* Streaming: Enforce a minimum MTU of 512

apps/streaming/java/src/net/i2p/client/streaming/ConnectionOptions.java

@@ -162,6 +162,7 @@ public class ConnectionOptions extends I2PSocketOptionsImpl {
      *
      */
     public static final int DEFAULT_MAX_MESSAGE_SIZE = 1730;
+    public static final int MIN_MESSAGE_SIZE = 512;
 
     public ConnectionOptions() {
         super();
@@ -389,7 +390,7 @@ public class ConnectionOptions extends I2PSocketOptionsImpl {
      * @return Maximum message size (MTU/MRU)
      */
     public int getMaxMessageSize() { return _maxMessageSize; }
-    public void setMaxMessageSize(int bytes) { _maxMessageSize = bytes; }
+    public void setMaxMessageSize(int bytes) { _maxMessageSize = Math.max(bytes, MIN_MESSAGE_SIZE); }
     
     /** 
      * how long we want to wait before any data is transferred on the

apps/streaming/java/src/net/i2p/client/streaming/ConnectionPacketHandler.java

@@ -67,12 +67,17 @@ public class ConnectionPacketHandler {
         }
 
         if (packet.isFlagSet(Packet.FLAG_MAX_PACKET_SIZE_INCLUDED)) {
-            if (packet.getOptionalMaxSize() < con.getOptions().getMaxMessageSize()) {
+            int size = packet.getOptionalMaxSize();
+            if (size < ConnectionOptions.MIN_MESSAGE_SIZE) {
+                // log.error? connection reset?
+                size = ConnectionOptions.MIN_MESSAGE_SIZE;
+            }
+            if (size < con.getOptions().getMaxMessageSize()) {
                 if (_log.shouldLog(Log.INFO))
-                    _log.info("Reducing our max message size to " + packet.getOptionalMaxSize() 
+                    _log.info("Reducing our max message size to " + size 
                               + " from " + con.getOptions().getMaxMessageSize());
-                con.getOptions().setMaxMessageSize(packet.getOptionalMaxSize());
-                con.getOutputStream().setBufferSize(packet.getOptionalMaxSize());
+                con.getOptions().setMaxMessageSize(size);
+                con.getOutputStream().setBufferSize(size);
             }
         }