| INET6_OPTION_SPACE(3) | Library Functions Manual | INET6_OPTION_SPACE(3) |
inet6_option_space,
inet6_option_init,
inet6_option_append,
inet6_option_alloc,
inet6_option_next,
inet6_option_find — IPv6
Hop-by-Hop and Destination Options manipulation
Standard C Library (libc, -lc)
#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);
Building and parsing the Hop-by-Hop and Destination options is
complicated due to alignment constranints, padding and ancillary data
manipulation. 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.
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.
RFC2292 gives comprehensive examples in chapter 6.
W. Stevens and M. Thomas, Advanced Sockets API for IPv6, RFC2292, February 1998.
S. Deering and R. Hinden, Internet Protocol, Version 6 (IPv6) Specification, RFC2460, December 1998.
The implementation first appeared in KAME advanced networking kit.
The functions are documented in “Advanced Sockets API for IPv6” (RFC2292).
| December 10, 1999 | macOS 15.2 |