Addrinfo#inspect

static VALUE
addrinfo_inspect(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int internet_p;
    VALUE ret;

    ret = rb_sprintf("#<%s: ", rb_obj_classname(self));

    inspect_sockaddr(self, ret);

    if (rai->pfamily && ai_get_afamily(rai) != rai->pfamily) {
        ID id = rsock_intern_protocol_family(rai->pfamily);
        if (id)
            rb_str_catf(ret, " %s", rb_id2name(id));
        else
            rb_str_catf(ret, " PF_\?\?\?(%d)", rai->pfamily);
    }

    internet_p = rai->pfamily == PF_INET;
#ifdef INET6
    internet_p = internet_p || rai->pfamily == PF_INET6;
#endif
    if (internet_p && rai->socktype == SOCK_STREAM &&
        (rai->protocol == 0 || rai->protocol == IPPROTO_TCP)) {
        rb_str_cat2(ret, " TCP");
    }
    else if (internet_p && rai->socktype == SOCK_DGRAM &&
        (rai->protocol == 0 || rai->protocol == IPPROTO_UDP)) {
        rb_str_cat2(ret, " UDP");
    }
    else {
        if (rai->socktype) {
            ID id = rsock_intern_socktype(rai->socktype);
            if (id)
                rb_str_catf(ret, " %s", rb_id2name(id));
            else
                rb_str_catf(ret, " SOCK_\?\?\?(%d)", rai->socktype);
        }

        if (rai->protocol) {
            if (internet_p) {
                ID id = rsock_intern_ipproto(rai->protocol);
                if (id)
                    rb_str_catf(ret, " %s", rb_id2name(id));
                else
                    goto unknown_protocol;
            }
            else {
              unknown_protocol:
                rb_str_catf(ret, " UNKNOWN_PROTOCOL(%d)", rai->protocol);
            }
        }
    }

    if (!NIL_P(rai->canonname)) {
        VALUE name = rai->canonname;
        rb_str_catf(ret, " %s", StringValueCStr(name));
    }

    if (!NIL_P(rai->inspectname)) {
        VALUE name = rai->inspectname;
        rb_str_catf(ret, " (%s)", StringValueCStr(name));
    }

    rb_str_buf_cat2(ret, ">");
    return ret;
}