1 files changed, 158 insertions, 0 deletions
diff --git a/libs/minidns/src/main/java/de/measite/minidns/Question.java b/libs/minidns/src/main/java/de/measite/minidns/Question.java
new file mode 100644
index 00000000..3b2fa1a1
--- /dev/null
+++ b/libs/minidns/src/main/java/de/measite/minidns/Question.java
@@ -0,0 +1,158 @@
+package de.measite.minidns;
+
+import java.io.ByteArrayOutputStream;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.util.Arrays;
+
+import de.measite.minidns.Record.CLASS;
+import de.measite.minidns.Record.TYPE;
+import de.measite.minidns.util.NameUtil;
+
+/**
+ * A DNS question (request).
+ */
+public class Question {
+
+    /**
+     * The question string (e.g. "measite.de").
+     */
+    private final String name;
+
+    /**
+     * The question type (e.g. A).
+     */
+    private final TYPE type;
+
+    /**
+     * The question class (usually IN / internet).
+     */
+    private final CLASS clazz;
+
+    /**
+     * UnicastQueries have the highest bit of the CLASS field set to 1.
+     */
+    private final boolean unicastQuery;
+
+    /**
+     * Cache for the serialized object.
+     */
+    private byte[] byteArray;
+
+    /**
+     * Create a dns question for the given name/type/class.
+     * @param name The name e.g. "measite.de".
+     * @param type The type, e.g. A.
+     * @param clazz The class, usually IN (internet).
+     */
+    public Question(String name, TYPE type, CLASS clazz, boolean unicastQuery) {
+        this.name = name;
+        this.type = type;
+        this.clazz = clazz;
+        this.unicastQuery = unicastQuery;
+    }
+
+    /**
+     * Create a dns question for the given name/type/class.
+     * @param name The name e.g. "measite.de".
+     * @param type The type, e.g. A.
+     * @param clazz The class, usually IN (internet).
+     */
+    public Question(String name, TYPE type, CLASS clazz) {
+        this(name, type, clazz, false);
+    }
+
+    /**
+     * Create a dns question for the given name/type/IN (internet class).
+     * @param name The name e.g. "measite.de".
+     * @param type The type, e.g. A.
+     */
+    public Question(String name, TYPE type) {
+        this(name, type, CLASS.IN);
+    }
+
+    /**
+     * Retrieve the type of this question.
+     * @return The type.
+     */
+    public TYPE getType() {
+        return type;
+    }
+
+    /**
+     * Retrieve the class of this dns question (usually internet).
+     * @return The class of this dns question.
+     */
+    public CLASS getClazz() {
+        return clazz;
+    }
+
+    /**
+     * Retrieve the name of this dns question (e.g. "measite.de").
+     * @return The name of this dns question.
+     */
+    public String getName() {
+        return name;
+    }
+
+    /**
+     * Parse a byte array and rebuild the dns question from it.
+     * @param dis The input stream.
+     * @param data The plain data (for dns name references).
+     * @return The parsed dns question.
+     * @throws IOException On errors (read outside of packet).
+     */
+    public static Question parse(DataInputStream dis, byte[] data) throws IOException {
+        String name = NameUtil.parse(dis, data);
+        TYPE type = TYPE.getType(dis.readUnsignedShort());
+        CLASS clazz = CLASS.getClass(dis.readUnsignedShort());
+        return new Question (name, type, clazz);
+    }
+
+    /**
+     * Generate a binary paket for this dns question.
+     * @return The dns question.
+     */
+    public byte[] toByteArray() {
+        if (byteArray == null) {
+            ByteArrayOutputStream baos = new ByteArrayOutputStream(512);
+            DataOutputStream dos = new DataOutputStream(baos);
+
+            try {
+                dos.write(NameUtil.toByteArray(this.name));
+                dos.writeShort(type.getValue());
+                dos.writeShort(clazz.getValue() | (unicastQuery ? (1 << 15) : 0));
+                dos.flush();
+            } catch (IOException e) {
+                // Should never happen
+                throw new IllegalStateException(e);
+            }
+            byteArray = baos.toByteArray();
+        }
+        return byteArray;
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(toByteArray());
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (this == other) {
+            return true;
+        }
+        if (!(other instanceof Question)) {
+            return false;
+        }
+        byte t[] = toByteArray();
+        byte o[] = ((Question)other).toByteArray();
+        return Arrays.equals(t, o);
+    }
+
+    @Override
+    public String toString() {
+        return "Question/" + clazz + "/" + type + ": " + name;
+    }
+}