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1 files changed, 293 insertions, 0 deletions

diff --git a/src/de/measite/minidns/Record.java b/src/de/measite/minidns/Record.java
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+package de.measite.minidns;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.util.HashMap;
+
+import de.measite.minidns.record.A;
+import de.measite.minidns.record.AAAA;
+import de.measite.minidns.record.CNAME;
+import de.measite.minidns.record.Data;
+import de.measite.minidns.record.NS;
+import de.measite.minidns.record.SRV;
+import de.measite.minidns.util.NameUtil;
+
+/**
+ * A generic DNS record.
+ */
+public class Record {
+
+    /**
+     * The record type.
+     * {@see http://www.iana.org/assignments/dns-parameters}
+     */
+    public static enum TYPE {
+        A(1),
+        NS(2),
+        MD(3),
+        MF(4),
+        CNAME(5),
+        SOA(6),
+        MB(7),
+        MG(8),
+        MR(9),
+        NULL(10),
+        WKS(11),
+        PTR(12),
+        HINFO(13),
+        MINFO(14),
+        MX(15),
+        TXT(16),
+        RP(17),
+        AFSDB(18),
+        X25(19),
+        ISDN(20),
+        RT(21),
+        NSAP(22),
+        NSAP_PTR(23),
+        SIG(24),
+        KEY(25),
+        PX(26),
+        GPOS(27),
+        AAAA(28),
+        LOC(29),
+        NXT(30),
+        EID(31),
+        NIMLOC(32),
+        SRV(33),
+        ATMA(34),
+        NAPTR(35),
+        KX(36),
+        CERT(37),
+        A6(38),
+        DNAME(39),
+        SINK(40),
+        OPT(41),
+        APL(42),
+        DS(43),
+        SSHFP(44),
+        IPSECKEY(45),
+        RRSIG(46),
+        NSEC(47),
+        DNSKEY(48),
+        DHCID(49),
+        NSEC3(50),
+        NSEC3PARAM(51),
+        HIP(55),
+        NINFO(56),
+        RKEY(57),
+        TALINK(58),
+        SPF(99),
+        UINFO(100),
+        UID(101),
+        GID(102),
+        TKEY(249),
+        TSIG(250),
+        IXFR(251),
+        AXFR(252),
+        MAILB(253),
+        MAILA(254),
+        ANY(255),
+        TA(32768),
+        DLV(32769);
+
+        /**
+         * The value of this DNS record type.
+         */
+        private final int value;
+
+        /**
+         * Internal lookup table to map values to types.
+         */
+        private final static HashMap<Integer, TYPE> INVERSE_LUT =
+                                        new HashMap<Integer, TYPE>();
+
+        /**
+         * Initialize the reverse lookup table.
+         */
+        static {
+            for(TYPE t: TYPE.values()) {
+                INVERSE_LUT.put(t.getValue(), t);
+            }
+        }
+
+        /**
+         * Create a new record type.
+         * @param value The binary value of this type.
+         */
+        private TYPE(int value) {
+            this.value = value;
+        }
+
+        /**
+         * Retrieve the binary value of this type.
+         * @return The binary value.
+         */
+        public int getValue() {
+            return value;
+        }
+
+        /**
+         * Retrieve the symbolic type of the binary value.
+         * @param value The binary type value.
+         * @return The symbolic tpye.
+         */
+        public static TYPE getType(int value) {
+            return INVERSE_LUT.get(value);
+        }
+    };
+
+    /**
+     * The symbolic class of a DNS record (usually IN for Internet).
+     */
+    public static enum CLASS {
+        IN(1),
+        CH(3),
+        HS(4),
+        NONE(254),
+        ANY(255);
+
+        /**
+         * Internal reverse lookup table to map binary class values to symbolic
+         * names.
+         */
+        private final static HashMap<Integer, CLASS> INVERSE_LUT =
+                                            new HashMap<Integer, CLASS>();
+
+        /**
+         * Initialize the interal reverse lookup table.
+         */
+        static {
+            for(CLASS c: CLASS.values()) {
+                INVERSE_LUT.put(c.getValue(), c);
+            }
+        }
+
+        /**
+         * The binary value of this dns class.
+         */
+        private final int value;
+
+        /**
+         * Create a new DNS class based on a binary value.
+         * @param value The binary value of this DNS class.
+         */
+        private CLASS(int value) {
+            this.value = value;
+        }
+
+        /**
+         * Retrieve the binary value of this DNS class.
+         * @return The binary value of this DNS class.
+         */
+        public int getValue() {
+            return value;
+        }
+
+        /**
+         * Retrieve the symbolic DNS class for a binary class value.
+         * @param value The binary DNS class value.
+         * @return The symbolic class instance.
+         */
+        public static CLASS getClass(int value) {
+            return INVERSE_LUT.get(value);
+        }
+
+    }
+
+    /**
+     * The generic name of this record.
+     */
+    protected String name;
+
+    /**
+     * The type (and payload type) of this record.
+     */
+    protected TYPE type;
+
+    /**
+     * The record class (usually CLASS.IN).
+     */
+    protected CLASS clazz;
+
+    /**
+     * The ttl of this record.
+     */
+    protected long ttl;
+
+    /**
+     * The payload object of this record.
+     */
+    protected Data payloadData;
+
+    /**
+     * Parse a given record based on the full message data and the current
+     * stream position.
+     * @param dis The DataInputStream positioned at the first record byte.
+     * @param data The full message data.
+     * @throws IOException In case of malformed replies.
+     */
+    public void parse(DataInputStream dis, byte[] data) throws IOException {
+        this.name = NameUtil.parse(dis, data);
+        this.type = TYPE.getType(dis.readUnsignedShort());
+        this.clazz = CLASS.getClass(dis.readUnsignedShort());
+        this.ttl = (((long)dis.readUnsignedShort()) << 32) +
+                   dis.readUnsignedShort();
+        int payloadLength = dis.readUnsignedShort();
+        switch (this.type) {
+        case SRV:
+            this.payloadData = new SRV();
+            break;
+        case AAAA:
+            this.payloadData = new AAAA();
+            break;
+        case A:
+            this.payloadData = new A();
+            break;
+        case NS:
+            this.payloadData = new NS();
+            break;
+        case CNAME:
+            this.payloadData = new CNAME();
+            break;
+        default:
+            System.out.println("Unparsed type " + type);
+            this.payloadData = null;
+            for (int i = 0; i < payloadLength; i++) {
+                dis.readByte();
+            }
+            break;
+        }
+        if (this.payloadData != null) {
+            this.payloadData.parse(dis, data, payloadLength);
+        }
+    }
+
+    /**
+     * Retrieve a textual representation of this resource record.
+     * @return String
+     */
+    @Override
+    public String toString() {
+        if (payloadData == null) {
+            return "RR " + type + "/" + clazz;
+        }
+        return "RR " + type + "/" + clazz + ": " + payloadData.toString();
+    };
+
+    /**
+     * Check if this record answers a given query.
+     * @param q The query.
+     * @return True if this record is a valid answer.
+     */
+    public boolean isAnswer(Question q) {
+        return ((q.getType() == type) || (q.getType() == TYPE.ANY)) &&
+               ((q.getClazz() == clazz) || (q.getClazz() == CLASS.ANY)) &&
+               (q.getName().equals(name));
+    }
+
+    public Data getPayload() {
+        return payloadData;
+    }
+
+}