mDNSMacOSX/BonjourTop/source/DNSFrame.cpp

   1 //
   2 //  DNSFrame.cpp
   3 //  TestTB
   4 //
   5 //  Created by Terrin Eager on 9/26/12.
   6 //
   7 //
   8
   9 #include "DNSFrame.h"
  10
  11 #define DNS_LABEL_MAX_LENGTH    63
  12 #define DNS_NAME_MAX_LENGTH     255
  13
  14 void CDNSRecord::GetDnsRecordName(BJString& ReturnString,int nLabelToSkip,int nMaxLabel)
  15 {
  16     GetDnsRecordNameFromBuffer(m_pStartofRec, ReturnString, nLabelToSkip, nMaxLabel);
  17 }
  18
  19 void CDNSRecord::GetDnsRecordNameFromBuffer(BJ_UINT8* pBuffer,BJString& ReturnString,int nLabelToSkip,int nMaxLabel)
  20 {
  21     BJ_UINT8* pNameBuffer = NULL;
  22     int nOffset = 0;
  23    // char* pTemp = pReturnBuffer;
  24     int nCharCount  = 0;
  25     int nSkippedLabels = 0;
  26     int nLabelProcessed = 0;
  27     ReturnString.Set(NULL,255);
  28
  29     if (ReturnString.GetBuffer() == NULL)
  30         return;
  31
  32     pNameBuffer = pBuffer;
  33     if (pNameBuffer == NULL)
  34     {
  35         return;
  36     }
  37
  38     while (ReturnString.GetBufferLength() < 1024)
  39     {
  40         nCharCount = *pNameBuffer++;
  41         if (nCharCount == 0)
  42             break;
  43
  44         if ((nCharCount&(DNS_NAME_OFFSET_MASK)) == DNS_NAME_OFFSET_MASK)
  45         {
  46             nOffset = *pNameBuffer++;
  47             nOffset |= (nCharCount&(~DNS_NAME_OFFSET_MASK)) << 8;
  48             pNameBuffer = m_pDNSFrame->GetBuffer() + nOffset;
  49             continue;
  50         }
  51
  52         if (nCharCount > DNS_LABEL_MAX_LENGTH)
  53         {
  54             printf("label too long %d\n",nCharCount);
  55             break;
  56         }
  57
  58         if (ReturnString.GetLength() + nCharCount + 1 > DNS_NAME_MAX_LENGTH) // + 1 is for the '.' added later on
  59         {
  60             printf("Name exceeded limit allowed for DNS: %d\n", ReturnString.GetLength() + nCharCount + 1);
  61             break;
  62         }
  63
  64         if (nLabelToSkip > nSkippedLabels)
  65         {
  66             nSkippedLabels++;
  67             pNameBuffer += nCharCount;
  68             continue;
  69         }
  70         ReturnString.Append((char*)pNameBuffer, nCharCount);
  71         pNameBuffer+= nCharCount;
  72         nLabelProcessed++;
  73
  74         if (nLabelProcessed >= nMaxLabel)
  75             return;
  76
  77         ReturnString += ".";
  78     }
  79 }
  80
  81
  82
  83
  84 CDNSFrame::CDNSFrame()
  85 {
  86
  87     for(int nIndex=0; nIndex < MAX_DNS_RECORDS_PER_FRAME; nIndex++)
  88         m_dnsItems[nIndex].m_pDNSFrame = this;
  89
  90 }
  91
  92 CDNSRecord* CDNSFrame::GetDnsRecord(int nIndex)
  93 {
  94     if (nIndex > m_nMaxItems)
  95         return NULL;
  96     return &m_dnsItems[nIndex];
  97 }
  98
  99 bool CDNSFrame::ParseDNSFrame(BJ_UINT8* pBuffer,BJ_INT32 nLength, BJ_UINT64 frameTime)
 100 {
 101     if (pBuffer == NULL)
 102         return false;
 103
