| // |
| // DNSFrame.cpp |
| // TestTB |
| // |
| // Created by Terrin Eager on 9/26/12. |
| // |
| // |
| |
| #include "DNSFrame.h" |
| |
| #define DNS_LABEL_MAX_LENGTH 63 |
| #define DNS_NAME_MAX_LENGTH 255 |
| |
| void CDNSRecord::GetDnsRecordName(BJString& ReturnString,int nLabelToSkip,int nMaxLabel) |
| { |
| GetDnsRecordNameFromBuffer(m_pStartofRec, ReturnString, nLabelToSkip, nMaxLabel); |
| } |
| |
| void CDNSRecord::GetDnsRecordNameFromBuffer(BJ_UINT8* pBuffer,BJString& ReturnString,int nLabelToSkip,int nMaxLabel) |
| { |
| BJ_UINT8* pNameBuffer = NULL; |
| int nOffset = 0; |
| // char* pTemp = pReturnBuffer; |
| int nCharCount = 0; |
| int nSkippedLabels = 0; |
| int nLabelProcessed = 0; |
| ReturnString.Set(NULL,255); |
| |
| if (ReturnString.GetBuffer() == NULL) |
| return; |
| |
| pNameBuffer = pBuffer; |
| if (pNameBuffer == NULL) |
| { |
| return; |
| } |
| |
| while (ReturnString.GetBufferLength() < 1024) |
| { |
| nCharCount = *pNameBuffer++; |
| if (nCharCount == 0) |
| break; |
| |
| if ((nCharCount&(DNS_NAME_OFFSET_MASK)) == DNS_NAME_OFFSET_MASK) |
| { |
| nOffset = *pNameBuffer++; |
| nOffset |= (nCharCount&(~DNS_NAME_OFFSET_MASK)) << 8; |
| pNameBuffer = m_pDNSFrame->GetBuffer() + nOffset; |
| continue; |
| } |
| |
| if (nCharCount > DNS_LABEL_MAX_LENGTH) |
| { |
| printf("label too long %d\n",nCharCount); |
| break; |
| } |
| |
| if (ReturnString.GetLength() + nCharCount + 1 > DNS_NAME_MAX_LENGTH) // + 1 is for the '.' added later on |
| { |
| printf("Name exceeded limit allowed for DNS: %d\n", ReturnString.GetLength() + nCharCount + 1); |
| break; |
| } |
| |
| if (nLabelToSkip > nSkippedLabels) |
| { |
| nSkippedLabels++; |
| pNameBuffer += nCharCount; |
| continue; |
| } |
| ReturnString.Append((char*)pNameBuffer, nCharCount); |
| pNameBuffer+= nCharCount; |
| nLabelProcessed++; |
| |
| if (nLabelProcessed >= nMaxLabel) |
| return; |
| |
| ReturnString += "."; |
| } |
| } |
| |
| |
| |
| |
| CDNSFrame::CDNSFrame() |
| { |
| |
| for(int nIndex=0; nIndex < MAX_DNS_RECORDS_PER_FRAME; nIndex++) |
| m_dnsItems[nIndex].m_pDNSFrame = this; |
| |
| } |
| |
| CDNSRecord* CDNSFrame::GetDnsRecord(int nIndex) |
| { |
| if (nIndex > m_nMaxItems) |
| return NULL; |
| return &m_dnsItems[nIndex]; |
| } |
| |
| bool CDNSFrame::ParseDNSFrame(BJ_UINT8* pBuffer,BJ_INT32 nLength, BJ_UINT64 frameTime) |
| { |
| if (pBuffer == NULL) |
| return false; |
| |
| int nIndex = 0; |
| |
| m_Servicev4Address.Empty(); |
| m_Servicev6Address.Empty(); |
| |
| m_pStartBuffer = pBuffer; |
| m_nFrameLen = (BJ_UINT32) nLength; |
| |
| m_pCurrentBuffer = m_pStartBuffer; |
| m_pEndBuffer = m_pStartBuffer + m_nFrameLen; |
| m_Time = frameTime; |
| |
| m_nId = PF_GET_UINT16(m_pStartBuffer,0); |
| m_nFlags = PF_GET_UINT16(m_pStartBuffer,2); |
| m_nQuestionCount = PF_GET_UINT16(m_pStartBuffer,4); |
| m_nAnswersCount = PF_GET_UINT16(m_pStartBuffer,6); |
| m_NSCOUNT = PF_GET_UINT16(m_pStartBuffer,8); |
| m_ARCOUNT = PF_GET_UINT16(m_pStartBuffer,10); |
| |
| m_nMaxItems = 0; |
| |
| |
| |
| // printf("FrameNum= %d,nQuestionCount= %d nAnswersCount= %d NSCOUNT= %d ARCOUNT= %d\n",nFrameCount++,m_nQuestionCount, m_nAnswersCount,m_NSCOUNT, m_ARCOUNT); |
