GOSSIP_DIGEST_ACK, std::move(func));
}
future<> messaging_service::unregister_gossip_digest_ack() {
    return unregister_handler(netw::messaging_verb::GOSSIP_DIGEST_ACK);
}
future<> messaging_service::send_gossip_digest_ack(msg_addr id, gossip_digest_ack msg) {
    return send_message_oneway(this, messaging_verb::GOSSIP_DIGEST_ACK, std::move(id), std::move(msg));
}

// gossip ack2
void messaging_service::register_gossip_digest_ack2(std::function<rpc::no_wait_type (const rpc::client_info& cinfo, gossip_digest_ack2)>&& func) {
    register_handler(this, messaging_verb::GOSSIP_DIGEST_ACK2, std::move(func));
}
future<> messaging_service::unregister_gossip_digest_ack2() {
    return unregister_handler(netw::messaging_verb::GOSSIP_DIGEST_ACK2);
}
future<> messaging_service::send_gossip_digest_ack2(msg_addr id, gossip_digest_ack2 msg) {
    return send_message_oneway(this, messaging_verb::GOSSIP_DIGEST_ACK2, std::move(id), std::move(msg));
}

void messaging_service::register_gossip_get_endpoint_states(std::function<future<gms::gossip_get_endpoint_states_response> (const rpc::client_info& cinfo, gms::gossip_get_endpoint_states_request request)>&& func) {
    register_handler(this, messaging_verb::GOSSIP_GET_ENDPOINT_STATES, std::move(func));
}
future<> messaging_service::unregister_gossip_get_endpoint_states() {
    return unregister_handler(messaging_verb::GOSSIP_GET_ENDPOINT_STATES);
}
future<gms::gossip_get_endpoint_states_response> messaging_service::send_gossip_get_endpoint_states(msg_addr id, std::chrono::milliseconds timeout, gms::gossip_get_endpoint_states_request request) {
    return send_message_timeout<future<gms::gossip_get_endpoint_states_response>>(this, messaging_verb::GOSSIP_GET_ENDPOINT_STATES, std::move(id), std::move(timeout), std::move(request));
}

void messaging_service::register_definitions_update(std::function<rpc::no_wait_type (const rpc::client_info& cinfo, std::vector<frozen_mutation> fm,
            rpc::optional<std::vector<canonical_mutation>> cm)>&& func) {
    register_handler(this, netw::messaging_verb::DEFINITIONS_UPDATE, std::move(func));
}
future<> messaging_service::unregister_definitions_update() {
    return unregister_handler(netw::messaging_verb::DEFINITIONS_UPDATE);
}
future<> messaging_service::send_definitions_update(msg_addr id, std::vector<frozen_mutation> fm, std::vector<canonical_mutation> cm) {
    return send_message_oneway(this, messaging_verb::DEFINITIONS_UPDATE, std::move(id), std::move(fm), std::move(cm));
}

void messaging_service::register_migration_request(std::function<future<rpc::tuple<std::vector<frozen_mutation>, std::vector<canonical_mutation>>>
        (const rpc::client_info&, rpc::optional<schema_pull_options>)>&& func) {
    register_handler(this, netw::messaging_verb::MIGRATION_REQUEST, std::move(func));
}
future<> messaging_service::unregister_migration_request() {
    return unregister_handler(netw::messaging_verb::MIGRATION_REQUEST);
}
future<rpc::tuple<std::vector<frozen_mutation>, rpc::optional<std::vector<canonical_mutation>>>> messaging_service::send_migration_request(msg_addr id,
        schema_pull_options options) {
    return send_message<future<rpc::tuple<std::vector<frozen_mutation>, rpc::optional<std::vector<canonical_mutation>>>>>(this, messaging_verb::MIGRATION_REQUEST,
            std::move(id), options);
}

void messaging_service::register_get_schema_version(std::function<future<frozen_schema>(unsigned, table_schema_version)>&& func) {
    register_handler(this, netw::messaging_verb::GET_SCHEMA_VERSION, std::move(func));
}
future<> messaging_service::unregister_get_schema_version() {
    return unregister_handler(netw::messaging_verb::GET_SCHEMA_VERSION);
}
future<frozen_schema> messaging_service::send_get_schema_version(msg_addr dst, table_schema_version v) {
    return send_message<frozen_schema>(this, messaging_verb::GET_SCHEMA_VERSION, dst, static_cast<unsigned>(dst.cpu_id), v);
}

void messaging_service::register_schema_check(std::function<future<utils::UUID>()>&& func) {
    register_handler(this, netw::messaging_verb::SCHEMA_CHECK, std::move(func));
}
future<> messaging_service::unregister_schema_check() {
    return unregister_handler(netw::messaging_verb::SCHEMA_CHECK);
}
future<utils::UUID> messaging_service::send_schema_check(msg_addr dst) {
    return send_message<utils::UUID>(this, netw::messaging_verb::SCHEMA_CHECK, dst);
}

