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.\"     $Id: inet6_rthdr_space.3,v 1.3 2005/01/19 00:30:03 majka Exp $
.\" $FreeBSD: src/lib/libc/net/inet6_rthdr_space.3,v 1.1.2.5 2001/08/17 15:42:38 ru Exp $
.\"
.Dd December 10, 1999
.Dt INET6_RTHDR_SPACE 3
.Os
.\"
.Sh NAME
.Nm inet6_rthdr_space ,
.Nm inet6_rthdr_init ,
.Nm inet6_rthdr_add ,
.Nm inet6_rthdr_lasthop ,
.Nm inet6_rthdr_reverse ,
.Nm inet6_rthdr_segments ,
.Nm inet6_rthdr_getaddr ,
.Nm inet6_rthdr_getflags
.Nd IPv6 Routing Header Options manipulation
.\"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <netinet/in.h>
.Ft size_t
.Fn inet6_rthdr_space "int type" "int segments"
.Ft "struct cmsghdr *"
.Fn inet6_rthdr_init "void *bp" "int type"
.Ft int
.Fn inet6_rthdr_add "struct cmsghdr *cmsg" "const struct in6_addr *addr" "unsigned int flags"
.Ft int
.Fn inet6_rthdr_lasthop "struct cmsghdr *cmsg" "unsigned int flags"
.Ft int
.Fn inet6_rthdr_reverse "const struct cmsghdr *in" "struct cmsghdr *out"
.Ft int
.Fn inet6_rthdr_segments "const struct cmsghdr *cmsg"
.Ft "struct in6_addr *"
.Fn inet6_rthdr_getaddr "struct cmsghdr *cmsg" "int index"
.Ft int
.Fn inet6_rthdr_getflags "const struct cmsghdr *cmsg" "int index"
.\"
.Sh 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:
.Bl -hang
.It Fn inet6_rthdr_space
return #bytes required for ancillary data
.It Fn inet6_rthdr_init
initialize ancillary data for Routing header
.It Fn inet6_rthdr_add
add IPv6 address & flags to Routing header
.It Fn inet6_rthdr_lasthop
specify the flags for the final hop
.El
.Pp
Four functions deal with a returned Routing header:
.Bl -hang
.It Fn inet6_rthdr_reverse
reverse a Routing header
.It Fn inet6_rthdr_segments
return #segments in a Routing header
.It Fn inet6_rthdr_getaddr
fetch one address from a Routing header
.It Fn inet6_rthdr_getflags
fetch one flag from a Routing header
.El
.Pp
The function prototypes for these functions are all in the
.Aq Li netinet/in.h
header.
.Pp
The full description of these functions is available in RFC2292.
.\"
.Sh DIAGNOSTICS
.Fn inet6_rthdr_space
returns 0 on errors.
.Pp
.Fn inet6_rthdr_add ,
.Fn inet6_rthdr_lasthop
and
.Fn inet6_rthdr_reverse
return 0 on success, and returns -1 on error.
.Pp
.Fn inet6_rthdr_init
and
.Fn inet6_rthdr_getaddr
return
.Dv NULL
on error.
.Pp
.Fn inet6_rthdr_segments
and
.Fn inet6_rthdr_getflags
return -1 on error.
.\"
.Sh EXAMPLES
RFC2292 gives comprehensive examples in chapter 8.
.\"
.Sh SEE ALSO
.Rs
.%A W. Stevens
.%A M. Thomas
.%T "Advanced Sockets API for IPv6"
.%N RFC2292
.%D February 1998
.Re
.Rs
.%A S. Deering
.%A R. Hinden
.%T "Internet Protocol, Version 6 (IPv6) Specification"
.%N RFC2460
.%D December 1998
.Re
.\"
.Sh HISTORY
The implementation first appeared in KAME advanced networking kit.
.\"
.Sh STANDARDS
The functions
are documented in
.Dq Advanced Sockets API for IPv6
(RFC2292).
.\"
.Sh BUGS
The text was shamelessly copied from RFC2292.
.Pp
.Fn inet6_rthdr_reverse
is not implemented yet.