Swift多播多个连接到相同的端口

huangapple
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英文:

Swift multicast multiple connection to the same port

问题

我有两个安装在同一设备上的应用程序，它们尝试连接到一个多播组，第一个应用程序成功连接，而第二个应用程序出现错误：
监听器失败，错误为
组进入状态失败（POSIXErrorCode(rawValue: 48): 地址已被使用）

我以为allowLocalEndpointReuse允许多个客户端连接到相同的端口，但它不起作用。

  1. let port = NWEndpoint.Port(portUdp) ?? NWEndpoint.Port(5353)
  2. let host = NWEndpoint.Host(urlUdp)
  3. guard let multicast = try? NWMulticastGroup(for:
  4.  [ .hostPort(host: host, port: port) ])
  5.  else {
  6.      stateMultiCast = "带有URL和端口的错误"
  7.  return
  8.  }
  10. let parameters = NWParameters.udp
  11. parameters.allowLocalEndpointReuse = true
  12. parameters.allowLocalEndpointReuse
  13. let group = NWConnectionGroup(with: multicast, using: parameters)
  15. group.setReceiveHandler(maximumMessageSize: 16384, rejectOversizedMessages: true) 
  16.   { (message, content, isComplete) in
  17.         // ....
  18.     }
  20. group.stateUpdateHandler = { (newState) in
  21.     print("组进入状态 \(String(describing: newState))")
  22. }
  23. group.start(queue: .main)

如何让多个应用程序使用相同的端口，以便这些应用程序可以接收UDP服务器发送的所有相同消息？

感谢您的帮助。

英文:

I have two applications installed on the same device and they trying to connect to a multicast group the first application has a succeed connection the second one has error :
listener failed with error
Group entered state failed(POSIXErrorCode(rawValue: 48): Address already in use)
I thought that allowLocalEndpointReuse allows several clients to connect to the same port

but it doesn't work.

  1.     let port = NWEndpoint.Port(portUdp) ?? NWEndpoint.Port(5353)
  2.     let host = NWEndpoint.Host(urlUdp)
  3.     guard let multicast = try? NWMulticastGroup(for:
  4.      [ .hostPort(host: host, port: port) ])
  5.      else {
  6.          stateMultiCast = "Error with url and port"
  7.      return
  8.      }
  9.     
  10.     let parameters = NWParameters.udp
  11.     parameters.allowLocalEndpointReuse = true
  12.     parameters.allowLocalEndpointReuse
  13.     let group = NWConnectionGroup(with: multicast, using: parameters)
  15.     
  16.     group.setReceiveHandler(maximumMessageSize: 16384, rejectOversizedMessages: true) 
  17.   { (message, content, isComplete) in
  18.         ....
  19.     }
  20.     
  21.     group.stateUpdateHandler = { (newState) in
  22.         print("Group entered state \(String(describing: newState))")
  23.     }
  24.     group.start(queue: .main)

How can i use the same port for several application so this application can receive all the same message sent by udp server ?

