NAME

inet6_rthdr_space, inet6_rthdr_init, inet6_rthdr_add, inet6_rthdr_lasthop, inet6_rthdr_reverse, inet6_rthdr_segments, inet6_rthdr_getaddr, inet6_rthdr_getflags — IPv6 Routing Header Options manipulation

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

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

size_t
inet6_rthdr_space(int type, int segments);

struct cmsghdr *
inet6_rthdr_init(void *bp, int type);

int
inet6_rthdr_add(struct cmsghdr *cmsg, const struct in6_addr *addr, unsigned int flags);

int
inet6_rthdr_lasthop(struct cmsghdr *cmsg, unsigned int flags);

int
inet6_rthdr_reverse(const struct cmsghdr *in, struct cmsghdr *out);

int
inet6_rthdr_segments(const struct cmsghdr *cmsg);

struct in6_addr *
inet6_rthdr_getaddr(struct cmsghdr *cmsg, int index);

int
inet6_rthdr_getflags(const struct cmsghdr *cmsg, int index);

DESCRIPTION

RFC2292 IPv6 advanced API defines eight functions that the application calls to build and examine a Routing header. Four functions build a Routing header:

inet6_rthdr_space()

return #bytes required for ancillary data

inet6_rthdr_init()

initialize ancillary data for Routing header

inet6_rthdr_add()

add IPv6 address & flags to Routing header

inet6_rthdr_lasthop()

specify the flags for the final hop

Four functions deal with a returned Routing header:

inet6_rthdr_reverse()

reverse a Routing header

inet6_rthdr_segments()

return #segments in a Routing header

inet6_rthdr_getaddr()

fetch one address from a Routing header

inet6_rthdr_getflags()

fetch one flag from a Routing header

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_rthdr_space() returns 0 on errors.

inet6_rthdr_add(), inet6_rthdr_lasthop() and inet6_rthdr_reverse() return 0 on success, and returns -1 on error.

inet6_rthdr_init() and inet6_rthdr_getaddr() return NULL on error.

inet6_rthdr_segments() and inet6_rthdr_getflags() return -1 on error.

EXAMPLES

RFC2292 gives comprehensive examples in chapter 8.

SEE ALSO

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.

HISTORY

The implementation first appeared in KAME advanced networking kit.

STANDARDS

The functions are documented in “Advanced Sockets API for IPv6” (RFC2292).

BUGS

The text was shamelessly copied from RFC2292.

inet6_rthdr_reverse() is not implemented yet.