kingkeule / vpnubt

This tool sniffs local UDP broadcast pakets and forwards them as unicast to a specific IP adress.

VPNubt (VPN-udp-broadcast-tunneler)

Our tool "copies" udp broadcasts on the selected port to udp unicasts which are sent to the specific IP address to bypass the VPN router barrier.

Background

We love to play old school games like Warcraft 3 with friends. Since we can't do a LAN session like in our youth, we play over the internet via VPN without using Battle.Net. The problem with e.g. Warctaft 3 is that the server could not be found even if we are connected via VPN.

(VPN means here classic OSI layer 3 VPNs and not a OSI layer 2 bridge VPN.)

What is the reason for that?

The game server sends an udp broadcast to notify all player in the LAN. When you play over internet via VPN there is normaly a consumer router which do not relay this braodcast otherwise the network/internet would be flooded.

(Only professional routers could do this with a directed broadcast)

How we solved the problem

We have programmed a tool that listen on the selected network interface for udp broadcasts. If an udp broadcast is detected, its payload is copied into an udp unicast packet and then sent to the VPN receiver, because a unicast is not filtered by the router.

Are there other solutions for this problem?

All of the following tools solve the problem, but in a different way. They do not "convert" the broadcast and instead send an fixed predefined communication specifically for Warcraft 3.

• LanCraft (updated in 2008)
• WC3Proxy (Sourcecode @ GitHub, updated in 2015)
• YAWLE (updated in 2008)

Why a new tool?

Some of the programs mentioned above only work specifically for one game. Our tool on the other hand can be used universally and is not limited to Warcraft 3, for example. In addition, we wanted to realize the implementation in a current programming language (GO).

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Reverse enigneering (of Warcraft 3)

If you want to know how we reengineered it, read on here.

1. Identify the communication port of the game (on Windows 10)

   • Start the game (Warcraft 3) and entert he multiplayer lobby
   • Switch to windows and open the command line and type: tasklist | findstr war3.exe
   • Note the displayed process id of Warcraft 3
   • Type in command line: netstat -ano | findstr <Warcraft 3 process id>
   • So finally we find out that Warcraft is listen only for UDP communication on port 6112

2. Understand the Warcraft 3 communication on UDP port 6112

   • Install and start Wireshark

   • Set the Wireshark displayfilter to: udp.port == 6112

   • You can divide it in 3 Parts:

     1. "Hello" information"
        When you enter the network lobby, Warcraft will only send a notifcation boradcast once:

        • Source: local IP of client
        • Destination: 255.255.255.255
        • Port: UDP 6112
        • Data: 0xf72f1000505833571b00000000000000

        (the data is always the same for each warcraft pc)

     2. "Server waiting"
        When you open a LAN game, the server sends every 5 seconds (may depend on the patch version) a notifcation boradcast:

        • Source: local IP of server

        • Destination: 255.255.255.255

        • Port: UDP 6112

        • Data: 0xf7321000010000000100000003000000
          The data is defined as:

          # (byte)	Data	dynamic	Description
          01	f7	no	W3 identification (fix)
          02	32	no	W3 identification (fix)
          03	10	no	W3 identification (fix)
          04	00	no	Reserved
          05	01	yes	Number of opened LAN games since Warcraft started. (here 1)
          06	00	no	Reserved
          07	00	no	Reserved
          08	00	no	Reserved
          09	01	no	Total number of (joined) players in the game. (here only the server himself)
          10	00	no	Reserved
          11	00	no	Reserved
          12	00	no	Reserved
          13	03	no	Number of possible players on the map. (here 3)
          14	00	no	Reserved
          15	00	no	Reserved
          16	00	no	Reserved

     3. "Abort"
        When you abort the open game:

        • Source: local IP of client
        • Destination: 255.255.255.255
        • Port: UDP 6112
        • Data: 0xf733080001000000

3. Proof of Concept
   Try to inform the game server by sending an unicast instead of broadcast by an external tool. For this PoC we used the software nping

   • Start on the remote computer (server) Warcraft 3.
   • Call nping (C:\Program Files (x86)\Nmap\nping) from command line on the client:
     • nping -c 1 --udp --source-port 6112 --dest-port 6112 --source-ip 192.168.1.2 --dest-ip 192.168.1.10 --data f72f1000505833571b00000000000000

   We got the answer from the server with the information about the open LAN game. So we could join the game.
   The PoC works! 👍 😄

vpnubt's Issues

Cannot See LAN server unless both are running it.

