#ifndef DNS_QUERY_PORT
	#include "StdAfx.h"

	#define DNS_QUERY_PORT		53				//DNS服務器的監聽端口
	#define DNSPACKET_BUFFSIZE	512				//DNSPACKET數據緩沖區的尺寸
	#define DNS_SRV_ADDR		"202.96.128.68"	//DNS服務器的IP地址

	
class DNS
{
private:
	DNS(){};
public:
	enum _DNSCLASS
	{
		classIN = 1,
		classCS,
		classCH,
		classHS,
		classANY=255
	};

	enum _DNSTYPE
	{
		//定義DNS類型
		typeA = 1,
		typeNS,
		typeMD,
		typeMF,
		typeCNAME,
		typeSOA,
		typeMB,
		typeMG,
		typeMR,
		typeNULL,
		typeWKS,
		typePTR,
		typeHINFO,
		typeMINFO,
		typeMX,
		typeTXT,
		typeAXFR = 252,
		typeMAILB,
		typeMAILA,
		typeAll
	};

	struct _DNSHEADER
	{
		//DNS頭
		USHORT	id;
		
		USHORT	RD		: 1;
		USHORT	TC		: 1;
		USHORT	AA		: 1;
		USHORT	Opcode	: 4;
		USHORT	QR		: 1;
		
		USHORT	RCODE	: 4;
		USHORT	Z		: 3;
		USHORT	RA		: 1;
		
		USHORT	QDCOUNT;		//Count of Queryes
		USHORT	ANCOUNT;		//Count of Answers
		USHORT	NSCOUNT;		//Count of NameServer
		USHORT	ARCOUNT;		//Count of Address Records(A記錄)
	public:
		_DNSHEADER()
		{
			memset(this, 0, sizeof(this));
		}
		inline void Normalize()
		{
			//從字節序轉變成網絡序或逆轉
			QDCOUNT = htons(QDCOUNT);
			ANCOUNT = htons(ANCOUNT);
			NSCOUNT = htons(NSCOUNT);
			ARCOUNT = htons(ARCOUNT);
		}
	};

	struct _DNSRR;
	struct _DNSQUESTION;
	
	struct _MXRECORD
	{
		char			*lpSrvName;
		char			*lpSrvAddr;
		int				nSrvNameLen;
		int				nSrvAddrLen;
		unsigned long	ip;

		_MXRECORD():lpSrvName(NULL),lpSrvAddr(NULL){};
		~_MXRECORD()
		{
			Empty();
		};
		
		inline void Empty()
		{
			if(lpSrvName!=NULL)
			{	
				::free(lpSrvName);
				lpSrvName	=NULL;
			}
			if(lpSrvAddr!=NULL)
			{
				::free(lpSrvAddr);
				lpSrvAddr	=NULL;
			}
		};
		inline bool Fill(_DNSRR& dr);
	};

	struct _DNSPACKET
	{
		//DNS包
	public:
		_DNSHEADER	Header;
	private:
		char		pvtData[DNSPACKET_BUFFSIZE-sizeof(_DNSHEADER)];
		char		mxName[DNSPACKET_BUFFSIZE-sizeof(_DNSHEADER)];
		USHORT		mxNameLen;
		
		inline bool	IsInMXName(const char* const lpSrv);
	public:
		USHORT Offset;
		
		_DNSPACKET()		{Header.id	= 0;Empty();};
		inline	void	Normalize()	{Header.Normalize();}
		inline	int		Empty();

		inline	bool	QueryDNSServer(SOCKET sock,char* const lpHost,const struct sockaddr_in FAR * lphDnsSrv,_DNSTYPE type=typeAll,_DNSCLASS dnsClass=classIN);
		inline	bool	WaitRecvFromDNSServer(SOCKET sock,struct sockaddr_in FAR* from,int nSeconds=2);
		inline	bool	GetDNSQuestion(_DNSQUESTION& dq);
		inline	bool	GetDNSRR(_DNSRR& dr);
		inline	bool	GetMXHostSet(char* const lpSrvName,char* const lpDnsSrv=DNS_SRV_ADDR,int nCount=5);
		inline	bool	GetMX(_MXRECORD& mr);
		inline	struct hostent FAR * GetMXHost();

		//重載操作符BYTE*()
		inline operator BYTE*()			{return (BYTE*)this;};
		inline USHORT	GetSize()const	{return DNSPACKET_BUFFSIZE;};
	};

	struct _QNAME
	{
		//DNS字符串結構，保存名字
		char	Data[DNSPACKET_BUFFSIZE];
	public:
		USHORT		Offset;
		
		inline	void Empty()
		{
			memset(Data, 0, sizeof(Data));
			Offset = 0;
		}
		
		_QNAME()	{Empty();	};
		inline	USHORT GetSize()const {return Offset+1;	};
		
		inline	int		Add(LPCSTR str);
		inline	char*	Get(int& nLen);
		inline	bool	Add(_DNSPACKET& dns, USHORT& nOffset);
		inline	bool	Fill(_DNSPACKET& dns, USHORT& nOffset);
	};
	
	struct _DNSA
	{
		//DNS地址
		long	addr;