 104     int nIndex = 0;
 105
 106     m_Servicev4Address.Empty();
 107     m_Servicev6Address.Empty();
 108
 109     m_pStartBuffer = pBuffer;
 110     m_nFrameLen = (BJ_UINT32) nLength;
 111
 112     m_pCurrentBuffer = m_pStartBuffer;
 113     m_pEndBuffer = m_pStartBuffer + m_nFrameLen;
 114     m_Time = frameTime;
 115
 116     m_nId = PF_GET_UINT16(m_pStartBuffer,0);
 117     m_nFlags = PF_GET_UINT16(m_pStartBuffer,2);
 118     m_nQuestionCount = PF_GET_UINT16(m_pStartBuffer,4);
 119     m_nAnswersCount = PF_GET_UINT16(m_pStartBuffer,6);
 120     m_NSCOUNT = PF_GET_UINT16(m_pStartBuffer,8);
 121     m_ARCOUNT = PF_GET_UINT16(m_pStartBuffer,10);
 122
 123     m_nMaxItems = 0;
 124
 125
 126
 127     // printf("FrameNum= %d,nQuestionCount= %d nAnswersCount= %d NSCOUNT= %d ARCOUNT= %d\n",nFrameCount++,m_nQuestionCount, m_nAnswersCount,m_NSCOUNT,  m_ARCOUNT);
 128
 129     m_pCurrentBuffer = m_pStartBuffer + 12;
 130
 131
 132     for (nIndex =0; nIndex < m_nQuestionCount;nIndex++)
 133     {
 134         //      printf("FramePosition= %ld  ",m_pCurrentBuffer);
 135         ParseDnsRecord(CDNSRecord::Question);
 136
 137     }
 138     for (nIndex =0; nIndex < m_nAnswersCount;nIndex++)
 139     {
 140         //      printf("FramePosition= %ld  ",m_pCurrentBuffer);
 141         ParseDnsRecord(CDNSRecord::Answer);
 142     }
 143     for (nIndex =0; nIndex < m_NSCOUNT;nIndex++)
 144     {
 145         //      printf("FramePosition= %ld  ",m_pCurrentBuffer);
 146         ParseDnsRecord(CDNSRecord::Answer);
 147     }
 148     for (nIndex =0; nIndex < m_ARCOUNT;nIndex++)
 149     {
 150         //      printf("FramePosition= %ld  ",m_pCurrentBuffer);
 151         ParseDnsRecord(CDNSRecord::Answer);
 152         CDNSRecord* pRecord =  &m_dnsItems[m_nMaxItems-1];
 153         if (pRecord->m_RecType == DNS_TYPE_AAAA && m_Servicev6Address.IsEmpty())
 154         {
 155             m_Servicev6Address.Setv6Raw(pRecord->GetStartofRdata());
 156         }
 157         if (pRecord->m_RecType == DNS_TYPE_A && m_Servicev4Address.IsEmpty())
 158         {
 159             m_Servicev4Address.Setv4Raw(pRecord->GetStartofRdata());
 160         }
 161     }
 162     //
 163     ///   for (dnsItemsIndex =0; dnsItemsIndex < m_nQuestionCount+m_nAnswersCount;dnsItemsIndex++)
 164     ///   {
 165     ///       printf("Name = %s\n", GetDnsRecordName(&Frame,dnsItemsIndex,tempBuffer,sizeof(tempBuffer)));
 166     //   }
 167     return true;
 168 }
 169
 170 BJ_BOOL CDNSFrame::ParseDnsRecord(CDNSRecord::dnsItemType eItemType)
 171 {
 172     unsigned char nCharCount = 0;
 173     BJ_UINT8* pTemp = m_pCurrentBuffer;
 174     CDNSRecord* pRecord =  &m_dnsItems[m_nMaxItems++];
 175
 176     //temp
 177     BJ_UINT16 nRdataLen = 0;
 178
 179     if (pTemp > m_pEndBuffer)
 180     {
 181         printf("Error in ParseDnsRecord pBuffer > pEndBuffer\n");
 182         pRecord->m_pStartofRec = NULL;
 183         pRecord->m_nNameLength = 0;
 184         return false;
 185     }
 186
