Added IP -> I2P URL mapping support to SOCKS client tunnels

To use, add custom options to the SOCKS client tunnel like:

ipmapping.127.12.12.12=stats.i2p

Then save and restart the tunnel.

apps/i2ptunnel/java/src/net/i2p/i2ptunnel/socks/SOCKS4aServer.java

@@ -46,9 +46,11 @@ public class SOCKS4aServer extends SOCKSServer {
      * client socket.
      *
      * @param clientSock client socket
+     * @param props non-null
      */
-    public SOCKS4aServer(Socket clientSock) {
+    public SOCKS4aServer(Socket clientSock, Properties props) {
         this.clientSock = clientSock;
+        this.props = props;
     }
 
     public Socket getClientSocket() throws SOCKSException {
@@ -116,6 +118,13 @@ public class SOCKS4aServer extends SOCKSServer {
             }
         }
 
+        // Check if the requested IP should be mapped to a .i2p URL
+        String mappedUrl = getMappedUrlForIP(connHostName);
+        if (mappedUrl != null && mappedUrl.toLowerCase(Locale.US).endsWith(".i2p")) {
+            _log.debug("IPV4 address " + connHostName + " was mapped to URL " + mappedUrl);
+            connHostName = mappedUrl;
+        }
+
         // discard user name
         readString(in);
 

apps/i2ptunnel/java/src/net/i2p/i2ptunnel/socks/SOCKS5Server.java

@@ -42,7 +42,6 @@ public class SOCKS5Server extends SOCKSServer {
     private static final int SOCKS_VERSION_5 = 0x05;
 
     private final Socket clientSock;
-    private final Properties props;
     private boolean setupCompleted = false;
     private final boolean authRequired;
 
@@ -207,7 +206,12 @@ public class SOCKS5Server extends SOCKSServer {
                     connHostName += ".";
                 }
             }
-            if (command != Command.UDP_ASSOCIATE)
+            // Check if the requested IP should be mapped to a .i2p URL
+            String mappedUrl = getMappedUrlForIP(connHostName);
+            if (mappedUrl != null && mappedUrl.toLowerCase(Locale.US).endsWith(".i2p")) {
+                _log.debug("IPV4 address " + connHostName + " was mapped to URL " + mappedUrl);
+                connHostName = mappedUrl;
+            } else if (command != Command.UDP_ASSOCIATE)
                 _log.warn("IPV4 address type in request: " + connHostName + ". Is your client secure?");
             break;
         case AddressType.DOMAINNAME:

apps/i2ptunnel/java/src/net/i2p/i2ptunnel/socks/SOCKSServer.java

@@ -7,6 +7,7 @@
 package net.i2p.i2ptunnel.socks;
 
 import java.net.Socket;
+import java.util.Properties;
 
 import net.i2p.client.streaming.I2PSocket;
 import net.i2p.util.Log;
@@ -19,11 +20,29 @@ import net.i2p.util.Log;
 public abstract class SOCKSServer {
     private static final Log _log = new Log(SOCKSServer.class);
 
+    private static final String PROP_MAPPING_PREFIX = "ipmapping.";
+
     /* Details about the connection requested by client */
     protected String connHostName;
     protected int connPort;
     protected int addressType;
 
+    protected Properties props;
+
+    /**
+     * IP to I2P URL mapping support. This matches the given IP string against
+     * a user-set list of mappings. This enables applications which do not
+     * properly support the SOCKS5 DOMAINNAME feature to be used with I2P.
+     * @param ip The IP address to check.
+     * @return   The I2P URL if a mapping is found, or null otherwise.
+     * @since 0.9.5
+     */
+    protected String getMappedUrlForIP(String ip) {
+        if (props.containsKey(PROP_MAPPING_PREFIX + ip))
+            return props.getProperty(PROP_MAPPING_PREFIX + ip);
+        return null;
+    }
+
     /**
      * Perform server initialization (expecially regarding protected
      * variables).

apps/i2ptunnel/java/src/net/i2p/i2ptunnel/socks/SOCKSServerFactory.java

@@ -54,7 +54,7 @@ public class SOCKSServerFactory {
                     props.containsKey(I2PTunnelHTTPClientBase.PROP_PW)) {
                     throw new SOCKSException("SOCKS 4/4a not supported when authorization is required");
                 }
-                serv = new SOCKS4aServer(s);
+                serv = new SOCKS4aServer(s, props);
                 break;
             case 0x05:
                 // SOCKS version 5