#include <netinet/in.h>int
inet6_opt_init(void *extbuf, socklen_t extlen);
int
inet6_opt_append(void *extbuf, socklen_t extlen, int offset, u_int8_t type, socklen_t len, u_int8_t align, void **databufp);
int
inet6_opt_finish(void *extbuf, socklen_t extlen, int offset);
int
inet6_opt_set_val(void *databuf, int offset, void *val, socklen_t vallen);
int
inet6_opt_next(void *extbuf, socklen_t extlen, int offset, u_int8_t *typep, socklen_t *lenp, void **databufp);
int
inet6_opt_find(void *extbuf, socklen_t extlen, int offset, u_int8_t type, socklen_t *lenp, void **databufp);
int
inet6_opt_get_val(void *databuf, socklen_t offset, void *val, socklen_t vallen);