ng_gif — generic
tunnel interface netgraph node type
The ng_gif netgraph node type allows
gif(4)
interfaces to interact with the
netgraph(4)
networking subsystem. Once the ng_gif module is
loaded in the kernel, a node is automatically created for each
gif(4)
interface in the system. Each node will attempt to name itself with the same
name as the associated interface. All ng_gif nodes
are persistent for as long as the interface itself exists.
Two hooks are supported: lower and
orphans. The hook name
divert may be used as an alias for
lower, and is provided for compatibility with
ng_ether(4).
In reality the two names represent the same hook.
The lower hook is a connection to the raw
gif(4)
device. When connected, all incoming packets are diverted out this hook.
Writing to this hook results in a raw encapsulated packet being transmitted
by the device. Normal outgoing packets are not affected by
lower being connected.
The orphans hook is equivalent to
lower, except that only unrecognized packets (that
would otherwise be discarded) are written to the hook, and normal incoming
traffic is unaffected. At most one of orphans and
lower may be connected at any time.
In all cases, frames are raw packets with the address family of
the packet attached to the front.
When no hooks are connected, packets flow normally upwards and
downwards.
This node type supports the following hooks:
- lower
- Connection to the lower device link layer.
- orphans
- Like
lower, but only receives unrecognized
packets.
This node type supports only the generic control messages.
This command dumps all unrecognized packets received by the
gif0 interface to standard output decoded in hex and
ASCII:
nghook -a gif0: orphans