Greetings.

I tested the program today and I discovered that, after port forwarding everything, if my friend is running the program trying to connect to me he will not see the game. The log shows the packets were sent and received though. The only way for us to play was with both of us to enter each other's IP, use the same port, and run the program.

While it working was great... this means that it only supports two players at a maximum. Is there anything we are doing wrong on our end? Would love to use this program if it supported more one active connection at a time.

Reduce/move README Content

The current toplevel README is way to large

It should just show the mandatory information and explain the usage of the tool, maybe by screenshot

The rest could be moved to another README file in doc/ subfolder or similar

Define and implement Interface between UI and Service

Implement Tests

Tool does not launch due to missing png's for UI

2020/11/12 18:24:18 Could not find the ressource
2020/11/12 18:24:18 open img\icons8-tunnel-24.png: Das System kann den angegebenen Pfad nicht finden.

This file should be part of release package.

Fix for now is to download the png and place it manually in a new folder "img" next to the exe

Missleading UI Label

"Tunneling Service" should be renamed to "Broadcast Service" or similar

It's not (yet) a VPN Tunnel Client, although Plans exist to integrate Wireguard natively

Migrate latest Code from Cmd Version here

32bit-Version to run on Linux/Wine

I wanted to try VPNubt for Wine on Linux to run Windows games.

For example, Lancraft worked fine so far, but i want to have a universal tool, so other games might work with that as well.

Unfortunately lots of games need to run in win32 WINEARCH, so your 64bit compilation in your releases is not starting at all.

I would like to have a 32bit-Version to run on 32bit systems.

So could you provide a 32bit release as well, please?

check and rebase git history

check for binaries e.g. debug_bin

Implement multithreading and stop routine for capture and forwarding

Ich habe es mit chanels versucht. hat auch erstmal ganz gut geklappt aber irgendwie dann doch nicht so richtig.
hauptproblem ist sehr wahrscheinlich der pacp handle und das "defer handle.Close()".

Logviewer decision

I created a new branch "logviewer" for the new feature log view window.
2 options:
a) use the windows console
b) create a new fyne window

Please check both options and let me know which option you prefer!

reorganise github folder

new folders are required (e.g. src, build, ... ) for better structure

add branch structure for upcoming tasks

develop, release, ...

Internet Usage Clarification

Greetings!

I wanted to verify and ask a few questions about this project.

1. Pure Internet Usage
   Could this program be used purely over the Internet without the use of a proper VPN connecting the clients together? (Assuming ports were forwarded.)

1a) Limited to 1 on 1? [EDITED]
If the answer above is yes then would it be limited to one-on-one connections? As currently, if my understanding is correct, you can only forward the packet to one ip address right?

[EDIT: After looking over the program I believe the intent is that anyone can attempt a connection with a host who has open ports. The host themselves does not run the program. So the question is really "Many-To-One" setup.]

1b) Dynamic Hub Creation [EDITED]
If the answer to 1 & 1a is yes then could there be an addition for this project be a "dynamic hub?"

This would allow for one host, if they have the 'dynamic hub' setting enabled, log the ip address of whomever sent a incoming unicast packet to them on the specified port and proceed to then forward any and all future unicast packets it receives to all the addresses it has logged.

[EDIT: To better clarify this idea I posted a revised description below:

There would be an option to run this program in HUB mode. What HUB mode does is log the IP & Port of whoever tunnels to it. Afterwards any unicasts sent by clients to the HUB will be relayed, via multicast, to everyone else who is connected on that port.]