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33 .\" Author: Archie Cobbs <archie@FreeBSD.org>
35 .\" $FreeBSD: src/share/man/man4/ng_ether.4,v 1.4.2.12 2002/04/07 04:57:13 dd Exp $
42 .Nd Ethernet netgraph node type
44 .In netgraph/ether/ng_ether.h
48 netgraph node type allows Ethernet interfaces to interact with
54 module is loaded in the kernel, a node is automatically created
55 for each Ethernet interface in the system.
56 Each node will attempt to name itself with the same name
57 as the associated interface.
60 nodes are persistent for as long as the interface itself exists.
62 Three hooks are supported:
69 may be used as an alias for
71 and is provided for backward compatibility.
72 In reality the two names represent the same hook.
76 hook is a connection to the raw Ethernet device.
77 When connected, all incoming packets are diverted out this hook.
78 Writing to this hook results in a raw Ethernet frame being transmitted
80 Normal outgoing packets are not affected by
86 hook is a connection to the upper protocol layers.
87 When connected, all outgoing packets are diverted out this hook.
88 Writing to this hook results in a raw Ethernet frame being received by
89 the kernel just as if it had come in over the wire.
90 Normal incoming packets are not affected by
98 except that only unrecognized packets (that would otherwise be discarded)
99 are written to the hook, and normal incoming traffic is unaffected.
104 may be connected at any time.
106 In all cases, frames are raw Ethernet frames with the standard
107 14 byte Ethernet header (but no checksum).
109 When no hooks are connected,
113 are in effect connected together,
114 so that packets flow normally upwards and downwards.
116 This node type supports the following hooks:
117 .Bl -tag -width orphans
119 Connection to the lower device link layer.
121 Connection to the upper protocol layers.
125 but only receives unrecognized packets.
128 This node type supports the generic control messages, plus the following:
130 .It Dv NGM_ETHER_GET_IFNAME
131 Returns the name of the associated interface as a NUL-terminated ASCII string.
132 Normally this is the same as the name of the node.
133 .It Dv NGM_ETHER_GET_IFINDEX
134 Returns the global index of the associated interface as a 32 bit integer.
135 .It Dv NGM_ETHER_GET_ENADDR
136 Returns the device's unique six byte Ethernet address.
137 .It Dv NGM_ETHER_SET_ENADDR
138 Sets the device's unique six byte Ethernet address.
139 This control message is equivalent to using the
143 .It Dv NGM_ETHER_SET_PROMISC
144 Enable or disable promiscuous mode.
145 This message includes a single 32 bit integer flag that enables or
146 disables promiscuous mode on the interface.
147 .It Dv NGM_ETHER_GET_PROMISC
148 Get the current value of the node's promiscuous flag.
149 The returned value is always either one or zero.
150 Note that this flag reflects the node's own promiscuous setting
151 and does not necessarily reflect the promiscuous state of the actual
152 interface, which can be affected by other means (e.g.,
154 .It Dv NGM_ETHER_SET_AUTOSRC
155 Sets the automatic source address override flag.
156 This message includes a single 32 bit integer flag that causes
157 all outgoing packets to have their source Ethernet
158 address field overwritten with the device's unique Ethernet address.
159 If this flag is set to zero, the source address in outgoing packets
161 The default setting for this flag is enabled.
162 .It Dv NGM_ETHER_GET_AUTOSRC
163 Get the current value of the node's source address override flag.
164 The returned value is always either one or zero.
167 This node is persistent for as long as the interface exists.
170 control message, all hooks are disconnected, promiscuous mode is disabled,
171 and the source address override flag is reenabled,
172 but the node is not removed.
173 If the interface itself is detached (e.g., because of PCCARD removal), the
174 node disappears as well.
176 This command dumps all unrecognized packets received by the
178 interface to standard output decoded in hex and ASCII:
179 .Bd -literal -offset indent
180 nghook -a fxp0: orphans
183 This command sends the contents of
187 .Bd -literal -offset indent
188 cat foo.pkt | nghook fxp0: orphans
191 These commands insert an
193 node between the lower and upper protocol layers, which can be used for
194 tracing packet flow, statistics, etc.:
195 .Bd -literal -offset indent
196 ngctl mkpeer fxp0: tee lower right
197 ngctl connect fxp0: lower upper left
207 .An Julian Elischer Aq Mt julian@FreeBSD.org
208 .An Archie Cobbs Aq Mt archie@FreeBSD.org
210 The automatic KLD module loading mechanism that works for most
211 other netgraph node types does not work for the
216 nodes are not created on demand; instead, they are created when
217 Ethernet interfaces are attached or when the KLD is first loaded.
218 Therefore, if the KLD is not statically compiled into the kernel,
219 it is necessary to load the KLD manually in order to bring the
221 nodes into existence.