 187
 188     pRecord->m_pStartofRec = pTemp;
 189     pRecord->m_nNameLength = 0;
 190     pRecord->m_nRdataLen = 0;
 191
 192
 193     // Skip over Name;
 194     while (pTemp < m_pEndBuffer)
 195     {
 196         nCharCount = *pTemp;
 197         pTemp++;
 198
 199         if (nCharCount == 0)
 200             break;
 201
 202         if ((nCharCount&(DNS_NAME_OFFSET_MASK)) == DNS_NAME_OFFSET_MASK)
 203         {  // offset string
 204             pTemp++;
 205             break;
 206         }
 207
 208         if (nCharCount > DNS_LABEL_MAX_LENGTH)
 209         {
 210             printf("%d. label too long %d\n",m_nMaxItems-1,nCharCount);
 211         }
 212
 213         if (pTemp + nCharCount < m_pEndBuffer)
 214             pTemp += nCharCount;
 215         else
 216             pTemp = m_pEndBuffer;
 217     }
 218
 219     pRecord->m_nNameLength = (BJ_UINT32)(pTemp - pRecord->m_pStartofRec);
 220
 221     if (eItemType == CDNSRecord::Question)
 222     {
 223         pRecord->m_RecType = PF_GET_UINT16(pTemp,0);
 224         pRecord->m_RecClass = PF_GET_UINT16(pTemp,2);
 225         pRecord->m_nTTL = PF_GET_UINT16(pTemp,4);
 226
 227         //   printf("Namelen=%u, Type=%u, class=%u, TTL=%u, RDLength=%u\n", m_dnsItems[ndnsIndex].nNameLength,nType,nClass,nTTL,nRdataLen);
 228
 229         pTemp += 4;
 230     }
 231     else
 232     {
 233
 234         pRecord->m_RecType = PF_GET_UINT16(pTemp,0);
 235         pRecord->m_RecClass = PF_GET_UINT16(pTemp,2);
 236
 237         pRecord->m_nTTL = PF_GET_UINT32(pTemp,4);
 238         pRecord->m_nRdataLen = PF_GET_UINT16(pTemp,8);
 239         if (nRdataLen > 1024*10)
 240         {
 241             printf("large Rdata ??");
 242         }
 243         //    printf("Namelen=%u, Type=%u, class=%u, TTL=%u, RDLength=%u\n", m_dnsItems[ndnsIndex].nNameLength,m_dnsItems[ndnsIndex].RecType,nClass,nTTL,m_dnsItems[ndnsIndex].nRdataLen);
 244         pTemp += 10 + pRecord->m_nRdataLen;
 245     }
 246
 247     m_pCurrentBuffer = pTemp;
 248
 249     return true;
 250 }
 251
 252 BJ_BOOL CDNSFrame::IsQueryFrame()
 253 {
 254     return !(m_nFlags&0x8000);
 255 }
 256
 257 #define UNICAST_RESPONDS_REQUESTED 0x8000
 258 BJ_BOOL CDNSFrame::IsWakeFrame()
 259 {
 260
 261     for (int i=0; i < m_nQuestionCount; i++)
 262     {
 263         if (m_dnsItems[i].m_RecType == DNS_TYPE_PTR &&  m_dnsItems[i].m_RecClass & UNICAST_RESPONDS_REQUESTED)
 264             return true;
 265     }
 266
 267     return false;
 268 }
 269 #define DNS_HEADER_TRUNCATEED 0x0200
 270 BJ_BOOL  CDNSFrame::IsTruncatedFrame()
 271 {
 272        return (m_nFlags&DNS_HEADER_TRUNCATEED);
 273 }
 274
 275
 276 BJ_BOOL CDNSFrame::HasOnlyService(BJString sName, BJ_INT16 nRecType)
 277 {
 278  /*   if (IsQueryFrame())
 279     {
 280         for (int i=0; i < m_nQuestionCount; i++)
 281         {
 282             CBJString sRecordName;
 283             m_dnsItems[i].GetDnsRecordName(sRecordName, 0);
 284             if (m_dnsItems[i].m_RecType != nRecType && nRecType != -1)