// Wrapper for REPLICATION_FINISHED
void messaging_service::register_replication_finished(std::function<future<> (inet_address)>&& func) {
    register_handler(this, messaging_verb::REPLICATION_FINISHED, std::move(func));
}
future<> messaging_service::unregister_replication_finished() {
    return unregister_handler(messaging_verb::REPLICATION_FINISHED);
}
future<> messaging_service::send_replication_finished(msg_addr id, inet_address from) {
    // FIXME: getRpcTimeout : conf.request_timeout_in_ms
    return send_message_timeout<void>(this, messaging_verb::REPLICATION_FINISHED, std::move(id), 10000ms, std::move(from));
}

// Wrapper for REPAIR_GET_FULL_ROW_HASHES
void messaging_service::register_repair_get_full_row_hashes(std::function<future<repair_hash_set> (const rpc::client_info& cinfo, uint32_t repair_meta_id)>&& func) {
    register_handler(this, messaging_verb::REPAIR_GET_FULL_ROW_HASHES, std::move(func));
}
future<> messaging_service::unregister_repair_get_full_row_hashes() {
    return unregister_handler(messaging_verb::REPAIR_GET_FULL_ROW_HASHES);
}
future<repair_hash_set> messaging_service::send_repair_get_full_row_hashes(msg_addr id, uint32_t repair_meta_id) {
    return send_message<future<repair_hash_set>>(this, messaging_verb::REPAIR_GET_FULL_ROW_HASHES, std::move(id), repair_meta_id);
}

// Wrapper for REPAIR_GET_COMBINED_ROW_HASH
void messaging_service::register_repair_get_combined_row_hash(std::function<future<get_combined_row_hash_response> (const rpc::client_info& cinfo, uint32_t repair_meta_id, std::optional<repair_sync_boundary> common_sync_boundary)>&& func) {
    register_handler(this, messaging_verb::REPAIR_GET_COMBINED_ROW_HASH, std::move(func));
}
future<> messaging_service::unregister_repair_get_combined_row_hash() {
    return unregister_handler(messaging_verb::REPAIR_GET_COMBINED_ROW_HASH);
}
future<get_combined_row_hash_response> messaging_service::send_repair_get_combined_row_hash(msg_addr id, uint32_t repair_meta_id, std::optional<repair_sync_boundary> common_sync_boundary) {
    return send_message<future<get_combined_row_hash_response>>(this, messaging_verb::REPAIR_GET_COMBINED_ROW_HASH, std::move(id), repair_meta_id, std::move(common_sync_boundary));
}

void messaging_service::register_repair_get_sync_boundary(std::function<future<get_sync_boundary_response> (const rpc::client_info& cinfo, uint32_t repair_meta_id, std::optional<repair_sync_boundary> skipped_sync_boundary)>&& func) {
    register_handler(this, messaging_verb::REPAIR_GET_SYNC_BOUNDARY, std::move(func));
}
future<> messaging_service::unregister_repair_get_sync_boundary() {
    return unregister_handler(messaging_verb::REPAIR_GET_SYNC_BOUNDARY);
}
future<get_sync_boundary_response> messaging_service::send_repair_get_sync_boundary(msg_addr id, uint32_t repair_meta_id, std::optional<repair_sync_boundary> skipped_sync_boundary) {
    return send_message<future<get_sync_boundary_response>>(this, messaging_verb::REPAIR_GET_SYNC_BOUNDARY, std::move(id), repair_meta_id, std::move(skipped_sync_boundary));
}

// Wrapper for REPAIR_GET_ROW_DIFF
void messaging_service::register_repair_get_row_diff(std::function<future<repair_rows_on_wire> (const rpc::client_info& cinfo, uint32_t repair_meta_id, repair_hash_set set_diff, bool needs_all_rows)>&& func) {
    register_handler(this, messaging_verb::REPAIR_GET_ROW_DIFF, std::move(func));
}
future<> messaging_service::unregister_repair_get_row_diff() {
    return unregister_handler(messaging_verb::REPAIR_GET_ROW_DIFF);
}
future<repair_rows_on_wire> messaging_service::send_repair_get_row_diff(msg_addr id, uint32_t repair_meta_id, repair_hash_set set_diff, bool needs_all_rows) {
    return send_message<future<repair_rows_on_wire>>(this, messaging_verb::REPAIR_GET_ROW_DIFF, std::move(id), repair_meta_id, std::move(set_diff), needs_all_rows);
}

