Restore DNS policy parity under WireGuard - #738
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A computed checksum of zero is mapped to 0xffff only for UDP, where zero means "no checksum" (RFC 768). TCP has no such convention, so encoding a zero there corrupted the rewritten segment; because every retransmission is rewritten identically, the receiver would have dropped each copy and the DNS-over-TCP lookup would hang instead of failing fast. Also drop the per-segment clone of the reassembly buffer: the residual frame can be up to 64 KiB, so cloning it for every arriving segment made frame detection quadratic in the size of a TCP response.
kasnder
marked this pull request as ready for review
August 20, 2026 10:18
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Summary
DNS =line, so the UI no longer claims that an inert DoH proxy is active and the app does not send DoH outside the tunnelVerification
cargo test: 30 passed:app:testGithubDebugUnitTest: 219 passed, 0 failuresassembleGithubDebug: passed, including native C and Rust for all four Android ABIsadb install -r: existing WireGuard profile with noDNS =line stayed connectedSecure DNS proxy disabled while WireGuard egress is active; the original disabled preference and active VPN were restored afterwardKnown limit
DNS-over-TCP responses split across segments are recorded but deliberately left unchanged. Rewriting those safely requires buffering plus TCP sequence translation; continuation segments cannot be treated as fresh DNS frames.
Closes #734
Closes #736