UDGuard

UDGuard is a base implementation of a zero-dependency DNS Proxy that enables authentication and packet processing. The data can be altered by adding custom code in the DNSLookupHandler function.

Function to Modify

To customize the DNS Proxy behavior, modify the following function in cmd/udguard/main.go:

func DNSLookupHandler(msg []byte, addr *net.UDPAddr, s_conn *net.UDPConn) {
    c_conn, err := internal.StartClient("1.1.1.1", "53")
    if err != nil {
        logger.Fatal(err)
        panic(err)
    }
    defer c_conn.Close()

    log.Println("Sending request to DNS server")
    _, err = c_conn.Write(msg)

    var buf [512]byte
    _, _, err = c_conn.ReadFromUDP(buf[0:])
    if err != nil {
        logger.Fatal(err)
    }
    log.Println("Received response from DNS server")
    log.Println(buf)

    log.Println("Waiting for response from DNS server")

    // ADD CODE HERE <------------

    log.Println("Sending response to client")
    _, err = s_conn.WriteToUDP(buf[:], addr)
    if err != nil {
        logger.Fatal(err)
    }
}

Main Programs

There are two main programs in this repository located under the cmd/ folder:

• udguard: The main DNS Proxy server.
• stresser: A tool for stress testing the proxy.

Building and Compiling

To build and compile the programs, follow these steps:

1. Clone the repository:

   git clone https://github.com/joaoofreitas/udguard.git
   cd udguard

2. Build the main udguard program:

   cd cmd/udguard
   go build -o udguard

3. Build the stresser program:

   cd cmd/stresser
   go build -o stresser

Testing

To test the udguard DNS Proxy, you can use the stresser tool:

1. Start the udguard server:

   ./udguard

2. In another terminal, run the stresser tool:

   ./stresser

The stresser tool will send multiple DNS requests to the udguard server to test its performance and stability.

Responsibility

This code is provided as a base for implementing a DNS Proxy and is intended for educational and testing purposes only. It is not written with bad intentions, and I am not responsible for any misuse of this code, including its use as a basis for malware.