mcs/class/System/Mono.Net.Dns/DnsResponse.cs

   1 //
   2 // Mono.Net.Dns.DnsResponse
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo.mono@gmail.com)
   6 //
   7 // Copyright 2011 Gonzalo Paniagua Javier
   8 //
   9 // Licensed under the Apache License, Version 2.0 (the "License");
  10 // you may not use this file except in compliance with the License.
  11 // You may obtain a copy of the License at
  12 //
  13 // http://www.apache.org/licenses/LICENSE-2.0
  14 //
  15 // Unless required by applicable law or agreed to in writing, software
  16 // distributed under the License is distributed on an "AS IS" BASIS,
  17 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  18 // See the License for the specific language governing permissions and
  19 // limitations under the License.
  20 //
  21 using System;
  22 using System.Collections.Generic;
  23 using System.Collections.ObjectModel;
  24 using System.IO;
  25 using System.Text;
  26
  27 namespace Mono.Net.Dns {
  28         class DnsResponse : DnsPacket {
  29                 static readonly ReadOnlyCollection<DnsResourceRecord> EmptyRR = new ReadOnlyCollection<DnsResourceRecord> (new DnsResourceRecord [0]);
  30                 static readonly ReadOnlyCollection<DnsQuestion> EmptyQS = new ReadOnlyCollection<DnsQuestion> (new DnsQuestion [0]);
  31
  32                 ReadOnlyCollection<DnsQuestion> question;
  33                 ReadOnlyCollection<DnsResourceRecord> answer;
  34                 ReadOnlyCollection<DnsResourceRecord> authority;
  35                 ReadOnlyCollection<DnsResourceRecord> additional;
  36                 int offset = DnsHeader.DnsHeaderLength;
  37
  38                 public DnsResponse (byte [] buffer, int length)
  39                         : base (buffer, length)
  40                 {
  41                 }
  42
  43                 public void Reset ()
  44                 {
  45                         question = null;
  46                         answer = null;
  47                         authority = null;
  48                         additional = null;
  49                         for (int i = 0; i < packet.Length; i++)
  50                                 packet [i] = 0;
  51                 }
  52
  53                 ReadOnlyCollection<DnsResourceRecord> GetRRs (int count)
  54                 {
  55                         if (count <= 0)
  56                                 return EmptyRR;
  57
  58                         List<DnsResourceRecord> records = new List<DnsResourceRecord>(count);
  59                         for (int i = 0; i < count; i++)
  60                                 records.Add (DnsResourceRecord.CreateFromBuffer (this, position, ref offset));
  61                         return records.AsReadOnly ();
  62                 }
  63
  64                 ReadOnlyCollection<DnsQuestion> GetQuestions (int count)
  65                 {
  66                         if (count <= 0)
  67                                 return EmptyQS;
  68
  69                         List<DnsQuestion> records = new List<DnsQuestion> (count);
  70                         for(int i = 0; i < count; i++) {
  71                                 DnsQuestion record = new DnsQuestion ();
  72                                 offset = record.Init (this, offset);
  73                                 records.Add (record);
  74                         }
  75                         return records.AsReadOnly ();
  76                 }
  77
  78                 public ReadOnlyCollection<DnsQuestion> GetQuestions ()
  79                 {
  80                         if (question == null)
  81                                 question = GetQuestions (Header.QuestionCount);
  82                         return question;
  83                 }
  84
  85                 public ReadOnlyCollection<DnsResourceRecord> GetAnswers ()
  86                 {
  87                         if (answer == null) {
  88                                 GetQuestions ();
  89                                 answer = GetRRs (Header.AnswerCount);
  90                         }
  91                         return answer;
  92                 }
  93
  94                 public ReadOnlyCollection<DnsResourceRecord> GetAuthority ()
  95                 {
  96                         if (authority == null) {
  97                                 GetQuestions ();
  98                                 GetAnswers ();
  99                                 authority = GetRRs (Header.AuthorityCount);
 100                         }
 101                         return authority;
 102                 }
 103
 104                 public ReadOnlyCollection<DnsResourceRecord> GetAdditional ()
 105                 {
 106                         if (additional == null) {
 107                                 GetQuestions ();
 108                                 GetAnswers ();
 109                                 GetAuthority ();
 110                                 additional = GetRRs (Header.AdditionalCount);
 111                         }
 112                         return additional;
 113                 }
 114
 115                 public override string ToString ()
 116                 {
 117                         StringBuilder sb = new StringBuilder();
 118                         sb.Append(Header);
 119                         sb.Append("Question:\r\n");
 120                         foreach(DnsQuestion q in GetQuestions()) {
 121                                 sb.AppendFormat("\t{0}\r\n", q);
 122                         }
 123                         sb.Append("Answer(s):\r\n");
 124                         foreach(DnsResourceRecord q in GetAnswers()) {
 125                                 sb.AppendFormat("\t{0}\r\n", q);
 126                         }
 127                         sb.Append("Authority:\r\n");
 128                         foreach(DnsResourceRecord q in GetAuthority()) {
 129                                 sb.AppendFormat("\t{0}\r\n", q);
 130                         }
 131                         sb.Append("Additional:\r\n");
 132                         foreach(DnsResourceRecord q in GetAdditional()) {
 133                                 sb.AppendFormat("\t{0}\r\n", q);
 134                         }
 135                         return sb.ToString();
 136                 }
 137         }
 138 }
 139