163 lines
4.5 KiB
Groff
163 lines
4.5 KiB
Groff
.\" $NetBSD: getifaddrs.3,v 1.2 2000/02/23 15:29:18 itojun Exp $
|
|
.\" BSDI getifaddrs.3,v 2.5 2000/02/23 14:51:59 dab Exp
|
|
.\"
|
|
.\" Copyright (c) 1995, 1999
|
|
.\" Berkeley Software Design, Inc. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.Dd "October 12, 1995"
|
|
.Dt GETIFADDRS 3
|
|
.Sh NAME
|
|
.Nm getifaddrs
|
|
.Nd get interface addresses
|
|
.Sh SYNOPSIS
|
|
.Fd #include <sys/types.h>
|
|
.Fd #include <sys/socket.h>
|
|
.Fd #include <ifaddrs.h>
|
|
.Ft int
|
|
.Fn getifaddrs "struct ifaddrs **ifap"
|
|
.Ft void
|
|
.Fn freeifaddrs "struct ifaddrs *ifp"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn getifaddrs
|
|
function stores a reference to a linked list of the network interfaces
|
|
on the local machine in the memory referenced by
|
|
.Fa ifap .
|
|
The list consists of
|
|
.Nm ifaddrs
|
|
structures, as defined in the include file
|
|
.Aq Pa ifaddrs.h .
|
|
The
|
|
.Nm ifaddrs
|
|
structure contains at least the following entries:
|
|
.Bd -literal
|
|
struct ifaddrs *ifa_next; /* Pointer to next struct */
|
|
char *ifa_name; /* Interface name */
|
|
u_int ifa_flags; /* Interface flags */
|
|
struct sockaddr *ifa_addr; /* Interface address */
|
|
struct sockaddr *ifa_netmask; /* Interface netmask */
|
|
struct sockaddr *ifa_broadaddr; /* Interface broadcast address */
|
|
struct sockaddr *ifa_dstaddr; /* P2P interface destination */
|
|
void *ifa_data; /* Address specific data */
|
|
.Ed
|
|
.Pp
|
|
The
|
|
.Li ifa_next
|
|
field contains a pointer to the next structure on the list.
|
|
This field is
|
|
.Dv NULL
|
|
in last structure on the list.
|
|
.Pp
|
|
The
|
|
.Li ifa_name
|
|
field contains the interface name.
|
|
.Pp
|
|
The
|
|
.Li ifa_flags
|
|
field contains the interface flags, as set by
|
|
.Xr ifconfig 8
|
|
utility.
|
|
.Pp
|
|
The
|
|
.Li ifa_addr
|
|
field references either the address of the interface or the link level
|
|
address of the interface, if one exists, otherwise it is NULL.
|
|
(The
|
|
.Li sa_family
|
|
field of the
|
|
.Li ifa_addr
|
|
field should be consulted to determine the format of the
|
|
.Li ifa_addr
|
|
address.)
|
|
.Pp
|
|
The
|
|
.Li ifa_netmask
|
|
field references the netmask associated with
|
|
.Li ifa_addr ,
|
|
if one is set, otherwise it is NULL.
|
|
.Pp
|
|
The
|
|
.Li ifa_broadaddr
|
|
field,
|
|
which should only be referenced for non-P2P interfaces,
|
|
references the broadcast address associated with
|
|
.Li ifa_addr ,
|
|
if one exists, otherwise it is NULL.
|
|
.Pp
|
|
The
|
|
.Li ifa_dstaddr
|
|
field references the destination address on a P2P interface,
|
|
if one exists, otherwise it is NULL.
|
|
.Pp
|
|
The
|
|
.Li ifa_data
|
|
field references address family specific data. For
|
|
.Dv AF_LINK
|
|
addresses it contains a pointer to the
|
|
.Fa struct if_data
|
|
.Pq as defined in include file Aq Pa net/if.h
|
|
which contains various interface attributes and statistics.
|
|
For all other address families, it contains a pointer to the
|
|
.Fa struct ifa_data
|
|
.Pq as defined in include file Aq Pa net/if.h
|
|
which contains per-address interface statistics.
|
|
.Pp
|
|
The data returned by
|
|
.Fn getifaddrs
|
|
is dynamically allocated and should be freed using
|
|
.Fn freeifaddrs
|
|
when no longer needed.
|
|
.Sh RETURN VALUES
|
|
Upon successful completion, a value of 0 is returned.
|
|
Otherwise, a value of -1 is returned and
|
|
.Va errno
|
|
is set to indicate the error.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn getifaddrs
|
|
may fail and set
|
|
.Va errno
|
|
for any of the errors specified for the library routines
|
|
.Xr ioctl 2 ,
|
|
.Xr socket 2 ,
|
|
.Xr malloc 3
|
|
or
|
|
.Xr sysctl 3 .
|
|
.Sh BUGS
|
|
If both
|
|
.Aq Pa net/if.h
|
|
and
|
|
.Aq Pa ifaddrs.h
|
|
are being included,
|
|
.Aq Pa net/if.h
|
|
.Em must
|
|
be included before
|
|
.Aq Pa ifaddrs.h .
|
|
.Sh SEE ALSO
|
|
.Xr ioctl 2 ,
|
|
.Xr socket 2 ,
|
|
.Xr sysctl 3 ,
|
|
.Xr networking 4 ,
|
|
.Xr ifconfig 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
implementation first appeared in BSDI BSD/OS.
|