add config file

Signed-off-by: pengzhile <pengzhile@gmail.com>

src/main/java/io/zhile/research/ja/netfilter/Launcher.java

@@ -1,5 +1,11 @@
 package io.zhile.research.ja.netfilter;
 
+import io.zhile.research.ja.netfilter.commons.ConfigDetector;
+import io.zhile.research.ja.netfilter.commons.ConfigParser;
+import io.zhile.research.ja.netfilter.commons.DebugInfo;
+import io.zhile.research.ja.netfilter.models.FilterConfig;
+
+import java.io.File;
 import java.lang.instrument.Instrumentation;
 import java.lang.instrument.UnmodifiableClassException;
 import java.net.MalformedURLException;
@@ -25,6 +31,19 @@ public class Launcher {
             throw new RuntimeException("Can not access ja-netfilter jar file.", e);
         }
 
+        File configFile = ConfigDetector.detect(new File(jarURL.getPath()).getParentFile().getPath(), args);
+        if (null == configFile) {
+            DebugInfo.output("Could not find any configuration files.");
+        } else {
+            DebugInfo.output("Current config file: " + configFile.getPath());
+        }
+
+        try {
+            FilterConfig.setCurrent(new FilterConfig(ConfigParser.parse(configFile)));
+        } catch (Exception e) {
+            DebugInfo.output(e.getMessage());
+        }
+
         for (Class<?> c : inst.getAllLoadedClasses()) {
             try {
                 inst.retransformClasses(c);

src/main/java/io/zhile/research/ja/netfilter/TransformDispatcher.java

@@ -34,7 +34,7 @@ public class TransformDispatcher implements ClassFileTransformer {
             try {
                 return transformer.transform(className, classFileBuffer);
             } catch (Exception e) {
-                DebugInfo.output("=== Transform class failed: " + e.getMessage());
+                DebugInfo.output("Transform class failed: " + e.getMessage());
             }
         } while (false);
 

src/main/java/io/zhile/research/ja/netfilter/commons/ConfigDetector.java

@@ -0,0 +1,89 @@
+package io.zhile.research.ja.netfilter.commons;
+
+import io.zhile.research.ja.netfilter.utils.StringUtils;
+
+import java.io.File;
+
+public class ConfigDetector {
+    private static final String CONFIG_FILENAME = "janf_config.txt";
+
+    public static File detect(String currentDirectory, String args) {
+        File configFile = tryFile(args);        // by javaagent argument
+
+        if (null == configFile) {
+            configFile = tryFile(System.getenv("JANF_CONFIG")); // by env
+        }
+
+        if (null == configFile) {
+            configFile = tryFile(System.getProperty("janf.config"));    // by -D argument
+        }
+
+        if (null == configFile) {
+            configFile = searchDirectory(currentDirectory); // in the same dir as the jar
+        }
+
+        String userHome = System.getProperty("user.home");
+        if (null == configFile) {
+            configFile = searchDirectory(userHome, "." + CONFIG_FILENAME);  // $HOME/.janf_config.txt
+        }
+
+        if (null == configFile) {
+            configFile = searchDirectory(userHome + File.pathSeparator + ".config");    // $HOME/.config/janf_config.txt
+        }
+
+        if (null == configFile) {
+            configFile = searchDirectory(userHome + File.pathSeparator + ".local" + File.pathSeparator + "/etc");   // $HOME/.local/etc/janf_config.txt
+        }
+
+        if (null == configFile) {
+            configFile = searchDirectory("/usr/local/etc");     // /usr/local/etc/janf_config.txt
+        }
+
+        if (null == configFile) {
+            configFile = searchDirectory("/etc");               // /etc/janf_config.txt
+        }
+
+        return configFile;
+    }
+
+    private static File searchDirectory(String dirPath) {
+        return searchDirectory(dirPath, CONFIG_FILENAME);
+    }
+
+    private static File searchDirectory(String dirPath, String filename) {
+        if (StringUtils.isEmpty(dirPath)) {
+            return null;
+        }
+
+        File dirFile = new File(dirPath);
+        if (!dirFile.isDirectory()) {
+            return null;
+        }
+
+        return tryFile(new File(dirFile, filename));
+    }
+
+    private static File tryFile(String filePath) {
+        if (StringUtils.isEmpty(filePath)) {
+            return null;
+        }
+
+        return tryFile(new File(filePath));
+    }
+
+    private static File tryFile(File file) {
+        if (!file.exists()) {
+            return null;
+        }
+
+        if (!file.isFile()) {
+            return null;
+        }
+
+        if (!file.canRead()) {
+            return null;
+        }
+
+        return file;
+    }
+}

