Initial import

.gitignore

@@ -0,0 +1,3 @@
+/nbproject/private/
+/build
+/dist

build.xml

@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- You may freely edit this file. See commented blocks below for -->
+<!-- some examples of how to customize the build. -->
+<!-- (If you delete it and reopen the project it will be recreated.) -->
+<!-- By default, only the Clean and Build commands use this build script. -->
+<!-- Commands such as Run, Debug, and Test only use this build script if -->
+<!-- the Compile on Save feature is turned off for the project. -->
+<!-- You can turn off the Compile on Save (or Deploy on Save) setting -->
+<!-- in the project's Project Properties dialog box.-->
+<project name="NatTraversal" default="default" basedir=".">
+    <description>Builds, tests, and runs the project NatTraversal.</description>
+    <import file="nbproject/build-impl.xml"/>
+    <!--
+
+    There exist several targets which are by default empty and which can be 
+    used for execution of your tasks. These targets are usually executed 
+    before and after some main targets. They are: 
+
+      -pre-init:                 called before initialization of project properties
+      -post-init:                called after initialization of project properties
+      -pre-compile:              called before javac compilation
+      -post-compile:             called after javac compilation
+      -pre-compile-single:       called before javac compilation of single file
+      -post-compile-single:      called after javac compilation of single file
+      -pre-compile-test:         called before javac compilation of JUnit tests
+      -post-compile-test:        called after javac compilation of JUnit tests
+      -pre-compile-test-single:  called before javac compilation of single JUnit test
+      -post-compile-test-single: called after javac compilation of single JUunit test
+      -pre-jar:                  called before JAR building
+      -post-jar:                 called after JAR building
+      -post-clean:               called after cleaning build products
+
+    (Targets beginning with '-' are not intended to be called on their own.)
+
+    Example of inserting an obfuscator after compilation could look like this:
+
+        <target name="-post-compile">
+            <obfuscate>
+                <fileset dir="${build.classes.dir}"/>
+            </obfuscate>
+        </target>
+
+    For list of available properties check the imported 
+    nbproject/build-impl.xml file. 
+
+
+    Another way to customize the build is by overriding existing main targets.
+    The targets of interest are: 
+
+      -init-macrodef-javac:     defines macro for javac compilation
+      -init-macrodef-junit:     defines macro for junit execution
+      -init-macrodef-debug:     defines macro for class debugging
+      -init-macrodef-java:      defines macro for class execution
+      -do-jar-with-manifest:    JAR building (if you are using a manifest)
+      -do-jar-without-manifest: JAR building (if you are not using a manifest)
+      run:                      execution of project 
+      -javadoc-build:           Javadoc generation
+      test-report:              JUnit report generation
+
+    An example of overriding the target for project execution could look like this:
+
+        <target name="run" depends="NatTraversal-impl.jar">
+            <exec dir="bin" executable="launcher.exe">
+                <arg file="${dist.jar}"/>
+            </exec>
+        </target>
+
+    Notice that the overridden target depends on the jar target and not only on 
+    the compile target as the regular run target does. Again, for a list of available 
+    properties which you can use, check the target you are overriding in the
+    nbproject/build-impl.xml file. 
+
+    -->
+</project>