| |
| m_pCurrentBuffer = m_pStartBuffer + 12; |
| |
| |
| for (nIndex =0; nIndex < m_nQuestionCount;nIndex++) |
| { |
| // printf("FramePosition= %ld ",m_pCurrentBuffer); |
| ParseDnsRecord(CDNSRecord::Question); |
| |
| } |
| for (nIndex =0; nIndex < m_nAnswersCount;nIndex++) |
| { |
| // printf("FramePosition= %ld ",m_pCurrentBuffer); |
| ParseDnsRecord(CDNSRecord::Answer); |
| } |
| for (nIndex =0; nIndex < m_NSCOUNT;nIndex++) |
| { |
| // printf("FramePosition= %ld ",m_pCurrentBuffer); |
| ParseDnsRecord(CDNSRecord::Answer); |
| } |
| for (nIndex =0; nIndex < m_ARCOUNT;nIndex++) |
| { |
| // printf("FramePosition= %ld ",m_pCurrentBuffer); |
| ParseDnsRecord(CDNSRecord::Answer); |
| CDNSRecord* pRecord = &m_dnsItems[m_nMaxItems-1]; |
| if (pRecord->m_RecType == DNS_TYPE_AAAA && m_Servicev6Address.IsEmpty()) |
| { |
| m_Servicev6Address.Setv6Raw(pRecord->GetStartofRdata()); |
| } |
| if (pRecord->m_RecType == DNS_TYPE_A && m_Servicev4Address.IsEmpty()) |
| { |
| m_Servicev4Address.Setv4Raw(pRecord->GetStartofRdata()); |
| } |
| } |
| // |
| /// for (dnsItemsIndex =0; dnsItemsIndex < m_nQuestionCount+m_nAnswersCount;dnsItemsIndex++) |
| /// { |
| /// printf("Name = %s\n", GetDnsRecordName(&Frame,dnsItemsIndex,tempBuffer,sizeof(tempBuffer))); |
| // } |
| return true; |
| } |
| |
| BJ_BOOL CDNSFrame::ParseDnsRecord(CDNSRecord::dnsItemType eItemType) |
| { |
| unsigned char nCharCount = 0; |
| BJ_UINT8* pTemp = m_pCurrentBuffer; |
| CDNSRecord* pRecord = &m_dnsItems[m_nMaxItems++]; |
| |
| //temp |
| BJ_UINT16 nRdataLen = 0; |
| |
| if (pTemp > m_pEndBuffer) |
| { |
| printf("Error in ParseDnsRecord pBuffer > pEndBuffer\n"); |
| pRecord->m_pStartofRec = NULL; |
| pRecord->m_nNameLength = 0; |
| return false; |
| } |
| |
| |
| pRecord->m_pStartofRec = pTemp; |
| pRecord->m_nNameLength = 0; |
| pRecord->m_nRdataLen = 0; |
| |
| |
| // Skip over Name; |
| while (pTemp < m_pEndBuffer) |
| { |
| nCharCount = *pTemp; |
| pTemp++; |
| |
| if (nCharCount == 0) |
| break; |
| |
| if ((nCharCount&(DNS_NAME_OFFSET_MASK)) == DNS_NAME_OFFSET_MASK) |
| { // offset string |
| pTemp++; |
| break; |
| } |
| |
| if (nCharCount > DNS_LABEL_MAX_LENGTH) |
| { |
| printf("%d. label too long %d\n",m_nMaxItems-1,nCharCount); |
| } |
| |
| if (pTemp + nCharCount < m_pEndBuffer) |
| pTemp += nCharCount; |
| else |
| pTemp = m_pEndBuffer; |
| } |
| |
| pRecord->m_nNameLength = (BJ_UINT32)(pTemp - pRecord->m_pStartofRec); |
| |
| if (eItemType == CDNSRecord::Question) |
| { |
| pRecord->m_RecType = PF_GET_UINT16(pTemp,0); |
| pRecord->m_RecClass = PF_GET_UINT16(pTemp,2); |
| pRecord->m_nTTL = PF_GET_UINT16(pTemp,4); |
| |
| // printf("Namelen=%u, Type=%u, class=%u, TTL=%u, RDLength=%u\n", m_dnsItems[ndnsIndex].nNameLength,nType,nClass,nTTL,nRdataLen); |
| |
| pTemp += 4; |
| } |
| else |
| { |
| |
| pRecord->m_RecType = PF_GET_UINT16(pTemp,0); |
| pRecord->m_RecClass = PF_GET_UINT16(pTemp,2); |
| |
| pRecord->m_nTTL = PF_GET_UINT32(pTemp,4); |
| pRecord->m_nRdataLen = PF_GET_UINT16(pTemp,8); |
| if (nRdataLen > 1024*10) |
| { |
| printf("large Rdata ??"); |