 285                 return false;
 286
 287             if (!sRecordName.Contains(sName.GetBuffer()))
 288                 return false;
 289         }
 290     }
 291     else*/
 292     {
 293         for (int i=0; i < m_nQuestionCount+m_nAnswersCount; i++)
 294         {
 295             BJString sRecordName;
 296             m_dnsItems[i].GetDnsRecordName(sRecordName, 0,99);
 297             if (m_dnsItems[i].m_RecType != nRecType && nRecType != -1)
 298                 return false;
 299
 300             if (!sRecordName.Contains(sName.GetBuffer()))
 301                 return false;
 302         }
 303
 304
 305     }
 306
 307
 308     return true;
 309 }
 310
 311 CDNSRecord* CDNSFrame::FindAdditionRecord(BJString& sName,BJ_INT16 nRecType)
 312 {
 313     for (int i = 0; i < m_nMaxItems; i++)
 314     {
 315         if (m_dnsItems[i].m_RecType != nRecType && nRecType != -1)
 316             continue;
 317         BJString sRecordName;
 318         m_dnsItems[i].GetDnsRecordName(sRecordName, 0,99);
 319         if (sRecordName == sName)
 320             return &m_dnsItems[i];
 321     }
 322     return NULL;
 323 }
 324
 325 void CDNSFrame::SetAddress(BJIPAddr *pSourceIPAddress,BJMACAddr *pSourceMACAddress)
 326 {
 327     m_SourceIPAddress = *pSourceIPAddress;
 328     m_SourceMACAddress = *pSourceMACAddress;
 329
 330
 331 }
 332
 333
 334 bool CDNSFrame::GetTracingInfo(BJ_UINT8 &platform, BJ_UINT32 &version, BJMACAddr &)
 335 {
 336     // Find OPT record
 337     for (int i = m_nQuestionCount + m_nAnswersCount + m_NSCOUNT; i < m_nMaxItems; i++)
 338     {
 339         if (m_dnsItems[i].m_RecType == DNS_TYPE_OPT)
 340         {
 341             BJ_UINT8* rdata = m_dnsItems[i].GetStartofRdata();
 342
 343             BJ_UINT8* rdataEnd = rdata +  m_dnsItems[i].m_nRdataLen;
 344
 345             while (rdata < rdataEnd)
 346             {
 347                 BJ_UINT16 type = PF_GET_UINT16(rdata,0);
 348                 BJ_UINT16 len = PF_GET_UINT16(rdata,2);
 349
 350                 if (type == DNS_EDNS0_TRACE)
 351                 {
 352                     platform = PF_GET_UINT8(rdata,4);
 353                     if (len == 3)   // EDNS field of length 3 <rdar://15101783>
 354                     {
 355                         version = static_cast<BJ_UINT32>(PF_GET_UINT16(rdata,5));
 356                     }
 357                     else if (len == 5) // EDNS field of length 5 <rdar://15235603>
 358                     {
 359                         version = static_cast<BJ_UINT32>(PF_GET_UINT32(rdata, 5));
 360                     }
 361                     else
 362                     {
 363                         return false;
 364                     }
 365                     return true;
 366                 }
 367
 368
 369                 rdata += sizeof(BJ_UINT16)*2 + len;
 370             }
 371
 372         }
 373     }
 374     return false;
 375
 376 }
 377
 378
 379
 380
 381