Absorb upstream #21: don't pre-install unvalidated peer endpoints - #4
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…DISCO validates At peer-add, the peer's advertised endpoints[0] from the MapResponse was installed as the WireGuard endpoint before any path validation, and wireguardif's output path treats any non-zero endpoint as a working direct path. For a CGNAT peer (e.g. cellular hotspot) that address is unreachable, so the tunnel went one-way: inbound arrived via DERP while every outbound data packet was sent direct-UDP into a black hole. Tailscale semantics: data flows via DERP until a direct path is validated by a DISCO pong. Leave the endpoint blank at peer-add; the only endpoint installs are the already-gated ones (process_disco_pong on a direct pong, and the handshake path gated on best_ip). Same-LAN peers still upgrade to direct within seconds. Verified on ESP32-S3 (ESP-IDF v5.3): a CGNAT peer that previously could never reach a TCP service on the node (ping timeout, connect fail) gets ping replies over DERP, TCP connects, and bulk transfers complete. Same-LAN direct path unaffected. Fixes #18 (cherry picked from commit da55beb) Upstream-PR: CamM2325#21 Upstream-Issue: CamM2325#18
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Cherry-picks
da55beb7from CamM2325/microlink#21 by @snowpaper (fixes CamM2325/microlink#18), unchanged aside from a provenance trailer. Author attribution preserved viagit cherry-pick -x.Why we're absorbing this ourselves: upstream has had zero maintainer activity (no comments, no reviews) on any open PR since the last commit on 2026-03-17. Six PRs are open and unreviewed; this is one of three we're pulling in because they're clean, well-verified fixes.
What it fixes: at peer-add, the peer's advertised endpoint (unvalidated) was installed as the WireGuard endpoint, and
wireguardif's output path treats any non-zero endpoint as a working direct path. For a CGNAT peer (e.g. phone on cellular) that address is unreachable — the tunnel goes one-way: inbound via DERP, every outbound packet into a black hole. Fix follows Tailscale's own semantics: leave the endpoint blank until a DISCO pong validates a direct path.Applied cleanly (
git apply --check) against our diverged fork. Built clean forlilygo-t-display-s3(ESP-IDF 6.0.1) in the downstream ZenClock project. SeeUPSTREAM_PRS.md(added in a follow-up) for the full absorption record.