When we read interface flags and capabilities from the kernel, take
care not to record them in our current environment (env), but record
them in the output environment (oenv), instead. This helps us get
interface capabilities and flags right.
improved modularity and extensibility.
In the new architecture, a directed graph of argument-matching
objects (match objects) expresses the set of feasible ifconfig
statements. Match objects are labelled by subroutines that provide
the statement semantics.
Many IPv4, IPv6, 802.11, tunnel, and media configurations have been
tested.
AppleTalk, ISO, carp(4), agr(4), and vlan(4) configuration need
testing.