Updated comments from dns spec
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1 changed files with 152 additions and 56 deletions
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@ -29,13 +29,12 @@ import zutil.parser.binary.BinaryStruct.*;
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/**
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/**
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* Created by Ziver on 2016-02-09.
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* Created by Ziver on 2016-02-09.
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* Reference: http://tools.ietf.org/html/rfc1035
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*/
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*/
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public class DNSPacket implements BinaryStruct {
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public class DNSPacket implements BinaryStruct {
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public static final int OPCODE_QUERY = 0;
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public static final int OPCODE_QUERY = 0;
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public static final int OPCODE_IQUERY = 1;
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public static final int OPCODE_IQUERY = 1;
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public static final int OPCODE_STATUS = 2;
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public static final int OPCODE_STATUS = 2;
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public static final int OPCODE_NOTIFY = 4;
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public static final int OPCODE_UPDATE = 5;
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public static final int RCODE_NO_ERROR = 0;
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public static final int RCODE_NO_ERROR = 0;
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public static final int RCODE_FORMAT_ERROR = 1;
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public static final int RCODE_FORMAT_ERROR = 1;
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@ -43,11 +42,6 @@ public class DNSPacket implements BinaryStruct {
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public static final int RCODE_NAME_ERROR = 3;
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public static final int RCODE_NAME_ERROR = 3;
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public static final int RCODE_NOT_IMPLEMENTED = 4;
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public static final int RCODE_NOT_IMPLEMENTED = 4;
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public static final int RCODE_REFUSED = 5;
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public static final int RCODE_REFUSED = 5;
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public static final int RCODE_YX_DOMAIN = 6; // A name exists where it should not
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public static final int RCODE_YX_RR_SET = 7; // A resource record set exists where it should not
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public static final int RCODE_NX_RR_SET = 8; // A resource record set should exist but does not
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public static final int RCODE_NOT_AUTH = 9; // Server is not authoritative for the zone
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public static final int RCODE_NOT_ZONE = 10; // The name is not in the zone specified in the message
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@BinaryField(index=0, length=16)
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@BinaryField(index=0, length=16)
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@ -57,95 +51,197 @@ public class DNSPacket implements BinaryStruct {
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//@BinaryField(index=10, length=16)
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//@BinaryField(index=10, length=16)
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//int flags;
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//int flags;
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/**
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/**
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* Query/Response Flag.
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* A one bit field that specifies whether this message is a
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* Differentiates between queries and responses.
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* query (0), or a response (1).
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* Set to 0 when the query is generated; changed to 1 when that
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* query is changed to a response by a replying server.
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*/
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*/
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@BinaryField(index=10, length=1)
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@BinaryField(index=10, length=1)
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boolean qr;
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boolean flagQueryResponse;
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/**
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/**
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* Operation Code.
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* A four bit field that specifies kind of query in this message.
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* Specifies the type of query in the message. This field is
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* <pre>
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* copied unchanged in the response
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* 0 a standard query (QUERY)
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* 1 an inverse query (IQUERY)
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* 2 a server status request (STATUS)
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* </pre>
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*/
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*/
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@BinaryField(index=11, length=4)
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@BinaryField(index=11, length=4)
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int opcode;
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int flagOperationCode;
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/**
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/**
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* Authoritative Answer Flag
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* This bit is valid in responses,
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* This bit is set to true in a response to indicate that the server
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* and specifies that the responding name server is an
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* that created the response is authoritative for the zone in
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* authority for the domain name in question section.
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* which the domain name specified in the Question section is located
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*/
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*/
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@BinaryField(index=12, length=1)
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@BinaryField(index=12, length=1)
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boolean aa;
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boolean flagAuthoritativeAnswer;
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/**
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/**
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* Truncation Flag.
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* specifies that this message was truncated
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* When set to true, indicates that the message was truncated
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* due to length greater than that permitted on the
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* due to its length
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* transmission channel.
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*/
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*/
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@BinaryField(index=13, length=1)
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@BinaryField(index=13, length=1)
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boolean tc;
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boolean flagTruncation;
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/**
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/**
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* Recursion Desired.
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* this bit may be set in a query and
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* When set in a query, requests that the server receiving the
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* is copied into the response. If RD is set, it directs
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* query attempt to answer the query recursively, if the server
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* the name server to pursue the query recursively.
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* supports recursive resolution. The value of this bit is not
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* Recursive query support is optional.
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* changed in the response.
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*/
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*/
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@BinaryField(index=14, length=1)
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@BinaryField(index=14, length=1)
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boolean rd;
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boolean flagRecursionDesired;
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/**
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/**
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* Recursion Available.
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* this be is set or cleared in a
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* Set to true to indicate whether the server creating the response
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* response, and denotes whether recursive query support is
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* supports recursive queries.