// Wrapper for REPAIR_PUT_ROW_DIFF
void messaging_service::register_repair_put_row_diff(std::function<future<> (const rpc::client_info& cinfo, uint32_t repair_meta_id, repair_rows_on_wire row_diff)>&& func) {
    register_handler(this, messaging_verb::REPAIR_PUT_ROW_DIFF, std::move(func));
}
future<> messaging_service::unregister_repair_put_row_diff() {
    return unregister_handler(messaging_verb::REPAIR_PUT_ROW_DIFF);
}
future<> messaging_service::send_repair_put_row_diff(msg_addr id, uint32_t repair_meta_id, repair_rows_on_wire row_diff) {
    return send_message<void>(this, messaging_verb::REPAIR_PUT_ROW_DIFF, std::move(id), repair_meta_id, std::move(row_diff));
}

// Wrapper for REPAIR_ROW_LEVEL_START
void messaging_service::register_repair_row_level_start(std::function<future<repair_row_level_start_response> (const rpc::client_info& cinfo, uint32_t repair_meta_id, sstring keyspace_name, sstring cf_name, dht::token_range range, row_level_diff_detect_algorithm algo, uint64_t max_row_buf_size, uint64_t seed, unsigned remote_shard, unsigned remote_shard_count, unsigned remote_ignore_msb, sstring remote_partitioner_name, table_schema_version schema_version, rpc::optional<streaming::stream_reason> reason)>&& func) {
    register_handler(this, messaging_verb::REPAIR_ROW_LEVEL_START, std::move(func));
}
future<> messaging_service::unregister_repair_row_level_start() {
    return unregister_handler(messaging_verb::REPAIR_ROW_LEVEL_START);
}
future<rpc::optional<repair_row_level_start_response>> messaging_service::send_repair_row_level_start(msg_addr id, uint32_t repair_meta_id, sstring keyspace_name, sstring cf_name, dht::token_range range, row_level_diff_detect_algorithm algo, uint64_t max_row_buf_size, uint64_t seed, unsigned remote_shard, unsigned remote_shard_count, unsigned remote_ignore_msb, sstring remote_partitioner_name, table_schema_version schema_version, streaming::stream_reason reason) {
    return send_message<rpc::optional<repair_row_level_start_response>>(this, messaging_verb::REPAIR_ROW_LEVEL_START, std::move(id), repair_meta_id, std::move(keyspace_name), std::move(cf_name), std::move(range), algo, max_row_buf_size, seed, remote_shard, remote_shard_count, remote_ignore_msb, std::move(remote_partitioner_name), std::move(schema_version), reason);
}

// Wrapper for REPAIR_ROW_LEVEL_STOP
void messaging_service::register_repair_row_level_stop(std::function<future<> (const rpc::client_info& cinfo, uint32_t repair_meta_id, sstring keyspace_name, sstring cf_name, dht::token_range range)>&& func) {
    register_handler(this, messaging_verb::REPAIR_ROW_LEVEL_STOP, std::move(func));
}
future<> messaging_service::unregister_repair_row_level_stop() {
    return unregister_handler(messaging_verb::REPAIR_ROW_LEVEL_STOP);
}
future<> messaging_service::send_repair_row_level_stop(msg_addr id, uint32_t repair_meta_id, sstring keyspace_name, sstring cf_name, dht::token_range range) {
    return send_message<void>(this, messaging_verb::REPAIR_ROW_LEVEL_STOP, std::move(id), repair_meta_id, std::move(keyspace_name), std::move(cf_name), std::move(range));
}

// Wrapper for REPAIR_GET_ESTIMATED_PARTITIONS
void messaging_service::register_repair_get_estimated_partitions(std::function<future<uint64_t> (const rpc::client_info& cinfo, uint32_t repair_meta_id)>&& func) {
    register_handler(this, messaging_verb::REPAIR_GET_ESTIMATED_PARTITIONS, std::move(func));
}
future<> messaging_service::unregister_repair_get_estimated_partitions() {
    return unregister_handler(messaging_verb::REPAIR_GET_ESTIMATED_PARTITIONS);
}
future<uint64_t> messaging_service::send_repair_get_estimated_partitions(msg_addr id, uint32_t repair_meta_id) {
    return send_message<future<uint64_t>>(this, messaging_verb::REPAIR_GET_ESTIMATED_PARTITIONS, std::move(id), repair_meta_id);
}

// Wrapper for REPAIR_SET_ESTIMATED_PARTITIONS
void messaging_service::register_repair_set_estimated_partitions(std::function<future<> (const rpc::client_info& cinfo, uint32_t repair_meta_id, uint64_t estimated_partitions)>&& func) {
    register_handler(this, messaging_verb::REPAIR_SET_ESTIMATED_PARTITIONS, std::move(func));
}
future<> messaging_service::unregister_repair_set_estimated_partitions() {
    return unregister_handler(messaging_verb::REPAIR_SET_ESTIMATED_PARTITIONS);
}
future<> messaging_service::send_repair_set_estimated_partitions(msg_addr id, uint32_t repair_meta_id, uint64_t estimated_partitions) {
    return send_message<void>(this, messaging_verb::REPAIR_SET_ESTIMATED_PARTITIONS, std::move(id), repair_meta_id, estimated_partitions);
}

