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.\" Id: inet_cidr.man3,v 1.2 2009/01/21 00:12:34 each Exp 
.\"
.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