Thank you for your help

答案1

得分: -1

我找到了一个不同于苹果推荐的多播组的解决方案：

  1. func setupMulticastSocket(urlUdp: String, portUdp: String) -> Int32 {
  2.   
  3.     let multicastAddress = urlUdp
  4.     let multicastPort: UInt16 = UInt16(portUdp) ?? 0
  5.     // 创建一个UDP套接字
  6.     let socketFileDescriptor = socket(AF_INET, SOCK_DGRAM, 0)
  7.     guard socketFileDescriptor != -1 else {
  8.         print("创建套接字失败")
  9.         exit(1)
  10.     }
  11.     // 启用多播回环
  12.     var loop: UInt32 = 1
  13.     guard setsockopt(socketFileDescriptor, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, socklen_t(MemoryLayout<UInt32>.size)) != -1 else {
  14.         print("启用多播回环失败")
  15.         exit(1)
  16.     }
  17.     
  18.     var reuseFlag: Int32 = 1
  19.     let reuseOption = withUnsafePointer(to: &reuseFlag) { ptr in
  20.         return UnsafeRawPointer(ptr).assumingMemoryBound(to: Int32.self)
  21.     }
  22.     
  23.     if setsockopt(socketFileDescriptor, SOL_SOCKET, SO_REUSEPORT, reuseOption, socklen_t(MemoryLayout<Int32>.size)) == -1 {
  24.         print("设置SO_REUSEPORT出错: \(String(describing: strerror(errno)))")
  25.         return -1
  26.     }
  27.     
  28.     if setsockopt(socketFileDescriptor, SOL_SOCKET, SO_REUSEADDR, reuseOption, socklen_t(MemoryLayout<Int32>.size)) == -1 {
  29.         print("设置SO_REUSEADDR出错: \(String(describing: strerror(errno)))")
  30.         return -1
  31.     }
  33.     // 将套接字绑定到特定的地址和端口
  34.     var socketAddress = sockaddr_in()
  35.     socketAddress.sin_len = __uint8_t(MemoryLayout<sockaddr_in>.size)
  36.     socketAddress.sin_family = sa_family_t(AF_INET)
  37.     socketAddress.sin_port = multicastPort.bigEndian
  38.     socketAddress.sin_addr.s_addr = CFSwapInt32HostToBig(INADDR_ANY)
  40.     withUnsafePointer(to: &socketAddress) { pointer in
  41.         let bindResult = pointer.withMemoryRebound(to: sockaddr.self, capacity: 1) { addrPointer in
  42.             bind(socketFileDescriptor, addrPointer, socklen_t(MemoryLayout<sockaddr_in>.size))
  43.         }
  44.         guard bindResult != -1 else {
  45.             print("绑定套接字失败")
  46.             exit(1)
  47.         }
  48.     }
  50.     // 加入多播组
  51.     var multicastRequest = ip_mreq()
  52.     multicastRequest.imr_multiaddr.s_addr = inet_addr(multicastAddress)
  53.     multicastRequest.imr_interface.s_addr = CFSwapInt32HostToBig(INADDR_ANY)
  55.     guard setsockopt(socketFileDescriptor, IPPROTO_IP, IP_ADD_MEMBERSHIP, &multicastRequest, socklen_t(MemoryLayout<ip_mreq>.size)) != -1 else {
  56.         print("加入多播组失败")
  57.         exit(1)
  58.     }
  60.     return socketFileDescriptor
  61. }
  63. // 调用函数如下：
  65. let socketFD = setupMulticastSocket(urlUdp: urlUdp, portUdp: portUdp)
  66. if socketFD != -1 {
  67.     print("多播套接字设置成功。")
  68. } else {
  69.     print("设置多播套接字失败。")
  70. }
  71. let bufferSize = 1024
  72. var buffer = [UInt8](repeating: 0, count: bufferSize)
  73. // 读取接收到的消息
  74. while true {
  75.     let bytesRead = recv(socketFD, &buffer, buffer.count, 0)
  76.     if bytesRead > 0 {
  77.         let messageData = Data(bytes: buffer, count: bytesRead)
  78.         let hexString = messageData.reduce("") { $0 + String(format: "%02x", $1) }
  79.         let decodedData = Data(hexString: hexString)!
  80.         if let decodedData = Data(hexString: hexString){
  81.             newDataRsaReceived(decodedData ?? Data())
  82.         }
  83.     }
  84. }

使用这个解决方案，多个客户端（应用程序）可以连接到相同的端口。

英文:

I found a solution different of multicast group that apple recommand :

