static int dns_transaction_make_packet(DnsTransaction *t) {
        _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
        int r;

        assert(t);

        if (t->sent)
                return 0;

        r = dns_packet_new_query(&p, t->scope->protocol, 0);
        if (r < 0)
                return r;

        r = dns_scope_good_key(t->scope, t->key);
        if (r < 0)
                return r;
        if (r == 0)
                return -EDOM;

        r = dns_packet_append_key(p, t->key, NULL);
        if (r < 0)
                return r;

        DNS_PACKET_HEADER(p)->qdcount = htobe16(1);
        DNS_PACKET_HEADER(p)->id = t->id;

        t->sent = p;
        p = NULL;

        return 0;
}
static int dns_transaction_make_packet(DnsTransaction *t) {
        _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
        unsigned n, added = 0;
        int r;

        assert(t);

        if (t->sent)
                return 0;

        r = dns_packet_new_query(&p, t->scope->protocol, 0);
        if (r < 0)
                return r;

        for (n = 0; n < t->question->n_keys; n++) {
                r = dns_scope_good_key(t->scope, t->question->keys[n]);
                if (r < 0)
                        return r;
                if (r == 0)
                        continue;

                r = dns_packet_append_key(p, t->question->keys[n], NULL);
                if (r < 0)
                        return r;

                added++;
        }

        if (added <= 0)
                return -EDOM;

        DNS_PACKET_HEADER(p)->qdcount = htobe16(added);
        DNS_PACKET_HEADER(p)->id = t->id;

        t->sent = p;
        p = NULL;

        return 0;
}