src/main/java/io/zhile/research/ja/netfilter/commons/ConfigParser.java

@@ -0,0 +1,90 @@
+package io.zhile.research.ja.netfilter.commons;
+
+import io.zhile.research.ja.netfilter.models.FilterRule;
+import io.zhile.research.ja.netfilter.utils.StringUtils;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class ConfigParser {
+    public static Map<String, List<FilterRule>> parse(File file) throws Exception {
+        Map<String, List<FilterRule>> map = new HashMap<>();
+
+        if (null == file) {
+            return map;
+        }
+
+        try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
+            int lineNumber = 0;
+            String line, lastSection = null;
+
+            while (null != (line = reader.readLine())) {
+                lineNumber++;
+                line = line.trim();
+                if (StringUtils.isEmpty(line)) {
+                    continue;
+                }
+
+                int len = line.length();
+                switch (line.charAt(0)) {
+                    case '[':
+                        if (']' != line.charAt(len - 1)) {
+                            throw new Exception("Invalid section! Line: " + lineNumber);
+                        }
+
+                        String section = line.substring(1, len - 1);
+                        if (StringUtils.isEmpty(section)) {
+                            throw new Exception("Empty section name! Line: " + lineNumber);
+                        }
+
+                        lastSection = section;
+                        map.put(lastSection, new ArrayList<>());
+                        break;
+                    case '#':
+                    case ';':
+                        break;  // comment
+                    case '/':
+                        if (len > 1 && '/' == line.charAt(1)) {
+                            break;  // comment
+                        }
+                        throw new Exception("Invalid character! Line: " + lineNumber);
+                    default:
+                        if (null == lastSection) {
+                            break;  // ignore rules without section
+                        }
+
+                        String[] parts = line.split(",", 2);
+                        if (2 != parts.length) {
+                            throw new Exception("Invalid rule! Line: " + lineNumber);
+                        }
+
+                        String type = parts[0].trim();
+                        String content = parts[1].trim();
+                        if (StringUtils.isEmpty(type) || StringUtils.isEmpty(content)) {
+                            throw new Exception("Invalid rule! Line: " + lineNumber);
+                        }
+
+                        if (!Character.isAlphabetic(type.charAt(0))) {
+                            throw new Exception("Invalid rule! Line: " + lineNumber);
+                        }
+
+                        FilterRule rule = FilterRule.of(type, content);
+                        if (null == rule) {
+                            throw new Exception("Invalid rule type! Line: " + lineNumber);
+                        }
+
+                        map.get(lastSection).add(rule);
+                        DebugInfo.output("Add section: " + lastSection + ", rule: " + rule);
+                        break;
+                }
+            }
+        }
+
+        return map;
+    }
+}

src/main/java/io/zhile/research/ja/netfilter/filters/DNSFilter.java

@@ -1,33 +1,26 @@
 package io.zhile.research.ja.netfilter.filters;
 
 import io.zhile.research.ja.netfilter.commons.DebugInfo;
-import io.zhile.research.ja.netfilter.enums.RuleType;
+import io.zhile.research.ja.netfilter.models.FilterConfig;
 import io.zhile.research.ja.netfilter.models.FilterRule;
 
 import java.io.IOException;
 import java.net.InetAddress;
-import java.util.ArrayList;
-import java.util.List;
 
 public class DNSFilter {
-    public static final List<FilterRule> RULES;
-
-    static {
-        RULES = new ArrayList<>();      // TODO read from config file
-        RULES.add(new FilterRule(RuleType.REGEXP, ".*?zhile.io"));
-    }
+    private static final String SECTION_NAME = "DNS";
 
     public static String testQuery(String host) throws IOException {
         if (null == host) {
             return null;
         }
 
-        for (FilterRule rule : RULES) {
+        for (FilterRule rule : FilterConfig.getBySection(SECTION_NAME)) {
             if (!rule.test(host)) {
                 continue;
             }
 
-            DebugInfo.output("=== reject dns query: " + host + ", rule: " + rule);
+            DebugInfo.output("Reject dns query: " + host + ", rule: " + rule);
             throw new java.net.UnknownHostException();
         }
 
@@ -39,12 +32,12 @@ public class DNSFilter {
             return null;
         }
 
