No, sa_data is a minimum size, not a maximum. For unix domain sockets you should look at the definition of sockaddr_un which has char sun_path[104]; but again, that's a minimum reserved size and if you allocate a larger size you can use sockets with longer names.
And, the 14 character limit in old unix was for individual path components, whereas unix domain sockets contain complete paths, so the 14 character limit was never relevant for unix domain socket addresses.
And, the 14 character limit in old unix was for individual path components, whereas unix domain sockets contain complete paths, so the 14 character limit was never relevant for unix domain socket addresses.