pdns.cxx

sloedgy open sip stack source code

PObject::Comparison PDNS::SRVRecord::Compare(const PObject & obj) const
{
  const SRVRecord * other = dynamic_cast<const SRVRecord *>(&obj);

  if (other == NULL)
    return LessThan;

  if (priority < other->priority)
    return LessThan;
  else if (priority > other->priority)
    return GreaterThan;

  if (weight < other->weight)
    return LessThan;
  else if (weight > other->weight)
    return GreaterThan;

  return EqualTo;
}

void PDNS::SRVRecord::PrintOn(ostream & strm) const
{
  strm << "host=" << hostName << ":" << port << "(" << hostAddress << "), "
       << "priority=" << priority << ", "
       << "weight=" << weight;
}

/////////////////////////////////////////////////

PDNS::SRVRecord * PDNS::SRVRecordList::HandleDNSRecord(PDNS_RECORD dnsRecord, PDNS_RECORD results)
{
  PDNS::SRVRecord * record = NULL;

  if (
      (dnsRecord->Flags.S.Section == DnsSectionAnswer) && 
      (dnsRecord->wType == DNS_TYPE_SRV) &&
      (strlen(dnsRecord->Data.SRV.pNameTarget) > 0) &&
      (strcmp(dnsRecord->Data.SRV.pNameTarget, ".") != 0)
      ) {
    record = new SRVRecord();
    record->hostName = PString(dnsRecord->Data.SRV.pNameTarget);
    record->port     = dnsRecord->Data.SRV.wPort;
    record->priority = dnsRecord->Data.SRV.wPriority;
    record->weight   = dnsRecord->Data.SRV.wWeight;

    // see if any A records match this hostname
    PDNS_RECORD aRecord = results;
    while (aRecord != NULL) {
      if ((dnsRecord->Flags.S.Section == DnsSectionAddtional) && (dnsRecord->wType == DNS_TYPE_A)) {
        record->hostAddress = PIPSocket::Address(dnsRecord->Data.A.IpAddress);
        break;
      }
      aRecord = aRecord->pNext;
    }

    // if no A record found, then get address the hard way
    if (aRecord == NULL)
      PIPSocket::GetHostAddress(record->hostName, record->hostAddress);
  }

  return record;
}

void PDNS::SRVRecordList::PrintOn(ostream & strm) const
{
  PINDEX i;
  for (i = 0; i < GetSize(); i++) 
    strm << (*this)[i] << endl;
}

PDNS::SRVRecord * PDNS::SRVRecordList::GetFirst()
{
  if (GetSize() == 0)
    return NULL;

  // create a list of all prioities, to save time
  priPos = 0;
  priList.SetSize(0);

  PINDEX i;
  if (GetSize() > 0) {
    priList.SetSize(1);
    WORD lastPri = (*this)[0].priority;
    priList[0] = lastPri;
    (*this)[0].used = FALSE;
    for (i = 1; i < GetSize(); i++) {
      (*this)[i].used = FALSE;
      if ((*this)[i].priority != lastPri) {
        priPos++;
        priList.SetSize(priPos);
        lastPri = (*this)[i].priority;
        priList[priPos] = lastPri;
      }
    }
  }
  
  priPos = 0;
  return GetNext();
}

PDNS::SRVRecord * PDNS::SRVRecordList::GetNext()
{
  if (priList.GetSize() == 0)
    return NULL;

  while (priPos < priList.GetSize()) {

    WORD currentPri = priList[priPos];

    // find first record at current priority
    PINDEX firstPos;
    for (firstPos = 0; (firstPos < GetSize()) && ((*this)[firstPos].priority != currentPri); firstPos++) 
      ;
    if (firstPos == GetSize())
      return NULL;

    // calculate total of all unused weights at this priority
    unsigned totalWeight = (*this)[firstPos].weight;
    PINDEX i = firstPos + 1;
    PINDEX count = 1;
    while (i < GetSize() && ((*this)[i].priority == currentPri)) {
      if (!(*this)[i].used) {
        totalWeight += (*this)[i].weight;
        count ++;
      }
      ++i;
    }

    // if no matches found, go to the next priority level
    if (count == 0) {
      priPos++;
      continue;
    }

    // selected the correct item
    if (totalWeight > 0) {
      unsigned targetWeight = PRandom::Number() % (totalWeight+1);
      totalWeight = 0;
      for (i = 0; i < GetSize() && ((*this)[i].priority == currentPri); i++) {
        if (!(*this)[i].used) {
          totalWeight += (*this)[i].weight;
          if (totalWeight >= targetWeight) {
            (*this)[i].used = TRUE;
            return &(*this)[i];
          }
        }
      }
    }

    // pick a random item at this priority
    PINDEX j = firstPos + ((count == 0) ? 0 : (PRandom::Number() % count) );
    count = 0;
    for (i = 0; i < GetSize() && ((*this)[i].priority == currentPri); i++) {
      if (!(*this)[i].used) {
        if (count == j) {
          (*this)[i].used = TRUE;
          return &(*this)[i];
        }
        count++;
      }
    }

