无法使用SSDP接收正确的UDP数据包
我试图在我的Android应用程序中实现一个非常简单的SSDP功能。
我的应用程序发送一些包含相关M-SEARCH消息的UDP数据包给广播地址，没有任何问题。 问题是，我应该从运行UPNP服务器的其他设备获得正确的响应。 出于某种原因，我只收到从我的Android设备发回的完全相同的数据包。
MainActivity.java
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
WifiManager wm = (WifiManager)getSystemService(Context.WIFI_SERVICE);
WifiManager.MulticastLock multicastLock = wm.createMulticastLock("multicastLock");
multicastLock.setReferenceCounted(true);
multicastLock.acquire();
setContentView(R.layout.activity_main);
((Button)this.findViewById(R.id.btnSendSSDPSearch)).setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnSendSSDPSearch:
new Thread(new Runnable() {
@Override
public void run() {
SendMSearchMessage();
}
}).start();
default:
break;
}
}
private void SendMSearchMessage() {
SSDPSearchMsg searchContentDirectory = new SSDPSearchMsg(SSDPConstants.ST_ContentDirectory);
SSDPSearchMsg searchAVTransport = new SSDPSearchMsg(SSDPConstants.ST_AVTransport);
SSDPSearchMsg searchProduct = new SSDPSearchMsg(SSDPConstants.ST_Product);
SSDPSocket sock;
try {
sock = new SSDPSocket();
for (int i = 0; i < 2; i++) {
sock.send(searchContentDirectory.toString());
sock.send(searchAVTransport.toString());
sock.send(searchProduct.toString());
}
while (true) {
DatagramPacket dp = sock.receive(); //Here, I only receive the same packets I initially sent above
String c = new String(dp.getData());
System.out.println(c);
}
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e("M-SEARCH", e.getMessage());
}
实际完成UDP数据包传输的SSDPSocket.java
public class SSDPSocket {
SocketAddress mSSDPMulticastGroup;
MulticastSocket mSSDPSocket;
InetAddress broadcastAddress;
public SSDPSocket() throws IOException {
mSSDPSocket = new MulticastSocket(55325); //Bind some random port for receiving datagram
broadcastAddress = InetAddress.getByName(SSDPConstants.ADDRESS);
mSSDPSocket.joinGroup(broadcastAddress);
}
/* Used to send SSDP packet */
public void send(String data) throws IOException {
DatagramPacket dp = new DatagramPacket(data.getBytes(), data.length(),
broadcastAddress,SSDPConstants.PORT);
mSSDPSocket.send(dp);
}
/* Used to receive SSDP packet */
public DatagramPacket receive() throws IOException {
byte[] buf = new byte[1024];
DatagramPacket dp = new DatagramPacket(buf, buf.length);
mSSDPSocket.receive(dp);
return dp;
}
public void close() {
if (mSSDPSocket != null) {
mSSDPSocket.close();
}
}
}
用于构建SSDP的SSDPSearchMsg.java广播字符串（可能与我遇到的问题无关，但为了以防万一）
public class SSDPSearchMsg {
static final String HOST = "Host:" + SSDP.ADDRESS + ":" + SSDP.PORT;
static final String MAN = "Man:ssdp:discover";
static final String NEWLINE = System.getProperty("line.separator");
int mMX = 3; /* seconds to delay response */
String mST; /* Search target */
public SSDPSearchMsg(String ST) {
mST = ST;
}
public int getmMX() {
return mMX;
}
public void setmMX(int mMX) {
this.mMX = mMX;
}
public String getmST() {
return mST;
}
public void setmST(String mST) {
this.mST = mST;
}
@Override
public String toString() {
StringBuilder content = new StringBuilder();
content.append(SSDP.SL_MSEARCH).append(NEWLINE);
content.append(HOST).append(NEWLINE);
content.append(MAN).append(NEWLINE);
content.append(mST).append(NEWLINE);
content.append("MX:" + mMX).append(NEWLINE);
content.append(NEWLINE);
return content.toString();
}
}
SSDPConstants.java
public class SSDPConstants {
/* New line definition */
public static final String NEWLINE = "rn";
public static final String ADDRESS = "239.255.255.250";