| } |
| // 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); |
| pTemp += 10 + pRecord->m_nRdataLen; |
| } |
| |
| m_pCurrentBuffer = pTemp; |
| |
| return true; |
| } |
| |
| BJ_BOOL CDNSFrame::IsQueryFrame() |
| { |
| return !(m_nFlags&0x8000); |
| } |
| |
| #define UNICAST_RESPONDS_REQUESTED 0x8000 |
| BJ_BOOL CDNSFrame::IsWakeFrame() |
| { |
| |
| for (int i=0; i < m_nQuestionCount; i++) |
| { |
| if (m_dnsItems[i].m_RecType == DNS_TYPE_PTR && m_dnsItems[i].m_RecClass & UNICAST_RESPONDS_REQUESTED) |
| return true; |
| } |
| |
| return false; |
| } |
| #define DNS_HEADER_TRUNCATEED 0x0200 |
| BJ_BOOL CDNSFrame::IsTruncatedFrame() |
| { |
| return (m_nFlags&DNS_HEADER_TRUNCATEED); |
| } |
| |
| |
| BJ_BOOL CDNSFrame::HasOnlyService(BJString sName, BJ_INT16 nRecType) |
| { |
| /* if (IsQueryFrame()) |
| { |
| for (int i=0; i < m_nQuestionCount; i++) |
| { |
| CBJString sRecordName; |
| m_dnsItems[i].GetDnsRecordName(sRecordName, 0); |
| if (m_dnsItems[i].m_RecType != nRecType && nRecType != -1) |
| return false; |
| |
| if (!sRecordName.Contains(sName.GetBuffer())) |
| return false; |
| } |
| } |
| else*/ |
| { |
| for (int i=0; i < m_nQuestionCount+m_nAnswersCount; i++) |
| { |
| BJString sRecordName; |
| m_dnsItems[i].GetDnsRecordName(sRecordName, 0,99); |
| if (m_dnsItems[i].m_RecType != nRecType && nRecType != -1) |
| return false; |
| |
| if (!sRecordName.Contains(sName.GetBuffer())) |
| return false; |
| } |
| |
| |
| } |
| |
| |
| return true; |
| } |
| |
| CDNSRecord* CDNSFrame::FindAdditionRecord(BJString& sName,BJ_INT16 nRecType) |
| { |
| for (int i = 0; i < m_nMaxItems; i++) |
| { |
| if (m_dnsItems[i].m_RecType != nRecType && nRecType != -1) |
| continue; |
| BJString sRecordName; |
| m_dnsItems[i].GetDnsRecordName(sRecordName, 0,99); |
| if (sRecordName == sName) |
| return &m_dnsItems[i]; |
| } |
| return NULL; |
| } |
| |
| void CDNSFrame::SetAddress(BJIPAddr *pSourceIPAddress,BJMACAddr *pSourceMACAddress) |
| { |
| m_SourceIPAddress = *pSourceIPAddress; |
| m_SourceMACAddress = *pSourceMACAddress; |
| |
| |
| } |
| |
| |
| bool CDNSFrame::GetTracingInfo(BJ_UINT8 &platform, BJ_UINT32 &version, BJMACAddr &) |
| { |
| // Find OPT record |
| for (int i = m_nQuestionCount + m_nAnswersCount + m_NSCOUNT; i < m_nMaxItems; i++) |
| { |
| if (m_dnsItems[i].m_RecType == DNS_TYPE_OPT) |
| { |
| BJ_UINT8* rdata = m_dnsItems[i].GetStartofRdata(); |
| |
| BJ_UINT8* rdataEnd = rdata + m_dnsItems[i].m_nRdataLen; |
| |
| while (rdata < rdataEnd) |
| { |
| BJ_UINT16 type = PF_GET_UINT16(rdata,0); |
| BJ_UINT16 len = PF_GET_UINT16(rdata,2); |
| |
| if (type == DNS_EDNS0_TRACE) |
| { |
| platform = PF_GET_UINT8(rdata,4); |
| if (len == 3) // EDNS field of length 3 <rdar://15101783> |
| { |
| version = static_cast<BJ_UINT32>(PF_GET_UINT16(rdata,5)); |
| } |
| else if (len == 5) // EDNS field of length 5 <rdar://15235603> |
| { |
| version = static_cast<BJ_UINT32>(PF_GET_UINT32(rdata, 5)); |
| } |
| else |
| { |
| return false; |
| } |
| return true; |
| } |
| |
| |
| rdata += sizeof(BJ_UINT16)*2 + len; |
| } |
| |
| } |
| } |
| return false; |
| |
| } |
| |
| |
| |
| |
| |
