SOCKS: Fix NPE on lookup failure in SOCKS 4a

Remove duplicate lookups in SOCKS 5
Log tweaks
Streaming, i2ptunnel: Catch null destination in connect() calls
Synchronize Connection.setRemotePeer(); remove _remotePeerSet field

apps/streaming/java/src/net/i2p/client/streaming/impl/Connection.java

@@ -825,16 +825,23 @@ class Connection {
     public void schedule(SimpleTimer.TimedEvent event, long msToWait) {
         _timer.addEvent(event, msToWait);
     }
-    
-    private boolean _remotePeerSet = false;
+
     /** who are we talking with
-     * @return peer Destination
+     * @return peer Destination or null if unset
+     */
+    public synchronized Destination getRemotePeer() { return _remotePeer; }
+
+    /**
+     *  @param peer non-null
      */
-    public Destination getRemotePeer() { return _remotePeer; }
     public void setRemotePeer(Destination peer) { 
-        if (_remotePeerSet) throw new RuntimeException("Remote peer already set [" + _remotePeer + ", " + peer + "]");
-        _remotePeerSet = true;
-        _remotePeer = peer; 
+        if (peer == null)
+            throw new NullPointerException();
+        synchronized(this) {
+            if (_remotePeer != null)
+                throw new RuntimeException("Remote peer already set [" + _remotePeer + ", " + peer + "]");
+            _remotePeer = peer; 
+        }
         // now that we know who the other end is, get the rtt etc. from the cache
         _connectionManager.updateOptsFromShare(this);
     }
@@ -1220,7 +1227,7 @@ class Connection {
             buf.append(" from ");
         else
             buf.append(" to ");
-        if (_remotePeerSet)
+        if (_remotePeer != null)
             buf.append(_remotePeer.calculateHash().toBase64().substring(0,4));
         else
             buf.append("unknown");

apps/streaming/java/src/net/i2p/client/streaming/impl/ConnectionManager.java

@@ -395,12 +395,14 @@ class ConnectionManager {
      * Build a new connection to the given peer.  This blocks if there is no
      * connection delay, otherwise it returns immediately.
      *
-     * @param peer Destination to contact
+     * @param peer Destination to contact, non-null
      * @param opts Connection's options
      * @param session generally the session from the constructor, but could be a subsession
      * @return new connection, or null if we have exceeded our limit
      */
     public Connection connect(Destination peer, ConnectionOptions opts, I2PSession session) {
+        if (peer == null)
+            throw new NullPointerException();
         Connection con = null;
         long expiration = _context.clock().now();
         long tmout = opts.getConnectTimeout();

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

@@ -479,7 +479,13 @@ class ConnectionPacketHandler {
             if (con.getSendStreamId() <= 0) {
                 if (packet.isFlagSet(Packet.FLAG_SYNCHRONIZE)) {
                     con.setSendStreamId(packet.getReceiveStreamId());
-                    con.setRemotePeer(packet.getOptionalFrom());
+                    Destination dest = packet.getOptionalFrom();
+                    if (dest == null) {
+                        if (_log.shouldWarn())
+                            _log.warn("SYN Packet without FROM");
+                        return false;
+                    }
+                    con.setRemotePeer(dest);
                     return true;
                 } else {
                     // neither RST nor SYN and we dont have the stream id yet?

apps/streaming/java/src/net/i2p/client/streaming/impl/I2PSocketManagerFull.java

@@ -524,6 +524,8 @@ public class I2PSocketManagerFull implements I2PSocketManager {
      */
     public I2PSocket connect(Destination peer, I2PSocketOptions options) 
                              throws I2PException, NoRouteToHostException {
+        if (peer == null)
+            throw new NullPointerException();
         if (options == null)
             options = _defaultOptions;
         ConnectionOptions opts = null;