    // go to the next priority level
    priPos++;
  }

  return NULL;
}

BOOL PDNS::GetSRVRecords(
  const PString & _service,
  const PString & type,
  const PString & domain,
  PDNS::SRVRecordList & recordList
)
{
  if (_service.IsEmpty())
    return FALSE;

  PStringStream service;
  if (_service[0] != '_')
    service << '_';

  service << _service << "._" << type << '.' << domain;

  return GetSRVRecords(service, recordList);
}

BOOL PDNS::LookupSRV(
           const PURL & url,
        const PString & service,
          PStringList & returnList)
{
  WORD defaultPort = url.GetPort();
  PIPSocketAddressAndPortVector info;

  if (!LookupSRV(url.GetHostName(), service, defaultPort, info)) {
    PTRACE(6,"DNS\tSRV Lookup Fail no domain " << url );
    return FALSE;
  }

  PString user = url.GetUserName();
  if (user.GetLength() > 0)
    user = user + "@";

  PIPSocketAddressAndPortVector::const_iterator r;
  for (r = info.begin(); r != info.end(); ++r) 
    returnList.AppendString(user + r->address.AsString() + ":" + PString(PString::Unsigned, r->port));

  return returnList.GetSize() != 0;;
}

BOOL PDNS::LookupSRV(
         const PString & domain,            ///< domain to lookup
         const PString & service,           ///< service to use
                    WORD defaultPort,       ///< default port to use
         PIPSocketAddressAndPortVector & addrList  ///< list of sockets and ports
)
{
  if (domain.GetLength() == 0) {
    PTRACE(6,"DNS\tSRV lookup failed - cannot resolve hostname " << domain);
    return FALSE;
  }

  PTRACE(6,"DNS\tSRV Lookup " << domain << " service " << service);

  PDNS::SRVRecordList srvRecords;
  PString srvLookupStr = service;
  if (srvLookupStr.Right(1) != ".")
    srvLookupStr += ".";
  srvLookupStr += domain;
  BOOL found = PDNS::GetRecords(srvLookupStr, srvRecords);
  if (found) {
    PTRACE(6,"DNS\tSRV Record found " << domain << " service " << service);
    PDNS::SRVRecord * recPtr = srvRecords.GetFirst();
    while (recPtr != NULL) {
      PIPSocketAddressAndPort addrAndPort;

      addrAndPort.address = recPtr->hostAddress;

      if (recPtr->port > 0)
        addrAndPort.port = recPtr->port;
      else
        addrAndPort.port = defaultPort;

      addrList.push_back(addrAndPort);

      recPtr = srvRecords.GetNext();
    }
  } 

  return found;
}

///////////////////////////////////////////////////////

PObject::Comparison PDNS::MXRecord::Compare(const PObject & obj) const
{
  const MXRecord * other = dynamic_cast<const MXRecord *>(&obj);
  if (other == NULL)
    return LessThan;

  if (preference < other->preference)
    return LessThan;
  else if (preference > other->preference)
    return GreaterThan;

  return EqualTo;
}

void PDNS::MXRecord::PrintOn(ostream & strm) const
{
  strm << "host=" << hostName << "(" << hostAddress << "), "
       << "preference=" << preference;
}

///////////////////////////////////////////////////////

PDNS::MXRecord * PDNS::MXRecordList::HandleDNSRecord(PDNS_RECORD dnsRecord, PDNS_RECORD results)
{
  MXRecord * record = NULL;

  if (
      (dnsRecord->Flags.S.Section == DnsSectionAnswer) &&
      (dnsRecord->wType == DNS_TYPE_MX) &&
      (strlen(dnsRecord->Data.MX.pNameExchange) > 0)
     ) {
    record = new MXRecord();
    record->hostName   = PString(dnsRecord->Data.MX.pNameExchange);
    record->preference = dnsRecord->Data.MX.wPreference;

    // see if any A records match this hostname
    PDNS_RECORD aRecord = results;
    while (aRecord != NULL) {
      if ((dnsRecord->Flags.S.Section == DnsSectionAddtional) && (dnsRecord->wType == DNS_TYPE_A)) {
        record->hostAddress = PIPSocket::Address(dnsRecord->Data.A.IpAddress);
        break;
      }
      aRecord = aRecord->pNext;
    }

    // if no A record found, then get address the hard way
    if (aRecord == NULL)
      PIPSocket::GetHostAddress(record->hostName, record->hostAddress);
  }

  return record;
}

void PDNS::MXRecordList::PrintOn(ostream & strm) const
{
  PINDEX i;
  for (i = 0; i < GetSize(); i++) 
    strm << (*this)[i] << endl;
}

PDNS::MXRecord * PDNS::MXRecordList::GetFirst()
{
  PINDEX i;
  for (i = 0; i < GetSize(); i++) 
    (*this)[i].used = FALSE;

  lastIndex = 0;

  return GetNext();
}

PDNS::MXRecord * PDNS::MXRecordList::GetNext()
{
  if (GetSize() == 0)
    return NULL;

  if (lastIndex >= GetSize())
    return NULL;

  return (PDNS::MXRecord *)GetAt(lastIndex++);
}

#endif // P_DNS


// End Of File ///////////////////////////////////////////////////////////////