我試圖創建一個iOS客戶端,通過設備的蜂窩通信將數據發送到UDP套接字上的服務器。將UDP套接字綁定到蜂窩IP
繼Does IOS support simultaneous wifi and 3g/4g connections? 連結iOS Multipath BSD Sockets Test,我試圖實現在夫特3中的溶液,即枚舉網絡接口設備中,識別蜂窩接口(如在Swift - Get device's IP Address建議的),創建UDP套接字並將其綁定到sockaddr從界面中檢索。
在Swift中實現套接字編程是通過以下示例從Socket Programming in Swift: Part 1 - getaddrinfo和以下帖子完成的。
不幸的是,我收到操作試圖發送套接字上的數據時,不允許,所以不是我試圖創建套接字,並從綁定到數據的getaddrinfo稱爲指定端口(5555)上。
這也沒有辦法。 有趣的是,在試圖瞭解什麼是錯誤的時候,我爲這兩種方法創建了一個測試應用程序,並且當連續1000次創建 - >綁定 - >發送 - >關閉測試時,大約有3-5次嘗試實際上是確實是在任一方法上發送沒有錯誤的數據。
不用說這是在實際的iPhone上測試的。
相當不知所措,我很感激任何關於此的建議。在靜態 「SocketManager」 類實現
碼(編輯:固定套接字地址分配大小)
// Return IP address String, port String & sockaddr of WWAN interface (pdp_ip0), or `nil`
public static func getInterface() -> (String?, String?, UnsafeMutablePointer<sockaddr>?) {
var host : String?
var service : String?
// Get list of all interfaces on the local machine:
var ifaddr : UnsafeMutablePointer<ifaddrs>?
var clt : UnsafeMutablePointer<sockaddr>?
guard getifaddrs(&ifaddr) == 0 else {
return (nil, nil, clt)
}
guard let firstAddr = ifaddr else {
return (nil, nil, clt)
}
// For each interface ...
for ifptr in sequence(first: firstAddr, next: { $0.pointee.ifa_next }) {
let interface = ifptr.pointee
let flags = Int32(ifptr.pointee.ifa_flags)
/// Check for running IPv4 interfaces. Skip the loopback interface.
if (flags & (IFF_UP|IFF_RUNNING|IFF_LOOPBACK)) == (IFF_UP|IFF_RUNNING) {
let addrFamily = interface.ifa_addr.pointee.sa_family
if addrFamily == UInt8(AF_INET) { //Interested in IPv4 for in particular case
// Check interface name:
let name = String(cString: interface.ifa_name)
print("interface name: \(name)")
if name.hasPrefix("pdp_ip") { //cellular interface
// Convert interface address to a human readable string:
let ifa_addr_Value = interface.ifa_addr.pointee
clt = UnsafeMutablePointer<sockaddr>.allocate(capacity: 1)
clt?.initialize(to: ifa_addr_Value, count: 1)
var hostnameBuffer = [CChar](repeating: 0, count: Int(NI_MAXHOST))
var serviceBuffer = [CChar](repeating: 0, count: Int(NI_MAXSERV))
getnameinfo(interface.ifa_addr, socklen_t(ifa_addr_Value.sa_len),
&hostnameBuffer, socklen_t(hostnameBuffer.count),
&serviceBuffer,
socklen_t(serviceBuffer.count),
NI_NUMERICHOST | NI_NUMERICSERV)
host = String(cString: hostnameBuffer)
if let host = host {
print("found host \(String(describing: host))")
}
service = String(cString: serviceBuffer)
if let service = service {
print("found service \(String(describing: service))")
}
break;
}
}
}
}
freeifaddrs(ifaddr)
return (host, service, clt)
}
public static func bindSocket(ip: String, port : String, clt : UnsafeMutablePointer<sockaddr>, useCltAddr : Bool = false) -> Int32 {
print("binding socket for IP: \(ip):\(port) withCltAddr=\(useCltAddr)")
var hints = addrinfo(ai_flags: 0,
ai_family: AF_INET,
ai_socktype: SOCK_DGRAM,
ai_protocol: IPPROTO_UDP,
ai_addrlen: 0,
ai_canonname: nil,
ai_addr: nil,
ai_next: nil)
var connectionInfo : UnsafeMutablePointer<addrinfo>? = nil
let status = getaddrinfo(
ip,
port,
&hints,
&connectionInfo)
if status != 0 {
var strError: String
if status == EAI_SYSTEM {
strError = String(validatingUTF8: strerror(errno)) ?? "Unknown error code"
} else {
strError = String(validatingUTF8: gai_strerror(status)) ?? "Unknown error code"
}
print(strError)
return -1
}
let socketDescriptor = useCltAddr ? socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP) : socket(connectionInfo!.pointee.ai_family, connectionInfo!.pointee.ai_socktype, connectionInfo!.pointee.ai_protocol)
if socketDescriptor == -1 {
let strError = String(utf8String: strerror(errno)) ?? "Unknown error code"
let message = "Socket creation error \(errno) (\(strError))"
freeaddrinfo(connectionInfo)
print(message)
return -1
}
let res = useCltAddr ? bind(socketDescriptor, clt, socklen_t(clt.pointee.sa_len)) : bind(socketDescriptor, connectionInfo?.pointee.ai_addr, socklen_t((connectionInfo?.pointee.ai_addrlen)!))