nbproject/build-impl.xml

@@ -0,0 +1,805 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+*** GENERATED FROM project.xml - DO NOT EDIT  ***
+***         EDIT ../build.xml INSTEAD         ***
+
+For the purpose of easier reading the script
+is divided into following sections:
+
+  - initialization
+  - compilation
+  - jar
+  - execution
+  - debugging
+  - javadoc
+  - junit compilation
+  - junit execution
+  - junit debugging
+  - applet
+  - cleanup
+
+        -->
+<project xmlns:j2seproject1="http://www.netbeans.org/ns/j2se-project/1" xmlns:j2seproject3="http://www.netbeans.org/ns/j2se-project/3" xmlns:jaxrpc="http://www.netbeans.org/ns/j2se-project/jax-rpc" basedir=".." default="default" name="NatTraversal-impl">
+    <fail message="Please build using Ant 1.7.1 or higher.">
+        <condition>
+            <not>
+                <antversion atleast="1.7.1"/>
+            </not>
+        </condition>
+    </fail>
+    <target depends="test,jar,javadoc" description="Build and test whole project." name="default"/>
+    <!-- 
+                ======================
+                INITIALIZATION SECTION 
+                ======================
+            -->
+    <target name="-pre-init">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="-pre-init" name="-init-private">
+        <property file="nbproject/private/config.properties"/>
+        <property file="nbproject/private/configs/${config}.properties"/>
+        <property file="nbproject/private/private.properties"/>
+    </target>
+    <target depends="-pre-init,-init-private" name="-init-user">
+        <property file="${user.properties.file}"/>
+        <!-- The two properties below are usually overridden -->
+        <!-- by the active platform. Just a fallback. -->
+        <property name="default.javac.source" value="1.4"/>
+        <property name="default.javac.target" value="1.4"/>
+    </target>
+    <target depends="-pre-init,-init-private,-init-user" name="-init-project">
+        <property file="nbproject/configs/${config}.properties"/>
+        <property file="nbproject/project.properties"/>
+    </target>
+    <target depends="-pre-init,-init-private,-init-user,-init-project,-init-macrodef-property" name="-do-init">
+        <available file="${manifest.file}" property="manifest.available"/>
+        <condition property="main.class.available">
+            <and>
+                <isset property="main.class"/>
+                <not>
+                    <equals arg1="${main.class}" arg2="" trim="true"/>
+                </not>
+            </and>
+        </condition>
+        <condition property="manifest.available+main.class">
+            <and>
+                <isset property="manifest.available"/>
+                <isset property="main.class.available"/>
+            </and>
+        </condition>
+        <condition property="do.mkdist">
+            <and>
+                <isset property="libs.CopyLibs.classpath"/>
+                <not>
+                    <istrue value="${mkdist.disabled}"/>
+                </not>
+            </and>
+        </condition>
+        <condition property="manifest.available+main.class+mkdist.available">
+            <and>
+                <istrue value="${manifest.available+main.class}"/>
+                <isset property="do.mkdist"/>
+            </and>
+        </condition>
+        <condition property="manifest.available+mkdist.available">
+            <and>
+                <istrue value="${manifest.available}"/>
+                <isset property="do.mkdist"/>
+            </and>
+        </condition>
+        <condition property="manifest.available-mkdist.available">
+            <or>
+                <istrue value="${manifest.available}"/>
+                <isset property="do.mkdist"/>
+            </or>
+        </condition>
+        <condition property="manifest.available+main.class-mkdist.available">
+            <or>
+                <istrue value="${manifest.available+main.class}"/>
+                <isset property="do.mkdist"/>
+            </or>
+        </condition>
+        <condition property="have.tests">
+            <or>
+                <available file="${test.src.dir}"/>
+            </or>
+        </condition>
+        <condition property="have.sources">
+            <or>
+                <available file="${src.dir}"/>
+            </or>
+        </condition>
+        <condition property="netbeans.home+have.tests">
+            <and>
+                <isset property="netbeans.home"/>
+                <isset property="have.tests"/>
+            </and>
+        </condition>
+        <condition property="no.javadoc.preview">
+            <and>
+                <isset property="javadoc.preview"/>
+                <isfalse value="${javadoc.preview}"/>
+            </and>
+        </condition>
+        <property name="run.jvmargs" value=""/>
+        <property name="javac.compilerargs" value=""/>
+        <property name="work.dir" value="${basedir}"/>
+        <condition property="no.deps">
+            <and>
+                <istrue value="${no.dependencies}"/>
+            </and>
+        </condition>
+        <property name="javac.debug" value="true"/>
+        <property name="javadoc.preview" value="true"/>
+        <property name="application.args" value=""/>
+        <property name="source.encoding" value="${file.encoding}"/>
+        <property name="runtime.encoding" value="${source.encoding}"/>
+        <condition property="javadoc.encoding.used" value="${javadoc.encoding}">
+            <and>
+                <isset property="javadoc.encoding"/>
+                <not>
+                    <equals arg1="${javadoc.encoding}" arg2=""/>
+                </not>
+            </and>
+        </condition>
+        <property name="javadoc.encoding.used" value="${source.encoding}"/>
+        <property name="includes" value="**"/>
+        <property name="excludes" value=""/>
+        <property name="do.depend" value="false"/>
+        <condition property="do.depend.true">
+            <istrue value="${do.depend}"/>
+        </condition>
+        <path id="endorsed.classpath.path" path="${endorsed.classpath}"/>
+        <condition else="" property="endorsed.classpath.cmd.line.arg" value="-Xbootclasspath/p:'${toString:endorsed.classpath.path}'">
+            <length length="0" string="${endorsed.classpath}" when="greater"/>
+        </condition>
+        <property name="javac.fork" value="false"/>
+    </target>
+    <target name="-post-init">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="-pre-init,-init-private,-init-user,-init-project,-do-init" name="-init-check">
+        <fail unless="src.dir">Must set src.dir</fail>
+        <fail unless="test.src.dir">Must set test.src.dir</fail>
+        <fail unless="build.dir">Must set build.dir</fail>
+        <fail unless="dist.dir">Must set dist.dir</fail>
+        <fail unless="build.classes.dir">Must set build.classes.dir</fail>
+        <fail unless="dist.javadoc.dir">Must set dist.javadoc.dir</fail>
+        <fail unless="build.test.classes.dir">Must set build.test.classes.dir</fail>
+        <fail unless="build.test.results.dir">Must set build.test.results.dir</fail>
+        <fail unless="build.classes.excludes">Must set build.classes.excludes</fail>
+        <fail unless="dist.jar">Must set dist.jar</fail>
+    </target>
+    <target name="-init-macrodef-property">
+        <macrodef name="property" uri="http://www.netbeans.org/ns/j2se-project/1">
+            <attribute name="name"/>
+            <attribute name="value"/>
+            <sequential>
+                <property name="@{name}" value="${@{value}}"/>
+            </sequential>
+        </macrodef>
+    </target>
+    <target name="-init-macrodef-javac">
+        <macrodef name="javac" uri="http://www.netbeans.org/ns/j2se-project/3">
+            <attribute default="${src.dir}" name="srcdir"/>
+            <attribute default="${build.classes.dir}" name="destdir"/>
+            <attribute default="${javac.classpath}" name="classpath"/>
+            <attribute default="${includes}" name="includes"/>
+            <attribute default="${excludes}" name="excludes"/>
+            <attribute default="${javac.debug}" name="debug"/>
+            <attribute default="${empty.dir}" name="sourcepath"/>
+            <attribute default="${empty.dir}" name="gensrcdir"/>
+            <element name="customize" optional="true"/>
+            <sequential>
+                <property location="${build.dir}/empty" name="empty.dir"/>
+                <mkdir dir="${empty.dir}"/>
+                <javac debug="@{debug}" deprecation="${javac.deprecation}" destdir="@{destdir}" encoding="${source.encoding}" excludes="@{excludes}" fork="${javac.fork}" includeantruntime="false" includes="@{includes}" source="${javac.source}" sourcepath="@{sourcepath}" srcdir="@{srcdir}" target="${javac.target}" tempdir="${java.io.tmpdir}">
+                    <src>
+                        <dirset dir="@{gensrcdir}" erroronmissingdir="false">
+                            <include name="*"/>
+                        </dirset>
+                    </src>
+                    <classpath>
+                        <path path="@{classpath}"/>
+                    </classpath>
+                    <compilerarg line="${endorsed.classpath.cmd.line.arg}"/>
+                    <compilerarg line="${javac.compilerargs}"/>
+                    <customize/>
+                </javac>
+            </sequential>
+        </macrodef>
+        <macrodef name="depend" uri="http://www.netbeans.org/ns/j2se-project/3">
+            <attribute default="${src.dir}" name="srcdir"/>
+            <attribute default="${build.classes.dir}" name="destdir"/>
+            <attribute default="${javac.classpath}" name="classpath"/>
+            <sequential>
+                <depend cache="${build.dir}/depcache" destdir="@{destdir}" excludes="${excludes}" includes="${includes}" srcdir="@{srcdir}">
+                    <classpath>
+                        <path path="@{classpath}"/>
+                    </classpath>
+                </depend>
+            </sequential>
+        </macrodef>
+        <macrodef name="force-recompile" uri="http://www.netbeans.org/ns/j2se-project/3">
+            <attribute default="${build.classes.dir}" name="destdir"/>
+            <sequential>
+                <fail unless="javac.includes">Must set javac.includes</fail>
+                <pathconvert pathsep="," property="javac.includes.binary">
+                    <path>
+                        <filelist dir="@{destdir}" files="${javac.includes}"/>
+                    </path>
+                    <globmapper from="*.java" to="*.class"/>
+                </pathconvert>
+                <delete>
+                    <files includes="${javac.includes.binary}"/>
+                </delete>
+            </sequential>
+        </macrodef>
+    </target>
+    <target name="-init-macrodef-junit">
+        <macrodef name="junit" uri="http://www.netbeans.org/ns/j2se-project/3">
+            <attribute default="${includes}" name="includes"/>
+            <attribute default="${excludes}" name="excludes"/>
+            <attribute default="**" name="testincludes"/>
+            <sequential>
+                <junit dir="${work.dir}" errorproperty="tests.failed" failureproperty="tests.failed" fork="true" showoutput="true" tempdir="${build.dir}">
+                    <batchtest todir="${build.test.results.dir}">
+                        <fileset dir="${test.src.dir}" excludes="@{excludes},${excludes}" includes="@{includes}">
+                            <filename name="@{testincludes}"/>
+                        </fileset>
+                    </batchtest>
+                    <classpath>
+                        <path path="${run.test.classpath}"/>
+                    </classpath>
+                    <syspropertyset>
+                        <propertyref prefix="test-sys-prop."/>
+                        <mapper from="test-sys-prop.*" to="*" type="glob"/>
+                    </syspropertyset>
+                    <formatter type="brief" usefile="false"/>
+                    <formatter type="xml"/>
+                    <jvmarg line="${endorsed.classpath.cmd.line.arg}"/>
+                    <jvmarg line="${run.jvmargs}"/>
+                </junit>
+            </sequential>
+        </macrodef>
+    </target>
+    <target depends="-init-debug-args" name="-init-macrodef-nbjpda">
+        <macrodef name="nbjpdastart" uri="http://www.netbeans.org/ns/j2se-project/1">
+            <attribute default="${main.class}" name="name"/>
+            <attribute default="${debug.classpath}" name="classpath"/>
+            <attribute default="" name="stopclassname"/>
+            <sequential>
+                <nbjpdastart addressproperty="jpda.address" name="@{name}" stopclassname="@{stopclassname}" transport="${debug-transport}">
+                    <classpath>
+                        <path path="@{classpath}"/>
+                    </classpath>
+                </nbjpdastart>
+            </sequential>
+        </macrodef>
+        <macrodef name="nbjpdareload" uri="http://www.netbeans.org/ns/j2se-project/1">
+            <attribute default="${build.classes.dir}" name="dir"/>
+            <sequential>
+                <nbjpdareload>
+                    <fileset dir="@{dir}" includes="${fix.classes}">
+                        <include name="${fix.includes}*.class"/>
+                    </fileset>
+                </nbjpdareload>
+            </sequential>
+        </macrodef>
+    </target>
+    <target name="-init-debug-args">
+        <property name="version-output" value="java version &quot;${ant.java.version}"/>
+        <condition property="have-jdk-older-than-1.4">
+            <or>
+                <contains string="${version-output}" substring="java version &quot;1.0"/>
+                <contains string="${version-output}" substring="java version &quot;1.1"/>
+                <contains string="${version-output}" substring="java version &quot;1.2"/>
+                <contains string="${version-output}" substring="java version &quot;1.3"/>
+            </or>
+        </condition>
+        <condition else="-Xdebug" property="debug-args-line" value="-Xdebug -Xnoagent -Djava.compiler=none">
+            <istrue value="${have-jdk-older-than-1.4}"/>
+        </condition>
+        <condition else="dt_socket" property="debug-transport-by-os" value="dt_shmem">
+            <os family="windows"/>
+        </condition>
+        <condition else="${debug-transport-by-os}" property="debug-transport" value="${debug.transport}">
+            <isset property="debug.transport"/>
+        </condition>
+    </target>
+    <target depends="-init-debug-args" name="-init-macrodef-debug">
+        <macrodef name="debug" uri="http://www.netbeans.org/ns/j2se-project/3">
+            <attribute default="${main.class}" name="classname"/>
+            <attribute default="${debug.classpath}" name="classpath"/>
+            <element name="customize" optional="true"/>
+            <sequential>
+                <java classname="@{classname}" dir="${work.dir}" fork="true">
+                    <jvmarg line="${endorsed.classpath.cmd.line.arg}"/>
+                    <jvmarg line="${debug-args-line}"/>
+                    <jvmarg value="-Xrunjdwp:transport=${debug-transport},address=${jpda.address}"/>
+                    <jvmarg value="-Dfile.encoding=${runtime.encoding}"/>
+                    <redirector errorencoding="${runtime.encoding}" inputencoding="${runtime.encoding}" outputencoding="${runtime.encoding}"/>
+                    <jvmarg line="${run.jvmargs}"/>
+                    <classpath>
+                        <path path="@{classpath}"/>
+                    </classpath>
+                    <syspropertyset>
+                        <propertyref prefix="run-sys-prop."/>
+                        <mapper from="run-sys-prop.*" to="*" type="glob"/>
+                    </syspropertyset>
+                    <customize/>
+                </java>
+            </sequential>
+        </macrodef>
+    </target>
+    <target name="-init-macrodef-java">
+        <macrodef name="java" uri="http://www.netbeans.org/ns/j2se-project/1">
+            <attribute default="${main.class}" name="classname"/>
+            <attribute default="${run.classpath}" name="classpath"/>
+            <element name="customize" optional="true"/>
+            <sequential>
+                <java classname="@{classname}" dir="${work.dir}" fork="true">
+                    <jvmarg line="${endorsed.classpath.cmd.line.arg}"/>
+                    <jvmarg value="-Dfile.encoding=${runtime.encoding}"/>
+                    <redirector errorencoding="${runtime.encoding}" inputencoding="${runtime.encoding}" outputencoding="${runtime.encoding}"/>
+                    <jvmarg line="${run.jvmargs}"/>
+                    <classpath>
+                        <path path="@{classpath}"/>
+                    </classpath>
+                    <syspropertyset>
+                        <propertyref prefix="run-sys-prop."/>
+                        <mapper from="run-sys-prop.*" to="*" type="glob"/>
+                    </syspropertyset>
+                    <customize/>
+                </java>
+            </sequential>
+        </macrodef>
+    </target>
+    <target name="-init-presetdef-jar">
+        <presetdef name="jar" uri="http://www.netbeans.org/ns/j2se-project/1">
+            <jar compress="${jar.compress}" jarfile="${dist.jar}">
+                <j2seproject1:fileset dir="${build.classes.dir}"/>
+            </jar>
+        </presetdef>
+    </target>
+    <target depends="-pre-init,-init-private,-init-user,-init-project,-do-init,-post-init,-init-check,-init-macrodef-property,-init-macrodef-javac,-init-macrodef-junit,-init-macrodef-nbjpda,-init-macrodef-debug,-init-macrodef-java,-init-presetdef-jar" name="init"/>
+    <!--
+                ===================
+                COMPILATION SECTION
+                ===================
+            -->
+    <target name="-deps-jar-init" unless="built-jar.properties">
+        <property location="${build.dir}/built-jar.properties" name="built-jar.properties"/>
+        <delete file="${built-jar.properties}" quiet="true"/>
+    </target>
+    <target if="already.built.jar.${basedir}" name="-warn-already-built-jar">
+        <echo level="warn" message="Cycle detected: NatTraversal was already built"/>
+    </target>
+    <target depends="init,-deps-jar-init" name="deps-jar" unless="no.deps">
+        <mkdir dir="${build.dir}"/>
+        <touch file="${built-jar.properties}" verbose="false"/>
+        <property file="${built-jar.properties}" prefix="already.built.jar."/>
+        <antcall target="-warn-already-built-jar"/>
+        <propertyfile file="${built-jar.properties}">
+            <entry key="${basedir}" value=""/>
+        </propertyfile>
+    </target>
+    <target depends="init,-check-automatic-build,-clean-after-automatic-build" name="-verify-automatic-build"/>
+    <target depends="init" name="-check-automatic-build">
+        <available file="${build.classes.dir}/.netbeans_automatic_build" property="netbeans.automatic.build"/>
+    </target>
+    <target depends="init" if="netbeans.automatic.build" name="-clean-after-automatic-build">
+        <antcall target="clean"/>
+    </target>
+    <target depends="init,deps-jar" name="-pre-pre-compile">
+        <mkdir dir="${build.classes.dir}"/>
+    </target>
+    <target name="-pre-compile">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target if="do.depend.true" name="-compile-depend">
+        <pathconvert property="build.generated.subdirs">
+            <dirset dir="${build.generated.sources.dir}" erroronmissingdir="false">
+                <include name="*"/>
+            </dirset>
+        </pathconvert>
+        <j2seproject3:depend srcdir="${src.dir}:${build.generated.subdirs}"/>
+    </target>
+    <target depends="init,deps-jar,-pre-pre-compile,-pre-compile,-compile-depend" if="have.sources" name="-do-compile">
+        <j2seproject3:javac gensrcdir="${build.generated.sources.dir}"/>
+        <copy todir="${build.classes.dir}">
+            <fileset dir="${src.dir}" excludes="${build.classes.excludes},${excludes}" includes="${includes}"/>
+        </copy>
+    </target>
+    <target name="-post-compile">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,deps-jar,-verify-automatic-build,-pre-pre-compile,-pre-compile,-do-compile,-post-compile" description="Compile project." name="compile"/>
+    <target name="-pre-compile-single">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,deps-jar,-pre-pre-compile" name="-do-compile-single">
+        <fail unless="javac.includes">Must select some files in the IDE or set javac.includes</fail>
+        <j2seproject3:force-recompile/>
+        <j2seproject3:javac excludes="" gensrcdir="${build.generated.sources.dir}" includes="${javac.includes}" sourcepath="${src.dir}"/>
+    </target>
+    <target name="-post-compile-single">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,deps-jar,-verify-automatic-build,-pre-pre-compile,-pre-compile-single,-do-compile-single,-post-compile-single" name="compile-single"/>
+    <!--
+                ====================
+                JAR BUILDING SECTION
+                ====================
+            -->
+    <target depends="init" name="-pre-pre-jar">
+        <dirname file="${dist.jar}" property="dist.jar.dir"/>
+        <mkdir dir="${dist.jar.dir}"/>
+    </target>
+    <target name="-pre-jar">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,compile,-pre-pre-jar,-pre-jar" name="-do-jar-without-manifest" unless="manifest.available-mkdist.available">
+        <j2seproject1:jar/>
+    </target>
+    <target depends="init,compile,-pre-pre-jar,-pre-jar" if="manifest.available" name="-do-jar-with-manifest" unless="manifest.available+main.class-mkdist.available">
+        <j2seproject1:jar manifest="${manifest.file}"/>
+    </target>
+    <target depends="init,compile,-pre-pre-jar,-pre-jar" if="manifest.available+main.class" name="-do-jar-with-mainclass" unless="manifest.available+main.class+mkdist.available">
+        <j2seproject1:jar manifest="${manifest.file}">
+            <j2seproject1:manifest>
+                <j2seproject1:attribute name="Main-Class" value="${main.class}"/>
+            </j2seproject1:manifest>
+        </j2seproject1:jar>
+        <echo>To run this application from the command line without Ant, try:</echo>
+        <property location="${build.classes.dir}" name="build.classes.dir.resolved"/>
+        <property location="${dist.jar}" name="dist.jar.resolved"/>
+        <pathconvert property="run.classpath.with.dist.jar">
+            <path path="${run.classpath}"/>
+            <map from="${build.classes.dir.resolved}" to="${dist.jar.resolved}"/>
+        </pathconvert>
+        <echo>java -cp "${run.classpath.with.dist.jar}" ${main.class}</echo>
+    </target>
+    <target depends="init,compile,-pre-pre-jar,-pre-jar" if="manifest.available+main.class+mkdist.available" name="-do-jar-with-libraries">
+        <property location="${build.classes.dir}" name="build.classes.dir.resolved"/>
+        <pathconvert property="run.classpath.without.build.classes.dir">
+            <path path="${run.classpath}"/>
+            <map from="${build.classes.dir.resolved}" to=""/>
+        </pathconvert>
+        <pathconvert pathsep=" " property="jar.classpath">
+            <path path="${run.classpath.without.build.classes.dir}"/>
+            <chainedmapper>
+                <flattenmapper/>
+                <globmapper from="*" to="lib/*"/>
+            </chainedmapper>
+        </pathconvert>
+        <taskdef classname="org.netbeans.modules.java.j2seproject.copylibstask.CopyLibs" classpath="${libs.CopyLibs.classpath}" name="copylibs"/>
+        <copylibs compress="${jar.compress}" jarfile="${dist.jar}" manifest="${manifest.file}" runtimeclasspath="${run.classpath.without.build.classes.dir}">
+            <fileset dir="${build.classes.dir}"/>
+            <manifest>
+                <attribute name="Main-Class" value="${main.class}"/>
+                <attribute name="Class-Path" value="${jar.classpath}"/>
+            </manifest>
+        </copylibs>
+        <echo>To run this application from the command line without Ant, try:</echo>
+        <property location="${dist.jar}" name="dist.jar.resolved"/>
+        <echo>java -jar "${dist.jar.resolved}"</echo>
+    </target>
+    <target depends="init,compile,-pre-pre-jar,-pre-jar" if="manifest.available+mkdist.available" name="-do-jar-with-libraries-without-mainclass" unless="main.class.available">
+        <property location="${build.classes.dir}" name="build.classes.dir.resolved"/>
+        <pathconvert property="run.classpath.without.build.classes.dir">
+            <path path="${run.classpath}"/>
+            <map from="${build.classes.dir.resolved}" to=""/>
+        </pathconvert>
+        <pathconvert pathsep=" " property="jar.classpath">
+            <path path="${run.classpath.without.build.classes.dir}"/>
+            <chainedmapper>
+                <flattenmapper/>
+                <globmapper from="*" to="lib/*"/>
+            </chainedmapper>
+        </pathconvert>
+        <taskdef classname="org.netbeans.modules.java.j2seproject.copylibstask.CopyLibs" classpath="${libs.CopyLibs.classpath}" name="copylibs"/>
+        <copylibs compress="${jar.compress}" jarfile="${dist.jar}" manifest="${manifest.file}" runtimeclasspath="${run.classpath.without.build.classes.dir}">
+            <fileset dir="${build.classes.dir}"/>
+            <manifest>
+                <attribute name="Class-Path" value="${jar.classpath}"/>
+            </manifest>
+        </copylibs>
+    </target>
+    <target depends="init,compile,-pre-pre-jar,-pre-jar" if="do.mkdist" name="-do-jar-with-libraries-without-manifest" unless="manifest.available">
+        <property location="${build.classes.dir}" name="build.classes.dir.resolved"/>
+        <pathconvert property="run.classpath.without.build.classes.dir">
+            <path path="${run.classpath}"/>
+            <map from="${build.classes.dir.resolved}" to=""/>
+        </pathconvert>
+        <pathconvert pathsep=" " property="jar.classpath">
+            <path path="${run.classpath.without.build.classes.dir}"/>
+            <chainedmapper>
+                <flattenmapper/>
+                <globmapper from="*" to="lib/*"/>
+            </chainedmapper>
+        </pathconvert>
+        <taskdef classname="org.netbeans.modules.java.j2seproject.copylibstask.CopyLibs" classpath="${libs.CopyLibs.classpath}" name="copylibs"/>
+        <copylibs compress="${jar.compress}" jarfile="${dist.jar}" runtimeclasspath="${run.classpath.without.build.classes.dir}">
+            <fileset dir="${build.classes.dir}"/>
+            <manifest>
+                <attribute name="Class-Path" value="${jar.classpath}"/>
+            </manifest>
+        </copylibs>
+    </target>
+    <target name="-post-jar">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,compile,-pre-jar,-do-jar-with-manifest,-do-jar-without-manifest,-do-jar-with-mainclass,-do-jar-with-libraries,-do-jar-with-libraries-without-mainclass,-do-jar-with-libraries-without-manifest,-post-jar" description="Build JAR." name="jar"/>
+    <!--
+                =================
+                EXECUTION SECTION
+                =================
+            -->
+    <target depends="init,compile" description="Run a main class." name="run">
+        <j2seproject1:java>
+            <customize>
+                <arg line="${application.args}"/>
+            </customize>
+        </j2seproject1:java>
+    </target>
+    <target name="-do-not-recompile">
+        <property name="javac.includes.binary" value=""/>
+    </target>
+    <target depends="init,compile-single" name="run-single">
+        <fail unless="run.class">Must select one file in the IDE or set run.class</fail>
+        <j2seproject1:java classname="${run.class}"/>
+    </target>
+    <target depends="init,compile-test-single" name="run-test-with-main">
+        <fail unless="run.class">Must select one file in the IDE or set run.class</fail>
+        <j2seproject1:java classname="${run.class}" classpath="${run.test.classpath}"/>
+    </target>
+    <!--
+                =================
+                DEBUGGING SECTION
+                =================
+            -->
+    <target depends="init" if="netbeans.home" name="-debug-start-debugger">
+        <j2seproject1:nbjpdastart name="${debug.class}"/>
+    </target>
+    <target depends="init" if="netbeans.home" name="-debug-start-debugger-main-test">
+        <j2seproject1:nbjpdastart classpath="${debug.test.classpath}" name="${debug.class}"/>
+    </target>
+    <target depends="init,compile" name="-debug-start-debuggee">
+        <j2seproject3:debug>
+            <customize>
+                <arg line="${application.args}"/>
+            </customize>
+        </j2seproject3:debug>
+    </target>
+    <target depends="init,compile,-debug-start-debugger,-debug-start-debuggee" description="Debug project in IDE." if="netbeans.home" name="debug"/>
+    <target depends="init" if="netbeans.home" name="-debug-start-debugger-stepinto">
+        <j2seproject1:nbjpdastart stopclassname="${main.class}"/>
+    </target>
+    <target depends="init,compile,-debug-start-debugger-stepinto,-debug-start-debuggee" if="netbeans.home" name="debug-stepinto"/>
+    <target depends="init,compile-single" if="netbeans.home" name="-debug-start-debuggee-single">
+        <fail unless="debug.class">Must select one file in the IDE or set debug.class</fail>
+        <j2seproject3:debug classname="${debug.class}"/>
+    </target>
+    <target depends="init,compile-single,-debug-start-debugger,-debug-start-debuggee-single" if="netbeans.home" name="debug-single"/>
+    <target depends="init,compile-test-single" if="netbeans.home" name="-debug-start-debuggee-main-test">
+        <fail unless="debug.class">Must select one file in the IDE or set debug.class</fail>
+        <j2seproject3:debug classname="${debug.class}" classpath="${debug.test.classpath}"/>
+    </target>
+    <target depends="init,compile-test-single,-debug-start-debugger-main-test,-debug-start-debuggee-main-test" if="netbeans.home" name="debug-test-with-main"/>
+    <target depends="init" name="-pre-debug-fix">
+        <fail unless="fix.includes">Must set fix.includes</fail>
+        <property name="javac.includes" value="${fix.includes}.java"/>
+    </target>
+    <target depends="init,-pre-debug-fix,compile-single" if="netbeans.home" name="-do-debug-fix">
+        <j2seproject1:nbjpdareload/>
+    </target>
+    <target depends="init,-pre-debug-fix,-do-debug-fix" if="netbeans.home" name="debug-fix"/>
+    <!--
+                ===============
+                JAVADOC SECTION
+                ===============
+            -->
+    <target depends="init" name="-javadoc-build">
+        <mkdir dir="${dist.javadoc.dir}"/>
+        <javadoc additionalparam="${javadoc.additionalparam}" author="${javadoc.author}" charset="UTF-8" destdir="${dist.javadoc.dir}" docencoding="UTF-8" encoding="${javadoc.encoding.used}" failonerror="true" noindex="${javadoc.noindex}" nonavbar="${javadoc.nonavbar}" notree="${javadoc.notree}" private="${javadoc.private}" source="${javac.source}" splitindex="${javadoc.splitindex}" use="${javadoc.use}" useexternalfile="true" version="${javadoc.version}" windowtitle="${javadoc.windowtitle}">
+            <classpath>
+                <path path="${javac.classpath}"/>
+            </classpath>
+            <fileset dir="${src.dir}" excludes="${excludes}" includes="${includes}">
+                <filename name="**/*.java"/>
+            </fileset>
+            <fileset dir="${build.generated.sources.dir}" erroronmissingdir="false">
+                <include name="**/*.java"/>
+            </fileset>
+        </javadoc>
+    </target>
+    <target depends="init,-javadoc-build" if="netbeans.home" name="-javadoc-browse" unless="no.javadoc.preview">
+        <nbbrowse file="${dist.javadoc.dir}/index.html"/>
+    </target>
+    <target depends="init,-javadoc-build,-javadoc-browse" description="Build Javadoc." name="javadoc"/>
+    <!--
+                =========================
+                JUNIT COMPILATION SECTION
+                =========================
+            -->
+    <target depends="init,compile" if="have.tests" name="-pre-pre-compile-test">
+        <mkdir dir="${build.test.classes.dir}"/>
+    </target>
+    <target name="-pre-compile-test">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target if="do.depend.true" name="-compile-test-depend">
+        <j2seproject3:depend classpath="${javac.test.classpath}" destdir="${build.test.classes.dir}" srcdir="${test.src.dir}"/>
+    </target>
+    <target depends="init,compile,-pre-pre-compile-test,-pre-compile-test,-compile-test-depend" if="have.tests" name="-do-compile-test">
+        <j2seproject3:javac classpath="${javac.test.classpath}" debug="true" destdir="${build.test.classes.dir}" srcdir="${test.src.dir}"/>
+        <copy todir="${build.test.classes.dir}">
+            <fileset dir="${test.src.dir}" excludes="${build.classes.excludes},${excludes}" includes="${includes}"/>
+        </copy>
+    </target>
+    <target name="-post-compile-test">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,compile,-pre-pre-compile-test,-pre-compile-test,-do-compile-test,-post-compile-test" name="compile-test"/>
+    <target name="-pre-compile-test-single">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,compile,-pre-pre-compile-test,-pre-compile-test-single" if="have.tests" name="-do-compile-test-single">
+        <fail unless="javac.includes">Must select some files in the IDE or set javac.includes</fail>
+        <j2seproject3:force-recompile destdir="${build.test.classes.dir}"/>
+        <j2seproject3:javac classpath="${javac.test.classpath}" debug="true" destdir="${build.test.classes.dir}" excludes="" includes="${javac.includes}" sourcepath="${test.src.dir}" srcdir="${test.src.dir}"/>
+        <copy todir="${build.test.classes.dir}">
+            <fileset dir="${test.src.dir}" excludes="${build.classes.excludes},${excludes}" includes="${includes}"/>
+        </copy>
+    </target>
+    <target name="-post-compile-test-single">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,compile,-pre-pre-compile-test,-pre-compile-test-single,-do-compile-test-single,-post-compile-test-single" name="compile-test-single"/>
+    <!--
+                =======================
+                JUNIT EXECUTION SECTION
+                =======================
+            -->
+    <target depends="init" if="have.tests" name="-pre-test-run">
+        <mkdir dir="${build.test.results.dir}"/>
+    </target>
+    <target depends="init,compile-test,-pre-test-run" if="have.tests" name="-do-test-run">
+        <j2seproject3:junit testincludes="**/*Test.java"/>
+    </target>
+    <target depends="init,compile-test,-pre-test-run,-do-test-run" if="have.tests" name="-post-test-run">
+        <fail if="tests.failed" unless="ignore.failing.tests">Some tests failed; see details above.</fail>
+    </target>
+    <target depends="init" if="have.tests" name="test-report"/>
+    <target depends="init" if="netbeans.home+have.tests" name="-test-browse"/>
+    <target depends="init,compile-test,-pre-test-run,-do-test-run,test-report,-post-test-run,-test-browse" description="Run unit tests." name="test"/>
+    <target depends="init" if="have.tests" name="-pre-test-run-single">
+        <mkdir dir="${build.test.results.dir}"/>
+    </target>
+    <target depends="init,compile-test-single,-pre-test-run-single" if="have.tests" name="-do-test-run-single">
+        <fail unless="test.includes">Must select some files in the IDE or set test.includes</fail>
+        <j2seproject3:junit excludes="" includes="${test.includes}"/>
+    </target>
+    <target depends="init,compile-test-single,-pre-test-run-single,-do-test-run-single" if="have.tests" name="-post-test-run-single">
+        <fail if="tests.failed" unless="ignore.failing.tests">Some tests failed; see details above.</fail>
+    </target>
+    <target depends="init,compile-test-single,-pre-test-run-single,-do-test-run-single,-post-test-run-single" description="Run single unit test." name="test-single"/>
+    <!--
+                =======================
+                JUNIT DEBUGGING SECTION
+                =======================
+            -->
+    <target depends="init,compile-test" if="have.tests" name="-debug-start-debuggee-test">
+        <fail unless="test.class">Must select one file in the IDE or set test.class</fail>
+        <property location="${build.test.results.dir}/TEST-${test.class}.xml" name="test.report.file"/>
+        <delete file="${test.report.file}"/>
+        <mkdir dir="${build.test.results.dir}"/>
+        <j2seproject3:debug classname="org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner" classpath="${ant.home}/lib/ant.jar:${ant.home}/lib/ant-junit.jar:${debug.test.classpath}">
+            <customize>
+                <syspropertyset>
+                    <propertyref prefix="test-sys-prop."/>
+                    <mapper from="test-sys-prop.*" to="*" type="glob"/>
+                </syspropertyset>
+                <arg value="${test.class}"/>
+                <arg value="showoutput=true"/>
+                <arg value="formatter=org.apache.tools.ant.taskdefs.optional.junit.BriefJUnitResultFormatter"/>
+                <arg value="formatter=org.apache.tools.ant.taskdefs.optional.junit.XMLJUnitResultFormatter,${test.report.file}"/>
+            </customize>
+        </j2seproject3:debug>
+    </target>
+    <target depends="init,compile-test" if="netbeans.home+have.tests" name="-debug-start-debugger-test">
+        <j2seproject1:nbjpdastart classpath="${debug.test.classpath}" name="${test.class}"/>
+    </target>
+    <target depends="init,compile-test-single,-debug-start-debugger-test,-debug-start-debuggee-test" name="debug-test"/>
+    <target depends="init,-pre-debug-fix,compile-test-single" if="netbeans.home" name="-do-debug-fix-test">
+        <j2seproject1:nbjpdareload dir="${build.test.classes.dir}"/>
+    </target>
+    <target depends="init,-pre-debug-fix,-do-debug-fix-test" if="netbeans.home" name="debug-fix-test"/>
+    <!--
+                =========================
+                APPLET EXECUTION SECTION
+                =========================
+            -->
+    <target depends="init,compile-single" name="run-applet">
+        <fail unless="applet.url">Must select one file in the IDE or set applet.url</fail>
+        <j2seproject1:java classname="sun.applet.AppletViewer">
+            <customize>
+                <arg value="${applet.url}"/>
+            </customize>
+        </j2seproject1:java>
+    </target>
+    <!--
+                =========================
+                APPLET DEBUGGING  SECTION
+                =========================
+            -->
+    <target depends="init,compile-single" if="netbeans.home" name="-debug-start-debuggee-applet">
+        <fail unless="applet.url">Must select one file in the IDE or set applet.url</fail>
+        <j2seproject3:debug classname="sun.applet.AppletViewer">
+            <customize>
+                <arg value="${applet.url}"/>
+            </customize>
+        </j2seproject3:debug>
+    </target>
+    <target depends="init,compile-single,-debug-start-debugger,-debug-start-debuggee-applet" if="netbeans.home" name="debug-applet"/>
+    <!--
+                ===============
+                CLEANUP SECTION
+                ===============
+            -->
+    <target name="-deps-clean-init" unless="built-clean.properties">
+        <property location="${build.dir}/built-clean.properties" name="built-clean.properties"/>
+        <delete file="${built-clean.properties}" quiet="true"/>
+    </target>
+    <target if="already.built.clean.${basedir}" name="-warn-already-built-clean">
+        <echo level="warn" message="Cycle detected: NatTraversal was already built"/>
+    </target>
+    <target depends="init,-deps-clean-init" name="deps-clean" unless="no.deps">
+        <mkdir dir="${build.dir}"/>
+        <touch file="${built-clean.properties}" verbose="false"/>
+        <property file="${built-clean.properties}" prefix="already.built.clean."/>
+        <antcall target="-warn-already-built-clean"/>
+        <propertyfile file="${built-clean.properties}">
+            <entry key="${basedir}" value=""/>
+        </propertyfile>
+    </target>
+    <target depends="init" name="-do-clean">
+        <delete dir="${build.dir}"/>
+        <delete dir="${dist.dir}" followsymlinks="false" includeemptydirs="true"/>
+    </target>
+    <target name="-post-clean">
+        <!-- Empty placeholder for easier customization. -->
+        <!-- You can override this target in the ../build.xml file. -->
+    </target>
+    <target depends="init,deps-clean,-do-clean,-post-clean" description="Clean build products." name="clean"/>
+    <target name="-check-call-dep">
+        <property file="${call.built.properties}" prefix="already.built."/>
+        <condition property="should.call.dep">
+            <not>
+                <isset property="already.built.${call.subproject}"/>
+            </not>
+        </condition>
+    </target>
+    <target depends="-check-call-dep" if="should.call.dep" name="-maybe-call-dep">
+        <ant antfile="${call.script}" inheritall="false" target="${call.target}">
+            <propertyset>
+                <propertyref prefix="transfer."/>
+                <mapper from="transfer.*" to="*" type="glob"/>
+            </propertyset>
+        </ant>
+    </target>
+</project>

