using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using NewLife.Messaging;
using NewLife.Reflection;
using NewLife.Serialization;
namespace NewLife.Net.DNS
{
/// <summary>DNS实体类基类</summary>
/// <remarks>
/// 参考博客园 @看那边的人 <a target="_blank" href="http://www.cnblogs.com/topdog/archive/2011/11/15/2250185.html">DIY一个DNS查询器：了解DNS协议</a>
/// <a target="_blank" href="http://www.cnblogs.com/topdog/archive/2011/11/21/2257597.html">DIY一个DNS查询器：程序实现</a>
/// </remarks>
public class DNSEntity : Message<DNSEntity>
{
#region 属性
private DNSHeader _Header = new DNSHeader();
/// <summary>头部</summary>
public DNSHeader Header { get { return _Header; } set { _Header = value; } }
[FieldSize("_Header._Questions")]
private DNSQuery[] _Questions;
/// <summary>请求段</summary>
public DNSQuery[] Questions { get { return _Questions; } set { _Questions = value; } }
[FieldSize("_Header._Answers")]
private DNSRecord[] _Answers;
/// <summary>回答段</summary>
public DNSRecord[] Answers { get { return _Answers; } set { _Answers = value; } }
[FieldSize("_Header._Authorities")]
private DNSRecord[] _Authoritis;
/// <summary>授权段</summary>
public DNSRecord[] Authoritis { get { return _Authoritis; } set { _Authoritis = value; } }
[FieldSize("_Header._Additionals")]
private DNSRecord[] _Additionals;
/// <summary>附加段</summary>
public DNSRecord[] Additionals { get { return _Additionals; } set { _Additionals = value; } }
#endregion
#region 扩展属性
///// <summary>是否响应</summary>
//public Boolean Response { get { return Header.Response; } set { Header.Response = value; } }
//DNSQuery Question
//{
// get
// {
// if (Questions == null || Questions.Length < 1) Questions = new DNSQuery[] { new DNSQuery() };
// return Questions[0];
// }
//}
///// <summary>名称</summary>
//public virtual String Name { get { return Question.Name; } set { Question.Name = value; } }
///// <summary>查询类型</summary>
//public virtual DNSQueryType Type { get { return Question.Type; } set { Question.Type = value; } }
///// <summary>协议组</summary>
//public virtual DNSQueryClass Class { get { return Question.Class; } set { Question.Class = value; } }
/// <summary>获取响应</summary>
/// <param name="create"></param>
/// <returns></returns>
internal protected DNSRecord GetAnswer(Boolean create = false)
{
var qs = Questions;
if (qs == null || qs.Length == 0) return null;
var type = qs.First().Type;
if (Answers == null || Answers.Length < 1)
{
if (!create) return null;
Answers = new DNSRecord[] { CreateRecord(type) };
}
foreach (var item in Answers)
{
if (item.Type == type) return item;
}
return Answers[0];
}
///// <summary>是否PTR类型</summary>
//public Boolean IsPTR { get { return Type == DNSQueryType.PTR; } }
#endregion
#region 读写
/// <summary>把当前对象写入到数据流中去</summary>
/// <param name="stream"></param>
/// <param name="forTcp">是否是Tcp，Tcp需要增加整个流长度</param>
public void Write(Stream stream, Boolean forTcp)
{
if (forTcp)
{
// 必须独立写然后再补长度，否则内部字符串长度偏移不正确
var ms = new MemoryStream();
Write(ms, null);
stream.Write(((Int16)ms.Length).GetBytes(false));
ms.WriteTo(stream);
}
else
Write(stream, null);
}
/// <summary>获取当前对象的数据流</summary>
/// <param name="forTcp">是否是Tcp，Tcp需要增加整个流长度</param>
/// <returns></returns>
public Stream GetStream(Boolean forTcp)
{
