I2CP: Add option for forcing gzip on/off per-message

Use option in streaming SYN and CLOSE packets

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

@@ -147,6 +147,10 @@ class PacketQueue implements SendMessageStatusListener, Closeable {
                 }
                 options.setTagsToSend(sendTags);
                 options.setTagThreshold(tagThresh);
+                // CLOSE, RESET, and PING packets unlikely to have a large payload
+                // and most of the rest of the packet is
+                // uncompressible: stream ids, signature
+                options.setGzip(packet.getPayloadSize() > 50);
             } else if (packet.isFlagSet(FLAGS_INITIAL_TAGS)) {
                 if (con != null) {
                     if (con.isInbound())
@@ -167,6 +171,11 @@ class PacketQueue implements SendMessageStatusListener, Closeable {
                 }
                 options.setTagsToSend(sendTags);
                 options.setTagThreshold(tagThresh);
+                // SYN packets are likely to have compressible payload, even if
+                // conn gzip option is false (e.g. snark bitfield, HTTP headers).
+                // If they don't have a large payload, most of the rest of the packet
+                // is uncompressible: stream ids, destination and signature
+                options.setGzip(packet.getPayloadSize() > 50);
             } else {
                 if (con != null) {
                     if (con.isInbound() && con.getLifetime() < 2*60*1000)

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

@@ -12,10 +12,15 @@ import net.i2p.data.DateAndFlags;
  *  Static methods are for OutboundClientMessageOneShotJob to decode the
  *  flags field on the router side.
  *
+ *  GzipOption flags are as of 0.9.36, are client-side only, and are
+ *  not included in the flags field or sent to the router.
+ *
  *  @since 0.9.2
  */
 public class SendMessageOptions extends DateAndFlags {
 
+    private GzipOption _gzip = GzipOption.DEFAULT;
+
     /** all subject to change */
 
     /**
@@ -205,4 +210,33 @@ public class SendMessageOptions extends DateAndFlags {
             return Reliability.DEFAULT;
         }
     }
+
+    /**
+     *  Overrides i2cp.gzip session option and size threshold
+     *  for this message only.
+     *
+     *  @since 0.9.36
+     */
+    public enum GzipOption { DEFAULT, GZIP_OFF, GZIP_ON }
+
+    /**
+     *  Overrides i2cp.gzip session option and size threshold
+     *  for this message only.
+     *
+     *  @return non-null, DEFAULT unless setGzip() was called
+     *  @since 0.9.36
+     */
+    public GzipOption getGzip() {
+        return _gzip;
+    }
+
+    /**
+     *  Overrides i2cp.gzip session option and size threshold
+     *  for this message only.
+     *
+     *  @since 0.9.36
+     */
+    public void setGzip(boolean yes) {
+        _gzip = yes? GzipOption.GZIP_ON : GzipOption.GZIP_OFF;
+    }
 }

core/java/src/net/i2p/client/impl/I2PSessionMuxedImpl.java

@@ -217,7 +217,7 @@ class I2PSessionMuxedImpl extends I2PSessionImpl2 {
                                SessionKey keyUsed, Set<SessionTag> tagsSent, long expires,
                                int proto, int fromPort, int toPort, int flags)
                    throws I2PSessionException {
-        payload = prepPayload(payload, offset, size, proto, fromPort, toPort);
+        payload = prepPayload(payload, offset, size, proto, fromPort, toPort, SendMessageOptions.GzipOption.DEFAULT);
         if (_noEffort)
             return sendNoEffort(dest, payload, expires, flags);
         else
@@ -242,7 +242,7 @@ class I2PSessionMuxedImpl extends I2PSessionImpl2 {
     @Override
     public boolean sendMessage(Destination dest, byte[] payload, int offset, int size,
                                int proto, int fromPort, int toPort, SendMessageOptions options) throws I2PSessionException {
-        payload = prepPayload(payload, offset, size, proto, fromPort, toPort);
+        payload = prepPayload(payload, offset, size, proto, fromPort, toPort, options.getGzip());
         //if (_noEffort) {
             sendNoEffort(dest, payload, options);
             return true;
@@ -266,7 +266,7 @@ class I2PSessionMuxedImpl extends I2PSessionImpl2 {
     public long sendMessage(Destination dest, byte[] payload, int offset, int size,
                             int proto, int fromPort, int toPort,
                             SendMessageOptions options, SendMessageStatusListener listener) throws I2PSessionException {
-        payload = prepPayload(payload, offset, size, proto, fromPort, toPort);
+        payload = prepPayload(payload, offset, size, proto, fromPort, toPort, options.getGzip());
         long nonce = _sendMessageNonce.incrementAndGet();
         long expires = Math.max(_context.clock().now() + 60*1000L, options.getTime());
         MessageState state = new MessageState(_context, nonce, this, expires, listener);
@@ -279,11 +279,19 @@ class I2PSessionMuxedImpl extends I2PSessionImpl2 {
      * @return gzip compressed payload, ready to send
      * @since 0.9.14
      */
-    private byte[] prepPayload(byte[] payload, int offset, int size, int proto, int fromPort, int toPort) throws I2PSessionException {
+    private byte[] prepPayload(byte[] payload, int offset, int size, int proto,
+                               int fromPort, int toPort,
+                               SendMessageOptions.GzipOption gzo) throws I2PSessionException {
         verifyOpen();
         updateActivity();
 
-        if (shouldCompress(size))
+        boolean docompress;
+        if (gzo == SendMessageOptions.GzipOption.DEFAULT)
+            docompress = shouldCompress(size);
+        else
+            docompress = gzo == SendMessageOptions.GzipOption.GZIP_ON;
+
+        if (docompress)
             payload = DataHelper.compress(payload, offset, size);
         else
             payload = DataHelper.compress(payload, offset, size, DataHelper.NO_COMPRESSION);