nbproject/genfiles.properties

@@ -0,0 +1,8 @@
+build.xml.data.CRC32=b47783a3
+build.xml.script.CRC32=e04acb88
+build.xml.stylesheet.CRC32=958a1d3e@1.32.1.45
+# This file is used by a NetBeans-based IDE to track changes in generated files such as build-impl.xml.
+# Do not edit this file. You may delete it but then the IDE will never regenerate such files for you.
+nbproject/build-impl.xml.data.CRC32=b47783a3
+nbproject/build-impl.xml.script.CRC32=5144d085
+nbproject/build-impl.xml.stylesheet.CRC32=576378a2@1.32.1.45

nbproject/project.properties

@@ -0,0 +1,60 @@
+build.classes.dir=${build.dir}/classes
+build.classes.excludes=**/*.java,**/*.form
+# This directory is removed when the project is cleaned:
+build.dir=build
+build.generated.dir=${build.dir}/generated
+build.generated.sources.dir=${build.dir}/generated-sources
+# Only compile against the classpath explicitly listed here:
+build.sysclasspath=ignore
+build.test.classes.dir=${build.dir}/test/classes
+build.test.results.dir=${build.dir}/test/results
+debug.classpath=\
+    ${run.classpath}
+debug.test.classpath=\
+    ${run.test.classpath}
+# This directory is removed when the project is cleaned:
+dist.dir=dist
+dist.jar=${dist.dir}/NatTraversal.jar
+dist.javadoc.dir=${dist.dir}/javadoc
+excludes=
+includes=**
+jar.compress=false
+javac.classpath=
+# Space-separated list of extra javac options
+javac.compilerargs=
+javac.deprecation=false
+javac.source=1.5
+javac.target=1.5
+javac.test.classpath=\
+    ${javac.classpath}:\
+    ${build.classes.dir}:\
+    ${libs.junit.classpath}:\
+    ${libs.junit_4.classpath}
+javadoc.additionalparam=
+javadoc.author=false
+javadoc.encoding=${source.encoding}
+javadoc.noindex=false
+javadoc.nonavbar=false
+javadoc.notree=false
+javadoc.private=false
+javadoc.splitindex=true
+javadoc.use=true
+javadoc.version=false
+javadoc.windowtitle=
+main.class=com.md87.nat.test.SimpleDemo
+manifest.file=manifest.mf
+meta.inf.dir=${src.dir}/META-INF
+platform.active=default_platform
+run.classpath=\
+    ${javac.classpath}:\
+    ${build.classes.dir}
+# Space-separated list of JVM arguments used when running the project
+# (you may also define separate properties like run-sys-prop.name=value instead of -Dname=value
+# or test-sys-prop.name=value to set system properties for unit tests):
+run.jvmargs=
+run.test.classpath=\
+    ${javac.test.classpath}:\
+    ${build.test.classes.dir}
+source.encoding=UTF-8
+src.dir=src
+test.src.dir=test

nbproject/project.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://www.netbeans.org/ns/project/1">
+    <type>org.netbeans.modules.java.j2seproject</type>
+    <configuration>
+        <data xmlns="http://www.netbeans.org/ns/j2se-project/3">
+            <name>NatTraversal</name>
+            <minimum-ant-version>1.6.5</minimum-ant-version>
+            <source-roots>
+                <root id="src.dir"/>
+            </source-roots>
+            <test-roots>
+                <root id="test.src.dir"/>
+            </test-roots>
+        </data>
+    </configuration>
+</project>

src/com/md87/nat/CommsAgent.java

@@ -0,0 +1,26 @@
+/*
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+package com.md87.nat;
+
+import java.net.InetAddress;
+
+/**
+ *
+ * @author chris
+ */
+public interface CommsAgent {
+
+    void sendNATType(final NatType type);
+
+    NatType readNATType();
+
+    void sendAddress(final InetAddress address);
+    void sendPort(final int port);
+
+    InetAddress readAddress();
+    int readPort();
+
+}

src/com/md87/nat/NatTraverser.java

@@ -0,0 +1,217 @@
+/*
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+package com.md87.nat;
+
+import de.javawi.jstun.attribute.MappedAddress;
+import de.javawi.jstun.attribute.MessageAttribute;
+import de.javawi.jstun.attribute.MessageAttributeException;
+import de.javawi.jstun.attribute.MessageAttributeParsingException;
+import de.javawi.jstun.header.MessageHeader;
+import de.javawi.jstun.header.MessageHeaderParsingException;
+import de.javawi.jstun.test.DiscoveryInfo;
+import de.javawi.jstun.test.DiscoveryTest;
+import de.javawi.jstun.util.UtilityException;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.Semaphore;
+
+/**
+ *
+ * @author chris
+ */
+public class NatTraverser {
+
+    protected final CommsAgent agent;
+
+    protected InetAddress address;
+    protected DiscoveryInfo result;
+
+    protected NatType theirType;
+    protected NatType ourType;
+
+    public NatTraverser(final CommsAgent agent) {
+        this.agent = agent;
+    }
+
+    public void setInetAddress(final InetAddress address) {
+        this.address = address;
+        this.result = getDiscoveryInfo(address);
+        addressUpdated();
+    }
+
+    public void findBestInetAddress() {
+        final Semaphore threadSem = new Semaphore(0);
+
+        NatType bestType = null;
+        Map.Entry<InetAddress, DiscoveryInfo> best = null;
+
+        for (final Map.Entry<InetAddress, DiscoveryInfo> info : getDiscoveryInfos().entrySet()) {
+            if (info.getValue() == null) {
+                return;
+            }
+
+            final NatType thisType = getTypeFromDI(info.getValue());
+            if (thisType != null &&
+                    (bestType == null || thisType.ordinal() < bestType.ordinal())) {
+                bestType = thisType;
+                best = info;
+            }
+        }
+
+        if (best != null) {
+            this.address = best.getKey();
+            this.result = best.getValue();
+            addressUpdated();
+        }
+    }
+
+    protected void addressUpdated() {
+        try {
+            ourType = getTypeFromDI(result);
+
+            System.out.println("Using local IP: " + result.getLocalIP().getHostAddress()
+                    + " (remote: " + result.getPublicIP().getHostAddress() + "; iface: "
+                    + NetworkInterface.getByInetAddress(result.getLocalIP()).getName()
+                    + "; type: " + ourType + ")");
+
+            agent.sendNATType(ourType);
+
+            theirType = agent.readNATType();
+        } catch (SocketException ex) {
+            // Meh
+        }
+    }
+
+    public DatagramSocket traverse() throws UnsupportedOperationException,
+            SocketException, UtilityException, IOException,
+            MessageHeaderParsingException, MessageAttributeParsingException, InterruptedException {
+        if (!getTypeFromDI(result).canTraverseWith(theirType)) {
+            throw new UnsupportedOperationException("Cannot traverse "
+                    + "between a " + ourType + " network and a "
+                    + theirType + " network.");
+        }
+
+        final DatagramSocket sock
+                = new DatagramSocket(new InetSocketAddress(address, 0));
+        sock.connect(InetAddress.getByName("stun.dmdirc.com"), 3478);
+
+        MessageHeader sendMH = new MessageHeader(MessageHeader.MessageHeaderType.BindingRequest);
+        sendMH.generateTransactionID();
+
+        byte[] data = sendMH.getBytes();
+        DatagramPacket send = new DatagramPacket(data, data.length);
+        sock.send(send);
+
+        MessageHeader receiveMH = new MessageHeader();
+        while (!(receiveMH.equalTransactionID(sendMH))) {
+            DatagramPacket receive = new DatagramPacket(new byte[200], 200);
+            sock.receive(receive);
+            receiveMH = MessageHeader.parseHeader(receive.getData());
+            receiveMH.parseAttributes(receive.getData());
+        }
+
+        final MappedAddress ma = (MappedAddress) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.MappedAddress);
+
+        System.out.println("I'm listening on " + address.getHostAddress() + ":"
+                + sock.getLocalPort() + ". STUN server says I'm sending packets from "
+                + ma.getAddress().getInetAddress().getHostAddress() + ":"
+                + ma.getPort());
+
+        agent.sendAddress(ma.getAddress().getInetAddress());
+        agent.sendPort(ma.getPort());
+
+        final InetAddress raddr = agent.readAddress();
+        final int rport = agent.readPort();
+
+        sock.disconnect();
+        sock.connect(raddr, rport);
+
+        boolean cont;
+
+        do {
+            cont = false;
+            DatagramPacket p = new DatagramPacket("NatTraverser!".getBytes(), 13);
+            
+            try {
+                sock.send(p);
+
+                p = new DatagramPacket(new byte[13], 13);
+
+                sock.receive(p);
+            } catch (IOException ex) {
+                ex.printStackTrace();
+
+                cont = true;
+                Thread.sleep(500);
+            }
+        } while (cont);
+
+        return sock;
+    }
+
+    public static NatType getTypeFromDI(final DiscoveryInfo info) {
+        if (info.isFullCone()) {
+            return NatType.FULL_CONE;
+        } else if (info.isOpenAccess()) {
+            return NatType.OPEN;
+        } else if (info.isPortRestrictedCone()) {
+            return NatType.PORT_RESTRICTED_CONE;
+        } else if (info.isRestrictedCone()) {
+            return NatType.RESTRICTED_CONE;
+        } else if (info.isSymmetric()) {
+            return NatType.SYMMETRIC;
+        } else {
+            return null;
+        }
+    }
+
+    protected Map<InetAddress, DiscoveryInfo> getDiscoveryInfos() {
+        final Map<InetAddress, DiscoveryInfo> res
+                = new HashMap<InetAddress, DiscoveryInfo>();
+
+        try {
+            final Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces();
+            while (en.hasMoreElements()) {
+                final Enumeration<InetAddress> inen = en.nextElement().getInetAddresses();
+
+                while (inen.hasMoreElements()) {
+                    final InetAddress ia = inen.nextElement();
+                    res.put(ia, getDiscoveryInfo(ia));
+                }
+            }
+        } catch (SocketException ex) {
+            // Meh
+        }
+
+        return res;
+    }
+
+    protected DiscoveryInfo getDiscoveryInfo(final InetAddress iaddress) {
+        try {
+            return new DiscoveryTest(iaddress, "stun.dmdirc.com", 3478).test();
+        } catch (IOException ex) {
+            // Meh
+        } catch (UtilityException ex) {
+            // Meh
+        } catch (MessageAttributeException ex) {
+            // Meh
+        } catch (MessageHeaderParsingException ex) {
+            // Meh
+        }
+
+        return null;
+    }
+
+}

src/com/md87/nat/NatType.java

@@ -0,0 +1,36 @@
+/*
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+package com.md87.nat;
+
+/**
+ *
+ * @author chris
+ */
+public enum NatType {
+
+    OPEN(true),
+    FULL_CONE(true),
+    RESTRICTED_CONE(false),
+    PORT_RESTRICTED_CONE(false),
+    SYMMETRIC(false);
+
+    private final boolean canTraverseWithSymmetric;
+
+    NatType(final boolean canTraverseWithSymmetric) {
+        this.canTraverseWithSymmetric = canTraverseWithSymmetric;
+    }
+
+    public boolean canTraverseWith(final NatType type) {
+        if (type == SYMMETRIC) {
+            return canTraverseWithSymmetric;
+        } else if (this == SYMMETRIC) {
+            return type.canTraverseWith(this);
+        } else  {
+            return true;
+        }
+    }
+
+}

src/com/md87/nat/test/SimpleDemo.java

@@ -0,0 +1,105 @@
+/*
+ * To change this template, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+package com.md87.nat.test;
+
+import com.md87.nat.CommsAgent;
+import com.md87.nat.NatTraverser;
+import com.md87.nat.NatType;
+import de.javawi.jstun.attribute.MessageAttributeParsingException;
+import de.javawi.jstun.header.MessageHeaderParsingException;
+import de.javawi.jstun.util.UtilityException;
+import java.io.Console;
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+
+/**
+ *
+ * @author chris
+ */
+public class SimpleDemo implements CommsAgent {
+
+    static final Console console = System.console();
+
+    public void sendNATType(NatType type) {
+        console.printf("Nat type: %s\n", type.name());
+    }
+
+    public NatType readNATType() {
+        console.printf("Enter NAT type: ");
+        return NatType.valueOf(console.readLine().trim());
+    }
+
+    public void sendAddress(InetAddress address) {
+        console.printf("Address: %s\n", address.getHostAddress());
+    }
+
+    public void sendPort(int port) {
+        console.printf("Port: %s\n", port);
+    }
+
+    public InetAddress readAddress() {
+        console.printf("Enter address: ");
+        try {
+            return InetAddress.getByName(console.readLine().trim());
+        } catch (UnknownHostException ex) {
+            return null;
+        }
+    }
+
+    public int readPort() {
+        console.printf("Enter port: ");
+        return Integer.parseInt(console.readLine().trim());
+    }
+
+    public static void main(final String ... args) throws
+            UnsupportedOperationException, IOException, SocketException,
+            UtilityException, MessageHeaderParsingException, 
+            MessageAttributeParsingException, InterruptedException {
+        final NatTraverser traverser = new NatTraverser(new SimpleDemo());
+        traverser.findBestInetAddress();
+        
+        final DatagramSocket sock = traverser.traverse();
+
+        System.out.println("Traversal complete. Say hello!");
+
+        new Thread(new Runnable() {
+
+            public void run() {
+                while (true) {
+                    DatagramPacket p = new DatagramPacket(new byte[255], 255);
+                try {
+                    
+                        sock.receive(p);
+                        System.out.printf("<< %s\n", new String(p.getData()));
+                    
+                } catch (IOException ex) {
+                    ex.printStackTrace();
+                }
+                }
+            }
+        }).start();
+
+        new Thread(new Runnable() {
+
+            public void run() {
+                while (true) {try {
+                    DatagramPacket p = new DatagramPacket(new byte[255], 255);
+                    p.setData((console.readLine() + "\n").getBytes());
+                    sock.send(p);
+                    System.out.printf(">> %s\n", new String(p.getData()));
+                    
+                } catch (IOException ex) {
+                    ex.printStackTrace();
+                }}
+            }
+        }).start();
+    }
+
+}