public static final int PORT = 1900;
/* Definitions of start line */
public static final String SL_NOTIFY = "NOTIFY * HTTP/1.1";
public static final String SL_MSEARCH = "M-SEARCH * HTTP/1.1";
public static final String SL_OK = "HTTP/1.1 200 OK";
/* Definitions of search targets */
public static final String ST_RootDevice = "St: rootdevice";
public static final String ST_ContentDirectory = "St: urn:schemas-upnp-org:service:ContentDirectory:1";
public static final String ST_AVTransport = "St: urn:schemas-upnp-org:service:AVTransport:1";
public static final String ST_Product = "St: urn:av-openhome-org:service:Product:1";
/* Definitions of notification sub type */
public static final String NTS_ALIVE = "NTS:ssdp:alive";
public static final String NTS_BYE = "NTS:ssdp:byebye";
public static final String NTS_UPDATE = "NTS:ssdp:update";
}
我还确保清单包含相关权限：
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
我正在实际设备上测试应用程序，而不是仿真器上。
任何援助将不胜感激。
编辑评论：
多播本身应该没有问题。 我已经下载了一个名为BubbleUPNP的应用程序来测试SSDP功能。 果然，wireshark可以正确捕获从手机发送到SSDP协议中的广播地址的所有消息：
M-SEARCH * HTTP/1.1
Man: "ssdp:discover"
Mx: 3
Host: 239.255.255.250:1900
St: urn:schemas-upnp-org:service:AVTransport:1
和回应
HTTP/1.1 200 OK
ST:urn:schemas-upnp-org:service:ContentDirectory:1
USN:uuid:d5829e90-73ce-4213-9ad1-4e75dbdd0232::urn:schemas-upnp-org:service:ContentDirectory:1
Location:http://10.175.95.4:2869/upnphost/udhisapi.dll?content=uuid:d5829e90-73ce-4213-9ad1-4e75dbdd0232
OPT:"http://schemas.upnp.org/upnp/1/0/"; ns=01
01-NLS:05f3dd08b4b4b5aafa1fe983fa447f49
Cache-Control:max-age=900
Server:Microsoft-Windows-NT/5.1 UPnP/1.0 UPnP-Device-Host/1.0
所以，这是毫无疑问的，这是一个实施问题。 设备没有问题。
奇怪的。 我解决了这个问题，但我真的不确定它是如何工作的。
以下是我所做的一些更改：
我没有分配一个固定端口，而是动态分配一个可用端口。
public class SSDPSocket {
SocketAddress mSSDPMulticastGroup;
MulticastSocket mSSDPSocket;
InetAddress broadcastAddress;
public SSDPSocket() throws IOException {
mSSDPSocket = new MulticastSocket();
broadcastAddress = InetAddress.getByName(SSDPConstants.ADDRESS);
mSSDPSocket.joinGroup(broadcastAddress);
}
...
}
我还更改了M-Search消息结构，包括其顺序。
public class SSDPSearchMsg {
static final String HOST = "Host: " + SSDPConstants.ADDRESS + ":" + SSDPConstants.PORT;
static final String MAN = "Man: "ssdp:discover"";
static final String NEWLINE = "rn";
int mMX = 3; /* seconds to delay response */
String mST; /* Search target */
public SSDPSearchMsg(String ST) {
mST = ST;
}
public int getmMX() {
return mMX;
}
public void setmMX(int mMX) {
this.mMX = mMX;
}
public String getmST() {
return mST;
}
public void setmST(String mST) {
this.mST = mST;
}
@Override
public String toString() {
StringBuilder content = new StringBuilder();
content.append(SSDPConstants.SL_MSEARCH).append(NEWLINE);
content.append(MAN).append(NEWLINE);
content.append("Mx: " + mMX).append(NEWLINE);
content.append(HOST).append(NEWLINE);
content.append(mST).append(NEWLINE);
content.append(NEWLINE);
return content.toString();
}
}
一切突然发生作用。 为什么它的作品超越了我。 据我所知，我之前的实现遵循SSDP协议。
在可能的答案是，你可能有一个“旧”设备。 显然组播（来自Java）在Android 2.3.7之前已经被打破
参考：https：//stackoverflow.com/a/9836464/139985
另一种可能性是它是一个特定于设备的问题; 例如像这样：https://stackoverflow.com/a/3714848/139985。 （我不是说这是一个具体的问题......）
另一个是在内核配置中禁用多播：http://code.google.com/p/android/issues/detail?id=51195
似乎有多种不同的原因使多播不能在各种Android设备上工作......
我遵循你的代码并将一些单词改为大写。 有用。
static final String HOST = "HOST: " + SSDPConstants.ADDRESS + ":" + SSDPConstants.PORT;
static final String MAN = "MAN: "ssdp:discover"";
不需要更改MSEARCH消息中的顺序。
链接地址: http://www.djcxy.com/p/70481.html