...

.gitignore

@@ -0,0 +1,4 @@
+build/
+.gradle/
+.idea/
+app/lib/

README.MD

@@ -0,0 +1,11 @@
+# PokeMMO Packet Editor
+## How to Use
+1. Download the latest release from the releases page. 
+2. Edit your Hosts file to redirect the PokeMMO server to your local machine.
+```
+127.0.0.1     loginserver.pokemmo.com
+```
+3. Run PokeMMO by clicking Game -> Start
+4. Start the proxy by clicking Start Server
+
+You can now use the client normally and the proxy will intercept all packets sent to the server.

agent/build.gradle

@@ -0,0 +1,51 @@
+plugins {
+    id 'java'
+    id 'com.github.johnrengelman.shadow' version '8.1.1'
+}
+
+group = 'de.fiereu'
+
+repositories {
+    mavenCentral()
+}
+
+shadowJar {
+    archiveBaseName.set('agent')
+    archiveClassifier.set('')
+    archiveVersion.set('')
+
+    manifest {
+        attributes(
+            'Premain-Class': 'de.fiereu.ppe.agent.Agent'
+        )
+    }
+}
+
+dependencies {
+    testImplementation platform('org.junit:junit-bom:5.10.0')
+    testImplementation 'org.junit.jupiter:junit-jupiter'
+
+    implementation project(':certs')
+
+    // ASM
+    implementation 'org.ow2.asm:asm:9.7'
+    implementation 'org.ow2.asm:asm-commons:9.7'
+}
+
+test {
+    useJUnitPlatform()
+}
+
+jar {
+    manifest {
+        attributes(
+            'Premain-Class': 'de.fiereu.ppe.agent.Agent'
+        )
+    }
+}
+
+shadowJar {
+    archiveBaseName.set('agent')
+    archiveClassifier.set('')
+    archiveVersion.set('')
+}

agent/src/main/java/de/fiereu/ppe/agent/Agent.java

@@ -0,0 +1,14 @@
+package de.fiereu.ppe.agent;
+
+import java.lang.instrument.Instrumentation;
+
+public class Agent {
+
+  private static Instrumentation instrumentation;
+
+  public static void premain(String args, Instrumentation inst) {
+    instrumentation = inst;
+    instrumentation.addTransformer(new PpeClassFileTransformer());
+  }
+
+}

agent/src/main/java/de/fiereu/ppe/agent/CertificatePatch.java

@@ -0,0 +1,38 @@
+package de.fiereu.ppe.agent;
+
+import de.fiereu.ppe.pokemmo.Certificates;
+import java.util.List;
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.MethodVisitor;
+
+public class CertificatePatch extends ClassVisitor {
+
+  private static final List<String> certificates = List.of(
+      Certificates.lsPubKey,
+      Certificates.gsPubKey,
+      Certificates.csPubKey
+  );
+
+  CertificatePatch(int api, ClassVisitor classVisitor) {
+    super(api, classVisitor);
+  }
+
+  @Override
+  public MethodVisitor visitMethod(int access, String name, String descriptor, String signature,
+      String[] exceptions) {
+    return new MethodVisitor(api,
+        super.visitMethod(access, name, descriptor, signature, exceptions)) {
+      @Override
+      public void visitLdcInsn(Object value) {
+        if (value instanceof String str) {
+          if (certificates.contains(str)) {
+            super.visitLdcInsn(Certificates.proxyPubKey);
+            System.out.printf("Patched certificate: %s -> %s%n", str, Certificates.proxyPubKey);
+            return;
+          }
+        }
+        super.visitLdcInsn(value);
+      }
+    };
+  }
+}

agent/src/main/java/de/fiereu/ppe/agent/PpeClassFileTransformer.java

@@ -0,0 +1,26 @@
+package de.fiereu.ppe.agent;
+
+import java.lang.instrument.ClassFileTransformer;
+import java.security.ProtectionDomain;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.Opcodes;
+
+public class PpeClassFileTransformer implements ClassFileTransformer {
+
+  @Override
+  public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
+      ProtectionDomain protectionDomain, byte[] classfileBuffer) {
+    try {
+      ClassReader classReader = new ClassReader(classfileBuffer);
+      ClassWriter classWriter = new ClassWriter(classReader, 0);
+      ClassVisitor classVisitor = new CertificatePatch(Opcodes.ASM9, classWriter);
+      classReader.accept(classVisitor, 0);
+      return classWriter.toByteArray();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+    return classfileBuffer;
+  }
+}

