/**
<summary>Creates a response given the entire packet.</summary>
<remarks>The entire packet must be given, because some name servers take
advantage of pointers to reduce their size.</remarks>
<param name="Data">The entire DNS packet.</param>
<param name="Start">The starting position of the Response.</param>
*/
public Response(MemBlock Data, int Start)
{
int idx = 0;
NAME_BLOB = DNSPacket.RetrieveBlob(Data, Start, out idx);
int type = (Data[idx++] << 8) + Data[idx++];
TYPE = (DNSPacket.TYPES) type;
CACHE_FLUSH = ((Data[idx] & 0x80) == 0x80) ? true : false;
int rclass = ((Data[idx++] << 8) & 0x7F) + Data[idx++];
CLASS = (DNSPacket.CLASSES) rclass;
TTL = (Data[idx++] << 24);
TTL |= (Data[idx++] << 16);
TTL |= (Data[idx++] << 8);
TTL |= (Data[idx++]);
RDLENGTH = (short) ((Data[idx++] << 8) + Data[idx++]);
RDATA_BLOB = Data.Slice(idx, RDLENGTH);
if(TYPE == DNSPacket.TYPES.PTR) {
try {
NAME = DNSPacket.PtrMemBlockToString(NAME_BLOB);
}
catch {
NAME = DNSPacket.HostnameMemBlockToString(NAME_BLOB);
}
int End = 0;
RDATA_BLOB = DNSPacket.RetrieveBlob(Data, idx, out End);
RDATA = DNSPacket.HostnameMemBlockToString(RDATA_BLOB);
}
else if(TYPE == DNSPacket.TYPES.A) {
NAME = DNSPacket.HostnameMemBlockToString(NAME_BLOB);
RDATA = DNSPacket.IPMemBlockToString(RDATA_BLOB);
}
_icpacket = _packet = Data.Slice(Start, idx + RDLENGTH - Start);
}
/**
<summary>Constructor when creating a DNS Query</summary>
<param name="QNAME">the name of resource you are looking up, IP Address
when QTYPE = PTR otherwise hostname</param>
<param name="QTYPE"> the type of look up to perform</param>
<param name="QCLASS">should always be IN</param>
*/
public Question(String QNAME, DNSPacket.TYPES QTYPE, DNSPacket.CLASSES QCLASS)
{
this.QNAME = QNAME;
this.QTYPE = QTYPE;
this.QCLASS = QCLASS;
if(QTYPE == DNSPacket.TYPES.A) {
QNAME_BLOB = DNSPacket.HostnameStringToMemBlock(QNAME);
}
else if(QTYPE == DNSPacket.TYPES.PTR) {
QNAME_BLOB = DNSPacket.PtrStringToMemBlock(QNAME);
}
else {
throw new Exception("Invalid QTYPE: " + QTYPE + "!");
}
// 2 for QTYPE + 2 for QCLASS
byte[] data = new byte[4];
int idx = 0;
data[idx++] = (byte) ((((int) QTYPE) >> 8) & 0xFF);
data[idx++] = (byte) (((int) QTYPE) & 0xFF);
data[idx++] = (byte) ((((int) QCLASS) >> 8) & 0xFF);
data[idx++] = (byte) (((int) QCLASS) & 0xFF);
_icpacket = new CopyList(QNAME_BLOB, MemBlock.Reference(data));
}
/**
<summary>Creates a response from the parameter fields with RDATA being
a memory chunk. This is for MDNS which supports caching</summary>
<param name="NAME">The name resolved.</param>
<param name="TYPE">The query type.</param>
<param name="CLASS">The network type.</param>
<param name="CACHE_FLUSH">Flush the dns cache in the client.</param>
<param name="TTL">How long to hold the result in the local dns cache.</param>
<param name="RDATA">RDATA in String format.</param>
*/
public Response(String NAME, DNSPacket.TYPES TYPE, DNSPacket.CLASSES CLASS,
bool CACHE_FLUSH, int TTL, String RDATA)
{
this.NAME = NAME;
this.CLASS = CLASS;
this.TTL = TTL;
this.TYPE = TYPE;
this.CLASS = CLASS;
this.CACHE_FLUSH = CACHE_FLUSH;
this.RDATA = RDATA;
if(TYPE == DNSPacket.TYPES.A) {
NAME_BLOB = DNSPacket.HostnameStringToMemBlock(NAME);
RDATA_BLOB = DNSPacket.IPStringToMemBlock(RDATA);
}
else if(TYPE == DNSPacket.TYPES.PTR) {
if(DNSPacket.StringIsIP(NAME)) {
NAME_BLOB = DNSPacket.PtrStringToMemBlock(NAME);
}
else {
NAME_BLOB = DNSPacket.HostnameStringToMemBlock(NAME);
}
RDATA_BLOB = DNSPacket.HostnameStringToMemBlock(RDATA);
}
else {
throw new Exception("Invalid Query TYPE: " + TYPE + "!");
}
RDLENGTH = (short) RDATA_BLOB.Length;
// 2 for TYPE + 2 for CLASS + 4 for TTL + 2 for RDLENGTH
byte[] data = new byte[10];
int idx = 0;
data[idx++] = (byte) ((((int) TYPE) >> 8) & 0xFF);
data[idx++] = (byte) (((int) TYPE) & 0xFF);
byte cache_flush = 0x80;
if(!CACHE_FLUSH) {
cache_flush = 0x00;
}
data[idx++] = (byte) (((((int) CLASS) >> 8) & 0x7F) | cache_flush);
data[idx++] = (byte) (((int) CLASS) & 0xFF);
data[idx++] = (byte) ((TTL >> 24) & 0xFF);
data[idx++] = (byte) ((TTL >> 16) & 0xFF);
data[idx++] = (byte) ((TTL >> 8) & 0xFF);
data[idx++] = (byte) (TTL & 0xFF);
data[idx++] = (byte) ((RDLENGTH >> 8) & 0xFF);
data[idx] = (byte) (RDLENGTH & 0xFF);
_icpacket = new CopyList(NAME_BLOB, MemBlock.Reference(data), RDATA_BLOB);
}
/**
<summary>Constructor when parsing a DNS Query</summary>
<param name="Data"> must pass in the entire packet from where the question
begins, after parsing, can check Data.Length to find where next
container begins.</param>
*/
public Question(MemBlock Data, int Start)
{
int idx = 0;
QNAME_BLOB = DNSPacket.RetrieveBlob(Data, Start, out idx);
int qtype = (Data[idx++] << 8) + Data[idx++];
QTYPE = (DNSPacket.TYPES) qtype;
int qclass = (Data[idx++] << 8) + Data[idx];
QCLASS = (DNSPacket.CLASSES) qclass;
if(QTYPE == DNSPacket.TYPES.A) {
QNAME = DNSPacket.HostnameMemBlockToString(QNAME_BLOB);
}
else if(QTYPE == DNSPacket.TYPES.PTR) {
QNAME = DNSPacket.PtrMemBlockToString(QNAME_BLOB);
}
_icpacket = _packet = Data.Slice(Start, idx + 1 - Start);
}
