Discovery Phase of UPnP Architecture using SSDP on C or C++ lanuage on eVC4.0 OS
Hi All,
Good Evening! How are you?
I am facing with one problem. How to implement the SSDP (only discovery phase, not all) of UPnP architecture using C/C++ on eVC 4.0 environment?
i'll write the description below.
SSDP Discovery Program
Target OS: Windows XP
Development Language: Microsoft Visual C++ 6.0
Development Guidelines: Code to be will documented and built-in modules using C/C++. Code will be expanded to support other UpnP functionality and output initially will be textual, but will integrate into the GUI built for the rest of the product, also written in C/C++. Look and feel is not important, as the output at this stage is a test program. All proper error return codes and error handling is expected. Follow on to support control of Internet Gateway Device(s) (IGD) is planned.
Description: Program to display a list of all discovered SSDP UPnP devices. A simple menu with options to initiate discovery, filter and search by device and/or service type and only show root devices. Bare in mind we will want to show all of the discovered device’s or service’s attributes at some point.
Description:
The following is an overview of the messages used to implement SSDP.
SSDP clients discover SSDP services using the reserved local
administrative scope multicast address 239.255.255.250 over the SSDP port
(1900/UDP).
UPnP and SSDP listen on port 5000 for TCP connections and UDP port 1900 for
incoming datagram packets. Since these are not commonly used ports, most
personal firewalls and firewall appliances will block connections to these
ports.
For brevity's sake the SSDP reserved local administrative scope
multicast address and port will be referred to as the SSDP multicast
channel/Port.
Discovery occurs when a SSDP client multicasts a HTTP UDP discovery
request to the SSDP multicast channel/Port. SSDP services listen to the SSDP
multicast channel/Port in order to hear such discovery
requests. If a SSDP service hears a HTTP UDP discovery request that
matches the service it offers then it will respond using a unicast
HTTP UDP response.
SSDP services may send HTTP UDP notification announcements to the
SSDP multicast channel/port to announce their presence.
Hence two types of SSDP requests will be sent across the SSDP
multicast channel/port. The first are discovery requests, a SSDP
client looking for SSDP services. The second are presence
announcements, a SSDP service announcing its presence.
ssdp:alive -- SSDP services may declare their presence on the network by
sending a [GENA] NOTIFY method using the NTS value ssdp:alive to the SSDP
multicast channel/port.
For brevity's sake HTTP NOTIFY methods with the NTS value ssdp:alive
will be referred to as ssdp:alive requests.
When a ssdp:alive request is received whose USN matches the USN of
an entry already in the SSDP client's cache then all information
regarding that USN is to be replaced with the information on the
ssdp:alive request. Hence ssdp:alive requests can be used to update
location information and prevent cache entries from expiring.
ssdp:byebye -- SDP services may declare their intention to cease operating
by sending a [GENA] NOTIFY method using the NTS value ssdp:byebye to the
SSDP multicast channel/port.
Since 1 week i am facing so many problems with this problem. Could you please let me know how to implement this, and how to start? I would really appreciate your feedback on this.
Thanks
Ravi.