src/de/javawi/jstun/attribute/ChangeRequest.java

@@ -0,0 +1,81 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import de.javawi.jstun.util.*;
+
+public class ChangeRequest extends MessageAttribute {
+   /* 
+    *  0                   1                   2                   3
+    *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    * |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 A B 0|
+    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    */
+	boolean changeIP = false;
+	boolean changePort = false;
+	
+	public ChangeRequest() {
+		super(MessageAttribute.MessageAttributeType.ChangeRequest);
+	}
+	
+	public boolean isChangeIP() {
+		return changeIP;
+	}
+	
+	public boolean isChangePort() {
+		return changePort;
+	}
+	
+	public void setChangeIP() {
+		changeIP = true;
+	}
+	
+	public void setChangePort() {
+		changePort = true;
+	}
+	
+	public byte[] getBytes() throws UtilityException {
+		byte[] result = new byte[8];
+		// message attribute header
+		// type
+		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
+		// length
+		System.arraycopy(Utility.integerToTwoBytes(4), 0, result, 2, 2);
+		
+		// change request header
+		if (changeIP) result[7] = Utility.integerToOneByte(4);
+		if (changePort) result[7] = Utility.integerToOneByte(2);
+		if (changeIP && changePort) result[7] = Utility.integerToOneByte(6);
+		return result;
+	}
+	
+	public static ChangeRequest parse(byte[] data) throws MessageAttributeParsingException {
+		try {
+			if (data.length < 4) {
+				throw new MessageAttributeParsingException("Data array too short");
+			}
+			ChangeRequest cr = new ChangeRequest();
+			int status = Utility.oneByteToInteger(data[3]);
+			switch (status) {
+			case 0: break;
+			case 2: cr.setChangePort(); break;
+			case 4: cr.setChangeIP(); break;
+			case 6: cr.setChangeIP(); cr.setChangePort(); break;
+			default: throw new MessageAttributeParsingException("Status parsing error"); 
+			}
+			return cr;
+		} catch (UtilityException ue) {
+			throw new MessageAttributeParsingException("Parsing error");
+		}
+	}
+}

src/de/javawi/jstun/attribute/ChangedAddress.java

@@ -0,0 +1,30 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import java.util.logging.Logger;
+
+
+public class ChangedAddress extends MappedResponseChangedSourceAddressReflectedFrom {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.attribute.ChangedAddress");
+	
+	public ChangedAddress() {
+		super(MessageAttribute.MessageAttributeType.ChangedAddress);
+	}
+	
+	public static MessageAttribute parse(byte[] data) throws MessageAttributeParsingException {
+		ChangedAddress ca = new ChangedAddress();
+		MappedResponseChangedSourceAddressReflectedFrom.parse(ca, data);
+		logger.finer("Message Attribute: Changed Address parsed: " + ca.toString() + ".");
+		return ca;
+	}
+}

src/de/javawi/jstun/attribute/Dummy.java

@@ -0,0 +1,42 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import de.javawi.jstun.util.Utility;
+import de.javawi.jstun.util.UtilityException;
+
+public class Dummy extends MessageAttribute {
+	int lengthValue;
+	public Dummy() {
+		super(MessageAttributeType.Dummy);
+	}
+	
+	public void setLengthValue(int length) {
+		this.lengthValue = length;
+	}
+
+	public byte[] getBytes() throws UtilityException {
+		byte[] result = new byte[lengthValue + 4];
+		//	message attribute header
+		// type
+		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
+		// length
+		System.arraycopy(Utility.integerToTwoBytes(lengthValue), 0, result, 2, 2);
+		return result;
+	}
+	
+	public static Dummy parse(byte[] data) {
+		Dummy dummy = new Dummy();
+		dummy.setLengthValue(data.length);
+		return dummy;
+	}
+}

src/de/javawi/jstun/attribute/ErrorCode.java

@@ -0,0 +1,104 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import de.javawi.jstun.util.Utility;
+import de.javawi.jstun.util.UtilityException;
+
+public class ErrorCode extends MessageAttribute {
+   /* 
+    *  0                   1                   2                   3
+    *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    * |                   0                     |Class|     Number    |
+    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    * |      Reason Phrase (variable)                                ..
+    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    */
+	
+	int responseCode;
+	String reason;
+	
+	public ErrorCode() {
+		super(MessageAttribute.MessageAttributeType.ErrorCode);
+	}
+	
+	public void setResponseCode(int responseCode) throws MessageAttributeException {
+		switch (responseCode) {
+		case 400: reason = "Bad Request"; break;
+		case 401: reason = "Unauthorized"; break;
+		case 420: reason = "Unkown Attribute"; break;
+		case 430: reason = "Stale Credentials"; break;
+		case 431: reason = "Integrity Check Failure"; break;
+		case 432: reason = "Missing Username"; break;
+		case 433: reason = "Use TLS"; break;
+		case 500: reason = "Server Error"; break;
+		case 600: reason = "Global Failure"; break;
+		default: throw new MessageAttributeException("Response Code is not valid");
+		}
+		this.responseCode = responseCode;
+	}
+	
+	public int getResponseCode() {
+		return responseCode;
+	}
+	
+	public String getReason() {
+		return reason;
+	}
+
+	public byte[] getBytes() throws UtilityException {
+		int length = reason.length();
+		// length adjustment
+		if ((length % 4) != 0) {
+			length += 4 - (length % 4);
+		}
+		// message attribute header
+		length += 4;
+		byte[] result = new byte[length];
+		// message attribute header
+		// type
+		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
+		// length
+		System.arraycopy(Utility.integerToTwoBytes(length-4), 0, result, 2, 2);
+		
+		// error code header
+		int classHeader = (int) Math.floor(((double)responseCode)/100);
+		result[6] = Utility.integerToOneByte(classHeader);
+		result[7] = Utility.integerToOneByte(responseCode%100);
+		byte[] reasonArray = reason.getBytes();
+		System.arraycopy(reasonArray, 0, result, 8, reasonArray.length);		
+		return result;
+	}
+	
+	public static ErrorCode parse(byte[] data) throws MessageAttributeParsingException {
+		try {
+			if (data.length < 4) {
+				throw new MessageAttributeParsingException("Data array too short");
+			}
+			byte classHeaderByte = data[3];
+			int classHeader = Utility.oneByteToInteger(classHeaderByte);
+			if ((classHeader < 1) || (classHeader > 6)) throw new MessageAttributeParsingException("Class parsing error");
+			byte numberByte = data[4];
+			int number = Utility.oneByteToInteger(numberByte);
+			if ((number < 0) || (number > 99)) throw new MessageAttributeParsingException("Number parsing error");
+			int responseCode = (classHeader * 100) + number;
+			ErrorCode result = new ErrorCode();
+			result.setResponseCode(responseCode);
+			return result;
+		} catch (UtilityException ue) {
+			throw new MessageAttributeParsingException("Parsing error");
+		} catch (MessageAttributeException mae) {
+			throw new MessageAttributeParsingException("Parsing error");
+		}		
+	}
+}

src/de/javawi/jstun/attribute/MappedAddress.java

@@ -0,0 +1,29 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import java.util.logging.Logger;
+
+
+public class MappedAddress extends MappedResponseChangedSourceAddressReflectedFrom {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.attribute.MappedAddress");
+	public MappedAddress() {
+		super(MessageAttribute.MessageAttributeType.MappedAddress);
+	}
+	
+	public static MessageAttribute parse(byte[] data) throws MessageAttributeParsingException {
+		MappedAddress ma = new MappedAddress();
+		MappedResponseChangedSourceAddressReflectedFrom.parse(ma, data);
+		logger.finer("Message Attribute: Mapped Address parsed: " + ma.toString() + ".");
+		return ma;
+	}
+}

src/de/javawi/jstun/attribute/MappedResponseChangedSourceAddressReflectedFrom.java

@@ -0,0 +1,107 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import de.javawi.jstun.util.*;
+
+public class MappedResponseChangedSourceAddressReflectedFrom extends MessageAttribute {
+	int port;
+	Address address;
+	
+	/*  
+	 *  0                   1                   2                   3
+	 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 * |x x x x x x x x|    Family     |           Port                |
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 * |                             Address                           |
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 */
+	public MappedResponseChangedSourceAddressReflectedFrom() {
+		super();
+		try {
+			port = 0;
+			address = new Address("0.0.0.0");
+		} catch (UtilityException ue) {
+			ue.getMessage();
+			ue.printStackTrace();
+		}
+	}
+	
+	public MappedResponseChangedSourceAddressReflectedFrom(MessageAttribute.MessageAttributeType type) {
+		super(type);
+	}
+	
+	public int getPort() {
+		return port;
+	}
+	
+	public Address getAddress() {
+		return address;
+	}
+	
+	public void setPort(int port) throws MessageAttributeException {
+		if ((port > 65536) || (port < 0)) {
+			throw new MessageAttributeException("Port value " + port + " out of range.");
+		}
+		this.port = port;
+	}
+	
+	public void setAddress(Address address) {
+		this.address = address;
+	}
+	
+	public byte[] getBytes() throws UtilityException {
+		byte[] result = new byte[12];
+		// message attribute header
+		// type
+		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
+		// length
+		System.arraycopy(Utility.integerToTwoBytes(8), 0, result, 2, 2);
+		
+		// mappedaddress header
+		// family
+		result[5] = Utility.integerToOneByte(0x01); 
+		// port
+		System.arraycopy(Utility.integerToTwoBytes(port), 0, result, 6, 2);
+		// address
+		System.arraycopy(address.getBytes(), 0, result, 8, 4);
+		return result;
+	}
+	
+	protected static MappedResponseChangedSourceAddressReflectedFrom parse(MappedResponseChangedSourceAddressReflectedFrom ma, byte[] data) throws MessageAttributeParsingException {
+		try {
+			if (data.length < 8) {
+				throw new MessageAttributeParsingException("Data array too short");
+			}
+			int family = Utility.oneByteToInteger(data[1]);
+			if (family != 0x01) throw new MessageAttributeParsingException("Family " + family + " is not supported");
+			byte[] portArray = new byte[2];
+			System.arraycopy(data, 2, portArray, 0, 2);
+			ma.setPort(Utility.twoBytesToInteger(portArray));
+			int firstOctet = Utility.oneByteToInteger(data[4]);
+			int secondOctet = Utility.oneByteToInteger(data[5]);
+			int thirdOctet = Utility.oneByteToInteger(data[6]);
+			int fourthOctet = Utility.oneByteToInteger(data[7]);
+			ma.setAddress(new Address(firstOctet, secondOctet, thirdOctet, fourthOctet));
+			return ma;
+		} catch (UtilityException ue) {
+			throw new MessageAttributeParsingException("Parsing error");
+		} catch (MessageAttributeException mae) {
+			throw new MessageAttributeParsingException("Port parsing error");
+		}
+	}
+	
+	public String toString() {
+		return "Address " +address.toString() + ", Port " + port;
+	}
+}

src/de/javawi/jstun/attribute/MessageAttribute.java

@@ -0,0 +1,115 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import java.util.logging.*;
+
+import de.javawi.jstun.util.*;
+
+
+public abstract class MessageAttribute implements MessageAttributeInterface {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.util.MessageAttribute");
+	MessageAttributeType type;
+	
+	public MessageAttribute() {
+	}
+	
+	public MessageAttribute(MessageAttributeType type) {
+		setType(type);
+	}
+	
+	public void setType(MessageAttributeType type) {
+		this.type = type;
+	}
+	
+	public MessageAttribute.MessageAttributeType getType() {
+		return type;
+	}
+	
+	public static int typeToInteger(MessageAttributeType type) {
+		if (type == MessageAttributeType.MappedAddress) return MAPPEDADDRESS;
+		if (type == MessageAttributeType.ResponseAddress) return RESPONSEADDRESS;
+		if (type == MessageAttributeType.ChangeRequest) return CHANGEREQUEST;
+		if (type == MessageAttributeType.SourceAddress) return SOURCEADDRESS;
+		if (type == MessageAttributeType.ChangedAddress) return CHANGEDADDRESS;
+		if (type == MessageAttributeType.Username) return USERNAME;
+		if (type == MessageAttributeType.Password) return PASSWORD;
+		if (type == MessageAttributeType.MessageIntegrity) return MESSAGEINTEGRITY;
+		if (type == MessageAttributeType.ErrorCode) return ERRORCODE;
+		if (type == MessageAttributeType.UnknownAttribute) return UNKNOWNATTRIBUTE;
+		if (type == MessageAttributeType.ReflectedFrom) return REFLECTEDFROM;
+		if (type == MessageAttributeType.Dummy) return DUMMY;
+		return -1;
+	}
+	
+	public static MessageAttributeType intToType(long type) {
+		if (type == MAPPEDADDRESS) return MessageAttributeType.MappedAddress;
+		if (type == RESPONSEADDRESS) return MessageAttributeType.ResponseAddress;
+		if (type == CHANGEREQUEST) return MessageAttributeType.ChangeRequest;
+		if (type == SOURCEADDRESS) return MessageAttributeType.SourceAddress;
+		if (type == CHANGEDADDRESS) return MessageAttributeType.ChangedAddress;
+		if (type == USERNAME) return MessageAttributeType.Username;
+		if (type == PASSWORD) return MessageAttributeType.Password;
+		if (type == MESSAGEINTEGRITY) return MessageAttributeType.MessageIntegrity;
+		if (type == ERRORCODE) return MessageAttributeType.ErrorCode;
+		if (type == UNKNOWNATTRIBUTE) return MessageAttributeType.UnknownAttribute;
+		if (type == REFLECTEDFROM) return MessageAttributeType.ReflectedFrom;
+		if (type == DUMMY) return MessageAttributeType.Dummy;
+		return null;
+	}
+	
+	abstract public byte[] getBytes() throws UtilityException;
+	//abstract public MessageAttribute parse(byte[] data) throws MessageAttributeParsingException;
+	
+	public int getLength() throws UtilityException {
+		int length = getBytes().length;
+		return length;
+	}
+	
+	public static MessageAttribute parseCommonHeader(byte[] data) throws MessageAttributeParsingException {
+		try {			
+			byte[] typeArray = new byte[2];
+			System.arraycopy(data, 0, typeArray, 0, 2);
+			int type = Utility.twoBytesToInteger(typeArray);
+			byte[] lengthArray = new byte[2];
+			System.arraycopy(data, 2, lengthArray, 0, 2);
+			int lengthValue = Utility.twoBytesToInteger(lengthArray);
+			byte[] valueArray = new byte[lengthValue];
+			System.arraycopy(data, 4, valueArray, 0, lengthValue);
+			MessageAttribute ma;
+			switch (type) {
+			case MAPPEDADDRESS: ma = MappedAddress.parse(valueArray); break;
+			case RESPONSEADDRESS: ma = ResponseAddress.parse(valueArray); break;
+			case CHANGEREQUEST: ma = ChangeRequest.parse(valueArray); break;
+			case SOURCEADDRESS: ma = SourceAddress.parse(valueArray); break;
+			case CHANGEDADDRESS: ma = ChangedAddress.parse(valueArray); break;
+			case USERNAME: ma = Username.parse(valueArray); break;
+			case PASSWORD: ma = Password.parse(valueArray); break;
+			case MESSAGEINTEGRITY: ma = MessageIntegrity.parse(valueArray); break;
+			case ERRORCODE: ma = ErrorCode.parse(valueArray); break;
+			case UNKNOWNATTRIBUTE: ma = UnknownAttribute.parse(valueArray); break;
+			case REFLECTEDFROM: ma = ReflectedFrom.parse(valueArray); break;
+			default:
+				if (type <= 0x7fff) {
+					throw new UnknownMessageAttributeException("Unkown mandatory message attribute", intToType(type));
+				} else {
+					logger.finer("MessageAttribute with type " + type + " unkown.");
+					ma = Dummy.parse(valueArray);
+					break;
+				}
+			}
+			return ma;
+		} catch (UtilityException ue) {
+			throw new MessageAttributeParsingException("Parsing error");
+		}
+	}
+}

src/de/javawi/jstun/attribute/MessageAttributeException.java

@@ -0,0 +1,20 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+public class MessageAttributeException extends Exception {
+	private static final long serialVersionUID = 3258131345099404850L;
+
+	public MessageAttributeException(String mesg) {
+		super(mesg);
+	}
+}

src/de/javawi/jstun/attribute/MessageAttributeInterface.java

@@ -0,0 +1,28 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+public interface MessageAttributeInterface {
+	public enum MessageAttributeType { MappedAddress, ResponseAddress, ChangeRequest, SourceAddress, ChangedAddress, Username, Password, MessageIntegrity, ErrorCode, UnknownAttribute, ReflectedFrom, Dummy };
+	final static int MAPPEDADDRESS = 0x0001;
+	final static int RESPONSEADDRESS = 0x0002;
+	final static int CHANGEREQUEST = 0x0003;
+	final static int SOURCEADDRESS = 0x0004;
+	final static int CHANGEDADDRESS = 0x0005;
+	final static int USERNAME = 0x0006;
+	final static int PASSWORD = 0x0007;
+	final static int MESSAGEINTEGRITY = 0x0008;
+	final static int ERRORCODE = 0x0009;
+	final static int UNKNOWNATTRIBUTE = 0x000a;
+	final static int REFLECTEDFROM = 0x000b;
+	final static int DUMMY = 0x0000;
+}

src/de/javawi/jstun/attribute/MessageAttributeParsingException.java

@@ -0,0 +1,20 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+public class MessageAttributeParsingException extends MessageAttributeException { 
+	private static final long serialVersionUID = 3258409534426263605L;
+
+	public MessageAttributeParsingException(String mesg) {
+		super(mesg);
+	}
+}

src/de/javawi/jstun/attribute/MessageIntegrity.java

@@ -0,0 +1,27 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+public class MessageIntegrity extends MessageAttribute {
+	// incomplete message integrity implementation
+	public MessageIntegrity() {
+		super(MessageAttribute.MessageAttributeType.MessageIntegrity);
+	}
+	
+	public byte[] getBytes() {
+		return new byte[0];
+	}
+	
+	public static MessageIntegrity parse(byte[] data) {
+		return new MessageIntegrity();
+	}
+}

src/de/javawi/jstun/attribute/Password.java

@@ -0,0 +1,64 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import de.javawi.jstun.util.Utility;
+import de.javawi.jstun.util.UtilityException;
+
+public class Password extends MessageAttribute {
+	String password;
+	
+	public Password() {
+		super(MessageAttribute.MessageAttributeType.Password);
+	}
+	
+	public Password(String password) {
+		super(MessageAttribute.MessageAttributeType.Password);
+		setPassword(password);
+	}
+	
+	public String getPassword() {
+		return password;
+	}
+	
+	public void setPassword(String password) {
+		this.password = password;
+	}
+	
+	public byte[] getBytes() throws UtilityException {
+		int length = password.length();
+		// password header
+		if ((length % 4) != 0) {
+			length += 4 - (length % 4);
+		}
+		// message attribute header
+		length += 4;
+		byte[] result = new byte[length];
+		// message attribute header
+		// type
+		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
+		// length
+		System.arraycopy(Utility.integerToTwoBytes(length - 4), 0, result, 2, 2);
+		
+		// password header
+		byte[] temp = password.getBytes();
+		System.arraycopy(temp, 0, result, 4, temp.length);
+		return result;
+	}
+	
+	public static Password parse(byte[] data) {
+		Password result = new Password();
+		String password = new String(data);
+		result.setPassword(password);
+		return result;
+	}
+}

