.\" $Id: inet_cidr.3,v 8.2 1999/01/08 18:54:24 vixie Exp $
.\"
.\"Copyright (c) 1998,1999 by Internet Software Consortium
.\"
.\"Permission to use, copy, modify, and distribute this software for any
.\"purpose with or without fee is hereby granted, provided that the above
.\"copyright notice and this permission notice appear in all copies.
.\"
.\"THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
.\"ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
.\"OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
.\"CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
.\"DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
.\"PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
.\"ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
.\"SOFTWARE.
.\"
.Dd October 19, 1998
.Dt INET_CIDR 3 
.Os BSD 4
.Sh NAME
.Nm inet_cidr_ntop ,
.Nm inet_cidr_pton
.Nd network translation routines
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/socket.h>
.Fd #include <netinet/in.h>
.Fd #include <arpa/inet.h>
.Fn inet_cidr_ntop "int af" "const void *src" "int bits" "char *dst" "size_t size"
.Fn inet_cidr_pton "int af" "const char *src" "void *dst" "int *bits"
.Sh DESCRIPTION
These routines are used for converting addresses to and from network and
presentation forms with CIDR (Classless Inter-Domain Routing) representation,
embedded net mask.
.Pp
.Bd -literal
		130.155.16.1/20
.Ed
.\"		::ffff:130.155.16.1/116
.Pp
.Fn inet_cidr_ntop
converts an address from network to presentation format.
.Pp
.Ft af
describes the type of address that is being passed in
.Ft src. 
.\"Currently defined types are AF_INET and AF_INET6.
Currently only AF_INET is supported.
.Pp
.Ft src
is an address in network byte order, its length is determined from
.Ft af.
.Pp
.Ft bits
specifies the number of bits in the netmask unless it is -1 in which case
the CIDR representation is omitted.
.Pp
.Ft dst
is a caller supplied buffer of at least
.Ft size
bytes.
.Pp
.Fn inet_cidr_ntop
returns 
.Ft dst
on success or NULL.
Check errno for reason.
.Pp
.Fn inet_cidr_pton
converts and address from presentation format, with optional CIDR
reperesentation, to network format.
The resulting address is zero filled if there were insufficint bits in
.Ft src.
.Pp
.Ft af
describes the type of address that is being passed in via 
.Ft src
and determines the size of 
.Ft dst.
.Pp
.Ft src
is an address in presentation format.
.Pp
.Ft bits
returns the number of bits in the netmask or -1 if a CIDR representation was
not supplied.
.Pp
.Fn inet_cidr_pton
returns 0 on succces or -1 on error.
Check errno for reason.
ENOENT indicates an invalid netmask.
.Sh SEE ALSO
.Xr intro 2