I2CP: Add API method to get router version

core/java/src/net/i2p/client/I2PSession.java

@@ -443,6 +443,14 @@ public interface I2PSession {
      */
     public void sendBlindingInfo(BlindData bd) throws I2PSessionException;
 
+    /**
+     *  Always valid in RouterContext. Returns null if not yet connected in I2PAppContext.
+     *
+     *  @return null if unknown
+     *  @since 0.9.46
+     */
+    public String getRouterVersion();
+
     /**
      *  Listen on specified protocol and port.
      *

core/java/src/net/i2p/client/impl/I2PSessionImpl.java

@@ -145,6 +145,7 @@ public abstract class I2PSessionImpl implements I2PSession, I2CPMessageReader.I2
     private final AtomicInteger _lookupID = new AtomicInteger();
     protected final Object _bwReceivedLock = new Object();
     protected volatile int[] _bwLimits;
+    private volatile String _routerVersion;
     
     protected final I2PClientMessageHandlerMap _handlerMap;
     
@@ -227,6 +228,7 @@ public abstract class I2PSessionImpl implements I2PSession, I2CPMessageReader.I2
 
     /** @param routerVersion as rcvd in the SetDateMessage, may be null for very old routers */
     void dateUpdated(String routerVersion) {
+        _routerVersion = routerVersion;
         boolean isrc = _context.isRouterContext();
         _routerSupportsFastReceive = isrc ||
                                      (routerVersion != null && routerVersion.length() > 0 &&
@@ -1881,6 +1883,18 @@ public abstract class I2PSessionImpl implements I2PSession, I2CPMessageReader.I2
         sendMessage_unchecked(new BlindingInfoMessage(bd, id));
     }
 
+    /**
+     *  Always valid in RouterContext. Returns null if not yet connected in I2PAppContext.
+     *
+     *  @return null if unknown
+     *  @since 0.9.46
+     */
+    public String getRouterVersion() {
+        if (_context.isRouterContext())
+            return CoreVersion.VERSION;
+        return _routerVersion;
+    }
+
     protected void updateActivity() {
         _lastActivity = _context.clock().now();
         if (_isReduced) {