src/de/javawi/jstun/attribute/ReflectedFrom.java

@@ -0,0 +1,31 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import java.util.logging.Logger;
+
+public class ReflectedFrom extends MappedResponseChangedSourceAddressReflectedFrom {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.attribute.ReflectedFrom");
+	
+	public ReflectedFrom() {
+		super(MessageAttribute.MessageAttributeType.ReflectedFrom);
+	}
+	
+	public static ReflectedFrom parse(byte[] data) throws MessageAttributeParsingException {
+		ReflectedFrom result = new ReflectedFrom();
+		MappedResponseChangedSourceAddressReflectedFrom.parse(result, data);
+		logger.finer("Message Attribute: ReflectedFrom parsed: " + result.toString() + ".");
+		return result;
+	}
+
+	
+}

src/de/javawi/jstun/attribute/ResponseAddress.java

@@ -0,0 +1,29 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import java.util.logging.Logger;
+
+
+public class ResponseAddress extends MappedResponseChangedSourceAddressReflectedFrom {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.attribute.ResponseAddress");
+	public ResponseAddress() {
+		super(MessageAttribute.MessageAttributeType.ResponseAddress);
+	}
+	
+	public static MessageAttribute parse(byte[] data) throws MessageAttributeParsingException {
+		ResponseAddress ra = new ResponseAddress();
+		MappedResponseChangedSourceAddressReflectedFrom.parse(ra, data);
+		logger.finer("Message Attribute: Response Address parsed: " + ra.toString() + ".");
+		return ra;
+	}
+}

src/de/javawi/jstun/attribute/SourceAddress.java

@@ -0,0 +1,29 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import java.util.logging.Logger;
+
+
+public class SourceAddress extends MappedResponseChangedSourceAddressReflectedFrom {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.attribute.SourceAddress");
+	public SourceAddress() {
+		super(MessageAttribute.MessageAttributeType.SourceAddress);
+	}
+	
+	public static MessageAttribute parse(byte[] data) throws MessageAttributeParsingException {
+		SourceAddress sa = new SourceAddress();
+		MappedResponseChangedSourceAddressReflectedFrom.parse(sa, data);
+		logger.finer("Message Attribute: Source Address parsed: " + sa.toString() + ".");
+		return sa;
+	}
+}

src/de/javawi/jstun/attribute/UnknownAttribute.java

@@ -0,0 +1,82 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import java.util.*;
+
+import de.javawi.jstun.util.Utility;
+import de.javawi.jstun.util.UtilityException;
+
+public class UnknownAttribute extends MessageAttribute {
+	/* 
+	 *  0                   1                   2                   3
+	 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 * |      Attribute 1 Type           |     Attribute 2 Type        |
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 * |      Attribute 3 Type           |     Attribute 4 Type    ...
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 */
+	
+	Vector<MessageAttributeType> unkown = new Vector<MessageAttributeType>();
+	
+	public UnknownAttribute() {
+		super(MessageAttribute.MessageAttributeType.UnknownAttribute);
+	}
+	
+	public void addAttribute(MessageAttributeType attribute) {
+		unkown.add(attribute);
+	}
+	
+	public byte[] getBytes() throws UtilityException {
+		int length = 0;
+		if (unkown.size()%2 == 1) {
+			length = 2 * (unkown.size() + 1) + 4;
+		} else {
+			length = 2 * unkown.size() + 4;
+		}
+		byte[] result = new byte[length];
+		// message attribute header
+		// type
+		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
+		// length
+		System.arraycopy(Utility.integerToTwoBytes(length - 4), 0, result, 2, 2);
+		
+		// unkown attribute header
+		Iterator<MessageAttributeType> it = unkown.iterator();
+		while(it.hasNext()) {
+			MessageAttributeType attri = it.next();
+			System.arraycopy(Utility.integerToTwoBytes(typeToInteger(attri)), 0, result, 4, 2);
+		}
+		// padding
+		if (unkown.size()%2 == 1) {
+			System.arraycopy(Utility.integerToTwoBytes(typeToInteger(unkown.elementAt(1))), 0, result, 4, 2);
+		}
+		return result;
+	}
+
+	public static UnknownAttribute parse(byte[] data) throws MessageAttributeParsingException {
+		try {
+			UnknownAttribute result = new UnknownAttribute();
+			if (data.length % 4 != 0) throw new MessageAttributeParsingException("Data array too short");
+			for (int i = 0; i < data.length; i += 4) {
+				byte[] temp = new byte[4];
+				System.arraycopy(data, i, temp, 0, 4);
+				long attri = Utility.fourBytesToLong(temp);
+				result.addAttribute(MessageAttribute.intToType(attri));
+			}
+			return result;
+		} catch (UtilityException ue) {
+			throw new MessageAttributeParsingException("Parsing error");
+		}
+	}
+}

src/de/javawi/jstun/attribute/UnknownMessageAttributeException.java

@@ -0,0 +1,18 @@
+package de.javawi.jstun.attribute;
+
+import de.javawi.jstun.attribute.MessageAttributeInterface.MessageAttributeType;
+
+public class UnknownMessageAttributeException extends MessageAttributeParsingException {
+	private static final long serialVersionUID = 5375193544145543299L;
+	
+	private MessageAttributeType type;
+	
+	public UnknownMessageAttributeException(String mesg, MessageAttributeType type) {
+		super(mesg);
+		this.type = type;
+	}
+	
+	public MessageAttributeType getType() {
+		return type;
+	}
+}

src/de/javawi/jstun/attribute/Username.java

@@ -0,0 +1,64 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.attribute;
+
+import de.javawi.jstun.util.Utility;
+import de.javawi.jstun.util.UtilityException;
+
+public class Username extends MessageAttribute {
+	String username;
+	
+	public Username() {
+		super(MessageAttribute.MessageAttributeType.Username);
+	}
+	
+	public Username(String username) {
+		super(MessageAttribute.MessageAttributeType.Username);
+		setUsername(username);
+	}
+	
+	public String getUsername() {
+		return username;
+	}
+	
+	public void setUsername(String username) {
+		this.username = username;
+	}
+	
+	public byte[] getBytes() throws UtilityException {
+		int length = username.length();
+		// username header
+		if ((length % 4) != 0) {
+			length += 4 - (length % 4);
+		}
+		// message attribute header
+		length += 4;
+		byte[] result = new byte[length];
+		// message attribute header
+		// type
+		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
+		// length
+		System.arraycopy(Utility.integerToTwoBytes(length-4), 0, result, 2, 2);
+		
+		// username header
+		byte[] temp = username.getBytes();
+		System.arraycopy(temp, 0, result, 4, temp.length);
+		return result;
+	}
+	
+	public static Username parse(byte[] data) {
+		Username result = new Username();
+		String username = new String(data);
+		result.setUsername(username);
+		return result;
+	}
+}

src/de/javawi/jstun/header/MessageHeader.java

@@ -0,0 +1,180 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.header;
+
+import de.javawi.jstun.attribute.*;
+import de.javawi.jstun.util.*;
+
+import java.util.*;
+import java.util.logging.*;
+
+public class MessageHeader implements MessageHeaderInterface {
+	/*
+	 *  0                   1                   2                   3
+     *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     * |      STUN Message Type        |         Message Length        |
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     * |
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     *
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     *                          Transaction ID
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     *                                                                 |
+     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 */
+	private static Logger logger = Logger.getLogger("de.javawi.stun.header.MessageHeader");
+	MessageHeaderType type;
+	byte[] id = new byte[16];
+	
+	TreeMap<MessageAttribute.MessageAttributeType, MessageAttribute> ma = new TreeMap<MessageAttribute.MessageAttributeType, MessageAttribute>();
+	
+	public MessageHeader() {
+		super();
+	}
+	
+	public MessageHeader(MessageHeaderType type) {
+		super();
+		setType(type);
+	}
+		
+    public void setType(MessageHeaderType type) {
+		this.type = type;
+    }
+    
+    public MessageHeaderType getType() {
+    	return type;
+    }
+	
+	public static int typeToInteger(MessageHeaderType type) {
+		if (type == MessageHeaderType.BindingRequest) return BINDINGREQUEST;
+		if (type == MessageHeaderType.BindingResponse) return BINDINGRESPONSE;
+		if (type == MessageHeaderType.BindingErrorResponse) return BINDINGERRORRESPONSE;
+		if (type == MessageHeaderType.SharedSecretRequest) return SHAREDSECRETREQUEST;
+		if (type == MessageHeaderType.SharedSecretResponse) return SHAREDSECRETRESPONSE;
+		if (type == MessageHeaderType.SharedSecretErrorResponse) return SHAREDSECRETERRORRESPONSE;
+		return -1;
+	}
+	
+	public void setTransactionID(byte[] id) {
+		System.arraycopy(id, 0, this.id, 0, 16);
+	}
+	
+	public void generateTransactionID() throws UtilityException {
+		System.arraycopy(Utility.integerToTwoBytes((int)(Math.random() * 65536)), 0, id, 0, 2);
+		System.arraycopy(Utility.integerToTwoBytes((int)(Math.random() * 65536)), 0, id, 2, 2);
+		System.arraycopy(Utility.integerToTwoBytes((int)(Math.random() * 65536)), 0, id, 4, 2);
+		System.arraycopy(Utility.integerToTwoBytes((int)(Math.random() * 65536)), 0, id, 6, 2);
+		System.arraycopy(Utility.integerToTwoBytes((int)(Math.random() * 65536)), 0, id, 8, 2);
+		System.arraycopy(Utility.integerToTwoBytes((int)(Math.random() * 65536)), 0, id, 10, 2);
+		System.arraycopy(Utility.integerToTwoBytes((int)(Math.random() * 65536)), 0, id, 12, 2);
+		System.arraycopy(Utility.integerToTwoBytes((int)(Math.random() * 65536)), 0, id, 14, 2);
+	}
+	
+	public byte[] getTransactionID() {
+		byte[] idCopy = new byte[id.length];
+		System.arraycopy(id, 0, idCopy, 0, id.length);
+		return idCopy;
+	}
+	
+	public boolean equalTransactionID(MessageHeader header) {
+		byte[] idHeader = header.getTransactionID();
+		if (idHeader.length != 16) return false;
+		if ((idHeader[0] == id[0]) && (idHeader[1] == id[1]) && (idHeader[2] == id[2]) && (idHeader[3] == id[3]) && 
+			(idHeader[4] == id[4]) && (idHeader[5] == id[5]) && (idHeader[6] == id[6]) && (idHeader[7] == id[7]) && 
+			(idHeader[8] == id[8]) && (idHeader[9] == id[9]) && (idHeader[10] == id[10]) && (idHeader[11] == id[11]) &&
+			(idHeader[12] == id[12]) && (idHeader[13] == id[13]) && (idHeader[14] == id[14]) && (idHeader[15] == id[15])) {
+			return true;
+		} else {
+			return false;
+		}
+	}
+	
+	public void addMessageAttribute(MessageAttribute attri) {
+		ma.put(attri.getType(), attri);
+	}
+	
+	public MessageAttribute getMessageAttribute(MessageAttribute.MessageAttributeType type) {
+		return ma.get(type);
+	}
+	
+	public byte[] getBytes() throws UtilityException {
+		int length = 20;
+		Iterator<MessageAttribute.MessageAttributeType> it = ma.keySet().iterator();
+		while (it.hasNext()) {
+			MessageAttribute attri = ma.get(it.next());
+			length += attri.getLength();
+		}
+		// add attribute size + attributes.getSize();
+		byte[] result = new byte[length];
+		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
+		System.arraycopy(Utility.integerToTwoBytes(length-20), 0, result, 2, 2);
+		System.arraycopy(id, 0, result, 4, 16);
+		
+		// arraycopy of attributes
+		int offset = 20;
+		it = ma.keySet().iterator();
+		while (it.hasNext()) {
+			MessageAttribute attri = ma.get(it.next());
+			System.arraycopy(attri.getBytes(), 0, result, offset, attri.getLength());
+			offset += attri.getLength();
+		}
+		return result;
+	}
+	
+	public int getLength() throws UtilityException {
+		return getBytes().length;
+	}
+	
+	public void parseAttributes(byte[] data) throws MessageAttributeParsingException {
+		try {
+			byte[] lengthArray = new byte[2];
+			System.arraycopy(data, 2, lengthArray, 0, 2);
+			int length = Utility.twoBytesToInteger(lengthArray);
+			System.arraycopy(data, 4, id, 0, 16);
+			byte[] cuttedData;
+			int offset = 20;
+			while (length > 0) {
+				cuttedData = new byte[length];
+				System.arraycopy(data, offset, cuttedData, 0, length);
+				MessageAttribute ma = MessageAttribute.parseCommonHeader(cuttedData); 
+				addMessageAttribute(ma);
+				length -= ma.getLength();
+				offset += ma.getLength();
+			}
+		} catch (UtilityException ue) {
+			throw new MessageAttributeParsingException("Parsing error");
+		}
+	}
+	
+	public static MessageHeader parseHeader(byte[] data) throws MessageHeaderParsingException {
+		try {
+			MessageHeader mh = new MessageHeader();
+			byte[] typeArray = new byte[2];
+			System.arraycopy(data, 0, typeArray, 0, 2);
+			int type = Utility.twoBytesToInteger(typeArray);
+			switch (type) {
+			case BINDINGREQUEST: mh.setType(MessageHeaderType.BindingRequest); logger.finer("Binding Request received."); break;
+			case BINDINGRESPONSE: mh.setType(MessageHeaderType.BindingResponse); logger.finer("Binding Response received."); break;
+			case BINDINGERRORRESPONSE: mh.setType(MessageHeaderType.BindingErrorResponse); logger.finer("Binding Error Response received."); break;
+			case SHAREDSECRETREQUEST: mh.setType(MessageHeaderType.SharedSecretRequest); logger.finer("Shared Secret Request received."); break;
+			case SHAREDSECRETRESPONSE: mh.setType(MessageHeaderType.SharedSecretResponse); logger.finer("Shared Secret Response received."); break;
+			case SHAREDSECRETERRORRESPONSE: mh.setType(MessageHeaderType.SharedSecretErrorResponse); logger.finer("Shared Secret Error Response received.");break;
+			default: throw new MessageHeaderParsingException("Message type " + type + "is not supported"); 
+			}
+			return mh;
+		} catch (UtilityException ue) {
+			throw new MessageHeaderParsingException("Parsing error");
+		}
+	}
+}

src/de/javawi/jstun/header/MessageHeaderException.java

@@ -0,0 +1,20 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.header;
+
+public class MessageHeaderException extends Exception {
+	private static final long serialVersionUID = 3689066248944103737L;
+
+	public MessageHeaderException(String mesg) {
+		super(mesg);
+	}
+}

src/de/javawi/jstun/header/MessageHeaderInterface.java

@@ -0,0 +1,22 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.header;
+
+public interface MessageHeaderInterface {
+	public enum MessageHeaderType { BindingRequest, BindingResponse, BindingErrorResponse, SharedSecretRequest, SharedSecretResponse, SharedSecretErrorResponse };
+	final static int BINDINGREQUEST = 0x0001;
+	final static int BINDINGRESPONSE = 0x0101;
+	final static int BINDINGERRORRESPONSE = 0x0111;
+	final static int SHAREDSECRETREQUEST = 0x0002;
+	final static int SHAREDSECRETRESPONSE = 0x0102;
+	final static int SHAREDSECRETERRORRESPONSE = 0x0112;
+}

src/de/javawi/jstun/header/MessageHeaderParsingException.java

@@ -0,0 +1,20 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.header;
+
+public class MessageHeaderParsingException extends MessageHeaderException {
+	private static final long serialVersionUID = 3544393617029607478L;
+
+	public MessageHeaderParsingException(String mesg) {
+		super(mesg);
+	}
+}