var ms = new MemoryStream();
Write(ms, forTcp);
ms.Position = 0;
return ms;
}
/// <summary>从数据中读取对象</summary>
/// <param name="data"></param>
/// <param name="forTcp">是否是Tcp，Tcp需要增加整个流长度</param>
/// <returns></returns>
public static DNSEntity Read(Byte[] data, Boolean forTcp)
{
if (data == null || data.Length < 1) return null;
return Read(new MemoryStream(data), forTcp);
}
/// <summary>从数据流中读取对象，返回<see cref="DNS_A"/>、<see cref="DNS_PTR"/>等真实对象</summary>
/// <param name="stream"></param>
/// <param name="forTcp">是否是Tcp，Tcp需要增加整个流长度</param>
/// <returns></returns>
public static DNSEntity Read(Stream stream, Boolean forTcp)
{
// 跳过2个字节的长度
if (forTcp)
{
// 必须全部先读出来，否则内部的字符串映射位移不正确
//var data = new Byte[2];
//stream.Read(data, 0, data.Length);
//// 网络序变为主机序
//Array.Reverse(data);
//var len = BitConverter.ToInt16(data, 0);
//data = new Byte[len];
//stream.Read(data, 0, data.Length);
var len = stream.ReadBytes(2).ToUInt16(0, false);
var data = stream.ReadBytes(len);
stream = new MemoryStream(data);
}
return Read(stream);
}
/// <summary>创建序列化器</summary>
/// <param name="isRead"></param>
/// <returns></returns>
protected override IFormatterX CreateFormatter(Boolean isRead)
{
var fm = base.CreateFormatter(isRead);
fm.Encoding = Encoding.UTF8;
fm.UseProperty = false;
var bn = fm as Binary;
if (bn != null)
{
bn.EncodeInt = false;
bn.UseFieldSize = true;
bn.UseRef = false;
bn.AddHandler<BinaryDNS>();
}
return fm;
}
#endregion
#region 注册子类型
static Dictionary<DNSQueryType, Type> entitytypes = new Dictionary<DNSQueryType, Type>();
static DNSEntity()
{
foreach (var item in typeof(DNSRecord).GetAllSubclasses())
{
if (item == typeof(DNSRecord)) continue;
var dr = item.CreateInstance() as DNSRecord;
if (dr != null) entitytypes.Add(dr.Type, item);
}
}
/// <summary>创建指定类型的记录</summary>
/// <param name="qt"></param>
/// <returns></returns>
public static DNSRecord CreateRecord(DNSQueryType qt)
{
Type type = null;
if (!entitytypes.TryGetValue(qt, out type) || type == null) return null;
return type.CreateInstance() as DNSRecord;
}
#endregion
#region 辅助
/// <summary>复制</summary>
/// <param name="entity"></param>
public virtual DNSEntity CloneFrom(DNSEntity entity)
{
var de = this;
de.Header = entity.Header;
de.Questions = entity.Questions;
de.Answers = entity.Answers;
de.Authoritis = entity.Authoritis;
de.Additionals = entity.Additionals;
return de;
}
/// <summary>已重载。</summary>
/// <returns></returns>
[DebuggerHidden]
public override String ToString()
{
var rs = Questions;
if (!Header.Response)
{
if (rs != null && rs.Length > 0)
return rs[0].ToString();
}
else
{
var sb = new StringBuilder();
if (rs != null && rs.Length > 0)
sb.AppendFormat("[{0}]", rs[0]);
if (Answers != null && Answers.Length > 0)
{
foreach (var item in Answers)
{
if (sb.Length > 0) sb.Append(" ");
sb.Append(item);
}
}
else if (Authoritis != null && Authoritis.Length > 0)
{
foreach (var item in Authoritis)
{
if (sb.Length > 0) sb.Append(" ");
sb.Append(item);
}
}
else if (Header.ResponseCode == DNSRcodeType.NameError)
sb.Append("No such name");
return sb.ToString();
//return String.Format("Response {0}", sb);
}
return base.ToString();
}
#endregion
}
}
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