new_conn(struct conntrack *ct, struct dp_packet *pkt, struct conn_key *key,
         long long now, uint32_t tp_id)
{
    return l4_protos[key->nw_proto]->new_conn(ct, pkt, now, tp_id);
}
new_conn(struct conntrack *ct, struct dp_packet *pkt, struct conn_key *key,
         long long now, uint32_t tp_id)
{
    return l4_protos[key->nw_proto]->new_conn(ct, pkt, now, tp_id);
}