xref: /freebsd/share/man/man4/ng_iface.4 (revision ad30f8e79bd1007cc2476e491bd21b4f5e389e0a)
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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.Bl -tag -width foobar
87.It Dv inet
88Transmission and reception of IP packets.
89.It Dv inet6
90Transmission and reception of IPv6 packets.
91.It Dv atalk
92Transmission and reception of AppleTalk packets.
93.It Dv ipx
94Transmission and reception of IPX packets.
95.It Dv atm
96Transmission and reception of ATM packets.
97.It Dv natm
98Transmission and reception of NATM packets.
99.It Dv ns
100Transmission and reception of NS packets.
101.El
102.Sh CONTROL MESSAGES
103This node type supports the generic control messages, plus the following:
104.Bl -tag -width foo
105.It Dv NGM_IFACE_GET_IFNAME
106Returns the name of the associated interface as a
107.Dv NUL Ns -terminated
108.Tn ASCII
109string.
110Normally this is the same as the name of the node.
111.It Dv NGM_IFACE_GET_IFINDEX
112Returns the global index of the associated interface as a 32 bit integer.
113.It Dv NGM_IFACE_POINT2POINT
114Set the interface to point-to-point mode.
115The interface must not currently be up.
116.It Dv NGM_IFACE_BROADCAST
117Set the interface to broadcast mode.
118The interface must not currently be up.
119.It Dv NGM_CISCO_GET_IPADDR
120This message is defined by the
121.Xr ng_cisco 4
122node type; see
123.Xr ng_cisco 4
124for a description.
125.El
126.Sh SHUTDOWN
127This node shuts down upon receipt of a
128.Dv NGM_SHUTDOWN
129control message.
130The associated interface is removed and becomes available
131for use by future
132.Nm iface
133nodes.
134.Pp
135Unlike most other node types, an
136.Nm iface
137node does
138.Em not
139go away when all hooks have been disconnected; rather, and explicit
140.Dv NGM_SHUTDOWN
141control message is required.
142.Sh ALTQ Support
143The
144.Nm
145interface supports ALTQ bandwidth management feature.
146However,
147.Nm
148is a special case, since it is not a physical interface with limited bandwidth.
149One should not turn ALTQ on
150.Nm
151if the latter corresponds to some tunneled connection, e.g.\& PPPoE or PPTP.
152In this case, ALTQ should be configured on the interface that is used to
153transmit the encapsulated packets.
154In case when your graph ends up with some kind of serial line, either
155synchronous or modem, the
156.Nm
157is the right place to turn ALTQ on.
158.Sh SEE ALSO
159.Xr altq 4 ,
160.Xr bpf 4 ,
161.Xr netgraph 4 ,
162.Xr ng_cisco 4 ,
163.Xr ifconfig 8 ,
164.Xr ngctl 8
165.Sh HISTORY
166The
167.Nm iface
168node type was implemented in
169.Fx 4.0 .
170.Sh AUTHORS
171.An Archie Cobbs Aq archie@FreeBSD.org
172