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.\" Author: Archie Cobbs <archie@whistle.com>
.\"
.\" $FreeBSD$
.\" $Whistle: ng_iface.8,v 1.5 1999/01/25 23:46:26 archie Exp $
.\"
.Dd January 19, 1999
.Dt NG_IFACE 8
.Os FreeBSD 3
.Sh NAME
.Nm ng_iface
.Nd interface netgraph node type
.Sh SYNOPSIS
.Fd #include <netgraph/ng_iface.h>
.Sh DESCRIPTION
An
.Nm iface
node is both a netgraph node and a system networking interface.  When an
.Nm iface
node is created, a new point-to-point interface appears which is accessible via
.Xr ifconfig 8 .
The new interfaces are named
.Dv ng0 ,
.Dv ng1 ,
etc.  The node is assigned the same name as its interface, unless the name
already exists, in which case the node remains unnamed.
.Pp
.Nm Iface
nodes have a single hook corresponding to each supported protocol.
Packets transmitted via the interface flow out the corresponding
protocol-specific hook.
Similarly, packets received on a hook appear on the interface as 
packets received in the corresponding protocol.
.Pp
The currently supported protocols are IP, IPX, AppleTalk, and NS.
In the KLD module, only support for IP is compiled in by default.
.Pp
.Nm Iface
nodes support the Berkeley Packet Filter (BPF). 
In the KLD module, this support is disabled by default.
.Sh HOOKS
This node type supports the following hooks:
.Pp
.Bl -tag -width foobar
.It Dv inet
Transmission and reception of IP packets.
.It Dv ipx
Transmission and reception of IPX packets.
.It Dv atalk
Transmission and reception of AppleTalk packets.
.It Dv ns
Transmission and reception of NS packets.
.El
.Sh CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
.Bl -tag -width foo
.It Dv NGM_IFACE_GET_IFNAME
Returns the name of the interface corresponding to this node in a
.Dv "struct ng_iface_ifname" :
.Bd -literal -offset 4n
struct ng_iface_ifname {
  char  ngif_name[NG_IFACE_IFACE_NAME_MAX + 1];
};
.Ed
.It Dv NGM_IFACE_GET_IFADDRS
Returns the list of addresses associated with this interface.
The list is returned in the same format as the
.Dv SIOCGIFCONF
ioctl().
.It Dv NGM_CISCO_GET_IPADDR
This message is defined by the
.Xr ng_cisco 8
node type; see
.Xr ng_cisco 8
for a description.
.El
.Sh SHUTDOWN
Because it is currently not possible to remove a system networking
interface in FreeBSD,
.Nm iface
nodes are
.Em persistent.
That is, once created they are never destroyed.
The receipt of a
.Dv NGM_SHUTDOWN
control message disconnects all hooks but does not remove the node.
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr bpf 4 ,
.Xr ng_cisco 8 ,
.Xr ng_rfc1490 8 ,
.Xr ngctl 8 ,
.Xr ifconfig 8 .
.Sh AUTHOR
Archie Cobbs <archie@whistle.com>