Small VPN logging improvements

Author: pimterry

app/src/main/java/tech/httptoolkit/android/vpn/Session.java

@@ -408,7 +408,11 @@ public String getSessionKey() {
 	}
 
 	public static String getSessionKey(int destIp, int destPort, int sourceIp, int sourcePort) {
-		return PacketUtil.intToIPAddress(sourceIp) + ":" + sourcePort + "-" +
+		return PacketUtil.intToIPAddress(sourceIp) + ":" + sourcePort + "->" +
 				PacketUtil.intToIPAddress(destIp) + ":" + destPort;
 	}
+
+	public String toString() {
+		return "Session (" + this.getSessionKey() + ")";
+	}
 }

app/src/main/java/tech/httptoolkit/android/vpn/SessionHandler.java

@@ -136,14 +136,13 @@ private void handleTCPPacket(ByteBuffer clientPacketData, IPv4Header ipHeader) t
 			Session session = manager.getSessionByKey(key);
 
 			if(session == null) {
+				Log.w(TAG, "Ack for unknown session: " + key);
 				if (tcpheader.isFIN()) {
 					sendLastAck(ipHeader, tcpheader);
 				} else if (!tcpheader.isRST()) {
 					sendRstPacket(ipHeader, tcpheader, dataLength);
 				}
-				else {
-					Log.e(TAG,"**** ==> Session not found: " + key);
-				}
+
 				return;
 			}
 
@@ -305,7 +304,7 @@ private void sendAck(IPv4Header ipheader, TCPHeader tcpheader, int acceptedDataL
 
 	private void sendAckForDisorder(IPv4Header ipHeader, TCPHeader tcpheader, int acceptedDataLength) {
 		long ackNumber = tcpheader.getSequenceNumber() + acceptedDataLength;
-		Log.d(TAG,"sent ack, ack# " + tcpheader.getSequenceNumber() +
+		Log.d(TAG,"sent disorder ack, ack# " + tcpheader.getSequenceNumber() +
 				" + " + acceptedDataLength + " = " + ackNumber);
 		byte[] data = TCPPacketFactory.createResponseAckData(ipHeader, tcpheader, ackNumber);
 

app/src/main/java/tech/httptoolkit/android/vpn/network/ip/IPPacketFactory.java

@@ -98,7 +98,7 @@ public static IPv4Header createIPv4Header(@NonNull ByteBuffer stream) throws Pac
 		final byte versionAndHeaderLength = stream.get();
 		final byte ipVersion = (byte) (versionAndHeaderLength >> 4);
 		if (ipVersion != 0x04) {
-			throw new PacketHeaderException("Invalid IPv4 header. IP version should be 4.");
+			throw new PacketHeaderException("Invalid IPv4 header. IP version should be 4 but was " + ipVersion);
 		}
 
 		final byte internetHeaderLength = (byte) (versionAndHeaderLength & 0x0F);

app/src/main/java/tech/httptoolkit/android/vpn/transport/icmp/ICMPPacketFactory.java

@@ -30,7 +30,7 @@ public static ICMPPacket parseICMPPacket(@NonNull ByteBuffer stream) throws Pack
         if (type == 8) {
             return new ICMPPacket(type, code, checksum, identifier, sequenceNumber, data);
         } else {
-            throw new PacketHeaderException("For ICMP, only echo requests are supported");
+            throw new PacketHeaderException("Unknown ICMP type (" + type + "). Only echo requests are supported");
         }
     }