src/de/javawi/jstun/test/BindingLifetimeTest.java

@@ -0,0 +1,192 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test;
+
+import java.util.logging.*;
+import java.util.*;
+import java.io.*;
+import java.net.*;
+
+import de.javawi.jstun.attribute.*;
+import de.javawi.jstun.header.*;
+import de.javawi.jstun.util.UtilityException;
+
+public class BindingLifetimeTest {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.test.BindingLifetimeTest");
+	String stunServer;
+	int port;
+	int timeout = 300; //ms
+	MappedAddress ma;
+	Timer timer;
+	DatagramSocket initialSocket;
+	
+	// start value for binary search - should be carefully choosen
+	int upperBinarySearchLifetime = 345000; // ms
+	int lowerBinarySearchLifetime = 0;
+	int binarySearchLifetime = ( upperBinarySearchLifetime + lowerBinarySearchLifetime ) / 2;
+	
+	// lifetime value
+	int lifetime = -1; // -1 means undefined.
+	boolean completed = false;
+		
+	public BindingLifetimeTest(String stunServer, int port) {
+		super();
+		this.stunServer = stunServer;
+		this.port = port;
+		timer = new Timer(true);
+	}
+	
+	public void test() throws UtilityException, SocketException, UnknownHostException, IOException, MessageAttributeParsingException, MessageAttributeException, MessageHeaderParsingException {
+		initialSocket = new DatagramSocket();
+		initialSocket.connect(InetAddress.getByName(stunServer), port);
+		initialSocket.setSoTimeout(timeout);
+		
+		if (bindingCommunicationInitialSocket()) {
+			return;
+		}
+		BindingLifetimeTask task = new BindingLifetimeTask();
+		timer.schedule(task, binarySearchLifetime);
+		logger.finer("Timer scheduled initially: " + binarySearchLifetime + ".");
+	}
+	
+	private boolean bindingCommunicationInitialSocket() throws UtilityException, IOException, MessageHeaderParsingException, MessageAttributeParsingException {
+		MessageHeader sendMH = new MessageHeader(MessageHeader.MessageHeaderType.BindingRequest);
+		sendMH.generateTransactionID();
+		ChangeRequest changeRequest = new ChangeRequest();
+		sendMH.addMessageAttribute(changeRequest);
+		byte[] data = sendMH.getBytes();
+		
+		DatagramPacket send = new DatagramPacket(data, data.length, InetAddress.getByName(stunServer), port);
+		initialSocket.send(send);
+		logger.finer("Binding Request sent.");
+	
+		MessageHeader receiveMH = new MessageHeader();
+		while (!(receiveMH.equalTransactionID(sendMH))) {
+			DatagramPacket receive = new DatagramPacket(new byte[200], 200);
+			initialSocket.receive(receive);
+			receiveMH = MessageHeader.parseHeader(receive.getData());
+			receiveMH.parseAttributes(receive.getData());
+		}
+		ma = (MappedAddress) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.MappedAddress);
+		ErrorCode ec = (ErrorCode) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.ErrorCode);
+		if (ec != null) {
+			logger.config("Message header contains an Errorcode message attribute.");
+			return true;
+		}
+		if (ma == null) {
+			logger.config("Response does not contain a Mapped Address message attribute.");
+			return true;
+		}
+		return false;
+	}
+	
+	public int getLifetime() {
+		return lifetime;
+	}
+	
+	public boolean isCompleted() {
+		return completed;
+	}
+	
+	public void setUpperBinarySearchLifetime(int upperBinarySearchLifetime) {
+		this.upperBinarySearchLifetime = upperBinarySearchLifetime;
+		binarySearchLifetime = ( upperBinarySearchLifetime + lowerBinarySearchLifetime ) / 2;
+	}
+	
+	class BindingLifetimeTask extends TimerTask {
+		
+		public BindingLifetimeTask() {
+			super();
+		}
+		
+		public void run() {
+			try {
+				lifetimeQuery();
+			} catch (Exception e) {
+				logger.config("Unhandled Exception. BindLifetimeTasks stopped.");
+				e.printStackTrace();
+			}
+		}
+		
+		public void lifetimeQuery() throws UtilityException, MessageAttributeException, MessageHeaderParsingException, MessageAttributeParsingException, IOException {
+			try {
+				DatagramSocket socket = new DatagramSocket();
+				socket.connect(InetAddress.getByName(stunServer), port);
+				socket.setSoTimeout(timeout);
+			
+				MessageHeader sendMH = new MessageHeader(MessageHeader.MessageHeaderType.BindingRequest);
+				sendMH.generateTransactionID();
+				ChangeRequest changeRequest = new ChangeRequest();
+				ResponseAddress responseAddress = new ResponseAddress();
+				responseAddress.setAddress(ma.getAddress());
+				responseAddress.setPort(ma.getPort());
+				sendMH.addMessageAttribute(changeRequest);
+				sendMH.addMessageAttribute(responseAddress);
+				byte[] data = sendMH.getBytes();
+			
+				DatagramPacket send = new DatagramPacket(data, data.length, InetAddress.getByName(stunServer), port);
+				socket.send(send);
+				logger.finer("Binding Request sent.");
+		
+				MessageHeader receiveMH = new MessageHeader();
+				while (!(receiveMH.equalTransactionID(sendMH))) {
+					DatagramPacket receive = new DatagramPacket(new byte[200], 200);
+					initialSocket.receive(receive);
+					receiveMH = MessageHeader.parseHeader(receive.getData());
+					receiveMH.parseAttributes(receive.getData());
+				}
+				ErrorCode ec = (ErrorCode) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.ErrorCode);
+				if (ec != null) {
+					logger.config("Message header contains errorcode message attribute.");
+					return;
+				}
+				logger.finer("Binding Response received.");
+				if (upperBinarySearchLifetime == (lowerBinarySearchLifetime + 1)) {
+					logger.config("BindingLifetimeTest completed. UDP binding lifetime: " + binarySearchLifetime + ".");
+					completed = true;
+					return;
+				}
+				lifetime = binarySearchLifetime;
+				logger.finer("Lifetime update: " + lifetime + ".");
+				lowerBinarySearchLifetime = binarySearchLifetime;
+				binarySearchLifetime = ( upperBinarySearchLifetime + lowerBinarySearchLifetime ) / 2;
+				if (binarySearchLifetime > 0) {
+					BindingLifetimeTask task = new BindingLifetimeTask();
+					timer.schedule(task, binarySearchLifetime);
+					logger.finer("Timer scheduled: " + binarySearchLifetime + ".");
+				} else {
+					completed = true;
+				}
+			} catch (SocketTimeoutException ste) {
+				logger.finest("Read operation at query socket timeout.");
+				if (upperBinarySearchLifetime == (lowerBinarySearchLifetime + 1)) {
+					logger.config("BindingLifetimeTest completed. UDP binding lifetime: " + binarySearchLifetime + ".");
+					completed = true;
+					return;
+				}
+				upperBinarySearchLifetime = binarySearchLifetime;
+				binarySearchLifetime = ( upperBinarySearchLifetime + lowerBinarySearchLifetime ) / 2;
+				if (binarySearchLifetime > 0) {
+					if (bindingCommunicationInitialSocket()) {
+						return;
+					}
+					BindingLifetimeTask task = new BindingLifetimeTask();
+					timer.schedule(task, binarySearchLifetime);
+					logger.finer("Timer scheduled: " + binarySearchLifetime + ".");
+				} else {
+					completed = true;
+				}
+			}
+		}
+	}
+}
+

src/de/javawi/jstun/test/DiscoveryInfo.java

@@ -0,0 +1,153 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test;
+
+import java.net.*;
+
+public class DiscoveryInfo {
+	private InetAddress testIP;
+	private boolean error = false;
+	private int errorResponseCode = 0;
+	private String errorReason;
+	private boolean openAccess = false;
+	private boolean blockedUDP = false;
+	private boolean fullCone = false;
+	private boolean restrictedCone = false;
+	private boolean portRestrictedCone = false;
+	private boolean symmetric = false;
+	private boolean symmetricUDPFirewall = false;
+	private InetAddress publicIP;
+	
+	public DiscoveryInfo(InetAddress testIP) {
+		this.testIP = testIP;
+	}
+	
+	public boolean isError() {
+		return error;
+	}
+	
+	public void setError(int responseCode, String reason) {
+		this.error = true;
+		this.errorResponseCode = responseCode;
+		this.errorReason = reason;
+	}
+	
+	public boolean isOpenAccess() {
+		if (error) return false;
+		return openAccess;
+	}
+
+	public void setOpenAccess() {
+		this.openAccess = true;
+	}
+
+	public boolean isBlockedUDP() {
+		if (error) return false;
+		return blockedUDP;
+	}
+
+	public void setBlockedUDP() {
+		this.blockedUDP = true;
+	}
+	
+	public boolean isFullCone() {
+		if (error) return false;
+		return fullCone;
+	}
+
+	public void setFullCone() {
+		this.fullCone = true;
+	}
+
+	public boolean isPortRestrictedCone() {
+		if (error) return false;
+		return portRestrictedCone;
+	}
+
+	public void setPortRestrictedCone() {
+		this.portRestrictedCone = true;
+	}
+
+	public boolean isRestrictedCone() {
+		if (error) return false;
+		return restrictedCone;
+	}
+
+	public void setRestrictedCone() {
+		this.restrictedCone = true;
+	}
+
+	public boolean isSymmetric() {
+		if (error) return false;
+		return symmetric;
+	}
+
+	public void setSymmetric() {
+		this.symmetric = true;
+	}
+
+	public boolean isSymmetricUDPFirewall() {
+		if (error) return false;
+		return symmetricUDPFirewall;
+	}
+
+	public void setSymmetricUDPFirewall() {
+		this.symmetricUDPFirewall = true;
+	}
+	
+	public InetAddress getPublicIP() {
+		return publicIP;
+	}
+	
+	public InetAddress getLocalIP() {
+		return testIP;
+	}
+	
+	public void setPublicIP(InetAddress publicIP) {
+		this.publicIP = publicIP;
+	}
+	
+	public String toString() {
+		StringBuffer sb = new StringBuffer();
+		sb.append("Network interface: ");
+		try {
+			sb.append(NetworkInterface.getByInetAddress(testIP).getName());
+		} catch (SocketException se) {
+			sb.append("unknown");
+		}
+		sb.append("\n");
+		sb.append("Local IP address: ");
+		sb.append(testIP.getHostAddress());
+		sb.append("\n");
+		if (error) {
+			sb.append(errorReason + " - Responsecode: " + errorResponseCode);
+			return sb.toString();
+		}
+		sb.append("Result: ");
+		if (openAccess) sb.append("Open access to the Internet.\n");
+		if (blockedUDP) sb.append("Firewall blocks UDP.\n");
+		if (fullCone) sb.append("Full Cone NAT handles connections.\n");
+		if (restrictedCone) sb.append("Restricted Cone NAT handles connections.\n");
+		if (portRestrictedCone) sb.append("Port restricted Cone NAT handles connections.\n");
+		if (symmetric) sb.append("Symmetric Cone NAT handles connections.\n");
+		if (symmetricUDPFirewall) sb.append ("Symmetric UDP Firewall handles connections.\n");
+		if (!openAccess && !blockedUDP && !fullCone && !restrictedCone && !portRestrictedCone && !symmetric && !symmetricUDPFirewall) sb.append("unkown\n");
+		sb.append("Public IP address: ");
+		if (publicIP != null) {
+			sb.append(publicIP.getHostAddress());
+		} else {
+			sb.append("unknown");
+		}
+		sb.append("\n");
+		return sb.toString();
+	}	
+}

src/de/javawi/jstun/test/DiscoveryTest.java

@@ -0,0 +1,347 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.SocketException;
+import java.net.SocketTimeoutException;
+import java.net.UnknownHostException;
+import java.util.logging.Logger;
+
+import de.javawi.jstun.attribute.ChangeRequest;
+import de.javawi.jstun.attribute.ChangedAddress;
+import de.javawi.jstun.attribute.ErrorCode;
+import de.javawi.jstun.attribute.MappedAddress;
+import de.javawi.jstun.attribute.MessageAttribute;
+import de.javawi.jstun.attribute.MessageAttributeException;
+import de.javawi.jstun.attribute.MessageAttributeParsingException;
+import de.javawi.jstun.header.MessageHeader;
+import de.javawi.jstun.header.MessageHeaderParsingException;
+import de.javawi.jstun.util.UtilityException;
+
+public class DiscoveryTest {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.test.DiscoveryTest");
+	InetAddress iaddress;
+	String stunServer;
+	int port;
+	int timeoutInitValue = 300; //ms
+	MappedAddress ma = null;
+	ChangedAddress ca = null;
+	boolean nodeNatted = true;
+	DatagramSocket socketTest1 = null;
+	DiscoveryInfo di = null;
+	
+	public DiscoveryTest(InetAddress iaddress , String stunServer, int port) {
+		super();
+		this.iaddress = iaddress;
+		this.stunServer = stunServer;
+		this.port = port;
+	}
+		
+	public DiscoveryInfo test() throws UtilityException, SocketException, UnknownHostException, IOException, MessageAttributeParsingException, MessageAttributeException, MessageHeaderParsingException{
+		ma = null;
+		ca = null;
+		nodeNatted = true;
+		socketTest1 = null;
+		di = new DiscoveryInfo(iaddress);
+		
+		if (test1()) {
+			if (test2()) {
+				if (test1Redo()) {
+					test3();
+				}
+			}
+		}
+		
+		socketTest1.close();
+		
+		return di;
+	}
+	
+	private boolean test1() throws UtilityException, SocketException, UnknownHostException, IOException, MessageAttributeParsingException, MessageHeaderParsingException {
+		int timeSinceFirstTransmission = 0;
+		int timeout = timeoutInitValue;
+		while (true) {
+			try {
+				// Test 1 including response
+				socketTest1 = new DatagramSocket(new InetSocketAddress(iaddress, 0));
+				socketTest1.setReuseAddress(true);
+				socketTest1.connect(InetAddress.getByName(stunServer), port);
+				socketTest1.setSoTimeout(timeout);
+				
+				MessageHeader sendMH = new MessageHeader(MessageHeader.MessageHeaderType.BindingRequest);
+				sendMH.generateTransactionID();
+				
+				ChangeRequest changeRequest = new ChangeRequest();
+				sendMH.addMessageAttribute(changeRequest);
+				
+				byte[] data = sendMH.getBytes();
+				DatagramPacket send = new DatagramPacket(data, data.length);
+				socketTest1.send(send);
+				logger.finer("Test 1: Binding Request sent.");
+			
+				MessageHeader receiveMH = new MessageHeader();
+				while (!(receiveMH.equalTransactionID(sendMH))) {
+					DatagramPacket receive = new DatagramPacket(new byte[200], 200);
+					socketTest1.receive(receive);
+					receiveMH = MessageHeader.parseHeader(receive.getData());
+					receiveMH.parseAttributes(receive.getData());
+				}
+				
+				ma = (MappedAddress) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.MappedAddress);
+				ca = (ChangedAddress) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.ChangedAddress);
+				ErrorCode ec = (ErrorCode) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.ErrorCode);
+				if (ec != null) {
+					di.setError(ec.getResponseCode(), ec.getReason());
+					logger.config("Message header contains an Errorcode message attribute.");
+					return false;
+				}
+				if ((ma == null) || (ca == null)) {
+					di.setError(700, "The server is sending an incomplete response (Mapped Address and Changed Address message attributes are missing). The client should not retry.");
+					logger.config("Response does not contain a Mapped Address or Changed Address message attribute.");
+					return false;
+				} else {
+					di.setPublicIP(ma.getAddress().getInetAddress());
+					if ((ma.getPort() == socketTest1.getLocalPort()) && (ma.getAddress().getInetAddress().equals(socketTest1.getLocalAddress()))) {
+						logger.fine("Node is not natted.");
+						nodeNatted = false;
+					} else {
+						logger.fine("Node is natted.");
+					}
+					return true;
+				}
+			} catch (SocketTimeoutException ste) {
+				if (timeSinceFirstTransmission < 7900) {
+					logger.finer("Test 1: Socket timeout while receiving the response.");
+					timeSinceFirstTransmission += timeout;
+					int timeoutAddValue = (timeSinceFirstTransmission * 2);
+					if (timeoutAddValue > 1600) timeoutAddValue = 1600;
+					timeout = timeoutAddValue;
+				} else {
+					// node is not capable of udp communication
+					logger.finer("Test 1: Socket timeout while receiving the response. Maximum retry limit exceed. Give up.");
+					di.setBlockedUDP();
+					logger.fine("Node is not capable of UDP communication.");
+					return false;
+				}
+			} 
+		}
+	}
+		
+	private boolean test2() throws UtilityException, SocketException, UnknownHostException, IOException, MessageAttributeParsingException, MessageAttributeException, MessageHeaderParsingException {
+		int timeSinceFirstTransmission = 0;
+		int timeout = timeoutInitValue;
+		while (true) {
+			try {
+				// Test 2 including response
+				DatagramSocket sendSocket = new DatagramSocket(new InetSocketAddress(iaddress, 0));
+				sendSocket.connect(InetAddress.getByName(stunServer), port);
+				sendSocket.setSoTimeout(timeout);
+				
+				MessageHeader sendMH = new MessageHeader(MessageHeader.MessageHeaderType.BindingRequest);
+				sendMH.generateTransactionID();
+				
+				ChangeRequest changeRequest = new ChangeRequest();
+				changeRequest.setChangeIP();
+				changeRequest.setChangePort();
+				sendMH.addMessageAttribute(changeRequest);
+					 
+				byte[] data = sendMH.getBytes(); 
+				DatagramPacket send = new DatagramPacket(data, data.length);
+				sendSocket.send(send);
+				logger.finer("Test 2: Binding Request sent.");
+				
+				int localPort = sendSocket.getLocalPort();
+				InetAddress localAddress = sendSocket.getLocalAddress();
+				
+				sendSocket.close();
+				
+				DatagramSocket receiveSocket = new DatagramSocket(localPort, localAddress);
+				receiveSocket.connect(ca.getAddress().getInetAddress(), ca.getPort());
+				receiveSocket.setSoTimeout(timeout);
+				
+				MessageHeader receiveMH = new MessageHeader();
+				while(!(receiveMH.equalTransactionID(sendMH))) {
+					DatagramPacket receive = new DatagramPacket(new byte[200], 200);
+					receiveSocket.receive(receive);
+					receiveMH = MessageHeader.parseHeader(receive.getData());
+					receiveMH.parseAttributes(receive.getData());
+				}
+				ErrorCode ec = (ErrorCode) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.ErrorCode);
+				if (ec != null) {
+					di.setError(ec.getResponseCode(), ec.getReason());
+					logger.config("Message header contains an Errorcode message attribute.");
+					return false;
+				}
+				if (!nodeNatted) {
+					di.setOpenAccess();
+					logger.fine("Node has open access to the Internet (or, at least the node is behind a full-cone NAT without translation).");
+				} else {
+					di.setFullCone();
+					logger.fine("Node is behind a full-cone NAT.");
+				}
+				return false;
+			} catch (SocketTimeoutException ste) {
+				if (timeSinceFirstTransmission < 7900) {
+					logger.finer("Test 2: Socket timeout while receiving the response.");
+					timeSinceFirstTransmission += timeout;
+					int timeoutAddValue = (timeSinceFirstTransmission * 2);
+					if (timeoutAddValue > 1600) timeoutAddValue = 1600;
+					timeout = timeoutAddValue;
+				} else {
+					logger.finer("Test 2: Socket timeout while receiving the response. Maximum retry limit exceed. Give up.");
+					if (!nodeNatted) {
+						di.setSymmetricUDPFirewall();
+						logger.fine("Node is behind a symmetric UDP firewall.");
+						return false;
+					} else {
+						// not is natted
+						// redo test 1 with address and port as offered in the changed-address message attribute
+						return true;
+					}
+				}
+			}
+		}
+	}
+	
+	private boolean test1Redo() throws UtilityException, SocketException, UnknownHostException, IOException, MessageAttributeParsingException, MessageHeaderParsingException{
+		int timeSinceFirstTransmission = 0;
+		int timeout = timeoutInitValue;
+		while (true) {
+			// redo test 1 with address and port as offered in the changed-address message attribute
+			try {
+				// Test 1 with changed port and address values
+				socketTest1.connect(ca.getAddress().getInetAddress(), ca.getPort());
+				socketTest1.setSoTimeout(timeout);
+				
+				MessageHeader sendMH = new MessageHeader(MessageHeader.MessageHeaderType.BindingRequest);
+				sendMH.generateTransactionID();
+				
+				ChangeRequest changeRequest = new ChangeRequest();
+				sendMH.addMessageAttribute(changeRequest);
+				
+				byte[] data = sendMH.getBytes();
+				DatagramPacket send = new DatagramPacket(data, data.length);
+				socketTest1.send(send);
+				logger.finer("Test 1 redo with changed address: Binding Request sent.");
+				
+				MessageHeader receiveMH = new MessageHeader();
+				while (!(receiveMH.equalTransactionID(sendMH))) {
+					DatagramPacket receive = new DatagramPacket(new byte[200], 200);
+					socketTest1.receive(receive);
+					receiveMH = MessageHeader.parseHeader(receive.getData());
+					receiveMH.parseAttributes(receive.getData());
+				}
+				MappedAddress ma2 = (MappedAddress) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.MappedAddress);
+				ErrorCode ec = (ErrorCode) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.ErrorCode);
+				if (ec != null) {
+					di.setError(ec.getResponseCode(), ec.getReason());
+					logger.config("Message header contains an Errorcode message attribute.");
+					return false;
+				}
+				if (ma2 == null) {
+					di.setError(700, "The server is sending an incomplete response (Mapped Address message attribute is missing). The client should not retry.");
+					logger.config("Response does not contain a Mapped Address message attribute.");
+					return false;
+				} else {
+					if ((ma.getPort() != ma2.getPort()) || (!(ma.getAddress().getInetAddress().equals(ma2.getAddress().getInetAddress())))) {
+						di.setSymmetric();
+						logger.fine("Node is behind a symmetric NAT.");
+						return false;
+					}
+				}
+				return true;
+			} catch (SocketTimeoutException ste2) {
+				if (timeSinceFirstTransmission < 7900) {
+					logger.config("Test 1 redo with changed address: Socket timeout while receiving the response.");
+					timeSinceFirstTransmission += timeout;
+					int timeoutAddValue = (timeSinceFirstTransmission * 2);
+					if (timeoutAddValue > 1600) timeoutAddValue = 1600;
+					timeout = timeoutAddValue;
+				} else {
+					logger.config("Test 1 redo with changed address: Socket timeout while receiving the response.  Maximum retry limit exceed. Give up.");
+					return false;
+				}
+			}
+		}
+	}
+	
+	private void test3() throws UtilityException, SocketException, UnknownHostException, IOException, MessageAttributeParsingException, MessageAttributeException, MessageHeaderParsingException {
+		int timeSinceFirstTransmission = 0;
+		int timeout = timeoutInitValue;
+		while (true) {
+			try {
+				// Test 3 including response
+				DatagramSocket sendSocket = new DatagramSocket(new InetSocketAddress(iaddress, 0));
+				sendSocket.connect(InetAddress.getByName(stunServer), port);
+				sendSocket.setSoTimeout(timeout);
+				
+				MessageHeader sendMH = new MessageHeader(MessageHeader.MessageHeaderType.BindingRequest);
+				sendMH.generateTransactionID();
+				
+				ChangeRequest changeRequest = new ChangeRequest();
+				changeRequest.setChangePort();
+				sendMH.addMessageAttribute(changeRequest);
+				
+				byte[] data = sendMH.getBytes();
+				DatagramPacket send = new DatagramPacket(data, data.length);
+				sendSocket.send(send);
+				logger.finer("Test 3: Binding Request sent.");
+				
+				int localPort = sendSocket.getLocalPort();
+				InetAddress localAddress = sendSocket.getLocalAddress();
+				
+				sendSocket.close();
+				
+				DatagramSocket receiveSocket = new DatagramSocket(localPort, localAddress);
+				receiveSocket.connect(InetAddress.getByName(stunServer), ca.getPort());
+				receiveSocket.setSoTimeout(timeout);
+				
+				MessageHeader receiveMH = new MessageHeader();
+				while (!(receiveMH.equalTransactionID(sendMH))) {
+					DatagramPacket receive = new DatagramPacket(new byte[200], 200);
+					receiveSocket.receive(receive);
+					receiveMH = MessageHeader.parseHeader(receive.getData());
+					receiveMH.parseAttributes(receive.getData());
+				}
+				ErrorCode ec = (ErrorCode) receiveMH.getMessageAttribute(MessageAttribute.MessageAttributeType.ErrorCode);
+				if (ec != null) {
+					di.setError(ec.getResponseCode(), ec.getReason());
+					logger.config("Message header contains an Errorcode message attribute.");
+					return;
+				}
+				if (nodeNatted) {
+					di.setRestrictedCone();
+					logger.fine("Node is behind a restricted NAT.");
+					return;
+				}
+			} catch (SocketTimeoutException ste) {
+				if (timeSinceFirstTransmission < 7900) {
+					logger.finer("Test 3: Socket timeout while receiving the response.");
+					timeSinceFirstTransmission += timeout;
+					int timeoutAddValue = (timeSinceFirstTransmission * 2);
+					if (timeoutAddValue > 1600) timeoutAddValue = 1600;
+					timeout = timeoutAddValue;
+				} else {
+					logger.finer("Test 3: Socket timeout while receiving the response. Maximum retry limit exceed. Give up.");
+					di.setPortRestrictedCone();
+					logger.fine("Node is behind a port restricted NAT.");
+					return;
+				}
+			}
+		}
+	}
+}

