create a udp client on a specific port in swift

main.swift
import Foundation

func startUDPClient() {
    let port: UInt16 = 9999 // Select a port number
    
    var clientSocket: CFSocket? = nil
    clientSocket = CFSocketCreate(kCFAllocatorDefault, AF_INET, SOCK_DGRAM, IPPROTO_UDP, 0, nil, nil)
    
    // Bind the socket to a specific port
    var address = sockaddr_in()
    address.sin_len = UInt8(MemoryLayout<sockaddr_in>.size)
    address.sin_family = sa_family_t(AF_INET)
    address.sin_addr.s_addr = htonl(INADDR_ANY)
    address.sin_port = htons(port)
    
    let data = withUnsafePointer(to: &address) {
        return Data(bytes: $0, count: MemoryLayout<sockaddr_in>.size)
    }
    
    let result = CFSocketSetAddress(clientSocket, data as CFData)
    if result != CFSocketError.success {
        print("Error binding socket to port \(port)")
        return
    }
    
    // Start receiving data on the socket
    var buffer = [UInt8](repeating: 0, count: 1024)
    let addressSize = MemoryLayout<sockaddr_in>.size
    while true {
        let bytesRead = recvfrom(CFSocketGetNative(clientSocket), &buffer, buffer.count, 0, nil, nil)
        let senderAddressPtr = UnsafeRawPointer(buffer).assumingMemoryBound(to: sockaddr_in.self)
        let senderAddress = senderAddressPtr.pointee
        
        let senderIP = String(cString: inet_ntoa(senderAddress.sin_addr), encoding: .ascii)
        let senderPort = Int(senderAddress.sin_port).byteSwapped
        
        let message = String(bytes: buffer[0..<bytesRead], encoding: .utf8)!
        print("\(senderIP!):\(senderPort) says: \(message)")
    }
}
1568 chars
41 lines