How to program with SDP (Sockets Direct Protocol) on Linux

I have install the OFED on my computer with Linux OS.

Now, I want to program with SDP.

On some website, it says that the SDP uses the number of 27 for it's protocol family, which is represented by the macro of AF_INET_SDP.

But I could not find the definition.

I defined it in my source code like this:

     #define AF_INET_SDP 27

And then I created the socket like this:

     sockfd = socket( AF_INET_SDP, SOCK_SREAM, IPPROTO_IP);

But, when I run my program, it told me that:

     socket: Address family not supported by protocol

Could someone give me some help?

Thanks!