		_DNSA()
		{
			addr = 0;
		}
		inline	void _DNSA::Normalize()
		{
			//將地址由字節序轉換為網絡序
			addr = htonl(addr);
		}
		
		inline	bool	Add(_DNSPACKET& dns, USHORT& nOffset);
		inline	bool	Fill(_DNSPACKET& dns, USHORT& nOffset);
	};
	
	struct _DNSNS
	{
		//DNS服務器的名字
		_QNAME	Server;
		
	public:
		inline void Empty()
		{
			Server.Empty();
		}
		
		_DNSNS()
		{
			Empty();
		}
		
		inline bool Fill(_DNSPACKET& dns, USHORT& nOffset)
		{
			return Server.Fill(dns, nOffset);
		}
		
		inline bool Add(_DNSPACKET& dns, USHORT& nOffset)
		{
			return Server.Add(dns, nOffset);
		}
	};
	
	struct _DNSMX
	{
		//MX記錄
		USHORT	Reference;
		_QNAME	Exchange;
		
	public:
		_DNSMX()
		{
			Empty();
		}
		inline	void Empty()
		{
			Reference = 0;
			Exchange.Empty();
		}
		inline	void Normalize()
		{
			//轉變字節序為網絡序
			Reference	= htons(Reference);
		}
		
		inline	bool	Fill(_DNSPACKET& dns, USHORT& nOffset);
		inline	bool	Add(_DNSPACKET& dns, USHORT& nOffset);
	};
	
	struct _DNSSOA
	{
		_QNAME	mName;
		_QNAME	rName;
		long	Serial;
		long	Refresh;
		long	Retry;
		long	Expire;
		long	Minimum;
		
	public:
		_DNSSOA()
		{
			Empty();
		}
		inline	void Empty()
		{
			mName.Empty();
			rName.Empty();
			memset(&Serial, 0, 5*4);
		}
		inline	void Normalize()
		{
			Serial	= htonl(Serial);
			Refresh = htonl(Refresh);
			Retry	= htonl(Retry);
			Expire	= htonl(Expire);
			Minimum	= htonl(Minimum);
		}
		
		inline	bool	Fill(_DNSPACKET& dns, USHORT& nOffset);
		inline	bool	Add(_DNSPACKET& dns, USHORT& nOffset);
	};
	
	struct _DNSQUESTION
	{
	public:
		_QNAME		qName;
		_DNSTYPE	Type;
		_DNSCLASS	Class;
	public:
		_DNSQUESTION()
		{
			Empty();
		}
		inline	void Empty()
		{
			qName.Empty();
			Type	= typeAll;
			Class	= classANY;
		}
		inline	void _DNSQUESTION::Normalize()
		{
			Type  = (_DNSTYPE)htons(Type);
			Class = (_DNSCLASS)htons(Class);
		}
		
		inline	bool	Add(_DNSPACKET& dns, USHORT& nOffset);
		inline	bool	Fill(_DNSPACKET& dns, USHORT& nOffset);
		inline	USHORT	GetSize()const{return qName.GetSize() + 4;};
	};
	
	struct _DNSRR
	{
		_DNSQUESTION	q;
		long			ttl;
		USHORT			rDataLen;
		BYTE*			rData;
	public:
		_DNSPACKET*		pDns;
		USHORT			Offset;
	public:
		_DNSRR(_DNSPACKET& rDns)
		{
			pDns		= &rDns;
			rData		= NULL;
			Empty();
		}
		~_DNSRR()
		{
			Empty();
		}
		inline	void Normalize()
		{
			q.Normalize();
			ttl		= htonl(ttl);
			rDataLen= htons(rDataLen);
		}
		
		inline	void	Empty();
		inline	bool	Add(_DNSPACKET& dns, USHORT& nOffset);
		inline	bool	Fill(_DNSPACKET& dns, USHORT& nOffset);
		inline	bool	GetDNSRecord(_DNSSOA& ds);
		inline	bool	GetDNSRecord(_DNSNS& dn);
		inline	bool	GetDNSRecord(_DNSMX& dm);
		inline	bool	GetDNSRecord(_DNSA& da);

		inline USHORT	GetSize()const{return rDataLen;};
	};

	static SOCKET CreateDNSSocket(char *lpDnsSrv,struct sockaddr_in& hDnsSrv);
};

#endif