src/de/javawi/jstun/test/demo/.#DiscoveryTestDemo.java.1.3

@@ -0,0 +1,73 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test.demo;
+
+import java.net.BindException;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.util.Enumeration;
+import java.util.logging.FileHandler;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.logging.SimpleFormatter;
+
+import de.javawi.jstun.test.DiscoveryTest;
+
+public class DiscoveryTestDemo implements Runnable {
+	InetAddress iaddress;
+	
+	public DiscoveryTestDemo(InetAddress iaddress) {
+		this.iaddress = iaddress;
+	}
+	
+	public void run() {
+		try {
+			DiscoveryTest test = new DiscoveryTest(iaddress, "stun.sipgate.net", 10000);
+			//DiscoveryTest test = new DiscoveryTest(iaddress, "stun.sipgate.net", 10000);
+			// iphone-stun.freenet.de:3478
+			// larry.gloo.net:3478
+			// stun.xten.net:3478
+			// stun.sipgate.net:10000
+			System.out.println(test.test());
+		} catch (BindException be) {
+			System.out.println(iaddress.toString() + ": " + be.getMessage());
+		} catch (Exception e) {
+			System.out.println(e.getMessage());
+			e.printStackTrace();
+		}
+	}
+	
+	public static void main(String[] args) {
+		try {
+			Handler fh = new FileHandler("logging.txt");
+			fh.setFormatter(new SimpleFormatter());
+			Logger.getLogger("de.javawi.stun").addHandler(fh);
+			Logger.getLogger("de.javawi.stun").setLevel(Level.ALL);
+
+			Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces();
+			while (ifaces.hasMoreElements()) {
+				NetworkInterface iface = ifaces.nextElement();
+				Enumeration<InetAddress> iaddresses = iface.getInetAddresses();
+				while (iaddresses.hasMoreElements()) {
+					InetAddress iaddress = iaddresses.nextElement();
+					if (!iaddress.isLoopbackAddress() && !iaddress.isLinkLocalAddress()) {
+						Thread thread = new Thread(new DiscoveryTestDemo(iaddress));
+						thread.start();
+					}
+				}
+			}
+		} catch (Exception e) {
+			System.out.println(e.getMessage());
+		}
+	}
+}

src/de/javawi/jstun/test/demo/.#DiscoveryTestDemo.java.1.7

@@ -0,0 +1,73 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test.demo;
+
+import java.net.BindException;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.util.Enumeration;
+import java.util.logging.FileHandler;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.logging.SimpleFormatter;
+
+import de.javawi.jstun.test.DiscoveryTest;
+
+public class DiscoveryTestDemo implements Runnable {
+	InetAddress iaddress;
+	
+	public DiscoveryTestDemo(InetAddress iaddress) {
+		this.iaddress = iaddress;
+	}
+	
+	public void run() {
+		try {
+			DiscoveryTest test = new DiscoveryTest(iaddress, "jstun.javawi.de", 3478);
+			//DiscoveryTest test = new DiscoveryTest(iaddress, "stun.sipgate.net", 10000);
+			// iphone-stun.freenet.de:3478
+			// larry.gloo.net:3478
+			// stun.xten.net:3478
+			// stun.sipgate.net:10000
+			System.out.println(test.test());
+		} catch (BindException be) {
+			System.out.println(iaddress.toString() + ": " + be.getMessage());
+		} catch (Exception e) {
+			System.out.println(e.getMessage());
+			e.printStackTrace();
+		}
+	}
+	
+	public static void main(String args[]) {
+		try {
+			Handler fh = new FileHandler("logging.txt");
+			fh.setFormatter(new SimpleFormatter());
+			Logger.getLogger("de.javawi.stun").addHandler(fh);
+			Logger.getLogger("de.javawi.stun").setLevel(Level.ALL);
+
+			Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces();
+			while (ifaces.hasMoreElements()) {
+				NetworkInterface iface = ifaces.nextElement();
+				Enumeration<InetAddress> iaddresses = iface.getInetAddresses();
+				while (iaddresses.hasMoreElements()) {
+					InetAddress iaddress = iaddresses.nextElement();
+					if (!iaddress.isLoopbackAddress() && !iaddress.isLinkLocalAddress()) {
+						Thread thread = new Thread(new DiscoveryTestDemo(iaddress));
+						thread.start();
+					}
+				}
+			}
+		} catch (Exception e) {
+			System.out.println(e.getMessage());
+		}
+	}
+}

src/de/javawi/jstun/test/demo/BindingLifetimeTestDemo.java

@@ -0,0 +1,47 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test.demo;
+
+import java.util.logging.FileHandler;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.logging.SimpleFormatter;
+
+import de.javawi.jstun.test.BindingLifetimeTest;
+
+public class BindingLifetimeTestDemo {
+	public static void main(String args[]) {
+		try {
+			Handler fh = new FileHandler("logging.txt");
+			fh.setFormatter(new SimpleFormatter());
+			Logger.getLogger("de.javawi.stun").addHandler(fh);
+			Logger.getLogger("de.javawi.stun").setLevel(Level.ALL);
+			BindingLifetimeTest test = new BindingLifetimeTest("iphone-stun.freenet.de", 3478);
+			// iphone-stun.freenet.de:3478
+			// larry.gloo.net:3478
+			// stun.xten.net:3478
+			test.test();
+			boolean continueWhile = true;
+			while(continueWhile) {
+				Thread.sleep(5000);
+				if (test.getLifetime() != -1) {
+					System.out.println("Lifetime: " + test.getLifetime() + " Finished: " + test.isCompleted());
+					if (test.isCompleted()) continueWhile = false;
+				}
+			}
+		} catch (Exception e) {
+			System.out.println(e.getMessage());
+			e.printStackTrace();
+		}
+	}
+}

src/de/javawi/jstun/test/demo/DiscoveryTestDemo.java

@@ -0,0 +1,75 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test.demo;
+
+import java.net.BindException;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.util.Enumeration;
+import java.util.logging.FileHandler;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.logging.SimpleFormatter;
+
+import de.javawi.jstun.test.DiscoveryTest;
+
+public class DiscoveryTestDemo implements Runnable {
+	InetAddress iaddress;
+	
+	public DiscoveryTestDemo(InetAddress iaddress) {
+		this.iaddress = iaddress;
+	}
+	
+	public void run() {
+		try {
+			DiscoveryTest test = new DiscoveryTest(iaddress, "jstun.javawi.de", 3478);
+			//DiscoveryTest test = new DiscoveryTest(iaddress, "stun.sipgate.net", 10000);
+			// iphone-stun.freenet.de:3478
+			// larry.gloo.net:3478
+			// stun.xten.net:3478
+			// stun.sipgate.net:10000
+			System.out.println(test.test());
+		} catch (BindException be) {
+			System.out.println(iaddress.toString() + ": " + be.getMessage());
+		} catch (Exception e) {
+			System.out.println(e.getMessage());
+			e.printStackTrace();
+		}
+	}
+	
+	public static void main(String args[]) {
+		try {
+			Handler fh = new FileHandler("logging.txt");
+			fh.setFormatter(new SimpleFormatter());
+			Logger.getLogger("de.javawi.stun").addHandler(fh);
+			Logger.getLogger("de.javawi.stun").setLevel(Level.ALL);
+
+			Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces();
+			while (ifaces.hasMoreElements()) {
+				NetworkInterface iface = ifaces.nextElement();
+				Enumeration<InetAddress> iaddresses = iface.getInetAddresses();
+				while (iaddresses.hasMoreElements()) {
+					InetAddress iaddress = iaddresses.nextElement();
+					if (Class.forName("java.net.Inet4Address").isInstance(iaddress)) {
+						if ((!iaddress.isLoopbackAddress()) && (!iaddress.isLinkLocalAddress())) {
+							Thread thread = new Thread(new DiscoveryTestDemo(iaddress));
+							thread.start();
+						}
+					}
+				}
+			}
+		} catch (Exception e) {
+			System.out.println(e.getMessage());
+		}
+	}
+}

src/de/javawi/jstun/test/demo/StunServer.java

@@ -0,0 +1,263 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test.demo;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+import java.util.Vector;
+import java.util.logging.FileHandler;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.logging.SimpleFormatter;
+
+import de.javawi.jstun.attribute.ChangeRequest;
+import de.javawi.jstun.attribute.ChangedAddress;
+import de.javawi.jstun.attribute.MappedAddress;
+import de.javawi.jstun.attribute.MessageAttributeException;
+import de.javawi.jstun.attribute.MessageAttributeParsingException;
+import de.javawi.jstun.attribute.ResponseAddress;
+import de.javawi.jstun.attribute.SourceAddress;
+import de.javawi.jstun.attribute.UnknownAttribute;
+import de.javawi.jstun.attribute.UnknownMessageAttributeException;
+import de.javawi.jstun.attribute.MessageAttributeInterface.MessageAttributeType;
+import de.javawi.jstun.header.MessageHeader;
+import de.javawi.jstun.header.MessageHeaderParsingException;
+import de.javawi.jstun.header.MessageHeaderInterface.MessageHeaderType;
+import de.javawi.jstun.util.Address;
+import de.javawi.jstun.util.UtilityException;
+
+/*
+ * This class implements a STUN server as described in RFC 3489.
+ * The server requires a machine that is dual-homed to be functional. 
+ */
+public class StunServer {
+	private static Logger logger = Logger.getLogger("de.javawi.stun.test.StunServer");
+	Vector<DatagramSocket> sockets;
+	
+	public StunServer(int primaryPort, InetAddress primary, int secondaryPort, InetAddress secondary) throws SocketException {
+		sockets = new Vector<DatagramSocket>();
+		sockets.add(new DatagramSocket(primaryPort, primary));
+		sockets.add(new DatagramSocket(secondaryPort, primary));
+		sockets.add(new DatagramSocket(primaryPort, secondary));
+		sockets.add(new DatagramSocket(secondaryPort, secondary));
+	}
+	
+	public void start() throws SocketException {
+		for (DatagramSocket socket : sockets) {
+			socket.setReceiveBufferSize(2000);
+			StunServerReceiverThread ssrt = new StunServerReceiverThread(socket);
+			ssrt.start();
+		}
+	}
+	
+	/*
+	 * Inner class to handle incoming packets and react accordingly.
+	 * I decided not to start a thread for every received Binding Request, because the time
+	 * required to receive a Binding Request, parse it, generate a Binding Response and send
+	 * it varies only between 2 and 4 milliseconds. This amount of time is small enough so
+	 * that no extra thread is needed for incoming Binding Request. 
+	 */
+	class StunServerReceiverThread extends Thread {
+		private DatagramSocket receiverSocket;
+		private DatagramSocket changedPort;
+		private DatagramSocket changedIP;
+		private DatagramSocket changedPortIP;
+		
+		StunServerReceiverThread(DatagramSocket datagramSocket) {
+			this.receiverSocket = datagramSocket;
+			for (DatagramSocket socket : sockets) {
+				if ((socket.getLocalPort() != receiverSocket.getLocalPort()) &&
+					(socket.getLocalAddress().equals(receiverSocket.getLocalAddress())))
+					changedPort = socket;
+				if ((socket.getLocalPort() == receiverSocket.getLocalPort()) &&
+					(!socket.getLocalAddress().equals(receiverSocket.getLocalAddress())))
+					changedIP = socket;
+				if ((socket.getLocalPort() != receiverSocket.getLocalPort()) &&
+					(!socket.getLocalAddress().equals(receiverSocket.getLocalAddress())))
+					changedPortIP = socket;
+			}
+		}
+		
+		public void run() {
+			while (true) {
+				try {
+					DatagramPacket receive = new DatagramPacket(new byte[200], 200);
+					receiverSocket.receive(receive);
+					logger.finest(receiverSocket.getLocalAddress().getHostAddress() + ":" + receiverSocket.getLocalPort() + " datagram received from " + receive.getAddress().getHostAddress() + ":" + receive.getPort());
+					MessageHeader receiveMH = MessageHeader.parseHeader(receive.getData()); 
+					try {
+						receiveMH.parseAttributes(receive.getData());
+						if (receiveMH.getType() == MessageHeaderType.BindingRequest) {
+							logger.config(receiverSocket.getLocalAddress().getHostAddress() + ":" + receiverSocket.getLocalPort() + " Binding Request received from " + receive.getAddress().getHostAddress() + ":" + receive.getPort());
+							ChangeRequest cr = (ChangeRequest) receiveMH.getMessageAttribute(MessageAttributeType.ChangeRequest);
+							if (cr == null) throw new MessageAttributeException("Message attribute change request is not set.");
+							ResponseAddress ra = (ResponseAddress) receiveMH.getMessageAttribute(MessageAttributeType.ResponseAddress);
+						
+							MessageHeader sendMH = new MessageHeader(MessageHeaderType.BindingResponse);
+							sendMH.setTransactionID(receiveMH.getTransactionID());
+						
+							// Mapped address attribute
+							MappedAddress ma = new MappedAddress();
+							ma.setAddress(new Address(receive.getAddress().getAddress()));
+							ma.setPort(receive.getPort());
+							sendMH.addMessageAttribute(ma);
+							// Changed address attribute
+							ChangedAddress ca = new ChangedAddress();
+							ca.setAddress(new Address(changedPortIP.getLocalAddress().getAddress()));
+							ca.setPort(changedPortIP.getLocalPort());
+							sendMH.addMessageAttribute(ca);
+							if (cr.isChangePort() && (!cr.isChangeIP())) {
+								logger.finer("Change port received in Change Request attribute");
+								// Source address attribute
+								SourceAddress sa = new SourceAddress();
+								sa.setAddress(new Address(changedPort.getLocalAddress().getAddress()));
+								sa.setPort(changedPort.getLocalPort());
+								sendMH.addMessageAttribute(sa);
+								byte[] data = sendMH.getBytes();
+								DatagramPacket send = new DatagramPacket(data, data.length);
+								if (ra != null) {
+									send.setPort(ra.getPort());
+									send.setAddress(ra.getAddress().getInetAddress());
+								} else {
+									send.setPort(receive.getPort());
+									send.setAddress(receive.getAddress());
+								}
+								changedPort.send(send);
+								logger.config(changedPort.getLocalAddress().getHostAddress() + ":" + changedPort.getLocalPort() + " send Binding Response to " + send.getAddress().getHostAddress() + ":" + send.getPort());
+							} else if ((!cr.isChangePort()) && cr.isChangeIP()) {
+								logger.finer("Change ip received in Change Request attribute");
+								// Source address attribute
+								SourceAddress sa = new SourceAddress();
+								sa.setAddress(new Address(changedIP.getLocalAddress().getAddress()));
+								sa.setPort(changedIP.getLocalPort());
+								sendMH.addMessageAttribute(sa);
+								byte[] data = sendMH.getBytes();
+								DatagramPacket send = new DatagramPacket(data, data.length);
+								if (ra != null) {
+									send.setPort(ra.getPort());
+									send.setAddress(ra.getAddress().getInetAddress());
+								} else {
+									send.setPort(receive.getPort());
+									send.setAddress(receive.getAddress());
+								}
+								changedIP.send(send);
+								logger.config(changedIP.getLocalAddress().getHostAddress() + ":" + changedIP.getLocalPort() + " send Binding Response to " + send.getAddress().getHostAddress() + ":" + send.getPort());
+							} else if ((!cr.isChangePort()) && (!cr.isChangeIP())) {
+								logger.finer("Nothing received in Change Request attribute");
+								// Source address attribute
+								SourceAddress sa = new SourceAddress();
+								sa.setAddress(new Address(receiverSocket.getLocalAddress().getAddress()));
+								sa.setPort(receiverSocket.getLocalPort());
+								sendMH.addMessageAttribute(sa);
+								byte[] data = sendMH.getBytes();
+								DatagramPacket send = new DatagramPacket(data, data.length);
+								if (ra != null) {
+									send.setPort(ra.getPort());
+									send.setAddress(ra.getAddress().getInetAddress());
+								} else {
+									send.setPort(receive.getPort());
+									send.setAddress(receive.getAddress());
+								}
+								receiverSocket.send(send);
+								logger.config(receiverSocket.getLocalAddress().getHostAddress() + ":" + receiverSocket.getLocalPort() + " send Binding Response to " + send.getAddress().getHostAddress() + ":" + send.getPort());
+							} else if (cr.isChangePort() && cr.isChangeIP()) {
+								logger.finer("Change port and ip received in Change Request attribute");
+								// Source address attribute
+								SourceAddress sa = new SourceAddress();
+								sa.setAddress(new Address(changedPortIP.getLocalAddress().getAddress()));
+								sa.setPort(changedPortIP.getLocalPort());
+								sendMH.addMessageAttribute(sa);
+								byte[] data = sendMH.getBytes();
+								DatagramPacket send = new DatagramPacket(data, data.length);
+								if (ra != null) {
+									send.setPort(ra.getPort());
+									send.setAddress(ra.getAddress().getInetAddress());
+								} else {
+									send.setPort(receive.getPort());
+									send.setAddress(receive.getAddress());
+								}
+								changedPortIP.send(send);
+								logger.config(changedPortIP.getLocalAddress().getHostAddress() + ":" + changedPortIP.getLocalPort() + " send Binding Response to " + send.getAddress().getHostAddress() + ":" + send.getPort());
+							}
+						}
+					} catch (UnknownMessageAttributeException umae) {
+						umae.printStackTrace();
+						// Generate Binding error response
+						MessageHeader sendMH = new MessageHeader(MessageHeaderType.BindingErrorResponse);
+						sendMH.setTransactionID(receiveMH.getTransactionID());
+						
+						// Unknown attributes
+						UnknownAttribute ua = new UnknownAttribute();
+						ua.addAttribute(umae.getType());
+						sendMH.addMessageAttribute(ua);
+						
+						byte[] data = sendMH.getBytes();
+						DatagramPacket send = new DatagramPacket(data, data.length);
+						send.setPort(receive.getPort());
+						send.setAddress(receive.getAddress());
+						receiverSocket.send(send);
+						logger.config(changedPortIP.getLocalAddress().getHostAddress() + ":" + changedPortIP.getLocalPort() + " send Binding Error Response to " + send.getAddress().getHostAddress() + ":" + send.getPort());
+					}	
+				} catch (IOException ioe) {
+					ioe.printStackTrace();
+				} catch (MessageAttributeParsingException mape) {
+					mape.printStackTrace();
+				} catch (MessageAttributeException mae) {
+					mae.printStackTrace();
+				} catch (MessageHeaderParsingException mhpe) {
+					mhpe.printStackTrace();
+				} catch (UtilityException ue) {
+					ue.printStackTrace();
+				} catch (ArrayIndexOutOfBoundsException aioobe) {
+					aioobe.printStackTrace();
+				}
+			}
+		}
+	}
+	
+	/*
+	 * To invoke the STUN server two IP addresses and two ports are required.
+	 */
+	public static void main(String args[]) {
+		try {
+			if (args.length != 4) {
+				System.out.println("usage: java de.javawi.jstun.test.demo.StunServer PORT1 IP1 PORT2 IP2");
+				System.out.println();
+				System.out.println(" PORT1 - the first port that should be used by the server");
+				System.out.println("   IP1 - the first ip address that should be used by the server");
+				System.out.println(" PORT2 - the second port that should be used by the server");
+				System.out.println("   IP2 - the second ip address that should be used by the server");
+				System.exit(0);
+			}
+			Handler fh = new FileHandler("logging_server.txt");
+			fh.setFormatter(new SimpleFormatter());
+			Logger.getLogger("de.javawi.stun").addHandler(fh);
+			Logger.getLogger("de.javawi.stun").setLevel(Level.ALL);
+			StunServer ss = new StunServer(Integer.parseInt(args[0]),
+										   InetAddress.getByName(args[1]),
+										   Integer.parseInt(args[2]),
+										   InetAddress.getByName(args[3]));
+			ss.start();
+		} catch (SocketException se) {
+			se.printStackTrace();
+		} catch (UnknownHostException uhe) {
+			uhe.printStackTrace();
+		} catch (IOException ioe) {
+			ioe.printStackTrace();
+		}
+	}
+}

