When you use sockaddr_foo for addresses, there are usually lots of type casts obscuring the code, and it's easy to forget that a struct sockaddr isn't big enough for a Unix socket path (you need a struct sockaddr_storage for that).

Consider adding a GibberAddress struct or union which contains one of each sockaddr struct, including sockaddr_storage:

typedef union {
    struct sockaddr generic;
    struct sockaddr_storage storage;
    struct sockaddr_inet ipv4;
    struct sockaddr_inet6 ipv6;
    struct sockaddr_unix un;
} GibberSockAddr;

Gabble has a union similar to this one internally, although the necessity to #ifdef various bits of the union for different OSs (no Unix sockets on Windows) may mean we can't have the union appear directly in an ABI-stable header file.

libnice has a NiceAddress type which could be worth investigating for this, although that one is unlikely to support Unix sockets. I believe Avahi has a similar thing too.