feat: name each tunnel from the process that owns it, not from its address - #102
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…dress Anything that is not GlobalProtect showed as "VPN (utun7)", because the only thing we could say about a tunnel was its interface name and its address — and the address is ambiguous. CGNAT 100.64/10 is shared ground between Tailscale, NetBird, Netmaker, Twingate, Zscaler and Cloudflare WARP, which is why #99 arrived as "NetBird is not detected": nothing on screen ever said NetBird. The tunnel already knows who made it. A utun is created by opening a kernel control socket named com.apple.net.utun_control, and the creating process holds that descriptor for the tunnel's whole life, so proc_pidfdinfo(PROC_PIDFDSOCKETINFO) reports it as SOCKINFO_KERN_CTL with the control unit attached. That is an exact answer with no vendor list, no CLI and no network call. It has to be privileged. Every VPN daemon that matters runs as uid 0, and an unprivileged sweep cannot read their descriptor lists — 206 of 783 and 322 of 725 processes denied on two machines, with every VPN tunnel in the denied set. So the sweep is a read-only helper method and helperVersion goes to 2.2.0. Verified on real hardware rather than reasoned about. A process that creates a utun and reads its own name back through getsockopt(UTUN_OPT_IFNAME) reported utun6 while the sweep independently saw control unit 7, pinning the off-by-one from both ends. With a root-owned CGNAT tunnel up alongside Tailscale, a root sweep labelled utun2 Tailscale and utun5 NetBird in 3.4 ms, while the same binary run as the user saw neither. Two details the hardware surfaced. nesessionmanager holds the same control unit as the network extension it started, so a tunnel legitimately has more than one holder and the broker must never win. And matching the owner rather than scanning the whole process table lets the needles be strict: the old scan matched any line containing "cloudflare", so cloudflared — a common tunnel daemon that is not WARP — was reported as Cloudflare WARP. Labelling is cosmetic by construction. An empty reply means "could not ask", never "no tunnels", so an absent or older helper falls back to today's behaviour and the map never influences which tunnel gets routed.
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Included review availability: Your plan provides up to 2 included reviews per hour; 0 remain after this review. 📝 WalkthroughWalkthroughThe change adds privileged ChangesTunnel ownership attribution
Estimated code review effort: 4 (Complex) | ~45 minutes Merge Risk: ⚪ Minimal · up to The change adds process-based tunnel naming with a documented fallback path and does not present an actionable merge-blocking risk; it is merge-ready after normal checks and review. 🚥 Pre-merge checks | ✅ 5✅ Passed checks (5 passed)
Full details: Description checkExplanation The description provides a detailed summary, implementation rationale, testing evidence, compatibility behavior, and known limitations. It does not use the repository template headings or checklist items, but the core required information is present. Full details: Linked Issues checkExplanation The implementation satisfies issue Full details: Out of Scope Changes checkExplanation The helper version update, XPC signature changes, build updates, ownership mapping, fallback handling, and tests directly support issue ✨ Finishing Touches📝 Generate docstrings
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In `@Sources/VPNBypassCore/HelperProtocol.swift`:
- Line 77: Update listTunnelOwners and its HelperManager.tunnelOwners call path
to return an XPC-compatible success or failure status alongside the owners,
distinguishing an empty successful result from an unavailable or timed-out
helper. In the caller that updates ownership labels, clear stale ownership on
successful empty results but preserve the previous map when the request fails,
and explicitly handle the propagated error status.
In `@Sources/VPNBypassCore/RouteManager.swift`:
- Line 686: Move the await refreshTunnelOwners() call to the beginning of
detectVPNInterface(), before VPN interface/type detection, and remove the later
redundant invocation from the route detection flow.
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… deriving Both from review of the first commit, and the first one is worse than it looks. The XPC reply was a bare array, so an empty one meant either "the sweep ran and this machine has no tunnels" or "the helper is absent, too old, or timed out". To stay safe under an outage the map was never cleared on empty — which means it was never cleared at all. utun numbers are recycled: once Tailscale released utun2 and something else claimed it, the stale entry would have labelled the new tunnel Tailscale. The reply now carries an explicit success flag, nil means could-not-ask and keeps the previous map, and an empty result is applied like any other answer. The refresh also ran after the type had already been derived from the map, and the startup path calls detectVPNInterface directly without ever passing the later call site, so the first labels of every launch came from the interface-name guess. It now happens at the top of detectVPNInterface, the one funnel all three detection paths share. The merge decision is a pure static so both halves are testable; reverting it to the stale-map behaviour turns the recycling test red.
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Closes #101.
Anything that isn't GlobalProtect shows as
VPN (utun7), because the only things we could say about a tunnel were its interface name and its address — and the address is ambiguous. CGNAT100.64.0.0/10is shared ground between Tailscale, NetBird, Netmaker, Twingate, Zscaler and Cloudflare WARP. That ambiguity is why #99 arrived as "NetBird is not detected": nothing on screen ever said NetBird.The tunnel already knows who made it
A
utunis created by opening a kernel control socket namedcom.apple.net.utun_control, and the creating process holds that descriptor for the tunnel's whole life.proc_pidfdinfo(PROC_PIDFDSOCKETINFO)reports it asSOCKINFO_KERN_CTLwith the control unit attached. Exact, no vendor list, no CLI, no network call.It must be privileged, so it is a read-only helper method and
helperVersiongoes to 2.2.0.Verified on hardware, not reasoned about
The off-by-one, pinned from both ends. A process that creates a utun and reads its own name back through
getsockopt(UTUN_OPT_IFNAME), while the sweep independently reports its control unit:Two CGNAT tunnels, ambiguous by address, separated by owner. Mac mini, macOS 26.6.1, Tailscale connected and a root-owned tunnel on
100.88.0.2:That is the whole argument for putting it in the helper. Unprivileged, 206/783 and 322/725 processes were permission-denied across two machines, with every VPN tunnel in the denied set. Creating a utun at all is
EPERMunprivileged.The real NetBird daemon (0.77.1, installed and run for this test, then removed) reports as uid 0,
comm=/opt/homebrew/bin/netbird— confirming both the reporter's process name and that it would be invisible without the helper.Two details the hardware surfaced
nesessionmanagerholds the same control unit as the extension it started, so a tunnel legitimately has more than one holder. Attributing to the broker would label every NetworkExtension VPN identically, so brokers never win — but a broker alone still reports the tunnel, because knowing one exists beats dropping it.cloudflare, socloudflared— a common tunnel daemon that is not WARP — read as Cloudflare WARP. Tested, and it no longer does.Cosmetic by construction
An empty reply means "could not ask", never "no tunnels". An absent or older helper falls back to today's labelling, the map never influences which tunnel gets routed, and a failed call never clears a good map (labels would flicker between polls otherwise).
detectVPNStateOnly— the no-helper path — is unaffected.Evidence
1053 tests, 0 failures. 15 new, with fixtures taken from the real mini capture rather than invented. Mutation-checked: dropping the broker filter fails 3, breaking the off-by-one fails 12.
What is not covered: I could not get a real NetBird tunnel — that needs a management account — so the CGNAT tunnel above was created directly and held by a process named for the test. The mechanism is identical; the NetBird-specific part verified is its daemon name and uid.
Summary by CodeRabbit
New Features
Bug Fixes
Improvements