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* available in the name server.
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*/
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*/
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@BinaryField(index=15, length=1)
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@BinaryField(index=15, length=1)
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boolean ra;
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boolean flagRecursionAvailable;
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@BinaryField(index=16, length=3)
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int reserved;
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/**
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/**
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* Response Code.
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* Reserved for future use. Must be zero in all queries
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* and responses.
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*/
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@BinaryField(index=16, length=3)
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private int z;
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/**
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* this field is set as part of responses.
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* The values have the following interpretation:
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* <pre>
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* 0 No error condition
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* 1 Format error - The name server was
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* unable to interpret the query.
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* 2 Server failure - The name server was
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* unable to process this query due to a
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* problem with the name server.
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* 3 Name Error - Meaningful only for
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* responses from an authoritative name
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* server, this code signifies that the
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* domain name referenced in the query does
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* not exist.
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* 4 Not Implemented - The name server does
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* not support the requested kind of query.
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* 5 Refused - The name server refuses to
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* perform the specified operation for
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* policy reasons.
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*</pre>
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*/
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*/
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@BinaryField(index=17, length=4)
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@BinaryField(index=17, length=4)
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int rCode;
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int flagResponseCode;
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//////////////// COUNTS
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//////////////// COUNTS
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/**
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/**
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* Question Count.
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* Question Count.
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* Specifies the number of questions in the
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* Specifying the number of entries in the question section.
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* Question section of the message.
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*/
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*/
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@BinaryField(index=20, length=16)
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@BinaryField(index=20, length=16)
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int qdCount;
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int countQuestion;
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/**
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/**
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* Answer Record Count.
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* Answer Record Count.
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* Specifies the number of resource records
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* specifying the number of resource records in
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* in the Answer section of the message.
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* the answer section.
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*/
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*/
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@BinaryField(index=21, length=16)
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@BinaryField(index=21, length=16)
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int anCount;
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int countAnswerRecord;
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/**
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/**
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* Name Server (Authority Record) Count.
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* Name Server (Authority Record) Count.
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* Specifies the number of resource records in the
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* Specifying the number of name server resource records
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* Authority section of the message.
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* in the authority records section.
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*/
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*/
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@BinaryField(index=22, length=16)
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@BinaryField(index=22, length=16)
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int nsCount;
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int countNameServer;
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/**
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/**
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* Additional Record Count.
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* Additional Record Count.
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* Specifies the number of resource records in the
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* Specifying the number of resource records in the
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* Additional section of the message.
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* additional records section
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*/
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*/
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@BinaryField(index=23, length=16)
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@BinaryField(index=23, length=16)
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int arCount;
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int countAdditionalRecord;
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//////////////// REQUEST DATA
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/*
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// char data[?]
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Question section format
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// char flag[2] => QTYPE=0x00_01 host address query
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1 1 1 1 1 1
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// QCLASS=0x00_01 internet query
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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/ QNAME /
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/ /
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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| QTYPE |
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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| QCLASS |
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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where:
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QNAME a domain name represented as a sequence of labels, where
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each label consists of a length octet followed by that
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number of octets. The domain name terminates with the
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zero length octet for the null label of the root. Note
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that this field may be an odd number of octets; no
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padding is used.
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QTYPE a two octet code which specifies the type of the query.
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The values for this field include all codes valid for a
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TYPE field, together with some more general codes which
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can match more than one type of RR.
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QCLASS a two octet code that specifies the class of the query.
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For example, the QCLASS field is IN for the Internet.
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*/
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/*
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Resource record format
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The answer, authority, and additional sections all share the same
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format: a variable number of resource records, where the number of
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records is specified in the corresponding count field in the header.
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Each resource record has the following format:
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1 1 1 1 1 1
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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/ /
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/ NAME /
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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| TYPE |
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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| CLASS |
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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| TTL |
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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| RDLENGTH |
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
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/ RDATA /
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/ /
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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where:
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NAME a domain name to which this resource record pertains.
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TYPE two octets containing one of the RR type codes. This
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field specifies the meaning of the data in the RDATA
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field.
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CLASS two octets which specify the class of the data in the
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RDATA field.
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TTL a 32 bit unsigned integer that specifies the time
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interval (in seconds) that the resource record may be
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cached before it should be discarded. Zero values are
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interpreted to mean that the RR can only be used for the
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transaction in progress, and should not be cached.
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RDLENGTH an unsigned 16 bit integer that specifies the length in
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octets of the RDATA field.
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RDATA a variable length string of octets that describes the
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resource. The format of this information varies
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according to the TYPE and CLASS of the resource record.
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For example, the if the TYPE is A and the CLASS is IN,
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the RDATA field is a 4 octet ARPA Internet address.
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*/
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}
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}
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