使用udp发送搜索广播请求

M-SEARCH * HTTP/1.1
HOST: 239.255.255.250:1900 # 固定地址和端口，广播
MAN: "ssdp:discover"
MX: 3
ST: ssdp:all    # 设备类型，这里选择所有. Search Target缩写，用于请求中

可选的upnp设备类型有哪些？

upnp搜索响应

# 公司里的TCL电视机
HOST: 239.255.255.250:1900                                                                                                CACHE-CONTROL: max-age=66                                                                   LOCATION: http://192.168.40.70:49152/description.xml                                                  OPT: "http://schemas.upnp.org/upnp/1/0/"; ns=01                                                 01-NLS: 668792f0-1dd2-11b2-a401-fb0f9a8a7d29                                                   NT: urn:schemas-upnp-org:service:RenderingControl:1    # Notification Type，表示设备或服务的类型                                           
NTS: ssdp:alive                                                         
SERVER: Linux/4.9.113 HTTP/1.0                                                                    X-User-Agent: redsonic                                                                      USN: uuid:4149b0d2-d339-de03-f814-f40116f02d93::urn:schemas-upnp-org:service:RenderingControl:1  
# USN: USN（Unique Service Name）字段用于唯一标识网络中的设备和服务。USN字段由设备的UUID和服务类型或设备类型组成，以便在网络中唯一标识一个设备及其服务。

# 上面这台设备是一台TCL的电视机，返回的响应有多条，NT的值不同，有“upnp:rootdevice”、“urn:schemas-upnp-org:service:ConnectionManager:1”、“urn:schemas-upnp-org:service:RenderingControl:1”， NT也可能是uuid，唯一标识符，这种情况下，NT字段表示的是设备的唯一实例，而不是设备或服务的类型。

# NTS: NTS 是 Notification Sub Type（通知子类型）的缩写。NTS字段用于标识SSDP（Simple Service Discovery Protocol）通知消息的具体类型，指示设备的当前状态变化。可选 ssdp:alive、ssdp:byebye、ssdp:update

其中返回的结果中Location xml内容

<?xml version="1.0"?>
<root xmlns="urn:schemas-upnp-org:device-1-0">
<specVersion>
<major>1</major>
<minor>0</minor>
</specVersion>
<device>
<deviceType>urn:schemas-upnp-org:device:MediaRenderer:1</deviceType>
<presentationURL>/</presentationURL>
<friendlyName>TCL 65V2-PRO-5CF9(192.168.40.70)</friendlyName>
<dlna:X_DLNADOC xmlns:dlna="urn:schemas-dlna-org:device-1-0">DMR-1.50</dlna:X_DLNADOC>
<UDN>uuid:4149b0d2-d339-de03-f814-f40116f02d93</UDN>
<serviceList>
<service>
<serviceType>urn:schemas-upnp-org:service:AVTransport:1</serviceType>
<serviceId>urn:upnp-org:serviceId:AVTransport</serviceId>
<controlURL>_urn:schemas-upnp-org:service:AVTransport_control</controlURL>
<SCPDURL>_urn:schemas-upnp-org:service:AVTransport_scpd.xml</SCPDURL>
<eventSubURL>_urn:schemas-upnp-org:service:AVTransport_event</eventSubURL>
</service>
<service>
<serviceType>urn:schemas-upnp-org:service:RenderingControl:1</serviceType>
<serviceId>urn:upnp-org:serviceId:RenderingControl</serviceId>
<controlURL>_urn:schemas-upnp-org:service:RenderingControl_control</controlURL>
<SCPDURL>_urn:schemas-upnp-org:service:RenderingControl_scpd.xml</SCPDURL>
<eventSubURL>_urn:schemas-upnp-org:service:RenderingControl_event</eventSubURL>
</service>
<service>
<serviceType>urn:schemas-upnp-org:service:ConnectionManager:1</serviceType>
<serviceId>urn:upnp-org:serviceId:ConnectionManager</serviceId>
<SCPDURL>_urn:schemas-upnp-org:service:ConnectionManager_scpd.xml</SCPDURL>
<controlURL>_urn:schemas-upnp-org:service:ConnectionManager_control</controlURL>
<eventSubURL>_urn:schemas-upnp-org:service:ConnectionManager_event</eventSubURL>
</service>
</serviceList>
<manufacturer>Microsoft Corporation</manufacturer>
<manufacturerURL>http://www.microsoft.com</manufacturerURL>
<modelDescription>Media Renderer</modelDescription>
<modelName>Windows Media Player</modelName>
<modelURL>http://go.microsoft.com/fwlink/?Linkld=105927</modelURL>
</device>
<URLBase>http://192.168.40.70:49152</URLBase>
</root>