Open a socket with the name socket:[4023]

I'm working on a linux system and want to open a socket for IPC. The process ID of the process I want to communicate with is 123. The process already opened the socket. I know that it is possible to send the file descriptor via unix domain sockets or dbus. But:

Is there also a way to open the socket by the name gotten from /proc/123/fd/15 ? If I call “ls -l” in /proc/123/fd/ the symlink looks like “15 -> socket:[4023]”. Is there a way to open “socket:[4023]” ?

Edit: I am tried to do this in C.

Regards, Maz