我正在尝试使用Android4.x VPN服务与内部以太网服务器建立VPN隧道.IP地址是Internet上的一个全局IP，这是问题所在:
1.我使用TCP dump来捕获数据包，在建立VPN Service.build之后，无法在以前连接到服务器的隧道中传输任何tcp数据包。
2.建立建立后，我得到一个fileDescriptor，它不能写任何字节(EINVAL错误)，也不能读任何字节(长度= 0)。
3.我使用套接字隧道与服务器通信并发送PPTP数据包，在启动控制请求，呼出调用请求之后，服务器返回正确的信息，然后通过PPP LCP协议(protocol)传输配置信息。但是，我不知道下一步该怎么做，如何获取PPP LCP数据包，它不是来自套接字，文件描述符无法读取或写入任何内容。
请帮忙，谢谢大家!
private static ParcelFileDescriptor tunPFD;
private boolean run(InetSocketAddress server) throws Exception {
SocketChannel tunnel = null;
boolean connected = false;
try {
// Create a DatagramChannel as the VPN tunnel.
tunnel = SocketChannel.open();
// Protect the tunnel before connecting to avoid loopback.
if (!protect(tunnel.socket())) {
// throw new IllegalStateException("Cannot protect the tunnel");
System.out.println("can't protected");
}
// Connect to the server.
tunnel.connect(server);
System.out.println("connected");
// For simplicity, we use the same thread for both reading and
// writing. Here we put the tunnel into non-blocking mode.
tunnel.configureBlocking(true);
System.out.println("PFD success");
// Authenticate and configure the virtual network interface.
handshake(tunnel);
System.out.println("handshake");
Thread.sleep(1000);
ToyVpnService.Builder builder = new ToyVpnService.Builder();
builder.setSession("ToyVPN").addAddress("xxx.xxx.xxx.xxx", 32)
.addRoute("1.0.0.0", 8)
.addRoute("2.0.0.0", 7)
.addRoute("4.0.0.0", 6)
.addRoute("8.0.0.0", 7)
.addRoute("11.0.0.0", 8)
.addRoute("12.0.0.0", 6)
.addRoute("16.0.0.0", 4)
.addRoute("32.0.0.0", 3)
.addRoute("64.0.0.0", 2)
.addRoute("139.0.0.0", 8)
.addRoute("140.0.0.0", 6)
.addRoute("144.0.0.0", 4)
.addRoute("160.0.0.0", 5)
.addRoute("168.0.0.0", 6)
.addRoute("172.0.0.0", 12)
.addRoute("172.32.0.0", 11)
.addRoute("172.64.0.0", 10)
.addRoute("172.128.0.0", 9)
.addRoute("173.0.0.0", 8)
.addRoute("174.0.0.0", 7)
.addRoute("176.0.0.0", 4)
.addRoute("192.0.0.0", 9)
.addRoute("192.128.0.0", 11)
.addRoute("192.160.0.0", 13)
.addRoute("192.169.0.0", 16)
.addRoute("192.170.0.0", 15)
.addRoute("192.172.0.0", 14)
.addRoute("192.176.0.0", 12)
.addRoute("192.192.0.0", 10)
.addRoute("193.0.0.0", 8)
.addRoute("194.0.0.0", 7)
.addRoute("196.0.0.0", 6)
.addRoute("200.0.0.0", 5)
.addRoute("208.0.0.0", 4)
.addRoute("224.0.0.0", 4)
.addRoute("240.0.0.0", 5)
.addRoute("248.0.0.0", 6)
.addRoute("252.0.0.0", 7)
.addRoute("254.0.0.0",8)
.addDnsServer("xxx.xxx.xxx.xxx")
.establish();
if (tunPFD == null) {
tunPFD = builder.establish();
if (tunPFD == null) {
System.out.println("stop");
stopSelf();
}
}
// Now we are connected. Set the flag and show the message.
connected = true;
mHandler.sendEmptyMessage(R.string.connected);
tunnel.configureBlocking(false);
// Packets to be sent are queued in this input stream.
FileInputStream in = new FileInputStream(tunPFD.getFileDescriptor());
// Packets received need to be written to this output stream.
FileOutputStream out = new FileOutputStream(tunPFD.getFileDescriptor());
int length = 0;
int count = 0;
while ((length == 0) && (count < 5000)) {
length = in.read(pptp.dataPack);
Thread.sleep(200);
count += 200;
System.out.println(count);
}
System.out.printf("read fd%d\n", tunPFD.getFd());
System.out.println(length);
System.out.println("write fd");
tunnel.write(pptp.packet);
Thread.sleep(2000);
} catch (InterruptedException e) {
throw e;
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
tunnel.close();
} catch (Exception e) {
// ignore
}
}
return connected;
}
private void handshake(SocketChannel tunnel) throws Exception {
// To build a secured tunnel, we should perform mutual authentication
// and exchange session keys for encryption. To keep things simple in
// this demo, we just send the shared secret in plaintext and wait
// for the server to send the parameters.