app/build.gradle

@@ -0,0 +1,58 @@
+plugins {
+    id 'java'
+    id 'com.github.johnrengelman.shadow' version '8.1.1'
+}
+
+group = 'de.fiereu'
+version = '1.0'
+
+shadowJar {
+    archiveBaseName.set('app')
+    archiveClassifier.set('')
+    archiveVersion.set('')
+
+    manifest {
+        attributes(
+                'Main-Class': 'de.fiereu.ppe.Application'
+        )
+    }
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation platform('org.junit:junit-bom:5.9.1')
+    testImplementation 'org.junit.jupiter:junit-jupiter'
+
+    implementation project(':certs')
+
+    // logback + slf4j
+    implementation 'org.slf4j:slf4j-api:1.7.32'
+    implementation 'ch.qos.logback:logback-classic:1.4.14'
+
+    // FlatDev
+    implementation 'com.formdev:flatlaf:3.4.1'
+    implementation 'com.formdev:flatlaf-intellij-themes:3.4.1'
+
+    // MigLayout
+    implementation 'com.miglayout:miglayout-swing:11.3'
+
+    // BouncyCastle
+    implementation 'org.bouncycastle:bcprov-jdk18on:1.78.1'
+
+    implementation 'com.github.maltalex:ineter:0.3.0'
+
+    implementation 'org.xerial:sqlite-jdbc:3.45.3.0'
+
+    implementation 'commons-beanutils:commons-beanutils:1.9.4'
+    implementation 'org.apache.commons:commons-configuration2:2.10.1'
+
+    implementation 'org.exbin.bined:bined-swing:0.2.1'
+    implementation 'org.exbin.auxiliary:binary_data:0.2.1'
+}
+
+test {
+    useJUnitPlatform()
+}

app/src/main/java/de/fiereu/ppe/Application.java

@@ -0,0 +1,71 @@
+package de.fiereu.ppe;
+
+import de.fiereu.ppe.forms.MainForm;
+import com.formdev.flatlaf.intellijthemes.materialthemeuilite.FlatMaterialDarkerIJTheme;
+import java.io.File;
+import java.io.IOException;
+import java.sql.SQLException;
+import org.apache.commons.configuration2.Configuration;
+import org.apache.commons.configuration2.builder.fluent.Configurations;
+import org.apache.commons.configuration2.builder.fluent.Parameters;
+import org.apache.commons.configuration2.ex.ConfigurationException;
+
+public class Application {
+
+  private static final String SQLITE_DB = "packets.db";
+  private static final String CONFIG_FILE = "config.conf";
+
+  public static void main(String[] args) {
+    try {
+      FlatMaterialDarkerIJTheme.setup();
+    } catch (Exception e) {
+      ErrorHandler.handle(null, "Could not set Look&Feel.", e);
+    }
+
+    Configuration config = null;
+    try {
+      config = loadConfig();
+    } catch (ConfigurationException e) {
+      ErrorHandler.handle(null, "Could not load configuration.", e);
+      return;
+    } catch (IOException e) {
+      ErrorHandler.handle(null, "Could not create configuration file.", e);
+      return;
+    }
+    PacketHistory packetHistory;
+    try {
+      packetHistory = loadPacketHistory();
+    } catch (IOException | SQLException e) {
+      ErrorHandler.handle(null, "Could not load PacketHistory.", e);
+      return;
+    }
+    new MainForm(config, packetHistory).setVisible(true);
+  }
+
+  private static Configuration loadConfig() throws ConfigurationException, IOException {
+    File file = new File(CONFIG_FILE);
+    if (!file.exists()) {
+      if (!file.createNewFile()) {
+        throw new IOException("Could not create configuration file.");
+      }
+    }
+    Configurations configs = new Configurations();
+    var builder = configs.propertiesBuilder().configure(
+        new Parameters().fileBased()
+            .setFile(new File(CONFIG_FILE))
+            .setThrowExceptionOnMissing(false)
+    );
+    builder.setAutoSave(true);
+    return builder.getConfiguration();
+  }
+
+  private static PacketHistory loadPacketHistory() throws IOException, SQLException {
+    File sqliteDB = new File(SQLITE_DB);
+    if (!sqliteDB.exists()) {
+      if(!sqliteDB.createNewFile()) {
+        throw new IOException("Could not create SQLite database.");
+      }
+    }
+    return new PacketHistory(new File(SQLITE_DB));
+  }
+}

app/src/main/java/de/fiereu/ppe/ErrorHandler.java

@@ -0,0 +1,21 @@
+package de.fiereu.ppe;
+
+import java.awt.Component;
+import javax.swing.JOptionPane;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ErrorHandler {
+
+  public static final Logger log = LoggerFactory.getLogger(ErrorHandler.class);
+
+  public static void handle(Component parent, String message, Throwable t) {
+    log.error(message, t);
+    JOptionPane.showMessageDialog(parent, t.getMessage(), message, JOptionPane.ERROR_MESSAGE);
+  }
+
+  public static void handle(Component parent, String message) {
+    log.error(message);
+    JOptionPane.showMessageDialog(parent, message, "Error", JOptionPane.ERROR_MESSAGE);
+  }
+}