1 files changed, 81 insertions, 0 deletions
diff --git a/src/org/xbill/DNS/Flags.java b/src/org/xbill/DNS/Flags.java
new file mode 100644
index 0000000..964ce23
--- /dev/null
+++ b/src/org/xbill/DNS/Flags.java
@@ -0,0 +1,81 @@
+// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)
+
+package org.xbill.DNS;
+
+/**
+ * Constants and functions relating to flags in the DNS header.
+ *
+ * @author Brian Wellington
+ */
+
+public final class Flags {
+
+private static Mnemonic flags = new Mnemonic("DNS Header Flag",
+					     Mnemonic.CASE_LOWER);
+
+/** query/response */
+public static final byte QR		= 0;
+
+/** authoritative answer */
+public static final byte AA		= 5;
+
+/** truncated */
+public static final byte TC		= 6;
+
+/** recursion desired */
+public static final byte RD		= 7;
+
+/** recursion available */
+public static final byte RA		= 8;
+
+/** authenticated data */
+public static final byte AD		= 10;
+
+/** (security) checking disabled */
+public static final byte CD		= 11;
+
+/** dnssec ok (extended) */
+public static final int DO		= ExtendedFlags.DO;
+
+static {
+	flags.setMaximum(0xF);
+	flags.setPrefix("FLAG");
+	flags.setNumericAllowed(true);
+
+	flags.add(QR, "qr");
+	flags.add(AA, "aa");
+	flags.add(TC, "tc");
+	flags.add(RD, "rd");
+	flags.add(RA, "ra");
+	flags.add(AD, "ad");
+	flags.add(CD, "cd");
+}
+
+private
+Flags() {}
+
+/** Converts a numeric Flag into a String */
+public static String
+string(int i) {
+	return flags.getText(i);
+}
+
+/** Converts a String representation of an Flag into its numeric value */
+public static int
+value(String s) {
+	return flags.getValue(s);
+}
+
+/**
+ * Indicates if a bit in the flags field is a flag or not.  If it's part of
+ * the rcode or opcode, it's not.
+ */
+public static boolean
+isFlag(int index) {
+	flags.check(index);
+	if ((index >= 1 && index <= 4) || (index >= 12))
+		return false;
+	return true;
+}
+
+}