This defaults to 1500 for all adapters, but LoopbackAdapter increases
it to 65536 on construction.
If an IPv4 packet is larger than the MTU, we'll need to break it into
smaller fragments before transmitting it. This part is a FIXME. :^)
This is useful for static locals that never need to be destroyed:
Thing& Thing::the()
{
static Eternal<Thing> the;
return the;
}
The object will be allocated in data segment memory and will never have
its destructor invoked.
Choosing adapter for transmit is done by adapter_for_route_to(IPv4Address).
This is just hard-coded logic right now but can be expanded to support a
proper routing table.
Also start moving kernel networking code into Kernel/Net/.
