dns_client.h

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// Copyright (C) 2013-2025 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
#ifndef DNS_CLIENT_H
#define DNS_CLIENT_H
 
#include <asiolink/io_service.h>
#include <asiodns/io_fetch.h>
#include <d2srv/d2_tsig_key.h>
#include <d2srv/d2_update_message.h>
#include <util/buffer.h>
 
namespace isc {
namespace d2 {
 
class DNSClient;
typedef boost::shared_ptr<DNSClient> DNSClientPtr;

class DNSClientImpl;

class DNSClient {
public:

    enum Protocol {
        UDP,
        TCP
    };

    enum Status : uint16_t {
        SUCCESS = 0,            
        TIMEOUT = 1,            
        IO_STOPPED = 2,         
        INVALID_RESPONSE = 3,   
        OTHER = 4,              
    };

    static std::string const& statusToText(Status const& status) {
        static std::vector<std::string> const text_vector {
            "SUCCESS",
            "TIMEOUT",
            "IO_STOPPED",
            "INVALID_RESPONSE",
            "OTHER",
        };
        static std::string const unknown("UNKNOWN");
        return (status < text_vector.size() ? text_vector[status] : unknown);
    }

    class Callback {
    public:
        virtual ~Callback() { }

        virtual void operator()(DNSClient::Status status) = 0;
    };

    DNSClient(D2UpdateMessagePtr& response_placeholder, Callback* callback,
              const Protocol proto = UDP);

    ~DNSClient();

    void stop();


private:
    DNSClient(const DNSClient& source);
    DNSClient& operator=(const DNSClient& source);
 
public:

    static unsigned int getMaxTimeout();

    void doUpdate(const asiolink::IOServicePtr& io_service,
                  const asiolink::IOAddress& ns_addr,
                  const uint16_t ns_port,
                  D2UpdateMessage& update,
                  const unsigned int wait,
                  const D2TsigKeyPtr& tsig_key = D2TsigKeyPtr());
 
private:
    std::unique_ptr<DNSClientImpl> impl_;
};
 
} // namespace d2
} // namespace isc
 
#endif // DNS_CLIENT_H