// Wrapper for REPAIR_GET_DIFF_ALGORITHMS
void messaging_service::register_repair_get_diff_algorithms(std::function<future<std::vector<row_level_diff_detect_algorithm>> (const rpc::client_info& cinfo)>&& func) {
    register_handler(this, messaging_verb::REPAIR_GET_DIFF_ALGORITHMS, std::move(func));
}
future<> messaging_service::unregister_repair_get_diff_algorithms() {
    return unregister_handler(messaging_verb::REPAIR_GET_DIFF_ALGORITHMS);
}
future<std::vector<row_level_diff_detect_algorithm>> messaging_service::send_repair_get_diff_algorithms(msg_addr id) {
    return send_message<future<std::vector<row_level_diff_detect_algorithm>>>(this, messaging_verb::REPAIR_GET_DIFF_ALGORITHMS, std::move(id));
}

// Wrapper for NODE_OPS_CMD
void messaging_service::register_node_ops_cmd(std::function<future<node_ops_cmd_response> (const rpc::client_info& cinfo, node_ops_cmd_request)>&& func) {
    register_handler(this, messaging_verb::NODE_OPS_CMD, std::move(func));
}
future<> messaging_service::unregister_node_ops_cmd() {
    return unregister_handler(messaging_verb::NODE_OPS_CMD);
}
future<node_ops_cmd_response> messaging_service::send_node_ops_cmd(msg_addr id, node_ops_cmd_request req) {
    return send_message<future<node_ops_cmd_response>>(this, messaging_verb::NODE_OPS_CMD, std::move(id), std::move(req));
}

void messaging_service::register_group0_peer_exchange(std::function<future<service::group0_peer_exchange>(const rpc::client_info&, rpc::opt_time_point, std::vector<raft::server_address>)>&& func) {
   register_handler(this, netw::messaging_verb::GROUP0_PEER_EXCHANGE, std::move(func));
}
future<> messaging_service::unregister_group0_peer_exchange() {
   return unregister_handler(netw::messaging_verb::GROUP0_PEER_EXCHANGE);
}
future<service::group0_peer_exchange> messaging_service::send_group0_peer_exchange(msg_addr id, clock_type::time_point timeout, const std::vector<raft::server_address>& peers) {
   return send_message_timeout<service::group0_peer_exchange>(this, messaging_verb::GROUP0_PEER_EXCHANGE, std::move(id), timeout, peers);
}

void messaging_service::register_group0_modify_config(std::function<future<>(const rpc::client_info&, rpc::opt_time_point, raft::group_id gid, std::vector<raft::server_address> add, std::vector<raft::server_id> del)>&& func) {
   register_handler(this, netw::messaging_verb::GROUP0_MODIFY_CONFIG, std::move(func));
}

future<> messaging_service::unregister_group0_modify_config() {
   return unregister_handler(netw::messaging_verb::GROUP0_MODIFY_CONFIG);
}

future<> messaging_service::send_group0_modify_config(msg_addr id, clock_type::time_point timeout, raft::group_id gid, const std::vector<raft::server_address>& add, const std::vector<raft::server_id>& del) {
   return send_message_timeout<void>(this, messaging_verb::GROUP0_MODIFY_CONFIG, std::move(id), timeout, std::move(gid), add, del);
}

void init_messaging_service(sharded<messaging_service>& ms,
                messaging_service::config mscfg, netw::messaging_service::scheduling_config scfg, const db::config& db_config) {
    using encrypt_what = messaging_service::encrypt_what;
    using namespace seastar::tls;

    const auto& ssl_opts = db_config.server_encryption_options();
    auto encrypt = utils::get_or_default(ssl_opts, "internode_encryption", "none");

    if (encrypt == "all") {
        mscfg.encrypt = encrypt_what::all;
    } else if (encrypt == "dc") {
        mscfg.encrypt = encrypt_what::dc;
    } else if (encrypt == "rack") {
        mscfg.encrypt = encrypt_what::rack;
    }

    std::shared_ptr<credentials_builder> creds;

    if (mscfg.encrypt != encrypt_what::none) {
        creds = std::make_shared<credentials_builder>();
        utils::configure_tls_creds_builder(*creds, std::move(ssl_opts)).get();
    }

    // Init messaging_service
    // Delay listening messaging_service until gossip message handlers are registered

    ms.start(mscfg, scfg, creds).get();
}

future<> uninit_messaging_service(sharded<messaging_service>& ms) {
    // Do not destroy instances for real, as other services need them, just call .stop()
    return ms.invoke_on_all(&messaging_service::stop);
}

} // namespace net