How to Implement Network Port Access in OMNeT++
To implement the network port access in OMNeT++, we have to simulate a scenario where various applications and service interact with certain network ports for communication. It is especially helpful when studying situations like firewall rules, port scanning, or application-layer protocols (e.g., HTTP, FTP) that rely on specific ports for operation. In below, we offered the step-by-step process to implement it in OMNeT++:
Step-by-Step Implementation:
Step 1: Set Up the OMNeT++ Environment
Make sure that OMNeT++ and the essential libraries like INET are installed and configured properly. INET offers models for different network protocols, which can be extended or set up to mimic port-based communication.
Step 2: Define the Network Node with Port Access
Begin by generate a network node which can simulate service performing on certain ports, The node will use TCP or UDP to listen on specific ports and manage incoming connections.
Example Network Node Definition
module PortAccessNode
{
parameters:
@display(“i=block/server”); // Icon for better visualization
gates:
inout ethg; // Ethernet communication gate
submodules:
eth: <default(“EthernetInterface”)>; // Ethernet NIC for communication
tcpApp[2]: TcpBasicServerApp { // TCP applications listening on different ports
@display(“p=100,200”);
}
udpApp: UdpBasicApp { // UDP application listening on a port
@display(“p=100,300”);
}
connections:
ethg <–> eth.physIn;
}
Step 3: Implement TCP and UDP Applications
Execute TCP and UDP applications on the node that listen on specific ports and cope with incoming traffic.
Example TCP Application (TcpBasicServerApp)
class TcpBasicServerApp : public TcpServerHostApp
{
protected:
virtual void handleMessage(cMessage *msg) override;
private:
int port;
};
void TcpBasicServerApp::handleMessage(cMessage *msg)
{
if (msg->getKind() == TCP_I_PEER_CLOSED) {
// Handle connection close event
EV << “TCP connection closed on port ” << port << endl;
delete msg;
}
else {
// Handle incoming data
EV << “Received message on TCP port ” << port << “: ” << msg->getName() << endl;
send(msg, “socketOut”); // Echo the message back
}
}
Example UDP Application (UdpBasicApp)
class UdpBasicApp : public cSimpleModule
{
protected:
virtual void handleMessage(cMessage *msg) override;
private:
int port;
};
void UdpBasicApp::handleMessage(cMessage *msg)
{
// Handle incoming UDP packets
EV << “Received message on UDP port ” << port << “: ” << msg->getName() << endl;
delete msg; // Process and delete the message
}
Step 4: Define the Network Scenario with Port Access
Generate a network scenario where nodes communicate using specific ports. This can simulate a server-client model, where clients use services running on specific ports.
Example Network Scenario Definition
network PortAccessNetwork
{
parameters:
int numClients = default(2); // Number of clients in the network
submodules:
server: PortAccessNode {
@display(“p=300,300”);
}
clients[numClients]: PortAccessNode {
@display(“p=100,100”);
}
connections allowunconnected:
server.ethg <–> EthernetCable <–> clients[0].ethg;
server.ethg <–> EthernetCable <–> clients[1].ethg;
}
Step 5: Configure the Simulation Parameters
Define the simulation parameters in the .ini file, containing the ports on which services are running, and how the clients interact with these services.
Example Configuration in the .ini File
network = PortAccessNetwork
sim-time-limit = 300s
# Server configuration
*.server.tcpApp[0].localPort = 80 # HTTP-like service on port 80
*.server.tcpApp[1].localPort = 443 # HTTPS-like service on port 443
*.server.udpApp.localPort = 53 # DNS-like service on port 53
# Client configuration (TCP)
*.clients[0].tcpApp[0].connectPort = 80 # Connect to HTTP service
*.clients[1].tcpApp[0].connectPort = 443 # Connect to HTTPS service
# Client configuration (UDP)
*.clients[*].udpApp.destPort = 53 # Send DNS-like queries
*.clients[*].udpApp.messageLength = 128B
*.clients[*].udpApp.sendInterval = 5s
# Set up Ethernet communication parameters
*.server.eth.datarate = 100Mbps
*.clients[*].eth.datarate = 100Mbps
Step 6: Implement Traffic Generation (Clients)
Execute the logic for clients to send traffic to the server on specific ports. It can accomplished using applications like TcpBasicClientApp and UdpBasicApp.
Example TCP Client Logic
class TcpBasicClientApp : public TcpAppBase
{
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
private:
int port;
cMessage *timer; // Timer to trigger sending data
};
void TcpBasicClientApp::initialize()
{
port = par(“connectPort”);
timer = new cMessage(“sendTimer”);
scheduleAt(simTime() + par(“startTime”), timer);
}
void TcpBasicClientApp::handleMessage(cMessage *msg)
{
if (msg == timer)
{
EV << “Connecting to server on port ” << port << endl;
send(createDataPacket(“TCPClientMessage”, 100), “socketOut”); // Example message
scheduleAt(simTime() + par(“sendInterval”), timer);
}
else
{
// Handle incoming messages or connection events
EV << “Received response on TCP port ” << port << endl;
delete msg;
}
}
Step 7: Run the Simulation
Compile and run the simulation. During the simulation, clients will try to link to the server on specific ports and transmit data. The server will manage incoming connections and respond properly.
Step 8: Analyze the Results
Use OMNeT++’s analysis tools to assess the performance of the network. Focus on metrics like:
- Port Accessibility: Confirm if the services running on specific ports are accessible to the clients.
- Throughput and Latency: Evaluate how the port-based communication affects network performance.
- Error Handling: Assess how the network manages cases where clients try to access closed or blocked ports.
Step 9: Extend the Simulation (Optional)
You can extend the simulation by:
- Implementing a Firewall: Imitate a firewall that blocks or permits traffic as per the port numbers.
- Simulating Port Scanning: Implement a port scanning application to probe the server for open ports.
- Adding More Services: Include more services and clients to simulate a difficult network with several applications running on various ports.
- Testing with Different Protocols: Examine with multiple protocols like HTTP, FTP, DNS, and analyze how they interact with the network.
With the help of this demonstration, you can learn the concept and also be able to implement the Network Port Access using INET framework and OMNeT++. If you have any doubts about these steps, we will resolve it through another manual.
Implementation of Network Port Access is significantly enhanced by the expertise of the developers at omnet-manual.com, who provide tailored services to meet your specific needs. We are committed to guiding you through every phase of your project, offering comparative analysis results to ensure your success. Our team specializes in addressing various scenarios, including firewall rules, port scanning, and application-layer protocols such as HTTP and FTP, all tailored to the unique requirements of your project.