xref: /freebsd/share/man/man4/ng_iface.4 (revision 6ae1554a5d9b318f8ad53ccc39fa5a961403da73)
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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 January 12, 2015
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, ATM, NATM, and NS.
74.Pp
75An
76.Nm iface
77node can be configured as a point-to-point interface or a broadcast interface.
78The configuration can only be changed when the interface is down.
79The default mode is point-to-point.
80.Pp
81.Nm Iface
82nodes support the Berkeley Packet Filter (BPF).
83.Sh HOOKS
84This node type supports the following hooks:
85.Bl -tag -width ".Va inet6"
86.It Va inet
87Transmission and reception of IP packets.
88.It Va inet6
89Transmission and reception of IPv6 packets.
90.It Va atm
91Transmission and reception of ATM packets.
92.It Va natm
93Transmission and reception of NATM packets.
94.It Va ns
95Transmission and reception of NS packets.
96.El
97.Sh CONTROL MESSAGES
98This node type supports the generic control messages, plus the following:
99.Bl -tag -width foo
100.It Dv NGM_IFACE_GET_IFNAME Pq Ic getifname
101Returns the name of the associated interface as a
102.Dv NUL Ns -terminated
103.Tn ASCII
104string.
105Normally this is the same as the name of the node.
106.It Dv NGM_IFACE_GET_IFINDEX Pq Ic getifindex
107Returns the global index of the associated interface as a 32 bit integer.
108.It Dv NGM_IFACE_POINT2POINT Pq Ic point2point
109Set the interface to point-to-point mode.
110The interface must not currently be up.
111.It Dv NGM_IFACE_BROADCAST Pq Ic broadcast
112Set the interface to broadcast mode.
113The interface must not currently be up.
114.El
115.Sh SHUTDOWN
116This node shuts down upon receipt of a
117.Dv NGM_SHUTDOWN
118control message.
119The associated interface is removed and becomes available
120for use by future
121.Nm iface
122nodes.
123.Pp
124Unlike most other node types, an
125.Nm iface
126node does
127.Em not
128go away when all hooks have been disconnected; rather, and explicit
129.Dv NGM_SHUTDOWN
130control message is required.
131.Sh ALTQ Support
132The
133.Nm
134interface supports ALTQ bandwidth management feature.
135However,
136.Nm
137is a special case, since it is not a physical interface with limited bandwidth.
138One should not turn ALTQ on
139.Nm
140if the latter corresponds to some tunneled connection, e.g.\& PPPoE or PPTP.
141In this case, ALTQ should be configured on the interface that is used to
142transmit the encapsulated packets.
143In case when your graph ends up with some kind of serial line, either
144synchronous or modem, the
145.Nm
146is the right place to turn ALTQ on.
147.Sh SEE ALSO
148.Xr altq 4 ,
149.Xr bpf 4 ,
150.Xr netgraph 4 ,
151.Xr ng_cisco 4 ,
152.Xr ifconfig 8 ,
153.Xr ngctl 8
154.Sh HISTORY
155The
156.Nm iface
157node type was implemented in
158.Fx 4.0 .
159.Sh AUTHORS
160.An Archie Cobbs Aq Mt archie@FreeBSD.org
161