// Allocate the buffer for handshaking.
// Control messages always start with zero.
tunnel.write(pptp.Start_Control_Req_Package());
// Wait for the parameters within a limited time.
Thread.sleep(100);
// Normally we should not receive random packets.
int length = tunnel.read(pptp.getEmptyPackage());
if (length <= 0 || pptp.getPacketType() != 2) {
System.out.println("start reply fail");
return;
}
tunnel.write(pptp.Outgoing_Call_Req_Package());
Thread.sleep(100);
length = tunnel.read(pptp.getEmptyPackage());
if (length <= 0 || pptp.getPacketType() != 8) {
System.out.println("outgoing reply fail");
return;
}
System.out.println("succeed");
}
pptp.Start_Control_Req_Package()保证生成一个Start-Control-Request数据包，该数据包可以由服务器答复。我已经从tcpdump确认了。 Outgoing_Call相同。然后服务器发回PPP_LCP数据包以请求配置，我不知道如何捕获它并发回配置。
最佳答案
看着您的代码片段，我看到了几件事。您是否修改了握手调用？如果不是这样，则可能会在构建器上两次调用Establishment()。假设未修改toyvpn示例中的握手和配置方法时，您在代码段中调用“建立”时，您可能会吹掉正确配置的接口(interface)，至少与我所看到的看似与 Vanilla 交谈的接口(interface)与服务器通信toyvpn应用程序的服务器配置为向其发送正确的配置。因此，您正在尝试从配置错误的调谐设备中进行读取和写入。
private void handshake(DatagramChannel tunnel) throws Exception {
// To build a secured tunnel, we should perform mutual authentication
// and exchange session keys for encryption. To keep things simple in
// this demo, we just send the shared secret in plaintext and wait
// for the server to send the parameters.
// Allocate the buffer for handshaking.
ByteBuffer packet = ByteBuffer.allocate(1024);
// Control messages always start with zero.
packet.put((byte) 0).put(mSharedSecret).flip();
// Send the secret several times in case of packet loss.
for (int i = 0; i < 3; ++i) {
packet.position(0);
tunnel.write(packet);
}
packet.clear();
// Wait for the parameters within a limited time.
for (int i = 0; i < 50; ++i) {
Thread.sleep(100);
// Normally we should not receive random packets.
int length = tunnel.read(packet);
if (length > 0 && packet.get(0) == 0) {
configure(new String(packet.array(), 1, length - 1).trim());
return;
}
}
throw new IllegalStateException("Timed out");
}
private void configure(String parameters) throws Exception {
// If the old interface has exactly the same parameters, use it!
if (mInterface != null && parameters.equals(mParameters)) {
Log.i(TAG, "Using the previous interface");
return;
}
// Configure a builder while parsing the parameters.
Builder builder = new Builder();
for (String parameter : parameters.split(" ")) {
String[] fields = parameter.split(",");
try {
switch (fields[0].charAt(0)) {
case 'm':
builder.setMtu(Short.parseShort(fields[1]));
break;
case 'a':
builder.addAddress(fields[1], Integer.parseInt(fields[2]));
break;
case 'r':
builder.addRoute(fields[1], Integer.parseInt(fields[2]));
break;
case 'd':
builder.addDnsServer(fields[1]);
break;
case 's':
builder.addSearchDomain(fields[1]);
break;
}
} catch (Exception e) {
throw new IllegalArgumentException("Bad parameter: " + parameter);
}
}
// Close the old interface since the parameters have been changed.
try {
mInterface.close();
} catch (Exception e) {
// ignore
}
// Create a new interface using the builder and save the parameters.
mInterface = builder.setSession(mServerAddress)
.setConfigureIntent(mConfigureIntent)
.establish();
mParameters = parameters;
Log.i(TAG, "New interface: " + parameters);
}
}
可能有三次，因为第二次未使用构建器的返回值，但根据文档，它将为tun设备返回新的fd。我可能会建议将为配置vpn接口(interface)添加的更改移到ToyVpnService示例中的configure方法中。在大多数情况下，您所做的大部分更改似乎都集中在配置上。您可以尝试从ParcelFileDescriptor接口(interface)添加对canCheckError/checkError的调用，也可以使用getFd()并调用valid以在尝试读取和写入tun设备时检查tun设备的描述符是否实际上是有效的fd。
希望对您有所帮助。
关于android - Android开发中，来自VPNService.buider的FileDescriptor无法写入和读取，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/21770242/