1 files changed, 286 insertions, 0 deletions
diff --git a/src/org/xbill/DNS/Header.java b/src/org/xbill/DNS/Header.java
new file mode 100644
index 0000000..2a44d08
--- /dev/null
+++ b/src/org/xbill/DNS/Header.java
@@ -0,0 +1,286 @@
+// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)
+
+package org.xbill.DNS;
+
+import java.io.*;
+import java.util.*;
+
+/**
+ * A DNS message header
+ * @see Message
+ *
+ * @author Brian Wellington
+ */
+
+public class Header implements Cloneable {
+
+private int id; 
+private int flags;
+private int [] counts;
+
+private static Random random = new Random();
+
+/** The length of a DNS Header in wire format. */
+public static final int LENGTH = 12;
+
+private void
+init() {
+	counts = new int[4];
+	flags = 0;
+	id = -1;
+}
+
+/**
+ * Create a new empty header.
+ * @param id The message id
+ */
+public
+Header(int id) {
+	init();
+	setID(id);
+}
+
+/**
+ * Create a new empty header with a random message id
+ */
+public
+Header() {
+	init();
+}
+
+/**
+ * Parses a Header from a stream containing DNS wire format.
+ */
+Header(DNSInput in) throws IOException {
+	this(in.readU16());
+	flags = in.readU16();
+	for (int i = 0; i < counts.length; i++)
+		counts[i] = in.readU16();
+}
+
+/**
+ * Creates a new Header from its DNS wire format representation
+ * @param b A byte array containing the DNS Header.
+ */
+public
+Header(byte [] b) throws IOException {
+	this(new DNSInput(b));
+}
+
+void
+toWire(DNSOutput out) {
+	out.writeU16(getID());
+	out.writeU16(flags);
+	for (int i = 0; i < counts.length; i++)
+		out.writeU16(counts[i]);
+}
+
+public byte []
+toWire() {
+	DNSOutput out = new DNSOutput();
+	toWire(out);
+	return out.toByteArray();
+}
+
+static private boolean
+validFlag(int bit) {
+	return (bit >= 0 && bit <= 0xF && Flags.isFlag(bit));
+}
+
+static private void
+checkFlag(int bit) {
+	if (!validFlag(bit))
+		throw new IllegalArgumentException("invalid flag bit " + bit);
+}
+
+/**
+ * Sets a flag to the supplied value
+ * @see Flags
+ */
+public void
+setFlag(int bit) {
+	checkFlag(bit);
+	// bits are indexed from left to right
+	flags |= (1 << (15 - bit));
+}
+
+/**
+ * Sets a flag to the supplied value
+ * @see Flags
+ */
+public void
+unsetFlag(int bit) {
+	checkFlag(bit);
+	// bits are indexed from left to right
+	flags &= ~(1 << (15 - bit));
+}
+
+/**
+ * Retrieves a flag
+ * @see Flags
+ */
+public boolean
+getFlag(int bit) {
+	checkFlag(bit);
+	// bits are indexed from left to right
+	return (flags & (1 << (15 - bit))) != 0;
+}
+
+boolean []
+getFlags() {
+	boolean [] array = new boolean[16];
+	for (int i = 0; i < array.length; i++)
+		if (validFlag(i))
+			array[i] = getFlag(i);
+	return array;
+}
+
+/**
+ * Retrieves the message ID
+ */
+public int
+getID() {
+	if (id >= 0)
+		return id;
+	synchronized (this) {
+		if (id < 0)
+			id = random.nextInt(0xffff);
+		return id;
+	}
+}
+
+/**
+ * Sets the message ID
+ */
+public void
+setID(int id) {
+	if (id < 0 || id > 0xffff)
+		throw new IllegalArgumentException("DNS message ID " + id +
+						   " is out of range");
+	this.id = id;
+}
+
+/**
+ * Sets the message's rcode
+ * @see Rcode
+ */
+public void
+setRcode(int value) {
+	if (value < 0 || value > 0xF)
+		throw new IllegalArgumentException("DNS Rcode " + value +
+						   " is out of range");
+	flags &= ~0xF;
+	flags |= value;
+}
+
+/**
+ * Retrieves the mesasge's rcode
+ * @see Rcode
+ */
+public int
+getRcode() {
+	return flags & 0xF;
+}
+
+/**
+ * Sets the message's opcode
+ * @see Opcode
+ */
+public void
+setOpcode(int value) {
+	if (value < 0 || value > 0xF)
+		throw new IllegalArgumentException("DNS Opcode " + value +
+						   "is out of range");
+	flags &= 0x87FF;
+	flags |= (value << 11);
+}
+
+/**
+ * Retrieves the mesasge's opcode
+ * @see Opcode
+ */
+public int
+getOpcode() {
+	return (flags >> 11) & 0xF;
+}
+
+void
+setCount(int field, int value) {
+	if (value < 0 || value > 0xFFFF)
+		throw new IllegalArgumentException("DNS section count " +
+						   value + " is out of range");
+	counts[field] = value;
+}
+
+void
+incCount(int field) {
+	if (counts[field] == 0xFFFF)
+		throw new IllegalStateException("DNS section count cannot " +
+						"be incremented");
+	counts[field]++;
+}
+
+void
+decCount(int field) {
+	if (counts[field] == 0)
+		throw new IllegalStateException("DNS section count cannot " +
+						"be decremented");
+	counts[field]--;
+}
+
+/**
+ * Retrieves the record count for the given section
+ * @see Section
+ */
+public int
+getCount(int field) {
+	return counts[field];
+}
+
+/** Converts the header's flags into a String */
+public String
+printFlags() {
+	StringBuffer sb = new StringBuffer();
+
+	for (int i = 0; i < 16; i++)
+		if (validFlag(i) && getFlag(i)) {
+			sb.append(Flags.string(i));
+			sb.append(" ");
+		}
+	return sb.toString();
+}
+
+String
+toStringWithRcode(int newrcode) {
+	StringBuffer sb = new StringBuffer();
+
+	sb.append(";; ->>HEADER<<- "); 
+	sb.append("opcode: " + Opcode.string(getOpcode()));
+	sb.append(", status: " + Rcode.string(newrcode));
+	sb.append(", id: " + getID());
+	sb.append("\n");
+
+	sb.append(";; flags: " + printFlags());
+	sb.append("; ");
+	for (int i = 0; i < 4; i++)
+		sb.append(Section.string(i) + ": " + getCount(i) + " ");
+	return sb.toString();
+}
+
+/** Converts the header into a String */
+public String
+toString() {
+	return toStringWithRcode(getRcode());
+}
+
+/* Creates a new Header identical to the current one */
+public Object
+clone() {
+	Header h = new Header();
+	h.id = id;
+	h.flags = flags;
+	System.arraycopy(counts, 0, h.counts, 0, counts.length);
+	return h;
+}
+
+}