Choosing an exit node on Windows did nothing: the using side was refused,
because Windows has no per-user routing and the agent's own traffic would loop
into the tunnel it carries.
Now the overlay interface gets 0.0.0.0/1 and 128.0.0.0/1 routes (and ::/1,
8000::/1 as an IPv6 blackhole), and every underlay address the agent talks to
directly gets a /32 route through the physical default gateway, marked with
route metric 7373 so stale ones are found and removed. Bypass routes are
written before the halves and removed after them; a failed step removes what
was written. All routes are in the active store.
The addresses come from the runtime: each network runtime hands the interface
the verified direct IPv4 paths of its control connections and the relay hosts
in use (Interface::set_underlay, refreshed every dial round); relay names are
resolved when the rules are applied. ExitHostRules::needs_bypass (true only on
Windows) gates it, so Linux and macOS plans never carry or re-apply on path
changes. ExitHostPlan gains `bypass` and `bypass_hosts`; networks leaving
forget their entry.
Limits: a path that appears after the last apply goes through the tunnel until
the next apply; data-plane-only addresses are not collected separately (the
data links ride the same iroh paths). Nothing was run on Windows.
Checks: cargo fmt --check, cargo clippy --locked --workspace --all-targets
-D warnings and cargo test --locked --workspace --all-targets passed on macOS;
scripts and ordering are unit-tested with an injected runner and resolver, and
Interface::set_underlay with the mock host.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
UltradesuandClaude Sonnet 5.5
7c176e0b74