if res != 0 {
let strError = String(utf8String: strerror(errno)) ?? "Unknown error code"
let message = "Socket bind error \(errno) (\(strError))"
freeaddrinfo(connectionInfo)
close(socketDescriptor)
print(message)
return -1
}
freeaddrinfo(connectionInfo)
print("returned socket descriptor \(socketDescriptor)")
return socketDescriptor
}
//returns 0 for failure, 1 for success
public static func sendData(toIP: String, onPort : String, withSocketDescriptor : Int32, data : Data) -> Int{
print("sendData called for targetIP: \(toIP):\(onPort) with socket descriptor: \(withSocketDescriptor)")
var target = UnsafeMutablePointer<sockaddr_in>.allocate(capacity: MemoryLayout<sockaddr_in>.size)
target.pointee.sin_family = sa_family_t(AF_INET)
target.pointee.sin_addr.s_addr = inet_addr(toIP)
target.pointee.sin_port = in_port_t(onPort)!
var res = 0
data.withUnsafeBytes { (u8Ptr: UnsafePointer<UInt8>) in
let rawPtr = UnsafeRawPointer(u8Ptr)
withUnsafeMutablePointer(to: &target) {
$0.withMemoryRebound(to: sockaddr.self, capacity: 1) {
let bytesSent = sendto(withSocketDescriptor, rawPtr, data.count, 0, $0, socklen_t(MemoryLayout.size(ofValue: target)))
if bytesSent > 0 {
print(" Sent \(bytesSent) bytes ")
res = 1
}
if bytesSent == -1 {
let strError = String(utf8String: strerror(errno)) ?? "Unknown error code"
let message = "Socket sendto error \(errno) (\(strError))"
print(message)
}
}
}
}
return res
}
public static func closeSocket(socketDescriptor : Int32, clt : UnsafeMutablePointer<sockaddr>) {
print("closing socket descriptor \(socketDescriptor)")
close(socketDescriptor)
clt.deinitialize()
clt.deallocate(capacity: 1)
}
在視圖控制器:
override func viewDidLoad() {
super.viewDidLoad()
var i = 0
for _ in 0..<1000 {
i += connectSendClose(withDescriptor: false) // change withDescriptor to switch socket create/bind method
}
print("Sent \(i) packets")
}
private func connectSendClose(withDescriptor : Bool) -> Int {
let interface = SocketManager.getInterface()
guard let ip = interface.0 else {
print("no relevant interface")
return 0
}
guard let clt = interface.2 else {
print("no addr")
return 0
}
let socketDescriptor = SocketManager.bindSocket(ip: ip, port: "5555", clt: clt, useCltAddr: withDescriptor)
if socketDescriptor == -1 {
print("faild to configure socket")
return 0
}
let serverIP = "59.122.442.9" //dummy IP, test was preformed on actual server
let serverPort = "10025" //dummy port, test was preformed on actual server
let input = 42.13
var value = input
let data = withUnsafePointer(to: &value) {
Data(bytes: UnsafePointer($0), count: MemoryLayout.size(ofValue: input))
}
let res = SocketManager.sendData(toIP: serverIP, onPort: serverPort, withSocketDescriptor: socketDescriptor, data: data)
SocketManager.closeSocket(socketDescriptor: socketDescriptor, clt: clt)
return res
}
這@brianhaak傢伙有幾個帖子聲稱可以連接到移動數據,即使無線網絡連接上。但我無法通過任何文檔來證實這一點。這個想法本身就是違背直覺的。如果我是一個iPhone用戶,並且我有wifi,我希望每個應用程序都使用WiFi連接。我會認爲應用程序偷偷使用移動數據是一個安全問題。 – Sal
@保爾這個特定的應用程序將不會偷偷地使用移動數據 - 用戶將獲得有關數據使用情況的信息。 至於brianhaak的帖子,他指的是使用本機C代碼。 雖然這應該工作(iOS是一個類似Unix的操作系統),但我現在最感興趣的是Swift實現: 據我所知,這些特定的Swift網絡函數是本地代碼的包裝,因此我對於我收到的錯誤感到困惑,並且好奇地想知道我的結果是否存在執行錯誤,或者是否有其他工作出現。 –
我沒有安裝程序來測試您的代碼,但請注意,在您的代碼中將套接字地址「複製」到分配的內存中,「capacity/count」參數表示*項的數量,*不是字節數。 –