# NAT Traversal
P2PRC currently supports TURN for NAT traversal. 

## TURN 
The current TURN implementation used is FRP. The TURN server is also required when 
a P2PRC node is acting as a Server. The TURN server is determined based on the Node 
with the least amount of latency based on the Nodes available on the IPTable. 
Once a TURN server is determined there are 2 actions performed. The first one is 
```/FRPPort``` to the TURN server to receive a port which is used to generate the external 
port from the TURN server. The flow below describes the workflow.

### Client mode
- Call ```/FRPPort```
```
http://<turn server ip>:<server port no>/FRPport
```
- Call the TURN server in the following manner. The following is a sample code snippet below. 
```go
import (
    "github.com/Akilan1999/p2p-rendering-computation/p2p/frp"
)

func main() {
  serverPort, err := frp.GetFRPServerPort("http://" + <lowestLatencyIpAddress.Ipv4> + ":" + lowestLatencyIpAddress.ServerPort)
   if err != nil {
    return nil, err
   }
   // Create 1 second delay to allow FRP server to start
   time.Sleep(1 * time.Second)
   // Starts FRP as a client with
   proxyPort, err := frp.StartFRPClientForServer(<lowestLatencyIpAddress.Ipv4>, serverPort, <the port you want to expose externally>)
   if err != nil {
     return nil, err
   }
}
```