-        for (FilterRule rule : RULES) {
+        for (FilterRule rule : FilterConfig.getBySection(SECTION_NAME)) {
             if (!rule.test(n.getHostName())) {
                 continue;
             }
 
-            DebugInfo.output("=== reject dns reachable test: " + n.getHostName() + ", rule: " + rule);
+            DebugInfo.output("Reject dns reachable test: " + n.getHostName() + ", rule: " + rule);
             return false;
         }
 

src/main/java/io/zhile/research/ja/netfilter/filters/URLFilter.java

@@ -1,34 +1,27 @@
 package io.zhile.research.ja.netfilter.filters;
 
 import io.zhile.research.ja.netfilter.commons.DebugInfo;
-import io.zhile.research.ja.netfilter.enums.RuleType;
+import io.zhile.research.ja.netfilter.models.FilterConfig;
 import io.zhile.research.ja.netfilter.models.FilterRule;
 
 import java.io.IOException;
 import java.net.SocketTimeoutException;
 import java.net.URL;
-import java.util.ArrayList;
-import java.util.List;
 
 public class URLFilter {
-    public static final List<FilterRule> RULES;
-
-    static {
-        RULES = new ArrayList<>();      // TODO read from config file
-        RULES.add(new FilterRule(RuleType.PREFIX, "https://zhile.io"));
-    }
+    public static final String SECTION_NAME = "URL";
 
     public static URL testURL(URL url) throws IOException {
         if (null == url) {
             return null;
         }
 
-        for (FilterRule rule : RULES) {
+        for (FilterRule rule : FilterConfig.getBySection(SECTION_NAME)) {
             if (!rule.test(url.toString())) {
                 continue;
             }
 
-            DebugInfo.output("=== reject url: " + url + ", rule: " + rule);
+            DebugInfo.output("Reject url: " + url + ", rule: " + rule);
             throw new SocketTimeoutException("connect timed out");
         }
 

src/main/java/io/zhile/research/ja/netfilter/models/FilterConfig.java

@@ -0,0 +1,44 @@
+package io.zhile.research.ja.netfilter.models;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+public class FilterConfig {
+    private static FilterConfig current;
+
+    private final Map<String, List<FilterRule>> data;
+
+    public FilterConfig(Map<String, List<FilterRule>> data) {
+        this.data = data;
+    }
+
+    public static FilterConfig getCurrent() {
+        return current;
+    }
+
+    public static void setCurrent(FilterConfig current) {
+        FilterConfig.current = current;
+    }
+
+    public static List<FilterRule> getBySection(String section) {
+        do {
+            if (null == current) {
+                break;
+            }
+
+            if (null == current.data) {
+                break;
+            }
+
+            List<FilterRule> list = current.data.get(section);
+            if (null == list) {
+                break;
+            }
+
+            return list;
+        } while (false);
+
+        return new ArrayList<>();
+    }
+}

src/main/java/io/zhile/research/ja/netfilter/models/FilterRule.java

@@ -2,9 +2,21 @@ package io.zhile.research.ja.netfilter.models;
 
 import io.zhile.research.ja.netfilter.enums.RuleType;
 
+import java.util.HashMap;
+import java.util.Map;
+
 public class FilterRule {
-    private RuleType type;
+    private static final Map<String, RuleType> SUPPORTED_TYPE_MAP;
+
+    static {
+        SUPPORTED_TYPE_MAP = new HashMap<>();
+
+        for (RuleType ruleType : RuleType.values()) {
+            SUPPORTED_TYPE_MAP.put(ruleType.name(), ruleType);
+        }
+    }
 
+    private RuleType type;
     private String rule;
 
     public FilterRule(RuleType type, String rule) {
@@ -12,6 +24,15 @@ public class FilterRule {
         this.rule = rule;
     }
 
+    public static FilterRule of(String typeStr, String content) {
+        RuleType type = SUPPORTED_TYPE_MAP.get(typeStr.toUpperCase());
+        if (null == type) {
+            return null;
+        }
+
+        return new FilterRule(type, content);
+    }
+
     public RuleType getType() {
         return type;
     }

src/main/java/io/zhile/research/ja/netfilter/utils/StringUtils.java

@@ -0,0 +1,7 @@
+package io.zhile.research.ja.netfilter.utils;
+
+public class StringUtils {
+    public static boolean isEmpty(String str) {
+        return null == str || str.isEmpty();
+    }
+}