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: