/// <summary> Generate a possibly unique name for a host using the information we
/// have in the cache.
///
/// </summary>
/// <returns> returns true, if the name of the host had to be changed.
/// </returns>
private bool MakeHostNameUnique(Address host)
{
string originalName = host.Name;
long now = (DateTime.Now.Ticks - 621355968000000000) / 10000;
bool collision;
do
{
collision = false;
// Check for collision in cache
for (DNSCache.CacheNode j = cache.find(host.Name.ToLower()); j != null; j = j.Next)
{
DNSRecord a = (DNSRecord) j.Value;
if (false) // TODO: huh?
{
host.name = IncrementName(host.Name);
collision = true;
break;
}
}
}
while (collision);
if (originalName.Equals(host.Name))
{
return false;
}
else
{
return true;
}
}
internal virtual Address GetDNSAddressRecord(Address address)
{
return (DNSConstants.TYPE_AAAA == address.type?DNS6AddressRecord:DNS4AddressRecord);
}
/// <summary> Does a lexicographic comparison of the byte array representation
/// of this record and that record.
/// This is needed for tie-break tests according to
/// draft-cheshire-dnsext-multicastdns-04.txt chapter 9.2.
/// </summary>
private int lexCompare(Address that)
{
sbyte[] thisBytes = this.toByteArray();
sbyte[] thatBytes = that.toByteArray();
for (int i = 0, n = Math.Min(thisBytes.Length, thatBytes.Length); i < n; i++)
{
if (thisBytes[i] > thatBytes[i])
{
return 1;
}
else if (thisBytes[i] < thatBytes[i])
{
return - 1;
}
}
return thisBytes.Length - thatBytes.Length;
}
/// <summary> Parse a message from a datagram packet.</summary>
internal DNSIncoming(SupportClass.PacketSupport packet)
{
this.packet = packet;
this.data = SupportClass.ToSByteArray(packet.Data);
this.len = packet.Length;
// TODO: will this always be 0 in .NET??
this.off = 0;
this.questions = ArrayList.ReadOnly(new ArrayList());
this.answers = ArrayList.ReadOnly(new ArrayList());
this.receivedTime = (DateTime.Now.Ticks - 621355968000000000) / 10000;
try
{
id = ReadUnsignedShort();
flags = ReadUnsignedShort();
numQuestions = ReadUnsignedShort();
numAnswers = ReadUnsignedShort();
numAuthorities = ReadUnsignedShort();
numAdditionals = ReadUnsignedShort();
// parse questions
if (numQuestions > 0)
{
questions = ArrayList.Synchronized(new ArrayList(numQuestions));
for (int i = 0; i < numQuestions; i++)
{
DNSQuestion question = new DNSQuestion(ReadName(), ReadUnsignedShort(), ReadUnsignedShort());
questions.Add(question);
}
}
// parse answers
int n = numAnswers + numAuthorities + numAdditionals;
if (n > 0)
{
answers = ArrayList.Synchronized(new ArrayList(n));
for (int i = 0; i < n; i++)
{
string domain = ReadName();
int type = ReadUnsignedShort();
int clazz = ReadUnsignedShort();
int ttl = ReadInt();
int len = ReadUnsignedShort();
int end = off + len;
DNSRecord rec = null;
switch (type)
{
case DNSConstants.TYPE_A:
// IPv4
case DNSConstants.TYPE_AAAA: // IPv6 FIXME [PJYF Oct 14 2004] This has not been tested
rec = new Address(domain, type, clazz, ttl, ReadBytes(off, len));
break;
case DNSConstants.TYPE_CNAME:
case DNSConstants.TYPE_PTR:
rec = new Pointer(domain, type, clazz, ttl, ReadName());
break;
case DNSConstants.TYPE_TXT:
rec = new Text(domain, type, clazz, ttl, ReadBytes(off, len));
break;
case DNSConstants.TYPE_SRV:
rec = new Service(domain, type, clazz, ttl, ReadUnsignedShort(), ReadUnsignedShort(), ReadUnsignedShort(), ReadName());
break;
case DNSConstants.TYPE_HINFO:
// Maybe we should do something with those
break;
default:
logger.Debug("DNSIncoming() unknown type:" + type);
break;
}
if (rec != null)
{
// Add a record, if we were able to create one.
answers.Add(rec);
}
else
{
// Addjust the numbers for the skipped record
if (answers.Count < numAnswers)
{
numAnswers--;
}
else if (answers.Count < numAnswers + numAuthorities)
{
numAuthorities--;
}
else if (answers.Count < numAnswers + numAuthorities + numAdditionals)
{
numAdditionals--;
}
}
off = end;
}
}
}
catch (IOException e)
{
logger.Warn("DNSIncoming() dump " + Print(true) + "\n exception ", e);
throw e;
}
}