void slirp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len);
/* you must provide the following functions: */
-int slirp_can_output(void *opaque);
void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len);
int slirp_add_hostfwd(Slirp *slirp, int is_udp,