Address/port number comparison

If you want to touch AF dependent members of sockaddr_*
convert to text format by getnameinfo(), compare as strings.
If you allow to touch AF dependent members
nothing should be changed, although you should specify all possible cases.

if (sa1->sa_len != sa2->sa_len)
        return 0;  /* different */
if (getnameinfo(sa1, sa1->sa_len, h1, sizeof(h1),
    NULL, 0, NI_NUMERICHOST) != 0)
        return -1;  /* error */
if (getnameinfo(sa2, sa2->sa_len, h2, sizeof(h2),
    NULL, 0, NI_NUMERICHOST) != 0)
        return -1;  /* error */
if (strcmp(h1, h2) == 0)
        return 1;  /* same */
else
        return 0;  /* different */