xref: /freebsd/share/man/man4/ng_iface.4 (revision 7bd6fde3)
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33.\" Author: Archie Cobbs <archie@FreeBSD.org>
34.\"
35.\" $FreeBSD$
36.\" $Whistle: ng_iface.8,v 1.5 1999/01/25 23:46:26 archie Exp $
37.\"
38.Dd October 28, 2005
39.Dt NG_IFACE 4
40.Os
41.Sh NAME
42.Nm ng_iface
43.Nd interface netgraph node type
44.Sh SYNOPSIS
45.In netgraph/ng_iface.h
46.Sh DESCRIPTION
47An
48.Nm iface
49node is both a netgraph node and a system networking interface.
50When an
51.Nm iface
52node is created, a new interface appears which is accessible via
53.Xr ifconfig 8 .
54.Nm Iface
55node interfaces are named
56.Dv ng0 ,
57.Dv ng1 ,
58etc.
59When a node is shutdown, the corresponding interface is removed
60and the interface name becomes available for reuse by future
61.Nm iface
62nodes; new nodes always take the first unused interface.
63The node itself is assigned the same name as its interface, unless the name
64already exists, in which case the node remains unnamed.
65.Pp
66An
67.Nm iface
68node has a single hook corresponding to each supported protocol.
69Packets transmitted via the interface flow out the corresponding
70protocol-specific hook.
71Similarly, packets received on a hook appear on the interface as
72packets received into the corresponding protocol stack.
73The currently supported protocols are IP, IPv6, AppleTalk, IPX, ATM,
74NATM, and NS.
75.Pp
76An
77.Nm iface
78node can be configured as a point-to-point interface or a broadcast interface.
79The configuration can only be changed when the interface is down.
80The default mode is point-to-point.
81.Pp
82.Nm Iface
83nodes support the Berkeley Packet Filter (BPF).
84.Sh HOOKS
85This node type supports the following hooks:
86.Pp
87.Bl -tag -width foobar
88.It Dv inet
89Transmission and reception of IP packets.
90.It Dv inet6
91Transmission and reception of IPv6 packets.
92.It Dv atalk
93Transmission and reception of AppleTalk packets.
94.It Dv ipx
95Transmission and reception of IPX packets.
96.It Dv atm
97Transmission and reception of ATM packets.
98.It Dv natm
99Transmission and reception of NATM packets.
100.It Dv ns
101Transmission and reception of NS packets.
102.El
103.Sh CONTROL MESSAGES
104This node type supports the generic control messages, plus the following:
105.Bl -tag -width foo
106.It Dv NGM_IFACE_GET_IFNAME
107Returns the name of the associated interface as a
108.Dv NUL Ns -terminated
109.Tn ASCII
110string.
111Normally this is the same as the name of the node.
112.It Dv NGM_IFACE_GET_IFINDEX
113Returns the global index of the associated interface as a 32 bit integer.
114.It Dv NGM_IFACE_POINT2POINT
115Set the interface to point-to-point mode.
116The interface must not currently be up.
117.It Dv NGM_IFACE_BROADCAST
118Set the interface to broadcast mode.
119The interface must not currently be up.
120.It Dv NGM_CISCO_GET_IPADDR
121This message is defined by the
122.Xr ng_cisco 4
123node type; see
124.Xr ng_cisco 4
125for a description.
126.El
127.Sh SHUTDOWN
128This node shuts down upon receipt of a
129.Dv NGM_SHUTDOWN
130control message.
131The associated interface is removed and becomes available
132for use by future
133.Nm iface
134nodes.
135.Pp
136Unlike most other node types, an
137.Nm iface
138node does
139.Em not
140go away when all hooks have been disconnected; rather, and explicit
141.Dv NGM_SHUTDOWN
142control message is required.
143.Sh ALTQ Support
144The
145.Nm
146interface supports ALTQ bandwidth management feature.
147However,
148.Nm
149is a special case, since it is not a physical interface with limited bandwidth.
150One should not turn ALTQ on
151.Nm
152if the latter corresponds to some tunneled connection, e.g.\& PPPoE or PPTP.
153In this case, ALTQ should be configured on the interface that is used to
154transmit the encapsulated packets.
155In case when your graph ends up with some kind of serial line, either
156synchronous or modem, the
157.Nm
158is the right place to turn ALTQ on.
159.Sh SEE ALSO
160.Xr altq 4 ,
161.Xr bpf 4 ,
162.Xr netgraph 4 ,
163.Xr ng_cisco 4 ,
164.Xr ifconfig 8 ,
165.Xr ngctl 8
166.Sh HISTORY
167The
168.Nm iface
169node type was implemented in
170.Fx 4.0 .
171.Sh AUTHORS
172.An Archie Cobbs Aq archie@FreeBSD.org
173