src/de/javawi/jstun/test/demo/ice/Candidate.java

@@ -0,0 +1,115 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test.demo.ice;
+
+import java.net.DatagramSocket;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+
+import de.javawi.jstun.util.Address;
+import de.javawi.jstun.util.UtilityException;
+
+public class Candidate implements Comparable {
+	// The ieft-mmusic-ice-12 draft is not non-ambigious about the number of types.
+	// Chapter 5.1 defines 3 and 4 types on page 16 and page 17, respectively. 
+	public enum CandidateType { Local, ServerReflexive, PeerReflexive, Relayed };
+	
+	private DatagramSocket socket;
+	private CandidateType type;
+	private short componentId;
+	private int priority;
+	private int foundationId;
+	private Candidate base;
+	private boolean isInUse;
+	
+	public Candidate(Address address, short componentId) throws SocketException, UnknownHostException, UtilityException {
+		this.socket = new DatagramSocket(0, address.getInetAddress());
+		this.type = CandidateType.Local;
+		this.componentId = componentId;
+		this.priority = 0;
+		this.base = this;
+		this.isInUse = false;
+	}
+	
+	public Candidate(Address address, CandidateType type, short componentId, Candidate base) throws SocketException, UnknownHostException, UtilityException {
+		this.socket = new DatagramSocket(0, address.getInetAddress());
+		this.type = type;
+		setComponentId(componentId);
+		this.priority = 0;
+		this.base = base;
+		this.isInUse = false;
+	}
+
+	public void setBase(Candidate base) {
+		this.base = base;
+	}
+	
+	public Candidate getBase() {
+		return base;
+	}
+	
+	public CandidateType getCandidateType() {
+		return type;
+	}
+	
+	public void setComponentId(short componentId) {
+		if ((componentId < 1) || (componentId > 256)) throw new IllegalArgumentException(componentId + " is not between 1 and 256 inclusive.");
+		this.componentId = componentId;
+	}
+	
+	public short getComponentId() {
+		return componentId;
+	}
+	
+	public void setFoundationId(int foundationId) {
+		this.foundationId = foundationId;
+	}
+	
+	public int getFoundationId() {
+		return foundationId;
+	}
+	
+	public void setPriority(int priority) {
+		this.priority = priority;
+	}
+	
+	public int getPriority() {
+		return priority;
+	}
+	
+	public Address getAddress() throws UtilityException {
+		return new Address(socket.getLocalAddress().getAddress());
+	}
+
+	public int getPort() {
+		return socket.getLocalPort();
+	}
+	
+	public void setInUse(boolean isInUse) {
+		this.isInUse = isInUse;
+	}
+	
+	public boolean getInUse() {
+		return isInUse;
+	}
+	
+	public int compareTo(Object arg0) {
+		Candidate cand = (Candidate) arg0;
+		return cand.getPriority() - getPriority();
+	}
+	
+	public boolean equals(Object o) {
+		if (o == null) return false;
+		if ((((Candidate) o).socket.equals(socket)) && (((Candidate) o).base.equals(base))) return true;
+		return false;
+	}
+}

src/de/javawi/jstun/test/demo/ice/ICENegociator.java

@@ -0,0 +1,146 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.test.demo.ice;
+
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Vector;
+
+import de.javawi.jstun.test.DiscoveryInfo;
+import de.javawi.jstun.test.DiscoveryTest;
+import de.javawi.jstun.test.demo.ice.Candidate.CandidateType;
+import de.javawi.jstun.util.Address;
+
+public class ICENegociator {
+	// type preference must be an integere from 0 (=lowest) to 126 (=highest) (inclusive)
+	private final static int LOCAL_PREFERENCE = 0;
+	private final static int SERVER_REFLEXIVE_PREFERENCE = 42;
+	private final static int PEER_REFLEXIVE_PREFERENCE = 84;
+	private final static int RELAYED_PREFERENCE = 126;
+	
+	// component id
+	private short componentId;
+	
+	// candidates
+	HashSet<Candidate> candidates;
+	
+	public ICENegociator(short componentId) {
+		this.componentId = componentId;
+		candidates = new HashSet<Candidate>();
+	}
+
+	/*
+	 * This method gathers candidate addresses as described in draft-ietf-mmusic-ice-12.txt Chapter 2.1
+	 * Unfortunately, only the candidates of the direct attached network interfaces and server reflexive
+	 * addreses are gathered. So far, no support for relayed candidates is available (because I am not
+	 * aware of any STUN relay server).
+	 */
+	public void gatherCandidateAddresses() {
+		candidates = new HashSet<Candidate>();
+		try {
+			Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces();
+			while (ifaces.hasMoreElements()) {
+				NetworkInterface iface = ifaces.nextElement();
+				Enumeration<InetAddress> iaddresses = iface.getInetAddresses();
+				while (iaddresses.hasMoreElements()) {
+					InetAddress iaddress = iaddresses.nextElement();
+					if (!iaddress.isLoopbackAddress() && !iaddress.isLinkLocalAddress()) {
+						// add host candidate
+						Candidate local = new Candidate(new Address(iaddress.getAddress()), componentId);
+						candidates.add(local);
+						// add server reflexive address
+						DiscoveryTest test = new DiscoveryTest(iaddress, "iphone-stun.freenet.de", 3478);
+						DiscoveryInfo di = test.test();
+						if (di.getPublicIP() != null) {
+							Candidate cand = new Candidate(new Address(di.getPublicIP().getAddress()), CandidateType.ServerReflexive, componentId, local);
+							cand.setComponentId(componentId);
+							candidates.add(cand);
+						}
+					}
+				}
+			}
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+	
+	public void prioritizeCandidates() {
+		// count number of candidate types
+		int numberLocal = 0;
+		int numberServerReflexive = 0;
+		int numberPeerReflexive = 0;
+		int numberRelayed = 0;
+		// count number of candidates of a particular type
+		Iterator<Candidate> iterCandidates = candidates.iterator();
+		while (iterCandidates.hasNext()) {
+			Candidate cand = iterCandidates.next();
+			CandidateType type = cand.getCandidateType();
+			if (type == CandidateType.Local) numberLocal++;
+			else if (type == CandidateType.ServerReflexive) numberServerReflexive++;
+			else if (type == CandidateType.PeerReflexive) numberPeerReflexive++;
+			else if (type == CandidateType.Relayed) numberRelayed++;
+		}
+		// assign priorities
+		iterCandidates = candidates.iterator();
+		while (iterCandidates.hasNext()) {
+			int typeValue = 0;
+			int localValue = 0;
+			int componentValue = 0;
+			Candidate cand = iterCandidates.next();
+			CandidateType type = cand.getCandidateType();
+			if (type == CandidateType.Local) {
+				typeValue = LOCAL_PREFERENCE;
+				localValue = numberLocal--;
+			}
+			else if (type == CandidateType.ServerReflexive) {
+				typeValue = SERVER_REFLEXIVE_PREFERENCE;
+				localValue = numberServerReflexive--;
+			}
+			else if (type == CandidateType.PeerReflexive) {
+				typeValue = PEER_REFLEXIVE_PREFERENCE;
+				localValue = numberPeerReflexive--;
+			}
+			else if (type == CandidateType.Relayed) {
+				typeValue = RELAYED_PREFERENCE;
+				localValue = numberRelayed--;
+			}
+			componentValue = cand.getComponentId();
+			int priority = ((2 ^ 24) * typeValue) + ((2 ^ 8) * localValue) + componentValue;
+			cand.setPriority(priority);
+		}
+	}
+	
+	public List<Candidate> getSortedCandidates() {
+		Vector<Candidate> sortedCandidates = new Vector<Candidate>(candidates);
+		Collections.sort(sortedCandidates);
+		return sortedCandidates;
+	}
+
+	public static void main(String args[]) {
+		ICENegociator cc = new ICENegociator((short) 1);
+		// gather candidates
+		cc.gatherCandidateAddresses();
+		// priorize candidates
+		cc.prioritizeCandidates();
+		// get SortedCandidates
+		List<Candidate> sortedCandidates = cc.getSortedCandidates();
+		
+		// sent sorted candidate addresses to peer over SDP
+		// received sorted candidate addresses of peer over SDP
+		
+	}
+}

src/de/javawi/jstun/util/Address.java

@@ -0,0 +1,102 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.util;
+
+import java.util.*;
+import java.net.*;
+
+public class Address {
+	int firstOctet;
+	int secondOctet;
+	int thirdOctet;
+	int fourthOctet;
+	
+	public Address(int firstOctet, int secondOctet, int thirdOctet, int fourthOctet) throws UtilityException {
+		if ((firstOctet < 0) || (firstOctet > 255) || (secondOctet < 0) || (secondOctet > 255) || (thirdOctet < 0) || (thirdOctet > 255) || (fourthOctet < 0) || (fourthOctet > 255)) {
+			throw new UtilityException("Address is malformed.");
+		}
+		this.firstOctet = firstOctet;
+		this.secondOctet = secondOctet;
+		this.thirdOctet = thirdOctet;
+		this.fourthOctet = fourthOctet;
+	}
+	
+	public Address(String address) throws UtilityException {
+		StringTokenizer st = new StringTokenizer(address, ".");
+		if (st.countTokens() != 4) {
+			throw new UtilityException("4 octets in address string are required.");
+		}
+		int i = 0;
+		while (st.hasMoreTokens()) {
+			int temp = Integer.parseInt(st.nextToken());
+			if ((temp < 0) || (temp > 255)) {
+				throw new UtilityException("Address is in incorrect format.");
+			}
+			switch (i) {
+			case 0: firstOctet = temp; ++i; break;
+			case 1: secondOctet = temp; ++i; break;
+			case 2: thirdOctet = temp; ++i; break;
+			case 3: fourthOctet = temp; ++i; break;
+			}
+		}
+	}
+	
+	public Address(byte[] address) throws UtilityException {
+		if (address.length < 4) {
+			throw new UtilityException("4 bytes are required.");
+		}
+		firstOctet = Utility.oneByteToInteger(address[0]);
+		secondOctet = Utility.oneByteToInteger(address[1]);
+		thirdOctet = Utility.oneByteToInteger(address[2]);
+		fourthOctet = Utility.oneByteToInteger(address[3]);
+	}
+	
+	public String toString() {
+		return firstOctet + "." + secondOctet + "." + thirdOctet + "." + fourthOctet;
+	}
+	
+	public byte[] getBytes() throws UtilityException {
+		byte[] result = new byte[4];
+		result[0] = Utility.integerToOneByte(firstOctet);
+		result[1] = Utility.integerToOneByte(secondOctet);
+		result[2] = Utility.integerToOneByte(thirdOctet);
+		result[3] = Utility.integerToOneByte(fourthOctet);
+		return result;
+	}
+	
+	public InetAddress getInetAddress() throws UtilityException, UnknownHostException {
+		byte[] address = new byte[4];
+		address[0] = Utility.integerToOneByte(firstOctet);
+		address[1] = Utility.integerToOneByte(secondOctet);
+		address[2] = Utility.integerToOneByte(thirdOctet);
+		address[3] = Utility.integerToOneByte(fourthOctet);
+		return InetAddress.getByAddress(address);
+	}
+	
+	public boolean equals(Object obj) {
+		if (obj == null) return false;
+		try {
+			byte[] data1 = this.getBytes();
+			byte[] data2 = ((Address) obj).getBytes();
+			if ((data1[0] == data2[0]) && (data1[1] == data2[1]) &&
+			    (data1[2] == data2[2]) && (data1[3] == data2[3])) return true;
+			return false;
+		} catch (UtilityException ue) {
+			return false;
+		}
+	}
+	
+	public int hashCode() {
+		return (firstOctet << 24) + (secondOctet << 16) + (thirdOctet << 8) + fourthOctet; 
+	}
+
+}

src/de/javawi/jstun/util/Utility.java

@@ -0,0 +1,68 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.util;
+
+public class Utility {
+
+	public static final byte integerToOneByte(int value) throws UtilityException {
+		if ((value > Math.pow(2,15)) || (value < 0)) {
+			throw new UtilityException("Integer value " + value + " is larger than 2^15");
+		}
+		return (byte)(value & 0xFF);
+	}
+	
+	public static final byte[] integerToTwoBytes(int value) throws UtilityException {
+		byte[] result = new byte[2];
+		if ((value > Math.pow(2,31)) || (value < 0)) {
+			throw new UtilityException("Integer value " + value + " is larger than 2^31");
+		}
+        result[0] = (byte)((value >>> 8) & 0xFF);
+        result[1] = (byte)(value & 0xFF);
+		return result; 
+	}
+	
+	public static final byte[] integerToFourBytes(int value) throws UtilityException {
+		byte[] result = new byte[4];
+		if ((value > Math.pow(2,63)) || (value < 0)) {
+			throw new UtilityException("Integer value " + value + " is larger than 2^63");
+		}
+        result[0] = (byte)((value >>> 24) & 0xFF);
+		result[1] = (byte)((value >>> 16) & 0xFF);
+		result[2] = (byte)((value >>> 8) & 0xFF);
+        result[3] = (byte)(value & 0xFF);
+		return result; 
+	}
+	
+	public static final int oneByteToInteger(byte value) throws UtilityException {
+		return (int)value & 0xFF;
+	}
+	
+	public static final int twoBytesToInteger(byte[] value) throws UtilityException {
+		if (value.length < 2) {
+			throw new UtilityException("Byte array too short!");
+		}
+        int temp0 = value[0] & 0xFF;
+        int temp1 = value[1] & 0xFF;
+        return ((temp0 << 8) + temp1);
+	}
+	
+	public static final long fourBytesToLong(byte[] value) throws UtilityException {
+		if (value.length < 4) {
+			throw new UtilityException("Byte array too short!");
+		}
+        int temp0 = value[0] & 0xFF;
+        int temp1 = value[1] & 0xFF;
+		int temp2 = value[2] & 0xFF;
+		int temp3 = value[3] & 0xFF;
+        return (((long)temp0 << 24) + (temp1 << 16) + (temp2 << 8) + temp3);
+	}	                                      
+}

src/de/javawi/jstun/util/UtilityException.java

@@ -0,0 +1,21 @@
+/*
+ * This file is part of JSTUN. 
+ * 
+ * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
+ * reserved.
+ * 
+ * This software is licensed under either the GNU Public License (GPL),
+ * or the Apache 2.0 license. Copies of both license agreements are
+ * included in this distribution.
+ */
+
+package de.javawi.jstun.util;
+
+public class UtilityException extends Exception {
+	private static final long serialVersionUID = 3545800974716581680L;
+
+	UtilityException(String mesg) {
+		super(mesg);
+	}
+
+}