eqMac/native/app/Source/Helpers/Networking.swift

//
//  Networking.swift
//  eqMac
//
//  Created by Roman Kisil on 08/07/2018.
//  Copyright © 2018 Roman Kisil. All rights reserved.
//

import Foundation
import Reachability

class Networking {
  //  static func isReachable (_ host: String, _ callback: @escaping (Bool) -> Void) {
  //    if let ping = try? SwiftyPing(
  //      host: host,
  //      configuration: PingConfiguration(interval: 0.1, with: 5),
  //      queue: DispatchQueue.global()
  //      ) {
  //      ping.observer = { (response) in
  //        callback(response.error == nil)
  //        ping.stopPinging()
  //      }
  //      ping.startPinging()
  //    } else {
  //      callback(false)
  //    }
  //  }
  
  static func isReachable (_ host: String, _ callback: @escaping (Bool) -> Void) {
    let reachability = try! Reachability(hostname: host)
    
    reachability.whenReachable = { reachability in
      reachability.stopNotifier()
      callback(true)
    }
    reachability.whenUnreachable = { _ in
      reachability.stopNotifier()
      callback(false)
    }
    
    do {
      try reachability.startNotifier()
    } catch {
      callback(false)
    }
  }
  
  static func tcpPortIsAvailable(_ port: UInt) -> Bool {
    
    let socketFileDescriptor = socket(AF_INET, SOCK_STREAM, 0)
    if socketFileDescriptor == -1 {
      return false
    }
    
    var addr = sockaddr_in()
    let sizeOfSockkAddr = MemoryLayout<sockaddr_in>.size
    addr.sin_len = __uint8_t(sizeOfSockkAddr)
    addr.sin_family = sa_family_t(AF_INET)
    addr.sin_port = Int(OSHostByteOrder()) == OSLittleEndian ? _OSSwapInt16(__uint16_t(port)) : in_port_t(port)
    addr.sin_addr = in_addr(s_addr: inet_addr("0.0.0.0"))
    addr.sin_zero = (0, 0, 0, 0, 0, 0, 0, 0)
    var bind_addr = sockaddr()
    memcpy(&bind_addr, &addr, Int(sizeOfSockkAddr))
    
    if Darwin.bind(socketFileDescriptor, &bind_addr, socklen_t(sizeOfSockkAddr)) == -1 {
      release(socket: socketFileDescriptor)
      return false
    }
    if listen(socketFileDescriptor, SOMAXCONN ) == -1 {
      release(socket: socketFileDescriptor)
      return false
    }
    release(socket: socketFileDescriptor)
    return true
  }
  
  static func getAvailabilePort (_ start: UInt) -> UInt {
    var port = start
    while !tcpPortIsAvailable(port) {
      port += 1
    }
    return port
  }
  
  static func release(socket: Int32) {
    Darwin.shutdown(socket, SHUT_RDWR)
    close(socket)
  }
}