extern int slirp_user_read(int fd, void *buf, int len, struct slirp_data *pri);
extern int slirp_user_write(int fd, void *buf, int len,
extern int slirp_user_read(int fd, void *buf, int len, struct slirp_data *pri);
extern int slirp_user_write(int fd, void *buf, int len,