LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/types.h>
     #include <netinet/in.h>

     int
     inet6_option_space(int nbytes);

     int
     inet6_option_init(void *bp, struct cmsghdr **cmsgp, int type);

     int
     inet6_option_append(struct cmsghdr *cmsg, const u_int8_t *typep,
         int multx, int plusy);

     u_int8_t *
     inet6_option_alloc(struct cmsghdr *cmsg, int datalen, int multx,
         int plusy);

     int
     inet6_option_next(const struct cmsghdr *cmsg, u_int8_t **tptrp);

     int
     inet6_option_find(const struct cmsghdr *cmsg, u_int8_t **tptrp,
         int type);

DESCRIPTION

     Building and parsing the Hop-by-Hop and Destination options is compli-
     cated due to alignment constranints, padding and ancillary data manipula-
     tion.  RFC2292 defines a set of functions to help the application.  The
     function prototypes for these functions are all in the <netinet/in.h>
     header.

     The full description of these functions is available in RFC2292.

DIAGNOSTICS

     inet6_option_init() and inet6_option_append() return 0 on success or -1
     on an error.

     inet6_option_alloc() returns NULL on an error.

     On errors, inet6_option_next() and inet6_option_find() return -1 setting
     *tptrp to non NULL value.

EXAMPLES

     RFC2292 gives comprehensive examples in chapter 6.

SEE ALSO

     W. Stevens and M. Thomas, Advanced Sockets API for IPv6, RFC2292,
     February 1998.