func setupMulticastSocket(urlUdp : String, portUdp : String) -> Int32 {

  1.     let multicastAddress = urlUdp
  2. let multicastPort: UInt16 = UInt16(portUdp) ?? 0
  3. // Create a UDP socket
  4. let socketFileDescriptor = socket(AF_INET, SOCK_DGRAM, 0)
  5. guard socketFileDescriptor != -1 else {
  6. print(&quot;Failed to create socket&quot;)
  7. exit(1)
  8. }
  9. // Enable multicast loopback
  10. var loop: UInt32 = 1
  11. guard setsockopt(socketFileDescriptor, IPPROTO_IP, IP_MULTICAST_LOOP, &amp;loop, socklen_t(MemoryLayout&lt;UInt32&gt;.size)) != -1 else {
  12. print(&quot;Failed to enable multicast loopback&quot;)
  13. exit(1)
  14. }
  15. var reuseFlag: Int32 = 1
  16. let reuseOption = withUnsafePointer(to: &amp;reuseFlag) { ptr in
  17. return UnsafeRawPointer(ptr).assumingMemoryBound(to: Int32.self)
  18. }
  19. if setsockopt(socketFileDescriptor, SOL_SOCKET, SO_REUSEPORT, reuseOption, socklen_t(MemoryLayout&lt;Int32&gt;.size)) == -1 {
  20. print(&quot;Error setting SO_REUSEPORT: \(String(describing: strerror(errno)))&quot;)
  21. return -1
  22. }
  23. if setsockopt(socketFileDescriptor, SOL_SOCKET, SO_REUSEADDR, reuseOption, socklen_t(MemoryLayout&lt;Int32&gt;.size)) == -1 {
  24. print(&quot;Error setting SO_REUSEADDR: \(String(describing: strerror(errno)))&quot;)
  25. return -1
  26. }
  27. // Bind the socket to a specific address and port
  28. var socketAddress = sockaddr_in()
  29. socketAddress.sin_len = __uint8_t(MemoryLayout&lt;sockaddr_in&gt;.size)
  30. socketAddress.sin_family = sa_family_t(AF_INET)
  31. socketAddress.sin_port = multicastPort.bigEndian
  32. socketAddress.sin_addr.s_addr = CFSwapInt32HostToBig(INADDR_ANY)
  33. withUnsafePointer(to: &amp;socketAddress) { pointer in
  34. let bindResult = pointer.withMemoryRebound(to: sockaddr.self, capacity: 1) { addrPointer in
  35. bind(socketFileDescriptor, addrPointer, socklen_t(MemoryLayout&lt;sockaddr_in&gt;.size))
  36. }
  37. guard bindResult != -1 else {
  38. print(&quot;Failed to bind socket&quot;)
  39. exit(1)
  40. }
  41. }
  42. // Join the multicast group
  43. var multicastRequest = ip_mreq()
  44. multicastRequest.imr_multiaddr.s_addr = inet_addr(multicastAddress)
  45. multicastRequest.imr_interface.s_addr = CFSwapInt32HostToBig(INADDR_ANY)
  46. guard setsockopt(socketFileDescriptor, IPPROTO_IP, IP_ADD_MEMBERSHIP, &amp;multicastRequest, socklen_t(MemoryLayout&lt;ip_mreq&gt;.size)) != -1 else {
  47. print(&quot;Failed to join multicast group&quot;)
  48. exit(1)
  49. }
  50. return socketFileDescriptor
  51. }

I call the function like that :

  1.            let socketFD = setupMulticastSocket(urlUdp: urlUdp, portUdp: portUdp)
  2. if socketFD != -1 {
  3. print(&quot;Multicast socket set up successfully.&quot;)
  4. } else {
  5. print(&quot;Failed to set up multicast socket.&quot;)
  6. }
  7. let bufferSize = 1024
  8. var buffer = [UInt8](repeating: 0, count: bufferSize)
  9. // Reading message received
  10. while true {
  11. let bytesRead = recv(socketFD, &amp;buffer, buffer.count, 0)
  12. if bytesRead &gt; 0 {
  13. let messageData = Data(bytes: buffer, count: bytesRead)
  14. let hexString = messageData.reduce(&quot;&quot;) { $0 + String(format: &quot;%02x&quot;, $1) }
  15. let decodedData = Data(hexString: hexString)!
  16. if let decodedData = Data(hexString: hexString){
  17. newDataRsaReceived(decodedData ?? Data())
  18. }
  19. }
  20. }

With this solution multiple client (application) can connect to the same port

huangapple
  • 本文由 发表于 2023年6月12日 21:59:04
  • 转载请务必保留本文链接：https://go.coder-hub.com/76457403.html
  • multicast
  • sockets
  • swift
  • udp
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